U.S. patent application number 12/056732 was filed with the patent office on 2008-10-02 for refrigerant suction structure in fixed displacement type piston compressor, and operation control method in fixed displacement type piston compressor.
This patent application is currently assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. Invention is credited to Nobuaki Hoshino, Masaki Ota, Xiaoliang Wang.
Application Number | 20080240928 12/056732 |
Document ID | / |
Family ID | 39563581 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080240928 |
Kind Code |
A1 |
Wang; Xiaoliang ; et
al. |
October 2, 2008 |
REFRIGERANT SUCTION STRUCTURE IN FIXED DISPLACEMENT TYPE PISTON
COMPRESSOR, AND OPERATION CONTROL METHOD IN FIXED DISPLACEMENT TYPE
PISTON COMPRESSOR
Abstract
An introduction passage of rotary valve has outlets for feeding
out refrigerant in a suction pressure zone toward each of
compression chambers. A switch portion in a shutoff state shuts off
a portion of the suction pressure zone within a compressor from the
outlets of the introduction passage. The switch portion includes a
valve body, a working pressure chamber, and a working pressure
applying portion. The working pressure chamber introduces a working
pressure that is applied to the valve body so as to arrange the
valve body at a communication position. The pressure in the suction
pressure zone acts against the pressure in the working pressure
chamber through the valve body.
Inventors: |
Wang; Xiaoliang;
(Kariya-shi, JP) ; Hoshino; Nobuaki; (Kariya-shi,
JP) ; Ota; Masaki; (Kariya-shi, JP) |
Correspondence
Address: |
KNOBLE, YOSHIDA & DUNLEAVY
EIGHT PENN CENTER, SUITE 1350, 1628 JOHN F KENNEDY BLVD
PHILADELPHIA
PA
19103
US
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
KARIYA-SHI
JP
|
Family ID: |
39563581 |
Appl. No.: |
12/056732 |
Filed: |
March 27, 2008 |
Current U.S.
Class: |
417/26 ;
417/269 |
Current CPC
Class: |
F04B 27/16 20130101;
F04B 27/1018 20130101; F04B 49/225 20130101 |
Class at
Publication: |
417/26 ;
417/269 |
International
Class: |
F04B 49/00 20060101
F04B049/00; F04B 27/08 20060101 F04B027/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2007 |
JP |
2007-084792 |
Mar 29, 2007 |
JP |
2007-088327 |
Claims
1. A refrigerant suction structure in a fixed displacement type
piston compressor, wherein the compressor comprises: a rotary shaft
coupled to an external drive source via a clutch; a plurality of
cylinder bores arranged around the rotary shaft; a plurality of
pistons defining compression chambers in the cylinder bores by
being respectively accommodated in the cylinder bores; a cam body
integrated with the rotary shaft, the cam body converting a
rotation of the rotary shaft into reciprocation of each of the
pistons; a suction pressure zone; and a rotary valve having an
introduction passage for introducing a refrigerant from the suction
pressure zone to each of the compression chambers, the rotary valve
integrally rotating with the rotary shaft, the suction pressure
zone having a portion within the compressor, and the introduction
passage having outlets for feeding out the refrigerant toward each
of the compression chambers, wherein the refrigerant suction
structure has a switch portion capable of being switched between a
communication state and a shutoff state, wherein the switch portion
in the communication state allows the portion of the suction
pressure zone within the compressor to communicate with the outlets
of the introduction passage, wherein the switch portion in the
shutoff state shuts off the portion of the suction pressure zone
within the compressor from the outlets of the introduction passage,
wherein the switch portion includes: a valve body capable of being
switched between a communication position and a shutoff position,
the valve body in the communication position allowing the portion
of the suction pressure zone within the compressor to communicate
with the outlets of the introduction passage, and the valve body in
the shutoff position shutting off the portion of the suction
pressure zone within the compressor from the outlets of the
introduction passage; a working pressure chamber introducing a
working pressure that is applied to the valve body so as to arrange
the valve body at the communication position; and a working
pressure applying portion applying the working pressure to the
working pressure chamber, and wherein the pressure in the suction
pressure zone acts against the pressure in the working pressure
chamber through the valve body.
2. The refrigerant suction structure according to claim 1, wherein
the switch portion has a working pressure recess, and the valve
body is slidably fitted into the working pressure recess, whereby
the valve body defines the working pressure chamber within the
working pressure recess, wherein the pressure of the portion of the
suction pressure zone within the compressor acts against the
pressure of the working pressure chamber via the valve body, and
wherein the switch portion is provided with a first return spring
for returning the valve body to the shutoff position from the
communication position.
3. The refrigerant suction structure according to claim 2, wherein
the introduction passage has an inlet for accepting the refrigerant
from the suction pressure zone, and wherein, in the case that the
switch portion is in the shutoff state, the valve body is arranged
in such a manner as to shut off the inlet of the introduction
passage from the portion of the suction pressure zone within the
compressor.
4. The refrigerant suction structure according to claim 3, wherein
the inlet of the introduction passage is positioned in an end
surface of the rotary valve, and the outlets of the introduction
passage are positioned in a peripheral surface of the rotary valve,
wherein a rotation axis of the rotary valve intersects the end
surface, wherein the refrigerant suction structure comprises: a
valve accommodation chamber rotatably accommodating the rotary
valve; and a guide cylinder surrounding the rotation axis outside
the valve accommodation chamber, wherein a cylinder interior of the
guide cylinder communicates with an inlet of the introduction
passage, wherein the valve body is slidably fitted to the guide
cylinder, the valve body has an internal passage communicating with
the cylinder interior of the guide cylinder, and the internal
passage has an inlet for accepting the refrigerant from the suction
pressure zone, wherein, in the case that the valve body exists at
the shutoff position, the inlet of the internal passage is shut off
by entering the working pressure recess, and wherein, in the case
that the valve body exists at the communication position, the inlet
of the internal passage is positioned outside the working pressure
recess, so that the inlet is exposed to the interior of the portion
of the suction pressure zone within the compressor.
5. The refrigerant suction structure according to claim 4, wherein
the guide cylinder is formed as an independent body from members of
the compressor other than the valve body, so as to be allowed to
move in a radial direction of the rotary shaft with respect to
members of the compressor other than the valve body.
6. The refrigerant suction structure according to claim 2, wherein
the introduction passage has an inlet for accepting the refrigerant
from the suction pressure zone, and the inlet of the introduction
passage is positioned in an end surface of the rotary valve,
wherein the outlets of the introduction passage are positioned in a
peripheral surface of the rotary valve, wherein the valve body is
fitted into the introduction passage from the inlet of the
introduction passage, and wherein, in the case that the switch
portion is in the shutoff state, the valve body is arranged in the
introduction passage in such a manner as to shut off the outlets of
the introduction passage from the portion of the suction pressure
zone within the compressor.
7. The refrigerant suction structure according to claim 6, wherein
the introduction passage has an in-shaft passage positioned in the
rotary shaft, and the in-shaft passage extends in a direction of a
rotation axis of the rotary shaft, wherein the outlets of the
introduction passage extend through a peripheral surface of the
rotary shaft so as to communicate with the in-shaft passage,
wherein the valve body is fitted into the in-shaft passage in such
a manner as to be slidable in a direction of the rotation axis
within the introduction passage, wherein the valve body is moved in
the direction of the rotation axis within the in-shaft passage, so
as to be switched between the communication position and the
shutoff position, and wherein the valve body at the shutoff
position shuts off the outlets of the introduction passage with
respect to the in-shaft passage.
8. The refrigerant suction structure according to claim 3, wherein
the switch portion has a flat valve seat surface, the valve body
has a flat seal surface, and the seal surface comes into surface
contact with the valve seat surface in a state in which the valve
body exists at the shutoff position.
9. The refrigerant suction structure according to claim 1, wherein
the compressor has a discharge pressure zone, wherein the working
pressure applying portion has an inflow passage reaching the
working pressure chamber from the discharge pressure zone, and
wherein the refrigerant in the discharge pressure zone is
introduced to the working pressure chamber via the inflow
passage.
10. The refrigerant suction structure according to claim 9, wherein
an oil separator is provided on the inflow passage, and the oil
separator separates oil from the refrigerant within the discharge
pressure zone, wherein a constriction is provided in a portion of
the inflow passage in a downstream side of the oil separator, and
wherein the portion of the inflow passage in the downstream side of
the oil separator serves as an oil passage introducing the oil
separated by the oil separator to the constriction.
11. The refrigerant suction structure according to claim 9, wherein
the discharge pressure zone has a portion within the compressor,
wherein the portion of the discharge pressure zone within the
compressor is connected to the portion of the suction pressure zone
within the compressor via an external refrigerant circuit, and the
external refrigerant circuit has a portion of the discharge
pressure zone, wherein the inflow passage is connected to the
portion of the discharge pressure zone of the external refrigerant
circuit, wherein the working pressure applying portion is provided
with an electromagnetic on-off valve for opening and closing the
inflow passage, and a check valve, and wherein the check valve is
arranged in a portion of the external refrigerant circuit in a
downstream side of a connection portion between the portion of the
discharge pressure zone in the external refrigerant circuit and the
inflow passage.
12. The refrigerant suction structure according to claim 1, wherein
the working pressure applying portion is provided with an
electromagnetic three-way valve, wherein the working pressure
chamber is connected to the electromagnetic three-way valve via a
common passage, wherein the electromagnetic three-way valve is
connected to a discharge pressure zone via a feed passage, wherein
the electromagnetic three-way valve is connected to a suction
pressure zone via a discharge passage, and wherein the
electromagnetic three-way valve is structured to be switched
between a first state, in which the common passage communicates
with the feed passage, and a second state, in which the common
passage communicates with the discharge passage.
13. The refrigerant suction structure according to claim 1, wherein
the compressor comprises: a cylinder block having the cylinder
bores; and a rear housing member coupled to the cylinder block, and
wherein the rear housing member has in it a suction chamber, and
the working pressure chamber is defined within the rear housing
member.
14. A refrigerant suction structure in a fixed displacement type
piston compressor, wherein the compressor comprises: a rotary shaft
coupled to an external drive source via a clutch; a plurality of
cylinder bores arranged around the rotary shaft; a plurality of
pistons defining compression chambers in the cylinder bores by
being respectively accommodated in the cylinder bores; a cam body
integrated with the rotary shaft, the cam body converting a
rotation of the rotary shaft into reciprocation of each of the
pistons; a suction pressure zone; and a rotary valve having an
introduction passage for introducing a refrigerant from the suction
pressure zone to each of the compression chambers, the rotary valve
integrally rotating with the rotary shaft, the suction pressure
zone having a portion within the compressor, and the introduction
passage having outlets for feeding out the refrigerant toward each
of the compression chambers, wherein the refrigerant suction
structure has a switch portion capable of being switched between a
communication state and a shutoff state, wherein the switch portion
in the communication state allows the portion of the suction
pressure zone within the compressor to communicate with the outlets
of the introduction passage, wherein the switch portion in the
shutoff state shuts off the portion of the suction pressure zone
within the compressor from the outlets of the introduction passage,
wherein the switch portion includes: a valve body capable of being
switched between a communication position and a shutoff position,
the valve body in the communication position allowing the portion
of the suction pressure zone within the compressor to communicate
with the outlets of the introduction passage, and the valve body in
the shutoff position shutting off the portion of the suction
pressure zone within the compressor from the outlets of the
introduction passage; and an electromagnetic driving portion
driving the valve body on the basis of an electromagnetic
force.
15. The refrigerant suction structure according to claim 14,
wherein the switch portion is provided with a second return spring
returning the valve body to the communication position, and wherein
the electromagnetic driving portion drives the valve body from the
communication position toward the shutoff position.
16. The refrigerant suction structure according to claim 15,
wherein the switch portion has a pressure recess, and the valve
body is slidably accommodated within the pressure recess, whereby
the valve body defines a pressure chamber within the pressure
recess, wherein the pressure chamber communicates with the portion
of the suction pressure zone within the compressor, wherein the
pressure in the portion of the suction pressure zone within the
compressor acts against the pressure in the pressure chamber via
the valve body, wherein the second return spring is accommodated in
the pressure chamber, and the second return spring urges the valve
body in a direction in which the valve body pops out from the
interior of the pressure recess, and wherein the electromagnetic
driving portion drives the valve body in such a manner as to push
the valve body into the pressure recess.
17. The refrigerant suction structure according to claim 14,
wherein the switch portion has a pressure recess, and the valve
body is slidably accommodated within the pressure recess, whereby
the valve body defines a pressure chamber within the pressure
recess, wherein the pressure chamber communicates with the portion
of the suction pressure zone within the compressor, wherein the
pressure in the portion of the suction pressure zone within the
compressor acts against the pressure in the pressure chamber via
the valve body, wherein the switch portion is provided with a
retaining spring which acts to retain the valve body at the shutoff
position by pressing the valve body into the pressure recess, and
wherein the electromagnetic driving portion drives the valve body
from the communication position toward the shutoff position.
18. The refrigerant suction structure according to claim 17,
wherein the introduction passage has an inlet for accepting the
refrigerant from the suction pressure zone, and wherein, in the
case that the switch portion is in the shutoff state, the valve
body is arranged in such a manner as to shut off the inlet of the
introduction passage from the portion of the suction pressure zone
within the compressor.
19. The refrigerant suction structure according to claim 18,
wherein the switch portion has a flat valve seat surface, the valve
body has a flat seal surface, and the seal surface comes into
surface contact with the valve seat surface in a state in which the
valve body exists at the shutoff position.
20. The refrigerant suction structure according to claim 17,
wherein the introduction passage has an inlet for accepting the
refrigerant from the suction pressure zone, and the inlet of the
introduction passage is positioned in an end surface of the rotary
valve, wherein the outlets of the introduction passage are
positioned in a peripheral surface of the rotary valve, wherein a
rotation axis of the rotary valve intersects the end surface,
wherein the refrigerant suction structure comprises: a valve
accommodation chamber rotatably accommodating the rotary valve; and
a guide cylinder surrounding the rotation axis outside the valve
accommodation chamber, wherein a cylinder interior of the guide
cylinder communicates with an inlet of the introduction passage,
wherein the valve body is slidably fitted to the guide cylinder,
the valve body has an internal passage communicating with the
cylinder interior of the guide cylinder, and the internal passage
has an inlet for accepting the refrigerant from the suction
pressure zone, wherein, in the case that the valve body exists at
the shutoff position, the inlet of the internal passage is shut off
by entering the pressure recess, and wherein, in the case that the
valve body exists at the communication position, the inlet of the
internal passage is positioned outside of the pressure recess, so
that the inlet is exposed to the portion of the suction pressure
zone within the compressor.
21. The refrigerant suction structure according to claim 20,
wherein the guide cylinder is formed as an independent body from
members of the compressor other than the valve body, so as to be
allowed to move in a radial direction of the rotary shaft with
respect to the members of the compressor other than the valve
body.
22. The refrigerant suction structure according to claim 14,
wherein the introduction passage has an inlet for accepting the
refrigerant from the suction pressure zone, and the inlet of the
introduction passage is positioned in an end surface of the rotary
valve, wherein the outlets of the introduction passage are
positioned in a peripheral surface of the rotary valve, wherein the
valve body is fitted into the introduction passage from the inlet
of the introduction passage, and wherein, in the case that the
switch portion is in the shutoff state, the valve body is arranged
in the introduction passage in such a manner as to shut off the
outlets of the introduction passage from the portion of the suction
pressure zone within the compressor.
23. The refrigerant suction structure according to claim 22,
wherein the introduction passage has an in-shaft passage positioned
in the rotary shaft, and the in-shaft passage extends in a
direction of a rotation axis of the rotary shaft, wherein the
outlets of the introduction passage extends through a peripheral
surface of the rotary shaft so as to communicate with the in-shaft
passage, wherein the valve body is fitted into the in-shaft passage
in such a manner as to be slidable in a direction of the rotation
axis within the introduction passage, wherein the valve body is
moved in the direction of the rotation axis within the in-shaft
passage, so as to be switched between the communication position
and the shutoff position, and wherein the valve body at the shutoff
position shuts off the outlets of the introduction passage with
respect to the in-shaft passage.
24. The refrigerant suction structure according to claim 14,
wherein the compressor comprises: a cylinder block having the
cylinder bores; and a rear housing member coupled to the cylinder
block, and wherein the rear housing member has in it a suction
chamber, and the valve body is arranged within the rear housing
member.
25. An operation control method in a fixed displacement type piston
compressor, wherein the compressor comprises: a rotary shaft
coupled to an external drive source via a clutch; a plurality of
cylinder bores arranged around the rotary shaft; a plurality of
pistons defining compression chambers in the cylinder bores by
being respectively accommodated in the cylinder bores; a cam body
integrated with the rotary shaft, the cam body converting a
rotation of the rotary shaft into reciprocation of each of the
pistons; a suction pressure zone; a rotary valve having an
introduction passage for introducing a refrigerant from the suction
pressure zone to each of the compression chambers; and a discharge
pressure zone, wherein the rotary valves integrally rotate with the
rotary shaft, wherein the suction pressure zone has a portion
within the compressor, wherein the introduction passage has outlets
for feeding out the refrigerant toward each of the compressors,
wherein the operation control method comprises: preparing a switch
portion capable of being switched between a communication state and
a shutoff state, wherein the switch portion in the communication
state allows the portion of the suction pressure zone within the
compressor to communicate with the outlets of the introduction
passage, the switch portion in the shutoff state shuts off the
portion of the suction pressure zone within the compressor from the
outlets of the introduction passage, the switch portion is provided
with a valve body, a working pressure chamber, and a working
pressure applying portion, wherein the valve body is capable being
switched between a communication position allowing the portion of
the suction pressure zone within the compressor to communicate with
the outlet of the introduction passage, and a shutoff position
shutting off the portion of the suction pressure zone within the
compressor from the outlets of the introduction passage, wherein
the working pressure chamber introduces a working pressure applied
to the valve body to arrange the valve body at the communication
position, wherein the working pressure applying portion applies the
working pressure to the working pressure chamber, and wherein the
working pressure applying portion is provided with a switch valve
that is switched between a first state, in which the refrigerant in
the discharge pressure zone can be fed to the working pressure
chamber and a second state, in which the refrigerant in the
discharge pressure chamber cannot be fed to the working pressure
chamber; setting the clutch to a coupled state after setting the
switch valve to the second state, at a time of switching the clutch
from the shutoff state to the coupled state; and switching the
switch valve to the first state after setting the clutch to the
coupled state.
26. The operation control method according to claim 25, wherein the
clutch is an electromagnetic clutch which, when magnetized, comes
to the coupled state coupling the rotary shaft to the external
driving source, and wherein the operation control method comprises:
gradually increasing an electric current fed to the electromagnetic
clutch to magnetize the electromagnetic clutch, at a time of
switching the electromagnetic clutch from a demagnetized state to a
magnetized state; and switching the switch valve from the second
state to the first state after a value of the electric current
becomes maximum.
27. An operation control method in a fixed displacement type piston
compressor, wherein the compressor comprises: a rotary shaft
coupled to an external drive source via a clutch; a plurality of
cylinder bores arranged around the rotary shaft; a plurality of
pistons defining compression chambers in the cylinder bores by
being respectively accommodated in the cylinder bores; a cam body
integrated with the rotary shaft, the cam body converting a
rotation of the rotary shaft into reciprocation of each of the
pistons; a suction pressure zone; a rotary valve having an
introduction passage for introducing a refrigerant from the suction
pressure zone to each of the compression chambers, the rotary valve
integrally rotating with the rotary shaft, the suction pressure
zone having a portion within the compressor, and the introduction
passage having outlets for feeding out the refrigerant toward each
of the compression chambers, wherein the operation control method
comprises: preparing a switch portion capable of being switched
between a communication state and a shutoff state, wherein the
switch portion in the communication state allows the portion of the
suction pressure zone within the compressor to communicate with the
outlets of the introduction passage, the switch portion in the
shutoff state shuts off the portion of the suction pressure zone
within the compressor from the outlets of the introduction passage,
the switch portion is provided with a valve body and an
electromagnetic driving portion, wherein the valve body is capable
being switched between a communication position allowing the
portion of the suction pressure zone within the compressor to
communicate with the outlets of the introduction passage, and a
shutoff position shutting off the portion of the suction pressure
zone within the compressor from the outlets of the introduction
passage, wherein the electromagnetic driving portion is capable of
driving the valve body on the basis of an electromagnetic force,
and the electromagnetic driving portion is capable of switching the
valve body between a first state, in which the valve body is
arranged at the communication position, and a second state, in
which the valve body is arranged at the shutoff position; wherein
the operation control method comprises: setting the clutch to the
coupled state after setting the electromagnetic driving portion to
the second state, at a time of switching the clutch from the
shutoff state to the coupled state; and setting the electromagnetic
driving portion to the first state after setting the clutch to the
coupled state.
28. The operation control method according to claim 27, wherein the
clutch is an electromagnetic clutch which, when magnetized, comes
to the coupled state coupling the rotary shaft to the external
driving source, and wherein the operation control method comprises:
gradually increasing an electric current fed to the electromagnetic
clutch to magnetize the electromagnetic clutch, at a time of
switching the electromagnetic clutch from a demagnetized state to a
magnetized state; and demagnetizing the electromagnetic driving
portion after a value of the electric current becomes maximum.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a refrigerant suction
structure in a fixed displacement type piston compressor provided
with a rotary valve. The piston defines a compression chamber
within a cylinder bore. The rotary valve has an introduction
passage for introducing refrigerant from a suction pressure zone to
the compression chamber. The rotary valve integrally rotates with a
rotary shaft. Further, the present invention relates to an
operation control method in the fixed displacement type piston
compressor.
[0002] Japanese Laid-Open Patent Publication Nos. 7-119631 and
2006-83835 each disclose a piston compressor using a rotary valve.
Japanese Laid-Open Patent Publication Nos. 64-88064 and 2000-145629
each disclose a piston compressor using a reed valve type suction
valve. The piston compressor using the rotary valve has a less
suction resistance at a time of drawing suction gas into a cylinder
bore and is excellent in an energy efficiency in comparison with
the piston compressor using the reed type suction valve.
[0003] Japanese Laid-Open Patent Publication No. 7-119631 discloses
a starting impact which may be generated at a time of starting a
compressor. If torque is rapidly increased in accordance with
compression of gas at a time of starting the compressor, a load is
applied to an internal combustion engine, which serves as a vehicle
engine. As a result, a traveling speed of the vehicle may be
lowered for a moment. In this case, a vehicle occupant feels a
shock.
[0004] The rotary valve in Japanese Laid-Open Patent Publication
No. 7-119631 can be moved in an axial direction of a rotary shaft
in correspondence to a pressure in a control pressure chamber. The
compressor has a suction port, which is a suction pressure zone
positioned in a center portion of a cylinder block. The rotary
valve has a bypass groove which can connect the cylinder bore with
the suction port. The rotary valve is moved in the axial direction
in such a manner that the bypass groove connects almost all the
cylinder bores with the suction port at a time when the operation
of the compressor is stopped and when the compressor is started.
Accordingly, even if the piston actuates so as to compress the gas
within the cylinder bore at a time of starting the compressor, the
gas within the cylinder bore flows to the suction port via the
bypass groove. As a result, the starting impact is suppressed.
[0005] It is necessary to minimize a clearance in a peripheral
surface of the rotary valve, so that the gas does not leak along a
peripheral surface of the rotary valve, and that the rotary valve
can be rotated. Further, it is necessary that the clearance allows
the rotary valve to move in the axial direction. However, it is
very difficult to control the clearance mentioned above.
[0006] The piston compressor in Japanese Laid-Open Patent
Publication No. 2000-145629 has a differential pressure sensitive
on-off valve which is opened and closed on the basis of a
differential pressure between a discharge pressure and a suction
pressure. The differential pressure sensitive on-off valve is
arranged between a low pressure refrigerant conduit introducing the
refrigerant to the compressor from the outside of the compressor,
and a suction chamber positioned within the compressor. If the
compressor is started from a pressure balanced state, the
differential pressure sensitive on-off valve comes to a closed
state, and stops an inflow of the refrigerant from the outside of
the compressor to the suction chamber. As a result, the starting
impact is reduced.
[0007] However, even if the differential pressure sensitive on-off
valve comes to the closed state, the refrigerant is left in the
suction chamber, and the residual refrigerant is drawn to the
cylinder bore so as to be compressed. Since the volumetric capacity
of the suction chamber is large so as to suppress a suction
pulsation of the compressor, the amount of the refrigerant drawn
into the cylinder bore in a state in which the differential
pressure sensitive on-off valve is closed is large. Accordingly,
the effect of reducing the starting impact obtained by the
differential pressure sensitive on-off valve is not sufficient.
SUMMARY OF THE INVENTION
[0008] An objective of the present invention is to improve the
effect of reducing the starting impact.
[0009] According to one aspect of the invention, a refrigerant
suction structure in a fixed displacement type piston compressor is
provided. The compressor includes a rotary shaft coupled to an
external drive source via a clutch. A plurality of cylinder bores
are arranged around the rotary shaft. A plurality of pistons define
compression chambers in the cylinder bores by being respectively
accommodated in the cylinder bores. A cam body is integrated with
the rotary shaft. The cam body converts a rotation of the rotary
shaft into reciprocation of each of the pistons. A rotary valve has
an introduction passage for introducing a refrigerant from a
suction pressure zone to each of the compression chambers. The
rotary valve integrally rotates with the rotary shaft. The suction
pressure zone has a portion within the compressor. The introduction
passage has outlets for feeding out the refrigerant toward each of
the compression chambers. The refrigerant suction structure has a
switch portion capable of being switched between a communication
state and a shutoff state. The switch portion in the communication
state allows the portion of the suction pressure zone within the
compressor to communicate with the outlets of the introduction
passage. The switch portion in the shutoff state shuts off the
portion of the suction pressure zone within the compressor from the
outlets of the introduction passage. The switch portion includes a
valve body, a working pressure chamber, and a working pressure
applying portion. The valve body is capable of being switched
between a communication position and a shutoff position. The valve
body in the communication position allows the portion of the
suction pressure zone within the compressor to communicate with the
outlets of the introduction passage. The valve body in the shutoff
position shuts off the portion of the suction pressure zone within
the compressor from the outlets of the introduction passage. The
working pressure chamber introduces a working pressure that is
applied to the valve body so as to arrange the valve body at the
communication position. The working pressure applying portion
applies the working pressure to the working pressure chamber. The
pressure in the suction pressure zone acts against the pressure in
the working pressure chamber through the valve body.
[0010] Further, according to another aspect of the invention, a
refrigerant suction structure in a fixed displacement type piston
compressor is provided. The refrigerant suction structure has a
switch portion capable of being switched between a communication
state and a shutoff state. The switch portion in the communication
state allows the portion of the suction pressure zone within the
compressor to communicate with the outlets of the introduction
passage. The switch portion in the shutoff state shuts off the
portion of the suction pressure zone within the compressor from the
outlets of the introduction passage. The switch portion includes a
valve body capable of being switched between a communication
position and a shutoff position. The valve body in the
communication position allows the portion of the suction pressure
zone within the compressor to communicate with the outlets of the
introduction passage. The valve body in the shutoff position shuts
off the portion of the suction pressure zone within the compressor
from the outlets of the introduction passage. An electromagnetic
driving portion drives the valve body on the basis of an
electromagnetic force.
[0011] Further, another aspect of the invention, an operation
control method in a fixed displacement type piston compressor is
provided. The operation control method includes preparing a switch
portion capable of being switched between a communication state and
a shutoff state. The switch portion in the communication state
allows the portion of the suction pressure zone within the
compressor to communicate with the outlets of the introduction
passage. The switch portion in the shutoff state shuts off the
portion of the suction pressure zone within the compressor from the
outlets of the introduction passage. The switch portion is provided
with a valve body, a working pressure chamber, and a working
pressure applying portion. The valve body is capable being switched
between a communication position allowing the portion of the
suction pressure zone within the compressor to communicate with the
outlet of the introduction passage, and a shutoff position shutting
off the portion of the suction pressure zone within the compressor
from the outlets of the introduction passage. The working pressure
chamber introduces a working pressure applied to the valve body to
arrange the valve body at the communication position. The working
pressure applying portion applies the working pressure to the
working pressure chamber. The working pressure applying portion is
provided with a switch valve that is switched between a first
state, in which the refrigerant in the discharge pressure zone can
be fed to the working pressure chamber and a second state, in which
the refrigerant in the discharge pressure chamber cannot be fed to
the working pressure chamber. The operation control method further
includes setting the clutch to a coupled state after setting the
switch valve to the second state, at a time of switching the clutch
from the shutoff state to the coupled state. The operation control
method further includes switching the switch valve to the first
state after setting the clutch to the coupled state.
[0012] Further, according to another aspect of the invention, an
operation control method in a fixed displacement type piston
compressor is provided. The operation control method includes
preparing a switch portion capable of being switched between a
communication state and a shutoff state. The switch portion in the
communication state allows the portion of the suction pressure zone
within the compressor to communicate with the outlets of the
introduction passage. The switch portion in the shutoff state shuts
off the portion of the suction pressure zone within the compressor
from the outlets of the introduction passage. The switch portion is
provided with a valve body and an electromagnetic driving portion.
The valve body is capable being switched between a communication
position allowing the portion of the suction pressure zone within
the compressor to communicate with the outlets of the introduction
passage, and a shutoff position shutting off the portion of the
suction pressure zone within the compressor from the outlets of the
introduction passage. The electromagnetic driving portion is
capable of driving the valve body on the basis of an
electromagnetic force. The electromagnetic driving portion is
capable of switching the valve body between a first state, in which
the valve body is arranged at the communication position, and a
second state, in which the valve body is arranged at the shutoff
position. The operation control method further includes setting the
clutch to the coupled state after setting the electromagnetic
driving portion to the second state, at a time of switching the
clutch from the shutoff state to the coupled state. The operation
control method further includes setting the electromagnetic driving
portion to the first state after setting the clutch to the coupled
state.
[0013] Other aspects and advantages of the invention will become
apparent from the following description, taken in conjunction with
the accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The features of the present invention that are believed to
be novel are set forth with particularity in the appended claims.
The invention, together with objects and advantages thereof, may
best be understood by reference to the following description of the
presently preferred embodiments together with the accompanying
drawings in which:
[0015] FIG. 1 is a side cross-sectional view of a whole of a
compressor, showing a first embodiment;
[0016] FIG. 2A is a cross-sectional view taken along line 2A-2A in
FIG. 1;
[0017] FIG. 2B is a cross-sectional view taken along line 2B-2B in
FIG. 1;
[0018] FIG. 3 is a partial enlarged view of FIG. 1;
[0019] FIG. 4 is an enlarged view showing a state in which the
valve body is moved from the position shown in FIG. 3;
[0020] FIG. 5 is a flowchart showing an operation control program
of the compressor in FIG. 1;
[0021] FIG. 6 is a timing chart showing a torque fluctuation in
accordance with a program in FIG. 5;
[0022] FIG. 7 is a timing chart showing a second embodiment;
[0023] FIG. 8 is a side cross-sectional view of a whole of a
compressor in accordance with a third embodiment;
[0024] FIG. 9A is a partial enlarged view showing a state in which
the electromagnetic valve is switched from the state shown in FIG.
8;
[0025] FIG. 9B is a timing chart of the compressor in FIG. 8;
[0026] FIG. 10 is a partial enlarged side cross-sectional view of a
compressor in accordance with a fourth embodiment;
[0027] FIG. 11A is a cross-sectional view showing a state in which
the electromagnetic valve is switched from the state shown in FIG.
10;
[0028] FIG. 11B is a timing chart of the compressor in FIG. 10;
[0029] FIG. 12A is a partial enlarged side cross-sectional view of
a compressor in accordance with a fifth embodiment;
[0030] FIG. 12B is a cross-sectional view showing a state in which
the electromagnetic valve is switched from the state shown in FIG.
12A;
[0031] FIG. 13 is a side cross-sectional view of a whole of a
compressor in accordance with a sixth embodiment;
[0032] FIG. 14 is a cross-sectional view showing a state in which
the electromagnetic valve is switched from the state shown in FIG.
13;
[0033] FIG. 15A is a partial enlarged side cross-sectional view of
a compressor in accordance with a seventh embodiment;
[0034] FIG. 15B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 15A;
[0035] FIG. 16A is a partial enlarged side cross-sectional view of
a compressor in accordance with an eighth embodiment;
[0036] FIG. 16B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 16A;
[0037] FIG. 17 is a side cross-sectional view of a whole of a
compressor in accordance with a ninth embodiment;
[0038] FIG. 18A is a partial enlarged view of FIG. 17;
[0039] FIG. 18B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 18A;
[0040] FIG. 19A is a partial enlarged side cross-sectional view of
a compressor in accordance with a tenth embodiment;
[0041] FIG. 19B is a cross-sectional view showing a state in which
the electromagnetic valve is switched from the state shown in FIG.
19A;
[0042] FIG. 20 is a side cross-sectional view of a whole of a
one-headed piston compressor in accordance with an eleventh
embodiment;
[0043] FIG. 21 is a side cross-sectional view of a whole of a
compressor in accordance with a twelfth embodiment;
[0044] FIG. 22A is a cross-sectional view taken along line 22A-22A
in FIG. 21;
[0045] FIG. 22B is a cross-sectional view taken along line 22B-22B
in FIG. 21;
[0046] FIG. 23 is a partial enlarged cross-sectional view of FIG.
21;
[0047] FIG. 24 is an enlarged view showing a state in which the
valve body is moved from the position shown in FIG. 23;
[0048] FIG. 25 is a flowchart showing an operation control program
of the compressor in FIG. 21;
[0049] FIG. 26 is a timing chart showing a torque fluctuation in
accordance with a program in FIG. 25;
[0050] FIG. 27 is a timing chart showing a thirteenth
embodiment;
[0051] FIG. 28A is a partial enlarged cross-sectional view of a
compressor in accordance with a fourteenth embodiment;
[0052] FIG. 28B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 28A;
[0053] FIG. 29A is a partial enlarged cross-sectional view of a
compressor in accordance with a fifteenth embodiment;
[0054] FIG. 29B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 29A;
[0055] FIG. 30A is a partial enlarged cross-sectional view of a
compressor in accordance with a sixteenth embodiment;
[0056] FIG. 30B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 30A;
[0057] FIG. 31A is a partial enlarged side cross-sectional view of
a compressor in accordance with a seventeenth embodiment;
[0058] FIG. 31B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 31A;
[0059] FIG. 32A is a partial enlarged side cross-sectional view of
a compressor in accordance with an eighteenth embodiment;
[0060] FIG. 32B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 32A;
[0061] FIG. 33A is a partial enlarged side cross-sectional view of
a compressor in accordance with a nineteenth embodiment;
[0062] FIG. 33B is a cross-sectional view showing a state in which
the valve body is moved from the position shown in FIG. 33A;
and
[0063] FIG. 34 is a side cross-sectional view of a whole of a
compressor in accordance with a twentieth embodiment.
DETAILED DESCRIPTION OF PREFERABLE EMBODIMENTS
[0064] FIGS. 1 to 6 show a fixed displacement type piston
compressor 10 in accordance with a first embodiment obtained by
embodying the present invention.
[0065] As shown in FIG. 1, a front cylinder block 11 is coupled to
a rear cylinder block 12. A front housing member 13 is coupled to
the front cylinder block 11, and a rear housing member 14 is
coupled to the rear cylinder block 12. The front cylinder block 11,
the rear cylinder block 12, the front housing member 13 and the
rear housing member 14 construct a whole housing of the compressor
10.
[0066] A front discharge chamber 131 is formed in the front housing
member 13. A rear discharge chamber 141 and a suction chamber 142
are formed in the rear housing member 14. Each of the front
discharge chamber 131 and the rear discharge chamber 141 is a
portion of a discharge pressure zone within the compressor 10. The
suction chamber 142 is a portion of a suction pressure zone within
the compressor 10. The inside of the compressor refers to the
inside of the entire housing of the compressor 10, and the outside
of the compressor refers to the outside of the entire housing of
the compressor 10.
[0067] As shown in FIG. 1, a valve plate 15, a valve forming plate
16, and a retainer forming plate 17 are arranged between the front
cylinder block 11 and the front housing member 13. A valve plate
18, a valve forming plate 19, and a retainer forming plate 20 are
formed between the rear cylinder block 12 and the rear housing
member 14. Discharge ports 151 and 181 are formed respectively in
the valve plates 15 and 18, and discharge valves 161 and 191 are
formed respectively in the valve forming plates 16 and 19. The
discharge valves 161 and 191 respectively open and close the
discharge ports 151 and 181. Retainers 171 and 201 are formed
respectively in the retainer forming plates 17 and 20. The retainer
171 and 201 limit opening degrees of the discharge valves 161 and
191.
[0068] As shown in FIG. 1, a rotary shaft 21 is rotatably supported
to the front cylinder block 11 and the rear cylinder block 12. A
front shaft hole 111 and a rear shaft hole 121 extend through the
front cylinder block 11 and the rear cylinder block 12,
respectively, and the rotary shaft 21 is put through the front
shaft hole 111 and the rear shaft hole 121. An outer peripheral
surface of the rotary shaft 21 comes into contact with an inner
peripheral surface of the front shaft hole 111 and the rear shaft
hole 121, and the rotary shaft 21 is directly supported by the
front cylinder block 11 and the rear cylinder block 12 at the inner
peripheral surface of the front shaft hole 111 and the rear shaft
hole 121. An outer peripheral surface portion of the rotary shaft
21 which comes into contact with the front shaft hole 111 is a
front seal peripheral surface 211, and an outer peripheral surface
portion of the rotary shaft 21 which comes into contact with the
rear shaft hole 121 is a rear seal peripheral surface 212.
[0069] A swash plate 23, which serves as a cam body, is firmly
attached to the rotary shaft 21. The swash plate 23 is accommodated
in a swash plate chamber 24 defined by the front cylinder block 11
and the rear cylinder block 12. A lip seal type shaft seal member
22 is arranged between the front housing member 13 and the rotary
shaft 21. The shaft seal member 22 prevents a gas leakage through
clearance between the front housing member 13 and the rotary shaft
21. A protruding end portion of the rotary shaft 21 protruding to
the outside from the front housing member 13 is connected to a
vehicle engine 26, which is an external drive source, via an
electromagnetic clutch 25. The rotary shaft 21 obtains a rotary
driving force from the vehicle engine 26 via the electromagnetic
clutch 25.
[0070] As shown in FIG. 2A, a plurality of front cylinder bores 27
are formed in the front cylinder block 11 so as to be arranged
around the rotary shaft 21. As shown in FIG. 2B, a plurality of
rear cylinder bores 28 are formed in the rear cylinder block 12 so
as to be arranged around the rotary shaft 21. Double headed pistons
29 are accommodated respectively in the front cylinder bore 27 and
the rear cylinder bore 28 forming a pair back and force.
[0071] As shown in FIG. 1, a rotational motion of the swash plate
23 integrally rotating with the rotary shaft 21 is transmitted to
the double headed pistons 29 via shoes 30, and each double headed
piston 29 reciprocates back and forth within the front cylinder
bore 27 and the rear cylinder bore 28. Each double headed piston 29
defines a front compression chamber 271 within the front cylinder
bore 27, and defines a rear compression chamber 281 within the rear
cylinder bore 28.
[0072] As shown in FIG. 1, the rotary shaft 21 has in it an
in-shaft passage 31 extending along a rotation axis 210 of the
rotary shaft 21. An inlet 311 of the in-shaft passage 31 is
positioned in a rear end surface of the rotary shaft 21, and is
open to the suction chamber 142. The in-shaft passage 31 has a
front outlet 312 and a rear outlet 313. The front outlet 312 is
open to a front seal peripheral surface 211 of the rotary shaft 21.
The rear outlet 313 is open to a rear seal peripheral surface
212.
[0073] As shown in FIG. 2A, the front cylinder block 11 has the
same number of front communication passages 32 as that of the front
cylinder bores 27. Each of the front communication passages 32
connect each of the front cylinder bores 27 with the front shaft
hole 111. As shown in FIG. 2B, the rear cylinder block 12 has the
same number of rear communication passages 33 as that of the rear
cylinder bores 28. Each of the rear communication passage 33
communicates each of the rear cylinder bores 28 with the rear shaft
hole 121. In accordance with the rotation of the rotary shaft 21,
the front outlet 312 of the in-shaft passage 31 intermittently
communicates with each of the front communication passage 32, and
the rear outlet 313 intermittently communicates with each of the
rear communication passage 33.
[0074] In FIG. 1, in the case of a stroke in which the double
headed piston 29 moves from a left side to a right side, that is,
in the case of a state in which the double headed piston 29 sets a
certain front cylinder bore 27 to a suction stroke, the front
outlet 312 communicates the corresponding front communication
passage 32. As a result, a refrigerant within the in-shaft passage
31 of the rotary shaft 21 is drawn into the corresponding front
compression chamber 271 via the front outlet 312, and the
corresponding front communication passage 32.
[0075] In FIG. 1, in the case of a stroke in which the double
headed piston 29 moves from the right side to the left side, that
is, in the case of a state in which the double headed piston 29
sets a certain front cylinder bore 27 to a discharge stroke, the
front seal peripheral surface 211 shuts off the front outlet 312
from the corresponding front communication passage 32. As a result,
the refrigerant within the front compression chamber 271 is
discharged to the front discharge chamber 131 while pushing the
discharge valve 161 from the discharge port 151. The refrigerant
discharged to the front discharge chamber 131 flows out to an
external refrigerant circuit 34 via a discharge passage 341.
[0076] In FIG. 1, in the case of a stroke in which the double
headed piston 29 moved from the right side to the left side, that
is, in the case of a state in which the double headed piston 29
sets a certain rear cylinder bore 28 to a suction stroke, the rear
outlet 313 communicates with the corresponding rear communication
passage 33. As a result, the refrigerant within the in-shaft
passage 31 of the rotary shaft 21 is drawn into the corresponding
rear compression chamber 281 via the rear outlet 313 and the
corresponding rear communication passage 33.
[0077] In FIG. 1, in the case of a stroke in which the double
headed piston 29 moves from the left side to the right side, that
is, in the case of a state in which the double headed piston 29
sets a certain rear cylinder bore 28 to a discharge stroke, the
rear seal peripheral surface 212 shuts off the rear outlet 313 from
the corresponding rear communication passage 33. As a result, the
refrigerant within the rear compression chamber 281 is discharged
to the rear discharge chamber 141 while pushing the discharge valve
191 from the discharge port 181. The refrigerant discharged to the
rear discharge chamber 141 flows out to the external refrigerant
circuit 34 via a discharge passage 343.
[0078] As shown in FIG. 1, a heat exchanger 37, an expansion valve
38, and a heat exchanger 39 are arranged in the external
refrigerant circuit 34. The heat exchanger 37 absorbs heat from the
refrigerant. The expansion valve 38 controls the flow rate of the
refrigerant in correspondence to a fluctuation of a gas temperature
measured in an outlet of the heat exchanger 39. The heat exchanger
39 transfers the peripheral heat to the refrigerant. The
refrigerant flowing out to the external refrigerant circuit 34
flows back to the suction chamber 142.
[0079] As shown in FIG. 1, a portion of the front seal peripheral
surface 211 of the rotary shaft 21 serves as a first rotary valve
35. A portion of the rear seal peripheral surface 212 of the rotary
shaft 21 serves as a second rotary valve 36. In other words, the
rotary shaft 21 is a rotary valve. Each of the first rotary valve
35 and the second rotary valve 36 is integrally formed in the
rotary shaft 21. The rotation axis 210 of the rotary shaft 21 is a
rotation axis of the first rotary valve 35, and also is a rotation
axis of the second rotary valve 36.
[0080] As shown in FIG. 1, a rear end surface of the rotary shaft
21, that is, a rear end surface of the second rotary valve 36
intersects the rotation axis 210 of the rotary valve. The in-shaft
passage 31 and the front outlet 312 construct an introduction
passage of the first rotary valve 35. The in-shaft passage 31 and
the rear outlet 313 construct an introduction passage of the second
rotary valve 36. The front shaft hole 111 is a first valve
accommodation chamber accommodating the first rotary valve 35. The
rear shaft hole 121 is a second valve accommodation chamber
accommodating the second rotary valve 36.
[0081] As shown in FIGS. 3 and 4, the rear housing member 14 has an
end wall 40 forming the suction chamber 142. A cylinder 41 is
integrally formed in an inner surface of the end wall 40. A
cylinder interior of the cylinder 41 is referred to as a working
pressure recess 411, which serves as a working pressure chamber
forming recess. A spool-shaped valve body 42 is slidably fitted
into the working pressure recess 411. The valve body 42 is provided
with a disc-shaped piston portion 43, and a cylinder portion 44.
The piston portion 43 defines a working pressure chamber 412 within
the working pressure recess 411. A pressure within the suction
chamber 142, that is, a suction pressure acts against the pressure
within the working pressure chamber 412 through the valve body 42.
A peripheral wall of the cylinder portion 44 has an introduction
port 441. In other words, the introduction port 441 is open to an
outer peripheral surface of the cylinder portion 44, and
communicates with a cylinder interior 442 of the cylinder portion
44. The cylinder interior 442 is an inside passage of the valve
body 42.
[0082] As shown in FIGS. 3 and 4, a guide cylinder 45 is integrally
formed in an end surface of the rear cylinder block 12 in such a
manner as to face the cylinder 41. A cylinder interior 451 of the
guide cylinder 45 communicates with an inlet 311 of an in-shaft
passage 31, which serves as an introduction passage. A distal end
of the guide cylinder 45 is away from a distal end of the cylinder
41. The cylinder portion 44 of the valve body 42 is slidably fitted
to the guide cylinder 45. A snap ring 46 is attached to an inner
peripheral surface of the guide cylinder 45, and a first return
spring 47 is arranged between the snap ring 46 and the piston
portion 43. The first return spring 47 urges the valve body 42 in
such a manner that the valve body 42 comes close to the end wall 40
of the rear housing member 14. The closer the valve body 42 to the
end wall 40, the less the volumetric capacity of the working
pressure chamber 412 becomes.
[0083] FIG. 3 shows a state in which the valve body 42 is located
at a communication position in such a manner that the valve body 42
allows the in-shaft passage 31 to communicate with the suction
chamber 142. FIG. 4 shows a state in which the valve body 42 is
located at a shutoff position in such a manner that the valve body
42 shuts off the suction chamber 142 from the in-shaft passage 31.
In other words, in the state shown in FIG. 3, a whole of the
introduction port 441 of the valve body 42 is exposed to the
interior of the suction chamber 142. The in-shaft passage 31
communicates with the suction chamber 142 via the cylinder interior
451 of the guide cylinder 45, the cylinder interior 442 of the
cylinder portion 44, and the introduction port 441. In the state
shown in FIG. 4, a whole of the introduction port 441 enters the
working pressure recess 411. As a result, the cylinder portion 44
of the valve body 42 shuts off the in-shaft passage 31 from the
suction chamber 142.
[0084] As shown in FIGS. 3 and 4, a communication port 401 extends
through the end wall 40 of the rear housing member 14. The
communication port 401 is open to the interior of the working
pressure chamber 412. A feed port 481 of an electromagnetic
three-way valve 48 communicates with the communication port 401 via
a conduit 63. The electromagnetic three-way valve 48 serves as a
switch valve constructing a working pressure applying portion.
[0085] As shown in FIGS. 3 and 4, the electromagnetic three-way
valve 48 has a tubular valve housing 49. The valve housing 49 is
provided with a small-diameter cylindrical portion 491 and a
large-diameter cylindrical portion 492, and a fixed iron core 50 is
accommodated within the small-diameter cylindrical portion 491 in a
fixed manner. A movable iron core 51 is slidably fitted into the
small-diameter cylindrical portion 491. The movable iron core 51
has a flange 511 positioned in the large-diameter cylindrical
portion 492. An urging spring 52 is arranged between a step 493
between the small-diameter cylindrical portion 491 and the
large-diameter cylindrical portion 492, and a flange 511. The
urging spring 52 urges the movable iron core 51 in a direction
moving the movable iron core 51 away from the fixed iron core 50. A
coil 53 is wound around the small-diameter cylindrical portion 491
in such a manner as to overlap both of the fixed iron core 50 and
the movable iron core 51. If an electric current is fed to the coil
53, the fixed iron core 50 is excited so as to attract the movable
iron core 51 against a spring force of the urging spring 52.
[0086] As shown in FIGS. 3 and 4, the movable iron core 51
accommodates in it a first valve body 54. The first valve body 54
faces the fixed iron core 50, and selectively contacts and
separates from the fixed iron core 50. A valve seat 501 is
integrally formed in an end surface of the fixed iron core 50
facing the movable iron core 51. An urging spring 55 urges the
first valve body 54 toward the valve seat 501. The fixed iron core
50 has in it a passage 56. The passage 56 extends through the valve
seat 501. An inlet 561 of the passage 56 communicates with the rear
discharge chamber 141 via a conduit 57.
[0087] As shown in FIGS. 3 and 4, a lid 58 is fitted to the
large-diameter cylindrical portion 492 of the valve housing 49. A
second valve body 60 is fastened to an end surface of the movable
iron core 51 facing the lid 58. The second valve body 60
selectively contacts and separates from the lid 58. A discharge
port 581 extends through the lid 58. The second valve body 60 shuts
off the discharge port 581 from the cylinder interior 494 of the
large-diameter cylindrical portion 492 in the case that the second
valve body 60 comes into contact with the lid 58. The discharge
port 581 communicates with the suction chamber 142 via the conduit
59.
[0088] As shown in FIGS. 3 and 4, a groove 61 is formed in a
peripheral surface of the movable iron core 51. The groove 61
communicates with a space 62 between the fixed iron core 50 and the
movable iron core 51. The cylinder interior 494 of the
large-diameter cylindrical portion 492 communicates with the space
62 via the groove 61. The cylinder interior 494 of the
large-diameter cylindrical portion 492 communicates with the
working pressure chamber 412 via a feed port 481 provided in a
penetrating manner in the large-diameter cylindrical portion 492
and a conduit 63.
[0089] As shown in FIG. 1, a control computer C controls
magnetization and demagnetization of each of the electromagnetic
three-way valve 48 and the electromagnetic clutch 25. An air
conditioner actuating switch 64, a room temperature setting device
65, and a room temperature detector 66 are connected to the control
computer C so that signals can be transmitted therebetween. The
room temperature setting device 65 sets a target room temperature,
and the room temperature detector 66 detects a room temperature. In
the case that the air conditioner actuating switch 64 is in an ON
state, the control computer C controls a current feed, that is, a
magnetization and demagnetization with respect to the
electromagnetic three-way valve 48 and the electromagnetic clutch
25 on the basis of a temperature difference between the target room
temperature and the detected room temperature.
[0090] In the case that the detected temperature is lower than the
target temperature, or in the case that the detected temperature is
higher than the target temperature and the temperature difference
between the detected temperature and the target temperature is
equal to or less than an allowable difference, the control computer
C stops feeding the electric current to the electromagnetic clutch
25. In this case, the electromagnetic clutch 25 comes to a shut-off
state, and a rotational driving force of the vehicle engine 26 is
not transmitted to the rotary shaft 21. Further, in the case that
the detected temperature is higher than the target temperature, and
the temperature difference between the detected temperature and the
target temperature gets over the allowable difference, the control
computer C feeds the electric current to the electromagnetic clutch
25. In this case, the electromagnetic clutch 25 comes to a coupled
state, and the rotational driving force of the vehicle engine 26 is
transmitted to the rotary shaft 21.
[0091] A timing chart in FIG. 6 shows a clutch waveform K1, a
three-way valve waveform V and a torque waveform T1. The clutch
waveform K1 indicates a feed timing of the electric current with
respect to the electromagnetic clutch 25. The clutch waveform K1
indicates a clutch starting time t1, which is a time for starting a
current application to the electromagnetic clutch 25, and a clutch
ending time t2, which is a time for finishing the current
application to the electromagnetic clutch 25. The three-way valve
waveform V indicates a feed timing of the electric current to the
electromagnetic three-way valve 48. The three-way valve waveform V
has a first exciting period section V1 set in correspondence to the
clutch starting time t1, and a second exciting period section V2
set in correspondence to the clutch ending time t2. A starting time
t3 of the first exciting period section V1 is before the clutch
starting time t1, and an ending time t4 of the first exciting
period section V1 is after the clutch starting time t1. In other
words, the control computer C first carries out the current feed to
the electromagnetic three-way valve 48 and thereafter carries out
the current feed to the electromagnetic clutch 25, at a time of
starting the current feed to the electromagnetic clutch 25. A
starting time t5 of the second exciting period section V2 is before
the clutch ending time t2, and the ending time of the second
exciting period section V2 is identical with the clutch ending time
t2.
[0092] FIG. 5 is a flowchart showing an operation control program
for controlling an operation of the compressor 10. The control
computer C controls the operation of the compressor 10 on the basis
of an operation control program shown by the flowchart. A
description will be given below of the operation control of the
compressor 10 in accordance with the operation control program
shown by the flowchart.
[0093] It is assumed that the compressor 10 is in an operation stop
state (a state in which the electromagnetic clutch 25 is shut off),
and the electromagnetic three-way valve 48 is in a demagnetized
state (a state in which the current application is stopped). In a
state in which the electromagnetic three-way valve 48 is
demagnetized, the first valve body 54 is away from the valve seat
501 and the second valve body 60 closes the discharge port 581, as
shown in FIG. 3. In the case that the interior of the working
pressure chamber 412 comes to a pressure corresponding to the
discharge pressure, the valve body 42 exists at a communication
position shown in FIG. 3. However, in the case that the interior of
the working pressure chamber 412 comes to a pressure corresponding
to the suction pressure, the valve body 42 exists at a shut-off
position shown in FIG. 4.
[0094] In step S1, the control computer C determines on the basis
of a comparison between the detected temperature and the target
temperature whether a compressor operation starting mode (a mode
for starting the current application to the electromagnetic clutch
25) is established. In the case of YES in step S1, that is, in the
case that the compressor operation starting mode is established,
the control computer C starts the current application to the
electromagnetic three-way valve 48 in step S2. If the electric
current is fed to the electromagnetic three-way valve 48, the first
valve body 54 comes into contact with the valve seat 501 and the
passage 56 is closed, as shown in FIG. 4. Further, the second valve
body 60 is away from the lid 58 and the discharge port 581 is
opened. In this state, the working pressure chamber 412
communicates with the suction chamber 142 via the discharge passage
constituted by the communication port 401, the conduit 63, the feed
port 481, the cylinder interior 494, the discharge port 581 and the
conduit 59. Accordingly, the interior of the working pressure
chamber 412 becomes the same pressure zone as the interior of the
suction chamber 142. Therefore, the valve body 42 is securely
arranged at the shutoff position shown in FIG. 4 on the basis of a
spring force of the first return spring 47, and the communication
between the introduction port 441 and the suction chamber 142 is
shut off.
[0095] In step S3, the control computer C determines whether a
period ta [(t1-t3)=ta in the case illustrated in FIG. 6] has
elapsed from the start of the current application to the
electromagnetic three-way valve 48. In the case of YES in step S3,
that is, in the case that the period ta has elapsed from the start
of the current application to the electromagnetic three-way valve
48, the control computer C starts the current application to the
electromagnetic clutch 25 in step S4. Accordingly, the
electromagnetic clutch 25 gives way to the coupled state from the
shutoff state, and the rotary shaft 21 and the swash plate 23 start
rotating.
[0096] In step S5, the control computer C determines whether a
period tb [(t4-t1)=tb in the case illustrated in FIG. 6] has
elapsed from the start of the current application to the
electromagnetic clutch 25. In the case of YES in step S5, that is,
in the case that the period tb has elapsed from the start of the
current application to the electromagnetic clutch 25, the control
computer C stops the current application to the electromagnetic
three-way valve 48 in step S6. If the current feed to the
electromagnetic three-way valve 48 is stopped, the first valve body
54 is away from the valve seat 501 and the passage 56 is opened, as
shown in FIG. 3. Further, the second valve body 60 comes into
contact with the lid 58 and the discharge port 581 is closed. In
this state, the communication between the suction chamber 142 and
the working pressure chamber 412 is shut off. The working pressure
chamber 412 communicates with the rear discharge chamber 141 via
the feed passage constituted by the communication port 401, the
conduit 63, the feed port 481, the cylinder interior 494, the
groove 61, the space 62, the passage 56 and the conduit 57.
Accordingly, the refrigerant pressure (the discharge pressure)
within the rear discharge chamber 141 is introduced to the working
pressure chamber 412, and the interior of the working pressure
chamber 412 becomes same pressure zone as the interior of the rear
discharge chamber 141. The communication port 401 and the conduit
63 which is a common passage connecting the working pressure
chamber 412 to the electromagnetic three-way valve 48.
[0097] The pressure (the working pressure) of the refrigerant
within the rear discharge chamber 141 is higher than the pressure
within the cylinder interior 442, and the pressure within the
working pressure chamber 412 arranges the valve body 42 at the
communication position shown in FIG. 3 against the pressure of the
cylinder interior 442 and the spring force of the first return
spring 47. Accordingly, the introduction port 441 is exposed into
the suction chamber 142, and the introduction port 441 communicates
with the suction chamber 142. Therefore, the refrigerant within the
suction chamber 142 flows into the in-shaft passage 31 via the
introduction port 441.
[0098] After stopping the current application to the
electromagnetic three-way valve 48, the computer C determines on
the basis of the comparison between the detected temperature and
the target temperature whether a compressor operation stopping mode
(a mode for stopping the current application to the electromagnetic
clutch 25) is established, in step S7. In the case of YES in step
S7, that is, in the case that the compressor operation stopping
mode is established, the control computer C starts the current
application to the electromagnetic three-way valve 48 in step S8.
If the current application to the electromagnetic three-way valve
48 is started, the communication between the working pressure
chamber 412 and the rear discharge chamber 141 is shut off, and the
working pressure chamber 412 communicates with the suction chamber
142. In other words, the working pressure corresponding to the
discharge pressure within the working pressure chamber 412 is
discharged to the suction chamber 142. In other words, the working
pressure within the working pressure chamber 412 is released.
[0099] In step S9, the control computer C determines whether a
period tc [(t2-t5)=tc in the case illustrated in FIG. 6] has
elapsed from the start of the current application to the
electromagnetic three-way valve 48. In the case of YES in step S9,
that is, in the case that the period tc has elapsed from the start
of the current application to the electromagnetic three-way valve
48, the control computer C stops the current application to the
electromagnetic three-way valve 48 and the electromagnetic clutch
25 in step S10. After the process of step S10, the control computer
C gives way to step S1.
[0100] The torque waveform T1 in FIG. 6 is one example of the
torque fluctuation. In the case that the current application to the
electromagnetic clutch 25 is started, the torque is fluctuated. The
present embodiment excites the electromagnetic three-way valve 48
before starting the current application to the electromagnetic
clutch 25, and stops the current application to the electromagnetic
three-way valve 48 after starting exciting the electromagnetic
clutch 25, at a time of starting the current application to the
electromagnetic clutch 25. As a result, a rapid torque fluctuation
[a fluctuation portion T11 in the torque waveform T1] at a time
when the current application to the electromagnetic clutch 25 is
started is suppressed. Further, even when the current application
to the electromagnetic clutch 25 is stopped, the torque is
fluctuated. The present embodiment excites the electromagnetic
three-way valve 48 before stopping the current application to the
electromagnetic clutch 25, at a time of stopping the current
application to the electromagnetic clutch 25. As a result, the
rapid torque fluctuation at a time when the current application to
the electromagnetic clutch 25 is stopped is suppressed.
[0101] The electromagnetic three-way valve 48, the working pressure
chamber 412 and the valve body 42 construct a switch portion. The
switch portion is capable of switching the suction chamber 142,
which is a portion of the suction pressure zone within the
compressor 10, to a state in which the suction chamber 142
communicates with the front outlet 312 and the rear outlet 313 of
the in-shaft passage 31, which is an introduction passage, and a
state in which the suction chamber 142 is shut off from the front
outlet 312 and the rear outlet 313. In FIGS. 1 and 3, the
electromagnetic three-way valve 48 is in a first state (a
demagnetized state) in which the three-way valve 48 can feed the
refrigerant in the rear discharge chamber 141, which is a discharge
pressure zone, to the working pressure chamber 412. In FIG. 4, the
electromagnetic three-way valve 48 is in a second state (a
magnetized state) in which the three-way valve 48 can feed the
refrigerant in the rear discharge chamber 141, which is a discharge
pressure zone to the working pressure chamber 412.
[0102] The first embodiment has the following advantages.
[0103] (1) In the state in which the pressure within the rear
discharge chamber 141, which is the working pressure, is not
introduced to the working pressure chamber 412, the valve body 42
is arranged at the shutoff position shown in FIG. 4. If the valve
body 42 is arranged at the shutoff position, the suction chamber
142, which is a suction pressure zone within the compressor 10, is
shut off from the introduction port 441. Since the rotation of the
rotary shaft 21 is started after the valve body 42 is previously
arranged at the shutoff position, at a time when the operation of
the compressor 10 is started (at a time when the rotation of the
rotary shaft 21 is started), the refrigerant does not flow in the
cylinder interior 442 and the in-shaft passage 31 from the suction
chamber 142. Accordingly, the rapid torque fluctuation is
suppressed, and a starting impact is reduced. Further, since the
communication between the suction chamber 142 within the compressor
10 and the introduction port 441 is shut off, the amount of the
refrigerant compressed in the front compression chamber 271 and the
rear compression chamber 281 at a time when the valve body 42
exists at the shutoff position is small. Therefore, the effect of
suppressing the torque fluctuation, that is, the effect of reducing
the starting impact is improved.
[0104] (2) If the working pressure within the working pressure
chamber 412 is released, the valve body 42 is returned to the
shutoff position by the spring force of the first return spring 47.
The use of the first return spring 47 simplifies the structure for
returning the valve body 42 to the shutoff position.
[0105] (3) In the case that the valve body 42 exists at the shutoff
position, the introduction port 441, which is an inlet of the
cylinder interior 442 of the valve body 42, enters the working
pressure recess 411 so as to be shielded, and in the case that the
valve body 42 exists at the communication position, the
introduction port 441 is out of the working pressure recess 411 so
as to be exposed to the interior of the suction chamber 142. The
structure in which the introduction port 441 comes in and out with
respect to the interior of the working pressure recess 411 enlarges
the introduction port 441, and is preferable for securing a
sufficient passage cross-sectional area of the introduction
passage.
[0106] FIG. 7 explains a second embodiment in accordance with the
present invention. The structure of the apparatus is the same as
the case of the first embodiment.
[0107] In the second embodiment, the structure of the apparatus is
the same as the case of the first embodiment, however, the second
embodiment is different from the first embodiment in a point that
the amount of the current application is gradually increased at a
time of starting the current application to the electromagnetic
clutch 25, as shown by a current application starting section K21
in a clutch waveform K2. The current application to the
electromagnetic three-way valve 48 is stopped after the feed
current value becomes maximum. The fluctuation of the fluctuation
portion T21 in the torque waveform T2 expressing the torque
fluctuation is suppressed more than the case of the first
embodiment, on the basis of the current application start mentioned
above to the electromagnetic clutch 25.
[0108] For example, in the conventional fixed displacement type
piston compressor having no switch portion, the torque at a time of
starting is great, that is, the load applied to the electromagnetic
clutch 25 is great. Accordingly, if the amount of the current
application is gradually increased in the same manner as the
present invention, in the conventional compressor, a slip is
generated in the electromagnetic clutch 25. Therefore, in the
conventional compressor, it is hard to secure a reliability of the
electromagnetic clutch 25.
[0109] In the present embodiment, since the torque at a time of
starting is small, that is, the load applied to the electromagnetic
clutch 25 is small, it is possible to carry out an operation
control such as to gradually increase the amount of the current
application to the electromagnetic clutch 25.
[0110] FIGS. 8 and 9 explain a third embodiment. The same reference
numerals are attached to the same components as those of the first
embodiment.
[0111] As shown in FIG. 8, a check valve 68 is arranged in a
portion 34A of an external refrigerant circuit 34 in an upstream
side of the heat exchanger 37, and the portion 34A of the external
refrigerant circuit 34 in the upstream side of the check valve 68
is connected to the working pressure chamber 412 by the
communication port 401 and the inflow passage L. The check valve 68
is provided in the portion 34A of the external refrigerant circuit
34 in a downstream side of a connection portion between the portion
34A of the external refrigerant circuit 34 and the inflow passage
L. The interior of the portion 34A of the external refrigerant
circuit 34 is a discharge pressure zone. An electromagnetic on-off
valve 67 is arranged in the inflow passage L. The electromagnetic
on-off valve 67 and the check valve 68 construct a working pressure
applying portion. The electromagnetic on-off valve 67, which serves
as a switch valve, is under the magnetizing and demagnetizing
control of the control computer C. In FIG. 8, the electromagnetic
on-off valve 67 is in a magnetized state, and the electromagnetic
on-off valve 67 is in an open state, in which the inflow passage L
is opened. In the case that the electromagnetic on-off valve 67 is
in the magnetized state, the refrigerant (the discharge
refrigerant) in the portion 34A of the external refrigerant circuit
34 in the upstream side of the check valve 68 can flow in the
working pressure chamber 412. In FIG. 9A, the electromagnetic
on-off valve 67 is in the demagnetized state, and the
electromagnetic on-off valve 67 is in a closed state, in which the
inflow passage L is shut off. The electromagnetic on-off valve 67
is a normally closed type electromagnetic on-off valve which is
closed in a non-excited state (a demagnetized state). However, even
in the case that the electromagnetic on-off valve 67 is in the
closed state, some amount of gas can leak.
[0112] A waveform W1 in a timing chart in FIG. 9B shows a feed
timing of the electric current with respect to the electromagnetic
on-off valve 67. The current application to the electromagnetic
on-off valve 67 is started after [for example, after one second,
(t6-t1) after in the illustrated example] the current application
to the electromagnetic clutch 25 is started, and the current
application stop after the current application to the
electromagnetic on-off valve 67 is the same as the ending time with
respect to the electromagnetic clutch 25 [the current application
is stopped at a clutch ending time t2 in the example in FIG.
9B].
[0113] In the case that the current application to the
electromagnetic clutch 25 is stopped, the current application to
the electromagnetic on-off valve 67 is simultaneously stopped, and
the electromagnetic on-off valve 67 gives way to the closed state
from the open state. If the current application to the
electromagnetic clutch 25 is stopped, that is, if the operation of
the compressor 10 is stopped, the refrigerant is not discharged, so
that the check valve 68 is closed. Accordingly, the balancing of
the pressure within the compressor 10 is rapidly advanced.
[0114] In the case that the operation of the compressor 10 is
stopped, the electromagnetic on-off valve 67 is in the closed
state. However, since some amount of gas can leak in the
electromagnetic on-off valve 67, the refrigerant having the
discharge pressure remaining within the working pressure chamber
412 and within a portion of the inflow passage L between the
communication port 401 and the electromagnetic on-off valve 67
leaks out to the portion 34A in the external refrigerant circuit 34
in the upstream side of the check valve 68 via the electromagnetic
on-off valve 67. Accordingly, the balancing of the pressure within
the working pressure chamber 412 is advanced. Therefore, the valve
body 42 is arranged at the shutoff position shown in FIG. 9A on the
basis of the spring force of the first return spring 47 by a time
point [a time t1 in the example in FIG. 9B] when the current
application to the electromagnetic clutch 25 is next started.
[0115] The electromagnetic on-off valve 67 is in the demagnetized
state (the closed state) before the current application to the
electromagnetic clutch 25 is started, and the current application
to the electromagnetic on-off valve 67 is started after the current
application to the electromagnetic clutch 25. Accordingly, the
valve body 42 is in a state of being at the shutoff position for
some amount of time after the current application to the
electromagnetic clutch 25 is started, and the refrigerant within
the suction chamber 142 does not flow in the in-shaft passage 31.
Therefore, the starting impact at a time of starting the compressor
10 is reduced.
[0116] If the current application to the electromagnetic on-off
valve 67 is started after the current application to the
electromagnetic clutch 25 is started, the electromagnetic on-off
valve 67 gives way to the open state from the closed state, and the
portion 34A of the external refrigerant circuit 34 in the upstream
side of the check valve 68 communicates with the working pressure
chamber 412. After starting the current application to the
electromagnetic clutch 25 (that is, after the operation of the
compressor 10 is started), the check valve 68 is maintained in the
open state on the basis of the discharge of the refrigerant, and
the discharged refrigerant is circulated to the suction chamber 142
via the external refrigerant circuit 34. In the case in which the
current application to the electromagnetic clutch 25 is maintained
(that is, a state in which the compressor 10 is operated), the
electromagnetic on-off valve 67 is maintained in the open state,
and the refrigerant pressure (the discharge pressure) in the
portion 34A of the external refrigerant circuit 34 in the upstream
side of the check valve 68 is applied to the working pressure
chamber 412 via the inflow passage L and the electromagnetic on-off
valve 67. Accordingly, the valve body 42 is arranged at a
communication position shown in FIG. 8.
[0117] The check valve 68, the electromagnetic on-off valve 67, the
working pressure chamber 412, and the valve body 42 construct a
switch portion. The switch portion is capable of switching the
suction chamber 142, which is a portion of the suction pressure
zone within the compressor 10, to a communication state, in which
the suction chamber 142 communicates with the front outlet 312 and
the rear outlet 313 in the introduction passage, and a shutoff
state, in which the suction chamber 142 is shut off from the front
outlet 312 and the rear outlet 313. In FIG. 8, the electromagnetic
on-off valve 67 is in a first state (a magnetized state), in which
the on-off valve 67 can feed the refrigerant in the portion 34A of
the external refrigerant circuit 34, which is a discharge pressure
zone, to the working pressure chamber 412. In FIG. 9A, the
electromagnetic on-off valve 67 is in a second state (a
demagnetized state), in which the on-off valve cannot feed the
refrigerant in the portion of the external refrigerant circuit 34
to the working pressure chamber 412.
[0118] The third embodiment has the same advantages as those of the
first embodiment.
[0119] FIGS. 10 to 11B explain a fourth embodiment. The same
reference numerals are attached to the same components as those of
the third embodiment.
[0120] In the fourth embodiment, a normally open type
electromagnetic on-off valve 67A is used in place of the normally
closed type electromagnetic on-off valve 67 in the third
embodiment. The normally open type electromagnetic on-off valve 67A
is opened in the non-excited state, and is closed in the excited
state. In FIG. 10, the electromagnetic on-off valve 67A, which
serves as a switch valve, opens the inflow passage L in the
non-excited state. In FIG. 11A, the electromagnetic on-off valve
67A closes the inflow passage L in the excited state. The
electromagnetic on-off valve 67A and the check valve 68 construct
the working pressure applying portion.
[0121] A waveform W2 in a timing chart in FIG. 11B shows a current
feed timing with respect to the electromagnetic on-off valve 67A.
At a time when the current application to the electromagnetic
clutch 25 is started, the current application to the
electromagnetic on-off valve 67A has already been started [at a
time t3 in the illustrated example] before the current application
to the electromagnetic clutch 25 is started [at a time t1 in the
illustrated example], and the current application to the
electromagnetic on-off valve 67A is stopped [at a time t4 in the
illustrated example] after the current application to the
electromagnetic clutch 25 is started.
[0122] If the operation of the compressor 10 is stopped, the
refrigerant is not discharged, so that the check valve 68 is
closed. Accordingly, the balancing of the pressure within the
compressor 10 is rapidly advanced. In the case that the operation
of the compressor 10 is stopped, the electromagnetic on-off valve
67A is in the open state. Accordingly, the refrigerant having the
discharge pressure remaining within the working pressure chamber
412, and within a portion of the inflow passage L between the
communication port 401 and the electromagnetic on-off valve 67A
leaks out to the portion 34A of the external refrigerant circuit 34
in the upstream side of the check valve 68 via the electromagnetic
on-off valve 67A. Therefore, the balancing of the pressure within
the working pressure chamber 412 is rapidly advanced. Accordingly,
the valve body 42 is arranged at a shutoff position shown by FIG.
11A on the basis of the spring force of the first return spring 47
by a time point when the current application to the electromagnetic
clutch 25 is next started. The valve body 42 is located at the
shutoff position over a time period from before the current
application to the electromagnetic clutch 25 is started [(t1-t3)
before in the illustrated example] to after the current application
is started [(t4-t1) after in the illustrated example], and the
refrigerant within the suction chamber 142 does not flow in the
in-shaft passage 31. Accordingly, the starting impact at a time of
starting the compressor 10 is reduced.
[0123] The check valve 68, the electromagnetic on-off valve 67A,
the working pressure chamber 412 and the valve body 42 construct a
switch portion. The switch portion is capable of switching the
suction chamber 142, which is a portion of the suction pressure
zone within the compressor 10, to a state in which the suction
chamber 142 communicates with the outlet of the introduction
passage, and a state in which the suction chamber 142 is shut off.
In FIG. 10, the electromagnetic on-off valve 67A is in a first
state (a demagnetized state), in which the refrigerant in the
portion 34A of the external refrigerant circuit 34, which is a
discharge pressure zone, can be fed to the working pressure chamber
412. In FIG. 11A, the electromagnetic on-off valve 67 is in a
second state (a magnetized state), in which the refrigerant in the
portion 34A of the external refrigerant circuit 34 cannot be fed to
the working pressure chamber 412.
[0124] The fourth embodiment has the same advantages as those of
the first embodiment.
[0125] FIGS. 12A and 12B explain a fifth embodiment in accordance
with the present invention. The same reference numerals are used in
the same components as those of the first embodiment.
[0126] A guide cylinder 45A fitted to the cylinder portion 44 of
the valve body 42 is formed as a closed-end cylindrical shape, and
is formed independently from the rear cylinder block 12, the rotary
shaft 21 and the like. A bottom wall of the guide cylinder 45A
comes into contact with an end surface 122 of the rear cylinder
block 12. The guide cylinder 45A is fitted to the cylinder portion
44 of the valve body 42 in such a manner as to be allowed to move
in a radial direction of the rotary shaft 21 with respect to the
rotary shaft 21. A communication port 452 is formed in a bottom
wall of the guide cylinder 45A in such a manner as to connect the
cylinder interior 451 of the guide cylinder 45A with the in-shaft
passage 31. The first return spring 47 is arranged between the
bottom wall of the guide cylinder 45A and the piston portion 43.
The valve body 42 is arranged at a communication position in FIG.
12A, and the valve body 42 is arranged at a shutoff position in
FIG. 12B. The magnetizing and demagnetizing timings of the
electromagnetic three-way valve 48 are identical with the case of
the first embodiment.
[0127] On the assumption that the refrigerant leaks through
clearance between the valve body 42 and the cylinder 41 or
clearance between the valve body 42 and the guide cylinder at a
time when the valve body 42 is in a state of being at the shutoff
position, the effect of reducing the starting impact is
lowered.
[0128] However, the guide cylinder 45A of the present embodiment is
fitted to the cylinder portion 44 of the valve body 42 in such a
manner that the guide cylinder 45A is allowed to move in the radial
direction of the rotary shaft 21 with respect to the rotary shaft
21. Accordingly, an axis 413 of the working pressure recess 411 is
allowed to come into line with an axis 453 of the guide cylinder
45A. Therefore, it is possible to reduce a clearance between the
cylinder portion 44 of the valve body 42 and the cylinder 41 and a
clearance between the cylinder portion 44 of the valve body 42 and
the guide cylinder 45A, and it is possible to prevent the
refrigerant from leaking along a peripheral surface of the cylinder
portion 44 of the valve body 42.
[0129] FIGS. 13 and 14 explain a sixth embodiment. The same
reference numerals are used in the same components as those of the
first embodiment.
[0130] A piston 69 is slidably fitted to the cylinder 41, and a
transmission rod 70 is coupled to the piston 69. The piston 69
defines the working pressure chamber 412 within the working
pressure recess 411. The transmission rod 70 enters an in-shaft
passage 31A. The in-shaft passage 31A is provided with a
small-diameter passage 314, and a large-diameter passage 315 having
a larger diameter than the small-diameter passage 314. A
cylindrical small circumferential surface body 71 is fastened to a
portion of the transmission rod 70 positioned within the
small-diameter passage 314. A cylindrical large circumferential
surface body 72 is fastened to a portion of the transmission rod 70
positioned within the large-diameter passage 315. The cylindrical
small circumferential surface body 71 is fitted to the
small-diameter passage 314 in such a manner as to be slidable in a
direction of a rotation axis 210 of the rotary shaft 21, and be
capable of opening and closing the front outlet 312, and the
cylindrical large circumferential surface body 72 is fitted to the
large-diameter passage 315 in such a manner as to be slidable in
the direction of the rotation axis 210 of the rotary shaft 21, and
be capable of opening and closing the rear outlet 313. The interior
of the cylindrical large circumferential surface body 72
communicates a portion of the in-shaft passage 31A between the
small circumferential surface body 71 and the large circumferential
surface body 72 with a portion of the in-shaft passage 31A between
the inlet 311 of the in-shaft passage 31A and the large
circumferential surface body 72.
[0131] A first return spring 73 is arranged between a step 316
between the small-diameter passage 314 and the large-diameter
passage 315, and the large circumferential surface body 72. The
first return spring 73 urges a whole of the small circumferential
surface body 71, the large circumferential surface body 72, the
transmission rod 70 and the piston 69 toward the working pressure
chamber 412 in such a manner as to press the piston 69 to the
working pressure recess 411. The small circumferential surface body
71, the large circumferential surface body 72, the transmission rod
70 and the piston 69 construct a valve body defining the working
pressure chamber 412 within the working pressure recess 411.
[0132] FIG. 14 shows a state in which the small circumferential
surface body 71 closes the front outlet 312, and the large
circumferential surface body 72 closes the rear outlet 313. The
front outlet 312 and the rear outlet 313 are shut off from the
in-shaft passage 31A. FIG. 13 shows a state in which the small
circumferential surface body 71 opens the front outlet 312, and the
large circumferential surface body 72 opens the rear outlet 313.
The front outlet 312 and the rear outlet 313 communicate with the
in-shaft passage 31A. If the current application to the
electromagnetic three-way valve 48 is carried out, the small
circumferential surface body 71 and the large circumferential
surface body 72 are arranged at a shutoff position shown in FIG. 14
from a communication position shown in FIG. 13, on the basis of a
spring force of the first return spring 73. The magnetizing and
demagnetizing timings of the electromagnetic three-way valve 48 are
identical with the case of the first embodiment.
[0133] The sixth embodiment has the same advantages as those of the
first embodiment. Further, in the sixth embodiment, since the
refrigerant which can flow in the front compression chamber 271 and
the rear compression chamber 281 at a time when the small
circumferential surface body 71 and the large circumferential
surface body 72 are at the shutoff position is constituted only by
the refrigerant within the front outlet 312, within the rear outlet
313, within the front communication passage 32, and within the rear
communication passage 33, the effect of reducing the starting
impact is more noticeable than the case of the first
embodiment.
[0134] In the case that the piston 69 is structured such as to be
relatively rotatable with respect to the transmission rod 70, the
piston 69 prevents the relative rotation between the first return
spring 73 and the rotary shaft 21. Accordingly, it is possible to
avoid an abrasion and damage of the first return spring 73 or the
rotary shaft 21 caused by the relative rotation between the first
return spring 73 and the rotary shaft 21. Alternatively, the large
circumferential surface body 72 may be structured such as to be
relatively rotatable with respect to the first return spring
73.
[0135] FIGS. 15A and 15B explain a seventh embodiment. The same
reference numerals are used in the same components as those of the
sixth embodiment.
[0136] A disc-shaped circular plate 74 is fastened to a distal end
of the transmission rod 70. As shown in FIG. 15A, in the case that
the large circumferential surface body 72 is located at a position
at which the large circumferential surface body 72 closes the rear
outlet 313, the circular plate 74 is located in an upstream side of
the front outlet 312 within the in-shaft passage 31A, and the
refrigerant in the in-shaft passage 31A cannot flow in the front
compression chamber 271 via the front outlet 312. As shown in FIG.
15B, in the case that the large circumferential surface body 72 is
located at a position at which the large circumferential surface
body 72 opens the rear outlet 313, the circular plate 74 is located
in a downstream side of the front outlet 312 within the in-shaft
passage 31A, and the refrigerant in the in-shaft passage 31A can
flow in the front compression chamber 271 via the front outlet 312.
If the electromagnetic three-way valve 48 [refer to FIG. 14] is
excited, the circular plate 74 is arranged at a shutoff position
shown in FIG. 15A from a communication position shown in FIG. 15B,
on the basis of the spring force of the first return spring 73. The
circular plate 74, the large circumferential surface body 72, the
transmission rod 70 and the piston 69 construct the valve body
defining the working pressure chamber 412 within the working
pressure recess 411.
[0137] The seventh embodiment has the same advantages as those of
the sixth embodiment.
[0138] FIGS. 16A and 16B explain an eighth embodiment. The same
reference numerals are used in the same components as those of the
sixth embodiment.
[0139] A cylinder 75 is coupled to the piston 69 so as to be
relatively rotatable with respect to the piston 69. The cylinder 75
is slidably fitted to the in-shaft passage 31A. An end wall 752 is
formed in a distal end of the cylinder 75. An angular pin 76 is
fastened to an inner end which is a dead end of the in-shaft
passage 31A, and the angular pin 76 is inserted to the end wall 752
of the cylinder 75 so as to be relatively slidable. The cylinder 75
and the angular pin 76 are integrally rotated with the rotary shaft
21, and can slide within the in-shaft passage 31A in a state in
which the angular pin 76 is inserted to the end wall 752.
[0140] The cylinder 75 is provided with a small-diameter
cylindrical portion 77, which is fitted into the small-diameter
passage 314, and a large-diameter cylindrical portion 78, which is
fitted to the large-diameter passage 315. An introduction port 751
is formed in a portion of the large-diameter cylindrical portion 78
positioned within the suction chamber 142 so as to be capable of
connecting the suction chamber 142 with a cylinder interior 750 of
the cylinder 75.
[0141] A communication port 771 is formed in a portion of the
small-diameter cylindrical portion 77 within the small-diameter
passage 314 so as to communicate with the inside of the
small-diameter cylindrical portion 77. A communication port 781 is
formed in the large-diameter cylindrical portion 78 so as to
communicate with the interior of the large-diameter cylindrical
portion 78.
[0142] The first return spring 73 is arranged between a step 753
between the small-diameter cylindrical portion 77 and the
large-diameter cylindrical portion 78, and the step 316 of the
rotary shaft 21. The first return spring 73 urges the cylinder 75
toward the working pressure chamber 412 in such a manner as to
press the piston 69 to the working pressure recess 411. The piston
69 and the cylinder 75 construct a valve body defining the working
pressure chamber 412 within the working pressure recess 411.
[0143] FIG. 16B shows a state in which the small-diameter
cylindrical portion 77, which serves as a valve body, closes the
front outlet 312, and shows a state in which the large-diameter
cylindrical portion 78, which serves as a valve body, closes the
rear outlet 313. Accordingly, the front outlet 312 and the rear
outlet 313 are shut off from the cylinder interior 750 of the
cylinder 75. FIG. 16A shows a state in which the communication port
771 of the small-diameter cylindrical portion 77 communicates with
the front outlet 312, and shows a state in which the communication
port 781 of the large-diameter cylindrical portion 78 communicates
with the rear outlet 313, and the front outlet 312 and the rear
outlet 313 communicate with the cylinder interior 750. The
refrigerant in the suction chamber 142 can flow in the front
compression chamber 271 via the introduction port 751, the cylinder
interior 750, the communication port 771, the front outlet 312, and
the front communication passage 32, and the refrigerant in the
suction chamber 142 can flow in the rear compression chamber 281
via the introduction port 751, the cylinder interior 750, the
communication port 781, the rear outlet 313, and the rear
communication passage 33. If the electromagnetic three-way valve 48
[refer to FIG. 14] is excited, the cylinder 75 is arranged from a
communication position shown in FIG. 16A to a shutoff position
shown in FIG. 16B on the basis of the spring force of the first
return spring 73. The magnetizing and demagnetizing timings of the
electromagnetic three-way valve 48 are the same as those of the
first embodiment.
[0144] The eighth embodiment has the same advantages as those of
the sixth embodiment.
[0145] FIGS. 17 to 18B explain a ninth embodiment. The same
reference numerals are used in the same components as those of the
fifth embodiment.
[0146] As shown in FIG. 17, a check valve built-in type oil
separator 79 is arranged in the portion 34A of the external
refrigerant circuit 34 which is located in an upstream side of the
heat exchanger 37.
[0147] As shown in FIGS. 18A and 18B, a refrigerant swirling
cylinder 81 is fixed in a fitting manner into a housing 80
constructing the oil separator 79. The refrigerant swirling
cylinder 81 defines an oil separation chamber 82 and a valve
accommodation chamber 83 in the housing 80. The oil separation
chamber 82 communicates with the portion 34A of the external
refrigerant circuit 34 which is located in the upstream side of the
oil separator 79, and the refrigerant in the portion 34A of the
external refrigerant circuit 34 flows into the oil separation
chamber 82. The refrigerant flowing into the oil separation chamber
82 from the portion 34A of the external refrigerant circuit 34
swirls around the refrigerant swirling cylinder 81. The refrigerant
swirling around the refrigerant swirling cylinder 81 flows in a
cylinder interior 812 from a cylinder port 811 of the refrigerant
swirling cylinder 81 facing the oil separation chamber 82.
[0148] A valve body 85 is accommodated in the valve accommodation
chamber 83. The valve body 85 is capable of opening and closing the
other cylinder port 813 of the refrigerant swirling cylinder 81.
The valve body 85 is urged toward a position closing the cylinder
port 813 by a compression spring 86. If a pressure of the
refrigerant within the cylinder interior 812 overcomes a spring
force of the compression spring 86, the refrigerant of the cylinder
interior 812 pushes the valve body 85 so as to flow out to the
valve accommodation chamber 83. The refrigerant swirling cylinder
81, the valve body 85 and the compression spring 86 construct a
check valve 87. The refrigerant in the valve accommodation chamber
83 flows in the heat exchanger 37.
[0149] A constriction hole 402 extends through the end wall 40. The
constriction hole 402, which serves as a constriction, connects the
working pressure chamber 412 with a conduit 84. The oil separation
chamber 82 communicates with the working pressure chamber 412 via
the conduit 84 and the constriction hole 402. The pressure (the
discharge pressure) within the oil separation chamber 82 is applied
to the working pressure chamber 412 via the conduit 84 and the
constriction hole 402. The constriction hole 402 and the conduit 84
construct a portion of an inflow passage which is located in a
downstream side of the oil separator 79.
[0150] The oil is charged within the circuit constituted by the
compressor 10 and the external refrigerant circuit 34, and the oil
flows with the refrigerant.
[0151] The refrigerant flowing in the oil separation chamber 82
from the portion 34A of the external refrigerant circuit 34 swirls
around the refrigerant swirling cylinder 81, and a mist-like oil
flowing together with the refrigerant is separated within the oil
separation chamber 82. The refrigerant swirling around the
refrigerant swirling cylinder 81 flows in the cylinder interior
812, and the oil separated from the refrigerant can flow in the
working pressure chamber 412 via the conduit 84 and the
constriction hole 402. The conduit 84 and the constriction hole 402
construct an inflow passage reaching the portion 34A of the
external refrigerant circuit 34, which is a discharge pressure
zone, from the working pressure chamber 412.
[0152] In the case that the operation of the compressor 10 stops
and the pressure within the compressor 10 is balanced, the valve
body 42 is retained at a shutoff position shown in FIG. 18B on the
basis of the spring force of the first return spring 47. In the
case that the operation of the compressor 10 is started, the
refrigerant does not flow in the in-shaft passage 31 from the
suction chamber 142, so that the starting impact is reduced.
[0153] If the pressure within the oil separation chamber 82 is
increased in accordance with the start of the operation of the
compressor 10, the pressure within the working pressure chamber 412
is also increased, and the valve body 42 is arranged at the
communication position shown in FIG. 18A against the spring force
of the first return spring 47. Since the constriction hole 402
narrows a passage cross-sectional area between the conduit 84 and
the working pressure chamber 412, the pressure within the working
pressure chamber 412 is not rapidly increased even if the pressure
within the front discharge chamber 131 and the rear discharge
chamber 141 is increased. Further, since the oil separated by the
oil separator 79 enters the constriction hole 402, the oil entering
the constriction hole 402 generates a passage resistance so as to
contribute to a suppression of a rapid increase of the pressure
within the working pressure chamber 412. Since the rapid increase
of the pressure within the working pressure chamber 412 is
suppressed, the valve body 42 is not moved from the shutoff
position to the communication position in a moment of time.
Accordingly, the reducing effect of the starting impact is
increased.
[0154] Since the ninth embodiment does not use the electromagnetic
three-way valve 48 and the electromagnetic on-off valve 67, the
ninth embodiment is advantageous in cost compared with those of the
first to the fifth embodiments.
[0155] FIGS. 19A and 19B explain a tenth embodiment. The same
reference numerals are used in the same components as those of the
first embodiment.
[0156] A communication chamber 88 and a valve hole 891 are formed
in the rear housing member 14, and a plate-shaped opening and
closing plate 90 is accommodated within the communication chamber
88 in such a manner as to be capable of opening and closing the
valve hole 891. The valve hole 891 extends through a partition wall
89 which separates the communication chamber 88 and the suction
chamber 142. An inlet 311 of the in-shaft passage 31 is positioned
at an end surface of the rotary shaft 21 within the rear cylinder
block 12, and is open to the communication chamber 88 within the
rear housing member 14.
[0157] A piston 91 is fitted into the working pressure recess 411,
and a transmission rod 92 is integrally formed in the piston 91.
The opening and closing plate 90 is fastened to a distal end of the
transmission rod 92. A flat valve seat surface 892 is formed in a
surface of the partition wall 89 facing the communication chamber
88. The opening and closing plate 90 selectively contacts and
separates from the valve seat surface 892. A seal surface 901 of
the opening and closing plate 90 coming into contact with the valve
seat surface 892 is formed as a flat surface. In other words, in
the case that the opening and closing plate 90 closes the valve
hole 891, the seal surface 901 of the opening and closing plate 90
comes into surface contact with the valve seat surface 892. The
piston 91, the transmission rod 92 and the opening and closing
plate 90 define the working pressure chamber 412 within the working
pressure recess 411, and construct a valve body 93 opening and
closing the valve hole 891.
[0158] A first return spring 94 is arranged between the piston 91
and the partition wall 89. The first return spring 94 urges the
piston 91 in a direction in which the first return spring 94
presses the piston 91 to the working pressure recess 411. The valve
body 93 in FIG. 19B is located at a communication position at which
the valve body 93 connects the communication chamber 88 with the
suction chamber 142 by opening the valve hole 891, and the valve
body in FIG. 19A is located at a shutoff position at which the
valve body 93 shuts off the communication chamber 88 from the
suction chamber 142 by closing the valve hole 891. The first return
spring 94 urges the valve body 93 from the communication position
toward the shutoff position.
[0159] A plurality of stoppers 902 are provided in a protruding
manner in a back surface of the opening and closing plate 90 facing
the end surface of the rotary shaft 21. The stopper 902 selectively
contacts and separates from a distal end of a cylindrical portion
123 provided in a protruding manner in an end surface 122 of the
rear cylinder block 12. In a state in which the valve body 93 is
arranged at the communication position shown in FIG. 19B, the
stopper 902 is brought into contact with the distal end of the
cylindrical portion 123, and in a state in which the valve body 93
is arranged at the shutoff position shown in FIG. 19A, the stopper
902 is away from the distal end of the cylindrical portion 123.
[0160] In a state in which the electromagnetic three-way valve 48
is magnetized, the valve body 93 is arranged at the shutoff
position shown in FIG. 19A, and the refrigerant within the suction
chamber 142 cannot flow in the communication chamber 88. In a state
in which the electromagnetic three-way valve 48 is demagnetized,
the valve body 93 is arranged at the communication position shown
in FIG. 19B, and the refrigerant within the suction chamber 142 can
flow in the front compression chamber 271 (refer to FIG. 1) and the
rear compression chamber 281 via the communication chamber 88 and
the in-shaft passage 31.
[0161] The magnetizing and demagnetizing timings of the
electromagnetic three-way valve 48 are the same as the case of the
first embodiment. Accordingly, the tenth embodiment also obtains
the reducing effect of the starting impact. Further, since it is
possible to reduce the volumetric capacity of the communication
chamber 88 accommodating the plate-shaped opening and closing plate
90, the reducing effect of the starting impact is noticeable in the
same manner as the case of the first embodiment.
[0162] FIG. 20 shows a fixed displacement type piston compressor
10A in accordance with an eleventh embodiment. The compressor 10A
has a plurality of one headed pistons 95. The same reference
numerals are used in the same components as those of the first
embodiment.
[0163] A whole housing of the compressor 10A is constituted by the
cylinder block 12, the front housing member 13, and the rear
housing member 14. The swash plate 23 is accommodated in the swash
plate chamber 24 defined between the cylinder block 12 and the
front housing member 13. A one headed piston 95 linked to the swash
plate 23 reciprocates within the cylinder bore 28 in accordance
with the rotation of the swash plate 23. The rotary valve 36 is
provided in the rotary shaft 21 so as to correspond to the cylinder
block 12. The valve body 42 is provided in the rear housing member
14 so as to define the working pressure chamber 412.
[0164] The eleventh embodiment also has the same advantages as
those of the first embodiment.
[0165] FIGS. 21 to 26 show a twelfth embodiment in accordance with
the present invention.
[0166] As shown in FIG. 21, the in-shaft passage 31 is formed
within the rotary shaft 21 so as to be along the rotation axis 210
of the rotary shaft 21. The communication chamber 88 and the valve
hole 891 are formed in the rear housing member 14, and the
plate-shaped opening and closing plate 90 is accommodated within
the communication chamber 88 in such a manner as to be capable of
opening and closing the valve hole 891. The valve hole 891 extends
through the partition wall 89 which separates the communication
chamber 88 and the suction chamber 142. The inlet 311 of the
in-shaft passage 31 is positioned in the end surface of the rotary
shaft 21 within the rear cylinder block 12, and is open to the
communication chamber 88 within the rear housing member 14.
[0167] As shown in FIGS. 23 and 24, an electromagnetic solenoid
248, which serves as an electromagnetic drive portion, is attached
to the end wall 40 of the rear housing member 14. The rear housing
member 14 is made of aluminum and forms the suction chamber 142. An
installation recess 404 is formed in a recessed manner in an outer
surface of the end wall 40. The electromagnetic solenoid 248
includes a fixed iron core 250, a movable iron core 251, a second
return spring 252, and a coil 253.
[0168] The fixed iron core 250 is fitted to the installation recess
404, and a coil 253 is embedded in the fixed iron core 250. The
installation recess 404 is connected to the suction chamber 142. A
pressure recess 260, which serves as a pressure chamber forming
recess, is formed in a recessed manner in the fixed iron core 250.
The pressure recess 260 is open toward the suction chamber 142. The
movable iron core 251 is slidably fitted to the pressure recess
260. The movable iron core 251 defines a pressure chamber 262
within the pressure recess 260. A groove 254 is formed in a
peripheral surface of the movable iron core 251. The groove 254
connects the pressure recess 260 with the suction chamber 142.
Accordingly, the pressure within the pressure chamber 262
corresponds to the pressure within the suction chamber 142. The
pressure of the suction chamber 142, that is, the suction pressure
acts against a pressure in the pressure chamber 262 via the movable
iron core 251. A lid 258 fastened to the outer surface of the end
wall 40 retains the fixed iron core 250 and the coil 253 within the
installation recess 404.
[0169] The movable iron core 251 has an attaching hole 255, which
serves as a through hole. The attaching hole 255 extends through
the movable iron core 251 in such a manner as to be connected to
the suction chamber 142 from the pressure recess 260. The
transmission rod 92 is press fitted to the attaching hole 255 from
an opening of the attaching hole 255 facing the suction chamber
142, and is fixed thereto. The opening and closing plate 90 is
fastened to a distal end of the transmission rod 92.
[0170] The movable iron core 251, the transmission rod 92 and the
opening and closing plate 90 construct the valve body 242 opening
and closing the valve hole 891. The valve body 242 defines the
pressure chamber 262 within the pressure recess 260.
[0171] The second return spring 252 is arranged between the
transmission rod 92 and a bottom 261 of the pressure recess 260.
The second return spring 252 urges the transmission rod 92 in a
direction in which the second return spring 252 moves the
transmission rod 92 away from the bottom 261. In other words, the
movable iron core 251 is urged in a direction in which the movable
iron core 251 pops out of the pressure recess 260 toward the
suction chamber 142, on the basis of the spring force of the second
return spring 252. The electromagnetic solenoid 248, the valve body
242 and the second return spring 252 construct a switch portion.
The switch portion is capable of switching the suction chamber 142,
which serves as a portion of the suction pressure zone within the
compressor 10, to a communication state, in which the suction
chamber 142 communicates with the front outlet 312 and the rear
outlet 313 of the in-shaft passage 31, and a shutoff state, in
which the suction chamber 142 is shut off from the front outlet 312
and the rear outlet 313.
[0172] In FIG. 23, the valve body 242 is located in the
communication position, at which the valve body 242 connects the
communication chamber 88 with the suction chamber 142, by opening
the valve hole 891. In FIG. 24, the valve body 242 is located at
the shutoff position at which the valve body 242 shuts off the
communication chamber 88 from the suction chamber 142 by closing
the valve hole 891. The second return spring 252 urges the valve
body 242 from the shutoff position toward the communication
position. In other words, the switch portion is capable of
switching the suction chamber 142 to a communication state [a state
shown in FIG. 23], in which the suction chamber 142 communicates
with the front outlet 312 and the rear outlet 313 of the in-shaft
passage 31, and a shutoff state [a state shown in FIG. 24], in
which the suction chamber 142 is shut off from the front outlet 312
and the rear outlet 313 of the in-shaft passage 31.
[0173] If the electric current is fed to the coil 253, the fixed
iron core 250 attracts the movable iron core 251 against a spring
force of the second return spring 252. In other words, an
electromagnetic force generated by exciting the coil 253 drives the
valve body 242 from the communication position toward the shutoff
position. The electromagnetic solenoid 248 can be switched to a
first state, in which the electromagnetic solenoid 248 arranges the
valve body 242 at the communication position by being demagnetized,
and a second state, in which the electromagnetic solenoid 248
arranges the valve body 242 at the shutoff position by being
magnetized.
[0174] The magnetizing and demagnetizing of the electromagnetic
solenoid 248 and the electromagnetic clutch 25 are controlled by
the control computer C.
[0175] A valve waveform W in a timing chart in FIG. 26 shows a
current feeding timing with respect to the electromagnetic solenoid
248. A first exciting period section V1 in the valve waveform W is
set in correspondence to a clutch starting time t1. A starting time
t3 of the first exciting period section V1 is before the clutch
starting time t1, and an ending time t4 of the first exciting
period section V1 is after the clutch starting time t1. In other
words, the control computer C first carries out the current feed to
the electromagnetic solenoid 248 and thereafter carries out the
current feed to the electromagnetic clutch 25, at a time of
starting the current feed to the electromagnetic clutch 25.
[0176] FIG. 25 is a flowchart showing an operation control program
for controlling the operation of the compressor 10, and the control
computer C controls the operation of the compressor 10 on the basis
of the operation control program shown by the flowchart. A
description will be given below of the operation control of the
compressor 10 in accordance with the operation control program
shown by the flowchart. FIG. 25 has steps S1 to S7 and S18. Steps
S1 to S7 are the same as the case of FIG. 5 except the matter that
the electromagnetic three-way valve 48 is replaced by the
electromagnetic solenoid 248.
[0177] If the compressor 10 is in the operation stop state, and the
electromagnetic solenoid 248 is in the demagnetized state, the
valve body 242 is arranged at the communication position shown in
FIG. 23 on the basis of the spring force of the second return
spring 252.
[0178] As shown in FIG. 23, in the case of YES in step S1, that is,
in the case of the compressor operation starting mode, the control
computer C starts the current application to the electromagnetic
solenoid 248 in step S2. If the electric current is fed to the
electromagnetic solenoid 248, the valve body 242 is arranged at the
shutoff position shown in FIG. 24 against the spring force of the
second return spring 252, and the valve hole 891 is closed.
Accordingly, the suction chamber 142 is shut off from the
communication chamber 88.
[0179] In the case of YES in step S3, that is, in the case that a
period ta has elapsed after starting the current application to the
electromagnetic solenoid 248, the control computer C starts the
current application to the electromagnetic clutch 25 in step S4.
Accordingly, the electromagnetic clutch 25 gives way to the coupled
state from the shutoff state, and the rotary shaft 21 and the swash
plate 23 start rotating.
[0180] In the case of YES in step S5, that is, in the case that a
period tb has elapsed after starting the current application to the
electromagnetic clutch 25, the control computer C stops the current
application to the electromagnetic solenoid 248 in step S6. If the
current feed to the electromagnetic solenoid 248 is stopped, the
valve body 242 is arranged at the communication position shown in
FIG. 23 from the shutoff position shown in FIG. 24, on the basis of
the spring force of the second return spring 252. Accordingly, the
valve hole 891 is opened, and the communication chamber 88
communicates with the suction chamber 142. Therefore, the
refrigerant within the suction chamber 142 flows in the in-shaft
passage 31 via the valve hole 891 and the communication chamber
88.
[0181] After stopping the current application to the
electromagnetic solenoid 248, the control computer C determines in
step S7 whether the compressor operation stopping mode is
established, on the basis of the comparison between the detected
temperature and the target temperature. In the case of YES in step
S7, that is, in the case of the compressor operation stopping mode,
the control computer C stops the current application to the
electromagnetic clutch 25 in step S18. After the process of step
S18, the control computer C gives way to step S1.
[0182] The torque waveform T1 in FIG. 26 is one example of the
torque fluctuation. In the case that the current application to the
electromagnetic clutch 25 is started, the torque is fluctuated.
However, at a time of starting the current application to the
electromagnetic clutch 25, it is possible to suppress a rapid
torque fluctuation [a fluctuation portion T11 in the torque
waveform T1] in the case that the current application to the
electromagnetic clutch 25 is started, by exciting the
electromagnetic solenoid 248 before starting the current
application to the electromagnetic clutch 25 and stopping the
current application to the electromagnetic solenoid 248 after
starting the current application to the electromagnetic clutch
25.
[0183] The twelfth embodiment has the following advantages.
[0184] (2-1) In the state in which the electromagnetic solenoid 248
is magnetized, the valve body 242 is arranged at the shutoff
position shown in FIG. 24. If the valve body 242 is arranged at the
shutoff position, the suction chamber 142, which is the suction
pressure zone within the compressor 10, is shut off from the
communication chamber 88. Accordingly, at a time when the operation
of the compressor 10 is started, that is, at a time when the
rotation of the rotary shaft 21 is started, the rotation of the
rotary shaft 21 is started after the valve body 242 is previously
arranged at the shutoff position. Therefore, the refrigerant does
not flow in the communication chamber 88 and the in-shaft passage
31 from the suction chamber 142. Accordingly, the rapid torque
fluctuation is suppressed and the starting impact is reduced.
[0185] (2-2) The opening and closing plate 90 for shutting off the
suction chamber 142 within the compressor 10 from the communication
chamber 88 is shaped like a plate. Accordingly, it is possible to
reduce the volumetric capacity of the communication chamber 88
accommodating the opening and closing plate 90. Therefore, the
amount of the refrigerant compressed by the front compression
chamber 271 and the rear compression chamber 281 is small at a time
when the valve body 242 exists at the shutoff position. As a
result, the effect of suppressing the torque fluctuation, that is,
the effect of reducing the starting impact is noticeable.
[0186] (2-3) If the electromagnetic solenoid 248 is demagnetized,
the valve body 242 is returned to the communication position on the
basis of the spring force of the second return spring 252. The use
of the second return spring 252 simplifies the structure for
returning the valve body 242 to the communication position.
[0187] (2-4) If it is impossible to magnetize the electromagnetic
solenoid 248, the valve body 242 is retained at the communication
position on the basis of the spring force of the second return
spring 252 within the pressure chamber 262. Accordingly, if the
compressor 10 starts being operated, the refrigerant within the
suction chamber 142 flows in the front compression chamber 271 and
the rear compression chamber 281 via the communication chamber 88
and the in-shaft passage 31. In other words, even in the case that
it becomes impossible to magnetize the electromagnetic solenoid
248, the cooling operation is carried out normally.
[0188] (2-5) If the refrigerant leaks from the suction chamber 142
to the communication chamber 88 via the valve hole 891 at a time
when the valve body 242 closes the valve hole 891, the reducing
effect of the starting impact is lowered. However, in accordance
with the present embodiment, the communication chamber 88 is
securely shut off from the suction chamber 142, in the state in
which the flat seal surface 901 of the opening and closing plate 90
comes into surface contact with the flat valve seat surface 892.
Accordingly, it is possible to prevent the refrigerant from leaking
from the suction chamber 142 to the communication chamber 88 via
the valve hole 891, at a time when the valve body 242 closes the
valve hole 891.
[0189] FIG. 27 explains a thirteenth embodiment. The apparatus
structure is the same as the case of the twelfth embodiment.
[0190] In the thirteenth embodiment, the apparatus structure is the
same as the case of the twelfth embodiment, however, as shown by a
current application starting section K21 in a clutch waveform K2,
the thirteenth embodiment is different from the case of the twelfth
embodiment in a point that the amount of current application at a
time of starting the current application to the electromagnetic
clutch 25 is gradually increased. After the feed current value to
the electromagnetic clutch 25 becomes maximum, the current
application to the electromagnetic solenoid 248 is stopped. The
fluctuation of the fluctuation portion T21 in the torque waveform
T2 expressing the torque fluctuation is suppressed in comparison
with the case of the twelfth embodiment, on the basis of the start
of the current application to the electromagnetic clutch 25.
[0191] For example, in a conventional fixed displacement type
piston compressor having no switch portion, the torque at a time of
starting is great, that is, the load of the electromagnetic clutch
25 is great. Accordingly, if the amount of current application is
gradually increased in the same manner as the present embodiment,
slip is generated in the electromagnetic clutch 25. Accordingly, it
is hard to ensure the reliability of the electromagnetic clutch
25.
[0192] In the present embodiment, the torque at a time of starting
is small, that is, the load applied to the electromagnetic clutch
25 is small. Accordingly, it is possible to carry out such an
operation control as to gradually increase the amount of current
application to the electromagnetic clutch 25.
[0193] FIGS. 28A and 28B explain a fourteenth embodiment. The same
reference numerals are attached to the same component as the
twelfth embodiment.
[0194] A valve body 242A is provided with the opening and closing
plate 90, a movable iron core 251A, and a transmission rod 92. The
movable iron core 251A is slidably fitted to a pressure recess 260.
The transmission rod 92 is integrally formed in the movable iron
core 251A. The movable iron core 251A defines a pressure chamber
262 within the pressure recess 260. The first return spring 94 is
arranged between the movable iron core 251A and the partition wall
89. The first return spring 94 urges the valve body 242A in a
direction of pressing the movable iron core 251A into the pressure
recess 260. If the electromagnetic solenoid 248 is magnetized, an
electromagnetic driving force of the electromagnetic solenoid 248
drives the valve body 242A in a direction of pressing the movable
iron core 251A into the pressure recess 260. The first return
spring 94 serves as a retaining spring retaining the valve body
242A at the shutoff position.
[0195] In FIG. 28A, the valve body 242A exists at the shutoff
position at which the valve body 242A closes the valve hole 891,
and in FIG. 28B, the valve body 242A exists at the communication
position at which the valve body 242A opens the valve hole 891. In
the case that the electromagnetic solenoid 248 is in the magnetized
state, the valve body 242A exists at the shutoff position shown in
FIG. 28A on the basis of the electromagnetic force of the
electromagnetic solenoid 248. A timing at which the electromagnetic
solenoid 248 is magnetized is the same as the case of the twelfth
embodiment. In the case that the operation of the compressor 10 is
in the stop state, the valve body 242A is retained at the shutoff
position shown in FIG. 28A on the basis of the spring force of the
first return spring 94.
[0196] If the electromagnetic solenoid 248 is magnetized before the
compressor 10 starts being operated, and the operation of the
compressor 10 is started thereafter, the starting impact is reduced
in the same manner as the case of the twelfth embodiment because
the valve body 242A exists at the shutoff position.
[0197] If the electromagnetic solenoid 248 is demagnetized after
starting the operation of the compressor 10, the valve body 242A is
released from the electromagnetic force of the electromagnetic
solenoid 248. Since the refrigerant within the in-shaft passage 31
and the refrigerant within the communication chamber 88 are drawn
into the front compression chamber 271 (refer to FIG. 21) and the
rear compression chamber 281, a difference is generated between the
pressure within the suction chamber 142 and the pressure within the
communication chamber 88. Accordingly, the opening and closing
plate 90 separates from the valve seat surface 892 against the
spring force of the first return spring 94. If the opening and
closing plate 90 separates from the valve seat surface 892, the
refrigerant within the suction chamber 142 is drawn to the
communication chamber 88 via the valve hole 891. Accordingly, the
pressure within the suction chamber 142 becomes lower than the
pressure within the pressure chamber 262. In other words, a
difference is generated between the pressure within the suction
chamber 142 and the pressure within the pressure chamber 262.
[0198] The spring force of the first return spring 94 is set to
such a magnitude that the first return spring 94 is compressed by
the differential pressure generated between the pressure within the
suction chamber 142 and the pressure within the pressure chamber
262 at a time of operating the compressor 10. In other words, the
spring force of the first return spring 94 is set such as to yield
to the differential pressure mentioned above. Accordingly, the
differential pressure generated between the pressure within the
suction chamber 142 and the pressure within the pressure chamber
262 at a time of operating the compressor 10 overcomes the spring
force of the first return spring 94 and retains the valve body 242A
at the communication position shown in FIG. 28B.
[0199] The fourteenth embodiment has the same advantages as the
items (2-1) and (2-4) in the twelfth embodiment. If the
electromagnetic solenoid 248 is magnetized, it is possible to
securely retain the valve body 242A at the shutoff position. If the
electromagnetic solenoid 248 is in the demagnetized state by
appropriately setting the spring force of the first return spring
94, the valve body 242A is arranged at the communication position
in the case that the compressor 10 is operated, and the cooling
operation is securely carried out.
[0200] FIGS. 29A and 29B explain a fifteenth embodiment. The same
reference numerals are used in the same components as those of the
twelfth embodiment.
[0201] A spool-shaped valve body 342 is slidably fitted into a
pressure recess 611 which is the cylinder interior of the cylinder
41, in the end wall 40 of the rear housing member 14. The valve
body 342 is provided with the disc-shaped piston portion 43, the
cylinder portion 44 and a movable iron core portion 345. A cylinder
interior 442 is an internal passage of the valve body 342. The
piston portion 43 defines a pressure chamber 612 within the
pressure recess 611.
[0202] A groove 443 is formed in an outer peripheral surface of the
cylinder portion 44 in such a manner that the groove 443 connects
the suction chamber 142 with the pressure chamber 612. A pressure
in the pressure chamber 612 corresponds to a pressure in the
suction chamber 142, and the pressure (the suction pressure) in the
suction chamber 142 acts against the pressure in the pressure
chamber 612 via the valve body 342.
[0203] A fitting hole 403 extends through the end wall 40, and an
accommodation cylinder 346 is fitted to the fitting hole 403. A
fixed iron core 364 is accommodated within the accommodation
cylinder 346. The movable iron core portion 345 is fitted into the
accommodation cylinder 346 in such a manner as to face the fixed
iron core 364. A coil 365 is arranged in an outer peripheral
surface of the accommodation cylinder 346. If the coil 365 is
excited, the movable iron core portion 345 is attracted to the
fixed iron core 364. The fixed iron core 364, the movable iron core
portion 345 and the coil 365 construct an electromagnetic solenoid
347, which serves as an electromagnetic driving portion.
[0204] The guide cylinder 45 surrounds the rotation axis 210. If
the valve body 342 comes close to the end wall 40, the volumetric
capacity of the pressure chamber 612 is reduced. The
electromagnetic solenoid 347, the valve body 342 and the first
return spring 47 construct the switch portion. The switch portion
is capable of switching the suction chamber 142, which is a portion
of the suction pressure zone within the compressor 10, to the
communication state, in which the suction chamber 142 communicates
with the front outlet 312 and the rear outlet 313 of the in-shaft
passage 31, and the shutoff state, in which the suction chamber 142
is shut off from the front outlet 312 and the rear outlet 313. The
first return spring 47 serves as the retaining spring retaining the
valve body 342 at the shutoff position.
[0205] In the state shown in FIG. 29B, a whole of the introduction
port 441 is located at a position exposed to the interior of the
suction chamber 142, and the in-shaft passage 31 communicates with
the suction chamber 142 via the cylinder interior 451 of the guide
cylinder 45, the cylinder interior 442 of the cylinder portion 44
and the introduction port 441. In the state shown in FIG. 29A, the
introduction port 441 is located at a position at which the entire
introduction port 441 enters the pressure recess 611, and the
in-shaft passage 31 is shut off from the suction chamber 142. FIG.
29B shows a state in which the valve body 342 is in a state of
being at the communication position connects the in-shaft passage
31 and the suction chamber 142, and FIG. 29A shows a state in which
the valve body 342 is in a state of being at the shutoff position,
at which the valve body 342 shuts off the in-shaft passage 31 and
the suction chamber 142.
[0206] In the case that the electromagnetic solenoid 347 is in the
magnetized state, the valve body 342 exists at the shutoff position
shown in FIG. 29A on the basis of the electromagnetic force of the
electromagnetic solenoid 347. The timing at which the
electromagnetic solenoid 347 is magnetized is the same as the case
of the twelfth embodiment. In the case that the operation of the
compressor 10 is in the stop state, the valve body 342 is retained
at the shutoff position shown in FIG. 29A on the basis of the
spring force of the first return spring 47. In other words, the
switch portion is capable of switching the suction chamber 142 to
the communication state [the state shown in FIG. 29B] in which the
suction chamber 142 communicates with the front outlet 312 and the
rear outlet 313 of the in-shaft passage 31, and the shutoff state
[the state shown in FIG. 29A] in which the suction chamber 142 is
shut off from the front outlet 312 and the rear outlet 313 of the
in-shaft passage 31.
[0207] If the electromagnetic solenoid 347 is magnetized before the
compressor 10 starts being operated, and the operation of the
compressor 10 is started thereafter, the starting impact is reduced
in the same manner as the case of the twelfth embodiment because
the valve body 342 exists at the shutoff position.
[0208] If the electromagnetic solenoid 347 is demagnetized after
starting the operation of the compressor 10, the valve body 342 is
released from the electromagnetic force of the electromagnetic
solenoid 347. Since the refrigerant within the cylinder interior
451 and the in-shaft passage 31 is drawn to the front compression
chamber 271 (refer to FIG. 21) and the rear compression chamber
281, a difference is generated between the pressure in the suction
chamber 142 and the pressure in the pressure chamber 612, on the
basis of the drawing operation. The spring force of the first
return spring 47 is set to such a magnitude that the first return
spring 47 is compressed by the differential pressure generated
between the pressure within the suction chamber 142 and the
pressure within the pressure chamber 612 at a time of operating the
compressor 10. Accordingly, the differential pressure generated
between the pressure in the suction chamber 142 and the pressure in
the pressure chamber 612 at a time of operating the compressor 10
overcomes the spring force of the first return spring 47, and
retains the valve body 342 at the communication position shown in
FIG. 29B.
[0209] The fifteenth embodiment has the same advantages as those of
the twelfth embodiment.
[0210] FIGS. 30A and 30B explain a sixteenth embodiment. The same
reference numerals are used in the same components as those of the
fifteenth embodiment.
[0211] The guide cylinder 45A fitted to the cylinder portion 44 of
the valve body 342 is formed as a closed-end cylindrical shape, and
is formed independently from the rear cylinder block 12, the rotary
shaft 21 and the like. The bottom wall of the guide cylinder 45A
comes into contact with the end surface 122 of the rear cylinder
block 12, and the guide cylinder 45A is fitted to the cylinder
portion 44 of the valve body 342 in such a manner as to be allowed
to move in the radial direction of the rotary shaft 21 with respect
to the rotary shaft 21. The communication port 452 is formed in the
bottom wall of the guide cylinder 45A in such a manner as to
connect the cylinder interior 451 of the guide cylinder 45A with
the in-shaft passage 31, and the first return spring 47 is arranged
between the bottom wall of the guide cylinder 45A and the piston
portion 43. In FIG. 30A, the valve body 342 is arranged at the
shutoff position, and the valve body 342 is arranged at the
communication position in FIG. 30B.
[0212] On the assumption that the refrigerant leaks through a
clearance between the valve body 342 and the cylinder 41 or a
clearance between the valve body 342 and the guide cylinder 45A at
a time when the valve body 342 exists at the shutoff position, the
effect of reducing the starting impact is lowered.
[0213] However, in the present embodiment, the guide cylinder 45A
is fitted to the cylinder portion 44 of the valve body 342 in such
a manner that the guide cylinder 45A is allowed to move in the
radial direction of the rotary shaft 21 with respect to the rotary
shaft 21. Accordingly, the axis 413 of the pressure recess 611 is
allowed to come into line with the axis 453 of the guide cylinder
45A. Therefore, it is possible to reduce the clearance between the
cylinder portion 44 of the valve body 342 and the cylinder 41 and
the clearance between the cylinder portion 44 of the valve body 342
and the guide cylinder 45A, and it is possible to prevent the
refrigerant from leaking along the peripheral surface of the
cylinder portion 44 of the valve body 342.
[0214] FIGS. 31A and 31B explain a seventeenth embodiment. The same
reference numerals are used in the same components as those of the
fifteenth embodiment.
[0215] The piston 69 is slidably fitted to the cylinder 41, and the
movable iron core portion 345 is integrally formed in the piston
69. The piston 69 defines the pressure chamber 612 within the
pressure recess 611. The transmission rod 70 is coupled to the
piston 69.
[0216] The small circumferential surface body 71, the large
circumferential surface body 72, the transmission rod 70 and the
piston 69 construct the valve body defining the pressure chamber
612 within the pressure recess 611.
[0217] FIG. 31A shows a state in which the small circumferential
surface body 71 closes the front outlet 312, and the large
circumferential surface body 72 closes the rear outlet 313, and the
front outlet 312 and the rear outlet 313 are shut off from the
in-shaft passage 31A. FIG. 31B shows a state in which the small
circumferential surface body 71 opens the front outlet 312, and the
large circumferential surface body 72 opens the rear outlet 313,
and the front outlet 312 and the rear outlet 313 communicate with
the in-shaft passage 31A. If the electromagnetic solenoid 347 is
excited, the small circumferential surface body 71 and the large
circumferential surface body 72 are arranged at the shutoff
position shown in FIG. 31A from the communication position shown in
FIG. 31B on the basis of the spring force of the first return
spring 73. The first return spring 73 serves as the retaining
spring retaining the small circumferential surface body 71 and the
large circumferential surface body 72 at the shutoff position.
[0218] The seventeenth embodiment has the same advantages as those
of the twelfth embodiment. Further, in the seventeenth embodiment,
since the refrigerant which can flow in the front compression
chamber 271 and the rear compression chamber 281 at a time when the
small circumferential surface body 71 and the large circumferential
surface body 72 exist at the shutoff position is constituted only
by the refrigerant within the front outlet 312 and the rear outlet
313, and within the front communication passage 32 and the rear
communication passage 33, the effect of reducing the starting
impact is more noticeable than the case of the twelfth
embodiment.
[0219] Further, if the piston 69 is structured such as to be
relatively rotatable with respect to the transmission rod 70, it is
possible to prevent the first return spring 73 from relatively
rotating with respect to the rotary shaft 21. Accordingly, it is
possible to avoid the abrasion and damage of the first return
spring 73 or the rotary shaft 21 caused by the relative rotation
between the first return spring 73 and the rotary shaft 21.
Alternatively, the large circumferential surface body 72 may be
structured such as to be relatively rotatable with respect to the
first return spring 73.
[0220] FIGS. 32A and 32B explain an eighteenth embodiment. The same
reference numerals are used in the same components as those of the
seventeenth embodiment.
[0221] As shown in FIG. 32A, in the case that the large
circumferential surface body 72 is located at the position at which
it closes the rear outlet 313, the circular plate 74 exists at an
upstream side of the front outlet 312 within the in-shaft passage
31A. Accordingly, the refrigerant in the in-shaft passage 31A
cannot flow in the front compression chamber 271 via the front
outlet 312. As shown in FIG. 32B, in the case that the large
circumferential surface body 72 is located at the position at which
it opens the rear outlet 313, the circular plate 74 exists in a
downstream side of the front outlet 312 within the in-shaft passage
31A. Accordingly, the refrigerant in the in-shaft passage 31A can
flow in the front compression chamber 271 via the front outlet 312.
If the electromagnetic solenoid 347 is excited, the cylinder 75 is
arranged at the shutoff position shown in FIG. 32A from the
communication position shown in FIG. 32B, on the basis of the
spring force of the first return spring 73. The circular plate 74,
the large circumferential surface body 72, the transmission rod 70,
and the piston 69 construct a valve body which defines the pressure
chamber 612 within the pressure recess 611.
[0222] The eighteenth embodiment has the same advantages as those
of the seventeenth embodiment.
[0223] FIGS. 33A and 33B explain a nineteenth embodiment. The same
reference numerals are used in the same components as those of the
seventeenth embodiment.
[0224] The cylinder 75 can slide within the in-shaft passage 31A in
a state in which the angular pin 76 is inserted to an end wall 752
of the cylinder 75. The cylinder 75 and the piston 69 construct a
valve body which defines the pressure chamber 612 within the
pressure recess 611.
[0225] FIG. 33B shows a state in which the small-diameter
cylindrical portion 77 closes the front outlet 312, and shows a
state in which the large-diameter cylindrical portion 78 closes the
rear outlet 313. Accordingly, the front outlet 312 and the outlet
313 are shut off from the cylinder interior 750 of the cylinder 75.
FIG. 33A shows a state in which the communication port 771 of the
small-diameter cylindrical portion 77 communicates with the front
outlet 312, and shows a state in which the communication port 781
of the large-diameter cylindrical portion 78 communicates with the
rear outlet 313, and the front outlet 312 and the rear outlet 313
communicate with the cylinder interior 750. If the electromagnetic
solenoid 347 is excited, the cylinder 75 is arranged at the shutoff
position shown in FIG. 33B from the communication position shown in
FIG. 33A, on the basis of the spring force of the first return
spring 73.
[0226] The nineteenth embodiment has the same advantages as those
of the seventeenth embodiment.
[0227] FIG. 34 shows a compressor 10A having one headed pistons 95
in accordance with a twentieth embodiment. The electromagnetic
solenoid 248 and the valve body 242 are provided in the rear
housing member 14. The twentieth embodiment has the same advantages
as those of the twelfth embodiment.
[0228] The embodiments mentioned above may be modified as
follows.
[0229] In FIGS. 3 and 4, the discharge refrigerant fed to the
working pressure chamber 412 may be taken from a portion of the
external refrigerant circuit in the upstream side of the heat
exchanger 37.
[0230] The electromagnetic three-way valve 48 shown in FIGS. 12 and
13 may be incorporated by being coupled to the rear housing member
14.
[0231] The electromagnetic on-off valve 67 in FIGS. 8 to 9A may be
incorporated in the rear housing member 14. Further, the
electromagnetic on-off valve 67A in FIGS. 10 to 11A may be
incorporated in the rear housing member 14.
[0232] The check valve 68 in FIGS. 8 to 11A may be incorporated in
the housing of the compressor 10.
[0233] The oil separator 79 in FIGS. 17 to 18B may be incorporated
in the housing of the compressor 10.
[0234] The valve body 42 may be arranged at the communication
position in the case of magnetizing the electromagnetic three-way
valve 48 in FIGS. 3 and 4, and the valve body 42 may be arranged at
the shutoff position in the case of demagnetizing the
electromagnetic three-way valve 48.
[0235] The valve body 242 may be arranged at the communication
position in the case of magnetizing the electromagnetic solenoid
248 in FIGS. 23 and 24, and the valve body 242 may be arranged at
the shutoff position in the case of demagnetizing the
electromagnetic solenoid 248.
[0236] The valve body 342 may be arranged at the communication
position in the case of magnetizing the electromagnetic solenoid
347 in FIGS. 29A and 29B, and the valve body 342 may be arranged at
the shutoff position in the case of demagnetizing the
electromagnetic solenoid 347.
[0237] The pressure chamber 262 in FIGS. 23 and 24 may be always
shut off from the suction chamber 142, and the pressure chamber 262
may communicate with the atmospheric air.
[0238] Each of the first rotary valve 35 and the second rotary
valve 36 may be formed independently from the rotary shaft 21.
* * * * *