U.S. patent application number 10/743229 was filed with the patent office on 2004-10-07 for variable displacement mechanism for scroll type compressor.
Invention is credited to Iguchi, Masao, Iwasa, Jiro, Kawaguchi, Masahiro, Sakamoto, Masaya, Yamanouchi, Akihito.
Application Number | 20040197204 10/743229 |
Document ID | / |
Family ID | 32816157 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040197204 |
Kind Code |
A1 |
Yamanouchi, Akihito ; et
al. |
October 7, 2004 |
Variable displacement mechanism for scroll type compressor
Abstract
A variable displacement mechanism for a scroll type compressor
includes a by-pass passage, a valve chamber, a valve plate and an
actuator. The by-pass passage serves to interconnect a compression
chamber in a process of volume reduction with a suction pressure
region and includes a first valve hole. The valve chamber serves to
communicate with the first valve hole and forms a valve seat
surface around an opening of the first valve hole. The valve plate
has an end surface that faces the valve seat surface. The valve
plate is arranged in the valve chamber so as to selectively move
between an open position, where the end surface is separated from
the valve seat surface to open the first valve hole, and a close
position, where the end surface contacts the valve seat surface to
close the first valve hole. The actuator serves to actuate the
valve plate.
Inventors: |
Yamanouchi, Akihito;
(Kariya-shi, JP) ; Iguchi, Masao; (Kariya-shi,
JP) ; Iwasa, Jiro; (Kariya-shi, JP) ;
Sakamoto, Masaya; (Kariya-shi, JP) ; Kawaguchi,
Masahiro; (Kariya-shi, JP) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
ONE LIBERTY PLACE, 46TH FLOOR
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Family ID: |
32816157 |
Appl. No.: |
10/743229 |
Filed: |
December 22, 2003 |
Current U.S.
Class: |
417/310 |
Current CPC
Class: |
F04C 23/008 20130101;
F04C 28/26 20130101; F04C 18/0215 20130101 |
Class at
Publication: |
417/310 |
International
Class: |
F04B 049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2002 |
JP |
2002-379752 |
Claims
What is claimed is:
1. A variable displacement mechanism in a scroll type compressor
having a movable scroll member and a fixed scroll member, the
movable scroll member and the fixed scroll member defining
compression chambers therebetween, the compression chambers
reducing in volume as the compression chambers are moved radially
and inwardly by orbiting the movable scroll member relative to the
fixed scroll member, whereby gas is compressed, a suction pressure
region being defined in the scroll type compressor, the variable
displacement mechanism comprising: a by-pass passage provided for
interconnecting the compression chamber in a process of volume
reduction with the suction pressure region, the by-pass passage
including a first valve hole; a valve chamber provided for
communicating with the first valve hole, the valve chamber forming
a valve seat surface around an opening of the first valve hole; a
valve plate having an end surface that faces the valve seat
surface, the valve plate being arranged in the valve chamber so as
to selectively move between an open position, where the end surface
is separated from the valve seat surface to open the first valve
hole, and a close position, where the end surface contacts the
valve, seat surface to close the first valve hole; and an actuator
actuating the valve plate.
2. The variable displacement mechanism according to claim 1,
wherein the by-pass passage is configured to continuously
interconnect the compression chamber with the suction pressure
region until the compression chamber in the process of volume
reduction reduces in volume to a predetermined value in a state
where the valve plate is located at the open position.
3. The variable displacement mechanism according to claim 2,
wherein the first valve hole partially constitutes the by-pass
passage on a side of the compression chamber with respect to the
valve chamber, the first valve hole being plurally provided, each
of the first valve holes interconnecting the compression chamber
with the valve chamber at a position that is different from each
other, different portions of the end surface of the valve plate
simultaneously opening and closing a plurality of the first valve
holes.
4. The variable displacement mechanism according to claim 3,
wherein the valve plate simultaneously opens and closes a second
valve hole that partially constitutes the by-pass passage on a side
of the suction pressure region with respect to the valve
chamber.
5. The variable displacement mechanism according to claim 1,
wherein the fixed scroll member includes a fixed base plate and a
fixed spiral wall that extends from the fixed base plate, the valve
chamber being defined on a side of a back surface of the fixed base
plate, the valve seat surface of the valve chamber being formed by
the fixed base plate, the valve plate being arranged along the
fixed base plate.
6. The variable displacement mechanism according to claim 5,
wherein a discharge chamber is defined in the scroll type
compressor, the valve plate having one of a complete annular shape
and an incomplete annular shape that is an annular shape of which a
part is removed therefrom, a discharge passage being formed at a
center of the valve plate for discharging the compressed gas from
the compression chamber to the discharge chamber.
7. The variable displacement mechanism according to claim 1,
wherein a seal member is arranged on one of the end surface of the
valve plate and the valve seat surface for sealing the by-pass
passage in a state where the valve plate is located at the close
position.
8. The variable displacement mechanism according to claim 1,
wherein a discharge pressure region is defined in the scroll type
compressor, the valve plate being arranged to divide the valve
chamber into a communication chamber on the side of the first valve
hole and a back pressure chamber on a side opposite to the side of
the first valve hole, the communication chamber partially
constituting the by-pass passage, the actuator including an urging
spring that urges the valve plate toward the open position, a first
control passage that interconnects the back pressure chamber with
the discharge pressure region, and a control valve that regulates
an opening degree of the first control passage based on an external
command.
9. The variable displacement mechanism according to claim 8,
wherein the valve plate is located at the close position when the
control valve opens the first control passage, the valve plate
being located at the open position when the control valve closes
the first control passage.
10. The variable displacement mechanism according to claim 9,
wherein the actuator also includes a second control passage that
interconnects the suction pressure region with the back pressure
chamber, the control valve regulating an opening degree of the
second control passage based on the external command, the valve
plate being located at the open position when the control valve
opens the second control passage.
11. The variable displacement mechanism according to claim 1,
wherein the scroll type compressor is used for a vehicle air
conditioner, the scroll type compressor being a hybrid type that is
selectively driven by power from an engine for traveling a vehicle
and by power from an internal electric motor.
12. A scroll type compressor that defines a suction pressure region
comprising: a movable scroll member; a fixed scroll member,
compression chambers being defined by the movable scroll member and
the fixed scroll member, the compression chambers reducing in
volume as the compression chambers are moved radially and inwardly
by orbiting the movable scroll member relative to the fixed scroll
member, whereby gas is compressed; and a variable displacement
mechanism including: a by-pass passage provided for interconnecting
the compression chamber with the suction pressure region, the
by-pass passage including a first valve hole; a valve chamber
provided for communicating with the first valve hole, the valve
chamber forming a valve seat surface around an opening of the first
valve hole; a valve plate having an end surface that faces the
valve seat surface, the valve plate being arranged in the valve
chamber so as to selectively move between an open position, where
the end surface is separated from the valve seat surface to open
the first valve hole, and a close position, where the end surface
contacts the valve seat surface to close the first valve hole; and
an actuator actuating the valve plate.
13. The scroll type compressor according to claim 12, wherein the
by-pass passage is configured to continuously interconnect the
compression chamber with the suction pressure region until the
compression chamber in the process of volume reduction reduces in
volume to a predetermined value in a state where the valve plate is
located at the open position.
14. The scroll type compressor according to claim 13, wherein the
first valve hole partially constitutes the by-pass passage on a
side of the compression chamber with respect to the valve chamber,
the first valve hole being plurally provided, each of the first
valve holes interconnecting the compression chamber with the valve
chamber at a position that is different from each other, different
portions of the end surface of the valve plate simultaneously
opening and closing a plurality of the first valve holes.
15. The scroll type compressor according to claim 14, wherein the
valve plate simultaneously opens and closes a second valve hole
that partially constitutes the by-pass passage on a side of the
suction pressure region with respect to the valve chamber.
16. The scroll type compressor according to claim 12, wherein the
fixed scroll member includes a fixed base plate and a fixed spiral
wall that extends from the fixed base plate, the valve chamber
being defined on a side of a back surface of the fixed base plate,
the valve seat surface of the valve chamber being formed by the
fixed base plate, the valve plate being arranged along the fixed
base plate.
17. The scroll type compressor according to claim 16, wherein a
discharge chamber is defined in the scroll type compressor, the
valve plate having one of a complete annular shape and an
incomplete annular shape that is an annular shape of which a part
is removed therefrom, a discharge passage being formed at a center
of the valve plate for discharging the compressed gas from the
compression chamber to the discharge chamber.
18. The scroll type compressor according to claim 12, wherein a
seal member is arranged on one of the end surface of the valve
plate and the valve seat surface for sealing the by-pass passage in
a state where the valve plate is located at the close position.
19. The scroll type compressor according to claim 12, wherein a
discharge pressure region is defined in the scroll type compressor,
the valve plate is arranged to divide the valve chamber into a
communication chamber on the side of the first valve hole and a
back pressure chamber on a side opposite to the side of the first
valve hole, the communication chamber partially constituting the
by-pass passage, the actuator including an urging spring that urges
the valve plate toward the open position, a control passage that
interconnects the back pressure chamber with the discharge pressure
region, and a control valve that regulates an opening degree of the
control passage based on an external command.
20. The scroll type compressor according to claim 12, wherein the
scroll type compressor is used for a vehicle air conditioner, the
scroll type compressor being a hybrid type that is selectively
driven by power from an engine for traveling a vehicle and by power
from an internal electric motor.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a scroll type compressor
for use in a vehicle air conditioner and more particularly to a
variable displacement mechanism for varying the displacement of the
scroll type compressor.
[0002] A variable displacement mechanism of such type is disclosed
in Japanese Unexamined Patent Publication No. 2001-32787. A
compression chamber communicates with a suction pressure region
through a by-pass passage in a process of volume reduction. A spool
valve opens and closes the by-pass passage to vary the displacement
of the scroll type compressor.
[0003] In the spool valve, a spool is slidably accommodated in a
cylinder. The spool includes a valve portion and a rod portion. The
valve portion has an outer diameter that is substantially equal to
an inner diameter of the cylinder. Also, the valve portion opens
and closes the by-pass passage. The rod portion has an outer
diameter that is smaller than the inner diameter of the cylinder,
and partially constitutes the by-pass passage.
[0004] However, in the variable displacement, the spool is formed
to open and close a port that is open at an inner circumferential
surface of the cylinder (an inner surface of the cylinder) by the
valve portion (a column) of the spool so that it is difficult to
arrange a seal member at the valve portion. Therefore, the valve
portion of the spool contacts the inner circumferential surface of
the cylinder so as to prevent refrigerant gas from leaking from the
spool valve.
[0005] A small clearance between the valve portion of the spool and
the inner circumferential surface of the cylinder effectively
suppresses the leakage of the refrigerant gas from the by-pass
passage. However, as the clearance between the valve portion of the
spool and the inner circumferential surface of the cylinder is
relatively small, sliding resistance increases between the spool
and the cylinder. As a result, problems, such as deterioration in
response to displacement variation and enlargement of an actuator
for actuating the spool, occur.
[0006] Accordingly, in a prior art, in view of suppressing the rise
of cost for manufacturing a highly accurate clearance, the
clearance between the valve portion of the spool and the inner
circumferential surface of the cylinder is relatively large. Then,
for example, even though the scroll type compressor is tried to
operate at a maximum displacement by closing the by-pass passage, a
desired maximum displacement cannot be achieved due to the leakage
of the refrigerant gas from the spool (the by-pass passage).
Namely, performance of the scroll type compressor deteriorates.
SUMMARY OF THEE INVENTION
[0007] The present invention provides a variable displacement
mechanism that reliably seals a by-pass passage for a scroll type
compressor.
[0008] In accordance with the present invention, in a scroll type
compressor having a movable scroll member and a fixed scroll
member, the movable scroll member and the fixed scroll member
define compression chambers therebetween. The compression chambers
reduce in volume as the compression chambers are moved radially and
inwardly by orbiting the movable scroll member relative to the
fixed scroll member. Thus gas is compressed. A suction pressure
region is defined in the scroll type compressor. A variable
displacement mechanism for the scroll type compressor includes a
by-pass passage, a valve chamber, a valve plate and an actuator.
The by-pass passage serves to interconnect the compression chamber
in a process of volume reduction with the suction pressure region
includes a first valve hole. The valve chamber serves to
communicate with the first valve hole and forms a valve seat
surface around an opening of the first valve hole. The valve plate
has an end surface that faces the valve seat surface. The valve
plate is arranged in the valve chamber so as to selectively move
between an open position, where the end surface is separated from
the valve seat surface to open the first valve hole, and a close
position, where the end surface contacts the valve seat surface to
close the first valve hole. An actuator serves to actuate the valve
plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] 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:
[0010] FIG. 1 is a longitudinal cross-sectional view of a hybrid
compressor according to a preferred embodiment of the present
invention;
[0011] FIG. 2 is a cross-sectional view of the hybrid compressor
taken along the line I-I in FIG. 1;
[0012] FIG. 3A is a partially enlarged cross-sectional view that
corresponds to FIG. 1 in a state where a valve plate is located at
an open position; and
[0013] FIG. 3B is a partially enlarged cross-sectional view that
corresponds to FIG. 1 in a state where the valve plate is located
at a close position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] A preferred embodiment according to the present invention
will be described. The preferred embodiment applies the present
invention to a hybrid compressor C that is a scroll type. The left
and right sides of FIG. 1 respectively correspond to the front and
rear sides the compressor C.
[0015] The compressor C will be schematically described. As shown
in FIG. 1, the compressor C constitutes a refrigerating cycle of a
vehicle air conditioner and includes a housing 11, a compression
mechanism 12, an electric motor 21 and a power transmission
mechanism 22. The compression mechanism 12 and the electric motor
21 are accommodated in the housing 11. The power transmission
mechanism 22 is arranged on an outer wall of the housing 11. The
compression mechanism 12 is a scroll type and has a structure to
vary a displacement of the compressor C. The power transmission
mechanism 22 receives power from an engine (internal combustion) E
for traveling a vehicle.
[0016] The compressor C is selectively driven by one of power from
the engine E through the power transmission mechanism 22 and power
from the electric motor 21. Since the compressor C includes the
electric motor 21, air conditioning (cooling) is capable of being
continuously conducted even when, the engine E is in a stopped
state. Therefore, the vehicle air conditioner in the present
preferred embodiment is particularly suitable for an idle stop
vehicle and a hybrid vehicle.
[0017] The compressor C will be now described in detail. As shown
in FIG. 1, the housing 11 includes a casing 11a and a cover 11b.
The casing 11a has a cylindrical shape with a bottom that
corresponds to the front side. The cover 11b is fixed to the rear
end of the casing 11a. A rotary shaft 13 is rotatably arranged in
the housing 11. A through hole 34 is formed at the center of the
bottom of the casing 11a of the housing 11 so as to extend
therethrough. The front end of the rotary shaft 13 is interposed
into the through hole 34. The front end of the rotary shaft 13 is
rotatably supported by the housing 11 through a bearing 35 in the
through hole 34. A lip seal 37 is arranged on the front end of the
rotary shaft 13 in the housing 11 for sealing the rotary-shaft
13.
[0018] A shaft support member 31 is fixed on the rear end side of
the casing 11a in the housing 11. A through hole 31a is formed at
the center of the shaft support member 31 so as to extend
therethrough. The rear end of the rotary shaft 13 is interposed
into the through hole 31a of the shaft support member 31 and is
rotatably supported by the shaft support member 31 through a
bearing 32 in the through hole 31a.
[0019] The power transmission mechanism 22 includes a pulley 17 and
an electromagnetic clutch 18. The pulley 17 is rotatably supported
at the outside of the housing 11 and transmits the power from the
engine E to the rotary shaft 13. When the electromagnetic clutch 18
is switched on (energized), the electromagnetic clutch 18 permits
power transmission from the pulley 17 to the rotary shaft 13. When
the electromagnetic clutch 18 is switched off (de-energized), the
electromagnetic clutch 18 blocks the power transmission.
[0020] A stator 15 is provided on the inner circumferential surface
of the casing 11a of the housing 11 and is located on the front
side of the housing 11. A rotor 14 is fixed to the rotary shaft 13
in the housing 11 so as to be located inside the stator 15. The
electric motor 21 includes the stator 15 and the rotor 14. The
electric motor 21 integrally rotates the rotor 14 and the rotary
shaft 13 by supplying electric power to the stator 15.
[0021] A fixed scroll member 41 is fixedly accommodated at the
opening end of the casing 11a in the housing 11. The fixed scroll
member 41 includes a fixed base plate 61 that has a disc-shape, an
outer circumferential wall 62 that has a cylindrical shape and a
fixed spiral wall 63. The outer circumferential wall 62 extends
from the outer periphery of the fixed base plate 61. The fixed
spiral wall 63 extends from the fixed base plate 61 inside the
outer circumferential wall 62. The end surface of the outer
circumferential wall 62 is joined to the rear surface of the shaft
support member 31.
[0022] A crankshaft 43 is provided at the rear end surface of the
rotary shaft 13 and is offset from an axis L of the rotary shaft 13
in an eccentric direction. The crankshaft 43 is inserted in a
bushing 51. A movable scroll member 42 is supported by the bushing
51 through a bearing 52 so as to face the fixed scroll member 41
and so as to rotate relative to the fixed scroll member 41. The
movable scroll member 42 includes a movable base plate 65 that has
a disc-shape and a movable spiral wall 66 that extends from the
movable base plate 65 toward the fixed scroll member 41.
[0023] The movable spiral wall 66 of the movable scroll member 42
is engaged with the fixed spiral wall 63 of the fixed scroll member
41. The end surfaces of the fixed and movable spiral wall 63 and 66
respectively contact the movable and fixed base plates 65 and 61.
Therefore, the fixed base plate 61 and the fixed spiral wall 63 of
the fixed scroll member 41 and the movable base plate 65 and the
movable spiral wall 66 of the movable scroll member 42 define
compression chambers 67.
[0024] A self-rotation preventing mechanism 68 is arranged between
the movable base plate 65 of the movable scroll member 42 and the
shaft support member 31. The self-rotation preventing mechanism 68
is constituted of a plurality of cylindrical recesses 68a and a
plurality of pins 68b. The cylindrical recesses 68a are formed at
the back surface (the front surface) of the movable base plate 65.
The pins 68b are mounted on the rear end surface of the shaft
support member 31 and is loosely fitted in the corresponding
cylindrical recesses 68a.
[0025] A suction chamber 69 or a suction pressure region is defined
between the outer circumferential wall 62 of the fixed scroll
member 41 and the outer circumferential portion of the movable
spiral wall 66 of the movable scroll member 42. An inlet 50 is
formed in the outer circumferential wall of the casing 11 a of the
housing 11 so as to correspond to an accommodating space for the
electric motor 21. An external conduit is connected to the inlet 50
and leads to a heat exchanger on a low-pressure side in an external
refrigerating circuit (not shown). A suction passage 39 is formed
in the outer circumferential portion of the shaft support member 31
in the housing 11 for interconnecting the accommodating space for
the electric motor 21 with the suction chamber 69. Therefore,
low-pressure refrigerant gas from the external refrigerating
circuit is introduced into the suction chamber 69 through the inlet
50, the accommodating space for the electric motor 21 and the
suction passage 39. The suction refrigerant gas with a relatively
low temperature passes near the electric motor 21. Therefore, heat
environmental of the electric motor 21 is satisfactory.
[0026] A first accommodating recess 61b is formed on a part of a
back surface 61a of the fixed base plate 61 of the fixed scroll
member 41 in the range from the adjacent center portion to the
adjacent outer periphery. The first accommodating recess 61b is
closed by the cover 11b, thereby defining a discharge chamber 70 as
a discharge pressure region between the fixed scroll member 41 and
the cover 11b in the housing 11. An outlet 53 is formed in the
cover 11b. An external conduit is connected to the discharge
chamber 70 through the outlet 53 and leads to a heat exchanger on a
high-pressure side in the external refrigerating circuit (not
shown).
[0027] A discharge hole 61c as a discharge passage is formed in the
center of the fixed base plate 61 of the fixed scroll member 41 so
as to extend therethrough in a direction of the axis L and
interconnects the compression chamber 67 near the center of the
fixed base plate 61 with the discharge chamber 70. A discharge
valve 55 constituted of a reed valve is arranged at the fixed
scroll member 41 in the discharge chamber 70 for opening and
closing the discharge hole 61c. A retainer 56 is fixed to the fixed
scroll member 41 in the discharge chamber 70 to restrict the
opening degree of the discharge valve 55.
[0028] When the rotary shaft 13 is rotatively driven by the engine
E or the electric motor 21, the movable scroll member 42 orbits
around the axis of the fixed scroll member 41 (the axis L of the
rotary shaft 13) through the crankshaft 43 in the compression
mechanism 12. At this time, the self-rotation preventing mechanism
68 prevents the movable scroll member 42 from self-rotating while
allowing the movable scroll member 42 to orbit around the axis of
the fixed scroll member 41.
[0029] As the compression chambers 67 are moved radially and
inwardly by the orbital movement of the movable scroll member 42
relative to the fixed scroll member 41, the compression chambers 67
reduce in volume. Thereby, the low-pressure refrigerant gas
introduced from the suction chamber 69 into the compression
chambers 67 is compressed. After compression, the high-pressure
refrigerant gas is discharged from the discharge hole 61c into the
discharge chamber 70 through the discharge valve 55.
[0030] A variable displacement mechanism of the compressor C will
be now described. As shown in FIGS. 2 and 3A, a second
accommodating recess 61d is formed on the back surface 61a of the
fixed base plate 61 of the fixed scroll member 41 The second
accommodating recess 61d has a horseshoe shape (an annular shape of
which a part is removed therefrom) so as to avoid the first
accommodating recess 61b. The opening of the second accommodating
recess 61d is closed by the end surface of the cover 11b, thereby
defining a valve chamber 45. A valve plate 46 is movably
accommodated in the valve chamber 45.
[0031] The valve plate 46 has a planar shape and a horseshoe shape
so as to be fitted in the second accommodating recess 61d. In other
word, the discharge hole 61c is arranged at the center (a through
hole) of the valve plate 46, and the valve plate 46 is formed so as
to avoid the discharge hole 61c. An O-ring 47 is attached on the
outer circumferential surface of the valve plate 46. The valve
plate 46 is slidable relative to the inner circumferential surface
of the valve chamber 45 through the O-ring 47.
[0032] The valve plate 46 is arranged to divide the valve chamber
45 into a communication chamber 48 on the side of the fixed scroll
member 41 and a back pressure chamber 49 on a side of the cover
11b. The O-ring 47 on the valve plate 46 blocks between the
communication chamber 48 and the back pressure chamber 49. A valve
seat surface 48a having a horseshoe-shape is formed in the fixed
base plate 61 in the communication chamber 48 so as to face a plate
surface (hereinafter referred to as a front end surface) 46a of the
valve plate 46, which has a horseshoe-shape. The valve plate 46 is
arranged along the fixed base plate 61 in such a manner that the
front end surface 46a of the valve plate 46 is parallel to the back
surface 61a of the fixed base plate 61.
[0033] A first valve hole 61 e is formed in the fixed base plate 61
of the fixed scroll member 41 so as to extent therethrough in the
direction of the axis L. One end of the first valve hole 61e is
open to the compression chamber 67 in a process of volume
reduction, and the other end of the first valve hole 61e is open to
the communication chamber 48 at the valve seat surface 48a of the
fixed base plate 61. The first valve hole 61e is plurally provided.
Each of the first valve holes 61e interconnects the compression
chamber 67 with the communication chamber 48 at a position that is
different from each other. The first valve holes 61e communicate
with the compression chamber 67 in the process of volume reduction
by turns during time when the compression chamber 67 at an initial
position of volume reduction that has a maximum volume reduces in
volume to a predetermined value (e.g. 20% of the maximum
volume).
[0034] A second valve hole 61f is formed in the fixed base plate 61
of the fixed scroll member 41 so as to extend therethrough in the
direction of the axis L. The second valve hole 61f interconnects
the communication chamber 48 with the suction chamber 69. The
second valve hole 61f is open to the communication chamber 48 at a
position that is different from the first valve holes 61e at the
valve seat surface 48a of the fixed base plate 61. In the present
preferred embodiment, the first valve holes 61e, the second, valve
hole 61f and communication chamber 48 constitute a by-pass passage
that interconnects the compression chamber 67 in the process of
volume reduction with the suction chamber 69.
[0035] The valve plate 46 selectively moves between an open
position, where the front end surface 46a of the valve plate 46 is
separated from the valve seat surface 48a in the communication
chamber 48 to simultaneously open the first valve holes 61e and the
second valve hole 61f, and a close position, where the front end
surface 46a of the valve plate 46 contacts the valve seat surface
48a to simultaneously close the first valve holes 61e and the
second valve hole 61f. The front end surface 46a of the valve plate
46 is provided by a rubber coat 46b, or a seal member, that is
applied to the valve plate 46. Therefore, when the valve plate 46
is located at the close position, the front end surface 46a
reliably seals the first valve holes 61e and the second valve hole
61f due to elastic deformation of the rubber coat 46b.
[0036] An actuator for actuating the valve plate 46 is constituted
of an urging spring 57, a control valve 58, and first, second and
third passages 71 through 73. The urging spring 57 is arranged in
the communication chamber 48. The control valve 58 is constituted
of an electromagnetic three-way valve. The first passage 71
interconnects the discharge chamber 70 with the control valve 58.
The second passage 72 interconnects the back pressure chamber 49
with the control valve 58. The third passage 73 interconnects the
suction chamber 69 with the control valve 58. The control valve 58
is symbolized in FIGS. 1, 3A and 3B for easy understanding. The
first and second passages 71 and 72 correspond to a first control
passage, and the second and third passages 72 and 73 correspond to
a second control passage.
[0037] A plurality of the urging spring 57 is arranged between the
valve seat surface 48a of the fixed base plate 61 and the front end
surface 46a of the valve plate 46 so as to avoid the openings of
the first and second valve holes 61e and 61f. The valve plate 46 is
urged by the spring force of the urging spring 57 in a direction in
which the front end surface 46a is separated from the valve seat
surface 48a The first, second and third passages 71 through 73
respectively communicate with first, second and third ports 58a,
58b and 58c of the control valve 58.
[0038] In the present preferred embodiment, the first passage 71,
an internal 1o passage of the control valve 58 and the second
passage 72 constitute a control passage that interconnects the back
pressure chamber 49 with the discharge chamber 70. The control
valve 58 opens and closes the control passage based on an external
command. Namely, the communication with the second passage 72 is
switched between the first and third passages 71 and 73 by
energizing and de-energizing a solenoid 58d based on the external
command. In other word, the communication with the back pressure
chamber 49 is switched between the suction chamber 69 and the
discharge chamber 70 by energizing and de-energizing the solenoid
58d.
[0039] For example, as shown in FIG. 3B, when the solenoid 58d is
de-energized, the first passage 71 communicates with the second
passage 72 through the control valve 58. Therefore, the
high-pressure refrigerant gas in the discharge chamber 70 is
discharged into the back pressure chamber 49 through the first
passage 71, the control valve 58 and the second passage 72. Since
the third passage 73 is closed by the control valve 58 in this
state, the refrigerant gas in the back pressure chamber 49 is not
discharged into the suction chamber 69. Consequently, the pressure
in the back pressure chamber 49 increases, and the valve plate 46
moves to the close position against the spring force of the urging
spring 57 and force based on the pressure in the communication
chamber 48 so that the first and second valve holes 61e and 61f are
closed.
[0040] In a state where the first and second valve holes 61e and
61f are closed, the compression chamber 67 in the process of volume
reduction does not communicate with the suction chamber 69. Also,
the compression chamber 67 substantially completely compresses the
refrigerant gas so that the displacement of the compression
mechanism 12 becomes the maximum. For example, when the engine E is
selected to drive the compression mechanism 12, the compression
mechanism 12 performs the maximum displacement. Therefore, even
though the rotational speed of the rotary shaft 13 is relatively
small due to an idling state of the engine E, the compression
mechanism 12 ensures a large amount of the discharged refrigerant
gas per unit time, that is, the compression mechanism 12 performs
relatively high cooling capacity.
[0041] Also, as shown in FIG. 3A, when the solenoid 58d is
energized, the second passage 72 communicates with the third
passage 73 through the control valve 58. Therefore, the refrigerant
gas in the back pressure chamber 49 is discharged into the suction
chamber 69 through the second passage 72, the control valve 58 and
the third passage 73. Since the first passage 71 is closed by the
control valve 58 in this state, the high-pressure refrigerant gas
in the discharge chamber 70 is not discharged into the back
pressure chamber 49. Consequently, the pressure in the back
pressure chamber 49 falls, and the valve plate 46 moves to the open
position by the spring force of the urging spring 57 and force
based on the pressure in the communication chamber 48 so that the
first and second valve holes 61e and 61f are opened.
[0042] In a state where the first and second valve holes 61e and
61f are opened, the compression chamber 67 in the process of volume
reduction continuously communicates with the suction chamber 69
through any one of the first valve holes 61e and through the
communication chamber 48 and the second valve hole 61f until the
compression chamber 67 reduces in volume to the,.predetermined
value. Therefore, the compression chamber 67 does not completely
compress the refrigerant gas so that the displacement of the
compression mechanism 12 is reduced from the maximum. For example,
when the electric motor 21 is selected to drive the compression
mechanism 12, the displacement of the compression mechanism 12 is
reduced from the maximum. As the displacement of the compression
mechanism 12 is reduced, torque required for driving the
compression mechanism 12 becomes small. Therefore, the compressor C
is downsized by reducing the size of electric motor 21.
[0043] In the present preferred embodiment, following advantageous
effects are obtained.
[0044] (1) The opening and closing of the by-pass passages 48, 61e
and 61f, that is, the variation of the displacement of the
compressor C, is performed by contacting the front end surface 46a
of the valve plate 46 with the valve seat surface 48a and
separating the front end surface 46a of the valve plate 46 from the
valve seat surface 48a. Therefore, in a state where the valve plate
46 is located at the close position, the contact of the front end
surface 46a of the valve plate 46 with the valve seat surface 48a
seals the by-pass passages 48, 61e and 61f. For example, in
Japanese Unexamined Patent Publication No. 2001-32787, a valve
portion (a column) of a spool opens and closes a port that is open
at an inner circumferential surface of a cylinder (an inner surface
of the cylinder). In comparison to this structure, closely contact
between the front end surface 46a of the valve plate 46 and the
valve seat surface 48a can be easily enhanced without inhibiting
mobility of the valve plate 46. Therefore, sealing the by-pass
passages 48, 61e and 61f in a state where the valve plate 46 is
located at the close position can be ensured. Also, deterioration
of performance of the compress C due to the leakage of the
refrigerant gas from the by-pass passages 48, 61e and 61f is
suppressed.
[0045] (2) The by-pass passages 48, 61e and 61f are formed so as to
continuously interconnect the compression chamber 67 with the
suction chamber 69 until the compression chamber 67 in the process
of volume reduction reduces in volume to the predetermined value in
a state where the valve plate 46 is located at the open position.
Namely, when the valve plate 46 is located at the open position,
the compression chamber 67 does not completely compress until the
compression chamber 67 reduces in volume to the predetermined value
after 1o the start of volume reduction. Accordingly, for example,
in comparison to a variable displacement mechanism that changes the
displacement of the compressor to a relatively small displacement
by interconnecting a compression chamber with a suction pressure
region after the compression chamber compresses until the
compression chamber reduces in volume to a predetermined value,
power loss of the compressor C caused due to re-compression for the
refrigerant gas, that is, due to useless compression work, is
suppressed.
[0046] (3) The first valve holes 61e partially constitute the
by-pass passages 48, 61e and 61f on an upstream side (a side of the
compression chamber 67). The first valve hole 61e is plurally
provided. Each of the first valve holes 61e interconnects the
compression chamber 67 with the communication chamber 48 at a
position that is different from each other. The different portions
of the front end surface 46a of the valve plate 46 simultaneously
opens and closes a plurality of the first valve holes 61e.
Therefore, the above described continuous communication between the
compression chamber 67 in the process of volume reduction and the
suction chamber 69 can be easily achieved without any complicated
structure.
[0047] Namely, for example, it is necessary to utilize a plurality
of spool valves to open and close a plurality of valve holes due to
interspersion of a plurality of the valve holes as disclosed in
Japanese Unexamined Patent Publication No. 2001-32787. However,
according to the valve plate 46 utilized in the present preferred
embodiment, simple structure, in which the valve plate 46 having a
size in accordance with the interspersion of a plurality of the
first valve holes 61e is utilized, preferably deals with
interspersion of a plurality of the first valve holes 61e.
[0048] (4) The valve plate 46 simultaneously opens and closes the
second valve 61f that partially constitutes the by-pass passages
48, 61e and 61f on the side of the suction chamber 69 relative to
the communication chamber 48. Therefore, the first and second valve
holes 61e and 61f are simultaneously, closed in a state where the
valve plate 46 is located at the close position, and sealing the
by-pass passages 48, 61e and 61f can be ensured further.
[0049] (5) The valve plate 46 is arranged along the fixed base
plate 61 of the fixed scroll member 41. Even though the compressor
C includes the variable displacement mechanism, the compressor C is
not lengthened in a direction of the axis L due to such arrangement
of the valve plate 46. In, other word, by utilizing the valve plate
46 (a plate-shaped body) as an open-close means for opening and
closing the by-pass passages 48, 61e and 61f, compact design to
arrange the open-close means along the fixed base plate 61 of the
fixed scroll member 41 is achieved.
[0050] Particularly, the compressor C is a hybrid compressor that
is selectively driven by one of the power from the engine E through
the power transmission mechanism 22 arranged at the housing 11 and
the power from the electric motor 21 installed in the housing 11.
Therefore, the compressor C tends to be large-sized by including
the power transmission mechanism 22 and the electric motor 21. When
a compact variable displacement mechanism is utilized in the
compressor C, increasing size of the compressor C is effectively
suppressed.
[0051] (6) The valve plate 46 has an incomplete annular shape that
is an annular shape of which a part is removed therefrom. The
discharge hole 61c is arranged at the center (the through hole) of
the valve plate 46 for discharging the compressed refrigerant gas
from the compression chamber 67 near the center of the fixed base
plate 61 with the discharge chamber 70. As mentioned above, since
the discharge hole 61 c is formed at the center of the valve plate
46 that is not utilized for opening and closing the first and
second valve holes 61e and 61f, the compression chamber 67 near the
center of the fixed base plate 61 can be interconnected with the
discharge chamber 70 at a minimum distance. Therefore, the
refrigerant gas can smoothly flow from the compression chamber 67
near the center of the fixed base plate 61 to the discharge chamber
70 so that the compressor C is prevented from deteriorating
efficiency of the compressor C due to pressure loss based on
conduit resistance between the compression chamber 67 and discharge
chamber 70.
[0052] (7) The rubber coat 46b is provided at the front end surface
46a of the valve plate 46 for sealing the by-pass passages 48, 61e
and 61f in a state where the valve plate 46 is located at the close
position. Therefore, sealing the by-pass passages 48, 61 e and 61f
in a state where the valve plate 46 is located at the close
position can be ensured further. Namely, the valve plate 46 is
utilized as the open-close means for opening and closing the
by-pass passages 48, 61e and 61f, and the structure, in which the
front end surface 46a of the valve plate 46 contacts the valve seat
surface 48a and is separated from the valve seat surface 48a, is
utilized. Therefore, it is possible to arrange the rubber coat 46b
for improving the seal of the by-pass passages 48, 61e and 61f in a
state where the valve plate 46 is located at the close position
without inhibiting the mobility of the valve plate 46.
[0053] Following alternative embodiments may be practiced according
to the present invention.
[0054] In the above preferred embodiment, only the single valve
plate 46 is provided. Therefore, the displacement of the compressor
C is switched only between the maximum displacement by locating the
valve plate 46 at the close position and the minimum displacement
by locating the valve plate 46 at the open position. The valve
plate 46 may be divided into a plurality of parts, and the
displacement of the compressor C may be switched among more than
three displacements.
[0055] Namely, for example, the valve plate 46 in the above
preferred embodiment is divided into first and second parts. The
first part of the valve plate 46 opens and closes a group of the
first valve holes 61e that interconnect the suction chamber 69 with
the compression chamber 67 in the process of volume reduction whose
volume ranges from the maximum volume to a certain value (larger
than the predetermined value). The second part of the valve plate
46 opens and closes another group of the first valve holes 61e that
interconnect the suction chamber 69 with the compression chamber 67
in the process of volume reduction whose volume ranges from the
certain value to the predetermined value. In this case, when the
first and second parts of the valve plate 46 are located at the
close position, the displacement of the compressor C becomes the
maximum. When the first and second parts of the valve plate 46 are
located at the open position, the displacement of the compressor C
becomes the minimum. When the first and second parts of the valve
plate 46 are respectively located at the open position and the
close position, the displacement of the compressor C becomes an
intermediate displacement between the maximum and the minimum.
[0056] In the above preferred embodiment, the valve plate 46 has an
annular shape of which a part is removed therefrom so as to avoid
the discharge valve 55 and the base of the retainer 56 as shown in
FIG. 2. However, when a short discharge valve 55 and a short
retainer 56 are utilized and the bases of the discharge valve 65
and the retainer 56 are located closer to the center of the fixed
scroll member 41 (the side of the discharge hole 61c), the valve
plate 46 may, be formed in a complete annular shape so as to
surround the discharge valve 55 and the retainer 56. In this case,
the same advantageous effect is obtained as mentioned in paragraph
(6) according to the above preferred embodiment.
[0057] In the above preferred embodiment, the by-pass passages 48,
61e and 61f are formed so as to continuously interconnect the
compression chamber 67 with the suction chamber 69 until the
compression chamber 67 in the process of volume reduction reduces
in volume to the predetermined value in a state where the valve
plate 46 is located at the open position. However, the by-pass
passages 48, 61e and 61f are not limited to the above preferred
embodiment and may be formed so as to interconnect the compression
chamber 67 with the suction pressure region after the compression
chamber 67 has compressed to reduce in volume to a predetermined
value. This manner reduces the number of the first valve holes 61e
and simplifies the structure of the by-pass passage.
[0058] In the above preferred embodiment, the valve plate 46 moves
between the open position and the close position by regulating the
pressure in the back pressure chamber 49 by the control valve 58.
The valve plate 46 may be formed to move between the open position
and the close position by directly actuating the valve plate 46 by
an electromagnetic actuator.
[0059] Therefore, the present examples and embodiments are to be
considered as illustrative and not restrictive, and the invention
is not to be limited to the details given herein but may be
modified within the scope of the appended claims.
* * * * *