U.S. patent application number 11/998032 was filed with the patent office on 2008-05-29 for compressor having a mechanism for separating and recovering lubrication oil.
Invention is credited to Yoshinori Inoue, Akinobu Kanai, Naoki Koeda, Hiroyuki Nakaima.
Application Number | 20080120991 11/998032 |
Document ID | / |
Family ID | 39135370 |
Filed Date | 2008-05-29 |
United States Patent
Application |
20080120991 |
Kind Code |
A1 |
Inoue; Yoshinori ; et
al. |
May 29, 2008 |
Compressor having a mechanism for separating and recovering
lubrication oil
Abstract
A compressor has a discharge passage, an oil separation
mechanism, an oil supply passage, and a valve mechanism. The oil
supply passage supplies the separated lubrication oil into an oil
recovery region. The valve mechanism is formed in the oil supply
passage and includes a valve chamber, a spool and an urging member.
The spool separates the valve chamber into a first pressure sensing
chamber and a second pressure sensing chamber. The amount of the
lubrication oil supplied to the oil recovery region is adjusted in
such a manner that as the pressure differential between the first
and the second pressure sensing chambers increases, the spool
slides in the valve chamber and the opening degree of the oil
supply passage increases to the maximum and then decreases, and
that when the compressor is stopped, the opening degree of the oil
supply passage is minimized by the urging force of the urging
member.
Inventors: |
Inoue; Yoshinori;
(Kariya-shi, JP) ; Nakaima; Hiroyuki; (Kariya-shi,
JP) ; Kanai; Akinobu; (Kariya-shi, JP) ;
Koeda; Naoki; (Kariya-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
3 WORLD FINANCIAL CENTER
NEW YORK
NY
10281-2101
US
|
Family ID: |
39135370 |
Appl. No.: |
11/998032 |
Filed: |
November 27, 2007 |
Current U.S.
Class: |
62/470 ;
92/12.2 |
Current CPC
Class: |
F04B 39/16 20130101;
F04B 27/109 20130101; F04B 49/03 20130101 |
Class at
Publication: |
62/470 ;
92/12.2 |
International
Class: |
F04B 27/10 20060101
F04B027/10; F25B 31/00 20060101 F25B031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 29, 2006 |
JP |
P2006-322384 |
Claims
1. A compressor comprising: an outlet for discharging refrigerant
gas out from the compressor; a discharge passage connected to the
outlet, wherein the refrigerant gas is discharged through the
discharge passage and the outlet; an oil separation mechanism for
separating lubrication oil from the refrigerant gas; an oil supply
passage supplying the separated lubrication oil into an oil
recovery region; a valve mechanism formed in the oil supply
passage, wherein the valve mechanism includes a valve chamber, a
spool and an urging member, wherein the spool separates the valve
chamber into a first pressure sensing chamber and a second pressure
sensing chamber; wherein the amount of the lubrication oil supplied
to the oil recovery region is adjusted in such a manner that as the
pressure differential between the first pressure sensing chamber
and the second pressure sensing chamber increases, the spool slides
in the valve chamber and the opening degree of the oil supply
passage increases to the maximum and then decreases, and that when
the compressor is stopped, the opening degree of the oil supply
passage is minimized by the urging force of the urging member.
2. The compressor according to claim 1, wherein the first pressure
sensing chamber is connected to a high pressure region and the
second pressure sensing chamber is connected to a low pressure
region.
3. The compressor according to claim 2, wherein the high pressure
region includes a discharge passage, and the low pressure region
includes a suction chamber.
4. The compressor according to claim 1, wherein the oil recovery
region includes a suction chamber.
5. The compressor according to claim 1, wherein the oil supply
passage includes an oil passage which communicates the valve
chamber to the oil recovery region, wherein an oil introduction
hole is formed in the spool facing the first pressure sensing
chamber so as to face a circumferential surface of the valve
chamber at a side surface thereof, wherein the oil introduction
hole overlaps an opening end of the oil passage formed in the
circumferential surface of the valve chamber when the spool slides,
so as to open the oil supply passage, wherein the opening degree of
the oil supply passage is adjusted in accordance with an area where
the oil introduction hole and the opening end of the oil passage
overlap.
6. The compressor according to claim 1, wherein a groove is formed
on the valve chamber to be positioned so that the first pressure
sensing chamber and the second pressure sensing chamber communicate
through the groove when the spool slides so as to open the oil
supply passage.
7. The compressor according to claim 1, wherein the first pressure
sensing chamber is connected to an upstream of the oil separation
mechanism and the second pressure sensing chamber is connected to a
downstream of the oil separation mechanism, wherein the spool is
moved by the pressure differential between the upstream and the
downstream of the oil separation mechanism.
8. The compressor according to claim 7, wherein the discharge
passage has a branching point connecting to the second pressure
sensing chamber, and a check valve is formed between the branching
point and the oil separation mechanism in the discharge
passage.
9. The compressor according to claim 1, wherein the oil separation
chamber is integrally formed with the valve chamber.
10. The compressor according to claim 1, wherein the urging member
is a spring.
11. The compressor according to claim 1, wherein the urging member
is a pair of magnets to be formed to generate a repelling force
with each other.
12. A compressor comprising an outlet for discharging refrigerant
gas out from the compressor; a discharge passage connected to the
outlet, wherein the refrigerant gas is discharged through the
discharge passage and the outlet; an oil separation mechanism for
separating lubrication oil from the refrigerant gas; an oil supply
passage supplying the separated lubrication oil into an oil
recovery region and including an oil passage; a valve mechanism
formed in the oil supply passage, wherein the valve mechanism
includes a valve chamber, a spool and an urging member, wherein the
spool separates the valve chamber into a first pressure sensing
chamber and a second pressure sensing chamber, the spool being
moved in the valve chamber in accordance with the pressure
differential between the first pressure sensing chamber and the
second pressure sensing chamber, wherein the spool includes an oil
introduction hole facing the first pressure sensing chamber and a
circumferential surface of the valve chamber; wherein the oil
passage communicates the valve chamber to the oil recovery region
and has an opening end formed on the circumferential surface of the
valve chamber, an opening degree of the oil supply passage being
determined in accordance with a communicating area where the oil
introduction hole facing the circumferential surface of the valve
chamber and the opening end of the oil passage overlap; wherein as
the pressure differential increases, the spool is moved in the
valve chamber against the urging member such that the oil
introduction hole facing the circumferential surface of the valve
chamber and the opening end of the oil passage begins to overlap,
the communicating area becomes maximum and the oil introduction
hole facing the circumferential surface of the valve chamber begins
to pass through the opening end of the oil passage, so that the
opening degree of the oil supply passage becomes maximum from
minimum and then becomes smaller than the maximum, and wherein the
opening degree of the oil supply passage is minimized by the urging
member when the compressor is stopped.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a compressor used in an air
conditioner for a vehicle, and more specifically to a compressor
having a mechanism for separating lubrication oil from compressed
refrigerant gas and recovering the lubrication oil.
[0002] In a compressor for use in an air conditioner for a vehicle,
lubrication oil is mixed in the form of mist in refrigerant gas and
lubricates movable sliding parts. When the lubrication oil mixed in
the refrigerant gas flows out of the compressor together with the
refrigerant gas and circulates in the external refrigerant circuit,
the oil adheres to an inner wall of an evaporator and the like, and
deteriorates the heat exchange efficiency.
[0003] Conventionally, an oil separator is formed outside a
compressor and is located in the high-pressure piping connecting
the compressor to a condenser. The separated lubrication oil is
recovered into the compressor through an oil recovery passage. When
the oil separator outside of the compressor is utilized, however,
the construction of the whole refrigerant circuit becomes congested
with equipments and additional piping. Furthermore, the oil
recovery passage is elongated and has a small diameter so that
problems such as clogging may occur. Therefore, an oil separator
formed inside a compressor has been offered recently.
[0004] In the above-described compressor, the lubrication oil is
separated in the oil separation mechanism and is supplied from the
oil separation mechanism to a low pressure region through an oil
supply passage. When the compressor is stopped, all the stored oil
flows out to the low pressure region through the oil supply
passage. Therefore, when the compressor restarts,
highly-pressurized refrigerant gas may flow reversely through the
oil supply passage, and the lubrication oil stored in the low
pressure region may be compressed in liquid state. In order to
avoid such problems, Unexamined Japanese Patent Publication No.
05-240158 discloses a compressor which includes an oil separation
chamber, a primary oil storage chamber, a main oil storage chamber,
an oil recovery hole, and a valve means. The oil separation chamber
is formed in a high pressure region inside the compressor. The
primary oil storage chamber for recovering lubrication oil is
located below the oil separation chamber. The main oil storage
chamber is connected to the primary oil storage chamber via a hole.
The hole extends upward from a bottom portion of the primary oil
storage chamber to the main oil storage chamber. The lubrication
oil in the primary oil storage chamber flows upward through the
hole and drops downward in the main storage chamber. The oil
recovery hole is opened in a valve seat surface formed at the
bottom of the main oil storage chamber and connects the main oil
storage chamber to the low pressure region inside the compressor.
The valve means adjusts the flow rate of the lubrication oil to be
recovered in accordance with the pressure differential between the
high pressure region and the low pressure region. In accordance
with the increase of the pressure differential between the high
pressure region and the low pressure region, the valve means
adjusts the flow rate of the lubrication oil to be gradually
decreased. The valve means ensures an optimal amount of the
lubrication oil based on the balance between the amount of the
separated lubrication oil and the required amount of the
lubrication oil to be recovered. On the other hand, after the
compressor is stopped, the move of the separated lubrication oil
between the primary oil storage chamber and the main oil storage
chamber is stopped at the time when the pressure differential is
balanced to the force due to the weight of the lubrication oil
which is in the hole. When the pressure in the refrigerant circuit
is balanced, the optimal amount of the lubrication oil is stored in
the primary oil storage chamber. However, when the pressure
differential is relatively small due to the small flow rate of the
refrigerant gas, the opening degree of the oil recovery hole is
fully opened and the amount of the separated lubrication oil is
small in comparison to the amount of the recovered lubrication oil.
Accordingly, all the stored oil flows out to the low pressure
region. As described above, the refrigerant gas may flow reversely
and the lubrication oil may be compressed in liquid state.
Furthermore, the structure of the valve means is complicated,
thereby needs many assembling processes and accuracy in
manufacturing.
SUMMARY OF THE INVENTION
[0005] In accordance with the present invention, a compressor has
an outlet, a discharge passage, an oil separation mechanism, an oil
supply passage, and a valve mechanism. The outlet discharges
refrigerant gas out from the compressor. The discharge passage is
connected to the outlet, and the refrigerant gas is discharged
through the discharge passage and the outlet from the compressor.
The oil separation mechanism separates lubrication oil from the
refrigerant gas. The oil supply passage supplies the separated
lubrication oil into an oil recovery region. The valve mechanism is
formed in the oil supply passage and includes a valve chamber, a
spool and an urging member. The spool separates the valve chamber
into a first pressure sensing chamber and a second pressure sensing
chamber. The amount of the lubrication oil supplied to the oil
recovery region is adjusted in such a manner that as the pressure
differential between the first pressure sensing chamber and the
second pressure sensing chamber increases, the spool slides in the
valve chamber and the opening degree of the oil supply passage
increases to the maximum and then decreases, and that when the
compressor is stopped, the opening degree of the oil supply passage
is minimized by the urging force of the urging member.
[0006] 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
[0007] 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:
[0008] FIG. 1 is a longitudinal cross-sectional view of a variable
displacement swash plate compressor according to a first preferred
embodiment of the present invention;
[0009] FIG. 2 is an enlarged schematic view of a valve mechanism in
a state where the valve mechanism is fully opened;
[0010] FIG. 3 is an enlarged schematic view of the valve mechanism
in a state where the compressor is at a maximum displacement
operational mode according to the first preferred embodiment of the
present invention;
[0011] FIG. 4 is an enlarged schematic view of the valve mechanism
in a state where the compressor is stopped according to the first
preferred embodiment of the present invention;
[0012] FIG. 5 is a graph showing a relation between the pressure
differential acting on a spool of the valve mechanism and the
opening degree of an oil supply passage according to the present
invention;
[0013] FIG. 6 is a longitudinal cross-sectional view of a variable
displacement swash plate compressor according to a second preferred
embodiment of the present invention;
[0014] FIG. 7 is an enlarged schematic view of a valve mechanism in
a state where the valve mechanism is fully opened according to the
second preferred embodiment of the present invention;
[0015] FIG. 8 is an enlarged schematic view of the valve mechanism
in a state where the compressor is at a maximum displacement
operational mode according to the second preferred embodiment of
the present invention;
[0016] FIG. 9 is an enlarged schematic view of the valve mechanism
in a state where the compressor is stopped according to the second
preferred embodiment of the present invention;
[0017] FIG. 10 is a longitudinal cross-sectional view of a variable
displacement swash plate compressor according to a third preferred
embodiment of the present invention;
[0018] FIG. 11 is a longitudinal cross-sectional view of a variable
displacement swash plate compressor according to a fourth preferred
embodiment of the present invention; and
[0019] FIG. 12 is a longitudinal cross-sectional view of a variable
displacement swash plate compressor according to an alternative
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] A first preferred embodiment of a variable displacement
swash plate compressor 10 (hereinafter referred to as a
"compressor") according to the present invention will now be
described with reference to FIGS. 1 through 5.
[0021] Referring to FIG. 1, the compressor 10 includes a cylinder
block 11, a front housing 12 and a rear housing 14. The left-hand
side of the compressor 10 corresponds to the front side and the
right-hand side of the compressor 10 corresponds to the rear side
as viewed in FIG. 1. The front housing 12 is connected to the front
end of the cylinder block 11. The rear housing 14 is connected to
the rear end of the cylinder block 11 through a valve port plate
assembly 13. The cylinder block 11, the front housing 12 and the
rear housing 14 cooperate to form a housing of the compressor 10. A
crank chamber 15 is defined by the cylinder block 11 and the front
housing 12. A drive shaft 16 is rotatably disposed in the crank
chamber 15. The front end portion of the drive shaft 16 protrudes
from the crank chamber 15 and is coupled to a vehicle engine (not
shown) to receive driving force so that the drive shaft 16 is
rotated.
[0022] A lug plate 17 is disposed in the crank chamber 15 and fixed
to the drive shaft 16 for rotation therewith. A swash plate 18 is
disposed in the crank chamber 15. The swash plate 18 is supported
by the drive shaft 16 so as to be slidable in the axial direction
of the drive shaft 16 and also inclinable relative to the axis of
the drive shaft 16. The swash plate 18 is connected to the lug
plate 17 via a hinge mechanism 19. The hinge mechanism 19 is
provided between the lug plate 17 and the swash plate 18. Through
the hinge mechanism 19 the swash plate 18 is synchronously
rotatable with the lug plate 17 and the drive shaft 16 and
inclinable relative to the axial direction of the drive shaft 16
with sliding on the drive shaft 16. The inclination angle of the
swash plate 18 is adjusted by a control valve 20.
[0023] A plurality of cylinder bores 21 (two of the cylinder bores
are shown in FIG. 1) are formed in the cylinder block 11 for
accommodating a reciprocable single-headed piston 22 respectively.
In each cylinder bore 21, a compression chamber 23 is defined by
the piston 22 and the valve port plate assembly 13. Each piston 22
is engaged with the outer periphery of the swash plate 18 through a
pair of shoes 24. The rotation of the swash plate 18 in accordance
with the rotation of the drive shaft 16 is converted to the
reciprocation of the pistons 22 through the pair of shoes 24 so
that each piston 22 reciprocates in the respective cylinder bore
21.
[0024] A suction chamber 25 is defined in the rear housing 14 at
the center thereof, and a discharge chamber 26 is defined around
the suction chamber 25 in the rear housing 14. Suction ports 27 and
suction valves 28 are formed in the valve port plate assembly 13.
Discharge ports 29 and discharge valves 30 are formed in the valve
port plate assembly 13. Refrigerant gas in the suction chamber 25
is introduced into the compression chamber 23 through the
respective suction port 27 by pushing away the respective suction
valve 28 as the piston 22 moves from its top dead center position
to its bottom dead center position. The refrigerant gas is
compressed in the compression chamber 23 to a predetermined
pressure level, and is discharged into the discharge chamber 26
through the discharge port 29 while pushing away the discharge
valve 30 as the piston 28 moves from its bottom dead center
position to its top dead center position.
[0025] The rear housing 14 has an inlet 31 and an outlet 32. The
inlet 31 is connected to an external refrigerant circuit (not
shown) and the refrigerant gas is introduced into the suction
chamber 25 through the inlet 31. The outlet 32 is connected to the
external refrigerant circuit. A discharge passage 33 is formed to
connect the outlet 32 and the discharge chamber 26. The refrigerant
gas in the discharge chamber 26 is discharged out from the
compressor 10 through the discharge passage 33 and the outlet 32.
An oil separation mechanism is formed in the discharge passage 33.
The oil separation mechanism includes an oil separation chamber 34
and an oil separation cylinder 35. The oil separation chamber 34 is
formed with a cylindrical shape with a bottom surface at the rear
end thereof. The oil separation cylinder 35 is received in the oil
separation chamber 34. A valve mechanism is integrally formed with
the oil separation mechanism. As shown in FIG. 1, the valve
mechanism is formed adjacent to the oil separation mechanism so
that the front end of the oil separation mechanism is shared by the
rear end of the valve mechanism. The valve mechanism includes a
valve chamber 36, a spool 38, and a spring 39 as an urging member.
The valve chamber 36 is formed in the rear housing 14 and has a
cylindrical shape with a bottom surface. The diameter of the valve
chamber 36 is greater than that of the oil separation chamber 34.
The spool 38 separates the valve chamber 36 into a first pressure
sensing chamber S1 and a second pressure sensing chamber S2. The
first pressure sensing chamber S1 is in communication with the
discharge chamber 26 and the discharge passage 33 as a high
pressure region through the oil separation chamber 34. The second
pressure sensing chamber S2 is in communication with the suction
chamber 25 as a low pressure region through a pressure introduction
passage 37. The spring 39 is disposed in the second pressure
sensing chamber S2 and urges the spool 38 in the direction toward
the rear end of the valve mechanism, or toward the oil separation
mechanism. In a side surface of the spool 38 which faces the first
pressure sensing chamber S1, an oil introduction hole 40 is formed
so as to face-a circumferential surface of the valve chamber 36. An
oil passage 41 supplies the lubrication oil to the suction chamber
25, and is formed in such a manner that one end of the oil passage
41 opens to the suction chamber 25 and the other end of the oil
passage 41 opens to the circumferential surface of the valve
chamber 36. The opening end of the oil passage 41 opened to the
valve chamber 36 is formed at a position where the oil introduction
hole 40 overlaps the opening end of the oil passage 41 when the
spool 38 slides. In the first preferred embodiment, an oil supply
passage includes the oil separation chamber 34, the valve chamber
36, the oil introduction hole 40, and the oil passage 41. The valve
mechanism is formed in the oil supply passage to adjust the opening
degree of the oil supply passage.
[0026] The following will describe the operation of the compressor
10 of the first embodiment. As the drive shaft 16 is rotated, the
swash plate 18 is rotated therewith and the piston 22 engaged with
the swash plate 18 reciprocates in the cylinder bore 21,
accordingly. As the piston 22 reciprocates, the refrigerant gas is
introduced into the compression chamber 23 from the suction chamber
25, and is compressed in the compression chamber 23, and then
discharged to the discharge chamber 26. The highly-pressurized
refrigerant gas is introduced into the oil separation chamber 34
from the discharge chamber 26 through the discharge passage 33. The
refrigerant gas introduced into the oil separation chamber 34 flows
through the opening of the oil separation cylinder 35 to the inside
of the oil separation cylinder 35 while swirling along the inner
cylindrical wall of the oil separation chamber 34. The refrigerant
gas is sent to the external refrigerant circuit (not shown) through
the outlet 32. In the meantime, the oil mixed in the refrigerant
gas is separated from the refrigerant gas by the centrifugal force
generated by the swirling flow.
[0027] When the compressor 10 is not operated, the opening degree
of the oil supply passage is minimum. When the compressor 10
starts, pressure differential is generated between the pressure, in
the first pressure sensing chamber S1 which acts on the rear side
of the spool 38 and the pressure in the second pressure sensing
chamber S2 which acts on the front side of the spool 38. The
pressure in the first pressure sensing chamber S1 is based on the
refrigerant gas introduced from the discharge chamber 26 through
the discharge passage 33. The pressure in the second pressure
sensing chamber S2 is based on the refrigerant gas introduced from
the suction chamber 25 through the pressure introduction passage
37. Accordingly, the pressure differential between the first
pressure sensing chamber S1 and the second pressure sensing chamber
S2, that is, the pressure differential which acts on the spool 38,
overcomes the urging force of the spring 39, and the spool 38
slides frontward, or in the direction away from the oil separation
mechanism to some extent in such a manner that the volume of the
second pressure sensing chamber S2 is decreased and the oil
introduction hole 40 begins to overlap with the opening end of the
oil passage 41. As shown in FIG. 2, when the oil passage 41 is
fully opened, the opening degree of the oil supply passage
increases to the maximum. The oil separation chamber 34 is in
communication with the oil passage 41 through the oil introduction
hole 40. The lubrication oil separated in the oil separation
chamber 34 is temporarily stored in the oil separation chamber 34,
and Introduced into the oil passage 41 through the oil introduction
hole 40. Then the lubrication oil is recovered to the suction
chamber 25.
[0028] As the pressure differential which acts on the spool 38
increases, the amount of the lubrication oil supplied to the
suction chamber 25 increases until the opening degree of the oil
supply passage increases to the maximum. Then, the spool 38 slides
further, and the oil introduction hole 40 begins to pass through
the opening end of the oil passage 41. When the spool 38 slides and
moves to a position to partially close the opening of the oil
passage 41, as shown in FIG. 3, the opening degree of the oil
supply passage becomes decreasing. As a result, small amount of the
lubrication oil is recovered to such an extent that the lubrication
oil in the oil separation chamber 34 does not flow out completely.
Thereby, the circulation of lubrication oil in the compressor 10 is
maintained.
[0029] When the operation of the compressor 10 is stopped, the
pressure in the first pressure sensing chamber S1 decreases to
substantially the same level as the pressure in the second pressure
sensing chamber S2. The urging force of the spring 39 overcomes the
pressure differential which acts on the spool 38 so that the spool
38 is pushed rearward, or in the direction toward the oil
separation mechanism to make contact with the rear end surface of
the first pressure sensing chamber S1. The opening end of the oil
passage 41 is closed by the spool 38, and the communication between
the valve chamber 36 and the oil passage 41 is shut. In other
words, the opening degree of the oil supply passage is minimized by
the urging force of the spring 39. Thus, when the compressor 10 is
stopped, the circulation of the lubrication oil inside the
compressor 10 is stopped, and accordingly the recovery of the
lubrication oil to the suction chamber 25 is stopped.
[0030] According to the first preferred embodiment of the present
invention, the following advantageous effects are obtained.
(1) The compressor 10 has the valve mechanism which has the valve
chamber 36, the spool 38, and the spring 39. The valve chamber 36
is formed with the cylindrical shape with the bottom surface in the
rear housing 14. The spool 38 separates the valve chamber 36 into
the first pressure sensing chamber S1 and the second pressure
sensing chamber S2. The first pressure sensing chamber S1 is in
communication with the discharge chamber 26 and the discharge
passage 33. The second pressure sensing chamber S2 is in
communication with the suction chamber 25. The spring 39 is
disposed in the second pressure sensing chamber S2 and urges the
spool 38 in the direction rearward, or toward the oil separation
mechanism. The oil introduction hole 40 is formed in the side
surface of the spool 38 which faces the first pressure sensing
chamber S1 so as to face the circumferential surface of the valve
chamber 36. The oil passage 41 has a opening end in the
circumferential surface of the valve chamber 36 at a position where
the opening end of the oil passage 41 overlaps the oil introduction
hole 40 when the spool 38 slides. Accordingly, when the compressor
10 starts, the pressure differential which acts on the spool 88
overcomes the urging force of the spring 39 to move the spool 38
frontward, or in the direction so as to decrease the volume of the
second pressure sensing chamber S2. The oil separation chamber 34
and the oil passage 41 communicate through the oil introduction
hole 40, and the lubrication oil separated in the oil separation
chamber 34 is introduced into the oil passage 41 through the oil
introduction hole 40, and then is recovered to the suction chamber
25. As the pressure differential acting on the spool 38 increases
further, the spool 38 slides to a position where the oil
introduction hole 40 partially faces the opening end of the oil
passage 41 and the spool 38 partially closes the opening end of the
oil passage 41, that is, the front end of the oil introduction hole
40 passes through the front end of the oil passage 41, so that the
opening degree of the oil supply passage is decreased accordingly.
Thus, the opening degree of the oil supply passage becomes maximum
from minimum and then becomes smaller than the maximum in
accordance with the pressure differential acting on the spool 38.
The opening degree of the oil supply passage is set at an optimal
value in accordance with the pressure differential acting on the
spool 38 as shown in the graph in FIG. 5, and that can ensure the
optimal amount of the recovered lubrication oil, without excess nor
deficiency, at any operational mode.
[0031] Further, the oil introduction hole 40 is formed in the side
surface of the spool 38, and the relation with the opening end of
the oil passage 41 is changed in accordance with the sliding
movement of the spool 38. The communicating area where the oil
introduction hole 40 and the opening end of the oil passage 41
overlaps increases in accordance with the increase of the pressure
differential acting on the spool 38, and after the communicating
area becomes the maximum, the communicating area decreases.
Accordingly, the opening degree of the oil supply passage is
adjusted with the simple structure manufactured by simple
processes.
(2) The oil separation chamber 34 and the valve chamber 36 are
adjacent to each other, and the front end of the oil separation
chamber 34 is shared by the rear end of the valve chamber 36. As
the pressure differential acting on the spool 38 increases, the
spool 38 slides frontward, or in the direction away from the oil
separation mechanism so as to decrease the volume of the second
pressure sensing chamber S2. Accordingly, the first pressure
sensing chamber S1 which is on the rear side of the spool 38 can be
used as an additional oil separation space. Therefore the whole
space used for storing lubrication oil is increased. In general,
when pressure differential between a high pressure region and a low
pressure region in the compressor 10 is large, the flow rate in the
compressor 10 is large. Thus, the volume of the whole space can be
enlarged in accordance with the amount of the separated lubrication
oil, which increases in accordance with the increase of the flow
rate of the refrigerant gas. Further, the front end of the oil
separation chamber 34 is applicable as a valve seat of the spool
38, so the compressor 10 can be manufactured by simple
structure.
[0032] A second preferred embodiment of the present invention will
now be described with reference to FIG. 6. The compressor of the
second embodiment differs from that of the first embodiment in that
the structure of the valve mechanism is modified, and the rest of
the structure of the compressor of the second embodiment is
substantially the same as the first embodiment. For the sake of
convenience of explanation, therefore, like or same parts or
elements will be referred to by the same reference numerals as
those which have been used in the first embodiment, and the
description thereof. Will be omitted.
[0033] As shown in FIG. 6, a valve mechanism of the second
embodiment has the valve chamber 36, the spool 38, and the spring
39 as the urging member. The valve chamber 36 is formed in the rear
housing 14 and has the cylindrical shape with the bottom surface.
The spool 38 separates the valve chamber 36 into the first pressure
sensing chamber S1 and the second pressure sensing chamber S2. The
first pressure sensing chamber S1 is in communication with the
discharge chamber 26 and the discharge passage 33 as a high
pressure region through the oil separation chamber 34. The second
pressure sensing chamber S2 is in communication with the suction
chamber 25 as a low pressure region through the oil passage 41. The
spring 39 is disposed in the second pressure sensing chamber S2 of
the valve chamber 36 and urges the spool 38 rearward, or in the
direction toward the oil separation mechanism. A groove 42 is
formed in the circumferential surface of the valve chamber 36. The
groove 42 is formed at a position where the groove 42 is partially
covered by the spool 38 and formed so that the communication
between the groove 42 and the first pressure sensing chamber S1 is
shut, when the compressor 10 is stopped. In addition, the position
of the groove 42 is set so that the first pressure sensing chamber
S1 and the second pressure sensing chamber S2 communicate through
the groove 42 to open the oil supply passage, when the spool 38
slides frontward from the rear end of the valve mechanism. In the
second embodiment, specifically, the groove 42 is formed along the
sliding direction of the spool 38, as shown in FIG. 7 through FIG.
9. The oil supply passage of the second embodiment includes the oil
separation chamber 34, the valve chamber 36, the oil passage 41 and
the groove 42. The valve mechanism is formed in the oil supply
passage to adjust the opening degree of the oil supply passage.
[0034] When the compressor 10 starts, the pressure differential
acting on the spool 38 overcomes the urging force of the spring 39,
and the spool 38 slides to some extent in the direction away from
the oil separation mechanism, as shown in FIG. 7. Accordingly, the
first pressure sensing chamber S1 and the second pressure sensing
chamber S2 communicate through the groove 42 as shown in FIG. 7,
and the separated lubrication oil in the oil separation chamber 34
is introduced into the oil passage 41 through the groove 42, and
then is recovered to the suction chamber 25.
[0035] As the pressure in the first pressure sensing chamber S1
increases, the pressure differential acting on the spool 38
increases, and the amount of the lubrication oil supplied to the
suction chamber 25 increases until the opening degree of the oil
supply passage is maximum. Then, the spool 38 slides to a position
where the area of the groove 42 communicating with the first
pressure sensing chamber S1 becomes larger than the area of the
groove 42 communicating with the second pressure sensing chamber
S2, as shown in FIG. 8. Accordingly, the opening degree of the oil
supply passage is decreased. As a result, small amount of the
lubrication oil is recovered to such an extent that the stored
lubrication oil does not flow out completely, thereby the
circulation of the lubrication oil is maintained.
[0036] When the compressor 10 is stopped, the pressure in the first
pressure sensing chamber S1 decreases to substantially the same
level as that of the second pressure sensing chamber S2. The urging
force of the spring 39 overcomes the pressure differential acting
on the spool 38 so that the spool 38 is pushed toward the end
surface of the first pressure sensing chamber S1 so as to make
contact with the end surface of the first pressure sensing chamber
S1, and then the communication between the first pressure sensing
chamber S1 and the groove 42 is shut. Thus, when the compressor 10
is stopped, the circulation of the lubrication oil inside the
compressor 10 is stopped, and accordingly the recovery of the
lubrication oil to the suction chamber 25 is stopped.
[0037] According to the second embodiment of the present invention,
the similar effect as (2) of the first embodiment is obtained, and
further, the following advantageous effect (3) instead of (1) of
the first embodiment is obtained.
(3) The compressor 10 includes the valve mechanism which has the
valve chamber 36, the spool 38, and the spring 39. The valve
chamber 36 is formed with the cylindrical shape with the bottom
surface in the rear housing 14. The spool 38 separates the valve
chamber 36 into the first pressure sensing chamber 81 and the
second pressure sensing chamber S2. The first pressure sensing
chamber S1 is in communication with the discharge chamber 26 and
the discharge passage 33. The second pressure sensing chamber 82 is
in communication with the suction chamber 25. The spring 39 is
disposed in the second pressure sensing chamber S2 and urges the
spool 38 in the direction toward the oil separation mechanism so as
to increase the volume of the second pressure sensing chamber S2.
The groove 42 is formed in the circumferential surface of the valve
chamber 36 at a position where the communication between the groove
42 and the first pressure sensing chamber S1 is shut by the spool
38 when the compressor 10 is stopped. In addition, the position of
the groove 42 is set so that the first pressure sensing chamber S1
and the second pressure sensing chamber S2 communicate through the
groove 42 to open the oil supply passage, when the spool 38 slides
frontward from the rear end of the valve mechanism. Accordingly,
when the compressor 10 starts, the pressure differential acting on
the spool 38 overcomes the urging force of the spring 39 to move
the spool 38 in the direction away from the oil separation
mechanism. Thus, the first pressure sensing chamber S1 and the
second pressure sensing chamber S2 communicate through the groove
42, and the lubrication oil separated in the oil separation chamber
34 is introduced into the oil passage 41 through the groove 42, and
is recovered to the suction chamber 25. As the pressure
differential acting on the spool 38 increases further, the spool 38
slides to a position where the area of the groove 42 communicating
with the first pressure sensing chamber S1 becomes larger than the
area of the groove 42 communicating with the second pressure
sensing chamber S2, and accordingly the opening degree of the oil
supply passage is decreased. As a result, an optimal amount of the
lubrication oil can be ensured, without excess nor deficiency at
any operational mode. Further, the opening degree of the oil supply
passage is adjusted with the simple structure manufactured by
simple processes.
[0038] A third preferred embodiment of the present invention will
now be described with reference to FIG. 10. The compressor of the
third embodiment differs from that of the first embodiment in that
the method for adjusting the valve mechanism is modified, and the
rest of the compressor of the third embodiment is substantially the
same as the first embodiment. For the sake of convenience of
explanation, therefore, like or same parts or elements will be
referred to by the same reference numerals as those which have been
used in the first embodiment, and the description thereof will be
omitted.
[0039] As shown in FIG. 10, a valve mechanism of the third
embodiment has a second pressure sensing chamber S2 which is in
communication with the downstream of the oil separation mechanism
in the discharge passage 33, instead that the second pressure
sensing chamber S2 of the first embodiment is in communication with
the suction chamber 25. Thereby, during the operation of the
compressor 10, the pressure in the second pressure sensing chamber
S2 is substantially equal to the pressure in the downstream of the
oil separation mechanism in the discharge passage 33.
[0040] A check valve 43 is formed in the discharge passage 33. In
detail, the check valve 43 is formed between the oil separation
mechanism and a branching point connecting to the second pressure
sensing chamber S2. Thereby, when the compressor is stopped, only
the pressure in the second pressure sensing chamber S2 is
substantially equal to the pressure in the external refrigerant
circuit. In the third embodiment, the oil supply passage includes
the oil separation chamber 34, the valve chamber 36, the oil
introduction hole 40, and the oil passage 41.
[0041] When the compressor 10 starts, pressure differential is
generated between the upstream and the downstream of the oil
separation mechanism in the discharge passage 33, and thereby
pressure differential is generated between the first pressure
sensing chamber S1 and the second pressure sensing chamber S2. The
pressure differential acting on the spool 38 overcomes the urging
force of the spring 39 to move the spool 38 frontward, or in the
direction away from the oil separation mechanism to some extent.
Thereby the oil separation chamber 34 and the oil passage 41
communicate through the oil introduction hole 40, and the
lubrication oil separated in the oil separation chamber 34 is
introduced into the oil passage 41 through the oil introduction
hole 40, and then is recovered to the suction chamber 25.
[0042] As the flow rate in the compressor 10 increases, the
pressure differential between the upstream and the downstream of
the oil separation mechanism increases, and as a result the
pressure differential acting on the spool 38 increases. In
accordance with the increase in the pressure differential acting on
the spool 38, the spool 38 slides to a position where the opening
degree of the oil supply passage is maximum, and then to a position
where the oil introduction hole 40 is moved past the opening end of
the oil passage 41 and the spool 38 partially covers the oil
passage 41 so that the opening degree of the oil supply passage is
decreased.
[0043] When the operation of the compressor 10 is stopped, the
pressure in the discharge passage 33 decreases gradually, and
approaches the pressure in the external refrigerant circuit.
Thereby, when the compressor 10 is stopped, the pressure in the
second pressure sensing chamber S2 is substantially equal to the
pressure in the external refrigerant circuit. On the other hand,
the check valve 43 is closed, and the pressure in the first
pressure sensing chamber S1 is substantially equal to the pressure
in the discharge chamber 26. Thereby the pressure in the second
pressure sensing chamber S2 becomes larger than the pressure in the
first pressure sensing chamber S1, and the spool 38 slides to the
end surface of the first pressure sensing chamber S1 by the
pressure differential and the urging force of the spring 39 so as
to shut the communication between the valve chamber 36 and the oil
passage 41. Thus, when the compressor 10 is stopped, the
circulation of the lubrication oil in the compressor 10 and the
recovery to the suction chamber 25 is accordingly stopped.
[0044] According to the third embodiment of the present invention,
the similar effect as (2) of the first embodiment is obtained, and
further, the following advantageous effects (4) through (6) instead
of (1) of the first embodiment are obtained.
(4) The compressor 10 includes the valve mechanism which has the
valve chamber 36, the spool 38, and the spring 39. The valve
chamber 36 is formed with the cylindrical shape with the bottom
surface in the rear housing 14. The spool 38 separates the valve
chamber 36 into the first pressure sensing chamber S1 and the
second pressure sensing chamber S2. The first pressure sensing
chamber S1 is in communication with the discharge chamber 26 and
the discharge passage 33. The second pressure sensing chamber S2 is
in communication with the downstream of the oil separation
mechanism. The spring 39 is disposed in the second pressure sensing
chamber S2 and urges the spool 38 in the direction toward the oil
separation mechanism so as to increase the volume of the second
pressure sensing chamber S2. When the compressor 10 starts, the
pressure differential is generated between the upstream and the
downstream of the oil separation mechanism in the discharge passage
33, and thereby the pressure differential acts on the spool 38. Due
to the pressure differential, the spool 38 slides in the direction
away from the oil separation mechanism to some extent. Thereby the
oil separation chamber 34 and the oil passage 41 communicate
through the oil introduction hole 40. Thus, the lubrication oil
separated in the oil separation chamber 34 is introduced into the
oil passage 41 through the oil introduction hole 40, and is
recovered to the suction chamber 25. As the flow rate of the
refrigerant gas in the compressor 10 increases, the pressure
differential between the upstream and the downstream of the oil
separation mechanism increases accordingly, and as a result, the
pressure differential acting on the spool 38 increases. Due to the
increase in the pressure differential after the opening degree of
the oil supply passage is maximum, the spool 38 slides to a
position where the oil introduction hole 40 is moved past the
opening of the oil passage 41 and the spool 38 partially covers the
oil passage 41 to decrease the opening degree of the oil supply
passage. Thus, an optimal amount of the lubrication oil can be
ensured, without excess nor deficiency at any operational mode. (5)
The pressure differential acting on the spool 38 is substantially
equal to the pressure differential between the upstream and the
downstream of the oil separation mechanism. The pressure
differential varies in accordance with the flow rate of the
refrigerant gas in the compressor 10. Thereby the opening degree of
the oil supply passage can be adjusted in accordance with the
change in the flow rate of the refrigerant gas. (6) The check valve
43 is formed between the branching point to the second pressure
sensing chamber S2 and the oil separation mechanism in the
discharge passage 33. Accordingly, when the compressor 10 is
stopped, the spool 38 is urged toward the rear end surface of the
valve chamber 36 by the pressure in the external refrigerant
circuit in addition to the urging force. The oil supply passage can
be reliably shut.
[0045] A fourth preferred embodiment of the present invention will
now be described with reference to FIG. 11. The compressor of the
fourth embodiment differs from that of the first embodiment in that
the structure of the valve mechanism is modified, and the rest of
the structure of the compressor of the fourth embodiment is
substantially the same as the first embodiment. For the sake of
convenience of explanation, therefore, like or same parts or
elements will be referred to by the same reference numerals as
those which have been used in the first embodiment, and the
description thereof will be omitted.
[0046] As shown in FIG. 11, a valve mechanism of the fourth
embodiment has a pair of magnets 44 as an urging member. The pair
of magnets 44 are disposed in the valve chamber 36 to generate a
repelling force with each other. The magnets 44 urge the spool 38
rearward, or in the direction toward the oil separation mechanism.
The oil supply passage of the fourth embodiment includes the oil
separation chamber 34, the valve chamber 36, the oil introduction
hole 40, and the oil passage 41.
[0047] When the compressor 10 starts, the pressure differential
acting on the spool 38 overcomes the urging force generated by the
magnets 44, and the spool 38 slides in the direction away from the
oil separation mechanism to some extent. Accordingly, the oil
separation chamber 34 and the oil passage 41 communicate through
the oil introduction hole 40. The lubrication oil separated in the
oil separation chamber 34 is introduced into the oil passage 41,
and is recovered to the suction chamber 25.
[0048] As the pressure differential between the upstream and the
downstream of the oil separation mechanism increases, the pressure
differential acting on the spool 38 increases. Accordingly, after
the opening degree of the oil supply passage is maximum, the spool
38 slides to a position where the oil introduction hole 40 is moved
past the opening end of the oil passage 41 and the spool 38
partially covers the oil passage 41 to decrease the opening degree
of the oil supply passage.
[0049] When the compressor 10 is stopped, the pressure in the first
pressure sensing chamber S1 decreases to substantially the same
level as the pressure in the second pressure sensing chamber S2,
and the urging force generated by the magnets 44 overcomes the
pressure differential acting on the spool 38. The spool 38 is moved
in the direction toward the end surface of the first pressure
sensing chamber S1, and the communication between the valve chamber
36 and the oil passage 41 is shut. Thus, when the compressor 10 is
stopped, the circulation of the lubrication oil inside the
compressor 10 is stopped, and the recovery of the lubrication oil
to the suction chamber 25 is stopped.
[0050] According to the fourth embodiment of the present invention,
the similar effects as (1) and (2) of the first embodiment are
obtained, and further, the following advantageous effect (7) is
obtained.
(7) A pair of magnets 44 as an urging member are disposed in the
valve chamber 36 so as to repel each other. The magnets 44 urge the
spool 38 in the direction toward the oil separation mechanism.
Accordingly, utilizing the characteristics of the variation of the
magnetic force in accordance with the temperature of the magnets
44, the characteristics of the relation between the pressure
differential acting on the spool 38 and the opening degree of the
oil passage 41 can be changed in accordance with the temperature of
the refrigerant gas.
[0051] The present invention is not limited to the embodiments
described above but may be modified into the following alternative
embodiments.
[0052] In the first through fourth embodiments, the oil separation
chamber 34 and the valve chamber 36 are integrally formed. In an
alternative embodiment, the oil separation chamber 34 and the valve
chamber 36 may be formed separately and an oil storage chamber 46
is formed therebetween, as shown in FIG. 12.
[0053] In addition to the above alternative embodiment having the
oil storage chamber 45 between the oil separation chamber 34 and
the valve chamber 36, the separated lubrication oil may be supplied
to the second pressure sensing chamber S2, instead of supplying to
the first pressure chamber S1. When the above alternative structure
is applied to the first, third, and the fourth embodiments, the oil
introduction hole 40 may be formed in the side of the second
pressure sensing chamber S2 so as to face the second pressure
sensing chamber S2. When the above alternative structure is applied
to the second embodiment, the oil passage 41 may be formed in the
side of the first pressure sensing chamber S1 so as to face the
first pressure sensing chamber S1.
[0054] In the first through third embodiments, the spring 39 is
disposed in the valve chamber 36 to urge the spool 38 in the
direction toward the end surface of the valve chamber 36. Instead,
the spool 38 and an end surface of the valve chamber 36 may be
connected by a bellows. In this case, considering the
characteristic of bellows, the bellows may be disposed in the first
pressure sensing chamber S1, and not in the second pressure sensing
chamber S2.
[0055] In the first through fourth embodiments, the oil passage 41
is connected to the suction chamber 25 as an oil recovery region
where the separated lubrication oil is supplied. As an alternative,
the oil passage 41, may be connected to the crank chamber 15.
[0056] 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.
* * * * *