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 storagae 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:
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;
FIG. 2 is an enlarged schematic view of a valve mechanism in a state where the valve
mechanism is fully opened;
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;
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;
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;
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;
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;
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;
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;
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;
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
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
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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.
[0018] 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 38 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 introcudtion
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.
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.
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.
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.
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.
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.
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.
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 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 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
[0019] The present invention is not limited to the embodiments described above but may be
modified into the following alternative embodiments.
[0020] 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
45 is formed therebetween, as shown in FIG. 12.
[0021] 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 pessure sensing chamber S1.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
1. A compressor (10) comprising:
an outlet (32) for discharging refrigerant gas out from the compressor (10);
a discharge passage (33) connected to the outlet (32), wherein the refrigerant gas
is discharged through the discharge passage (33) and the outlet (32);
characterized in that
an oil separation mechanism (34, 35) for separating lubrication oil from the refrigerant
gas;
an oil supply passage (34, 36, 40, 41) supplying the separated lubrication oil into
an oil recovery region (15, 25),
a valve mechanism (36, 38, 39) formed in the oil supply passage (34, 36, 40, 41),
wherein the valve mechanism includes a valve chamber (36), a spool (38) and an urging
member (39, 44), wherein the spool (38) separates the valve chamber (36) into a first
pressure sensing chamber (S1) and a second pressure sensing chamber (S2);
wherein the amount of the lubrication oil supplied to the oil recovery region (15,
25) is adjusted in such a manner that as the pressure differential between the first
pressure sensing chamber (S1) and the second pressure sensing chamber (S2) increases,
the spool (38) slides in the valve chamber (36) and the opening degree of the oil
supply passage (34, 36, 40, 41) increases to the maximum and then decreases, and that
when the compressor (10) is stopped, the opening degree of the oil supply passage
(34, 36,40,41) is minimized by the urging force of the urging member (39,44).
2. The compressor according to claim 1, wherein the first pressure sensing chamber (S1)
is connected to a high pressure region and the second pressure sensing chamber (S2)
is connected to a low pressure region.
3. The compressor according to claim 2, wherein the high pressure region includes a discharge
passage (26), and the low pressure region includes a suction chamber (25).
4. The compressor (10) according to any one of claims 1 through 3, wherein the oil recovery
region includes a suction chamber (25).
5. The compressor (10) according to any one of claims 1 through 3, wherein the oil supply
passage includes an oil passage (41) which communicates the valve chamber to the oil
recovery region, wherein an oil introduction hole (40) is formed in the spool (38)
facing the first pressure sensing chamber (S1) so as to face a circumferential surface
of the valve chamber (36) at a side surface thereof, wherein the oil introduction
hole (40) overlaps an opening end of the oil passage (41) formed in a circumferential
surface of the valve chamber (36) when the spool (38) slides, so as to open the oil
supply passage (34, 36, 40, 41), wherein the opening degree of the oil supply passage
(34, 36, 40, 41) is adjusted in accordance with an area where the oil introduction
hole (40) and the opening degree of the oil passage (41) overlap.
6. The compressor (10) according to any one of claims 1 through 4, wherein a groove (42)
is formed on the valve chamber to be positioned so that the first pressure sensing
chamber (S1) and the second pressure sensing chamber (S2) communicate through the
groove (42) when the spool (38) slides so as to open the oil supply passage (34, 36,40,
41).
7. The compressor (10) according to any one of claims 1 through 6, wherein the first
pressure sensing chamber (S1) is connected to an upstream of the oil separation mechanism
(34, 36) and the second pressure sensing chamber (S2) is connected to a downstream
of the oil separation mechanism (34, 36), wherein the spool (38) is moved by the pressure
differential between the upstream and the downstream of the oil separation mechanism
(34, 36).
8. The compressor (10) according to claim 7, wherein the discharge passage (33) has a
branching point connecting to the second pressure sensing chamber (S2), and a check
valve (43) is formed between the branching point and the oil separation mechanism
(34, 36) in the discharge passage (33).
9. The compressor (10) according to any one of claims 1 through 8, wherein the oil separation
chamber (34) is integrally formed with the valve chamber (36).
10. The compressor (10) according to any one of claims 1 through 9, wherein the urging
member (38) is a spring (38).
11. The compressor (10) according to any one of claims 1 through 9, wherein the urging
member (44) is a pair of magnets (44) to be formed to generate repelling force.