Variable-Capacity Compressor

TECHNICAL FIELD

The present invention relates to a variable-displacement compressor, and more specifically, relates to a variable-displacement compressor that varies a discharge displacement of a refrigerant gas by controlling a pressure in a crank chamber by a control valve depending on a pressure in a suction chamber.

BACKGROUND ART

For example, Patent Document 1 discloses this type of a variable-displacement compressor. In the variable-displacement compressor, a control valve is provided in a communication passage communicating between a discharge chamber and a crank chamber on a back side of a piston. The control valve controls a pressure in the crank chamber by controlling an opening of the communication passage depending on a pressure in a suction chamber, and a stroke of the piston is changed. Accordingly, a discharge displacement of a refrigerant gas is varied. Specifically, the suction chamber is connected to the control valve by a pressure introducing passage, and a pressure in the suction chamber is introduced to the control valve. The control valve controls an opening of the communication passage by detecting a change in a pressure in the suction chamber, an amount of a high pressure refrigerant gas to be introduced to the crank chamber is increased or decreased, and a stroke of the piston is changed by changing an inclination (angle of inclination) of a swash plate. Accordingly, a discharge displacement of a refrigerant gas is increased or decreased.

REFERENCE DOCUMENT LIST
Patent Document

Patent Document 1: Japanese Patent Application Laid-open Publication No. 2012-127233

SUMMARY OF THE INVENTION
Problems to be Solved by the Invention

In such a variable-displacement compressor, a lubricating oil is mixed in a refrigerant gas to lubricate each component of the compressor. Therefore, in a configuration like a conventional variable-displacement compressor, in which a refrigerant gas including a lubricating oil to be returned from a suction passage to a suction chamber via an external refrigerant circuit after being discharged from the compressor is directly introduced to a control valve from a pressure introducing passage, sensitivity of the control valve might be lowered since the lubricating oil flows into the control valve especially in a case in which a large amount of the oil is circulating.

The present invention is focused on the above issue and seeks to provide a variable-displacement compressor that can control an amount of a lubricating oil flowing into a control valve and prevent sensitivity reduction of the control valve caused by inflow of the lubricating oil.

Means for Solving the Problems

Therefore, a variable-displacement compressor according to the present invention includes: a piston that compresses a refrigerant gas drawn from a suction chamber via a suction hole and discharges the refrigerant gas to a discharge chamber via a discharge hole; a first passage that communicates between a crank chamber on a back side of the piston and the discharge chamber; a control valve provided in the first passage and that controls an opening of the first passage; a second passage that communicates between the crank chamber and the suction chamber, and that is provided with an orifice; and a pressure introducing passage configured to introduce a pressure in the suction chamber to the control valve. The control valve controls an opening of the first passage depending on the pressure in the suction chamber, which has been introduced from the pressure introducing passage, so as to control a pressure in the crank chamber, so that a stroke of the piston is changed, and accordingly, a discharge displacement of a refrigerant gas is varied. The suction chamber includes a storage area for separating a lubricating oil from a refrigerant gas inflowing from a suction passage and for storing the lubricating oil, and the pressure introducing passage is open to an inflow area into which the refrigerant gas, from which the lubricating oil has been separated, flows, so as to introduce the pressure in the suction chamber to the control valve.

Effect of the Invention

According to the variable-displacement compressor according to the present invention, the suction chamber includes the storage area for storing the lubricating oil separated from the refrigerant gas inflowed from the suction passage, and the pressure introducing passage is open to an inflow area into which the refrigerant gas, from which the lubricating oil has been separated, flows. Therefore, an amount of the lubricating oil in the refrigerant gas flowing into the control valve via the pressure introducing passage can be reduced, and sensitivity reduction of the control valve caused by inflow of the lubricating oil can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating an embodiment of a variable-displacement compressor according to the present invention.

FIG. 2 is a cross-sectional view of a control valve applied to the embodiment.

FIG. 3 is a view illustrating a valve plate viewed from a cylinder block side, according to the embodiment.

FIG. 4 is a view illustrating a discharge valve forming body viewed from a cylinder block side, according to the embodiment.

FIG. 5 is a view illustrating a cylinder head viewed from a cylinder block side, according to the embodiment.

FIG. 6 is a view illustrating a head gasket viewed from a cylinder block side, according to the embodiment.

FIG. 7 is a cross-sectional view taken along with a line A-O-A viewed from arrows A, in a state in which the head gasket illustrated in FIG. 6 is assembled.

FIG. 8 is a cross-sectional view taken along with a line viewed from arrows B, illustrated in FIG. 6.

FIG. 9 is a cross-sectional view taken along with a line viewed from arrows C, in a state in which the cylinder head illustrated in FIG. 5 is assembled.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 illustrates a schematic configuration of a variable-displacement compressor according to a first embodiment of the present invention, and FIG. 1 is an example of a clutch-less variable-displacement compressor for use in a vehicle air conditioning system.

In FIG. 1, a variable-displacement compressor 100 includes: a cylinder block 101 in which multiple cylinder bores 101a are formed; a front housing 102 provided at one end of the cylinder block 101; and a cylinder head 104 provided at another end of the cylinder block 101 via a valve plate 103.

A drive shaft 110 is provided so as to cross in a crank chamber 140 formed by the cylinder block 101 and the front housing 102. A swash plate 111 is arranged around an intermediate portion in an axial direction of the drive shaft 110. The swash plate 111 is connected to a rotor 112, which is fixed to the drive shaft 110, via a linkage 120, and is supported so that an inclination thereof can be varied by the drive shaft 110.

The linkage 120 includes: a first arm 112a arranged so as to protrude from the rotor 112; a second arm 111a arranged so as to protrude from the swash plate 111; and a link arm 121 rotatably connected at one end to the first arm 112a via a first connection pin 122, and rotatably connected at the other end to the second arm 111a via the second connection pin 123.

A through hole 111b of the swash plate 111 is formed so as to be inclined within a range of the maximum inclination (θ max) to the minimum inclination (θ min). A minimum-inclination restricting portion coming into contact with the drive shaft 110 is formed to the through hole 111b. In a case in which an inclination of the swash plate 111 orthogonal to the drive shaft 110 is set as 0°, the minimum inclination restricting portion of the through hole 111b allows the swash plate 111 to be inclined to approximately 0°. The maximum inclination of the swash plate 111 is restricted when the swash plate 111 comes into contact with the rotor 112.

A disinclining spring 114 for biasing the swash plate 111 toward the minimum inclination is mounted around the drive shaft 110 between the rotor 112 and the swash plate 111. Also, an inclining spring 115 for biasing the swash plate 11 in a direction increasing an inclination of the swash plate 111 is mounted around the drive shaft 110 between the swash plate 111 and a spring support member 116 provided to the drive shaft 110. Herein, a biasing force of the inclining spring 115 at the minimum inclination is set to be greater than that of the disinclining spring 114. When the drive shaft 110 is not rotating, the swash plate 111 is arranged at an inclination angle at which the biasing force of the disinclining spring 114 and the biasing force of the inclining spring 115 are balanced.

One end of the drive shaft 110 is extended to an outer side of the front housing 102, passing through a boss portion 102a of the front housing 102, and connected to a power transmission device (not illustrated). A shaft seal device 130 is inserted between the drive shaft 110 and the boss portion 102a to block the inside of the crank chamber 140 from the outside.

The connected body of the drive shaft 110 and the rotor 112 is supported by bearings 131 and 132 in a radial direction and supported by a bearing 133 and a thrust plate 134 in a thrust direction. A gap between the thrust plate 134 of the drive shaft 110 and a portion coming into contact with the thrust plate 134 is adjusted to a predetermined gap by an adjusting screw 135. Power from an external driving source (vehicle engine) is transmitted to a power transmission device, and the drive shaft 110 rotates in synchronization with the power transmission device.

A piston 136 is arranged in the cylinder bore 101a. An outer periphery of the swash plate 111 is accommodated in an internal space of an end portion of the piston 136 protruding toward the crank chamber 140. The swash plate 111 is synchronized with the piston 136 via a pair of shoes 137. Therefore, the piston 136 reciprocates in the cylinder bore 101a by rotation of the swash plate 111.

In the cylinder head 104, a suction chamber 141 defined by an annular partition wall 104b is formed at a center thereof, and a discharge chamber 142 defined by the partition wall 104b and an external wall is formed so that the discharge chamber 142 circularly surrounds the suction chamber 141. The suction chamber 141 is communicated with the cylinder bore 101a via a suction hole 103a formed in the valve plate 103 and a suction valve (not illustrated) formed in a suction valve forming body. The discharge chamber 142 is communicated with the cylinder bore 101a via a discharge hole 103b formed in the valve plate 103 and a discharge valve 138a formed in a discharge valve forming body 138, illustrated in FIG. 4.

A compressor housing is formed by fixing, with multiple through bolts 105, the front housing 102, a center gasket (not illustrated), the cylinder block 101, a cylinder gasket (not illustrated), the suction valve forming body (not illustrated), the valve plate 103 illustrated in FIG. 3, the discharge valve forming body 138 illustrated in FIG. 4, a head gasket 139 illustrated in FIG. 6, and the cylinder head 104 illustrated in FIG. 5.

In the cylinder head 104, a suction passage 104a is formed to communicate between a low pressure side refrigerant circuit (suction side refrigerant circuit) of a vehicle air conditioning system (refrigerant device) and the suction chamber 141. Accordingly, the suction chamber 141 is connected to the low pressure side refrigerant circuit of the refrigerant device. The suction passage 104a is linearly extended so as to cross a part of the discharge chamber 142 toward the suction chamber 141 from the outside of the cylinder head 104.

The suction chamber 141 is partitioned into a first space 141a connected to the suction passage 104a and a second space 141b connected to the suction hole 103a by a partition member 150 integrally formed with the head gasket 139. The first space 141a and the second space 141b are communicated by a communication hole 150a (illustrated in FIG. 6) formed in the partition member 150 as a communication passage. The first space 141a is configured to allow a low pressure refrigerant gas to flow into the first space 141a from a low pressure side refrigerant circuit via the suction passage 104a, and the first space 141a is configured to separate a lubricating oil mixed in the refrigerant gas and to store the separated lubricating oil at a lower side thereof in a gravity direction (bottom portion of the space). Therefore, the first space 141a corresponds to a storage area according to the present invention. The second space 141b is configured to introduce a refrigerant gas, which has flowed into the second space 141b through the communication hole 150a from the first space 141a and separated from a lubricating oil, to the suction hole 103a. Therefore, the second space 141b corresponds to an inflow area according to the present invention. The partition member 150 will be described in detail below.

A muffler 160 for reducing noise and vibration caused by refrigerant pulsation is provided on the cylinder block 101 at an upper portion thereof. The muffler 160 is formed by fixing a lid member 106 with a bolt via a sealing member (not illustrated) to a forming wall 101b divisionally formed at the upper portion of the cylinder block 101. A check valve 200 is arranged in a muffler space 143 in the muffler 160, to reduce a backward flow of a refrigerant gas from a discharge side refrigerant circuit to the discharge chamber 142.

The check valve 200 is arranged at a connecting portion between a communication passage 144 and the muffler space 143, the communication passage 144 extending across the cylinder head 104, the valve plate 103, and the cylinder block 101 and communicating with the discharge chamber 142. The check valve 200 operates in response to a pressure difference between the communication passage 144 (upstream side) and the muffler space 143 (downstream side). When the pressure difference is less than a predetermined value, the check valve 200 blocks the communication passage 144. When the pressure difference is greater than the predetermined value, the check valve 200 opens the communication passage 144. Therefore, the discharge chamber 142 is connected to a discharge side refrigerant circuit of a vehicle air conditioning system via a discharge passage including the communication passage 144, the check valve 200, the muffler space 143, and a discharge port 106a.

In the cylinder head 104, a control valve 300 is provided.

The control valve 300 is provided in a pressure supply passage 145 provided as a first passage that communicates between the discharge chamber 142 and the crank chamber 140 on a back side of the piston 136. The control valve 300 adjusts an opening of the pressure supply passage 145 and controls an amount of the discharge refrigerant gas to be introduced to the crank chamber 140. Also, a refrigerant in the crank chamber 140 flows to the second space 141b of the suction chamber 141 via a pressure releasing passage 146 provided as a second passage that passes through the communication passage 101c, a space 101d, an orifice 103c formed in the valve plate 103 illustrated in FIG. 3, and a communication hole 138b formed in the discharge valve forming body 138 illustrated in FIG. 4. Thus, the control valve 300 changes the pressure in the crank chamber 140, which in turn changes the inclination of the swash plate 111, that is, a stroke of the piston 136. As a result, a discharge displacement of the variable-displacement compressor 100 can be varied. Although the orifice 103c is a fixed orifice in the embodiment, the orifice 103c may be a variable orifice.

The control valve 300 according to the embodiment is a control valve that operates in response to an external electrical signal. FIG. 2 illustrates a configuration thereof.

The control valve 300 includes: a first pressure-sensitive chamber 302 that is formed in a valve housing 301 and communicates with the crank chamber 140 by the pressure supply passage 145 on the crank chamber 140 side via a communication hole 301a; a valve chamber 303 that communicates with the discharge chamber 142 by the pressure supply passage 145 on the discharge chamber 142 side via a communication hole 301b; a valve hole 301c that is open at one end thereof to the first pressure-sensitive chamber 302 and is open at the other end thereof to the valve chamber 303; a valve body 304, one end of which is arranged in the valve chamber 303 and opens and closes the valve hole 301c, the valve body 304 being slidably supported by a support hole 301d formed in the valve housing 301; a bellows assembly 305 that is provided with a spring in an evacuated inside thereof, and is arranged in the first pressure-sensitive chamber 302, the bellows assembly 305 receiving a pressure in the crank chamber 140; a connecting portion 306 that is attachably and detachably connected to the bellows assembly 305 at one end thereof and is fixed to one end of the valve body 304 at the other end thereof; a second pressure-sensitive chamber 307 that is blocked from the valve chamber 303, and in which the other end of the valve body 304 is arranged, the second pressure-sensitive chamber 307 communicating with the second space 141b of the suction chamber 141 by a pressure introducing passage 147, to be described later, via a communication hole 301e; a solenoid rod 304a that is integrally formed with the valve body 304, and in which a movable core 308 is press-fitted at an end portion of the solenoid rod 304a opposite to the valve body 304; a fixed core 309 that is arranged at an outer periphery of the solenoid rod 304a and is arranged to face the movable core 308, being spaced with a predetermined gap; a spring 310 that is interposed between the fixed core 309 and the movable core 308, and elastically biases the valve body 304 in a valve opening direction via the movable core 308 and the solenoid rod 304a; a cylindrical member 312 that is arranged at an outer periphery of the fixed core 309 and fixed to a solenoid housing 311, and that is made of a nonmagnetic material; and an electromagnetic coil 313 that is accommodated in the solenoid housing 311 so as to surround the cylindrical member 312. Also, three O rings 313a to 313c are arranged at an outer periphery of the control valve 300. By the O rings 313a to 313c, a receiving space of the control valve 300 formed in the cylinder head 104 is partitioned into an area in which a pressure in the crank chamber 140 is applied, an area in which a pressure in the discharge chamber 142 is applied, and an area in which a pressure in the suction chamber 141 is applied.

In the control valve 300 having such a configuration, if a bellows effective area Sb of the bellows assembly 305, a pressure receiving area Sv for receiving a pressure in the crank chamber 140 applied to the valve body 304 from the valve hole 301c side, a pressure receiving area Sr for receiving a pressure in the suction chamber 141 (second space 141b) applied to the valve body 304 in the second pressure-sensitive chamber 307 are set to approximately the same value, a force acting on the valve body 304 is represented by the following formula (1):

Ps=−(1/Sb)·F(i)+(F+f)/Sb (1)

where, Ps denotes a pressure in the suction chamber 141 (second space 141b), F(i) denotes an electromagnetic force, f denotes a biasing force of the spring 310, and F denotes a biasing force of the bellows assembly 305.

Therefore, the control valve 300 adjusts an opening of the pressure supply passage 145 communicating between the discharge chamber 142 and the crank chamber 140 so that a pressure Ps in the suction chamber 141 (second space 141b), which has been introduced via the pressure introducing passage 147, is maintained to a predetermined value determined based on a current flowing to an electromagnetic coil 313 in response to an external signal, to thereby control an amount of a discharge refrigerant gas to be introduced to the crank chamber 140, to control a discharge displacement of the variable-displacement compressor 100. The pressure Ps in the suction chamber 141 (second space 141b) can be varied from the outside by adjusting a current flowing to the electromagnetic coil 313.

While an air conditioner is operating, i.e., in a state in which the variable-displacement compressor 100 is operating, an energization amount of the electromagnetic coil 313 is adjusted based on an external signal, a discharge displacement is variably controlled so that a pressure in the suction chamber 141 (second space 141b) becomes a predetermined value and a pressure in the suction chamber 141 is appropriately controlled in response to the external environment. Although the control valve 300 in the embodiment operates in response to an external signal, a mechanical control valve that operates by sensing a pressure in a suction chamber may be used.

Next, the above-described partition member 150 and the pressure introducing passage 147 will be described in detail with reference to FIGS. 3 to 9.

The partition member 150 is integrally formed by making a center of the head gasket 139 illustrated in FIG. 6, i.e., a portion facing the suction chamber 141 at a center of the cylinder head 104, protrude toward the suction chamber 141 by stamping. By the partition member 150, the suction chamber 141 is partitioned into the first space 141a to which the suction passage 104a is connected, and the second space 141b to which the suction hole 103a is connected. In the head gasket 139, a retainer 139a for restricting an opening of the discharge valve 138a is formed in an area corresponding to the discharge chamber 142. The head gasket 139 is a rubber-coated metal thin plate. Therefore, the partition member 150 integrally formed with the head gasket 139 is also rubber-coated.

The second space 141b partitioned by the partition member 150 includes, as illustrated in FIG. 7, a central space 141b1 and guide passages 141b2 radially extended toward the suction holes 103a from the central space 141b1. The guide passage 141b2 includes a bottom wall 150b and side walls 150c as illustrated in FIG. 8. As illustrated in FIG. 7, the guide passage 141b2 includes an area in which the bottom wall 150b is inclined so that a passage sectional area is reduced toward each of the suction holes 103a, which are formed in the valve plate 103 to be annularly arranged at approximately equal intervals around an axis O of the drive shaft 110 at an approximately equal distance from the axis O of the drive shaft 110.

Furthermore, in the partition member 150, two communication holes 150a that communicate between the first space 141a and the second space 141b are formed to be open to two guide passages 141b2 as illustrated in FIG. 6. The communication hole 150a is formed by adjusting the position thereof so that a predetermined amount of a lubricating oil can be stored in the first space 141a. Specifically, the communication hole 150a is open to a position that is above the axis O of the drive shaft 110 in a gravity direction and outside an area on an extension of the suction passage 104a into the suction chamber 141, in order to prevent a main flow of a suction refrigerant, which has flowed into the first space 141a from the suction passage 104a, from directly flowing into the communication hole 150a. Also, an orifice 150d that communicates between the first space 141a and the second space 141b is formed in the bottom wall 150b of the guide passage 141b2 positioned below the axis O of the drive shaft 110 in a gravity direction. An upper side in FIGS. 3 to 6 is an upper side in a gravity direction.

Since the communication hole 150a is located above the axis O of the drive shaft 110 in a gravity direction, the first space 141a acts as an oil storage chamber for storing a lubricating oil returned from an air conditioning system with an inflow refrigerant gas. An opening area of the orifice 150d is set so that an appropriate amount of a lubricating oil is stored in the first space 141a. The orifice 150d acts as an oil return passage, which gradually returns a lubricating oil stored in the first space 141a to the second space 141b. Therefore, the first space 141a acts as a part of the suction passage, the communication hole 150a substantially acts as an exit of the suction passage, and the second space 141b substantially acts as a suction chamber.

Although the communication holes 150a and the orifice 150d (oil return passage) are formed in the partition member 150, these may be formed in the cylinder head 104. Also, the number of the communication holes 150a is not limited to two, and it may be any number as long as it is one or more. Furthermore, although a position of the communication hole 150a is not limited to a position above the axis of the drive shaft 110 in a gravity direction, the communication hole 150a may be positioned at any position as long as it is arranged above the orifice 150d, and the position may be preferably adjusted depending on a target storage amount of lubricating oil in the first space 141a.

Multiple pressing protrusions 104d protruding toward the valve plate 103 are formed on a surface of a suction chamber forming wall of the cylinder head 104 facing the valve plate 103, i.e., on a bottom wall 104c of the suction chamber 141, and are arranged in a substantially annular manner. The pressing protrusions 104d press, toward the valve plate 103, a flat portion 139b of the head gasket 139 formed between the guide passages 141b2 at a periphery of the partition member 150, and accordingly press the valve plate 103 via the head gasket 139 and the discharge valve forming body 138. In this manner, the partition member 150 can be reliably retained on the valve plate 103 side. Herein, the pressing protrusions 104d correspond to a protruded portion according to the present invention.

The pressure introducing passage 147 includes: a communication hole 138c formed in the discharge valve forming body 138; a long hole 103d formed in the valve plate 103; a communication hole 138d formed in the discharge valve forming body 138; a communication hole 139d formed in the head gasket 139; a communication hole 104e formed in the pressing protrusion 104d formed in the cylinder head 104 as illustrated in FIG. 9; and a space 104f partitioned by two O rings 313a and 313b in the receiving space of the control valve 300 in the cylinder head 104, and connected to the communication hole 301e of the control valve 300, as illustrated in FIG. 9. The long hole 103d is closed by a suction valve forming body (not illustrated) arranged between the cylinder block 101 and the valve plate 103.

Therefore, a pressure in the second space 141b of the suction chamber 141 is introduced to the second pressure-sensitive chamber 307 of the control valve 300 via this pressure introducing passage 147 and the communication hole 301e. An open end of the pressure introducing passage 147 on the second space 141b side is the communication hole 138c. The communication hole 138c is arranged above, in a gravity direction, the orifice 150d formed in the partition member 150.

In the variable-displacement compressor having such a configuration, according to the present embodiment, from an inflow refrigerant gas containing a lubricating oil, which has flowed into the first space 141a from the suction passage 104a, the lubricating oil is separated in the first space 141a. The separated lubricating oil is stored in the bottom portion (lower side in a gravity direction) of the first space 141a. The remaining refrigerant gas, from which the lubricating oil has been separated, flows into the second space 141b via the communication hole 150a, and flows toward each suction hole 103a along the guide passages 141b2, and then is drawn into the cylinder bore 101a from each suction hole 103a by the reciprocation of the piston 136.

In this manner, since what flows into the second space 141b of the suction chamber 141 is the remaining refrigerant gas, from which the lubricating oil has been separated, an amount of the lubricating oil flowing into the second pressure-sensitive chamber 307 of the control valve 300, to which a pressure in the second space 141b is introduced via the pressure introducing passage 147, can be reduced.

Therefore, the inside of the control valve 300, especially the second pressure-sensitive chamber 307 and the inside of the cylindrical member 312 communicating with the second pressure-sensitive chamber 307, are not filled with the lubricating oil, and sensitivity of the control valve 300 is not reduced by operation failure caused by inflow of the lubricating oil.

Also, since the communication hole 138c, which is an open end of the pressure introducing passage 147 on the second space 141b side, is arranged above, in a gravity direction, the orifice 150d formed in the partition member 150, when the lubricating oil stored in the first space 141a is returned to the second space 141b via the orifice 150d, the lubricating oil does not flow into the pressure introducing passage 147, and control operation of the control valve 300 is not interrupted. The lubricating oil gradually flowing into the second space 141b from the first space 141a by the orifice 150d contributes to lubricate each component of the variable-displacement compressor 100.

The lubricating oil separated from the refrigerant gas is drawn into the cylinder bore 101a, and therefore an oil flowing out from the variable-displacement compressor 100 toward an air conditioning system is reduced. Accordingly it contributes to reduce an oil circulation rate.

Furthermore, since each suction hole 103a is partitioned by the guide passages 141b2 radially formed from the central space 141b1, the refrigerant gas smoothly flows toward each suction hole 103a, and thus, mutual interference of a refrigerant gas toward each suction hole 103a is prevented. Accordingly it contributes to reduce a pulsation level of a suction pressure.

In the present embodiment, since the partition member 150 is integrally formed with the head gasket 139 by stamping the head gasket 139, an additional new component as a partition member is not needed, and a structure for fixing the partition member 150 in the suction chamber 141 is not needed. As a result, a cost increase by employing the partition member 150 can be suppressed.

In the present embodiment, the partition member 150 is integrally formed with the head gasket 139. However, the partition member 150 may be formed to be a member separated from the head gasket 139.

Furthermore, in the present embodiment, the lubricating oil stored in the first space 141a is returned to the second space 141b by the orifice 150d. However, the first space 141a and the crank chamber 140 may be communicated by an oil return passage. In this manner, even when the variable-displacement compressor 100 stops rotating, oil stored in the first space 141a can be returned to the crank chamber 140.

Although the communication hole 150a is provided in the embodiment as a communication passage for introducing the refrigerant gas, from which the oil has been separated, to the second space 141b, a cylindrical communication passage protruding to the first space 141a may be provided instead of the hole. This may improve an oil separation effect in the first space 141a.

Although an example of a clutch-less compressor as the variable-displacement compressor 100 is illustrated in the embodiment, an electromagnetic clutch may be mounted on a variable-displacement compressor. The present invention is not limited to a swash plate type, and it is applicable to a swing-plate type variable-displacement compressor.

REFERENCE SYMBOL LIST

100 Variable-displacement compressor

103
a Suction hole

103
c Orifice

104
a Suction passage

136 Piston

140 Crank chamber

141 Suction chamber

141
a First space

141
b Second space

142 Discharge chamber

145 Pressure supply passage (first passage)

146 Pressure releasing passage (second passage)

147 Pressure introducing passage

150 Partition member

150
a Communication hole

300 Control valve

Variable-Capacity Compressor

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CPC

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