JP2008144701A - Variable displacement reciprocating compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement reciprocating compressor in which the temperature of a refrigerant discharged therefrom is prevented from surpassing the upper limit value by a simple structure. <P>SOLUTION: This variable displacement reciprocating compressor comprises a capacity control valve 95 inserted into a low-pressure communication passage for joining a crankcase and a suction chamber 90 to each other, a pressure actuator for opening and closing the capacity control valve 95 for making the discharged amount of a working fluid discharged from the compressor to the outside to approach a requested value requested by the compressor, a temperature actuator 98 mechanically operated by reacting to the temperature of a refrigerant in a discharge chamber 85, and an overheat prevention valve 99 opened and closed by the temperature actuator 98 and raising the pressure of the crankcase 26 when the temperature of the working fluid in the discharge chamber 85 approaches the upper limit temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a variable displacement reciprocating compressor.

  The variable capacity reciprocating compressor is incorporated in a refrigeration circuit of a vehicle air conditioner, for example. Specifically, the refrigeration circuit includes a circulation path through which the refrigerant circulates, and a compressor, a radiator, an expander, and an evaporator are sequentially inserted in the circulation path. The compressor executes a series of processes including refrigerant suction, compression, and discharge steps, and power is supplied to the compressor from the engine, for example, via an electromagnetic clutch.

In a refrigeration circuit, when the amount of refrigerant charged is insufficient, when the heat load on the evaporator is large, or when the engine speed is high, the The temperature of the compressed refrigerant (discharge temperature) also increases. An abnormal increase in the discharge temperature not only lowers the durability of the refrigeration circuit, but may lead to seizure of the compressor.
Conventionally, various techniques for preventing seizure of a compressor have been developed. For example, the clutchless compressor of Patent Document 1 increases the discharge capacity of the compressor when the difference between the temperature of the compressor body and the outside air temperature becomes larger than a predetermined value when the discharge capacity of the compressor is minimum. Increase the circulation rate of the refrigerant. Thereby, it is considered that the seizure of the compressor is prevented when the refrigerant circulation amount is insufficient.
JP-A-6-323248

  By the way, when the temperature of the compressor body and the outside air temperature are measured by the temperature sensor as in Patent Document 1, not only the temperature sensor is installed, but also an amplifier that amplifies the electrical signal from the temperature sensor, and the amplifier It is necessary to provide a control device for determining the signal and operating the solenoid valve. Thus, in the clutchless compressor of patent document 1, since everything from the detection of the temperature by a temperature sensor to the action | operation of a solenoid valve is electrically performed, a structure is complicated.

  The present invention has been made based on the above-described circumstances, and an object of the present invention is to provide a variable capacity reciprocating compression in which the temperature of the discharged refrigerant is prevented from exceeding the upper limit value with a simple configuration. Is to provide a machine.

  In order to achieve the above object, according to the present invention, the swash plate tilts with respect to the rotation shaft in accordance with the crank chamber pressure, and the stroke length corresponding to the tilting of the swash plate with the rotational movement of the swash plate. A piston that reciprocates to perform a suction step of the working fluid from the suction chamber to the cylinder bore, a compression step of the working fluid in the cylinder bore, and a discharge step of the working fluid from the cylinder bore to the discharge chamber; and the discharge A high-pressure communication path that connects the chamber and the crank chamber, a low-pressure communication path that connects the crank chamber and the suction chamber, and a capacity control that is inserted into one of the high-pressure communication path and the low-pressure communication path A capacity that includes a valve, changes the pressure of the crank chamber by opening and closing the capacity control valve, and brings the discharge amount of the working fluid discharged from the compressor to the required value required for the compressor And a temperature actuator that operates mechanically in response to the temperature of the refrigerant in the discharge chamber, and overheats to increase the pressure in the crank chamber when the temperature of the working fluid in the discharge chamber approaches the upper limit temperature. And a variable capacity reciprocating compressor characterized by comprising a prevention means.

Preferably, the temperature actuator includes a heat sensitive material whose volume or shape changes with a change in temperature of the working fluid.
Preferably, the heat sensitive material is a wax (claim 3).
Preferably, the temperature actuator has a bellows that expands and contracts as the volume of the heat sensitive material changes.

  Preferably, the heat-sensitive material is a bimetal (Claim 5).

The variable capacity reciprocating compressor according to claim 1 of the present invention is provided with overheat prevention means, and the temperature of the working fluid discharged from the compressor does not exceed the upper limit temperature by the action of the overheat prevention means. For this reason, the seizure of the compressor is prevented, and the durability of the system to which the compressor is applied is improved.
The overheat prevention means of the variable capacity reciprocating compressor has a temperature actuator, and the temperature actuator mechanically operates in response to the temperature of the refrigerant in the discharge chamber. For this reason, compared with the case where the temperature of a compressor etc. is electrically detected with a temperature sensor, the overheat prevention means has a simple configuration.

In the variable capacity reciprocating compressor according to claim 2, the temperature actuator includes a heat sensitive material, and one of the heat sensitive material changes in volume and shape in accordance with the temperature change of the working fluid. Since the volume or shape of the heat-sensitive material is surely changed with the temperature change of the working fluid, the overheat preventing means of the compressor is excellent in reliability.
In the variable capacity type reciprocating compressor of claim 3, the heat sensitive material is wax, and the volume of the wax surely changes with the temperature change of the working fluid. For this reason, the overheat prevention means of this compressor is excellent in reliability.

  In the variable capacity reciprocating compressor according to the fourth aspect, the temperature actuator includes a bellows, and the bellows expands and contracts as the volume of the heat-sensitive material changes. By using the bellows, leakage of the heat sensitive material is prevented even if the heat sensitive material is in a liquid phase or a gas phase. If a large volume change due to a phase change of the heat sensitive material is used while preventing leakage of the heat sensitive material, the temperature actuator operates stably. As a result, the overheat prevention means of this compressor is excellent in reliability.

  In the variable capacity reciprocating compressor according to the fifth aspect, the heat sensitive material is bimetal, and the shape of the bimetal surely changes as the temperature of the working fluid changes. For this reason, the overheat prevention means of this compressor is excellent in reliability.

  FIG. 1 shows a variable capacity reciprocating compressor according to a first embodiment together with a refrigeration circuit 10 of a vehicle air conditioning system. The refrigeration circuit 10 includes a circulation path 12 through which a refrigerant as a working fluid circulates. A compressor, a radiator (condenser) 14, an expander (expansion valve) 16, and an evaporator 18 are sequentially inserted into the circulation path 12 in the flow direction of the refrigerant, and when the compressor operates, the circulation path 12 The refrigerant circulates. That is, the compressor performs a series of processes including a refrigerant suction process, a suction refrigerant compression process, and a compressed refrigerant discharge process.

The compressor is shown as a rocking plate type compressor and includes a cylinder block 20. A peripheral wall 22 is integrally formed on one end side of the cylinder block 20, and a front housing 24 is airtightly joined to an opening end of the peripheral wall 22. One end face of the cylinder block 20, the peripheral wall 22, and the front housing 24 define a crank chamber 26.
A drive shaft 30 is disposed in the center of the crank chamber 26, and the drive shaft 30 passes through the front housing 24 and a cylindrical bearing support portion 31 formed integrally with the outer surface of the front housing 24. A boss 34 constituting the driven side unit of the electromagnetic clutch 32 is fixed to the outer end of the drive shaft 30 protruding from the bearing support portion 31, and the drive pulley 36 constituting the drive side of the electromagnetic clutch 32 is fixed to the bearing support portion 31. Is supported rotatably via a bearing 38. Therefore, when the electromagnetic clutch 32 is turned on, the power of the engine (not shown) is transmitted to the drive shaft 30 via the drive pulley 36.

The inner end of the drive shaft 30 is located in a shaft hole 40 that passes through the center of the cylinder block 20. The drive shaft 30 is rotatably supported by the front housing 24 and the cylinder block 20 via radial bearings 42 and 44.
Further, for example, seven cylinder bores 50 are concentrically formed in the cylinder block 20 with the shaft hole 40 as the center. These cylinder bores 50 are arranged at equal intervals in the circumferential direction of the cylinder block 20, and each cylinder bore 50 penetrates the cylinder block 20 in a direction parallel to the drive shaft 30, that is, in the axial direction of the cylinder block 20.

A piston 52 is slidably fitted in each cylinder bore 50, and a connecting rod 54 is connected to each piston 52 via a ball joint. The connecting rod 54 protrudes into the crank chamber 26, and the end of the connecting rod 54 is connected to the outer peripheral portion of the annular swing plate 56 via a ball joint.
In order to reciprocate the piston 52, in other words, to swing the swing plate 56, the rotor 60 is fixed to the drive shaft 30 coaxially so as not to be relatively rotatable. A thrust bearing is disposed between the rotor 60 and the front housing 24, and an annular swash plate 64 is connected to the rotor 60 via a hinge 62 so as to be tiltable.

The swash plate 64 has an annular shape and is penetrated by the drive shaft 30. A cylindrical swash plate boss 65 surrounding the drive shaft 30 is integrally formed on the inner peripheral edge of the swash plate 64, and a return spring 66 is disposed between the tip of the swash plate boss 65 and the cylinder block 20. The return spring 66 biases the swash plate boss 65 toward the rotor 60.
Further, a sleeve 67 is disposed inside the swash plate boss 65, and the sleeve 67 is slidably fitted to the drive shaft 30. The sleeve 67 is pin-coupled to the swash plate boss 65 and guides the tilting of the swash plate boss 65.

The swash plate 64 and the swash plate boss 65 support the swinging plate 56 through a thrust bearing 69 and a radial bearing 70 so as to be relatively rotatable. A balance ring 71 is also fitted to the swash plate boss 65, and the balance ring 71 constitutes a retaining plate for the swing plate 56.
The swing plate 56 is provided with a rotation prevention mechanism that prevents the swing plate 56 from rotating. The rotation prevention mechanism includes a slider 72 fixed to the swing plate 56, and a guide rail 74 sandwiched between the front housing 24 and the cylinder block 20. As the drive shaft 30 rotates, the slider 72 reciprocates in the guide rail 74 while preventing rotation around the drive shaft 30.

A cylinder head 82 is joined to the other end side of the cylinder block 20 by a plurality of connecting bolts 83 via a gasket (not shown) and a valve plate 80.
A discharge port 84 is formed in the cylinder head 82. The discharge port 84 communicates with the radiator 14 through the circulation path 12 and communicates with a discharge chamber 85 defined in the cylinder head 82. The discharge chamber 85 communicates with the cylinder bore 50 through a discharge hole 86 formed in the valve plate 80, and the discharge hole 86 is opened and closed by a discharge valve. The discharge valve includes a reed valve body 87 and a valve retainer 88.

In addition, a suction port 89 is formed in the cylinder head 82. The suction port 89 communicates with the evaporator 18 through the circulation path 12 and also communicates with the suction chamber 90 defined in the cylinder head 82. The suction chamber 90 communicates with the cylinder bore 50 through a suction hole 91 formed in the valve plate 80, and the suction hole 91 is opened and closed by a suction valve (not shown).
In the compressor described above, the amount of refrigerant discharged from the discharge port 84 (discharge amount) changes according to the pressure in the crank chamber 26. That is, according to the pressure in the crank chamber 26, the inclination angle of the swash plate 64 and the swing plate 56 with respect to the drive shaft 30 changes, and the stroke length of the piston 52 changes.

In order to change the discharge capacity of the compressor by adjusting the pressure in the crank chamber 26, the discharge chamber 85 and the crank chamber 26 communicate with each other through a communication path (high pressure communication path), and a part of the high pressure communication path is The through hole 92 is formed through the cylinder block 20.
On the other hand, the crank chamber 26 and the suction chamber 90 communicate with each other through a low pressure communication path. The low-pressure communication path includes a shaft hole 40 of the cylinder block 20, a communication groove 93 formed on the other end surface of the cylinder block 20, and a gas vent hole 94 formed in the valve plate 80.

A capacity control valve 95 is disposed in the shaft hole 40. The capacity control valve 95 has an internal flow path (valve path) that constitutes a part of the low-pressure communication path, and the valve path is opened and closed by a valve body. The opening / closing operation of the valve body is executed by a pressure actuator attached to the capacity control valve 95, and the pressure actuator has a push rod 96 that penetrates the valve plate 80.
The pressure actuator opens and closes the valve path of the capacity control valve 95 so that the discharge amount approaches the required value required for the compressor. The required value increases or decreases in accordance with the refrigerant pressure (suction pressure) in the suction chamber 90, which is an index of the heat load on the evaporator 18. Specifically, the pressure actuator operates based on the refrigerant pressure (discharge pressure) in the discharge chamber 85 detected through the push rod 96, the refrigerant pressure and the suction pressure in the crank chamber 26, and the suction pressure is lower than the target value. If it is too low, the valve is closed. When the valve path is closed, the pressure in the crank chamber 26 increases, the inclination angle of the swing plate 56 becomes smaller, and the stroke length of the piston 52 becomes shorter. As a result, the discharge amount decreases and the suction pressure increases.

The target value of the suction pressure is a value set according to the specifications of the refrigeration circuit 10, and can be changed as appropriate depending on the configuration of the temperature actuator.
In addition, the compressor described above is provided with overheat prevention means for increasing the pressure in the crank chamber 26 and reducing the discharge amount when the temperature of the refrigerant in the discharge chamber 85 (discharge temperature) approaches the upper limit value. The overheat protection means, which is shown schematically in FIG. 1 at block 97, has a temperature actuator 98 as shown in detail in FIGS. The temperature actuator 98 is mechanically operated in response to the discharge temperature.

The overheat prevention means has an overheat prevention valve 99 inserted in the communication groove 93, and the overheat prevention valve 99 driven by the temperature actuator 98 opens and closes the communication groove 93.
More specifically, the temperature actuator 98 has an actuator housing 100 that is fixed to the valve plate 80. The actuator housing 100 is preferably made of metal. A bimetal 102 is accommodated in the actuator housing 100, and the bimetal 102 is positioned near the end wall of the actuator housing 100. The bimetal 102 is disposed substantially parallel to the valve plate 80, and both ends of the bimetal 102 are constrained in the actuator housing 100. The base of the push rod 104 comes into contact with the center of the bimetal 102 from the valve plate 80 side, and the push rod 104 protrudes into the communication groove 93 through a through hole formed in the valve plate 80.

The bimetal 102 is formed by bonding two types of metal plates having different linear expansion coefficients. When the discharge temperature transmitted to the bimetal 102 via the actuator housing 100 rises, the bimetal 102 is bent so that the central portion swells toward the valve plate 80 as shown in FIG.
On the other hand, an overheat prevention valve 99 is disposed in the communication groove 93, and the valve casing 106 of the overheat prevention valve 99 divides the communication groove 93 into an upstream and a downstream as viewed in the flow direction of the refrigerant. An inlet 108 that opens to the upstream side of the valve casing 106 and an outlet 110 that opens to the downstream side of the valve casing 106 are formed on the outer peripheral surface of the valve casing 106, and the valve casing is between the inlet 108 and the outlet 110. Communication is possible through a valve chamber in 106.

However, a cylindrical valve body 112 is slidably disposed in the valve chamber, and the inlet 108 and the outlet 110 can be opened and closed on the outer peripheral surface of the valve body 112. The valve body 112 is fitted to the tip of the push rod 104 of the temperature actuator 98 described above, and opens and closes the inlet 108 and the outlet 110 of the valve casing 106 as the tip of the push rod 104 reciprocates.
A return spring 114 is disposed between the valve body 112 and the end wall of the valve casing 106. When the bimetal 102 becomes flat from the curved state, the valve body 112 is pushed back toward the valve plate 80 by the return spring 114, and is positioned from the closed position to the open position.

Hereinafter, the operation of the above-described compressor will be described.
When the electromagnetic clutch 32 is turned on, power from the engine is transmitted to the drive shaft 30 and the drive shaft 30 rotates. As the drive shaft 30 rotates, the rotor 60, the hinge 62, the swash plate 64, and the swash plate boss 65 also rotate, and the swing plate 56 supported so as to be rotatable relative to the swash plate 64 and the swash plate boss 65 swings. . The swing of the swing plate 56 is converted into the reciprocating motion of the piston 52 through the ball joint and the connecting rod 54, and the reciprocating motion of the piston 52 causes the refrigerant suction process from the suction chamber 90 to the cylinder bore 50, The refrigerant compression step and the refrigerant discharge step from the cylinder bore 50 to the discharge chamber 85 are executed. That is, due to the reciprocating motion of the piston 52, the refrigerant vaporized in the evaporator 18 is sucked into the compressor through the circulation path 12 and the suction port 89, and the refrigerant discharged from the discharge port 84 of the compressor is passed through the circulation path 12 to the radiator 14 To be supplied.

The stroke length of the piston 52 is variable according to the pressure in the crank chamber 26. Therefore, the amount of refrigerant discharged from the compressor (discharge amount) is also variable.
The discharge amount of the refrigerant is controlled so as to approach the required value required by the refrigeration circuit 10 for the compressor, and the required value increases or decreases corresponding to the refrigerant pressure (suction pressure) in the suction chamber 90. That is, the suction pressure is an index of the heat load applied to the evaporator 18, and the required value increases as the suction pressure increases, and the required value decreases as the suction pressure decreases.

  As a capacity control means for bringing the discharge amount close to the required value, the pressure actuator opens and closes the capacity control valve 95 based on the pressure in the suction chamber 90 as shown in FIG. As a result, the flow rate of the refrigerant discharged from the crank chamber 26 to the suction chamber 90 through the low pressure communication path changes, and the pressure in the crank chamber 26 increases or decreases. Specifically, when the suction pressure decreases, the pressure actuator closes the displacement control valve 95 to increase the pressure in the crank chamber 26 and decrease the discharge amount. On the other hand, when the suction pressure rises, the pressure actuator opens the capacity control valve 95 to reduce the pressure in the crank chamber 26 and increase the discharge amount.

  As described above, the compressor normally discharges the refrigerant at a discharge amount required from the refrigeration circuit 10. On the other hand, the temperature (discharge temperature) of the refrigerant in the discharge chamber 85 of the compressor increases due to an increase in the heat load applied to the evaporator 18, an increase in the engine speed, a shortage of the amount of refrigerant enclosed, and the like. When the upper limit value is approached, the discharge temperature is lowered by the function of the overheat prevention means different from the capacity control means.

  Specifically, the overheat prevention means includes an overheat prevention valve 99 and a temperature actuator 98 inserted in the low pressure communication path. When the discharge temperature approaches the upper limit value, the bimetal 102 of the temperature actuator 98 is bent so that the central portion protrudes toward the valve plate 80, thereby pushing the push rod 104. When the push rod 104 is pushed by the bimetal 102, the valve body 112 attached to the tip of the push rod 104 moves to the closed position and closes the inlet 108 and the outlet 110 formed in the valve casing 106 of the overheat prevention valve 99. . In this state, the communication groove 93 of the low pressure communication path is closed by the overheat prevention valve 99, and the pressure in the crank chamber 26 increases even if the capacity control valve 95 is open. As a result, the discharge amount decreases and the discharge temperature also decreases.

Thereafter, when the discharge temperature is lowered, the bimetal 102 is deformed so that the central portion thereof is flat, and the push rod 104 is pushed back by the urging force of the return spring 114. Along with this, the valve body 112 moves to the open position, the inlet 108 and the outlet 110 of the valve casing 106 are opened, and the communication groove 93 of the low pressure communication path is opened.
The upper limit temperature of the discharge temperature is set in consideration of the seizure of the compressor and the durability of the parts used in the refrigeration circuit 10, and is set in the range of 110 ° C. or higher and 160 ° C. or lower, for example.

Thus, in the compressor mentioned above, the temperature of the refrigerant | coolant discharged from a compressor does not exceed upper limit temperature by the effect | action of an overheat prevention means. For this reason, the seizure of the compressor is prevented, and the durability of the refrigeration circuit 10 to which the compressor is applied is improved. In particular, when the refrigerant contains a thermally unstable component such as CF ₃ I, the deterioration of the refrigerant is prevented.
The above-described overheat preventing means of the compressor has a temperature actuator 98, and the temperature actuator 98 is mechanically operated in response to the temperature of the refrigerant in the discharge chamber 85. For this reason, compared with the case where the temperature of a compressor etc. is electrically detected with a temperature sensor, the overheat prevention means has a simple configuration.

Further, in the above-described compressor, the temperature actuator 98 includes the bimetal 102 as a heat sensitive material for detecting the discharge temperature, and the shape of the bimetal 102 changes as the temperature of the refrigerant changes. Since the shape of the bimetal 102 is surely changed with the temperature change of the refrigerant, the overheat preventing means of the compressor is excellent in reliability.
In the compressor described above, since the actuator housing 100 of the temperature actuator 98 is made of metal, the temperature of the refrigerant is reliably transmitted to the bimetal 102 through the actuator housing 100 regardless of the discharge pressure.

The present invention is not limited to the first embodiment described above, and various modifications are possible. For example, the number of cylinder bores 50 in the compressor is not limited to seven.
Although the compressor of the first embodiment is a swing plate type compressor, the compressor of the present invention can also be applied to other reciprocating compressors such as a swash plate type compressor. . In the case of a swash plate type compressor, a tail portion is formed integrally with the piston 52, and the tail portion projects into the crank chamber 26. A spherical seat is formed in each tail portion, and a pair of hemispherical shoes arranged on the spherical seat are in sliding contact with the outer peripheral portion of the swash plate.

Further, the configurations of the overheat prevention valve 99 and the temperature actuator 98 are not particularly limited as long as the pressure in the crank chamber 26 can be mechanically increased when the discharge temperature approaches the upper limit value.
For example, FIG. 5 schematically shows the temperature actuator 120 and the overheat prevention valve 122 according to the second embodiment.
The overheat prevention valve 122 is disposed in the discharge chamber 85 and is integrated with the temperature actuator 120. That is, the overheat prevention valve 122 is surrounded by the actuator housing 124 of the temperature actuator 120, and the inlet 128 and the outlet 130 of the valve casing 126 of the overheat prevention valve 122 are respectively connected to an inlet hole or an outlet hole formed in the valve plate 80. Yes. The push rod 104 of the temperature actuator 120 penetrates not the valve plate 80 but the end wall of the valve casing 126 of the overheat prevention valve 122.

A partition wall 132 that partitions the communication groove 93 into the upstream and the downstream is integrally formed on the end surface of the cylinder block 20, and the opening of the inlet hole and the outlet hole formed in the valve plate 80 is formed on the partition wall 132. Located on both sides.
Further, in the first embodiment described above, the compressor is an internal control type variable displacement type and controls the pressure in the crank chamber 26 on the outlet side (outlet control). An internal control type variable displacement type may be used which controls the pressure in the crank chamber 26 on the inlet side (inlet control).

  For example, FIG. 6 shows, as a third embodiment, an external control system and a capacity control means and overheating prevention in a variable capacity reciprocating compressor of a system in which the pressure in the crank chamber 26 is controlled (inlet control) on the inlet side. A schematic configuration of the means is shown together with an external control device. The capacity control valve 140 fixed to the cylinder head 82 is inserted into a high pressure communication path (first high pressure communication path), and an orifice 142 is provided in the low pressure communication path. The capacity control valve 95 is driven to open and close by a solenoid 144, and the solenoid 144 is controlled by a control signal from the control device 146.

As in the case of the internal control method (exit control), the control device 146 controls the solenoid 144 so that the discharge amount of the compressor approaches the required value required for the compressor. For this purpose, for example, a pressure signal from a temperature sensor 148 provided in the suction chamber 90 is input to the control device 146, and the control device increases or decreases the discharge amount in accordance with the pressure in the suction chamber 90.
In the case of the external control system (inlet control), a second high-pressure communication path that bypasses the capacity control valve 140 and connects between the discharge chamber 85 and the crank chamber 26 is formed as an overheat prevention means. An overheat prevention valve 150 is inserted in the passage. That is, in the case of the outlet control method, the overheat prevention valve 99 is inserted in series with the capacity control valve 95 in the low pressure communication path, but in the case of the inlet control method, the overheat prevention valve 150 is in parallel with the capacity control valve 140. Is provided.

In the case of the inlet control system, the difference between the series and the parallel is that the pressure of the crank chamber 26 is increased by increasing the amount of refrigerant supplied from the discharge chamber 85 to the crank chamber 26, whereas In the case of the outlet control method, the pressure in the crank chamber 26 is increased by decreasing the amount of refrigerant discharged from the crank chamber 26 to the suction chamber 90.
As the overheat prevention valve 150 and the temperature actuator 152, the same ones as in the first embodiment can be used as shown in FIG. However, the valve casing 106 of the overheat prevention valve 99 is disposed in the communication groove 154 of the cylinder block 20 constituting a part of the second high-pressure communication path, and the first high-pressure communication path and the second high-pressure communication path are The through hole 92 formed in the cylinder block 20 is shared.

In addition, although another through-hole may be formed in the cylinder block 20 for the second high-pressure communication path, the first high-pressure communication path and the second high-pressure communication path are formed in the cylinder block 20. By sharing the hole 92, the configuration becomes simpler.
In the first to third embodiments described above, although the overheat prevention valve and the temperature actuator are fixed to the valve plate 80, the discharge chamber 162 and the suction chamber 164 are only shown in FIG. May be fixed to the partition wall 166 of the cylinder head 82.

  FIG. 9 shows in detail the periphery of the portion indicated by block 160 in FIG. 8, that is, shows the temperature actuator 168 and the overheat prevention valve 170 according to the fourth embodiment. The overheat prevention valve 170 has a block-shaped valve casing 172 fixed to the partition wall 166. A valve hole 174 is formed in the valve casing 172, and the valve hole 174 passes through the valve casing 172. An internal flow path formed in the cylinder head 82 communicates with one end of the valve hole 174, and the internal flow path is connected to a through hole 92 formed in the valve plate 80 and the cylinder block 20.

The root of the reed valve body 178 is fixed to the end surface of the valve casing 172 by a screw 176, and the opening of the valve hole 174 can be airtightly closed by the elastic force of the reed valve body 178 at the center of the reed valve body 178. is there. The leading end of the reed valve body 178 protrudes from the end surface of the valve casing 172, and the push rod 180 of the temperature actuator 168 is in contact with the leading end of the reed valve body 178.
The actuator housing 182 of the temperature actuator 168 is fixed to the partition wall 166 along with the valve casing 172 of the overheat prevention valve 170, and the tip of the push rod 180 of the temperature actuator 168 protrudes through the end wall of the actuator housing 182. Yes. The push rod 180 passes through a bellows 184 fixed to the inside of the end wall, and the bellows 184 divides the inside of the actuator housing 182 into an inner space and an outer space of the bellows 184 in an airtight manner.

In the space outside the bellows 184 in the actuator housing 182, a substance 186 in a gas-liquid mixed state is accommodated as a heat sensitive material for detecting the discharge temperature. As such a substance 186, the same chlorofluorocarbon as the refrigerant is used. Can do.
According to this temperature actuator 168, when the discharge temperature rises, the liquid phase component of the gas-liquid mixed material is vaporized, the pressure (volume) increases, and the bellows 184 contracts. The bellows 184 is sandwiched between the inner end of the push rod 180 and the end wall of the actuator housing 182. When the bellows 184 contracts, the protruding length of the push rod 180 from the end wall of the actuator housing 182 increases.

As the protrusion length of the push rod 104 increases, the tip of the reed valve body 178 is pushed in the valve opening direction, and the central portion of the reed valve body 178 is separated from the opening end of the valve hole 174. As a result, the discharge chamber 85 and the crank chamber 26 communicate with each other, and the pressure in the crank chamber 26 increases.
As is clear from a comparison between FIG. 1 and FIG. 8, either the suction chamber 90 may surround the discharge chamber 85 or the discharge chamber 162 may surround the suction chamber 164.

  In the fourth embodiment, the temperature actuator 168 includes a bellows 184, and the bellows 184 expands and contracts as the heat sensitive material changes in volume. By using the bellows 184, leakage of the heat sensitive material is prevented even if the heat sensitive material is in a liquid phase or a gas phase. The temperature actuator 168 operates stably by utilizing a large volume change due to the phase change of the heat sensitive material while preventing leakage of the heat sensitive material. As a result, this overheating prevention means is excellent in reliability.

In the fourth embodiment described above, the gas-liquid mixed material 186 is used as a heat sensitive material whose volume increases or decreases due to temperature change, and the bellows 184 is used as a conversion means for converting the volume increase or decrease into the displacement of the push rod 104. However, the type of heat sensitive material and the conversion means are not particularly limited.
For example, FIG. 10 shows a temperature actuator 190 according to the fifth embodiment. In the temperature actuator 190, an actuator housing 192 is divided into two spaces by a diaphragm 194 as a conversion means. A space opposite to the push rod 196 defined by the diaphragm 194 is filled with wax 198 as a heat sensitive material.

According to the temperature actuator 190, the center portion of the diaphragm 194 bulges as the wax 198 expands. As the diaphragm 194 bulges, the push rod 196 is pushed, the protrusion length of the push rod 196 increases, and the overheat prevention valve is opened.
In the fifth embodiment, the heat sensitive material is the wax 198, and the volume of the wax 198 surely changes as the temperature of the refrigerant changes. For this reason, the overheat prevention means using this heat sensitive material is excellent in reliability.

  Finally, the variable capacity reciprocating compressor of the present invention can be applied to various systems other than the vehicle air conditioning system, and the working fluid is not limited to the refrigerant.

It is the figure which showed the variable capacity type reciprocating compressor of 1st Embodiment with the freezing circuit of the vehicle air conditioning system. It is sectional drawing which shows the open operation state of the temperature actuator applied to the compressor of FIG. 1, and an overheat prevention valve. It is sectional drawing which shows the closed operation state of the temperature actuator applied to the compressor of FIG. 1, and an overheat prevention valve. It is a block diagram which shows the outline of the capacity | capacitance control means and overheat protection means which were applied to the compressor of FIG. It is sectional drawing shown in the state which applied the temperature actuator and overheat prevention valve concerning 2nd Embodiment to the compressor. It is a block diagram which shows the outline of the capacity | capacitance control means and overheat protection means which are applied to the variable capacity type reciprocating compressor of the external control system of 3rd Embodiment. It is sectional drawing shown in the state which applied the temperature actuator and overheat prevention valve as an overheat protection means of FIG. 6 to the compressor. It is a figure which shows schematically the cross section of the cylinder head of the compressor of 4th Embodiment. It is a figure which expands and shows a part of FIG. 8 in detail. It is a figure which shows the cross section of the temperature actuator concerning 5th Embodiment.

Explanation of symbols

85 Discharge chamber
90 Suction chamber
95 Capacity control valve
98 Temperature actuator
99 Overheat prevention valve

Claims (5)

A swash plate that tilts relative to the rotating shaft in response to the pressure in the crank chamber;
As the swash plate rotates, the reciprocating motion is performed with a stroke length corresponding to the tilt of the swash plate, the step of sucking the working fluid from the suction chamber into the cylinder bore, the step of compressing the working fluid in the cylinder bore, and the cylinder bore A piston for performing the discharge process of the working fluid from the discharge chamber to the discharge chamber;
A high-pressure communication path connecting the discharge chamber and the crank chamber;
A low-pressure communication path connecting the crank chamber and the suction chamber;
The operation that includes a capacity control valve inserted in one of the high-pressure communication path and the low-pressure communication path, changes the pressure of the crank chamber by opening / closing operation of the capacity control valve, and is discharged to the outside from the compressor Capacity control means for bringing the fluid discharge amount close to the required value required for the compressor;
A temperature actuator that mechanically operates in response to the temperature of the refrigerant in the discharge chamber, and an overheat prevention means for increasing the pressure in the crank chamber when the temperature of the working fluid in the discharge chamber approaches an upper limit temperature. A variable capacity reciprocating compressor characterized by comprising:   2. The variable capacity reciprocating compressor according to claim 1, wherein the temperature actuator includes a heat-sensitive material whose volume or shape changes with a change in temperature of the working fluid.   The variable capacity reciprocating compressor according to claim 2, wherein the heat sensitive material is a wax.   The variable capacity reciprocating compressor according to claim 2, wherein the temperature actuator has a bellows that expands and contracts with a change in volume of the heat sensitive material.   The variable capacity reciprocating compressor according to claim 2, wherein the heat sensitive material is a bimetal.

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