JP2000265948A - Variable capacity compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent differential pressure between a crank chamber and a cylinder bore from being excessively increased. SOLUTION: A suction passage 90 connects a suction chamber 37 of a compressor to a piping on an evaporator 74 side of an external refrigerant circuit 71. A check valve 92 is arranged on the suction passage 90 to open and close the suction passage 90 on the basis of differential pressure between the suction chamber 37 side and the evaporator 74 side of the external refrigerant circuit 71. The check valve 92 closes the suction passage 90 when pressure on the suction chamber 37 side exceeds pressure on the evaporator 74 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement compressor which is used, for example, in a vehicle air conditioner to compress a refrigerant gas and change a discharge capacity.

[0002]

2. Description of the Related Art As this type of variable displacement compressor (hereinafter simply referred to as a compressor), for example, there is one as shown in FIG. That is, the housing 101 has a crankcase
102 is formed, and the drive shaft 103 is rotatably held. The lip seal 104 is interposed between the lip seal 104 and the housing 101 to seal the drive shaft 103.

[0003] The drive shaft 103 is an electromagnetic friction clutch.
It is operatively connected via 105 to a vehicle engine Eg as an external drive source. The friction clutch 105 includes a rotor 106 operatively connected to the vehicle engine Eg, an armature 107 fixed to the drive shaft 103 so as to be integrally rotatable, and an electromagnetic coil 10.
8 and The electromagnetic coil 108 attracts the armature 107 to the rotor 106 side by excitation, and
Is made possible to transmit power between the vehicle engine Eg and the drive shaft 103 (the friction clutch 105 is turned on). When the electromagnetic coil 108 is demagnetized in this state, the armature 107 is separated from the rotor 106, and the power transmission between the vehicle engine Eg and the drive shaft 103 is cut off (the friction clutch 105 is turned off).

The rotating support 109 is fixed to the drive shaft 103 in the crank chamber 102, and the rotating support 109 is
Is connected to a swash plate 110 via a hinge mechanism 111. The swash plate 110 is connected to the rotation support 109 via a hinge mechanism 111 so that the swash plate 110 can rotate integrally with the drive shaft 103 and can change the inclination angle of the drive shaft 103 with respect to the axis L. The minimum inclination angle defining section 112 is provided on the drive shaft 103,
The minimum inclination angle of the swash plate 110 is specified.

[0005] Cylinder bore 113, suction chamber 114 and discharge chamber
115 is formed in the housing 101. Piston 116
Are reciprocally accommodated in a cylinder bore 113 and connected to a swash plate 110. The valve / port forming body 117 provided in the housing 101 includes a cylinder bore 113 and a suction chamber 114 adjacent to each other, and a cylinder bore 113 and a discharge chamber 11 adjacent to each other.
4 and are divided respectively.

Then, the rotational movement of the drive shaft 103 is converted into a reciprocating movement of a piston 116 via a rotary support 109, a hinge mechanism 111 and a swash plate 110, and the suction port 117a of the valve / port forming body 117 and the suction valve are formed. Suction of the refrigerant gas from the suction chamber 114 into the cylinder bore 113 via the 117b, compression of the suction refrigerant gas, and discharge chamber of the compressed refrigerant gas via the discharge port 117c and the discharge valve 117d of the valve / port forming body 117. 115
The compression cycle of discharge to is repeated.

The drive shaft biasing spring 118 is interposed between the housing 101 and the drive shaft 103. Drive shaft biasing spring 118
Urges the drive shaft 103 toward the front of the axis L (to the left in the drawing) to absorb the manufacturing tolerance of each component at the time of assembling and suppress the play in the longitudinal direction of the axis L.

The bleed passage 119 is provided between the crank chamber 102 and the suction chamber 11.
4 and communicate. The air supply passage 120 communicates the discharge chamber 115 with the crank chamber 102. The capacity control valve 121 is formed of an electromagnetic valve, and is capable of adjusting the opening of the air supply passage 120. Capacity control valve
121 is the cabin temperature, cabin set temperature, friction clutch 10
5 is turned off or the vehicle engine Eg is stopped.

When the displacement control valve 121 adjusts the opening of the air supply passage 120, the amount of high-pressure discharge refrigerant gas introduced into the crank chamber 102 is adjusted.
From the relationship with the amount of refrigerant gas released to 114, the crankcase 1
02 pressure is changed. Accordingly, the difference between the pressure in the crank chamber 102 and the pressure in the cylinder bore 113 via the piston 116 is changed, and the inclination angle of the swash plate 110 is changed. As a result, the stroke amount of the piston 116 is changed, and the discharge capacity is adjusted.

In particular, the displacement control valve 121 fully opens the air supply passage 120 when the friction clutch 105 is turned off or the vehicle engine Eg is stopped. Therefore, the crankcase 10
2, the difference between the pressure of the cylinder bore 113 and the pressure of the cylinder bore 113 via the piston 116 increases, and the inclination angle of the swash plate 110 decreases. As a result, the compressor stops operating with the inclination angle of the swash plate 110 being minimized, so that the next startup is from the minimum discharge capacity state where the load torque is the smallest, and the shock generated at the startup is reduced.

[0011]

However, in the above prior art, for example, when the temperature of the passenger compartment is much higher than the set temperature, that is, when the demand for cooling the passenger compartment is high, the capacity control valve 121 is not used. As a result, the air supply passage 120 is completely closed,
The displacement of the compressor is adjusted to a maximum.

Here, it is assumed that the friction clutch 105 is turned off or the vehicle engine Eg is stopped and the compressor is stopped from the state where the compressor is operated at the maximum discharge capacity. In such a case, the displacement control valve 121 suddenly and fully opens the air supply passage 120 in the fully closed state in order to minimize the discharge displacement. Accordingly, the high-pressure refrigerant gas in the discharge chamber 115 is rapidly supplied to the crank chamber 102, and the bleed passage 119 cannot fully escape the rapid inflow of the refrigerant gas, so that the pressure in the crank chamber 102 rises excessively. Also, the pressure in the cylinder bore 113 is reduced by trying to equalize the pressure in the suction chamber 114 with a low pressure due to the stoppage of the compressor. As a result, the pressure difference between the cylinder bore 113 and the crank chamber 102 is excessively increased.

For this reason, the swash plate 110 in which the inclination angle is minimized.
(Shown by a two-dot chain line in FIG. 9) is a minimum inclination angle defining portion.
The rotating support 109 is strongly pushed rearward (rightward in the drawing) through the hinge mechanism 111. As a result, the driving shaft 103 receives a strong moving force toward the rear side of the axis L, and slides against the urging force of the driving shaft urging spring 118. For this reason, the following problem may occur.

(1) When the drive shaft 103 slides in the direction of the axis L, the sliding position with the lip seal 104 may deviate from a predetermined position called a contact line. Foreign matter such as sludge often adheres to portions of the outer peripheral surface of the drive shaft 103 that deviate from the contact lines. For this reason, the lip seal 104 is
3 Sludge is caught in between and the shaft sealing performance decreases,
Problems such as gas leaks.

(2) When the friction clutch 105 is turned off, in other words, when the power transmission between the vehicle engine Eg and the drive shaft 103 is cut off, the drive shaft 103
When it slides rearward, the armature 107 fixed to the drive shaft 103 moves to the rotor 106 side. Rotor 106 and armature 107 when friction clutch 105 is off
Is set to a very small value (for example, 0.5 mm). Therefore, the sliding movement of the driving shaft 103 to the rear side of the axis L causes the rotor 106 and the armature to move.
The problem is that the clearance between the armature 107 and the armature 107 easily disappears, and the armature 107 slides on the rotor 106 in a rotating state to generate abnormal noise and vibration, and also allows power transmission.

(3) When the drive shaft 103 slides rearward on the axis L, the piston 116 connected to the drive shaft 102 via the swash plate 110 slides rearward in the cylinder bore 113, The dead point is the valve / port forming body 11
Try to shift to the 7 side. The compressor is a friction clutch
Immediately after the 105 is turned off or the vehicle engine Eg stops,
It keeps turning a bit due to its inertia. Accordingly, during the inertial rotation, when the piston 116 is located at the top dead center, the piston 116 impacts against the valve / port forming body 117, and vibrations and noises are generated due to the collision. Or a problem such as breakage of the valve / port forming body 117.

In order to prevent the slide movement of the drive shaft 103, a measure to increase the urging force of the drive shaft urging spring 118 can be considered. However, the durability of the thrust bearing 122 which receives this large load is considered. A new problem of reduction and increase in power loss occurs.

The present invention has been made in view of the problems existing in the prior art described above, and an object of the present invention is to provide a variable valve which can prevent an excessive increase in a pressure difference between a crank chamber and a cylinder bore. An object of the present invention is to provide a displacement compressor.

[0019]

According to the first aspect of the present invention, there is provided a variable displacement compressor which is applied to a refrigeration circuit and compresses a refrigerant gas. A cylinder bore and a suction chamber are formed, and a drive shaft is rotatably held so as to pass through the crank chamber. In the crank chamber, a cam plate is connected to the drive shaft so as to be integrally rotatable and change an inclination angle. A piston connected to a cam plate is reciprocally housed in the cylinder bore, and a valve / port forming body having a suction port, a suction valve, a discharge port, and a discharge valve is housed in the housing. The piston is mounted between the housing and the drive shaft in a direction away from the valve / port formation body. A drive shaft biasing member for biasing the shaft along the axis is interposed, the crank chamber and the discharge pressure region are communicated via an air supply passage, and the crank chamber and the suction chamber are constantly connected via a bleed passage. A capacity control valve that is communicated with and controls the opening of at least one of the air supply passage or the bleed passage controlled by an external signal to change the pressure of the crank chamber, and that the pressure of the crank chamber and the pressure of the cylinder bore are changed. In the variable displacement compressor having a configuration in which the displacement angle is adjusted by changing the inclination angle of the cam plate in accordance with the difference via the piston, a refrigerant flow path between the suction chamber and the evaporator of the external refrigerant circuit is provided. A check valve that opens or closes the refrigerant flow path according to a pressure difference between before and after the check valve is disposed, and the check valve closes the refrigerant flow path when the pressure on the suction chamber side becomes equal to or higher than the pressure on the evaporator side. Is characterized by To.

In this configuration, the displacement control valve is controlled by an external signal to regulate the pressure in the crank chamber and regulate the displacement of the compressor. Therefore, when the compressor is stopped, it is possible to reduce the load torque by positively minimizing the discharge capacity to reduce the shock generated at the next start. In this case, when the compressor is stopped from a state in which the compressor is operated at the maximum discharge capacity, the pressure in the crank chamber is rapidly increased to minimize the discharge capacity, and tends to increase excessively.

However, when the operation of the compressor is stopped, the circulation of the refrigerant between the compressor and the external refrigerant circuit is stopped. The bleed passage always connects the crank chamber and the suction chamber, and the refrigerant gas in the crank chamber is supplied to the suction chamber. Therefore, the pressure on the suction chamber side in the refrigerant flow path becomes equal to or higher than the pressure on the evaporator side, and the check valve closes the refrigerant flow path. That is, the suction chamber side in the refrigerant flow path is shut off from the evaporator side, and the small volume on the suction chamber side is quickly increased in pressure by the flow of the refrigerant gas from the crank chamber through the bleed passage. As a result, the pressure in the cylinder bore, which attempts to equalize the pressure in the suction chamber, can be maintained high, and the difference between the pressure in the crank chamber and the pressure in the crank chamber does not increase excessively. The phenomenon of sliding in the axial direction does not occur.

According to the second aspect of the present invention, an electromagnetic friction clutch capable of interrupting power transmission is disposed between the drive shaft and an external drive source that rotationally drives the drive shaft. A rotor rotatably supported by the housing and operatively connected to an external drive source, an armature fixed to the drive shaft so as to be integrally rotatable and disposed opposite to the rotor, and the armature is attracted to the rotor by excitation. An electromagnetic coil that couples the two and enables power transmission is provided.

In this configuration, when the friction clutch is turned off, the displacement control valve positively minimizes the discharge capacity to reduce the load torque of the compressor, thereby alleviating the shock that occurs when the friction clutch is next turned on. Can be set. Also in this case, when the friction clutch is turned off from the state where the compressor is operating at the maximum discharge capacity,
In order to minimize the discharge capacity, the pressure in the crank chamber is rapidly increased and tends to increase excessively. However, in such a case as well, the check valve closes the refrigerant flow path in the same manner as in the first aspect of the invention, thereby preventing the difference between the pressure in the cylinder bore and the pressure in the crank chamber from being excessively increased. In other words, by providing a friction clutch between the external drive source and the external drive source, a problem that the pressure in the crank chamber excessively rises easily even when the friction clutch is off, in addition to when the external drive source is stopped, is likely to occur. The effect of providing the valve is more effectively achieved.

According to a third aspect of the present invention, the displacement control valve is configured to adjust at least the opening of the air supply passage. In this configuration, a high discharge pressure is used for controlling the pressure in the crank chamber.
The crank chamber can be quickly pressurized as compared with a case where the displacement control valve opens and closes only the bleed passage to adjust the discharge capacity, that is, a case where a pressure lower than the discharge pressure is handled. Therefore, when the compressor is stopped, the discharge capacity can be quickly minimized, and the next start-up of the compressor immediately after the stop can be started from the minimum discharge capacity. From another point of view, compared with the case where the displacement control valve opens and closes only the bleed passage to adjust the discharge displacement, the problem that the pressure in the crank chamber rises excessively easily occurs. Is more effectively achieved.

According to a fourth aspect of the present invention, the displacement control valve is
A valve body that opens and closes one of an air supply passage or a bleed passage, and a pressure-sensitive member that is operatively connected to the valve body and that operates the valve body in a suction pressure region in accordance with a pressure on the suction chamber side of the open / close position of the check valve in the suction pressure region. And a set suction pressure changing means for changing a set suction pressure serving as a reference for the operation of the pressure-sensitive member by being controlled by an external signal.

In this configuration, when the pressure on the suction chamber side increases due to the closing of the check valve when the compressor is stopped, the pressure-sensitive member also operates the valve body in response to the increase in pressure. That is, when the pressure in the suction chamber increases, the pressure-sensitive member operates the valve body in a direction to decrease the pressure in the crank chamber. Therefore, the pressure in the crank chamber does not excessively increase, and the pressure in the cylinder bore is maintained high, and the excessive increase in the differential pressure between the two can be effectively prevented.

According to a fifth aspect of the present invention, the check valve is provided in a housing. In this configuration, for example, when the check valve is disposed on the pipe of the external refrigerant circuit, the configuration of the existing pipe must be changed. However, by disposing the check valve in the housing of the compressor, it is possible to use the existing piping of the external refrigerant circuit as it is. That is, the present invention can be applied to the refrigeration circuit only by changing the structure of the compressor.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention embodied in a variable displacement compressor used in a vehicle air conditioner will be described.

As shown in FIG. 1, the front housing 1
1 is a cylinder block 12 as a center housing
And is fixedly joined to the front end of the. Rear housing 13
Is fixedly connected to the rear end of the cylinder block 12 via a valve / port forming body 14. The front housing 11, the cylinder block 12, and the rear housing 13 constitute a compressor housing. In addition,
The left side of FIG. 1 is the front of the compressor, and the right side is the rear.

The valve / port forming body 14 has a suction valve forming plate 14b on the front side of the port forming plate 14a, a discharge valve forming plate 14c on the rear side, and a retainer forming plate 14d on the rear side of the discharge valve forming plate 14c. Are respectively polymerized.

The crank chamber 15 is provided in the front housing 1.
1 and a cylinder block 12. The drive shaft 16 is disposed so as to pass through the crank chamber 15, and is rotatably supported between the front housing 11 and the cylinder block 12.

The front end of the drive shaft 16 is supported by the front housing 11 via a radial bearing 17. The accommodation hole 12a is provided through the center of the cylinder block 12. The rear end side of the drive shaft 16 has an accommodation hole 12a.
And is supported via a radial bearing 18. The spring seat 21 is made of a circlip,
2a is fitted and fixed to the inner peripheral surface (cylinder block 12). The thrust bearing 19 and the drive shaft biasing spring 20 as a drive shaft biasing member are interposed between the rear end face of the drive shaft 16 and the spring seat 21 in the accommodation hole 12a. The drive shaft biasing spring 20 is a coil spring, and biases the drive shaft 16 toward the front of the axis L. The transmission of the rotational force of the drive shaft 16 to the drive shaft biasing spring 20 is interrupted by the interposition of the thrust bearing 19.

The front end of the drive shaft 16 projects through the front wall of the front housing 11 to the outside. A lip seal 22 is used as a shaft sealing device for the drive shaft 16, and the lip seal 22 is interposed between the front end of the drive shaft 16 and the front housing 11. The lip seal 22 is connected to the drive shaft 16 by a lip ring 22a.
The drive shaft 16 is sealed by pressing against the outer peripheral surface of the drive shaft 16.

The electromagnetic friction clutch 23 is interposed between the vehicle engine Eg as an external drive source and the drive shaft 16. That is, the rotor 24 of the friction clutch 23
Is rotatably supported on the outer wall surface of the front housing 11 via an angular bearing 25. A belt 26 from the vehicle engine Eg is wound around the outer periphery of the rotor 24. The hub 27 is fixed to the front end of the drive shaft 16 and elastically supports the armature 28 on the outer peripheral side. The armature 28 includes a drive shaft biasing spring 20.
And opposite to the rotor 24. The electromagnetic coil 29 is supported on the outer wall surface of the front housing 11 and is arranged in the rotor 24.

When the electromagnetic coil 29 is energized by energization while the vehicle engine Eg is activated, an attractive force based on an electromagnetic force is applied between the armature 28 and the rotor 24. Accordingly, the armature 28 moves against the elastic force of the hub 27 and presses against the rotor 24, so that the friction clutch 23 is turned on. In this ON state, the driving force of the vehicle engine Eg is applied to the belt 26 and the friction clutch 23.
To the drive shaft 16 (FIG. 1). When the electromagnetic coil 29 is demagnetized from this state, the armature 28 is separated from the rotor 24 by the elastic force of the hub 27, and the friction clutch 23 is turned off. In this off state, transmission of the driving force from the vehicle engine Eg to the drive shaft 16 is interrupted (FIG. 5).

The rotary support 30 is fixed to the drive shaft 16 in the crank chamber 15. The swash plate 31 as a cam plate can be tilted to the drive shaft 16 and
6 is slidably supported in the direction of the axis L.
The hinge mechanism 32 is interposed between the rotation support 30 and the swash plate 31. The swash plate 31 can rotate integrally with the drive shaft 16 and can change the inclination angle with respect to the axis L by hinge connection to the rotation support 30 via a hinge mechanism 32.

The minimum tilt angle defining section 34 is disposed between the swash plate 31 and the cylinder block 12 on the drive shaft 16. The minimum tilt angle defining portion 34 is formed by externally fixing a ring-shaped member to the outer peripheral surface of the drive shaft 16. As shown by a two-dot chain line in FIG. 1, the minimum inclination angle of the swash plate 31 is defined by contact with the minimum inclination angle defining part 34. As shown by the solid line in FIG. 1, the maximum inclination angle of the swash plate 31 is defined by the contact with the rotating support 30.

As shown in FIGS. 1 and 4, a plurality of (six) cylinder bores 33 are formed at predetermined intervals on the same circumference around the axis L of the drive shaft 16 in the cylinder block 12. A single-headed piston 35 is housed in each cylinder bore 33. Each cylinder bore 33
The front and rear are closed by the front end face of the piston 35 and the front face of the valve / port forming body 14. Each piston 35 is moored to the outer peripheral portion of the swash plate 31 via a shoe 36. The rotation of the drive shaft 16 is performed via the rotation support 30, the hinge mechanism 32, the swash plate 31, and the shoe 36.
The reciprocating motion of the piston 35 in the cylinder bore 33 is converted.

As shown in FIGS. 1 and 2, a suction chamber 37 as a suction pressure area is formed in a central portion of the rear housing 13. Discharge chamber 38 as discharge pressure area
Are defined on the outer peripheral side of the suction chamber 37 in the rear housing 13. The suction chamber 37 and the discharge chamber 38 are respectively connected to the cylinder bore 33 through the valve / port formation body 14.
It is adjacent to. Intake port 39 and discharge port 40
Is formed on the port forming plate 14 a of the valve / port forming body 14 so as to correspond to the cylinder bore 33. The suction valve 41 is connected to the suction port 39 on the suction valve forming plate 14b.
It is formed corresponding to. The discharge valve 42 is formed corresponding to the discharge port 40 on the discharge valve forming plate 14c. The retainer 43 is formed on the retainer forming plate 14d so as to correspond to the discharge valve 42. The retainer 43 regulates the maximum opening of the discharge valve 42.

Then, the refrigerant gas in the suction chamber 37 is sucked into the cylinder bore 33 through the suction port 39 and the suction valve 41 by moving from the top dead center side to the bottom dead center side of the piston 35. The refrigerant gas sucked into the cylinder bore 33 is
The piston 35 is compressed to a predetermined pressure by moving from the bottom dead center side to the top dead center side.
The liquid is discharged to the discharge chamber 38 through the discharge chamber 2.

The air supply passage 44 is provided between the discharge chamber 38 and the crank chamber 1.
5 is communicated. The bleed passage 45 always connects the crank chamber 15 and the suction chamber 37. The capacity control valve 46 is interposed on the air supply passage 44. Then, the capacity control valve 46 adjusts the opening degree of the air supply passage 44, so that the amount of the high-pressure discharge refrigerant gas introduced into the crank chamber 15 is adjusted, and the refrigerant gas is introduced into the refrigerant gas suction chamber 37 through the bleed passage 45. From the amount of escape
The pressure in the crank chamber 15 is changed. Therefore, the piston 3 between the pressure in the crank chamber 15 and the pressure in the cylinder bore 33
5 is changed, and the inclination angle of the swash plate 31 is changed. As a result, the stroke amount of the piston 35 is changed, and the discharge capacity is adjusted.

Next, the capacity control valve 46 will be described in detail. As shown in FIG. 3, the valve chamber 51 is defined on the air supply passage 44. The valve body 52 is housed in the valve chamber 51. The valve hole 53 is opened in the valve chamber 51 so as to face the valve body 52. The forcible opening spring 54 is connected to the valve chamber 51.
And urges the valve body 52 in a direction to open the valve hole 53. The valve chamber 51 and the valve hole 53 constitute a part of the air supply passage 44.

The pressure sensing chamber 55 is formed adjacent to the valve chamber 51. The pressure sensing chamber 55 is always in communication with the suction chamber 37 via the pressure detection passage 47. The bellows 56 as a pressure-sensitive member is housed in the pressure-sensitive chamber 55. Setting spring 5
7 is arranged in the bellows 56. Setting spring 57
Is for setting the initial length of the bellows 56. The pressure sensing rod 58 is formed integrally with the valve body 52 and operatively connects the bellows 56 and the valve body 52.

The plunger chamber 59 is adjacent to the valve chamber 51 on the side opposite to the pressure-sensitive chamber 55, and a fixed iron core 60 is fitted in an upper opening thereof so as to be separated from the valve chamber 51. The movable iron core 61 is housed in the plunger chamber 59. The follower spring 62 is housed in the plunger chamber 59 and urges the movable iron core 61 toward the valve body 52. The solenoid rod 63 is formed integrally with the valve body 74. An end on the movable iron core 61 side of the solenoid rod 63 is
And, the urging force of the follower spring 62 makes contact with the movable iron core 61. Therefore, the valve element 52 and the movable iron core 61 are operatively connected via the solenoid rod 63. The electromagnetic coil 64 is disposed outside the fixed core 60 and the movable core 61 so as to straddle the two cores 60, 61. The fixed iron core 60, the movable iron core 61, the electromagnetic coil 64, and the solenoid rod 63 form an electromagnetic configuration of the capacity control valve 46, and constitute a set suction pressure changing means.

As shown in FIG. 1, in the variable displacement compressor having the above-described structure (hereinafter simply referred to as a compressor), the suction chamber 37 and the discharge chamber 38 are connected by an external refrigerant circuit 71. . The external refrigerant circuit 71 includes a condenser 72, an expansion valve 73, and an evaporator 74. The external refrigerant circuit 71 and the compressor constitute a refrigeration circuit of the vehicle air conditioner.

An air conditioner switch 80 which is a main switch of the vehicle air conditioner, a cabin temperature sensor 81 for detecting the temperature in the cabin of the vehicle, and a cabin temperature setting device 82 for the occupant to set the temperature in the cabin. Are respectively connected to the control computer C. The control computer C controls each of the electromagnetic coils 2 of the friction clutch 23 and the capacity control valve 46.
9, 64 and a power source S such as a vehicle battery. The control computer C sends a signal from the power source S to each of the electromagnetic coils 29 based on external signals such as the ON / OFF of the air conditioner switch 80, the vehicle temperature from the vehicle temperature sensor 81, and the set temperature from the vehicle temperature setting device 82 ,
64 is controlled.

Generally, when the operation of the vehicle engine Eg is stopped (specifically, when an ignition key (not shown) is operated to the accessory off position), most of the power supply to the electric components of the vehicle is performed. And this is no exception for vehicle air conditioners. Therefore, when the operation of the vehicle engine Eg is stopped, the power supply line between each of the electromagnetic coils 29 and 64 and the power supply S is cut off on the upstream side of the control computer C, and the power supply S is disconnected from each of the electromagnetic coils 29 and 6.
Power supply to 4 is stopped.

Next, the operation of the capacity control valve 46 will be described. When the temperature detected by the cabin temperature sensor 81 becomes equal to or higher than the set temperature of the cabin temperature setter 82 under the ON condition of the air conditioner switch 80 in the operating state of the vehicle engine Eg, the control computer C sends an electromagnetic signal A current is input to the coil 29. Therefore, the friction clutch 23
Is turned on to start the compressor.

In this state, the bellows 56 of the capacity control valve 46
Tries to expand and contract in response to the suction pressure of the pressure-sensitive chamber 55, and the expansion and contraction of the bellows 56 applies a load to the valve body 52 via the pressure-sensitive rod 58 in a direction to open or close the valve hole 53. You. Further, the control computer C determines an input current value to the electromagnetic coil 64 of the capacity control valve 46 based on the compartment temperature from the compartment temperature sensor 81 and the set temperature from the compartment temperature setting device 82. Control computer C
Causes the current of the determined value to be input from the power supply S to the electromagnetic coil 64. When a current is input to the electromagnetic coil 64, an attractive force (electromagnetic force) corresponding to the input current value is generated between the fixed iron core 60 and the movable iron core 61. This suction force is applied to the valve hole 53.
Is applied to the valve body 52 as a load in a direction to decrease the opening of the valve body 52.

As described above, the degree of opening of the valve hole 53 by the valve element 52 depends on the load applied by the expansion and contraction of the bellows 56, the load applied by the attraction force between the fixed iron core 60 and the movable iron core 61, and It is determined by the total force such as the load applied by the urging forces of the springs 54 and 62.

For example, the control computer C increases the input current value to the electromagnetic coil 64 of the capacity control valve 46 as the difference between the cabin temperature and the set temperature increases, that is, as the demand for cooling the cabin increases. . Accordingly, the suction force between the fixed iron core 60 and the movable iron core 61 is increased, and the load in the direction of decreasing the opening of the valve hole 53 applied to the valve body 52 is increased. Accordingly, the capacity control valve 46 sets the target suction pressure (set suction pressure) low, and operates the valve body 52 by the bellows 56 to open and close the valve hole 53 so as to maintain the set suction pressure. That is, the capacity control valve 46
By increasing the input current value to the electromagnetic coil 64, the displacement of the compressor is adjusted so as to maintain a lower suction pressure.

When the opening degree of the valve hole 53 (the air supply passage 44) is reduced, the flow rate of the refrigerant gas supplied from the discharge chamber 38 to the crank chamber 15 is reduced. When the amount of the refrigerant gas supplied to the crank chamber 15 decreases, the pressure of the crank chamber 15 gradually decreases due to the escape of the refrigerant gas to the suction chamber 37 through the bleed passage 45. Therefore, the difference between the pressure in the crank chamber 15 and the pressure in the cylinder bore 33 via the piston 35 is reduced, and the inclination angle of the swash plate 31 is increased. As a result, the stroke amount of the piston 35 increases, and the displacement of the compressor increases.

Conversely, the control computer C reduces the input current value to the electromagnetic coil 64 of the capacity control valve 46 as the difference between the cabin temperature and the set temperature is smaller, that is, as the cooling demand for the cabin is lower. I do. For this reason, the attraction force between the fixed iron core 60 and the movable iron core 61 is weakened, and the load in the direction of decreasing the opening of the valve hole 53 applied to the valve body 52 is reduced. Accordingly, the capacity control valve 46 sets the set suction pressure high, and operates the valve body 52 by the bellows 56 to maintain the set suction pressure, thereby opening and closing the valve hole 53. That is, the displacement control valve 46 adjusts the discharge displacement of the compressor so as to maintain a higher suction pressure by reducing the input current value to the electromagnetic coil 64.

When the degree of opening of the valve hole 53 (the air supply passage 44) increases, the flow rate of the refrigerant gas supplied from the discharge chamber 38 to the crank chamber 15 increases. When the amount of the refrigerant gas supplied to the crank chamber 15 increases, the pressure in the crank chamber 15 gradually increases because the bleed passage 45 cannot escape the increased amount. Therefore, the difference between the pressure in the crank chamber 15 and the pressure in the cylinder bore 33 via the piston 35 increases. As a result, the inclination angle of the swash plate 31 is reduced, the stroke amount of the piston 35 is reduced, and the displacement of the compressor is reduced.

Next, a characteristic configuration of the present embodiment will be described. As shown in FIG. 1 and FIG.
And a pipe 71a of the external refrigerant circuit 71 on the side of the evaporator 74,
It communicates via a suction passage 90 provided in the rear housing 13. The pipe 71a and the suction passage 90 constitute a refrigerant passage. The accommodation room 91 includes the rear housing 13.
Is formed such that the diameter from the middle of the suction passage 90 to the suction chamber 37 is enlarged. Therefore, this accommodation room 9
1, the external refrigerant circuit 71 in the suction passage 90.
The positioning step 91a is formed by the difference in diameter from the side part.

The check valve 92 includes a valve seat 93 having a valve hole 93a, a valve body 94 which opens and closes the valve hole 93a by being brought into and out of contact with the valve seat 93, in a case 96 having a closed bottom cylindrical shape. An urging spring 9 for urging the valve element 94 in a direction to close the hole 93a.
5 is provided. The check valve 92 is press-fitted into the accommodation chamber 91 to a position where the tip of the case 96 contacts the positioning step 91a. The check valve 92 press-fitted and fixed in the housing chamber 91 has an inner space of a case 96 for housing the valve body 94.
A plurality of communication holes 96a communicated with the suction passage 90 through the valve holes 93a and penetrated through the peripheral surface of the case 96.
Through the suction chamber 37. That is, in the check valve 92, the valve hole 93a, the inner space of the case 96, and the communication hole 96a constitute a part of the suction passage 90. The pressure guiding hole 96b connects the inner space of the case 96 to the suction chamber 37 on the opposite side to the valve hole 93a, and introduces the pressure of the suction chamber 37 as a back pressure acting on the valve element 94.

The valve element 94 of the check valve 92 acts as a load acting on the basis of the pressure difference between the front and rear sides, that is, a pressure acting on the front end face of the external refrigerant circuit 71 and a back pressure. Load based on the difference between the pressure of the suction chamber 37 and
The valve spring 93 is brought into and out of contact with the valve seat 93 by the combined force with the load based on the urging force of the urging spring 95, and the valve hole 93a (suction passage 90)
Is opened or closed. The check valve 92 is provided when the compressor is in an operating state and the refrigerant is circulating between the external refrigerant circuit 71 and the compressor, that is, the pressure on the evaporator 74 side is higher than the pressure on the suction chamber 37 side. If so, the suction passage 90
Is released (FIG. 2). The check valve 92 is connected to the suction chamber 37.
When the pressure on the side becomes equal to or higher than the pressure on the evaporator 74 side, the suction passage 9
0 is closed, and the backflow of the refrigerant gas from the suction chamber 37 side to the evaporator 74 side is prevented (FIG. 6).

Next, the characteristic operation of this embodiment will be described. While the compressor is running, turn on the air conditioner switch 8
When 0 is turned off or when the vehicle interior temperature becomes lower than the set temperature, the control computer C stops the power supply to the electromagnetic coil 29 to turn off the friction clutch 23, and the electromagnetic coil 64 of the displacement control valve 46. Stop supplying power to Further, when the vehicle engine Eg is stopped in the operating state of the compressor, the power supply line from the power supply S to each of the electromagnetic coils 29 and 64 is shut off on the upstream side of the control computer C.

As described above, when the power supply to the electromagnetic coil 64 of the capacity control valve 46 is stopped by turning off the friction clutch 23 or stopping the vehicle engine Eg, the attractive force between the fixed iron core 60 and the movable iron core 61 is reduced. Disappears and the set suction pressure is set to the highest value (when the vehicle engine Eg is stopped,
The same state as when the set suction pressure is set to the highest value,
Is preferred). Accordingly, the displacement control valve 46 fully opens the air supply passage 44, and the compressor minimizes the inclination angle of the swash plate 31. As a result, the next start of the compressor is from the minimum discharge capacity state where the load torque is the smallest, and the shock generated at the start is reduced.

Now, as shown in the graph of FIG.
When the above-described stop of the compressor is performed from the operating state at the maximum discharge capacity, the capacity control valve 46 suddenly and fully opens the air supply passage 44 in the fully closed state. Therefore, the discharge chamber 3
8 is rapidly supplied to the crank chamber 15 and the bleed passage 45 does not allow the rapid inflow of the refrigerant gas to escape, so that the pressure in the crank chamber 15 rapidly increases.

However, when the compressor is stopped, the circulation of the refrigerant with the external refrigerant circuit 71 is also stopped, and the refrigerant gas in the crank chamber 15 is supplied to the suction chamber 37 via the bleed passage 45 which is always in communication. Because of the inflow, the suction passage 9
At 0, the pressure on the suction chamber 37 side becomes equal to or higher than the pressure on the evaporator 74 side. Accordingly, the check valve 92 closes the suction passage 90, and the backflow of the refrigerant gas from the suction chamber 37 to the evaporator 74 is prevented. As a result, the pressure of the suction chamber 37 is quickly increased by the supply of the refrigerant gas from the crank chamber 15. Therefore, the pressure of the cylinder bore 33 is maintained at a high level in an attempt to equalize the pressure of the suction chamber 37 with a high pressure due to leakage of the refrigerant gas from the seal portion of the suction valve 41.

The cylinder bore 33 shown in the above graph
Indicates an average value of the plurality of cylinder bores 33. Further, in the graph, the pressure of the cylinder bore 33 is rapidly increased immediately after the compressor is stopped. This is because part of the piston 35 moves toward the top dead center in the process of decreasing the inclination angle of the swash plate 31. This is because the refrigerant gas remaining in the cylinder bore 33 is compressed.

In addition, due to the above-described increase in the pressure of the suction chamber 37, the pressure of the pressure-sensitive chamber 55 that is always in communication with the suction chamber 37 via the pressure detection passage 47 is increased from the set suction pressure. . Therefore, the capacity control valve 46 reduces the opening degree of the valve hole 53 in the fully open state, and reduces the supply amount of the high-pressure refrigerant gas from the discharge chamber 38 to the crank chamber 15. As a result, a sudden increase in the pressure in the crank chamber 15 is reduced on the way, and an excessive increase in the pressure in the crank chamber 15 is prevented.

As described above, excessive expansion of the differential pressure between the crank chamber 15 and the cylinder bore 33 is prevented, and the swash plate 31 having the minimum inclination angle is pressed against the minimum inclination angle defining portion 34 with excessive force. Also, the rotation support 30 is not strongly pulled through the hinge mechanism 32. Therefore, the drive shaft 16 does not slide toward the rear of the axis L against the biasing force of the drive shaft biasing spring 20.

Here, the graph of FIG. 7B shows a graph of a comparative example in which the check valve 92 is omitted from the compressor of the present embodiment. In this comparative example, even if the refrigerant gas is supplied from the crank chamber 15 to the suction chamber 37 when the compressor is stopped, the evaporator 7
Backflow of the refrigerant gas to the side 4 is allowed, and the suction chamber 37
Pressure hardly rises. That is, the volume of the refrigerant gas from the crank chamber 15 that must be increased is too large. Therefore, the pressure in the cylinder bore 33 is greatly reduced in an attempt to equalize the pressure in the suction chamber 37 with a low pressure.

Since the pressure in the suction chamber 37 hardly rises, the pressure in the pressure sensing chamber 55 does not rise above the set suction pressure, and the capacity control valve 46 maintains the state in which the valve hole 53 is fully opened. Will do. Therefore, the crank chamber 15
, The pressure in the crank chamber 15 increases excessively.

Accordingly, in this comparative example, the difference between the pressure in the crank chamber 15 and the pressure in the cylinder bore 33 is excessively enlarged, and the drive shaft 16 is moved against the axis of the drive shaft 16 against the biasing force of the drive shaft biasing spring 20. L slides backward.

The present embodiment having the above configuration has the following effects. (1) Since the check valve 92 is provided on the suction passage 90, the pressure in the cylinder bore 33 can be maintained high even after the compressor is stopped, so that an excessive increase in the difference from the pressure in the crank chamber 15 is prevented. We were able to. Therefore, the drive shaft 16
However, it is possible to prevent the sliding movement toward the rear side of the axis L against the urging force of the driving shaft urging spring 20, and therefore, the following effects are obtained.

(1-1) The relative sliding movement between the lip seal 22 and the drive shaft 16 can be prevented. Therefore,
The sliding position between the lip ring 22a of the lip seal 22 and the drive shaft 16 does not largely deviate from a predetermined contact line on the drive shaft 16. For this reason, it is possible to prevent foreign matter, such as sludge, attached to portions other than the contact line from being caught between the sliding contact surfaces of the lip ring 22a and the drive shaft 16. Therefore, lip seal 2
2 is prevented from deteriorating at an early stage or causing gas leakage, which leads to improvement in the durability of the compressor.

(1-2) The armature 28 of the friction clutch 23 is moved toward and away from the rotor 24 in the longitudinal direction of the axis L. Therefore, if the drive shaft 16 slides rearward on the axis L in the off state of the friction clutch 23,
Although no suction force is generated between the rotor 24 and the armature 28, a situation may occur in which a predetermined clearance (FIG. 5) cannot be secured between the rotor 24 and the armature 28. However, as described above, the sliding movement of the drive shaft 16 to the rear side of the axis L is prevented, a predetermined clearance can be secured between the rotor 24 and the armature 28, and the friction clutch 23 is turned off. There is no possibility that both 24 and 28 remain in contact. Therefore, no sliding occurs between the rotor 24 and the armature 28,
The transmission of power between the motors 4 and 28 can be reliably shut off, and generation of abnormal noise and vibration and heat generation due to sliding of the motors 24 and 28 can be prevented.

(1-3) The piston 35 is mounted on the rotating support 3
0, the hinge mechanism 32, the swash plate 31, and the shoe 36 are connected to the drive shaft 16. Therefore, as described above, the fact that the sliding movement of the drive shaft 16 to the rear side of the axis L can be prevented leads to the prevention of the piston 35 sliding to the valve / port forming body 14 side. as a result,
The piston 3 during the inertial rotation until the compressor completely stops
5 can be prevented from colliding with the valve / port forming body 14 when it is located at the top dead center.
Generation of noise can be suppressed. Also, piston 3
5 based on the collision between the valve 5 and the valve / port formation body 35,
Breakage of the compressor 14 is also avoided, which in turn leads to improved durability of the compressor.

(2) The capacity control valve 46 opens and closes the air supply passage 44 so that the high-pressure discharge refrigerant gas is supplied to the crank chamber 15.
To adjust the discharge capacity of the compressor. Therefore, for example, the bleed passage 45 is opened and closed, and the crank chamber 1 is opened.
By adjusting the amount of refrigerant gas (lower pressure than the discharged refrigerant gas) flowing out of the compressor 5 to the suction chamber 37, the crank chamber 15 can be quickly pressurized as compared with a configuration in which the discharge capacity of the compressor is adjusted. Therefore, if the compressor is stopped,
The discharge capacity can be minimized quickly, and the next start-up of the compressor immediately after the stop can be started from the minimum discharge capacity. From another point of view, compared with the case where the displacement control valve 46 opens and closes only the bleed passage 45 to adjust the discharge displacement, the problem that the pressure in the crank chamber 15 is excessively increased easily occurs. The effect provided by providing is more effectively achieved.

(3) The pressure-sensitive chamber 55 of the capacity control valve 46 is connected to the suction chamber 37 via the detection passage 47. That is, the bellows 56 operates the check valve 92 in the suction pressure region.
The opening / closing position (the contact portion between the valve seat 93 and the valve element 94) is operated in accordance with the pressure on the suction chamber 37 side. Therefore,
As described above, when the pressure in the suction chamber 37 increases when the check valve 92 is closed, the capacity control valve 46 decreases the opening of the valve hole 53 in accordance with the increase in pressure, and the pressure in the crank chamber 15 decreases. An operation for preventing a rapid rise is performed. That is, from the side where the pressure increase in the crank chamber 15 is prevented, the pressure difference between the cylinder bore 33 and the cylinder bore 33 can be prevented from being excessively increased, and the effect (1) can be more effectively achieved.

(4) For example, disposing the check valve 92 on the piping of the external refrigerant circuit 71 does not depart from the gist of the present invention. In such a configuration, a change in the configuration of the existing piping is forced. However, in the present embodiment, by arranging the check valve 92 in the rear housing 13 of the compressor, the existing piping of the external refrigerant circuit 71 can be used as it is, and the present invention is applied to the compressor. It can be applied to the refrigeration circuit only by changing the configuration.

Further, the check valve 92 disposed in the rear housing 13 can shut off the refrigerant flow passage between the evaporator 74 and the position near the suction chamber 37. That is, the suction chamber 37 side of the refrigerant flow path can be shut off from the evaporator 74 side by the check valve 92 with a smaller volume, and the pressure can be quickly increased by the inflow of the refrigerant gas from the crank chamber 15. This is more effective in achieving the effect (1).

(5) All of the components of the check valve 92 are housed in a case 96, and the check valve 92 is fixed to the housing chamber 91 with the case 96. Therefore, for example, the accommodation room 91
The valve seat 93 is directly formed therein, and the time and effort for assembling the check valve 92 in the narrow rear housing 13 can be saved as compared with a configuration in which the valve body 94 is movably accommodated. Also, the rear housing 13 of the case 96
Is fixed by press-fitting. For example, the work of fixing the check valve 92 in the narrow rear housing 13 can be easily performed as compared with another example of FIG.

(6) For example, the electromagnetic structure 60, 61, 63, 64 of the capacity control valve 46 is changed, and the suction force generated between the fixed iron core 60 and the movable iron core 61 increases the opening degree of the valve hole 53. A configuration in which the load is applied to the valve body 52 as a load in the direction in which the load is applied does not depart from the gist of the present invention. That is, the larger the input current value to the electromagnetic coil 64, the higher the set suction pressure is set. In this case, in particular, in order to change the discharge capacity to the minimum when the vehicle engine Eg is stopped, in other words, in order to set the set suction pressure to the maximum value, the power supply line between the electromagnetic coil 64 and the power supply S must be connected. In addition, a special configuration is required so as not to be interrupted on the upstream side of the control computer C, and a large structural change is required for the existing vehicle power supply system.

However, the capacity control valve 46 of the present embodiment is
The configuration is such that the set suction pressure is set higher as the input current value to the electromagnetic coil 64 decreases. Therefore, when the set suction pressure is set to the maximum value, the control computer C stops supplying power to the electromagnetic coil 64. This is because when the vehicle engine Eg stops, the power supply line between the electromagnetic coil 64 and the power supply S is supplied from the control computer C. Also results in the same condition as being shut off upstream. Therefore, a configuration in which the discharge capacity is minimized when the vehicle engine Eg is stopped can be achieved without forcing a structural change to the existing vehicle power supply system.

The present invention can be implemented in the following modes without departing from the spirit of the present invention. ○ The check valve should be composed of a reed valve. For example, FIG.
As shown in (1), a check valve 98 composed of a reed valve has one end fixed to the inner wall surface of the suction chamber 37 with a bolt 98a. The check valve 98 is connected to the pressure on the suction chamber 37 side and the evaporator 74.
The opening to the suction chamber 37 of the suction passage 90 is opened and closed by the difference from the pressure on the side. The check valve 98 made of a reed valve can reduce the size and simplify the configuration as compared with the spool valve configuration of the above embodiment. In addition, the check valve 98 disposed in the suction chamber 37 can shut off the suction chamber 37 from the evaporator 74 with a smaller volume, and quickly increase the pressure by the inflow of the refrigerant gas from the crank chamber 15. be able to.

In the above embodiment, the capacity control valve 46
Are pressure sensitive (56, 58 etc.) and electromagnetic (60, 6
1, 63, 64 etc.) to operate the valve body 52,
Although the configuration is such that the air supply passage 44 is opened and closed, this is changed. For example, as in the prior art of FIG. 9, the valve body 52 is operated only by the electromagnetic configuration to open and close the air supply passage 44. thing.

The displacement control valve 46 is configured to adjust the discharge displacement by opening and closing both the supply passage 44 and the bleed passage 45. In this case, it is important that the bleed passage 45 is not completely closed, that is, that the bleed passage 45 is always in communication.

The capacity control valve 46 is configured to adjust the discharge capacity by opening and closing only the bleed passage 45. Also in this case, it is important that the bleed passage 45 is always in communication.

(8) The present invention is embodied in a wobble type variable displacement compressor. The technical idea that can be grasped from the above embodiment will be described. (1) The set suction pressure changing means has an electromagnetic structure
5. The variable displacement compressor according to claim 4, wherein the set suction pressure is made higher as the input current value becomes smaller.

In this way, in order to set the set suction pressure to the maximum value, the input current value to the capacity control valve 46 (electromagnetic coil 64) may be set to zero. There is no need for a special configuration in which the power supply line is not interrupted upstream of the control computer C.

(2) The check valve comprises a spool valve 92, and all the components 93 to 95 constituting the spool valve are housed in a case 96, and are arranged in the housing 13 with the case 96. The variable displacement compressor according to claim 5.

In this case, for example, the housing 1
As compared with a configuration in which the valve seat 93 is directly formed in the third housing 3 and the valve body 94 is accommodated, the labor for assembling the check valve 92 in the narrow housing 13 can be omitted.

(3) The variable displacement compressor according to any one of claims 1 to 5, wherein the check valve comprises a reed valve 98. In this way, the configuration of the check valve 98 can be simplified.

[0088]

According to this embodiment having the above structure, the check valve is provided on the refrigerant flow path between the suction chamber and the evaporator of the external refrigerant circuit, so that the pressure in the cylinder bore can be maintained even after the compressor is stopped. Can be kept high, and excessive expansion of the difference from the pressure in the crankcase can be prevented. Therefore, it is possible to prevent the drive shaft from sliding in the axial direction against the urging force of the drive shaft urging member.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a variable displacement compressor.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a longitudinal sectional view of the displacement control valve.

FIG. 4 is a diagram illustrating an arrangement of a piston.

FIG. 5 is a diagram illustrating an off state of a friction clutch.

FIG. 6 is a diagram illustrating a state in which a check valve closes a suction passage.

FIG. 7 is a graph showing a change in each pressure with respect to an elapsed time from a stop of the compressor.

FIG. 8 is an enlarged sectional view of a main part near a check valve, showing another example.

FIG. 9 is a longitudinal sectional view of a conventional variable displacement compressor.

[Description of Signs] 11... Front Housing Constituting Housing, 12
... Cylinder block, 13 ... Rear housing, 14 ... Valve / port forming body, 15 ... Crank chamber, 16
.., A drive shaft, 20 a drive shaft biasing spring as a drive shaft biasing member, 31 a swash plate as a cam plate, 33 a cylinder bore, 35 a piston, 37 a suction chamber, 38 a discharge forming a discharge pressure region. Chamber, 39 ... suction port, 40 ... discharge port, 41 ... suction valve, 42 ... discharge valve, 44 ... air supply passage, 45 ... bleed passage, 46 ... capacity control valve, 71 ... compressor constitutes a refrigeration circuit External refrigerant circuit, 71a: piping forming a refrigerant flow path, 74: evaporator, 90: suction passage forming a refrigerant flow path, 92: check valve.

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[Procedure amendment]

[Submission date] May 17, 2000 (2005.1.
7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIG. 7

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H045 AA04 AA13 AA27 BA33 BA38 CA01 CA02 CA03 CA28 DA13 DA25 EA33 EA45 3H076 AA06 BB01 BB21 BB33 BB43 CC12 CC17 CC20 CC43 CC86 CC92

Claims (5)

[Claims] 1. A variable displacement compressor applied to a refrigeration circuit for compressing a refrigerant gas, wherein a crank chamber, a cylinder bore, and a suction chamber are formed in a housing and driven so as to pass through the crank chamber. A shaft is rotatably held, a cam plate is connected to the drive shaft in the crank chamber so as to be integrally rotatable and a tilt angle can be changed, and a piston connected to the cam plate is reciprocally housed in the cylinder bore. A valve / port forming body having a suction port, a suction valve, a discharge port, and a discharge valve is mounted on the housing so as to partition a cylinder bore and a suction chamber adjacent to each other. A drive shaft biasing member that biases the drive shaft along the axis in a direction in which the piston separates from the valve / port forming body is interposed therebetween, The crank chamber and the discharge pressure region communicate with each other via an air supply passage, and the crank chamber and the suction chamber are always communicated with each other via a bleed passage, and are controlled by an external signal to control at least one of the supply passage or the bleed passage. A displacement control valve that changes the pressure in the crank chamber by adjusting the opening degree, and changes the inclination angle of the cam plate in accordance with the difference between the pressure in the crank chamber and the pressure in the cylinder bore through the piston to change the discharge capacity. In the variable displacement compressor having a configuration that adjusts the pressure, a check valve that opens or closes the refrigerant flow path due to a pressure difference between before and after the suction path and the evaporator of the external refrigerant circuit has a check valve. The check valve is a variable displacement compressor configured to close the refrigerant passage when the pressure on the suction chamber side becomes equal to or higher than the pressure on the evaporator side. 2. An electromagnetic friction clutch capable of interrupting power transmission is disposed between the drive shaft and an external drive source that rotationally drives the drive shaft. The friction clutch is rotatable by a housing. A rotor supported and operatively connected to an external drive source, an armature fixed to the drive shaft so as to be integrally rotatable and disposed opposite to the rotor, and the armature is attracted to the rotor by excitation to fasten the two together; The variable displacement compressor according to claim 1, further comprising: an electromagnetic coil capable of transmitting power. 3. The variable displacement compressor according to claim 1, wherein the displacement control valve is configured to adjust at least an opening degree of an air supply passage. 4. A valve body for opening and closing one of an air supply passage and a bleed passage, the capacity control valve being operatively connected to the valve body, and a pressure on a suction chamber side of an open / close position of a check valve in a suction pressure region. 2. A pressure-sensitive member for operating a valve element according to a pressure-sensitive member, and set suction-pressure changing means for changing a set suction pressure, which is controlled by an external signal, to serve as a reference for operation of the pressure-sensitive member. The variable displacement compressor according to any one of claims 1 to 3. 5. The variable displacement compressor according to claim 1, wherein said check valve is disposed in a housing.