KR20060050534A - Control valve for variable displacement compressor - Google Patents

Abstract

The present invention provides a control valve for a variable displacement compressor of the Pd-Ps differential pressure control system which can easily set the characteristics relating to the degree of the crank pressure influence on the change in the differential pressure between the discharge pressure and the suction pressure to desired characteristics. .

In the control valve for the variable displacement compressor, the effective hydraulic pressure area A on the discharge pressure side of the intermediate body in which the valve member 14 and the shaft 18 are integrated, and the effective hydraulic pressure area B on the suction pressure side of the intermediate body. Adjust the difference between As a result, desired differential pressure and crank pressure characteristics in accordance with the specifications of the control valve for the variable displacement compressor are obtained. Since the change of the effective hydraulic pressure area hardly affects the current value and the differential pressure characteristic which is a relationship between the current value supplied to the solenoid 2 and the differential pressure between the discharge pressure Pd and the suction pressure Ps, it is easily It can be realized.

Valve member, shaft, effective hydraulic pressure area, suction pressure, discharge pressure, solenoid

Description

CONTROL VALVE FOR VARIABLE DISPLACEMENT COMPRESSOR

1 is a cross-sectional view showing a configuration of a control valve for a variable displacement compressor according to an embodiment.

Figure 2 is an enlarged top view of Figure 1;

3 is an explanatory diagram showing differential pressure and crank pressure characteristics of a control valve for a variable displacement compressor.

<Explanation of symbols for the main parts of the drawings>

1: valve component

2: solenoid

3: upper body

4: discharge pressure port

6: crank pressure port

7: suction pressure port

8: crankcase communication room

9: guide hole

10: valve seat forming member

12: valve hole

13: valve seat

14: valve member

15: holder

16: ball

18, 28: shaft

19: lower body

20: core

26: bearing member

27: plunger

33: electronic coil

A, B: effective hydraulic pressure area

Pc: crank pressure

Pd: discharge pressure

Ps: suction pressure

[Patent 1] Japanese Patent Laid-Open No. 2003-328936 (paragraphs [0040] to [0045], FIG. 3)

The present invention relates to a control valve for a variable displacement compressor, and more particularly to a control valve for a variable displacement compressor for controlling the discharge capacity of the refrigerant by the variable capacity compressor of the automotive air conditioner.

Since the compressor used for the refrigeration cycle of the vehicle air conditioner uses an engine whose rotation speed changes in accordance with the running state, the rotation speed control cannot be performed. Therefore, in general, a variable displacement compressor capable of varying the discharge capacity of the refrigerant is used in order to obtain an appropriate cooling capability without being limited by the rotational speed of the engine.

In this variable displacement compressor, an inclined plate provided at a variable inclination angle is generally driven by a rotational motion of a rotating shaft in a crank chamber formed in a hermetic seal, and oscillates, and a reciprocating motion in a direction parallel to the rotating shaft is performed by the rotating motion of the inclined plate. The piston sucks the refrigerant in the suction chamber into the cylinder, compresses it, and discharges it into the discharge chamber. At this time, by changing the pressure in the crank chamber, the inclination angle of the inclined plate can be changed, whereby the stroke of the piston is changed, and the discharge amount of the coolant is changed. It is a control valve for a variable displacement compressor that controls to change the pressure in this crank chamber.

A control valve for variable capacity compressors for variably controlling the discharge capacity of such a variable capacity compressor is generally designed to reduce a portion of the refrigerant of the discharge pressure Pd discharged from the discharge chamber to introduce the crank chamber into a crank chamber, thereby controlling the introduction amount thereof. The pressure (crank pressure) Pc in the crank chamber is controlled. The introduction amount is controlled by supplying an external current to the solenoid provided in the control valve for the variable displacement compressor to drive control the internal valve member. Specifically, a method performed according to the suction pressure Ps of the suction chamber, for example, have. This control controls the flow rate of the refrigerant of the discharge pressure Pd introduced from the discharge chamber to the crank chamber so that the suction pressure Ps is kept constant by reacting the suction pressure Ps. When entering the variable capacitance operation, the value of the suction pressure Ps can be freely set by the amount of current supplied to the solenoid.

However, in order to perform the capacity control based on the suction pressure Ps as described above, a flexible member such as a diaphragm or a bellows for sensing the suction pressure Ps is disposed in the inside of the control valve for the variable displacement compressor. It is necessary to do it, and the apparatus tends to be relatively large.

For this reason, a control method based on the differential pressure Pd-Ps between the discharge pressure Pd and the suction pressure Ps is taken as a different control method (hereinafter, this control is referred to as "Pd-Ps differential pressure control"). box). This Pd-Ps differential pressure control reacts the differential pressures Pd-Ps between the discharge pressure Pd and the suction pressure Ps, and discharges introduced into the crank chamber from the discharge chamber so that the differential pressures Pd-Ps are kept constant. The flow rate of the refrigerant at the pressure Pd is controlled. The control valve for a variable displacement compressor of such a control system has the same effective hydraulic pressure area with respect to the discharge pressure Pd of the intermediate body which consists of a valve member, a piston rod, etc., and an effective hydraulic pressure area with respect to the suction pressure Ps in the intermediate body. Thus, the crank pressure Pc loaded on the intermediate body is configured to be canceled. Thereby, the valve part of the control valve for variable displacement compressors is made to open and close by the differential pressure Pd-Ps of discharge pressure Pd and suction pressure Ps irrespective of crank pressure Pc (for example, See, for example, Patent Document 1).

According to the control valve for the variable displacement compressor of such a control system, in order to receive the discharge pressure Pd and the suction pressure Ps directly as a valve member, and to sense the differential pressure, the above-mentioned flexible member becomes unnecessary. In addition, in particular, since the discharge pressure Pd is directly sensed, the pressure fluctuation of the variable displacement compressor can be effectively reflected, and capacity control with good responsiveness can be realized.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-328936 (paragraphs [0040] to [0045], FIG. 3)

As described above, in the Pd-Ps differential pressure control, the differential pressure (Pd-Ps) between the discharge pressure Pd and the suction pressure Ps is constant according to the current value energized by the solenoid regardless of the original crank pressure Pc. It is controlled to terminate. However, in practice, the crank pressure Pc is increased by increasing the differential pressures Pd-Ps, and on the contrary, the differential pressures Pd-Ps also change somewhat under the influence of the fluctuation of the crank pressure Pc. Specifically, as the crank pressure Pc increases, the differential pressure Pd-Ps increases with a slight inclination.

This can be said to be not ideal only in terms of the characteristics of the control valve for the variable displacement compressor, but this is not necessarily the case when a control matching with the variable displacement compressor is considered. That is, when the differential pressure (Pd-Ps) rises at a constant level with respect to the change in the current value supplied to the solenoid, the valve portion is opened momentarily to improve the responsiveness of the inclined plate of the variable displacement compressor, while hunting or overloading the capacity control. A chute may be generated, making stable control difficult. On the other hand, if the rise of the differential pressures Pd-Ps with respect to the current value is slow, the response of the inclined plate is deteriorated. Further, even at the same current value, the value of the differential pressure Pd-Ps to be controlled is changed by the value of the crank pressure Pc. This is sometimes connected to the hysteresis of the capacity control, which is undesirable for the control of the variable capacity compressor. For this reason, it is said that it is desirable to raise the differential pressure (Pd-Ps) to appropriate responsiveness (tilt) according to a current value. For example, when the inclined plate of the variable capacity compressor is difficult to move, it is required to increase the responsiveness to improve the movement of the inclined plate, and conversely, when the inclined plate moves excessively easily, it is required to lower the responsiveness to stabilize the inclined plate movement.

For this reason, according to the characteristic required for the control valve for variable displacement compressor conventionally, by changing the characteristic of the spring which presses a valve member to the operation direction, changing the suction force characteristic of a solenoid, etc. of a differential pressure (Pd-Ps), Adjusting the degree (tilt) of the influence of the crank pressure Pc on the change was performed. However, if the characteristics of the spring and the attraction force of the solenoid are changed in this way, the differential pressure characteristic, which is the relationship between the current value and the differential pressure (Pd-Ps), may be changed, and the overall tuning becomes difficult.

The present invention has been made in view of this point, and the variable capacity of the Pd-Ps differential pressure control system which can easily set the characteristics relating to the degree of the crank pressure influence on the change in the differential pressure between the discharge pressure and the suction pressure can be set to the desired characteristics. It is an object to provide a control valve for a compressor.

In the present invention, in order to solve the above problem, in the control valve for a variable displacement compressor mounted on the variable displacement compressor to control the pressure in the crankcase to change the discharge capacity of the refrigerant, the discharge to introduce the discharge pressure of the variable displacement compressor A pressure port, a crank pressure port for introducing the crank pressure generated therein into the crank chamber, a suction pressure port for introducing suction pressure, are sequentially installed from one end side, and are provided between the discharge pressure port and the crank pressure port. A valve member that contacts and separates the valve seat and decompresses the discharge pressure introduced from the discharge pressure port through an throttle flow path formed between the valve seats to generate the crank pressure, and the valve member opens or closes the valve. In the direction and operable integrally with the valve member And an electromagnetic coil connected to an end opposite to the discharge pressure port of the body, the plunger being integral with the valve member via the shaft, and the magnetic coil including the plunger and the core by energization. A solenoid comprising: a difference between an effective hydraulic pressure area for the discharge pressure in the intermediate body in which the valve member and the shaft are integrated, and an effective hydraulic pressure area for the suction pressure in the intermediate body. Thereby, a control valve for a variable displacement compressor is provided, wherein the degree of influence of the crank pressure on the change in the differential pressure between the discharge pressure and the suction pressure is adjusted.

In addition, although the "plunger which can be integrated with a valve member through a shaft" is used, the plunger does not have to be directly connected to the shaft, but may be connected to the shaft through an inclusion of a separate member.

In such a variable displacement compressor control valve, in the differential pressure control based on the differential pressure between the discharge pressure and the suction pressure, the effective hydraulic pressure area on the discharge pressure side of the intermediate body and the effective hydraulic pressure area on the suction pressure side of the intermediate body are set to be the same as the original. Intentional balance breaks. Then, by adjusting the difference of the effective hydraulic pressure area, the characteristics relating to the degree of crank pressure influence on the change in the differential pressure between the discharge pressure and the suction pressure (hereinafter referred to as "differential pressure / crank pressure characteristic") are adjusted to be desired characteristics. do. However, both effective hydraulic pressure areas can be made equal by the characteristics to be required.

In addition, the change in the effective hydraulic pressure area hardly affects the relationship between the current value supplied to the solenoid and the differential pressure between the discharge pressure and the suction pressure (hereinafter referred to as "current / differential pressure characteristic").

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings.

1 is a cross-sectional view showing the configuration of a control valve for a variable displacement compressor according to the present embodiment, and FIG. 2 is an enlarged top view of FIG.

As shown in Fig. 1, the control valve for the variable displacement compressor is a control valve which introduces a part of the discharge refrigerant of the variable displacement compressor (not shown), controls the refrigerant flow rate, and introduces the refrigerant into the crank chamber. It is comprised by integrally attaching and attaching the valve structure part 1 which has a valve part to adjust inside, and the solenoid 2 for controlling the valve opening degree of the valve part.

The valve component 1 constitutes a discharge pressure port 4 in which the upper end opening of the stepped cylindrical upper body 3 communicates with the discharge chamber of the variable displacement compressor to receive the discharge pressure Pd, and the upper body ( A strainer 5 is attached to cover the upper edge of 3). The discharge pressure port 4 communicates internally with the crank pressure port 6 opened at the center side of the upper body 3, and the crank pressure port 6 communicates with the crank chamber of the variable displacement compressor, and the crank The controlled pressure (crank pressure) Pc in the seal is derived. In addition, a suction passage 7 for opening a suction pressure Ps in communication with the suction chamber of the variable displacement compressor is opened at the lower side of the upper body 3, and a refrigerant passage connected to the suction pressure port 7 is provided. Is switched downward from the inside of the upper body 3, and is open to the lower end face of the upper body 3.

A crankcase communication chamber 8 in which the crank pressure Pc is satisfied is formed between the discharge pressure port 4 and the crank pressure port 6 in the upper portion of the upper body 3. In the lower center part of the upper body 3, the guide hole 9 which penetrates this in the axial direction, penetrates the shaft mentioned later, and guides it is formed. This guide hole 9 communicates with the crank chamber communication chamber 8 at the upper end opening portion.

A stepped cylindrical valve seat forming member 10 is disposed in the upper portion of the upper body 3 so as to be inserted into the crank chamber communication chamber 8.

As shown in Fig. 2, the valve seat forming member 10 has its upper outer circumferential portion pressed into the upper end of the upper body 3, and its lower portion once shrinks the tube and moves the inside of the crankcase communication chamber 8 downward. It is extended. The communication end 11 which communicates inside and outside is provided in the base end part of this tube reduction part. Moreover, the valve hole 12 is formed in the inner middle part of the valve seat formation member 10 so that each space of the discharge chamber side and the crank chamber side may communicate, and the opening edge part of the crank chamber side of this valve hole 12 is a valve | bulb. The sheet 13 is constituted.

In the lower opening part of the valve seat formation member 10, the valve member 14 is arrange | positioned so that an advance and retraction may be carried out in the axial direction. This valve member 14 is comprised from the holder 15 which can slide along the inner wall of the valve seat formation member 10, and the ball 16 press-fitted in the upper end center part of the holder 15. As shown in FIG. The upper outer peripheral part of the holder 15 has diameter reduced, and the spring 17 is externally inserted in the diameter reduction part. This spring 17 is interposed between the valve seat forming member 10 and the holder 15, and presses the ball 16 in the direction away from the valve seat 13. Moreover, the communication hole 15a which communicates inside and outside is provided in the side part of the holder 15. As shown in FIG. The ball 16 is operated integrally with the holder 15, and can be seated. The discharge pressure Pd introduced from the discharge pressure port 4 is reduced in pressure by passing through the throttle flow path between the ball 16 and the valve seat 13, whereby the crank pressure Pc is generated.

Returning to Fig. 1, the shaft 18 is inserted through the guide hole 9 of the upper body 3 so as to be able to move forward and backward in the axial direction. One end of the shaft 18 penetrates the holder 15 to contact the ball 16, and the other end extends below the upper body 3.

In this way, the contact position with the valve member 14 of the shaft 18 is not the holder 15 but the ball 16 in front of the holder 15, so that the valve member 14 is balanced. Function. As a result, since the movement of the valve member 14 in the transverse direction is suppressed, the valve member 14 can perform the axial retreat movement in a stable state with the transverse load reduced. Further, by reducing the lateral load to the valve member 14 generated at the time of the forward and backward movement, the hysteresis is reduced in the opening / closing characteristics of the valve, and the displacement of the valve member 14 is suppressed, thereby completely closing the valve member 14. You can expect.

The upper opening of the lower body 19 is caulked and joined to the lower part of the upper body 3, and the core 20 of the solenoid 2 is screwed to the lower end of the upper body 3. The central opening 21 penetrates through the axis position of the core 20, and the communication hole 22 which penetrates from the circumference and communicates with the center opening 21 in the upper part of the core 20, and the core 20 of The communication hole 23 which opens toward the upper end part, communicates with the refrigerant passage connected to the suction pressure port 7 on one side, and communicates with the communication hole 22 on the other side, is provided. As a result, the suction pressure Ps is pressurized to the end of the shaft 18.

The sleeve 24 is disposed inside the lower body 19. A lid-shaped stopper 25 is fitted to the lower opening of the sleeve 24 in the drawing, and a ring-shaped bearing member 26 is press-fitted into the inner circumferential portion of the stopper 25. In the sleeve 24, a core 20 and a plunger 27 screwed to the upper body 3 are arranged. This plunger 27 has one end supported by the lower end opening of the upper body 3 through the core 20, and the other end fixedly attached to the shaft 28 supported by the bearing member 26. Movement in the direction of the shaft 18 is regulated by the fixing ring 29 fitted to 28. As a result, the plunger 27 is able to move back and forth in the axial direction without contacting the sleeve 24. In addition, a spring 30 is disposed between the core 20 and the plunger 27, and a spring 31 is disposed between the plunger 27 and the bearing member 26.

The outer periphery of the sleeve 24 is provided with the yoke 32, the electromagnetic coil 33, and the case 34 surrounding them, and together with the core 20 and the plunger 27, the solenoid 2 is formed. The lower end of the case 34 is provided with a handle 36 through which the harness 35 is inserted, and the lower end of the solenoid 2 is closed.

Next, the operation of the control valve for the variable displacement compressor will be described together with the operation of the variable displacement compressor.

Inside the control valve for the variable displacement compressor, the discharge pressure Pd of the refrigerant introduced from the discharge chamber is applied to the ball 16 from the upper direction in the figure. On the other hand, the suction pressure Ps of the suction chamber is introduced into the central opening 21 through the suction pressure port 7 and the communication holes 23 and 22 to the shaft 18 in contact with the ball 16. The clearance between the upper body 3 and the shaft 28 is applied downward in the figure. For this reason, if the diameter of the shaft 18 (that is, the diameter of the guide hole 9) and the diameter of the valve hole 12 are the same, the effective hydraulic pressure area of the discharge pressure Pd in the ball 16, The effective hydraulic pressure area of the suction pressure Ps in the shaft 18 becomes equal. Therefore, the crank pressure Pc, which is loaded on the intermediate body in which the valve member 14 and the shaft 18 are integrated, is canceled, and the ball 16 which controls the flow rate of the refrigerant flowing from the discharge chamber to the crank chamber is discharged ( The differential pressure valve which operates by reacting the differential pressure between Pd) and the suction pressure Ps is constituted. However, in the present embodiment, by adjusting one of such effective hydraulic pressure areas, such as by increasing the difference in the effective hydraulic pressure area, the characteristics relating to the degree of crank pressure influence on the change in the differential pressure between the discharge pressure and the suction pressure Adjust so that (differential pressure / crank pressure characteristic) is a desired characteristic. This will be described later in detail.

In the control valve for the variable displacement compressor, when the control current is supplied to the electromagnetic coil 33 of the solenoid 2, since the discharge pressure Pd pushes the ball 16 to open, the ball 16 is completely. Open state. As a result, in the variable displacement compressor, the crank pressure Pc becomes a value close to the discharge pressure Pd, and in the piston for suction compression of the refrigerant provided to face the crank chamber, the pressure difference on both surfaces thereof is the smallest. Therefore, the inclined plate in the crank chamber that determines the stroke of the piston has the inclination angle which makes the stroke the smallest, and the variable displacement compressor performs the operation of the minimum capacity.

In addition, when the maximum control current is supplied to the electromagnetic coil 33 of the solenoid 2, the plunger 27 is attracted to the core 20 and moves upward in the drawing, whereby the shaft 28 and the shaft ( 18) is pushed upwards in the figure so that the ball 16 is fully closed. At this time, since the crank chamber communicates with the suction chamber through a fixed orifice (not shown), the refrigerant in the crank chamber flows through the fixed orifice to the suction chamber, and the crank pressure Pc is close to the suction pressure Ps of the suction chamber. Decrease to value. As a result, the pressure difference with respect to both sides of the piston is greatest, and the inclined plate has an inclination angle in which the stroke of the piston is greatest, and the variable displacement compressor shifts to the operation of the maximum capacity.

Here, in the case where normal control in which a predetermined control current is supplied to the electromagnetic coil 33 of the solenoid 2 is performed, the plunger 27 is attracted to the core 20 in accordance with the magnitude of the control current. The force to move a predetermined amount in the upper direction of is generated. This force becomes the set value of the control valve for the variable displacement compressor operating as the differential pressure valve. Therefore, the control valve for the variable displacement compressor senses the pressure difference between the discharge pressure Pd and the suction pressure Ps and removes the pressure difference from the discharge chamber so as to maintain the pressure difference corresponding to the value set by the solenoid 2. The operation of controlling the flow rate of the refrigerant flowing into the crank chamber is performed.

Next, the adjustment method of the differential pressure and crank pressure characteristic in the control valve for variable displacement compressor mentioned above is demonstrated.

In this embodiment, the effective hydraulic pressure area A on the discharge pressure side of the intermediate body in which the valve member 14 and the shaft 18 shown in FIG. 2 are integrated, the effective hydraulic pressure area B on the suction pressure side, and By adjusting the difference, the desired differential pressure and crank pressure characteristics are obtained. In addition, the effective hydraulic pressure area A on the discharge pressure side is adjusted by adjusting the diameter of the valve hole 12, and the diameter of the shaft 18 (that is, the guide hole 9 on the effective hydraulic pressure area B on the suction pressure side). Diameter]). Fig. 3 is an explanatory diagram showing the differential pressure and crank pressure characteristics of the control valve for the variable displacement compressor, and Fig. 3A is the same as the effective hydraulic pressure area A and the effective hydraulic pressure area B. (b) shows the case where the effective hydraulic pressure area A is smaller than the effective hydraulic pressure area B, and FIG.3 (c) has shown the case where the effective hydraulic pressure area A is larger than the effective hydraulic pressure area B, respectively.

As shown in Fig. 3A, when the effective hydraulic pressure area A on the discharge pressure side and the effective hydraulic pressure area B on the suction pressure side are the same, even if the current value supplied to the solenoid 2 is constant, discharge is performed. The differential pressure Pd-Ps between the pressure Pd and the suction pressure Ps slightly changes under the influence of the crank pressure Pc. This differential pressure Pd-Ps changes according to the magnitude | size of the electric current value Isol supplied to the solenoid 2.

That is, since the effective hydraulic pressure area A on the discharge pressure side and the effective hydraulic pressure area B on the suction pressure side are the same, the original crank pressure Pc is canceled, and the differential pressures Pd-Ps are the crank pressure Pc. It is difficult to completely exclude the influence of the crank pressure Pc, which becomes a constant value regardless of the actual value, and a slight inclination to the characteristic can be seen as shown in the above figure.

As shown in Fig. 3B, when the effective hydraulic pressure area A is set smaller than the effective hydraulic pressure area B, the crank pressure ( The balance of Pc is broken, and the contribution to the valve opening direction by this crank pressure Pc becomes large, and the valve part is opened more easily. As a result, the differential pressure Pd-Ps rises rapidly, and the influence of the crank pressure Pc becomes smaller than when the effective hydraulic pressure area A and the effective hydraulic pressure area B are the same, and the responsiveness of the inclined plate of the variable displacement compressor This is improved.

As shown in Fig. 3 (c), when the effective hydraulic pressure area A is set to be larger than the effective hydraulic pressure area B, the crank pressure (for the intermediate body in the state in which the valve member 14 and the shaft 18 are integrated) The balance of Pc is broken, and the contribution to the valve closing direction by this crank pressure Pc becomes large, and the valve part is opened more difficult. As a result, the differential pressures Pd-Ps gradually rise, and the influence of the crank pressure Pc becomes larger than the case where the effective hydraulic pressure area A and the effective hydraulic pressure area B are the same. Lowers.

As described above, the differential pressure / crank pressure characteristics can be changed by adjusting the difference between the effective hydraulic pressure area A and the effective hydraulic pressure area B. FIG. For this reason, for example, when the responsiveness of the inclined plate of the variable displacement compressor is particularly desired to be improved from the conventional characteristics, the effective hydraulic pressure area A may be configured to be smaller than the effective hydraulic pressure area B. When responsiveness is desired to be gentler than the conventional characteristics, the effective hydraulic pressure area A may be configured to be larger than the effective hydraulic pressure area B.

As explained above, in the control valve for variable displacement compressors of the present embodiment, the effective hydraulic pressure area A on the discharge pressure side of the intermediate body in which the valve member 14 and the shaft 18 are integrated, and the intermediate body. The difference with the effective hydraulic pressure area B on the suction pressure side of the side is appropriately adjusted. As a result, desired differential pressure and crank pressure characteristics in accordance with the specifications of the control valve for the variable displacement compressor are obtained. Since the change of the effective hydraulic pressure area hardly affects the current value and the differential pressure characteristic, which is a relationship between the current value supplied to the solenoid 2 and the differential pressure between the discharge pressure Pd and the suction pressure Ps, it is easily realized. Can be.

According to the control valve for a variable displacement compressor of the present invention, by adjusting the difference between the effective hydraulic pressure area on the discharge pressure side of the intermediate body with the valve member and the shaft integrated, and the effective hydraulic pressure area on the suction pressure side of the intermediate body, Differential pressure and crank pressure characteristics are obtained. Since the change of the effective hydraulic pressure area hardly affects the differential pressure characteristic which is the relationship between the current value supplied to the solenoid and the differential pressure between the discharge pressure and the suction pressure, the desired differential pressure and crank pressure characteristics can be easily obtained.

Claims (4)

A control valve for a variable displacement compressor mounted on a variable displacement compressor to control the pressure in the crankcase to change the discharge capacity of the refrigerant. A body in which a discharge pressure port for introducing a discharge pressure of the variable displacement compressor, a crank pressure port for introducing a crank pressure generated therein into the crank chamber, and a suction pressure port for introducing a suction pressure are sequentially provided from one end side; A valve member for contacting and separating the valve seat provided between the discharge pressure port and the crank pressure port, and reducing the discharge pressure introduced from the discharge pressure port through a throttle flow path formed between the valve seats to generate the crank pressure. Wow, A shaft supporting the valve member in a valve opening or valve closing direction and operable integrally with the valve member; An electromagnetic coil connected to an end opposite to the discharge pressure port of the body, the plunger being integral with the valve member through the shaft, and energizing the magnetic circuit including the plunger and the core by energization. With a solenoid made of, By adjusting the difference between the effective hydraulic pressure area with respect to the discharge pressure in the intermediate body in which the valve member and the shaft are integrated, and the effective hydraulic pressure area with respect to the suction pressure in the intermediate body, the discharge pressure and the A control valve for a variable displacement compressor, characterized by adjusting the degree of influence of the crank pressure on the change of the differential pressure with the suction pressure. The crankcase communication chamber according to claim 1, wherein between the valve seat and the crank pressure port of the body, the generated crank pressure is satisfied and at the same time the valve member is disposed, On the opposite side to the discharge pressure port of the body, a guide hole is formed coaxially with the valve hole defining the valve seat and opened in the crank chamber communication chamber, and the guide hole for inserting and guiding the shaft is formed. , The shaft is configured to receive the suction pressure on the side opposite to the crank chamber communication chamber with respect to the guide hole, The effective hydraulic pressure area with respect to the said discharge pressure in the said intermediate body is adjusted by the cross-sectional area size of the said valve hole, The effective hydraulic pressure area with respect to the said suction pressure in the said intermediate body is adjusted by the cross-sectional area size of the said guide hole, The control valve for variable displacement compressors characterized by the above-mentioned. The pressure difference area between the discharge pressure and the suction pressure is determined by causing the effective hydraulic pressure area with respect to the discharge pressure in the intermediate body to be larger than the effective hydraulic pressure area with respect to the suction pressure in the intermediate body. A control valve for a variable displacement compressor, characterized in that the degree of influence of the crank pressure on the change is larger than when both effective hydraulic pressure areas are equal. The pressure difference area between the discharge pressure and the suction pressure is determined by making the effective hydraulic pressure area with respect to the discharge pressure in the intermediate body smaller than the effective hydraulic pressure area with respect to the suction pressure in the intermediate body. A control valve for a variable displacement compressor, characterized in that the degree of influence of the crank pressure on the change is smaller than when both effective hydraulic pressure areas are equal.

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