WO2001002726A1

WO2001002726A1 - Control valve for variable displacement compressor

Info

Publication number: WO2001002726A1
Application number: PCT/JP2000/004300
Authority: WO
Inventors: Ken Suitou; Kenta Nishimura; Satoshi Inaji; Ryo Matsubara; Morio Kaneko; Ichiro Ohkawara
Original assignee: Kabushiki Kaisha Toyoda Jidoshokki Seisakusho; Kabushiki Kaisha Saginomiya Seisakusho
Priority date: 1999-07-05
Filing date: 2000-06-29
Publication date: 2001-01-11
Also published as: EP1111237A1; BR0007004A; JP2001020857A; CN1317073A; KR20010079737A

Abstract

A control valve for variable displacement compressor, comprising a ball valve disc (37) which opens and closes communication passages (32, 34, 33) communicating a suction port with a crank chamber of a compressor and is energized in the valve closing direction by a spring force of a compressive coil spring (44), a bellows device (40) driving the ball valve disc (37) in the valve opening direction by the application of a suction pressure of the compressor, the ball valve disc (37) being connected directly with the bellows device (40) with the ball valve disc (37) used as a self-centering ball, and a delivery pressure leading hollow tube body (49) connected to the ball valve disc (37) at one end and applying a delivery pressure of the compressor directly in the valve opening direction of the ball valve disc (37) which is disposed in a valve housing (31), a compressive coil spring (50) energizing the ball valve disc (37) in the valve opening direction through the delivery pressure leading hollow tube body (49).

Description

Description Control valve for variable displacement compressor Technical field

The present invention relates to a control valve for a variable displacement compressor, and more particularly to a displacement control valve for a swash plate type variable displacement compressor used in an in-vehicle air conditioner or the like. Background art

As a capacity control valve for a swash plate type variable displacement compressor, Japanese Patent Publication No. 3-530474, Japanese Utility Model Publication No. 6-17010, Japanese Patent Publication No. The displacement control valve disclosed in the publication is conventionally known.

Basically, this displacement control valve reduces the displacement in response to a rise in the pressure in the crankcase of a compressor with a built-in swash plate, and increases the displacement in response to a decrease in the pressure in the crankcase. In a variable compressor, the communication passage connecting the suction port of the compressor and the crank chamber is provided with a valve opening force of a pressure responsive device that responds to the suction pressure of the compressor and a spring force of a valve closing spring. A control valve that opens and closes with a valve body driven by an equilibrium relationship, and controls a suction pressure of a compressor supplied to a crank chamber, and further exerts a discharge pressure of the compressor in a valve-opening direction. The opening and closing operation point is shifted according to the discharge pressure, and the capacity is controlled in accordance with the external air load (discharge pressure).

The above-mentioned conventional capacity control valves all achieve the intended purpose, but the number of parts and the number of assembling man-hours are increased, and capacity control is not possible if the valve is directly incorporated into the compressor housing. The passage structure for guiding the suction pressure and the discharge pressure to each part of the valve is complicated, and the degree of freedom of the arrangement position in the compressor housing is limited, so that these points cannot be sufficiently satisfied.

Diaphragm devices and bellows devices are available as pressure response devices, and the driving force of these pressure response devices must act as an axial force on the valve element. This causes the smoothness of the opening and closing movement of the valve body to be impaired. For this reason, in the conventional displacement control valve, a spring or an automatic A centripetal ball must be provided, which leads to an increase in the number of parts and assembly man-hours. Disclosure of the invention

The present invention has been made in view of the above-mentioned problems, and does not require a special automatic centering ball or the like, simplifies the structure, and increases the number of parts and the number of assembling steps. To provide a control valve for a variable displacement compressor, which has no complicated passage structure and has a high degree of freedom in the arrangement position in the compressor housing as a compressor housing built-in type. It is an object.

In order to achieve the above object, a control valve for a variable displacement compressor according to the invention described in claim 1 includes: a valve housing having a communication passage communicating a suction port of a compressor with a crank chamber; and the valve housing. A ball valve body provided in the housing for opening and closing the communication passage; a spring for urging the ball valve body in a valve closing direction; and directly connecting the ball valve body as an automatic centripetal ball to the ball valve body. A pressure responsive device that is driven by the suction pressure of the compressor to drive the ball valve body in the valve opening direction, slidably fitted to the valve housing, and joined at one end to the ball valve body; The other end has a discharge pressure introduction port for the compressor, and has a discharge pressure introduction hollow pipe body for applying the discharge pressure of the compressor to the back surface of the ball valve as a force in the valve opening direction through an internal passage. Is what

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view showing an embodiment of a variable displacement compressor incorporating a control valve according to the present invention.

FIG. 2 is a sectional view showing a first embodiment of a control valve for a variable displacement compressor according to the present invention.

FIG. 3 is a graph showing a discharge pressure-suction pressure characteristic of the control valve for a variable displacement compressor according to the first embodiment.

FIG. 4 is a sectional view showing a second embodiment of the control valve for a variable displacement compressor according to the present invention.

FIG. 5 is a sectional view showing a third embodiment of the control valve for a variable displacement compressor according to the present invention. It is. BEST MODE FOR CARRYING OUT THE INVENTION Specific Configuration of Control Valve for Variable Displacement Compressor According to First Preferred Embodiment of the Invention

First, a configuration of a control valve for a variable displacement compressor according to a first embodiment of the present invention will be described with reference to FIG. 1 to FIG.

As shown in FIG. 1, the swash plate type variable displacement compressor 1 includes a crank chamber 3 defined by a compressor housing 2 and a crank chamber 3 at one of the stroke ends. And a plurality of cylinder chambers 4 communicating with each other. A piston 5 is slidably fitted in each of the cylinder chambers 4 in the axial direction, and one end of a piston rod 6 is connected to the crank chamber 3 side of each piston 5.

The compressor housing 2 rotatably supports a drive shaft 7, and the drive shaft 7 is drivingly connected to an engine (not shown) by a drive belt (not shown) stretched over a pulley 8. Is driven to rotate.

The drive shaft 7 is connected to a wobbled plate (swash plate) 9 in the crankcase 3 by a known linking mechanism (not shown) in a torque transmitting relationship so that the mounting angle can be changed. A piston hole 6 is engaged with the side plate surface so that axial force can be transmitted.

The pivot 9 is rotated by the drive shaft 7 in an inclined state, so that the piston 5 of each cylinder chamber 4 moves forward and backward with a stroke corresponding to the inclination angle of the movable plate 9, and the inclination angle is reduced. The pressure is automatically adjusted according to the pressure difference between the crankcase pressure Pc and the suction pressure (compressor suction pressure) Ps of each cylinder chamber 4.

In this case, the compressor 1 reduces the discharge capacity by reducing the inclination angle of the wobble plate 9 and the stroke of the piston 5 in accordance with the rise of the crankcase pressure Pc, thereby reducing the discharge capacity. As the tilt angle of the wobble plate 9 increases in accordance with the decrease and the stroke of the piston 5 increases, the discharge capacity increases, and the crank chamber pressure P increases. When the pressure becomes substantially equal to the suction pressure Ps, a full load operation state is established. Each cylinder chamber 4 is formed with a suction port 14 having a one-way valve and a discharge port 15 having a discharge valve 13 and a discharge port 15 .The suction port 14 of each cylinder chamber 4 is The suction passage 16 communicates with the suction connection port 17, the discharge port 15 communicates with the discharge connection port 19 via the discharge passage 18, and the suction connection port 17 and the discharge connection port 19 communicate with each other. In addition, a circulation line for a refrigeration cycle including an evaporator 20, an expansion valve 21, a condenser 22 and the like is connected.

A control valve receiving hole 23 having a bottomed hole is formed in the compressor housing 2, and the control valve 30 according to the present invention is inserted and fixed in the control valve receiving hole 23.

The control valve 30 has a cylindrical valve housing 31 inserted into the control valve receiving hole 23.

As shown in FIG. 2, the valve housing 31 includes a crank chamber-side passage 32 and a suction port-side passage 33 extending radially across the middle of the valve housing 31. And a valve chamber 34 existing inside the valve housing 31 and between the crank chamber side passage 32 and the suction port side passage 33. An annular peripheral groove 35 for the crank chamber side passage 32 and an annular peripheral groove 36 for the suction port side passage 33 are formed on the outer peripheral portion of the valve housing 31.

A ball valve element 37 is disposed in the valve chamber 34, and the ball valve element 37 is selectively seated on the valve seat portion 38, whereby the crank chamber side passage 32 and the suction port side passage 3 are provided. Communication with 3 is cut off.

A bellows housing case 39 is caulked to one end (lower end) of the valve housing 31.

Inside the bellows storage case 39, a bellows device 40 having a closed structure, which is a pressure responsive device, is disposed. The bellows device 40 is constituted by a bellows-shaped bellows body 41 having an end plate 43 integrally at one end, and an end plate 42 closing the other end of the bellows body 41. Is at vacuum pressure. A compression coil spring 4 4 for urging the bellows device 40 in the extension direction (valve closing direction) is provided between the end plate 42 and the end plate 43 in the bellows body 41. (Corresponding to a spring). A stopper member 45 is provided on the end plate 43 side of the bellows body 41, and a stopper surface portion 45a of the stopper member 45 and a stopper surface portion 42 of the end plate 42 are provided. By contact with a, the bellows device 40 A large amount of shrinkage is specified.

An adjusting screw member 46 is screw-engaged with the bellows housing case 39. The adjusting screw member 46 is formed by a ball 47 and an end plate 4 arranged at the axis of the adjusting screw member 46. One end of the bellows device 40 is held by a spherical joint structure formed by a spherical recess 42b formed in the axial center portion (bellows center) of the stopper surface portion 42a. That is, the bellows device 40 and the bellows housing case 39 are spherically connected by the spherical joint structure via the adjusting screw member 46.

The bellows device 40 is directly connected to the ball valve body 37 in a spherical joint manner at a spherical recess 43 a formed in the axial center portion (bellows center) of the end plate 43. The expansion and contraction of the closing device 40 is transmitted to the ball valve element 37 as an axial force.

The bellows storage case 39 communicates with the suction port side passageway 33, and the bellows device 40 is connected to the suction pressure introduced into the bellows storage case 39 from the suction port side passageway 33 by the bellows. Expands and contracts according to the pressure difference from the internal pressure.

The other end (upper end) of the valve housing 31 is formed with a fitting hole 48 that passes through the center of the valve housing 31 in the axial direction. A discharge pressure introducing hollow tube 49 is fitted in the fitting hole 48 so as to be slidable in the axial direction. One end (lower end) of the discharge pressure introducing hollow tubular body 49 is joined to the ball valve body 37 by welding or the like. The other end (upper end) of the discharge pressure introducing hollow tube 49 is located in the fitting hole 48 and forms an inlet 49 c for the discharge pressure Pd of the compressor 1. The discharge pressure introducing hollow tube 49 is expanded at the joint (lower end) with the ball valve body 37, and the outer diameter D a of the discharge pressure introducing hollow tube 49 and the discharge pressure is being introduced. The effective diameter Db of the pressure receiving surface portion 37a of the pressure exerted on the ball valve body 37 from the hollow tube body 49 is equal to each other.

A compression coil spring 50 that urges the ball valve body 37 in the valve opening direction is provided between the enlarged diameter portion 49 a of the discharge pressure introduction hollow tubular body 49 and the valve housing 31 (in the claims). (Corresponding to the valve urging means).

The spring load of the compression coil spring 50 is such that when the ball valve element 37 is opened, the ball valve element 37 and the bellows device 40 rattle due to vibration during operation of the compressor 1. It is set to a value that does not exist.

As shown in FIG. 1, the control valve 30 having the above-described configuration includes a compressor housing Crankcase side passageway 3 and annular groove 35 communicate with crankcase 3 via crankcase pressure passageway 2, and suction port side passageway 33 and annular shape. The circumferential groove 36 communicates with the suction port 14 through the suction pressure passage 25, and the fitting hole 48 communicates with the discharge port 15 through the discharge pressure passage 26.

The crank chamber pressure passage 24, the suction pressure passage 25, and the discharge pressure passage 26 are pressure passages formed inside the compressor housing 2.

Next, the operation of the control valve 30 having the above configuration will be described.

The suction pressure P s of the compressor 1 passes from the suction port 14 through the suction pressure passage 25 to the annular circumferential groove 36, the suction port side passage 33, and furthermore, the bellows storage case 3 9 Inside, acting on the bellows device 40. Accordingly, the bellows device 40 expands and contracts according to the differential pressure between the suction pressure P s of the compressor 1 and the bellows internal pressure, and piles on the spring force of the compression coil spring 44 as the suction pressure P s increases. Shrink. The ball valve element 37 is opened by the discharge pressure Pd introduced by the discharge pressure introduction hollow pipe 49 acting on the pressure receiving surface 37 a and the spring force of the compression coil spring 50. Since the valve is biased in the valve direction, the valve is opened by contraction of the bellows device 40 due to an increase in the suction pressure Ps.

Assuming that the discharge pressure Pd acting as a correction pressure on the pressure-receiving surface 37a is constant, the ball valve element 37 has a valve opening force due to the suction pressure Ps acting on the bellows device 40 and the compression coil spring 44 spring. Opening / closing is driven by an equilibrium relationship with the valve closing force due to the force.

Therefore, if the suction pressure P s is equal to or lower than the control valve set pressure (reference set pressure P ss) determined by the set load of the compression coil spring 44, the ball valve element 37 is actuated by the spring force of the compression coil spring 44. The valve moves to close and seats on the valve seat 38 to close the valve. As a result, the supply of the suction pressure Ps to the crankcase 3 is stopped, the crankcase pressure Pc increases, and the compressor 1 enters the unload operation state.

On the other hand, when the suction pressure P s exceeds the control valve set pressure (reference set pressure P ss), the ball valve element 37 moves to open against the spring force of the compression coil spring 44, and the valve seat moves. Open the valve away from part 38. As a result, the suction pressure Ps is supplied to the crank chamber 3, the crank chamber pressure Pc becomes the same pressure as the suction pressure Ps, and the compressor 1 enters the full load operation state. As described above, when the discharge pressure Pd acting as the correction pressure on the pressure receiving surface portion 37a is fixed, that is, when the high pressure correction is not performed, the compressor 1 is moved by a broken line in FIG. As shown by, the displacement control operation is performed in which the suction pressure Ps is constant at the reference set pressure Pss.

The discharge pressure P d of the compressor 1 introduced into the discharge pressure introducing hollow pipe 49 directly acts as a correction pressure on the pressure receiving surface 37 a of the ball valve element 37, and the effective area of the pressure receiving surface 37 a Let A h be the valve opening force of A h · P d applied to the ball valve element 37. The discharge pressure Pd of the compressor 1 also acts on the inlet port 49 b of the discharge pressure introducing hollow pipe 49 slidably fitted in the fitting hole 48. However, since the outer diameter D a of the discharge pressure introducing hollow tube 49 is equal to the effective diameter D b of the pressure receiving surface portion 37 a of the ball valve body 37, the discharge pressure introducing hollow tube 49 is used. The discharge pressure Pd of the compressor 1 acting on the end face 49b of the compressor 1 is canceled.

Since the valve opening force due to AhPd that is correlated to the discharge pressure Pd acts on the ball valve element 37, the reference set pressure Pss is set in a balanced state at the reference discharge pressure Pds. When the discharge pressure P d decreases (discharge pressure P d <reference discharge pressure P ds), the suction pressure P s required to open the valve increases, and the discharge pressure P d increases (discharge pressure P d). The pressure P ds) reduces the suction pressure P s required to open the valve.

That is, when the discharge pressure P d decreases to P d ′, the valve opening force decreases by A h (P d −P d ′), and the valve opening force and the effective pressure receiving area A d of the bellows device 40 are reduced. From this ratio, a pressure characteristic is obtained in which the valve opening pressure rises according to Ah (Pd-Pd,) ZAd.

This is expressed by the following equation. By selecting the effective diameter of the discharge pressure introduction hollow tube 49 that determines the effective area Ah of the pressure receiving surface portion 37a, the desired high pressure influence characteristic can be obtained.

P s = P s s-A h (P d-P d s) / A d

As a result, as shown by the solid line in FIG. 3, a control characteristic is obtained in which the suction pressure Ps decreases in proportion to the increase in the discharge pressure Pd, and the discharge pressure Pd correlated with the system load characteristic is obtained. Thereby, the control characteristics of the displacement control compressor can be matched.

This means that in the refrigerant circuit system, the evaporation load and the condensation load are in a proportional relationship. In that, the evaporation load is proportional to the amount of circulating refrigerant, and the pressure loss in the evaporator is proportional to the amount of circulating refrigerant.

Also, since the ball valve element 37 is directly connected to the bellows device 40 and the ball valve element 37 acts as an automatic centripetal ball of a spherical joint between the valve element and the pressure response device, a special automatic centripetal ball or the like is used. The driving force of the bellows device 40 acts on the ball valve element 37 as an axial force without any need. Specific configuration of control valve for variable displacement compressor according to second preferred embodiment of the present invention Next, a control valve for variable displacement compressor according to the second embodiment of the present invention will be described with reference to FIG. Will be explained.

FIG. 4 shows a second embodiment of the control valve for a variable displacement compressor according to the present invention. In FIG. 4, parts corresponding to those in FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and description thereof will be omitted.

In the second embodiment, a guide cylinder 52 is inserted and fixed in a hole 51 corresponding to the fitting hole (48) of the first embodiment, and discharge is performed on an outer peripheral portion of the guide cylinder 52. The pressure introducing hollow tube 49 is movably fitted.

Also in the second embodiment, the discharge pressure Pd of the compressor 1 introduced into the discharge pressure introducing hollow pipe body 49 acts directly as a correction pressure on the pressure receiving surface 37a of the ball valve body 37, The same operation and effect as those of the first embodiment can be obtained, and the control valve characteristics at the time of actual operation can be made the characteristics related to the discharge pressure Pd.

In the second embodiment, since the discharge pressure Pd of the compressor 1 does not act on the end face 49a of the discharge pressure introducing hollow tube 49, the discharge pressure introducing hollow tube 49 There is no need to match the effective diameter with the outer diameter.

In the second embodiment as well, the ball valve element 37 is directly connected to the bellows device 40, and the ball valve element 37 acts as an automatic centripetal ball of the spherical joint between the valve element and the pressure response device. The driving force of the bellows device 40 acts on the pawl valve 37 as an axial force without requiring a special automatic centripetal ball or the like.

In any of the first and second embodiments described above, the pressure responsive device has a closed structure. Although the bellows device 40 was used, the pressure responsive device is not limited to the bellows device 40 but may be a diaphragm device, etc., for a variable displacement compressor in which the pressure responsive device is constituted by a diaphragm device. An embodiment applied to a control valve will be described below as a third embodiment. Specific Configuration of Control Valve for Variable Displacement Compressor According to Third Preferred Embodiment of the Invention Next, a control valve for a variable displacement compressor according to the third embodiment of the present invention will be described with reference to FIG. Will be explained.

FIG. 5 shows a third embodiment of the capacity control valve according to the present invention. In FIG. 5, parts corresponding to those in FIG. 2 are given the same reference numerals as those in FIG. 2, and description thereof is omitted.

The diaphragm device 60 includes a dish-shaped upper lid 61 crimped to the lower end of the valve housing 31, a dish-shaped lower lid 6 3 joined to the upper lid 61 with the diaphragm 62 interposed therebetween, and a lower lid. The spring box 64 includes a cylindrical spring box 64 that is swaged to the spring box 63, and an adjusting screw 65 that is threadedly engaged with the spring box 64.

The diaphragm 62 defines a diaphragm chamber 66 on the valve housing 31 side and a sealed chamber 67 on the spring box 64 side, and the holder 6 for the ball valve element 37 on the diaphragm chamber 66 side. Connected to 8.

A contact 69, a ball 70, and a spring receiving member 71 are sequentially provided on the closed chamber 67 side of the diaphragm 62, and a diaphragm is provided between the spring receiving member 71 and the adjusting screw 65. A compression coil spring 72 is provided to urge the ball valve element 37 in the valve closing direction (upward) via the element 62.

The diaphragm chamber 66 communicates with the valve chamber 34, and is provided with a suction pressure Ps guided to the valve chamber 34.

Also in the third embodiment, the configuration of the discharge pressure introducing hollow tubular body 49 and the like is the same as that of the first embodiment, so that the third embodiment has the same operation and effect as the first embodiment. can get.

Further, the ball valve element 37 is directly connected to the diaphragm device 60 via the holding body 68, and in this case also, the ball valve element 37 is connected to the spherical joint between the valve element and the pressure response device. Since it acts as a dynamic centripetal ball, the driving force of the bellows device 40 acts favorably on the ball valve element 37 as an axial force without requiring a special automatic centripetal ball or the like. In each of the embodiments described above, one end (lower end) of the discharge pressure introducing hollow tube 49 is joined to the ball valve body 37 by welding or the like, but the urging force of the compression coil spring 50 is used. Accordingly, one end (lower end) of the discharge pressure introducing hollow tubular body 49 may be pressed against the ball valve body 37. Industrial applicability

As is clear from the first to third embodiments described above, according to the control valve for a variable displacement compressor of the present invention, the discharge pressure of the compressor is controlled by the discharge pressure introducing hollow tube. Thus, the high pressure influence characteristic (discharge pressure influence characteristic) corresponding to the compressor discharge pressure is set, which acts directly on the ball valve body and correlates with the system load characteristic. In this case, an arbitrary high pressure influence characteristic can be obtained by setting the effective diameter of the discharge pressure introducing hollow tube, and the high pressure influence characteristic can be set with a high degree of freedom by selecting the effective diameter of the discharge pressure introducing hollow tube.

In addition, since the discharge pressure of the compressor is directly applied to the ball valve by the discharge pressure introducing hollow tube, the number of parts and assembly man-hours can be reduced compared to the conventional one, and it is directly incorporated into the compressor housing. In this case, the structure of the passage for guiding the suction pressure and the discharge pressure to each part of the displacement control valve is not complicated, and the degree of freedom of the arrangement position in the compressor housing is not limited.

In addition, since the ball valve element is directly connected to the pressure response device and the ball valve element acts as an automatic centripetal ball of the spherical joint between the valve element and pressure response device, a special automatic centripetal ball is required. Without this, the driving force of the pressure responsive device acts satisfactorily as an axial force on the ball valve body, so that the number of parts and the number of assembly steps can be reduced. According to the control valve for a variable displacement compressor of the present invention, the end face of the discharge pressure introduction hollow tube body slidably fitted in the fitting hole is also provided on the end face on the discharge pressure introduction port side. Although the discharge pressure acts, the outer diameter of the discharge pressure introduction hollow tube is equal to the effective diameter of the pressure receiving surface of the ball valve, so it acts on the end face of the discharge pressure introduction hollow tube at the discharge pressure introduction port side. Yes The discharge pressure of the compressor is canceled, and the required high pressure influence characteristics can be obtained.

Further, according to the control valve for a variable displacement compressor of the present invention, the discharge pressure introducing hollow tubular body is provided. The discharge pressure of the compressor does not act on the end face of the hollow pipe, and the required high pressure influence characteristics can be obtained without matching the effective diameter and the outer diameter of the discharge pressure introducing hollow tube.

Further, according to the control valve for a variable displacement compressor of the present invention, the ball valve is biased by the urging force of the valve urging means for urging the ball valve in the valve opening direction via the discharge pressure introducing hollow pipe. The vibration resistance of the body and pressure response device is improved, and a quiet and stable capacity control operation can be obtained.

Claims

The scope of the claims

1. A valve housing having a communication passage communicating the suction port of the compressor with the crank chamber;

A ball valve body provided in the valve housing to open and close the communication path; and a spring for biasing the ball valve body in a valve closing direction;

A pressure responsive device that is directly connected to the ball valve body as the automatic centripetal ball as the automatic centripetal ball, is driven by a suction pressure of a compressor, and drives the ball valve body in a valve opening direction;

The ball valve is slidably fitted to the valve housing, is joined at one end to the ball valve body, has an inlet for the discharge pressure of the compressor at the other end, and controls the discharge pressure of the compressor through an internal passage. And a discharge pressure introducing hollow tubular body acting as a force in a valve opening direction on a back surface of the body.

2. The control valve for a variable displacement compressor according to claim 1, wherein the hollow pipe is slidably fitted in a fitting hole formed in the valve housing during the discharge pressure introduction. A control valve for a variable displacement compressor, wherein a dimension and an effective diameter of a pressure receiving surface portion for exerting a discharge pressure of the compressor on the ball valve body are equal.

3. The control valve for a variable displacement compressor according to claim 1, wherein, during the introduction of the discharge pressure, the hollow pipe is slidably fitted to an outer peripheral portion of a guide cylinder fixed to the valve housing. A control valve for a variable displacement compressor.

4. The control valve for a variable displacement compressor according to any one of claims 1 to 3, further comprising a valve body for urging the ball valve body in a valve opening direction via the discharge pressure introducing hollow pipe body. A control valve for a variable displacement compressor, further comprising a biasing means.