JP4572272B2 - Control valve for variable capacity compressor - Google Patents

Description

  The present invention relates to a control valve for a variable capacity compressor, and more particularly to a control valve for a variable capacity compressor that controls a refrigerant discharged from the variable capacity compressor at a constant flow rate.

  The compressor used to compress the refrigerant in the refrigeration cycle of the air conditioner for automobiles has a capacity of refrigerant (discharge) in order to obtain an appropriate cooling capacity without being restricted by the rotational speed of the engine that is the driving source. A variable capacity compressor capable of changing the amount) is used. In such a variable capacity compressor, a piston that reciprocates in parallel with the rotation shaft is connected to a swing plate (swash plate) attached to a rotary shaft that is driven to rotate by an engine, and the swing plate of the swing plate is placed in the crank chamber. The stroke of the piston is changed by rotating while changing the inclination angle, so that the capacity of the compressor, that is, the discharge amount of the refrigerant is changed.

  In order to change the tilt angle of the swing plate, a part of the compressed refrigerant is introduced into the sealed crank chamber, and the pressure in the crank chamber is changed, so that the piston is connected to both sides of the piston connected to the swing plate. The inclination angle of the rocking plate is continuously changed by changing the balance of the applied pressure.

  In general, the pressure in the crank chamber is changed by controlling the control valve for the variable capacity compressor provided in the passage communicating the discharge chamber and the crank chamber so as to communicate or close. Here, when the control valve for the variable capacity compressor is set to a predetermined valve lift and the engine speed increases, the pressure introduced from the discharge chamber into the crank chamber increases, and the swing plate rotates. By approaching an inclination angle perpendicular to the axis, the capacity of the refrigerant that can be compressed is controlled to be small. On the other hand, when the rotational speed is reduced, the pressure introduced into the crank chamber is reduced so that the capacity of the refrigerant that can be compressed is increased. In this way, the variable capacity compressor is controlled so that the capacity of the discharged refrigerant does not change regardless of the engine speed.

  As a method of controlling the capacity of the variable capacity compressor by the control valve for the variable capacity compressor, generally, the control is performed so that the suction pressure Ps in the suction chamber is kept constant, the suction pressure Ps in the suction chamber and the discharge in the discharge chamber. There are known devices that control the pressure difference with the pressure Pd to be kept constant, but others that control the flow rate of the refrigerant discharged from the variable capacity compressor to be constant. (For example, refer to Patent Document 1).

  According to the control valve for a variable capacity compressor described in Patent Document 1, the flow rate of the refrigerant sucked into the suction chamber is indirectly grasped by detecting a differential pressure between two pressure monitoring points with a sensor, The control valve for the variable capacity compressor controls the flow rate of the refrigerant introduced from the discharge chamber into the crank chamber so that the suction flow rate becomes constant, thereby controlling the flow rate of the refrigerant discharged from the compressor to be constant. Has been.

On the other hand, there is also known a variable displacement compressor control valve that does not require a sensor for detecting a differential pressure between two pressure monitoring points (see, for example, Patent Document 2). The control valve for the variable capacity compressor includes a first control valve that controls the flow rate of the refrigerant flowing from the discharge chamber of the variable capacity compressor to the refrigerant outlet of the variable capacity compressor, and a difference between before and after the first control valve. The first control valve detects the pressure by the diaphragm and controls the flow rate of the refrigerant flowing from the discharge chamber to the crank chamber of the variable capacity compressor based on the differential pressure to change the discharge capacity of the variable capacity compressor. A second control valve for controlling the flow rate of the flowing refrigerant to be constant and a solenoid unit for setting the flow rate of the refrigerant to be flown by the first control valve are provided on the same axis. According to this variable displacement compressor control valve, the first control valve constitutes a variable orifice in which the passage area of the refrigerant passage is set by the solenoid portion in accordance with a change in external conditions, and the second control valve The pressure in the crank chamber is controlled so that the differential pressure before and after the variable orifice is sensed and the differential pressure becomes a predetermined value. As a result, the differential pressure before and after the variable orifice set to a certain passage area is held at a predetermined value, whereby the flow rate of the refrigerant discharged from the variable capacity compressor is controlled to be constant. .
JP 2001-107854 A (paragraph numbers [0035] to [0036], FIG. 3) JP 2004-116349 A (paragraph numbers [0102] to [0108], FIG. 12)

  However, the control valve for a variable capacity compressor described in Patent Document 2 is a refrigerant having a discharge pressure Pdh discharged from the discharge chamber between the first control valve and the second control valve arranged on the same axis. Since the refrigerant having the discharge pressure Pdl is derived from the first control valve and the refrigerant having the controlled crank chamber pressure Pc is derived from the second control valve, the first control valve The second control valve that is to be operated only by the differential pressure before and after the valve (Pdh−Pdl) is affected by the discharge pressure Pdh that is the pressure before and after that and the pressure Pc of the crank chamber. In order to solve the problem, a complicated pressure canceling structure must be provided, and the structure becomes complicated.

  In addition, the diaphragm for sensing the differential pressure before and after the first control valve is disposed on the outer periphery of a cylindrical body, one end of which forms the valve seat of the first control valve and is formed integrally with the body. Since the space between the pressure Pdh and the space of the discharge pressure Pdl is sealed and guided by the cylindrical body so as to be displaceable in the axial direction, complicated processing for forming the cylindrical body in the body is possible. There was a problem that it was necessary.

  The present invention has been made in view of these points, and provides a control valve for a variable displacement compressor having a simplified structure without the second control valve being affected by the pressure before and after the second control valve. Objective.

  In the present invention, in order to solve the above problem, a first control valve for controlling the flow rate of the refrigerant flowing from the discharge chamber of the variable capacity compressor to the refrigerant outlet of the variable capacity compressor, and before and after the first control valve The flow rate of the refrigerant flowing from the discharge chamber to the crank chamber of the variable capacity compressor is controlled based on the differential pressure of the variable capacity compressor, and the discharge capacity of the variable capacity compressor is changed to change the refrigerant flowing through the first control valve. In the control valve for a variable capacity compressor, comprising: a second control valve that controls the flow rate to be constant; and a solenoid unit that sets a flow rate of the refrigerant that the first control valve attempts to flow. The valve, the first control valve, and the solenoid unit are arranged on the same axis in this order, and the first control valve is provided on the second control valve side and is supplied from the discharge chamber. The first port for introducing the solenoid and the solenoid part side And a second port for leading the refrigerant to the refrigerant outlet, a donut-shaped diaphragm arranged to block a refrigerant passage between the first port and the second port, and fixed to the inner peripheral end of the diaphragm The first valve seat, and a first valve body disposed on the upstream side of the first valve seat so as to be freely contactable and separable from the first valve seat, wherein the second control valve is the first control valve. A third port that is provided on the axis opposite to the first port for introducing the refrigerant from the discharge chamber, and a fourth port that is provided on the first control valve side and leads the refrigerant to the crank chamber; A second valve seat provided in the third port, and an end opposite to the second valve seat that is slidably supported downstream of the second valve seat and that faces the second valve seat A cylindrical second valve body exposed at one port, and the first port of the first control valve The displacement of the diaphragm in the axial direction according to the differential pressure at the second port is transmitted to the second valve body of the second control valve via a differential pressure transmission member. A control valve for a variable displacement compressor is provided.

  According to such a control valve for a variable capacity compressor, the first control valve and the second control valve introduce the refrigerant from the discharge chamber into the second port of the second control valve. A fourth port was provided on both ends of the valve body in the axial direction and communicated from the second control valve to the crank chamber. As a result, the second control valve can eliminate the influence of the discharge pressure of the refrigerant introduced from the discharge chamber and the pressure of the refrigerant supplied to the crank chamber, so that the controllability can be improved. Since there is no need to provide a mechanism for canceling the pressure to the crank chamber, the structure can be simplified.

  The control valve for a variable capacity compressor according to the present invention has a structure in which the second control valve for controlling the discharge pressure to the pressure to the crank chamber is not affected by the discharge pressure and the pressure to the crank chamber. Since the second control valve can be controlled only by the differential pressure before and after the control valve, the controllability can be improved, and a mechanism for canceling the discharge pressure and the pressure to the crank chamber is unnecessary. Can be simplified, and the cost can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a central longitudinal sectional view showing a configuration of a control valve for a variable capacity compressor according to the present invention in a non-energized state, FIG. 2 is a perspective view showing members around a first control valve, and FIG. The holder, (B) is the differential pressure transmission member, (C) is the first valve body, and FIG. 3 is a central longitudinal sectional view showing the configuration of the control valve for the variable capacity compressor according to the present invention in an energized state.

The variable displacement compressor control valve 10 includes a first control valve 10A, a second control valve 10B, and a solenoid unit 10C, and is disposed on the same axis.
The first control valve 10A and the second control valve 10B have a first body 11 and a second body 12 press-fitted thereto. The first body 11 and the second body 12 are connected to the discharge chamber of the variable capacity compressor when the variable capacity compressor capacity control valve is attached to the variable capacity compressor, and the first control valve 10A. A port 13 for introducing a refrigerant having a discharge pressure Pdh to the refrigerant, a port 14 communicating with a refrigerant outlet of the variable capacity compressor and deriving a refrigerant having a discharge pressure Pdl from the first control valve 10A, and a discharge chamber of the variable capacity compressor And a port 15 for introducing a refrigerant having a discharge pressure Pdh2 to the second control valve 10B, and a port 16 for communicating a refrigerant having a pressure Pc from the second control valve 10B and communicating with a crank chamber of the variable capacity compressor. And are provided. This displacement control valve for a variable displacement compressor is configured so that both the port 13 of the discharge pressure Pdh and the port 15 of the discharge pressure Pdh2 are in direct communication with the discharge chamber when mounted on the variable displacement compressor. Preferably, the port 13 with the discharge pressure Pdh communicates directly with the discharge chamber, and the port 15 with the discharge pressure Pdh2 communicates with the outlet of the oil separator provided on the downstream side of the discharge chamber. The present invention is preferably applied to a variable capacity compressor configured as described above. Thus, the second control valve 10B can return the lubricating oil for the variable capacity compressor contained in the refrigerant in a large amount to the crank chamber while controlling the pressure Pc of the crank chamber.

  The first control valve 10A has a passage formed in the axial direction so as to connect the port 13 of the discharge pressure Pdh and the port 14 of the discharge pressure Pdl in the first body 11, and the first valve is in the passage. A seat 17 and a first valve body 18 are arranged. The first valve body 18 is disposed on the upstream side of the first valve seat 17 so as to be able to contact with and separate from the first valve seat 17. That is, as shown in FIG. 2C, the first valve body 18 is integrally formed with three guides 19 that extend into the valve hole and are evenly arranged in the circumferential direction. It comes in sliding contact with the inner wall of the valve hole. As a result, the first valve body 18 can be contacted and separated in the axial direction with respect to the first valve seat 17 while maintaining concentricity with the first valve seat 17.

  The first valve seat 17 is centered by the diaphragm 20 in the passage in which it is disposed. That is, the diaphragm 20 is a donut-shaped polyimide resin sheet having an open central portion, and the outer peripheral end thereof is held by press-fitting the second body 12 into the first body 11, and the inner peripheral end is The first valve seat 17 is press-fitted into the transmission member 21 and is held. Thereby, the diaphragm 20 receives a differential pressure between the discharge pressure Pdh from the port 13 and the discharge pressure Pdl at the port 14, and is displaced in the axial direction according to the differential pressure, and the displacement is applied to the first valve seat 17. It is transmitted to the fitted differential pressure transmission member 21. The displacement in the axial direction is restricted by contacting the first valve seat 17 with the stepped portion provided in the first body 11 on the solenoid portion 10C side, and the second control valve 10B side. Is regulated by the differential pressure transmission member 21 being brought into contact with the second body 12.

  As shown in FIG. 2B, the differential pressure transmission member 21 includes a ring-shaped base portion 22 fitted to the first valve seat 17, a locking portion 24 having a hole 23 in the center, a base It has the connection part 25 which connects the part 22 and the latching | locking part 24, and these are integrally formed. The connection part 25 is provided in three places equally arrange | positioned in the circumferential direction, and the space between them becomes a channel | path of the refrigerant | coolant which flows through 10 A of 1st control valves.

  In addition, a spring holder 26 fitted to the second body 12 is provided on the upper portion of the first valve body 18 in the figure. The spring holder 26 has a base portion 28 having a hole 27 drilled in accordance with these shapes so as not to interfere with the locking portion 24 and the connecting portion 25 of the differential pressure transmission member 21 at the center, and downward in the figure. There are three guides 29 extending, and these are integrally formed. The guides 29 are equally arranged in the circumferential direction, and the space between them is a passage for the refrigerant flowing through the first control valve 10A. In addition, the guide 29 is a guide when the first valve body 18 moves back and forth in the axial direction because the cylindrical extension 30 extending in the upper part of the figure of the first valve body 18 is located inside. Yes.

  Further, in the first control valve 10A, the first valve seat 17 is urged in the valve closing direction by a spring 31 disposed in a space communicating with the port 14 of the discharge pressure Pdl, and the first valve body 18 is The spring 32 is urged in the valve closing direction by a spring 32 disposed in the spring holder 26.

  The second control valve 10B is disposed on the downstream side of the second valve seat 40, the second valve seat 40 being press-fitted into the axial port 15 formed at the tip of the second body 12, and the second control valve 10B. A cylindrical second valve body 41 is supported by the body 12 so as to be able to contact with and separate from the second valve seat 40. The end of the second valve body 41 opposite to the side facing the second valve seat 40 is exposed in the chamber of the discharge pressure Pdh, and the tip thereof is provided in the locking portion 24 of the differential pressure transmission member 21. A spring receiving member 42 is fitted in the hole 23. A spring 43 is disposed between the spring receiving member 42 and the first valve body 18, and urges the spring receiving member 42 to always abut against the locking portion 24 of the differential pressure transmission member 21.

  The solenoid part 10 </ b> C has a core 50 formed integrally with the first body 11, and is fitted into the opening of the bottomed sleeve 51. In the bottomed sleeve 51, a plunger 52, a shaft 53 extending through the core 50 in the axial direction and fixed to the plunger 52, and a bearing portion 54 disposed at the lower end of the shaft 53 in the figure. A spring 55 disposed between the core 50 and the plunger 52, and a spring 56 disposed between the plunger 52 and the bearing portion 54. The shaft 53 is held by the core 50 and the bearing portion 54 so as to be able to advance and retreat in the axial direction, and the upper end portion in the drawing is located inside the guide 19 of the first valve body 18, and when the solenoid portion 10 </ b> C is energized, Abutting on the valve body 18, the first valve body 18 is urged in the valve opening direction of the first control valve 10 </ b> A. On the outer periphery of the bottomed sleeve 51, yokes 57, 58 and a coil 59 are arranged.

  On the outside of the first body 11 and the second body 12, an O-ring 60 that seals between the port 13 and the port 14, an O-ring 61 that seals between the port 13 and the port 16, a port 16 and the port 15 An O-ring 62 that seals between the two and a packing 63 that seals between the port 14 and the atmosphere are provided. On the outer peripheral portion of the yoke 57, there is provided a threaded portion 64 necessary for mounting the variable displacement compressor control valve 10 to the variable displacement compressor.

  In the variable displacement compressor control valve 10 configured as described above, when the variable displacement compressor is driven to rotate by receiving the driving force of the engine, the variable displacement compressor sucks and compresses the refrigerant from the suction chamber. Then, the compressed refrigerant is discharged into the discharge chamber.

  At this time, as shown in FIG. 1, when the solenoid unit 10C is in a non-energized state, the first control valve 10A is in a fully closed state and the second control valve 10B is in a fully open state. Accordingly, all of the refrigerant discharged into the discharge chamber is introduced into the crank chamber via the second control valve 10B, so that the variable capacity compressor is in a minimum capacity operation state.

  When the solenoid unit 10C is supplied with a predetermined control current, as shown in FIG. 3, the shaft 53 pushes up the first valve body 18 upward in the drawing, and the first valve body 18 is a solenoid unit corresponding to the current value. It stops at a position where the urging force of 10C and the urging force of the spring 32 opposed to this force are balanced. The stop position of the first valve body 18 does not change until the current value of the control current changes. When the first valve body 18 is lifted from the first valve seat 17, the first control valve 10 </ b> A sets a predetermined passage area with respect to the refrigerant passage, and the discharge pressure Pdh introduced into the port 13. The refrigerant flows through the refrigerant passage having the predetermined passage area, and the refrigerant having the discharge pressure Pdl is led out from the port 14.

  At this time, a predetermined differential pressure (PdH−PdL = ΔP) is generated before and after the first control valve 10 </ b> A, and the differential pressure ΔP is detected by the diaphragm 20. On the other hand, the first valve seat 17, which has been pushed down to the lower limit position in the figure by the refrigerant discharge pressure Pdh introduced into the port 13, is separated from the first valve body 18 by the lift of the first valve body 18. 20 is displaced to a position corresponding to the differential pressure ΔP. The displacement is transmitted to the second valve body 41 of the second control valve 10B via the differential pressure transmission member 21 fixed to the first valve seat 17. The second control valve 10B is controlled to a valve lift corresponding to the differential pressure ΔP, and the refrigerant of the pressure Pc whose flow rate is controlled by the second control valve 10B is supplied from the port 16 to the crank chamber, and the variable capacity compressor Is in an operating state with a capacity corresponding to the current value of the control current.

  Here, when the flow rate of the refrigerant flowing through the first control valve 10A increases and the differential pressure ΔP increases, the diaphragm 20 is displaced downward in the figure, and the first valve seat 17 is pushed down in the figure. This displacement is transmitted to the second valve body 41 via the differential pressure transmission member 21, and the valve lift of the second control valve 10B is increased. As a result, the variable capacity compressor is controlled so as to decrease its capacity, and thus is controlled so as to decrease the flow rate of the refrigerant flowing through the first control valve 10A. Conversely, when the flow rate of the refrigerant flowing through the first control valve 10A decreases and the differential pressure ΔP decreases, the valve lift of the second control valve 10B decreases, and the variable capacity compressor controls to increase its capacity. Then, the flow rate of the refrigerant flowing through the first control valve 10A is controlled to increase.

  In this way, the variable displacement compressor control valve 10 has the passage area of the first control valve 10A set according to the current value of the control current supplied to the solenoid unit 10C. The diaphragm 20 senses the differential pressure ΔP generated before and after the control valve 10A and controls the second control valve 10B. Then, if the differential pressure ΔP changes from a predetermined value, the second control valve 10B is controlled so as to become the predetermined value, whereby the flow rate of the refrigerant flowing through the first control valve 10A is controlled to be constant. Will be.

  In the second control valve 10B, the second valve body 41 has a discharge pressure Pdh at one end in the valve closing direction and a discharge pressure Pdh2 substantially equal to the discharge pressure Pdh at the other end in the valve opening direction. Therefore, the influence of the high pressure can be ignored, and the pressure Pc is also received in the same pressure receiving area in both the valve closing direction and the valve opening direction, so the influence of the pressure Pc can be ignored. Therefore, the second control valve 10B is controlled solely by the differential pressure ΔP generated before and after the first control valve 10A without requiring a mechanism for canceling the discharge pressure Pdh2 and the pressure Pc. The variable displacement compressor control valve 10 can be made compact, and the controllability of the variable displacement compressor can be improved.

It is a center longitudinal cross-sectional view which shows the structure of the control valve for variable capacity compressors by this invention in a non-energized state. It is a perspective view which shows the member around the 1st control valve, Comprising: (A) is a spring holder, (B) is a differential pressure transmission member, (C) has shown the 1st valve body. It is a center longitudinal cross-sectional view which shows the structure of the control valve for variable capacity compressors by this invention in an electricity supply state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control valve for variable capacity compressor 10A 1st control valve 10B 2nd control valve 10C Solenoid part 11 1st body 12 2nd body 13 Port (Pdh)
14 ports (Pdl)
15 ports (Pdh2)
16 ports (Pc)
17 1st valve seat 18 1st valve body 19 Guide 20 Diaphragm 21 Differential pressure transmission member 22 Base part 23 Hole 24 Locking part 25 Connection part 26 Spring holder 27 Hole 28 Base part 29 Guide 30 Cylindrical extension parts 31 and 32 Spring 40 Second valve seat 41 Second valve body 42 Spring receiving member 43 Spring 50 Core 51 Bottomed sleeve 52 Plunger 53 Shaft 54 Bearing portion 55, 56 Spring 57, 58 Yoke 59 Coil 60, 61, 62 O-ring 63 Packing 64 Threaded part

Claims (5)

A first control valve for controlling a flow rate of a refrigerant flowing from a discharge chamber of the variable capacity compressor to a refrigerant outlet of the variable capacity compressor, and the discharge chamber from the discharge chamber based on a differential pressure before and after the first control valve. A second control valve that controls the flow rate of the refrigerant flowing by the first control valve to be constant by controlling the flow rate of the refrigerant flowing to the crank chamber of the variable displacement compressor and changing the discharge capacity of the variable displacement compressor. And a control valve for a variable capacity compressor comprising a solenoid unit that sets a flow rate of a refrigerant that the first control valve is to flow.
The second control valve, the first control valve, and the solenoid unit are arranged on the same axis in this order, and the first control valve is provided on the second control valve side, and A first port for introducing the refrigerant from the discharge chamber; a second port provided on the solenoid portion side for leading the refrigerant to the refrigerant outlet; and a refrigerant passage between the first port and the second port A donut-shaped diaphragm disposed so as to block the first valve seat, a first valve seat fixed to an inner peripheral end of the diaphragm, and a first valve disposed so as to be able to contact and separate upstream from the first valve seat The second control valve is provided on the opposite side of the first control valve on the axis thereof, the third port for introducing the refrigerant from the discharge chamber, and the first control A fourth port provided on the valve side for leading the refrigerant to the crank chamber; A second valve seat provided at the port, and an end opposite to the side facing the second valve seat, which is supported on the downstream side of the second valve seat so as to be able to come into contact with and separate from the second valve seat. A displacement of the diaphragm in the axial direction in accordance with a differential pressure at the first port and the second port of the first control valve is a differential pressure transmission. A control valve for a variable capacity compressor, wherein the control valve is transmitted to the second valve body of the second control valve via a member.   The first valve body of the first control valve is integrally formed with a plurality of guides extending into the valve hole of the first valve seat, and is held on the same axis as the first valve seat. 2. The control valve for a variable capacity compressor according to claim 1, wherein the control valve is in contact with and away from the first valve seat.   The first valve body of the first control valve is guided by a plurality of guides extending in an axial direction fixed to a body supporting the diaphragm and the second valve body, and is guided with respect to the first valve seat. 2. The control valve for a variable capacity compressor according to claim 1, wherein the control valve is in contact with or separated from the variable capacity compressor.   The differential pressure transmission member is configured such that one end in the axial direction sandwiches the inner peripheral end of the diaphragm together with the first valve seat, and the other end is engaged with the second valve body. The control valve for a variable displacement compressor according to claim 1. The solenoid portion has a shaft that drives the first valve body through a valve hole of the first valve seat, and the shaft abuts on the first valve body when energized, and the first valve body does not energize. 2. The control valve for a variable capacity compressor according to claim 1, wherein the control valve is separated from the valve body.

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