JP4173019B2 - Capacity control valve for variable capacity compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a capacity control valve for a variable capacity compressor, and more particularly to a capacity control valve for a variable capacity compressor for controlling a refrigerant discharge capacity of a variable capacity compressor used in a refrigeration cycle of a vehicle air conditioner.
[0002]
[Prior art]
In a vehicle air conditioner, in order to control the refrigeration capacity according to a load, it is a common practice to make the compressor capacity variable because the rotational speed of the engine that is the power source is not constant.
[0003]
As means for changing the capacity of the compressor, for example, a capacity control valve for a variable capacity compressor as described in Patent Document 1 is known. In such a capacity control valve for a variable capacity compressor, a valve for controlling the flow rate of the refrigerant supplied from the discharge chamber to the crank chamber is disposed in the refrigerant flow path that connects the discharge chamber of the variable capacity compressor and the crank chamber. The diaphragm that senses the suction pressure in the suction chamber of the variable capacity compressor and the valve section and controls the opening of the valve section, and the position at which the diaphragm starts to be displaced in the direction of the valve section can be freely set by an external electric signal. The solenoid part is arranged coaxially in this order.
[0004]
A shaft is disposed between the valve body of the valve portion and the diaphragm, and when the diaphragm is displaced according to the suction pressure of the suction chamber of the variable capacity compressor, the displacement of the diaphragm is transmitted to the valve body through the shaft. As a result, the valve portion is opened and closed. By opening and closing the valve portion, the flow rate of the refrigerant supplied from the discharge chamber to the crank chamber is controlled, and the pressure in the crank chamber is controlled. As a result, the stroke of the piston that sucks and compresses the refrigerant, that is, the refrigerant discharge capacity, is controlled so that the capacity of the compressor becomes constant even when the engine speed changes.
[0005]
[Patent Document 1]
JP 2001-349278 (paragraph numbers [0015] to [0020], FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in a conventional capacity control valve for a variable capacity compressor, a drive source such as a diaphragm or a solenoid part opens and closes the valve part by energizing the valve body of the valve part through the shaft, so that the assembly performance is improved. When the valve part and the shaft are configured separately from each other, when the valve element arranged so as to be able to contact and separate in the axial direction with respect to the valve seat is urged in the axial direction by the shaft, The body is tilted with respect to the axis and the lateral load is generated, and the body moves forward and backward. As a result , the valve body slides on the inner wall of the central opening that accommodates it and the valve part opens. However, there is a problem that the characteristics differ depending on the closing direction, that is, the characteristics of the hysteresis are large, and the valve body may be prevented from being completely closed due to the lateral displacement of the valve body.
[0007]
The present invention has been made in view of these points, and reduces the occurrence of lateral load on the valve body driven by the shaft to reduce hysteresis, and reduces the lateral displacement of the valve body to close the valve body. An object of the present invention is to provide a capacity control valve for a variable capacity compressor in which is completed.
[0008]
[Means for Solving the Problems]
In the present invention, in order to solve the above problems, a valve unit for controlling the flow rate of refrigerant supplied to the crank chamber from the discharge chamber of the variable capacity compressor, the driving force transmission for transmitting a driving force by the solenoid portion to the valve portion And a valve body of the valve portion receives the refrigerant from the discharge chamber in a direction away from the valve seat, and is arranged so as to receive a driving force in a direction of sitting on the valve seat from the driving force transmission member. have been, in the electromagnetic capacity control valve of which is to control the refrigerant discharge capacity of the variable capacity compressor, before Kiben body, contact the ball and the ball relative to the valve seat A hollow holder that is detachably held, and the holder is held in a cylindrical opening formed integrally with the valve seat so as to be movable back and forth in the axial direction, and the driving force transmission member is attached to the solenoid Valve inserted loosely from the end face The capacity control valve, characterized in that in contact with point contact with the ball held in the side is provided.
[0009]
According to such a capacity control valve for a variable capacity compressor, the driving force transmission member drives the valve body of the valve portion at a position where the ball held by the holder on the valve seat side rather than the end surface on the solenoid portion side is located. Like to do. As a result, the valve body driven by the driving force transmission member reduces the lateral load on the valve body that is generated when the valve body is driven by the driving force transmission member, and can reduce hysteresis in the opening / closing characteristics of the valve. Further, since the lateral displacement amount of the valve body is reduced, the valve body can be completely closed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a central sectional view showing the structure of a capacity control valve for a variable capacity compressor according to a first embodiment of the present invention.
[0011]
The capacity control valve for the variable capacity compressor is provided inside the upper body 1, one of which is connected to the discharge chamber of the variable capacity compressor and receives the refrigerant having the discharge pressure Pd, and the other is the crank of the variable capacity compressor. The ball 2 is disposed in a refrigerant flow path that communicates with the chamber and supplies a refrigerant having a pressure Pc to the crank chamber. A valve seat forming member 3 is press-fitted into the upper opening of the upper body 1. A strainer 4 is attached to cover the upper edge of the upper body 1. The valve seat forming member 3 is formed with a valve hole 5 at its intermediate portion so as to communicate with the spaces on the discharge chamber side and the crank chamber side, and the opening edge on the crank chamber side constitutes the valve seat. The ball 2 is arranged opposite to the valve hole 5. The ball 2 is held by a holder 6 disposed in a cylindrical opening integrally formed at a lower portion of the valve seat forming member 3 so as to be movable back and forth in the axial direction, and constitutes a valve body together with the holder 6. Then, the variable capacity compression in which the flow rate of the refrigerant supplied from the discharge chamber of the variable capacity compressor to the crank chamber is controlled by the valve seat at the opening edge of the valve hole 5 and the valve body composed of the ball 2 and the holder 6. This constitutes the valve part of the machine capacity control valve. The holder 6 is urged by a spring 7 in a direction in which the ball 2 is separated from the valve seat.
[0012]
A piston rod 9 having the same diameter as the valve hole 5 of the valve seat forming member 3 is disposed at the axial position of the upper body 1 so as to be able to advance and retract in the axial direction. One end of the piston rod 9 penetrates the holder 6 and contacts the ball 2, and the other end terminates in the central opening of the upper body 1.
[0013]
In this way, the ball 2 is held by the holder 6 so as to move integrally with the holder 6 to constitute a valve body, and one end of the piston rod 9 is in point contact with the ball 2 held on the side close to the valve seat. It is comprised so that it may contact | abut. By making the contact position of the piston rod 9 with the valve body not the holder 6 but the ball 2 that has passed through the holder 6, the valve body acts like Yajirobei. As a result, since the lateral movement of the valve body is suppressed, the valve body can move back and forth in the axial direction in a stable state with reduced lateral load. In addition, since the lateral load on the valve body generated during forward / backward movement is reduced, hysteresis is reduced in the opening / closing characteristics of the valve, and the lateral displacement of the valve body is suppressed, so that the valve body can be expected to be completely closed.
[0014]
The upper body 1 is screwed into the upper opening of the lower body 8 at an intermediate position thereof, and a fixed iron core 10 of a solenoid part is screwed to the lower end portion. The fixed iron core 10 has a central opening formed at its axial position, and the central opening communicates with the suction chamber of the variable capacity compressor through a communication hole formed from the periphery. The suction pressure Ps of the suction chamber is received at the end of the suction chamber.
[0015]
A sleeve 11 is disposed inside the lower body 8. A stopper 12 is fitted into the lower opening of the sleeve 11 in the figure, and a guide 13 is screwed into the central opening so as to close it. A fixed iron core 10 and a movable iron core 14 screwed to the upper body 1 are disposed in the sleeve 11. The movable iron core 14 has one end penetrating the fixed iron core 10 and supported by the central opening of the upper body 1, and the other end fixed to a shaft 15 supported by the central opening of the guide 13. Movement in the direction of the piston rod 9 is regulated by a retaining ring 16 fitted to the piston 15. Thereby, the movable iron core 14 can advance and retreat in the axial direction without contacting the sleeve 11. A spring 17 is disposed between the fixed iron core 10 and the movable iron core 14, and a spring 18 is disposed between the movable iron core 14 and the guide 13.
[0016]
An electromagnetic coil 19 and a yoke 20 are provided on the outer periphery of the sleeve 11, and together with the fixed iron core 10 and the movable iron core 14 constitute a solenoid unit.
When the displacement control valve is mounted inside the variable displacement compressor, the space between the portion that communicates with the discharge chamber and receives the discharge pressure Pd and the portion that communicates with the crank chamber and receives the pressure Pc. An O-ring 21 is provided around the upper body 1 for sealing. Further, the lower body 8 includes an O-ring 22 for sealing between a portion that receives the pressure Pc of the crank chamber and a portion that communicates with the suction chamber and receives the suction pressure Ps, and a portion that receives the suction pressure Ps. And an O-ring 23 for sealing between the air and the atmosphere.
[0017]
Here, the operation of the capacity control valve for the variable capacity compressor will be described together with the operation of the variable capacity compressor.
Inside the capacity control valve for the variable capacity compressor, the discharge pressure Pd of the refrigerant introduced from the discharge chamber is applied to the ball 2 from the upper side in the figure. On the other hand, the suction pressure Ps of the suction chamber is applied to the piston rod 9 in contact with the ball 2 from the lower side of the drawing through the clearance between the upper body 1 and the shaft 15. Since the piston rod 9 has the same diameter as the valve hole, the effective pressure receiving area of the discharge pressure Pd in the ball 2 and the pressure receiving area of the suction pressure Ps in the piston rod 9 are the same. Therefore, the ball 2 that controls the flow rate of the refrigerant flowing from the discharge chamber to the crank chamber constitutes a differential pressure valve that operates by feeling the differential pressure between the discharge pressure Pd and the suction pressure Ps.
[0018]
In such a capacity control valve for a variable capacity compressor, when the control current is not supplied to the electromagnetic coil 19 of the solenoid unit, the discharge pressure Pd pushes the ball 2 open, so that the ball 2 is fully opened. Thereby, in the variable capacity compressor, the pressure Pc in the crank chamber becomes a value close to the discharge pressure Pd, and in the refrigerant suction compression piston provided facing the crank chamber, the pressure difference between both surfaces is the largest. Get smaller. Therefore, the swing plate in the crank chamber that determines the stroke of the piston has an inclination angle that minimizes the stroke, and the variable capacity compressor operates with the minimum capacity.
[0019]
Further, when the maximum control current is supplied to the electromagnetic coil 19 of the solenoid unit, the movable iron core 14 is attracted to the fixed iron core 10 and moved upward in the figure, whereby the shaft 15 and the piston rod 9 are moved. When pushed up in the figure, the ball 2 is fully closed. At this time, since the crank chamber communicates with the suction chamber via the fixed orifice, the refrigerant in the crank chamber flows to the suction chamber via the orifice, and the crank chamber pressure Pc is close to the suction pressure Ps of the suction chamber. To fall. As a result, the pressure difference applied to both surfaces of the piston becomes the largest, and the swing plate has an inclination angle that maximizes the stroke of the piston, and the variable capacity compressor shifts to the maximum capacity operation.
[0020]
Here, when a normal control is performed in which a predetermined control current is supplied to the electromagnetic coil 19 of the solenoid unit, the movable iron core 14 is attracted to the fixed iron core 10 according to the magnitude of the control current. A force is generated to move a predetermined amount upward in the figure. This force becomes the set value of the displacement control valve for the variable displacement compressor that operates as a differential pressure valve. Therefore, the capacity control valve for the variable capacity compressor senses the differential pressure between the discharge pressure Pd and the suction pressure Ps, and discharges the differential pressure so as to maintain the differential pressure corresponding to the value set by the solenoid unit. The operation of controlling the flow rate of the refrigerant flowing from the chamber to the crank chamber is performed.
[0021]
At this time, since the valve body composed of the ball 2 and the holder 6 is driven by the piston rod 9 at a position close to the valve seat, the valve body can be stably opened and closed without generating a lateral load. Hysteresis can be reduced by reducing the sliding resistance generated with the valve seat forming member 3. In addition, since the ball 2 is not seated on the valve seat in a state where the valve body is laterally displaced, the open / close characteristics in the vicinity of the fully closed state are not disturbed, and the state can be shifted to the completely closed state.
[0022]
FIG. 2 is a central cross-sectional view showing the structure of a capacity control valve for a variable capacity compressor according to a second embodiment of the present invention. In FIG. 2, the same components as those of the displacement control valve for the variable displacement compressor shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0023]
The capacity control valve for a variable capacity compressor according to the second embodiment is a valve body having a tapered seating surface as compared with the capacity control valve for a variable capacity compressor according to the first embodiment. There are some differences. That is, the valve body 24 of this capacity control valve is integrally formed with a tip end portion having a tapered seating surface and a sliding portion that moves back and forth in the axial direction within the lower opening of the valve seat forming member 3. A concave recess 25 into which the piston rod 9 is loosely inserted is provided on the end surface of the sliding portion of the valve body 24 on the solenoid portion side, and the contact position with the piston rod 9 is more than the middle in the axial direction of the valve body 24. The bottom of the recess 25 is a position close to the seating surface of the tip. Thereby, the valve body 24 acts like Yajirobei, the lateral movement is suppressed, the lateral load is reduced, and the axial direction can be moved back and forth in a stable state. In addition, since the lateral load on the valve body generated during forward / backward movement is reduced, hysteresis is reduced in the opening / closing characteristics of the valve, and the lateral displacement of the valve body is suppressed, so that the valve body can be expected to be completely closed.
[0024]
In the above embodiment, an example of an electromagnetic variable displacement compressor displacement control valve that controls the pressure difference between the discharge pressure Pd of the discharge chamber and the suction pressure Ps of the suction chamber to be constant has been described. However, for example, the present invention can be applied to a displacement control valve for an electromagnetic variable displacement compressor that controls the diaphragm to receive the suction pressure Ps and keep the suction pressure Ps constant.
[0025]
【The invention's effect】
As described above, in the present invention, a concave recess is provided on the end surface of the valve body on the solenoid part side, and the contact position between the valve body and the shaft that drives the valve body is more than the end surface on the solenoid part side of the valve body. The position is set close to the seating side. Thereby, the lateral load to the valve body generated when the valve body is driven by the shaft is reduced, and the hysteresis in the opening / closing characteristics of the valve can be reduced. Further, since the lateral displacement amount of the valve body is reduced, the valve body can be completely closed.
[Brief description of the drawings]
FIG. 1 is a central sectional view showing a structure of a capacity control valve for a variable capacity compressor according to a first embodiment of the present invention.
FIG. 2 is a central sectional view showing the structure of a displacement control valve for a variable displacement compressor according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper body 2 Ball 3 Valve seat formation member 4 Strainer 5 Valve hole 6 Holder 7 Spring 8 Lower body 9 Piston rod 10 Fixed iron core 11 Sleeve 12 Stopper 13 Guide 14 Movable iron core 15 Shaft 16 Retaining ring 17, 18 Spring 19 Electromagnetic coil 20 Yoke 21, 22, 23 O-ring 24 Valve body 25 Recess

Claims (2)

A valve unit for controlling the flow rate of the refrigerant supplied to the crank chamber from the discharge chamber of the variable capacity compressor,
A driving force transmission member for transmitting a driving force by a solenoid portion to the valve portion;
The valve body of the valve portion receives the refrigerant from the discharge chamber in a direction away from the valve seat, and is arranged so as to receive a driving force from the driving force transmission member in a direction of sitting on the valve seat. In the electromagnetic capacity control valve for the variable capacity compressor, the refrigerant discharge capacity of the variable capacity compressor is controlled.
Before Kiben body, axially the ball and the ball to the valve seat and a hollow holder for separable freely held against the holder cylindrical opening which is formed integrally with the valve seat The driving force transmission member is loosely inserted into the holder from the end surface on the solenoid part side and is in contact with the ball held on the valve seat side by point contact. Capacity control valve for variable capacity compressor. A valve unit for controlling the flow rate of the refrigerant supplied from the discharge chamber of the variable capacity compressor to the crank chamber;
  A driving force transmitting member for transmitting a driving force by a solenoid portion to the valve portion;
  The valve body of the valve portion receives the refrigerant from the discharge chamber in a direction away from the valve seat, and is arranged to receive a driving force from the driving force transmission member in a direction of sitting on the valve seat. In the electromagnetic capacity control valve for the variable capacity compressor, the refrigerant discharge capacity of the variable capacity compressor is controlled.
  The valve body is held in a cylindrical opening formed integrally with the valve seat so as to be able to advance and retreat in a direction in which the valve body comes into contact with and separates from the valve seat. It has a concave recess having a bottom on the valve seat side, and the driving force transmission member is loosely inserted into the recess from the end surface on the solenoid part side and is in contact with the bottom of the recess by point contact. A capacity control valve for a variable capacity compressor.

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