Control valve for variable displacement compressor

Abstract

A control valve for a variable displacement compressor, where sliding resistance by movement of a valve is reduced as much as possible to stably and accurately regulate the rate of air flow, enabling a suction pressure corresponding to solenoid thrust to be maintained. The discharge pressure Pd of the compressor introduced into a pressure sensing section (40) applies urging force to a movement member (50), and a solenoid section (36) applies, in cooperation with the urging force, urging force to the movement member (50) depending on an input signal. The degree of opening of a valve body (56) provided at the movement member (50) is set according to the position of the movement member (50) to regulate the rate of air flow in a communication path for interconnecting a discharge pressure region of the compressor and a compressor inner chamber. The suction pressure Ps of the compressor is introduced into a control valve to apply urging force to the movement member (50), and communication between fluid having the discharge pressure Pd introduced into the pressure sensing section (40) and fluid having the suction pressure Ps introduced into the control valve is shut off.

Description

technical field [0001] The present invention relates to a variable displacement type having a pressure sensitive part, a solenoid part, and a valve part composed of a spool provided on a moving part, and the internal pressure of the compressor is adjusted by the valve opening of the spool to change the discharge capacity. Compressor control valve. Background technique [0002] As a control valve that has a pressure sensing portion that applies a force to a moving member in accordance with the pressure introduced into the pressure sensing portion, and moves the moving member by the force to adjust the valve opening, for example, an air conditioner for a vehicle is known. A control valve used in a variable capacity compressor used for refrigerant compression (refer to Patent Document 1). This control valve uses a bellows assembly in the pressure sensitive part, Figure 5 This is a schematic sectional view of the control valve for such a variable displacement compressor. [0...

AI Technical Summary

Problems solved by technology

[0007] However, the control valve 1 in Patent Document 1 is configured so that the suction pressure Ps acts on the bellows 19 arranged in the pressure sensitive chamber 16 , while the discharge pressure Pd is transmitted from the valve body 5 adjacent to the pressure sensitive chamber 16 . The valve port 11 is introduced, and the connection between the pressure-sensitive chamber 16 and the valve port 11 side is basically cut off by the connecting rod 21, but it is not completely cut off. The refrigerant gas will move from the gap between the connecting rod 21 and the valve body 5, thereby Gas leaks from the discharge pressure Pd side to the suction pressure Ps side, resulting in deterioration of efficiency

In order to avoid this situation, an annular seal can be used on the connecting rod 21 to block the communication between the pressure-sensitive chamber 16 and the valve port 11 side, but when the moving part moves, the annular seal has an effect on the connecting rod 21 that is linked with the moving part. Sliding resistance is imposed by the movement, and the valve opening position of the moving part cannot be obtained accurately, and it is difficult to maintain an appropriate suction pressure corresponding to the solenoid thrust

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