Displacement control valve of clutchless variable displacement inclined plate-type compressor

摘要

A displacement control valve of a clutchless variable displacement inclined plate-type compressor for controlling the discharge displacement of the compressor by opening and closing a communication path between a discharge chamber and a crank chamber. The displacement control valve has a valve hole (106) formed in the communication path and always communicating with the discharge chamber, an inside control valve (100) for opening and closing the valve hole (106) by a valve body (112) operated in response to expansion and contraction of a pressure sensing member (109) for sensing a suction pressure, and an operation switching device (120) connected to the inside control valve for switching the inside control valve between an operating condition where the valve body opens and closes the valve hole in response to the expansion and contraction of the pressure sensing member and a non-operating condition where the valve body opens the valve hole independently of the expansion and contraction of the pressure sensing member. In this displacement control valve, because a discharge pressure Pd acts on both the valve body (112) and a pressure sensing rod (110), the force of the discharge pressure Pd for urging the valve body (112) in a valve opening direction is (Sr−Sv)Pd. The displacement control valve can be made smaller than conventional displacement control valves because (Sr−Sv) is very small.