| 摘要 |
In a control valve for a variable displacement compressor, for controlling the discharge flow rate of refrigerant to be constant, to dispense with a check valve in a refrigerant outlet port of the compressor. The control valve includes a first control valve that controls the passage cross-sectional area of a refrigerant passage through which refrigerant passes from a discharge chamber of the compressor to a refrigerant outlet port thereof, and a second control valve that controls the flow rate of refrigerant allowed to flow from the discharge chamber to a crankcase such that a differential pressure (Pdh-Pdl) across the first control valve generated by the refrigerant passing therethrough becomes constant. The control valve is configured such that when a solenoid section is not energized, a first valve element is engaged with a piston to forcibly fully open the second control valve. The piston has an outer diameter equal to the inner diameter of a second valve seat, so that the discharge pressure Pdl on a refrigerant outlet port side is inhibited from adversely affecting the fully-opening operation of the second control valve, to thereby maintain the fully-closed state of the first control valve. This makes it possible to dispense with a check valve conventionally provided in the refrigerant outlet port.
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