A valve includes a valve housing provided with an inlet port and an outlet port; a valve body configured to be driven by a drive source; a spring that urges the valve body in a direction opposite a direction of driving by the drive source. A valve seat is formed at an edge of a through-flow passage. The valve body and the valve seat forms a poppet valve that controls a flow rate in accordance with a movement of the valve body. A flow passage on a downstream side of the poppet valve is provided with a reduction region where a flow passage cross-sectional area tends to decrease toward a downstream side.

A variable displacement swash plate type compressor includes a displacement control valve. The displacement control valve includes a drive force transmitting member, a valve member having a first valve body, a pressure sensing mechanism, which adjusts the valve opening degree of the first valve body, a communication passage, which connects a back pressure chamber and an accommodating chamber to each other, and a second valve body, which selectively opens and closes the communication passage. The first valve body opens when current supply to an electromagnetic solenoid is stopped and the pressure in a suction pressure zone is less than a threshold value. The second valve body closes when current is supplied to the electromagnetic solenoid and opens when the current supply to the electromagnetic solenoid is stopped and the pressure in the suction pressure zone is greater than or equal to the threshold value.

A control valve according to one embodiment includes a shaft that transmits the solenoidal force to a valve element. A solenoid includes a bottomed sleeve into which the pressure of refrigerant is introduced, a core secured coaxially to the sleeve, a plunger, contained in the sleeve on its bottom side, which is displaceable integrally with the shaft in a direction of axis line, a first spring that applies the biasing force in a valve opening direction to the shaft, a second spring that applies the biasing force in a valve closing direction to the plunger, and a shaft support member, which is press-fitted such that the shaft support member is secured to an inner wall of the sleeve near its bottom portion. The second spring is set between the shaft support member and the plunger.

A control valve according to one embodiment includes a shaft that transmits the solenoidal force to a valve element. The control valve, in one example, ensures high pressure resistance at a mounting part where a control valve is mounted in a variable displacement compressor. A solenoid includes a bottomed sleeve into which the pressure of refrigerant is introduced, a core secured coaxially to the sleeve, a plunger, contained in the sleeve on its bottom side, which is displaceable integrally with the shaft in a direction of axis line, a first spring that applies the biasing force in a valve opening direction to the shaft, a second spring that applies the biasing force in a valve closing direction to the plunger, and a shaft support member, which is press-fitted such that the shaft support member is secured to an inner wall of the sleeve near its bottom portion. The second spring is set between the shaft support member and the plunger.