Patent ID: 8172552
Filing Date: 2012-05-08
Classification: F04B

Abstract:
1. A variable displacement compressor, wherein the compressor draws a gaseous refrigerant from a suction pressure zone and discharges the gaseous refrigerant to a discharge pressure zone, and controls a displacement of the compressor according to a pressure in a control pressure chamber, the compressor comprising: a cam body provided in the control pressure chamber, wherein an inclination angle of the cam body is changeable based on the pressure in the control pressure chamber; a piston that reciprocates in a cylinder bore as the cam body rotates; a supply passage for supplying the gaseous refrigerant in the discharge pressure zone to the control pressure chamber, wherein a flow passage area of the supply passage is controlled by an electromagnetic displacement control valve; a release passage for discharging the gaseous refrigerant in the control pressure chamber to the suction pressure zone, the release passage operating to control the pressure in the control pressure chamber and the displacement; an on-off valve that responds to changes in a temperature of the on-off valve to selectively open and close the release passage, wherein, when the temperature of the on-off valve is lower than a predetermined temperature, the on-off valve opens the release passage to allow the gaseous refrigerant to flow out to the suction pressure zone from the control pressure chamber through the release passage so that the pressure in the control pressure chamber is adjustable, and wherein, when the temperature of the on-off valve is equal to or higher than the predetermined temperature, the on-off valve shuts off the release passage to prevent the gaseous refrigerant from flowing out to the suction pressure zone from the control pressure chamber through the release passage so that the pressure in the control pressure chamber is increased to reduce the displacement, and wherein the predetermined temperature is greater than a vaporization temperature of the refrigerant, and, wherein the on-off valve is located in the control pressure chamber.