CONTROL DEVICE AND PRESSURE CONTROL VALVE FOR VARIABLE DISPLACEMENT COMPRESSOR

摘要

A control device for a variable displacement compressor, which, at the minimum discharge capacity, secures a sufficient refrigerant circulation route inside a compressor, and at an intermediate discharge capacity, reduces the amount of controlling gas to increase compressor efficiency, thereby saving power. In the control device, the area of a path communicating a control pressure chamber and a suction pressure region and the area of a path communicating a discharge pressure region and the control pressure chamber are varied to control the pressure in the control pressure chamber. As the pressure difference between the discharge pressure region and the regions other than that becomes smaller, the area of the path communicating the control pressure chamber and the suction pressure region is gradually reduced to a first predetermined value of the difference, and gradually increased when the difference is equal to or less than the first predetermined value. Further, as the pressure difference between the discharge pressure region and the regions other than that becomes smaller, the area of the path communicating the discharge pressure region and the control pressure chamber is increased up to a second predetermined value of the difference, and when the difference is at the second predetermined value or less, the area is gradually increased at a variation rate higher than that used up to the second predetermined value.