Patent ID: 6164925
Filing Date: 2000-12-26
Classification: F04B,F25B

Abstract:
A control valve for controlling displacement of a variable displacement compressor, wherein the compressor includes a suction pressure zone, the pressure of which is a suction pressure, a discharge pressure zone, a control chamber, the pressure of which is a control pressure, and a pressurizing passage through which refrigerant is sent to the control chamber from the discharge pressure zone, wherein the control valve adjusts the amount of refrigerant sent to the control chamber from the discharge pressure zone to control the compressor displacement such that the control pressure is raised and the compressor displacement is decreased when the amount of refrigerant sent to the control chamber from the discharge pressure zone increases, and the control pressure is lowered and the compressor displacement is increased when the amount of refrigerant sent to the control chamber from the discharge pressure zone decreases, wherein the control valve comprises:a valve body for adjusting the opened area of the pressurizing passage;an electric drive means for urging the valve body in a first direction with a force corresponding to the value of the current fed to the electric drive means;a first pressure chamber to which the control pressure of the control chamber is communicated;a second pressure chamber to which the suction pressure of the suction pressure zone is communicated; anda pressure sensing element partitioning the first pressure chamber and the second pressure chamber from each other, wherein the difference between the pressure of the first pressure chamber and the pressure of the second pressure chamber produces a force that causes the pressure sensing element to urge the valve body in a second direction, which is opposite to the first direction, wherein a target value of the pressure difference between the first and second pressure chambers is determined by the urging force of the electric drive means, the pressure sensing element moves the valve body to decrease the opened area of the pressurizing passage and return the pressure difference to the target value when the suction pressure communicated to the second pressure chamber increases, and the pressure sensing element moves the valve body to increase the opened area of the pressurizing passage and return the pressure difference to the target value when the suction pressure communicated to the second pressure chamber decreases.