Patent ID: 7857601

Claim:
A variable displacement compressor having a discharge chamber, a suction chamber and a crank chamber, said compressor comprising: an electromagnetic displacement control valve disposed at a position in a discharge pressure supply passageway capable of communicating with said crank chamber from said discharge chamber; and a fixed orifice disposed at a position in a pressure relief passageway communicating with said suction chamber from said crank chamber; said electromagnetic displacement control valve having a valve body configured to open and close said discharge pressure supply passageway in response to an electromagnetic force from said electromagnetic displacement control valve to adjust a pressure in said crank chamber to control a piston stroke; wherein a part of said discharge pressure supply passageway and a part of said pressure relief passageway are formed as a common passageway communicating with an end of said crank chamber; and wherein a part of said common passageway is formed as a passageway through a bearing for a compressor main shaft; and wherein said common passageway is configured such that, during displacement control, as said valve body is moved from a closed position to an open position, a gas flow occurs from said discharge chamber to said crank chamber through said common passageway, and when said valve body is in the closed position or the open position, a gas flow occurs from said crank chamber to said suction chamber through said common passageway.