Patent ID: 7530797

Claim:
A variable displacement compressor for use with a refrigerant gas, the variable displacement compressor comprising: a cam plate; a crank chamber including a drive shaft and a piston in which the cam plate is arranged in the crank chamber for operably connecting the drive shaft and the piston, wherein the crank chamber is supplied with the refrigerant gas at high pressure from a refrigerant gas discharge region while refrigerant gas bleeds from the crank chamber to a suction chamber through a bleed passage so as to adjust internal pressure of the crank chamber, the cam plate being adjustable to incline at an inclination angle that is in accordance with the internal pressure of the crank chamber in order to change the stroke of the piston; a gas passage formed in the drive shaft, extending in an axial direction of the drive shaft, and connected to the suction chamber; a bearing device and a seal device arranged at a front end portion of the drive shaft; an oil lubrication passage for lubricating the bearing device and the seal device; a first gas inlet passage connecting the gas passage and the crank chamber via the oil lubrication passage; a second gas inlet passage directly connecting the gas passage and the crank chamber; and a sleeve supported on the drive shaft and moved in the axial direction of the drive shaft as the cam plate inclines to change an open amount of the second gas inlet passage, the open amount of the second gas inlet passage being changed by the sleeve to adjust the amount of refrigerant gas drawn into the gas passage through the first gas inlet passage, wherein flow of the refrigerant gas between the gas passage and the crank chamber through the second gas inlet passage is substantially completely disconnected when the cam plate is adjusted to incline at a maximum inclination angle to cause the sleeve to close the second gas inlet passage.