Variable displacement compressor

Abstract

A vehicular air conditioning refrigerant compressor is disclosed. The variable displacement compressor includes a suction chamber, a discharge chamber, a crank chamber, a drive shaft having rotated by a vehicle engine, a swash plate rotatable with the drive shaft and located within the crank chamber. The swash plate and the drive shaft have a tilt angle between them. The tilt angle is controlled by a control valve mechanism which regulates the introduction of a gas from the discharge chamber to the crank chamber. The compressor further includes a center sleeve slidably mounted on the drive shaft. The position of the center sleeve is responsive to the tilt angle. The compressor also includes a relief passage for relieving gas from the crank chamber to the suction chamber, and includes an axial hole in the drive shaft having an opening at one end of the drive shaft and an end within the drive shaft, a vertical hole in the drive shaft having two openings on the surface of the drive shaft and perpendicular to said axial hole. The vertical hole intersects the axial hole near the end of the axial hole. The relief passage further includes a passage in fluid connection with the suction chamber and the opening of the axial hole. The aperture of the two openings is regulated by the position of the center sleeve.