Patent ID: 6135722
Filing Date: 2000-10-24
Classification: F04B

Abstract:
A variable displacement compressor comprising:a housing defining a crankcase, the housing including a cylinder block defining a cylinder bore and a central bore, the cylinder block having a front surface extending from the front end of the central bore to the periphery of the cylinder block, the cylinder bore and the central bore having parallel axes, wherein the central bore has a cylindrical surface and a front end of the central bore opens to the crankcase at a front surface of the cylinder block, and the front surface of the cylinder block is generally planar and perpendicular to the axis of the central bore;a drive shaft supported by the housing, the drive shaft having a front end and a rear end, wherein a mid-portion of the drive shaft is located in the crank case and the rear end of the drive shaft is located in and coaxial to the central bore;a swash plate supported on the drive shaft, the swash plate being pivotally supported to rotate integrally with the drive shaft and to incline with respect to a plane perpendicular to the axis of the drive shaft between a maximum inclination and a minimum inclination, wherein the swash plate moves generally in the axial direction of the drive shaft when the inclination changes;a piston located in the cylinder bore, the piston being connected to the swash plate such that rotation of the swash plate is converted to reciprocal movement of the piston, and the stroke of the piston is determined by the inclination of the swash plate;a fluid passage having an inlet and an outlet, wherein fluid flows from the inlet to the outlet via the cylinder bore; anda hollow, cylindrical shutoff member located in the central bore between the drive shaft and the cylindrical surface for shutting the fluid passage, the shutoff member having an inner surface, wherein the shutoff member moves axially along the central bore when the inclination of the swash plate changes such that, when the inclination of the swash plate increases, the shutoff member follows the swash plate toward the front end of the drive shaft and a front section of the shutoff member loses contact with the cylindrical surface of the central bore, the shutoff member having a radial load bearing area on its inner surface for bearing radial loads applied between the drive shaft and the shutoff member, the front end of the central bore remaining on the front side of a plane perpendicular to the axis of the drive shaft that bisects the load bearing area, regardless of the axial position of the shutoff member.