Variable displacement compressor

Claim 1

In a variable displacement compressor comprising a rotary shaft journaled by a stationary part, a cylinder block arranged in a fixed relationship with said rotary shaft and formed with a plurality of through holes, pistons respectively received in said through holes and defining therein working fluid chambers, and piston means including a wobble plate arranged in opposition to said cylinder block and rotatably holding one end of said pistons, the compressor being constructed such that, when the cylinder block is rotated together with said rotary shaft, a fluid is sucked from a low pressure chamber into said working fluid chambers and is discharged therefrom into a high pressure chamber, the improvement comprising: said wobble plate is supported on said rotary shaft for wobbling movement, said piston drive means further includes a pair of drive pins each having one end portion secured to said cylinder block and extending in parallel with said rotary shaft and the other end portions slidably engaging with said wobble plate through spherical bearings, a swash plate having an inclination surface making a sliding contact with a back surface of said wobble plate and supported by a swivel plate support member through a hinge mechanism at one part thereof for an inclination movement in an axial direction of said rotary shaft, said swash plate support member includes an annular spacer having one surface fixed to an inner surface of a casing and an opposite surface constituting an inclination surface, and operation means operably connected to said swash plate to move the latter for varying an inclination angle of said wobble plate, said operation means includes a piston mechanism adapted to be driven by a fluid pressure, said piston mechanism being embedded in said swash plate support member and engaging with said swash plate, said piston mechanism having a working chamber communicating with said high pressure chamber and including a piston means operated in accordance with a difference in pressure between said low pressure chamber and said high pressure chamber, and a spring for constantly biasing said piston means to closely contact said swash plate, and wherein said piston means has a smaller diameter end portion of spherical configuration which engages with a recess formed in said swash plate.