Control system for variable displacement compressor

Claim 1

A variable displacement compressor comprising a plurality of cylinders and pistons cooperating to provide gas working spaces, each said cylinder having a suction and discharge port cooperating therewith; a wobble plate connected to said pistons and imparting the reciprocating force to actuate said pistons; a drive shaft; a cam mechanism driven by said drive shaft and cooperating with said wobble plate, said wobble plate and cam mechanism being pivoted at a point spaced from the drive shaft axis and movable from a position wherein said wobble plate is positioned along a plane substantially normal to said drive shaft axis to a position angularly displaced from said normal plane; a mounting element supporting said cam mechanism, and mounting element having an outer spherical surface engaging said cam mechanism and a central bore through which said drive shaft extends, said mounting element being slidable to and fro on said drive shaft as the wobble plate angle is changed; and a fluid actuator comprising a piston and cylinder arrangement in which increased pressure in said actuator cylinder causes the actuator piston to move said wobble plate in a direction toward said normal plane, reducing the stroke length of said pistons; and means for supplying high pressure gas from said gas working spaces to said actuator cylinder, said last-named means including a control valve responsive to a variable indicative of capacity requirements.