Piston ring for a piston in a refrigerant compressor

Claim 1

In a refrigerant compressor including a compressor housing having a plurality of cylinders and a crank chamber adjacent said cylinders, a reciprocable piston slidably fitted within each of said cylinders, a driving mechanism coupled to said pistons to move said pistons in a reciprocating motion, a valve plate with valve openings covering one end of said cylinders and a cylinder head covering said valve plate and including a suction chamber and a discharge chamber aligned with said valve openings, the improvement comprising two annular grooves provided toward opposite ends on the outer peripheral surface of each of said pistons and a conical shaped piston ring disposed within each of said annular groove, each said piston ring having an outer diameter larger than the outer diameter of said piston at normal temperatures, each said piston ring having an outer surface facing the wall of the cylinder in which the ring is located and having an inner surface facing toward the center of the piston on which the ring is located, each ring having the outer surface curved convexly in an axial direction and having the inner surface curved concavely in an axial direction, each conical piston ring being curved so that the outer diameter of said curved surface at one end of each of said piston rings is longer than that at the other end to form the base of the conical ring, and wherein one of said piston rings on each piston is disposed on said piston with the base of said conical shaped piston ring facing said valve plate, the thickness of each ring between the inner and outer surfaces being significantly less than half the height of the ring.