Variable capacity compressor

Abstract

For a refrigerant compressor having two capacities, a camming structure operable in different manners depending on direction of crankshaft rotation, to achieve each capacity while providing top dead center piston operation thru the use of a circular cam bushing which is eccentrically, rotatably mounted on the crankshaft eccentric and within the connecting rod bearing wherein the combined eccentricities of the bushing and the eccentric equal the primary stroke of the piston. A first stop mechanism is provided for stabilizing the bushing on the eccentric upon rotation of the crankshaft in one direction whereby the eccentricities of the eccentric and bushing become aligned and remain so during synchronous rotational orbiting motion of the eccentric and bushing during rotation of the crankshaft for producing full stroke and full capacity. A second stop mechanism is provided for stabilizing the bushing within the bearing upon opposite rotation of the crankshaft whereby the bushing eccentricity becomes and remains substantially aligned with the connecting rod stroke axis while the eccentric moves alone thru its rotational orbit for producing reduced stroke and reduced capacity. A unique electrical control system is also provided for a reversible electric induction motor for selectively and efficiently driving the compressor crankshaft in either direction for providing the different capacities.