Patent ID: 6428286
Filing Date: 2002-08-06
Classification: F04C

Abstract:
In a capacity-controlled scroll compressor comprising; a compressor housing; a fixed scroll having a fixed end plate and a spiral wrap extending from said fixed end plate; an orbiting scroll having an orbiting end plate and a spiral wrap extending from said orbiting end plate and disposed in engagement with said fixed scroll with respective wraps facing each other; said wraps of said fixed scroll and said orbiting scroll intermeshed to define a plurality of fluid compression pockets and positioned to receive fluid to be compressed from a suction chamber in said housing, said fixed scroll and said orbiting scroll being disposed inside of said compressor housing; an orbiting mechanism formed on the rear side of said orbiting end plate opposite the spiral wrap of said orbiting scroll; a drive shaft rotatably supported in said compressor housing with the main shaft portion thereof projecting to outside of said compressor housing passing through a shaft sealing device and a subsidiary bearing through a main bearing; a drive transmission mechanism for transmitting the driving force from said drive shaft to said orbiting mechanism; a rotation restraining component for restraining rotation of said orbiting scroll as to make it orbit; a revolution restraining component adjacent to said rotation restraining component for restraining the direction of motion of said rotation restraining component to the direction at right angles to said drive shaft; a discharge port formed in said fixed end plate communicating with the fluid compression pocket near the end of its formation; and a discharge valve at the end of said discharge port;an improved capacity control mechanism comprising: at least a pair of bypass holes in said fixed end plate communicating with a pair of fluid compression pockets formed in between both wraps at positions substantially symmetrical with respect to said fixed end plate; a cylinder formed inside said fixed end plate in a manner communicating with said pairs of fluid pockets through said bypass holes; a shuttle valve inside said cylinder mounted for reciprocal motion therein to vary the opening of said bypass holes to change the capacity of said compressor; a spring in said cylinder opposing reciprocation of said shuttle valve; a fixed end plate further including a control-pressure chamber housing a pressure control valve for generating a control pressure for causing the reciprocation of said shuttle valve against said spring responsive to said control pressure; and a high pressure passage in said fixed end plate between said control-pressure chamber and said discharge port of said fixed end plate located before said discharge valve for introducing said compressed fluid at relatively high pressure to said pressure control valve wherein said pressure control valve generates a control pressure from said relatively high pressure fluid responsive to pressure in said compressor housing.