Rotary compressor

Abstract

The eccentric on the crankshaft of a rotary compressor, as well as the roller that surrounds the crankshaft, is replaced by an elliptical cam that acts as a double eccentric. In this manner, the elliptical cam provides for proper balancing of the crankshaft and other components of the compressor, while eliminating the need to use counterweights. Specifically, the elliptical cam is symmetrical, resulting in equal forces acting on opposing sides of the elliptical cam. This allows the elliptical cam to maintain its balance throughout its rotation, even when operating at a high rate of revolution.

1 . A rotary compressor, comprising:
 an outer hermetic housing;   a motor having a stator and a rotor;   a cylinder having an inner cylindrical surface including a plurality of slots formed therein, said inner cylindrical surface defining a substantially cylindrical bore;   a crankshaft having an elongate cam, said elongate cam having an outer surface, said elongate cam of said crankshaft being rotatably disposed within said cylinder block, wherein the outer surface of the cam contacts the inner cylindrical surface of the cylinder block at two circumferentially spaced positions to form a pair of working pockets;   a first vane positioned at least partially within one of said plurality of slots of said cylinder, said first vane biased inwardly to contact the outer surface of said elongate cam;   a second vane positioned at least partially within another of said plurality of slots of said cylinder, said second vane biased inwardly to contact the outer surface of said elongate cam;   an outboard bearing positioned adjacent said cylinder block;   a suction pressure inlet in fluid communication with said working pockets to supply suction pressure working fluid to said working pockets; and   a main bearing at least partially defining a discharge port in fluid communication with said working pockets at certain rotation angles of said elongate cam.   
     
     
         2 . The compressor of  claim 1 , wherein:
 said main bearing is disposed between said motor and a first axially end of said cylinder, said crankshaft extending through said main bearing and being rotatably supported therein; and   said outboard bearing is an outboard thrust bearing disposed adjacent a second axial end of said cylinder block to support said elongate cam substantially only against axial movement of said cam.   
     
     
         3 . The compressor of  claim 2 , wherein said outboard bearing includes a suction passage therein in fluid communication with said suction inlet and extending across said outboard bearing to a position that is on an opposite side of said elongate cam from said suction inlet, said suction passage being in fluid communication with said working pockets. 
     
     
         4 . The compressor of  claim 3 , wherein said suction passage is formed as a slot in a thrust surface of said outboard thrust bearing facing said cylinder bore. 
     
     
         5 . The compressor of  claim 4 , wherein said suction inlet is on the cylindrical wall of said cylinder bore. 
     
     
         6 . The compressor of  claim 3 , wherein said suction inlet is on the cylindrical wall of said cylinder bore. 
     
     
         7 . The compressor of  claim 4 , wherein said outboard thrust bearing includes an oil passage in communication with an oil sump in said outer housing and a boss surrounding said oil passage, said boss having a side wall including tapered portions aligned with a longitudinal axis of said slot to smooth the flow of suction fluid around said boss. 
     
     
         8 . The compressor of  claim 3 , and including a further suction passage in said main bearing in fluid communication with said working pockets. 
     
     
         9 . The compressor of  claim 2 , and including a suction passage in said main bearing in fluid communication with said working pockets. 
     
     
         10 . The compressor of  claim 1 , wherein said crankshaft is devoid of a counterweight. 
     
     
         11 . The compressor of  claim 1 , including at least one suction fluid cross passage extending through said elongate cam to convey suction pressure fluid between said working pockets. 
     
     
         12 . The compressor of  claim 11 , wherein said elongate cam is elliptical and said cam suction fluid passage is disposed at an angle to a major chord of said elliptical cam. 
     
     
         13 . The compressor of  claim 1 , wherein said elongate cam is elliptical. 
     
     
         14 . The compressor of  claim 10 , wherein said elongate cam is elliptical. 
     
     
         15 . A rotary compressor, comprising:
 an outer hermetic housing;   a motor having a stator and a rotor;   a cylinder having an inner cylindrical surface including a plurality of slots formed therein, said inner cylindrical surface defining a substantially cylindrical bore;   a crankshaft having an elongate cam, said elongate cam having an outer surface and being rotatably disposed within said cylinder block, the outer surface of said elongate cam contacting the inner cylindrical surface of the cylinder bore at two circumferentially spaced positions to form a pair of working pockets;   first and second vanes positioned at least partially within respective ones of said cylinder slots, said vanes biased inwardly to contact the outer surface of said elongate cam;   an outboard thrust bearing positioned adjacent said cylinder block and defining a suction pressure passage therein, said suction pressure passage in simultaneous fluid communication with each of said working pockets to draw suction pressure working fluid from a suction pressure inlet to both of said working pockets; and   a main bearing at least partially defining a discharge port in fluid communication with said working pockets.   
     
     
         16 . The compressor of  claim 15 , wherein:
 said main bearing is disposed between said motor and a first axially end of said cylinder, said crankshaft extending through said main bearing and being rotatably supported therein; and   said outboard thrust bearing is disposed adjacent a second axial end of said cylinder block to support said elongate cam substantially only against axial movement of said cam.   
     
     
         17 . The compressor of  claim 16 , wherein said suction passage is formed as a slot in a thrust surface of said outboard bearing facing said cylinder bore. 
     
     
         18 . The compressor of  claim 17 , wherein said outboard thrust bearing includes an oil passage in communication with an oil sump in said outer housing and a boss surrounding said oil passage, said boss having a side wall including tapered portions aligned with a longitudinal axis of said slot to smooth the flow of suction fluid around said boss. 
     
     
         19 . The compressor of  claim 15 , and including a further suction passage in said main bearing in fluid communication with said working pockets. 
     
     
         20 . The compressor of  claim 15 , wherein said crankshaft is devoid of a counterweight. 
     
     
         21 . The compressor of  claim 15 , wherein said cam is elliptical. 
     
     
         22 . The compressor of  claim 21 , wherein said crankshaft is devoid of a counterweight.