Radial Bearing Arrangement in a Refrigeration Compressor

Abstract

The compressor includes a bearing hub, defining a radial bearing having a first and a second end portion and supporting a crankshaft having an eccentric end portion supporting the larger eye of a connecting rod coupled to the piston, for example, by a smaller eye mounted around a piston pin. The second end portion and, optionally, the first end portion of the bearing hub and the larger and smaller eyes of the connecting rod are internally provided with bushings. End portions of the bearing hub and of the larger and smaller eyes may have their structure resistant to the pressing of a confronting compressor component supported on said end portions, or further present a terminal portion elastically deformable together with a confronting terminal portion of the associated bushing.

1 . A radial bearing arrangement in a refrigeration compressor of the type which comprises: a crankcase carrying a cylinder and a bearing hub defining a radial bearing; a crankshaft mounted in the radial bearing and having an eccentric end portion and a free end portion which project outwardly from the first and from the second end portion, respectively, of the bearing hub; a piston lodged in the cylinder; a connecting rod coupling the eccentric end portion of the crankshaft to the piston, said arrangement being characterized in that at least the second end portion, among the first and the second end portions of the bearing hub, is defined by a respective bushing, made of a material with low friction coefficient, which is totally affixed in the interior of the bearing hub. 
     
     
         2 . The arrangement, according to  claim 1 , characterized in that the bushing is radially and externally seated against the second end portion, of the bearing hub which presents a structure resistant to the pressing of a confronting region of the crankshaft presenting a coaxiality deviation of its axis in relation to the axis of the radial bearing. 
     
     
         3 . The arrangement, according to  claim 2 , characterized in that the bushing is radially and externally seated against the first end portion, of the bearing hub, which presents a structure resistant to the pressing of a confronting region of the crankshaft presenting a coaxiality deviation of its axis in relation to the axis of the radial bearing. 
     
     
         4 . The arrangement, according to  claim 1 , characterized in that the second end portion of the bearing hub presents a terminal portion against which is radially and externally seated an end portion of the bushing, said terminal portion presenting a reduced radial thickness so as to be elastically and radially deformed, outwardly, jointly with the end portion of the bushing, when the latter is pressed by a confronting region of the crankshaft presenting a coaxiality deviation of its axis in relation to the axis of the radial bearing. 
     
     
         5 . The arrangement, according to  claim 4 , characterized in that the first end portion of the bearing hub incorporates a terminal portion which projects axially outwardly from the crankcase and against which is radially and externally seated an end portion of the bushing, said terminal portion presenting a reduced radial thickness to be elastically and radially deformed, outwardly, jointly with the end portion of the bushing, when the latter is pressed by a confronting region of the crankshaft presenting a coaxiality deviation of the axis thereof in relation to the axis of the radial bearing. 
     
     
         6 . The arrangement, according to  claim 4 , characterized in that the end portion of the bushing defines, together with a confronting part of the crankshaft and in the elastically deformed condition, a region of confronting surfaces having dimensions in the axial and circumferential directions capable of maintaining, in said region, an oil film that separates, at least partially, the surfaces which form said region of confronting surfaces. 
     
     
         7 . The arrangement, according to  claim 1 , in which the connecting rod presents a larger eye mounted around the eccentric end portion of the crankshaft, the arrangement being characterized in that the larger eye of the connecting rod affixes, totally contained therein, a bushing having low friction coefficient, defining the bearing surface of the larger eye in relation to the eccentric end portion of the crankshaft. 
     
     
         8 . The arrangement, according to  claim 7 , characterized in that the larger eye of the connecting rod presents an end portion facing the bearing hub and against which is radially and externally seated an end portion of the bushing, said end portion of the larger eye presenting a structure resistant to the pressing of the end portion of the bushing by a confronting region of the eccentric end portion of the crankshaft presenting a coaxiality deviation of the axis thereof in relation to the axis of the larger eye. 
     
     
         9 . The arrangement, according to  claim 7 , characterized in that the larger eye of the connecting rod presents an end portion facing the bearing hub and incorporating a terminal portion against which is radially and externally seated an end portion of the bushing, said terminal portion presenting a reduced radial thickness to be elastically and radially deformed, outwardly, jointly with the end portion of the bushing, when the latter is pressed by a confronting region of the eccentric end portion of the crankshaft presenting a coaxiality deviation of the axis thereof in relation to the axis of the larger eye. 
     
     
         10 . The arrangement, according to  claim 1 , in which the connecting rod presents a smaller eye mounted around a piston pin, the arrangement being characterized in that the smaller eye of the connecting rod affixes, totally contained therein, a bushing having low friction coefficient, defining the bearing surface of the smaller eye in relation to the piston pin. 
     
     
         11 . The arrangement, according to  claim 10 , characterized in that the smaller eye of the connecting rod presents an end portion facing the bearing hub and against which is radially and externally seated an end portion of the bushing, said end portion of the smaller eye presenting a structure resistant to the pressing of the end portion of the bushing, when the latter is pressed by a confronting region of the piston pin, presenting a coaxiality deviation of its axis in relation to the axis of the smaller eye. 
     
     
         12 . The arrangement, according to  claim 10 , characterized in that the smaller eye of the connecting rod presents an end portion facing the bearing hub and incorporating a terminal portion against which is radially and externally seated an end portion of the bushing, said terminal portion presenting a reduced radial thickness so as to be elastically and radially deformed, outwardly, jointly with the end portion of the bushing, when the latter is pressed by a confronting region of the piston pin presenting a coaxiality deviation of its axis in relation to the axis of the smaller eye. 
     
     
         13 . The arrangement, according to  claim 9 , characterized in that the end portion of the bushing defines, together with a confronting part of one of the parts defined by the eccentric portion of the crankshaft and by the piston pin and in the elastically deformed condition, a region of confronting surfaces, having dimensions, in the axial and circumferential directions which are capable of maintaining, in said region, an oil film which, at least partially, separates the surfaces that form said region of confronting surfaces. 
     
     
         14 . The arrangement, according to  claim 6 , characterized in that the region of confronting surfaces takes an approximately semi-elliptical form, with the end edge thereof matching the marginal edge of the adjacent end portions of each bushing. 
     
     
         15 . The arrangement, according to  claim 1 , characterized in that the bushing is formed by a combination of layers of metal and polymer, in which the latter is the innermost. 
     
     
         16 . The arrangement, according to  claim 1 , characterized in that the bushing is formed by an antifriction tubular portion obtained in polymeric material and incorporated and retained inside an external metallic tubular substrate. 
     
     
         17 . The arrangement, according to  claim 16 , characterized in that the metallic tubular substrate is defined by a steel strip with an inner face incorporating a sintered bronze layer, the antifriction tubular portion of polymeric material being affixed over the sintered bronze layer of the metallic tubular substrate.