Hermetic refrigerant compressor and refrigerator-freezer using the same

Abstract

A hermetic refrigerant compressor (100) includes a sealed container (101) in which lubricating oil (103) having a kinematic viscosity in a range of 1 to 9 mm2/S at 40° C. is stored, the lubricating oil (103) containing a sliding modifier that is either sulfur or a sulfur-containing compound. A compression element (107) includes a shaft part that is a crank shaft (108). In a case where a sliding surface of a main shaft (109) is a single sliding surface, a length of the single sliding surface in an axial direction is a single sliding length L, whereas in a case where the sliding surface is divided into a plurality of sliding surfaces, a length of one of the sliding surfaces in the axial direction, the one sliding surface having the least length in the axial direction among the plurality of sliding surfaces, is the single sliding length L, and a ratio L/D of the single sliding length L to an external diameter D of the main shaft (109) is less than or equal to 0.51.

1 . A hermetic refrigerant compressor comprising a sealed container in which lubricating oil having a kinematic viscosity in a range of 1 mm 2 /S to 9 mm 2 /S at 40° C. is stored, the sealed container accommodating an electric element and a compression element, the compression element being driven by the electric element and configured to compress a refrigerant, wherein
 the compression element includes:
 a shaft part that is a crank shaft including a main shaft and an eccentric shaft; and 
 a bearing part that pivotally supports the shaft part, the bearing part including a main bearing and an eccentric bearing, the main bearing pivotally supporting the main shaft, the eccentric bearing pivotally supporting the eccentric shaft, 
 
 the main shaft includes a sliding surface that slides on the main bearing, the sliding surface being either a single sliding surface or divided into a plurality of sliding surfaces, 
 in a case where the sliding surface is the single sliding surface, a length of the single sliding surface in an axial direction is a single sliding length L, whereas in a case where the sliding surface is divided into the plurality of sliding surfaces, a length of one of the sliding surfaces in the axial direction, the one sliding surface having the least length in the axial direction among the plurality of sliding surfaces, is the single sliding length L, and a ratio L/D of the single sliding length L to an external diameter D of the main shaft is less than or equal to 0.51, and 
 the lubricating oil contains a sliding modifier that is either sulfur or a sulfur-containing compound. 
 
     
     
         2 . The hermetic refrigerant compressor according to  claim 1 , wherein
 in the case where the sliding surface is divided into the plurality of sliding surfaces, when a total of the lengths of the plurality of sliding surfaces in the axial direction is a total sliding length Lt, a ratio Lt/D of the total sliding length Lt to the external diameter D is less than or equal to 1.26.   
     
     
         3 . The hermetic refrigerant compressor according to  claim 1 , wherein
 the ratio L/D is greater than or equal to 0.15.   
     
     
         4 . The hermetic refrigerant compressor according to  claim 2 , wherein
 the ratio Lt/D is greater than or equal to 0.3.   
     
     
         5 . The hermetic refrigerant compressor according to  claim 1 , wherein
 a content of the sliding modifier in the lubricating oil in terms of an atomic weight of sulfur is greater than or equal to 100 ppm.   
     
     
         6 . The hermetic refrigerant compressor according to  claim 1 , wherein
 the lubricating oil further contains a phosphorus-based extreme-pressure additive.   
     
     
         7 . The hermetic refrigerant compressor according to  claim 1 , wherein
 the electric element is inverter-driven at a plurality of operating frequencies.   
     
     
         8 . A refrigerator-freezer comprising a refrigerant circuit including:
 the hermetic refrigerant compressor according to  claim 1 ;   a radiator;   a decompressor; and   a heat absorber, wherein   in the refrigerant circuit, the hermetic refrigerant compressor, the radiator, the decompressor, and the heat absorber are connected by piping in an annular manner.