Compressor and refrigerating cycle apparatus using the same

Abstract

In a compressor, a single refrigerant of hydrofluoroolefin having a double bond of carbon or a mixed refrigerant containing hydrofluoroolefin and hydrofluorocarbon having no double bond of carbon is used, and moreover a refrigerating machine oil containing an additive for suppressing deterioration of the refrigerating machine oil and an antiwear agent is used, the compressor including a sliding portion which is exposed to the mixed refrigerant and the refrigerating machine oil and which has a hardness of 47-55 HRC. Thus, decomposition and polymerization of the refrigerant and the refrigerating machine oil can be inhibited (i.e., occurrence of sludge can be inhibited), and antiwear property of sliding portions, e.g. vane and piston, of the compressor can be maintained. As a result, reliability of the compressor and the refrigerating cycle apparatus using the compressor can be ensured.

1 . A compressor for use in a refrigerating cycle apparatus, wherein
 a single refrigerant of hydrofluoroolefin having a double bond of carbon or a mixed refrigerant containing the hydrofluoroolefin and hydrofluorocarbon having no double bond of carbon is used, and   a refrigerating machine oil containing an additive for suppressing deterioration of the refrigerating machine oil and an antiwear agent is used, the compressor including   a sliding portion which is exposed to the mixed refrigerant and the refrigerating machine oil and which has a hardness of 47-55 HRC.   
     
     
         2 . The compressor according to  claim 1 , including, as the sliding portions, a piston and a vane which are put into sliding contact with each other. 
     
     
         3 . The compressor according to  claim 2 , wherein the vane is made from an iron-related material and subjected to nitriding treatment or made from a sintered alloy steel and subjected to sintering treatment and quenching treatment. 
     
     
         4 . The compressor according to  claim 3 , wherein the iron-related material or the sintered alloy steel is a high-speed tool steel. 
     
     
         5 . The compressor according to  claim 3 , wherein ceramic coating is applied to the vane. 
     
     
         6 . The compressor according to  claim 5 , wherein by the ceramic coating, a surface of the vane is coated with a nitride or carbide of Ti (titanium), V (vanadium), Ta (tantalum), W (tungsten) or Nb (niobium). 
     
     
         7 . The compressor according to  claim 5 , wherein the ceramic coating of a tip end portion of the vane to be put into contact with the piston has a thickness of 5-15 μm. 
     
     
         8 . The compressor according to  claim 5 , wherein the ceramic coating is applied to only the tip end portion of the vane. 
     
     
         9 . The compressor according to  claim 2 , wherein the vane is made from a ceramic material. 
     
     
         10 . The compressor according to  claim 2 , wherein the piston is made from cast iron. 
     
     
         11 . The compressor according to  claim 10 , wherein the cast iron contains 0.4-1.2 wt % of chromium and 0.15-0.7 wt % of molybdenum. 
     
     
         12 . The compressor according to  claim 11 , wherein the cast iron contains 0.15-0.4 wt % of nickel. 
     
     
         13 . The compressor according to  claim 2 , wherein a surface of the vane and a surface of the piston have surface roughnesses of 0.4 μm Ra or less. 
     
     
         14 . The compressor according to  claim 1 , wherein the refrigerant contains at least one of tetrafluoropropene or trifluoropropene, which is a kind of hydrofluoroolefin, and has a global warming potential within a range of 5 to 750, desirably 5 to 350. 
     
     
         15 . The compressor according to  claim 1 , wherein
 the refrigerant contains, as a principal ingredient, tetrafluoropropene or trifluoropropene, which is a kind of hydrofluoroolefin, and   difluoromethane and pentafluoroethane are mixed in the refrigerant so that its global warming potential falls within a range of 5 to 750, desirably 5 to 350.   
     
     
         16 . The compressor according to  claim 1 , wherein the refrigerating machine oil includes (1) polyoxyalkylene glycols, (2) polyvinyl ethers, (3) poly(oxy)alkylene glycol or copolymers of its monoether and polyvinyl ether, (4) oxygenated compounds of polyol esters and polycarbonates, (5) a synthetic oil having a principal ingredient of alkylbenzenes or (6) a synthetic oil having a principal ingredient of α-olefins. 
     
     
         17 . A refrigerating cycle apparatus comprising:
 the compressor according to  claim 1 ;   a condenser;   an expansion mechanism; and   an evaporator, whereby   a refrigerating cycle for compressing, condensing, expanding and evaporating the refrigerant is constituted.