Rolling bearing, rolling bearing for fuel cell, compressor for fuel cell system and fuel cell system

Abstract

The rolling bearing of the invention to be incorporated in the compressor for fuel cell system comprises a fluorine-based grease containing a fluororesin and a fluorine-based oil, a urea grease containing a urea compound and a synthetic oil or a lithium complex grease containing a lithium complex and a synthetic oil encapsulated therein. In this arrangement, the grease deterioration of the rolling bearing incorporated in the compressor for force-feeding various fluids between machines can be prevented, making it possible to provide a fuel cell system which can maintain stable operation over an extended period of time.

1 . A rolling bearing having a fluorine-based grease containing a fluororesin and a fluorine-based oil, a urea grease containing a urea compound and a synthetic oil or a lithium complex grease containing a lithium complex and a synthetic oil encapsulated therein.  
     
     
         2 - 14 . (canceled)  
     
     
         15 . The rolling bearing as defined in  claim 1 , wherein the urea grease comprises an alkyl-substituted diphenyl sulfide incorporated therein as a base oil of the urea grease in an amount of not smaller than 30% by weight based on the total amount of the base oil and comprises a urea compound incorporated therein as a thickening agent.  
     
     
         16 . The rolling bearing as defined in  claim 15 , wherein the percent oil separation of the urea grease is not greater than 1.0% by weight.  
     
     
         17 - 20 . (canceled)  
     
     
         21 . The rolling bearing as defined in claim  17 , wherein the grease composition comprises a urea compound incorporated therein as a thickening agent and comprises at least one rust preventive selected from the group consisting of naphthenate and succinate incorporated therein in an amount of from 0.1 to 10% by weight based on the total amount of the grease.  
     
     
         22 . The rolling bearing as defined in claim  17 , wherein the grease composition comprises a urea compound incorporated therein as a thickening agent and comprises an organic metal salt incorporated therein in an amount of from 0.1 to 10% by weight based on the total amount of the grease.  
     
     
         23 . The rolling bearing as defined in  claim 1 , wherein the urea grease comprises at least one selected from the group consisting of synthetic hydrocarbon oil, ether-based synthetic oil and ester-based synthetic oil incorporated therein as a base oil and comprises a urea compound incorporated therein as a thickening agent and additives free of metal elements other than metal elements which are unavoidable impurities in an amount of from 8 to 40% by weight and from 0.1 to 4% by weight based on the total amount of the grease, respectively.  
     
     
         24 . The rolling bearing as defined in  claim 23 , wherein the content of the additives is from 0.1 to 1% by weight based on the total amount of the grease.  
     
     
         25 . The rolling bearing as defined in  claim 23 , wherein the total content of the metal elements as unavoidable impurities in the additives is not greater than 0.1 ppm based on the total amount of the grease.  
     
     
         26 - 27 . (canceled)  
     
     
         28 . The rolling bearing as defined in claim  26 , wherein the thickening agent incorporated in the grease is made of a urea compound and accounts for from 15 to 40% by weight of the total amount of the grease.  
     
     
         29 - 31 . (canceled)  
     
     
         32 . The rolling bearing as defined in claim  30 , wherein as the thickening agent there is incorporated a urea compound in an amount of from 3 to 35% by weight based on the total amount of the grease.  
     
     
         33 - 43 . (canceled)