Grease composition and rolling apparatus

Abstract

A grease composition is produced by mixing a thickener comprising a fluoro resin and a second thickener component (a metallic soap, a complex metallic soap, an N-substituted terephthalamic acid metal salt, organic bentonite or a calcium sulfonate complex) into a base oil. This grease composition is excellent in heat resistance, load carrying capacity, water resistance, rust protection, lubricating life and the like. A rolling apparatus filled with the above grease composition has excellent lubricating ability and is long-lived under high-temperature conditions. Moreover, a grease composition is produced by mixing a thickener comprising a fluoro resin and carbon black as a second thickener component into a base oil. This grease composition is excellent in heat resistance, water resistance, rust protection, lubricating life, electric conductivity and the like. A rolling apparatus filled with the above grease composition has excellent electric conductivity and is long-lived under high-temperature conditions.

1 . A grease composition comprising a base oil and a thickener, wherein said thickener comprises a fluoro resin and a second thickener component, wherein said second thickener component is carbon black.  
   
   
       2 . The grease composition according to  claim 1 , wherein said thickener comprises 40 to 80% by mass of the fluoro resin and 60 to 20% by mass of the carbon black.  
   
   
       3 . The grease composition according to  claim 2 , wherein the content of said thickener is 5 to 40% by mass based on the total mass of the composition.  
   
   
       4 . The grease composition according to  claim 2 , wherein said base oil comprises a perfluoropolyether oil and at least one of either a mineral oil or synthetic oil.  
   
   
       5 . The grease composition according to  claim 4 , wherein said base oil comprises 10 to 90% by mass of the perfluoropolyether oil and 90 to 10% by mass of at least one of either the mineral oil or synthetic oil.  
   
   
       6 . The grease composition according to  claim 4 , wherein said perfluoropolyether oil has a kinematic viscosity at 40° C. of 20 to 400 mm 2/s, and at least one of either said mineral oil or synthetic oil has a kinematic viscosity at 40° C. of 20 to 400 mm 2 /s.  
   
   
       7 . The grease composition according to  claim 2 , wherein the DBP oil absorption of said carbon black is 100 ml/100 g or more, the primary particle size is 100 nm or shorter, and the specific surface area is 50 m 2 /g or larger.  
   
   
       8 . The grease composition according to  claim 2 , which comprises an additive, wherein the content of said additive is 20% or less by mass based on the total mass of the composition.  
   
   
       9 . A rolling apparatus comprising an inner member having a raceway surface on the outer surface; an outer member which has a raceway surface opposed to the raceway surface of said inner member and is disposed outside of said inner member; and a plurality of rolling elements which are disposed between said two raceway surfaces so as to flexibly roll therebetween, wherein a space, which is formed between said inner member and said outer member and in which said rolling elements are disposed, is filled with the grease composition according to  claim 1 .  
   
   
       10 . The rolling apparatus according to  claim 9 , which is a rolling bearing used for alternators, electromagnetic clutches or idler pulleys.  
   
   
       11 . The rolling apparatus according to  claim 9 , which is a rolling bearing used for copying machines or printers.