Lubricant composition and bearing

Abstract

There are provided a lubricant composition for use in a ball-and-roller bearing with a smaller diameter, and a ball-and-roller bearing with a smaller diameter. The lubricant composition comprises a base oil comprising a non-ester oil containing a synthesized hydrocarbon oil, and a thickener comprising a urea compound; wherein the urea compound is represented by the formula (I): R 1 —(NHCONH—R 2 )n  (I) where R 1 is a group containing an aromatic hydrocarbon, R 2 is at least one hydrocarbon group selected from the group consisting of an alicyclic hydrocarbon group having 6 to 12 carbon atoms and an aliphatic hydrocarbon group having 6 to 20 carbon atoms, and n is 2 or 3; wherein the synthesized hydrocarbon oil has kinetic viscosity of 20 mm 2 /s or more and less than 80 mm 2 /s at 40° C.; and wherein the base oil comprises 50% by weight or more of the synthesized hydrocarbon oil based on the total weight of the base oil.

What is claimed is:  
     
         1 . A lubricant composition, comprising: a base oil comprising a non-ester oil containing a synthesized hydrocarbon oil, and a thickener comprising a urea compound; 
 wherein the urea compound is represented by the formula (I):    R 1 —(NHCONH—R 2 ) n   (I)   where R 1  is a group containing an aromatic hydrocarbon, R 2  is at least one hydrocarbon group selected from the group consisting of an alicyclic hydrocarbon group having 6 to 12 carbon atoms and an aliphatic hydrocarbon group having 6 to 20 carbon atoms, and n is 2 or 3;    wherein the synthesized hydrocarbon oil has kinetic viscosity of 20 mm 2 /s or more and less than 80 mm 2 /s at 40° C.; and    wherein the base oil comprises 50% by weight or more of the synthesized hydrocarbon oil based on the total weight of the base oil.    
     
     
         2 . The lubricant composition as claimed in  claim 1 , wherein the synthesized hydrocarbon oil is at least one selected from the group consisting of an aliphatic hydrocarbon oil and an aromatic hydrocarbon oil.  
     
     
         3 . The lubricant composition as claimed in  claim 1 , wherein the synthesized hydrocarbon oil is an aliphatic hydrocarbon oil.  
     
     
         4 . The lubricant composition as claimed in  claim 3 , wherein the aliphatic hydrocarbon oil is at least one selected from the group consisting of poly-α-olefine oil and a copolymer of α-olefine and olefine.  
     
     
         5 . The lubricant composition as claimed in  claim 1 , wherein the synthesized hydrocarbon oil is mixed with at least one hydrocarbon oil selected from the group consisting of a mineral oil such as naphthene, paraffin, liquid paraffin, and hydrodewaxed oil; a polyglycol oil such as polyalkylene glycol; an ether oil such as alkyldiphenyl ether, and polyphenyl ether; and a silicone oil such as polydimethyl siloxane, and polyphenyl methyl siloxane.  
     
     
         6 . The lubricant composition as claimed in  claim 5 , wherein the synthesized hydrocarbon oil is the ether oil.  
     
     
         7 . The lubricant composition as claimed in  claim 1 , wherein the R 1  has an aromatic single ring, an aromatic condensed ring, an aromatic single ring combined with methylene, cyanuric ring or isocyanuric ring, or an aromatic condensed ring combined with methylene, cyanuric ring or isocyanuric ring.  
     
     
         8 . The lubricant composition as claimed in  claim 7 , wherein the R 1  is a residual group in which an isocyanate group is eliminated from diphenylmethanediisocyanate, tolyleneduisocyanate, or a duisocyanate polymer.  
     
     
         9 . The lubricant composition as claimed in  claim 8 , wherein the R 1  is diphenylmethanediisocyanate or tolylenediisocyanate.  
     
     
         10 . The lubricant composition as claimed in  claim 1 , wherein the urea compound is a reaction product of at least one disocyanate selected from the group consisting of diphenylmethanediisocyanate and tolylenedusocyanate, and at least one amine compound selected from the group consisting of octylamine, cyclohexylamine, and toluidine.  
     
     
         11 . The lubricant composition as claimed in  claim 1 , having worked penetration of 220 to 280.  
     
     
         12 . A ball-and-roller bearing with a smaller diameter prelubricating a lubricant composition, wherein the lubricant composition comprises a base oil comprising a non-ester oil containing a synthesized hydrocarbon oil, and a thickener comprising a urea compound; 
 wherein the urea compound is represented by the formula (I):    R 1 —(NHCONH—R 2 ) n   (I)   where R 1  is a group containing an aromatic hydrocarbon, R 2  is at least one hydrocarbon group selected from the group consisting of an alicyclic hydrocarbon group having 6 to 12 carbon atoms and an aliphatic hydrocarbon group having 6 to 20 carbon atoms, and n is 2 or 3;    wherein the synthesized hydrocarbon oil has kinetic viscosity of 20 mm 2 /s or more and less than 80 mm 2 /s at 40° C.; and    wherein the base oil comprises 50% by weight or more of the synthesized hydrocarbon oil based on the total weight of the base oil.    
     
     
         13 . The ball-and-roller bearing as claimed in  claim 12 , which is noise resistant and fretting corrosion resistant.  
     
     
         14 . The ball-and-roller bearing as claimed in  claim 12 , which is a spindle bearing for use in an apparatus for recording and reading information.