Grease Composition For Constant Velocity Joints

Abstract

The present invention provides a grease composition for use in constant velocity joints, having improved wear resistance and endurance characteristics. The grease is made by incorporating in a urea grease (A) a molybdenum dialkyldithiocarbamate, (B) a molybdenum dithiophosphate, (C) 2-(4-morpholinyldithio)benzothiazole and (D) a calcium sulphonate. The blended amount of (A)+(B) is made not more than 10% by weight, and that of (C) and (D) not more than 3% by weight respectively. Also, a grease for use in constant velocity joints is made by further adding (E) zinc dithiophosphate to the aforementioned components (A)+(B)+(C)+(D) in a blended amount of not more than 3% by weight.

1 . A grease composition for use in constant velocity joints, wherein a urea grease constituted from a base oil and a urea compound is blended with:
 (A) a molybdenum dialkyldithiocarbamate as represented by the undermentioned formula (I)   
     
       
         
         
             
             
         
       
       (where R denotes an alkyl group of 1˜24 carbons) and 
       (B) at least one kind of a molybdenum dialkyldithiophosphate or a molybdenum diaryldithiophosphate as represented by the undermentioned formula (II) 
     
     
       
         
         
             
             
         
       
       (where R is a primary or secondary alkyl group or an aryl group), the blended amount of (A) and (B) being not more than 10% by weight, and 
       (C) not more than 3% by weight of 2-(4-morpholinyidithio)benzothiazole as represented by the undermentioned formula (III) 
     
     
       
         
         
             
             
         
       
       and (D) not more than 3% by weight of a calcium sulphonate. 
     
   
   
       2 . The grease composition for use in constant velocity joints in accordance with  claim 1  characterised in that at least one kind of a zinc dialkyldithiophosphate or a zinc diaryldithiophosphate as represented by the undermentioned formula IV 
     
       
         
         
             
             
         
       
       (where R′ is a primary or secondary alky group or an aryl group) is further incorporated in the amount of not more than 3% by weight. 
     
   
   
       3 . Use of the grease composition according to  claim 1  in constant velocity joints. 
   
   
       4 . Use of the grease composition according to  claim 2  in constant velocity joints.