Grease composition for ball type constant velocity joints and ball type constant velocity joints containing the grease composition

Abstract

A grease composition for use in ball type constant velocity joints, which comprises the following components a base oil; a diurea thickener of the formula: R 1 —NH—CO—NH—C 6 H 4 -p-CH 2 —C 6 H 4 -p-NH—CO—NHR 2 wherein R 1 and R 2 are alkyl groups having 8 carbon atoms, molybdenum disulfide; molybdenum dithiocarbamate of the formula: (R 3 R 4 N—CS—S) 2 —Mo 2 OmSn wherein R 3 and R 4 independently represent an alkyl group having 1 to 24 carbon atoms, m is 0 to 3, n is 4 to 1 and m+n=4, calcium salts or overbasic calcium salts of petroleum sulfonates, sulfur-phosphorus extreme pressure agent, and castor oil. The grease composition exhibits excellent wear-resistance and pitting-inhibitory effect.

1 . A grease composition for use in ball type constant velocity joints, which comprises the following components: 
 (a) a base oil selected from the group consisting of mineral oils, ether type synthetic oils, ester type synthetic oils, hydrocarbon type synthetic oils and mixture thereof,    (b) a diurea thickener represented by the following formula:      R 1 -NH-CO-NH-C 6  H 4 -p-CH 2 -C 6  H 4 -p-NH-CO-NHR2    wherein R 1  and R 2  are alkyl groups having 8 carbon atoms,    (c) molybdenum disulfide;    (d) a molybdenum dithiocarbamate represented by the following formula:      (R 3 R 4 N-CS-S) 2 -Mo 2 OmSn    wherein R 3  and R 4  independently represent alkyl groups having 1 to 24 carbon atoms, m is 0 to 3, n is 4 to 1 and m+n=4,    (e) at least one calcium salt selected from the group consisting of calcium salts of petroleum sulfonates, and overbasic calcium salts of petroleum sulfonates,    (f) a sulfur-phosphorus extreme pressure agent in an amount of 1.5 to 10% by weight on the basis of the total weight of the composition, and    (g) vegetable fats and oils.    
   
   
       2 . The grease composition of  claim 1 , wherein the grease composition is for use in high contact pressure ball type constant velocity joints.  
   
   
       3 . The grease composition of  claim 1 , wherein the grease composition comprises, on the basis of the total weight of the composition, 1 to 25% by weight of the diurea thickener; 0.1 to 5.0% by weight of the molybdenum disulfide; 0.1 to 5.0% by weight of the molybdenum dithiocarbamate; 0.1 to 5.0% by weight of the calciumd salt; 1.5 to 10% by weight of the sulfur-phosphorus extreme pressure agent, and 0.1 to 3.0% by weight of the vegetable fats and oils.  
   
   
       4 . The grease composition of  claim 1 , wherein the grease composition comprises, 2.0 to 5.0% by weight of the sulfur-phosphorus extreme pressure agent.  
   
   
       5 . The grease composition of  claim 1 , wherein the grease composition is for use in the ball type fixed constant velocity joints.  
   
   
       6 . A ball type constant velocity joint, wherein the grease composition of  claim 1  is contained.  
   
   
       7 . A ball type constant velocity joint, wherein the grease composition of  claim 3  is contained.  
   
   
       8 . A ball type constant velocity joint, wherein the grease composition of  claim 4  is contained.