Grease compositions for constant velocity joints and constant velocity joints

Abstract

The invention provides a grease composition for constant velocity joints and constant velocity joints in which the grease composition is packed. The composition comprises (a) a base oil comprising a synthetic oil; (b) a thickening agent; (c) a molybdenum sulfurized dialkyl dithiocarbamate; (d) a thiophosphate; and (e) a zinc sulfurized dialkyl dithiocarbamate. The composition can reduce low temperature rotational torque and folding torque in constant velocity joints while inhibiting deterioration of a boot material comprising a silicone rubber.

1 . A grease composition for constant velocity joints, which comprises the following components (a) to (e):
 (a) a base oil comprising a synthetic oil;   (b) a thickening agent;   (c) a molybdenum sulfurized dialkyl dithiocarbamate;   (d) a thiophosphate; and   (e) a zinc sulfurized dialkyl dithiocarbamate.   
     
     
         2 . The grease composition for constant velocity joints of  claim 1 , wherein the composition further comprises (f) a mixture of 30-70% by mass of molybdenum disulfide and 70-30% by mass of a fatty acid amide. 
     
     
         3 . The grease composition for constant velocity joints of  claim 1 , wherein the synthetic oil in Component (a) is a synthetic hydrocarbon oil. 
     
     
         4 . The grease composition for constant velocity joints of  claim 1 , wherein Component (b): the thickening agent is a urea compound. 
     
     
         5 . The grease composition for constant velocity joints of  claim 1 , wherein the content of Component (c): the molybdenum sulfurized dialkyl dithiocarbamate is 0.1 to 10% by mass based on the total mass of the grease composition. 
     
     
         6 . The grease composition for constant velocity joints of  claim 1 , wherein the content of Component (d): the thiophosphate is 0.1 to 10% by mass based on the total mass of the grease composition. 
     
     
         7 . The grease composition for constant velocity joints of  claim 1 , wherein the content of Component (e): the zinc sulfurized dialkyl dithiocarbamate is 0.1 to 10% by mass based on the total mass of the grease composition. 
     
     
         8 . The grease composition for constant velocity joints of  claim 2 , wherein the content of Component (f): the mixture of 30-70% by mass of molybdenum disulfide and 70-30% by mass of a fatty acid amide is 0.1 to 10% by mass based on the total mass of the grease composition. 
     
     
         9 . A constant velocity joint in which the grease composition of  claim 1  is packed.