Patent ID: 8518864

Claim:
A grease composition for constant-velocity joints comprising: (a) mineral oil as a base oil, (b) a diurea thickener represented by the following formula (1): R 1 NH—CO—NH—C 6 H 4 - p -CH 2 —C 6 H 4 - p -NH—CO—NHR 1′ (1) wherein R 1 and R 1′ are independently C8-C20 alkyl, (c) a zinc dialkyldithiophosphate represented by the following formula (2): [(R 2 O) 2 SP—S] 2 —Zn (2) wherein R 2 is a primary or secondary C3-C8 alkyl, (d) a sulfurized molybdenum dialkyldithiocarbamate represented by the following formula (3): [(R 3 2 N—CS—S] 2 —Mo 2 O m S n (3) wherein R 3 is a primary or secondary C3-C18 alkyl, m is 0 to 3, n is 1 to 4 and m+n=4, (e) a zinc dialkyldithiocarbamate represented by the following formula (4): [(R 4 2 N—CS—S] 2 —Zn (3) wherein R 4 is a primary or secondary C3-C8 alkyl, and (f) a sulfur-nitrogen extreme pressure additive other than (c) to (e) above, wherein said (b) diurea thickener is contained in an amount of 2 to 20% by mass, which makes a consistency of the grease composition within a range of 285 to 340, said (c) zinc dialkyldithiophosphate is contained in an amount of 0.1 to 5% by mass, said (d) sulfurized molybdenum dialkyldithiocarbamate is contained in an amount of 0.1 to 5% by mass, said (e) zinc dialkyldithiocarbamate is contained in an amount of 1 to 5% by mass, and wherein said (f) sulfur-nitrogen extreme pressure additive is contained in an amount of 0.05 to 3% by mass, all mass percents being based on the total amount of the composition.