GREASE COMPOSITION FOR HUB UNIT BEARING EQUIPPED WITH ANGULAR CONTACT BALL BEARING, AND HUB UNIT BEARING

摘要

Disclosed is a grease composition for a hub unit bearing equipped an angular contact ball bearing, which comprises (a) a thickening agent that is a mixture of diurea compounds respectively represented by the following formulae (I) to (III): (I) R1-NHCONH-R2-NHCONH-R1, (II): R1-NHCONH-R2-NHCONH-R3 and (III): R3-NHCONH-R2-NHCONH-R3 (wherein R1 represents a cyclohexyl group, R2 represents a C6-15 bivalent aromatic hydrocarbon group; and R3 represents a C12-20 linear or branched alkyl group, wherein {R1/(R1+R3)}×100 = 85 to 95 mol%), (b) a base oil, (c) a molybdenum dialkyldithiocarbamate, and (d) calcium sulfonate. The grease composition can reduce the leakage of a grease in a hub unit bearing and has excellent peeling resistance and an excellent bearing lubrication life.