| abstract |
The present invention provides a grease composition for an EV/HEV drive motor bearing, the composition containing: a diurea thickener of formula (A) as well as a base oil containing at least 80 mass% of trimethylolpropane ester oil per the total mass of base oil, the dynamic viscosity of the base oil at 40°C being 15 to 50 mm 2 /s. (In the formula, R 2 represents a C 6-15 divalent aromatic hydrocarbon group. R 1 and R 3 are the same or different groups, and represent a C 16-20 linear or branched alkyl group or cyclohexyl group, the proportion of the number of moles of the C 16-20 linear or branched alkyl group relative to the sum of the numbers of moles of the C 16-20 linear or branched alkyl group and the cyclohexyl group [{(number of alkyl groups)/(number of cyclohexyl groups + number of alkyl groups)} ×100] being 60 to 80%.) This grease composition has a long bearing lubrication lifespan even at high temperature/high speed conditions, and satisfies low-temperature fluidity. |