| 摘要 |
PROBLEM TO BE SOLVED: To provide a lubricating oil composition for automatic variable-speed gear, excellent in shudder inhibition-maintaining performance, low-temperature viscosity and oxidation stability, good in balance between all of friction property durability, fuel economy and gear service life, and having a combination of fuel economy performance and gear service life suitable for automotive use in particular. SOLUTION: The lubricating oil composition for automatic variable-speed gear, 5.6-5.8 mm<SP>2</SP>/s in dynamic viscosity at 100°C, is obtained by compounding a base oil 3.7-4.1 mm<SP>2</SP>/s in dynamic viscosity at 100°C comprising a base oil 2.5-4.5 mm<SP>2</SP>/s in dynamic viscosity at 100°C and a base oil 10-40 mm<SP>2</SP>/s in dynamic viscosity at 100°C with 1-20 mass%, based on the total amount of the composition, of a poly(meth)acrylate-based viscosity index improver 15,000-30,000 in Mw(weight-average molecular weight), 2-4 mass%, based on the total amount of the composition, of an imide-based friction regulator having 8-30C hydrocarbon group, 0.01-0.04 mass%, based on the total amount of the composition, of a phosphorus-based extreme-pressure agent, and 0.01-0.04 mass%, based on the total amount of the composition and in terms of a nitrogen content, of an ashless dispersant 2,000 or higher in number-average molecular weight having at least alkyl or alkenyl group. COPYRIGHT: (C)2008,JPO&INPIT |
