Lubricant compositions for an automatic transmission

Abstract

The invention provides a lubricant composition for automatic transmissions excellent in sustainability of anti-shudder property, low-temperature viscosity characteristics, and oxidation stability, and excellent and well-balanced in durability of friction characteristics, energy-conserving performance, and anti-fatigue performance on gears. The composition contains a base oil having a kinematic viscosity at 100 DEG C. of 3.7-4.1 mm<2> / s, and composed of base oil having the viscosity of 2.5-4.5 mm<2> / s, and base oil having the viscosity of 10-40 mm<2> / s; 1-20 mass % poly(meth)acrylate viscosity index improver having Mw of 15000-300.00; 2-4 mass % imide friction modifier having a C8-C30 hydrocarbon group; 0.01-0.04 mass % phosphorus extreme pressure agent in terms of phosphorus; and 0.01-0.04 mass % ashless dispersant having at least one alkyl or alkenyl group of a number average molecular weight of >=2000 in terms of nitrogen, all with respect to the total amount of the composition, and has the viscosity of 5.6-5.8 mm<2> / s.

Description

Technical field [0001] The present invention relates to a lubricating oil composition for automatic transmissions, in particular to a long fatigue life even at low viscosity, and excellent overall performance in terms of anti-shake maintenance performance, low-temperature viscosity characteristics, oxidation stability, and anti-friction characteristics. It is well-balanced and is suitable for the lubricating oil composition for automobile automatic transmission. Background technique [0002] In recent years, based on environmental protection issues such as carbon dioxide emission reduction, the energy saving of automobiles, that is, fuel consumption has become a top priority, and the improvement of engines or automatic transmissions is strongly required to contribute to energy conservation. Therefore, the lubricating oil used in these products is required to reduce the stirring resistance or friction resistance more than before. [0003] As a measure to save fuel consumption in a...

AI Technical Summary

Problems solved by technology

However, any such lubricating oil composition is excellent in anti-shake maintenance performance, low-temperature viscosity characteristics, and oxidation stability, but can achieve a transmission that is excellent in performance such as anti-friction characteristics, fuel-saving characteristics, and gear fatigue resistance characteristics. The oil is really rare, still looking forward to further improvement

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