Toyota Jidosha Kabushiki Kaisha

Shell Oil Comapny

Shell Lubricants Japan K.k.

Shell Internationale Research Maatschappij, B.v.

Keiichi Moriki

Kenji Ueno

Takatoshi Shinyoshi

Eiji Nagatomi

Mitsuhiro Nagakari

Koji Saito

Kiyonari Ishikawa

Misato Kishi

Ryuji Maruyama

Kenji Ohara

Kotaro Hiraga

Hiroshi Fujito

Yoshiharu Baba

Minoru Saitou

The purpose of the present invention is to provide a lubricant composition which can be applied as a gear oil for a high-output and high-speed gear mechanism, and whereby fuel saving as well as further wear resistance in a bearing of a pinion gear can be realized while maintaining excellent durability, seizure resistance, and stability are maintained. A lubricant composition containing a Fischer-Tropsch-derived base oil, a poly alpha-olefin, and an ester compound, and further containing an unsaturated fatty acid and/or a partial ester compound of an unsaturated fatty acid and a polyol, wherein the partial ester compound of an unsaturated fatty acid includes a monoester compound of an unsaturated fatty acid and a polyol in a ratio of 50% by mass with respect to the total amount of the partial ester compound, and the SAE viscosity grade of the lubricant composition is 75W-85 or lower.

Lubricant composition

The present invention provides a lubricating oil composition comprising a mixture of both a poly-alpha-olefin and an ester compound, the lubricating oil composition having an SAE viscosity grade of 75W-85, satisfying GL-5 in terms of API gear oil designation and having a viscosity index of 160 or more. The above mixture of the poly-alpha-olefin and ester compound is preferably contained in an amount of from 75 to 90 wt % with reference to the total amount of the lubricating oil composition. The poly-alpha-olefin is preferably a mixture of a poly-alpha-olefin having low viscosity of from about 3 to 6 mm/s at 100&#xb0; C. and a poly-alpha-olefin having high viscosity of from about 35 to 45 mm/s at 100&#xb0; C.

Lubricating oil composition

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Tokyo, Japan

Keiichi Moriki