Nippon Oil Corporation

Petroleum Energy Center

Masaaki Itou

Masato Takahashi

Shigeki Matsui

Takashi Sano

Shozaburo Konishi

Masahiro Taguchi

Shinichi Shirahama

Hitoshi Komatsubara

Osamu Kurosawa

Izuru Sugiura

Hisayuki Wada

Toru Matsuoka

Kai Fu

The lubricating base oil of the invention is characterized by satisfying at least one of the following conditions (a) or (b).

Lubricant base oil, lubricant composition for internal combustion engine and lubricant composition for driving force transmitting device

Lubricating oil compositions for transmissions comprises (A) a lubricating base oil with a kinematic viscosity at 100&#xb0; C. adjusted to 1.5 to 6 mm/s, composed of (A1) a lubricating base oil with a kinematic viscosity at 100&#xb0; C. of 1.5 mm/s or higher and lower than 7 mm/s or (A1) the lubricating oil and (A2) a lubricating base oil with a kinematic viscosity at 100&#xb0; C. of 7 to 50 mm/s, blended with (B) a poly(meth)acrylate-based additive, so that the composition has a kinematic viscosity at 100&#xb0; C. of 3 to 8 mm/s and a viscosity index of 95 to 200, (A) and (B) fulfill a specific requirement. The compositions achieve long fatigue life though having low viscosity.

Lubricating oil composition for transmission

The present invention provides a lubricating oil composition which is less in evaporation loss even having a low viscosity and excellent in lubricating properties such as low-temperature viscosity characteristics and anti-seizure properties and in oxidation stability, suitable for use in engines, automatic transmissions, manual transmissions, final reduction gear units, and continuously variable transmissions. The lubricating oil composition comprises (A) a lubricating base oil and (B) a poly(meth)acrylate additive in such an amount that the kinematic viscosity at 100&#xb0; C. of the composition (Vc) is from 3 to 15 mm/s, the viscosity index of the composition is from 95 to 200, and the ratio of the kinematic viscosity at 100&#xb0; C. of (A) the lubricating base oil (Vb) to (Vc) (=Vb/Vc) is 0.60 or greater, further, (C) a metallic detergent, (D) an ashless dispersant and (E) zinc dithiophosphate, each in a specific amount.

Lubricating oil composition

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Yokohama, Japan

Masaaki Itou