Lubricating oil composition

Abstract

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 about3 to 6 mm<2> / s at 100 DEG C and a poly-alpha-olefin having high viscosity of from about 35 to 45 mm<2> / s at 100 DEG C.

Description

technical field [0001] This invention relates to lubricating oil compositions, and in particular to lubricating oil compositions useful as automotive gear oils or automotive hypoid gear oils. Background technique [0002] In recent years, for the load-bearing performance required in automotive gear oils, as a result of increased automotive power, standards of GL-4 to GL-5 named by API (American Petroleum Institute) for gear oils are being demanded . [0003] In gear oils that are required to have such durability, for the purpose of maintaining an oil film on the gear tooth surface, viscosity No. 90 (13.5-24.0 mm) defined by SAE (Society of Automotive Engineers) is generally used. 2 / s(100℃)) oil. [0004] But on the other hand, it is also necessary to save fuel consumption; in order to achieve this, it is necessary to reduce the stirring resistance; and in order to achieve this, it is necessary to obtain low viscosity. [0005] In order to meet these requirements at the s...

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Problems solved by technology

[0004] But on the other hand, it is also necessary to save fuel consumption; in order to achieve this purpose, the stirring resistance must be reduced; and in order to achieve this purpose, it is necessary to obtain low viscosity

[0005] In order to meet these requirements at the same time, that is, to maintain the effect of forming an oil film on the gear tooth surface and to obtain low viscosity, if the conventional technique of increasing the amount of extreme pressure additive added to the low viscosity base oil is adopted, there is phosphorus used as an extreme pressure additive. or sulfur-based additives may increase the negative impact of corrosion of components containing copper components High risk of shortening equipment life

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