Lubricating oil composition for transmissions

摘要

The present invention provides a lubricating oil composition for transmissions which is improved in fuel saving properties and has excellent metal fatigue prevention properties and heat resistance. The lubricating oil composition comprises (A) a mineral base oil having a 100° C. kinematic viscosity of 1.5 mm2/s or higher and 3.5 mm2/s or lower, a pour point of −25° C. or lower, a viscosity index of 110 or greater, a % CN of 2 or greater and 20 or less and a % CA of 3 or less, the lubricating oil composition having a 100° C. kinematic viscosity of 2.5 mm2/s or higher and 3.8 mm2/s or lower.

主权项

1. A lubricating oil composition for transmissions comprising:
(A) a mineral base oil having a 100° C. kinematic viscosity of 1.5 mm2/s or higher and 3.5 mm2/s or lower, a pour point of −25° C. or lower, a viscosity index of 110 or greater, a % CN of 2 or greater and 20 or less and a % CA of 3 or less, (B) a poly(meth)acrylate comprising at least a structural component derived from a monomer represented by formula (1) in an amount of 0.1 percent by mass or more and 20 percent by mass or less, the lubricating oil composition having a 100° C. kinematic viscosity of 2.5 mm2/s or higher and 3.8 mm2/s or lower: wherein R1 is hydrogen or methyl, and R2 is a hydrocarbon group having 1 to 30 carbon atoms, wherein Component (B) comprises (B-1) a poly(meth)acrylate produced by polymerizing a monomer component comprising (Ba-1) to (Bd-1): 20 to 60 percent by mass of (Ba-1) a (meth)acrylate wherein R2 is an alkyl group having 1 to 4 carbon atoms; 0 to 30 percent by mass of (Bb-1) a (meth)acrylate wherein R2 is an alkyl group having 5 to 10 carbon atoms; 20 to 70 percent by mass of (Bc-1) a (meth)acrylate wherein R2 is an alkyl group having 11 to 18 carbon atoms; and 5 to 50 percent by mass of (Bd-1) a (meth)acrylate wherein R2 is an alkyl group having 19 to 30 carbon atoms.