Patent ID: 11214755

Abstract:
A lubricating oil composition including: a lubricating base oil; (A) a poly(meth)acrylate having a weight average molecular weight of no more than 50,000, in an amount of 2 to 10 mass %; (B) a phosphite ester of the general formula (1) in an amount of 0.01 to 0.06 mass % in terms of P; (C) a thiadiazole compound in an amount of 0.01 to 0.2 mass %; and (D) a Ca salicylate detergent in an amount of 0.005 to 0.03 mass % in terms of Ca, wherein the lubricating oil composition has a kinematic viscosity at 40° C. of 4.0 to 20.0 mm2/s, and a kinematic viscosity at 100° C. of 1.8 to 5.2 mm2/s; and has a ratio [S]/[P] of 2.2 to 4.0, wherein the [S] represents a sulfur content, and the [P] represents a phosphorus content: wherein R1 and R2 are each independently a group having 5 to 20 carbons represented by the general formula (2); and  wherein R3 is a C2-17 linear chain hydrocarbon group, and R4 is a C2-17 linear chain hydrocarbon group.