| abstract |
A lubricant oil composition which comprises a lubricant oil base oil, (1) a polymethacrylate and/or an olefin copolymer each having a mass average molecular weight of 100,000 to 600,000 inclusive and (2) an ester-type ashless friction modifier and/or an amine-type ashless friction modifier, and which has a shear viscosity of 2.3 mPa·s or more and less than 3.7 mPa·s at 150°C. It becomes possible to provide a lubricant oil composition suitable for the reduction of friction in a sliding mechanism, which is equipped with a piston ring and a liner, in a device equipped with the sliding mechanism. |