Abstract: A lubricating oil composition containing a base oil having a kinematic viscosity at 40 degrees C. in a range from 10 mm2/s to 1000 mm2/s with: (A) at least one of phosphorus compounds represented by a formula (1) in an amount of 0.001 mass % to 0.3 mass % in terms of a phosphorus content; (B) at least one of a sulfur compound represented by a formula (2) and a sulfur compound that comprises a dithio (—S—S—) bond in a molecule in an amount of 0.01 mass % to 0.5 mass % in terms of a sulfur content, the latter sulfur compound, when added to the base oil in an amount of 1 mass %, leading to a rating of 2 or lower in a copper strip corrosion test; and (D) a succinimide derivative in an amount of 0.01 mass % to 1 mass %.

Abstract: A lubricating oil composition contains a base oil, (A) a phosphate, (B) a thiophosphate and (C) a naphthylamine derivative. The lubricating oil composition is excellent in wear resistance and is unlikely to generate sludge even at a high temperature, and thus is suitable for an oil-impregnated bearing of a high-speed spindle motor provided to DVD-RAM, Blu-ray disc or the like.

Abstract: A lubricating oil composition containing a base oil having a kinematic viscosity at 40 degrees C. in a range from 10 mm2/s to 1000 mm2/s with: (A) at least one of phosphorus compounds represented by a formula (1) in an amount of 0.001 mass % to 0.3 mass % in terms of a phosphorus content; (B) at least one of a sulfur compound represented by a formula (2) and a sulfur compound that comprises a dithio (—S—S—) bond in a molecule in an amount of 0.01 mass % to 0.5 mass % in terms of a sulfur content, the latter sulfur compound, when added to the base oil in an amount of 1 mass %, leading to a rating of 2 or lower in a copper strip corrosion test; and (D) a succinimide derivative in an amount of 0.01 mass % to 1 mass %.