| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject composition excellent in oxidation stability, etc., by adding a specific organic dithiophosphoric acid zinc salt, a salicylic acid alkaline earth metal salt and a boron-containing alkenyl succinic acid imide having a specific atom composition as essential components to a lubricating oil component. SOLUTION: This lubricating oil composition is obtained by adding (A) an organic dithiophosphoric acid zinc salt having a 5-20C secondary hydrocarbon group, (B) a salicylic acid alkaline earth metal salt and (C) a boron-containing alkenylsuccinic acid imide having a boron/nitrogen atom number ratio of 0.2-0.4 as essential components to a lubricating base oil. The components A, B and C are preferably added in amounts of 0.04-0.2wt.% (as a phosphorus content), 0.05-2wt.% (as a metal content) and 0.005-0.4wt.% (as a nitrogen content), respectively, based on the whole amount of the lubricating oil composition. |
