LUBRICATING OIL COMPOSITION CONTAINING HYDRATED ALKALI METAL BORATE WITH IMPROVED FRICTIONAL CHARACTERISTIC

摘要

PROBLEM TO BE SOLVED: To provide a lubricating oil composition with improved frictional and wear performance. SOLUTION: The lubricating oil composition, improved in frictional and wear performance especially when the ratio of polysulfide is controlled, comprises a major amount of an oil of lubricating viscosity; at least one alkali metal borate; at least one dihydrocarbyl polysulfide component comprising a mixture of sulfides and having at least 30% dihydrocarbyl tetrasulfide or higher sulfides; at least one non-acidic phosphorous component comprising a trihydrocarbyl phosphite; at least one dihydrocarbyl dithiophosphate; and a phosphorous component comprising a dihydrocarbyl phosphite component. COPYRIGHT: (C)2009,JPO&INPIT