| 摘要 |
PURPOSE: To provide an oil composition for automatic transmission improved in stability to oxidation that has an excellent judder vibration preventive function which will not be diminished even when the composition is used for a long period of time by adding prescribed amounts of a specified thiophosphite compound, a specified organic metal salt, and a specified polyamide compound to a base oil. CONSTITUTION: To a base oil (e.g. a paraffin mineral oil) are added 0.1 to 5wt.% thiophosphite compound of formula I wherein R<1> denotes a hydrocarbon group having 6 to 18 carbon atoms, 0.02 to 1wt.% one or more compounds selected from among organic metal salts consisting of sulfonates, phenates, and salicylates of alkaline earth metals (e.g. a compound of formula II wherein R<2> denotes a 12C alkyl group, R<3-4> each denote H, and M denotes Ca, and 0.01 to 3wt.% polyamide compound of formula III wherein R<5> denotes a 12-50C hydrocarbon group, R<6> denotes OH, H2 N(CH2 )c NH wherein (c) is 2 to 6, R<7> denotes H, HOOC-R<8> -CO wherein R<8> denotes R<5> , (a) is 2 to 6, and (b) is 1 to 10 based on the total weight of the composition. |
