Lubricating oil composition for automatic transmissions

Abstract

The present invention relates to a lubricating oil composition comprising a major amount of base oil of lubricating viscosity and the following additives in the following amounts based on a total amount of the lubricating oil composition: (A) 0.1 to 10 wt.% of a succinic acid ester, (B) 0.01 to 2 wt.% of a phosphorous acid ester, (C) 0.1 to 5 wt.% of an amide compound which is a reaction product obtained by reaction of a linear or branched, saturated or unsaturated monovalent aliphatic acid having 8 to 22 carbon atoms, urea, and polyalkylenepolyamine, (D) 0.0 1 to 2 wt.% of an overbased metal containing detergent, and (E) 0.01 to 1 wt.% of a corrosion inhibitor.

1 . A lubricating oil composition comprising a major amount of base oil of lubricating viscosity and the following additives in the following amounts based on a total amount of the composition: 
 (A) 0.1 to 10 wt. % of a succinic acid ester,    (B) 0.01 to :2 wt. % of a phosphorous acid ester,    (C;) 0.1 to 5 wt. % of an amide compound which is a reaction product obtained by reaction of a linear or branched, saturated or unsaturated monovalent aliphatic acid having 8 to 22 carbon atoms, urea, and polyalkylenepolyamine,    (D) 0.01 to 2 wt. % of an overbased metal-containing detergent, and    (E) 0.01 to 1 wt. % of a corrosion inhibitor.    
     
     
         2 . The lubricating oil composition of  claim 1 , wherein the amide compound is a borated amide compound obtained by borating the reaction product.  
     
     
         3 . The lubricating oil composition of  claim 1  wherein the amide compound is a reaction product obtained by reacting one mole of the linear or branched, saturated or unsaturated monovalent aliphatic acid having 8 to 22 carbon atoms, 0.01 to 2 moles of urea, and 0.1 to 1 mole of polyalkylenepolyamine.  
     
     
         4 . The lubricating oil composition of  claim 1 , wherein the polyalkylenepolyamine contains 2 to 30 carbon atoms and 2 to 15 nitrogen atoms, each of at least two nitrogen atoms forming primary amine.  
     
     
         5 . The lubricating oil composition of  claim 4 , wherein the polyalkylenepolyamine is at least one compound selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexaminne, and hexaethyleneheptamine.  
     
     
         6 . The lubricating oil composition of  claim 5 , wherein the polyalkylenepolyamine is hexaethyleneheptamine.  
     
     
         7 . The lubricating oil composition of  claim 1 , wherein the monovalent aliphatic acid is isostearic acid.  
     
     
         8 . The lubricating oil composition of  claim 1 , wherein the succinic acid ester is an ester derived from a polyol and an alkenyl-substituted succinic an hydride prepared by a reaction between maleic anhydride and polyolefin having a number average molecular weight of 450 to 5,000.  
     
     
         9 . The lubricating oil composition of  claim 8 , wherein the polyolefin is polybutene.  
     
     
         10 . The lubricating oil composition of  claim 9 , wherein the reaction between maleic anhydride and polyolefin is performed by a thermal reaction process utilizing no chlorine.  
     
     
         11 . The lubricating oil composition of  claim 1 , wherein the phosphorous acid ester is diphenyl hydrogen phosphite.  
     
     
         12 . The lubricating oil composition of  claim 1 , wherein the overbased metal-containing detergents is an overbased calcium alkylbenzenesulfonate detergent having a total base number of 10 to 500 mg·KOH/g.  
     
     
         13 . A method for reducing shudder in an automatic transmission of an internal combustion engine, said method comprising adding the lubricating oil composition of  claim 1  to the automatic transmission and operating the engine.