Automatic transmission fluid composition
AssigneeNippon Oil Co., Ltd.
InventorMasanobu Kitanaka
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Abstract
An automatic transmission fluid composition is provided which has significantly higher coefficients of dynamic friction (.mu.d) and static friction (.mu.s) than those of the conventional automatic transmission fluid. In addition, the composition has a .mu.o/.mu.d ratio close to 1.0, and a small change with the passage of time in frictional properties. The automatic transmission fluid composition comprises 0.01 to 20% by weight of an overbasic oil-soluble metal salt (a) prepared by use of an alkaline-earth metal borate, and 0.01 to 15% by weight of a compound (b) having a long-chain alkyl group and an amino group in the same molecular structure on the basis of the total amount of composition as essential components, the balance being lubricating base oil.
Claims6
A method for the lubrication of an automatic transmission of a motorcar which comprises lubricating the automatic transmission with an automatic transmission fluid comprising, on the basis of the total amount of composition, as essential components, 0.01 to 20% by weight of an overbasic oil-soluble metal salt (a) prepared by use of an alkaline-earth metal borate, and 0.01 to 15% by weight of a compound (b) derived from a polyolelfin having a molecular weight of 300 to 3000, said compound (b) having a long-chain alkyl group and an amino group in the same molecular structure selected from the group consisting of succinimide and derivatives thereof, benzylamine, polyalkylamine, and polyoxyalkylane aminoamide, the balance being lubricating base oil.
Dependencies are inferred from the claim text.