Low viscosity lubricating fluid for an electric motor system
AssigneeAfton Chemical Corporation
InventorSusie Hurley
Life of this patent
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Abstract
An electric motor lubricating fluid for an electric motor system including a lubricating base oil, at least one sulfurized component, at least two phosphorus-providing additives, and at least one high molecular weight dispersant. The electric motor lubricating fluid provides acceptable wear performance as well as good electrical conductivity and oxidative stability for use in electric motor system fluids having a low viscosity.
Claims27
An electric motor lubricating fluid suitable for electric or hybrid-electric vehicles, the electric motor lubricating fluid comprising:
- one or more base oils of lubricating viscosity;
- about 2 to about 4 weight percent of a succinimide dispersant derived from a high-molecular weight polyisobutylene having a number average molecular weight of about 2,000 or greater;
- an amine salt of a phosphoric acid ester providing about 40 to about 70 ppm of phosphorus to the electric motor lubricating fluid;
- an oil-soluble phosphorus antiwear additive including an ashless dialkyl dithiophosphate providing about 40 to about 70 ppm of phosphorus to the electric motor lubricating fluid;
- a sulfur-providing additive including a thiadiazole or derivative thereof providing up to 950 ppm of sulfur to the electric motor lubricating fluid;
- and
- wherein the electric motor lubricating fluid has a kV 100° C. of about 4.5 cSt or less and, about 150 to about 250 ppm of total phosphorus.
An additive concentrate suitable for an electric motor lubricating fluid, the additive concentrate comprising:
- about 40 to about 70 weight percent of a succinimide dispersant derived from a high molecular weight polyisobutylene having a number average molecular weight of about 2,000 or greater;
- an amine salt of a phosphoric acid ester providing about 1000 to about 1500 ppm of phosphorus to the additive concentrate;
- an oil-soluble phosphorus antiwear additive including an ashless dialkyl dithiophosphate providing about 800 ppm to about 1300 ppm of phosphorus to the additive concentrate;
- a sulfur-providing additive including a thiadiazole or derivative thereof providing sulfur, but no more than about 18,000 ppm of sulfur to the additive concentrate;
- and
- wherein the additive concentrate has a kV 100° C. of about 15 cSt to about 80 sCt.
A method for lubricating a driveline component including an electric motor, the method comprising:
- lubricating the driveline component with an electric motor lubricating composition and wherein the electric motor lubricating composition contacts portions of the electric motor;
- the electric motor lubricating composition including (i) one or more base oils of lubricating viscosity;
- (ii) about 2 to about 4 weight percent of a succinimide dispersant derived from a high molecular weight polyisobutylene having a number average molecular weight of about 2,000 or greater;
- (iii) an amine salt of a phosphoric acid ester providing about 40 to about 70 ppm of phosphorus to the electric motor lubricating fluid;
- (iv) an oil-soluble phosphorus antiwear additive including an ashless dialkyl dithiophosphate providing about 40 to about 70 ppm of phosphorus to the electric motor lubricating fluid;
- and (v) a sulfur-providing additive including a thiadiazole or derivative thereof providing sulfur, but no more than about 950 ppm of sulfur to the electric motor lubricating fluid;
- and
- wherein the electric motor lubricating fluid has a kV 100° C. of about 3.5 cSt or less, about 150 to about 200 ppm of total phosphorus, and an electrical conductivity of about 37 nS/M or less, as measured by a modified conductivity test pursuant to ASTM D2624-15 using the electric motor lubricating fluid and measured at 20 Hz and at 100° C.
Dependencies are inferred from the claim text.