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US 12,680,047 B2Granted
Ball screw grease composition for rack-assisted electric power steering
AssigneeKyodo Yushi Co., Ltd.
InventorsMinami Soma, Tsuyoshi Kochi, Tomonobu Komoriya
Life of this patent
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Abstract
A ball screw grease composition for a rack-assisted electric power steering contains a thickener, a base oil, and at least one compound selected from the group consisting of a Ca sulfonates, fatty acids, and triglycerides, wherein the kinematic viscosity of the base oil at 40° C. is 4-100 mm2/s, and the worked penetration of the composition is 265-385.
Claims13
A method for lubricating a ball screw part of rack-assisted electric power steering, comprising:
- applying a grease composition to the ball screw part of rack-assisted electric power steering,
- wherein the grease composition comprises:
- a thickener;
- a base oil;
- and
- at least one compound selected from the group consisting of a Ca sulfonate, and a triglyceride, wherein
- the thickener is represented by formula (I):
- R1—NHCONH—R2—NHCONH—R3 (I)
- wherein R1 and R3 may be the same or different, and each represent a straight chain saturated alkyl group having 8 to 20 carbon atoms or a cyclohexyl group, and R2 is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms,
- the base oil contains poly-α-olefin,
- a kinematic viscosity at 40° C. of the base oil is 4 to 100 mm2/s, and
- a worked penetration of the composition is 265 to 385.
9 more elements
A method for suppressing torque variation at a ball screw part of rack-assisted electric power steering, comprising:
- applying a grease composition to the ball screw part of rack-assisted electric power steering,
- wherein the grease composition comprises:
- a thickener,
- a base oil;
- and
- at least one compound selected from the group consisting of a Ca sulfonate, and a triglyceride, wherein
- the thickener is represented by formula (I):
- R1—NHCONH—R2—NHCONH—R3 (I)
- wherein R1 and R3 may be the same or different, and each represent a straight chain saturated alkyl group having 8 to 20 carbon atoms or a cyclohexyl group, and R2 is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms,
- the base oil contains poly-α-olefin,
- a kinematic viscosity at 40° C. of the base oil is 4 to 100 mm2/s, and
- a worked penetration of the composition is 265 to 385.
9 more elements
Dependencies are inferred from the claim text.