Grease composition and grease-filled wheel bearing

Patent metadata

Field	Value
Publication number	US-10584750-B2
Application number	US-201515125439-A
Country	US
Kind code	B2
Filing date	Mar 12, 2015
Priority date	Mar 12, 2014
Publication date	Mar 10, 2020
Grant date	Mar 10, 2020

Abstract

Provided is a grease composition for a wheel bearing, containing (a) a base oil consisting of a mineral oil and a synthetic hydrocarbon oil, wherein the ratio of the synthetic hydrocarbon oil to the total amount of the mineral oil and the synthetic hydrocarbon oil is 40 to 60 mass %, and the base oil has a kinematic viscosity at 40° C. of 40 to 65 mm 2 /s; (b) a thickener of formula (A) wherein R 2 is diphenylmethane, and R 1 and R 3 , which may be the same or different from each other, each represent cyclohexyl group or a straight-chain or branched alkyl group having 16 to 20 carbon atoms, with a molar ratio of the cyclohexyl group to the total number of moles of the cyclohexyl group and the alkyl group being 50 to 90 mol %; (c) an amine type antioxidant; and (d) an amine phosphate type antiwear agent.

First claim

The invention claimed is:

1. A grease composition for a wheel bearing, comprising;
(a) a base oil consisting of a mineral oil and poly-alpha-olefin, wherein an amount of the poly-alpha-olefin to a total amount of the mineral oil and the poly-alpha-olefin is 40 to 60 mass %, the base oil has a kinematic viscosity at 40° C. of 40 to 65 mm 2 /s, and the base oil has a viscosity index of 100 to 120;
(b) a thickener represented by formula (A):

wherein R 2 is diphenylmethane; and R 1 and R 3 , which may be the same or different from each other, each represents cyclohexyl group or a straight-chain or branched alkyl group having 16 to 20 carbon atoms, with a molar ratio of the cyclohexyl group to the total number of moles of the cyclohexyl group and the alkyl group, expressed by [((the number of cyclohexyl groups)/(the number of cyclohexyl groups+the number of alkyl groups))×100] being 50 to 90 mol %;
(c) an amine type antioxidant; and
(d) an amine phosphate type antiwear agent.

2. The grease composition of claim 1 , wherein the amine phosphate type antiwear agent is a tertiary alkylamine-dimethyl phosphate, which is contained in an amount of 0.05 to 5 mass % based on the total mass of the grease composition.

3. The grease composition of claim 1 , further comprising a rust inhibitor comprising an organic sulfonate and an amine compound.

4. The grease composition of claim 3 , wherein the organic sulfonate is a calcium sulfonate, which is contained in an amount of 0.05 to 5 mass % based on the total mass of the grease composition.

5. The grease composition of claim 3 , wherein the amine compound is an amine salt of a fatty acid, which is contained in an amount of 0.05 to 5 mass % based on the total mass of the grease composition.

6. The grease composition of claim 1 , further comprising zinc dialkyldithiocarbamate, which is contained in an amount of 0.05 to 5 mass % based on the total mass of the grease composition.

7. A wheel bearing where the grease composition of claim 1 is enclosed.

8. The grease composition of claim 1 , wherein the content of the thickener is 3 to 20 mass % based on the total mass of the grease composition.

9. The grease composition of claim 1 , wherein the content of the amine type antioxidant is 0.05 to 5 mass % based on the total mass of the grease composition.

10. The grease composition of claim 1 , wherein the amine type antioxidant is phenyl a-naphthylamine, alkylphenyl a-naphthylamine, or alkyldiphenylamine.

Assignees

• Kyodo Yushi
• Ntn Toyo Bearing Co Ltd

Inventors

• Sato Yuta
• Tsutsui Daisuke
• Imai Junichi
• Hirano Shinsuke

Classifications

• C10N2050/10

  semi-solid; greasy · CPC title

• C10N2030/12

  Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives · CPC title

• C10N2030/10

  Inhibition of oxidation, e.g. anti-oxidants · CPC title

• C10N2030/06

  Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure · CPC title

• C10N2030/02

  Pour-point; Viscosity index · CPC title