Grease for rolling bearing

Patent metadata

Field	Value
Publication number	US-9732798-B2
Application number	US-201615002046-A
Country	US
Kind code	B2
Filing date	Jan 20, 2016
Priority date	Jan 21, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A grease composition includes a base oil, a thickener and at least one kind of an antioxidant selected from an amine-based antioxidant and a phenol-based antioxidant expressed by the following respective general formulas (1) and 2:

The base oil contains a poly-α-olefin and a mineral oil. A mass ratio of poly-α-olefin/mineral oil is 1.25 to 9.

First claim

What is claimed is:

1. A grease for a rolling bearing, comprising:
a base oil containing a poly-α-olefin and a mineral oil, a mass ratio of poly-α-olefin/mineral oil being 1.25 to 9;
a thickener; and
at least one kind of an antioxidant selected from an amine-based antioxidant (A) expressed by the following general formula (1), and a phenol-based antioxidant (B) expressed by the following general formula (2);

wherein in formula (1), R 1 and R 2 each independently represents an alkyl group having 1 to 12 carbon atoms, or a hydrogen atom, provided that, at least one of R 1 and R 2 is an alkyl group having 1 to 12 carbon atoms,

wherein in formula (2), R 11 and R 12 each independently represents an alkyl group having 1 to 8 carbon atoms, R 13 represents an alkylene group having 1 to 8 carbon atoms, n represents a number of 1 to 6, X 1 represents a residue obtained after n hydroxyl groups are removed from an aliphatic m-hydric alcohol having 1 to 24 carbon atoms, and m in the aliphatic m-hydric alcohol represents a number of 1 to 6, provided that, when n is 5 or 6, the number of carbon atoms of the aliphatic m-hydric alcohol in X 1 is 2 to 24; wherein the mineral oil is a refined mineral oil that is classified as Group III in a base oil category defined by the American Petroleum Institute, and the flash point of the refined mineral oil is 240° C. or higher; and
wherein a kinematic viscosity v 1 of the mineral oil at 40° C. is higher than a kinematic viscosity v 2 of the poly-α-olefin 40° C.

2. The grease for a rolling bearing according to claim 1 , wherein the grease contains both the amine-based antioxidant (A) and the phenol-based antioxidant (B).

3. The grease for a rolling bearing according to claim 2 , wherein the amount of the amine-based antioxidant (A) is greater than the amount of the phenol-based antioxidant (B) on a mass basis.

4. The grease for a rolling bearing according to claim 1 , wherein the base oil contains a refined mineral oil that is classified as Group III in a base oil category defined by the American Petroleum Institute, and the flash point of the refined mineral oil is 250° C. or higher.

5. The grease for a rolling bearing according to claim 1 , wherein the poly-α-olefin is a mixture of trimers to pentamers of α-olefin having 8 to 12 carbon atoms.

Assignees

• Seiko Instr Inc

Inventors

• Iino Akihiro
• Nakayama Yukihiro
• Hanaoka Misato
• Nakamura Hisaya
• Yoda Hiroki

Classifications

• C10N2040/02

  Bearings · CPC title

• C10N2030/12

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

• F16C19/54

  Systems consisting of a plurality of bearings with rolling friction (spindle bearings F16C35/08) · CPC title

• C10N2030/10

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

• C10N2040/18

  in connection with recordings on magnetic tape or disc · CPC title