Ntn Corporation

Kyodo Yushi Co., Ltd.

Motohiro Ito

Takayuki Kawamura

Hidenobu Mikami

Yoji Sato

Yasushi Shibata

Ryouta Kondou

Takashi Azuma

Yoshihisa Imamoto

Provided is a grease composition which can be used as a lubricant for roller bearings, exhibits excellent high temperature durability and rust preventive property, and can prevent premature flaking on the rolling surface due to hydrogen embrittlement. A roller bearingis obtained by sealing a grease compositionin the periphery of a rolling element, this grease compositionis composed of a base oil excluding an ester-based synthetic oil, a thickener, and an additive, the additive contains (a) an alkanolamine and (b) 2,2,4-trimethyl-1,2-dihydroquinoline or a polymer thereof but does not contain an organic sulfonate, and (a) and (b) are contained at from 0.1 to 10 parts by weight with respect to 100 parts by weight of a total amount of the base oil and the thickener, respectively.

Grease composition and grease-sealed roller bearing

A rolling bearing that can prevent peeling on a surface of an iron-based metal member by hydrogen brittleness even under a severe environment is provided. The rolling bearinghas plural bearing elements formed of an iron-based metal, and a lubricant compositionthat lubricates metal contact surfaces of the respective bearing elements, the lubricant compositionis a grease containing a base oil and alkanolamine and being free of alkali metal salts and alkaline earth metal salts of inorganic acids, the base oil is at least one oil selected from alkyl diphenyl ether oils, poly-&#x3b1;-olefin oils and ester oils, and the alkanolamine is contained by 0.1 to 10 parts by weight with respect to 100 parts by weight of the total amount of the base oil and a thickener.

Rolling bearing

The present invention provides a grease composition having an excellent fretting wear resistance in a wide temperature region from low to high temperatures and particularly even at low temperatures and a rolling bearing in which the grease composition is packed. A grease composition () is packed inside a grease-packed bearing (). The grease composition () contains base oil, a thickener, and an additive. The additive contains at least, one kind selected from among a phosphite ester of formula (1) or a phosphite ester of formula (2): 

Grease composition and rolling bearing

The invention provides a grease composition for hub unit bearing, containing (a) an aromatic diurea thickener, (b) a base oil, (c) a metal salt of oxidized wax, (d) diphenyl hydrogen phosphate, and (e) at least one rust preventive selected from the group consisting of sulfonate rust preventives and carboxylic acid rust preventives. The grease composition of the invention shows excellent anti-fretting properties at low temperature, and at the same time, exhibit excellent rust preventing properties.

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Mie, Japan

Motohiro Ito