Nsk Corporation

Nippon Seiko Kabushiki Kaisha

Shinichi Shirota

Yasuo Murakami

Shigeru Okita

Kyozaburo Furumura

Nobuaki Mitamura

Takeo Ohkuma

Kazuo Sekino

Akihiko Tanaka

An object of this invention is to provide a rolling bearing in which, as for the rolling elements, it is unnecessary to employ a high level heat treatment such as carburizing or carbonitriding which requires a long period of time to achieve, and which is sufficiently long in service life even when used with a lubricant containing foreign matters. In a rolling bearing, the amount of residual austenite (.gamma..sub.R vol %) in the surface layer of at least one of the inner and outer races is in a range of 25 to 40 vol %, and the surface hardness (Hv) thereof meets the following condition:

Rolling bearing

A ball-and-roller bearing provided with a bearing ring and rolling element has the surface hardness of at least one of the bearing ring and rolling element of Hv 900 or more and the minimal compression residual stress of 100 kgf/mm.sup.2 or more in the depth from the surface of the bearing ring and/or rolling element to the depth equivalent to a 2% of the mean diameter of the rolling element and at the same time, the bearing is closely sealed to prevent any foreign particles from being ingressed thereinto, thus making possible a significant improvement of its longevity.

Ball-and-roller bearing

A rolling bearing having bearing rings and rolling members wherein at least one of the bearing rings and the rolling members essentially consists of an alloy steel which contains carbide-forming elements. The bearing rings and the rolling members are subjected to carburizing or carbo-nitriding and then hardening to form a rolling surface layer. The content of retained austenite (.gamma..sub.R vol %) in the rolling surface layer is from 20 to 45% by volume and the hardness (Hv) of the rolling surface layer reinforced by dispersion of fine carbides or carbonitrides with an average grain size of from 0.5 to 1.5 .mu.m with regard to the content of the retained austenite (.gamma..sub.R vol %) is within the range of:

Bearing apparatus for gear type power transmission systems comprising a gear casing containing a lubricating oil, gearing for power transmission retained in the casing and a bearing carried in the casing for rotatably supporting the gear shaft employs a seal for the bearing containing a lubricant so that the bearing is lubricated separately and independently of the oil in the casing.

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Ebina, Japan

Shinichi Shirota