Koyo Seiko Company, Ltd.

Jtekt Corporation

Nippon Koshuha Steel Co., Ltd.

Masamichi Shibata

Kenji Shitsukawa

Nobuo Komeyama

Hisashi Harada

Kenji Asano

Yoshiaki Hyodo

Masaaki Sakuragi

Toshihiro Miyakawa

Yasuaki Nagai

At least a race () of a blank (B) for forming a bearing raceway member is hardened by heating and is finished to predetermined precisions. Subsequently, the race () is roller burnished for additional hardening. The blank (B) is formed from a steel for bearing manufacture and is subjected to the roller burnishing, thereby achieving a hardness of HRC65 or more at a surface of the race (), and a center-line average roughness Ra of 0.1 &#x3bc;m or less at the surface of the race () and achieving a hardness of HRC60 or more at the depth of at least 0.2 mm from the surface of ().

Method for manufacturing a bearing raceway member

A bearing is provided which can be sufficiently processed by a usual NC grinding machine, and attain a life period that is substantially equal to that of a bearing having a theoretical crowning shape which is derived from the elastic contact theory, even when the bearing is used in a portion to which a heavy load or a high torque load is applied. As means for realizing such a bearing, a generating line of a rolling surface of a roller or a raceway surface of an inner or outer race is divided into a plurality of zones, and the shape of the generating line is approximated to a special curve shape which is theoretically derived, by a plurality of circular arcs which are contacted with each other on the border line between the corresponding zones. Therefore, it is possible to obtain a roller bearing which can be practically used, and which can attain a life period that is substantially equal to that of a bearing having an ideal crowning shape.

Roller bearing and a method of producing the same

There is provided a roller bearing in which contact stress between a roller and a raceway is uniformized by optimizing a configuration of a clearance between the roller and the raceway. A configuration of an outer circumferential surface (,) of a tapered roller (,) of a tapered roller bearing (,) is defined so that a clearance of Y(x)&equals;kYp(x), which results from multiplying an equation Yp(x) for uniformizing contact stress between infinite-width plate and tapered roller by a positive number k&equals;1.5-10, is formed between the raceway surface (,) and the outer circumferential surface (,) of the tapered roller (,). The tapered roller (,) relaxes concentration of contact stresses, improving the durability.

Roller bearing

a high carbon chromium bearing steel having a carbon content from 0.8% to 1.2% by weight, and which is characterized by a nickel content of 1.0% to 2.0% by weight, a chromium content of 0.9% to 2.0% by weight, a silicon content of 1.0% to 2.0% by weight, and a sulfur combined and phosphorus content of 0.015% to 0.040% by weight.

High carbon chromium bearing steel

Growing community of inventors

Mie, Japan

Masamichi Shibata