Koyo Seiko Company, Ltd.

Kenji Shitsukawa

Masamichi Shibata

Kenji Asano

Yasuaki Nagai

Masaaki Sakuragi

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.

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Minami Kawachi-gun, Japan

Kenji Shitsukawa