Koyo Seiko Company, Ltd.

Hajime Tazumi

Yoshitaka Nakagawa

Junya Ooitsu

Hideki Fujiwara

Tsuyoshi Okumura

Yasuhito Tanaka

Tadahiro Terada

Masayuki Kitamura

Hiroshi Ueno

Masao Goto

Yoshiki Fujita

Hisashi Harada

Shigetaka Ashida

Hiroyuki Miyazaki

Kazuyuki Nishikita

Hideji Yoshida

Toshiharu Watanabe

A rolling bearing including a rolling element made of steel is provided. The rolling element has a hardness of 620 to 750 HV in its interior. The rolling element is so constructed that the hardest point may exist within a depth of 10% of its diameter from a rolling contact surface of the rolling element, and that the hardness at this point is made higher by 20 to 150 HV than the hardness in the interior.

Rolling bearing

A method of manufacturing a steel ball for a rolling bearing, said method comprising: a molding step of forming a steel wire cut at a predetermined length into a raw ball having a band portion by a pair of molding forms having respectively hemispherical concave portions and relief grooves in peripheries of said concave portions on their respective opposing faces, said band portion being formed on a surface of said raw ball along said relief grooves by compressing said steel wire by said molding forms in a state in which both ends of said steel wire are sandwiched between said concave portions; and a tumbler working step of removing said band portion from the surface of the raw ball by tumbling.

Manufacturing method of steel ball for rolling bearing

A rolling bearing such as a rolling bearing for an alternator of an automobile, the life period of which is prevented from being shortened due to the temporal reduction of a radial internal clearance even in a high temperature environment. The rolling bearing includes a plurality of rolling elements rotatably arranged between an inner race and an outer race, and at least the inner race and the outer race are made of a steel material. An austenite residual rate of the inner race is smaller than an austenite residual rate of the outer race. The amount of dimensional expansion of the outer race due to the martensite transformation of residual austenite is larger than that of the inner race, so that the occurrence of clearance loss is suppressed even when dimensional expansion of the rolling elements occurs.

A structure of at least a stationary-side race of a bearing is transformed into a lower bainite structure through an isothermal transformation treatment. Furthermore, the adjustment is made for hardness to HRC&equals;54 to 64, an amount of residual austenite to not more than 5% and an area percentage of 0.8 &mgr;m or longer carbide to not more than 20% based on the total area of secondary carbide. Thus is prevented the occurrence of a white layer in the rolling bearing.

A one-way clutch for switching a power transmitting state and a power transmission interrupting state between an inner ring member and an outer ring member. At a plurality of circumferential portions of one of the inner ring member and the outer ring member, there are formed cam faces between the circumference of the one of the inner and outer ring members for forming wedge-shaped spaces which are narrowed in one circumferential direction. These cam faces are made to have a higher hardness than that of rollers which are individually arranged in the wedge-shaped spaces. As a result, the cam faces are suppressed from wear as the time elapses, and the wedge angle of the wedge-shaped spaces is kept substantially constant.

One-way clutch

A one-way clutch has an annular space through which an outer ring and an inner ring face each other, the outer ring and the inner ring being disposed inside and outside each other in a diameter direction and concentrically with each other. A lubricant for lubricating an inner peripheral face of the outer ring and an outer peripheral face of the inner ring on which rollers roll is prepared by mixing a urea-based consistency increasing agent into ester-based or synthetic oil-based base oil with a pressure viscosity coefficient (at a temperature of 25&deg; C.) set at 12 GPa or more. The lubricant provides for movement of state switching components to be stabilized even at a low temperature and wear of the state switching components and operating faces can be suppressed even at a high temperature.

A one-way clutch has rollers individually disposed in wedge-shaped spaces formed at positions along a circumference between an inner annular body and an outer annular body which are disposed concentrically. The wedge angle of each wedge-shaped space is fixed at a preferred value. As a result, an engagement position of the roller becomes shallow when the roller is positioned on a narrower side of the wedge-shaped space and gaps between the roller and the inner and outer annular bodies become small when the roller is positioned on a wider side of the wedge-shaped space. Therefore, the rollers move smoothly when switching between the lock state and the free state.

A one-way clutch for switching between a locking state in which an inner wheel and an outer wheel rotate synchronously, and a free state in which they rotate relative to each other. The one-way clutch includes a holding device having pockets for accommodating rollers provided at several positions on its circumference, and coil springs which are accommodated in each of the pockets in a compressed state for urging the rollers to a locking side of a pocket. The coil springs are in contact at points which span over 1/2 the width of the roller in the axial direction of the roller. As a result, a balanced urging force of the coil spring can be supplied to the roller, so that the rollers rotate smoothly and with a proper posture. Deflection of the coil springs is inhibited by alignment portions included at a surface of each pocket.

One-way clutch and auxiliary machine using the same

In an annular space between a pulley and a shaft body disposed coaxially with each other, a one-way clutch is interposed in an intermediate range in an axial direction and rolling bearings are disposed on both sides in the axial direction of the one-way clutch. A tightening distance for fitting between the one-way clutch and pulley is set to be smaller than that between the rolling bearing and pulley. Due to this structure, in a condition in which an excessive radial load acts upon the pulley, that radial load acts on not the one-way clutch but the rolling bearings on both sides thereof, so that a clutch operation of the one-way clutch can be carried out stably.

Pulley unit

A pulley unit comprising two inner and outer annular bodies disposed coaxially and a one-way clutch interposed in an annular space between both the annular bodies, both ends in the axial direction of the annular space being sealed by a seal and at least the sealed portion of at least one seal being hidden by an annular member mounted to the inner annular body. By this structure, the sealed portion by the seal is protected from a direct splash of water, so that invasion of water through the sealed portion becomes unlikely to occur.

A ball bearing cage is formed with pockets each having an inwardly curved spherical pocket face similar to a ball in shape. At least one of the pockets has a protrusion projecting inwardly thereof from one of inner and outer circumferential edge portions of the pocket face. A ball bearing comprises balls retained between inner and outer bearing rings and equispaced circumferentially thereof by a cage. The cage is formed with pockets each having an inwardly curved spherical pocket face similar to the ball in shape, at least one of the pockets having a protrusion projecting inwardly thereof from an edge portion of the face close to the fixed one of the rings.

Growing community of inventors

Osaka, Japan

Hajime Tazumi