Jtekt Corporation

Koyo Seiko Company, Ltd.

Seiji Nakahama

Shigeo Kamamoto

Junji Murata

Yuki Shishihara

Hiroki Matsuyama

Hiroshi Ueno

Keiichi Furukawa

Hiroyuki Chiba

A tapered roller bearing includes an inner ring, an outer ring, a plurality of tapered rollers, and an annular cage that holds the tapered rollers. The cage has a small annular portion positioned toward the axially first side with respect to the tapered rollers, a large annular portion positioned toward the axially second side with respect to the tapered rollers, and a plurality of cage bars that couples the small annular portion and the large annular portion together, and the cage is enabled to come into contact with an inner peripheral surface of the outer ring so that the contact allows the cage to be positioned in a radial direction. The small annular portion is provided with introduction channels through which lubricant is enabled to be introduced from a bearing exterior on the axially first side into an annular space formed between the inner and outer rings.

Tapered roller bearing

A tapered roller bearing includes an inner ring, an outer ring, a plurality of tapered rollers, and an annular cage. The cage has a small annular portion, a large annular portion, and a plurality of cage bars that couples the small annular portion and the large annular portion together. The cage is enabled to come into contact with an inner peripheral surface of the outer ring at least on an axially first side so that the contact allows the cage to be positioned in a radial direction. Each of the cage bars has pocket surfaces each of which faces an outer peripheral surface of the corresponding tapered roller, and each pocket surface has a flat surface shape that is straight in a direction from the inner ring toward the outer ring and that is enabled to come into line contact with the corresponding tapered roller.

A roller bearing assembly is provided which is adapted to enhance lubrication performance for preventing seizure and for reducing frictional torque during rotation. The roller bearing assembly includes an inner ring (), an outer ring () and a roller () rollably interposed between these inner and outer rings. The inner ring () is formed with a rib () making contact with a greater end face () of the roller () for guiding the rolling motion of the roller (). A recess () is formed centrally of the greater end face () of the roller (). A stopper member () for preventing oil invasion is fitted in the recess () of the roller ().

Oil-lubricated roller bearing assembly

The large-end-face roughness &sgr; of the tapered roller is set to be not less than 0.04 &mgr;mRa, consequently the assembling torque becomes generally constant and smaller in fluctuation over a range that the cone-back rib face roughness &sgr; is 0.03-0.23 &mgr;mRa. Also, the composite roughness &sgr;&equals;(&sgr; &plus;&sgr; ) is set to be not more than 0.17 &mgr;mRa, consequently the preload retention rate on the regression curve can be made 90%. Further, the radius of curvature ratio R1/R2 resulting from dividing the convex radius of curvature R1 of the large end face of the tapered roller by the concave radius of curvature R2 of the cone-back rib face of the inner ring is set to be not more than 0.35, consequently the rotating torque becomes smaller in variation and also smaller in fluctuations over a range that the composite roughness &sgr; is 0.05-0.22 &mgr;mRa.

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Osaka, Japan

Seiji Nakahama