| 摘要 |
<p>A rolling bearing unit with a rotation speed detection instrument comprises; a hub rotating together with a wheel at the time of its use, the hub having a plurality of inner race tracks in an outer peripheral surface thereof; an outer race formed of steel material, which is supported by a suspension device and does not rotate at the time of its use, the outer race having a plurality of outer race tracks in an inner peripheral surface which face the inner race tracks; rolling elements, each being rotatably provided between the inner race track and the corresponding outer race track; an encoder fixedly provided at a portion of the outer peripheral surface of the hub between the inner race tracks; the encoder exhibiting a characteristic which changes in its circumference direction alternately at equal intervals; and a sensor having a detecting section, the sensor being supported in a mounting hole provided in an intermediate portion of the outer race in its axial direction so that the detecting section may face the encoder and changing its output signal in response to the change of the characteristic of the encoder. <??>The hardened layer is formed in the inner surface of the outer race, and each portion where the outer race track is formed, and a distance between an end periphery of the outer race track which is closer to said mounting hole and the mounting hole is 10.5 mm or less, and a portion where said mounting hole is formed is not hardened and a thickness of the hardened layer formed in the outer race track closest to said mounting hole is 1.5 mm or more. <IMAGE></p> |
