| 摘要 |
<p>A bearing device for a wheel, wherein the bearing device has enhanced durability obtained by maintaining an appropriate preload in straight-ahead driving and by setting the bearing rigidity in turning to an appropriate level, the bearing device is flexibly adaptable to different product specifications, and the bearing device has reduced cost. A bearing device for a wheel, provided with an angular contact ball bearing having balls (6) arranged in double rows, wherein the inner rolling surface (3a) of an inner ring (3) is created by both a curvature radius (r) lying in the range from a position near a contact point (P) making contact with a ball (6) at an initial contact angle (a) up to the groove bottom of the inner rolling surface, and a curvature radius (r1) smaller than the curvature radius (r) and lying in the range from an inflexion point (P1) making contact with the ball (6) at a contact angle (a1) up to a large diameter section (3b) of the inner ring (3). The curvature radii (r, r1) relative to the diameter (d) of the balls are set so as to satisfy the relationships of 1.05d < 2r = 1.10d and 1.01d = 2r1 = 1.05d, and the inflexion point (P1) between the two curvature radii (r, r1) is set so that ?a is in the range from 2° to 8°, where a is in the range from 30° to 45° and a1 = a + ?a.</p> |
