| 摘要 |
PROBLEM TO BE SOLVED: To realize a structure of low torque, hardly generating micro vibrations and reducing NRRO(non repeatable runout). SOLUTION: Circumference side recessed faces 14, 14 are formed at both end parts of each pocket, with respect to the circumferential direction of a main part 9. When a ball bearing is operated, the rolling surface of a ball 6 and the inner surface of each pocket 10a are brought into sliding contact at two points A, B. With two sliding contact points, the attitude of the ball 6 in each pocket 10a is stabilized to reduce micro vibrations and the NRRO. On the basis of the presence of the circumference side recessed faces 14, 14, such an oil film as to generate large shearing resistance is not formed between the inner surface and the rolling surface, so that torque can be lowered. |
