| 摘要 |
PROBLEM TO BE SOLVED: To provide a hard disk driving device which has a good rotating property by a user using a bearing device into which fellow parts are already assembled, as it is, for a motor. SOLUTION: An inner peripheral rolling groove 2a is formed on the outer periphery of a large diameter part of a two-step shaft 1 having the large diameter part 1a and the small diameter part 1b, and balls 4 are filled between the inner peripheral rolling groove 2a, and the outer peripheral rolling groove 2b formed on the inner peripheral surface of the outer ring 3 at the large diameter side. To a bearing device composed by fitting the inner ring 5a of a ball bearing to the small diameter part 1b of the two-step shaft while holding a tubular spacer 7 at whose both ends the small diameter parts fitted to the inner sides of the outer ring of the large diameter part and the outer ring of the ball bearing are formed respectively, between the outer ring 5b of the ball bearing 5 filling the balls 6 between the inner ring 5a and the outer ring 5b, and the outer ring 3 at the large diameter side, the center hub of a rotor in a motor is fitted and fixed.
|
