| 摘要 |
A spindle motor includes a shaft (2) secured on a base (1) to extend vertically therefrom, and a rotor hub (8) journalled rotatably around the shaft (2) through a plurality of anti-friction bearings (3,4) each of which has outer (3b, 4b) and inner (3a, 4a) races and rotational bodies disposed between the races. A cylindrical sleeve (5) having a through bore is disposed between an outer peripheral surface of each anti-friction bearing (3,4) and an inner peripheral surface of a central bore provided through the rotor hub (8). The sleeve (5) and the outer races (3b, 4b) of the anti-friction bearings (3, 4) are made of ferrous metal material of substantially the same coefficient of expansion, and the inner races (3a, 4a) of anti-friction bearings (3, 4) and the shaft (2) are also made of ferrous metal material of substantially the same coefficient of expansion. <IMAGE> |
