| 摘要 |
PURPOSE:To improve wow and flutter by using a ball bearing with a shaft groove, where a capstan shaft is directly provided with a groove for balls of said ball bearing to roll therein, as a bearing for journaling said capstan shaft. CONSTITUTION:A bearing holder 2 is equipped with a ball bearing 7 with a shaft groove on the output end side and with a ball bearing 8 with an inner ring on the side opposite to the output end side, to journal a capstan shaft 1 by the both bearings 7, 8. Also, a pre-load is applied to the ball bearing 7 with a shaft groove on the output end side in the thrust direction by a pre-load spring 9, and a pre-load is applied to the ball bearing 8 with an inner ring on the side opposite to the output end side in the thrust direction by the attracting force of a driving magnet 5 and a stator yoke 3. That is, factors of the radial run-out of the inner ring and axial runout by a space between the inner ring and capstan shaft 1 are eliminated, because the capstan shaft 1 directly plays the role of the inner ring of the ball bearing 8 with an inner ring in the ball bearing 7 part with a shaft groove. Thus, it is possible to reduce the axial runout and to improve wow and flutter. |
