| 摘要 |
PURPOSE:To prevent reverse rotation from occurring by forming a hub part in double structure, and providing a gear locked only in a direction desired to rotate and a lock mechanism operated by a centrifugal force between an outside hub and an inside hub. CONSTITUTION:The gear 7 locked only in the direction desired to rotate and is not locked when a motor is rotated in a reverse direction is provided between the outside hub 1 and the inside hub 2. Also, the lock mechanism 8 is provided which locks the outside hub 1 and the inside hub 2 when the centrifugal force generated by increasing rotating speed exceeds a prescribed level and unlocks them when it goes less than the prescribed level. When a current is permitted to flow on a stator 10 and excitation is performed sequentially, a spindle motor is rotated only in a target direction. Thereby, only the inside hub 2 is rotated and no outside hub 1 is rotated even when the exciting sequence of the stator 10 is set at the reverse direction, which prevents the reverse rotation from occurring. |
