| 摘要 |
PROBLEM TO BE SOLVED: To obtain a spindle motor capable of correcting the balance with high accuracy by stabilizing the rotational orbit of spheres. SOLUTION: In the spindle motor 1 furnished with a shaft 5b, a rotor case 5c and a turntable 6, the turntable 6 is provided with a peripheral wall 6f sunk down to the side of a rotor case 5c to form the annular space S to the inside, and the inner peripheral surface of the peripheral wall 6f is constituted of plural peripheral surfaces with different angles, and in the annular space S, a ring magnet 12 is fixed and also the plural spheres 11 consisting of magnetic materials are arranged so as freely rollable at the side outer than the ring magnet 12, then the spheres 11 are attracted to the outer periphery of the ring magnet 12 at the time of stopped state of the turntable 6 or at the time of low speed rotation and rotated while keeping the rotational balance of the disk by bringing into point contact with each of the plural peripheral surfaces at the time of high speed rotation of the turntable 6.
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