| 摘要 |
PURPOSE: To provide more miniaturization and stable rotational performance. CONSTITUTION: A hollow rotary unit 8 is externally fitted turnably relating to a fixed shaft 11. Dynamic pressure generating grooves 12a, 12b are provided vertically symmetrically in the fixed shaft 11. A radial air bearing, by a dynamic pressure from the dynamic pressure generating grooves 12a, 12b, supports the rotary unit 8 in a vertical direction relating to the fixed shaft 11. A thrust magnetic bearing 3 supports the rotary unit 8 in a parallel direction relating to the fixed shaft 11. For supporting the rotary unit 8 by the radial air bearing, in a range where the dynamic pressure generated in a vertical direction relating to the fixed shaft 11 is sufficiently large further almost uniform, a center point (c) of supporting the rotary unit 8 by the thrust magnetic bearing 3 is arranged. Consequently, sufficient miniaturization is accomplished, to prevent conical vibration, also capable of obtaining stable rotation. |
