| 摘要 |
PROBLEM TO BE SOLVED: To improve the strength of a casing without providing a complicated mechanism by fixing the lower end of a fixed shaft which turnably supports a hollow rotary shaft of a. spindle motor to the upper surface of a movable tray part and supporting the rear surface of an upper surface case from the lower side with the upper end. SOLUTION: A fixed shaft 24 is set up at the central part of a hollow rotary shaft 25 having a hollow structure, and its lower end is fixed to a movable tray part 22. The fixed shaft 24 is arranged in the hollow part of the center of the hollow rotary shaft 25, and the upper end of the fixed shaft 24 is provided with a hemispheric shape part 28. An upper surface case 20 is brought into contact with the hemispheric shape part 28 at the upper tip end of the fixed shaft 24, or is arranged in a position across a slight distance. Thus, since the upper surface case 20 is supported from the lower side with the fixed shaft 24 and the hemispheric part 28 against a deflection in the downward direction of the upper surface case 20 owing to a warp or distortion of a bottom surface case 21 and the upper surface case 20, the upper surface case 20 is prevented to come into contact with the hollow rotary shaft 25 of a spindle motor 23.
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