| 摘要 |
PROBLEM TO BE SOLVED: To provide a disk drive motor in which pitching natural vibration frequency can be increased without increasing the external size of a motor and shock resistance and durability of a ball bearing can be improved. SOLUTION: In a disk drive motor 1, an outside diameter size D1 of a first and a second ball bearings 4, 5 is nearly equal to an outside diameter size D2 of a clamper guide part 241 of a hub 2. The first and second bearings 4, 5 having the large outside diameter size D1 are used, so that the diameter of a rotary shaft 8 is large as compared with the conventional case. By the corresponding amount, the pitching natural vibration frequency is increased. As a result, a bearing span can be made slightly shorter, so that the thickness dimension of the hub 2 can be ensured. Since the outer diameter size D1 of the first and second ball bearings 4, 5 is made large, load capacities of the ball bearings 4, 5 are increased, and shock resistance and durability can be improved.
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