| 摘要 |
PROBLEM TO BE SOLVED: To reduce running out at a rotor by inserting a damping means, in a region where deforming energy excited by ball bearings is most concentrated. SOLUTION: The base plate 10 of this spindle motor has a support housing 11 projecting and having an inside diameter larger than the peripheral surface of its shaft 20, and a ball bearing unit 50 composed of an upper bearing 51 and a lower bearing 52 is provided between the peripheral surface of the shaft 20 and the internal peripheral surface of the support housing 11. The upper bearing 51 and the lower bearing 52 are separated at a specified interval. A damping means 70 is formed so as to be inserted into the space between the outer rings 51b, 52b of the upper and lower bearings 51, 52 opposed to each other, and to adhere closely to the outer rings 51b, 52b. Consequently, it is possible to absorb vibration generated between the bearings smoothly, and to reduce running out at the rotor sharply.
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