| 摘要 |
PROBLEM TO BE SOLVED: To enable fixing a top cover to a fixing shaft without complicating constitution, and sealing the inside of a spindle motor by using a magnetic fluid seal having a small inner diameter. SOLUTION: An external thread part 34a, formed on one end portion of a fixing shaft 34, is inserted in an attaching hole 7a of a top cover 7 from the inside, a nut 37 is screwed on the external thread part 34a from the outside of the top cover 7, and the top cover 7 is fixed to the fixing shaft 34. A magnetic fluid seal 24 seals a part between a rotating part 9 and the one end portion of the fixing shaft 34, at the axial direction outside to a bearing 12 and at an adjacent position of the bearing 12. The magnetic fluid seal 24 is fixed to the rotating part 9, so as to face a small diameter part 34b which is formed in the adjacent part of the external thread part 34a of the fixing shaft 34, interposing a step-difference part 34c, in the diameter direction. |
