| 摘要 |
PROBLEM TO BE SOLVED: To obtain an easily produceable constitution for a spindle motor, having radial and thrust dynamic pressure bearings by maintaining the surface of the thrust dynamic pressure bearing at satisfactory perpendicularity with respect to the rotating shaft of the motor. SOLUTION: A hollow cylindrical ring 4 is fixed integrally to the outer periphery of a shaft 2. A dynamic groove is provided on one of the upper and lower surfaces of the ring 4 facing each other, so that the outer peripheral surface of the ring 4 functions as a radial dynamic pressure bearing, and the upper and lower surfaces of the ring 4 function as a thrust dynamic pressure bearing. By forming the ring 4 accurately, the surface of the thrust dynamic pressure bearing of a rotor section 16 can be constituted at satisfactory perpendicularity with respect to the rotating shaft of the spindle motor. Since the need for the work for press-fitting and fixing two members to each other with high accuracy that has been required in prior art is dispensed with, the workability of the producing work and quality of this spindle motor are improved, and the manufacturing cost of the motor can be reduced.
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