| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a spindle motor having a rotor portion stably rotated, and to provide a disk drive device. Ž<P>SOLUTION: A shielding member 27 of the spindle motor 1 has a third planar section 273 so formed that the axial height of its inner circumferential surface is uniform in the circumferential direction. The third planar section is positioned inside a first planar section 271 in the radial direction and inside a second planar section 272 adjoining to the first planar section 271 in the circumferential direction, in the radial direction. The axial height of the inner circumferential surface 273a of the shielding member 27 opposed to the outer circumferential surface 17a of a rotor magnet 17 with a gap is uniform in the circumferential direction. Therefore, magnetic bias is stabilized when the motor 1 is rotationally driven and this stabilizes rotation of the rotor portion 13 and suppresses the occurrence of trouble, such as PES (Positioning Error Signal). Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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