| 摘要 |
Disclosed is a spindle motor for hard disk drives capable of generating mechanical and electrical preloads to form a predetermined sized air gap through use of mechanical and electrical offsets, so that the spindle motor is prevented from being damaged by friction and heat generated during an initial starting. The spindle motor with mechanical and electrical offsets is designed so that a midpoint of the vertical width of the poles wound around by a coil of a stator is placed within a magnetic field so as not to be flush with a midpoint of the vertical width of a permanent magnet fitted on the inner circumferential surface of the hub, and each of the poles has at least one of its upper and lower end extending in a vertical direction by a predetermined length to distribute magnetic flux density differently between the upper and lower ends of each pole.
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