Patent ID: 8665558
Filing Date: 2014-03-04
Classification: G11B,H02K,Y10T

Abstract:
1. A disk drive device comprising: a base member; a hub on which a recording disk is to be placed; a bearing unit arranged on the base member for rotatably supporting the hub; and a spindle drive unit for rotationally driving the hub, the spindle drive unit comprising: the hub comprising an outer cylindrical portion to be engaged with an inner periphery of the recording disk, and an inner cylindrical portion upholding the magnet, the bearing unit being encircled by the recording disk in a radial direction, and including a portion at least partially overlapping the recording disk in an axial direction, the number of magnetic poles being an even number in a range of 10 to 16, and the number of salient poles being a multiple of 3 in a range of 12 to 24.