Patent ID: 9183876
Filing Date: 2015-11-10
Classification: G11B,H02K

Abstract:
1. A spindle motor comprising: a sleeve including a bearing hole; a holding portion including a hole or a recessed portion configured to accommodate a portion of the sleeve; a stator located radially outside of the holding portion, and including a plurality of coils; and a rotor hub configured to rotate about a central axis extending in a vertical direction; wherein the rotor hub includes a circular first horizontal surface, a cylindrical surface, and an annular second horizontal surface; the first horizontal surface is located above the sleeve; the cylindrical surface extends downward from the first horizontal surface; the second horizontal surface is located above the stator; the rotor hub further includes a projecting portion that projects downward from the second horizontal surface, and surrounds the sleeve or the holding portion; the cylindrical surface and an outer circumferential surface of the sleeve are configured to together define a tapered gap therebetween where a radial distance between the cylindrical surface and the outer circumferential surface of the sleeve decreases with increasing height; the tapered gap includes a liquid surface of a lubricating fluid defined therein; the holding portion, the projecting portion, and the coils are radially arranged in order; at least portions of the holding portion, the projecting portion, and the coils are positioned to radially overlap with one another; an outer circumferential surface of the holding portion is located radially opposite to an inner circumferential surface of the projecting portion with a minute gap intervening therebetween; the minute gap has a radial width smaller than the radial distance between the cylindrical surface and the outer circumferential surface of the sleeve; and the minute gap is located below the tapered gap.