Patent ID: 7667360
Filing Date: 2010-02-23
Classification: F16C,G11B,H02K

Abstract:
1. A bearing mechanism for a motor, comprising: a rotor unit including a bushing and a shaft fixedly attached to the bushing, the bushing having an inner circumferential surface defining an axially extending through hole centered about a center axis, an axial upper portion of the shaft being interference-fitted in the through hole, and the inner circumferential surface of the bushing includes a concave portion extending along a circumferential direction of the bushing; a sleeve having a substantially cylindrical shape and a closed axial lower end, an axial lower portion of the shaft being inserted into the lower end of the sleeve, and an axial upper portion of the sleeve axially facing the bushing radially outside of the shaft with a gap defined therebetween; lubricating oil filled in the gap defined between the axially upper portion of the sleeve and the bushing; and a rotor hub arranged to support a rotor magnet; wherein the rotor hub includes an inner lower edge fixedly attached to a top portion of a radially extending protrusion of the bushing; the bushing is made of a first material, the rotor hub is made of a second material, and the first material is more rigid than the second material; substantially no portion of the bushing axially overlaps with any axially uppermost surface of the rotor hub; and the rotor hub, the bushing, and the shaft all rotate together.