Patent ID: 8630063
Filing Date: 2014-01-14
Classification: F16C,G11B,H02K

Abstract:
1. A bearing mechanism comprising: a shaft portion centered on a central axis extending in a vertical direction, and including a cylindrical outer circumferential surface; a sleeve portion including a sleeve body and a lower thrust plate, and arranged to be rotatable about the central axis, the sleeve body including a through hole in which the shaft portion is accommodated, and the lower thrust plate being fixed to a lower portion of the sleeve body; a lower opposing portion arranged to extend radially outward from a lower portion of the shaft portion, and including an upper surface arranged axially opposite a lower end surface of the sleeve portion with a lower thrust gap defined therebetween; a lower outer annular portion whose position relative to the lower opposing portion is fixed, and including a cylindrical or substantially cylindrical inner circumferential surface arranged to surround at least a portion of an outer circumferential surface of the sleeve portion; and an upper opposing portion arranged to extend radially above the sleeve portion, and including a lower surface arranged axially opposite an upper end surface of the sleeve portion with an upper thrust gap defined therebetween; wherein the outer circumferential surface of the shaft portion and an inner circumferential surface of the sleeve portion are arranged to together define a radial gap therebetween, the radial gap including a radial dynamic pressure bearing portion defined therein; the lower thrust gap includes a lower thrust dynamic pressure bearing portion defined therein; the outer circumferential surface of the sleeve portion and the inner circumferential surface of the lower outer annular portion are arranged to together define a lower seal gap therebetween, the lower seal gap including a lower seal portion defined therein; an upper seal gap is defined continuously with the upper thrust gap, the upper seal gap including an upper seal portion defined therein; the sleeve body includes a lower annular surface arranged to extend radially around the central axis, and arranged opposite to an upper surface of the lower thrust plate; the sleeve portion includes: the lower mouth portion is arranged to axially overlap with the lower thrust dynamic pressure bearing portion; a circulation channel including the lower thrust gap, the radial gap, the upper thrust gap, the first communicating channel, and the second communicating channel is arranged to be in communication with both the lower seal gap and the upper seal gap; and the circulation channel, the lower seal gap, and the upper seal gap are filled with a lubricating oil.