Motor and fan

摘要

A first seal portion having a surface of a lubricating oil defined therein is defined between a sleeve portion and a bearing housing. A side communicating channel arranged to bring a first seal gap and a thrust gap into communication with each other is defined either between a sleeve portion and a bearing housing or in an outer circumferential portion of a sleeve portion. A second seal portion having another surface of a lubricating oil defined therein is defined in a gap constituted by a side minute gap between a thrust plate and a bearing housing and a lower minute gap between a thrust plate and a cap member.

主权项

1. A motor comprising:
a stationary portion including a stator; and a rotating portion including a rotor magnet arranged opposite to the stator; wherein a bearing mechanism is arranged in the stationary portion and the rotating portion such that the rotating portion is rotatable with respect to the stationary portion; wherein the bearing mechanism includes:
a shaft;a sleeve portion arranged to have the shaft inserted therein;a thrust plate fixed to the shaft on a lower side of the sleeve portion, and including an outer circumferential surface having a diameter greater than that of a bottom portion of the sleeve portion;a bearing housing arranged to surround the sleeve portion and the thrust plate; anda cap member fixed to the bearing housing and being axially opposed to at least a lower side of an outer circumferential portion of the thrust plate; a radial dynamic pressure bearing portion arranged to support the shaft in a radial direction defined therein includes a radial gap defined between an inner circumferential surface of the sleeve portion and an outer circumferential surface of the shaft, while a thrust dynamic pressure bearing portion defined therein includes a thrust gap defined between a lower surface of the sleeve portion and an upper surface of the thrust plate; an outer circumferential surface of the sleeve portion and an inner circumferential surface of the bearing housing are arranged to together define a first seal gap therebetween, the first seal gap having a radial width gradually increasing with increasing distance from the thrust plate, the first seal gap including a first seal portion having a surface of a lubricating oil defined therein; a side communicating channel arranged to bring a bottom portion of the first seal gap and an outer edge portion of the thrust gap into communication with each other is defined on a lower side of the first seal portion and either between an outer circumferential portion of the sleeve portion and an inner circumferential portion of the bearing housing, or in the outer circumferential portion of the sleeve portion; and the outer circumferential surface of the thrust plate and the inner circumferential surface of the bearing housing are arranged to together define a side gap therebetween, and a lower surface of the outer circumferential portion of the thrust plate and an upper surface of an outer circumferential portion of the cap member are arranged to together define a lower gap therebetween, the side gap and the lower gap together constituting a second seal gap, the second seal gap including a second seal portion having another surface of the lubricating oil defined therein.