DYNAMIC PRESSURE BEARING APPARATUS AND FAN

摘要

A dynamic pressure bearing apparatus includes a bearing portion, a shaft, a radial dynamic pressure bearing portion, and a seal gap. An annular member arranged in an annular shape, fixed to the shaft axially between the seal portion and the attachment surface, and arranged to extend radially outward beyond an opening of the seal gap. A minute horizontal gap extending radially is defined between an upper surface of the bearing portion and a lower surface of the annular member. The seal gap is arranged to be in communication with an exterior space through the horizontal gap.

主权项

1. A dynamic pressure bearing apparatus comprising:
a bearing portion; a shaft inserted in the bearing portion, and arranged to rotate about a central axis relative to the bearing portion, an outer circumferential surface of the shaft including an attachment surface to which an impeller is to be attached directly or through one or more members; a radial dynamic pressure bearing portion defined by an inner circumferential surface of the bearing portion, the outer circumferential surface of the shaft, and a portion of a lubricating oil which exists in a radial gap defined between the inner circumferential surface of the bearing portion and the outer circumferential surface of the shaft, and arranged to generate a fluid dynamic pressure in the portion of the lubricating oil; a seal gap defined by the inner circumferential surface of the bearing portion and the outer circumferential surface of the shaft on an upper side of the radial dynamic pressure bearing portion, the seal gap including a seal portion having a surface of the lubricating oil defined therein; and an annular member arranged in an annular shape, fixed to the shaft axially between the seal portion and the attachment surface, and arranged to extend radially outward beyond an opening of the seal gap; wherein a minute horizontal gap extending radially is defined between an upper surface of the bearing portion and a lower surface of the annular member; and the seal gap is arranged to be in communication with an exterior space through the horizontal gap.