Fluid dynamic bearing unit

摘要

A fluid dynamic bearing unit includes a bearing housing ( 20 ) axially defining therein a bearing hole ( 21 ), a rotary shaft rotatably received in the bearing hole with a radial space formed between the rotary shaft and the bearing housing, and lubricant filled in the radial space. A ventilating path ( 25 ) is formed in a wall of the bearing housing to communicate a bottom of the bearing hole with an exterior of the bearing housing.