Hydro dynamic gas bearing and disk drive using the same

摘要

The invention has an object to prevent discharge of foreign matters into an inner space of a casing and to improve movement stability and reliability of the disk drive. A sleeve with one end closed is connected to a front end of a shaft supported at its proximal to a base on a fixed side, a plurality of hydro dynamic pressure generating grooves are formed on at least one of an outer peripheral surface of the shaft and an inner peripheral surface of the sleeve opposite the outer peripheral surface, a through hole communicating with the outside of the base is formed to extend from the front end to the proximal end of the shaft, and the through hole is provided with an air vent for adjusting a pressure between the shaft and the sleeve so that the amount of air to be discharged to the outside is adjusted and the sleeve is rotated in a contactless fashion with the shaft. Foreign matters are carried in a gas passing through the air vent and guided to the outside through the through hole.