A magnet (13) for trapping abraded powder is disposed in a connecting
passage between an opening of a sleeve and an opening of a hydrodynamic
bearing motor, and a shaft (3), a sleeve (4), a thrust flange (7), and a
thrust main plate (5) are made of an austenitic stainless. With this
configuration, since the austenitic stainless acting as a nonmagnetic
substance is used, it is possible to increase a degree of cleaning.
Further, abraded powder of the austenitic stainless is transformed into a
magnetic substance, and thus a flow of the abraded powder to the outside
can be prevented by providing the magnet for trapping abraded powder in
the connecting passage between an opening of a bearing and the outside of
the motor.