Patent ID: 8665556

Claim:
A disk drive device comprising: a hub on which a recording disk is to be mounted; a shaft that is rotated integrally with the hub; a supporting member that surrounds the shaft and that has a flange radially extending outward at the hub side edge; a base member that supports the supporting member; and a cylindrical thrust member that is rotated integrally with the hub, wherein a diameter of the shaft is 2.5 mm or less, wherein the hub is formed of a stainless material having magnetism and has an annular portion, wherein a magnet is fixed to an inner circumferential surface of the annular portion, wherein the hub has a step portion on an inner portion of the hub, wherein a top portion of the thrust member is partially affixed to the step portion of the hub in the axial direction, and wherein a part of the top portion of the thrust member not partially affixed axially faces at least part of the flange.