DISK DRIVE DEVICE AND MANUFACTURING METHOD OF A DISK DRIVE DEVICE

摘要

A disk drive device includes a stationary member and a rotatable member rotatably supported by the stationary member about a rotation axis. The rotatable member includes a cylindrical part, which fits in a center hole of a recording disk, and a placement part protruding radially outward from the cylindrical part in a direction of the rotation axis. The cylindrical part includes an external thread groove formed on an outer peripheral surface thereof. The external thread groove engages with a thread groove of a clamper to clamp the recording disk. The cylindrical part includes a small inner-edge inclined surface, which is a tapered annular surface formed on an end of the cylindrical part so that the external thread groove begins forming from the small inner-edge inclined surface. The small inner-edge inclined surface has an inner circumferential edge having a diameter smaller than a thread bottom diameter of the external thread groove.

主权项

1. A disk drive device, comprising:
a stationary member including a base; and a rotatable member rotatably supported by the stationary member about a rotation axis via a dynamic pressure fluid bearing mechanism, the rotatable member including a hub having a cylindrical part configured to fit in a center hole of a recording disk and a placement part protruding radially outward from a first end portion of the cylindrical part in a direction of the rotation axis of the rotatable member, the cylindrical part including an external thread groove formed on an outer peripheral surface thereof, wherein the cylindrical part further includes a small inner-edge inclined surface, which is a tapered annular surface formed on a second end portion of the cylindrical part opposite to the first end portion so that the external thread groove begins forming from the small inner-edge inclined surface, the small inner-edge inclined surface having an inner circumferential edge at which the small inner-edge inclined surface connects to an end surface of the second end portion of the cylindrical part, the inner circumferential edge having a diameter smaller than a thread bottom diameter defined by a deepest bottom part of the external thread groove.