Patent ID: 8599516

Claim:
A disk drive device comprising: a hub on which a recording disk is to be mounted; a base member; a bearing unit configured to support the hub in a manner in which the hub can be relatively rotated with respect to the base member; an extended annular groove portion provided in part of the hub around the rotational axis of the hub; and a weight member that is installed in the extended annular groove portion to adjust a rotational balance when the recording disk is being rotated with the hub, and that has a fixing mechanism that is slidable, when installed, in the direction of the extended annular groove portion and that can substantially maintain a stopped state at a fixing position, wherein the weight member is configured to exert a first resisting force within the extended annular groove portion when the weight member is slid in a first extended direction within the extended annular groove portion and is configured to exert a second resisting force within the extended annular groove portion when the weight member is slid in a second extended direction opposite to the first extended direction, and said first resisting force is smaller than said second resisting force.