Patent ID: 8850462

Claim:
A disk drive apparatus to carry a disk having a center through hole with an inner circumferential edge, the disk drive apparatus comprising: a motor shaft having a rotation center thereof, a rotary table fit on the motor shaft, and a centering part slidably provided on the motor shaft, wherein the centering part is elastically biased in an axial direction away from the rotary table, wherein the centering part fits in the center through hole of the disk to center and hold the disk, the centering part comprising: a center taper part; outer taper parts; and outer circumferential groove parts, wherein when a first straight line is drawn at a first boundary between one of the outer taper parts and one of the outer circumferential groove parts; and when a second straight line is drawn at a second boundary between another one of the taper parts and said one of the outer circumferential groove parts, the first straight line and the second straight line form an intersection, in which, in a plan view, the intersection is located radially inside the first boundary or the second boundary, and radially outside the rotation center, wherein each of the outer taper parts has an angle smaller than that of the center taper part with respect to the motor shaft, wherein the outer taper parts and the outer circumferential groove parts are alternately provided radially outside the center taper part, wherein each of the outer taper parts abuts the inner circumferential edge of the center through hole while each of the outer circumferential groove parts provides a clearance between the inner circumferential edge and said each of the outer circumferential groove parts.