Patent ID: 8854767

Claim:
A disk drive device, comprising: a rotor on which a recording disk is to be mounted; and a fixed body rotatably supporting the rotor through a bearing unit, wherein the rotor includes: a projecting portion configured to fit into a central hole of the recording disk; a clamper configured to be fixed to the projecting portion; and a seating portion provided radially outward of the projecting portion, wherein the projecting portion and the seating portion are configured such that the seating portion moves with respect to the projecting portion by fixing the clamper to the projecting portion with the recording disk being in between the clamper and the seating portion, and wherein, in the case where a position, in an axial direction, of the seating portion with respect to the projecting portion is called a seating portion position, the difference between (i) the seating portion position in the case where the clamper is fixed to the projecting portion with the recording disk being in between the clamper and the seating portion, and (ii) the seating portion position otherwise is in the range from 15 μm to 35 μm.