Disk drive base with decreased thickness portion angle being less than increased thickness portion angle

摘要

A base of a disk drive apparatus includes a bottom plate portion and a wall portion. The wall portion includes an increased thickness portion and a decreased thickness portion. An inner surface of the increased thickness portion includes a first slanting surface arranged to extend radially outward away from a central axis while extending axially away from the bottom plate portion. An inner surface of the decreased thickness portion includes a second slanting surface arranged to extend radially outward away from the central axis while extending axially away from the bottom plate portion, and protrude radially inward relative to the first slanting surface. An inclination angle of the second slanting surface with respect to an axial direction is arranged to be smaller than an inclination angle of the first slanting surface with respect to the axial direction.