Disk stack assembly with spindle motor hub having improved disk-supporting flange

A hard disk drive (HDD) disk stack assembly comprising:

• a hub having an outer cylindrical surface, the cylindrical surface being centered along a hub central axis;
• a flange extending from the outer cylindrical surface of the hub, the flange having a generally conical surface defined by a radially inner circular ridge and a radially outer circular edge;
• a 65 mm diameter disk having its radially inner portion on the flange and in contact with the radially inner circular ridge of the flange, whereby the flange conical surface diverges away from the disk in the radially outward direction;
• and
• a clamp attached to the hub for clamping the disk, the clamp having a clamp contact rim;
• wherein the radially inner circular ridge is axially spaced from the clamp contact rim and the radially outer circular edge is axially spaced from the clamp contact rim by a distance between 2 and 4 microns greater than the axial spacing of the inner circular ridge from the clamp contact rim.

A disk stack assembly for attachment to a disk drive spindle motor having an axis of rotation, the assembly comprising:

• a spindle motor hub having a central axis coincident with the spindle motor axis when mounted on the spindle motor and an outer cylindrical surface;
• a flange extending from the outer cylindrical surface of the hub for supporting a disk, the flange having a generally conical surface defined by a radially inner circular ridge and a radially outer circular edge;
• a 65 mm diameter disk having its radially inner portion on the flange and in contact with the ridge, whereby the flange conical surface diverges away from the disk in the radially outward direction;
• a disk spacer ring on the radially inner portion of the disk;
• and
• a clamp attached to the hub and having a clamping surface for clamping the spacer ring and disk;
• wherein the radially inner circular ridge is axially spaced from the clamp clamping surface and the radially outer circular edge is axially spaced from the clamp clamping surface by a distance between 2 and 4 microns greater than the axial spacing of the inner circular ridge from the clamp clamping surface.