Spindle motor hub assembly of hard disk drive

A disk drive spindle hub assembly, comprising:

• a spindle hub having a top portion and an enlarged spindle base, said top portion having a top end surface, a generally annular groove within said top end surface and a remaining portion of said top end surface radially outward from said annular groove forming an upwardly extending peripheral ring of a first diameter, said annular groove having an inner cylindrical wall, an outer cylindrical wall and an internal thread formed on said outer cylindrical wall;
• a stack of information storage disks journaled about said spindle hub in a spaced-apart, coaxially aligned relation, said information storage disks being coupled to said spindle hub to rotate with said spindle hub;
• spacer means positioned between adjacent ones of said information storage disks, for spacing said disks apart in the coaxially aligned relation of said spindle hub;
• a clamp spacer having an annular axial face and a central circular opening concentrically disposed on said spindle hub, said annular axial face directly facing a surface of a top information storage disk;
• and
• a disk clamp for concentrically clamping the stack of information storage disks in coaxial alignment with said spindle hub in compression against the clamp spacer, said disk clamp having a head portion, a downwardly projecting peripheral ring of a second diameter having a bottom surface sitting on said clamp spacer, and a hollow cylindrical post extending from the center of said head portion for accommodating the inner cylindrical wall of the annual groove of said spindle hub, and having an external thread formed on an outer surface for mutually engaging with the internal thread formed on the outer cylindrical wall of said annular groove of said spindle hub, when said disk clamp engages the top portion of said spindle hub for concentrically securing the stack of information storage disks to said spindle hub.