Disk drive having an inwardly radially spring loaded hard ring disk pack attachment to the disk motor rotor

A hard disk assembly for a disk drive, comprising:

• a. a rotatable member having a substantially cylindrical body and a peripheral shoulder adjacent one end thereof;
• b. a disk hub having opposite hub faces and a central circular opening therethrough between said opposite hub faces, said circular opening of said hub having an upper circular edge at each hub face of said opposite hub faces, said cylindrical body projecting through said circular opening in said disk hub, one hub face of said opposite hub faces being seated upon said peripheral shoulder;
• c. at least one disk concentrically mounted to said disk hub;
• d. said cylindrical body having a circumferential groove therein having an upper circumferential groove edge, a lower circumferential groove edge, a circumferential groove bottom and an upper conical groove surface sloping downwardly and inwardly of said cylindrical body from said upper circumferential groove edge to said circumferential groove bottom, said lower circumferential groove edge being disposed below said upper circular edge of said circular opening in said hub, and
• e. a spring ring of hard material disposed in said circumferential groove and in contact ones with said upper conical groove surface and with said disk hub, said spring ring having a planform inside diameter which is less than the diameter of said cylindrical body and greater than the diameter of said circumferential groove bottom, said inside diameter of said spring ring being expandable to fit over said cylindrical body and to snap into said circumferential groove, said spring ring being retained by inwardly directed radial spring force in said circumferential groove in contact with said upper conical groove surface in said cylindrical body and in contact with said disk hub and applying a spring force to said hub, said spring force having an axial component acting on said hub for securing said hub to said, external peripheral shoulder of said cylindrical body.