Statically and dynamically balancing a three-disc disc stack assembly

摘要

Apparatus and method for providing static and dynamic balance in a disc drive having three recording discs. A spindle motor hub includes an outer surface which circumferentially extends about a central axis at an outer radius less than a disc inner radius. A groove is formed in the hub to provide a groove inner surface having a groove radius less than the hub outer radius. The groove radius is selected to be twice the hub outer radius minus the disc inner radius. First and third discs are loaded onto the hub and shifted to bring respective disc inner surfaces into abutment with the hub outer surface at a first angular location. The second, intermediate disc is loaded onto the hub and shifted to bring the disc inner surface into abutment with the groove inner surface at a second angular location opposite the first angular location.