| 摘要 |
PURPOSE:To promote the centering accuracy of a disk and to reduce the wear of the disk by constituting the spindle hole of a hub out of a folded part made with a smooth surface. CONSTITUTION:The hub 4 provided in the central part on the outer surface of a disk substrate 1 is formed of a metal plate which is superior in wear resistance, and an inner periphery of the discoid central part is folded around to constitute this part out of the spindle hole 6. Consequently, the inner surface containing with a spindle is a smooth surface, thus promoting the centering accuracy of the disk and also reducing the degree of partial wear and damage. In addition, the hole 4 is integrated with a holder 5 made from a resin material which is superior in smooth, such as polyamide, etc., by insert molding to be fitted to the substrate 1. |
