| 摘要 |
PURPOSE:To prevent vibration of rotation of a disk and to miniaturize the disk and to heighten the density of a track by providing tapered parts at the end of a hub center hole and a tapered projection that engages with the tapered part of the hub center hole at the center of rotation on a turntable. CONSTITUTION:Tapered parts 2a2, 2a3 are provided at both ends of the hub center hole of the body 2a of a hub, and iron cylinders 22 are buried in the upper and lower faces 2a1, 2a5. The shaft 4a of a turntable driving motor 4 has a tapered part 4a' at the tip and passes through the center hole 3a of the turntable 3 to project on the surface of the table 3b. This tapered part 4a' has the dimension and shape that conform to tapered parts 2a2, 2a3 of the body 2a of the hub, and the position of center of rotation of a disk 1 coincides with that of the shaft 4a by engaging with each other. Thus, that disk 1 rotates stably without causing vibration of face, and prevents the position shift of a magnetic head 7 and track and the recording capacity of the disk can be increased by increase of density of the track. |
