| 摘要 |
PURPOSE:To eliminate the distortions of a disk and to attain the disk positioning with high accuracy by providing an expanded part containing a sleeve at the tip of a rotary shaft and expanding the sleeve up to the peripheral wall of a disk hole with the fluid pressure. CONSTITUTION:A sleeve 15 made of an uniform and thin metal such as copper, etc. is coated at the tip of a rotary shaft 13 to form an expanded part. The fluid pressure of oil, water, etc. acts on a hole 13a of an axial core when a floppy disk 1 is clamped. Then the sleeve 15 is expanded in the radius direction to have a contact with the peripheral wall of a center hole 1a of a disk 1. Therefore the positioning of the disk 1 is carried out with expansion of the sleeve 15, and this state is held by a disk holder 3 and a disk receiver 14. Thus the disk 1 is free from distortions and can be positioned with high accuracy. |
