| 摘要 |
PURPOSE:To attain a stable positioning control by providing plural discharge holes communicating a wind path and a space formed between magnetic disks and asymmetrically disposing said discharge holes with respect to the core of a drive control axis. CONSTITUTION:Since a magnetic disk 4 is fitted in a hub 14, tightened and fixed between the magnetic disks 5 through a ring spacer 16, a magnetic device has three spaces held by the magnetic disks 5. When they rotate, air blows out from the discharge holes 16a of the ring spacer 16, and said spaces are so formed not to be in negative pressure. Since the discharge holes 16a of the ring spacer 16 are disposed asymmetrically with respect to the axial core of the hub 14, air is discharged from each discharge hole 16a while the magnetic disks 5 rotate at prescribed rotational frequency. The level of a frequency component whose vibration stems from the number of discharge holes drops significantly, whereby a positioning control is stabilized. |
