| 摘要 |
PURPOSE:To hold air, which is circulated in a disc enclosure, in the dustless state by providing an air hole in a frame cover part near the rotation center of a hub and arranging a breathing filter in the air hole. CONSTITUTION:An air hole 21 is provided near the rotation center of a hub 5 of a frame cover 2 forming a disc enclosure 20, and a breathing filter 22 is arranged in the hole 21. Consequently, clean air passing through the filter 22 is taken into the enclosure 20 positively, and air is discharged to the outside from gaps of parts constituting the enclosure 20, and these gaps have a negative pressure to prevent external dusty air from flowing into the enclosure 20. As the result, air circulating in the disc enclosure is held in the dustless state. |
