Hard disk drive having a disk fluttering reducing unit that uses an air damping effect to reduce the fluttering of a rotation disk

摘要

A hard disk drive having a disk fluttering reducing unit includes a lower air damper forming member provided on an upper surface of a base plate to face a bottom surface of an outer circumferential side of the disk, and an upper air damper forming member provided on a bottom surface of a cover plate to face an upper surface of an outer circumferential side of the disk. At least one air compression surface is inclined in a circumferential direction of the disk so that a gap formed between the disk and the corresponding air damper forming members decreases along a rotational direction of the disk and is formed at each of surfaces of the air damper forming members facing the disk. The air compression surface is inclined in a radial direction of the disk so that the gap decreases from an inner circumferential side of the disk to an outer circumferential side of the disk. When at least two disks are provided, a middle air damper forming member disposed between the two disks is provided. Thus, disk fluttering is reduced by an air damping operation of the disk fluttering reducing unit so that a reliability of data recording and reproducing is improved.