Patent ID: 7106553

Claim:
A hard disk drive comprising: a housing having a base plate and a cover plate; a spindle motor installed on the base plate; a disk installed at the spindle motor to store data; an actuator installed on the base plate to be capable of pivoting and having a magnetic head to record and reproduce data on and from the disk; and a disk fluttering reducing unit forming an air damper above a surface of the disk to reduce fluttering of the disk, wherein the disk fluttering reducing unit comprises, a lower air damper forming member provided on an upper surface of the base plate to face a bottom surface of an outer circumferential side of the disk, an upper air damper forming member provided on a bottom surface of the cover plate to face an upper surface of an outer circumferential side of the disk, and at least one air compression surface inclined in a circumferential direction of the disk so that a gap formed between the disk and the lower or upper damper forming member decreases along a rotational direction of the disk and is formed at each of surfaces of the air damper forming members facing the disk, wherein the air compression surface is inclined in a radial direction of the disk so that the gap decreases in a direction from an inner circumferential side of the disk to an outer circumferential side of the disk.