Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Disk record
Reexamination Certificate
2003-02-11
2004-09-14
Letscher, George J. (Department: 2653)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Disk record
Reexamination Certificate
active
06791790
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 2002-7957, filed Feb. 14, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hard disk drive, and more particularly, to a hard disk drive which can reduce vibration of a disk.
2. Description of the Related Art
A hard disk drive (HDD) is an auxiliary memory device of a computer that reads out data from a magnetic disk or records data on the disk by using a magnetic head. Recently, a variety of research and development efforts have focused on realizing a high speed, high capacity, low vibration, and low noise hard disk drive.
FIG. 1
is a perspective view showing a conventional hard disk drive.
FIG. 2
is a vertical sectional view of the hard disk drive of FIG.
1
.
Referring to
FIG. 1
, a conventional hard disk drive includes a housing
10
, a spindle motor
30
installed in the housing
10
to rotate a magnetic disk (a hard disk)
20
, and an actuator
40
having a magnetic head for recording and reading out data on and from the disk
20
. The following description relates to one magnetic disk
20
, although two are shown in
FIGS. 1 and 2
.
The housing
10
is installed in a main body of a computer and includes a base plate
11
to support the spindle motor
30
and the actuator
40
, and a cover plate
12
coupled to the base plate
11
to enclosing and protecting the disk
20
. The housing
10
is typically manufactured of a stainless steel or aluminum material.
The disk
20
is a recording medium for recording data and may be a single disk or a plurality of disks capable of being rotated by the spindle motor
30
. If a hard disk drive has a plurality of disks, they are installed to be separated a predetermined distance from each other.
Referring to
FIG. 2
, the spindle motor
30
is supported by a flange
31
fixedly installed on the base plate
11
. Typically, an upper end portion of a shaft
32
of the spindle motor
30
is fixedly coupled to the cover plate
12
by a screw
36
. A hub
33
is rotatably installed around the outer circumferential side of the shaft
32
by interposing a bearing
37
therebetween. The disk
20
is inserted around the outer circumferential side of the hub
33
. When a plurality of disks are installed, a ring type spacer
34
for maintaining a distance between the disks
20
is installed at the outer circumferential side of the hub
33
. A clamp
35
for preventing escape of the disk
20
is coupled to an upper end portion of the hub
33
.
Historically, storage capacity of hard disk drives has gradually increased. The storage capacity of a hard disk drive is proportional to a surface recoding density which is determined by the multiplication of a linear recoding density expressed by BPI (bits per inch) and a track density expressed by TPI (tracks per inch). BPI is totally affected by the development of a magnetic recording technology while TPI is mainly dependent on the improvement of a mechanical dynamic characteristic.
Track Misregistration (TMR) is a malfunction generated when data is recorded or reproduced on or from a track of a disk and is an important factor that restricts TPI and is therefore related to the storage capacity of the hard disk drive. A direct source of TMR is vibration of a disk. Disk vibration can be attributed to three sources: non-repeatable runout (NRRO) due to a defective ball bearing of the spindle motor, disk rocking motion due to gyro-moment of a rotating disk, and disk fluttering.
To increase reliability of performance of a hard disk drive by reducing TMR, disk vibration generated during operation needs to be reduced. Accordingly, as shown in
FIG. 3
, it is a recent trend to decrease a gap between the disk
20
and each of a base plate
11
′ and a cover plate
12
′ by forming the surfaces of the plates
11
′ and
12
′ facing the disk
20
to protrude toward the disk
20
. When the gap between the disk
20
and each of the plates
11
′ and
12
′ is sufficiently narrow, disk vibration is reduced by air compressed therebetween. But when the gap between the disk
20
and each of the plates
11
′ and
12
′ decreases, a relatively small external impact may cause, the disk
20
to collide against the base plate
11
′ or the cover plate
12
′, thereby damaging the disk
20
. So while the damping effect by compressed air increases as the gap between the disk
20
and each of the plates
11
′ and
12
′ decreases, the disk
20
is more easily damaged. Thus, there is a limit in reducing the gap. Typically, the gap between the disk
20
and each of the plates
11
′ and
12
′ is about 1 millimeter, which provides a damping effect by compressed air. However, a sufficient disk vibration reducing effect cannot be obtained.
SUMMARY OF THE INVENTION
To solve the above-described problems, it is an aspect of the present invention to provide a hard disk drive in which air pumping grooves for pumping air toward the outer circumferential side of a disk to reduce vibration of the disk are provided in the base plate and the cover plate.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and/or other aspects, there is provided a hard disk drive comprising a housing having a base plate and a cover plate, a spindle motor installed on the base plate, at least one data storage disk installed at the spindle motor, and an actuator, pivotably installed on the base plate and having a magnetic head recording and reading out data on and from the disk. At least one groove to pump air toward an outer circumferential side of the disk is formed in any one of the surfaces of the base plate and the cover plate which faces the disk. An outer end of the groove is located at a position inwardly separated a predetermined distance from an edge of the disk such that an air journal zone having a predetermined width is formed along a circumferential direction of the disk between the outer end of the groove and the edge of the disk. Vibration of the disk is thereby reduced by a damping operation of compressed air pumped by the groove having a high pressure in the air journal zone.
It is an aspect of the present invention that a protruding surface protruding to a predetermined height toward the disk is formed at at least one of an upper surface of the base plate and a lower surface of the cover plate to reduce a distance from the disk, and the groove is formed in the protruding surface.
It is an aspect of the present invention that the groove is formed in multiple numbers in a circumferential direction of the disk at a predetermined interval, and that the groove is extended in a radial direction from an inner circumferential side of the disk and curved in a direction in which the disk rotates.
It is an aspect of the present invention that a bottom surface of the groove is inclined toward the disk at an outer end portion of the groove.
REFERENCES:
patent: 5333079 (1994-07-01), Takegami et al.
patent: 6088190 (2000-07-01), Anderson
patent: 6236532 (2001-05-01), Yanagisawa
patent: 6466398 (2002-10-01), Butler et al.
patent: 2002/0154441 (2002-10-01), Tadepalli et al.
patent: 8293191 (1996-05-01), None
Letscher George J.
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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