Automatic balance device for disk

Details Automatic balance device for disk Automatic balance device for disk

2000-06-02

2002-12-10

Klimowicz, William (Department: 2652)

Dynamic information storage or retrieval

Dynamic mechanism subsystem

Specific detail of storage medium support or motion production

C074S573110

Reexamination Certificate

active

06493311

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to an automatic balance device for disk, especially to an automatic balance device for disk, which comprises rolling beads of different sizes.
BACKGROUND OF THE INVENTION
The conventional CD-ROM driver, as shown in
FIG. 1
, mainly comprises a base
10
, a stage
11
, a pick-up head
12
, a spindle motor
13
and a turntable
14
. The stage
11
is mounted on the base
10
through a plurality of flexible supports
15
. The pick-up head
12
and the spindle motor
13
are placed on the stage
11
and the turntable
14
is fixed on top of the spindle motor
13
. An optical disk
16
is mounted on the turntable
14
and is clamped by a clamping chassis
17
. The turntable
14
is driven to rotate by the spindle motor
13
, and the disk
16
on the turntable
14
is also rotated for accessing data thereon.
In order to reduce vibration and noise for a disk with unbalanced mass, the conventional CD-ROM driver is generally equipped with automatic balance devices. The automatic balance devices are classified as magnetic type and non-magnetic type.
As shown in
FIG. 2
, the non-magnetic type automatic balance devices for CD-ROM driver comprises a plurality of rolling beads
18
within the turntable
14
or the clamping chassis
17
and of the same size. The plurality of rolling beads
18
are functioned to compensate the imbalance force of the disk
16
. However, when the disk starts to rotate, the rolling beads
18
are rolled toward the same orientation of the mass center of the disk with unbalanced mass. Therefore, the disk with unbalanced mass will have larger angular momentum when. beginning to rotate. This is the first drawback of the non-magnetic type automatic balance devices for CD-ROM driver. When the rotation angular frequency of the disk
16
exceeds the natural frequency of the composite structure of the stage
11
and the flexible supports
15
, theoretically the rolling beads
18
will be rolled toward direction opposite to the mass center of the disk with unbalanced mass. However, the rolling beads
18
is subject to large frictional force due to large centrifugal force thereof. The rolling beads
18
have not sufficient kinetic energy to reach the designed position for eliminating the imbalance force of the disk
16
, and the vibration and noise problems are worsened. This is the second drawback of the non-magnetic type automatic balance devices for CD-ROM driver.
As shown in
FIG. 3
, the magnetic type automatic balance devices for CD-ROM driver comprises a plurality of rolling beads
18
of same size and a magnetic piece
19
within the turntable
14
or the clamping chassis
17
. The plurality of rolling beads
18
are functioned to compensate the imbalance force of the disk
16
. The conventional magnetic type automatic balance devices for CD-ROM driver can be of dual-pole configuration or quadruple-pole configuration, as shown in
FIGS. 4 and 5
, respectively. When the disk starts to rotate, the rolling beads
18
are attracted by the magnetic piece
19
and not rolled toward the same orientation of the mass center of the disk with unbalanced mass, thus preventing worsened vibration and noise. When the rotation angular frequency of the disk
16
exceeds the natural frequency of the composite structure of the stage
11
and the flexible supports
15
, the rolling beads
18
will be released from the magnetic piece
19
and rolled toward direction opposite to the inclined direction of the disk with unbalanced mass. However, the rolling beads
18
are of the same size, those rolling beads
18
will be released at the same time. If the rolling beads
18
are released to wrong positions, the rolling beads
18
cannot move to proper positions for eliminating the imbalance force of the disk
16
. The rolling beads
18
have considerable frictional force with respect to the turntable
14
due to the large centrifugal force thereof. The rolling beads
18
will have no chance to gain energy to move to proper positions for eliminating the imbalance force of the disk
16
.
It is the object of the invention to provide an automatic balance device for disk, by which the vibration and noise of the disk can substantially be eliminated.
To achieve the above object, the present invention provide an automatic balance device for disk, which comprises a plurality of rolling beads of different sizes and a magnetic piece within the turntable or clamping chassis of the CD-ROM driver. The rolling beads of different sizes will be released from the magnetic piece at different rotating speed of disk. Therefore, the rolling beads with larger weight are first released from the magnetic piece and then bumped by the rolling beads with smaller weight, which are released from the magnetic piece at later time. The rolling beads with larger weight can be moved to desired position to counteract the imbalance force of the disk.


REFERENCES:
patent: 6243351 (2001-06-01), Huang
patent: 11113213 (1999-04-01), None
patent: 11341777 (1999-12-01), None
patent: 2000030355 (2000-01-01), None
patent: 2000036148 (2000-02-01), None
patent: 20000102211 (2000-04-01), None

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