Dynamic information storage or retrieval – Dynamic mechanism subsystem – Specific detail of storage medium support or motion production
Reexamination Certificate
2000-05-05
2004-08-10
Cao, Allen (Department: 2652)
Dynamic information storage or retrieval
Dynamic mechanism subsystem
Specific detail of storage medium support or motion production
Reexamination Certificate
active
06775224
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotor balancer and a disk drive or driver having the rotor balancer, and more particularly, to a rotor balancer and a disk drive or driver having the rotor balancer which is capable of simplifying a construction of an auto balancing unit for automatically correcting a rotation unbalance occurring when a disk is rotated and a mounting unit for accurately mounting the disk, while reducing a noise and a vibration.
2. Description of the Background Art
Generally, when a rotor for rotating a rotation-object member is rotated, a rotation unbalance may occur from various causes. In order to remove such rotation unbalance problem, a rotor balancer is provided.
The rotor balancer is used for various devices. In the following description, the rotor balancer is taken an example for a disk driver for recording and reproducing a signal on and from a disk such as a CD or a DVD.
Recently, as the disk driver is designed to rotate at a high speed, a disk rotation unbalance problem occurs when a disk is rotated at a high speed.
Such rotation unbalance of the disk makes it difficult to accurately reproduce a signal recorded from the disk or to accurately record a signal on the disk.
The rotation unbalance of the disk is mostly caused due to unbalance of the disk itself (in case that there is a mass eccentricity) when the disk is fabricated, and especially it comes as a more serious problem when the disk is rotated at a high speed.
In addition, the rotation unbalance may occur in case that the disk is not accurately mounted on a turntable.
In order to solve the rotation unbalance of the disk, a balancer is provided to a mounting unit on which the disk is mounted, to a clamp for holding the disk, or to a spindle motor for rotating the disk.
A rotor balancer used for a disk driver in accordance with a conventional art will now be described with reference to the accompanying drawings.
FIG. 1
is a sectional view showing a construction of a disk driver having a rotor balancer in accordance with a conventional art.
As shown in the drawing, at the lower portion of the rotational shaft
1
, there are provided a spindle motor
3
for rotating a disk (not shown) by providing a rotor
2
that is rotated along with a rotational shaft
1
and an auto balancing unit for correcting a rotation unbalance when the disk (not shown) is rotated at the side of the spindle motor
3
.
The auto balancing unit includes a ball case
4
having a circular racing space, a magnet
5
having a predetermined size positioned at one side in the ball case
4
, and a plurality of metallic balls for correcting a rotation unbalance when the disk is rotated positioned at the space
6
between the inner circumferential surface of the ball case
4
and the magnet
5
.
The magnet
5
normally serves to prevent the ball
7
from moving freely in the space
6
.
The inner circumferential surface of the ball case
4
becomes the outer racing face
8
a
on which the ball
7
travels, and the surface of the magnet
5
becomes the inner racing face
8
b
on which the ball
7
travels.
Meanwhile, at the upper portion of the rotational shaft
1
, there is provided a mounting unit including a turntable
9
on which a disk (not shown) is mounted, an insert portion formed as an insert cone
10
installed at the upper end of the rotational shaft
1
, for accurately fixing the disk (not shown), a mounting ring
11
installed between the turntable
9
and the insert cone
10
, and a spring
12
for elastically supporting the mounting ring
11
upwardly.
A friction member
13
is installed at a circumferential portion at the upper surface of the turntable
9
, to which a lower surface of the disk is adhered so that the disk is prevented from arbitrarily moving on the turntable
9
.
The insert cone
10
and the mounting ring
11
to which a hole (not shown) of the disk is inserted is formed of which the upper circumferential portions are sloped to a predetermined degree, to thereby facilitate insertion of the disk.
The outer diameter of the insert cone
10
is approximately 14.96 mm~14.99 mm. For reference, the inner diameter of the central hole of the general disk is approximately 15 mm~15.1 mm.
Accordingly, there is a gap of approximately 10~40 &mgr;m between the inner diameter of the hold of the disk and the outer diameter of the insert cone
10
, by which, when the disk is inserted to the insert cone
10
and is clamped by a clamp (not shown), since the disk may be mounted on the turntable
9
in an eccentric state, the disk mounting unit is installed to remove the eccentricity and the disk is centered.
Namely, centering of the disk is made in a manner that in a state that the disk is inserted into the insert cone
10
, the mounting ring
11
is upwardly supported by the spring
12
and the claim (not shown) presses down the disk.
The operation of the disk driver having the rotor balancer of the conventional art constructed as described above will now be explained with reference to
FIGS. 2A and 2B
.
FIG. 2A
is a view showing how the balls are aligned for a disk without a mass eccentricity in an auto balancing unit of a rotor balancer, in accordance with the conventional art.
FIG. 2B
is a view showing how the balls are aligned to compensate for a mass eccentricity in the auto balancing unit of the rotor balancer, in accordance with the convention art.
That is, as shown in
FIG. 2B
, for a disk ‘D’ having the mass eccentricity, the balls
7
are collected at one side of the space in the ball case
4
, correcting the mass eccentricity.
FIG. 2A
shows a disk ‘D’ without mass eccentricity. In this case, the balls
7
are evenly aligned in the space
6
of the ball case
4
.
Meanwhile, in case where the disk driver is used vertically, there is following problems due to the gravity force working on the ball
7
.
Namely, in case that the disk driver is vertically stood for use, auto balancing, which is however technically difficult, should be favorably made and the balls
7
should be auto-aligned at an early stage.
The auto-alignment refers to a state that the balls
7
are mostly positioned at the outer racing face
8
a
of the space
6
by virtue of centrifugal force of the spindle motor
3
, thereby maintaining balance.
Generally, in order to have a desirable auto balancing, the outer racing face
8
a
on which the ball
7
travels should have good asperity, concentricity and circularity, by which friction coefficient between the ball
7
and the outer racing face
8
a
should be minimized.
Meanwhile, in order to stabilize the ball
7
at an early stage, friction coefficient between the ball
7
and the outer racing face
8
a
should be great so that the disk driver may overcome the gravity force applied to the ball
7
to push up the ball
7
even in its vertically stood-up state.
Therefore, in the conventional art, due to the mutually contradictory characteristics in the auto balancing of the disk driver and the stabilization of the ball, designing was made by sacrificing either one of the two characteristics.
Resultantly, since vibration reduction absolutely affecting the basic capacity of the disk driver takes the priority for designing, the ball balancing is inevitably delayed, so that auto balancing is not made or incompletely made, causing vibration and noise.
Thus, in order to solve the problem, another method is adopted which will now be described with reference to
FIGS. 3A and 3B
.
FIG. 3A
is a partial sectional view showing a construction of an auto balancing unit provided with a protrusion for pushing up a ball in a state that a disk driver is vertically stood up in accordance with a conventional art, and Figure is a plan sectional view showing a construction and an operation of the auto balancing unit of
FIG. 3A
in accordance with the conventional art.
As shown in the drawings, in a state that the disk driver installed on a substrate
14
is vertically stood up, a protrusion
15
for pushing up the ball
7
is formed on the racing face of the ma
Cao Allen
LG Electronics Inc.
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