JP2000040281A - Disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk device capable of efficiently canceling an imbalance, preventing the generation of unnecessary noises, and inducing no errors during speed switching or speeding-up, regarding a technology for canceling the imbalance of a disk by using a spherical body. SOLUTION: This disk device is provided with a sub-base 6, a main base 8, a turntable 9 and a balancer composed of a magnet 27 and a spherical body 13 and adapted to cancel the imbalance of a disk 1 by using the motion of the spherical body 13. As the magnet 27 incorporated in a clamper 10 for holding the disk 1, one polarized into four or more poles in a rotational direction and magnetized, one polarized and magnetized in the rotary axial direction and one polarized and one polarized and magnetized in the radial direction are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device equipped with a vibration suppressing device for suppressing self-vibration due to unbalance of a disk serving as a recording medium to enable stable recording and reproduction.

[0002]

2. Description of the Related Art Recently, CD-ROM drives and CD-Rs have been developed.
2. Description of the Related Art Data transfer speeds have been increasing in disk devices for recording and reproducing data, such as drives, and in order to transfer data at high speed, it is necessary to rotate the disk at a high distance. In general, there are many unbalanced disks with uneven mass balance due to uneven thickness, etc.When such a disk is rotated at high speed, the unbalance force of the disk acts and self-vibration occurs,
The vibrations are transmitted to the entire device, making it impossible to reproduce data stably, generating noise due to the vibrations, shortening the life of the motor, and transmitting the vibrations to other peripheral devices when the drive is built into the computer. And have adverse effects. Therefore, in order to speed up data transfer by rotating the disk at high speed, it is necessary to suppress self-vibration due to disk imbalance.
Various measures have been taken to cancel the imbalance.

A conventionally known disk device having a function of canceling imbalance will be described below. FIG. 7 is a perspective view showing a disk device equipped with a balancer for canceling imbalance. Reference numeral 1 denotes a disk which is mounted on a turntable 9 and driven to rotate by a spindle motor 2, and an optical pickup 3 reads data recorded on the disk 1 and writes data on the disk 1. The rotation of the optical pickup drive motor 4 is converted into linear motion by the action of the optical pickup drive system 5, and the optical pickup 3 slides in the radial direction of the disk 1. These mechanical systems are all mounted on the sub base 6, and the sub base 6 is connected to the main base 8 by an insulator 7 of a low rigidity elastic body.
Vibrations transmitted from the outside are attenuated by the insulator 7. The disk 1 is held by a turntable 9 and a clamper 10 which rotate integrally with the spindle motor 2 and rotates. The resonance frequency of the vibration of the sub base 6 due to the deformation of the insulator 7 when the disk 1 rotates at high speed is set lower than the rotation frequency of the disk 1 at high speed.

FIG. 8 is a sectional view of the vicinity of the spindle motor 2 showing details of a balancer integrally formed with the clamper 10 of the disk device. A magnetic yoke 11 made of a magnetic material is fixed to the turntable 9 and rotates integrally with the spindle motor 2. The clamper 10 has a magnet 27 built therein, and the disk 1 is sandwiched by the magnetic attraction force of the magnetic flux between the magnet 27 and the yoke 11 and rotates integrally. Magnetized surface 2 of normal magnet 27
8 is magnetized in two poles for the sake of simplicity in the manufacturing method and simple application. Reference numeral 15 denotes a back yoke made of a metallic magnetic material, which is attracted and fixed to the non-magnetized surface 29 of the magnet 27 to block magnetic flux leaking from other than the magnetized surface 28, thereby increasing the efficiency of the attractive force to the disk 1. A plurality of magnetic spheres 13 are rollably accommodated in the clamper 10. 13a shows the position of the sphere 13 at the time of high-speed rotation, and 13b shows the position of the sphere 13 at the time of low-speed rotation. These balancer components are mounted on a sub-base 6, and the sub-base 6 is connected to a main base 8 through an insulator 7, and as described above, the sub-base 6 is deformed when the disk 1 rotates at a high speed. The resonance frequency of the vibration 6 is set lower than the rotation frequency of the disk 1 at high speed.

FIG. 9 is a cross-sectional view of the clamper 10 seen from above, showing that the imbalance is canceled when the disk rotates at a high speed due to the movement of the sphere 13 housed inside the clamper 10. The state of the sphere 13 when the unbalanced disk 1 is rotated at a low speed and the cancellation of the unbalance of the disk 1 when the disk 1 is rotated at a high speed will be described with reference to FIGS. 8 and 9.

Normally, in a CD-ROM drive, the disk 1 is rotated at a high speed (up to about 4200 rpm in an 8 × -distance mode) in order to increase the transfer speed at the time of data reading.
00 rpm). As described above, a high-speed rotation range such as data reading and a low-speed rotation range such as audio play are mixed.

When the unbalanced disk 1 is rotated at high speed, an unbalance force 18 as a centrifugal force acts on the center of gravity 17 of the disk 1, and the acting direction rotates together with the disk 1. The insulator 7 is deformed by the unbalance force 18, and the sub base 6 swings at the rotation frequency of the disk 1. As described above, since the resonance frequency of the vibration of the sub-base 6 is set lower than the rotation frequency of the disk 1, the direction of the displacement of the sub-base 6 and the direction of the unbalance force are always opposite. Therefore, clamper 1
The centrifugal force 19 and the rolling surface 2 on which the sphere 13 is pressed and rolled are applied to the plurality of spheres 13 stored so as to be rollable to zero.
A moving force 22, which is a resultant force of a drag 21 from 0, acts, and the sphere 13 moves in a direction away from the whirling center 23, gathers in a direction exactly opposite to the direction of the unbalance force 18, and finally gathers. The unbalance amount of the disk 1 is canceled by the total mass of the sphere 13a.

On the other hand, the sphere 1
3, the ball 13 is not pressed against the rolling surface 20 due to the shortage of the centrifugal force 19, and the location of the ball 13 becomes unstable.
Unnecessary noises such as a rolling noise of the sphere 13, a sliding noise between the sphere 13 and the inner surface of the clamper 10, and a collision noise between the spheres 13 are generated. In order to prevent this, the sphere 13 is made of a metal magnetic material, and the sphere 13 is formed by using the leakage magnetic flux 24 of the magnet 27 and the magnetic flux 25 from the magnetized surface 28 to the back yoke 15.
The unnecessary noise is prevented by directly adsorbing the outer peripheral surface 26 and the back yoke 15 to stabilize the location of the sphere 13b.

[0009]

However, in the above configuration, the following problem occurs when the rotation of the disk 1 changes rapidly from high speed to low speed. In general, some CD-ROM discs contain both data and audio on a single disc. When such discs are played, data is read at high speed, and the speed is immediately reduced to the standard speed to reproduce the audio. Is performed. That is, while the disc is rotating at high speed, it suddenly switches to low speed, and immediately after that, audio play must be performed.

As described above, at high speed, the sphere 13 rotates integrally with the clamper 10 while being pressed against the rolling surface 20 in order to cancel the imbalance of the disk 1, but the rotation speed falls to a predetermined rotation speed. And the centrifugal force acting on the sphere 13 is insufficient, and the leakage magnetic flux 24
The sphere 13 is attracted to the outer peripheral surface 26 of the magnet 27 and the back yoke 15 by the action of the magnetic flux 25 from the magnetized surface 28 to the back yoke 15. However, as mentioned above, magnet 2
The magnetized surface 28 is magnetized to two poles. In the case of the two-pole magnetized, the leakage magnetic flux 24 is large and the magnetic flux 25 has a small magnetic flux density. Therefore, the sphere 13 is the disk 1
When the speed changes from low-speed rotation to high-speed rotation, the magnet 27
It is difficult to separate from the outer peripheral surface 26 of the magnet 27 unless the centrifugal force 19 acting on the sphere 13 changes considerably from high-speed rotation to low-distant rotation. It becomes difficult to adsorb. As described above, in the case where the operation is shifted to the audio play immediately after the data read at the high speed rotation, the sphere 13 is attracted to the outer peripheral surface 26 of the magnet 27 after the start of the audio data read due to the characteristic that the sphere 13 is difficult to separate and attract. The shock at the time of the suction is transmitted to the disk 1 and causes a read error.

At the start of disk rotation, that is, at the time of spin-up, after the rotation speed becomes sufficiently high due to the characteristic that the sphere 13 is hard to separate from the outer peripheral surface 26 of the magnet 27 due to the effect of the large leakage magnetic flux 24, As a result, the collision with the rolling surface causes an increase in the impact, which causes a failure such as a spin-up time over.

SUMMARY OF THE INVENTION In view of the above problems, the present invention utilizes the centrifugal force of a sphere to efficiently cancel the imbalance of a disk during high-speed rotation where the unbalance of the disk becomes a problem. It is an object of the present invention to provide a disk device that does not induce an error when the number of rotations of the disk suddenly changes from a high-speed rotation to a low-speed read or when spin-up is performed, while stabilizing the noise and preventing the generation of unnecessary noise.

[0013]

In order to solve the above-mentioned problems, a disk drive according to the present invention is provided as a means for efficiently canceling imbalance of a disk, and is provided so as to be rotatable integrally with the mounted disk, A disk device comprising: a balancer having a hollow annular portion in which a body is accommodated; and a magnetic field generating means for attracting and holding the magnetic body, wherein at least one of the following configurations (1) to (3) is provided. Have.

(1) The magnetic field generating means is a magnet arranged on the inner peripheral side of the hollow annular portion and polarized and magnetized to four or more poles in the rotational direction. (2) The magnetic field generating means is a magnet arranged on the inner peripheral side of the hollow annular portion and polarized and magnetized in the rotation axis direction. (3) The magnetic field generating means is a magnet arranged on the inner peripheral side of the hollow annular portion and polarized and magnetized in the radial direction.

According to the present invention, a magnet which is polarized as four or more poles in a rotational direction, a magnet polarized in a rotational axis direction, or a magnet polarized in a radial direction is used as a magnetic field generating means. By using this, the influence of the leakage magnetic flux received from the magnet on the magnetic material is reduced, and the imbalance of the disk is efficiently canceled. According to the present invention, when the disk is rotated at a low speed, even if the centrifugal force acting on the magnetic material is small and unstable magnetic material is caused by the magnetic flux leakage, the magnetic material is not easily affected by the magnetic flux leakage, so that the magnetic flux is not easily affected. It is possible to cancel the imbalance force of the disk.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In the configuration of each embodiment described below, the same components as those of the above-described conventional device are denoted by the same reference numerals. FIG. 1 is a view showing a first embodiment of the present invention, FIG. 1a is a sectional view, and FIG. 1b is a plan view of a magnet.

Numeral 13 denotes a metal magnetic sphere which is composed of a plurality of clampers 1 for canceling imbalance of the disk 1.
0 so that it can roll. 13a indicates the position of the sphere 13 during high-speed rotation, and 13b indicates the position of the sphere 13 during low-speed rotation and when stopped. Reference numeral 27 denotes a magnet whose magnetized surface 28 is magnetized by being polarized to four poles, forms a magnetic path in the direction of the yoke 11, and holds the disk 1 with the turntable 9 each time the yoke 11 is attracted. ing. In FIG. 9 showing the structure of the two-pole magnetization, the circumference of the magnet 27 is divided into 180 degrees by an S pole and an N pole, whereas in the case of four pole magnetization, as shown in FIG. 1B. In addition, the S pole and the N pole are alternately divided into four poles at 90 ° in the circumferential direction and arranged. The magnetic attractive force of the magnet 27 with respect to the yoke 11 is set to be equal to that in the case of two-pole magnetization. Reference numeral 15 denotes a back yoke which is attracted and fixed to the non-magnetized surface 29 of the magnet 27 and has an outer diameter sufficiently larger than the outer diameter of the magnet 27. Reference numeral 24 denotes a magnetic flux leaking from the magnet 27, and reference numeral 25 denotes the back yoke 15
Shows the magnetic flux to

In the first embodiment of the present invention configured as described above, when the disk 1 rotates at a high speed,
The operation when rotating at low speed will be described. As in the conventional disk drive shown in FIG. 9, when the unbalanced disk 1 is rotated during high-speed rotation such as data reading, a centrifugal force 19 from the whirling center acts on the sphere 13 to press it against the rolling surface 20. Move while rolling
And stops at a position where the unbalance force is balanced with the unbalance direction, and rotates together with the clamper 10 to cancel the unbalance of the disk 1.

On the other hand, the disc 1 is used for audio play.
When the rotation speed changes from the high-speed rotation to the low-speed rotation, the centrifugal force 19 acting on the sphere 13 becomes insufficient and the sphere 13
The spherical body 13 is separated from the outer peripheral surface 26 of the magnet 27 and the back yoke 1 by the action of the magnetic flux 24 of the magnet 27 and the magnetic flux 25 from the magnet 27 to the back yoke 15.
Adsorb to 5.

Here, in the above embodiment, the magnet 2
Since the magnetized surface 28 of the magnet 7 is magnetized in four poles, the state of the magnetic flux is much smaller than in the case of magnetized in two poles, and the leakage magnetic flux 24 near the outer peripheral surface 26 of the magnet 27 becomes very small. The magnetic flux density of magnetic flux 25 from 28 to back yoke 15 increases. As a result, the movement of the sphere 13 is
The magnet 27 is easily separated and attracted. When the disk 1 suddenly changes from a high-speed rotation to a low-speed rotation due to this characteristic, the sphere 13 is moved to the magnet 2 with a quick timing.
7 can be adsorbed. In other words, since the sphere 13 is attracted before moving to the read of audio data, no data read error occurs due to the impact at the time of the attraction. In addition, since the leakage magnetic flux 24 is small, the impact when the sphere 13 is attracted is also small.

At the time of spin-up, the sphere 13 is easily separated from the magnet 27 and separates at an early timing, and the impact due to the collision with the rolling surface is much smaller than that of the two-pole magnetization. Can be greatly reduced. FIG. 2 shows a graph demonstrating the function of the first embodiment. (A) on the upper side of the figure shows the characteristics when the balancer using the magnet magnetized to four poles of the above embodiment is used, and (B) on the lower side of the figure shows the conventional two-pole magnetized magnet. The characteristics of the balancer used are shown. In each figure, reference numeral 33 denotes an audio data read (Re
ad Signal) start point, 34 is magnet 2 of sphere 13
Tracking Error Signal (Tracking Err)
or Signal). 35 represents the voltage variation of the spindle motor _{2 (Spindle Motor V M Signal)} , fall portion of this 35 indicates a switching timing to the low speed from high speed. The timing relationship between the point at which the sphere 13 collides with the magnet 27 and the start point of reading audio data when the rotational speed of the disc 1 suddenly changes can be seen from the positional relationship among these 33, 34, and 35.

Comparing the graphs (A) and (B) in FIG. 2, the sphere 13 is attracted to the magnet 27 in the two-pole magnetized balancer shown in FIG. Since the timing is late, the sphere 13 collides with the magnet 27 after the start of data reading.
For this reason, a tracking error signal, which is a factor that induces an error when reproducing audio data, is very rampant. On the other hand, in the (A) quadrupole-balanced balancer, the disk 1
The sphere 13 is separated from the rolling surface 20 and is attracted to the magnet 27 at the same time as the rotation of the sphere is switched from high speed to low speed. Therefore, since the tracking error signal occurs before the start of audio data reading, no error occurs. [Axial Polarization, Radial Polarization] FIGS. 3 to 6 show the second and third embodiments of the present invention. The same reference numerals are given to the same structures as those of the above-described embodiment, and redundant detailed description will be omitted.

In the embodiment shown in FIG.
3 is rotatably accommodated in the clamper 10.
13a indicates the position of the sphere 13 at high speed and low speed rotation,
13b shows the position of the sphere 13 at the time of stop. The magnetized surface 28 of the magnet 27 has the same pole (S pole in the figure) on the entire surface.
, And the entire non-magnetized surface 29 has a pole (N pole) opposite to the magnetized surface 28. In other words, the magnet 27 is polarized and magnetized in the directions of the upper and lower rotation axes of the clamper 10. As a result, the magnetic path is formed in the direction of the yoke 11 and the yoke 11 is attracted to hold the disk 1 with the turntable 9. The magnetic attractive force of the magnet 27 with respect to the yoke 11 is set to be equal to that in the case of two-pole magnetization. Reference numeral 24 denotes a leakage magnetic flux from the magnet 27.

In the embodiment shown in FIGS. 4 to 6, the magnet 27 is polarized and magnetized in the radial direction. As shown in FIG. 5, the upper surface of the magnet 27, that is, the non-magnetized surface 29
In the planar shape of the side, the N pole is arranged concentrically on the inner peripheral side and the S pole is arranged concentrically on the outer peripheral side. As schematically shown in FIG. 6a,
Since the front and rear sides of the magnet 27 have opposite poles, on the magnetized surface 28, the N pole is arranged concentrically on the inner periphery and the S pole is arranged concentrically on the outer periphery. Note that, as shown in FIG.
The same function is achieved even if the poles and the N poles are reversed.

As described above, when the magnet 27 is polarized in the axial direction or the radial direction, the magnet 27
The leakage magnetic flux 24 in the vicinity of the rolling surface 20 becomes very small.
Therefore, even when the centrifugal force is reduced, the spherical body 13 is hardly affected by the leakage magnetic flux, so that the imbalance can be canceled as in the case of the high-speed rotation. Also, at the time of spin-up, the sphere 13 is brought into contact with the rolling surface 20 at an early timing.
As a result, the impact due to the collision with the rolling surface is much smaller than in the case of two-pole magnetization, so that an error-inducing factor such as a servo deviation can be greatly reduced.

FIG. 10 shows a conventional disk drive with 2
FIG. 10 shows the effect of the magnetized magnet 27 on the sphere 13 when the unbalanced disc is rotated at a low speed such as DVD double speed (FIG. 10a). Since the number 19 is reduced, the sphere 13 is hard to move in the direction to cancel the imbalance. Furthermore, the leakage flux 2 of the magnet 27
4 is large, the sphere 13 cannot move over the magnetic flux barrier 24a during the high-speed rotation shown in FIG. 10b, and the imbalance cannot be canceled.

On the other hand, when the polarization in the radial direction or the polarization in the axial direction is performed, the leakage magnetic flux 24 becomes small, so that the above-mentioned problem is solved. In addition, since the leakage magnetic flux 24 is uniformly present on the entire circumference of the magnet 27, the magnetic flux 24a as in the case of the above-described two-pole magnetization is used.
(See FIG. 10b) does not occur, and the sphere 13 can move smoothly in the circumferential direction.

By adopting the technique of the axial polarization or the radial polarization according to the present invention, the same effect as that of the quadrupole embodiment shown in FIG. 2A can be obtained.

[0029]

As described above, according to the disk apparatus of the present invention, stable data reproduction and recording can be performed even when an unbalanced disk is rotated at a high speed, and unnecessary noise is generated at a low speed such as audio play. In addition to suppressing the occurrence, the timing of the collision of the sphere with the magnet or rolling surface when the rotation speed changes suddenly is accelerated, and the error such as lead error and spin-up time over is generated by suppressing the impact due to the collision. Can be realized.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing the vicinity of a spindle motor of a disk device and a plan view of a magnet, showing an embodiment of the present invention.

FIG. 2 is a graph comparing the timing of movement of a sphere and the start of lead.

FIG. 3 is a side cross-sectional view showing the vicinity of a spindle motor of a disk device according to another embodiment.

FIG. 4 is a side cross-sectional view showing the vicinity of a spindle motor of a disk device according to another embodiment.

FIG. 5 is a horizontal sectional view of a clamper in the apparatus of FIG.

FIG. 6 is a schematic vertical sectional view of a clamper in the apparatus of FIG.

FIG. 7 is a perspective view showing a conventional disk device.

FIG. 8 is a side sectional view showing the vicinity of a spindle motor of a disk device having a conventional balancer.

FIG. 9 is a cross-sectional plan view showing the operation of the balancer.

FIG. 10 is a cross-sectional plan view showing the effect of leakage magnetic flux on a sphere in a two-pole magnetized disk device.

[Explanation of symbols]

 Reference Signs List 1 disc 2 spindle motor 3 optical pickup 4 optical pickup driving motor 5 optical pickup driving system 6 sub base 7 insulator 8 main base 9 turntable 10 clamper 11 yoke 13 sphere 15 back yoke 17 center of gravity of disc 18 unbalance force 19 centrifugal force 20 Rolling surface 21 Drag 22 Moving force 23 Whirling center 24 Leakage magnetic flux 25 Magnetic flux 26 Outer peripheral surface of magnet 27 Magnet 28 Magnetized surface 29 Non-magnetized surface

Claims (3)

[Claims] 1. A disk comprising: a balancer provided rotatably integrally with a mounted disk and having a hollow annular portion accommodating a magnetic material; and a magnetic field generating means for attracting and holding the magnetic material. The disk device, wherein the magnetic field generating means is a magnet disposed on the inner peripheral side of the hollow annular portion and polarized and magnetized to four or more poles in a rotation direction. 2. A disk provided with a balancer having a hollow annular portion accommodating a magnetic material and rotatably provided integrally with a mounted disk, and a magnetic field generating means for attracting and holding the magnetic material. The disk device, wherein the magnetic field generating means is a magnet disposed on the inner peripheral side of the hollow annular portion and polarized and magnetized in a rotation axis direction. 3. A disk comprising: a balancer provided rotatably integrally with a mounted disk and having a hollow annular portion accommodating a magnetic material; and a magnetic field generating means for attracting and holding the magnetic material. A disk device, wherein the magnetic field generating means is a magnet disposed radially inward of the hollow annular portion and magnetized in a radial direction.