JPH10208375A - Disk clamping mechanism for optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform dynamic balancing adjustment in the state of assembling a rotational drive motor into a disk clamping mechanism, in an optical disk reproducing device for reproducing information by rotating a disk medium at a high speed. SOLUTION: On a rotor 50, dynamic balance adjusting through holes 50a and 50b are formed concyclically at an equal interval respectively. The through holes 50a and 50b are positioned above a motor magnet 1, having different hole diameters in an outer circumference and an inner circumference in plural lines respectively. Then, microballs 100a and 100b formed in their diameters corresponding to these through holes 50a and 50b respectively and consisting of iron members formed by working a magnetic material are inserted into the through holes 50a and 50b respectively. Consequently, the adjustment of dynamic balance can accurately be performed. Then, the microballs 100a and 100b are attracted by magnetizing force of the motor magnet 61. Therefore, the microballs 100a and 100b are not necessary to be fixed with an adhesive for insertion to the through holes 50a and 50b, and hence the adjustment of dynamic balance can easily be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk clamp mechanism of an optical disk reproducing apparatus for recording and reproducing information by rotating a disk medium such as a so-called DVD (digital video disk) at a high speed, and more particularly to a disk clamp mechanism. And dynamic balance adjustment of the rotary drive motor.

[0002]

2. Description of the Related Art In recent years, such a recording / reproducing apparatus has been used as a CD-RO as a disk medium as a computer auxiliary storage device.
As the demand for M increases, it is required to rotate a CD-ROM at a high speed in order to cope with high-density recording and reproduction of information. The commercial value of CD-ROMs is supported by the speeding up of disk drives, and CD-ROM drives with faster data transfer speeds and access times than ever have been awarded.

In a CD-ROM drive, the rotational speed of the disk is about 200 rpm at the standard speed with respect to the outermost circumference of the disk, and at most about 530 rpm with respect to the innermost circumference of the disk.
pm, and the difference between the inner and outer circumferences of the disk is only about 330 rpm. However, the rotational drive of the disk is at the standard speed of 8
At 8x speed, the number of rotations is at least about 1600 rpm
From m to a maximum of about 4240 rpm, the difference between the inner and outer circumferences of the disk is also increased by 8 times.

Further, since the moment of inertia due to the rotation of the disk is the same irrespective of the rotation speed of the disk, if the drive torque of the disk rotation drive motor is constant regardless of the rotation speed of the disk, the adjustment time of the rotation speed, that is, The access time from when the pickup moves between the inner and outer circumferences of the disk and when the rotation speed is set to an appropriate value for reproducing the disk at a predetermined position is eight times as long.

However, in general, the drive torque of a disk rotation drive motor decreases as it rotates in a high rotation range, so that the actual access time becomes a value eight times or more. Therefore, in order to shorten the access time of the CD-ROM drive, it is necessary to increase the drive torque of the rotary drive motor.

On the other hand, as shown in FIG. 2, a disk 4 is placed on a turntable 7 for recording and reproduction of a disk.
The turntable 7 is rotated by a motor 6 and pressed by a clamper 5 from above. Generally, a laser beam is irradiated from the lower side of the disk by the pickup 3, and information is read by the reflected beam.

As described above, in order to rotate the disk 4 at high speed and shorten the access time, it is necessary to increase the diameter of the motor 6 and improve the driving torque. But,
If the motor 6 is arranged below the disk 4, it will hinder the movement of the pickup 3, and cannot have such a large diameter.

Accordingly, a motor 6 is provided on the side of the clamper mechanism for rotatably holding the disk 4, and a mechanism for pressing and holding the disk with the clamp mechanism and the turntable to rotate the disk 4 (see Japanese Patent Application Laid-Open No. 63-004642). Has been proposed, for example, as shown in FIG.

In this mechanism, a disk 4 having a hole in the center is rotatably mounted, and a turntable 7 made of a magnetic material and a turntable 7 facing the upper surface of the disk 4 are provided.
And a clamper 5 that presses the disc 4 between them. The clamper 5 is attached to a lower surface of a lid 16 provided to be freely openable and closable with respect to the turntable 7.

The turntable 7 is pressed into a rotating shaft 22 provided rotatably on a chassis 20. The turntable 7 has a cone 70 that becomes thinner toward the tip, and a hole in the center of the disc 4 fits into the cone 70.

The clamper 5 includes a projecting piece 55 supported by supporting pieces 15, 15 projecting from the lower surface of the lid 16, and a supporting piece 1.
A shaft 51 penetrating through the opening 11 between 5 and 15;
And a motor magnet 61 provided at the lower end of the disk 4 and facing the upper surface of the disk 4. At the center of the shaft 51 and the motor magnet 61, a hole 56 that fits into the rotary shaft 22 is formed. At the periphery of the opening 11, a drive coil 60 is provided to face the motor magnet 61.

When the disk 4 is placed on the turntable 7 and recording and reproduction are performed, the lid 16 is lowered, and the hole 56 of the clamper 5 is fitted to the rotary shaft 22. The turntable 7 and the motor magnet 61 attract and hold the disk 4. When the motor magnet 61 comes into contact with the cone 70, the clamper 5 is slightly lifted, and a gap is formed between the projection 55 and the drive coil 60. In this state, when the drive coil 60 is energized, the clamper 5 rotates while pressing the disk 4 by the electromagnetic force generated between the drive coil 60 and the motor magnet 61. That is, the motor magnet 61 is attracted to the turntable 7 and presses and holds the disk 4.
Face-to-face brushless motor 6 with drive coil 60
Is configured.

Further, the applicant has previously proposed a clamper mechanism shown in FIG. 4 (see Japanese Patent Application Laid-Open No. 3-286466).

The clamper mechanism has a support plate 10 provided so as to be able to approach and separate from the disk 4.
The support plate 10 is fitted in the opening 11. A drive coil 60 is attached to the periphery of the opening 11. The clamper 5 integrally includes a motor magnet 61 facing the upper surface of the drive coil 60, a shaft 51 penetrating through the opening 11, and a pressing piece 52 provided at a lower end of the shaft and in contact with the upper surface of the disk 4. The holding piece 52 is provided with a yoke 62 facing the lower surface of the drive coil 60. A sphere 90 is provided on the upper surface of the shaft 51, and the sphere 90 is in contact with the lower surface of the elastic piece 9 that covers the clamper 5.

Disk 4 mounted on turntable 7
On the other hand, when the support plate 10 is lowered, the clamper 5 slightly lifts due to the contact between the pressing piece 52 of the clamper 5 and the disk 4. A gap is created between the drive coil 60 and the motor magnet 61, and the ball 90 contacts the lower surface of the elastic piece 9. The clamper 5 is urged toward the disk 4 by the urging force from the elastic piece 9, and the clamper 5 presses and clamps the disk 4 with the turntable 7. Drive coil 6
0, the yoke 62 and the motor magnet 61
Since the drive coil 60 is located in the magnetic field therebetween, the clamper 5 rotates together with the disk 4.

Further, the applicant has filed Japanese Patent Application No. 8-13817.
No. 0 proposes a clamper mechanism that constitutes the surface facing motor shown in FIGS. 5 and 6 or the circumferential facing motor shown in FIGS. 7 and 8.

FIG. 5 is a partially cutaway view of the clamper 5 and the turntable 7 in a state where the disk 4 is not inserted into the apparatus main body. A rotating shaft 22 is rotatably fitted in a bearing 21 provided on the sub-chassis 20, and a tip end of the rotating shaft 22 is press-fitted into a through hole 71 formed in a central portion of the turntable 7. . From the upper surface of the turntable 7, a cone 70 that fits into the center hole of the disk 4 protrudes, and a magnet 8 is embedded in the upper surface of the cone 70.

The support plate 10 has an opening 11 into which the clamper 5 fits, and a drive coil 60 is attached to the periphery of the opening.

The clamper 5 includes a rotor 50 facing the upper surface of the drive coil 60, a shaft 51 attached to the center of the rotor 50 and passing through the opening 11, and a presser attached to the lower end of the shaft 51. Piece 52. The tip of the shaft body 51 projects below the holding piece 52 and can be fitted into the through hole 71 of the turntable 7. A motor gnet 61 is provided on the lower surface of the rotor 50 so as to face the drive coil 60. When the disk 4 is not inserted into the apparatus main body, the motor magnet 61 and the drive coil 60 are in contact with each other.

First, the drive coil 6 is assembled.
The rotor 50 is placed on the top of the rotor 50, the shaft body 51 and the holding piece 52 are attached from below the rotor 50, and the holding piece 52 is screwed from above the rotor 50 with screws 58, 58.

The lower surface of the holding piece 52 is in contact with the upper surface of the disk 4, and the yoke 6 made of an iron plate is
2 is mounted opposite the lower surface of the drive coil 60.

The drive coil 60 is located in a magnetic field formed between the motor magnet 61 and the yoke 62. The clamper 5 and the drive coil 60 constitute a brushless motor 6 as described later.

At the center of the holding piece 52, the turntable 7
An iron plate 80 made of a magnetic material that is attracted to the magnet 8 is embedded at a position facing the magnet 8 in the inside. The magnet 8 and the iron plate 80 are magnetically independent of the motor 6 constituted by the clamper 5 and the drive coil 60, and do not affect the characteristics of the motor 6 at all. The reason why the magnet 8 and the iron plate 80 are provided at positions corresponding to the center of the disk is to reduce the size of the magnet 8 and the iron plate 80.

FIG. 6 is a view showing a state where the disk 4 is inserted into the apparatus main body. The sub-chassis 20 rotates upward, and the turntable 7 and the clamper 5 are brought together. The clamper 5 is lifted slightly with the lower surface of the holding piece 52 in contact with the upper surface of the disk 4, and a gap is formed between the drive coil 60 and the motor magnet 61. The friction between the drive coil 60 and the motor magnet 61 is released, and the magnet 61 becomes rotatable. Since the vertical distance between the motor magnet 61 and the yoke 62 is constant, the driving torque of the motor 6 is constant even if the gap between the drive coil 60 and the motor magnet 61 varies.

When the magnet 8 approaches the iron plate 80, the magnet 8 and the iron plate 80 are attracted. Due to the suction force, the clamper 5 moves the disk 4 to the turntable 7.
To be urged.

When the drive coil 60 is energized in this state, the clamper 5 and the turntable 7 attracting the clamper 5 rotate. The disc 4 pressed and held between the clamper 5 and the turntable 7 also rotates. Pickup 3
Slides in the radial direction of the disc to perform recording and reproduction.
If the lower surface of the pressing piece 52 is pressed against the turntable 7 at a position away from the center of the disk 4, the surface runout of the disk 4 can be reduced.

As described above, the clamping of the disk 4 is performed by the attraction between the magnet 8 provided separately from the motor 6 and the iron plate 80 as a magnetic material, so that the magnetic characteristics of the motor 6 are not affected. The clamping force can be changed. Further, since the magnet 8 and the iron plate 80 are provided at positions corresponding to the holes at the center of the disk, their diameters are small. Therefore, the rotational moment of inertia caused by the provision of the magnet 8 and the iron plate 80 is small, and does not affect recording and reproduction. The magnet 8 is placed on the clamper 5 side,
0 may be provided on the turntable 7 side.

FIG. 7 and FIG. 8 show a disk clamping mechanism when a circumferentially opposed motor is employed. The configuration of the turntable 7 is the same as that in the case where the surface facing type motor is adopted. The support plate 10 has an opening 1 into which the clamper 5 fits.
1, and a stator substrate 64 is attached so as to cover the periphery of the opening 11. An iron core 63 is provided on the stator substrate 64, and a drive coil 60 is wound around the iron core 63.

The clamper 5 has a cylindrical rotor 50 with an opening facing the disk 4, and is attached to the center of the rotor 50, penetrates through the opening 11 of the support plate 10, and has a lower surface in contact with the upper surface of the disk 4. The holding piece 52 is integrally provided. A motor magnet 61 is provided on the inner peripheral surface of the rotor 50 so as to face the drive coil 60.

The pressing piece 52 has a concave portion 53 formed at the center of the lower surface, and the shaft body 51 projects downward from the center of the upper surface of the concave portion 53. The shaft 51 is provided with a through hole 71 of the turntable 7.
To prevent the clamper 5 and the turntable 7 from being displaced on a horizontal plane. In a position facing the magnet 8 in the turntable 7 in the upper surface of the concave portion 53,
An iron plate 80 to be attracted to the magnet 8 is embedded.

Therefore, when recording / reproducing the disk 4, the turntable 7 rises and the magnet 8 approaches the iron plate 80. The magnet 8 and the iron plate 80 attract each other, and the clamper 5 urges the disc 4 against the turntable 7 by the attraction force.

Incidentally, the above-described motor for rotational drive does not constitute a motor by itself, but functions only as a motor when a disk is inserted and clamped. For this reason, motor vibration generated by rotation of the rotor 50 (that is, vibration caused by the fact that the rotation center of the clamper 5 constituting the motor does not coincide with the shaft body 51) increases. This motor vibration is related to the unbalance amount of the dynamic balance of the motor. That is, since a normal motor itself is a single motor, the dynamic balance of the motor alone can be adjusted, and the adjusted motor is incorporated into the disk clamp mechanism. However, since the above-described motor for rotational driving does not constitute a motor by itself, dynamic balance adjustment must be performed in a state where the motor is incorporated in the disk clamp mechanism.

[0033]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to enable dynamic balance adjustment in a state in which a rotary driving motor is incorporated in a disk clamp mechanism.

[0034]

In order to solve the above problems, in the present invention, through holes for adjusting dynamic balance are formed in the rotor 50 at concentric circles and at equal intervals. The through holes are located above the motor magnet 61 and are provided in a plurality of rows with different hole diameters on the outer circumference and the inner circumference. Microballs formed with a magnetic material made of an iron member and having a diameter corresponding to these different hole diameters are inserted into the through holes.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is applied to the rotary drive motor described in the section of the prior art, and operates as a face-to-face motor or a circumferentially-facing motor in a state of being incorporated in a disk clamp mechanism. A technique for performing balance adjustment is disclosed.

An embodiment of the present invention will be described below with reference to the drawings. About the same structure as a conventional one, the same code | symbol is used and detailed description is abbreviate | omitted.

FIG. 1 shows the rotor 50. FIG. 1a is a plan view of the rotor 50, and FIG. 1b is a sectional view taken along line AA of FIG.

In the figure, a motor magnet 61 is provided on the lower surface (or the peripheral surface) of the rotor 50 so as to face the drive coil 60. The rotor 50 has a plurality of rows of at least two rows of through holes 50a and 50b for adjusting the dynamic balance which are concentric and have different hole diameters on the outer circumference side and the inner circumference side, respectively, which are located above the motor magnet 61. Provided. The through-holes 50a and 50b are arranged at equal intervals, and 36 are formed at an angle of 10 degrees with the adjacent through-hole.

A row of through holes on the outer peripheral side is formed with a diameter of 1 mm, and a micro ball 1 weighing about 4 mg is provided in the through hole 50a.
00a is inserted. In addition, the through-hole array on the inner peripheral side has a diameter of 0.
A microball 100b having a weight of about 2 mg is inserted into the through hole 50b.

As the microballs 100a and 100b, for example, those for a miniature bearing made of a magnetic material made of an iron member are used. Therefore, the inserted microball is attracted by the magnetic force of the motor magnet 61,
The rotor 50 does not fall off from the casing (case) of the rotor 50 formed with a thickness of about 0.8 mm.

Therefore, as described above, the microball 10
0a and 100b are through holes 50 opened in the rotor case.
The adjustment of the dynamic balance can be performed in a state where it is incorporated in the disk clamp mechanism as a motor for rotational drive only by being inserted into the a and 50b.

The description of the above embodiments is for the purpose of illustrating the present invention and should not be construed as limiting the invention described in the claims or reducing the scope thereof. In addition, the configuration of each part of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[0043]

As described above, according to the present invention, through holes 50a and 50b for adjusting dynamic balance are formed in the rotor 50 at concentric circles and at equal intervals, and the through holes 50a and 50b are located above the motor magnet 61. A plurality of rows were opened with different hole diameters on the outer circumference and the inner circumference. And these through holes 50
Since the microballs 100a and 100b formed with diameters corresponding to the through holes are inserted into the holes 50a and 50b, the dynamic balance can be adjusted with high accuracy.

The micro balls 100a, 100b
Is attracted by the magnetizing force of the motor magnet 61,
For this reason, it is not necessary to use an adhesive for fixing to the through hole, and the dynamic balance can be easily adjusted, which is useful.

[Brief description of the drawings]

1 shows a rotor according to the invention, FIG. 1a being a plan view, FIG.
FIG. 1B is a cross-sectional view taken along the line AA, and FIG. 1B is a view particularly showing the relationship between the through hole and the microball.

FIG. 2 is a side view of a disk recording / reproducing apparatus in which a normal motor is arranged on a pickup side.

FIG. 3 is a sectional view of a conventional clamper and a turntable.

FIG. 4 is a sectional view of a clamper and a turntable in another conventional example.

FIG. 5 is a diagram showing a positional relationship between a clamper and a turntable in a disk insertion standby state in another conventional surface-facing motor.

FIG. 6 is a diagram showing a positional relationship between a clamper and a turntable at the time of recording / reproducing a disk in another conventional surface-facing motor.

FIG. 7 is a diagram showing a positional relationship between a clamper and a turntable in a disk insertion standby state in another conventional circumferentially opposed motor.

FIG. 8 is a diagram showing a positional relationship between a clamper and a turntable at the time of recording / reproducing a disk in another conventional circumferentially opposed motor.

[Explanation of symbols]

 Reference Signs List 50 rotor 50a through hole 50b through hole 61 motor magnet 100a micro ball 100b micro ball

Claims (4)

[Claims] 1. A turntable 7 on which a recording / reproducing disk 4 is rotatably mounted, and the turntable 7
And a clamper 5 that is provided so as to be relatively close to and separated from the turntable, and presses and holds the disk 4 with the turntable 7.
The clamper 5 is a disk clamp mechanism having a motor 6 for rotating a turntable 7, wherein a core core 63 is provided on a support member to which the clamper 5 is attached, and a drive coil wound on the core core 63. 60, a rotor 50 provided in a cylindrical shape with an opening facing the disk 4 side, and a motor magnet 61 formed on a surface of the rotor 50 facing the drive coil 60 to constitute a motor. A disc for an optical disc reproducing apparatus, wherein concentric and equidistant through holes for dynamic balance adjustment are formed, and micro balls of different diameters corresponding to the hole diameters are inserted into the through holes. Clamp mechanism. 2. The disc clamp of an optical disc reproducing apparatus according to claim 1, wherein said through holes are located above said motor magnet, and are provided in a plurality of rows on an outer circumference and an inner circumference. mechanism. 3. The disc clamp mechanism of an optical disc reproducing apparatus, wherein the through hole according to claim 2 is formed to have different hole diameters on an outer periphery and an inner periphery. 4. The disk clamp mechanism of an optical disk reproducing device, wherein the microball according to claim 3 is a magnetic material made of an iron member.