JPH05234300A - Magnetic member for magnetic chucking of disk - Google Patents

Abstract

PURPOSE:To prevent the overlap of magnetic plates on each other when the many magnetic plates are aggregated by setting the diameter on the outer peripheral edge side of a main surface part larger than the diameter on the inner peripheral side of a rising peripheral wall part. CONSTITUTION:This magnetic member 21 is formed to a height H1 at which the front end of the main surface part 22 does not project from a recessed part 11 when the member is disposed in a magnetic member housing recessed part 11 of a disk substrate 2. The diameter R3 of the bent part 22a on the outer peripheral edge side of the main surface part 22 where the rising peripheral edge part 23 is bent is formed larger than the diameter R4 on the inner peripheral side of the opening end 23a of the peripheral edge part 23. As a result, the member 21 are prevented from being fitted to each other and can be held separate even if the many members are stacked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic member for magnet chucking used for an information signal recording disk such as an optical disk or a magneto-optical disk for recording a desired information signal.

[0002]

2. Description of the Related Art Conventionally, discs for recording information signals, such as optical discs and magneto-optical discs, on which desired information signals are recorded have been proposed. This type of disc is capable of high density recording of information signals, so that a disc having an extremely small diameter has been proposed. For example, there has been proposed an optical disk or magneto-optical disk having a diameter of about 64 mm and capable of recording a music signal for about 74 minutes.

The magneto-optical disk having such a small diameter and capable of high-density recording of information signals is mounted on a disk rotation driving device and rotated at a high speed. Then, while being driven to rotate at a high speed, a fine recording track provided on a signal recording layer formed on one main surface of the magneto-optical disk is irradiated with a light beam emitted from an optical pickup and a magnetic field head. A desired information signal is recorded by applying an external magnetic field that is magnetic field modulated according to the information signal to be recorded from an external magnetic field generator such as.

In order to accurately irradiate a fine recording track with a light beam while being rotationally driven at such a high speed,
The magneto-optical disk is required to be securely integrated with the disk table of the disk rotation driving device and to be mounted with the rotation center being accurately positioned with respect to the axis of the disk table.

In addition, as described above, high density recording of information signals is possible, and a recording and / or reproducing apparatus using an optical disk such as a magneto-optical disk having a small diameter as a recording medium is also required to be downsized. is there.

Therefore, such a small-diameter optical disc is surely integrated with the disc table to be positioned and mounted with high precision, and a recording and / or reproducing apparatus for recording and / or reproducing an information signal on the optical disc. In order to achieve miniaturization, a magnetic member for magnetic attraction made of a metal plate material or the like that is a magnetic material is disposed on the optical disc side, and this magnetic member is attracted by a magnet disposed on the disc table side, and the optical disc is loaded. A disk mounting method has been proposed which employs a so-called magnet chucking method in which chucking is performed on a disk table.

As shown in FIG. 4, an optical disc 1 used in a magnet chucking system utilizing the attractive force of this magnet is a disc substrate formed by molding a synthetic resin material such as transparent polycarbonate resin into a disc shape. Two
Is equipped with. An information signal recording layer on which a desired information signal is recorded is adhered to one main surface 2a side of the disc substrate 2. In this disc substrate 2, one main surface 2a on which an information signal recording layer is formed is opposite to the other main surface 2b which serves as an information signal writing / reading surface, and an optical signal is read from the writing / reading surface side to the signal recording layer. By irradiating the beam, a desired information signal is recorded or reproduced.

As shown in FIG. 4, a center hole 3 is formed in the central portion of the disc substrate 2 so that a centering member provided on the disc rotation drive side can engage with the center hole 3. Further, a magnetic member 4 for magnet chucking is arranged in the central portion of the one main surface 2a side of the disk substrate 2 so as to close the center hole 3. The magnetic member 4 is formed by punching and bending a metal plate material that is a magnetic body.

On the other side of the main surface 2b of the disk substrate 2 which faces the side on which the magnetic member 4 is arranged, there is provided a ring-shaped protruding portion 6 having a smooth mounting reference surface 5 formed on its tip end surface. It is provided so as to surround the center hole 3.

As shown in FIG. 5, the optical disc 1 thus constructed is positioned and mounted on the disc table 8 of the disc rotation drive mechanism 7 arranged on the recording and / or reproducing device side. That is, the optical disc 1
The centering member 9 disposed on the disc table 8 side is engaged with the center hole 3, and the mounting reference surface 5 of the tip end surface of the protrusion 6 is supported by the disc supporting surface 8a of the disc table 8 on the disc table 8. Be attached to. At this time, the magnetic member 4 of the optical disc 1 is attracted by the magnet 10 arranged on the disc table 8 side, so that the center of the optical disc 1 coincides with the rotation center of the disc table 8 and the mounting position is surely positioned. It is integrated and mounted on the disc table 8.

By the way, the optical disc 1 of this type is designed to prevent fingerprints and dust from adhering to the signal recording portion.
It is stored in a disc cartridge. In the case of the disc cartridge that accommodates the small-sized optical disc 1, the optical disc 2 that is accommodated in order to reduce the size of the recording and / or reproducing apparatus and ensure the ease of handling.
It is desirable to be as thin and small as possible corresponding to 1.

In order to make the disc cartridge thin and compact as described above, it is desirable that the optical disc 1 housed therein also be constructed within the range of the thickness of the disc substrate 2.
Therefore, in order to achieve a thin optical disc 1, as shown in FIGS. 4 and 5, one main surface 2a of the disc substrate 2 is used.
A magnetic member storage recess 11 is formed so as to surround the center hole 3 on the side, and the magnetic member 4 for magnet chucking is disposed so as to be embedded in the metal plate storage recess 11.

However, when the magnetic member 4 is arranged so as to be embedded in the disk substrate 2, the distance from the mounting reference surface 5 at the tip end surface of the protruding portion 6 to the magnetic member 4 becomes small, and the magnetic member 4 is arranged on the disk table 8 side. The amount of engagement of the centering member 9 with respect to the disc substrate 2 becomes small. When the engagement amount of the centering member 9 with respect to the disc substrate 2 becomes small in this way, the disc table 8 of the optical disc 1 is formed.
There is a possibility that accurate centering for the may not be achieved.

Therefore, in order to secure the engagement amount of the centering member 9 for centering the optical disk 1 while achieving the thinning of the optical disk 1, the magnetic member 4 housed in the magnetic member housing recess 11 is arranged. Are formed as shown in FIG. That is, as shown in FIG. 6, the magnetic member 4 has the main surface portion 1 attracted by the magnet 10.
A rising peripheral wall portion 13 that secures a height is bent and formed on the outer peripheral edge side of 2, and a mounting piece portion 14 to the magnetic member storage recess 11 is bent and formed on the free end side of the rising peripheral portion 13. It is a thing. The magnetic member 4 thus formed is centered by the height of the rising peripheral wall portion 13 by mounting the mounting piece portion 14 on the bottom surface 11a of the magnetic member housing recess 11 and disposing the magnetic member 4 on the disk substrate 2. The amount of engagement of the member 9 can be increased, and accurate centering of the optical disk 1 with respect to the disk table 8 can be realized.

[0015]

By the way, as shown in FIG. 6, the magnetic member 4 for magnet chucking conventionally proposed is folded so that the rising peripheral wall portion 13 expands in diameter toward the free end side. It is formed by bending. The diameter R ₁ on the outer peripheral side of the bent portion on the outer peripheral edge side of the main surface portion 12 on which the rising peripheral wall portion 13 is bent is compared with the diameter R ₂ on the inner peripheral side on the free end side of the rising peripheral wall portion 13. It is formed small.
Therefore, when a large number of metal plate materials are assembled after being punched and bent, they are overlapped with each other as shown in FIG. 7 and are not easily separated from each other.

When a large number of magnetic members 4 are overlapped with each other in this way, when the metal plate material is punched and bent and then barrel polishing is performed to remove punching burrs and the like generated during processing, the magnetic members 4 that are overlapped with each other are punched. No sufficient polishing can be performed, and it becomes impossible to obtain a wafer having desired dimensional accuracy.

When the optical member 1 is constructed by attaching the magnetic member 4 with the punching burrs remaining on the disc substrate 2, the punching burs scrape off the disc substrate 2 and the disc cartridge storing the optical disc 1 to produce shavings. Will be generated. The shavings adhere to the signal recording portion of the optical disc 1 and cause a writing or reading error of the information signal.

Further, if a large number of magnetic members 4 are overlapped with each other so as to be fitted to each other, it is necessary to separate them from each other when they are mounted on the disk substrate 2, and unnecessary work is required during the mounting work. Furthermore, not only the individual members of the magnetic member 4 cannot be held by the automatic assembly machine, but also the automatic conveyance is hindered.

Therefore, according to the present invention, even when a large number of magnetic members are assembled as magnetic members formed in a substantially cap shape by forming a rising peripheral wall portion which secures a height on the outer peripheral edge side of the main surface portion, It is proposed for the purpose of solving the above-mentioned problems by making it possible to prevent overlapping with each other.

[0020]

In the magnetic member for magnetic chucking of a disk according to the present invention, a rising peripheral wall portion is bent and formed on the outer peripheral edge side of the main surface portion, and mounted on the free end side of the rising peripheral wall portion. The plate part is bent and formed,
The outer peripheral edge side diameter of the main surface portion is made larger than the inner peripheral side diameter of the rising peripheral wall portion.

[0021]

In the magnetic chucking magnetic member of the disk according to the present invention, the diameter of the outer peripheral edge side of the main surface portion is made larger than the diameter of the inner peripheral side portion of the rising peripheral wall portion, so that they are prevented from overlapping each other.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. The magnetic member 21 for magnet chucking according to the present invention is applied to a disk mounted on a disk table of a disk rotation drive mechanism by a magnet chucking method, and has information configured as described above, for example. The present invention is applied to an optical disc 1 used as a signal recording medium, and is provided in a magnetic member accommodating recess 11 formed by surrounding a center hole 3 on one main surface 2a side of a disc substrate 2 constituting the optical disc 1. It is arranged so as to be buried.

The magnetic member 21 according to the present invention is formed by punching and bending a metal plate material which is a magnetic body. Specifically, magnetic stainless steel (SUS43
0) It is formed by using a plate material.

The magnetic member 21 is raised to the outer peripheral edge side of the main surface portion 22 serving as the attraction surface of the magnet 10 arranged on the disk table 8 side of the disk rotation driving mechanism 7 configured as shown in FIG. Rising peripheral wall 2 that secures the height
3 is formed by bending, and a mounting piece portion 24 on the magnetic member accommodating concave portion 11 is formed by bending on the free end side of the rising peripheral wall portion 23 so as to form a substantially cap shape. Further, at the center of the main surface portion 22, there is provided a through hole 25 used for enabling the component gripping portion of the automatic assembling machine to grip it.

The above-mentioned magnetic member 21 is the magnetic member storage recess 1 of the disk substrate 2 constructed as shown in FIG.
1, the front end of the main surface portion 22 is formed at a height H ₁ that does not project from the magnetic member accommodating recess 11 so as not to increase the thickness of the disk substrate 2. Therefore,
The rising peripheral wall portion 23 is bent so that the magnetic member 21 has the height H ₁ as described above.

The magnetic member 21 having such a structure is
As shown in FIG. 2, the outer peripheral diameter R of the bent portion 22a on the outer peripheral edge side of the main surface portion 22 where the rising peripheral wall portion 23 is bent.
₃ is the open end 2 which is the free end side of the rising peripheral wall portion 23.
The diameter is larger than the inner peripheral diameter R ₄ of the 3a side.

A large number of the magnetic members 21 formed in this way are gathered, and the main surface portion 22 side of one magnetic member 21 is open end 23 of the rising peripheral wall portion 23 of the other magnetic member 21.
Even if they are stacked so as to face the a side, as shown in FIG. 3, the main surface portion 22 side having a large diameter is brought into contact with the mounting piece portion 24 and fitted to the opening end 23a side of the rising peripheral wall portion 23. Is prevented. Therefore, even if a large number of the magnetic members 21 are assembled, the magnetic members 21 are restricted from overlapping each other so as to fit with each other.

[0028]

As described above, even if a large number of magnetic members according to the present invention are assembled, the magnetic members are restricted from overlapping with each other so that they can be fitted with each other, so that they can be reliably separated from each other. Therefore, polishing such as barrel polishing for removing punching burrs generated during punching bending can be reliably performed for each individual magnetic member, and the surface is smooth and the dimensional accuracy is extremely high.

Further, since it becomes possible to surely polish each magnetic member, there is no generation of shavings when it is mounted on a disk substrate and then housed in a disk cartridge, so that information signals can be written or written. It is possible to construct a disk that does not cause a read error.

Furthermore, the work of separating from each other at the time of mounting on the disk substrate is not required, the mounting work process can be simplified, and moreover, the individual assuring by the automatic assembly machine can be realized, so that the mounting work on the disk substrate is extremely easy. Becomes

[Brief description of drawings]

FIG. 1 is a perspective view showing a magnetic member for magnet chucking according to the present invention.

FIG. 2 is a cross-sectional view of the magnetic member.

FIG. 3 is a cross-sectional view showing a state in which a large number of the magnetic members are stacked.

FIG. 4 is a partially cutaway perspective view showing an optical disc to which the present invention is applied.

FIG. 5 is a cross-sectional view showing a state in which the optical disc is mounted on a disc rotation drive mechanism.

FIG. 6 is a cross-sectional view showing a conventional magnetic member for magnet chucking.

FIG. 7 is a cross-sectional view showing a state in which a plurality of conventional magnetic members for magnet chucking are stacked.

[Explanation of symbols]

 21 magnetic member 22 main surface portion 23 rising peripheral wall portion 24 mounting piece portion

Claims (1)

[Claims] 1. A rising peripheral wall portion is bent and formed on the outer peripheral edge side of the main surface portion, and a mounting piece portion is bent and formed on the free end side of the rising peripheral wall portion. A magnetic member for magnetic chucking of a disk, the diameter of which is larger than the diameter of the rising peripheral wall portion on the inner peripheral side.