JPH09120655A - Disk-like recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a spring back in a center hub and achieve high accuracy by molding the center hub of a synthetic resin material and arranging a chucking plate of a magnetic metallic material at a bottom face of the center hub. SOLUTION: A magnetic disk 1 is provided with a disc-like disk plate 2, a center hub 3 arranged at a central part of the plate 2, a chucking plate 4 set at a bottom face of the hub 3, and a double-faced adhesive ring 5 for bonding/securing the plate 2 and the hub 3. A circular center hub-supporting hole 9 is formed at the central part of the plate 2. A circular storing/supporting part 10 like a shallow saucer to be accommodated in the supporting hole 9 of the plate 2 and a projecting, ring-shaped flange part 11 in an outer circumference of the supporting part 10 are integrally formed in the hub 3. The hub 3 is formed by injection molding of ABS resin, polyoxymethylene or the like plastic inside a cavity defined between a fixed mold and a moving mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk-shaped recording medium, such as a magnetic disk, an optical disk, a magneto-optical disk, which enables recording of information signals such as data signals and musical sound signals.

[0002]

2. Description of the Related Art Heretofore, there has been proposed a disk-shaped recording medium such as a magnetic disk, an optical disk or a magneto-optical disk in which a desired information signal such as a data signal and a musical tone signal is stored in a cartridge body. This disc-shaped recording medium is capable of high-density recording of information signals and has been proposed to have an extremely small diameter. This type of magnetic disk has a small diameter, for example, 3.5 inches or less.

As described above, a magnetic disk having an extremely small diameter and capable of high density recording is mounted on a disk rotation drive device and rotated at a high speed. Data signals are recorded or read by a magnetic head in contact with a magnetic layer formed on a disc-shaped disk substrate that rotates while the magnetic disk is rotated at a high speed.

By the way, in the magnetic disk, in order to accurately record and reproduce the data signal, the magnetic head needs to contact the accurate position. Therefore, the magnetic disk must be securely mounted on the disk table of the disk rotation drive device, accurately positioned with respect to the disk table, and rotated in synchronization with the disk table. .

Therefore, since the magnetic disk is securely mounted on the disk table and is positioned and mounted on the disk table with high accuracy, the magnetic disk is mounted on the disk table while being mounted on the disk table. It is equipped with a center hub that is magnetically attracted by the magnet.

The center hub is made of a metallic material such as a magnetic material, and is formed in a circular shallow dish shape in which a flange portion projects over the outer peripheral portion. The center hub has a bottom surface accommodated in the center hub support hole, and a flange portion is hooked in the vicinity of the center hub support hole on one main surface side of the disc plate and fixed via a double-sided adhesive ring. Further, the center hub has a center hole penetrating into the spindle shaft erected at the center of the disc table and a positioning hole penetrating into the drive pin erected near the spindle shaft of the disc table. It is provided.

[0007]

By the way, in the above-mentioned conventional magnetic disk, the center hub is formed by pressing a sheet metal of a metal material which is a magnetic material having a thickness of about 0.3 mm. . This center hub is made by punching a metal material plate into a disk shape and then drawing it into a shallow dish shape from a disk-shaped metal material sheet. Formed into a shape. The center hole and the positioning hole are formed in the center hub by punching or the like.

However, since this center hub is made of a metal material, there is a problem that after the sheet metal of the metal material is formed by pressing, elasticity causes springback, which somewhat returns the shape of the flange portion to the original shape. there were. As a means for solving this problem, there has been taken a means of extra bending in consideration of the springback amount. However, this method has a drawback in that it is difficult to accurately estimate the springback amount, and it is necessary to correct it many times by finally performing trial bending. In addition, this method has a drawback in that even if processing is performed under the same conditions with a die that has been modified and determined many times, the springback is greatly affected by the degree of processing of the sheet metal, causing variations in product angle. . Therefore, the conventional center hub has a problem in that the flange portion is distorted or wavy, which makes it difficult to perform high-precision machining.

Further, since the center hub is made of a metal material, it becomes difficult to form the center hole and the positioning hole at a highly accurate position and size corresponding to the spindle shaft and the drive pin. There was a problem that burr occurred.

Further, in the processing step of the center hub, many defective products that do not match the predetermined dimensional accuracy and cannot be remanufactured or reused are produced, resulting in a low yield.
There was a problem that the production efficiency decreased and the production cost increased. The center hub is required to have high precision, especially in height, as the capacity of the magnetic disk increases.

Therefore, the present invention has been proposed for the purpose of providing a disc-shaped recording medium such as a magnetic disk which prevents the occurrence of springback of the center hub and improves the accuracy.

[0012]

A disk-shaped recording medium according to the present invention, which has achieved this object, is a disk having an information signal recording layer such as a magnetic layer formed on at least one main surface of a disk substrate made of a synthetic resin material. It has a plate and a center hub arranged in the center of the disc plate. The center hub is formed by molding a synthetic resin material such as ABS resin or polyoxymethylene, and a chucking plate made of a metal material such as a stainless steel material (SUS-430) that is a magnetic material is disposed on the bottom surface of the center hub. ing.

According to the disk-shaped recording medium of the present invention having the above-mentioned structure, the chucking plate arranged on the bottom surface of the center hub is magnetically attracted by the magnet on the disk rotation driving device side, and the disk table. Is securely attached to. Then, the disc-shaped recording medium is rotated at a high speed by rotationally driving the disc table on the side of the disc rotation drive device, and a desired information signal is recorded or read by the magnetic head.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below in detail with reference to the drawings of FIGS. Magnetic disk 1 shown as an embodiment of the present invention
Although not shown, is rotatably supported by the cartridge body to form a disk cartridge. As shown in FIG. 1, the magnetic disk 1 includes a disk plate 2 formed in a disk shape, a center hub 3 arranged in the center of the disk plate 2, and a bottom surface of the center hub 3. The chucking plate 4 and the double-sided adhesive ring 5 for adhering and fixing the disc plate 2 and the center hub 3 are provided.

The disk plate 2 is formed of a synthetic resin material such as polyester, polycarbonate, polymethylmethacrylate, or polyolefin into a disk shape having a diameter of 3.5 inches, and a disk substrate on which a data signal is recorded, and the disk substrate. And a magnetic layer formed by applying a magnetic paint to both main surfaces of the. As shown in FIG. 1, the disc plate 2 has a circular center hub support hole 9 formed in the center thereof.

As shown in FIG. 2, the center hub 3 has a circular, shallow dish-shaped storage support portion 10 which is stored in the center hub support hole 9 of the disc plate 2, and an outer peripheral edge of the storage support portion 10. A ring-shaped flange portion 11 projecting over the same is integrally formed. As shown in FIG. 3, the center hub 3 is formed by injection-molding a plastic such as ABS resin or polyoxymethylene inside a cavity 22 formed between a fixed mold 20 and a movable mold 21. ing.

The storage support portion 10 has an outer diameter dimension slightly smaller than the inner diameter dimension of the center hub support hole 9 of the disc plate 2. As shown in FIG. 2, the storage support portion 10 is located at the center of the bottom surface of the disk rotation drive device 3.
A substantially rectangular center hole 1 that is inserted into a spindle shaft 33 that is erected at the center of a disk table 31 that constitutes 0.
2 is provided so as to penetrate therethrough. Also, the storage support 10
Is provided in the vicinity of the center hole 12 on the bottom surface and has a substantially vertically elongated rectangular positioning hole 13 penetrating therethrough, which is inserted into the drive pin 34 provided upright in the vicinity of the spindle shaft 33 of the disk table 31. ing. Also, the storage support 10
Is provided with a locking projection 14 standing outward on the outer peripheral edge of the bottom surface.

As shown in FIG. 4, the chucking plate 4 includes a metal plate 18 made of a metallic material such as stainless steel (SUS-430) which is a magnetic material between the punch 23 and the die 24.
The sheet metal 18 is punched out with the interposition of, to form a disk shape. As shown in FIG. 2, the chucking plate 4 is provided with a substantially rectangular center hole 15 penetrating therethrough at a position corresponding to the center hole 12 of the center hub 3, and at a position corresponding to the positioning hole 13 of the center hub 3. A substantially vertically elongated rectangular positioning hole 16 is provided therethrough. Further, the chucking plate 4 is provided with a locking hole 17 through which the locking protrusion 14 of the center hub 3 is inserted.

Therefore, in the center hub 3, as shown in FIG. 5, the locking projection 14 is projected from the locking hole 17 of the chucking plate 4, and the projecting portion of the locking projection 14 is caulked. As a result, the chucking plate 4 is securely fixed to the bottom surface of the storage support portion 10.

As shown in FIG. 6, in the center hub 3, the storage support 10 to which the chucking plate 4 is fixed is stored in the center hub support hole 9 of the disc plate 2, and the flange 11 is attached to the double-sided adhesive ring 5. By being adhered to the vicinity of the center hub support hole 9 of the disc plate 2 via, it is securely fixed to the disc plate 2.

As shown in FIG. 7, the magnetic disk 1 of the embodiment configured as described above has the chucking plate 4 fixed to the bottom surface of the storage support portion 10 of the center hub 3.
Is magnetically attracted by the magnet 32 arranged around the spindle shaft 33 on the side of the disk rotation driving device 30, and is securely mounted on the disk table 31. Also,
In the magnetic disk 1, the center holes 12 and 15 provided in the center hub 3 and the chucking plate 4 are inserted by the spindle shaft 33 on the disk rotation driving device 30 side, and the center of rotation is accurately positioned. Further, the magnetic disk 1 has positioning holes 13 and 16 provided in the center hub 3 and the chucking plate 4,
The drive pin 34 on the side of the disk rotation drive device 30 is inserted, and the positioning in the rotation direction is accurately performed.

The magnetic disk 1 is rotated at a high speed by rotating the disk table 31 on the disk rotation drive device 30 side. Magnetic disk 1
In the state of being operated to rotate at a high speed, a magnetic head in contact with a magnetic layer on a disk substrate rotating and running reliably records or reads a data signal. The magnetic head of the magnetic disk 1 is switched and moved in the tracking direction and selectively scanned to record or read a data signal.

According to the magnetic disk 1 of the above-described embodiment, as described above, the center hub 3 is made of a synthetic resin material, and the bottom surface of the center hub 3 is a disk-shaped chucking made of a magnetic metal material. By disposing the plate 4, the springback of the center hub 3 is prevented from occurring and the accuracy is improved. Therefore, the magnetic disk 1 can be increased in capacity, and the center hub 3 can be reproduced and reused.

Therefore, in the magnetic disk 1, the center hub 3 is formed by injection-molding a synthetic resin material, and the disk-shaped chucking plate 4 is formed by punching out a metal plate 18 made of a magnetic material. Since it is formed, high-precision machining of the center hub 3 can be facilitated, production efficiency can be improved, and production cost can be reduced.

Further, in the magnetic disk 1, since the chucking plate 4 is made of a metal material which is a magnetic material, it is magnetically attracted by the magnet 32 arranged on the disk table 31 on the disk rotation driving device 30 side. The disc table 31 is securely attached to the disc table 31, and abrasion or the like due to the disc table 31 is prevented.

Further, in this magnetic disk 1, since the center hole 12 and the positioning hole 13 of the center hub 3 are made of a synthetic resin material, it is possible to improve the accuracy of the center hole 12 and the positioning hole 13 of the center hub 3. And the occurrence of burrs is prevented. Therefore, the magnetic disk 1 can be positioned accurately with respect to the disk table 31.

Further, the magnetic disk 1 can be applied to the production line which has been conventionally used, since the center hub 3 is adhesively fixed to the disk plate 2 via the double-sided adhesive ring 5 as in the conventional case. To be done.

The present invention can be applied to a disk-shaped recording medium such as an optical disk and a magneto-optical disk, a disk-shaped recording medium that does not require a cartridge, etc., in addition to the magnetic disk 1 of the above-described embodiment.

[0029]

As described above, according to the disk-shaped recording medium of the present invention, the center hub is formed of the synthetic resin material, and the chucking plate made of the magnetic metal material is arranged on the bottom surface of the center hub. By being set up,
The springback of the center hub is prevented from occurring and high accuracy is achieved. Therefore, the disc-shaped recording medium can have a high capacity, and the center hub can be reproduced and reused. Therefore, with this disc-shaped recording medium, it is possible to facilitate high-precision machining of the center hub, improve production efficiency, and reduce production costs.

Further, since the chucking plate of this disk-shaped recording medium is made of a magnetic metal material, it is magnetically attracted to the disk table by a magnet provided on the disk table on the disk rotation drive side. The mounting is ensured, the positioning with respect to the disc table is accurate, and abrasion due to the disc table is prevented.

Further, this disk-shaped recording medium can be adapted to a conventionally used production line by fixing the center hub to the disk plate via the double-sided adhesive ring as in the conventional case.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a disc-shaped recording medium according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a center hub and a chucking plate which form the disc-shaped recording medium.

FIG. 3 is a cross-sectional view showing a fixed mold and a movable mold that form a center hub.

FIG. 4 is a cross-sectional view showing a punch and a die forming a chucking plate.

FIG. 5 is a perspective view of the center hub with the chucking plate fixed, seen from the bottom surface side.

FIG. 6 is a perspective view showing the disc-shaped recording medium.

FIG. 7 is a cross-sectional view showing the disc-shaped recording medium mounted on a disc rotating device.

[Explanation of symbols]

 1 disk-shaped recording medium 2 disk plate 3 center hub 4 chucking plate

Claims (3)

[Claims] 1. A disc hub having an information signal recording layer formed on at least one main surface of a disc substrate made of a synthetic resin material, and a center hub arranged at the center of the disc plate. A disk-shaped recording medium, characterized in that a chucking plate made of a synthetic resin material and having a magnetic material of a metallic material is disposed on the bottom surface. 2. The center hub integrally includes a circular, substantially shallow dish-shaped storage support portion and a ring-shaped flange portion projecting over the outer peripheral edge of the storage support portion, and the chucking plate is a disk. The disk-shaped recording medium according to claim 1, wherein the disk-shaped recording medium is formed in a disk shape. 3. The center hub and the chucking plate are provided with a center hole penetrating therethrough, into which a spindle shaft of the disk rotation driving device enters, and located near the center hole. The disk-shaped recording medium according to claim 1, wherein a positioning hole into which a drive pin on the side of the rotation drive device is inserted is provided.