JP3080320B2 - Hub for optical disc - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk hub mounted at the center of an optical disk, and more particularly to an improvement of a magnetic chucking type optical disk hub.

[0002]

2. Description of the Related Art Conventionally, various optical disks such as a magneto-optical disk have been known as information signal recording media. These optical discs have a number of excellent features, such as high non-contact recording, long-term reliability of recording signals, and large capacity.

In a recording / reproducing apparatus for recording or reproducing data on or from the optical disk, the optical disk is rotated at an extremely high speed of several hundred revolutions per minute or more, and a laser beam is applied to a signal recording surface of the optical disk. Thus, a writing or reading operation of the information signal is performed. Therefore, the recording / reproducing apparatus is provided with some kind of clamp means for integrally coupling the optical disk to the disk table in order to guarantee the accurate rotation of the optical disk.

As an example of such a clamping means, a so-called magnet clamp system has been proposed. Hereinafter, this magnet clamp system will be briefly described.

In the magnet clamp system, a magnet is provided on the disk table side, and a disk hub having a magnetic plate made of a magnetic material as a magnetic attraction plate is attached to the center of the optical disk side. The optical disk is integrally held on the disk table by magnetic attraction. The disk hub is formed, for example, by integrally forming a ring-shaped member made of synthetic resin on a disk-shaped metal plate, and attached to the substrate surface of the optical disk by, for example, ultrasonic welding. is there. In the center of the disc-shaped metal plate, a spindle engaging hole is formed for engaging the center spindle of the disk table, and the optical disc is positioned by the engagement between the center spindle and the spindle engaging hole.

[0006]

In the above-described magnet clamp system, as described above, the center spindle is fitted into the spindle engaging hole of the disk hub when chucking the disk table. At this time, fine metal powder may be generated due to wear of the metal plate or the center spindle, and may adhere to a spindle engaging hole or the like of the metal plate. The difference between the outer diameter of the center spindle and the inner diameter of the spindle engaging hole of the disk hub is extremely small (about 12 μm). Therefore, such adhesion of the metal powder may hinder normal chucking operation. Causes various inconveniences.

For example, in a recording / reproducing apparatus designed so that the center spindle starts rotating simultaneously with chucking of the optical disk, the optical disk is automatically rotated even if the chucking state is incomplete to some extent. . Then, both the disk hub and the center spindle are damaged. Damage to the disk hub or center spindle may cause damage to other optical disks or recording / reproducing devices. If left untouched, damage may be spread one after another.

In order to prevent the damage, there are conceivable methods of improving the metal hardness of the metal plate constituting the disk hub, or applying nickel plating, nickel plating + chrome plating to the metal plate. However, in the method of improving the sheet metal hardness of the metal sheet itself, it is difficult to dramatically improve the durability, and further, the workability of the sheet metal is deteriorated. Further, in the method using nickel plating or nickel plating + chromium plating, it is difficult to maintain the hole diameter accuracy of the spindle engagement hole, and particularly when nickel plating is employed, corrosion or the like also becomes a problem.

Accordingly, the present invention has been proposed in view of such a conventional situation, and provides an optical disk hub which is less damaged by chucking of a center spindle and can maintain a stable chucking state. The purpose is to do.

[0010]

In order to achieve the above-mentioned object, an optical disk hub according to the present invention comprises a ring-shaped member made of a synthetic resin having the same quality as a disk substrate, and an outer ring having a diameter larger than the outer diameter of the ring-shaped member. A metal plate for a magnet clamp which has a diameter and has a stepped portion forming a connecting portion with the ring-shaped member and which is integrally attached to the ring-shaped member, and the surface of the metal plate for the magnet clamp is formed by sputtering. It is characterized by being subjected to a ceramic coating treatment.

[0011]

The coating made of ceramic has a very high hardness and is excellent in wear resistance, corrosion resistance and the like. Therefore, by applying such a ceramic coating process to the metal plate, damage due to chucking of the center spindle is greatly suppressed. Further, since the ceramic coating process is performed by a technique such as ion plating, the accuracy of film thickness control is high, and the accuracy of the diameter of the spindle engagement hole is maintained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described below with reference to the drawings. First, the configuration of the optical disk hub will be described. As shown in FIGS. 1 to 3, the optical disk hub 1 of the present embodiment includes a metal plate 2 magnetically attracted to a magnet provided on a disk table of a disk rotation driving device. And a ring-shaped member 3 for attaching the metal plate 2 to the disk substrate. The metal plate 2 is formed by punching a thin metal plate made of a magnetic material into a disk shape, and has a circular spindle hole 4 in the center of which is engaged with a center spindle of a disk rotation driving device. Has been established. In addition, this metal plate 2
An annular stepped portion 5 formed in a half-punched state by, for example, stepping is provided concentrically with the spindle hole 4 on the outer peripheral side of the ring-shaped member 3.
A plurality of resin insertion holes 6 are formed in the step portion 5 at equal intervals so as to integrate the metal plate 2 with the metal plate 2 by molding. In the metal plate 2, when an optical disk on which the optical disk hub 1 having the metal plate 2 is mounted is mounted on a disk table, the magnets arranged on the disk table are equally attracted at regular intervals without bias. The main surface 2a facing the disk table is a highly accurate flat surface so as to be sucked with force.

On the other hand, a ring-shaped member 3, which is another main member which is integrated with the metal plate 2 and constitutes the optical disk hub 1, suppresses distortion during welding to the disk substrate and also has a disk substrate surface. In order to attach the disc substrate firmly, a synthetic resin of the same quality as the disc substrate is molded. The ring-shaped member 3 is provided on the metal plate 2.
Of the metal plate 2
An inner peripheral side portion 7 supporting the lower surface of the metal plate 2 and an outer peripheral side portion 8 filled in the step portion 5 of the metal plate 2 so as to be substantially flush with the main surface 2a. The peripheral side portion 7 and the outer peripheral side portion 8 are integrally connected via a connecting portion 9 filled in a plurality of resin insertion holes 6 provided in the metal plate 2. Here, a welding rib 10 having a substantially triangular cross section is provided in a substantially central portion of the bottom surface of the inner peripheral side portion 7 according to the shape of the inner peripheral side portion 7, and a wall surface on the inner peripheral side thereof is provided. Reinforcing ribs 11 extending from the metal plate 2 toward the spindle hole 4 of the metal plate 2
Is provided. The welding rib 10 is provided for attaching the optical disk hub 1 to a disk substrate, and the inner peripheral side portion 7 and the disk substrate are separated by applying ultrasonic waves to melt the welding rib 10. Welded. Further, a plurality of the reinforcing ribs 11 are provided on the inner peripheral side portion 7 at equal angular intervals (in this example, at 60 ° intervals),
A projection 11a protruding toward the disk substrate surface is provided at the tip. The distance r from the center of the arc drawn by the inner peripheral side portion 7, that is, the center of the hub 1 to the outer peripheral surface 11b of the protrusion 11a provided on each of the reinforcing ribs 11 is a center formed on the disk substrate. It is set so as to be equal to the inner diameter of the hole, and when the optical disk hub 1 is mounted on the disk substrate, the protrusion 11a is inserted into the center hole for positioning.

The configuration of the optical disk hub 1 is as described above. In the optical disk hub 1 of the present embodiment, the metal plate 2 provided with the spindle engaging hole 4 into which the center spindle is fitted is provided. Ceramic coating treatment is applied. The above ceramic coating process,
This is a technique for forming a ceramic coating thin film having high hardness and excellent wear resistance on the surface of the metal plate 2. By performing such a process, the durability of the metal plate 2 is greatly improved.
As the ceramic coating thin film applied by the ceramic coating treatment, any one having high hardness and high wear resistance may be used. For example, TiN, TiC, a solid solution of TiC and TiN, TiAlN, TiAl ₆ V ₄ CN, TiAl ₆ V ₄
N, Al ₂ O _{3 and the} like. Among them, a Ti-based coating film is preferable, and TiAlN or the like is particularly preferable. Although the film thickness is arbitrary, it is usually selected to be about several μm.

The ceramic coating treatment is performed by heating
It is performed by a method such as the VD method, ion plating, and sputtering. In particular, by employing reactive sputtering, a composite metal-based ceramic thin film such as TiAlN can be formed. This reactive sputtering is performed by, for example, a sputter ion plating apparatus or the like, and is a technique that improves high-speed magnetron sputtering. In a sputter ion plating apparatus, two cathodes (targets) are arranged to face each other, and a coating process is performed by placing a metal plate 2 on an overlapping portion of plasma generated from both cathodes.

As shown in FIG. 4, the optical disk 21 to which the optical disk hub 1 having the above-described configuration is mounted is inserted into the spindle engaging hole 4 of the metal plate 2 constituting the optical disk hub 1 by the disk rotation drive. A center spindle 23 that rotates integrally with the table 22 is inserted and fitted and mounted on the disk table 22. At this time,
The disk table 22 is provided with magnets 24 facing the metal plate 2 at a position corresponding to the metal plate 2 of the optical disk hub 1 with a slight gap between the metal plate 2 and the magnet 24. The chucking state is stabilized by the magnetic attraction force. The optical disk 21
When mounting the optical disk on the disk table 22, first, the center spindle 23 is inserted and fitted into the spindle engaging hole 4 provided on the metal plate 2 of the optical disk hub 1, but the metal plate 2 is subjected to ceramic coating. Therefore, surface rotation and powder drop due to abrasion do not occur, and normal rotation is possible. Therefore, a stable chucking operation can always be maintained without damaging the disk hub or the center spindle.

Although the present invention has been described with reference to specific embodiments, the present invention is not limited to these embodiments.

[0018]

As is clear from the above description, in the optical disk hub of the present invention, since the metal plate which engages with the center spindle of the disk drive is subjected to ceramic coating, the chucking durability is improved. The performance can be greatly improved, and a stable chucking operation can always be maintained. In addition, since the ceramic coating thin film formed by the ceramic coating process has a very thin film thickness and easy control of the film thickness accuracy, it is possible to maintain the hole diameter accuracy of the spindle hole provided in the metal plate, It does not cause corrosion or deterioration of sheet metal workability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one configuration example of an optical disk hub to which the present invention is applied.

FIG. 2 is a plan view showing a configuration example of an optical disk hub to which the present invention is applied.

FIG. 3 is a bottom view showing a configuration example of an optical disk hub to which the present invention is applied.

FIG. 4 is a schematic cross-sectional view of a main part showing a state where an optical disk is mounted on a disk table.

[Description of Signs] 1 ・ ・ ・ Hub for optical disk 2 ・ ・ ・ Metal plate 3 ・ ・ ・ Ring-shaped member 4 ・ ・ ・ Spindle hole

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 1-227280 (JP, A) JP-A 64-7391 (JP, A) JP-A 1-127122 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G11B 23/00 G11B 7/24

Claims (2)

(57) [Claims] 1. A ring-shaped member made of synthetic resin of the same quality as a disk substrate, and a step portion having an outer diameter larger than the outer diameter of the ring-shaped member and forming a connecting portion with the ring-shaped member.
A hub for an optical disc, comprising a metal plate for a magnet clamp integrally attached to a ring-shaped member , wherein the surface of the metal plate for the magnet clamp is subjected to ceramic coating using sputtering. 2. A plurality of resin insertion holes are formed in the step portion of the metal plate, and the resin insertion hole is filled with a resin constituting the ring-shaped member, and the metal plate and the ring-shaped member are connected. The optical disk hub according to claim 1, wherein