JP2000057727A - Mounting structure of hard disk for magnetic recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the position deviation or damage of a plurality of hard disks (magnetic disks) for magnetic recording without complicating the mounting structure. SOLUTION: In the mounting structure of magnetic disks 5 through a ring- shaped spacer 24 on a hub body 23 connected with a spindle 1, the hub body 23 and the ring-shaped spacer 24 are constituted of materials whose thermal expansion coefficient is substantially equivalent to that of the magnetic disk 5, and a conductive film is formed on at least an exposed part surface in a state of mounting the hub body 23 and the ring-shaped spacer 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk mounting structure in a magnetic recording hard disk (hereinafter, simply referred to as "magnetic disk") device, and more particularly, to a magnetic disk formed of a substrate made of an insulating material and a hub of the magnetic disk device. The present invention relates to a structure attached to a component.

[0002]

2. Description of the Related Art Conventionally, aluminum, glass, ceramics, carbon and the like have been used as a substrate material for a magnetic disk. Currently, aluminum and glass are mainly used depending on the size and application. A plurality of magnetic disks made of these materials are mounted at equal intervals via spacers on a hub component connected to a rotation drive mechanism of the magnetic disk device.

In recent years, as the recording density of a magnetic disk has increased, it has been required to minimize the flying distance between the magnetic head and the magnetic disk, to reduce the thickness of the magnetic recording medium layer of the magnetic disk, and the like. In order to improve impact resistance, a magnetic disk device using a magnetic disk made of glass, crystallized glass, or ceramics substrate having excellent mechanical strength has been proposed.

FIG. 2 is a sectional view of a main part for explaining a mounting structure of a conventional magnetic disk drive. In the figure, 1
Is a spindle connected to the rotary drive mechanism, 2 is a bearing,
Reference numeral 3 denotes a hub body, 4 denotes a ring-shaped spacer, 5 denotes a plurality of magnetic disks, and 6 denotes a fixed disk. The plurality of magnetic disks 5 are inserted into the hub body 3 connected to the spindle 1 via the ring-shaped spacers 4, respectively.
Furthermore, it is fixed at a predetermined interval by being fixed thereon by screws 7 via a fixing disk 6.

[0005]

Conventionally, the hub body and the ring-shaped spacer have been made of metal. For this reason, when glass, crystallized glass or ceramics is used for the substrate, a difference occurs in the coefficient of thermal expansion, which causes a problem. For example, a glass substrate has a thermal expansion coefficient α of 80 × 10 ^−7.
/ ° C., while the coefficient of thermal expansion α of the metal such as the hub body and the ring-shaped spacer is about 230 × 10 ⁻⁷ / ° C., the difference is large. As a result, the magnetic disk may be displaced, and in some cases, an excessive thermal stress may be caused to damage the magnetic disk. In particular, the misalignment of the magnetic disk is caused by a track miss (Track Misregistration).
), which is a major obstacle in increasing the recording density.

In order to eliminate the above drawbacks, α = 80 × 10, which has a thermal expansion coefficient close to that of a glass substrate, such as a ring-shaped spacer.
It has also been proposed to use a material having a temperature of about ⁻⁷ / ° C., for example, an alumina ceramic material. However, since the thermal expansion coefficient of glass, crystallized glass, or ceramics differs depending on the type of substrate, it is difficult to use one spacer material for all types of substrates.

For example, when glass is used, it does not contain alkali which causes disk corrosion.
It is desirable to use alkali-free glass having high durability, but alkali-free glass materials having a high thermal expansion coefficient are limited. For example, alkali-free glass widely used as a substrate for TFT-LCD has a thermal expansion coefficient of 30.
~ 50 × 10 ^-7 / ° C. If these general-purpose materials can be used for the disk substrate, cost reduction due to mass production effect can be expected, but the above-mentioned problem cannot be used because the difference in thermal expansion coefficient between the metal hub body and the ring-shaped spacer is large. .

On the other hand, when a glass, crystallized glass or ceramic material of the same material as the disk substrate is simply used for the ring-shaped spacer or the like, since these are brittle materials, cracks and breakage are liable to occur, and the reliability of the device is high. There is a problem that decreases. In addition, since many of these materials are insulators, static electricity is easily generated when the magnetic disk is driven to rotate, etc., and there is a problem that dust and dirt are attracted to prevent stable recording and reproduction.

[0009]

The object of the present invention is to provide a hub body and a ring-shaped spacer which have substantially the same thermal expansion coefficient as a disk substrate, have sufficient mechanical strength, and have a conductivity which does not easily generate static electricity. It is solved by having.

That is, according to the present invention, in a structure in which a magnetic disk is mounted on a hub main body connected to a spindle via a ring-shaped spacer, the hub main body and the ring-shaped spacer have substantially the same thermal expansion coefficient as the magnetic disk. A magnetic disk mounting structure comprising a material and a conductive film formed on at least a surface of the exposed portion when the hub body and the ring-shaped spacer are mounted.

In the present invention, the magnetic disk preferably has a substrate made of glass, crystallized glass or ceramics. In the present invention, the conductive film is preferably made of SnO ₂ .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment of the present invention, the material of a mounting portion such as a hub body and a ring-shaped spacer for mounting a magnetic disk made of glass, crystallized glass or ceramics is in thermal expansion with the magnetic disk. It is made of a material having substantially the same coefficient, more specifically, a material having a coefficient of thermal expansion in the range of ± 10% of the coefficient of thermal expansion of the magnetic disk in use, and at least the exposed portion when the hub body and the ring-shaped spacer are attached. It is characterized in that a conductive film is formed on the surface.

According to this configuration, it is possible to prevent the magnetic disk from being displaced due to a difference in thermal expansion coefficient and from being damaged due to thermal stress. Also, by forming a conductive film on at least the exposed surface of the hub body and the ring-shaped spacer when the hub body and the ring-shaped spacer are attached, it is possible to prevent the generation of static electricity, prevent dust and dirt from being attracted, and at the same time, prevent scratching and Strength such as impact strength can also be improved.

As the conductive film, a SnO ₂ film, a Sn-doped In ₂ O ₃ film, a Ga-doped ZnO film and the like are used. Among them, the SnO ₂ film has a high surface hardness and a high resistance. It is a particularly preferred material because of its excellent abrasion. The SnO ₂ film may be a SnO ₂ film doped with F or Sb.

The method for forming the conductive film is not particularly limited, and examples thereof include a chemical vapor deposition method and a spray method. Here, the chemical vapor deposition method means that a substance capable of forming a film having a predetermined composition by thermal decomposition, for example, a metal organic compound is heated and vaporized, and this is introduced into a coating chamber with a carrier gas, for example, air, oxygen, and an inert gas. Carrying, on the surface of the hub body and the ring-shaped spacer,
A method of forming a film having a predetermined composition by reacting with oxygen or water in an atmosphere or on the surface of the material.
The spray method is a method in which a raw material is dissolved in an organic solvent, sprayed on the surfaces of the hub body and the ring-shaped spacer and thermally decomposed to form a film on the surface.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an essential part showing an embodiment of a magnetic disk mounting structure according to the present invention. In the figure, the hub body 2
3. The ring-shaped spacer 24 and the fixed disk 26 are made of a magnetic disk 5 made of glass, crystallized glass or ceramics.
Is made of a material having substantially the same thermal expansion coefficient as the above, and the SnO ₂ film 2 is formed on the surface in advance. One or a plurality of glass, crystallized glass or ceramic magnetic disks 5 are mounted on the hub 23 via a ring spacer 24.
Is provided, and the fixed disk 26 is mounted thereon with screws 7 to form a mounting structure. As a result, it is possible to prevent displacement of the magnetic disk due to a difference in thermal expansion coefficient and breakage due to thermal stress.

The distortion caused by the difference in thermal expansion between the fastening screw 7 and each glass, crystallized glass or ceramic member is absorbed by the interposition of the spring washer 27, so that there is no problem such as generation of thermal stress on the magnetic disk 5. .

The SnO ₂ film was formed by spraying SnCl ₄ with the surfaces of the hub body and the ring-shaped spacer raised to several hundred degrees Celsius. Here, the coefficient of thermal expansion α = 85 × 10 ⁻⁷
The surface abrasion when the SnO ₂ film was formed on the surface of the aluminosilicate glass at / ° C was observed and evaluated in comparison with the case where the film was not provided. The evaluation was performed for 10 different sheets.
As a result, as shown in Table 1, the degree of damage was significantly suppressed by the SnO ₂ film.

In the samples with the SnO ₂ film, only slight damage was observed in all of the ten samples, but in the samples without the SnO ₂ film, significant damage was recognized in all of the ten samples.
A remarkable effect by the SnO ₂ film is recognized.

Further, in the configuration of the above embodiment,
Although not shown, a jet port for ejecting an air flow between the magnetic disks from the center of the hub body and a dust removing filter are not shown, but it is preferable to arrange them in order to prevent dust adhesion.

[0021]

[Table 1]

[0022]

According to the present invention, even if a plurality of magnetic disks made of glass, crystallized glass or ceramics are used without complicating the mounting structure, the difference in the thermal expansion coefficient between the mounting structure and the magnetic disk can be reduced. Due to this, it is possible to prevent positional displacement or damage due to thermal stress, and to achieve excellent effects such as not causing mistracking due to positional displacement and remarkably improving the reliability of the magnetic disk drive. Also, due to the conductive film on the surface,
It is possible to prevent generation of static electricity and adsorption of dust and dust, and at the same time, improve scratch resistance and impact resistance.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention.

FIG. 2 is a sectional view of a main part showing a conventional magnetic disk mounting structure.

[Explanation of symbols]

 1: Spindle 2: Bearing 3: Hub body 4: Ring spacer 5: Magnetic disk 6: Fixed disk 7: Screw 23: Hub body 24: Ring spacer 26: Fixed disk 27: Spring washer

Claims (3)

[Claims] In a structure in which a hard disk for magnetic recording is mounted on a hub main body connected to a spindle via a ring-shaped spacer, the hub main body and the ring-shaped spacer have substantially the same thermal expansion coefficient as the hard disk for magnetic recording. A mounting structure for a hard disk for magnetic recording, wherein a conductive film is formed on a surface of at least the exposed portion when the hub body and the ring-shaped spacer are mounted on the hub. 2. The magnetic recording hard disk substrate material is glass, crystallized glass or ceramics.
The mounting structure of the magnetic disk described in the above. 3. The mounting structure for a magnetic recording hard disk according to claim 1, wherein the conductive film is made of SnO ₂ .