JPH07169181A - Disk driving device - Google Patents

Abstract

PURPOSE:To obtain a disk driving device capable of improving accuracy of disk mounting planes in a rotor hub and to increase the recording density of the disk. CONSTITUTION:The ceramic disk supporting plane forming member 20 of a thin plate circular shape is mounted on the upper plane of the ring shaped projecting part 9 of a rotor hub 8 and a disk 16 is mounted on the forming member 20. Moreover, another disk 16 is mounted on the disk 16 through a spacer 21. Projected lines in the circumferential direction are formed projectingly on upper and lower planes of the forming member 20 and the spacer 21 and the working into plane shape for forming mounting plane only for projected lines is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a disk drive device for rotationally driving a recording disk such as a magnetic disk or a magneto-optical disk.

[0002]

2. Description of the Related Art Conventionally, in this type of disk drive device, an annular recess is formed at an appropriate position of a base serving as a fixing member, a boss portion is provided at the center of the annular recess, and a central hole of the boss portion is provided. The fixed shaft is press-fitted and fixed, and the rotor hub is rotatably supported on the fixed shaft thus erected on the base via bearings.

This rotor hub is made of a non-magnetic material such as aluminum. A disk is placed on an annular overhang formed on the outer periphery of the lower part, and is fixed between the disk and a clamp member. The disk can be rotated integrally with the rotor hub by sandwiching. A rotor magnet is mounted on the inner peripheral surface of the annular protrusion of the rotor hub via a yoke.

A short supporting cylinder is provided on the upper surface of the boss portion of the base so that the stator is fitted and fixed to the outer circumference of the supporting cylinder, and the rotor magnet faces the outer circumference of the stator with a slight gap. ing.

An annular wall is provided on the upper surface of the rotor hub in the vicinity of the inner circumference, and a cap for closing the upper surface is fixed to the inner side of the annular wall by, for example, an ultraviolet curing adhesive. The annular lid seal hermetically closes the screw hole in the inner surface of the rotor hub.

[0006]

By the way, in the above-mentioned disk drive device, the rotor hub is made of the same material as the disk or a material having a thermal expansion coefficient close to that of aluminum, stainless steel, etc. I tried to suppress the distortion as much as possible. Since the mounting surface of the annular overhanging portion on which the disk of the rotor hub is mounted is required to have high positional accuracy and surface accuracy, this mounting surface is finished, but a metal material such as aluminum or stainless steel has a Young's modulus of Since it is relatively small, the load applied to the rotor hub during processing causes the rotor hub to be easily distorted, which makes it difficult to obtain the processing accuracy of the annular overhanging portion of the rotor hub, which hinders the improvement of the recording density of the disk mounted on the annular hub. .

The present invention has been made in view of the above problems, and an object of the present invention is to improve the accuracy of the disk mounting surface of the rotor hub and increase the recording density of the disk. Another object of the present invention is to provide a simple disk drive device.

[0008]

In order to achieve the above object, in a disk drive apparatus of the present invention, a fixing member, a rotor hub rotatable with respect to the fixing member, and a disk provided on the outer periphery of the rotor hub. A ring-shaped protrusion of the rotor hub, a stator fixed to the fixing member, and a rotor magnet mounted on the rotor hub and facing the stator with a slight gap therebetween. A thin disk-shaped ceramic disc support surface forming member is placed on the upper surface of the projecting portion, and the disc is placed on the forming member.

[0009]

Since the disk support surface forming member placed on the annular overhanging portion of the rotor hub is made of ceramics having a large Young's modulus, the forming member is not easily distorted by the load at the time of processing, and is highly accurate. A machined surface can be obtained. Therefore, the disk surface can be maintained at a predetermined accuracy without finishing the annular overhanging portion with high accuracy, the occurrence of errors when reading / writing information from the disk is prevented, and the recording density is increased. You can

[0010]

EXAMPLES Examples will be described in detail with reference to FIGS. 1 to 3. FIG. 1 shows a first disk drive device according to the present invention.
2 is a partial sectional view showing the spacer member shown in FIG. 1. FIG.

An annular recess 2 is formed at an appropriate position of a base 1 serving as a fixing member, a boss portion 3 is provided at the center of the annular recess 2, and a fixed shaft 5 is press-fitted and fixed in a central hole 4 of the boss portion 3. The rotor hub 8 is rotatably supported on the fixed shaft 5 via bearings 6.

A short support cylinder 13 is provided on the upper surface of the boss portion 3 of the base 1, and a stator 14 is externally fitted and fixed to the outer circumference of the support cylinder 13. A slight gap is provided on the outer circumference of the stator 14. A rotor magnet 12 fixed to the rotor hub 8 via a yoke 11 faces the rotor hub 8.

An annular wall 15 is provided on the upper surface of the rotor hub 8 so as to protrude toward the inner periphery thereof, and a cap 17 for closing the upper surface is fixed to the inside of the annular wall 15 by, for example, an ultraviolet curable adhesive 18. An annular lid seal 19 hermetically closes the screw hole 10 on the inner surface of the rotor hub 8.

A disk 16 is provided on the outer peripheral portion of the rotor hub 8.
An annular projecting portion 9 for mounting a disc is formed on the annular projecting portion 9, and an annular disc supporting surface forming member 20 having a dimension between upper and lower machining surfaces, that is, a thickness of about 1 mm is laid on the annular projecting portion 9. The disc 16 is placed on the upper surface. Further, another disk 16 is stacked on this disk 16 via a spacer 21. The forming member 20 and the spacer 21 are made of fine ceramics such as silicon carbide or silicon nitride. Since the fine ceramics has a large Young's modulus, it is difficult to be deformed under a load applied during processing, and processing accuracy is easily obtained.

The forming member 20 has an annular shape, and is configured such that the radially inner and outer peripheral sides of the axially upper and lower surfaces are not in contact with the annular protrusion 9 or the disk 16. The spacer 21 has an annular shape, and the disk 1 is located on the radially inner peripheral side of the axial upper and lower surfaces.
It is configured so that it does not touch 6. Portions of the forming member 20 and the spacer 21 that are in contact with the rotor hub 8 or the disk 16 project vertically in the axial direction, and have a tapered diameter in cross section. The forming members 20 and 21 are configured so that only a part thereof is in contact with the rotor hub 8 or the disk 16 in order to reduce the processing area. As a result, the processing time is short and the processing is easy.

A clamp member 7 is mounted on the upper surface of the rotor hub 8, and by screwing a screw into a screw hole 10 provided in the rotor hub 8, the two discs 16 form an annular protrusion 9 and a clamp member 7. It is sandwiched between them and fixed integrally to the rotor hub 8.

FIG. 3 is a partial sectional view showing a second embodiment of the present invention. The disk support surface forming member 22 is annular and is made of fine ceramics similar to that described above. The rotor hub 8 or the disk 16 has a circular cross-section at its contact portion, and the upper and lower portions are cut to be horizontal so that the disk 16 is mounted. It was done like this.

The specific examples of the disk drive device according to the present invention have been described above, but the present invention is not limited to these specific examples, and various modifications and corrections can be made without departing from the scope of the present invention. is there. For example, in the embodiments, the description has been given on the so-called bearing outer ring rotation for fixing the shaft, but it goes without saying that the present invention is applied to shaft rotation, so-called bearing inner ring rotation.

[0019]

Since the present invention is constructed as described above, it has the following effects.

A disk support surface forming member made of ceramics, which has a large Young's modulus and a small strain due to a load during processing and is easy to obtain accuracy, is placed on the annular protrusion of the rotor hub.
Since the disc is mounted on this forming member, the disc can be held with a predetermined precision even if the annular protrusion of the rotor hub has a lower precision than the conventional one. It is possible to increase the read speed and prevent errors during reading / writing.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a disk drive device according to the present invention.

FIG. 2 is a partial cross-sectional view showing the disk support surface forming member of FIG.

FIG. 3 is a partial cross-sectional view of a disk support surface forming member showing a second embodiment of the present invention.

[Explanation of symbols]

 1 Base 5 Shaft 6 Bearing 8 Rotor Hub 12 Rotor Magnet 14 Stator 16 Disc 20 Disc Support Surface Forming Member 21 Spacer

Claims (3)

[Claims] 1. A fixing member, a rotor hub rotatable with respect to the fixing member, an annular overhanging portion provided on an outer periphery of the rotor hub for mounting a disk-shaped disc, and fixed to the fixing member. A disk drive device comprising a stator and a rotor magnet mounted on the rotor hub and opposed to the stator with a slight gap, wherein a thin disk-shaped ceramic disk support is provided on an upper surface of the annular protrusion of the rotor hub. A disk drive device, wherein a surface forming member is placed, and the disk is placed on the forming member. 2. The disk supporting surface forming member has circumferential projections bulgingly formed on the upper and lower surfaces thereof, and a flat surface processing is performed to form a mounting surface only on the projections. 1. The disk drive device according to 1. 3. The disk drive device according to claim 1, wherein a plurality of disks are mounted on the rotor hub, and an annular ceramic spacer is interposed between the disks.