JPH0660513A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent the deformation of a magnetic disk, such as distortion of its inner circumferential part and waviness, etc., by clamping a magnetic disk in press-fitting a protrusion on the uppermost part of a rotary hub into a thin annular clamp member in a state of placing the disk on the rotary hub. CONSTITUTION:The magnetic disks 8a-8c are supported via spacers 9a-9c by the rotary hub 4, and the inner circumferential part of the upper surface of the disk 8c is pressed by a clamper 21. At this time, the clamper 21 is elastically deformed in a concentric pattern by press-fitting the protrusion part 24 of the hub 4 into an inner diameter of the clamper 21, and the disk 8c is pressed by this reaction force with an outer diameter part. Consequently, the deformation of the clamper 21 becomes even in the concentric pattern, and the clamping can be performed by reducing distortion and waviness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device used for reading and writing information.

[0002]

2. Description of the Related Art In recent years, magnetic disk devices have become smaller, thinner, and have a larger capacity as OA equipment has become smaller.

The structure of a conventional magnetic disk device is shown in FIG. Reference numeral 1 is a shroud for fixing the mechanical portion of the magnetic disk device and protecting it from dust in the atmosphere, 2 is a spindle motor base fixed in the shroud, 3 is a bearing held by the spindle motor base 2, 4 Is a rotatable rotary hub integrally configured with the rotary shaft,
It is supported by the spindle motor base 2 via a bearing 3. Reference numeral 5 is a stator core mounted on the spindle motor base 2, 6 is a stator winding wound around the stator core 5, and 7 is a permanent magnet mounted on the rotary hub 4 so as to face the stator core 5. 8 is a magnetic disk for recording information, 9 is a spacer to be inserted between the magnetic disks, 10 is a disk-shaped clamper for mounting the magnetic disk 8 and the spacer 9 on the rotary hub 4, and 11 is a fastening between the clamper 10 and the rotary hub 4. It is a screw for doing. When the magnetic disk 8 and the spacer 9 are mounted and attached, the magnetic disk 8a has its lower surface inner peripheral portion supported by the large diameter portion of the bottom of the rotary hub 4 and its upper surface inner peripheral portion pressed by the lower surface of the spacer 9a.
The magnetic disk 8b is supported by the upper surface of the spacer 9a on the inner peripheral surface of the lower surface and is pressed by the lower surface of the spacer 9b. The magnetic disk 8c at the uppermost stage is supported by the spacer 9b at the inner peripheral portion of the lower surface, and is pressed by the clamper 10 at the inner peripheral portion of the upper surface. The pressing of the clamper 10 against the magnetic disk 8c is caused by fastening the clamper 10 and the upper end of the rotary hub 4 with the screw 11.
This is due to elastic deformation of 0.

Reference numeral 12 is a magnetic head that floats above the magnetic disk 8 for reading and writing data, 13 is a flexure made of a leaf spring that supports the magnetic head 12, and 14 is a swing arm that supports the flexure 13.
The top can be moved in the tracking direction. Reference numeral 15 is a rotating shaft of a swing arm, 16 is a coil of VCM, 17 is an upper magnet, 18 is a lower magnet, 19 is a circuit board on which a signal processing circuit is mounted, and 20 is a shroud and a circuit board which are integrally fixed to another device. It is a frame for doing.

Next, the operation of the magnetic disk device will be described. When the rotating hub 4 is activated, the attached magnetic disks 8a to 8c also start rotating at the same time. Magnetic head 12
When the magnetic disk 8 is activated, it is pressed against the magnetic disk by the downward spring force of the flexure 13 and slides on the magnetic disk 8. Due to the positive pressure that is generated on the magnetic head 12 to lift the magnetic head 12 upward, the magnetic head 12 floats above the magnetic disk. When the rotation speed becomes constant and the positive pressure becomes constant, the fluctuation of the flying height of the magnetic head 12 also disappears, and the magnetic head 12 is in a constant floating state. When this happens,
The magnetic head 12 moves to a target track and reads and writes information.

[0006]

However, due to the miniaturization and large capacity of magnetic disk devices, it has become necessary to expand the data area on the magnetic disk surface and increase the recording density.

However, the magnetic disk 8 and the spacer 9
Since the clamper 10 mounted and attached to the rotary hub 4 is fastened to the upper end portion of the rotary hub 4 by the screw 11, uneven elastic deformation occurs due to the axial force concentration of the screw near the screw receiving portion of the clamper 10. . Therefore, since a non-uniform force is applied to the magnetic disk 8c pressed by the clamper 10 in the circumferential direction, distortion and undulation as shown in FIG. 10 occur, and thus the inner circumference of the magnetic disk 8c during operation of the magnetic disk device. In the area, due to the distortion and undulation, the floating gap between the magnetic head 12 and the magnetic disk 8c fluctuates instantaneously. For example, when the number of clamp fastening screws is 6, the magnetic head output is also the magnetic disk 8 as shown in FIG.
The number of times of change is the same as the number of screws, 6 times during one rotation of a.
A value obtained by dividing the minimum value of the magnetic head output by the maximum value is expressed as a percentage. When the modulation becomes small, the fluctuation of the output wave causes deterioration of the S / N of the reproduction output signal. The error rate is lowered due to the increase in the time jitter of the data reproduction pulse, resulting in inaccurate data recording / reproduction. In addition, there is a problem that positioning of the magnetic head to a target track, writing and reading of data cannot be performed accurately, or a failure such as contact with a magnetic disk occurs due to a decrease in flying height.

[0008] Further, thinning of magnetic disk device parts has also been considered from the market demand for thinning, but thinning of a magnetic disk increases deformation due to temperature change and stress concentration at the time of mounting and mounting by screws. Hiring is difficult.

[0009]

In order to solve the above problems, the present invention provides a cylindrical protrusion having a diameter smaller than the outer diameter of the rotary hub at the uppermost portion of the rotary hub and having a diameter slightly larger than the outer diameter of the cylindrical protrusion. Providing a protrusion, press-fit the inner diameter side of a thin ring-shaped clamp member, and fix it between the upper end of the magnetic disk mounting mounting cylindrical portion of the rotating hub and the protrusion so that the magnetic disk is pressed by the outer periphery of the clamp member. Attach it to the spindle motor rotating hub.

[0010]

According to the present invention, it is possible to prevent deformation such as distortion and waviness of the inner peripheral portion of the magnetic disk which is caused by elastic deformation of the clamper generated by fastening the screw between the clamper for pressing the magnetic disk and the upper surface of the hub. It is possible to make the flying of the magnetic head stable in the inner circumference of the magnetic disk during the operation of the magnetic disk device, and to improve the positioning accuracy by uniforming the output of the magnetic head and write and read data accurately. It is possible to improve the reliability of the magnetic disk device.

Further, by press-fitting the thin clamp member into the rotary hub and mounting and mounting the magnetic disk, the magnetic disk mounting portion can be made thin, and the magnetic disk device can be made thin.

[0012]

【Example】

(Embodiment 1) An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, in the present invention, all the mechanical parts of the magnetic disk device except the magnetic disk mounting mechanism for clamping the magnetic disk 8 are the same as the conventional ones. Further, the magnetic disk receiving portion and the mounting portion for supporting the magnetic disk 8 of the rotary hub 4 are the same as the conventional ones, but as shown in FIG. 4, the uppermost clamper 21, 22 insertion portion is a cylinder for mounting the magnetic disk. A protrusion 24 having a diameter slightly larger than the outer diameter of the cylindrical protrusion so that the clamper 21 or 22 does not come off after press-fitting is provided at a height where the clamper 21 can be fitted from the upper end of the portion.
The height of this protrusion is lower than that of the magnetic disk 8c.

FIG. 2 is a perspective view of the clamper according to the first embodiment of the present invention, and 21 is a ring-shaped clamper. This clamper 21 has a hole in the center thereof which is coaxial with the outermost circumference.

Reference numeral 22 in FIG. 3 is also a clamper having a hole coaxial with the outermost periphery in the center portion, but a slit 23 is formed toward the outside of the hole in the center portion to realize stress relaxation.

Next, a clamping method using the clamper of this embodiment will be described with reference to FIGS. As shown in FIG. 1, in the magnetic disk 8, the inner surface of the lower surface of the lowermost magnetic disk 8a is supported by the large diameter portion of the bottom of the rotary hub 4, and a spacer 9a is provided between the upper surface of the magnetic disk 8a and the lower surface of the magnetic disk 8b. Disk 8b upper surface and magnetic disk 8c
A spacer 9b is inserted between the lower surfaces, and the inner peripheral portion of the upper surface of the magnetic disk 8c is pressed by the clampers 21 and 22. At this time, the clampers 21 and 22 have inner diameters equal to those of the rotary hub 4.
When the magnetic disk 8c is elastically deformed concentrically by being press-fitted into the projection 24, the reaction force presses the magnetic disk 8c by the outer diameter portion in contact with the inner peripheral portion of the magnetic disk 8c.

Accordingly, the deformations of the clampers 21 and 22 are concentrically equalized, and the deformation of the magnetic disk 8c also occurs concentrically as shown in FIG. 6 similarly to the clampers 21 and 22 to perform clamping with less distortion and undulation. be able to.

The material of the clamper is SUS type or spring steel plate, and the thickness thereof is about 0.3 to 0.8 n. The radius of the slit is connected to the pressing force of the media (D +
d) / 2 or less is desirable (D: outer diameter d: inner diameter).

(Second Embodiment) A second embodiment will be described with reference to FIG.

The uppermost magnetic disk 8c and clamper 2
When a ring-shaped flat spacer 25 having the same thickness as that of the magnetic disk is inserted between Nos. 1 to 22 so that the uniform pressing to the magnetic disk 8c is impaired due to the nonuniform portion of the clamp material. But spacer 2
5 makes it possible to equalize the pressing force and further reduce the distortion and waviness of the magnetic disk 8c.

The specific shape of the slit formed in the clamp of the above embodiment is not limited to that of the embodiment.

As a result, during the operation of the magnetic disk device, the floating of the magnetic head is kept stable in the inner peripheral portion of the magnetic disk, and the output of the magnetic head is made uniform as shown in FIG. Is accurately written and read, so that the reliability of the magnetic disk device is improved and the magnetic disk 8 and the magnetic head 12 are
It is possible to reduce the breakdown of contacts and the like.

Further, as is clear from FIG. 8, the height of the conventional magnetic disk mounting mechanism can be made 87% by making the clamper thin without using screws.

[0023]

As described above, according to the present invention, 1. During the operation of the magnetic disk device, the floating of the magnetic head is kept stable in the inner circumference of the magnetic disk, and the positioning accuracy is improved by uniforming the magnetic head output, and data writing and reading are performed accurately. The reliability of the magnetic disk device is improved.

2. By press-fitting a thin clamp member into the rotary hub and mounting and mounting the magnetic disk, it is possible to realize a thin magnetic disk mounting portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a clamper according to an embodiment of the present invention.

FIG. 3 is a perspective view of a clamper according to an embodiment of the present invention.

FIG. 4 is an enlarged view of the mounting mechanism of the magnetic disk of FIG.

FIG. 5 is an enlarged view of a magnetic disk mounting mechanism according to a second embodiment of the present invention.

FIG. 6 is a top view of distortion of a magnetic disk according to an embodiment of the present invention.

FIG. 7 is a diagram showing head output in one embodiment of the present invention.

FIG. 8 is a sectional view showing a difference in height between the magnetic disk mounting mechanism of the present invention and a conventional one.

FIG. 9 is a sectional view of a conventional magnetic disk device.

FIG. 10 is a top view of distortion of a conventional magnetic disk

FIG. 11 is a diagram showing a head output of a conventional mounting mechanism.

[Explanation of symbols]

 1 Shroud 2 Spindle motor base 3 Bearing 4 Rotating hub 5 Stator core 6 Stator winding 7 Permanent magnet for spindle motor 8 Magnetic disk 9 Spacer 10 Disc-shaped clamper 11 Screw 12 Magnetic head 13 Flexure 14 Swing arm 15 Swing arm rotating shaft 16 Coil 17 Upper Permanent Magnet 18 Lower Permanent Magnet 19 Circuit Board 20 Frame 21 Clamper of the Present Invention 22 Clamper with Slit of the Present Invention 23 Slit 24 Protrusions 25 Spacer for Stress Relaxation

Claims (1)

[Claims] 1. A magnetic disk apparatus having a magnetic disk mounting mechanism for mounting and mounting a magnetic disk on a rotary hub of a spindle motor by a clamp member, the magnetic disk having a diameter smaller than an outer diameter of a cylindrical portion on which the magnetic disk of the rotary hub is mounted. Cylindrical part for mounting the magnetic disk of the rotary hub by press-fitting the inner diameter side of the thin ring-shaped clamp member into the protrusion part slightly larger than the outer diameter of the cylindrical protrusion part provided on the uppermost cylindrical protrusion part. A magnetic disk device characterized by being fixed between the upper end and the protrusion so that the magnetic disk is evenly pressed by the outer periphery of the clamp member and mounted and attached to a spindle motor rotating hub.