JP2002298567A - Cover structure of disk unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a top cover of a disk unit which is capable of reducing the vibration of the top cover itself to the disk device in which a plurality of the vibration are generated by different frequency components and the noise occurring therein. SOLUTION: The surface in contact with the outdoor air of the top cover for hermetically closing a mechanism section together with a base is provided with a vibration damping mechanism for preventing the vibration and noise generated by driving of a disk. This vibration damping mechanism comprises a restraining plate consisting of metal and plural viscoelastic materials varying in vibration damping mechanism. As a result, the disk device which effectively reduces the vibration of the plural segments consisting of the plural frequency characteristics generated in the top cover and suppresses the noise generated in consequence of this vibration is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover structure for a disk drive, and more particularly to a cover structure for reducing vibration and noise caused by rotation of a disk of the disk drive.

[0002]

2. Description of the Related Art In a disk drive, it is known that vibration and noise are generated by rotation of a disk during a seek operation. The vibration and noise are generated when the rotational vibration of the disk is transmitted to the housing through a rotating shaft or the like.
Therefore, it is known that the generation of such vibration and noise is suppressed if the entire housing is formed by a die-casting method capable of obtaining high rigidity.

[0003] In addition, the rotating shaft of the disk drive and the top cover are attached to the outer surface of the top cover around the screws that are connected to each other.
A single horseshoe-shaped damping plate is adhered, and the vibration of the cover is absorbed by the damping plate to suppress noise.
No. 28955 or JP-A-11-23286.

Japanese Patent Application Laid-Open No. 9-128595 discloses a structure in which one horseshoe-shaped damping plate is attached to an outer surface of a top cover around a screw for connecting a rotating shaft of a magnetic disk device and a top cover to each other. ing. This damping plate has a structure in which a restraining plate made of metal and a viscoelastic material are bonded together, and is arranged in a recess having the same shape as the damping plate provided on the top cover. With such a structure, vibration at the top cover is absorbed to suppress noise.

In a disk drive, vibration is generated mainly by the rotation of a spindle motor and a seek operation of a head by an actuator, and the vibration is also transmitted to the top cover. It is a major part of the release.

[0006] Therefore, by attaching the above-described vibration damping plate to the top cover, the energy of the vibration generated in the top cover is converted into thermal energy due to expansion and contraction or shear deformation of the viscoelastic material. The vibration of the top cover is reduced, and the noise radiated from the top cover surface due to the vibration is also reduced.

[0007] The viscoelastic material of the vibration damping plate in the prior art is selected to reduce the vibration of a single frequency band of interest, and one vibration damping material having one kind of viscoelastic material is used. The plate reduces noise caused by vibration of the top cover centering on the frequency band.

However, the frequency range of the noise radiated from the top cover of the disk drive is wide, for example, low, medium,
Many have high peaks in a plurality of high frequency bands. The locations where vibrations are generated at each frequency, which is a major noise source, are also different, and a single damping plate having one type of viscoelastic material optimally reduces noise in all frequency bands. It is impossible.

Therefore, in the present invention, the vibration and the noise caused by the vibration can be effectively formed by bonding a vibration damping plate having a plurality of viscoelastic materials having different vibration damping characteristics in the inner surface direction of the restraining plate to the outer surface of the top cover. The purpose is to reduce the amount. For example, at a plurality of locations vibrating at a certain frequency, a vibration damping plate in which a plurality of viscoelastic materials that most effectively reduce the vibration at that frequency are arranged in an in-plane direction is formed on the outer surface of the top cover. Paste in the recess. With such a configuration, it is possible to point out the top cover vibration and noise at each frequency.

In the prior art described above, a viscoelastic material which is attached to the top cover and which effectively reduces the vibration of the one largest frequency band of interest is selected as the viscoelastic material of the damping plate. The noise caused by the vibration of the top cover centered on the frequency band is optimally reduced.

However, the frequency range of the noise generated from the top cover of the magnetic disk drive is wide, for example, low and high.
Many have high peaks in the middle and high frequency bands, respectively. Furthermore, the location where vibration mainly occurs at each frequency is also different, and it is difficult to optimally reduce noise in all frequency bands with a single damping plate having one type of viscoelastic material.

The vibration damping plate is provided with a concave portion in the top cover by utilizing the internal space of the apparatus, and is disposed in the concave portion. In the internal space of the device, there are places where there is room for the top cover, such as on the magnetic disk, and places where there is not enough space, such as on the voice coil motor, the magnetic head movable part, and the upper part of the spindle motor. In the above-described prior art, a top cover recess is provided on a magnetic disk, which is a place where there is sufficient space, and one damping plate is arranged.

However, in a place where there is not enough space, a concave portion having the same depth as that of a place where there is enough space cannot be provided. It was difficult to reduce the vibration.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to optimally reduce the top cover vibration of each frequency, which is a problem, and the noise caused thereby. The top cover has a damping plate in which a plurality of viscoelastic materials having different damping characteristics are arranged in an in-plane direction, which can effectively reduce the vibration and noise of the entire top cover by maximizing a space inside the device. The purpose is to provide a disk device.

[0015]

[Means for Solving the Problems]

A disk drive according to the present invention includes a spindle motor for mounting a recording disk and an actuator for driving a carriage for mounting a head for writing information on the disk on a base. A disk device, which is provided with a vibration damping mechanism for preventing vibration and noise generated when the disk is driven on a side of the cover which is sealed by a cover attached to a base and which comes into contact with outside air, The mechanism consists of a restraining plate made of metal,
And a second viscoelastic material having a second vibration characteristic different from the first vibration characteristic.

By using such a damping plate,
It is possible to reduce the vibration of each part of a plurality of main frequencies generated on the top cover of the disk device and the noise caused thereby.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment)

FIG. 1 is a schematic diagram of a magnetic disk drive according to the first embodiment, which is shown in FIG. FIG. 4 is an enlarged view of the top cover. Further, FIG. 3 shows a vibration mode diagram at a certain frequency of the top cover.

In a base 201, a disk-shaped magnetic disk 202 and a spindle motor 20 for rotating the disk 202 are driven.
3 and an oscillating actuator 205 for positioning a magnetic head 204 for recording / reproducing magnetic recording information on the magnetic disk 202 on the magnetic disk 202, and a voice coil motor 206 as a driving means for the oscillating actuator 205. And is sealed by a top cover 207.

When recording / reproducing, the magnetic disk 202 is driven to rotate by the spindle motor 203. Further, the swing type actuator 205 is swingably driven by the voice coil motor 206, and the magnetic head 20 is driven.
A seek operation is performed in which No. 4 is positioned on the target magnetic disk 202. At this time, vibration is generated by the rotational drive of the spindle motor 206 and the seek operation of the magnetic head, and the vibration is propagated through the solid and the housing 201 and the top cover 207 also vibrate.

In addition, rotation of the magnetic disk 202 causes air vibration, which is propagated to the top cover 207 by air propagation.
Vibrates.

These vibrations generate noise having a wide range of frequency components.

Further, the vibration of the top cover 207 is different at the abdomen of the vibration which is most shaken at the frequency.

For example, as shown in FIG. 3A, the resonance frequency A at which the portion 301 in FIG.
In FIG. 2B, there is a resonance frequency B at which the portion 302 in FIG. In such a case, it is desirable to provide a vibration damping member that most effectively reduces vibration at that frequency in each section.

In view of the above, in a place where the top cover surface is mainly vibrating at each frequency, a vibration damping plate in which a plurality of viscoelastic materials that most effectively reduce the vibration at that frequency are arranged in the in-plane direction is used. Affix to the concave portion formed on the outer surface of the cover.

In this embodiment, the viscoelastic material 402b that most effectively reduces the frequency of AHz and the viscoelastic material 402c that most effectively reduces the frequency of BHz are 301 and 302 parts of the top cover recess 403, respectively. Are attached to the restraining plate 402a so as to be the center, and constitute the damping plate 402. Here, the restraining plate 402a is made of a metal such as stainless steel, and the viscoelastic material 402b.
402c is made of a polymer material that exhibits a mechanical behavior combining viscosity of a fluid and elasticity of a spring, and has a property of attenuating vibration by converting vibration energy into thermal energy by its own elastic deformation. have. The recess 403 provided in the top cover is
When the disk drive 02 is attached to the outer surface of the top cover, it is necessary to prevent the thickness of the entire disk device from exceeding the specified thickness of the disk device.

Further, the concave portion 403 needs to be formed at a depth that does not affect the mounting of components inside the disk device.
A concave portion 403 having a depth corresponding to a space where there is room in the disk device is provided. For example, a concave portion having a large depth is formed in the space A portion on the disk 202 in FIG. 2 and particularly in the space C portion where the mounted components are not mounted.

If the outer shape of the recess 403 is not so large in the space inside the disk device as on the voice coil motor 206, the recess 4 having a depth avoiding the recess is used.
03 is formed. For example, in the space B on the movable region of the magnetic head 204 in FIG.

By adopting the configuration of the top cover as in the present embodiment, it is possible to effectively reduce the vibration of each part (abdomen) of the top cover that oscillates at the main frequency and the noise caused by this. It becomes possible.

(Second Embodiment)

FIG. 6 is an enlarged view of the top cover according to the second embodiment of the present invention. In addition, DD in FIG.
A cross-sectional view is shown in FIG.

In the disk device according to the first embodiment of the present invention described above, in addition to the voice coil motor 206, the spindle motor 502 (part E in the drawing) and the movable range of the magnetic head 504 (part B in the drawing) If there is no room in the upper space, the vibration damping plate 4 described in the first embodiment is used.
Top cover recesses 604 and 60 in which two damping plates 602 and 603 each having an outer shape excluding the upper part of the space of the portion E and the portion B from the outer shape of No. 02 are separately formed by separate members.
5 are respectively adhered with an adhesive or the like.

Further, these two damping plates 602, 60
3 are viscoelastic materials 602b and 602 having different vibration damping characteristics, respectively.
03b, it is possible to effectively reduce the vibration of each part and reduce the noise caused by this.

With such a configuration, the damping plate 40
2 has a space in the space with the top cover 207 inside the disk device, for example, a portion A and a portion C facing the disk 202 in FIG. Even when the magnetic head 204 is divided in the in-plane direction by the opposing portion B on the movable portion of the magnetic head 204, the vibration damping plate 40 suitable for suppressing the vibration of each portion is provided.
By attaching 2, it is possible to reduce noise caused by vibration.

(Third Embodiment)

FIG. 7 is an enlarged view of the top cover according to the third embodiment of the present invention.

In the disk drive according to the first embodiment of the present invention described above, even if there is not enough room for the top cover 505 on the magnetic disk 503 as in the A and C portions, some space is provided in the space. A third top cover recess 707 having a depth that does not hinder the movement of the magnetic head 709 is provided in a portion B on the movable range of a certain magnetic head 709,
A third damping plate 704 is arranged. This damping plate 704
The thickness of the other vibration damping plates 702 and 703 is reduced so as to fit within the specified thickness of the disk device, and is formed so that the outer surfaces are all the same. Here, the damping plate 70
Sample No. 4 is slightly inferior in damping effect because it is thinner than the damping plates 702 and 703, but a certain damping effect can be expected.

As in this embodiment, the vibration of the entire top cover is effectively reduced by maximizing the space in the disk device and bonding a plurality of vibration damping plates in the in-plane direction of the outer surface of the top cover. , And the noise caused by this can be reduced.

Also, in a disk drive, the magnetic head may fly due to an impact applied from the outside during operation of the disk drive, and the rebound may damage the magnetic head or the magnetic disk surface. Has been seen. The jump width is limited by reducing the distance between the magnetic head 709 and the lower surface of the top cover recess 707 as in the present embodiment, and the magnetic head 709 itself is damaged due to the jump of the magnetic head 709 and the contact of the magnetic head 709 with the magnetic head 709. Damage to the magnetic disk 708 can be reduced.

Further, the vibration of the top cover concave portion 707 is optimally reduced by the vibration damping plate 704, so that when the magnetic head 709 comes into contact with the lower surface of the top cover concave portion 707 due to a splash caused by an impact during operation. Magnetic head 70
9 is prevented from being accelerated by the vibration of the top cover and rebounding, and colliding strongly with the magnetic disk 708.

(Fourth Embodiment)

FIG. 7 is an enlarged view of the top cover according to the fourth embodiment of the present invention. Since the present embodiment is a modification of the third embodiment, the embodiment will be described with reference to the same drawing.

In this embodiment, the distance 71 between the lower surface of the top cover recess 705 facing the magnetic disk 708 and the surface of the magnetic disk 708 described in the third embodiment is described.
0 is small enough that the magnetic disk 708 does not collide with the top cover 701 even when the magnetic disk 708 is deformed when the disk device receives an external impact, and its size is, for example, about 150 μm.
It is formed to have an interval of m.

Further, a vibration damping plate 702 using a viscoelastic material 702b having a frequency characteristic suitable for reducing the vibration according to the frequency characteristic of the vibration at this location is disposed in the concave portion 705. I have. Thereby, the magnetic disk 5
03 and the top cover recess 507 produce a squeeze air bearing effect, and the vibration of the magnetic disk 503 can be attenuated.

Here, the squeeze air bearing effect will be briefly described. For example, a flat plate (hereinafter referred to as squeezed air) with a portion corresponding to the magnetic disk surface having a circumferential angle of 90 degrees or more around the center of the rotation axis of the magnetic disk and a width of about 20 mm in the radial direction from the center of the rotation axis. When the space is made sufficiently small, the magnetic disk rotates and vibrates, so that air in and out of the gap enters and exits, and the viscosity of the air causes the magnetic disk to vibrate. A viscous resistance force proportional to the vibration speed of the magnetic disk acts on the magnetic disk. The principle of the squeeze air bearing is that the viscoelastic resistance force attenuates the vibration caused by the flutter caused by the rotation of the magnetic disk.

According to the configuration of the third embodiment described above,
The top cover recess 705 plays the role of the squeeze air bearing plate, and the magnetic disk 503 and the top cover recess 705 form a squeeze air bearing. I do.

By the squeeze air bearing effect, it is possible to reduce the vibration of the magnetic disk 503, which is one of the vibration sources for vibrating the top cover 505, and to improve the positioning accuracy of the head in the disk device. It becomes possible.

Also, wind noise when the magnetic disk 503 is rotated at a high speed by the spindle motor can be effectively reduced.

Further, since the vibration damping plate 702 is disposed in the top cover recess 705 serving as the squeeze air bearing plate described above in the present embodiment, the vibration of the top cover 505 itself is appropriately reduced. , The effect of reducing disk flutter is further enhanced.

[0052]

As described above in detail, according to the present invention, it is possible to appropriately absorb the vibration of the top cover in which a plurality of parts vibrate with a plurality of frequency components, and the vibrations caused by this vibration are generated. Noise can be appropriately reduced. That is, by adopting the top cover as the top cover of the disk drive using a damping plate in which a plurality of viscoelastic materials having different damping characteristics are arranged in the in-plane direction, a plurality of main frequencies generated in the top cover of the disk drive are obtained. It is possible to reduce the vibration of each part and the noise caused thereby.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the structure of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a sectional view illustrating the structure of the magnetic disk drive according to the embodiment of the present invention.

FIG. 3 is a resonance distribution diagram illustrating a vibration state of a top cover of the magnetic disk device according to the embodiment.

FIGS. 4A and 4B are a front view and a cross-sectional view illustrating a structure of the top cover according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining the structure of the magnetic disk drive according to the embodiment of the present invention;

FIG. 6 is a front view and a cross-sectional view illustrating a structure of a top cover according to a second embodiment of the present invention.

FIG. 7 is a front view and a cross-sectional view illustrating a structure of a top cover according to a third embodiment of the present invention.

[Explanation of symbols]

 10 Case 16 Magnetic disk 18 Spindle motor (SPM) 20 Magnetic head 22 Carriage assembly 24 Voice coil motor (VCM) 201 Base 202 Magnetic Disk 203: Spindle motor (SPM) 204: Magnetic head 205: Swing type actuator 206: Voice coil motor (VCM) 301: Region with the largest amplitude in case of resonance frequency A 302: Resonance frequency B In this case, the region having the largest amplitude 401... Top cover 402... Vibration damping plate 1 402a... Restraint plate 402b... Viscoelastic material b 402c. SPM) 504: Magnetic head 505: Top cover 601: Top cover 602: damping plate 1 602b: visco-elastic material 1 603: damping plate 2 603b: visco-elastic material 2 604: concave portion 1 605: concave portion 2 606: magnetic disk 607: magnetic head 701: top Cover 702: damping plate 1 703: damping plate 2 704: damping plate 3 705: recess 1 706: recess 2 707: recess 3 708: magnetic disk 709: magnetic head 710 interval

Claims (8)

[Claims] 1. A spindle motor for mounting a disk and an actuator for driving a carriage mounting a head for writing information on the disk are provided on a base, and the spindle motor and the actuator are covered by a cover attached to the base. The disk device is provided with a vibration damping mechanism for preventing vibration and noise generated at the time of driving the disk on a side of the cover that comes into contact with the outside air.
A constraint plate made of metal, a first viscoelastic material having a first vibration characteristic, and a second viscoelastic material having a second vibration characteristic different from the first vibration characteristic. Characteristic disk device. 2. The method according to claim 1, wherein the first and second viscoelastic materials have a vibration characteristic corresponding to a frequency for reducing vibration of different vibration characteristics generated in a plurality of regions of the cover. The disk device as described above. 3. The disk device according to claim 1, wherein the top cover has a concave portion on a side contacting the outside air, and the restraining plate is disposed in the concave portion. 4. The disk device according to claim 1, wherein the restraining plate is divided for each of the first and second viscoelastic materials having different vibration characteristics. 5. The top cover has a concave portion on a side that comes into contact with the outside air, and the concave portion has a first portion having a different vibration characteristic.
2. The disk device according to claim 1, wherein a concave portion divided for each of the second viscoelastic materials is formed. 6. A plurality of concave portions provided on a side of the top cover that comes into contact with the outside air have different depths in accordance with the arrangement of components in the internal space of the disk device. Item 6. The disk device according to item 5. 7. The thickness of the plurality of restraint plates,
7. The disk device according to claim 6, wherein the disk device has a plurality of different thicknesses corresponding to the depths of the plurality of divided concave portions having a depth corresponding to the component arrangement in the internal space of the disk device. 8. A concave surface formed in the direction of the closed space of the top cover and a surface of the disk have a predetermined gap, and the concave surface and the disk provide a damping force based on a squeeze air bearing principle. 4. The disk device according to claim 3, wherein the disk device is formed so as to have an interval that occurs.