JP2003249053A - Disk unit with disk flutter damping cover and disk flutter damping cover used for the unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk unit and a disk flutter damping cover which have a protecting function of preventing a cover and a disk from coming into contact with each other by managing a shroud gap for deterring the disk from fluttering by a single component. <P>SOLUTION: The disk unit has the flutter damping cover 20 composed of a cylindrical side wall 20 of internal-diameter size which has a gap for restricting a flow of air generated by the rotation of the magnetic disks 12a and 12b opposite outer circumferential end parts of magnetic disks 12a and 12b and a top plate 21 which is formed connecting with the cylindrical side wall 22 and has the gap deterring the magnetic disk 12a from fluttering opposite the top surface of the magnetic disk 12a. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device having a disk flutter damping cover for suppressing disk flutter vibrations excited by air as a magnetic disk device and an optical disk device rotate at high speed, and a disk flutter used in the device. Regarding damping cover.

[0002]

2. Description of the Related Art A magnetic disk device (HDD), which is a disk storage device, is always required to have high density and high speed. In particular, in the magnetic disk device for enhanced use, a high rotation model with a disk rotation speed of 7200 rpm has been commercialized, and in the future, a higher recording density will be required under the condition of a further high speed rotation of 10,000 rpm or more. In particular, it is strongly required to improve the track density, but as the disc rotation speed increases, vortices are formed in the air flow between the disc plates, the air around the disc is disturbed, and the natural vibration of the disc is excited. Vibration of the disk called disk flutter occurs, which causes a track shift when positioning the head.

There are various kinds of vibrations of the disk spindle, and among them, the rocking unbalance mode in which the disk and the shaft tilt and vibrate in the same phase or in the opposite phase is the main cause of track deviation during head positioning. The vibration of the disk that causes the track deviation includes non-rotational synchronous vibration generated from the rolling bearing. Although fluid bearings have been used to eliminate this, even if fluid bearings are used, the advantages of fluid bearings cannot be utilized without suppressing the aerodynamically excited disk flutter. Therefore, in recent years, damping and removing the disk flutter has been a major issue for developing a high-performance magnetic disk device.

As a solution to this problem, in order to remove air vortices between the disk surfaces and eliminate air turbulence around the disk outer circumference, a hole is made in the spacer ring of the clamp mechanism in the center of the disk, and the air is centrifuged during rotation. A structure has been proposed in which air is ejected from the central portion by using force. Further, there has been proposed a structure in which a turbulent flow is prevented by bringing a hermetic cover around the disk close to the side surface of the disk. Further, a method of locally inserting a partial plate called a spoiler between the disk layers in order to prevent cell-like vortices generated between the disk plates and flutter of the head suspension due to the vortex has been proposed. However, these are not to suppress the vibration of the disk plate by damping, but to prevent the generation of turbulent flow or vortex between the disk layers. Moreover, these methods were not always effective in suppressing flutter over a wide frequency range.

On the other hand, although a plan to use a ceramic disk plate having a large attenuation has been proposed, it has a large demerit because it is expensive and requires a change in the production technique. As a solution to the above, Japanese Patent Laid-Open Nos. 2000-348465 and 2
000-322870, JP-A 2000-34871.
Prior art such as the issue is disclosed. In the prior art, the gap between the disk and the side wall is made small, and a shroud wall having a rectifying function is installed, or a protrusion is provided at the gap between the disk end and the gap between the disk and the side wall is made small. It is characterized by suppressing flutter.

[0006]

However, the above-mentioned prior art requires two parts for forming a squeeze plate near the disk surface, which is effective as a flutter reduction effect, and for forming a shroud plate on the disk side surface. Become.

Further, in order to obtain the squeeze effect, it is necessary to dispose the squeeze plate immediately above the disk.
Therefore, it is difficult to give a squeeze effect to the cover that forms the outer shape of the magnetic disk device, because the cover that forms the outer shape of the magnetic disk device must consider the generation of external force.

Therefore, an object of the present invention is to manage the thrust gap for obtaining the squeeze effect and the shroud (radial) gap for restricting the inflow and outflow of air entering the disk and suppressing the flutter by one part at the same time. Along with
It is an object of the present invention to provide a disk device having a disk flutter damping cover having a function of protecting a disk that prevents contact between the cover and the disk constituting the outer shape of the magnetic disk device, and a disk flutter damping cover used in the device.

[0009]

In order to achieve the above object, a disk device according to the present invention comprises a spindle mechanism for rotating the disk, a housing for accommodating the disk and the spindle mechanism, and an outer peripheral end portion of the disk. And a cylindrical side wall having an inner diameter and having an interval for restricting the flow of air generated by the rotation of the disk, and connected to the cylindrical side wall, facing the upper surface of the disk and suppressing the flutter of the disk. And a disk flutter damping cover composed of a top surface having an interval.

According to the above-mentioned structure, it is possible to reduce the flutter generated on the disc, and to regulate the thrust gap for obtaining the squeeze effect and the inflow / outflow of air entering the disc. It is possible to provide a disk device having a disk flutter damping cover capable of simultaneously managing a shroud (radial) gap for suppressing flutter with one component.

Further, the disk device according to the present invention is characterized by further comprising a top cover which is disposed above the disk flutter damping cover so as to face the disk flutter damping cover with a predetermined gap and closes the casing. It is a thing.

According to the above-mentioned structure, the thrust gap for obtaining the squeeze effect and the shroud (radial) gap for restricting the flutter of the disc by restricting the inflow and outflow of the air entering the disc are one part. A disk device having a disk flutter damping cover that can prevent the contact between the top cover and the disk even if external stress is applied to the top cover forming the outer shape of the magnetic disk device. Can be provided.

Further, in the disk device according to the present invention, the housing has a side surface portion, and a positioning portion for positioning the disk flutter damping cover is provided inside the side surface. It is characterized in that it is attached by being sandwiched so that the outer periphery of the cylindrical side wall of the cylindrical shape contacts the positioning portion.

According to the above-mentioned configuration, it is possible to provide a disk device having a disk flutter damping cover which can simplify the mounting work and can accurately position the disk flutter damping cover. Become.

Further, the disk flutter damping cover used in the disk device according to the present invention is a disk flutter damping cover used in a disk device having a spindle mechanism for rotating the disk and a housing accommodating the disk and the spindle mechanism. In the cover, a cylindrical side wall facing the outer peripheral end of the disk and having an inner diameter dimension having a space for restricting the flow of air generated by the rotation of the disk,
A top surface that is connected to the cylindrical side wall, faces the top surface of the disk, and has a space that suppresses the flutter of the disk.

According to the above-mentioned structure, it is possible to reduce the flutter generated on the disk, and the thrust gap for obtaining the squeeze effect and the inflow / outflow of air entering the disk are regulated. It is possible to provide a disk flutter damping cover capable of simultaneously managing a shroud (radial) gap for suppressing flutter with one component.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the disk device of the present invention is applied to a hard disk drive (hereinafter referred to as HDD) which is a magnetic disk device will be described in detail below with reference to the drawings.

FIG. 1 is an opening perspective view showing the internal structure of the HDD according to this embodiment. As shown in FIG.
Is a rectangular box-shaped base casing 10 having an open upper surface, and a top cover 23 that is screwed to the base casing 10 by a plurality of screws (not shown) described later with reference to FIG. 2 to close the upper end opening of the base casing 10. And have.

In the base casing 10, there are two magnetic disks 12a and 12b and these magnetic disks 12a and 12b.
A magnetic disk supporting device 15 having a spindle motor 13 that supports and rotationally drives b is provided. Further, in the base casing 10, the magnetic disks 12a, 12
b, a plurality of magnetic heads 3 for recording and reproducing information
2, these magnetic heads 32 are connected to the magnetic disks 12a, 1
2b, a carriage assembly 14 that is movably supported, a voice coil motor (hereinafter referred to as VCM) 16 that rotates the carriage assembly 14 to position the magnetic head 32 on a predetermined track on the magnetic disks 12a and 12b, and A board unit 17 having a preamplifier and the like is housed.

Further, on the outer surface of the base casing 10, a spindle motor 13, VCM 16,
Also, a printed circuit board (not shown) that controls the movement of the magnetic head 32 is screwed and positioned so as to face the bottom wall of the base housing 10.

Further, a flutter reduction cover (hereinafter referred to as a disk flutter damping cover) 20 is provided around the magnetic disks 12a and 12b to reduce flutter that occurs due to the rotation of the magnetic disks 12a and 12b. There is.

Each magnetic head 32 has a substantially rectangular slider (not shown) and a recording / reproducing MR (magnetoresistive effect) head formed on this slider, and is fixed to a gimbal portion formed at the tip of the suspension. Has been done. The four magnetic heads 32 attached to the arm 26 are arranged so that two magnetic heads 32 face each other.
It is arranged so as to sandwich a and 12b from both sides.

The carriage assembly 14 also has two support frames extending from the bearing assembly 18 in the direction opposite to the arms 26, on which VC frames are mounted.
The coil 35 forming a part of M16 is fixed.

As shown in FIG. 1, when the carriage assembly 14 is assembled in the case 10, the coil 35 fixed to the support frame 34 includes a pair of yokes 36 (only one of which is shown in the figure) fixed to the case 10. ) Between these yokes 36 and one yoke 36
The VCM 16 is configured with a magnet (not shown) fixed to the VCM 16. Then, by energizing the coil 35,
The carriage assembly 14 rotates and the magnetic head 32
Are moved and positioned on desired tracks on the magnetic disks 12a, 12b.

Next, the disk flutter damping cover 20 used in the HDD according to this embodiment will be described with reference to FIGS.
Will be described in detail. FIG. 2 shows the HD according to this embodiment.
D is a front view (FIG. 2a) showing the internal structure, a cross-sectional view (FIG. 2b) showing a cut line taken along the chain line AA ′ shown in this front view (FIG. 2a), and the top cover 2
3 is a cross-sectional view (FIG. 2c) showing a cut portion taken along the alternate long and short dash line AA ′ shown in the front view (FIG. 2a) in a state where the base casing 10 is closed by 3.

As shown in FIG. 2a, the disk flutter damping cover 20 according to the embodiment of the present invention has an outermost diameter set to be substantially the same as the magnetic disks 12a and 12b.
It has a shape that covers the magnetic disks 12 a and 12 b from the direction of the top cover 23. The disk flutter damping cover 20 has a top surface 21 having a surface facing the magnetic disks 12a and 12b that is smoothed so as to cover the magnetic disk 12a almost entirely, and a magnetic disk from the outermost periphery of the top surface 21. 12a and 12b, which are continuously formed of the same material in the rotation axis direction, have a cylindrical side wall 22 formed so as to surround the outermost circumference of the magnetic disks 12a and 12b.

Top surface 2 of the disk flutter damping cover 20
1, a magnetic disk 12a is provided near the center of the spindle motor 13 and a magnetic disk 12a is provided at the top of the disk support device 15.
An opening is provided so as not to come into contact with the disc clamper 13 for pressing the 2b. Further, the carriage assembly 14 having the magnetic head 32 mounted on the top surface 21,
A fan-shaped opening is provided so that the magnetic head 32 and the carriage assembly 14 do not collide with each other in a range in which the magnetic head 32 moves when information is read from or written to a desired track on the magnetic disks 12a and 12b.

As shown in FIG. 2b, the top surface 21 of the disk flutter damping cover 20 has an extremely high resistance necessary for suppressing flutter caused by the rotation of the magnetic disks 12a and 12b on the information recording surface of the magnetic disk 12a. It is arranged such that a narrow gap is held over the entire information recording surface. Further, the cylindrical side wall 22 formed of the same material and continuous with the top surface 21 has the magnetic disk 12a,
The magnetic disk 12 facing the outermost end of the magnetic disk 12b.
They are arranged in a state in which a very narrow gap required to regulate the flow of air generated by the rotation of a and 12b is maintained.

An interval for suppressing the flutter of the magnetic disks 12a and 12b provided between the above-mentioned magnetic disk 12a and the top surface 21 of the disk flutter damping cover 20,
The interval for restricting the air flow generated by the rotation of the magnetic disks 12a and 12b provided between the outermost peripheral ends of the magnetic disks 12a and 12b and the cylindrical side wall 22 of the disk flutter damping cover 20 will be described later. This will be described in detail with reference to FIG.

The disk flutter damping cover 20 according to the embodiment of the present invention is formed by using an elastic material such as plastic having excellent workability. However, the material is not limited to the elastic material, and any material capable of continuously forming the top surface 21 and the cylindrical side wall 22 can be formed by pressing a metal material such as a stainless material having excellent surface accuracy by pressing the disk flutter control. The vibration cover 20 may be formed.

FIG. 3 shows the continuous attribute of the top surface 21 and the cylindrical side wall 22 of the disk flutter damping cover 20 according to the present embodiment, and the disk flutter damping cover 20 and the magnetic disk 12a, the disk flutter damping cover. 20
FIG. 3 is a view showing a gap between the base housing 10 and the base housing 10, and a mounting state of the disk flutter damping cover 20 on the base housing 10, and is an enlarged view of a portion surrounded by a circle A in FIGS. 1 and 2 described above. This is a state in which the top cover 23 is removed.

As shown in the enlarged view of FIG. 3, the disk flutter damping cover 20 is provided on the magnetic disk 12a.
The magnetic disk 12a has a top surface 21 that is arranged to face the magnetic disk 12a with a predetermined distance, and has a distance that suppresses flutter that occurs when the magnetic disks 12a and 12b rotate.
The outermost periphery of the top surface 21 is bent toward the bearing assembly 18 of the spindle motor 13 and is characterized by being formed of one member, that is, the same member. The bent portion is formed to have an inner diameter having a predetermined distance from the outermost peripheral ends of the magnetic disks 12a and 12b, that is, an interval that regulates the air flow generated by the rotation of the magnetic disks 12a and 12b. A cylindrical side wall 22 is formed along the outermost peripheral ends of 12a and 12b.
Furthermore, the cylindrical side wall 22 of the disc flutter damping cover 20
Is attached such that a part of its outer periphery is sandwiched at a predetermined position of the base casing 10.

A disc flutter damping cover positioning portion 37, which will be described later, is formed at a predetermined position of the above-mentioned base casing 10. The disc flutter damping cover 20 is positioned on the basis of this positioning portion 37, and the base casing is positioned. Body 10
It is attached by being sandwiched so as to contact the inside of the side surface.

Next, the structure and mounting state of the disk flutter damping cover 20 according to the embodiment of the present invention will be described in detail with reference to FIG. FIG. 4 is a more detailed cross-sectional view of the HDD shown in FIG. 2c, showing a state in which the magnetic disks 12a and 12b for recording information are attached to the hub 30 constituting the spindle motor 13. Hub 3
0 is provided with a flange portion 31 protruding in the radial direction of the magnetic disks 12a and 12b, and the lower magnetic disk 12b is mounted so as to contact the flange portion 31. Spacers (rings) 34 are arranged on the magnetic disk 12b so that the upper magnetic disk 12a and the lower magnetic disk 12b, which will be mounted later, have a predetermined space. An upper magnetic disk 12a is mounted on the spacer ring 34, and a clamper for fixing the magnetic disk 12a to the hub 30 so as to contact the magnetic disk 12a and rotate the magnetic disks 12a and 12b simultaneously with the rotation of the hub 30. 33 is provided. The clamper 33 connects the magnetic disk 12 a to the bearing assembly 18 of the spindle motor 13.
Is firmly pressed in the axial direction and is fixed to the upper portion of the hub 30 by a screw (not shown). As a result, even if the spindle motor 13 rotates at high speed, the magnetic disks 12a and 12b rotate without being displaced from the hub 30.

When the magnetic disks 12a and 12b are rotated by the spindle motor 13, a flow of air in the HDD is generated, and this flow of air causes the magnetic disk 12 to move.
It has been confirmed that the outermost peripheral ends of a and 12b are large and flutter occurs in the direction of the rotation axis. When the magnetic disk is used at a high speed of 10,000 rpm in recent years, the above flutter becomes very large. It is known that the positioning control of the magnetic head is adversely affected and that problems such as noise due to flutter occur.

The disk flutter damping cover 20 according to the embodiment of the present invention is a top surface that holds a predetermined space L1 along the information recording surface of the upper magnetic disk 12a over the entire radial surface of the information recording surface. I have 21. This interval L1 is required to be 0.3 mm or less as an interval for suppressing flutter of the magnetic disk 12a, and if the drive torque condition of the spindle motor 13 permits, the interval is generally 0.
A range of 1 mm to 0.2 mm is considered desirable.

Regarding the above-mentioned setting of the gap L1, the thickness of the air film of the squeeze air bearing is set to 0. 0 so as not to disturb the air flow caused by the magnetic disk 12a.
It is a well-known technique from the results of general experiments that the thickness needs to be 3 mm or less.

Further, in the disk flutter damping cover 20 according to the embodiment of the present invention, the outermost peripheral end portion of the above-mentioned top surface 21 is continuously bent in the axial direction of the bearing assembly 18 of the spindle motor 13 to form a magnetic disk. Cylindrical side walls 22 arranged with a predetermined interval at the outermost ends of 12a and 12b.
have. The outer peripheral surface of the cylindrical side wall 22 contacts the base casing 10, and the side wall of the base casing 10 is sandwiched by the cover positioning portion 37 provided at a predetermined position of the base casing 10 as a positioning means. Attached to. The end of the cylindrical side wall 22 is in contact with the inner bottom surface of the base casing 10.

As described above, the disk flutter damping cover 20 according to the embodiment of the present invention is formed in a bowl shape by the above-mentioned top surface 21 and the cylindrical side wall 22 continuously formed of the same material. The inner surface of the bowl-shaped disk flutter damping cover 20 causes the magnetic disks 12a, 1
It is attached to the base casing 10 with the bowl being turned upside down so as to surround the entire 2b.

Such a disk flutter damping cover 2
0 is mounted in the base casing 10 and then the base casing 10
A top cover 23 is attached to the HDD to cover the inside of the HDD so as to maintain a substantially sealed state. The top cover 23 is arranged along the upper surface of the disc flutter damping cover 20 so as to maintain a predetermined distance L2. This space L2 makes contact with the top cover 23 and the disk flutter damping cover 20 even if external stress is applied to the top cover 23 forming the outer shape of the HDD. Further, the disk flutter damping cover 20 makes the information of the magnetic disk 12a. The distance is provided to prevent the disc surface from being damaged by coming into contact with the recording surface. The distance L2 is set when the top cover 23 is deformed inward of the HDD due to external stress.
The disk flutter damping cover 20 forms a buffer for preventing the disk flutter damping cover 20 from coming into contact with the magnetic disk 12a, that is, a space for impact interference.
It must be m or more. Depending on the magnitude of external stress and the time of occurrence, the top cover 23 and the disk flutter damping cover 2 can be made as thin as possible for the entire HDD.
Generally, if the distance L2 with respect to 0 can be secured by 0.2 mm or more, a buffer spacing that can secure the time until the head is withdrawn after the external shock is detected by the shock sensor generally arranged in the HDD can be obtained. This is a well-known technique from experimental results.

The top cover 23 according to the embodiment of the present invention faces the outermost peripheral end of the disc flutter damping cover 20, that is, the top surface 21 side of the connecting portion of the top surface 21 and the cylindrical side wall 22. The protrusion 23a that comes into contact with the disc flutter damping cover 20 is provided at the position where the vibration is suppressed. When the disk flutter damping cover 20 is mounted in the HDD, the above-mentioned convex portion 23a strongly presses the outermost peripheral end of the top surface 21 of the disk flutter damping cover 20 in the axial direction of the bearing assembly 18 of the spindle motor 13. As a result, the disk flutter damping cover 20 is firmly fixed to the base casing 10.

Next, the positioning structure of the disk flutter damping cover 20 provided on the base casing 10 according to the embodiment of the present invention will be described in detail with reference to FIG. Figure 5 shows Figure 2a
On the front surface of the HDD shown in, the disk flutter damping cover 20 and the magnetic disk 12 which are the mechanical parts of the HDD.
FIG. 3 is a front view showing the base casing 10 from above with the carriage assembly 14 including a, 12b, a spindle motor 13, a magnetic head 32, and a VCM 16 removed.

Inside the side surface of the base casing 10, there is provided a cover positioning portion 37 which projects toward the inside of the base casing 10 which constitutes the mechanical portion of the HDD and is used for positioning when the disk flutter damping cover 20 is attached. Has been. The disk flutter damping cover 20 is positioned so that the outer peripheral portion of the cylindrical side wall 22 comes into contact with the cover positioning portion 37, and is attached so as to be sandwiched inside the side surface of the base housing 10. Although the cover positioning portion 37 according to the present embodiment is formed by a convex protrusion inside the side surface of the base housing 10, the shape can be variously modified, and for example, the disk flutter control can be performed inside the side surface of the base housing 10. An R-shaped notch having substantially the same shape as the outer periphery of the cylindrical side wall 22 of the vibration cover 20 may be formed, and the cylindrical side wall 22 may be positioned so as to be sandwiched in the notch.

In the present embodiment, a magnetic disk device having a plurality of magnetic disks 12a and 12b (specifically, two) mounted thereon has been described as an example. However, even if there is only one magnetic disk, the structure described above is used. It goes without saying that the same operation and effect can be obtained by using the disk flutter damping cover 60 as described above.

[0045]

As described above in detail, according to the present invention, the cylindrical side wall having the inner diameter and facing the outer peripheral end of the disk and having a space for restricting the flow of air generated by the rotation of the disk. And a bowl-shaped disk flutter damping cover, which is connected to the cylindrical side wall and is formed of the same material and is opposed to the upper surface of the disk and has a space for suppressing the disk flutter, is provided in the HDD. By doing so, it is possible to reduce the flutter that occurs on the disc, and the thrust gap for obtaining the squeeze effect,
(EN) Provided is a disk device having a disk flutter damping cover capable of simultaneously managing a shroud (radial) gap for restricting the flutter of the disk by restricting the inflow and outflow of air entering the disk. It will be possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing an internal structure of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a front view showing an internal structure of a magnetic disk device according to an embodiment of the present invention, and a sectional view taken along the line AA ′ of the same drawing.

FIG. 3 is an enlarged view of a part of a magnetic disk device and a disk flutter damping cover according to an embodiment of the present invention (enlarged view of circle A in FIG. 1).

FIG. 4 is a sectional view illustrating a magnetic disk device and a disk flutter damping cover according to an embodiment of the present invention.

FIG. 5 is a front view illustrating a cover positioning portion provided on the housing for mounting the disk flutter damping cover of the magnetic disk device according to the embodiment of the invention.

[Explanation of symbols]

10 ... Base chassis 12a, 12b ... Magnetic disk 13 ... Spindle motor (spindle mechanism) 14 ... Carriage assembly 15 ... Disk support device 16 ... Voice coil motor (VCM) 17 ... Board unit 18 ... Bearing assembly 20 ... Disc flutter damping cover 21 ... Cylindrical side wall 22 ... Top surface 23 ... Top cover 23a ... Projection 26 ... Arm 30 ... Hub 31 ... Flange 32 ... Magnetic head 33 ... Disc clamp 34 ... Spacer ring 35 ... Coil 36 ... Yoke 37 ... Disc flutter damping cover positioning portion L1 ... Gap between magnetic disk and disk flutter damping cover top surface L2 ... Top cover Disc flutter damping cover gap between top surface

Claims (9)

[Claims] 1. A spindle mechanism for rotating a disc, a housing for accommodating the disc and the spindle mechanism, and an interval facing an outer peripheral end of the disc for restricting an air flow generated by the rotation of the disc. A disc flutter damping cover comprising a cylindrical side wall having an inner diameter dimension and a top surface that is connected to the cylindrical side wall, faces the upper surface of the disc, and has a space that suppresses the flutter of the disc. Characteristic disk device. 2. The disk device according to claim 1, further comprising: a top cover that is disposed opposite to and above the disk flutter damping cover with a predetermined gap and closes the housing. 3. The housing has a side surface portion, and a positioning portion for positioning the disk flutter damping cover is provided inside the side surface, and the disk flutter control cover has an outer periphery of the cylindrical cylindrical side wall. The disk device according to claim 1, wherein the disk device is attached by being sandwiched so as to come into contact with the positioning portion. 4. The top cover has a convex portion that is in contact with the vibration damping cover at a position facing the outer periphery of the top surface of the disc flutter vibration damping cover, and when closing the housing with the top cover, 3. The disk device according to claim 2, wherein the convex portion of the top cover presses and attaches the outer peripheral portion of the top surface of the disk flutter damping cover toward the housing. 5. The disk device according to claim 1, wherein a space for suppressing flutter between the disk and the disk flutter damping cover, which is provided on a top surface of the disk flutter damping cover, is 0.3 mm or less. 6. The gap between the top cover and the upper portion of the disc flutter vibration damping cover is sufficient to protect the disc from the deflection of the top cover due to the external force applied to the top cover. The disk device according to claim 2. 7. The disk device according to claim 6, wherein a distance between the top cover and an upper part of the disk flutter damping cover is 0.2 mm or more. 8. A disc flutter damping cover used in a disc device having a spindle mechanism for rotating the disc and a housing for accommodating the disc and the spindle mechanism, the disc flutter damping cover being opposed to an outer peripheral end portion of the disc. A cylindrical side wall having an inner diameter having an interval for restricting the flow of air generated by rotation; a top surface connected to the cylindrical side wall, facing the upper surface of the disk, and having an interval for suppressing flutter of the disk; A disk flutter damping cover for use in a disk device having the following features. 9. The disk flutter vibration damping cover according to claim 8, wherein the disk flutter vibration damping cover is a bowl-like shape that is composed of the cylindrical side wall and the top surface and surrounds the disk.