JP2001331995A - Magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk device which is capable of lessening the warpage and waving generated in magnetic disks even if a clamping disk is tightened by using plural screws and assuring of the stable floating of magnetic disks. SOLUTION: An inner peripheral side 9c and disk pressing part 9a of the clamping disk 9 are elastically deformed by the tightening force of the plural screws 10 so as to bring the inner peripheral side 9c closer to a spindle hub 5 from the state that the inner peripheral side is inclined to largely part from the spindle hub 5, by which the top surface thereof is positioned nearer the surface of the disk 7 and the transmission route of the clamping force is made longer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly to a clamp disk for laminating and fixing magnetic disks to a spindle hub.

[0002]

2. Description of the Related Art FIG. 8 shows a conventional magnetic disk drive.
Spindle hub 5 rotated by spindle motor 2
, One or a plurality of magnetic disks 7 arranged at equal intervals are stacked and fixed. A magnetic head 21 is rotatably arranged on both sides or one side of the magnetic disk 7. The magnetic head 21 is fixed to the tip of the rotor actuator 17,
A voice coil motor 18 is provided at the base end of the voice coil motor 18.

When the spindle motor 2 rotates, an air flow is generated between the surface of the disk 7 and the magnetic head 21 so that the magnetic head 21 slightly flies above the surface of the disk 7. The magnetic head 21 that floats is the voice coil motor 18.
With the driving force described above, the magnetic disk 7 is rotated about the pivot center 19, and the surface of the magnetic disk 7 is moved in the radial direction to read and write data.

The flying height of the magnetic head 21 from the surface of the disk 7 is about several tens of nanometers. If dust or dust intervenes between the magnetic head 21 and the disk 7, the magnetic head 21 or the magnetic disk 7 may be damaged. Doing so may cause a failure. Therefore, the magnetic disk device is assembled in a clean room, and after assembly, the magnetic disk device is sealed with a cover 20. 1 is a base for supporting the spindle motor.

FIGS. 9 and 10 show a clamp structure of a magnetic disk drive. FIG. 9 is a sectional view, and FIG. 10 is a plan view. The spindle motor 2 is rotatably supported by the base 1 via a shaft 3 and a bearing 4.
The magnetic disk 7 and the spacer disk 8 stacked and mounted on the flange 6 of the spindle hub 5 are integrally rotatably fixed to the spindle hub 5 by clamp disks 9 and screws 10.

A clamping force for fixing the disk 7 to the spindle hub 5 is generated by passing a screw 10 through a plurality of holes 9b provided at equal intervals around the circumference of the same diameter of the clamp disk 9 and tightening the same to the spindle hub 5. I do. The transmission of the tightening force, that is, the clamp force is performed by the head 1 of the screw 10.
By pressing a portion of the clamp disk 9 where the hole 0a is in contact with the peripheral portion of the hole 9b, it is transmitted to the disk pressing portion 9a on the outer peripheral side of the clamp disk 9.

[0007]

However, in the magnetic disk drive constructed as described above, there is a problem that the clamping force is not uniform on the same circumference in the disk pressing portion 9a for pressing the disk 7.

That is, in the above magnetic disk drive,
The clamping force is generated by the tightening force of the four screws 10 arranged at equal intervals. However, the load distribution of the clamping force increases near the position where the screw 10 presses the clamp disk 9, and the clamp force is distributed on the same circumference. The strength of four periods appears in the figure.

As a result, the magnetic disk 7 pressed by the disk pressing portion 9a is also warped or undulated with four peaks on the same circumference, and the magnetic head 21 floating above the disk 7 by several tens of nm. Will hinder stable ascent. If the stable flying of the magnetic head 21 is hindered, reading and writing of magnetic data recorded on the magnetic disk 7 is adversely affected. Further, when the magnetic disk 7 and the magnetic head 21 come into contact with each other, in the worst case, the data may be damaged or the magnetic head 21 may be destroyed. Furthermore, as the density increases in the future, the flying height of the magnetic head 21 tends to decrease further, and it is considered that the demand for reducing the warpage and undulation of the magnetic disk 7 will increase.

[0010] In addition, it is generally required that the magnetic disk device guarantees normal operation even after a shock of several hundred G is applied during non-operation. So spindle hub 5
In the clamp structure in which the magnetic disks 7 are stacked and fixed, a relative displacement between the magnetic disks 7 and the spindle hub 5, that is, a disk shift is required not to occur with respect to the guaranteed vibration and shock values. ing.

The disk shift after the product is completed causes wobbling of the data track, which adversely affects the positioning of the magnetic head 21. This is because it has an adverse effect or gives a user uncomfortable feeling, and adversely affects other peripheral devices. In addition, due to the application of the magnetic disk device to portable equipment, attention must be paid to disk shift for higher impact.

As described above, in order to solve the periodic strength of the clamping force due to the tightening force of the plurality of screws 10 in the circumferential direction, it is conceivable to provide only one screw 10 on the axis of the rotation center. . However, there are cases where it is better for the HDD design to use a plurality of screws 10 structurally like a fixed shaft type spindle motor, and it is necessary to perform clamping using the plurality of screws 10. .

Therefore, as shown in FIG. 11, a deep counterbore 12 is provided at a portion where the clamping force of the clamp disc 9 becomes small.
Are proposed to solve the periodic strength of the clamping force. When such a clamp disk 9 is used, the depth of the counterbore 12 is formed in a portion where the clamping force is reduced, and the thickness is reduced, so that the strength of the clamping force is weakened and the unevenness of the clamping force in the circumferential direction is improved. it can.

Further, since the clamping force is concentrated at a position close to the screw 10, the position where the head 10a of the screw presses the clamp disk 9 is preferably moved away from the disk pressing portion 9a (toward the inner peripheral side). As shown in FIG. 12, a clamp disk 9 provided with a step 11 has been proposed in order to realize the above-mentioned dimensions. This stage 11
The pitch of the hole 9b through which the screw 10 penetrates is substantially the same as the pitch circle diameter.
Is configured to be able to press the inner peripheral side.

When such a lamp disk 9 is used,
As shown in FIG. 13, the strength of the clamping force on the circumference of the disk pressing portion 9a is reduced, and the magnetic disk 7
Warpage and swell can be reduced.

As described above, the clamp structure of the magnetic disk drive is required to have a conflict that no disk shift occurs with respect to the guaranteed vibration and shock values and that the warpage and undulation of the disk 7 are reduced. In the first and second improvements, the strength of the clamping force at the disk pressing portion 9a is relaxed to reduce the warpage and undulation of the magnetic disk 7.

However, each improvement has the following problems. First, in the first example of the improved invention,
In general, the clamp disk 9 is made of aluminum or stainless steel, and as the processing method, press processing or machining using a lathe is used. Have been.

However, when machining, the deep counterbore 12 formed on the clamp disk 9 cannot be covered by lathe processing and must be cut by an end mill using a milling machine or the like. This leads to an increase in cost due to the introduction of processing equipment and an increase in processing time. Also, in press working, it is not impossible to make a shape if a relatively soft metal material is used, but it is necessary to respond to dimensional changes in other parts as a relief of volume with reduced thickness. And the cost increases. Further, the material properties, particularly the mechanical strength properties, of the thinned part are greatly changed, and it is difficult to reduce the strength of the deep sag 12 as intended and control the clamping force to make it uniform. is there.

Next, in a second improvement, the clamp disk 9 presses the magnetic disk 7 against the spindle hub 5 with a load that does not cause a disk shift, and is fixed so as to be integrally rotatable. .

The clamping force is applied to the fixed magnetic disk 7.
Although it greatly varies depending on the size of the sheet and the number of layers, a stress of about several tens kg / mm ² is generated in the clamp disk 9. The position where the maximum stress occurs is near the position where the head 10a of the screw presses the clamp disk 9. If the maximum stress reaches the plastic region of the material, the clamp disk 9 may sag and loosen during use and the worst disk may come off.

As described above, in the second improved example, the area where the screw head 10a comes into contact with the clamp disk 9 is greatly reduced, so that the clamp disk 9 and the screw head 10a for obtaining the same clamping force are obtained. Is significantly increased as compared with the conventional example shown in FIG.

In order to prevent the plastic deformation of the clamp disk 9, it is necessary to select a material having a higher proof stress. As a result, it becomes necessary to use an expensive material or to limit the processing method. And the processing time is prolonged.

Further, as shown in FIG. 14, the screw 10 may be mounted with an inclination, and the screw head 10a and the clamp disk 9 come into contact with each other on the outer peripheral side of the pitch circle diameter of the hole 9b. For this reason, the effect of relaxing the distribution of the clamping force in the disk pressing portion 9a by separating the portion where the screw 10 presses the clamp disk 9 from the disk pressing portion 9a as much as possible may not be sufficiently obtained. Therefore, the height of the step 11 provided on the clamp disk 9 needs to be sufficiently large, and the clamp disk 9 becomes large.

However, in a magnetic disk drive in which the standard of the outer diameter is set, it is necessary to make each component part as small as possible, and a configuration in which the part size becomes large is not preferable.

The present invention solves the above-mentioned problems, and reduces the distribution of the strength of the clamping force generated in the disk pressing portion even when the clamp disk is tightened using a plurality of screws, thereby reducing the warpage and undulation generated in the magnetic disk. It is another object of the present invention to provide a high-density magnetic disk device capable of ensuring stable flying of a magnetic head.

[0026]

The magnetic disk drive according to the present invention is characterized in that the transmission path of the clamping force is lengthened or areas of different strength are provided in the transmission path.

According to the present invention, it is possible to realize a disk device in which the clamping force in the disk pressing portion can be made uniform, the warpage and undulation of the magnetic disk can be reduced, and the stable floating of the magnetic head can be secured.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic disk drive according to a first aspect of the present invention comprises: a spindle hub having a disk mounted on an outer peripheral portion; and a spindle hub having an outer peripheral portion abutting on an inner peripheral portion of the disk. Clamp disc
A magnetic disk drive in which the clamp disk is pressed with a fastening force of a plurality of screws screwed to the spindle hub to fix the disk to the spindle hub,
The clamp disk is characterized in that a transmission path of a clamping force between an inner peripheral side tightened by the screw and an outer peripheral side pressing the disk is lengthened.

According to this configuration, the clamping force can be made uniform, and the warpage and undulation of the disk can be improved. 3. The disk drive according to claim 2, wherein the spindle hub has a disk mounted on an outer peripheral portion, a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk, and A magnetic disk drive in which the clamp disk is pressed to the spindle hub by pressing the clamp disk with a tightening force of a plurality of screws screwed to a hub, wherein the clamp disk has an inner peripheral side tightened with the screw and the inner disk. It is characterized in that a region having different strength is provided in a transmission path of the clamping force between the outer peripheral side pressing the disk and the outer peripheral side.

According to this configuration, the clamping force can be made uniform, and the warpage and undulation of the disk can be improved. A magnetic disk drive according to claim 3 of the present invention, wherein: a spindle hub having a disk mounted on an outer peripheral portion; a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk; A magnetic disk drive in which the clamp disk is pressed by the tightening force of a plurality of screws screwed into a spindle hub to fix the disk to the spindle hub, wherein the clamp disk has an inner peripheral side tightened by the screw. On the outer peripheral side that presses the disk, the inner peripheral side is elastically deformed by the tightening force of the screw so that the inner peripheral side approaches the spindle hub from a state of being inclined so as to be largely separated from the spindle hub, and the upper surface thereof is disc surface. Is characterized by being configured so as to approach in parallel.

According to this configuration, the transmission path of the clamping force becomes long, and even if the clamp disk is tightened using a plurality of screws, the strength of the clamping force generated in the disk pressing portion is reduced, and the warpage and undulation generated in the magnetic disk are reduced. Can,
Further, the clearance required for avoiding contact between the spindle hub and the clamp disk is constant at an arbitrary diameter, so that the axial dimension can be used effectively.

According to a fourth aspect of the present invention, in the magnetic disk drive according to the third aspect, a state in which the inner peripheral side is inclined to be more apart from the spindle hub than the outer peripheral side is provided over the entire circumference of the clamp disk. The cross-sectional shape along the radial direction is the same.

According to this configuration, a lathe can be used in the case of manufacturing by machining, and the productivity can be improved. A magnetic disk drive according to claim 5 of the present invention, wherein: a spindle hub having a disk mounted on an outer peripheral portion; a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk; A magnetic disk device in which the clamp disk is pressed by a plurality of screws screwed to a spindle hub and the disk is fixed to the spindle hub, wherein the clamp disk is
A thin portion or a thick portion is formed between an inner peripheral side tightened by the screw and an outer peripheral side pressing the disk.

According to this configuration, by forming regions having different mechanical strengths in the transmission path of the clamping force, the strength of the clamping force generated in the disk pressing portion can be reduced even when the clamp disk is tightened using a plurality of screws. Warpage and undulation generated in the magnetic disk can be reduced, and a magnetic disk device compatible with high density can be realized.

According to a sixth aspect of the present invention, in the magnetic disk drive according to the fifth aspect, the thin portion or the thick portion is provided over the entire circumference of the clamp disk, and the sectional shape of the clamp disk along the radial direction is the same. It is characterized by having.

A magnetic disk drive according to a seventh aspect of the present invention, wherein: a spindle hub having a disk mounted on an outer peripheral portion; and a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk. And a magnetic disk device in which the clamp disk is pressed by the tightening force of a plurality of screws screwed into the spindle hub to fix the disk to the spindle hub, wherein the clamp disk is tightened by the screw. A diaphragm shape is formed between a peripheral side and an outer peripheral side pressing the disk.

According to this configuration, the transmission path of the clamping force from the portion where the screw holds down the clamp disk to the disk pressing portion becomes longer, and even if the clamp disk is tightened using a plurality of screws, the clamping force generated in the disk pressing portion is obtained. The warpage and undulation generated on the magnetic disk can be reduced by reducing the strength of the magnetic disk, and a magnetic disk device corresponding to high density can be realized.

According to a magnetic disk drive of the present invention, the diaphragm shape is provided over the entire circumference of the clamp disk and the clamp disk has the same cross-sectional shape along the radial direction. Features.

According to this configuration, a lathe can be used in the case of manufacturing by machining, and the productivity can be improved. According to a ninth aspect of the present invention, in the magnetic disk drive according to the eighth aspect, the cross-sectional shape is an arc or a polygon.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. Note that components having the same configuration as in FIGS. 8 to 14 showing the above-described conventional example are denoted by the same reference numerals.

(Embodiment 1) FIGS. 1 to 3 show (Embodiment 1) of the present invention. As shown in FIG. 1, in the magnetic disk drive configured in the same manner as the conventional example, the clamp disk 9 before the screw 10 is tightened has an inner peripheral side 9c which is tightened by the screw 10 and an outer peripheral side which presses the disk 7. In the disc pushing portion 9a, the inner peripheral side 9c is inclined so as to be largely separated from the spindle hub 5.

The state where the inner peripheral side 9c is inclined so as to be farther away from the spindle hub 5 than the outer peripheral side disk pressing portion 9a is provided over the entire circumference of the clamp disk 9 as shown in FIG. The cross-sectional shape along the radial direction of the disk 9 is configured to be the same.

When the screw 10 is inserted into the hole 9b of the clamp disk 9 having such an inclined state and tightened to the spindle hub 5, the head 10a of the screw is largely separated from the spindle hub 5. Inclined hole 9b
The position where the load in the axial direction serving as the clamping force is applied to the inner peripheral side of the hole 9b first is on the inner peripheral side of the pitch circle diameter of the hole 9b.

Accordingly, since a clamping force is applied to the inner peripheral side of the clamp disk 9 in the above-described conventional example, a transmission path of the clamp force from the position where the head 10a of the screw presses the clamp disk 9 to the disk pressing portion 9a. And the distribution of the strength of the clamping force in the disk pressing portion 9a is relaxed, so that the warpage and undulation of the disk can be reduced.

The direction of inclination of the clamp disk 9 is such that a plurality of screws 1 extend from the rotation center of the shaft toward the outer diameter direction.
0 because it is inclined in the direction of action of the tightening force.
When the clamp disk 9 is tightened, the clamp disk 9 is elastically deformed in the direction of tightening the screw, and as shown on the side of the arrow A in FIG. It is elastically deformed by the tightening force, and its upper surface comes closer to being parallel to the surface of the disk 7.

At this time, if the inclination of the clamp disk 9 remains the same as before the screw 10 is tightened even after the screw 10 is tightened, the head 10a of the screw contacts the clamp disk 9 to reduce the clamping force. Hole 9 to load
In order to keep the inner circumference side of the pitch circle diameter of b, the screw head 1
The distance from the position where Oa presses the clamp disk 9 to the disk pressing portion 9a is kept large, and the effect of reducing the warpage and undulation of the magnetic disk 7 as described above is increased.

Next, the following two methods can be considered for managing the clamping force. One is a method of tightening until the clamp disk 9 hits the spindle hub 5, and the other is a method of defining the tightening torque of the screw 10.

However, in the former method, the clamping force is likely to vary greatly due to dimensional errors of the components, and if the screw 10 is further tightened in a state where the clamp disk 9 and the spindle hub 5 are in contact, the locality of the clamp disk 9 In general, a method of adjusting the torque with the tightening torque of the screw 10 is adopted because it may cause a sudden increase in stress and cause permanent deformation.

In this case, as a matter of course, it is necessary to design the clamp disc 9 so that the spindle hub 5 does not come into contact with the spindle hub 5 in a state where a clamping force is applied, and to consider variations in friction and the like due to tightening of the screw 10. .

After tightening the screw 10, the arrow B
As shown on the side, even if the inclined surface of the clamp disk 9 is substantially horizontal with the magnetic disk 7, the effect of reducing the warp and undulation of the magnetic disk 7 is obtained. Hub 5 and clamp disc 9
Since the margin of the gap required to avoid contact between the surfaces facing each other is constant at an arbitrary diameter, the axial dimension can be effectively used, which is more preferable.

Further, as described above, the state where the inner peripheral side 9c of the clamp disk 9 is inclined so as to be farther away from the spindle hub 5 than the outer disk press portion 9a is provided over the entire circumference of the clamp disk 9. If the cross-sectional shape along the radial direction is the same, a lathe can be used when the clamp disk 9 is manufactured by machining.
A highly productive processing method can be selected.

(Embodiment 2) FIGS. 4 and 5 show (Embodiment 2) of the present invention. In this (Embodiment 2),
The third embodiment is different from the first embodiment in that regions having different strengths are formed in the transmission path of the clamping force so that the clamping force of the clamp pressing portion 9a is made uniform.

As shown in FIG. 4, in the magnetic disk drive constructed in the same manner as in FIG.
A thick portion 15 or a thin portion 14 is provided between the inner peripheral side 9c receiving the tightening force of the screw 10 and the disk pressing portion 9a pressing the magnetic disk 7 so as to provide a region having different strength in the transmission path of the clamping force. Are formed.

The arrow C side shows an example in which a thick portion 15 is provided between the disc pressing portion 9a and the inner peripheral side 9c of the clamp disc 9, and the arrow D side shows an example in which a thin portion 14 is provided. is there.
The thick portion 15 has higher mechanical strength than other regions, and the thin portion 14 has lower mechanical strength than other regions.

As described above, if there are regions having different mechanical strengths in the transmission path from the inner peripheral side 9c where the head portion 10a of the screw presses the clamp disk 9 to the disk pressing portion 9a,
The distribution of the clamping force passing through this area is relaxed, so that the distribution of the clamping force in the circumferential direction can be made more uniform, and the warpage and undulation of the disc can be reduced.

Further, as shown in FIG.
Is provided over the entire circumference of the clamp disk 9 or, as shown in FIG. 5B, the thin portion 14 is provided over the entire circumference of the clamp disk 9 so that the cross-sectional shape along the radial direction is the same. As described above, a lathe can be used when the clamp disk 9 is manufactured by machining, so that a processing method with high productivity can be selected.

(Embodiment 3) FIGS. 6 and 7 show (Embodiment 3) of the present invention. In this (Embodiment 3),
The difference is that an aperture 16 is provided on the clamp disk 9 in order to lengthen the transmission path of the clamping force, but the other configuration is the same as in the above (Embodiment 1).

As shown in FIG. 6, in the magnetic disk drive constructed in the same manner as in FIG.
In order to lengthen the transmission path of the clamping force,
Stops 16a and 16b are formed between the inner peripheral side 9c receiving the tightening force and the disk pressing portion 9a pressing the magnetic disk 7.

The apertures 16a and 16b may have a convex aperture 16a formed outside the screw hole 9b as shown by the arrow E, and a concave aperture 16a outside the screw hole 9b as shown by the arrow F. The aperture 16b may be formed, and the shape is not particularly limited.

Even with the above-described configuration, the transmission path of the clamping force from the inner peripheral side 9c of the clamp disk 9 to the disk pressing portion 9a becomes longer, so that the distribution of the strength of the clamping force in the disk pressing portion 9a can be relaxed. Thus, the warpage and undulation of the disk can be reduced.

As shown in FIGS. 7A and 7B,
If the apertures 16a and 16b are provided over the entire circumference of the clamp disk 9 and are configured to have the same cross-sectional shape along the radial direction, a lathe can be used when the clamp disk 9 is manufactured by machining. Highly efficient processing method can be selected.

At this time, it is preferable that the cross-sectional shape of the apertures 16a and 16b in the radial direction is an arc or a polygon.

[0063]

As described above, according to the magnetic disk drive of the present invention, the transmission path of the clamping force between the inner peripheral side tightened by the screw of the clamp disk and the outer peripheral side pressing the disk is configured to be long. Alternatively, by providing regions having different strengths in the transmission path of the clamp force, even when the clamp disk is tightened using a plurality of screws, the strength of the clamp force generated in the disk pressing portion is reduced, and the magnetic disk 7 generates the force. Warpage and undulation can be reduced.

As a result, a stable floating of the magnetic head can be ensured, and a magnetic disk device compatible with high density can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a magnetic disk drive before fixing a clamp disk with screws according to (Embodiment 1) of the present invention;

FIG. 2 is a perspective view of the clamp disc of FIG. 1;

FIG. 3 is a sectional view of the magnetic disk drive of FIG. 1 after fixing a clamp disk with screws.

FIG. 4 is a cross-sectional view of a magnetic disk drive according to a second embodiment of the present invention.

5 is a perspective view of the clamp disc on the arrow C side in FIG. 4 and a perspective view of the clamp disc on the arrow D side in FIG. 4;

FIG. 6 is a sectional view of a magnetic disk drive according to a third embodiment of the present invention.

FIG. 7 is a perspective view of the clamp disk on the arrow E side in FIG. 6 and a perspective view of the clamp disk on the arrow F side.

FIG. 8 is a configuration diagram of a conventional magnetic disk drive.

FIG. 9 is a sectional view showing a clamp structure of a conventional magnetic disk drive.

FIG. 10 is a plan view of the clamp disc of FIG. 9;

FIG. 11 is a perspective view of a clamp disk of a first improved example in a conventional magnetic disk drive.

FIG. 12 is a perspective view of a clamp disk according to a second improvement in the conventional magnetic disk drive.

FIG. 13 is a sectional view of a magnetic disk drive using the clamp disk of FIG. 12;

FIG. 14 is a sectional view of a magnetic disk device for explaining a problem of the clamp disk of FIG. 12;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Spindle motor 3 Shaft 5 Spindle hub 7 Magnetic disk 9 Clamp disk 9a Disk pushing part 9b Hole 10 Screw 10a Screw head 14 Thin part 15 Thick part 16 Aperture

Claims (9)

[Claims] A spindle hub having a disk mounted on an outer peripheral portion thereof; a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk;
A magnetic disk drive in which the clamp disk is pressed by the tightening force of a plurality of screws screwed to the spindle hub and the disk is fixed to the spindle hub, wherein the clamp disk has an inner peripheral side tightened by the screw. A magnetic disk drive configured to lengthen a transmission path of a clamping force between the disk and an outer peripheral side pressing the disk. 2. A spindle hub having a disk mounted on an outer peripheral portion thereof, a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk,
A magnetic disk drive in which the clamp disk is pressed by the tightening force of a plurality of screws screwed to the spindle hub and the disk is fixed to the spindle hub, wherein the clamp disk has an inner peripheral side tightened by the screw. A magnetic disk drive configured to provide regions having different strengths in a transmission path of a clamping force between the disk and an outer peripheral side pressing the disk. 3. A spindle hub having a disk mounted on an outer peripheral portion thereof; a clamp disk set on the spindle hub such that an outer peripheral portion thereof is in contact with an inner peripheral portion of the disk;
A magnetic disk drive in which the clamp disk is pressed by the tightening force of a plurality of screws screwed to the spindle hub to fix the disk to the spindle hub, wherein the clamp disk is fastened by the screws on an inner peripheral side. On the outer peripheral side pressing the disk, the inner peripheral side is elastically deformed by the tightening force of the screw so that the inner peripheral side is closer to the spindle hub from a state inclined so as to be largely separated from the spindle hub, and the upper surface thereof is disc-shaped. A magnetic disk drive configured to approach parallel to a surface. 4. The clamp disk according to claim 3, wherein the inner peripheral side is inclined over the entire circumference of the clamp disk so as to be more distant from the spindle hub than the outer peripheral side, and the cross-sectional shape along the radial direction of the clamp disk is the same. Magnetic disk unit. 5. A spindle hub having a disk mounted on an outer peripheral portion thereof, a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk,
A magnetic disk drive in which the clamp disk is pressed by the tightening force of a plurality of screws screwed to the spindle hub and the disk is fixed to the spindle hub, wherein the clamp disk has an inner peripheral side tightened by the screw. A magnetic disk drive in which a thin portion or a thick portion is formed between the disk and the outer peripheral side pressing the disk. 6. The magnetic disk drive according to claim 5, wherein the thin portion or the thick portion is provided over the entire circumference of the clamp disk, and the clamp disk has the same cross-sectional shape along the radial direction. 7. A spindle hub having a disk mounted on an outer peripheral portion, a clamp disk set on the spindle hub such that an outer peripheral portion is in contact with an inner peripheral portion of the disk,
A magnetic disk drive in which the clamp disk is pressed by the tightening force of a plurality of screws screwed to the spindle hub and the disk is fixed to the spindle hub, wherein the clamp disk has an inner peripheral side tightened by the screw. A magnetic disk device in which a drawn shape is formed between the disk and an outer peripheral side pressing the disk. 8. The magnetic disk drive according to claim 7, wherein the aperture shape is provided over the entire circumference of the clamp disk, and the cross-sectional shape along the radial direction of the clamp disk is the same. 9. The magnetic disk drive according to claim 8, wherein said cross-sectional shape is an arc or a polygon.