JP2001028160A - Disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit information at high speed and to rotate even a disk high in unbalance at high speed without generating vibrations by structuring the transmission route of rotational power to be transmitted form the rotational power generating part of a disk to a disk loading part so as to have elasticity in the direction perpendiclar to a rotary axis. SOLUTION: Since a portion A consisting of a turntable 5a, a disk 7a and a clamper 6a is attached through an elastic material 4a to a portion B consisting of a spindle motor rotor part 2a and an elastic member supporting part 3a, the portion B has elasticity in the direction perpendiclar to the rotary axis. Besides, the partial geometrical center of the portion B is matched with a bearing center. On the other hand, the center-of-gravity position G of the portion A, is deviated from a geometrical center S by loading the unbalance disk 7a. In this case, when a spindle motor 22a is rotated to more increase a resonance frequency, the elastic material 4a is deformed and the portion A is rotated near the center-of-gravity G. Therefore, by adding the elastic material 4a, the unbalance vibration of the disk can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CD-ROM, a DV
The present invention relates to a disk device such as a D-ROM / RAM, MO, etc., which is interchangeable with a disk-shaped recording medium.

[0002]

2. Description of the Related Art In recent years, a method of obtaining a high transfer rate by increasing the rotational speed of a disk has been used in a disk device having a disk interchangeability. A CD-ROM drive is a representative example of a disk device that improves the transfer speed by rotating the disk at a high speed. CD-R
The problem in increasing the speed of the OM drive is described in, for example,
As shown in JP-A-92094, this is an unbalanced vibration that occurs when an unbalanced disc having a deviation between the geometric center of the disc and the position of the center of gravity is used. In order to suppress this unbalanced vibration, Japanese Patent Laid-Open No.
No. 94 proposes a ball balance mechanism using a ball.

[0003]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. 10-9209
When the unbalance is corrected by the ball balance mechanism disclosed in Japanese Patent Application Laid-Open No. 4 (1999) -1995, a correction error may occur. this is,
(1) Deviation between the ball raceway surface and the center of the disk (2) Non-uniform vibration of the mechanical unit (3) Inhibition of ball movement due to the ball being pressed against the raceway surface by centrifugal force. (1) relates to the accuracy of the part.
In the case of (2), on the principle of the ball balance mechanism, in order to arrange the ball at an appropriate position, the mechanical unit needs to swing properly in the rotation plane depending on the number of rotations of the disk.

However, in an actual mechanical unit, a moment is generated due to a difference in height between the disk arrangement portion and the seismic isolation leg arrangement portion, and the seismic isolation leg cannot be appropriately arranged due to a structural restriction of the mechanical unit. It may swing unevenly in the plane of rotation.

In the case of (3), especially when the ball is rotated at a high speed, the ball is pressed against the orbital surface for guiding the ball by centrifugal force, so that it is difficult to move in the orbital surface. In particular, when the ball moves to the unbalance correction position to some extent, the swing of the unit mechanism becomes small, so that the force for moving the ball to an appropriate position decreases, and the imbalance remains as a correction error.

The error which cannot be corrected by the ball balance mechanism remains as an imbalance, but the vibration caused by the imbalance is prevented from being transmitted to the outside by attaching the mechanical unit to the anti-shock leg. However, when the number of rotations of the disk increases, the force for generating the unbalanced vibration increases as the square, so that the unbalance correction error cannot be ignored.

[0007]

In order to solve the above-mentioned problems, a transmission path for transmitting a rotational force from a portion of the disk rotating means that generates a rotational force to a disk mounting portion has elasticity in a direction perpendicular to the rotation axis. Structure.

Further, a transmission path for transmitting the rotational force from a portion of the rotating means that generates the rotational force to the disk mounting portion is provided.
At least one connection is made via an elastic material.

The elastic material has an elastic coefficient of at least 1/10 or less with respect to other members constituting the rotational force transmission path.

The elastic modulus of the disk mounting portion in the direction perpendicular to the rotation axis is 30 N / mm or less.

The mass of a disk and a member arranged near the disk and rotating with the same rotation center as the disk is m, the disk rotation speed of the disk device is ω, and the elastic modulus in the direction perpendicular to the rotation axis of the disk mounting portion. Where ω> 2 × ωn, where ωn = SQR (k / m) (S
QR indicates the square root in parentheses).

There are at least two types of setting of the number of rotations of the disk of the disk device, ω1 and ω2. The mass of a disk and a member arranged near the disk and having the same rotation center as the disk and rotating is m, and the disk is mounted. When the elastic modulus in the direction perpendicular to the rotation axis of the part is k, ω1 <ωn <ω2, where ωn = SQR (k / m) (SQR indicates the square root in parentheses).

When the amount of deviation between the geometric center of the disk and the center of rotation during rotation of the disk is defined as the disk eccentricity, the maximum eccentricity emax that the disk device can tolerate and the maximum unbalance amount with respect to the geometric center of the disk. x,
Assuming that the mass of the disk and a member arranged near the disk and rotating with the same rotation center as the disk is m 2, the configuration satisfies m ≧ x / emax.

Further, a fixing means is provided for fixing the disk and a member arranged in the vicinity of the disk and having the same rotation center as the disk and rotating in the direction perpendicular to the rotation axis with respect to the rotating means. Further, a fixing means for fixing the geometric center of the disk and a member arranged near the disk and having the same rotation center as the disk and rotating at substantially the same position as the rotation center of the rotation means is provided.

The fixing means is fixed when the rotating means rotates at a low speed, and is released when the rotating means rotates at a high speed.

Further, the fixing means has a structure in which the position is displaced by centrifugal force generated by the rotation of the rotating means, thereby fixing / unfixing.

Further, the rotation means is provided with a restriction means for restricting displacement of the disk and a member arranged near the disk and having the same rotation center as the disk and rotating in the direction perpendicular to the rotation axis.

When the maximum eccentricity emax that can be tolerated by the disk drive is set to be equal to or less than emax, the maximum displacement in the direction perpendicular to the rotation axis of the disk and a member arranged near the disk and rotating with the same rotation center as the disk is rotated. The restricting means is arranged as follows.

Further, the disk imbalance correcting means is provided on a member which is arranged near the disk and rotates with the same rotation center as the disk.

The unbalance correcting means has a track surface centered on the center of rotation of the disk, and performs the unbalance correction using at least two or more spherical members moving on the track surface.

Further, there is provided a restricting means for enabling the disk mounting portion to move in the direction perpendicular to the rotation axis with respect to the rotating means, and for restricting displacement of the rotating means in the direction perpendicular to the rotation axis.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a side view of the spindle motor of the present invention. The spindle motor 22a is mounted on the mechanical unit 1a together with the head unit 21 and the like.
The spindle motor 22a is a spindle motor rotor unit 2
a, a spindle motor stator (not shown), a shaft 8a, an elastic material support 3a, an elastic material 4a, a turntable 5a, a clamper 6a, and the like. The disk 7a is placed on the turntable 5a and the clamper 6a
And the turntable 5a so as to sandwich the disk 7a. By rotating the spindle motor 22a in this state, the disk 7a is rotated, and signals are recorded or reproduced on the disk surface by the head unit 21.

In this embodiment, the rotational force is generated between the spindle motor rotor 2a and the spindle motor stator, and transmitted to the turntable 5a via the shaft 8a, the elastic support 3a, and the elastic material 4a. The turntable 5a, the disk 7a, and the clamper 6a are made of an elastic material 4a.
, So that they have elasticity in the direction perpendicular to the rotation axis, that is, in the radial direction of the disk 7a. Strictly speaking, the shaft 8a is also a component having elasticity because it is made of a stainless material or the like, but has sufficient rigidity with respect to the elastic material 4a, and is considered here as a rigid body.

Referring to FIG. 2, a description will be given of the vibration reducing operation of the present invention when the unbalanced disk is rotated. FIG.
(A) is a diagram for explaining the behavior when the disk 11 is rotated around bearings 13a and 13b via the shaft 12 when the disk 11 is unbalanced. Here, the symbols in FIG. 2A are O: bearing rotation center, S: geometric center of the disk 11 (position of the shaft 12 on the disk 11),
G: disk center of gravity position, r: distance between OSs, e: distance between SGs, ω: disk rotation speed, m: disk mass, k:
The elasticity of the shaft 12 is shown.

The behavior when this system is rotated is detailed in an introduction to mechanical vibration (WT Thomson, Maruzen Co., Ltd.) and the like, but as shown in FIG. 2B, the resonance point ωn = SQR
(K / m) (SQR indicates square root in parentheses)
The disk 11 tends to rotate around the center of gravity G as the disk rotation speed increases. When the disk 11 rotates around the center of gravity, the unbalanced vibration disappears, and the bearings 13a, 13b
Is only a restoring force generated from the amount of deflection of the shaft 12, that is, k × e. Thus, the shaft 1
When the disk 2 has elasticity in the direction perpendicular to the rotation axis, the disk 11 tries to rotate stably at a position close to the center of gravity G.

In the present invention, the vibration is reduced by utilizing the above effects, and the details will be described with reference to FIG. In the present invention, FIG.
Part A in (a) (turntable 5a, disk 7
a, the clamper 6a) is attached via the elastic material 4a, and thus has a structure having elasticity in the direction perpendicular to the rotation axis with respect to the portion B in FIG. 3 (a). B part is FIG.
As shown in (b), the geometric center of the component and the bearing center are manufactured so as to coincide with each other. On the other hand, because the unbalanced disk 7a is mounted on the portion A, the center of gravity G is shifted from the geometric center S of the portion A. Here, when the spindle motor 22a is rotated and the number of revolutions is made higher than the resonance frequency ωn, the elastic material 4a is deformed, and the portion A rotates at a position close to the center of gravity G.
By this operation, vibration due to disk imbalance can be suppressed.

The shaft 8a is a component having elasticity as described above. The spindle motor 22a has a structure in which the portion A is cantilevered by the shaft 8a. Here, when the shaft 8a is deformed and the disk 7a moves, the disk surface is inclined, and vibration occurs in a direction parallel to the rotation axis direction. Therefore, the elastic material 4a needs to be sufficiently flexible with respect to the shaft 8a so that the elastic material 4a can be sufficiently deformed before the shaft 8a is deformed.
Therefore, the rigidity of the elastic material 4a is 1/1 with respect to the shaft 8a.
It is desirable to set it to 0 or less.

The elasticity of the elastic material 4a is, for example, as follows: the disk rotation speed is 10,000 rpm;
Assuming that r and the resonance frequency are suppressed to の of the disk rotation speed, k becomes about 30 N / mm. Therefore, the elastic material 4
It is desirable that the elasticity k of a is suppressed to 30 N / mm or less.

FIG. 2B shows that as the disk rotation speed ω is larger than the resonance point ωn, the portion A in FIG. 3A rotates at a position closer to the center of gravity. Figure 2 actually
According to (b), when ω / ωn = 2, r / e = 1.33, which has a reduction effect of about 70%. Therefore, ω> 2 × ω
It is desirable to set m and k to be n.

By the way, like a CD-ROM drive,
There are systems that need to read two types of discs, a CD-ROM disc and a music CD disc. CD-RO
For the M disk, it is necessary to rotate the disk at a high speed in order to secure a high transfer rate. On the other hand, a music CD disk needs to be rotated at a standard speed (low speed). In this case, if the low-speed rotation speed is ω1 and the high-speed rotation speed is ω2, ω
There is no problem if 1 is sufficiently large with respect to ωn, but ω1
If there is no difference between ωn and ωn, resonance occurs and vibration increases. In the present invention, this can be handled by setting m and k so that ω1 <ωn <ω2.
When the number of rotations is ω1, the imbalance remains because the center of rotation is not at the center of the disk.

In the disk device of the present invention, the disk rotates near the center of gravity, and it is necessary to perform recording or reproduction on the disk in this state. The disk with a large unbalance has the geometric center S shown in FIG.
And the distance e between the center of gravity G and the center of gravity G increases. The head for recording or reproducing follows the track on the disk at a period synchronized with the rotation. However, when the distance e between the geometric center S and the center of gravity G increases, the head is created based on the geometric center of the disk. Since the recording track swings and rotates, it cannot follow. Here, the maximum deviation amount (hereinafter referred to as the maximum eccentric amount) that the head can follow even when the disk is rotated with a deviation from the geometric center S is emax, which is arranged on the elastic material shown in FIG. Assuming that the mass of the portion A having the rotation center near the center of gravity is m and the amount of unbalance of the disk is x, it is preferable to set m so as to satisfy m ≧ x / emax. There is a relationship of m × e = x between the unbalance amount x of the disk, the shift amount e between the geometric center and the center of gravity, and the mass m of the disk.

Then, the shift amount e between the geometric center and the center of gravity is
Is set to be equal to or less than the maximum eccentricity emax, the present invention can cope with the whirling of the disk. For example, the disk unbalance specification is 1gr
cm, the maximum eccentricity that the disk device can tolerate is ± 0.0
If it is set to 3 cm, the mass m of the portion A may be set to 33.4 gr or more. Here, since the disc is interchangeable, it is preferable to adjust and set the mass of the turntable and the clamper.

As described above, by disposing the elastic member in the rotational force transmission path of the spindle motor, it is possible to reduce the vibration caused by the imbalance of the disk. The arrangement of the elastic members may be the structures shown in FIGS. 4A to 4E in addition to the structure shown in FIG. 4 (a) to 4 (d) are cross-sectional views of the elastic material supporting portions 3b to 3e, the elastic materials 4b to 4e, and the turntables 5b to 5e for explaining the structure. FIG. 4A shows a structure in which the elastic material 4b is arranged on the outer periphery of the elastic material supporting portion 3b, and the turntable 5b is supported on the outer periphery of the elastic material 4b. FIG. 4B shows FIG.
Although the structure is almost the same as that of FIG. 7A, the upper surface of the elastic material supporting portion 3c is in contact with the lower surface of the turntable 5c, and supports the turntable 5c so as not to be displaced in a direction parallel to the rotation axis direction. FIG. 4C shows a structure in which the elastic material 4d is arranged at both positions of FIG. 4A and FIG. FIG. 4 (d)
Has a structure in which a plurality of elastic materials 4e are arranged.

The elastic material shown in FIGS. 4A to 4D is assumed to be, for example, rubber. However, the structure is not limited to this, and a spring 16 may be disposed on the shaft 14 as shown in FIG. 4E and connected to the turntable 15 so that the turntable 15 can be displaced in the direction perpendicular to the rotation axis. Further, a viscoelastic material may be used instead of the elastic material. In the embodiment, the rotation force generating portion of the spindle motor and the turntable are connected via an elastic material to realize a structure having elasticity in a direction perpendicular to the rotation axis. However, the present invention is not limited to this. Any structure may be used as long as it has elasticity and does not displace in the direction parallel to the rotation axis direction.

In the case where the spindle motor has a structure having elasticity in the direction perpendicular to the rotation axis, as shown in FIG. 2B, the amount of deflection becomes maximum when the disk rotation speed passes through the resonance point ωn. , May cause vibration. As means for preventing this, it is preferable to provide a turntable fixing means in the spindle motor as shown in FIG. In FIG. 5A, a turntable fixing arm 17 is arranged on the spindle motor rotor 2f. The spindle motor rotor 2f is manufactured so that the geometric center and the rotation center coincide with each other.
7 also rotates around the geometric center. The turntable fixing arm 17 is normally urged away from the turntable 5f by urging means such as a spring (not shown) as shown in FIG.

The coil 18 is arranged on the elastic member supporting portion 3f. In this embodiment, the turntable fixing arm 17 is made of a magnetic material, and when the coil 18 is energized, the turntable fixing arm 17 moves in the direction of the turntable 5f by magnetic force, and the geometric center of the turntable 5f is moved to the spindle motor rotor. It is fixed so as to substantially coincide with the geometric center of the portion 2f. Since the turntable fixing arm 17 fixes the turntable 5f while the coil 18 is energized, the turntable 5f rotates around the geometric center as the center of rotation.

Therefore, when the spindle motor 22f starts rotating, the turntable 5f is fixed to the spindle motor rotor 2f until the resonance point ωn is exceeded, and the whirling of the turntable 5f is suppressed. By releasing the turntable 5f at a rotation speed at which the rotation speed becomes smaller, it is possible to prevent generation of vibration at the resonance point ωn. Further, by using the present turntable fixing means, it is possible to cope with the case where the disk rotation speeds ω1 and ω2 are different from each other, such as a music CD and a CD-ROM, and ω1 is close to the resonance point ωn. That is, when the number of rotations of the disk is near ω1, the turntable fixing means is operated to suppress the whirling of the turntable 5f and perform recording or reproduction. At this time, since ω1 is at a low rotation, the vibration generated due to the imbalance of the disk is small and does not cause any problem.

Another embodiment of the turntable fixing means will be described with reference to FIG. FIG. 6A shows a turntable fixing arm 19 arranged on the spindle motor rotor 2g. The spindle motor rotor 2g is manufactured so that the geometric center and the rotation center coincide with each other, and the turntable fixing arm 19 also rotates around the geometric center. As shown in FIG. 6A, the turntable fixing arm 19 is moved to a position where the geometric center of the turntable 5g substantially coincides with the geometric center of the spindle motor rotor portion 2g by urging means such as a spring (not shown). It is biased to be fixed. At the time of low-speed rotation, the turntable fixing arm 19 fixes the turntable 5g, so that the geometric center of the turntable 5g rotates as the rotation center. When the rotation of the spindle motor 22g is increased, the centrifugal force applied to the turntable fixing arm 19 also increases, and starts to move in the outer peripheral direction when the centrifugal force becomes larger than the urging force of the turntable fixing arm 19. Therefore,
When the number of rotations exceeds a certain value, the turntable fixing arm 19
Is separated from the turntable 5g, and the turntable 5g can move in the direction perpendicular to the rotation axis. Therefore, the resonance point ωn
By adjusting the urging force of the turntable fixing arm 19 so that the turntable 5g is unlocked at the position where the disk rotation speed becomes higher, the turntable fixing means can be provided without disposing the coil.

By the way, a user sometimes attaches a sticker or the like to the label surface of the CD-ROM. Especially CD-R
In the case of a writable disc, the user often attaches a label sticker to discriminate the disc.
In this case, if the label sticking position is bad, an imbalance exceeding the specification occurs on the disc. If the spindle motor has elasticity, the disk will have a center of rotation near the center of gravity, so if an unbalanced disk exceeding the specifications is used, the deviation between the geometric center of the disk and the center of gravity will be the maximum eccentricity allowed by the disk device. Will be exceeded.

In order to prevent this, it is preferable to provide a regulating means for regulating the maximum displacement of the spindle motor in the direction perpendicular to the rotation axis. For example, if a disc having twice the imbalance is used, the distance between the geometric center of the disc and the center of gravity is also 2
Double. However, a displacement restricting means is provided to restrict the maximum displacement of the disk by restricting the displacement of the turntable to the maximum eccentricity emax permitted by the disk device, and the disk oscillates more than the maximum eccentric amount emax permitted by the disk device. Never. At this time, the unbalance remains on the disk, so vibration is not sufficiently suppressed.
By reducing the number of revolutions and suppressing the vibration generating force, it becomes possible to read even a disc whose imbalance is larger than the specification. The structure of the displacement restricting means can be realized by providing a turntable restricting portion 20 on the elastic material supporting portion 3h as shown in FIG. FIG. 7 is a cross-sectional view showing the elastic material support 3h, the elastic material 4h, and the turntable 5h for explaining the structure.

The present invention may be used in combination with another unbalance correction mechanism. FIG. 8 shows a spindle motor 22i in which the ball balance mechanism shown in the conventional example is disposed on the clamper 10. If the ball balance mechanism can correct the imbalance of, for example, 70%, the remaining 30% of the imbalance is corrected by the mechanism of the present invention. At this time, in the mechanism of the present invention, the remaining unbalance becomes 3/10, so that the distance between the geometric center of the disk and the rotation center becomes 3/10, and the reliability can be improved. FIG. 8 is a sectional view of the clamper 6i for explaining the structure.

Also, vibration can be reduced by a spindle motor which is capable of moving the turntable in the direction perpendicular to the rotation axis and which is provided with a regulating portion for regulating the moving distance of the turntable. This is a structure in which the elastic material 4h is removed from the spindle motor 22h shown in FIG. When the spindle motor is rotated, the turntable moves to the position of the regulating portion in the direction in which the center of gravity is shifted due to the shift of the center of gravity. Thereafter, when the number of rotations increases, the turntable, the disk, and the clamper rotate around their center of gravity, and coincide with the rotation center of the spindle motor rotor, thereby suppressing vibration.

[0043]

According to the above configuration, even a disk having a large unbalance can be rotated at a high speed without generating vibration, and a high-speed transfer of information becomes possible.

[Brief description of the drawings]

FIG. 1 is a side view of a spindle motor according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation principle of the present invention.

FIG. 3 is a diagram illustrating the operation of the present invention, which is one embodiment of the present invention.

FIG. 4 is a side sectional view showing an arrangement state of an elastic material according to one embodiment of the present invention.

FIG. 5 is a side sectional view of a spindle motor according to an embodiment of the present invention, in which fixing means is provided.

FIG. 6 is a side sectional view of a spindle motor according to an embodiment of the present invention, in which fixing means that operates by centrifugal force is provided.

FIG. 7 is a sectional side view of a spindle motor according to an embodiment of the present invention, in which displacement restricting means is provided.

FIG. 8 is a side sectional view illustrating a state in which a ball balance mechanism according to one embodiment of the present invention is used together.

[Explanation of symbols]

1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1
i: Mechanical unit, 2a, 2b, 2c, 2d, 2e, 2
f, 2g, 2h, 2i: spindle motor rotor, 3
a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i
... Elastic material support portions, 4a, 4b, 4c, 4d, 4e, 4
f, 4g, 4h, 4i ... elastic materials, 5a, 5b, 5c,
5d, 5e, 5f, 5g, 5h, 5i ... turntable, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6
h, 6i ... clamper, 7a, 7b, 7c, 7d, 7e,
7f, 7g, 7h, 7i: disks, 8a, 8b, 8
c, 8d, 8e, 8f, 8g, 8h, 8i ... shaft,
9 Objective lens 10 Unbalance correction ball 11
... disk, 12 ... disk support shaft, 13a, 13b ... bearing, 14 ... shaft, 15 ... turntable, 16 ... spring, 17 ... turntable fixing arm, 18 ... coil,
19: turntable fixing arm, 20: turntable regulating part, 21: head part, 22a, 22b, 22c,
22d, 22e, 22f, 22g, 22h, 22i ... spindle motors.

Claims (16)

[Claims] 1. An exchangeable disk-shaped recording medium,
A disk device having a mounting portion for the recording medium and rotating means for rotating the recording medium; and a recording and / or reproducing means for recording and / or reproducing on and from the recording medium; A transmission path for transmitting the rotational force from the portion that generates the force to the recording medium mounting portion is:
A disk device having a structure having elasticity in a direction perpendicular to a rotation axis, that is, in a radial direction of the recording medium when the recording medium is mounted on the recording medium mounting portion. 2. A disk drive according to claim 1, wherein at least one transmission path for transmitting a rotational force from a portion of said rotating means that generates a rotational force to said recording medium mounting portion.
A disk device, wherein the disk device is connected to at least two places via an elastic material. 3. A disk drive according to claim 2, wherein said elastic material has an elastic coefficient of at least 1/10 or less with respect to other members constituting said rotational force transmission path. 4. The disk device according to claim 1, wherein an elastic coefficient of the recording medium mounting portion in a direction perpendicular to a rotation axis is 30 N / mm or less. 5. The disk device according to claim 1, wherein the mass of the recording medium and a member arranged near the recording medium and rotating with the same rotation center as the recording medium is m,
Assuming that the recording medium rotation speed of the disk device is ω and the elastic modulus of the recording medium mounting portion in the direction perpendicular to the rotation axis is k, ω> 2 × ωn, where ωn = SQR (k / m) (S
(Where QR indicates a square root in parentheses). 6. The disk device according to claim 1, wherein said disk device has at least two types of setting of said recording medium rotation speed, ω1 and ω2, said recording medium being disposed near said recording medium and said recording medium. Assuming that the mass of a member rotating with the same rotation center as the medium is m and the elastic modulus of the recording medium mounting portion in the direction perpendicular to the rotation axis is k, ω1 <ω
n <ω2 where ωn = SQR (k / m) (SQR indicates a square root in parentheses). 7. The disk device according to claim 1, wherein a deviation amount between a geometric center of the recording medium and a rotation center during rotation of the recording medium is a disk eccentricity amount. The amount of eccentricity emax, the maximum unbalance amount x with respect to the geometric center of the recording medium, and the mass of the recording medium and a member arranged near the recording medium and rotating with the same center of rotation as the recording medium is defined as m. When
A disk device, wherein m ≧ x / emax. 8. The disk device according to claim 1, wherein the recording medium and a member disposed near the recording medium and rotating with the same rotation center as the recording medium are rotated perpendicular to the rotation means. A disk device comprising fixing means for fixing in a direction. 9. The disk drive according to claim 1, wherein a geometric center of the recording medium and a member arranged near the recording medium and rotating with the same rotation center as the recording medium is rotated by the rotating means. A disk device having a fixing means for fixing the same at a position substantially the same as the rotation center of the disk device. 10. The disk device according to claim 8, wherein said fixing means fixes when said rotating means rotates at a low speed, and releases said fixing when said rotating means rotates at a high speed. Disk device. 11. The disk device according to claim 8, wherein said fixing means displaces a position by a centrifugal force generated by rotation of said rotating means.
A disk device for performing fixing release. 12. The disk drive according to claim 1, wherein the recording medium and a member disposed near the recording medium and having the same rotation center as the recording medium and rotating with the same rotation center are restricted in a direction perpendicular to the rotation axis. A disk device, wherein a regulating means is provided on the rotating means. 13. The disk drive according to claim 12, wherein when the maximum eccentricity that can be tolerated by the disk drive is emax, the recording medium is arranged in the vicinity of the recording medium and rotated around the same rotation center as the recording medium. A disc drive, wherein the restricting means is arranged so that the maximum displacement of the member to be rotated in the direction perpendicular to the rotation axis is equal to or less than emax. 14. The disk device according to claim 1, wherein said recording medium imbalance correcting means is provided on a member which is arranged near said recording medium and rotates with the same rotation center as said recording medium. A disk device characterized by the above-mentioned. 15. A disk drive according to claim 14, wherein said unbalance correction means has a track surface centered on a rotation center of said recording medium, and at least two or more spherical surfaces moving on said track surface. A disk device wherein unbalance correction is performed by a member. 16. An exchangeable disk-shaped recording medium having a mounting portion for the recording medium, rotating means for rotating the recording medium, and recording and / or reproducing for recording and / or reproducing on the recording medium. And / or a disc device provided with a reproducing means, wherein the recording medium mounting portion is movable in a direction perpendicular to a rotation axis with respect to the rotating means, and a regulating means for regulating displacement of the rotating axis in a direction perpendicular to the rotating axis is provided to the rotating means. A disk device provided on a rotating means.