JP2001319444A - Spacer for hard disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spacer for hard disk which is simple in structure, little in reduction of performance due to temperature rise in rotation, and excellent in fitting precision, little in the surface shake of a substrate in rotation and capable of reducing an out-of-plane vibration effectively. SOLUTION: The spacer consists of an intermediate layer 2 and a surface part 3 insert-holding the layer 2 mutually in the state of layers to form a ring shape. The layer 2 is formed of a thermally stable resin member and is insert- held by the part 3 (3a and 3b) consisting of electrically conductive members. The electrically conductive members are selected from material of a young's modulus higher than that of the thermally stable resin and joined to each other through a joining part 4. The part 4 is jointed to the other one with its projecting part projecting at an outer peripheral part and an inner peripheral part from one of the part 3. The spacer is interposed between a disk and a spindle surrounding the spindle in a ring form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for a hard disk, and more particularly to a spacer for a hard disk which forms a part of a jig for clamping, for example, a magnetic disk.

[0002]

2. Description of the Related Art Conventionally, a high-density signal recording hard disk or the like used when reading and writing information on a disk rotates at an extremely high speed. Then, in order to shorten the access time of the disk, the rotational speed of the disk tends to be higher. At higher disk speeds, the disk typically vibrates violently, even with a slight imbalance in spindle position.

FIG. 6 shows a frequency component (hereinafter, referred to as a frequency response) included in the time history waveform with respect to the out-of-plane vibration of the disk. In the frequency response, as a vibration affecting reading and writing of data on the hard disk, there are a component synchronized with the disk rotation speed and a component not synchronized with the disk rotation speed. The component synchronized with the rotation speed is indicated by an arrow A in FIG. The component not synchronized with the rotation speed of the disk is indicated by arrow B. The component indicated by the arrow A can be solved by appropriately processing the data reading and writing signals even if the reading and writing are affected by vibration. The frequency component indicated by the arrow B cannot be corrected by signal processing even if the influence of vibration occurs. Therefore, the frequency component indicated by the arrow B is a frequency component in which a read / write error has occurred due to a change in the distance between the head and the surface of the disk, and its solution is a problem.

FIGS. 7A and 7B are vibration mode diagrams in a clamped state of a disk. FIG. 7A shows the (0, 1) mode, and FIG. 7B shows the (0, 2) mode. As shown in FIGS. 8 and 9, the elastic deformation of the disk main body and the deformation of the fixed portion that fixes the disk to the spindle vibrate together. The out-of-plane vibration is a frequency component generated when the (0, 1) mode and the (0, 2) mode, which have the greatest influence, resonate.

The (0, 1) mode is a deformation of the portion holding the disk, and the (0, 1) mode is an elastic deformation of the disk. And these (0,1) modes,
The vibration of the disk, which is caused by the resonance with the (0, 2) mode and is not synchronized with the rotation speed of the disk, is called “out-of-plane vibration”. One of the techniques for suppressing such out-of-plane vibration of a disk is disclosed in Japanese Patent Application Laid-Open No. H10-208366.

[0006] Japanese Patent Application Laid-Open No. Hei 10-208366 discloses that
A method for reducing vibration of a spindle during rotation by providing a dynamic vibration absorber on a spindle portion of a disk is disclosed. FIG. 8 shows a main part thereof.

FIG. 8 shows a configuration of a main part of a CD-ROM drive device provided with a dynamic vibration absorber. The base unit 20 is provided with a spindle motor 21, an optical reading system 22, and the like. The spindle motor 21 has a chucking table 24 on which a disk 23 is mounted, and a disk 2
A chucking yoke 25 is provided to be fitted in a circular hole 23a formed in the center portion of the nozzle 3.

The chucking section 26 is rotatably supported, and includes a chucking pulley 27, a vibration damping member 28,
It is composed of a magnet 29, a yoke plate 30, and the like.

The chucking pulley 27 formed of a metal material into a substantially dish-like shape has a disk portion 31 having a circular hole 27a formed in the center, and a portion near the outer peripheral edge thereof has a predetermined angle. By being bent, the peripheral wall 3
2 is formed, and an annular mounting wall 33 for mounting the magnet 29 and the yoke plate 30 is formed in the circular hole 27.
It is formed around the circular hole 27a with a diameter slightly larger than the diameter of a.

The vibration damping member 28 is formed in a ring shape, and a part thereof is received in an annular concave portion formed on a surface of the disk portion 31 facing the chucking table 24, and is formed on both surfaces. Using the adhesive tape 34, the disc 31
It is fixed to.

The disc-shaped magnet 29 is received in a recess formed by the mounting wall 33, and the magnet 29 is detached from the mounting wall 33 by mounting a yoke plate 30 having a locking portion thereon. Not to be.

Another example of suppressing out-of-plane vibration of a disk is disclosed in Japanese Patent Application Laid-Open No. 10-92094. This Japanese Patent Application Laid-Open No. H10-92
Japanese Unexamined Patent Publication No. 094 discloses a method in which an unbalance correction mechanism is provided on a spindle to reduce the unbalance that is a vibration source during rotation, thereby suppressing disk vibration. The main part is shown in FIG.

FIG. 9 is a sectional view of a CD-ROM device provided with an unbalance correction mechanism on a spindle. It shows a shunting state (a), a correction mode (b), and a rating mode (c). A disk 42 as a recording medium is inserted into the apparatus from the front panel 41 side by a tray. The unit mechanism 58 including the spindle motor 54, the pickup 48, and the drive system is retracted so as not to hinder the mounting of the disk 42.

A balance correction mechanism using a balance ball 47 is provided on a first clamp 59, and a second clamp 60 provided with a ball fixing mechanism that can move up and down coaxially is provided on the first clamp 59. In the case of a CD-ROM device, the rotation of the disk 42 is driven at a constant peripheral speed. Therefore, the rotation speed must be changed by performing acceleration / deceleration of the spindle motor 54 according to the position of the pickup 48. The unit mechanism 58 and the like are housed in the unit mechanism housing 50 and covered with a cover 49.

The unit mechanism 58 is supported from the chassis 51 by anti-vibration legs 53 made of soft rubber or a spring. The purpose of the anti-vibration legs 53 is to prevent the unbalanced vibration of the disk 42 from being transmitted to the outside of the apparatus and to prevent the vibration from the outside of the apparatus from being transmitted to the unit mechanism 58. In this example, the unit mechanism 58 moves upward from the retracted state (a), and the first clamp 59 is attracted by the magnet of the spindle motor 54 to fix the disk 42, and the disk 42 is rotatable. The first clamp 59 and the second clamp 60 are open, the balance ball 47 is in a freely movable state (correction mode b), and the unit mechanism 58 is further moved.
Is closed and the balance ball 47 is fixed (rated mode c).

[0016]

However, the configuration of the conventional apparatus has the following problems. JP-A-10-
In the method disclosed in Japanese Patent Publication No. 208366, the mechanism for reducing the vibration of the spindle is a dynamic vibration absorber. This dynamic vibration absorber has a problem that it needs to be designed in accordance with the drive rotation speed.

Further, there is also a case where the temperature rises due to the rotation of the disk, the characteristics of the vibration damping member 28 used in the dynamic vibration absorber thermally change, and the set frequency of the dynamic vibration absorber deviates from the rotation speed. It is possible that there is. In this case, the vibration damping effect may be deteriorated, and the vibration of the disk may increase.

Further, in the case of the technique disclosed in Japanese Patent Application Laid-Open No. Hei 10-92094, the unbalance correcting mechanism has a complicated balance structure for correcting the unbalance, and the dimensions of the spindle and the disk clamp are increased. There is a problem that there is a possibility.

By installing a resin member having a high vibration damping property between the substrate and the spindle, the vibration damping property is improved,
A method of reducing the vibration is also conceivable. However, since the resin having high vibration damping has a low Young's modulus, the mounting accuracy of the substrate is reduced, and the surface deviation of the substrate during rotation may be rather large. In addition, the resin often has no electric conductivity, so that static electricity cannot be released.

Accordingly, the present invention has been made in view of the above problems,
To provide a hard disk spacer that has a simple structure, has little performance degradation due to a rise in temperature during rotation, has excellent mounting accuracy, has little board runout during rotation, and can effectively reduce disk out-of-plane vibration. With the goal.

[0021]

Means for Solving the Problems In order to achieve the above-mentioned object, the following arrangement is provided. The hard disk spacer of the present invention is a hard disk spacer for fixing a disk to a spindle via a spacer, and includes an annularly formed intermediate layer, and an annularly formed front and back facing portion for sandwiching the intermediate layer. Comprising, the intermediate layer is made of a resin member mainly composed of a thermally stable resin, the front and back front and rear parts, the Young's modulus is higher than the intermediate layer, and is made of an electrically conductive member, The front and back surface mounting portions were configured to have a bonding portion that is partially bonded to each other via the intermediate layer and is conductive.

Further, it is preferable that at least one of the front and back mounting portions extends from the outer peripheral portion and the inner peripheral portion in the thickness direction of the intermediate layer and is joined to each other. Further, the joining portion may be at least one or more wall portions formed in a plate shape within the annular width dimension of the intermediate layer. The joint may be one or more pillars extending in the thickness direction in the intermediate layer.

In the spacer having the above-mentioned structure according to the present invention, a member mainly composed of a thermally stable resin is used as an intermediate layer, and a ring-shaped surface portion having a high Young's modulus sandwiches the intermediate layer and is partially joined to each other. In addition to the elastic deformation of the spindle and the disk and the vibration that the fixed part of the spindle deforms as a unit, the vibration damping function is provided between the spindle and the disk. The member maintains a constant shape even with vibration, and has little deflection. Since the joints of the front and back mounting portions are conductive, it is difficult to be charged with static electricity, to absorb surrounding dust, and to hardly give noise to the hard disk.

[0024] In the joint portion where the convex portions extending in the thickness direction are joined, the outer portion having a high Young's modulus covers the intermediate layer having a low Young's modulus with an outer peripheral portion and an inner peripheral portion. Further, in the joint portion provided with the plate-like wall portion, the front end of the wall is mechanically joined to the front mounting portion in a linear region at the front end of the wall. And in the joint part where the pillar part was provided,
The tip of the column part is mechanically joined to the front part in a scattered manner in the tip area.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. FIGS. 1A and 1B are a plan view and a cross-sectional view taken along line II ′ of a first embodiment, and FIGS. 2A and 2B are a plan view and II-II of a second embodiment. II 'sectional view, Fig. 3
(A) and (b) are plan views showing a third embodiment and II.
FIG. 4 is an exploded perspective view of a clamp portion for fixing the disk to the spindle, taken along the line I-III ′.

The spacer according to the embodiment of the present invention is:
In a hard disk drive, it is interposed between a disk and a spindle. The disk may be a built-in hard disk or an external hard disk. As shown in FIGS. 1 and 4, the spindle 12 is
a and the holding member 12b. Projecting member 1
In 2a, a large-diameter disc-shaped substrate 13 and a small-diameter cylindrical body 14 are overlapped and joined in a coaxial circle, and the central axis is thin and a hollow tube 15 is formed.

The holding member 12b is formed in a disk shape having a diameter larger than the diameter of the cylindrical body 14 on the protruding member 12a side. A circular portion 16 having the same diameter as the tubular cavity 15 on the protruding member 12a side is hollowed out from the central axis of the suppressing member 12b. As shown in FIGS. 4 and 1 (a) and 1 (b), the spacer 1 has a ring shape having the same inner diameter as the cylindrical body 14 so that the spacer 1 can be mounted on the outer periphery of the cylindrical body 14 on the protruding member 12a side. Is formed. This ring-shaped spacer 1 has an intermediate layer 2
And the front portion 3 (front and rear front portions 3a and 3b) sandwiching the intermediate layer 2 in a layered manner, substantially forming three layers.

The intermediate layer 2 is composed of a member mainly composed of a thermally stable resin. In this specification, a thermally stable resin has a glass transition point of 80 ° C. or higher and an environmental temperature of 80 ° C.
It is a resin material that maintains toughness at a temperature of less than ° C. Then, it may be a thermosetting resin or a thermoplastic resin.

Examples of the thermosetting resin used in the intermediate layer 2 include polyester resins, and examples of the thermoplastic resin include polyolefin resins.
These may be used alone or in combination. In particular, polyester resins are preferred in consideration of heat resistance, weather resistance, and the like.

The intermediate layer 2 is formed in a ring shape. The inner diameter of the intermediate layer 2 is wider than the spindle rotation axis so that it can be inserted into the spindle 12 that rotates the disk 11. Outer diameter is 30m in consideration of interference with the drive read head
m or less is good. The mid layer 2 has a Young's modulus of 5 × 10 ⁶ or more.
It is preferably 1 × 10 ⁷ N / m ² . If it is less than 5 × 10 ⁶ or more than 1 × 10 ⁷ N / m ² , the vibration damping performance is undesirably reduced.

On the other hand, the front mounting portion 3 has a front mounting portion 3a on the front side and a front mounting portion 3b on the back side, and is made of an electrically conductive member having a higher Young's modulus than the intermediate layer 2, and is made of metal, conductive ceramic, conductive resin, or the like. Regardless.

The metal may be an alloy or a pure metal.
Examples of the metal include an aluminum alloy material. Examples of the ceramic material include silicon-based ceramics. In consideration of thermal expansion and the like, an aluminum material is preferable.

It is preferable that the front and back cover portions 3a and 3b have a Young's modulus of 1 × 10 ¹⁰ N / m ² or more. 1 × 10
^If it is less than ¹⁰ N / m ² , the vibration damping performance is undesirably reduced. The front and rear mounting portions 3a and 3b are ring-shaped, have an inner diameter that can be inserted into the spindle rotation shaft without any gap, and have a sufficient annular width to cover the intermediate layer 2 with the front or back.

The front and back cover portions 3a, 3b and the intermediate layer 2 may be joined via an adhesive or may be joined by thermocompression bonding. Examples of the bonding adhesive include an epoxy-based adhesive.

As shown in FIGS. 1 (a) and 1 (b),
Are partially joined to each other on the front and back sides via the joint 4. The joining portion 4 forms a convex portion in which at least one of the front and rear mounting portions extends from the outer peripheral portion and the inner peripheral portion in the thickness direction of the intermediate layer 2 and is joined to each other. Joint 4
At the outer peripheral edge is projected from the front facing portion 3a to the rear facing portion 3b in a ring shape and joined, and conversely, at the inner peripheral edge, is projected from the back facing portion 3b to the front facing portion 3a in a ring shape. To cover the outer peripheral edge and the inner peripheral edge of the intermediate layer.

The joint 4 is formed of an electrically conductive member. The joining portion 4 may be formed integrally with the front and rear mounting portions 3a and 3b, or may be formed as separate bodies. The joining portion 4 may be made of the same material as the electrically conductive members constituting the front and back mounting portions 3a and 3b, or may be made of a different material. However, from the viewpoints of joining strength, easiness of molding, and the like, it is preferable to use a conductive member made of the same material as the electric conductive member constituting the front and back front mounting portions 3a and 3b.

It is to be noted that the joining portion 4 may protrude from the same one of the outer peripheral edge and the inner peripheral edge from the same one to the other side. Further, it is not always necessary that the convex portion serving as the joining portion 4 protrudes over the entire outer peripheral edge or the entire inner peripheral edge.
It may protrude intermittently, that is, in the form of teeth of a comb. In addition, one of the front and rear mounting portions 3a and 3b may alternately and intermittently protrude from each other so that the front and rear mounting portions 3a and 3b mesh with each other.

In order to join the outer covering portions 3a and 3b holding the intermediate layer 2 equally and with appropriate strength, the entire periphery of the outer peripheral edge and the inner peripheral edge of the intermediate layer 2 is a convex portion as the joining portion 4. It is good to cover with. The wall thickness of the convex part from which the outer peripheral edge and the inner peripheral edge protrude
0.5 to 1 mm is preferable. If it is 0.5 mm or less, it may be difficult to obtain sufficient strength at the joint. If it exceeds 1 mm, the vibration damping performance is undesirably reduced.

Next, a second embodiment will be described with reference to FIG. 1 and 4 are denoted by the same reference numerals and description thereof will be omitted. The joining portion 4 may be provided with a plate-shaped wall portion 4A within the annular width dimension of the intermediate layer 2, and joined via the wall portion 4A. For example, they are provided radially with the center of the ring as the center point, traverse the middle layer 2 between the inner circumference and the outer circumference, and partition the middle layer 2 by the thickness width of the middle layer 2. You may.

The direction of the wall 4A does not necessarily have to be radial. It may extend in any direction in the intermediate layer 2.
The shape of the wall portion 4A is not limited to a flat plate shape, and may be, for example, curved in a circumferential direction.

At least one or more wall portions 4A may be provided. However, in order for the front and back surface mounting portions 3a and 3b sandwiching the intermediate layer 2 to be uniformly joined with an appropriate strength, the center of the ring must be at the center point. It is preferable to provide three to four radially equiangular points.

The wall thickness is preferably 0.5 to 1 mm. 0.5
If it is less than mm, it may be difficult to obtain sufficient strength at the joint. If it exceeds 1 mm, the vibration damping performance decreases, which is not preferable. The wall portion 4A may be protruded from at least one of the front and rear mounting portions 3a and 3b in advance, and may be joined when combined with the other. May be joined.

Next, a third embodiment will be described with reference to FIG. 1 and 4 are denoted by the same reference numerals, and description thereof is omitted. The joint 4 may be formed of one or more pillars 4 </ b> B extending in the thickness direction in the intermediate layer 2.
For example, in the intermediate layer 2, circumferential annular regions are interspersed, for example, at equal intervals between the inner circumference and the outer circumference, each extends in the thickness direction of the intermediate layer 2, penetrates the intermediate layer 2, and the front and back front and rear mounting portions 3
a, 3b.

The column portion 4B only needs to extend in the thickness direction in the intermediate layer 2. The invention is not necessarily limited to the case of being scattered in the circumferential ring. They may be randomly scattered, or may be linearly scattered in a plurality of parallel line regions. There may be at least one pillar portion 4B. However, in order to join the front and back surface mounting portions 3a and 3b sandwiching the intermediate layer 2 uniformly and with appropriate strength, the pillar portion 4B may be formed around the center of the annular body. It is preferable that about 8 to 16 lines are scattered in a circular area in the circumferential direction at an angle. 8 to 1
When about six dots are scattered, the thickness of the pillar part 4B is 0.5 to 1
mm is better. If it is less than 0.5 mm, it may be difficult to obtain sufficient strength at the joint. On the other hand, if it exceeds 1 mm, the vibration damping property is undesirably reduced.

The pillar 4b may be protruded from at least one of the front and back mounting portions 3a and 3b, and may be combined with the other and joined together. When combined, they may be joined. In addition, the above-mentioned joint shown in FIGS.
For example, two or more may be used in combination. The joints 4 (4a, 4b) have a sufficient area so as not to deflect against vertical tightening load at the time of mounting, and it is convenient if the area does not impair the vibration damping performance. The term “joining” as used herein means not only metallurgical welding, bonding with an adhesive, or the like, but also simple contact, fitting, etc., as long as electrical contact can be ensured by contacting the front and back front and rear mounting parts 3a, 3b. It also includes good conditions.

[0046]

Next, embodiments of the present invention will be described. This embodiment is not limited to this embodiment. Hereinafter, Example 1 of the spacer 1 will be described. Embodiment 1 is shown in FIG.
(A) The configuration of the spacer already described with reference to (b), wherein the intermediate layer 2 is formed of a ring-shaped polyester resin and has a thickness of 150 μm, and the intermediate layer 2 is made of an aluminum front cover 3 (3a, 3a). By 3b), it is sandwiched in layers from the front and back. The front and back front mounting portions 3a and 3b are connected to each other via the bonding portion 4 and are conductive. The joint 4 has a ring-shaped convex portion having a width of 1 mm.

The second embodiment of the spacer 1 is shown in FIG.
The configuration described above is based on (a) and (b). And the wall part 4A which is a joining part is formed of the aluminum partition wall. The wall portion 4A is provided radially at an opening of 120 degrees with the center of the ring as the center point, and partitions the middle layer 2 made of a thermally stable resin in the thickness direction. The thickness width of the wall portion 4 is approximately 1 mm, and the end of the wall portion is joined to the front mounting portion. Others are the same as the first embodiment.

Further, the third embodiment of the spacer is shown in FIG.
The configuration has already been described based on (b). And the pillar part 4B which is a joining part is formed of the aluminum pillar material. The column members 4B are scattered at equal intervals in the circumferential direction at a pitch of 22.5 degrees in the intermediate layer 2, each extending in the thickness direction of the intermediate layer 2, and penetrating the intermediate layer 2. The front end of the pillar 4B is joined to the aluminum outer cover 3 (3a, 3b). Others are the same as the first embodiment.

The above spacers shown in Examples 1 to 3
As shown in FIG. 4, it is inserted into the cylindrical body 14 of the protruding member 12a of the spindle in a ring shape, and used by being interposed between the disk 11 and the spindle 12. Even if the rotating disk 11 vibrates due to a slight deviation of the cylindrical body 14 corresponding to the rotation axis of the spindle 12, the thermally stable resin member having a low Young's modulus absorbs the vibration.

The above spacers shown in Examples 1 to 3 are compared with other examples. 6 shows vibration characteristics when a spacer is mounted between the disk and the disk. 3.5inch, 0.8m thick
5 shows vibration characteristics when an Al disk made of m is clamped to a spindle of a hard disk via a spacer.
As a comparison, a case where the disk is directly clamped by a conventional Al spacer and a ceramic spacer is shown. Table 1
2 shows the measurement results of the damping ratio when the disk 1 is clamped on the spindle 2.

[0051]

[Table 1]

FIG. 5A shows a conceptual diagram of the measurement of the attenuation ratio.
A transfer function is obtained by hitting a point on the disk 11 with a hammer 61 with a load cell. This transfer function is a transfer function between the vibration frequency response outside the disk surface and the frequency response of the striking excitation force. The out-of-plane vibration frequency response is obtained by hitting a point on the disk surface with a hammer 61 with a load cell, measuring the obtained out-of-plane vibration with a laser Doppler velocimeter 62, and performing frequency analysis on the obtained time history waveform. I get it. The frequency response of the striking excitation force is obtained by frequency-analyzing the time history waveform of the excitation force at the time of striking with the hammer.

In the frequency response of the transfer function, assuming that the frequencies at the point where the 3 dB amplitude falls with respect to the resonance peak that is the natural frequency fN are f1 and f2, the relationship between the damping ratio ξ and these frequencies is as follows: There is. ξ = (f1−f2) / (2 * fN) (1)

From the frequency response of the transfer function, the damping ratio is obtained by using equation (1). Table 1 shows the measurement results in each case. In each of the spacers of Examples 1 to 3, A
In the case of 1 and ceramic spacers, the damping ratio is large, indicating that the effect of reducing out-of-plane vibration is high.

Next, with respect to the out-of-plane amplitude at the time of rotation of the disk, a comparison was made between the case where the spacers of Examples 1 to 3 were used and the case where Al or ceramic spacers were used.

FIG. 5B shows a conceptual diagram of the measurement. 3.5i
An Al disk 11 having an nch thickness of 0.8 mm was fixed to a hard disk clamp portion via a spacer 1, and out-of-plane vibration of the disk when the disk 11 was rotating was measured by a laser Doppler velocimeter 62. Disk 11
Frequency analysis of the time history response of the out-of-plane vibration of the disk, and shows the maximum amplitude of the vibration component in which the disk 11 elastically deforms and the fixed part of the spindle 2 deform integrally when the disk rotation speed is 10,000 rpm. It is shown in FIG.

Next, Table 2 shows the evaluation results of the disk surface deflection during rotation with respect to the mounting accuracy as characteristics relating to temperature rise. In the evaluation, Δ indicates that there is no problem in the disk surface deviation amount during rotation with respect to disk access.

[0058]

[Table 2]

From the above results, it can be said that the above embodiment is effective as a performance that achieves both vibration damping and mounting accuracy.

[0060]

The spacer for a hard disk of the present invention is
With the above-mentioned configuration, the structure is simple, the performance decrease due to the temperature rise during rotation is small, the mounting accuracy is excellent, the board runout is small during rotation, and the disk out-of-plane vibration is effectively reduced. A hard disk spacer that can be reduced can be provided.

Since shear deformation for providing vibration damping is possible, the elastic deformation of the spindle and the disk and the vibration in which the fixed portion of the spindle is integrally deformed are
Vibration damping can be added. The vibration amplitude value during rotation can also be reduced.

Since the electrically conductive members are partially in contact with each other, the thermosetting resin having a low Young's modulus does not bend, and the runout can be reduced. In addition, it is also possible to discharge static electricity, it is hard to get dirty, and it is hard to hinder the function of the disk. It is possible to increase the damping property without impairing the accuracy in mounting the clamped disk, and even when rotating at a high speed, the vibration amplitude is small, and the data reading and writing functions are not impaired.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are a plan view showing a first embodiment of a hard disk spacer according to the present invention, and FIGS.
It is an I 'line sectional view.

FIGS. 2A and 2B are a plan view and II-I showing a second embodiment of a hard disk spacer according to the present invention.
FIG. 3 is a sectional view taken along line I ′.

FIGS. 3 (a) and 3 (b) are a plan view and III-I showing a third embodiment of a hard disk spacer according to the present invention.
FIG. 2 is a sectional view taken along line II ′.

FIG. 4 is an exploded perspective view of a clamp part for fixing a disk of the spacer for a hard disk to a spindle according to the present invention.

5A and 5B are a conceptual diagram of measurement of an attenuation ratio and a conceptual diagram of measurement of out-of-plane amplitude.

FIG. 6 is a diagram illustrating frequency components included in a time history waveform.

FIGS. 7A and 7B are schematic diagrams showing a vibration mode diagram (0, 1) mode in a disk clamped state and a vibration mode diagram (0, 2) mode in a disk clamped state.

FIG. 8 is a diagram showing a configuration of a main part of a CD-ROM drive device provided with a conventional dynamic vibration absorber.

FIGS. 9A, 9B and 9C are cross-sectional views of a conventional CD-ROM device provided with an unbalance correction mechanism on a spindle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spacer 2 Intermediate layer 3 (3a, 3b) Surface mounting part 4 (4A4B) Joint part (convex part, wall part, pillar part) 11 Disk 12 (12a, 12b) Spindle 13 Substrate 14 Columnar body 15 Hollow

Claims (4)

[Claims] 1. A hard disk spacer for fixing a disk to a spindle via a spacer, comprising a ring-shaped intermediate layer, and ring-shaped front and back mounting portions for sandwiching the intermediate layer. The intermediate layer is composed of a resin member mainly composed of a thermally stable resin, and the front and back surface mounting portions have a higher Young's modulus than the intermediate layer,
A hard disk spacer comprising an electrically conductive member, wherein the front and rear facing portions have a joining portion that is partially joined to each other through the intermediate layer to conduct electricity. 2. The joining portion, wherein at least one of the front and rear mounting portions is a convex portion extending from an outer peripheral portion and an inner peripheral portion in a thickness direction of the intermediate layer and joined to each other. The hard disk spacer according to claim 1. 3. The spacer for a hard disk according to claim 1, wherein the joint is at least one wall formed in a plate shape within the annular width of the intermediate layer. 4. The hard disk spacer according to claim 1, wherein the joint is one or more pillars extending in the thickness direction in the intermediate layer.