JP2001101823A - Disk-like recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make firmly holdable a disk substrate of an approximately disk shape having a center hole by means of a center core that is engaged with the center hole and an elastic displacement member by reducing the deformation of the disk substrate significantly when the core center and the elastic displacement member hold the disk substrate between them while they are pressing the disk substrate in its depth direction. SOLUTION: This recording medium includes a disk substrate of an approximately disk shape having a center hole, a center core which is engaged with the center hole of the disk substrate and an elastic displacement member which presses the disk substrate in the depth direction of the substrate and also holds this substrate with the center core. The disk substrate has a projecting part of an approximately circular shape formed around its center hole and on its main surface set at the side of the elastic displacement member, and this projecting part abut on the elastic displacement member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk-shaped recording medium in which a substantially disk-shaped disk substrate is sandwiched between a center core and an elastic displacement member.

[0002]

2. Description of the Related Art Disc-shaped recording media are widely used not only for recording information on personal computers and the like, but also as recording media for recording image information, music information, and the like.

[0003] In order to increase the capacity and improve the reliability of the disk-shaped recording medium, even if the recording medium adopts any recording / reproducing method such as magnetic recording, magneto-optical recording, optical recording, etc. Improvement of the flatness of the surface is desired. For example, in the case of a magnetic disk in which signals are recorded and / or reproduced using a floating magnetic head or a contact or pseudo-contact magnetic head, particularly a hard disk medium used in a personal computer or the like, the flatness of the surface of the medium is high. Has become an important technical issue.

For example, a hard disk medium 100
Is, as shown in FIG. 10 and FIG.
1, a center core 102 that engages with the disk substrate 101, and a spring 103 that engages with the center core 102 and clamps the disk substrate 101 while pressing it in the thickness direction.

The disk substrate 101 has a substantially disk shape.
A center hole 10 that engages with the center core 102
4 are drilled. In addition, a magnetic thin film layer is formed on the main surface of the disk substrate 101, and a portion where the magnetic thin film layer is formed is a signal recording area where a signal is actually written or read.

The center core 102 has a substantially disk shape as a whole, and has a flange portion 105 on which the disk substrate 101 is placed when the disk substrate 101 is engaged with the outer peripheral end thereof. In the center of the center core 102, an insertion hole 106, which is inserted into the rotation shaft of the spindle motor when mounted on the hard disk drive, is formed so as to penetrate in the thickness direction.

The spring 103 is made of an elastically displaceable member having a substantially disk shape as a whole, and has a convex pressing portion 107 formed in a substantially annular shape at an outer peripheral end thereof. A center hole 108 for engaging with the center core 102 is formed in the center of the spring 103.

In the hard disk medium 100, a spring 103 sandwiches the center of the disk substrate 101 together with the center core 102, and is fixed by screws, caulking, spot welding, or the like, and holds the disk substrate 101. At this time, the hard disk medium 10
At 0, the pressing portion 107 of the spring 103 presses the disk substrate 101 in the thickness direction while abutting on the disk substrate 101 to urge the disk substrate 101 toward the flange portion 105 of the center core 102.

The hard disk medium 100 configured as described above is mounted on the hard disk drive by inserting the insertion hole 106 of the center core 102 with the rotating shaft of the spindle motor of the hard disk drive. In the hard disk drive, when the hard disk medium 100 is rotationally driven by the spindle motor, recording and reproduction of signals are performed while the magnetic head floats on the signal recording surface of the hard disk medium 100.

[0010]

By the way, in the above-mentioned hard disk medium 100, in order to improve the flatness of the surface of the medium, not only the surface of the disk substrate 101 is made flat without irregularities, but also the hard disk medium 100 is hardened. The accuracy and the flatness of the components constituting are improved.

In the hard disk drive, it is necessary to rotate the hard disk medium 100 at high speed and high precision. In order to maintain stability and accuracy during rotation of the hard disk medium 100, the disk substrate 1 must be rotated.
01 must be held by the center core 102 and the spring 103 with a sufficient clamping force.

However, in the above-described hard disk medium 100, when the center core 102 and the spring 103 sandwich the center portion of the disk substrate 101, the entire hard disk medium 100 may be deformed.

That is, the hard disk medium 1
12, the contact portion between the disk substrate 101 and the center core 102 due to a difference in rigidity between the disk substrate 101 and the center core 102 and the spring 103 or a difference in linear expansion coefficient with respect to a change in ambient temperature. A is shifted between A and the contact portion B between the disk substrate 101 and the spring 103 in the directions indicated by arrows A ₁ and B ₁ in the figure. Then, the holding forces generated at these contact portions A and B, so-called clamping forces A ₂ and B ₂ act as moment forces in the radial section of the disk substrate 101, and the entire disk substrate 101 is indicated by an arrow C in the figure. It will be deformed in the direction.

Therefore, such a conventional disk-shaped recording medium has a problem that the flatness of the surface of the medium is greatly reduced due to deformation of the disk substrate 101.

The deformation of the disk substrate 101 shows the strongest deformation in the radial direction passing through the clamp portion of the center core 102 and the spring 103, and the amount of deformation decreases as the distance from the radial direction portion increases in the circumferential direction.
For this reason, in the conventional disk-shaped recording medium, the entire disk substrate 101 is deformed in an umbrella shape, and at the same time, the wave-shaped deformation is generated in the circumferential direction. Such deformation not only hinders the narrowing of the distance between the signal recording surface of the hard disk medium 100 and the magnetic head described above, but also causes a runout during high-speed rotation.

Accordingly, the present invention has been proposed in view of such a conventional situation, and a substantially disk-shaped disk substrate having a center hole is provided together with a center core engaging with the center hole and an elastic displacement member. When holding the disk substrate while pressing it in the thickness direction, the deformation of the disk substrate is greatly reduced, and a disk-shaped recording medium capable of holding the disk substrate more firmly by the center core and the elastic displacement member. The purpose is to provide.

[0017]

According to the present invention, there is provided a disk-shaped recording medium according to the present invention, comprising: a substantially disk-shaped disk substrate having a center hole; a center core engaged with the center hole of the disk substrate; An elastic displacement member for holding the disk substrate together with the core while pressing the disk substrate in the thickness direction. The disk substrate has a substantially annular convex portion centered on the center hole on the main surface on the elastic displacement member side, and the convex portion is in contact with the elastic displacement member.

As described above, the disk-shaped recording medium according to the present invention has a substantially annular convex portion centered on the center hole on the main surface of the disk substrate on the elastic displacement member side. Is in contact with the elastic displacement member, the displacement of the contact portion between the center core and the elastic displacement member with respect to the disk substrate can be suppressed. Thus, the moment force in the radial cross section of the disk substrate can be reduced, and the entire disk-shaped recording medium can be prevented from being deformed.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, the dimensions of each part are shown at a ratio different from the actual value in order to clarify the structure.

Disc-shaped recording medium 1 to which the present invention is applied
As shown in FIG. 1 and FIG. 2, a hard disk medium is mounted on a hard disk drive and records and / or reproduces signals while a magnetic head flies at minute intervals.

The disk-shaped recording medium 1 includes a disk substrate 2 and a center core 3 that engages with the disk substrate 2.
And a spring 4 that engages with the center core 3 and clamps the disk substrate 2 while pressing the disk substrate 2 in the thickness direction.

The disc substrate 2 is formed by injection molding a resin material such as polycarbonate, for example, so that the center hole 5 is formed.
It is formed into a substantially disk shape having On at least one main surface of the spring 4 of the disk substrate 2, a magnetic thin film layer is formed by depositing a magnetic material, and the portion where the magnetic thin film layer is formed actually This is a signal recording area 2a where writing and reading are performed.

On the main surface of the disk substrate 2 on the side in contact with the spring 4, a substantially annular convex portion 6 centered on the center hole 5 is located on the inner peripheral side of the signal recording area 2a. Is formed. The substantially annular convex portion 6 centered on the center hole 5 comes into contact with a pressing portion of the spring 4 described in detail below. It should be noted that such a convex portion is not formed on the main surface of the disk substrate 2 on the side in contact with the center core 3, and is a flat surface.

The center core 3 is made of, for example, stainless steel (S
A metal material such as US) is formed so as to have a substantially disk shape as a whole, and is engaged with the disk engaging portion 7 for engaging with the disk substrate 2 to position the disk substrate 2 and the spring 4. And a spring engaging portion 8 for positioning the center core 3 and the spring 4 relative to each other.

The disk engaging portion 7 is formed in a convex shape having a size corresponding to the center hole 5 of the disk substrate 2, and is inserted into the center hole 5 of the disk substrate 2 to engage with the disk substrate 2. Have been adapted. The spring engaging portion 8 is formed in a convex shape having a size corresponding to a center hole 11 of the spring 4 described later.
By being inserted through the center hole 11 of the spring, the spring engaging portion 8 is engaged. The spring engaging portion 8 has a smaller diameter than the disc engaging portion 7 and is formed so as to protrude upward from a central portion of the disc engaging portion 7. And the center part of this spring engagement part 8,
In other words, when the disk-shaped recording medium 1 is mounted on the hard disk drive,
An insertion hole 9 through which the rotation shaft of the spindle motor is inserted is formed so as to penetrate in the thickness direction.

At the lower end of the disk engaging portion 7, a flange portion 10 protruding toward the outer peripheral side is formed. A mounting surface 10 a on which the disk substrate 2 is mounted when the disk engaging portion 7 is inserted into the center hole 5 of the disk substrate 2 is provided at the outer peripheral end of the flange portion 10.

The spring 4 is made of, for example, stainless steel (S
A metal material such as US) is formed into a generally disk-shaped elastically displaceable thin plate. A center hole 11 into which the spring engaging portion 8 of the center core 3 is inserted is formed in the center of the spring 4. The outer peripheral end of the spring 4 is provided with a convex pressing portion 12 formed in a substantially annular shape. This pressing portion 12
Are provided at positions corresponding to the substantially annular convex portions 6 provided on the disk substrate 2. When the spring 4 is engaged with the center core 3 with the disk substrate 2 interposed therebetween,
The substantially annular convex portion 6 provided on the disk substrate 2 is brought into contact with the entire circumference thereof.

In the pressing portion 12, the cross section of the spring 4 in the radial direction is, for example, substantially arc-shaped. The curvature of the annular pressing portion 12 is set to an optimum value according to various conditions such as the thickness of the disk substrate 2, the rigidity of the center core 3, and the rigidity of the spring 4.

In the above description, the pressing portion 12 formed substantially in an annular shape and brought into contact with the substantially annular convex portion 6 of the disk substrate 2 over the entire circumference has been exemplified.
2 is not limited to the above example, and is provided, for example, at a plurality of locations corresponding to the substantially annular convex portions 6 provided on the disk substrate 2, and provided on the disk substrate 2. It may be composed of a plurality of convex portions that abut discontinuously at a plurality of locations with the convex portion 6 of FIG.

In the disk-shaped recording medium 1, the center hole 5 of the disk substrate 2 is provided in the disk engaging portion 7 of the center core 3.
Is inserted, and the disk substrate 2 is mounted on the mounting surface 10a of the flange portion 10, so that the center core 3
And the disk substrate 2 are engaged. The center hole 11 of the spring 4 is inserted into the spring engaging portion 8 of the center core 3.
Is inserted, the spring 4 is engaged with the center core 3 while sandwiching the disk substrate 2 therebetween.

Here, the center core 3 and the spring 4
Are provided with screw holes 13 at several places on the same circumference, respectively.
And the spring 4 are fixed by being screwed. Thus, in the disc-shaped recording medium 1, the center core 3 and the spring 4 hold the center of the disc substrate 2. At this time, in the disk-shaped recording medium 1, the substantially annular pressing portion 12 provided on the spring 4 is provided.
Presses the disk substrate 2 in the thickness direction while abutting the substantially annular convex portion 6 of the disk substrate 2 over the entire circumference thereof, and presses the disk substrate 2 to the flange portion 10 provided on the center core 102. Is urged toward the mounting surface 10a.

Here, the center core 3 and the spring 4 are fixed by screws, but the center core 3 and the spring 4 can be fixed by providing a notch or the like and fixing by caulking, or It may be fixed by spot welding or the like.

In the disk-shaped recording medium 1 configured as described above, as shown in FIG. 3, the insertion hole 9 of the center core 3 is inserted into the rotary shaft 15 of the spindle motor provided on the hard disk drive main body 14. By doing
Attached to the hard disk drive. In the hard disk drive, when the disk-shaped recording medium 1 is rotationally driven by the spindle motor, a head actuator 16 provided in the hard disk drive main body 14 is provided.
Rotates in the radial direction on the signal recording surface of the disk-shaped recording medium 1. Thus, in the hard disk drive, the magnetic head 17 mounted on the tip of the head actuator 16 records and reproduces signals while flying above the signal recording surface of the disk-shaped recording medium 1.

Here, in the disk-shaped recording medium 1, as described above, the substantially annular convex portion 6 that comes into contact with the pressing portion 12 of the spring 4 is provided on the main surface of the disk substrate 2 on the side in contact with the spring 4. Are formed.

Thus, in the disk-shaped recording medium 1,
Center core 3 and spring 4 for disk substrate 2
Displacement of the contact portion with the contact can be suppressed. Therefore, in the disk-shaped recording medium 1, the moment force in the radial cross section of the disk substrate 2 can be reduced, and the entire disk-shaped recording medium 1 can be prevented from being deformed.

[0036]

Next, an embodiment in which a disk-shaped recording medium to which the present invention is applied is actually manufactured will be described. Further, a comparative example manufactured for comparison with these examples will be described. In the disc-shaped recording medium shown in FIGS. 4 to 8, the description of the same parts as those of the disc-shaped recording medium 1 shown in FIG.

In the first embodiment, as shown in FIG. 4, a substantially annular convex portion 6 which comes into contact with the spring 4 is provided on the main surface of the disk substrate 2 on the side in contact with the spring 4. This is a disk-shaped recording medium having a substantially annular convex pressing portion 12 that is in contact with the convex portion 6 of the disk substrate 2 at the outer peripheral end.

In the second embodiment, as shown in FIG. 5, a substantially annular convex portion 6 in contact with the spring 4 is provided on the main surface of the disk substrate 2 on the side in contact with the spring 4. The disk-shaped recording medium has a flat surface in contact with the disk substrate 2.

In Comparative Example 3, as shown in FIG. 6, both main surfaces of the disk substrate 2 on the side in contact with the center core 3 and the spring 4 are flat surfaces, and the disk substrate 2 This is a disk-shaped recording medium having a convex pressing portion 12 formed in a substantially annular shape in contact with the recording medium.

As shown in FIG. 7, the comparative example 4 has a substantially annular convex contacting the center core 3 and the spring 4 on both main surfaces of the disk substrate 2 on the side in contact with the center core 3 and the spring 4. This is a disk-shaped recording medium having a portion 6 and a convex pressing portion 12 formed in a substantially annular shape at the outer peripheral end of the spring 4 and in contact with the convex portion 6 of the disk substrate 2.

As shown in FIG. 8, the comparative example 5 has a substantially annular convex contacting the center core 3 and the spring 4 on both main surfaces of the disk substrate 2 on the side in contact with the center core 3 and the spring 4. This is a disk-shaped recording medium having a portion 6 and having a flat surface in contact with the disk substrate 2 of the spring 4.

With respect to the disc-shaped recording media of Examples 1 and 2, and Comparative Examples 1 and 3, each disc-shaped recording medium when the center core 3 and the spring 4 sandwich the center of the disc substrate 2 FIG. 9 shows the results of measuring the amount of deformation of. In FIG. 9, the horizontal axis indicates the radial position when the innermost peripheral portion of the disk substrate 2 is set to 0, and the vertical axis indicates the amount of displacement of the disk substrate 2 in the normal direction.

As is apparent from FIG. 9, in the first and second embodiments, almost no deformation is seen in the disk-shaped recording medium.

On the other hand, in Comparative Example 1, it can be seen that the disk substrate 2 is greatly deformed to the plus side. The disk-shaped recording medium of Comparative Example 1 has the same configuration as the above-described conventional hard disk medium 100, and the entire disk substrate 2 is deformed in an umbrella shape, and at the same time, is deformed so as to undulate in the circumferential direction.

Further, in Comparative Examples 2 and 3, the substantially annular convex portions which come into contact with the center core 3 and the spring 4 are provided on both main surfaces of the disk substrate 2 on the side in contact with the center core 3 and the spring 4. 6, the disk substrate 2
Is greatly deformed to the minus side. In this case as well, the entire disk substrate 2 is deformed into an umbrella shape, and simultaneously, the disk substrate 2 is deformed in a wavy manner in the circumferential direction.

Accordingly, in order to suppress the deformation of the disk-shaped recording medium, the main surface of the disk substrate 2 on the side in contact with the center core 3 is made flat and the main surface on the side in contact with the spring 4 It has been found that it is effective to provide a substantially annular convex portion 6 which comes into contact with the pressing portion 12 of the spring 4.

As described above, in the disk-shaped recording medium to which the present invention is applied, the substantially annular convex portion 6 which is in contact with the spring 4 is formed on the main surface of the disk substrate 2 on the side in contact with the spring 4. Therefore, the displacement of the contact portion between the center core 3 and the spring 4 with respect to the disk substrate 2 can be suppressed. Thereby, in this disk-shaped recording medium, the moment force in the radial cross section of the disk substrate 2 can be reduced, and the entire disk substrate 2 can be prevented from being deformed.

Therefore, in this disk-shaped recording medium, for example, in the case of a magnetic recording medium, the distance between the signal recording surface of the magnetic recording medium and the magnetic head can be reduced.
High reliability and high density magnetic recording can be realized.

Further, in this disk-shaped recording medium, for example, when a metal is used for the center core 3 and a resin material or glass is used for the disk substrate 2, the linear expansion coefficients between these members are different. Also, the moment force generated by the relative expansion and contraction deformation generated by the change in the ambient temperature can be reduced. As a result, the flatness of the disk-shaped recording medium becomes robust against temperature changes, and a disk-shaped recording medium with improved reliability that can be used in an environment with temperature changes can be obtained. .

The disk-shaped recording medium to which the present invention is applied employs any recording / reproducing method such as magnetic recording, magneto-optical recording, and optical recording in which a desired signal recording layer is formed on one or both surfaces of a disk substrate. The present invention can also be applied to a recording medium that performs recording.

[0051]

As described above in detail, the disk-shaped recording medium according to the present invention has a substantially annular convex portion centered on the center hole on the main surface of the disk substrate on the side of the elastic displacement member. However, since the convex portion is in contact with the elastic displacement member, the displacement of the contact portion between the center core and the elastic displacement member with respect to the disk substrate can be suppressed, and the moment force in the radial cross section of the disk substrate can be suppressed. Can be reduced.

Therefore, in this disk-shaped recording medium, the deformation of the disk substrate can be significantly reduced, and the disk substrate can be firmly held by the center core and the elastic displacement member.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of a disk-shaped recording medium to which the present invention is applied.

FIG. 2 is a sectional view of a main part showing a configuration of the disk-shaped recording medium.

FIG. 3 is a schematic perspective view showing a configuration of a hard disk drive in which the disk-shaped recording medium is mounted.

FIG. 4 is a cross-sectional view of a main part showing a configuration of a disk-shaped recording medium of Example 1.

FIG. 5 is a cross-sectional view illustrating a main part of a configuration of a disk-shaped recording medium according to a second embodiment.

FIG. 6 is a sectional view of a main part showing a configuration of a disk-shaped recording medium of Comparative Example 1.

FIG. 7 is a sectional view of a main part showing a configuration of a disk-shaped recording medium of Comparative Example 2.

FIG. 8 is a sectional view of a main part showing a configuration of a disk-shaped recording medium of Comparative Example 3.

FIG. 9 is a characteristic diagram showing a result of measuring a deformation amount of each disk-shaped recording medium when a center core and a spring sandwich a center portion of a disk substrate.

FIG. 10 is a perspective view showing a configuration of a conventional hard disk medium.

FIG. 11 is a cross-sectional view of a main part showing a configuration of the hard disk medium.

FIG. 12 is a fragmentary cross-sectional view for explaining a deformation of the hard disk medium.

[Explanation of symbols]

1 disk-shaped recording medium, 2 disk substrate, 3 center core, 4 spring, 5 center hole, 6 protrusion, 1
0 flange part, 10a mounting surface, 12 pressing part

Claims (2)

[Claims] 1. A substantially disk-shaped disk substrate having a center hole, a center core engaged with the center hole of the disk substrate, and an elastic displacement for holding the disk substrate together with the center core while pressing the disk substrate in a thickness direction. The disk substrate is provided on a main surface on the elastic displacement member side,
A disk-shaped recording medium having a substantially annular convex portion centered on the center hole, wherein the convex portion is in contact with the elastic displacement member. 2. The disk-shaped recording medium according to claim 1, wherein the disk substrate is formed by injection molding a resin material.