JP2001195727A - Disk for recording data and method for manufacturing the same and disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk for recording data recording which is capable enhancing the holding power of the disk by friction and may be stably operated without the deviation of the disk from a motor hub even if large impact is exerted thereto from outside, a method for manufacturing the same and a disk device. SOLUTION: A central hole 5 engaging with the motor hub of the disk device is formed in the central part of the disk 7 and a clamp region 9a abutting on a member used for fixation to the motor hub is formed on the outer periphery of the central hole 5. A data recording area 11 is formed on the outer periphery of the clamp region 9a. The surface roughness of the clamp region 9a is made greater than the surface roughness of the data recording region 11 and is approximated to the surface roughness of the member abutting on the clamp region 9a during the fixation to the motor hub.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording disk, a method of manufacturing the same, and a disk device.

[0002]

2. Description of the Related Art In recent years, HDDs have been required to have higher impact resistance. Particularly, HDDs of 2.5 inches or less, which are often mounted on notebook personal computers, have a shock resistance of 600 G or more when not operating. Some products have high performance. One condition for realizing such high impact resistance performance is that the magnetic disk is firmly held by the motor hub, and the magnetic disk does not shift with respect to the motor hub even when an impact is applied.

FIGS. 11 to 13 show a conventional disk drive and a magnetic disk used for the same. Hereinafter, the magnetic disk is referred to as a “disk”. As shown in FIG. 11, the disks 3a and 3b have a center hole 5 formed at the center of the disk surface to engage with the motor hub 6 of the disk device. The disks 3a and 3b are arranged via the spacer 4 so that the motor hub 6 and the center hole 5 are engaged with each other.
It is sandwiched between the clamp 2 and the motor hub 6 by the screws 1a to 1c, and is fixed to the motor hub 6 by the frictional force.

When the disks 3a and 3b are mounted and fixed to the motor hub 6, the disks 3a and 3b rotate and the head floats on the data recording area 11 on the disk surface to read or write data. As shown in FIG. 12, the disk device to which the disks 3a and 3b are fixed is moved between the disks 3a and 3b and members such as the clamp 2, the spacer 4, and the motor hub 6 by the tightening force N of the screws 1a to 1c. Frictional force P
1 to P3 occur.

Here, frictional force P1 = μ1 × N, P2 = μ
2 × N, P3 = μ3 × N, μ1 is the disk 3a
Coefficient of friction between the disk and the clamp 2, μ2 is the disk 3a, 3b
Represents the coefficient of friction between the disk 3b and the spacer 4, and μ3 represents the coefficient of friction between the disk 3b and the motor hub 6. R1 is disk 3
b is the radius of the outer diameter circle of the area where the motor hub 6 is in contact.

[0006]

In the disk device having the disks 3a and 3b fixed as described above, for example, when an external impact is applied, the disks 3a and 3b and the spacer 4 are removed.
Generates inertia forces F1 to F3. If the relationship of F1 + F2 + F3> (μ1 + μ3) × N holds with respect to this inertial force, the disks 3a and 3b are displaced from the motor hub 6.

As a result, a periodic fluctuation component of the permanent read signal is generated, which has a great effect on read / write and servo characteristics. In order to further increase the frictional forces P1 to P3, the tightening force N of the screws 1a to 1c may be increased.
There is a problem that the deformation of 3b becomes large and affects the flying characteristics of the head.

Conventionally, the disks 3a, 3b and the heads are prevented from being attracted to each other and the friction coefficient between the disks 3a, 3b and the heads is reduced.
Discs 3a and 3b having fine irregularities (texture) formed on the entire surface of b are used. However, if unevenness is formed on the entire surface of the disc, the data recording area 1
Because of the unevenness of 1, the flying height of the head cannot be reduced,
There is a problem that it is difficult to achieve high-density recording.

Therefore, in recent years, as shown in FIG.
In the data recording area 11, a disk 3c having a zone texture structure in which unevenness is formed only on a part of the disk without forming unevenness is often used. Specifically, disk 3
At the outer periphery of the center hole 5c, a clamp region 9b is formed which comes into contact with a member used for fixing to the motor hub 6, and the outer periphery is contacted by the head at the start of the operation of the disk drive and at the end of the operation. A contact start / stop (hereinafter, referred to as “CSS”) zone 10b is formed in which a texture is formed. Such a disk 3c
Is referred to as a CSS type disc 3c.

The unevenness of the CSS zone 10b is used to prevent the disk 3c from adsorbing to the head and to reduce the friction coefficient as described above. However, in order to avoid collision between the head and the disk 3c during flying, the unevenness of the CSS zone 10b is used. The height is 5 of the flying height
Usually, it is set to 0 to 60%. CSS zone 1
The inner diameter R2 of Ob is generally the same size as the radius R1 in FIG.

As a method of forming the unevenness of the CSS zone 10b, for example, a method of rubbing the surface of the disk 3c with a cloth or the like to roughen the surface is adopted. In such a method, as described above, the height of the unevenness is increased. Difficult to control. Therefore, in recent years, the formation of unevenness using a laser has become mainstream. In this method, laser light is intermittently applied to the surface of a rotating aluminum disk, and the irradiated disk surface is deformed by heat to form minute irregularities. This prevents the head from adsorbing, and further reduces the friction coefficient between the head and the disk.

By the way, in the above-mentioned method of roughening the disk surface with the cloth to form irregularities in the CSS zone 10b,
Irregularities are also formed in the clamp area 9b inside the SS zone 10b. Therefore, when the motor hub 6 is fixed as described above, a slight frictional force is generated between the clamp area 9b and members such as the clamp 2, the spacer 4, and the motor hub 6, which are in contact with the clamp area 9b. Since the height of the irregularities is limited as described above,
A sufficient coefficient of friction to achieve stable fixation cannot be obtained.

On the other hand, in the method of forming the unevenness by laser processing, since the unevenness is not formed in the clamp region 9b,
There is a problem that the coefficient of friction between the disk 3c and the member that fixes the disk 3c to the motor hub 6 is small, and the disk 3c cannot be fixed stably. In order to solve such a problem, U.S. Pat. No. 5,768,052 discloses a method in which a plurality of fine projections are formed on either the clamp 2 or the surface of the corresponding disk, and the clamp 2 is tightened with the screws 1a to 1c. The disk is fixed to the motor hub 6 by cutting into the surface of the contact with which the projection contacts.

In order to dig into the member with which the disk 3c comes into contact, the material on the surface on which the projection is formed must be harder than the material on the other surface. The material being used is clamp 2,
Since the disk 3c, the spacer 4, and the motor hub 6 are all made of aluminum and have no difference in hardness, realization is difficult.

It is conceivable that the clamp 2, the spacer 4, and the motor hub 6 are made of stainless steel harder than aluminum and the aluminum disk 3c is used. However, it is difficult to form many small sharp projections on the hard stainless steel surface. It is. In addition, when a glass disk that has begun to be used in recent years is used, if the protrusion is cut into the glass disk as described above, the glass disk may be broken. Conversely, it is conceivable to form small sharp projections on the surface of the glass disk. However, since the glass is fragile, there is a possibility that the projections may break before biting into the surfaces of the clamp 2 and the spacer 4.

In US Pat. No. 5,875,171, a texture is provided on the surface of the disk 3c which comes into contact with the clamp 2 and the spacer 4, and the clamp 2 and the spacer 4 are provided.
Is coated with a thin plastic film. With such a configuration, when the screws 1a to 1c are tightened, the texture of the disk bites into the plastic thin film and the disk is held firmly.

However, plastic thin film coating has the problems of high cost and high risk of generating undesirable gas from plastic. SUMMARY OF THE INVENTION The present invention solves the above problems, enhances the holding force of a disk by friction, and enables a disk to be stably operated without being displaced from a motor hub even when a large external impact is applied, a method of manufacturing the same, and a disk. It is intended to provide a device.

[0018]

A data recording disk according to the present invention is characterized in that the surface roughness of the clamp area is close to the surface roughness of the member to be brought into contact. According to the present invention, the holding force of the disk due to friction can be increased. The disk device of the present invention is characterized in that a disk having a special surface roughness in the clamp area is used.

According to the present invention, it is possible to provide a disk device that does not shift with respect to the motor hub even when a large external impact is applied, and that operates stably.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A data recording disk according to a first aspect of the present invention has a center hole formed in a center portion of a disk surface to be engaged with a motor hub of a disk device. A clamp area is formed in contact with a member used to fix the head, a data recording area is formed on the outer periphery of the clamp area, and the head is lifted up with respect to the data recording area on the rotating disk surface attached to the motor hub. A data recording disc for reading or writing data, wherein the surface roughness of the clamp area is larger than the surface roughness of the data recording area, and the surface roughness of the clamp area is fixed to the motor hub. The present invention is characterized in that the surface roughness of the member abutting on the clamp area is approximated.

According to the present invention, the holding force of the disk due to friction is increased, and the disk can be securely fixed to the disk device. The data recording disc according to claim 2 of the present invention is
According to a first aspect of the present invention, the surface roughness of the clamp area is formed to be at least about twice the surface roughness of the data recording area.

According to a third aspect of the present invention, in the data recording disk according to the first aspect, the surface roughness of the data recording area is 4 nm or less when evaluated by the center line average roughness, and the surface roughness of the clamp area is Is 9 nm or more when evaluated by center line average roughness. Claim 4 of the present invention
The data recording disk according to any one of claims 1 to 3, wherein a recording / reproducing method of the data recording area is any one of a magnetic recording method, a magneto-optical recording method, and a phase change recording method. And

According to a fifth aspect of the present invention, there is provided a data recording disk according to any one of the first to fourth aspects, wherein the surface roughness of the clamp area is made closer to the surface roughness of a member abutting the clamp area. An unevenness is formed in the clamp region. According to this configuration, the holding force of the disk due to friction can be increased. According to a sixth aspect of the present invention, there is provided a data recording disk according to the fifth aspect, wherein a clamp region having irregularities is formed on both surfaces of the disk.

According to this configuration, the holding force of the disk due to friction can be further increased. According to a seventh aspect of the present invention, in the data recording disk according to the fifth or sixth aspect, the cross-sectional shape of the irregularities in the radial direction of the disk is triangular or sinusoidal.

According to this configuration, the friction coefficient between the disk and the motor hub can be further increased. An eighth aspect of the present invention provides a data recording disk according to any one of the first to seventh aspects, wherein a main material of the disk is any of aluminum, glass, and plastic. According to a ninth aspect of the present invention, there is provided a disk drive, wherein a center hole of a disk is engaged with a motor hub to press and fix a clamp area, and the disk is driven to rotate so that a head floats on the surface of the disk to record data in a data recording area. A disk device for writing data to or reading data from a disk, wherein any one of the data recording disks described above is used as the disk.

According to this configuration, even when a large external impact is applied, the disk can operate stably without shifting with respect to the motor hub. 11. The method of manufacturing a data recording disk according to claim 10, wherein the outer periphery of a center hole of the disk mainly made of aluminum is irradiated with a laser beam to form irregularities, thereby forming a clamp region. The surface roughness is adjusted so as to be larger than the surface roughness of the data recording area on the outer periphery of the clamp area, and to approach the surface roughness of the member that comes into contact when fixed to the motor hub.

According to this configuration, the surface roughness of the clamp area of the disk can be easily adjusted. Claim 11 of the present invention
In the method for manufacturing a data recording disk described in the above, when manufacturing a data recording disk by melting a raw material containing glass as a main material and injection molding it into a mold, the mold corresponds to a clamp area of the disk. At the position, the surface roughness of the clamp area is larger than the surface roughness of the data recording area,
Injection molding of glass is performed using a metal mold having irregularities approaching the surface roughness of a member abutting upon fixing to a motor hub.

According to this configuration, irregularities in the clamp area of the disk can be easily formed. The method for manufacturing a data recording disk according to claim 12 of the present invention is characterized in that, when manufacturing a data recording disk by melting a raw material mainly composed of plastic and injection-molding the same into a mold, The surface roughness of the clamp area is larger than the surface roughness of the data recording area at a position corresponding to the clamp area, and a mold having irregularities approaching the surface roughness of a member abutting when fixed to the motor hub is used. It is characterized by performing plastic injection molding.

According to this structure, irregularities in the clamp area of the disk can be easily formed. Hereinafter, embodiments of the present invention will be described with reference to FIGS. Note that components having the same functions as those in FIGS. 11 to 13 showing the conventional example are denoted by the same reference numerals. (Embodiment 1) FIGS. 1 to 4 show (Embodiment 1) of the present invention.

In this (Embodiment 1), as shown in FIG. 1, the clamp area 9a of the CSS type magnetic disk 7 is used.
Is different from the above-mentioned conventional example in that the surface roughness of the member is made closer to the surface roughness of the member abutting on the clamp region 9a.
More specifically, a center hole 5 is formed at the center of the magnetic disk 7 to engage with the motor hub 6 of the disk drive. A clamp area is provided on the outer periphery of the center hole 5 for contacting a member used for fixing to the motor hub 6. 9a are formed, and the clamp area 9 is formed.
A CSS zone 10a is formed on the outer circumference of the data area a, and a data recording area 11 is further formed on the outer circumference of the CSS zone 10a. R3 indicates the radius of the outer diameter circle of the clamp area 9a, and
The size is almost the same as the radius R1 shown in FIG.

The configuration of the CSS zone 10a is the same as that of the conventional example, but the clamp area 9a is formed with irregularities having a surface roughness different from the conventional one. This clamp area 9
2a, the surface roughness of the data recording area 11 is larger than that of the data recording area 11, and as shown in FIG. The motor hub 6 is configured to approach the surface roughness.

The case where the magnetic disk 7 configured as described above is fixed to a disk device, here, the case where two disks are fixed will be described as an example. As shown in FIG. 2 (b), when the magnetic disks 7a and 7b are fixed to the disk device, the balanced state of the forces is as shown in FIG.
Due to the tightening force (vertical load) N of c, frictional forces P1 to P3 are generated between the magnetic disks 7a and 7b and members such as the clamp 2, the spacer 4, and the motor hub 6 which are in contact with the magnetic disks 7a and 7b. Here, frictional force P1 = μ1 × N, P2 = μ2 ×
N, P3 = μ3 × N where μ1 is the magnetic disk 7a
Coefficient of friction between the clamp 2 and the clamp 2, μ2 is the disc 7a, 7b
Represents the friction coefficient between the magnetic disk 7b and the motor hub 6, and μ3 represents the friction coefficient between the magnetic disk 7b and the motor hub 6. R1 is the radius of the outer diameter circle of the area where the disc 7b and the motor hub 6 are in contact.

In the disk device configured as described above,
For example, when an external shock is applied, the magnetic disks 7a, 7
b, Inertia forces F1 to F3 are generated in the spacer 4. At the moment when the displacement occurs between the disks 7a and 7b and the motor hub 6, the following equation is obtained. F1 = μ1 × N + μ2 × N F2 = μ2 × N + μ3 × N Therefore, if the values of F1, F2 and N are measured, the following can be obtained.
The coefficient of friction is determined from the equation.

Μ1 + μ2 = F1 / N μ2 + μ3 = F2 / N Therefore, in order to measure a suitable surface roughness of the clamp area 9a, the disks a to c having different center line average roughnesses of the clamp area 9a are used. The frictional force was measured by the frictional force measuring device shown in FIGS. However, in this experiment, since the difference between μ1, μ2, and μ3 cannot be determined, the average friction coefficient was calculated on the assumption that μ1, μ2, and μ3 are equal.

As shown in FIGS. 3A and 3B, the force gauge 16 of the frictional force measuring device 8 is fixed to the Z stage 17, and is configured to be driven up and down when the handle 18 is turned. When one of the two magnetic disks 7a and 7b of the motor / disk assembly, here the magnetic disk 7a, is fixed to the disk fixing base 20, the motor shaft is pulled by the force gauge 16 to pull the motor shaft.
The motor shaft and the force gauge 16 are connected using the arm 19 of the book.

When the force gauge 16 is raised while turning the handle 18 in this state, the load gradually increases and decreases at the moment when the disc 7a and the motor hub 6 are displaced. The maximum value is measured using the peak hold function of the force gauge 16 while reading the load during this time. Further, by measuring the height of the upper end surface of the motor hub 6 before and after the peak of the load, it can be confirmed whether or not the disc 7a and the motor hub 6 have really shifted at that time.

Table 1 shows the center line average roughness of the disks a to c used in the friction force measuring device 8 described above.

[0038]

[Table 1] FIG. 4 shows the relationship between the center line average roughness and the friction coefficient. According to the experimental results, the coefficient of friction showed that the center line average roughness was about 9n.
m, it was confirmed that it increased.

Since the center line average roughness of the data recording area 11 of a generally used disk is 4 nm or less, the surface roughness of the clamp area 9a is calculated from the above results. It is apparent that if the thickness is made about twice as large as the above, a high frictional force can be obtained and the holding force of the disk 7 due to the friction can be increased. In addition,
Table 1 also shows the surface roughness of the clamp 2, the motor hub 6, and the spacer 4 along with the center line average roughness of the disks a to c.

The same lathe processing is performed on the surfaces of the clamp 2 and the motor hub 5, and the surface of the spacer 4 is polished. In any case, the surface is subjected to precise processing in order to increase the dimensional accuracy, but the surface of the disk 7 has a roughness of 100 times or more. However, considering the processing cost of parts, this is a value that can be said to be a limit in the future.

Conversely, the clamps 2 of the disks 7a and 7b
If the surface roughness of the portion that comes into contact with the surfaces of the motor hub 6 and the spacer 4, that is, the surface roughness of the clamp region 9 a is close to the order of the surface roughness of these members, natural engagement occurs when the screws 1 a to 1 c are tightened. It is considered that a strong frictional force is obtained. Therefore, the disk c in which the center line average roughness of the clamp region 9a is 9 nm or more is the disk a
It is presumed that the reason why the coefficient of friction was higher than that of the disk b or the disk b was due to such a reason. The reason that the friction coefficient of the disks a and b is smaller than that of the disk c is that the surface of the clamp area 9a of the disks a and b is too smooth with respect to the surface roughness of the clamp 2, the motor hub 6 and the spacer 4. This is probably because the unevenness was less caught.

From the above results, it was found that the surface roughness of the clamp region 9a of the magnetic disk 7 was good if it was 9 nm or more. However, the upper limit is not particularly limited, and the surface of the member contacting the clamp region 9a is not limited. What is necessary is just to make it approach roughness. That is, the maximum height of the unevenness of the CSS zone 10a is usually set to 60% or less of the flying height in order to avoid collision between the head and the disk surface during flying, but the clamp area 9a is used only for fixing the disk. Since this is an area that is not related to the flying of the head, the maximum height of the texture unevenness can be increased.

As described above, by bringing the surface roughness of the clamp area 9a of the disk close to the surface roughness of the clamp 2, the motor hub 6, and the spacer 4 which comes into contact with the clamp area 9a, the protrusion on one side of the contact surface can be changed. Without engaging the surfaces or fitting the pre-formed recesses and protrusions on the two surfaces in contact with each other, a natural meshing or catching can be generated between the two surfaces, and the holding force of the disc by friction can be increased.

The magnetic disk 7 configured as described above
However, as shown in FIGS. 2A and 2B, when attached to the motor hub 6 of the disk device in the same manner as in the conventional example,
Data is read or written by floating the head on the data recording area 11 on the rotating disk surface. As a recording / reproducing method for the data recording area 11, a magnetic recording method, a magneto-optical recording method, a phase change recording method, or the like can be applied.

At this time, even if a large impact is applied from the outside, the frictional coefficient between the clamp area 9a and the member that comes into contact with the clamp area 9a is large. A friction holding force is obtained,
The magnetic disk 7 does not shift with respect to the motor hub 6, and a disk device that can operate stably can be realized. (Embodiment 2) FIGS. 5 and 6 show (Embodiment 2) of the present invention.

The second embodiment differs from the first embodiment in that a CSS type magnetic disk 7c containing aluminum as a main material is used, but the other basic structure is the same as that in the first embodiment. is there. The magnetic disk 7c of the CSS system shown in FIG. 5 is a magnetic disk 7c made of aluminum with a zone texture formed in the CSS zone 10a, like the magnetic disk 3c of the CSS system shown in FIG.

However, unlike the conventional magnetic disk 3c, the magnetic disk 7c has irregularities formed in the clamp area 9a and has a large surface roughness. The unevenness of the clamp region 9a is formed by the following procedure. The disk made mainly of aluminum is rotated in the direction of arrow A about the rotation shaft 14, and the laser beam 14 is applied to the clamp area 9a of the disk.

For example, if the irradiation position is moved in the radial direction while continuously irradiating the laser beam 14, the portion irradiated with the laser beam 14 is deformed to be concave by heat, so that the groove of the record disc is formed in the clamp area 9a. A continuous spiral groove is formed. FIG. 6 is an enlarged view of a cross section of the clamp region 9a along the line BC. In the clamp area 9a,
The convex portion 21a and the concave portion 21b are formed by the laser beam 14. The radial section of the disk 7c of the projection 21a and the recess 21b has a triangular or sinusoidal shape, and the surface roughness of the clamp region 9a is reduced by the unevenness as described in the first embodiment. It is larger than the surface roughness of the data recording area 11 on the outer periphery of 9a, and approaches the surface roughness of the member that comes into contact when fixed to the motor hub 6.

In order to form a surface having a large coefficient of friction, the difference between the convex portion 21a and the concave portion 21b, that is, the height H of the convex portion 21a is made larger than the flying height of the head.
In the conventional CSS-type magnetic disk 3c, irregularities are formed in the CSS zone 10b on the outer periphery of the clamp area 9b. However, the irregularities are made smaller than the flying height of the head in order to prevent collision between the head and the disk 3c. As a result, the friction coefficient between the head and the disk 3c is reduced, so that the clamp area 9a created in this (second embodiment) is used.
The unevenness of the target has a completely different purpose.

In the above description, an example in which the irregularities of the clamp area 9a are formed on one surface of the disk 7c has been described. However, the present invention is not limited to this, and may be formed on both surfaces of the disk 7c. Good. With this configuration, the frictional force of the disk 7c when set in the disk device can be further increased.

In the above description, the disk 7c is continuously irradiated with the laser beam 14 to form a continuous spiral groove such as a groove of a record disk in the clamp area 9a. The present invention is not limited to this. By changing the irradiation intensity of the laser beam 14 or by turning on and off the laser beam 14 intermittently instead of continuously, various shapes of irregularities can be formed.

(Embodiment 3) FIGS. 7 to 10 show (Embodiment 3) of the present invention. In this (Embodiment 3), a CSS-type magnetic disk 7 mainly composed of glass is used.
The difference is that d is used, but the other basic configuration is the same as the above (Embodiment 1).

In recent years, a disk 7d mainly made of glass has been used instead of the disk 7c mainly made of aluminum in the above (Embodiment 2). The advantages of the glass disk 7d over the aluminum disk 7c are that the surface has a high hardness and is not easily damaged, and the surface has excellent smoothness. With such features, the glass disk 7d
Are widely used in small hard disks mounted on portable devices such as 2.5-inch hard disks.

The glass disk 7d is manufactured by cutting a glass plate into a circular shape and polishing the surface.
The manufacturing cost is higher than the case c, and a method of compression-molding a molten glass material to reduce the cost is being studied. The present invention can be easily applied to this manufacturing method.

The details will be described below. The magnetic disk 7d mainly made of glass is manufactured by sandwiching a glass material melted between molds and closing upper and lower molds. As shown in FIGS. 7 and 8, for example, a pair of an upper mold 13a and a lower mold 13b are used as a mold used for compression molding.

On the inner surfaces of the upper mold 13a and the lower mold 13b, regions 15a and 15b having irregularities formed near the center axis 22 at positions corresponding to the clamp regions 9a of the disk are formed. The irregularities of the areas 15a and 15b are formed such that the surface roughness of the clamp area 9a is larger than the surface roughness of the data recording area 11 and approaches the surface roughness of a member that comes into contact with the motor hub 6 when fixed.

Then, the pair of dies 13a, 13b
The upper and lower molds 13a and 13b are closed by sandwiching a raw material mainly composed of molten glass, and the material is cured. 21
Is a space filled with the molten material. When the material cools and hardens, the molds 13a and 13b are opened and the glass disk 7d is taken out as shown in FIG.

The area 15 formed in the molds 13a and 13b
The concavo-convex shapes of a and 15b are transferred to the glass disk 7d, and a clamp region 9a having concavities and convexities similar to the above (Embodiment 1) is formed. F- of the clamp area 9a
A cross-sectional view taken along the line G, as shown in FIG.
And a concave portion 21b are formed, and the cross-sectional shape in the radial direction of the disk is triangular or sinusoidal. Due to the concave and convex portions, the clamp region 9a is formed as described in the first embodiment.
Is larger than the surface roughness of the data recording area 11 on the outer periphery of the clamp area 9a, and approaches the surface roughness of the member that comes into contact when the motor hub 6 is fixed.

The shape of the irregularities can be freely changed by changing the shapes of the regions 15a and 13b of the molds 13a and 13b.
Therefore, the height H of the unevenness and the pitch P of the unevenness in FIG. 10 can be freely set by changing the shape of the mold. With such a configuration, a disk mainly composed of glass can be easily manufactured.

(Embodiment 4) This (Embodiment 4) is different in that injection molding is performed using a raw material mainly composed of plastic as a raw material of a disk. This is the same as in mode 3). In recent years, disk substrates using plastic have been manufactured in order to further reduce the cost of disk materials compared to aluminum and glass.

In this case, the substrate is manufactured by molding plastic. A member which melts a raw material mainly composed of plastic and has a surface roughness of the clamp region 9a larger than a surface roughness of the data recording region 11 at a position corresponding to the clamp region 9a of the disk, and which abuts upon fixing to the motor hub 6. Injection molding may be performed on a mold having irregularities approaching the surface roughness of the mold.

Examples of the material mainly composed of plastic include polycarbonate and the like. With such a configuration, the same effect as described above can be obtained.
In each of the above embodiments, the CSS type magnetic disk has been described as an example. However, the present invention is not limited to this, and can be applied to a non-contact start / stop type disk device.

[0063]

As described above, according to the data recording disk of the present invention, the surface roughness of the clamp area is made larger than the surface roughness of the data recording area, and the clamp area of the disk device for fixing this disk is By bringing the disk closer to the surface roughness of the abutting member, the holding power of the disk due to friction is increased, and a reliable disk device that can operate stably without being displaced from the motor hub even when a large external impact is applied. realizable.

[Brief description of the drawings]

FIG. 1 is a plan view of a magnetic disk according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram and a cross-sectional view of a disk device according to Embodiment 1 of the present invention.

FIG. 3 is a front view and a side view of the frictional force measuring device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a center line average roughness and a friction coefficient according to the first embodiment of the present invention.

FIG. 5 is a schematic view showing a manufacturing process of a disk according to (Embodiment 2) of the present invention.

FIG. 6 is a sectional view of the disk according to the second embodiment of the present invention, taken along line BC.

FIG. 7 is a configuration diagram of a mold according to (Embodiment 3) of the present invention.

FIG. 8 is a sectional view of a mold according to (Embodiment 3) of the present invention.

FIG. 9 is a configuration diagram of a disk and a mold according to (Embodiment 3) of the present invention.

FIG. 10 is a sectional view taken along the line FG in (Embodiment 3) of the present invention;

FIG. 11 is a configuration diagram showing attachment of a conventional disk to a motor hub.

FIG. 12 is a sectional view of a conventional disk drive.

FIG. 13 is a plan view of a conventional disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw 2 Clamp 4 Spacer 6 Motor hub 7 Disk 9a Center hole 11 Data recording area 12 Laser beam

Claims (12)

[Claims] 1. A center hole for engaging a motor hub of a disk drive is formed at a center portion of a disk surface, and a clamp area for abutting a member used for fixing to the motor hub is formed on an outer periphery of the center hole. A data recording disk in which a data recording area is formed on an outer periphery of the clamp area, and a data recording area for reading or writing data by floating a head on a data recording area on a rotating disk surface attached to the motor hub, For data recording, the surface roughness of the clamp area is larger than the surface roughness of the data recording area, and the surface roughness of the clamp area is close to the surface roughness of a member abutting on the clamp area when fixed to the motor hub. disk. 2. The data recording disk according to claim 1, wherein the surface roughness of the clamp area is formed at least twice as large as the surface roughness of the data recording area. 3. The surface roughness of the data recording area is 4 nm or less when evaluated by the center line average roughness, and the surface roughness of the clamp area is 9 nm or more when evaluated by the center line average roughness. Disc for recording data as described. 4. The data recording disk according to claim 1, wherein the recording / reproducing method of the data recording area is any one of a magnetic recording method, a magneto-optical recording method, and a phase change recording method. 5. The data recording device according to claim 1, wherein the clamp region is formed with irregularities such that the surface roughness of the clamp region approaches the surface roughness of a member abutting the clamp region. Disk. 6. The data recording disk according to claim 5, wherein the clamp area having the unevenness is formed on both surfaces of the disk. 7. The data recording disk according to claim 5, wherein the cross-sectional shape of the radial unevenness of the disk is triangular or sinusoidal. 8. The main material of the disk is any one of aluminum, glass and plastic.
A data recording disc according to any one of the above. 9. A motor hub is engaged with a center hole of a disk to press and fix a clamp area, and the disk is driven to rotate so that a head floats on the surface of the disk to write data to a data recording area or to write data to the data recording area. A disk device for reading data, wherein the data recording disk according to claim 1 is used as a disk. 10. A clamp region is formed by irradiating a laser beam to an outer periphery of a center hole of a disk mainly made of aluminum to form a concavity and convexity, and a surface roughness of the clamp region is measured by using data of the outer periphery of the clamp region. A method for manufacturing a data recording disc, wherein the data recording disc is adjusted so as to be larger than the surface roughness of a recording area and to approach the surface roughness of a member that comes into contact when fixed to a motor hub. 11. A method of manufacturing a data recording disk by melting a raw material mainly composed of glass and compressing and molding the raw material into a metal mold, wherein the metal mold is provided at a position corresponding to the clamp area of the disk. Manufacture of data recording discs in which compression molding of glass is performed using a metal mold with a surface roughness larger than the surface roughness of the data recording area and having irregularities approaching the surface roughness of the member that comes into contact when fixed to the motor hub Method. 12. When manufacturing a data recording disc by melting a raw material containing plastic as a main material and injection-molding the same into a mold, the clamp area of the clamp area is used as the mold at a position corresponding to the clamp area of the disc. Manufacture of data recording discs in which plastic injection molding is performed using a mold with a surface roughness greater than the surface roughness of the data recording area and with irregularities approaching the surface roughness of the member that comes into contact when fixed to the motor hub Method.