JPH10134539A - Disk-shaped recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in a conventional disk of a hub-chucking type, wherein a center hub is secured by an adhesive to a disk main body part, so that the disk main body part warps or is deformed because of a difference of amounts of thermal expansion when the disk main body part and center hub are formed of materials of different thermal expansion coefficients. SOLUTION: A disk-shaped recording medium has a disk main body part 2 and a center hub 3 set at a center hole 2a of the disk main body part 2. The center hub 3 is magnetically attracted to a disk table of a recording/ reproducing apparatus, thereby being chucked on the disk table. The center hub 3 is constituted of an upper and a lower hub-composing bodies 11, 12 holding an upper and a lower faces of the disk main body parts 2 therebetween. The upper hub-composing body 11 is fomred of synthetic resin, while the lower hub-composing body 12 is formed of metal with magnetic properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called hub chuck in which a center hub is attached to a center hole of a recording medium main body, and is fixed on a disk table of a recording / reproducing apparatus via the center hub. The present invention relates to a king-type disk-shaped recording medium (carrier).

[0002]

2. Description of the Related Art As a hub chucking type disk-shaped recording medium (carrier), those shown in FIGS. 11 to 12 are known. FIG. 11 is an exploded perspective view of a disk-shaped recording medium, and FIG. 12 is a cross-sectional view in a used state. The disc-shaped recording medium 101 includes a recording medium main body 102 having a signal recording surface, and a center hole 102a of the recording medium main body 102.
And a center hub 103 attached to the center hub.

The recording medium main body 102 is made of a material such as synthetic resin or glass and is formed in a disk shape having the central hole 102a at the center.

[0004] The center hub 103 is formed of a magnetic metal plate such as iron and has a bottomed cylindrical shape having a flange portion 103a.

The center hub 103 inserts a cylindrical portion 103b continuous with the flange portion 103a into a central hole 102a of the recording medium main body 102, and attaches the flange 103a to the upper surface of the recording medium main body 102 with an adhesive 104.
And is attached to the recording medium main body 102.

When the disc-shaped recording medium 101 is inserted into a recording / reproducing apparatus, as shown in FIG. 12, the center hub 103 is attracted by a magnet 202 provided on a disc table 201 of the recording / reproducing apparatus. The disk-shaped recording medium 101 is chucked (adsorbed and fixed) on the hub support surface 203 of the turntable 201.

[0007]

As described above, the conventional disk-shaped recording medium 101 is attached to the recording medium main body 102 made of synthetic resin or glass, and the adhesive 104 of the metal center hub 103 is attached. In this case, there is a problem as described below.

(1) Since the recording medium main body 102 and the center hub 103, which are made of materials having different coefficients of thermal expansion, are firmly connected with the adhesive 104, the disk-shaped recording medium 101 has a high-temperature atmosphere. The recording medium main body 102 is warped or deformed due to the difference in the thermal expansion coefficient when the recording medium is exposed. In a disk-shaped recording medium in which a large capacity is achieved by high-density recording, even a slight warping or deformation may cause a defect such as a recording defect or a reproduction defect.

(2) After the adhesive 104 has solidified, it is difficult to correct the attachment position of the center hub 103 to the recording medium main body 102 and the like.

The present invention solves the above-mentioned conventional problems, prevents the recording medium main body from being warped or deformed due to a rise in temperature, and can easily attach the center hub to the recording medium main body. It is intended to provide a disk-shaped recording medium.

[0011]

According to the present invention, there is provided a recording medium main body, and a center hub attached to a center hole of the recording medium main body. In a disk-shaped recording medium which is sucked and chucked on the disk table, an upper hub structure made of synthetic resin sandwiching the center hub between the upper and lower surfaces of the recording medium main body. And a lower hub component made of a metal having magnetism.

[0012]

FIG. 1 is a perspective view of a disk-shaped recording medium (hereinafter, referred to as a disk) 1 and a recording / reproducing device 301 (hereinafter, referred to as a drive device) according to a first embodiment of the present invention. The disk 1 includes a recording medium main body (hereinafter, disk main body) 2 and a center hub 3 attached to the center of the disk main body 2, and is rotatably housed in a cartridge (case) 4. Have been. At the front end of the cartridge 4, an opening 5 for inserting a head is provided. A shutter 6 is rotatably attached to the opening 5.

When the cartridge 4 is inserted into the cartridge loading portion 302 of the drive device 301, the shutter 6 is opened by a shutter opening member (not shown) provided in the drive device 301, and the opening 5 is opened.
As a result, the tip of the rotary actuator 303 of the drive device 301 enters the cartridge 4. When the cartridge 4 is completely loaded in the cartridge loading section 302, the disk table 305 attached to the spindle shaft 304 moves upward, so that the disk table 305 is opened from the spindle insertion opening provided on the bottom of the cartridge 4. The cartridge 1 enters the cartridge 4 and attracts the center hub 3 by the magnet 306 to chuck the disk 1 on the disk table 305. The center hub 3 is lifted from the lower half 4a of the cartridge 4 and is rotatable. State.

FIG. 2 is an exploded perspective view of the disk 1.
The disk main body 2 is made of a synthetic resin such as a polycarbonate resin, a polystyrene resin, a polyolefin resin, a norbornene resin, a polymethyl methacrylate resin, or the like, or aluminum or glass.
It is formed in the shape of a disk having a thickness of about 0.5 to 3 mm and has a magnetic recording layer, a magneto-optical recording layer, or an optical recording layer on its main surface.

The center hub 3 is composed of an upper hub structure 11 made of synthetic resin sandwiching the upper and lower surfaces of the disk main body 2 and a lower hub structure 12 made of magnetic metal. .

The upper hub assembly 11 includes a cylindrical portion 11a,
Flange part 11b provided at one end of cylindrical part 11a
And the cylindrical portion 11a and the flange portion 11b
Are integrally formed of a thermoplastic synthetic resin such as polycarbonate and polyacetal having excellent mechanical strength.

The cylindrical portion 11a has substantially the same outer diameter as the center hole 2a of the disk main body 2 and has
It is formed in a cylindrical shape having a length several times as large as the thickness of the disk main body 2, and can be closely fitted into the center hole 2a of the disk main body 2.

The flange portion 11b is formed in a plate shape having a diameter larger than that of the center hole 2a of the disk main body 2, and an annular projection 11c is provided on the outer peripheral portion of the lower surface.

Then, the cylindrical portion 11a is inserted into the center hole 2a from the upper surface side of the disk main body 2 so that the distal end of the cylindrical portion 11a protrudes from the lower surface side of the disk main body 2 by a predetermined amount. In this state, the flange 1
An annular projection 11c provided on the lower surface of 1b is in contact with the upper surface of the disk main body 2.

The cylindrical portion 11a has a slit 1 for reducing the diameter.
1d, the outer peripheral surface is formed on a rough surface 11e for preventing slipping, and the slit 11d allows the cylindrical portion 11a to
a and the press-fit into the cylindrical portion 12a of the lower hub structure 12 described below can be easily performed, and the rough surface 11e allows the center hole 2a of the disk 2 to be formed. Also, it does not easily come out of the cylindrical portion 12a of the lower hub structure 12.

The lower hub structure 12 includes a cylindrical portion 12a,
Flange part 12b provided at one end of cylindrical part 12a
And the cylindrical portion 12a and the flange portion 12b
Is integrally formed by pressing a metal plate having magnetism, for example, a thin plate of SUS430.

The cylindrical portion 12a is formed to have the same diameter as or slightly smaller than the outer diameter of the cylindrical portion 11a of the upper hub structure 11.
Of the cylindrical portion 11a can be press-fitted. The cylindrical portion 12a of the lower hub assembly 12
Is formed in a cylindrical shape with a bottom, and has a spindle shaft insertion hole 12d in the center of the bottom surface 12c. The flange portion 12b is formed to have substantially the same diameter as the flange portion 11b of the upper hub structure 11, and
1b, the upper and lower surfaces of the disk main body 2 are sandwiched.

The center hub 3 of the first embodiment has the above-described structure.
The cylindrical portion 12a of the lower hub assembly 12 is positioned below the lower portion, and the flange portion 12b is brought into contact with the peripheral edge of the center hole 2a to support the lower surface of the disk main body 2 with the flange portion 12b. Next, the cylindrical portion 11a of the upper hub structure 11 is inserted into the center hole 2a from above the disk main body 2, and the distal end of the cylindrical portion 11a is connected to the cylindrical shape of the lower hub structure 11. When the flange portion 11b is pressed into the portion 12a and the flange portion 11b is brought into contact with the upper surface of the disk main body portion 2, the upper and lower hub components 11, 12 are connected to each other, and are connected by the flange portions 11b, 12b. The upper and lower surfaces of the disk main body 2 are sandwiched.

As described above, the disk 1 of the first embodiment
Since the upper and lower surfaces of the disk 2 are sandwiched between the flange portions 11b and 12b of the upper and lower hub components 11 and 12, the disk body 2 and the center hub 3 are made of materials having different thermal expansion coefficients. Even when the disk main body 2 and the center hub 3 are exposed to high temperature and the difference in the amount of thermal expansion occurs between them, the disk main body 2 and the center hub 3 In between, the disk body 2 is prevented from warping or deforming due to slippage.

FIG. 4 shows a disk 1 of the second embodiment.
In this embodiment, the upper hub structure 11 is also formed in a cylindrical shape with a bottom similarly to the lower hub structure 12, and a spindle shaft insertion hole provided on the bottom surface 12c of the lower hub structure 12 at the bottom surface 11f. The upper portion 12d is closed to prevent dust and the like from entering through the insertion hole 12d and adhering to the disk main body 2.

The bottom surface 11f of the upper hub structure 11 is
An outer peripheral portion is provided on an inner peripheral side of the annular superposed surface 11g and an annular superposed surface 11g overlapping the bottom surface 12c of the tubular portion 12a of the lower hub structural member 12, and A non-overlapping surface 11h which is raised from the bottom surface 12c of the cylindrical portion 12a, and a spindle shaft housing space G is formed between the non-overlapping surface 11h and the bottom surface 12c. I have.

FIG. 5 shows a modification of the second embodiment. In this modification, the bottom surface 11f of the upper hub
Is formed thinner than other portions of the cylindrical portion 11a, and the cylindrical portion 11a is
When press-fitting the cylindrical portion 11a, the cylindrical portion 11a is not obstructed in compressing the cylindrical portion 11a. The other configuration is the same as that of the first embodiment, and a duplicate description will be omitted.

FIG. 6 shows a third embodiment. In this embodiment, the bottom surface 1 of the tubular portion 11a of the upper hub
1f and the bottom surface 12c of the cylindrical portion 12a of the lower hub assembly 12.
Are bonded with an adhesive 21. As the adhesive 21, a hot-melt adhesive is used.

FIG. 7 shows an example in which the hot melt adhesive 21 is applied by the application device 401. The coating device 401 includes an adhesive tank 403 that sends out the contained adhesive by introducing compressed air through an air pipe 402 and pressurizing the same, and a lower hub structure that sends the adhesive 21 sent from the tank 403 to the lower hub. A nozzle 404 for applying the ink to the bottom surface 12c of the nozzle 12 is provided. The adhesive tank 403 includes a first heater 405 and a temperature sensor 40.
The nozzle 404 is provided with a second heater 4.
07 and a temperature sensor 408. The first heater 405 and the temperature sensor 406 and the second heater 407 and the temperature sensor 408 are controlled by a controller 409. And
Immediately before the adhesive is discharged from the nozzle 404, that is, immediately before the adhesive is applied, the temperature of the adhesive 21 in the tank 403 is increased by raising the adhesive 21 to a predetermined application temperature by the second heater 407. By lowering the quality, deterioration of the quality of the adhesive 21 is suppressed.

The hot melt adhesive 21 is applied to the cylindrical portion 1 of the lower hub assembly 12 by the application device 401.
The cylindrical portion 11a of the upper hub assembly 11 is pressed into the cylindrical portion 12a and heated by being applied to the outer peripheral portion on the bottom surface 12c of the cylindrical portion 12a.
An annular overlapping portion 11g of f is bonded.

As the adhesive 21, an ultraviolet curable adhesive can be used in addition to the hot melt adhesive.
When an ultraviolet curing type adhesive is used for the adhesive 21, the upper hub structure 11 is formed of a light-transmitting synthetic resin such as polycarbonate, and ultraviolet rays are transmitted through the bottom surface 11 f of the upper hub structure 11. And the adhesive 21 may be cured. The other configuration is the same as that of the first and second embodiments, and the duplicate description will be omitted.

FIG. 8 shows a fourth embodiment. In this embodiment, the bottom surface 1 of the tubular portion 11a of the upper hub
The connecting projections 31 are provided on the lower surface of the annular overlapping portion 11g of 1f.
31 and the cylindrical portion 1 of the lower hub structure 12.
The case where the projection fitting holes 32...

When the tubular portion 11a of the upper hub structure 11 is inserted into the tubular portion 12a of the lower hub structure 12, the tips of the projections 31... 31 pass through the projection fitting holes 32. Since the protrusion protrudes from the bottom surface 12c of the cylindrical portion 12a of the hub component 12, the tip portion is melted and deformed as shown in FIG. 33 to form the upper hub assembly 11
And the lower hub structure 12 are integrally connected.

FIG. 10 shows a modification of the fifth embodiment. In this modification, the cylindrical portion 12 of the lower hub
The lower surface of the bottom surface 12c is provided with a recess 34 into which the head 33 is inserted.
Are housed so as not to protrude from the lower surface of the bottom surface 12c. Other configurations are the same as those of the first, second, third, and fourth embodiments, and therefore, duplicated description will be omitted.

In the embodiment shown in the drawings, the coupling projection 3 is provided on the bottom surface 11f of the cylindrical portion 11a of the upper hub assembly 11.
1 is provided, but coupling projections 31... 31 are provided on the bottom surface 12 c of the cylindrical portion 12 a of the lower hub assembly 12, and projections are formed on the bottom surface 11 f of the cylindrical portion 11 a of the upper hub assembly 11. 32 may be provided.

[0036]

The disk of the present invention has the following effects.

(1) In the disk according to the first aspect, the upper hub component is formed of a synthetic resin, and the lower hub component is formed of a magnetic metal. Therefore, both the upper hub component and the lower hub component are formed. Lightening and cost reduction can be achieved as compared with the case of forming with metal. Also, the upper and lower hub components sandwich and support the disk body,
When a difference occurs in the amount of thermal expansion between the disk main body and the upper and lower hub components, slippage occurs between the two, and the conventional center hub of the disk main body is bonded with an adhesive. In addition, it is possible to prevent the disk main body from being warped or deformed, and it becomes a highly reliable product suitable for high-density recording.

(2) The disk according to the second aspect of the present invention combines the upper and lower hub components integrally by a simple operation of press-fitting the cylindrical portion of the upper hub component into the cylindrical portion of the lower hub component. can do.

(3) In the disk according to the third aspect, the upper portion of the spindle shaft insertion hole provided on the bottom surface of the lower hub structure is closed by the bottom surface of the upper hub structure, and dust and the like enter from the spindle shaft insertion hole. Thus, it can be prevented from adhering to the disk body.

(4) In the disk of the fourth and fifth aspects, the upper and lower hub structures can be securely and firmly connected by the adhesive.

(5) In the disk according to the sixth aspect, the upper and lower hub structures can be securely secured without using an adhesive or the like by the coupling projection fitting holes formed on the bottom surfaces of the upper and lower hub structures. , Can be firmly connected.

(6) The disk according to claim 7, wherein the head of the coupling projection is prevented from protruding from the bottom surface of the cylindrical portion of the lower hub structure, and the disk is chucked to the turntable of the recording / reproducing apparatus. King etc. can be performed reliably.

[Brief description of the drawings]

FIG. 1 is a perspective view of a disk and a drive device.

FIG. 2 is an exploded perspective view of the first embodiment.

FIG. 3 is a sectional view.

FIG. 4 is a sectional view of a second embodiment.

FIG. 5 is a sectional view of a modification.

FIG. 6 is a sectional view of a third embodiment.

FIG. 7 is a side view of the adhesive application device.

FIG. 8 is an exploded perspective view of the fourth embodiment.

FIG. 9 is a sectional view.

FIG. 10 is a sectional view of a modification.

FIG. 11 is an exploded perspective view of a conventional example.

FIG. 12 is a sectional view in a use state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disk-shaped recording medium (disk), 2 ... Recording medium main body (disk main body), 2a ... Center hole, 3 ... Center hub, 11 ... Upper hub structure, 11a ... Cylindrical part, 11b
... Flange portion, 11f ... Bottom surface, 12 ... Lower hub structure,
12a: cylindrical portion, 12b: flange portion, 12c: bottom surface,
12d: spindle shaft insertion hole, 21: adhesive, 31: coupling projection, 32: projection fitting hole, 33: head, 34: recess for accommodating the head.

Claims (7)

[Claims] 1. A recording medium main body, and a center hub attached to a center hole of the recording medium main body, wherein the center hub is magnetically attracted to a disk table of a recording / reproducing apparatus, and In the disk-shaped recording medium adapted to be chucked, the center hub is composed of an upper and lower surface hub structure that sandwiches the upper and lower surfaces of the recording medium body, and the upper hub structure is The lower hub structure is made of a synthetic resin, and the lower hub structure is made of a magnetic metal. 2. The upper and lower hub component according to claim 1, wherein the upper and lower hub components have cylindrical portions, and the cylindrical portion of the upper hub component is press-fitted into the cylindrical portion of the lower hub component. And a disc-shaped recording medium, wherein the upper and lower hub members are combined. 3. The upper hub structure according to claim 1, wherein the cylindrical portion of the lower hub structure is formed in a bottomed cylindrical shape, has a spindle shaft insertion hole in a center portion of the bottom surface, and has an upper hub structure. The cylindrical portion is also formed into a bottomed cylindrical shape, and the bottom surface of the cylindrical portion closes a spindle shaft insertion hole provided on the bottom surface of the cylindrical portion of the upper hub structure. A disk-shaped recording medium characterized by the following. 4. The upper and lower hub components according to claim 3, wherein the bottom surface of the cylindrical portion of the upper hub component and the bottom surface of the lower hub component are bonded with an adhesive. Disk-shaped recording medium. 5. The disk-shaped recording medium according to claim 4, wherein the adhesive is an ultraviolet-curable adhesive. 6. The cylindrical structure according to claim 1, wherein the cylindrical portions of the upper and lower hub components are formed in a bottomed cylindrical shape, and a coupling projection is formed on a bottom surface of one of the cylindrical portions. A projection fitting hole is formed on the bottom surface of the other cylindrical portion to fit the projection. The projection is inserted into the projection fitting hole, and the projection protrudes from the projection fitting hole. A disk-shaped recording medium characterized in that the tip portion of the disk-shaped recording medium is deformed to form a retaining head having a diameter larger than that of the projection fitting hole, and the upper and lower hub components are combined. 7. The disk-shaped recording device according to claim 6, wherein a head housing recess for housing a head of the coupling projection is provided on a bottom surface of the cylindrical portion of the lower hub structure. Medium.