JPH10134536A - 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 bonded to a disk main body part by an adhesive, so that the disk main body part is warped or deformed because of a difference of amounts of thermal expansion when the disk main body part and the center hub are formed of materials of different thermal expansion coefficients. SOLUTION: A disk-shaped recording medium 1 has a disk main body part 2 and a center hub 3 mounted 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 part 2 therebetween. The upper hub-composing body 11 is formed of synthetic resin, while the lower hub-composing body 12 is coupled by a metallic or synthetic resin pin 13.

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 Hub-chucking type disc-shaped recording media (carriers) shown in FIGS. 10 to 11 are known. FIG. 10 is an exploded perspective view of a disk-shaped recording medium, and FIG. 11 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. 11, 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 has a metal center hub 103 attached to a synthetic resin or glass recording medium main body 102 with an adhesive 104 as described above. 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 the disk-shaped recording medium which is sucked and chucked on the disk table, the center hub is formed by the upper and lower hub structures sandwiching the upper and lower surfaces of the recording medium main body. The upper and lower hub members were connected by pins for connecting the upper and lower hub members.

[0012]

FIG. 1 shows a disc-shaped recording medium (hereinafter, referred to as a disc) 1 and a recording / reproducing apparatus 301 according to the present invention.
FIG. 1 is a perspective view of a drive device (hereinafter, referred to as a drive device). 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. The center hub 3 is rotatably housed in a cartridge (case) 4. 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 a pair of upper and lower hub members 11 and 12 having a magnetic property such as stainless steel or iron and sandwiching the upper and lower surfaces of the disk body 2.

The upper and lower hub components 11 and 12 are connected to each other by pins 13 while holding the upper and lower surfaces of the disk main body 2 therebetween.

The upper hub structure 11 has a cylindrical portion 11a formed to have an outer diameter smaller than the center hole 2a of the disk main body 2, and the center formed at one end of the cylindrical portion 11a. The flange portion 11b has a larger diameter than the hole 2a, and an annular concave portion 11c is formed in the flange portion 11b.

The cylindrical portion 11a is formed in a cylindrical shape with a bottom, and an outer peripheral portion of a bottom surface 11d has a ring-shaped overlapping portion which overlaps a bottom surface (chucking surface) 12c of the lower hub assembly 12 described below. Portion 11e, and the inside of the overlapping surface 11e is the bottom surface 12c of the lower hub structure 12.
Is formed as a cylindrical non-overlapping portion 11f connected to the spindle shaft insertion hole 12d formed at the center.

In the annular overlapping portion 11e, three pin insertion holes 14 are formed on the same circumference at equal angular intervals around the cylindrical non-overlapping portion 11f.

The lower hub component 12 has a cylindrical portion 12a formed with an inner diameter larger than the outer diameter of the cylindrical portion 11a of the upper hub component 11, and one end of the cylindrical portion 12a. The disk body 2 has a flange portion 12b having a diameter larger than the center hole 2a of the disk body portion 2.
2b and the flange portion 11b of the upper hub structure 11,
The upper and lower surfaces of the disk main body 2 are clamped.

The cylindrical portion 12a is formed in a cylindrical shape with a bottom, and a spindle shaft insertion hole 12d is formed in the center of a bottom surface (chucking surface) 12c. Three pin insertion holes 15... 15 are formed on the same circumference around 12d at regular angular intervals.

The pin insertion hole 14 of the upper hub structure 11
.., And pin insertion holes 15 of the lower hub assembly 12.
Are formed in substantially the same size on the same circumference having substantially the same diameter, and as shown in FIG.
The upper and lower surfaces of the disk main body 2 are sandwiched between the flange portions 11b and 12b, and the cylindrical portion 11a of the upper hub structure 11 is inserted into the cylindrical portion 12a of the lower hub structure 12. When the overlapping portion 11e of the bottom surface 11d of the cylindrical portion 11a of the upper hub structure 11 is overlapped with the bottom surface 12c of the cylindrical portion 12a of the lower hub structure 11, The pin insertion holes 14 ... 14 and the pin insertion holes 15 ... 15 of the lower hub assembly 12 overlap with each other, and the cylindrical non-overlapping portion 11 of the upper hub assembly 11
f is located directly above the spindle shaft insertion hole 12d of the lower hub assembly 12.

The pins 13 for coupling the upper and lower hub members are
The shaft portion 13a formed to have a smaller diameter than the pin insertion holes 14 ... 14, 15 ... 15, and the pin insertion holes 14 ... 1
4, 15,... And a head 13b formed to have a larger diameter than that of the head 13b. Then, as shown in FIG. 4, the shaft 13a of the pin 13 is inserted into the pin insertion holes 15 and 14 from below the lower hub structure 12, and the tip of the shaft 13a is connected to the upper hub structure. The overlapping portion 11 on the bottom surface 11d of 11
e, and then pressed by a press device 403 comprising a punch (upper jig) 401 and a die (lower jig) 402 as shown in FIG. 5, and as shown in FIG. The head 13c is formed by enlarging the tip of the shaft portion 13a, and the upper and lower hub components 11, 12 are integrally connected.

The disk 1 of the first embodiment has the above-described structure, and the upper and lower surfaces of the disk 2 are clamped by the flange portions 11b and 12b of the upper and lower hub structures 11 and 12, respectively. For example, the disk main body 2 and the center hub 3 are made of materials having different thermal expansion coefficients, and the disk main body 2 and the center hub 3 are exposed to high temperature, and the thermal expansion between the two. Even if there is a difference in volume,
Slippage occurs between the disk main body 2 and the center hub 3 to prevent the disk main body 2 from warping or deforming.

FIG. 7 shows a second embodiment. In this embodiment, a case is shown in which the pins 13 for connecting the upper and lower hub components are formed of a thermoplastic synthetic resin. Pin 13 above
Has a shaft 13a and a head 13b like the metal pin of the first embodiment, and forms the head 13c by deforming the tip of the shaft 13a with an ultrasonic welding machine 501. Thus, the upper and lower hub components 11 and 12 are connected. The ultrasonic welding machine 501 presses the horn 502 for forming a head against the tip of the synthetic resin pin 13 and applies ultrasonic vibration to the pin 1.
The head 13c is formed by deforming the tip of the third part. Reference numeral 503 denotes a hub support as a lower jig.

FIG. 8 shows a modification of the second embodiment. In this modified example, the synthetic resin pins 13 are
3b is not formed, and consists only of the shaft portion 13a. Then, horns 502, 502 for forming a head are pressed against both ends of the pin 13 to apply ultrasonic waves, thereby deforming the both ends of the pin 13 so that the head 13b,
13c, the upper and lower hub structures 1
1, 12 are combined. In the embodiment, the case where the ultrasonic welding machine is used to deform the tip of the synthetic resin pin 13 is shown, but a heat welding machine may be used. The other configuration is the same as that of the first embodiment, and the duplicate description will be omitted.

FIG. 9 shows a third embodiment. In this embodiment, a recess 16 for accommodating the head is formed on the lower surface of the bottom surface (chucking surface) 12c of the lower hub assembly 12, and the head 13b of the pin 13 is accommodated in the recess 16; This shows a case where the head 13b does not protrude from the lower surface of the bottom surface (chucking surface) 12c of the lower hub structure 12. The other configuration is the same as that of the first and second embodiments, and the duplicate description will be omitted.

In the embodiment, the case where both the upper and lower hub members 11 and 12 are formed of a magnetic metal plate such as stainless steel or iron is shown. However, the upper hub member 11 is made of PET. (polyethylene terephthalate)
Or a synthetic resin such as polycarbonate. Further, in the embodiment, the case where the upper and lower hub components 11, 12 are connected by three pins 13... 13 at equal angular intervals around the spindle shaft insertion hole 12d is shown. In consideration of the mass balance in the above, the number of pins 13 is not limited to three.

[0029]

The disk of the present invention has the following effects.

(1) The disk according to the first aspect of the present invention is configured such that the upper and lower hub components are connected by pins, and the upper and lower hub components sandwich and support the disk body. When a difference occurs between the thermal expansion amounts of the main body and the upper and lower hub components, slippage occurs between the two, and the disk is displaced as in the case where the center hub of the conventional disk main body is bonded with an adhesive. It is possible to prevent the main body from being warped or deformed, and it becomes a highly reliable product suitable for high-density recording.

(2) In the disk according to the second aspect, since the pins are made of metal, the upper and lower hub components can be securely and firmly connected.

(3) In the disk of the third aspect, since the pins are formed of a synthetic resin, the weight and cost can be reduced as compared with the case where metal pins are used.

(4) In the disk according to the fourth aspect, the head of the pin projects from the lower surface of the bottom surface (chucking surface) of the lower hub assembly and contacts the disk support surface of the turntable of the recording / reproducing apparatus. Can be prevented from becoming unstable.

(5) In the disk according to the fifth aspect, a plurality of pins are arranged at equal angular intervals on the same circumference centered on the spindle shaft insertion hole. Damage can be suppressed.

[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 cross-sectional view of a state where the upper and lower hub components are overlapped.

FIG. 4 is a sectional view showing a state where a pin is inserted.

FIG. 5 is a sectional view of a press device.

FIG. 6 is a cross-sectional view of a state where the components are joined by pins.

FIG. 7 is a sectional view of a main part of the second embodiment.

FIG. 8 is a sectional view of a modification of the second embodiment.

FIG. 9 is a sectional view of a main part of the third embodiment.

FIG. 10 is an exploded perspective view of a conventional example.

FIG. 11 is a sectional view of a use state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disk-shaped recording medium, 2 ... Disk main body part, 2a ...
Center hole, 3 ... Center hub, 11, 12 ... Top and bottom hub structure, 13 ... Pin, 13a ... Shaft, 13b, 13c ...
Head, 16 ... recess for accommodating the head.

Claims (5)

[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 in the above, the center hub is constituted by an upper and lower hub structure which sandwiches the upper and lower surfaces of the recording medium main body, and A disc-shaped recording medium, wherein the lower hub structure is connected by pins for connecting the upper and lower hub structures. 2. The disk-shaped recording medium according to claim 1, wherein the pins for coupling the upper and lower hub members are formed of metal. 3. The disk-shaped recording medium according to claim 1, wherein the pins for connecting the upper and lower hub members are formed of a synthetic resin. 4. The lower hub component according to claim 1, wherein the lower hub component has a recess for accommodating a head portion for accommodating a head portion of a pin for coupling the upper and lower hub components on a bottom surface. Disk-shaped recording medium. 5. The pin according to claim 1, wherein a plurality of pins for coupling the upper and lower hub components are arranged at equal angular intervals on the same circumference centered on a spindle shaft insertion hole provided in the lower hub component. A disk-shaped recording medium characterized by being made.