JPH08235813A - Magnetic disk cartridge - Google Patents

Abstract

PURPOSE: To make a cassette shell light in weight in a magnetic disk cartridge and to improve the productivity and the quality. CONSTITUTION: A recessed part 10 is formed on the inner surface parallel to the magnetic disk 2 of a pair of cassette shell halves 14, and a part of the cassette shell halves 14 is made to be thin. An elastic plate 21 is fixed to the cassette shell half 14 so as to cover the recessed part 10, and a liner 8 is attached to the surface of elastic plate 21 at the side confronted with the magnetic disk 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk cartridge, and more particularly to an improvement of a magnetic disk cartridge having a cassette shell in which a magnetic disk is rotatably contained.

[0002]

2. Description of the Related Art In a magnetic disk cartridge, a magnetic disk for magnetically recording an analog or digital signal is freely rotatable in a thin cassette shell composed of a pair of plastic cassette shell halves which are joined and fixed to each other. The cassette shell, which is built in, has a substantially square upper surface slightly larger than the magnetic disk, a bottom surface having an opening for exposing the center core supporting the center of the magnetic disk, and extends between the upper surface and the peripheral edge of the bottom surface. It is formed in a flat prismatic shape (substantially square shape) consisting of narrow side surfaces. The magnetic disk cartridge is provided with a magnetic head insertion slot into / from which magnetic heads for magnetic recording / reproduction come in and out on both sides of the magnetic disk from the outside or come close to each other. An open / close shutter is provided to prevent dust and the like from entering at the time.

A liner made of non-woven fabric is attached to the inner surface of the cassette shell facing the magnetic disk so that the surface of the magnetic disk is not damaged when the magnetic disk rotates. It is designed to wipe off dust and the like adhering to the.

In recent years, a new high-density recording system has developed a magnetic cartridge having a recording capacity as much as 50 times that of a magnetic cartridge (3.5-inch floppy disk) which has been popular. In such a magnetic cartridge, in order to increase the recording density and the transfer rate, the magnetic disk is rotated at a much higher speed than conventional ones, and at the time of recording / reproducing a signal, an extremely high positional accuracy with respect to the magnetic head is required. Required.

FIG. 5 is a perspective view showing an example of such a high-speed rotation type magnetic disk cartridge, and FIG. 6 is a VI of FIG.
FIG. 6 is a cross-sectional view taken along line VI.

The magnetic disk cartridge 1 comprises a cassette shell 3 which rotatably houses a magnetic disk 2 therein. The cassette shell 3 is formed by plastic molding and is a pair of upper and lower cassette shell halves. It is composed of four and five. On one side of the cassette shell 3, a magnetic recording / reproducing head is attached to the magnetic disk 2.
Magnetic head insertion port 3 for approaching both sides of the
a is provided, and the magnetic head insertion port 3a is provided here.
A shutter member 6 having a U-shaped cross section for opening and closing is attached slidably in a manner biased to a closed position by a spring (not shown). Note that FIG. 3 shows a state (closed position) in which the magnetic head insertion opening 3a is closed by the shutter member 6.

In one cassette shell half 4 located on the lower side in the figure, an opening (circular hole) 4 for exposing a center core 7 for fixing and supporting the center of the magnetic disk 2 is formed.
a is formed, and the inner surface 4b of this cassette shell half 4 is formed.
A doughnut-shaped liner 8 made of a non-woven fabric having a circular hole 8a having a diameter slightly larger than the circular hole 4a is adhered thereto by ultrasonic welding or the like. In addition, a donut-shaped liner 9 made of a non-woven fabric is also provided on the inner surface of the other cassette shell half 5 located on the upper side in the figure with a circular hole 9a for avoiding interference with the flange portion 7a of the center core 7.
Is attached in the same manner as the liner 8.

[0008]

By the way, in such a magnetic cartridge 1, a magnetic head insertion opening 3a is provided on one side surface of the cassette shell 3 so as to be able to face both surfaces of the magnetic disk 2 from the outside. , A recording / reproducing magnetic head is inserted through the magnetic head insertion opening 3a,
Recording and reproduction are performed in the vicinity of the magnetic disk 2 rotating at high speed. Therefore, the cassette shell 3 needs to have a predetermined thickness into which the magnetic head can be inserted.

On the other hand, since the magnetic disk 2 which rotates at a high speed inside the cassette shell 3 is made of a flexible material, it is necessary to suppress the fluttering at the time of rotation.
The internal space of the cassette shell 3 is required to have an appropriate size with high accuracy (generally, a size obtained by adding a slight clearance to the thickness of the magnetic disk 2 and the liners 8 and 9).
In order to realize this dimension with high accuracy, the cassette shell 3 needs to have sufficient rigidity, and for that purpose, the cassette shell 3 needs to have sufficient thickness. For the above reasons, the thickness of the cassette shell 3 is set to the conventional 3.
The thickness of the cassette shell of a 5-inch floppy disc should be twice or more than that of the cassette shell (about 3 mm), and accordingly, the pair of cassette shells which are bonded and fixed to each other to form the cassette shell is required. The thickness of the cassette shell halves 4 and 5 themselves is also considerably thick.

However, the cassette shell having such a thick structure is not only heavy in weight but also requires a large amount of material and a long molding time in manufacturing, which not only causes an increase in cost, but also "Sink" on the thick part
A problem that cannot be overlooked is the adverse effect on quality, which is caused by deformation called "," which deteriorates dimensional accuracy and appearance.

In view of the above circumstances, it is an object of the present invention to reduce the weight of the cassette shell and improve the productivity and quality of the magnetic disk cartridge as described above.

[0012]

In a magnetic disk cartridge according to the present invention, a recess is formed on an inner surface of at least one of the cassette shell halves parallel to the magnetic disk to thin a part of the cassette shell halves. An elastic material is fixed to the cassette shell half so as to cover the recess, and a liner is attached to the surface of the elastic material facing the magnetic disk.

According to one aspect of the present invention, the elastic material may be an elastic plate. In that case, it is preferable to form a stepped portion that supports the peripheral portion of the elastic plate on the peripheral edge of the concave portion on the inner surface of the cassette shell half. And
The elastic plate may be fixed to the cassette shell half in a state of being substantially parallel to the magnetic disk, but the cassette is formed in a state where the central part of the elastic plate is elastically projected toward the magnetic disk side. It may be fixed to the shell half.

In another aspect of the present invention, the elastic plate may be a sponge-like elastic material.

[0015]

Since the magnetic disk cartridge according to the present invention is formed by forming a recess on the inner surface of the cassette shell half to reduce the thickness thereof, the cassette shell is lightened and the molding time is shortened to improve the productivity. The cost can be reduced and the dimensional accuracy inside the cassette shell can be maintained.

Since the liner is attached to the surface of the elastic material, the liner can be elastically brought into contact with the surface of the magnetic disk, and the cleaning effect of the surface of the magnetic disk by the liner can be enhanced.

[0017]

Embodiments of the magnetic disk cartridge according to the present invention will be described below with reference to the accompanying drawings.

1 and 2 show a first embodiment of a magnetic disk cartridge according to the present invention. FIG. 1 is a sectional view corresponding to FIG. 6, and FIG. 2 is an exploded perspective view of a cassette shell without a magnetic disk. It is a figure.

The magnetic disk cartridge 11 comprises a cassette shell 13 which rotatably houses the magnetic disk 2 therein. The cassette shell 13 is formed by plastic molding similarly to the cassette shell 3 shown in FIG. It is composed of a pair of cassette shell halves 14 and 15 which are divided into upper and lower parts.

In one cassette shell half 14 located on the lower side in the figure, a circular opening 1 for exposing a center core 7 for fixing and supporting the central portion of the magnetic disk 2 is provided.
4a is formed, a circular recess 10 is formed on the inner surface of the cassette shell half 14 concentrically with the opening 14a, and the central portion of the cassette shell half 14 forming the bottom surface of the recess 10 is thin. It is a portion 14b. A step portion 10a is formed on the peripheral edge of the recess 10 along the peripheral edge.

The upper surface of the recess 10 is covered with a thin elastic plate 21 made of metal, plastic, or the like, and the peripheral edge of the elastic plate 21 is placed on the stepped portion 10a so that the elastic plate 21 is covered. 21 is fixed to the cassette shell half 14 at its peripheral edge. The elastic plate 21 includes
A circular hole 21a that avoids the center core 7 and a magnetic head insertion notch 21b are formed, and the elastic plate 21 is formed.
A liner 8 of non-woven fabric or the like is attached to the upper surface of the above, that is, to the surface facing the magnetic disk 2. In the liner 8, the circular hole 8a and the magnetic head insertion notch 8 are aligned with the circular hole 21a of the elastic plate 21 and the magnetic head insertion notch 21b.
b is formed so as to come into contact with the surface of the magnetic disk 2 by the elasticity of the elastic plate 21.

On the inner surface of the other cassette shell half 15 located on the upper side, the recess 2 having a diameter substantially the same as that of the recess 10 is also provided.
0 is formed, and the central portion of the cassette shell half 15 forming the top surface of the recess 20 is a thin portion 15a. Further, a step portion 20a is formed in a ring shape along the periphery of the recess 20 as well, and on the step portion 20a,
A peripheral edge of a thin elastic plate 22 made of metal or the like covering the recess 20 is fixed. A liner 9 is attached to the lower surface of the elastic plate 22, that is, the surface facing the magnetic disk 2. The liner 9 includes a flange portion 7 of the center core 7.
A circular hole 9a for avoiding interference with a and a notch 9b for inserting a magnetic head are formed, and the elasticity of the elastic plate 22 makes contact with the surface of the magnetic disk 2.

A circular hole 22a and a magnetic head insertion notch 22b are also formed in the elastic plate 22 so as to match the circular hole 9a of the liner 9 and the magnetic head insertion notch 9b.
The region from the side of the cassette shell half 14 to the recess 10 through the magnetic head insertion opening is also thin so that the magnetic head can be smoothly inserted.

As described above, in this embodiment, the recesses 10 and 20 are formed on the inner surfaces of the cassette shell halves 14 and 15 to reduce the thickness of the cassette shell halves 14 and 15, respectively. The productivity can be improved and the cost can be reduced by shortening the molding time, and the dimensional accuracy inside the cassette shell 13 can be maintained. The recess may be formed on only one of the pair of cassette shell halves 14 and 15, but it is preferable to form the recess on both cassette shell halves 14 and 15 as in the present embodiment.

Further, since the elastic plates 21 and 22 having the liners 8 and 9 attached to the surfaces thereof are provided, good contact between the liners 8 and 9 and the magnetic disk 2 can be maintained, and the magnetic force generated by the liners 8 and 9 can be maintained. The cleaning effect on the surface of the disk 2 can be enhanced.

FIG. 3 is a sectional view corresponding to FIG. 1, showing a second embodiment of the magnetic disk cartridge according to the present invention.

In the magnetic disk cartridge 31 according to this embodiment, the recesses 10 provided on the inner surfaces of the cassette shell halves 14 and 15 which constitute the cassette shell 13,
The step portions 10a and 20a are not formed on the peripheral edge of the elastic plate 20, and the peripheral edge of the elastic plates 21 and 22 are fixed in a state of being engaged with the bottom peripheral edge of the recesses 10 and 20, and the center of the elastic plates 21 and 22 is fixed. The portion elastically projects toward the magnetic disk 2 side to form an arc shape. The peripheral portion of the circular hole 8a of the liner 8 attached to the upper surface of the elastic plate 21 on the lower side in the drawing is the elastic plate 21.
Is pressed against the lower surface of the non-recording area of the magnetic disk 2.

The peripheral portion of the circular hole 9a of the liner 9 attached to the lower surface of the elastic plate 22 on the upper side in the figure is also pressed against the upper surface of the non-recording area of the magnetic disk 2 by the elasticity of the elastic plate 22, and The center portion of the elastic plate 22 that curves downward is in contact with the flange portion 7 a of the center core 7. With such a configuration, the magnetic disk 2 is elastically sandwiched between the liners 8 and 9, and an appropriate braking torque is applied to the rotating portion.

A configuration obtained by further improving the embodiment shown in FIG. 3 is the arrangement shown in FIG. 4, in which the inner surfaces of the cassette shell halves 14 and 15 corresponding to the peripheral edge of the opening 14a exposing the center core 7 are Ring-shaped protrusion 10, 20b
Of the elastic plates 21, 2
The central portions of 2 are supported by ring-shaped projections 10 and 20b, respectively. With such a configuration, the contact with the liners 8 and 9 at the central portion of the magnetic disk 2 is always constant,
It can be ensured that the rotation of the magnetic disk 2 is always constant.

The above is the configuration of the embodiment of the present invention, but the recesses 10 and 20 and the elastic plates 21 and 22 may have not only a circular shape but also a quadrangular planar shape. The liners 8 and 9 can be attached to the elastic plates 21 and 22 by ultrasonic welding, adhesion using an adhesive, adhesion using an adhesive or a UV curing agent, and the like. Further, instead of the elastic plates 21 and 22, a sponge-like elastic material such as urethane foam may be filled in the recesses 10 and 20, and the liners 8 and 9 may be attached to the surfaces of the elastic materials. is there.

[Brief description of drawings]

FIG. 1 is a first magnetic disk cartridge according to the present invention.
Sectional view showing the configuration of the embodiment

FIG. 2 shows a first magnetic disk cartridge according to the present invention.
FIG. 3 is an exploded perspective view showing the configuration of the embodiment of FIG.

FIG. 3 is a second magnetic disk cartridge according to the present invention.
Sectional view showing the configuration of the embodiment

FIG. 4 is a third magnetic disk cartridge according to the present invention.
Sectional view showing the configuration of the embodiment

FIG. 5 is a perspective view of a conventional magnetic disk cartridge.

FIG. 6 is a sectional view taken along line VI-VI in FIG.

[Explanation of symbols]

 2 magnetic disk 7 center core 8,9 liner 10,20 recess 10a, 20a step 10b, 20b ring-shaped protrusion 11 magnetic disk cartridge 13 cassette shell 14, 15 cassette shell half 14a opening 14b, 15b for exposing the center core thin portion 21 , 22 Elastic plate

Claims (6)

[Claims] 1. A cassette shell composed of a pair of cassette shell halves that are rotatably housed in a magnetic disk and are connected to each other, and a magnetic head insertion opening opened and closed by a shutter member is provided on one side surface of the cassette shell. A magnetic disk cartridge provided with an opening for exposing a center core for fixing and supporting the center of the magnetic disk in one cassette shell half, wherein at least one cassette shell half is parallel to the magnetic disk. A recess is formed on the inner surface to thin a part of the cassette shell half, and an elastic material is fixed to the cassette shell half so as to cover the recess, and the elastic material is provided on the side facing the magnetic disk. A magnetic disk cartridge characterized in that a liner is attached to its surface. 2. The magnetic disk cartridge according to claim 1, wherein the elastic material is an elastic plate. 3. The magnetic disk cartridge according to claim 2, wherein a step portion that supports the peripheral portion of the elastic plate is formed on the peripheral edge of the recess. 4. The magnetic disk cartridge according to claim 3, wherein the elastic plate is fixed to the cassette shell half in a state substantially parallel to the magnetic disk. 5. The magnetic according to claim 2, wherein the elastic plate is fixed to the cassette shell half in a state where a central portion of the elastic plate is elastically projected toward the magnetic disk side. Disk cartridge. 6. A ring-shaped projection is provided on the inner surface of each cassette shell half in the portion corresponding to the periphery of the opening exposing the center core so as to project toward the magnetic disk, and the central portion of the elastic plate is The magnetic disk cartridge according to claim 5, wherein the magnetic disk cartridge is supported by the ring-shaped protrusion.