JPH1021666A - Cartridge for recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of dust due to reduction of ultrasonic output while ensuring a rigid and reliable welding without causing any gap between shells by paying attention to the amplitude characteristics of ultrasonic welding at the time of forming a cartridge by welding upper and lower shells. SOLUTION: The tip face 11a of a welding member 11 projecting from the inner surface 3e of a least one of upper and lower shells 2, 3 to be welded ultrasonically is provided with an energy director 7 in the form of a small protrusion. At the same time, the cross-section in the direction perpendicularly intersecting the projecting direction of the tip face of the welding member 11 is set smaller than the cross-section at a base part 11b being jointed to the inner face 3e of the shell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium cartridge for accommodating a disk-shaped recording medium in which upper and lower shells are joined by ultrasonic welding, and more particularly to a structure of a welded portion thereof.

[0002]

2. Description of the Related Art For example, a magnetic disk cartridge as a recording medium cartridge has a flexible magnetic disk rotatably housed in a case in which upper and lower shells made of synthetic resin are joined by ultrasonic welding. The ultrasonic welding does not require a separate bonding material and can be firmly bonded in a short time.

When the upper and lower shells are joined by ultrasonic welding, a welding member and a member to be welded are provided so as to face each inner surface of the upper and lower shells, and a small projection is formed on the welding surface at the tip end of the welding member. It is known to provide an energy director in a vehicle, for example, as seen in U.S. Pat.

[0004]

In the above-described cartridge for a recording medium, if dust or the like adheres to the recording medium, it causes a dropout and deteriorates the recording quality. There is no gap between shells for dust to enter,
It is necessary to reduce dust generation during ultrasonic welding.

More specifically, in ultrasonic welding, ultrasonic waves are applied while pressing the welding horn against the outer surface of the shell from above and below the upper and lower shells, and the energy of the vibration is used to melt the energy director at the tip of the welding member. The energy director is intended to reduce the ultrasonic output required for welding.

However, in the ultrasonic welding described above,
A portion of the shell vibrated by the ultrasonic vibration, for example, a welding portion at the tip of the welding member, an outer surface portion where the welding horn comes into contact, and the like, a part of the shell is shaved to generate powdery dust, which is an internal disk housing portion. In addition to the above, there is a problem that the recording quality is deteriorated when penetrating into the shell, and a contact mark of the welding horn is left on the outer surface of the shell, thereby lowering the commerciality.

[0007] From the above point, it is preferable that the ultrasonic output applied for welding is as low as possible, since the generation of dust can be reduced. However, if the welding of the welding member is insufficient, shell peeling may occur. There is a problem of intrusion of external dust due to the generation of a gap, and the ultrasonic energy required for welding changes due to a dimensional error of the welding member or other parts. The ultrasonic output is applied, and this causes the dust and shell surface properties as described above.

Although the above-mentioned energy director improves the weldability and contributes to the reduction of the ultrasonic output, further reduction is required. In particular, when the recording density of the recording medium is increased, the influence of dust becomes severe, and the energy is further reduced. It is desired to remove dust.

In view of the above circumstances, the present invention focuses on the amplitude characteristics of ultrasonic welding, and suppresses the generation of dust due to a reduction in ultrasonic output while ensuring strong and reliable welding without the occurrence of shell gaps. It is an object of the present invention to provide a recording medium cartridge having the above-described welded portion structure.

[0010]

A recording medium cartridge according to the present invention which has solved the above-mentioned problems has a welding member projecting from the inner surface of at least one of the upper and lower shells to be ultrasonically welded. A small protrusion-shaped energy director is provided on the welding surface, and a cross-sectional area of a base portion coupled to the shell inner surface is formed to be larger than a cross-sectional area in a direction orthogonal to a protruding direction of a tip portion thereof. Things.

More specifically, it is preferable that a connecting portion between the side surface of the welding member and the inner surface of the shell is formed by a curved surface having a radius of 0.2 mm or more, so that a cross-sectional area of a base portion is larger than that of a tip portion. Alternatively, a structure in which a side surface of the welding member is provided on a tapered surface or a curved surface, and a cross-sectional area orthogonal to a protruding direction is gradually increased from a distal end portion toward a base portion connected to the shell inner surface, or a shell. A tapered structure (a so-called chamfered structure) may be provided in the vicinity of the base portion coupled to the inner surface.

[0012]

According to the present invention as described above, the cross-sectional area orthogonal to the projecting direction of the welding member projecting from the inner surface of the shell is defined as:
By providing the base portion coupled to the inner surface of the shell to be larger than the tip portion where the energy director is formed, the ultrasonic energy can be absorbed in a wide range and the portion where the amplitude of the ultrasonic vibration becomes maximum is reduced by the energy director. Position, so that welding can be performed at a lower output, dust generation from the ultrasonic vibration parts such as the welding part and the shell surface is reduced, and crushing and deformation of the peripheral ribs and the like that must not be melted are prevented. It can be made small and strong welding without shell gap can be performed. In addition, a wide range of the contact area of the welding horn can be used more effectively by improving the strength of the welding member as the cross-sectional area of the base increases, so that the surface roughness due to the shaving of the shell surface and the like is reduced, and the commercial value is improved.

In particular, in a cartridge containing a high recording density medium, the generation of dust during ultrasonic welding is reduced, and
By forming a cartridge having no shell gap by reliable welding that does not cause the outer ribs to be crushed or deformed, it is possible to prevent dust from entering from the outside and improve the recording quality.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an inner view of an upper shell in a magnetic disk cartridge as an example of a recording medium cartridge, FIG. 2 is an inner view of the lower shell, and FIG. 3 is a cross-sectional view of a principal part explaining a process of ultrasonic welding.

The magnetic disk cartridge comprises a disc-shaped recording medium (not shown) in a flat case in which the upper shell 2 of FIG. 1 and the lower shell 3 of FIG. A magnetic disk medium is rotatably accommodated, and a liner is interposed between the recording medium and the inner surface of the shell.

The upper shell 2 and the lower shell 3 are formed into a substantially rectangular flat plate by using a synthetic resin such as an acrylonitrile-butadiene-styrene copolymer. In the upper shell 2, an outer rib 2a is formed around the periphery, an inner rib 2b is formed obliquely at the center side of each corner at the same height as the outer rib 2a, and an annular rib 2c is erected at the center. The head insertion opening 2d is opened upward. In the lower shell 3, an outer rib 3a is formed around the periphery, and an inner rib 3b is formed obliquely at the center of each corner portion at the same height as the outer rib 3a.
c is opened, and a head insertion opening 3d is opened above it.

The ultrasonic welding of the upper shell 2 and the lower shell 3 is performed by, as shown in FIG.
With the upper shell 2 down with the inner surfaces of
The lower shell 3 is placed in an upper state, and cylindrical welding horns 5 are respectively arranged above the four corners of the shell outer surface 3f of the lower shell 3, and the lower shell 3 is raised at the tip of the welding horn 5. Ultrasonic vibration is applied while pressing the shell 2.

In the vicinity of the four corners of the inner surface of the lower shell 3 (see FIG. 2), the welding members 11 to 15 are provided with a flat shell inner surface 3e at a portion surrounded by the outer peripheral rib 3a and the inner rib 3b. More protruding, while upper shell 2
At the corresponding position (see FIG. 1), similarly, members to be welded 21 to 25 are protruded from a portion surrounded by the outer rib 2a and the inner rib 2b. A central portion of the welding members 11 to 15 is provided so as to be recessed at substantially the same height as the inner surface 2e of the shell, and a small-projection-shaped energy director 7 is formed on the entire periphery or a part of the protruding tip surface. .

Specifically, the lower shell 3 has an annular first welding member 11 at the upper left in FIG. 2, and the upper shell 2 has a corresponding annular first welding member at the upper right in FIG. A member to be welded 21 is provided. The lower shell 3 has an annular second welding member 12 at the lower left in FIG. 2, and the upper shell 2 has an annular second welding member 22 at the lower right in FIG. Provided. The lower shell 3 has an annular third ring at the upper right in FIG.
The upper shell 2 has a welding member 13 corresponding to FIG.
Thus, an annular third welded member 23 is provided at the upper left.
The lower shell 3 has an annular fourth welding member 14 at the lower right in FIG. 2, and the upper shell 2 has a corresponding annular fourth welding member 24 at the lower left in FIG. Provided. Further, a small annular fifth welding member 15 is provided on the lower shell 3 in the vicinity of the third welding member 13 on the upper right in FIG. 2, and the upper shell 2 is correspondingly located on the upper left in FIG. In the vicinity of the third welded member 23, a small annular fifth welded member 2 is
5 are provided.

The first, second, third and fifth
Welding members 11, 12, 13, 15 formed in an annular shape
And the corresponding first, second, third, and fifth annularly formed members to be welded 21, 22, 23, and 25 are formed to have substantially the same outer shape and inner diameter, and Each of the welding members 11, 12, 13, 15 is provided at substantially the same height as the outer ribs 2a, 3a and the inner ribs 2b, 3b.
An energy director 7 protrudes annularly from the tip surface of
Both end welding surfaces are welded in abutting state via the energy director 7.

The annular fourth welded member 24 of the upper shell 2 can be inserted into the annular fourth welded member 14 of the lower shell 3, and the height of both members is equal to the outer peripheral ribs 2a, 3a. The energy director 7 is protruded from the tip end surface of the fourth welding member 14 in a partially arcuate shape, and this tip end surface can be brought into contact with the shell inner surface 2e of the upper shell 2 and welded to this portion. At the same time, the outer peripheral surface of the fourth welded member 24 comes into contact with the inner peripheral surface of the fourth welded member 14 and is welded.

The cross-sectional shape of the first to fifth welding members 11 to 15 having the energy director 7 formed on the front end surface is a cross section in a direction perpendicular to the projecting direction of the front end where the energy director 7 is formed. The cross-sectional area of the base portion coupled to the shell inner surface 3e is larger than the area.

That is, if the first welding member 11 is shown in FIGS. 3 and 4 as an example, the energy director 7 having a triangular cross section is provided at the center of the front end surface 11a of the first welding member 11.
A connecting portion of the base portion 11b from which the both side surfaces 11c are joined to the shell inner surface 3e from the front end surface 11a is provided on a curved surface R having a radius of 0.2 mm or more. It is formed to be large.

Strictly speaking, the curved surface R originally has an arcuate surface shape (R shape), but from the viewpoint of proper transmission of ultrasonic energy to the energy director 7, its radius is 0.2 mm or more. Otherwise, there is no substantial effect, and the radius may be set to be the same as the height t of the welding member 11 or may be set to a larger radius to increase the cross-sectional area of the base 11b.

The side surface of the base of the member to be welded 21 may be formed in a curved shape. The shape of the energy director 7 is determined according to the required welding strength that differs depending on the disposition position. For example, if the cross-sectional shape is substantially triangular and the material is ABS resin or PS resin, The length W1 of the base (see FIG. 4) is set to 10 to 50%, preferably 20 to 40%, more preferably 25 to 35% of the width W of the distal end surface 11a of the welding member 11, and its height is set. h is 20 to 200%, preferably 40 to 100%, more preferably 60 to 80% of the base length W1.
Set to.

FIG. 5 shows a different shape of the welding member 11 (other welding members 12 to 15 may be similarly formed).
A similar energy director 7 protrudes from the end surface 11a, and both side surfaces 11c are provided on the tapered surface from the front end surface 11a.
It is formed so as to increase gradually and continuously toward the base 11b to be connected to e. In the tapered shape, the width D2 of the base 1b is D2 = D2 = the width D1 of the tip end surface 11a.
1.1-4.0 D1, preferably D2 = 1.6-2.
Set to be 5D1.

The connection between the tapered side surface 11c of the welding member 11 and the inner shell surface 3e is shown in FIG.
It is preferable to form a curved surface as shown by a chain line in FIG. The side surface 11c may be formed by a curved surface such as a parabola instead of the tapered surface, and may be provided so that the cross-sectional area gradually increases from the distal end surface 11a toward the base 11b.

FIG. 6 shows a further different shape of the welding member 11.
A similar energy director 7 protrudes from 1a, and is provided on the tapered surface C only in the vicinity of the base 11b on both side surfaces 11c.
The base 11b is formed so as to have a large cross-sectional area perpendicular to the protruding direction. The height of the tapered surface C is 0.05 to 1.0 mm, preferably 0.1 to 0.6 m.
m, more preferably 0.2 to 0.5 mm.

As described above, the cross-sectional shapes of the welding members 11 to 15 are provided so as to be larger at the base portion connected to the shell inner surface 3e than at the distal end portion, so that the cross-sectional areas are the same. Then, while the amplitude of the ultrasonic vibration applied from the welding horn 5 tends to gradually decrease toward the tip, the ultrasonic energy is reduced by the large cross-sectional area of the portion near the welding horn 5. Since energy can be efficiently absorbed and the so-called antinode of the ultrasonic vibration waveform is located at the position of the energy director 7, the energy director 7 vibrates efficiently, and the energy director 7 melts and acts like a bonding material. Counterpart (welded member 2
1 to 25 or the inner surface 2e) of the upper shell.

If there are corners (steps) in the side surface shape of the welding members 11 to 15, the load concentration occurs at these portions, so that the welding members 11 to 15 are provided in a shape that changes gently so that such concentration does not occur. It is preferable to adopt a structure that concentrates on the energy director 7.

Further, since the joining area of the welding members 11 to 15 is increased and its strength is increased, a wide range of ultrasonic energy can be effectively used for the welding horn 5, and the energy can be used as described above. Ultrasonic output can be reduced by concentrating and welding to the director 7.

[Brief description of the drawings]

FIG. 1 is an inner view of an upper shell of a magnetic recording cartridge as a recording medium cartridge according to one embodiment of the present invention.

FIG. 2 is an inner view of a lower shell of the magnetic recording cartridge.

FIG. 3 is a sectional view of an essential part for explaining an ultrasonic welding process.

FIG. 4 is an enlarged view of a welding member in FIG. 3;

FIG. 5 is an enlarged view showing another example of the shape of the welding member;

FIG. 6 is an enlarged view showing still another example of the shape of the welding member;

[Explanation of symbols]

 2 Upper shell 3 Lower shell 2a, 3a Outer rib 2e, 3e Inner rib 3f Outer surface 5 Welding horn 7 Energy director 11-15 Welding member 11a Tip surface 11b Base 11c Side surface 21-25 Welded member

Claims (1)

[Claims] 1. A recording medium cartridge in which a small-projection energy director is provided on a tip welding surface of a welding member protruding from an inner surface of at least one of an upper shell and a lower shell joined by ultrasonic welding. A recording medium, wherein the welding member is formed such that a cross-sectional area of a base portion coupled to an inner surface of the shell is larger than a cross-sectional area in a direction orthogonal to a protruding direction of a tip portion on which an energy director is formed. For cartridges.