JPH1027452A - Cartridge for recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance welding strength while preventing the occurrence of spaces by welding upper and lower shells, thereby forming a cartridge. SOLUTION: The inside surface of at least one shell of the upper and lower shells 2, 3 is projectingly provided with main welding members 12 and the welding surfaces at the front ends of these main welding members 12 are provided with small projection-like energy directors 7. The welding surfaces at the front end of the main welding members 12 are joined to the other shell by ultrasonic welding in the state of butting the upper and lower shells against each other. At this time, the inside surfaces of the upper shell 2 and lower shell 3 in the positions apart a prescribed distance from the main welding members 12 are respectively projecting provided with auxiliary welding members 16, 26. The front ends of these auxiliary welding members 16, 26 are provided with small projection-like energy directors 8, 8 which are linear and intersect with each other.

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 an upper shell and a lower shell 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 an upper shell and a lower shell made of synthetic resin are joined by ultrasonic welding. However, since the ultrasonic welding does not require a separate bonding material and can be firmly bonded in a short time, it is widely used in a method of bonding a synthetic resin.

When the upper shell and the lower shell are joined by the ultrasonic welding, a welding member and a member to be welded are provided so as to be opposed to the inner surfaces of the upper and lower shells, and the upper and lower shells are joined to the welding surface at the tip of the welding member. It is known that an energy director is provided in the form of a small protrusion and that an energy director is also provided on the end face of the outer peripheral rib, as seen in Japanese Utility Model Laid-Open No. 2-135981.

[0004]

In the above-described cartridge for a recording medium, if dust or the like adheres to the recording medium, it causes dropout and deteriorates the recording quality. Need to be joined so that a gap for dust to enter between them does not occur.

[0005] However, as a cause of the gap between the upper shell and the lower shell, distortion occurs due to the molding accuracy of the upper and lower shells. When the outer peripheral ribs of the upper and lower shells are separated from each other due to deformation, a gap is generated, when the shell is distorted due to dimensional accuracy deviation due to excessive or insufficient welding at the welding member, and a spring for the shutter during assembly. When a component such as the above is inserted into the inside, a force is applied in a direction in which the gap opens, and if the joining force between the upper and lower shells is weak, a gap may be generated. As the recording density of the recording medium increases, the influence of dust on the recording quality further increases, and the possibility of dust entering through a minute gap of about 0.1 mm cannot be ignored.

Further, the above-mentioned gap is generated because the distance between the upper and lower surfaces of the case formed by combining the upper and lower shells is widened. At the same time, the shell surface is rubbed and the shell surface is shaved to generate dust, which may cause poor opening and closing of the shutter member, and may also cause a malfunction when the cartridge is inserted into the disk drive. Have.

[0007] From the above point, the energy director is also installed on the opposite end face of the outer peripheral rib as described above.
If the outer rib is also welded,
When welding is performed properly, it is preferable because the gap can be prevented from being opened. However, in the case of insufficient melting in ultrasonic welding, warpage due to the remaining energy director occurs and the above-described gap is opened. In addition, if the melting is excessive, the molten material may protrude from the outer peripheral ribs to the outside in a burr-like manner. There is a problem that dust is caused by scraping or peeling.

In addition, the upper shell and the lower shell are mainly welded by the welding member and the member to be welded as described above.
It is also conceivable to increase the welding strength or the like by additionally providing a separate welding member at a portion where a gap is likely to be generated and performing welding.

The difference between the functions of the main welding member and the auxiliary welding member will now be described. The main welding member has a function of firmly welding the upper shell and the lower shell, and a function of accurately obtaining the dimensional accuracy of the welded upper and lower shells. Therefore, in order to obtain a sufficient welding size, the energy director is characterized in that the surface to be welded contacts not a point but a line of a certain length. On the other hand, the auxiliary welding member has a function of preventing warpage and deformation of the shell, not from the viewpoint of welding strength or accuracy. Therefore, in the above-described energy director, contact close to point contact with the surface to be welded is sufficient. From this point, the auxiliary welding member has a shape in which a very small part of the energy director contacts as shown in FIGS. 1 and 2 described later.

There is also an idea that the shape of the auxiliary welding member is made the same as that of the main welding member so as to have a function such as securing the strength, that is, two main welding members are provided close to each other. Energy increases, causing a problem of damaging the shell.

However, there is a problem that it is difficult to make the same degree of melting between the main welding member and the auxiliary welding member as described above. In ultrasonic welding, it is possible to apply substantially uniform vibration energy to the portion where the cross-sectional area of the welding horn is projected, but the base material to which the energy is applied may have various irregularities and notches. There is also a portion where the vibration energy is applied is only a part of the base material, so the actual vibration of the base material has a distribution, and generally there is a peak at the center of the projected portion, and the smaller the peripheral portion, the smaller the vibration. Become.

[0012] For these reasons, the molten state varies, or the auxiliary welding member is insufficiently melted due to the above-described variation in molding accuracy or the like, or the projecting dimension of the auxiliary welding member is larger than the main welding member. Occasionally, the auxiliary welding member may rather widen the gap.

Accordingly, the present invention has been made in view of the above circumstances, and has as its object to provide a recording medium cartridge having a welded portion structure in which the welding strength of an upper shell and a lower shell is improved and the generation of a gap is suppressed. .

[0014]

According to the present invention, there is provided a recording medium cartridge having a main welding member protruding from an inner surface of at least one of an upper shell and a lower shell.
A small projection energy director is provided on the tip welding surface of the main welding member and the upper shell and the lower shell are abutted, and the tip welding surface of the main welding member is joined to the other shell by ultrasonic welding. At least one auxiliary welding member protrudes from the inner surface of the upper shell and the inner surface of the lower shell at a position separated from the main welding member by a predetermined amount, and small protrusions linearly and intersecting each other at the tips of the auxiliary welding members. The energy director of the present invention is provided.

Further, when an energy director is formed on the tip welding surface of the main welding member and the upper and lower shells are combined before welding, the height of the energy director of the auxiliary welding member is higher than the height of the energy director of the main welding member. The distance between the tips of the upper and lower auxiliary welding members except for 10 to 300 μm, more preferably 30 to 100 μm, and most preferably 40 to 100 μm.
It is preferable to provide a width of 70 μm.

The shape of the energy director of the main welding member is determined according to the disposition position and the required welding strength. For example, the cross section of the energy director is substantially triangular. The length (width) of the fixed bottom is 10 to 50%, more preferably 20 to 40%, and most preferably 25 to 35% of the width of the tip surface of the main welding member.
Its height (A in FIG. 5) is 0.15 to 0.4 mm, preferably 0.2 to 0.3 mm.

On the other hand, the shape of the energy director provided at the tip of the auxiliary welding member is also substantially triangular in cross section, and the length of the base is smaller than the energy director of the main welding member. 30 to 100% of the base length of the director, more preferably 40 to 8
0%, most preferably 50-70%, the height of which is the same as the energy director of the main welding member.

Further, the degree of intersection between the two auxiliary welding members of the upper and lower shells is as follows.
More preferably, the angle is 30 ° to 90 °, most preferably 45 ° to 90 °, from the viewpoint of stable welding.

[0019]

According to the present invention as described above, when the upper shell and the lower shell are joined by ultrasonic welding by providing the auxiliary welding members having linear energy directors that cross each other. In addition to the main welding by the tip welding surface of the main welding member, the point contact portions of the energy director of the auxiliary welding member that intersect each other are melted with low energy and correspond to the welding height of the main welding member. The upper shell and the lower shell can be ultrasonically welded without gaps due to poor welding, and good gaps can be created against deformation during use and assembling by securing large welding strength. It is possible to suppress the intrusion of dust and to obtain good recording quality, which is suitable for a cartridge that accommodates a recording medium with a high recording density.

In particular, the distance between the tips of the auxiliary welding members is set to 10 to 300 μm based on the height of the energy director of the main welding member.
m, more preferably from 30 to 100 μm, most preferably from 40 to 70 μm, in a welding state in which the energy director of the main welding member is completely melted and the tip welding surface is joined to the mating side, Since the director remains and the tips of the auxiliary welding members do not press against each other, the required welding strength can be obtained without the welded portion of the auxiliary welding member being higher than the main welding member. Can be suppressed.

[0021]

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.

In the magnetic disk cartridge, a disc-shaped recording medium (not shown) is placed 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 using a synthetic resin such as acrylonitrile-butadiene-styrene copolymer. The upper shell 2 has an outer rib 2a in a wall shape around the periphery and an inner rib 2b obliquely on the center side of each corner portion.
An annular rib 2c is provided upright at the center, and a head insertion opening 2d is opened above the annular rib 2c. The lower shell 3 has a peripheral wall rib 3a around the periphery.
An inner rib 3b is formed obliquely at the center side of each corner portion at the same height as the outer peripheral rib 3a, a hub hole 3c for disc drive is opened at the center portion, and a head insertion opening 3d is provided above the hub hole 3c. It is open.

The outer rib 2a and the inner rib 2b of the upper shell 2 and the outer rib 3a and the inner rib 3b of the lower shell 3
Are provided in substantially the same shape, and when the inner surfaces of the upper shell 2 and the lower shell 3 are aligned, the respective outer peripheral ribs 2a, 3a
The inner ribs 2b and 3b are formed so that the opposing end faces 4 and 4 abut in parallel.

As shown in FIG. 3, the ultrasonic welding of the upper shell 2 and the lower shell 3 is performed by using the inner surface of the upper shell 2 and the lower shell 3.
With the upper shell 2 facing downward and the lower shell 3 facing upward, the shell outer surface 3f of the lower shell 3
A cylindrical welding horn 5 is disposed above each of the four corners, and the lower shell 3 is pressed against the upper shell 2 at the tip of the welding horn 5 and ultrasonically excited.

In the vicinity of the four corners on the inner surface of the lower shell 3 (see FIG. 2), first to fourth main welding members 11 to 11 are formed at portions surrounded by the outer ribs 3a and the inner ribs 3b. 14 protrudes from the flat shell inner surface 3e, while the corresponding position of the upper shell 2 (see FIG. 1) corresponds to the portion to be welded corresponding to the portion similarly surrounded by the outer rib 2a and the inner rib 2b. 21 to 24 are protruded. Each of the main welding members 11 to 14 is provided with a concave central portion, and a small projection-like energy director 7 is formed on the entire periphery or a part of the protruding tip welding surface.

Further, in addition to the main welding members 11 to 14, in the vicinity of the second welding member 12, the upper shell 2 and the lower shell 3 at a predetermined distance from the second welding member 12 are provided. Upper auxiliary welding member 1 for performing point welding in an auxiliary manner
6 and a lower auxiliary welding member 26 are formed, and the energy director 8 is provided at the tip thereof. Similarly, in the vicinity of the third welding member 13, the upper shell 2 and the lower shell 3 at positions away from the third welding member 13 by a predetermined amount,
An upper auxiliary welding member 15 and a lower auxiliary welding member 25 for performing point welding in an auxiliary manner are formed, and an energy director 8 is provided at the tip thereof.

Specifically, the lower shell 3 has an annular first main welding member 11 at the upper left in FIG. 2 and the upper shell 2 has a corresponding annular first main welding member at the upper right in FIG. To be welded member 21
Is provided. The lower shell 3 has an annular second main welding member 12 at the lower left in FIG. 2, and the upper shell 2 has a corresponding annular second welding member 22 at the lower right in FIG. Is provided. The lower shell 3 is provided with a third main welding member 13 having an annular shape at the upper right in FIG. 2, and the upper shell 2 is provided with two third protrusions having a rectangular projection at the upper left in FIG. A welding member 23 is provided. The lower shell 3 has an annular fourth main 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.
Is provided.

The first and second annular main welding members 11 and 12 and the corresponding annular first and second members to be welded 21 and 22 are substantially equivalent to each other. Are formed at substantially the same heights as the outer ribs 2a, 3a and the inner ribs 2b, 3b, respectively. The two end welding surfaces are welded in abutting manner via the energy director 7.

The third welded member 2 having a square shape of the upper shell 2
The third main welding member 13 and the member to be welded 23 are both higher than the outer peripheral ribs 2a, 3a. The energy director 7 is formed to project from arcuate portions on both sides of the distal end surface of the third main welding member 13, and the distal end surface can be brought into contact with the shell inner surface 2 e of the upper shell 2 and is welded to this portion. The outer surface of the third member to be welded 23 comes into contact with the inner surface of the third main member 13 to be welded.

The annular fourth welded member 24 of the upper shell 2 is connected to the annular fourth main welded member 14 of the lower shell 3.
The height of both is provided higher than the outer circumferential ribs 2a, 3a, and the energy director 7 projects partially in a circular arc shape from the distal end surface of the fourth main welding member 14. The surface can be brought into contact with the shell inner surface 2e of the upper shell 2 and is welded to this portion, and the outer peripheral surface of the fourth welded member 24 comes into contact with the inner peripheral surface of the fourth main welded member 14 and is welded. You.

The structure of upper and lower auxiliary welding members 16 and 26 for performing auxiliary point-like welding, which are installed near the second main welding member 12 and the member to be welded 22, are shown in FIGS. Will be explained. First, an energy director 7 having a triangular cross section is provided at the center of the front end welding surface of the second main welding member 12, and the energy director 7 of the second welded member 22 which is provided at the upper shell 2 in correspondence therewith is provided. The energy director 7 is pressed against the front end surface, and is completely melted.
Is welded to the tip surface of the member to be welded 22 in a press-contact state.

At the position of the lower shell 3 near the second main welding member 12 and shifted to the center side along the lateral side, two lower auxiliary welding members 16 projecting in a plate shape are erected. The lower auxiliary welding member 16 is formed to extend in the front-rear direction in parallel with the vertical side, and a linearly extending energy director 8 is formed at a tip portion thereof. On the other hand, at the corresponding position of the upper shell 2 near the second member 22 to be welded and shifted toward the center along the horizontal side, an upper auxiliary welding member 26 protruding in a flat plate shape is provided upright. The upper auxiliary welding member 26 is formed so as to extend in the left-right direction in parallel with the horizontal side and intersect with the lower auxiliary welding member 16, and a linearly extending energy director 8 is similarly formed at a tip portion thereof. The energy directors 8, 8 of the upper and lower auxiliary welding members 16, 26 are provided in the same triangular cross-section as the energy directors 7 formed on the main welding members 11 to 14, and have substantially the same height. ing.

The height of the upper and lower auxiliary welding members 16 and 26 is
As shown in FIG. 5, when the upper and lower shells 2 and 3 are combined before welding, the energy director 8 in the upper and lower auxiliary welding members 16 and 26 is higher than the height A of the energy director 7 of the second main welding member 12. The distance B between the tips of the upper and lower auxiliary welding members 16 and 26 excluding the height of.
m, more preferably 30 to 100 μm, and most preferably 40 to 70 μm.

With this, in a state where the energy director 7 of the main welding member 12 is completely melted and the main welding member 12 and the tip of the member 22 to be welded are welded to each other,
The energy directors 8, 8 of the upper and lower auxiliary welding members 16, 26 are always in contact with each other and are spot-welded, and the energy director 8 does not melt at all heights.
The above dimensions are set so that the tips of the upper and lower auxiliary welding members 16 and 26 do not contact each other. As a result, it is possible to avoid that the welding height of the auxiliary welding members 16 and 26 becomes higher than the welding height of the main welding member 12 and the member 22 to be welded, that is, from the press-contact positions of the upper and lower outer peripheral ribs 2a and 3a. The upper and lower outer peripheral ribs 2a and 3a are separated from each other to prevent a gap from being generated.

The planar formation positions of the auxiliary welding members 16 and 26 are determined according to the relationship with the shape of the welding horn 5 and the like. As described above, since the ultrasonic energy has a distribution, the second Except for an adjacent portion that is excessively melted by the ultrasonic energy required for welding the welding member 12, and a portion far from the contact range of the welding horn 5 except that the ultrasonic vibration is weak and melting does not occur, so that an appropriate supersonic wave is generated. It is set in a region where melting occurs due to sonic vibration and welding occurs. For example, in the case of a welding horn 5 having a diameter of about 20 mm,
5 from the center of the second main welding member 12 (the dashed line in FIG. 3).
mm or more, preferably 10 mm or more, but not more than 15 mm (the dashed line in FIG. 3). The distance between the upper auxiliary welding members 16 and 16 (d in FIG. 3) is
It is good to be 1-5 mm, preferably 2-4 mm.

In the vicinity where a sufficient bonding strength is obtained by welding of the main welding member 12, the auxiliary welding members 16 and 26 need not be installed, and the welding is performed at a position separated by a predetermined distance from this point. To do.

As for the auxiliary welding members 15 and 25 near the third welding member 13, the above-mentioned auxiliary welding members 16 and 25 are also used.
It is configured in the same way as 26.

The auxiliary welding members 15, 25, 1 as described above
6 and 26 may be installed at other corners, and are indicated by chain lines in FIG. 1 and FIG.
Is shown.

The welding horn 5 has a divided structure corresponding to each corner portion as an example. However, the entire outer surface 3f of the lower shell 3 may be pressed by one large integrated welding horn. In this case, the portion where the auxiliary welding member can be installed is changed in conformity with this. However, basically, the auxiliary welding member is arranged in a portion where the above-mentioned gap easily occurs.

The shape of the auxiliary welding member can be appropriately changed as long as it performs point welding. If the energy directors of the upper and lower auxiliary welding members are linear and intersect with each other, either a straight line or a curved line can be used. Shape. Further, the number of spot welds is not limited to the two shown, but may be set to one or three or more in accordance with the required welding strength.

[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 a sectional view of a main part taken along line XX of FIG. 3;

FIG. 5 is a sectional view showing a dimensional relationship in a state where the upper and lower shells are combined.

[Explanation of symbols]

 2 Upper shell 3 Lower shell 2a, 3a Outer rib 2e, 3e Inner rib 5 Welding horn 7, 8 Energy director 11-14 Main welding member 21-24 Welding member 15, 25, 16, 26 Auxiliary welding member

Claims (2)

[Claims] 1. A main welding member protrudes from an inner surface of at least one of an upper shell and a lower shell, and a small projection-like energy director is provided on a front welding surface of the main welding member to abut the upper shell and the lower shell. In a recording medium cartridge in which the tip welding surface of the main welding member is joined to the other shell by ultrasonic welding in a state where the upper and lower shells are separated by a predetermined amount from the main welding member, A recording medium cartridge comprising at least one auxiliary welding member projecting therefrom, and small projecting energy directors linearly intersecting with each other at the tips of the auxiliary welding members. 2. An energy director is formed on the tip welding surface of the main welding member, and when the upper and lower shells are combined before welding, the height of the energy director of the main welding member is higher than the height of the energy director.
2. The recording medium cartridge according to claim 1, wherein the distance between the tips of the upper and lower auxiliary welding members except for the height of the energy director is set wider by 10 to 300 [mu] m.