JPH1021665A - Cartridge for recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent intrusion of dust by joining the outer circumferential ribs of upper and lower shells appropriately with no burr being accompanied at the time of forming a cartridge by welding the upper and lower shells. SOLUTION: A welding member 11 is projected from the inner surface of at least one of upper and lower shells 2, 3 provided with wall-like outer circumferential ribs 2a, 3a. When the welding member 11 is joined to the other shell by ultrasonic welding while butting the outer circumferential ribs 2a, 3a of the upper and lower shells 2, 3 to each other, the outer circumferential ribs 2a, 3a of the upper and lower shells 2, 3 are formed into steps having vertical joint faces 4a, 5a touching the end faces 4, 5 vertically. At the same time, the vertical joint face 5a of the outer circumferential rib 3a of at least one shell 3 is roughened.

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. It is necessary to join them together without generating a gap for dust to enter between them, and to perform ultrasonic welding so as to prevent protrusions such as burrs from being generated at the joints.

[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. Due to deformation, when the outer peripheral ribs of the upper and lower shells are separated from each other and a gap is generated, or there is a case where distortion occurs in the shell due to dimensional accuracy deviation due to excessive or insufficient welding with the welding member, etc. When the recording density of the recording medium increases even if a minute gap is generated, the influence of dust becomes severe, and the recording quality is reduced.

In view of the above, an 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 view of the above circumstances, the present invention provides a recording medium cartridge having a welded portion structure in which the outer peripheral ribs of an upper shell and a lower shell are appropriately joined without burrs to suppress generation of a gap. It will not be provided.

[0008]

According to the recording medium cartridge of the present invention which has solved the above-mentioned problems, a welding member is provided on the inner surface of at least one of an upper shell and a lower shell having peripheral ribs in the shape of a wall around the recording medium. Then, in a state where the outer peripheral ribs of the upper shell and the lower shell abut each other, the welding member is joined to the other shell by ultrasonic welding,
Peripheral ribs of the upper shell and the lower shell are provided in a stepped shape having a joining vertical surface in which the height of the facing end surface changes in the middle and is perpendicular to the end surface and connected to each other, and at least one of the upper shell and the lower shell. The joining vertical surface of the outer peripheral rib is formed to be a rough surface.

The average surface roughness Rz of the rough surface is 5 to 5.
The thickness is preferably 100 μm, preferably 10 to 70 μm, more preferably 20 to 40 μm. Further, in a state where the stepped outer peripheral ribs of the upper shell and the lower shell abut against each other, the gap between the end faces of the outer ribs of the upper shell and the lower shell on the outer peripheral surface is 10 to 200 μm, preferably 3 μm.
It is desirable to set it at 0 to 100 μm, more preferably at 50 to 80 μm.

When the outer peripheral ribs of the upper and lower shells are welded to each other by the rough joining vertical surface, the sealing performance is improved to prevent dust from entering, and the gap is hardly opened when the cartridge is deformed. However, the bonding strength is not required to be large, and the main bonding strength is obtained by the welding member, and it is sufficient if the strength is sufficient to simply prevent the opening of the gap.

[0011]

According to the present invention as described above, the outer peripheral ribs of the upper shell and the lower shell are provided in a stepped shape having a joining vertical surface that comes into contact with each other, and the joining vertical surface of at least one of the outer peripheral ribs is roughened. When the upper and lower shells are joined by ultrasonic welding, the main welding is performed by melting the welded portion of the welding member, and the outer surface of the outer rib is roughened by excessive vibration energy. The surfaces are lightly welded, and the outer peripheral ribs of the upper and lower shells are joined together to suppress the generation of gaps, prevent intrusion of dust, obtain good recording quality, and accommodate recording media with high recording density. This is suitable for a cartridge that performs the following operations.

Further, since the welding portion of the outer peripheral rib is a rough surface, the energy required for welding may be small, and
Even if it is not welded, the shell does not warp and does not cause any gaps.Because of the stepped shape, it basically has excellent sealing performance and prevents dust from entering. However, even if the melting of this portion is somewhat excessive on a vertical surface, burrs are hardly generated on the outer surface, which is advantageous in appearance and generation of dust.

Further, when the average surface roughness Rz of the rough joining vertical surface is set to 5 to 100 μm, a good welding state can be obtained. The lower the surface roughness, the more difficult it is to weld, and the more favorable the ultrasonic vibration.

Further, when a gap of 10 to 200 μm is provided between the end faces of the outer peripheral surface of the stepped outer peripheral rib, the melt does not flow to the outside while the gap is filled with the molten material, and the generation of burrs can be suppressed.

[0015]

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 of a magnetic disk cartridge as an example of a recording medium cartridge, and FIG. 2 is an inner view of the lower shell.

In the magnetic disk cartridge, a disk-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 ultrasonic welding of the upper shell 2 and the lower shell 3 is performed by, as shown in FIG.
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 6 is disposed above each of the four corners, and ultrasonic vibration is applied while the lower shell 3 is pressed against the upper shell 2 at the tip of the welding horn 6.

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 the end faces 4, 5 of the outer peripheral ribs 2a, 3a facing each other are provided in a stepped shape.

The stepped shapes of the outer peripheral ribs 2a and 3a are as follows.
As shown in FIG. 3 and FIG.
The opposite end surface 4a is higher on the inner peripheral side and lower on the outer peripheral side, and the middle vertical joining surface 4a is formed facing outward. The opposite end face 5 of the outer peripheral rib 3a of the lower shell 3 is lower on the inner peripheral side and higher on the outer peripheral side, and the intermediate joining vertical surface 5a is formed inward.

When the outer rib 2a of the upper shell 2 and the outer rib 3a of the lower shell 3 abut against each other, the dimensions are set so that the joining vertical surfaces 4a, 5a of the outer ribs 2a, 3a are in contact. In practice, the outer circumferential ribs 2a,
Reference numeral 3a denotes a thin structure, which may be brought into contact with an elastically deformed structure. The joining vertical surface 5a of the outer rib 3a of the lower shell 3 has an average surface roughness Rz of 5-10.
0 μm, preferably 10-70 μm, more preferably 2 μm
It is formed on a rough surface of 0 to 40 μm.

Also, after welding the upper shell 2 and the lower shell 3, the joining vertical surfaces 4a, 5a of the two outer ribs 2a, 3a are joined.
The contact portion has a length h (see FIG. 4) of 0.1 to 5 mm, preferably 0.3 to 1.5 mm, more preferably 0.5 to 5 mm.
0.8 mm.

Further, the outer peripheral ribs 2a, 3a as described above
In the stepped shape shown in FIG. 4, in a state where the welding is completed as shown in FIG. 4 or in a state where the upper shell 2 and the lower shell 3 are combined for welding, the outer peripheral ribs 2a and 3 of the both are provided.
a, the end face 4 of the outer rib 2a of the upper shell 2 and the end face 5 of the outer rib 3a of the lower shell 3 on the outer peripheral surface.
Between 10 and 200 μm, preferably between 30 and 100 μm
m, more preferably 50 to 80 μm.

In the vicinity of the four corners on 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 is provided with an annular first welding member 11 at the upper left in FIG. 2, and the upper shell 2 is correspondingly provided with an 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.

And, 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 The energy directors 7 are provided at substantially the same height as the inner ribs 2b, 3b, and the welding members 11, 12, 13, 15 are provided with annular energy directors 7 at the leading end surfaces thereof. Are welded in a butted state.

Specifically, as shown in FIG. 3, an 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, and the energy director 7 is provided at the upper shell 2 in correspondence thereto. The first welded member 21 thus welded is pressed against and welded to the end face 21a.

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 set to the inner ribs 2 b, 3 b. 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. And the outer peripheral surface of the fourth member 24
Is brought into contact with the inner peripheral surface of the welding member 14 to be welded.

The outer ribs 2a, 3a of the upper shell 2 and the lower shell 3 are provided in a stepped shape over the entire circumference (excluding the opening), and the joining vertical surface 5a of the outer rib 3a of the lower shell 3 is It is formed on a rough surface all around.
The joining vertical surface 4a of the upper shell 2 is provided on a smooth surface.

The joining vertical surface 5a of the outer peripheral rib 3a may be partially roughened instead of the entire circumference, and the range of the roughening is determined by the relationship with the shape of the welding horn 6 and the like. Except for the portion that is excessively melted by the ultrasonic energy required for welding the welding members 11 to 15, and in the portion far from the contact area of the welding horn 6, the ultrasonic vibration is weak and melting does not occur. May be formed only in a region where a slight melting occurs due to the ultrasonic vibration and a light welding is performed. Also, the stepped shapes of the outer peripheral ribs 2a and 3a may be provided only in portions where welding is required.

Also, the joining vertical surface 5a of the outer peripheral rib 3a
The rough surface can be formed by roughening the surface of a molding die for molding the lower shell 3 by a known means such as electric discharge machining, machining, etching or the like.

The joining vertical surface 4 of the outer peripheral ribs 2a, 3a
In a and 5a, it is preferable that the outer peripheral rib 3a of the lower shell 3 on the side where the tip of the welding horn 6 comes into contact is provided on a rough surface, but the joining vertical surfaces 4a and 5a of the outer peripheral ribs 2a and 3a are made rough. It may be formed, or only the joint vertical surface 4a of the upper shell 2 on the opposite side may be formed with a rough surface.

Although the welding horn 6 has a divided structure corresponding to each corner portion as an example, the welding horn 6 may be such that the entire outer surface 3f of the lower shell 3 is pressed by one large integrated welding horn. In this case, in this case, it is preferable to form the shell on a rough surface over the entire circumference.

Further, the weldability differs depending on the degree of the rough surface of the above-mentioned vertical joint surface, and the average surface roughness Rz is 5 to 100.
It is formed to a thickness of about μm, the larger the surface roughness is, the easier the welding is, and it is suitable for a portion where ultrasonic vibration is weak, and the smaller the surface roughness is, the less it is hard to be welded, and it is suitable for a portion where ultrasonic vibration is strong. Therefore, the surface roughness of the rough surface may be changed in accordance with the intensity of the ultrasonic vibration acting on each part in consideration of the form of the welding horn and the like.

[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 after welding.

[Explanation of symbols]

 2 Upper Shell 3 Lower Shell 2a, 3a Outer Rib 2e, 3e Inner Rib 4, 5 End Face 4a, 5a Joining Vertical Face 6 Welding Horn 7 Energy Director 11-15 Welding Member 21-25 Welding Member

Claims (3)

[Claims] A welding member protrudes from an inner surface of at least one of an upper shell and a lower shell having peripheral ribs in a wall shape around the outer shell, and the outer ribs of the upper shell and the lower shell abut against each other. In a recording medium cartridge in which the welding member is joined to the other shell by ultrasonic welding, the outer ribs of the upper shell and the lower shell are formed such that the heights of opposed end faces change halfway and are perpendicular to the end faces. A cartridge for a recording medium, wherein the cartridge is provided in a stepped shape having a joining vertical surface that comes into contact, and a joining vertical surface of at least one outer peripheral rib of an upper shell and a lower shell is formed as a rough surface. 2. An average surface roughness Rz of the rough surface is 5-10.
The recording medium cartridge according to claim 1, wherein the thickness is 0 μm. 3. A gap between end faces of the outer ribs of the upper shell and the lower shell on the outer peripheral surface in a state where the stepped outer ribs of the upper shell and the lower shell abut against each other.
The recording medium cartridge according to claim 1, wherein the thickness is μm.