JPH09298790A - Sound collection cover for acoustic equipment and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost and to prevent production of a rattle sound. SOLUTION: A sound collection cover 3 provided with a sound collection microphone and fitted to an acoustic equipment casing made of a 1st resin is made up of a sound collection cover main body 8 made of a 2nd resin and having lots of sound collection holes and a packing 9 adhered to an inner face of the sound collection cover main body 8 through integral forming, made of a 3rd resin and whose outer face is overlapped with the sound collection cover main body 8. The 1st resin forming the inner layer and the 2nd resin forming the outer layer are harder than an elastomer being the 3rd resin forming the medium layer, the outer layer and the medium layer are fused and the inner and outer layers are made of the same resin and production of rattle sound is prevented by making the natural frequency homogeneous in the inner and outer layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound collector cover for an audio device and a method for manufacturing the same. More specifically, the present invention relates to a sound collector cover of an audio device such as a video camera having a sound collector located in the front portion, and a method for manufacturing the same.

[0002]

2. Description of the Related Art An audio device such as a video camera has a sound collecting portion formed at the front. The structure of the sound collecting unit is designed in consideration of directivity, muffled sound, and sound collecting ability. The sound collector cover that protects the built-in microphone is detachable from the casing body of the audio device. Sound collection cover 01
As shown in FIG. 7, a large number of small sound collection holes 02 are opened in the. The aperture ratio is as high as 60%. The sound collector cover 01, which has such a high aperture ratio and is required to have rigidity, is made of metal. Aluminum is used as the metal and is anodized. A ground is provided to prevent static electricity. In many cases, the sound collecting unit cover that gives the sound collecting directivity is formed on a curved surface. The sound collection holes are distributed on the curved surface. A net as shown in FIG. 8 is attached to the inner surface of the sound collector cover 01.

A problem with such a sound collecting section cover is that the material cost, the press process cost, the post-processing cost, and the component cost are high, and the overall manufacturing cost is high. Furthermore, the curved metal body is unstable in shape and does not tightly bond to the device body. The metal sound collecting cover has another problem. To reduce the manufacturing cost, the casing body is made of resin by injection molding. Various sound waves such as reflected waves from the vibrating body built in the microphone and sound waves transmitted from the floor propagate to the casing body and the sound collecting cover. The casing body and the sound collecting cover vibrate by themselves, and also propagate acoustic wave energy of a specific wavelength and other vibration energy inside.

Since the resin of the casing main body and the metal of the sound collecting portion cover are different in hardness and different from each other, a new vibration is generated due to the interaction between the resin vibrating body and the sound collecting portion cover vibrating body, so-called chatter noise is generated. Let A chattering noise is also generated when a wave propagating in the resin vibrating body and a wave propagating in the sound collecting unit cover vibrating body overlap each other. Such chattering sound propagates in the casing body to the vibration detection body of the microphone. Although an electric circuit for cutting out such chattering noise is provided, it not only further increases the cost but also makes the sound quality unnatural.

It is known to provide a buffer between the casing body and the sound collecting cover. The cushioning member is necessary not only for preventing chatter noise but also for waterproofing. The capital investment for automating the process of fitting the packing manufactured in a separate process into the sound collecting part cover formed with a complicated curved surface increases the cost. It is known that a cushioning band is formed between the sound collecting cover and the casing body by applying an elastic material having adhesiveness to metal to the inner surface of the sound collecting cover to form a buffer band. .

The coating of such a cushioning material on a complicated curved surface has a non-uniform thickness. For this reason, the adhesion between the buffer band and the casing body is deteriorated, making it difficult to prevent chatter noise. Since elastic materials are also limited, suitable materials have not been used.

Further, the sound collecting section cover is attachable to and detachable from the casing body via the claw. Since the claw is integral with the sound collecting unit cover body and is made of metal, even if a good shock absorber is provided, the vibration energy propagates directly between the casing body and the sound collecting unit cover via the metal part. It is difficult to avoid chattering.

[0008]

SUMMARY OF THE INVENTION The present invention has been made based on such a technical background, and achieves the following objects.

It is an object of the present invention to provide a sound collector cover for an audio device and a method of manufacturing the same, which is inexpensive to manufacture.

Another object of the present invention is to provide a sound collecting section cover for an audio device that does not generate chatter and a method for manufacturing the same.

Still another object of the present invention is to provide a sound collecting section cover for an acoustic device which is low in manufacturing cost and does not generate chatter noise, and a manufacturing method thereof.

[0012]

Means for Solving the Problems To solve the above-mentioned problems, the following means are adopted.

The sound collecting cover of the audio equipment of the present invention 1 is a sound collecting cover which has a sound collecting microphone inside and is fitted into and mounted on a casing of the audio equipment body molded of the first resin. A sound collecting part cover body formed of resin and having a large number of sound collecting holes, and a packing that is integrally joined to the inner surface of the sound collecting part cover body and is formed of a third resin so that the outer surface side overlaps with the sound collecting part cover body. The audio device main body casing, the packing, and the sound collecting unit cover main body overlap each other in the thickness direction to form at least three layers, and the first resin forming an inner layer and the second resin forming an outer layer are , Is harder than the third resin forming the intermediate layer, and the material of the third resin is an elastic material.

A sound collecting portion cover of an audio equipment according to a second aspect of the present invention is characterized in that, in the first aspect, the first resin and the second resin are engineering plastics and are made of the same material.

A sound collecting portion cover of an audio equipment according to a third aspect of the present invention is the cover of the first or second aspect, wherein the first resin and the second resin are engineering plastics.
The resin is characterized by being an elastomer.

A sound collecting portion cover of an audio equipment according to a fourth aspect of the present invention is the cover for the sound collecting portion according to the first aspect, wherein the first resin and the second resin are engineering plastics and are made of the same material,
The third resin is an elastomer, and the third resin is fused to the second resin.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a sound collecting cover of an audio device, which comprises a sound collecting microphone which is fitted into a casing of a main body of the audio device and molded by the first resin. A method for manufacturing a sound collector cover of an audio device for achieving the same, comprising: a first step of molding a sound collector cover body having a large number of sound collecting holes with a second resin; and a sound collector molded in the first step. A second step of inserting the partial cover body into an injection mold, a third step of closing the injection mold to form a cavity between the injection mold and the inner surface of the sound collecting cover body, A fourth step of injecting a molten third resin into the cavity, wherein the first resin and the second resin are harder than the third resin, and the material of the third resin is elastic. It is a material.

In a fifth aspect of the present invention, there is provided a method for manufacturing a sound collecting cover for an audio device, wherein the third resin injected into the cavity melts the surface layer on the inner surface side of the sound collecting cover body by itself. It is characterized in that a fusion layer is formed in which the third resin and the second resin are melted by heat and enter each other.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a sound collecting part cover for an audio equipment, comprising the steps of:
The resin is characterized by being the same material.

In the sound collecting section cover of the audio equipment of the present invention, the packing is integrated with the sound collecting section cover by injection molding. Assembly is automated because it is injection molded. Since the internal natural frequency of the main body of the audio device and the internal natural frequency of the sound collector cover are the same or similar, no chattering sound is produced. External vibration of the main body of the audio equipment is attenuated by the sound collector cover and transmitted as it is. Therefore, no chatter sound is produced, or even if it is produced, it is attenuated.

[0021]

Next, an embodiment of the present invention will be described. FIG. 1 shows a first embodiment of a sound collector cover of an audio device of the present invention. A video camera is shown as the audio device. The casing body 1 has a curved surface portion 2 on the upper front side. A window is opened in the curved surface portion 2. The sound collecting section cover 3 covers the window. The sound collecting unit cover 3 is detachably fitted and attached to the casing body 1.

As shown in FIG. 2, the sound collector cover 3 is bent in a V shape. The material of the sound collector cover 3 is resin. Resin material is ABS resin, polycarbonate, P
It is possible to select from various engineering plastics such as P. The sound collecting unit cover 3 has an opening ratio of 60.
It has a large number of holes so as to be about%. This hole is the sound collection hole 4. In order to secure such an aperture ratio, the sound collecting unit cover 3 has a sufficient thickness.

The sound collecting section cover 3 has a peripheral edge portion 5 almost all around. The peripheral portion 5 rises integrally in the direction toward the casing body. The peripheral portion 5 strengthens the rigid structure of the sound collection cover 3 itself. The sound collecting unit cover 3 is formed of an upper portion 6 and a lower portion 7.
The upper part 6 and the lower part 7 are bent substantially orthogonally.

The sound collecting section cover 3 comprises a sound collecting section cover body 8 and a packing 9. Sound collector cover body 8
The packing 9 is joined to the inner surface of the upper portion 6 of the. The packing 9 forms an upper part of the sound collecting unit cover 3. The packing 9 is formed of a peripheral portion 11 and a central portion 12 which are closed in a substantially rectangular shape. The central portion 12 is a packing 9
The upper side and the lower side opposite to each other are connected.

A divided sound collecting window 13 is formed between both sides of the packing 9 and the central portion 12. An upper claw 14 that extends toward the casing body 1 projects from the peripheral edge portion 5 of the upper side of the upper portion 6 of the sound collection cover body 8. The upper claw 13 and the peripheral edge portion 5 are integrally formed.

From the lower end edge of the lower portion 7 of the sound collecting cover main body 8, a lower claw 15 protruding toward the casing main body 1 is projected. The lower claw 15 and the sound collecting unit cover body 8 are integrally formed. A central claw 16 that projects toward the casing body 1 projects from the central portion of the peripheral edge portion 5 of the sound collecting unit cover body 8. The central claw 16 and the sound collecting unit cover body 8 are integrally formed.

3 and 4 are cross-sectional views taken along a plane that includes a line III in FIG. 2 and is orthogonal to the sound collecting unit cover 3. As shown in FIG. 3, a thin net 17 is provided between the packing 9 and the sound collecting unit cover body 8. At the time of insert molding, which will be described later, the molten molding material forming the packing 9 penetrates into the mesh 17.

The mesh 17 is sandwiched between the packing 9 and the sound collecting cover main body 8 and integrated with the packing 9 and the sound collecting cover main body 8. FIG. 4 shows the sound collecting unit cover 3 with the net omitted. The net 17 is a dust collecting filter used so as not to interfere with sound collection.

As described above, the sound collecting unit cover of the audio equipment of the present invention is joined to the sound collecting unit cover body 8 by integral molding on the inner surface thereof and is molded with the third resin so that the outer surface side is the sound collecting unit cover body 8. A first casing which comprises an overlying packing, wherein the audio device body casing, the packing and the sound collecting unit cover body are overlapped in the thickness direction to form at least three layers, and to form an inner layer.
The resin and the second resin forming the outer layer are harder than the third resin forming the intermediate layer. FIG. 5 shows the first embodiment of the sound collecting cover of the audio equipment of the present invention for assembling the sound collecting cover 3 by the different material insert injection molding. The mold device 21 is a relatively movable three-body mold, and includes a first mold element 22, a second mold element 23, and a third mold element 2.
And 4. The second mold element 23 slides directly on the first mold element 22 and the third mold element 24 slides directly on the second mold element 23.

The second mold element 23 linearly reciprocates by an air cylinder (not shown). The third mold element 24 has a piston portion 25 in part. The piston part 25 is fitted in a cavity provided inside the second mold element 23. A part of the cavity is formed in the pneumatic chamber 26. Pneumatic chamber 26
Positive and negative pressure are alternately supplied to.

FIG. 5 is a front sectional view showing the mold closing state in which the second mold element 23 has advanced, positive pressure has been supplied to the pneumatic chamber 26, and the third mold element 24 has advanced. FIG. 6 shows the mold device 2
It is the oblique-axis projection view cut by the plane in the VI-VI line of FIG. The front surface 27 of the second mold element 23 and the front surface 28 of the third mold element 24 form a curved surface 29. Curved surface 29
Are cut at the central band 31.

The central band 31 has a concave cross section. The convex portion 32 where the second mold element 23 and the third mold element 24 form the front surfaces 27 and 28 is located inside the peripheral edge portion 5 of the sound collecting unit cover 3. Sound collecting unit cover body 8 including peripheral portion 5 and convex portion 32
A groove 33 having three sides (upper side and right and left sides) is formed between the two. Another groove 35 on one side is formed between the front portion 34 of the second mold element 23 and the convex portion 32.

Grooves 33, 34, and central band 31 formed by the second mold element 23, the third mold element 24, and the sound collector cover body 8.
Form a series of closed sun-shaped cavities 37. A gate 38 (FIG. 5) leading to the groove 35 is provided in the first mold element 22. The air pressure chamber 26 is set to a negative pressure so that the third mold element 24 is retracted and the second mold element 23 is retracted to open the mold device 21, and the sound collecting cover body 8 is moved to the first mold element 22.
To insert.

After advancing the second die element 23 to the most advanced position, positive pressure is introduced into the pneumatic chamber 26 to advance the third die element 24 to the most advanced position. The cavity 37 is formed by such a mold closing operation. The molten elastic material is injected and injected from the gate 38.

The elastic material is polyester elastomer,
Elastomers such as polyether elastomers and polyurethane elastomers can be used. If the material of the sound collector cover body 8 is ABS resin, polyether elastomer is used as the elastic material. If the material of the sound collector cover body 8 is PP, polyester elastomer is used as the elastic material.

By a combination of such materials or by subjecting the sound collecting cover body 8 to a primer treatment, the molten elastomer melts the surface layer of the material of the sound collecting cover body 8 by its own heat of fusion, Both materials enter into a sea-island shape and are nested (complex) to fuse. The way of entering is similar to Kaishima cotton.

It has been confirmed by electron microscope photography that the thickness of the fusion layer is about 3 microns. As described above, the sound collecting unit cover 3 includes the sound collecting unit cover body 8 and the packing 9.
Are assembled and fused together. Type 3 element 2
4 and then the second mold element 23 is retracted to the first
The sound collector cover 3 is removed from the mold element 22.

The sound collecting unit cover 3 assembled in this way is attached as shown in FIG. The vibration energy generated in the casing body 1 and propagated in itself reaches the surface of the packing 9. The natural frequency of the casing body 1 (the internal natural frequency, which is the vibration frequency of the combined vibration of the vibration between the molecular units and the vibration between the cluster units) and the natural frequency of the packing 9 are different. The vibration of the casing body 1 is not transmitted to the packing 9.

The entire vibration of the casing main body 1 is directly transmitted to the sound collecting cover main body 8 through the packing 9 which is fused to the sound collecting cover main body 8 and integrated with the sound collecting cover main body 8. Since the main body 1 and the sound collection cover main body 8 vibrate at the same frequency, chatter noise is not generated.

Although the sound collecting cover body 8 and the packing 9 are integrated, the vibration of the casing body 1 is damped by the packing 9. The packing 9 inherently vibrates in response to the vibration energy of the casing body 1, and the characteristic vibration energy is transmitted to the sound collecting unit cover body 8.

Since both the casing body 1 and the sound collecting cover body 8 are made of resin, the casing body 1 and the sound collecting cover body 8 have similar natural frequencies. Two vibrations whose frequencies are close to each other cause a beat but no chatter noise. Casing body 1 and sound collecting unit cover body 8
If they are the same material, the internal frequencies are the same, so that the chattering noise does not occur from the two internal vibrations.

Since the sound collecting unit cover body 8 and the packing 9 are in close contact with each other, the vibration energy of the casing body 1 is mainly transmitted through the packing 9, and the sound collecting unit cover body 8 is
The energy directly transmitted to the sound collecting part cover body 8 via the claws 14 and 15 of the above is small. The vibration energy of the casing body 1 is attenuated while being transmitted through the packing 9. The chatter is attenuated even if it occurs.

The sound collecting cover body 8 is injection-molded in advance. With sufficient thickness, the strength is guaranteed even when the aperture ratio is 60%. When the sound collecting cover main body 8 having the net 17 inserted on the inner surface is inserted into the first mold element 22 and the molding is performed, the net 17 is integrated with the sound collecting cover main body 8 and the packing 9. After the molding, the mesh 17 can be attached to the inner surface of the packing 9.

[0044]

According to the sound collector cover of the audio equipment and the method of manufacturing the same of the present invention, the work of assembling the unwieldy packing can be automated and the number of steps is reduced, so that the manufacturing cost is reduced and the chattering noise is not generated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a video camera to which a sound collecting unit cover of an audio device according to the present invention is applied.

FIG. 2 is an oblique-axis projection view showing the first embodiment of the sound collecting unit cover of the audio device of the present invention.

FIG. 3 is a front sectional view showing the first embodiment.

FIG. 4 is a front sectional view showing a modified form of the first embodiment.

FIG. 5 is a front cross-sectional view showing a molding apparatus used in Embodiment 1 of the method for manufacturing the sound collecting unit cover of the audio device of the present invention.

FIG. 6 is a perspective view showing a part of the mold device.

FIG. 7 is an oblique-axis projection view showing a known sound collector cover.

FIG. 8 is a perspective view showing a known net.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Casing main body 3 ... Sound collecting part cover 5 ... Peripheral part 8 ... Sound collecting part cover main body 9 ... Packing 22 ... 1st type | mold element 23 ... 2nd type | mold element 24 ... 3rd type | mold element

Claims (7)

[Claims] 1. A sound collecting cover which has a sound collecting microphone inside and is fitted into and mounted on an audio equipment main body casing molded of a first resin, and is formed of a second resin and has a large number of sound collecting holes. The sound collecting unit cover body and a packing that is integrally molded on the inner surface of the sound collecting unit cover body and is molded with a third resin so that the outer surface side overlaps with the sound collecting unit cover body. And the sound collecting unit cover main body are overlapped in the thickness direction to form at least three layers, and the first resin forming an inner layer and the second resin forming an outer layer.
The resin is harder than the third resin that forms the intermediate layer, and the material of the third resin is an elastic material sound collecting unit cover of an audio device. 2. The sound collecting unit cover for an audio device according to claim 1, wherein the first resin and the second resin are engineering plastics and are made of the same material. 3. The sound collecting section cover for audio equipment according to claim 1, wherein the first resin and the second resin are engineering plastics, and the third resin is an elastomer. 4. The engine according to claim 1, wherein the first resin and the second resin are engineering plastics and are made of the same material, the third resin is an elastomer, and the third resin is fused with the second resin. A sound collection cover for an audio device characterized by being worn. 5. A method for manufacturing a sound collecting part cover of an audio device for manufacturing a sound collecting part cover, which has a sound collecting microphone inside and is fitted into and mounted on an audio device main body casing molded of a first resin. Yes, a first step of molding a sound collecting section cover body having a large number of sound collecting holes with a second resin, and a second step of inserting the sound collecting section cover body molded in the first step into an injection mold. A third step of closing the injection mold to form a cavity between the injection mold and the inner surface of the sound collecting unit cover body, and a fourth step of injecting a molten third resin into the cavity The first resin and the second resin are harder than the third resin, and the material of the third resin is an elastic material. 6. The third resin according to claim 5, wherein the third resin injected into the cavity melts the surface layer on the inner surface side of the sound collecting unit cover body by its own heat of fusion to melt the third resin and the second resin. A method for manufacturing a sound collecting part cover of an audio device, wherein a fusion-bonding layer is formed so that the and the two enter into each other. 7. The method for manufacturing a sound collecting section cover of an audio device according to claim 5, wherein the first resin and the second resin are made of the same material.