JPS63292195A - Sound absorber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a sound absorbing device used to absorb noise and music.

[Background technology]

Conventionally, as a sound absorbing device, as shown in FIGS. 1 and 2, an edge 2 is installed in the opening 4 of an enclosure (hollow envelope) 3 having an opening 4 on one side and forming an air chamber 5 inside. A configuration is provided in which the diaphragm 1 is arranged so as to be able to freely vibrate through the diaphragm 1. This sound absorbing device mainly absorbs sound in the low frequency range. Sound absorption characteristics of this sound absorption device (reverberation room method sound absorption coefficient)
An example of this is shown in (A> in Fig. 3). In Fig. 3, the vertical axis shows the sound absorption power, and the horizontal axis shows the frequency. In order to also absorb high-frequency sound with this sound absorbing device, the applicant: The application has been filed for a device in which a porous sound absorbing material 10 such as glass wool is installed in the front of the enclosure 3. This composite sound absorbing device is shown in FIG.
Also, the sound absorption characteristics of this composite sound absorption device (reverberation room method sound absorption coefficient)
This composite sound absorbing device, an example of which is shown in FIG. 5, has the advantage of having both a low frequency sound absorbing ability due to the resonance phenomenon of the diaphragm 1 and a high frequency sound absorbing ability due to the porous sound absorbing material 10. However, on the other hand, by installing the porous sound absorbing material 10 on the diaphragm 1, there is a drawback that the thickness is thicker than that of the sound absorbing device for sound absorption as shown in FIG.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to provide a sound absorbing device that has the same thickness as a low-frequency sound absorbing device and is capable of absorbing sound up to a high frequency range.

[Disclosure of the invention]

The gist of the present invention is to provide an enclosure having an opening on one side and forming an air chamber inside, a diaphragm disposed to close the opening surface of the enclosure, and a diaphragm between the opening edge of the enclosure and the diaphragm. In a sound absorbing device, the diaphragm is made of a honeycomb core material filled with a porous material and an edge that supports the diaphragm with respect to the enclosure so that it can vibrate freely. This is a sound absorbing device characterized by being composed of a film-like material stretched over the room-side surface and a mesh-like material stretched over the opposite surface. The following description will be made based on the actual drawings.

In the sound absorbing device as shown in FIG. 1, the diaphragm 1 must be made of a light and highly rigid material so that the diaphragm 1 can resonate in a single manner with a large amplitude. Therefore, conventionally, the diaphragm l of the honeycomb sandwich structure shown in FIG. 6 has been used as the diaphragm in the embodiment shown in FIG. This is a honeycomb core 7 made of aluminum, paper, etc.
It consists of a thin foil 6 made of aluminum or the like adhered to both sides of the honeycomb core 7.

However, as shown in FIGS. 7 and 8, the diaphragm l of the present invention uses a mesh material 8 instead of the thin film 6 on the opposite side of the enclosure internal air chamber in the honeycomb sandwich structure, and further includes a honeycomb core. 7 is filled with a porous sound absorbing material 9 such as a porous synthetic resin foam or glass wool.

The diaphragm 1 is stretched over an opening 4 of an enclosure 3 via an edge 3.

According to this configuration, sound waves in the low frequency range enter the inside of the diaphragm 1 through the gaps in the mesh-like material 8, transmit through the porous material 9, and are stopped by the thin film 6. The diaphragm l is caused to resonate by the same frequency component as the resonant frequency of the sound absorbing device in the incoming sound wave, and as a result, it absorbs sounds around that frequency.

On the other hand, high-frequency sound waves enter the inside of the diaphragm 1 through gaps in the mesh-like material 8 and are absorbed by the porous material 9.

Here, if the total mass of the mesh-like material 8 and the porous material 9 is the same as one sheet of the thin film 6 shown in FIG. There is no difference.An example of the sound absorption characteristics (reverberant room sound absorption coefficient) in this case is shown in (B) in Figure 3.The sound absorption characteristics when both sides are thin films ((A) in Figure 3) It can be seen that the sound absorption characteristics in the high frequency range are better than those shown in Figure 1).

The material of the mesh-like material 8 is not limited, and its structure may be a combination of wire rods as shown in FIG. 7, or a perforated membrane as shown in FIG. I do not care.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to improve the sound absorption ability in the high frequency range without reducing the sound absorption capability in the low frequency range of the conventional sound absorbing device or increasing the thickness. effective.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a sound absorbing device according to a conventional example, FIG. 2 is a sectional view of the same as above, FIG. 3 is a graph showing sound absorption characteristics of sound absorbing devices according to a conventional example and an embodiment of the present invention, and FIG. 4 is a cross-sectional view of a sound absorbing device according to another conventional example, FIG. 5 is a graph showing the sound absorption characteristics of the same sound absorbing device as above, and FIG. 6 is a partial cutout of the diaphragm of the sound absorbing device according to the conventional example of FIG. 7 is a perspective view of a sound absorbing device according to an embodiment of the present invention, FIG. 8 is a sectional view showing the same diaphragm as above, and FIG. 9 is a mesh-like diaphragm of another embodiment of the present invention. It is a perspective view showing a material. DESCRIPTION OF SYMBOLS 1... Vibration plate, 2... Edge, 3... Enclosure, 4... Opening, 6... Surface material of diaphragm, 7
...Honeycomb core, 8...Mesh-like material of diaphragm, 9...Porous sound-absorbing material. Figure 1 Figure 12 Figure 3 Figure 14 Figure 5B! 1 Circumferential liquid number (H2) 8m I9Ill

Claims (1)

[Claims] (1) An enclosure that has an opening on one side and forms an air chamber inside, a diaphragm arranged to close the opening of the enclosure, and a space between the opening edge of the enclosure and the periphery of the diaphragm. In a sound absorbing device, the diaphragm is arranged on a honeycomb core material filled with a porous material and is stretched on the air chamber side surface of the honeycomb core material. A sound absorbing device characterized by comprising a film-like material provided on the membrane and a mesh-like material stretched on the opposite surface.