JPS5929299A - Sound absorbing plate - 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] The present invention &J, 1! This is a sound plate, which is used as a sound absorbing plate that is effective underwater.

If the sweat absorption performance of the sound absorbing board is assumed to be total reflection from the wall surface equipped with the sound absorbing board, then the energy incident on the sound absorbing board and ++s
＋＊The relationship between the energy reflected from the surface of the board is 1, and the reflected energy is 11, and the absorbed energy is 1.

Conventionally, in addition to the one-layer type, there are two-layer types as shown in Figure 1.
There is a known multi-layered sound absorbing board in which the sound absorbing sides 1 and 2 with different acoustic characteristics are stacked together, but the boundary surface 3 between each layer is flat, and the sound is reflected inside the absorbing board. , absorption, and refraction-1 were relatively simple, and the sound absorption effect was also comparable. The sound absorbing board A is bonded to the wall surface B so as not to fall off.

On the other hand, the sound-absorbing plates installed in anechoic chambers on land have a Kuzapi-shaped surface, and when a sound wave reaches them, the Kl is reflected many times on the Coulivi surface of the surface and the sound is absorbed from each part. Although this is intended to enhance the sound absorption effect, it is inappropriate to equip the surface of an underwater vehicle with a sound absorption plate having such a structure because it increases underwater resistance.

In view of the above points, Kisaaki provides a sound absorbing board that can be used for underwater vehicles.In a multilayer sound absorbing board, the boundary between each layer is made with appropriate unevenness, and the sound absorbing board is made to reach the boundary. Reflects sound in multiple directions to increase sound absorption efficiency, and also
+ is widened to strengthen the bonding force between layers. .

In the present invention, in a sound-absorbing board made by combining and bonding multiple layers of acoustic/Ck red ff-absorbing materials, the boundary between C1 and Ck has an uneven shape, and the sound that reaches the boundary surface is absorbed in many directions. The gist of the invention is a suction board that has a structure that reflects light.
4'4's spindle, its thickness, number of layers, etc. i+: The layer is selected as appropriate, but the surface layer t4 is t', and the load such as water flow resistance is rt'
It is preferable to have a thickness of a certain degree and some rigidity, and a thickness of several tens of degrees and a layer number of 1d2 to 10 is desirable. The shape of the unevenness on the boundary surface of each sound absorption gain V, 1, V; - As mentioned above, various shapes such as pyramid shape are selected.JJ, unevenness 11
The height of 1 f-j as high as possible is effective for sound absorption in the low frequency range), but the upper limit of the height is determined by the thickness of the sound absorbing material and the number of layers7).

Figure 2 shows the structure of an example of the multilayer sound absorbing board C of the present invention.
- Overlapping and joining ≧, it is said that it is fitted to the wall B in the song, but the boundary 6V11 of the multilayer sound absorbing board C, the sound absorbing gain 4 side is pyramid 1 (the convex part 4' of the board is shaped like a goup) Place 2, sound absorption benefit 51111 on the four parts 5' and 1.
1. General sound absorbers +1~ and 8T in multilayer sound absorbing boards
', Next, the sound absorption mechanism and structure of the conventional type shown in Figure 1 and the sound absorption mechanism of the present invention shown in Figure 2 will be explained-! Ru.

Some of the sound is refracted and enters the interior at interfaces with different acoustic rupture properties, and some of the sound is reflected and enters the interior, and the remaining sound is reduced.
It reaches the wall surface while being reflected and is further attenuated as it is radiated from the surface. Generally, the absorption coefficient of a sound absorbing board is expressed by the following formula, which is expressed as the relationship between the sound incident on the sound absorbing board and the sound radiated from the surface.

α= (11-Ir)÷Ii Also, assuming total reflection at wall B, the energy absorbed inside the sound absorbing plate &J:11-1. ~ becomes. The amount of absorbed energy cannot be discussed because there are many factors involved, but if the sound absorbing board is thinner or thicker, the amount of energy absorbed is 1 greater. Published by λ, Ru. That is, the sound←l: 11% The energy e' absorbed by the culm, which has a long path to pass through the width of the tone plate, becomes large.

In FIG. 1 and FIG. 5, which shows a cross section of FIG. 2 and schematically shows all the absorption and reflection of the prize, a, 11, C, 6, t:
JJ"1 shows the path of 1-, (21+), (5b
).

(5d,) Subsequent reflections of the hill, ) 1 omitted - i'y
＋、ni!゛Sound Absorption Moon 1.2.4.5 Sound 71Tl 7
n row culm k,! , a part of it (f,) + (1b), (
! )1. ) 4- (2h), (4n,) 4- (4
b) + (4c), (5a) - (5b) + (5c)
+ (5cl) Totoru.

Sound absorbing material 1.4 K Tsuiteie +1 (1a) -1
-(+b) ((4FL) -1-(4b) -1-(
4c), more IJ! &, for t'F 472.5, (20) + (2b) < (5a) 4- (5b
) +(5c)! -(5+1) and potash sound absorption 4)q
(!) Comparison with sound absorption board 1. The line through which the sound passes
/J long, sound absorbing plate 1.1' (+157 1 energy v ("t Ir) rJ: person, sound absorbing plate no l
l11. The yield is also high/: I can say that.

Below, I mentioned the sound 71, which is composed of 2 different types of suction°, 4 types + pQ sounds - 4 types, 5 pieces j'-J, 10 movements 7τ4''♀ 7) ξ and of course f
It is iP.

Also, '311'6 F5 (1r7>, hW S'
r surface IF bar C&J2, pyramid 7F'''+
/S q) Convex 111] Part: l° Pa: The eyes of / are lined up neatly.
There are no particular restrictions on the shape, such as star-shaped or triangular grooves for easy production.
,do not have. In addition, the present invention is applied to all the layers of the multi-layer one-technique tone plate, and some layers V? :Can also be applied TT
It is J-Noh.

In order to avoid detection due to underwater sound wave oscillation,
It is effective as an underwater sound absorbing material for 11 days, but it is also effective for use as an anechoic material on land.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional multilayer sound absorbing plate, also showing the sound absorption and reflection mechanism, Fig. 2 is a perspective view of the sound absorbing plate of the present invention, and Fig. 6 kJ , In the cross-sectional view of the sound absorbing plate in Figure 2, the sound absorption and reflection mechanism is fJ (' (f- is shown as 2
It is. Iy agent Uchiguchi 1 Ming generation participation Hagiwara -

Claims (1)

[Claims] RWIF! In a sound-absorbing board made by combining and bonding j different sound-absorbing sides in multiple layers, the boundary surface of the sound-absorbing side has an uneven shape.
A sound-absorbing board characterized by the fact that it has an rlJl structure that reflects M- whose boundary reaches the surface in many directions.