JP2002215172A - Acoustic material an acoustic structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acoustic material which is arranged with a perforated plate having lightness in weight, high strength, high impact resistance and excellent sound absorption performance and an acoustic structure for the same. SOLUTION: A perforated material 2 of >=100 N.S/m3 in flow resistance of air per unit area having many fine pores communicating with the front and rear of, for example, the perforated material formed by compression bonding an assemblage of metallic fibers of aluminum, aluminum alloy, stainless steel, etc., by rolling, etc., a porous material formed by successively providing both surfaces or one surface of an assemblage of metallic fibers with net materials (not shown in Figure), such as expanded metals and compression bonding and molding the same are disposed on the back of the perforated plate 1 formed by subjecting metallic plates of, for example, aluminum, stainless steel, iron, etc., to the perforating of <=30% in opening rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-weight sound-absorbing material having excellent durability and strength for use in noise-reducing devices and vehicles that generate noise, or for use in soundproof walls, tunnels, trenches, and the like of roads and railways.

[0002]

2. Description of the Related Art Conventionally, as a sound absorbing material, there are a glass wool sound absorbing material obtained by processing glass fiber into a plate shape, and an inorganic porous sound absorbing material obtained by sintering ceramic particles or foaming a cement material. When used to perform sound absorption processing on the outside of a running vehicle, there has been a problem that the sound absorbing material is deteriorated and damaged by high-speed airflow, vibration, or the like, resulting in reduced performance or scattered fragments. Glass wool sound-absorbing material has a problem that its performance is apt to be reduced due to scattering of fibers due to high-speed airflow, and ceramic-based rigid sound-absorbing material is liable to crack, and furthermore, because of its heavy weight, its weight increases when mounted on a vehicle or the like. .

As a countermeasure against these problems, there is a method of protecting the surface of the porous sound-absorbing material with a perforated plate or the like. However, in order to prevent the sound absorbing performance from lowering, the aperture ratio of the perforated plate must be reduced to 30%.
% Or more, and when the aperture ratio is increased, there is a problem that the reinforcing effect is reduced. In addition, glass fibers and ceramics have a fear that fibers and fragments are scattered from the holes of the perforated plate.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and a light-weight, high-strength, shock-resistant, and sound-absorbing perforated plate is provided. An arranged sound absorbing material and a sound absorbing structure thereof are provided.

[0005]

SUMMARY OF THE INVENTION The above problem is caused by the fact that behind a perforated plate having an aperture ratio of 30% or less, there are a large number of pores communicating on the front and back, and the air flow resistance per unit area is 100%.
The problem can be solved by the sound absorbing material of the present invention, wherein a porous material of N · S / m ³ or more is provided. The present invention can be preferably embodied in a form in which the perforated plate is made of metal or resin, a form in which the porous material is made of metal, and a form in which they are combined.

[0006] Further, the above-mentioned problem is caused by the above (claim 1,
This problem can be solved by the sound absorbing structure of the present invention, wherein a sound insulating member is provided behind the sound absorbing material of 2 or 3) via a porous material and / or an air layer. This sound absorbing structure is suitably used for vehicles.

[0007]

Next, an embodiment of a sound absorbing material and a sound absorbing structure of the present invention will be described with reference to FIGS. The features of the sound absorbing material 3 of the present invention include:
A large number of pores communicating with the front and back are provided behind a perforated plate 1 having an opening ratio of 30% or less, for example, made of a metal plate of aluminum, stainless steel, iron, or the like. A porous material having a flow resistance of 100 N · S / m ³ or more, for example, a porous material obtained by pressing an aggregate of metal fibers such as aluminum, an aluminum alloy, and stainless steel by a method such as rolling molding, and an aggregate of metal fibers This is characterized in that a net material (not shown) such as expanded metal is attached to both surfaces or one surface, and a porous material formed by pressure bonding is provided.

Here, the perforated plate 1 which is a component of the present invention will be described. The perforated plate 1 is made of a metal plate made of aluminum, stainless steel, iron, or the like, and is provided with a hole 11 by punching, or a reinforced plastic such as plastic or FRP.
Use resin such as hard rubber. The thickness may be about 1-2 mm, but is not particularly limited.

The aperture ratio must be 30% or less, and more preferably 25% or less. In addition, the plane opening shape of the hole 11 is round, triangular, square, etc.
The cross-sectional shape of the hole 11 is a straight hole, a tapered hole,
What is necessary is just to select according to a use, such as burring. Hole 11
The size of the pore is not limited, but the pore diameter is preferably about 2 to 10 mm for the purpose of protecting the porous material.

Next, a description will be given of the porous material 2 which is a constituent member of the present invention disposed behind the perforated plate 1. The porous material 2 is a porous member having an infinite number of pores communicating with the front and back and having sound absorbing properties, and has a porosity of 20 to 50.
% Is preferable, and the air flow resistance per unit area is 10%.
Those having a value of 0 to 2000 N · S / m ³ are used. More preferably, it is 600 to 1500 N · S / m ³ . The plate thickness is suitably 5 mm or less.

The material of the porous material is preferably metallic or metallic. For example, a porous material 2 obtained by pressing an aggregate of metal fibers such as aluminum, an aluminum alloy, and stainless steel by a method such as rolling, and a net material (not shown) such as an expanded metal on both surfaces or one surface of the aggregate of metal fibers. , A porous material 2 formed by a method such as adding an adhesive or the like after pressing to harden, a porous material 2 obtained by sintering metal particles such as aluminum or an aluminum alloy, a metal A porous material 2 in which particles are hardened with an adhesive, or a porous material 2 in which a communication hole is provided by foaming a metal such as aluminum can be preferably used.

Among the above, in the case of the porous material 2 in which metal fibers are pressed, the thickness can be adjusted, for example, it can be reduced to about 1 mm, and the metal fibers are complicatedly entangled. Since peeling and scattering are unlikely to occur, it is particularly preferable as a material disposed inside or behind the perforated plate 1.

As the other porous material 2, the following materials may be used. Sintering of ceramic particles, foams, and foams of cementitious materials. A plate-shaped body made of ceramic fibers processed with an adhesive. Thermo-compressed body of plastic particles, plate-shaped body bonded with adhesive. Thermocompression bonding of plastic fiber, plate-like body bonded with adhesive.

As such a joint structure between the porous material 2 and the perforated plate 1, a non-adhesive structure in which the perforated plate 1 and the porous material 2 are simply overlapped with each other is also adopted. ,
It is preferable to form a surface-bonded structure or a surface-bonded structure by laminating by a method such as heating. Alternatively, the perforated plate 1 and the porous material 2 may be stacked and pressed by a method such as rolling or pressing. In this case, heat or an adhesive may be used in combination.

Further, the porous material 2 is brought into contact with the perforated plate 1 in the state of a raw material, and a process such as molding is performed to form the porous material 2 and the perforated plate 1 in an integrated state. You may. In order to improve the bondability between the perforated plate 1 and the porous material 2, a burring process (see FIG.
(See (3)) to form the bent burring portion 22, or a porous material may be inserted into the hole 11 of the perforated plate and formed (see FIG. 1 (2)) or may be formed as described above. Two methods may be used in combination. Further, the perforated plate may be arranged on one surface (front surface) of the porous material or on both surfaces (front surface, back surface).

Next, the combination of the perforated plate 1 and the porous material 2 will be described. Basically, the perforated plate 1 and the porous material 2 are in a one-to-one combination. However, as shown in the following example, one perforated plate and the other porous material may be combined and arranged. Perforated plate + porous material + perforated plate (see Fig. 1 (4)) Perforated plate + porous material A (low flow resistance) + porous material B
(Large flow resistance) (See FIG. 1 (5)) Perforated plate + Porous material C (made of metal) + Porous material D (made of glass fiber) (See FIG. 1 (5))

The sound absorbing properties of the sound absorbing material 3 thus obtained are as follows:
It can be adjusted by the sound absorption characteristics of the porous material 2.
The sound absorption characteristics of the porous material 2 are determined mainly by the air flow resistance (ventilation resistance) per unit area, the porosity, and the size and shape of the pores. Can be adjusted. For example, when the plate thickness is small, the size of the gap is reduced, and when the plate thickness is large, the size of the gap is increased, so that the air flow resistance per unit area is set to a predetermined value. By adjusting to
It can be adjusted to the required sound absorption characteristics. In order to increase the strength and the impact resistance, the thickness of the perforated plate 1 is adjusted to be large and the hole diameter is reduced.

Next, the sound absorbing structure of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The structure of this sound absorbing structure basically includes, as shown in FIG.
(For example, perforated plate 1 + porous material 2) + air layer 4 + sound insulating member 6, but between the sound absorbing material and the sound insulating member, a plurality of porous materials and air layers are provided. Can be arranged in combination. Sound absorbing material 3 + porous material 5 + air layer 4 + sound insulating member 6 (see FIG. 3 (2)) Sound absorbing material 3 + air layer 4 + porous material 5 + air layer 4 + sound insulating member 6 (see FIG. 3 (3))

As the sound insulating member 6, a metal such as iron or aluminum, a resin plate such as plastic, or an inorganic material such as concrete is suitable. As the porous material 5, the above-described materials can be appropriately used. The sound absorbing material of the present invention has a relatively thin porous material disposed behind a perforated plate, and further has a sound absorbing structure in which an air layer is disposed behind the perforated plate. There is a synergistic effect of the effect of converting sound waves by the porous material into heat energy and attenuating the sound energy, and high sound absorption characteristics can be obtained even if the aperture ratio of the perforated plate is small. The sound-absorbing structure thus obtained is preferably used as a sound-absorbing component such as a lower surface of a railway vehicle or around wheels. In this case, the vehicle body itself may be used as the sound insulating member.

[0020]

Next, the present invention will be described in more detail with reference to Table 1 showing examples of the present invention. A porous material (A) obtained by press-forming an aggregate of aluminum fibers having a fiber diameter of about 0.1 mm, and an aluminum material having an aperture ratio of 70 to 80% on both surfaces of an aggregate of aluminum fibers having a fiber diameter of about 0.1 mm. A porous material (B), which is formed by pressing and expanding an expanded metal, and an aluminum expanded metal having an opening ratio of 70% is disposed on one side of an aggregate of aluminum fibers having a fiber diameter of about 0.1 mm by pressure. Porous material (C),
(D) A stainless steel plate having a thickness of 1 mm was pasted on one side with a perforated plate having a circular hole, and the specimen No.
No. 1 to No. 11 sound absorbing materials were obtained. Specimens No. 12 under conditions outside the scope of the present invention, and Specimens Nos. 13 to 15 having a structure without a perforated plate were compared as comparative examples.

With respect to the sound absorbing materials of the above Examples and Comparative Examples,
The measurement of the normal incidence sound absorption coefficient and the impact test were performed. The normal incidence sound absorption coefficient was measured by providing an air layer behind the sound absorbing material or arranging a porous material, and a typical example of the sound absorbing characteristics is shown in FIG.
Table 1 shows the peak values. In addition, the impact test
A 50 cm square sound absorbing material for measurement was placed on sand, and a 0.5 kg steel ball was dropped from a height of 1 m to check whether or not the material was deformed.

According to this example, as shown in the test results in Table 1, it can be seen that the sound-absorbing material and the sound-absorbing structure of the present invention have a good sound-absorbing coefficient and excellent impact properties. You. As described above, the sound-absorbing material and the sound-absorbing structure of the present invention have a surface protected by a metal perforated plate having a relatively small opening ratio of 30% or less, and a porous material disposed behind the plate. It also uses a crimped aggregate of metal fibers, has a structure that does not easily break or scatter even at high speed airflow and impact, and has an appropriate sound absorption coefficient, so it is suitable as a sound absorbing material for vehicles etc. It becomes something.

[0023]

[Table 1]

[0024]

The sound-absorbing material and the sound-absorbing structure provided with the perforated plate according to the present invention are constructed as described above, so that the surface is reinforced by the perforated plate and the strength and impact resistance are excellent. Since it is thin and lightweight, it is easy to install, and even after installation, problems due to weight increase are unlikely to occur, and it has high sound absorption characteristics despite being reinforced with a perforated plate. And it can be used as a sound absorbing material especially effective for sound absorbing panels such as undersides and around wheels of vehicles running at high speed, for soundproofing panels used for noise barriers of road railways, and for tunnels and trenches of road railways. Has an effect. Therefore, the present invention has extremely high industrial value as a sound absorbing material and a sound absorbing structure in which a perforated plate that solves the conventional problems is arranged.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part for describing a sound absorbing material of the present invention.

FIG. 2 shows a combination (1 to 2) of components of the sound absorbing material of the present invention.
Sectional drawing which shows 5).

FIG. 3 is a schematic cross-sectional view showing combinations (1 to 3) of constituent members of the sound absorbing structure of the present invention.

FIG. 4 is a graph showing sound absorption characteristics of a typical example.

[Explanation of symbols]

1 perforated plate, 11 holes, 2 porous materials, 22 burring part, 3 sound absorbing materials, 4 air layers, 5 porous materials, 6 sound insulating members.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) E04B 1/86 E01F 8/00 F term (reference) 2D001 AA01 CA01 CB02 CD02 CD03 CD04 2D059 GG02 GG25 2E001 DF04 FA03 FA30 GA18 GA33 GA42 HA04 HA07 HA14 HB02 HB03 HB04 HD11 HD12 HE01 JA22 JA28 JB01 JB07 JB08 LA04 3D023 BA02 BB00 BD00 BE01 BE31 5D061 AA16 AA25 BB02 DD07

Claims (5)

[Claims] (1) Behind a perforated plate having an aperture ratio of 30% or less,
A sound-absorbing material comprising a porous material having a large number of pores communicating on both sides thereof and having a flow resistance of air per unit area of 100 N · S / m ³ or more. 2. The sound absorbing material according to claim 1, wherein the perforated plate is made of metal or resin. 3. The method according to claim 1, wherein the porous material is made of metal.
The sound-absorbing material described in 1. 4. A sound-absorbing structure, characterized in that a sound-insulating member is provided behind the sound-absorbing material according to claim 1, 2 or 3 via a porous material and / or an air layer. 5. A sound absorbing structure attached to a vehicle, wherein a sound insulating member is provided behind the sound absorbing material according to claim 1, 2 or 3 via a porous material and / or an air layer. Structure.