JPH0887279A - Sound absorbing body - Google Patents

Abstract

PURPOSE: To provide a sound absorbing body having improved corrosion resistance, workability and mass-productivity, which is made light in weight, whose porosity is easily made uniform, having no dispersion in the sound absorbing function and also having a very large sound absorbing width. CONSTITUTION: The body is constituted of a back board 4, a back side sound absorptive laminated body 3 mounted on the surface of the back board 4 and provided with plural back tubular sound absorbing chambers 3a opening to the opposite side of the back board 4, a porous intermediate sound absorbing sheet 2 laminated on the open surface of the back tubular sound absorbing chambers 3a, an upper sound absorptive laminated body 31 laminated on the porous intermediate sound absorbing sheet 2 and provided with plural upper tubular sound absorbing chambers 31a opening to the front and back sides and a front porous sound absorbing sheet 21 laminated on the front opening surface of the upper sound absorptive laminated body 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorber having a porous structure, and more particularly to a sound absorber for versatile use which is excellent in sound absorbing efficiency, size of sound absorbing width, heat insulating property and vibration damping property and is lightweight. It is a thing.

[0002]

2. Description of the Related Art As a conventional sound absorbing body, Japanese Patent Laid-Open No. 63-1
As described in Japanese Patent No. 16197, a back plate,
There is a porous structure formed by laminating a sound absorbing laminate having a plurality of tubular sound absorbing chambers on the surface of the back plate, and further laminating a porous metal plate on the surface of the sound absorbing laminate. This porous metal plate is composed of a laminated body of aluminum-based X-band metal and a metal fiber layer, and the noise that has passed through the porous metal plate into the sound absorbing laminate is tubular in the sound absorbing laminate. In the sound absorbing room, it is effectively converted into heat and attenuated and absorbed.

In the conventional sound absorber design method, the noise frequency emitted by a noise source is measured, the main frequency of the noise is sought, and the sound absorption design is performed by preferentially absorbing the sound in the vicinity of this frequency. Was trying to suppress. Such a method is an effective means for reducing the noise around the peak value of the noise, but the sound absorbing design is complicated, and the sound absorbing body is not an individual mass production target. In addition to the problem that the noise is applied, there is a problem that the noise reduction effect is low for the noise in the area outside the noise reduction target, and the noise reduction as a whole is limited.

In addition, although the sound absorbing body using this porous metal plate has a very excellent sound absorbing performance in the main frequency range of noise, it cannot be used in a corrosive environment because the constituent members are made of metal. Therefore, it is heavy, unsuitable as an interior material for high-tech equipment for the purpose of weight reduction, difficult to cut, and cannot be easily molded into an arbitrary shape. Since the porous metal plate is a laminated body of an ex-band metal and a metal fiber layer, there are difficulties in mass production, and in the case of a high cost porous metal material,
Porosity is likely to be non-uniform, sound absorption performance varies, and since the outermost layer is a metal laminate, there is no water repellency,
There is a problem that sound absorption performance is impaired when water enters.

[0005]

The problem to be solved by the present invention is that it has excellent corrosion resistance, workability, mass productivity, is light in weight, and has a uniform porosity, and has a uniform sound absorption performance and a very wide sound absorption width. To provide the body.

[0006]

A sound absorber according to claim 1.
(1) is a "rear plate (4) and a plurality of rear side tubular sound absorbing chambers (3a) attached to the surface of the rear plate (4) and opened on the opposite side of the rear plate (4). A back side sound absorbing laminate having (3), a porous intermediate sound absorbing sheet (2) laminated on the opening surface where the back side tubular sound absorbing chamber (3a) is opened, and the porous intermediate sound absorbing sheet.
(2) is laminated on top, the upper sound absorbing laminate (31) having a plurality of upper tubular sound absorbing chambers (31a) opened on the front and back, and laminated on the front side opening surface of the upper sound absorbing laminate (31) It is composed of a porous surface-side sound absorbing sheet (21) ”.

The noise that has entered the upper tubular sound absorbing chamber (31a) through the porous surface-side sound absorbing sheet (21) is
The frequency component of the target region of (31a) is effectively absorbed by the attenuation effect. Then, the frequency component outside the target region of the upper tubular sound absorbing chamber (31a) that has not been absorbed is
Back side sound absorbing laminate passing through the porous intermediate sound absorbing sheet (2)
(3) The frequency components in the target area of the back side tubular sound absorbing chamber (3a) are effectively absorbed by the damping effect. Furthermore, generally speaking, the upper tubular sound absorbing chamber (31a)
And the sound absorption chamber (3a + 31) equivalent to the sum of the back side tubular sound absorption chamber (3a)
The frequency component adapted to a) is also absorbed, and as a result, in the present invention, the sound absorber (1) can have a very wide sound absorption width.

Further, the surface side sound absorbing sheet (21) facing the noise source is softer than metal, has fine irregularities on the surface, and is made of fibrous or sponge-like material or resin particles having an appropriate porosity. Since it is composed of, no reflected sound is produced. Thereby, the noise can be reduced extremely effectively.

If the porosity of the porous sound absorbing sheet (2) (21) is too small, it will be difficult to introduce noise into the tubular sound absorbing chambers (3a) (31a), and if it is too large, the noise once entered will leak. Therefore, it is preferable to set 40 to 60% (optimally around 45%).

According to a second aspect of the present invention, "an upper sound-absorbing laminate (31) having a plurality of tubular sound-absorbing chambers (31a) opened on the front and back sides, and a porous layer laminated on the opening surface of the upper sound-absorbing laminate (31). The sound absorbing sheets (21) are alternately laminated over a plurality of layers.'The sound absorbing width increases as the number of stacked upper sound absorbing laminates (31) and porous sound absorbing sheets (21) increases. Wider, no need for special design for specific noise sources (5),
One type of sound absorber (1) can be used, and as a result, the sound absorber (1) can be mass-produced.

According to claim 3, the height of the sound absorbing laminate (3) (31) ...
(H1) (H2) ... is different for each sound absorbing laminate (3) (31) ”
As a result, the sound absorption frequency of each layer is different, and the width of the sound absorption frequency region can be expanded from the low frequency region to the high frequency region.

[0012] Claim 4 is characterized in that "the porosity of the sound absorbing sheet (2) (21) ... becomes larger as it is closer to the back plate (4) side", whereby the noise gets closer to the back side. It gradually becomes easier to pass through the sound absorbing sheet (21) and does not reflect and leak to the outer surface side.

According to claim 5, "the surface of the sound absorbing sheet (21) is uneven.
(2a) is formed '', whereby the noise (10) coming from the noise source (5) can be effectively taken into the sound absorbing sheet (21), and the back tubular It is possible to more easily introduce noise into the sound absorbing chamber (31a).

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a perspective view showing a first embodiment of the sound absorbing body (1) of the present invention. The sound absorbing body (1) of the first embodiment is composed of two layers of sound absorbing sheets (2) and (21), two layers of sound absorbing laminates (3) and (31), and a back plate (4).

Materials for the sound absorbing sheet (2) include, for example, a fibrous material, a sponge material, and a material in which resin particles are hardened. Here, the fibrous material will be mainly described. As the fibrous material, there are a woven fabric laminated and a non-woven fabric processed as described later. Here, an example of processing a non-woven fabric will be mainly described.

The fiber materials include, for example, natural fibers and synthetic fibers. As the synthetic fibers, for example, a resin having a high melting point component is used as a core material (2a), and a resin having a low melting point component is used as a sheath material (2b) around the core material. ), The heat fusion-bonded composite fiber (2A) and long / short fibers used by spraying or applying a binder. Examples of the heat fusion composite fiber (2A) used in the sound absorbing sheet (2) include various composite polyolefin fibers, polyethylene terephthalate, and polyacetal (for example, low melting point heat adhesive composite fiber {sheath material (2b) is low). Melting point polyethylene is used, and polypropylene is used as the core material (2a)}, high-bulk and high-heat-adhesive composite fiber {of the eccentric sheath-core type in which the core material (2a) is polypropylene and the sheath material (2b) is polyethylene. Cross-sectional structure}, highly adhesive composite fiber {core material
(2a) polypropylene, sheath (2b) special polyethylene with sheath-core type cross-sectional structure}, PE / PET composite fiber (core (2a) polypropylene, sheath (2b) special polypropylene (Having a sheath-core type cross-sectional structure with a melting temperature of mp = 140 ° C.)} ”and the like.

Other fibers used in the sound absorbing sheet (2) include nylon, polyester, acrylic, rayon, tencel, chitin, collagen, acetate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyurethane, polyalkyl. Examples thereof include paraoxybenzoate-based, amorphous, fluorine-based fibers, and crow fibers, or a composite thereof in which these are appropriately mixed according to the intended use. These are used with binders.

Sound absorbing sheet using heat fusion composite fiber (2A)
(2) As a manufacturing method of (21) ..., (I) When the heat fusion composite fiber (2A) is a short fiber,
Short fibers are overlaid, and (b) Next, the short fibers are overlaid with a needle punch to form a uniform nonwoven sheet, and (c) subsequently, the punching material is heated while being compressed. When heat treatment is performed while compressing the heat fusion composite fiber (2A),
The sheath material (2b) of the fiber (2A) is melted and fused to each other at the contact portion of the fiber (2A). (D) When the compression / heating step is completed, the sheet material having a predetermined porosity is cooled by cooling while being compressed. Here, since the core material (2a) has a higher melting point than the sheath material (2b), this composite fiber (2A) retains the fiber morphology even after heat treatment, and must maintain the molded shape during heat compression processing. Can be done. Sound absorption sheet (2) (21) by the heat compression processing
The porosity of ... is set to 40 to 60% as described above, but since the low density non-woven fabric is heated and compressed, the porosity is the whole of the sound absorbing sheet (2) (21). Becomes uniform at. As will be described later, when used, a material having an appropriate porosity is selected and used in accordance with the laminated portion.

(II) In the case of short fibers used with a binder, (a) short fibers are stacked, and (b) next, short fibers are stacked and punched with a needle punch to form a uniform nonwoven fabric. As a sheet, (c) Subsequently, a binder is sprayed or applied to the punching processed material so that the fibers are easily bonded at their contact parts, and (d) finally compressed and stored to have a predetermined porosity. Use as sheet material

(III) In the case of producing the sound absorbing sheet (2) (21) ... From the nonwoven fabric of the heat fusion composite fiber (2A), (a) heating a cotton-like nonwoven material having a high porosity, B) Subsequently, cooling is performed in a compressed state to obtain a sheet material having a predetermined porosity.

(IV) In the case where the fibers are ordinary long fibers, (a)
Weaving the long fibers, (b) Next, spraying or applying a binder to make it easy for the fibers to adhere to each other at their contact portions, and (c) subsequently, folding and stacking the binder-coated long fibers, ( D) Finally, compress and store to obtain a sheet material having a predetermined porosity.

Other materials for the sound absorbing sheet (2) include sponge-like materials and resin particles.
The sponge applied to the present invention is preferably of the open-cell type. As the material, for example, urethane foam molded products, foamed styrene foams, and polyethylene foam molded products are generally used. As the resin particles, for example, raw material particles for injection molding having a diameter of about 0.1 to 1 mm are used, which are filled in a mold and heated to fuse the contact portions. To form. As the material, for example, acrylic, polyethylene, polypropylene or the like is used.

The sound absorbing laminates (3) (31) ... Are also common to all the embodiments of the present invention, but the tubular sound absorbing chambers (3a) (31a) ...
Although it may be configured in any shape as long as it is provided with, it is generally sufficient to use what is known as a so-called honeycomb structure, and this structure has mechanical strength as well known. Extremely large. Therefore, the mechanical strength can be sufficiently exerted even if the wall thickness is made thin, and the structure is optimal for reducing the weight of the sound absorbing body (1).

The tubular sound absorbing chambers (3a) (31a) ... can have various polygonal shapes in addition to circles, ellipses and triangles. The material of the sound absorbing laminate (3) (31) ... is not particularly limited, but other than kraft paper impregnated with epoxy resin (paper honeycomb material), vinyl chloride material,
A thin aluminum material is used. The cell size and wall thickness are not particularly limited either, but here, cell size 1
Those having a thickness of 0 to 15 mm and a wall thickness of 0.1 mm are used. The heights (H1) (H2) of the sound absorbing laminates (3) (31) ... Are determined depending on the frequency of the sound to be absorbed. The higher the height, the easier it is to absorb low frequency sounds.

Further, the material of the back plate (4) is not particularly limited, but it is important that the back plate (4) is impermeable to air, and a synthetic resin plate, a cardboard, a rubber plate, a wooden plate, an aluminum plate, etc., which has no air permeability can be processed. Is preferred. Further, when a soft material is used as the back plate (4), the sound absorbing sheet (2) is highly flexible, so that it can be easily attached to a complicated curved surface. The back plate
(4) is a separate body and is integrated with an adhesive because the sound absorbing laminates (3), (31), ... Are made up of paper / honeycomb with openings on the front and back in this embodiment. However, of course, the present invention is not limited to such a case, the tubular sound absorbing chamber (3a) of the back side sound absorbing laminate (3) may have a bottomed tubular shape, and in this case, the bottom of the tubular sound absorbing chamber (3a) is naturally a back plate. It becomes (4). Top Sound Absorption Laminate (31)
Is used with openings on the front and back.

Sound absorbing sheets (2) (21) ..., Sound absorbing laminates (3) (31)
The method for integrating the back plate (4) and the back plate (4) may have any configuration, but in this embodiment, a vinyl acetate adhesive or an instant adhesive (α-cyanoacrylate adhesive), a hot melt adhesive Is used. Although the bonding method is not specified, it is necessary to bond the sound absorbing sheet (2) side so that the sound absorbing sheet (2) is not clogged as much as possible in order not to impair the porosity. In (), in order to prevent sound leakage, it is necessary to prevent a gap from being formed between the sound absorbing laminate (3). The clogging on the sound absorbing sheet (2) (21) ... side is preferably 3% or less of the surface area of the entire sound absorbing sheet (2). It is also possible to use an adhesive sheet instead of the adhesive as long as the porosity is not impaired.

The sound absorbing body (1) is made of the above material. In the first embodiment, as shown in FIGS. 1 to 3, the back side laminate (3) is placed on the back plate (4). , The intermediate sound-absorbing sheet (2) is bonded onto it, and the upper laminate (3
1) is adhered, and the surface side sound absorbing sheet (21) is adhered as the uppermost layer. The heights (H1) and (H2) of the laminates (3) and (31) may be the same, but the heights (H1) and (H2) may be different for the reason described below when it is desired to have a wide sound absorption frequency range. You can do this. Also, the intermediate sound absorbing sheet (2) and the front side sound absorbing sheet (21)
Although the same porosity may be used, the sound in the frequency range that is not significantly attenuated in the upper laminate (31) is
It is desirable that the porosity of the intermediate sound-absorbing sheet (2) be larger than that of the surface-side sound-absorbing sheet (21) so that the intermediate sound-absorbing sheet (2) can easily enter the inside.

Next, the operation of the sound absorbing body (1) according to the present invention will be described. FIG. 5 shows an example in which the sound absorbing body (1) of the present invention is erected and surrounded around a mechanical device which is a noise source (5). According to this, the noise (10) generated from the mechanical device (5) diffuses to the surroundings, but it is effectively absorbed by the mechanism as described below.

That is, FIGS. 6 and 7 are explanatory views schematically showing the sound absorbing mechanism of the sound absorbing body (1), which is the tubular sound absorbing chamber (3a).
(31a) is a series container with volume (V1) (V2) and height (H1) (H2)
(6) Corresponds to (61), the pores of the sound absorbing sheet (2) (21) have a diameter (d1
φ) (d2φ) and lengths (t1) (t2) correspond to the mouths (7) (71). Also, the volume entering the mouth (7) (71) corresponds to the weight (8) (81) of weight (m1) (m2), and the containers (6) (61) correspond to the series springs (9) (91). , Can be handled as such a vibration system.

As is clear from such a mechanism, the tubular sound absorbing chamber (31) is opened from the mouth portion (71) corresponding to the pores of the sound absorbing sheet (21).
When noise (10) having high and low mixed frequencies enters the inside of a), the vibration system attenuates it and the sound is effectively absorbed by the container (61) corresponding to the spring (91). Here, the frequency component of the noise (10) that is mainly absorbed is adapted to the height (H2) of the tubular sound absorbing chamber (31a), and the sound absorption effect of the frequency component that is not adapted is not high. Therefore, as shown in FIG. 10, here, the sound near the frequency matching the height (H2) of the tubular sound absorbing chamber (31a) is greatly attenuated, and its peak value is reduced.

Frequency components that do not fit into the upper tubular sound absorbing chamber (31a) pass through the intermediate sound absorbing sheet (2) and the back side sound absorbing laminate (3).
It penetrates inside and is absorbed by the sound absorption theory. When the heights of the upper sound absorbing laminate (21) and the rear sound absorbing laminate (2) are different, the frequency components not attenuated in the upper sound absorbing laminate (21) are attenuated in the rear sound absorbing laminate (2). To be done.

Further, since the upper sound absorbing laminate (21) and the rear sound absorbing laminate (2) are connected in series, the height (H2) of the upper sound absorbing laminate (21) and the rear sound absorbing laminate are It will also act as a laminate equal to the sum of the height (H1) of (2), the height (H2) of the upper sound absorbing laminate (21) and the height (H) of the back side sound absorbing laminate (2).
When 1) is equal, the noise component near the frequency range that matches the height (H1 = H2) and the noise component near the frequency range that matches the height of the sum (H1 x 2) are mainly attenuated. If the height (H2) of the upper sound absorbing laminate (21) and the height (H1) of the back side sound absorbing laminate (2) are different, the upper sound absorbing laminate (21)
Noise component near the frequency range that conforms to the height (H2) of the back surface, and the noise component near the frequency range that conforms to the height (H1) of the back side sound absorbing laminate (2), and the sum (H1) + (H2 The noise components in the vicinity of the frequency range that match the height of) are mainly attenuated. This achieves sound absorption in a wide frequency range.

When the heights (H1) and (H2) of the laminates (2) and (21) are equal, noise components in the vicinity of the frequency range matching the height will be doubly absorbed. It is effective for absorbing sound when the decibel value of the noise component is excessive.

In this way, the sound once taken inside the laminate (2) (21) is attenuated and effectively absorbed, and there is no chance of secondary leakage to the outside. , Noise source
The sound from (5) does not reflect even if it collides with the surface of the surface side sound absorbing sheet (21) which is a soft non-woven compressed body, and it is possible to achieve a very effective sound absorbing as a whole. still,
As the number of laminated sound absorbing laminates having different heights is increased, sound is more widely and finely absorbed from the high frequency region to the low frequency region.

Further, the sound absorbing sheet (2) of the sound absorbing body (1) according to the present invention is prepared by mixing flame-retardant fibers (rock wool, glass wool, etc.) or flame-retarded fibers (flame retardant into the fibers). It can also be formed by using a fiber surface coated with a flame retardant), which allows it to be used as a flame-retardant sound-absorbing building material, or by impregnating with an antibacterial agent, such as a hospital. It can also be used for sound absorbing partitions. Furthermore, when impregnated with a fungicide, it can also be used as a sound-absorbing building material in places with high humidity such as pools, and the sound-absorbing sheet (2) of the sound-absorbing body (1) should be impregnated with an appropriate chemical. Therefore, it can be used as a sound absorbing material that is suitable for various purposes. Further, as a simple fireproof specification, the flame-retardant fiber layer may be laminated on the front surface side sound absorbing sheet (21).

Further, as shown in FIG. 8, it is possible to install the sound absorbing body (1) with the sound absorbing surfaces facing the front and back, and in this case, it is possible to effectively absorb the sound inside and outside. . Since the sound absorbing body (1) of the present invention has the sound absorbing sheet (21) (particularly preferably thick one) as its surface material, it functions as a heat insulating material and does not resonate even when vibration is transmitted. It also functions as a damping material.

FIG. 9 shows an uneven surface (2) on the outer surface of the sound absorbing sheet (2).
In the example in which b) is formed in one direction, the angle of the unevenness (2 b) is 15 ° ~
About 45 ° (preferably 30 °) is adopted. Unevenness (2
The formation direction of b) may be one direction, but may be intersected at a right angle or at an angle, or may be formed vertically and horizontally in a herringbone pattern. This makes it easier to introduce the noise (10) into the sound absorbing sheet (2).

FIG. 10 is a graph in the case of measuring the sound absorption coefficient of noise by the sound absorbing body (1) of the present invention. The vertical axis represents the reverberation room sound absorption coefficient and the horizontal axis represents the center frequency of noise. The thickness of the fibrous sound absorbing sheet (21) on the front surface side is 3 mm, the porosity is 45%, the height (H2) of the tubular sound absorbing chamber (31a) on the front surface side is 20 mm, and the cell size is 12 mm, the wall thickness is Is 0.1 mm.
Moreover, the thickness of the intermediate fibrous sound absorbing sheet (2) is 3 mm, the porosity thereof is 60%, and the tubular sound absorbing chamber (3
The height (H1) of a) is 30mm and its cell size is 12mm,
The wall thickness is 0.1 mm. According to this, it can be seen that a very remarkable sound absorbing effect is exerted in the frequency region of 250 Hz or higher, and a certain sound absorbing effect is exerted even in the frequency range of 250 Hz or lower. In addition, the sound absorbing layer is
By layering, the sound absorbing effect of 20 mm, the sound absorbing effect of 30 mm, and the sound absorbing effect of 50 mm obtained by adding the sound absorbing effect are synergistically obtained, and the noise in the frequency region is absorbed in a wide range. .

The number of layers of the sound absorbing body (1) is not limited to two layers as a matter of course, and it is also possible to have three or more layers, and the sound absorbing body (1) having an appropriate number of layers is designed according to the noise situation at the site. Will be The height of the laminate and the porosity of the sound absorbing sheet will be appropriately selected based on the above theory.

FIG. 9 shows an uneven surface (2) on the outer surface of the sound absorbing sheet (2).
In the example in which b) is formed in one direction, the angle of the unevenness (2 b) is 15 ° ~
About 45 ° (preferably 30 °) is adopted. Unevenness (2
The formation direction of b) may be one direction, but may be intersected at a right angle or at an angle, or may be formed vertically and horizontally in a herringbone pattern. This makes it easier to introduce the noise (10) into the sound absorbing sheet (2).

The sound absorbing sheet (21) used in the present invention
(2) If the constituent material of the "particularly the sound absorbing sheet (21) on the front surface side" has water repellency or is coated with a water repellent, the sound absorbing sheet (21) (2) as well as the tubular sound absorbing chamber Since water does not enter the inside of the (3a) and (31a), the porosity is not impaired, the inner volume of the tubular sound absorbing chambers (3a) and (31a) is not impaired, and the sound absorbing property is not impaired.

[0042]

In the sound absorbing body of the present invention, since the sound absorbing laminated body and the sound absorbing sheet are alternately laminated in plural layers, the frequency component of the target region of each tubular sound absorbing chamber is effectively absorbed by the damping effect. Therefore, the frequency components outside the target area that have not been absorbed will pass through the sound absorbing sheet and enter the next sound absorbing laminated body to be absorbed, resulting in a very wide sound absorbing effect. I was able to do something. Furthermore, the surface side sound absorbing sheet facing the noise source is softer than metal and has fine irregularities on the surface, and is composed of a porous material such as a fibrous or sponge-like material having an appropriate porosity and a resin particle hardened. Therefore, no reflected sound is produced. or,
When the height of the sound absorbing laminate is different for each sound absorbing laminate, the sound absorbing frequency of each layer is different, and the width of the sound absorbing frequency region is expanded from the low frequency region to the high frequency region. You can Further, when the porosity of the sound absorbing sheet increases toward the rear plate side, the noise gradually passes through the sound absorbing sheet toward the rear side and is not reflected and leaked to the outer surface side. When unevenness is formed on the surface of the sound absorbing sheet, noise can be effectively taken into the sound absorbing sheet, and the noise can be more easily introduced into the tubular sound absorbing chamber behind.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a sound absorbing body according to the present invention.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is a front view of an embodiment of the sound absorbing body according to the present invention.

FIG. 4 is an enlarged cross-sectional view of fibers used in the sound absorbing sheet of the present invention.

FIG. 5 is a front view when the sound absorbing body of the present invention is arranged around a mechanical device.

FIG. 6 is a principle diagram for explaining a sound absorbing mechanism in the present invention.

7 is a principle diagram when the mechanism of FIG. 6 is rewritten into a mechanical expression.

FIG. 8 is a perspective view of another usage example of the sound absorbing body according to the present invention.

FIG. 9 is a perspective view of the sound absorbing sheet according to the present invention in which irregularities are formed on the outer surface.

FIG. 10 is a graph when the sound absorption coefficient of each frequency of the sound absorbing body of the present invention is measured.

[Explanation of symbols]

 (1) ... Sound absorbing body (2) ... Porous sound absorbing sheet (3) ... Sound absorbing laminated body (3a) ... Tubular sound absorbing chamber (4) ... Back plate

Front Page Continuation (72) Inventor Yoshio Fukuda 1 43-1, Minamijimacho, Sakai City, Osaka Prefecture Osaka Filter Industry Co., Ltd. (72) Takashi Ikebe 1 43-1, Minamijimacho, Sakai City, Osaka Prefecture Osaka Within Filter Industry Co., Ltd. (72) Inventor Toshiyuki Morioka 1-43-1, Minamijimacho, Sakai City, Osaka Prefecture Within Osaka Filter Industry Co., Ltd.

Claims (5)

[Claims] 1. A back side sound absorbing laminate having a back side plate, a plurality of back side side sound absorbing chambers attached to the surface of the back side plate, and opening to the opposite side of the back side plate, and the back side side tubular sound absorbing device. A porous intermediate sound-absorbing sheet laminated on an opening surface for opening a chamber, and an upper sound-absorbing laminate having a plurality of upper tubular sound-absorbing chambers laminated on the porous intermediate sound-absorbing sheet and opened on the front and back sides, and an upper sound-absorbing layer. A sound absorber, comprising a porous surface-side sound-absorbing sheet laminated on a front-side opening surface of the laminate. 2. An upper sound-absorbing laminate having a plurality of tubular sound-absorbing chambers opened on the front and back, and a porous sound-absorbing sheet laminated on the front-side opening surface of the upper sound-absorbing laminate are alternately laminated in plural layers. The sound absorbing body according to claim 1, wherein the sound absorbing body is provided. 3. The sound absorbing body according to claim 1, wherein the height of the sound absorbing laminated body is different for each sound absorbing laminated body. 4. The sound absorbing body according to claim 1, wherein the sound absorbing sheet has a higher porosity as it is closer to the back plate side. 5. The sound absorbing body according to claim 1, wherein the sound absorbing sheet has irregularities formed on its surface.