WO2019138884A1

WO2019138884A1 - Sound-proofing structure, sound-proofing enclosure, and sound-proofing box

Info

Publication number: WO2019138884A1
Application number: PCT/JP2018/047879
Authority: WO
Inventors: 昇吾山添; 真也白田; 知佳松岡
Original assignee: 富士フイルム株式会社
Priority date: 2018-01-10
Filing date: 2018-12-26
Publication date: 2019-07-18
Also published as: JPWO2019138884A1; JP6959996B2

Abstract

This sound-proofing structure has: a honeycomb core; a first surface plate and a second surface plate which sandwich the honeycomb core; through-holes perforated in the first surface plate; and a sound absorbing body arranged on one surface of the first surface plate, the one side being located on the honeycomb core side, wherein the opening ratio of the through-holes in the first surface plate is at least 1.0%. This sound-proofing enclosure and sound-proofing box use the sound-proofing structure. This sound-proofing structure can achieve a sturdy and lightweight sound-proofing box capable of broadband sound absorption and having improved sound absorbing performance.

Description

Soundproof construction, soundproof enclosure and soundproof box

The present invention relates to a soundproofing structure, a soundproofing surrounding structure, and a soundproofing box, and more specifically, a sound absorbing body is provided on one surface located on the honeycomb core side of a face plate having through holes in one of two face plates sandwiching a honeycomb core. The present invention relates to a disposed soundproof structure, a soundproof surrounding structure using the same, and a soundproof box.

Since a box using a honeycomb board as a wall material is lightweight and has high rigidity, it is used as a soundproof box that can be easily installed. However, when the sound absorbing material is not disposed inside the box, there is a problem that the reverberation in the box becomes large and a problem that the sound reflected inside the box leaks out of the box, so the soundproof performance of the box is deteriorated. .
On the other hand, when arranging a sound absorbing material on the wall of a box, it is necessary to arrange a thick sound absorbing body in order to enhance the sound absorbing effect. Therefore, the soundproofness of the soundproof box is enhanced, but the volume inside the box is reduced.
For this reason, the wall of such a box is constituted by a honeycomb structure, and one surface plate of the surface plate covering both sides of the honeycomb core is made a porous material (see Patent Document 1), or a plurality of It is set as a perforated surface plate provided with a through-hole, and while achieving weight reduction compared with before by providing a sound absorbing material and / or a sound insulating material on this perforated surface plate (refer to

patent documents

2, 3, 4, 5). And improve the sound insulation performance such as sound absorption coefficient.

For example, Patent Document 1 proposes a sound absorber in which a porous material made of a paper material having a predetermined porosity is disposed on a honeycomb utilizing Helmholtz resonance of the honeycomb.
Patent Document 2 proposes that a fine through-hole corresponding to a honeycomb cell is formed in a surface plate bonded on a honeycomb to constitute a Helmholtz sound absorbing structure, and further, to bond an unwoven fabric on the upper surface thereof. With this structure, the sound absorbing effect can be added while maintaining high rigidity, and the sound absorbing frequency band can be expanded by the non-woven fabric.
Also in

Patent Documents

3, 4 and 5, a fine through hole corresponding to a honeycomb cell is formed in a face plate adhered on a honeycomb to constitute a sound absorbing structure, and a sound absorbing material and / or a sound insulating material is further formed on the upper surface thereof. It is proposed to provide. With this structure, the sound insulation effect can be enhanced while maintaining high rigidity, and the sound insulation effect can be further enhanced by the sound absorbing material and / or the sound insulating material.

Japanese Patent Application Laid-Open No. 09-228506 JP, 2017-065026, A Japanese Patent Application Laid-Open No. 09-221849 JP, 2017-151256, A JP 2012-241435 A

By the way, in the sound absorbing structure disclosed in Patent Document 1, there is a problem that when the porous material made of paper material is disposed immediately above the honeycomb, the rigidity of the board is reduced.
Further, in the sound absorbing structure disclosed in

Patent Documents

1 and 2, there is a problem that the frequency band in which soundproofing can be performed is narrow because Helmholtz resonance is used. In the soundproof structure disclosed in Patent Document 2, the sound absorption frequency band is expanded by the non-woven fabric, but there is a problem that there is a limit.
Further, even in the sound absorbing structures disclosed in

Patent Documents

3, 4 and 5, since the resonance is used, the frequency band that can be soundproofed is narrow, and the sound insulation effect is further improved by the sound absorbing material and / or the sound insulating material. There is a problem that it is widening, but has limitations.
That is, the sound absorbing structures disclosed in Patent Documents 1 to 5 have a problem in that they can not be both light in weight and high in rigidity and soundproof in a wide band.
Further, in the sound absorbing structure disclosed in Patent Documents 2 to 5, since the sound absorbing material and / or the sound insulating material are on the surface, an external object can directly contact the sound absorbing material and / or the sound insulating material. There was a problem that the sound insulation material was damaged.
Further, in the sound absorbing structures disclosed in Patent Documents 2 to 5, there is a problem that since the sound absorbing material and / or the sound insulating material are visually recognized, it is impossible to overcome the appearance problems such as the aesthetics.

The object of the present invention is to solve the above-mentioned problems of the prior art and to form a plurality of through holes in one of the face plates of the face plates on both sides of the honeycomb core and between the face plate having the through holes and the honeycomb core It is an object of the present invention to provide a soundproof structure capable of realizing both light weight and high rigidity and broad-band soundproofing by arranging a sound absorber.
Another object of the present invention is to provide a soundproof surrounding structure and a soundproofing box which is robust and lightweight, is capable of broad band sound absorption, and has an improved sound absorption performance by using the soundproof structure having the above effect. It is in.

Here, in the present invention, "sound insulation" includes the meanings of "sound insulation" and "sound absorption" as acoustic characteristics, but in particular means "sound insulation". Also, "sound insulation" refers to "shielding the sound". That is, "sound insulation" means "do not transmit sound". Therefore, “sound insulation” means including “reflecting” sound (reflection of sound) and “absorbing” sound (absorption of sound) (Sanshodo Daijinrin (third edition), and Japanese acoustics) See the materials society web page http://www.onzai.or.jp/question/soundproof.html, and http://www.onzai.or.jp/pdf/new/gijutsu201312_3.pdf).
In the following, basically, “reflection” and “absorption” are not distinguished, but both are referred to as “sound insulation” and “shielding”, and when both are distinguished, “reflection” and “absorption” are said. .

In order to achieve the above object, the soundproof structure according to the first aspect of the present invention comprises a honeycomb core, a first face plate sandwiching the honeycomb core, and a second face plate, and a through-hole perforated in the first face plate. And a sound absorber disposed on one surface of the first surface plate located on the honeycomb core side, and the aperture ratio of the through holes in the first surface plate is 1.0% or more.
In the present invention, the aperture ratio of the through holes is preferably 5% or more, more preferably 10% or more, and particularly preferably 20% or more.

Here, the diameter of the through hole is preferably 1.0 mm or more.
Moreover, it is preferable that the opening area of the through-hole of a 1st surface board is smaller than the opening area of a honeycomb core.
Moreover, it is more preferable that the opening area of the through-hole of a 1st surface board is smaller than 100 cm < ² >.
Further, it is preferable that the honeycomb cells of the honeycomb core sandwiched by the first front plate and the second front plate are hollow.
Further, the honeycomb cells of the honeycomb core sandwiched by the first front plate and the second front plate are hollow, and when the thickness of the honeycomb core is l, the thickness of the first front plate is h, and the aperture ratio is ar, It is preferable to satisfy the condition of the following inequality (1).
f ₁ (l, h) × ln (ar) + f ₂ (l, h) ≧ 1 (1)
Here, f ₁ (l, h) = A ₁ (h) × l ² + A ₂ (h) × l + 0.24915
f ₂ (l, h) = A ₃ (h) × l ² + A ₄ (h) × l + 1.804
A ₁ (h) = 19.466 × ln (h) -0.3038
A ₂ (h) = − 1.611 × ln (h) +4.0162
A ₃ (h) = 119.22 × ln (h) +78.249
A ₄ (h) =-5689.7 × h + 94.861
Further, the thickness l of the honeycomb core, the thickness h of the first surface plate, and the aperture ratio ar are more preferably satisfying the condition of the following inequality (1a), and most preferably satisfying the following inequality (1b).
f ₁ (l, h) × ln (ar) + f ₂ (l, h) ≧ 2 (1a)
f ₁ (l, h) × ln (ar) + f ₂ (l, h) ≧ 3 (1 b)
The honeycomb core is preferably made of paper, metal or resin.
The second front plate is preferably made of paper, metal or resin.
Preferably, the first front plate is made of paper, metal or resin.

The sound absorber is preferably made of a fine through hole plate, a woven cloth, a knit or a non-woven fabric.
The sound absorber preferably has a plurality of fine through holes penetrating in the thickness direction and having a diameter of 1.0 μm to 250 μm.
The sound absorber has a plurality of fine through holes penetrating in the thickness direction, and the average diameter of the fine through holes is 0.1 μm or more and less than 100 μm, and the average diameter of the fine through holes is phi (μm) The average aperture ratio rho of the fine through holes is in the range of greater than 0 and less than 1 when the thickness of t is t (μm), and rho_center = (2 + 0.25 × t) × phi−1.6 It is preferable that the upper limit is rho_center + (0.795 × (phi / 30) -2) with the lower limit of rho_center− (0.052 × (phi / 30) −2).
Further, the material of the sound absorber is preferably a flame retardant material.
The flame retardant material is preferably metal.
The metal is preferably aluminum or an aluminum alloy.
Further, the thickness of the sound absorber is preferably 50 mm or less.
The thickness of the sound absorber is more preferably 10 mm or less, still more preferably 5 mm or less, and most preferably 1 mm or less.

Further, it is preferable that the ventilation flow resistance of the sound absorber is 10 to 50000 Rayl.
Further, the total throughflow resistance of the throughflow portion R1 of the through hole of the first surface plate and the throughflow resistance R2 of the sound absorber is 12 Rayl or more, and preferably 16700 Rayl or less.
The total aeration flow resistance is 75 Rayl or more, more preferably 2570 Rayl or less, and more preferably 170 Rayl or more, and most preferably 1150 Rayl or less.
Furthermore, the first surface plate has a cover layer disposed on the side opposite to the sound absorber, and the air flow resistance R1 of the through hole of the first surface plate and the air flow resistance R2 of the sound absorber and the cover It is preferred that the total flow resistance of the aeration flow resistance R3 of the layer is 12 Rayl or more and 16700 Rayl or less.
The total aeration flow resistance is 75 Rayl or more, more preferably 2570 Rayl or less, and more preferably 170 Rayl or more, and most preferably 1150 Rayl or less.
Further, it is preferable that the ventilation flow resistance R2 of the sound absorber is larger than the ventilation flow resistance R3 of the cover layer.
Moreover, it is preferable that a cover layer consists of a fine through-hole board, a woven cloth, or a nonwoven fabric.
Moreover, it is preferable that the through-hole of two or more different hole diameters is opened by the 1st surface board.
Preferably, the first surface plate further has a small through hole having a diameter smaller than that of the through hole and having an opening ratio of less than 1.0%.
Moreover, it is preferable that a sound-absorbing body has a deodorizing function.
Furthermore, it is preferable to have a breathable cover layer disposed on one surface of the first face plate opposite to the side of the honeycomb core.

Moreover, the soundproofing surrounding structure of the 2nd aspect of this invention uses 2 or more of the soundproofing structures of the said 1st aspect.
Moreover, the soundproof box of the 3rd aspect of this invention has a soundproof surrounding structure of the said 2nd aspect.
The soundproof box of the third aspect of the present invention comprises the soundproof structure of the first aspect.
Here, it is preferable that a ventilating port for intake and exhaust be arranged.

According to the present invention, it is possible to provide a soundproof structure capable of realizing both light weight and high rigidity and wide-range soundproofing.
Furthermore, according to the present invention, it is possible to realize a soundproof surrounding structure and a soundproof box that are robust and lightweight, can perform wide-range sound absorption, and have improved sound absorption performance.
Further, according to the present invention, damage to the sound absorbing body can be prevented, and the appearance and the like can be improved.

It is a fragmentary sectional view showing typically an example of a soundproofing structure concerning one embodiment of the present invention. It is a top view which partially fractures and shows the soundproofing structure shown in Drawing 1 typically. It is sectional drawing which shows typically an example of the Helmholtz resonance structure used for this invention. It is a graph showing the aperture ratio dependence of the normal incidence sound absorption coefficient of the Helmholtz resonance structure shown in FIG. It is a graph showing the spectrum of the sound pressure of the Helmholtz resonance structure shown in FIG. It is a graph showing the noise level with respect to the aperture ratio of the Helmholtz resonance structure shown in FIG. It is a graph showing an example of the amount of reduction (noise level) which deducted the noise level in a soundproofing structure from the total noise amount (noise level) of pink noise. It is a graph showing another example of the amount of reduction (noise level) which deducted the noise level in a soundproofing structure from the total noise amount (noise level) of pink noise. It is a graph showing another example of the amount of reduction (noise level) which deducted the noise level in a soundproofing structure from the total noise amount (noise level) of pink noise. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the soundproof box which concerns on one Embodiment of this invention. It is a perspective view which shows the soundproof box shown in FIG. 7 typically. FIG. 7 is a cross-sectional view schematically showing a soundproof structure of Comparative Example 1; It is sectional drawing which shows the soundproof structure of the comparative example 2 typically. It is sectional drawing which shows the soundproof structure of the comparative example 3 typically. It is a graph which shows the relationship of the normal incidence sound absorption coefficient of the soundproof structure of Example 1 of this invention, and Comparative Examples 1-3, and a frequency. FIG. 21 is a perspective view schematically showing an example of a sound measurement system of the soundproof box of Example 11 of the present invention and Comparative Examples 11 to 13. It is a graph which shows the noise level inside the soundproof box of Example 11 of this invention, and Comparative Examples 11-13. FIG. 21 is a graph showing the difference in microphone sound pressure level inside the soundproof box of Example 11 of the present invention and Comparative Examples 12 to 13 with respect to Comparative Example 11. FIG. It is a graph which shows the noise level of the exterior of the soundproof box of Example 11 of this invention, and Comparative Examples 11-13. FIG. 16 is a graph showing the difference in microphone sound pressure level outside the soundproof box of Example 11 of the present invention and Comparative Examples 12 to 13 with respect to Comparative Example 11. FIG. It is a graph which shows the relationship of the normal incidence sound absorption coefficient and frequency of the soundproof structure of Examples 21-23 of this invention, and Comparative Examples 21-22. It is a graph which shows the relationship of the noise level of a soundproof structure of Examples 21-23 of this invention, and Comparative Example 21, and an aperture ratio. It is a fragmentary sectional view showing typically an example of the soundproofing structure concerning other embodiments of the present invention. It is a graph which shows the relationship of the normal incidence sound absorption coefficient of the soundproof structure of Example 1 of this invention, and the soundproof structure shown in FIG. 20, and a frequency. FIG. 21 is a top view schematically showing a measurement region for the soundproof honeycomb core shown in FIGS. 1 and 20. It is a top view which shows typically the structure in the measurement area | region of the honeycomb core of the soundproof structure shown in FIG.1 and FIG.20. It is a top view which shows typically an example (Example 31) of the sound-insulation structure which concerns on other embodiment of this invention. It is a side view which shows the soundproof structure (Example 31) shown in FIG. 24 typically. It is a top view which shows typically the soundproof structure of Example 32 which has a structure of the soundproof structure shown in FIG. It is a side view which shows typically the soundproof structure of Example 32 shown in FIG. It is a top view which shows the soundproof structure of comparative example 3 typically. It is a side view which shows typically the soundproof structure of the comparative example 3 shown in FIG. It is a graph which shows the relationship of the normal incidence sound absorption coefficient of the soundproof structure of Example 31-32 of this invention, and the comparative example 31, and a frequency. It is a top view which shows typically an example of the sound-insulation structure which concerns on other embodiment of this invention. It is a side view which shows the soundproof structure shown in FIG. 31 typically. It is a graph which shows the relationship of the normal incidence sound absorption coefficient of the soundproof structure of Example 41 of this invention, and a frequency. It is a graph which shows the relationship of the normal incidence sound absorption coefficient of the soundproof structure of Example 42 of this invention, and a frequency. It is a fragmentary sectional view showing typically an example of the shape of the penetration hole of the 1st surface board used for the present invention. It is a fragmentary sectional view showing typically another example of the shape of the penetration hole of the 1st surface board used for the present invention. It is a graph which shows the relationship of the normal incidence sound absorption coefficient of the soundproof structure of Example 51-52 of this invention, and a frequency.

Hereinafter, a soundproof structure, a soundproof surrounding structure using the same, and a soundproof box according to the present invention will be described in detail based on preferred embodiments shown in the attached drawings.
Although the description of the configuration requirements described below may be made based on the representative embodiments of the present invention, the present invention is not limited to such embodiments.
In the present specification, a numerical range represented using “to” means a range including numerical values described before and after “to” as the lower limit and the upper limit.

[Soundproof structure]
The soundproof structure according to the first embodiment of the present invention includes a honeycomb core, a first surface plate sandwiching the honeycomb core, a second surface plate, a through hole perforated in the first surface plate, and a honeycomb of the first surface plate. And a sound absorbing body disposed on one surface located on the core side, wherein the opening ratio of the through holes in the first face plate is 1.0% or more.
The soundproof structure of the present invention can realize light weight, high rigidity, and broad-band soundproofing.
The soundproofing structure of the present invention is robust and lightweight, and is capable of achieving a soundproofing surrounding structure and a soundproofing box that are capable of wide-band sound absorption and have improved sound absorption performance.
The soundproof structure of the present invention not only reduces the reverberation inside the soundproof box, but can also reduce the volume that leaks out.
The soundproof structure of the present invention can constitute a soundproof box with a simple box configuration by enhancing the sound absorption performance of the wall.

The soundproof structure of the present invention is, for example, inside or outside of a building or other structure (for example, a house, a hall, an elevator, a music classroom, a wall such as a meeting room, and a panel for ceiling), It can be used for transportation applications such as interior construction of automobiles, and for logistics applications such as box materials and packaging materials.
In addition, the soundproof structure of the present invention can be used for copying machines, blowers, air conditioners, ventilation fans, pumps, generators, ducts, and the like.
In addition, the soundproof structure of the present invention further includes industrial machines such as coating machines in factories, etc., and various types of manufacturing equipment that emits sounds such as rotating machines and conveying machines, vehicles such as automobiles, trains, etc. And use for general household appliances such as refrigerator, washing machine, dryer, television, copy machine, microwave oven, game machine, air conditioner, fan, PC (personal computer), vacuum cleaner, air purifier, and ventilation fan etc. Can.
In addition, the soundproof structure of this invention is suitably arrange | positioned in the position through which the sound generated from a noise source passes in these various apparatuses.

The soundproof structure according to the present invention will be described in detail with reference to FIGS. 1 and 2.
FIG. 1: is sectional drawing which shows typically an example of the sound-insulation structure which concerns on 1st Embodiment of this invention. FIG. 2 is a top view schematically showing the soundproof structure shown in FIG. 1 partially broken.
As shown in FIGS. 1 and 2, the soundproof structure 10 of the present invention comprises a honeycomb core 12 having a plurality of openings 14, a plate-like first surface plate 16 having a plurality of through holes 18, and a second surface. A face plate 20 and a sound absorber 22 are provided.
Here, the first front plate 16 and the second front plate 20 are arranged to sandwich the honeycomb core 12 with a space therebetween. The first surface plate 16 is bonded to one surface of the honeycomb core 12 via the sound absorber 22. The second surface plate 20 is bonded to the other surface of the honeycomb core 12. That is, the sound absorber 22 is disposed between the first surface plate 16 and the honeycomb core 12 (that is, one surface located on the honeycomb core side of the first surface plate). The sound absorbing body 22 is composed of a fine through hole plate 26 having a plurality of fine through holes 24 in the illustrated example.
In FIG. 2, in order to make the structure of the soundproof structure 10 easy to understand, the first surface plate 16 and the portion where the sound absorber 22 (fine through hole plate 26) is broken is shown on the left side of FIG. The part where only the face plate 16 is broken is shown in the middle of FIG.

[Honeycomb core]
The honeycomb core 12 is disposed between the first front plate 16 and the second front plate 20, is a frame having a plurality of honeycomb cells (frames), and has a plurality of openings 14 penetrating in the thickness direction. Have. That is, each honeycomb cell (frame) has an opening 14 respectively.
The plurality of openings 14 of the honeycomb core 12 are closed by the first face plate 16 disposed on both sides, the sound absorber 22 and the second face plate 20. Behind the through holes 18 of the first surface plate 16 and the fine through holes 24 of the fine through hole plate 26 which is the sound absorber 22, the opening 14 of the honeycomb core 12 is a closed space and a back air layer is formed. .
Here, it is preferable that the openings 14 of the honeycomb cells of the honeycomb core 12 sandwiched by the first front plate 16 and the second front plate 20 be hollow, and that nothing is filled in the openings 14. preferable. The reason for this is that even if it is a porous material in the opening 14 of the honeycomb core 12, it becomes heavy if the sound absorber is disposed. The hollow inside of the opening 14 of the honeycomb core 12 can provide a weight advantage.
Here, arranging a plurality of through holes 18 with respect to the first surface plate 16 so that one through hole 18 of the first surface plate 16 corresponds to one opening 14 of the honeycomb core 12. Is preferred. Therefore, it is preferable that the plurality of through holes 18 of the first front plate 16 be disposed corresponding to the plurality of openings 14 of the honeycomb core 12 respectively. When the plurality of openings 14 of the honeycomb core 12 are regularly arranged, the plurality of through holes 18 are also regularly arranged in the first surface plate 16 according to the plurality of openings 14 regularly arranged. Of course.

The arrangement of the plurality of openings 14 of the honeycomb core 12 and the arrangement of the plurality of through holes 18 of the first surface plate 16 are not limited to those described above. The two or more through holes 18 of the first surface plate 16 may be arranged to correspond to the openings 14 of the honeycomb core 12. The plurality of openings 14 may not be regularly arranged in the honeycomb core 12.
Further, the honeycomb core 12 preferably has a honeycomb structure. That is, the shape of the opening 14 is preferably a honeycomb (regular hexagonal) shape in a planar shape, but it is not particularly limited in the present invention. For example, the shape of the opening 14 may be a circle, an ellipse, a square (square), another rectangle such as a rectangle, a rhombus, or a parallelogram, a triangle such as an equilateral triangle, an isosceles triangle, or a right triangle. Alternatively, it may be a polygon including a regular polygon such as a regular octagon, an ellipse or the like, or it may be indeterminate. In the case where the shape of the opening 14 is a circle or a regular polygon such as a square, the diameter (pore diameter or size) of the opening 14 is the distance between opposing sides passing through the center or the circle equivalent diameter It can be defined, and in the case of a polygon, an ellipse, or an irregular shape, it can be defined as a circle equivalent diameter. In the present invention, the equivalent circle diameter and the radius are respectively a diameter and a radius when converted to a circle having the same area.

Here, as shown in FIG. 1, the diameter (size) of the opening 14 of the honeycomb core 12 is larger than the diameter of the through hole 18 of the first surface plate 16. The diameter of the opening 14 can be said to be the size (for example, the width or the length) of the honeycomb cells of the honeycomb core 12.
The diameter of the opening 14 is preferably 1.0 mm to 500 mm, more preferably 5 mm to 250 mm, and particularly preferably 10 mm to 100 mm.
Here, the reason why the diameter of the opening 14 is preferably 1.0 mm to 500 mm is that if it is smaller than 1.0 mm, the air viscosity resistance at the side wall of the cylindrical honeycomb core 12 becomes high, and the sound absorption effect decreases. Also, it is difficult to manufacture. In addition, when the size is larger than 500 mm, the rigidity is reduced.
The opening ratio of the openings 14 of the honeycomb core 12 is preferably larger than the opening ratio of the through holes 18 of the first surface plate 16.
Note that the shape and / or diameter of the openings 14 (or honeycomb cells) may be the same and constant in all the openings 14 (or honeycomb cells), but may be different and different sizes ( Openings (honeycomb cells) of different shapes may also be included.
Further, the planar shape and the size (planar size) of the honeycomb core 12 are not particularly limited, and may be appropriately determined in accordance with the planar shape, the size, and the like of the first surface plate 16 or the second surface plate 20. And choose.

The thickness of the honeycomb core 12 is equal to the distance (separation distance) between the sound absorber 22 and the second surface plate 20, but since the thickness of the sound absorber 22 is thin, the first surface plate 16 and the second surface plate 20 Can be said to be approximately equal to the distance between the The thickness of the honeycomb core 12 is not particularly limited, and may be determined or selected according to the place where the soundproof structure 10 of the present invention is used and the environment. The thickness of the honeycomb core 12 is, for example, preferably 1.0 mm to 200 mm, more preferably 5 mm to 100 mm, and particularly preferably 10 mm to 50 mm.
Here, the reason why the thickness of the honeycomb core 12 is preferably 1.0 mm to 200 mm is that the rigidity is greatly reduced when the thickness is less than 1.0 mm, and when the thickness is more than 200 mm, the soundproof structure becomes thicker. However, there is no space for placement.

In addition, the material of the honeycomb core 12 is lightweight and has high rigidity, and the honeycomb core 12 can support the first surface plate 16 and the sound absorber 22, and between the sound absorber 22 and the second surface plate 20. It is not particularly limited as long as it can maintain a constant interval and configure an air column resonance structure with the second face plate 20. The material of the honeycomb core 12 may be, for example, a flammable material or a flame retardant material.
In the present invention, the flammable material refers to materials other than the following flame retardant materials, and examples thereof include resin materials such as paper, wood, and synthetic resin. Examples of paper include cardboard, boards and the like. As the resin material, for example, acrylic resin such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate, polyamideid, polyarylate, polyetherimide, polyacetal, polyetheretherketone, polyphenylene sulfide, polysulfone, polybutylene Terephthalate, polyimide, and triacetyl cellulose etc. can be mentioned.

In the present invention, a flame retardant material refers to a material other than the above-mentioned combustible material, but in the case of a building material, a non-combustible material defined in Building Standard Act Article 2, Item 9, Building Standard Act Enforcement Order 1 Refers to the quasi-combustible materials specified in item 5 and the flame-retardant materials specified in Article 1 item 6 of the same Article. These materials do not burn for more than 5 minutes after the start of heating when heat from a normal fire is applied, they do not cause deformation, melting, cracking and other damage harmful to fire protection, harmful to evacuation It is necessary to satisfy three points of no smoke or no gas generation.
As a flame retardant material, materials, such as a metal material, an inorganic material, a flame-retardant plywood, a flame-retardant fiber board, and a flame-retardant plastic board, can be mentioned, for example. As a metal material, aluminum, steel, titanium, magnesium, tungsten, iron, steel, chromium, chromium molybdenum, nichrome molybdenum, and these alloys etc. can be mentioned, for example. As an inorganic material, glass, concrete, a gypsum board, sapphire, ceramics, etc. can be mentioned, for example.
Moreover, it can be used as a flame retardant material by coating a flammable material with an aramid resin or the like.

Moreover, as a material of honeycomb core 12 other than these, the material containing carbon fiber, such as carbon fiber reinforced plastic (CFRP), carbon fiber, and glass fiber reinforced plastic (GFRP), can also be mentioned.
In addition, you may use combining the multiple types of material of these honey-comb cores 12. As shown in FIG.
It is preferable to use a metal such as aluminum as the material of the honeycomb core 12 because high fire resistance can be obtained. On the other hand, using paper as the material of the honeycomb core 12 is preferable because it can be easily incinerated and can be made lighter.
In addition, it is preferable to use a paper coated with an aramid resin because light weight and fire resistance can be obtained.
From the above, the honeycomb core 12 is preferably made of paper, metal, or resin.

Here, the thickness of the material of the honeycomb core 12 is such that the honeycomb core 12 is light in weight and has high rigidity, has rigidity capable of supporting the first surface plate 16 and the sound absorber 22, and the sound absorber 22 and the second It is not particularly limited as long as the space between the face plate 20 can be kept constant and the honeycomb core 12 can form an air column resonance structure with the second face plate 20. The thickness of the material of the honeycomb core 12 is, for example, preferably 0.001 mm (1 μm) to 5 mm, more preferably 0.01 mm (10 μm) to 2 mm, and 0.1 mm (100 μm) to 1.0 mm Is particularly preferred.
Here, the reason why the thickness of the material of the honeycomb core 12 is preferably 0.001 mm (1 μm) to 5 mm is that if it is less than 0.001 mm (1 μm), the rigidity decreases. If it exceeds 5 mm, the weight is increased, and the light weight merit of the honeycomb core 12 is lost.
A sound absorbing material such as a sound absorbing material made of fibers such as woven cloth, knitted fabric, non-woven fabric, or felt, or a porous material such as urethane is disposed in a part of the opening (honeycomb cell) 14 of the honeycomb core 12. It is good.

It is preferable that the sound absorber 22 and the honeycomb core 12, and the honeycomb core 12 and the second surface plate 20 be fixed without a gap. The fixing method of the sound absorbing body 22 and the honeycomb core 12 and the fixing method of the honeycomb core 12 and the second surface plate 20 are as long as the honeycomb core 12 can be fixed to the sound absorbing body 22 and the second surface plate 20. But it is not particularly restrictive. The fixing method may include, for example, a method using an adhesive or a method using a physical fixing tool.
In the method of using an adhesive, the adhesive is applied on the both surfaces (of the honeycomb cell) surrounding the opening 14 of the honeycomb core 12 and the sound absorber 22 and the second surface plate 20 are mounted thereon. Place and fix to the honeycomb core 12. As the adhesive, for example, epoxy-based adhesive (Araldite (registered trademark) (manufactured by Nichiban Co., Ltd.) and the like), cyanoacrylate-based adhesive (Aron Alpha (registered trademark) (manufactured by Toagosei Co., Ltd. and the like), and acrylic An adhesive etc. can be mentioned.
As a method of using a physical fixing tool, the sound absorber 22 or the first face plate 16, the sound absorber 22 and the second face plate 20, which are disposed so as to cover and sandwich the opening 14 of the honeycomb core 12 A method of holding the fixing member between the honeycomb core 12 and a fixing member such as a rod and fixing the fixing member to the honeycomb core 12 by using a fixing tool such as a screw or a screw can be mentioned.

[First surface board]
The first surface plate 16 has a plate shape and has a plurality of through holes 18 penetrating in the thickness direction. The first surface plate 16 functions as a protective layer of the sound absorber 22, prevents the sound absorber 22 from coming into direct contact with an external object, and can suppress mechanical damage of the sound absorber 22. Further, since the first surface plate 16 having the plurality of through holes 18 covers the sound absorber 22, the appearance of the sound absorber 22 can be improved by the first surface plate 16 in design.
The through holes 18 of the first surface plate 16 correspond to the openings 14 of the honeycomb core 12.
Behind the through holes 18 of the first surface plate 16 and the fine through holes 24 of the sound absorber 22 (fine through hole plate 26), the back air layer in the closed space is formed by the honeycomb core 12 and the second surface plate 20. It is formed. The honeycomb core 12 forming the through holes 18 and the back air layer behind them and the second surface plate 20 constitute an air column resonance structure. That is, the portion of the honeycomb core 12 having one opening 14 and the portion of the second face plate 20 corresponding to the one opening 14 constitute an air column resonance structure. Here, the through holes 18 of the first face plate 16 are large holes that do not interfere with air column resonance (do not induce Helmholtz resonance). Further, the sound absorber 22 does not constitute air column resonance itself, but adds resistance to the air column resonance structure to widen the sound absorption band.
Here, although the plurality of through holes 18 may be arranged in the first surface plate 16, it may be regularly arranged according to the plurality of openings 14 of the honeycomb core 12. preferable. One through hole 18 may be provided in the first surface plate 16.

In the present invention, the thickness of the first face plate 16 is not particularly limited as long as the sound absorber 22 can be protected. The thickness of the first surface plate 16 is, for example, preferably 0.01 mm to 50 mm, more preferably 0.1 mm to 30 mm, and particularly preferably 1.0 mm to 10 mm.
The planar shape and the size (planar size) of the first front plate 16 are not particularly limited, and may be appropriately determined according to the place where the soundproof structure 10 using the first front plate 16 is used, the environment, and the like. You just have to choose it.

In the present invention, the plurality of through holes 18 of the first surface plate 16 are preferably arranged to correspond to the plurality of openings 14 of the honeycomb core 12 respectively. In particular, it is preferable that one through hole 18 of the first surface plate 16 and one opening 14 of the honeycomb core 12 be arranged in one-to-one correspondence. However, the present invention is not limited thereto, and if it does not disturb the air column resonance constituted by the honeycomb core 12 and the second surface plate 20 (does not induce the Helmholtz resonance), one opening of the honeycomb core 12 Two or more through holes 18 may be provided to 14. In the present invention, the plurality of through holes 18 of the first front plate 16 are preferably regularly arranged, but may be randomly (irregularly) arranged.
The shape of the through hole 18 is preferably planar and circular, but is not particularly limited in the present invention. For example, the shape of the through hole 18 may be a square (square), another rectangle such as a rectangle, a rhombus, or a parallelogram, a triangle such as an equilateral triangle, an isosceles triangle or a right triangle, an equilateral pentagon, or an equilateral hexagon It may be a polygon including a regular polygon, or an ellipse or the like, or it may be indeterminate. The diameter of the through hole 18 can be defined in the same manner as the diameter (size) of the opening 14.

The diameter of the through hole 18 of the first surface plate 16 is preferably 1.0 mm or more, more preferably 5 mm or more, and still more preferably 10 mm or more. The diameter of the through hole 18 is preferably 100 mm or less, more preferably 50 mm or less, and particularly preferably 25 mm or less.
Here, the reason for limiting the preferable range of the diameter of the through hole 18 to 1.0 mm or more is that, when the diameter of the through hole 18 is smaller than 1.0 mm, the viscous resistance at the side wall of the through hole 18 becomes large. When 22 is disposed under the first front plate 16, the acoustic resistance becomes too large, and the sound absorption characteristic is deteriorated.
Moreover, the reason for limiting the preferable range of the diameter of the through hole 18 to 100 mm or less is because the rigidity of the soundproof structure is lowered when the diameter is larger than 100 mm.

The shape and / or diameter of the through holes 18 may be constant in all the through holes 18 but may include different sizes (including different shapes).
That is, through holes 18 of two or more different hole diameters may be opened (perforated) in the first surface plate 16.
Furthermore, in addition to the through holes 18, the first surface plate 16 may have small through holes having a diameter smaller than that of the through holes 18 and having an opening ratio of less than 1.0%.
In the present invention, the diameter of the through hole 18 of the first surface plate 16 is larger than the diameter of the fine through hole 24 of the fine through hole plate 26 which is the sound absorbing body 22, and the penetration of the first surface plate 16 is also possible. The aperture ratio of the holes 18 is larger than the aperture ratio of the fine through holes 24 of the sound absorber 22.
In addition, the opening area of the through holes 18 of the first surface plate 16 is preferably smaller than the opening area of the openings 14 of the honeycomb core 12, and more preferably smaller than 100 cm ² .
The reason for this is that when the opening area is large as described above, the strength of the first surface plate 16 which is a perforated plate is reduced, and as a result, the strength of the sound absorbing structure is also reduced.

The opening ratio of the through holes 18 of the first surface plate 16 is the ratio of the area of the through holes 18 to the area of the closed space (back air layer) described above, that is, the cross sectional area of the honeycomb cells of the honeycomb core 12 (the area of the openings 14). It can be defined as the ratio of the hole area of the through hole 18 of the first front plate 16 to the When the openings 14 of the honeycomb core 12 are not constant or when the through holes 18 are not constant, the aperture ratio of the through holes 18 can be defined as the average aperture ratio of the through holes 18. The average aperture ratio of the through holes 18 can be determined as the total area ratio of all through holes 18 (the ratio of the total area of all through holes 18) to the area of the entire opening 14 of the honeycomb core 12. The area of all the openings 14 of the honeycomb core 12 may be obtained from the product of the average diameter and the number by calculating the average diameter and the number of the all openings 14 within the predetermined range of the honeycomb core 12. Further, the area of all the through holes 18 of the first surface plate 16 may be determined from the product of the average diameter and the number by calculating the average diameter and the number of all the through holes 18 within the predetermined range of the first surface plate 16 .
Here, in the present invention, the aperture ratio of the through hole 18 needs to be 1.0% or more. The opening ratio of the through holes 18 is preferably 5% or more, more preferably 10% or more, and particularly preferably 20% or more. Here, the reason why the aperture ratio is 1.0% or more is that, when the aperture ratio of the through hole 18 of the first surface plate 16 is 1.0% or more, the air weight by the air weight of the through hole 18 and the honeycomb core 12 This is because Helmholtz resonance consisting of a spring hardly occurs, air column resonance determined by the length of the air column of the honeycomb core occurs, and sound absorption in a wide band becomes possible. Note that an aperture ratio of 5% or more is preferable in order to realize broadband sound absorption.
Also, from the viewpoint of rigidity, the aperture ratio is preferably 90% or less, more preferably 80% or less, still more preferably 70% or less, and particularly preferably 50% or less.

The reason why the aperture ratio of the through holes 18 is more preferably 5% or more can be considered as follows.
The dependence of the aperture ratio of the normal incidence sound absorption coefficient of the Helmholtz resonance structure as shown in FIG. 3 (the ratio of the area of the through hole to the area of the closed space) is determined by calculation. It was calculated how much the noise level dropped.
The Helmholtz resonance structure 28 shown in FIG. 3 can also be said to be the one cell of the soundproof structure 10 of the present invention shown in FIG. The Helmholtz resonance structure 28 has a honeycomb core 12 having an opening 14, a first face plate 16 having a through hole 18, and a second face plate 20. In FIG. 3, a indicates the radius of the through hole 18, w indicates the diameter of the opening 14, h indicates the thickness of the first surface plate 16, and l indicates the thickness of the honeycomb core 12.

FIG. 4 shows the calculation results of the normal incidence sound absorption coefficient when the aperture ratio ar (= 4a ² / w ² ) of such a Helmholtz resonance structure 28 is changed. 4, the radius a of the through hole 18 is 0.0005 m (0.5 mm), the thickness l of the honeycomb core 12 is 0.03 m (30 mm), and the thickness h of the first surface plate 16 is 0.. This is the case of 001 m (1 mm).
It can be seen that as the aperture ratio ar increases, the frequency of the peak of the normal incidence sound absorption coefficient shifts to the high frequency side, and the band spreads. This is because the inductance component by the through hole 18 is large and the Helmholtz resonance is induced when the aperture ratio ar is small, whereas when the aperture ratio ar becomes large, the inductance component becomes smaller and air column resonance is mainly induced. It is because
When the muffling effect in this sound absorption spectrum is multiplied by pink noise (ar = 0), a spectrum of sound pressure levels as shown in FIG. 5 is obtained.

This sound pressure level is integrated in the range of 100 to 20000 Hz as the high frequency is the limit 20000 Hz of the audible range and the low frequency is the low frequency region where the audibility is greatly reduced, the aperture ratio ar and the radius a of the through hole 18 Of the range of practical use (ar = 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, a = 0.5 mm, 1 mm, 1.5 mm, The noise level at 2 mm and 2.5 mm), the thickness h of the first face plate 16 and the thickness l of the honeycomb core 12 in the practical range (h = 0.5 mm, 1 mm, 2 mm, 5 mm, l It calculated by shaking by = 10mm, 20mm, 30mm, 40mm), and obtained 16 types of graphs showing the noise level to the aperture ratio ar.
One of the results is shown in FIG. 6A as a representative.
From the graph shown in FIG. 6A, it can be seen that the noise level decreases sharply when the aperture ratio is 5%. Also, it can be seen that the noise level decreases even though the amount of reduction decreases at 10%. Furthermore, it can be seen that at 20%, the bottom of the reduction amount comes to bottom. The remaining graphs showed similar results.
On the other hand, the upper limit of the aperture ratio is better for the muffling effect as the aperture ratio is higher, but if it is too large, the rigidity of the first surface plate is reduced, so 90% or less is preferable and 70% or less is more preferable. And 50% or less at which the muffling effect is saturated is most preferable.

The calculation method is as follows.
Assuming that the acoustic impedance of the Helmholtz resonance structure 28 is Zh, it can be expressed by the following equation (2).

R is the acoustic resistance in the through hole 18, and was set so that the sound absorption coefficient becomes 99.9% at the time of resonance (the imaginary part is 0).
ar is an aperture ratio, which is represented by the ratio of the area of the through hole 18 to the area of the closed space (ar = 4a ² / w ² ). h ′ is the thickness of the first surface plate 16 including the open end correction of the through hole 18. Also, ρ is the air density, c is the speed of sound, l is the length of the back space, and ω is the angular frequency.
The first term of the imaginary part indicates the inductance of the through hole 18, and the second term indicates the capacitance of the closed space. As the aperture ratio ar increases, the inductance component decreases, and the characteristics of air column resonance causing resonance in the capacitance component increase.

Using the acoustic impedance of the Helmholtz resonance structure 28, the normal incidence sound absorption coefficient α was calculated from the following equation (3).

Z _air = c c, ρ: density of air, c: sound velocity Also, let the sound pressure level of pink noise p be p = -10 log (f / fo) (set to fo = 1000 Hz) and make the above sound pressure level a linear value The noise level was calculated by changing the noise absorption effect.

The present inventors also show the following inequality (1) of the open area ratio of the through holes 18, the thickness of the honeycomb core 12, and the thickness of the first surface plate 16 from the calculation results of 16 types of graphs including FIG. 6B. We found a preferred relationship.
When the honeycomb cells of the honeycomb core 12 sandwiched by the first front plate 16 and the second front plate 20 are hollow, the thickness of the honeycomb core 12 is l, the thickness of the first front plate 16 is h, and the thickness of the through holes 18 is When the aperture ratio is ar, it is preferable to satisfy the condition of the following inequality (1).
f ₁ (l, h) × ln (ar) + f ₂ (l, h) ≧ 1 (1)
Here, f ₁ (l, h) = A ₁ (h) × l ² + A ₂ (h) × l + 0.24915
f ₂ (l, h) = A ₃ (h) × l ² + A ₄ (h) × l + 1.804
A ₁ (h) = 19.466 × ln (h) -0.3038
A ₂ (h) = − 1.611 × ln (h) +4.0162
A ₃ (h) = 119.22 × ln (h) +78.249
A ₄ (h) =-5689.7 × h + 94.861
Further, the thickness l of the honeycomb core, the thickness h of the first surface plate, and the aperture ratio ar are more preferably satisfying the condition of the following inequality (1a), and most preferably satisfying the following inequality (1b).
f ₁ (l, h) × ln (ar) + f ₂ (l, h) ≧ 2 (1a)
f ₁ (l, h) × ln (ar) + f ₂ (l, h) ≧ 3 (1 b)

For each of the 16 types of graphs determined above including FIG. 6A, the noise level in the soundproofing structure is subtracted from the total noise amount (noise level) of pink noise to obtain 16 types of graphs representing the amount of reduction, Three of them are shown in FIGS. 6B, 6C and 6D. In FIGS. 6B, 6C, and 6D, the thickness l of the honeycomb core 12 is 0.03 m (30 mm), 0.05 m (50 mm), and 0.01 m (10 mm). Have a thickness h of 0.001 m (1 mm), 0.0005 m (0.5 mm), and 0.005 m (5 mm).
From the graphs of FIG. 6B, FIG. 6C, and FIG. 6D, it can be seen that the noise level largely depends on the thickness l of the honeycomb core 12 and the thickness h of the first surface plate 16.
The equation on the left side of the above inequality (1) is the line of calculation in FIG. 6B.
It can be seen that the above inequality (1) defines the conditions under which a noise reduction effect of 1 dB or more can be obtained. Here, 1 dB or more is preferable, 1.5 dB or more is more preferable, and 2 dB or more is more preferable. Here, 1 dB is the minimum unit of dB, and represents that the total energy of noise is reduced by 10%, and 1.5 dB represents that the total energy of noise is reduced by 1.4%. Also, 2 dB represents that the total energy of the noise is reduced by 1.6%, and 3 dB represents that the total energy of the noise is reduced to half. Here, the reason that the inequality (1) is more preferably 1.5 dB or more is that the noise reduction can be felt by hearing.

Further, as a material of the first surface plate 16, the sound absorbing body 22 can be protected, and sound absorption is performed between the honeycomb core 12 and the first surface plate 16 so that the sound absorbing body 22 is supported on one surface of the honeycomb core 12. The material is not particularly limited as long as the body 22 can be held and the distance between the body 22 and the second surface plate 20 can be maintained constant, and the same material as the honeycomb core 12 can be used.
The material of the first surface plate 16 is such that the first surface plate 16 protects the sound absorber 22, and the honeycomb core 12 and the second surface plate 20 behind the through holes 18 of the first surface plate 16 It is only necessary to configure a column resonance structure.
The first front plate 16 is preferably made of paper, metal or resin.

[2nd surface board]
Next, the second surface plate 20 is spaced apart from the first surface plate 16 on the other surface of the honeycomb core 12 (the lower surface in FIG. 1; that is, the surface opposite to the side on which the sound absorber 22 is provided). Be done.
The second surface plate 20 is for sealing the other side (the lower side in FIG. 1) of the plurality of openings 14 of the honeycomb core 12, and the sound absorbing body 22 and the first surface plate 16 are interposed therebetween. It is for holding the honeycomb core 12.
The thickness of the second surface plate 20 is not particularly limited as long as the sound absorber 22 and the honeycomb core 12 can be supported between the second surface plate 20 and the first surface plate 16, but for example, it is preferable to be 0.01 mm to 50 mm. It is more preferably 0.1 mm to 30 mm, and particularly preferably 1 mm to 10 mm.
Further, the planar shape and the size (planar size) of the second surface plate 20 are not particularly limited, depending on the planar shape, the size, etc. of the first surface plate 16 or the sound absorber 22 and the honeycomb core 12. It may be determined appropriately and may be selected.

The material of the second surface plate 20 is not particularly limited as long as the sound absorber 22 and the honeycomb core 12 can be held between the first surface plate 16 and the same material as the first surface plate 16 is used. be able to. For example, as a material of the second surface plate 20, various metals such as paper, aluminum, and iron, and various resin materials such as polyethylene terephthalate (PET) can be used.
The second front plate 20 is preferably made of paper, metal or resin.
In addition, the second surface plate 20 may be a component member or wall or the like of various devices on which a soundproof structure is installed as long as the sound absorber 22 and the honeycomb core 12 can be sandwiched between the second surface plate 20 and the first surface plate 16. Good. That is, for example, when installing a soundproof structure consisting of the first surface plate 16, the sound absorber 22 and the honeycomb core 12 on a wall, the surface of the honeycomb core 12 opposite to the surface on which the first surface plate 16 is disposed. The wall may be used as the second surface plate 20 by arranging the frame so as to be in contact with the wall.

In the example described above, although the first surface plate 16, the honeycomb core 12, and the second surface plate 20 are separate members, the honeycomb core 12 and the second surface plate 20 may be integrated. . Alternatively, the sound absorber 22, the honeycomb core 12 and the second surface plate 20 may be integrated.
A member or the like in which the honeycomb core 12 and the second surface plate 20 are integrated can be manufactured, for example, by a 3D printer. Further, the member in which the sound absorber 22, the honeycomb core 12 and the second surface plate 20 are integrated is, for example, a member forming the sound absorber 22, the honeycomb core 12 and the second surface plate 20 integrally molded by a 3D printer. As will be described later, it can be manufactured by forming the fine through holes 24 in the member forming the sound absorber 22 with a laser.

[Sound absorber]
Next, the sound absorber 22 is disposed in contact with one surface (upper surface in FIG. 1) of the honeycomb core 12 and the other main surface (lower surface in FIG. 1) of the first surface plate 16. 1 is sandwiched between the surface plate 16 and the honeycomb core 12. The sound absorber 22 functions as an air column resonance structure a closed space behind a plurality of fine through holes of the sound absorber 22 formed by the honeycomb core 12 and the second surface plate 20.
The sound absorber 22 is preferably a fine through hole plate or a film having a plurality of fine through holes. Further, as the sound absorber 22, a sound absorber made of a woven fabric, a knitted fabric, a non-woven fabric, or a fiber such as felt, a porous material such as urethane, and the like can be mentioned.
In the example shown in FIG. 1, the sound absorber 22 is disposed between the first surface plate 16 and the honeycomb core 12, and only one surface (the lower surface in FIG. 1) located on the honeycomb core 12 side of the first surface plate 16. Is located in

In the example shown in FIG. 1, the sound absorber 22 is constituted by a fine through hole plate 26 having a plurality of fine through holes 24 penetrating in the thickness direction.
The plurality of fine through holes 24 of the fine through hole plate 26 preferably have an average diameter of 1.0 μm to 250 μm. The fine through holes 24 may be perforated regularly or randomly in the fine through hole plate 26 in shape, size (diameter) and arrangement. The diameter of the fine through holes 24 can be defined in the same manner as the diameter of the through holes 18.
The reason why the average diameter of the fine through holes 24 is preferably 1.0 μm to 250 μm is that if the average diameter is less than 1.0 μm, the acoustic resistance is too large and the sound absorption characteristics are deteriorated. This is because when it exceeds 250 μm, the inductance of the fine through holes 24 increases and the band narrows.
In addition, if the sound absorbing body 22 has a plurality of fine through holes 24 penetrating in the thickness direction, even if it is a film-like (film-like) fine through-hole plate 26, a fibrous fine through-hole plate 26 It may be In the case of the fibrous fine through hole plate 26, the space between the fibers can be regarded as the fine through hole 24. The fine through-hole plate 26 may have regularity or randomness in the fine through-hole plate 24, so it may be a fiber itself and may be a woven cloth or nonwoven cloth having various weaves.
The sound absorbing body 22 composed of the fine through hole plate 26 is more preferable because a high sound absorbing effect can be obtained even in a thin state.

In addition, although it is preferable that the shape of the fine through hole 24 is planar and circular, it is not particularly limited in the present invention. For example, the shape of the micro through hole 24 may be a rectangle, a rhombus, or another quadrilateral such as a parallelogram, a regular triangle such as an equilateral triangle, an isosceles triangle or a right triangle, a regular pentagon, or a regular hexagon. It may be a polygon including or oval or the like, or may be indeterminate.
The soundproof structure 10 of the present invention comprises a first face plate 16 having through holes 18 and an air column formed by a honeycomb core 12 and a second face plate 20 behind a sound absorber 22 comprising fine through hole plates 26. While improving the sound absorption performance by the resonance structure, there is an effect of broadening the sound absorption frequency.

In the soundproof structure 10 of the present invention, the average diameter of the plurality of fine through holes 24 formed in the fine through hole plate 26 is 0.1 μm or more and less than 100 μm, and the average aperture ratio of the fine through holes 24 is as follows. When it is within the range, the fine through-hole plate 26 alone can be independently formed without the resonance structure formed by the first surface plate 16 having the through holes 18, the honeycomb core 12, and the second surface plate 20, It can be functioned as a soundproof structure that produces a high sound absorption effect.
Assuming that the average diameter of the plurality of fine through holes 24 of the fine through hole plate 26 is phi (μm) and the thickness of the fine through hole plate 26 is t (μm), the average aperture ratio rho of the fine through holes 24 is It is a range larger than 0 and smaller than 1 and having rho_center = (2 + 0.25 × t) × phi ^−1.6 as a center, and rho_center + (0.795 × (0.72 × (phi / 30) ⁻² ) as a lower limit. phi / 30) ^-2 ) is the upper limit.

The fine through hole plate 26 of the present invention has fine through holes 24 with an average diameter of 0.1 μm or more and less than 100 μm with an average aperture ratio in the above range, so that fine through holes 24 when sound passes through the fine through holes 24 The sound is absorbed by the friction between the inner wall surface 24 and the air. That is, the fine through hole plate 26 is a back surface of the resonance structure formed by the first surface plate 16 having the through holes 18 and the honeycomb core 12 and the second surface plate 20 behind the fine through hole plate 26 itself. Sound absorption by resonance with the closed space of the layer can be performed together with sound absorption of the fine through hole plate 26 itself by a mechanism that is not resonance. Thus, the sound absorption in the minute through hole plate 26 is the sound absorption effect by air column resonance in the air space in the closed space, and the friction between the inner wall surface of the minute through hole 24 and air when sound passes through the minute through hole 24. Together with the sound absorption effect.

The sound absorbing mechanism of the sound absorbing body 22 itself comprising the fine through hole plate 26 is to the thermal energy of the energy of the sound due to the friction between the inner wall surface of the fine through hole 24 and the air when the sound passes through the fine through hole 24 Estimated to be a change in This mechanism is different from the mechanism by resonance because it is caused by the fine size of the fine through holes 24. A path that passes directly as a sound in air by the fine through holes 24 has a much smaller acoustic impedance than a path that is once converted to film vibration and then emitted again as a sound. Therefore, the sound is more likely to pass through the path of the fine through holes 24 than the membrane vibration. When passing through the fine through hole portion, the sound is concentrated and passed from the entire wide area on the fine through hole plate 26 to the narrow area of the fine through hole 24. The local velocity is extremely increased by the collection of sounds in the minute through holes 24. As the friction is correlated with the speed, the friction increases in the fine through holes 24 and is converted to heat.
When the average diameter of the fine through holes 24 is small, the ratio of the edge length of the fine through holes 24 to the opening area is large, so that the friction generated at the edges and / or the inner wall of the fine through holes 24 is increased. It is believed that By increasing the friction when passing through the fine through holes 24, it is possible to convert sound energy into heat energy and absorb sound.

In addition, an optimum ratio exists to the average aperture ratio of the fine through holes 24. In particular, when the average diameter is relatively large such as about 50 μm or more, the smaller the average aperture ratio, the higher the absorption rate. When the average aperture ratio is large, the sound passes through each of the many fine through holes 24, whereas when the average aperture ratio is small, the number of the fine through holes 24 decreases, so one fine The sound passing through the through hole 24 increases, and the local velocity of air passing through the fine through hole 24 is further increased, and the friction generated at the edge and the inner wall surface of the fine through hole 24 can be further increased. .

As described above, since the sound absorption by the fine through holes 24 themselves functions with the fine through hole plate 26 alone, the size can be freely set.
Further, as described above, since the sound absorption by the fine through holes 24 is absorbed by the friction when the sound passes through the fine through holes 24, the sound can be absorbed regardless of the frequency band of the sound, and the sound is absorbed in a wide band Can.
In addition, since the function is achieved by forming the fine through holes 24 in the fine through hole plate 26, the degree of freedom in selecting the material of the fine through hole plate 26 is high, and the problems of environmental pollution and environmental performance are also Problems can be reduced because materials can be selected together.
Further, since the fine through hole plate 26 has the fine through holes 24, even if a liquid such as water adheres to the fine through hole plate 26, the surface tension prevents water from avoiding the fine through holes 24. Since the fine through holes 24 are not closed, the sound absorption performance is unlikely to be reduced.
Further, since the fine through hole plate 26 is a thin layered film, it can be curved according to the place to be arranged.

Here, from the viewpoint of sound absorption performance etc., the upper limit value of the average diameter of the fine through holes 24 is less than 100 μm, preferably 80 μm or less, more preferably 70 μm or less, still more preferably 50 μm or less, and most preferably 30 μm or less. This is because the smaller the average diameter of the fine through holes 24, the larger the ratio of the length of the edge of the fine through holes 24 contributing to the friction to the opening area of the fine through holes 24, and the friction It is because it becomes easy to occur.
Moreover, 0.5 micrometer or more is preferable, as for the lower limit of an average diameter, 1.0 micrometer or more is more preferable, and 2.0 micrometers or more are still more preferable. If the average diameter is too small, the viscosity resistance at the time of passing through the fine through holes 24 is too high and the sound does not pass sufficiently. Even if the aperture ratio is increased, the sound absorbing effect can not be obtained sufficiently.

In addition, as described above, when the average diameter is phi (μm) and the thickness of the fine through hole plate 26 is t (μm), the average opening rate rho of the fine through holes 24 is the average opening rate of the fine through holes 24 The rho is a range of greater than 0 and less than 1 and rho_center = (2 + 0.25 × t) × phi ^−1.6 with rho_center− (0.052 × (phi / 30) ⁻² ) as the lower limit, rho_center + ( The upper limit is 0.795 × (phi / 30) ⁻² ).
Further, the average aperture ratio rho is preferably in the range of rho_center−0.050 × (phi / 30) ⁻² or more, rho_center + 0.505 × (phi / 30) ⁻² or less, and rho_center−0.048 × (phi / 30) ⁻² or more The range of rho_center + 0.345 × (phi / 30) ^-2 or less is more preferable, and the range of rho_center-0.085 × (phi / 20) ^-2 or more, rho_center + 0.35 × (phi / 20) ^-2 or less is more preferable, The range of (rho_center−0.24 × (phi / 10) ⁻² ) or more and (rho_center + 0.57 × (phi / 10) ⁻² ) or less is particularly preferable, and (rho_center−0.185 × (phi / 10) ⁻² ) or more, The range of (rho_center + 0.34 × (phi / 10) ⁻² ) or less is most preferable.

As described above, in the soundproof structure 10 of the present invention, when the average diameter of the plurality of fine through holes 24 formed in the fine through hole plate 26 which is the sound absorber 22 is 0.1 μm or more and less than 100 μm, the fine through holes 24 are formed. Setting the average aperture ratio rho in the above-mentioned range is to optimize the sound absorption coefficient (absorptivity when sound passes through the sound absorber 22) of the sound absorber 22 alone of the present invention. As described above, optimizing the sound absorption coefficient of the sound absorber 22 alone (the absorptivity when sound passes through the sound absorber 22) results in obtaining high acoustic resistance in the sound absorber 22. Therefore, like the soundproof structure 10 of the present invention, the first surface plate 16 having the through holes 18 with the fine through hole plate 26 having the fine through holes 24 satisfying the above range as the sound absorbing body 22; By using it with the honeycomb core 12, it is most suitable for obtaining broadband characteristics by the sound absorption of the fine through holes 24 themselves and the resonance in the air column resonance structure formed by the honeycomb core 12 and the second surface plate 20. Large acoustic resistance values can be added.

The average diameter of the fine through holes 24 is obtained by photographing the surface of the sound absorbing body 22 at a magnification of 200 times using a high resolution scanning electron microscope (SEM) from the surface side of the sound absorbing body 22. Then, 20 fine through holes 24 whose circumferences are annularly connected are extracted, their diameters are read, and their average value is calculated as an average diameter. If the number of micro through holes 24 is less than 20 in one SEM photograph, SEM photographs are taken at another position around the periphery and counted until the total number reaches 20.
In addition, a diameter measured the area of the part of the fine through-hole 24, respectively, and evaluated using the diameter (circle equivalent diameter) when replacing with the circle used as the same area. That is, since the shape of the opening of the fine through hole 24 is not limited to a substantially circular shape, when the shape of the opening is non-circular, the diameter of the circle having the same area was evaluated. Therefore, for example, even in the case of a fine through hole having a shape in which two or more fine through holes are integrated, this is regarded as one fine through hole 24 and the circle equivalent diameter of the fine through hole 24 is the diameter.
In these operations, for example, the circle equivalent diameter, the aperture ratio and the like can all be calculated by Analyze Particles using “Image J” (https://imagej.nih.gov/ij/).

In addition, the average aperture ratio is obtained by photographing the surface of the sound absorber 22 at a magnification of 200 times from directly above using a high resolution scanning electron microscope (SEM), and the field of view of 30 mm × 30 mm of the obtained SEM photograph (5 places) Of the fine through holes 24 and the non-fine through holes are binarized with image analysis software etc., and the ratio from the total of the open areas of the fine through holes 24 and the area of the field of view (geometrical area) It calculates from (opening area / geometrical area), and calculates the average value in each visual field (five places) as an average aperture ratio.

In addition, the plurality of fine through holes 24 may be formed of fine through holes 24 of one type of diameter as long as the average diameter is 1.0 μm to 250 μm, and fine through holes 24 of two or more types of diameters. It may consist of From the viewpoint of productivity, the viewpoint of durability, etc., it is preferable to be composed of fine through holes 24 of two or more diameters.
As for the productivity, if the variation in diameter is allowed from the viewpoint of performing a large amount of etching processing, the productivity is improved. Also, from the viewpoint of durability, the size of dust and dirt varies depending on the environment, so if it is a fine through-hole with a single diameter, all fine through-holes when the size of the main dust roughly matches the fine through-hole It will affect the holes. By providing micro through holes of a plurality of different diameters, the device can be applied in various environments.

Further, by the manufacturing method described in International Publication WO 2016/060037 or the like, it is possible to form a fine through hole having a diameter expanded inside the fine through hole and having the largest inside diameter. With this shape, dust (a dust, toner, non-woven fabric, loose foam, etc.) of about the size of fine through holes hardly gets blocked inside, and the durability of the fine through hole plate having fine through holes is improved.
Dust larger than the diameter of the outermost surface of the fine through hole does not intrude into the fine through hole, while dust smaller than the diameter can pass through the fine through hole as it is because the internal diameter is large.
Considering the reverse shape and the inside of the inside of the fine through hole, the dust passing through the outermost surface of the fine through hole is caught in the small diameter part of the inside, compared to the fact that the dust tends to remain as it is. It can be seen that the shape with the largest diameter at the above functions advantageously in the suppression of dust clogging.
Also, as in the so-called tapered shape, in the case where the diameter of one of the surfaces of the film is the largest diameter and the inner diameter decreases substantially monotonically, the largest diameter is "largest diameter> dust size> other surface" When the dust that satisfies the relationship of “diameter” enters, the internal shape functions like a slope and the possibility of clogging in the middle becomes even greater.

Also, from the viewpoint of increasing the friction when sound passes through the fine through holes, the inner wall surface of the fine through holes is preferably roughened. Specifically, the surface roughness Ra of the inner wall surface of the fine through hole is preferably 0.1 μm or more, more preferably 0.1 μm to 10.0 μm, and 0.2 μm or more and 1.0 μm or less Is more preferred.
Here, the surface roughness Ra can be measured by measuring the inside of the fine through holes with an AFM (Atomic Force Microscope). As the AFM, for example, SPA300 manufactured by Hitachi High-Tech Science Co., Ltd. can be used. The cantilever can be measured in DFM (Dynamic Force Mode) mode using OMCL-AC200TS. Since the surface roughness of the inner wall surface of the fine through hole is about several microns, it is preferable to use AFM in terms of having a measurement range and accuracy of several microns.

Further, from the SEM image in the fine through hole, it is possible to calculate the average particle diameter of the convex portion by regarding each of the convex portions of the unevenness in the fine through hole as particles.
Specifically, an SEM image (field of view of about 1 mm × 1 mm) taken at a magnification of 2000 × is taken into Image J, and binarized into black and white so that the convex part becomes white, and the area of each convex part is analyzed Calculated by Particles. The circle equivalent diameter which assumed the circle | round | yen which becomes the same area as each area is calculated | required about each convex part, and the average value is calculated as an average particle diameter.
The average particle diameter of the convex portion is preferably 0.1 μm or more and 10.0 μm or less, and more preferably 0.15 μm or more and 5.0 μm or less.

Here, the ventilation flow resistance of the sound absorber 22 (for example, the fine through hole plate 26 having the fine through holes 24) is preferably 10 to 50000 Rayl, more preferably 50 to 10000 Rayl, and 100 to 2000 Rayl. Is most preferred. Although the diameter of the through hole 18 is smaller than 10 Rayl, the sound absorption coefficient (viscous resistance) optimum for the first surface plate 16 having a small diameter and a small aperture ratio can be obtained, but if it is smaller than this, there is almost no resistance. On the other hand, if it exceeds 50000 Rayl, the resistance is too large and reflection mainly occurs to reduce the sound absorption effect.
The total throughflow resistance of the throughflow resistance R1 of the through hole 18 of the first surface plate 16 and the throughflow resistance R2 of the sound absorber 22 is 12 Rayl or more, and preferably 16700 Rayl or less. With such a total air flow resistance, a sound absorption effect of 10% or more can be obtained at the resonance frequency.
The total aeration flow resistance described above is 75 Rayl or more, more preferably 2570 Rayl or less, and more preferably 170 Rayl or more, and most preferably 1150 Rayl or less. A more preferable range of the above total vent flow resistance is a value at which a sound absorption effect of 50% or more is obtained at the resonance frequency, and a most preferable after range of the above total vent flow resistance is 80% or more at the resonance frequency It is a condition under which a sound absorption effect can be obtained.

Further, the ventilation flow resistance R1 of the portion of the through hole 18 of the first surface plate 16 is expressed by the following formula (4).

ρ: air density, c: sound velocity, ν: viscous drag of air, ω: angular frequency, t: thickness of surface plate, a: radius of hole According to this formula, the hole shape of through hole 18 of first surface plate 16 is obtained. It is possible to limit the flow resistance of the sound absorber 22 that is required.

Further, the thickness of the fine through hole plate 26 which is the sound absorbing body 22 is not limited. However, since the friction energy received when the sound passes through the fine through hole 24 increases with the thickness, the sound absorbing performance is further improved. Conceivable. Moreover, when it is extremely thin, it is difficult to handle it and it is easy to break it. On the other hand, it is preferable that the miniaturization, the air permeability and the light transmission be thin. In the case of using etching or the like for the method of forming the fine through holes 24, the longer the thickness, the longer the preparation time, and the thinner is desirable from the viewpoint of productivity.
When the thickness of the sound absorbing body 22 is increased, the rigidity of the first surface plate 16 having the honeycomb core 12 and the through holes 18 is reduced, so that the thinner one is preferable. Accordingly, the thickness of the sound absorber 22 is preferably 50 mm or less, more preferably 20 mm or less, still more preferably 10 mm or less, still more preferably 5 mm or less, and most preferably 1 mm or less.
On the other hand, if the thickness of the sound absorbing body 22 is too thin, the sound absorbing body 22 is susceptible to mechanical damage, so it is preferably 0.1 μm or more, more preferably 1 μm or more, and 10 μm or more. Is more preferred.
When the sound absorber is thick (for example, 1.0 mm or more), the distance between the first front plate 16 and the second front plate 20 becomes longer by the thickness of the sound absorber 22. can do. However, in this case, the thickness of the sound absorbing structure is increased.
The planar shape and the size (planar size) of the sound absorber 22 are not particularly limited, and may be appropriately determined according to the planar shape of the first front plate 16, the size, etc., and may be selected appropriately. .

Hereinafter, the case where the sound absorbing body 22 is a film-like (film-like) fine through hole plate 26 having a plurality of fine through holes 24 will be described.
The material of such a fine through hole plate 26 is not particularly limited, and the same material as the material of the honeycomb core 12 can be used. The material of the sound absorber 22 is, for example, aluminum, titanium, nickel, permalloy, 42 alloy, kovar, nichrome, copper, beryllium, phosphor bronze, brass, nickel, tin, zinc, iron, tantalum, niobium, molybdenum, zirconium, Gold, silver, platinum, palladium, steel, tungsten, lead, stainless steel, and various metals such as iridium; alloy materials of these metals; PET (polyethylene terephthalate), TAC (triacetyl cellulose), polyvinylidene chloride, polyethylene, poly Vinyl chloride, polymethyl bentene, COP (cycloolefin polymer), polycarbonate, ZEONOR, PEN (polyethylene naphthalate), polypropylene, and polyimide, ABS resin (acrylonitrile (Acrylonitrile), butadiene (Butadiene), styrene ( Resin materials such as Styrene) copolymer synthetic resin) and PLA resin can be used. Furthermore, glass materials such as thin film glass, CFRP (carbon fiber reinforced plastics), and fiber reinforced plastic materials such as GFRP (glass fiber reinforced plastics) can also be used.

The material of the sound absorber 22 is preferably a flame retardant material particularly when the first surface plate 16, the second surface plate 20, and the honeycomb core 12 are made of a flammable material such as paper. The flame retardant material is more preferably a metal material.
That is, it is more preferable to use a metal material from the viewpoints of high flame retardancy, high Young's modulus, low vibration even when the thickness is thin, and the effect of sound absorption by friction in fine through holes is easily obtained. preferable. Among them, copper, nickel, stainless steel, titanium and aluminum are more preferable from the viewpoint of cost and availability. In particular, it is most preferable to use aluminum and an aluminum alloy from the viewpoints of lightness, easy formation of minute through holes by etching and the like, availability and cost.
Moreover, when using a metal material, you may metal-plate on the surface from a viewpoint of suppression of rust etc.
Furthermore, the average diameter of the fine through holes may be adjusted to a smaller range by metal plating at least on the inner surface of the fine through holes.

Further, by using a conductive material such as a metal material which is not electrically charged as a material of the sound absorber 22, fine dust, dust and the like are not attracted to the film by static electricity, and the fine through hole plate 26 It is possible to suppress that the sound absorption performance is reduced due to dust, dirt and the like being clogged in the through hole 24.
Moreover, heat resistance can be made high by using a metal material as a material of a fine through-hole board. In addition, ozone resistance can be enhanced.
Moreover, when using a metal material as a material of a fine through-hole board, an electromagnetic wave can be shielded.

Further, since the metal material has a large reflectance to radiant heat by far infrared rays, the metal material (conductive material) is used as a material of the fine through-hole plate to also function as a heat insulating material for preventing heat transfer by the radiant heat. At this time, although a plurality of fine through holes are formed in the fine through hole plate, the fine through hole plate functions as a reflective film because the diameter of the fine through holes is small.
A structure in which a plurality of fine through holes are opened in metal is known to function as a high pass filter of frequency. For example, a window with a metal mesh of a microwave oven has a property of shielding visible light that is high frequency while passing microwaves used in the microwave oven. In this case, when the diameter of the fine through hole is Φ and the wavelength of the electromagnetic wave is λ, the long wavelength component in the relationship of << λ does not pass, and the short wavelength component with Φ> λ functions as a transmitting filter.
Now consider the response to radiant heat. Radiant heat is a heat transfer mechanism in which far infrared rays are emitted from an object in accordance with the object temperature and transmitted to another object. From the Wien's radiation law, radiant heat is distributed around λ = 10 μm in a room temperature environment, and heat is effectively radiated up to a wavelength about 3 times (up to 30 μm) on the long wavelength side It is known to contribute to Considering the relationship between the diameter Φ of the high-pass filter and the wavelength λ, the component of λ> 20 μm is strongly shielded in the case of == 20 μm, while the relationship of >> λ is obtained in the case of == 50 μm. It propagates through That is, since the diameter Φ is several tens of μm, the radiation heat propagation performance largely changes depending on the difference in the diameter Φ, and it can be seen that the smaller the diameter Φ, that is, the smaller the average diameter, the function as a radiation heat cut filter. Therefore, from the viewpoint of a heat insulating material that prevents heat transfer due to radiant heat, the average diameter of the fine through holes formed in the fine through hole plate is preferably 20 μm or less.

On the other hand, when transparency is required for the entire soundproof structure, a resin material or glass material that can be made transparent can be used. For example, a PET film has relatively high Young's modulus among resin materials, is easily available, and has high transparency, so that fine through holes can be formed to provide a suitable soundproof structure.
In addition, the micro through-hole plate is appropriately subjected to surface treatment (plating treatment, oxide film treatment, surface coating (fluorine, ceramic), etc.) according to the material thereof to improve the durability of the micro through-hole plate. be able to. For example, in the case of using aluminum as the material of the fine through hole plate, an oxide film can be formed on the surface by performing an alumite treatment (anodic oxidation treatment) or a boehmite treatment. By forming an oxide film on the surface, corrosion resistance, abrasion resistance, abrasion resistance and the like can be improved. Further, by adjusting the treatment time and adjusting the thickness of the oxide film, it is possible to adjust the color tone by optical interference.

Moreover, coloring, decoration, decoration, design, etc. can be given to a fine through-hole board. As a method of applying these, an appropriate method may be selected depending on the material of the fine through hole plate and the state of surface treatment. For example, printing using an inkjet method can be used. Moreover, when using aluminum as a material of a fine through-hole board, coloring with high durability can be performed by performing a color alumite process. The color alumite treatment is a treatment in which the surface is subjected to alumite treatment, then impregnated with a dye, and then the surface is sealed. By this, it can be set as the fine through-hole board with high designability, such as the presence or absence and color of metallic luster. In addition, by performing anodizing after forming the fine through holes, the anodized film is formed only on the aluminum portion, so that the dye covers the fine through holes and the decoration is performed without reducing the sound absorption characteristics. It can be performed.
By combining with the above-mentioned alumite treatment, various colors and designs can be added.

Next, the case where the fine through hole plate is a fibrous film will be described.
As mentioned above, the fine through hole plate may be a woven fabric, or a fiber itself such as a knit, or a fibrous film such as a non-woven fabric. In the case of fibrous membranes, the spaces between the fibers can be regarded as through holes.
In addition, when the fibers themselves are in the form of a film, the fibers are irregularly overlapped, and in the case of the non-woven fabric, the fibers are irregularly woven, so the fibers are not parallel or orthogonal to each other. A through hole is formed in the space surrounded by Accordingly, the fiber diameter and the density determine the average diameter and the average opening ratio of the fine through holes.
250 micrometers or less are preferable and, as for the thickness in case a fine through-hole board is a fibrous film | membrane, 100 micrometers or less are more preferable.
The fiber diameter of the fibrous film is usually about several tens of μm. Therefore, many yarns will not be laminated | stacked by making thickness into 100 micrometers or less. Therefore, the space surrounded by the fibers can be regarded almost like a through hole. By this, even if it is a fibrous member, it can handle a sound absorption characteristic like a plate-like member which has a penetration hole.

The material of the fibrous film includes aramid fiber, glass fiber, cellulose fiber, nylon fiber, vinylon fiber, polyester fiber, polyethylene fiber, polypropylene fiber, polyolefin fiber, rayon fiber, low density polyethylene resin fiber, ethylene vinyl acetate resin fiber , Fiber made of resin material such as synthetic rubber fiber, copolyamide resin fiber, copolyester resin fiber, etc .; paper (tissue paper, Japanese paper etc.); SUS fiber (stainless fiber sheet manufactured by Yodogawa Paper Co., Ltd. "Tomy Fileck" Fibers made of a metal material such as “SS” etc.); fibers of a carbon material, fibers of a carbon-containing material, and the like.
Since the absorption characteristic in the present invention is generated when sound passes through the fine through holes, the acoustic characteristics hardly change even if the material of the fibrous member changes. Thus, the material can be selected freely. Moreover, it can also select according to characteristics other than an acoustic characteristic. For example, if heat resistance is required, a metal material can be selected, and if weight reduction is required, a plastic material can be selected.

Further, the sound absorber 22 and the first front plate 16 may be disposed in contact with each other, but it is preferable that they be adhered and fixed.
By bonding and fixing the sound absorber 22 and the first surface plate 16, the rigidity of the sound absorber 22 can be made higher, and the resonance vibration frequency can be made higher.
The adhesive used to bond and fix the sound absorber 22 and the first surface plate 16 may be selected according to the material of the sound absorber 22 and the material of the first surface plate 16 or the like. As the adhesive, for example, epoxy-based adhesive (Araldite (registered trademark) (manufactured by Nichiban Co., Ltd.) and the like), cyanoacrylate-based adhesive (Aron Alpha (registered trademark) (manufactured by Toagosei Co., Ltd. and the like), and acrylic A system adhesive etc. can be mentioned.

Further, it is preferable that the sound absorber 22 have a deodorizing function.
When the sound absorbing body 22 is provided with a deodorizing function, in the case where the sound absorbing body 22 is a fibrous film, a fine through hole plate, or a porous material, it is sufficient to impregnate the deodorant in each of the fibers. .
As a deodorant, a well-known deodorant can be used. Deodorants include, for example, odor-free air and cloth deodorant mist made by Kobayashi Pharmaceutical Co., Ltd., Orbuse's Revenge Natural Caribbean Rush Up Spray (CR-TN012), Goodwill Biol Will Clear Spray E483184H) and the like.

The soundproof structure of the present invention can be used as a soundproofing member as described below in addition to the above.
For example, as a soundproof member having the soundproof structure of the present invention,
Soundproofing materials for building materials: Soundproofing materials used for building materials,
Soundproofing members for air conditioning equipment: Soundproofing members installed in ventilation openings and air conditioning ducts to prevent external noise,
Soundproof member for external opening: A soundproof member installed in the window of a room to prevent noise from indoor or outdoor,
Soundproofing material for ceiling: A soundproofing material installed on the ceiling of the room to control the sound in the room,
Floor soundproofing members: Soundproofing members installed on the floor that control the sound in the room,
Soundproofing members for internal openings: Soundproofing members installed on indoor doors or bran to prevent noise from each room,
Soundproofing material for toilets: Installed in the toilet or in the door (outdoor), a soundproofing material to prevent noise from the toilet,
Soundproofing material for balconies: A soundproofing material installed on the balcony that prevents noise from your own balcony or the next balcony.
Interior adjustment members: soundproof members for controlling the sound of a room,
Simple soundproof room member: A soundproof member that can be easily assembled and moved easily
Soundproof room for pets: A soundproofing unit that encloses the pet room and prevents noise.
Amusement facilities: Soundproof members installed in game centers, sports centers, concert halls, movie theaters, etc.
Soundproofing members for temporary construction enclosures: Soundproofing members that cover the construction site and prevent noise from leaking around,
Soundproofing members for tunnels: Soundproofing members installed in a tunnel to prevent noise leaking to the inside and the outside of the tunnel can be mentioned.
The soundproof structure of the first embodiment of the present invention is basically configured as described above.

[Soundproof box]
The soundproof structure according to the first embodiment of the present invention can be used as it is, for example, in building applications such as inside or outside of buildings, other structures, transportation applications, and logistics applications, but the present invention is limited thereto Instead, a soundproof enclosure using two or more soundproof structures may be used, a soundproof box using a soundproof structure may be used, or a soundproof box using a soundproof enclosure may be used.
FIGS. 7 and 8 are a cross-sectional view and a perspective view schematically showing an example of a soundproof box according to a second embodiment of the present invention.
The soundproof box 30 shown in FIGS. 7 and 8 uses five soundproof structures 10 shown in FIGS. 1 and 2, and the second face plate 20 of each soundproof structure 10 is on the front side (outside), therefore, Table 1 It joins so that the face plate 16 may become a back side (inner side), and is comprised in rectangular solid shape.
The soundproof box 30 according to the second embodiment of the present invention is a soundproof box surrounded by the soundproof structure 10 according to the first embodiment of the present invention. By sandwiching the first and

second face plates

16 and 20, a high rigidity and a high sound absorption effect can be achieved by arranging the first face plate 16 with the through holes 18 open inside the soundproof box 30. Can be obtained by

In order to form the soundproof box 30 shown in FIG. 8 from the five soundproof structures 10, first, as shown in FIG. 7, both ends of the first face plate 16 of the two soundproof structures 10, the remaining two soundproof structures 10 Are bonded and fixed to the side surfaces of the first surface plate 16, the sound absorber 22, the honeycomb core 12, and the second surface plate 20 to form four side walls of a rectangular parallelepiped. Next, the four end portions of the first face plate 16 of the remaining one soundproof structure 10 are the side surfaces of the four soundproof structure 10 that constitute the four sides of the rectangular parallelepiped shown in FIG. A soundproof box which constitutes, for example, a ceiling portion and constitutes five side walls of a rectangular parallelepiped by bonding and fixing the sound absorber 22, the honeycomb core 12, and each side end of the second surface plate 20). 30 can be configured.
In addition, although it is preferable to perform fixation of sound-insulation structure 10 comrades using an adhesive agent similarly to fixation of the honeycomb core 12 and the 2nd surface board 20 etc., it is a method of using a physical fixing tool. It is good and any fixing method may be used.

As described above, by arranging the soundproof box 30 having five rectangular parallelepiped walls to cover the noise source, a high soundproof effect can be obtained. For example, the soundproof box 30 can be used as a soundproof box for pets such as a kennel, a soundproof box for a device (generator, PC) as a noise source, or a soundproof room for people. When the noise source is suctioned and discharged, the soundproof structure 10 on any surface of the soundproof box 30 may be provided with an opening for suction and an opening for exhaustion although not shown. That is, it is preferable that a ventilating port for intake and exhaust be disposed in the soundproof box. The reason is that the use of a soundproof box having a sound absorbing structure reduces the sound leaked from the ventilating port and has an effect of enhancing the function as a soundproof box with a ventilating opening.
In addition, although the soundproof box 30 mentioned above used the soundproof structure 10 of this invention for the wall of 5 surfaces of a rectangular parallelepiped, this invention is not limited to this, The soundproof structure 10 is used for the walls of 6 surfaces of a rectangular parallelepiped Alternatively, one or more openings (not shown) may be provided in the soundproof structure 10 as an entrance on the wall of one side. Also in this case, in addition to the port, an opening (not shown) for intake and exhaust may be provided.
Further, when the sound absorbing body 22 of the soundproof structure 10 is made of one having a deodorizing effect, it is preferable because the soundproof box 30 can be used for a pet cabin or the like. Further, by arranging a handle (not shown) on the soundproof box 30, it functions as a portable soundproof box, for example, a pet gauge or the like, which is preferable.

Although the soundproof box 30 described above has a rectangular parallelepiped shape, the present invention is not limited to this, and as long as it has a box shape, it may have a cubic shape or any other hexahedron shape. In addition, it may be a polyhedron shape such as a tetrahedron shape, a pentahedron shape, or an octahedron shape.
Further, the example described above is configured using the soundproof structure of the first embodiment of the present invention on the entire wall of the soundproof box of the second embodiment of the present invention or the entire surface wall except one surface. However, the present invention is not limited thereto, and if the soundproof structure of the present invention is used for at least one side wall, the wall of the remaining face has any structure, for example, the soundproof structure of a comparative example described later. You may use.
Not only the entire surface is covered like a box, but one surface may be open, or it may be a partition like one or two pieces.

[Soundproof Enclosure]
Furthermore, the present invention is not limited to the use of the soundproof structure of the first embodiment to form the soundproof box of the second embodiment, and a soundproof enclosure using two or more of the soundproof structures of the first embodiment. The structure may be configured.
When the four soundproof structures 10 are used, the soundproof enclosure structure of the present invention is the same as the cross section of the soundproof box 30 shown in FIG. 7 except that the soundproof structure 10 of the ceiling portion of the soundproof box 30 is removed. It is the structure which consists of the wall of the face. Note that a five or more soundproof structure 10 may be used to form a closed soundproof surrounding structure.
In addition, a soundproof enclosure using two soundproof structures 10 and a soundproof enclosure using three or more soundproof structures 10 are used as a partition surrounding a noise source with the first surface plate 16 side facing the noise source It can also be done.
Such a soundproof surrounding structure can raise a high soundproofing effect by arranging so as to surround a noise source.
The soundproof box and the soundproof surrounding structure of the second embodiment of the present invention are basically configured as described above.

Hereinafter, the present invention will be described in more detail based on examples. Materials, amounts used, proportions, treatment contents, treatment procedures and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Accordingly, the scope of the present invention should not be construed as limited by the following examples.

Example 1
The soundproof structure 10 shown in FIG. 1 was used. In the soundproof structure 10 used, a surface of the paper having a thickness of 30 mm and a width of 12 mm of the honeycomb cell 12 (made by core pack Nishikawa) is made of paper having a thickness of 1 mm without open holes. The face plate 20 (made by Corepack Nishikawa) was adhesively fixed. Further, on the other side, an aluminum micro through hole plate 26 having a micro through hole 24 which is a sound absorbing body 22 is bonded and fixed, and a through hole 18 is further opened with a thickness of 1.0 mm. A paper first front plate 16 is adhesively fixed. The diameter of the fine through holes 24 was 25 μm, the aperture ratio of the fine through holes 24 was 5%, and the thickness of the fine through hole plate 26 was 20 μm. The adhesive used for adhesive fixing was Spray Paste 77 (manufactured by 3M).
In the first surface plate 16 in which the through holes 18 are opened, the through holes 18 having a diameter of 2 mm were opened at a distance 4 mm between the hole centers. The opening ratio of the through hole 18 was 23%. Here, the hole area of the through hole 18 on the honeycomb cross-sectional area (125 mm ² ) of the opening 14 of the honeycomb core 12 is about 28 mm ² . The hole area is about 28 mm ² because the plurality of through holes 18 are distributed on the opening 14 of the honeycomb core 12 and their relative positions are shifted depending on the place.

(Comparative Examples 1 to 3)
The soundproof structure of Comparative Examples 1 to 3 is shown in FIG. 9 to FIG.
As shown in FIG. 9, the soundproof structure 32 of Comparative Example 1 is one in which the honeycomb core 12 made of the above-mentioned cardboard is sandwiched from both sides by the second surface plate 20 made of paper without through holes.
As shown in FIG. 10, the soundproof structure 34 of the comparative example 2 has the sound absorbing urethane 27 having a thickness of 15 mm disposed on the second surface plate 20 on one side of the soundproof structure 32 of the comparative example 1. .
The soundproof structure 36 of Comparative Example 3 has a 12 mm diameter through hole 18 of 1 mm in diameter with a laser beam machine (GCC LaserPro C1802) in the second surface plate 20 on one side of the soundproof structure 32 of Comparative Example 1, as shown in FIG. The first face plate 16 is made of paper with the through holes 18 opened. The opening ratio of the through holes 18 was 0.6%.

FIG. 12 shows the normal incidence sound absorption coefficient of each soundproof structure as measured using a self-made acoustic tube.
Measurement of acoustic characteristics using a self-made acoustic tube was a measurement by a transfer function method using four microphones in a self-made acrylic acoustic tube. This method is in accordance with "ASTM E2611-09: Standard Test Method for Measurement of Normal Incidence Sound Transmission of Acoustical Materials Based on the Transfer Matrix Method". As the acoustic tube, for example, one having the same measurement principle as WinZac manufactured by Nittobo Acoustic Engineering Co., Ltd. was used. Sound transmission losses can be measured in a wide spectral band in this way. The soundproof structure 10 of the present embodiment was disposed at the measurement site of the acoustic pipe, and the measurement of the normal incidence sound absorption coefficient of each soundproof structure was performed in the range of 100 Hz to 4000 Hz. The inner diameter of the acoustic tube is 40 mm and can be sufficiently measured up to 4000 Hz or more.
In Comparative Example 1, the sound absorption coefficient is very low in the measurement frequency range because there is no sound absorption structure. On the other hand, Comparative Example 2 in which the sound absorbing urethane 27 is disposed thereon shows a high sound absorbing effect in the high frequency region. Conversely, in Comparative Example 3, a sound absorption peak is present on the low frequency side, and the sound absorption band is narrow. In Comparative Example 3, since the Helmholtz resonance in the holes of the surface paper and the closed space of the honeycomb core portion is strong due to the small aperture ratio, the sound absorption characteristics in the low frequency narrow band are shown.
On the other hand, it can be seen that the embodiment of Example 1 exhibits a wide and high sound absorption effect from low frequency to high frequency.

(Example 11, Comparative Examples 11 to 13)
Using the soundproof structure 10 of Example 1 and the soundproof structures 32 to 36 of Comparative Examples 1 to 3, the soundproof box 30 of Example 11 and the soundproof boxes of Comparative Examples 11 to 13 each having five walls are manufactured. did.
That is, five walls of 50 cm × 50 cm of each soundproof structure were fixed with an adhesive to produce each soundproof box.
The relationship between Example 11 and Comparative Examples 11 to 13 and Example 1 and Comparative Examples 1 to 3 and their sound absorbing structures are shown in Table 1.

The soundproofing effects of the soundproof box 30 of Example 11 and the soundproof boxes of Comparative Examples 11 to 13 thus produced were measured. The measurement system 40 is shown in FIG.
A speaker 44 for emitting a sound source was disposed inside a soundproof box 42 to be measured. Outside the three microphones 46 and the soundproof box 42 inside the soundproof wall of the soundproof box 42, the microphone 48 was placed 50 cm from the soundproof box 42 at a height of 70 m, and the sound from inside and outside the box from the speaker 44 was measured.
The noise levels (average noise level) of the three microphones 46 inside the soundproof box 42 when pink noise is emitted from the speakers 44 are shown in FIG.
It can be seen that the amount of noise inside the box is the largest when there is no sound absorbing body of Comparative Example 11, and the amount of noise is the smallest when the sound absorbing structure of Example 11 is used.

In the case of the soundproof box 30 of Example 11 and the soundproof box of Comparative Examples 12 to 13 in which the sound absorbing structures for the soundproof box of Comparative Example 11 are arranged when the sound pressure levels of the three microphones 46 are averaged in FIG. Indicates the difference in microphone sound pressure.
In Comparative Example 12, since the sound absorbing structure of Comparative Example 2 is used, a high muffling effect is shown at a high frequency than in Comparative Example 13 and Example 11.
In Comparative Example 13, since the sound absorbing structure of Comparative Example 3 is used, the noise reduction effect higher than that of Comparative Example 12 and Example 11 is shown at low frequency of 315 Hz.
On the other hand, it is considered that the lowest noise amount was obtained because Example 11 exhibited a wide and high muffling effect in the middle frequency band.
By forming the soundproof box 30 using the soundproof structure 10 of the first embodiment, it is possible to greatly reduce the amount of internal noise. In Example 11, although the soundproof box 30 is formed of the soundproof structure 10 of Example 1, the same effect can be obtained even if the soundproof structure 10 of Example 1 is disposed on the wall of a room.

The noise level measured by the microphone 48 outside the soundproof box 42 is shown in FIG.
Outside the soundproof box 42, the soundproof box of Example 11 using the soundproof structure 10 of Example 1 similarly exhibits the lowest noise level.
FIG. 17 shows differences in microphone sound pressure in the case of the soundproof box 30 of Example 11 in which the respective soundproofing structures are arranged with respect to the soundproof box of Comparative Example 11 and the soundproof box of Comparative Examples 12-13.
Since the eleventh embodiment has a broad noise reduction effect in the middle frequency band, it is considered that the suppression effect of the noise leaking out is the highest.

(Examples 21 to 23, Comparative Examples 21 to 22)
In the soundproof structure of Examples 21 to 23, as shown in FIG. 1, one honeycomb cell is 12 mm in width and 30 mm in thickness on a paper-made second surface plate 20 (made by Core Pack Nishikawa) having a thickness of 1 mm. A paper-made honeycomb core 12 (made by Corepack Nishikawa) was adhesively fixed. On this honeycomb core 12, an acrylic plate having a thickness of 1 mm as the first surface plate 16 was disposed in a state in which the through holes 18 having the diameter and the aperture ratio as shown in Table 2 were opened. As a sound absorber 22 between the acrylic plate (first surface plate 16) having the through holes 18 and the honeycomb core 12, fine through holes 24 with a diameter of 25 μm are opened at an aperture ratio of 6.2% in an aluminum foil with a thickness of 20 μm. A film-like fine through hole plate 26 was used.
An adhesive was fixed between the acrylic plate (first surface plate 16) and the aluminum foil (fine through hole plate 26), and between the aluminum foil (fine through hole plate 26) and the honeycomb core 12. The same adhesive as used in Example 1 was used for adhesive fixing.
As Comparative Example 21, a soundproof structure 36 as shown in FIG. 11 in which the sound absorber 22 is removed from Example 21 and in which the through holes 18 having the diameter and the aperture ratio as shown in Table 2 are open Made.
As Comparative Example 22, a soundproof structure having the same soundproof structure as in Example 21 and having through holes 18 having diameters and aperture ratios as shown in Table 2 was manufactured.

FIG. 18 shows the normal incidence sound absorption coefficients of Examples 21 to 23 and Comparative Examples 21 to 22 measured with an acoustic tube in the same manner as in Example 1 described above.
First, in Comparative Example 21, due to the high air frictional resistance at the side wall of the small through hole 18 (see FIG. 11) having an aperture ratio of less than 1%, 1.0 mm, a sound absorber is not disposed but a high sound absorption coefficient is 690 Hz. It is shown at the resonance frequency. However, the band showing a high sound absorption coefficient is narrow.
In this configuration, in Comparative Example 22 in which a sound absorber is arranged, the sound absorption coefficient of the sound absorption peak at the resonance frequency is lowered. This is because the resistance of the sound absorber is further added to the air resistance of the small through hole 18 having an aperture ratio of less than 1% and 1.0 mm. Therefore, in the configuration of the first surface plate 16 of the soundproof structure according to the present invention, the aperture ratio of the through holes 18 needs to be 1.0% or more, and the diameter is preferably 1.0 mm or more.
Further, it is understood from the results of Examples 21 to 23 in FIG. 18 that as the diameter of the through hole 18 is increased and the aperture ratio of the through hole 18 is increased, the sound absorption center frequency is increased and the band is expanded.

FIG. 19 shows the result of the noise level in which 200 to 4000 Hz is added by multiplying the pink noise by the transmittance (1−sound absorption coefficient) obtained from the normal incidence sound absorption coefficient shown in FIG. From this result, it is understood that the noise level decreases as the aperture ratio increases, as in the calculation result shown in FIG. 6A. Also, it can be seen that the noise level drops sharply at an aperture ratio of 5%, further drops at 10%, and the slope decreases at 20% or more.
Although membrane-like fine through hole plates are used in the twenty-first to twenty-third embodiments, as long as fine holes are formed in the same manner, a net-like structure or a non-woven fabric may be used.
Moreover, when these sound absorbers consist of metals, since nonflammability increases, it is preferable.

In addition, since a sound absorbing body having such an open fine through hole can obtain a high sound absorbing effect even in a thin state, it is preferable because a high sound absorbing performance can be obtained without largely increasing the thickness of the soundproof structure.
In particular, in the case of constructing a soundproof box using this soundproof structure, it is possible to suppress a decrease in internal volume, which is preferable.
In the soundproofing structures 21 to 23 of the present embodiment, the sound absorption coefficient is lowered at a high frequency than the air column resonance frequency, but the sound absorption coefficient can be suppressed by arranging the sound absorbing material inside the air column. . As described above, the sound absorbing material may be a woven material, a knitted fabric, a non-woven material, or a porous material such as urethane, or may be a membrane-like fine through hole plate.
The soundproofing structure of the present invention has a broad band and high sound absorbing effect as compared with various other sound absorbing structures.
From the above results, the effects of the present invention are clear.

[Cover layer]
By the way, in the soundproof structure 10 shown in FIG. 1, although nothing is covered on the outer side (upper side in FIG. 1) of the 1st surface board 16, this invention is not limited to this. In the present invention, as in the soundproof structure 11 shown in FIG. 20, the cover layer 23 may be disposed on the outer side (upper side in FIG. 20) of the first surface plate 16.
Similarly to the soundproof structure 10 shown in FIG. 1, the soundproof structure 11 shown in FIG. 20 includes a honeycomb core 12 having a plurality of openings 14, a plate-like first surface plate 16 having a plurality of through holes 18, and a second In addition to the configuration of the soundproof structure 10 shown in FIG. 1 having the face plate 20 and the sound absorbing body 22, it further has a cover layer 23 disposed on the outside (upper side in FIG. 12) of the first face plate 16. is there.
The cover layer 23 is preferably a breathable layer for protection of the sound absorber 22 and a design for covering the through holes 18 of the first surface plate 16. For example, a fine through hole plate, a woven cloth, a knitted fabric, Nonwoven fabric or mesh shape such as polyester double mesh can be used.

In addition, it is preferable that the cover layer 23 is a thing which does not change the sound absorption characteristic of the soundproof structure of this invention.
However, if the acoustic resistance is high, the sound absorption effect is reduced, so the total acoustic resistance of the cover layer 23, the first surface plate 16 and the sound absorber 22 is preferably 10 to 50000 Rayl, more preferably 50 to 10000 Rayl, and 100 to 2000 Rayl. Is more preferred.
In order to obtain this acoustic resistance, the acoustic resistance of the cover layer 23 is preferably 1 to 10000 Rayl, more preferably 5 to 5000 Rayl, and still more preferably 10 to 1000 Rayl.
Further, the total flow resistance of the ventilation flow resistance R1 of the through hole 18 of the first surface plate 16, the ventilation flow resistance R2 of the sound absorber 22 and the ventilation flow resistance R3 of the cover layer 23 is 12 Rayl or more and 16700 Rayl or less Is preferred. The reason is that such total air flow resistance can provide a sound absorption effect of 10% or more at the resonance frequency. The total aeration flow resistance described above is 75 Rayl or more, more preferably 2570 Rayl or less, and more preferably 170 Rayl or more, and most preferably 1150 Rayl or less. A more preferable range of the above total vent flow resistance is a value at which a sound absorption effect of 50% or more is obtained at the resonance frequency, and a most preferable after range of the above total vent flow resistance is 80% or more at the resonance frequency It is a condition under which a sound absorption effect can be obtained.
Further, it is preferable that the ventilation flow resistance R2 of the sound absorber 22 is larger than the ventilation flow resistance R3 of the cover layer 23. The reason is that the cover layer 23 has a high possibility of coming into contact with the object, and the air flow resistance value is easily changed, so that the cover layer 23 does not have the sound absorption control function and the sound absorbing body has a low possibility of contact. It is because the sound absorption effect is stabilized by controlling.
By arranging the cloth cover layer 23 on the first surface plate 16 as in the soundproof structure 11, the plurality of through holes 18 of the first surface plate 16 can be hidden. Further, in the plurality of through holes 18 of the first surface plate 16, the sound absorber 22 is directly exposed to the outside, so by disposing the cover layer 23 on the first surface plate 16, Contact to the sound absorber 22 can be prevented.

A soundproof structure 11 shown in FIG. 20 in which a polyester double mesh is disposed as a cover layer 23 on the soundproof structure 10 (see FIG. 1) of the configuration of Example 1 described above (see FIG. 1) and the first face plate 16 of the soundproof structure 10 of Example 1. The normal incidence sound absorption coefficient of was measured using a self-made acoustic tube. The results are shown in FIG.
As shown in FIG. 21, it can be seen that the sound absorption characteristics hardly change with the presence or absence of the cloth cover layer 23.
In the measurement of the normal incidence sound absorption coefficient of the

soundproof structures

10 and 11 of the configuration of Example 1, when the honeycomb cores 12 of the respective

soundproof structures

10 and 11 have the structure shown in FIG. When the area of is the measurement area 50 of the normal incidence sound absorption coefficient, as shown in FIG. 23, the honeycomb cells of the honeycomb core 12 which were out of the measurement area 50 were filled with clay and measured.
As a result, in the sound absorption spectrum of the soundproof structure 10 of the first embodiment shown in FIG. 12 and the normal incidence sound absorption coefficient of the soundproof structure 10 of the configuration of the first embodiment shown in FIG. I understand that

In the present invention, as in the soundproof structure 10A shown in FIGS. 24 and 25, the first surface plate 16 has a hole diameter smaller than the hole diameter of the through hole 18 in addition to the through hole 18, You may have the small through-hole 19 of the small size which is less than 1.0%. As shown in FIG. 24 and FIG. 25, it is fine between one honeycomb cell of the honeycomb core 12 corresponding to one through hole 18 and the first surface plate 16 in which the through hole 18 is provided. The through hole plate 26 (sound absorber 22) is disposed. However, when one small through hole 19 is provided corresponding to one honeycomb cell of the honeycomb core 12, the fine through hole plate 26 (sound absorber 22) is not disposed, and the small through hole 19 is not provided. The honeycomb cells corresponding to the above form a closed space as the back space of the small through hole 19.

Here, as described above, the through holes 18 of the first face plate 16 do not disturb the air column resonance, that is, do not induce the air column resonance to induce the Helmholtz resonance, and a large hole having an aperture ratio of 1% or more It is. On the other hand, the small through hole 19 is a hole smaller than the hole diameter of the through hole 18 having an aperture ratio of less than 1.0% which induces the Helmholtz resonance and does not induce the air column resonance. Therefore, in the soundproof structure 10A, the small through holes 19 are provided in the portion of the first surface plate 16 corresponding to five honeycomb cells of the seven honeycomb cells of the honeycomb core 12, and the two honeycomb cells are A through hole 18 is provided in the corresponding portion of the first front plate 16.
The soundproof structure 10A of the present invention shown in FIGS. 24 and 25 is a hole of the first surface plate 16 which is a perforated plate, the through hole 18 for increasing the hole diameter to induce air column resonance, and the hole diameter is small Helmholtz Although the structure uses the small through hole 19 for inducing resonance in combination, since the small through hole 19 for inducing Helmholtz resonance is provided, the band that can be muffled is narrow, and the low frequency band can be muffled in a wide band. Have an effect.

(Examples 31 to 32, Comparative Example 31)
Here, the soundproof structure 10A shown in FIGS. 24 and 25 as Example 31 and the soundproof structure 10B shown in FIGS. 26 and 27 as Example 32 and FIGS. 28 and 28 as Comparative Example 31. A soundproof structure 36A shown in 29 was used.
In the soundproof structures 10A to 10B of Examples 31 to 32 and the soundproof structure 36A of Comparative Example 31, as shown in FIGS. 24 to 29, the upper surface of the rigid wall which is the second surface plate 20 made of aluminum and having a thickness of 10 mm. An acrylic honeycomb core 12 having a diagonal width of 14 mm and a thickness of 30 mm was bonded and fixed to one honeycomb cell.

In the soundproof structure 10A of Example 31, as shown in FIGS. 24 and 25, an acrylic plate having a thickness of 2 mm as the first surface plate 16 is formed on the honeycomb core 12 into two upper and lower honeycomb cells in FIG. Correspondingly, a state in which through holes 18 having a diameter of 10 mm and an aperture ratio of 53% are opened at its center, and small penetrations having a diameter of 1 mm and an aperture ratio of 0.4% corresponding to the remaining five honeycomb cells The holes 19 were arranged in the open state. As a sound absorber 22 between the acrylic plate (first surface plate 16) having the through holes 18 and the small through holes 19 and the honeycomb core 12, a minute through hole 24 having a diameter of 25 μm is formed in an aluminum foil having a thickness of 20 μm. A membrane-like fine through hole plate 26A opened at 2% was used. In the minute through hole plate 26A, openings 25 were opened corresponding to the five honeycomb cells in which the small through holes 19 were opened. In FIG. 24, the portion where the small through hole plate 26A exists is shown by hatching.

In the soundproof structure 10B according to the thirty-second embodiment, as shown in FIGS. 26 and 27, in the soundproof structure 10B of the thirty-second embodiment, an acrylic plate having a thickness of 2 mm as the first surface plate 16 is formed on the honeycomb core 12; A through hole 18 having a diameter of 10 mm and an open area ratio of 53% was disposed at the center corresponding to all seven honeycomb cells. As a sound absorber 22 between the acrylic plate (first surface plate 16) having the through holes 18 and the honeycomb core 12, fine through holes 24 with a diameter of 25 μm are opened at an aperture ratio of 6.2% in an aluminum foil with a thickness of 20 μm. A film-like fine through hole plate 26 was used on the entire surface. In FIG. 26, the portion where the fine through hole plate 26 exists is shown by hatching.
Adhesively fixed between acrylic plate (first surface plate 16) and aluminum foil (fine through

hole plate

26 or 26A), and between aluminum foil (fine through

hole plate

26 or 26A) and honeycomb core 12 It was The same adhesive as used in Example 1 was used for adhesive fixing.

In the soundproof structure 36A of Comparative Example 31, as in Comparative Example 21, as shown in FIGS. 28 and 29, on the honeycomb core 12, an acrylic plate having a thickness of 2 mm as the first surface plate 16 is shown in FIG. In a state in which through holes 18 having a diameter of 1 mm and an aperture ratio of 0.4% were opened at the center corresponding to all seven honeycomb cells. The same adhesive as used in Example 1 was used for adhesive fixing.

FIG. 30 shows the normal incidence sound absorption coefficient of Examples 31 to 32 and Comparative Example 31 measured with an acoustic tube in the same manner as Example 1 described above.
First, in Comparative Example 31, although the sound absorber is not disposed due to high air frictional resistance in the side wall of the small through hole 19 (see FIGS. 28 and 29) having an aperture ratio of 0.4% and 1.0 mm. It shows a high sound absorption coefficient at low frequencies. However, it can be seen that the band showing a high sound absorption coefficient is extremely narrow.
On the other hand, in Example 31, since the through holes 18 having a large diameter and the small through holes 19 having a small diameter are mixed in the first surface plate 16, only the through holes 18 having a large diameter are shown in Table 1 As compared with the embodiment 32 in which the face plate 16 is perforated, it is understood that although the sound absorption band becomes narrower, the low frequency band can be muffled in a wide band.
In Example 32, as in Example 1, since the diameter of the through hole 18 is large and the aperture ratio of the through hole 18 is increased, it can be seen that the sound absorption center frequency is high and the band is wide.

(Examples 41 to 42)
In Examples 41 to 42, as in the soundproof structure 10C shown in FIG. 31 and FIG. 32, the width of one honeycomb cell is 12 mm on the second surface plate 20 (made by Core Pack Nishikawa) made of paper and 1 mm thick. A paper honeycomb core 12 (made by Core Pack Nishikawa) having a thickness of 30 mm was adhesively fixed. Kraft paper having a thickness of 1 mm as the first surface plate 16 is formed on the honeycomb core 12 in a state in which through holes 18 having a hole pattern: square holes, a diameter of 1 mm, a distance between hole centers of 5.5 mm and an aperture ratio of 23% It was arranged. A non-woven fabric (Example 41) and a woven cloth (Example 42) were used as the sound absorber 22 between the honeycomb core 12 and the perforated paper (first surface plate 16) made of kraft paper having the through holes 18 .

In Example 41, as a non-woven fabric, the surface of a micromat (product name, manufactured by Softpren Industrial Co., Ltd.) was peeled off and used in a state of 1 mm or less in thickness.
In Example 42, a color broad of 1 mm or less was used as a woven cloth.
The kraft paper (first face plate 16) and the sound absorbing material 22 (nonwoven fabric, woven fabric), and the sound absorbing material 22 (nonwoven fabric, woven fabric) and the honeycomb core 12 are adhesively fixed. The same adhesive as used in Example 1 was used for adhesive fixing.
FIGS. 33 and 34 show the normal incidence sound absorption coefficients of the examples 41 and 42 measured with an acoustic tube in the same manner as the above-mentioned example 1, respectively.
As shown in FIGS. 33 and 34, even when the nonwoven fabric of Example 41 and the woven cloth of Example 42 are used as the sound absorber 22, it is understood that the sound absorption center frequency is high and the band is wide.

(Examples 51 to 52)
Examples 51 to 52 have the same configuration as those of Examples 41 and 42 which are the soundproof structure 10C shown in FIGS. 31 and 32, and the sound absorber 22 has a thickness of 20 μm instead of non-woven fabric and woven fabric. The difference is that the film-like fine through hole plate 26 in which the fine through holes 24 with a diameter of 25 μm are opened at an aperture ratio of 6.2% is used in the aluminum foil. Here, when the through holes 18 are punched in the first surface plate 16 by kraft paper (perforated paper), the holes do not become completely straight, and as shown in FIG. 35 or 36, the honeycomb core 12 is formed. The diameter of the hole on the side (the fine through hole plate 26A side) is different from the diameter of the hole on the opposite side (the surface in contact with air).
In Example 51, as shown in FIG. 35, the hole shape of the through hole 18A (18) of kraft paper which is the first surface plate 16 has a hole diameter on the honeycomb core 12 smaller than the hole diameter on the opposite side. It was a shape, that is, a downward convex shape.
On the other hand, contrary to Example 51, in Example 52, the hole shape of the through hole 18B (18) of the kraft paper which is the first surface plate 16 is the honeycomb core 12 side as shown in FIG. The hole diameter was larger than the opposite hole diameter, i.e., convex upward.

FIG. 37 shows the normal incidence sound absorption coefficient of each of Examples 51 and 52 measured with an acoustic tube in the same manner as in Example 1 described above.
As shown in FIG. 37, Example 51 having a through hole 18A having a convex hole shape downward exhibits a higher sound absorption coefficient than Example 52 having a through hole 18B having a convex hole shape downward, It can be seen that the sound absorption characteristics are good.
By the way, when the through hole 18 is punched in the first surface plate 16 by burring, burrs are generated at the edge of the hole having the smaller diameter. When the sound absorbing body 22 is attached to the surface of the first front plate 16 having the burrs, the burrs do not adhere well because the burrs are present. Therefore, in the case where the first front plate 16 and the sound absorbing body 22 are attached, a protrusion such as a burr around the hole on the edge of the hole on the opposite surface (the surface in contact with air) of the sound absorbing body 22 It is preferable to have That is, as shown in FIG. 36, the sound absorption characteristics shown in FIG. 37 are worse when the sound absorber 22 is attached to the surface of the first surface plate 16 having the larger diameter of the through holes 18B than in the reverse case. When there is a burr on the surface of the first surface plate 16 on the opposite side of the sound absorber 22 (the surface that touches the air), the manufacturing suitability is excellent. Therefore, when priority is given to manufacturing characteristics, the structure shown in FIG. 36 may be employed.

As mentioned above, although various embodiments and examples about a soundproofing structure, a soundproofing surrounding structure, and a soundproofing box concerning the present invention were mentioned in detail and were explained, the present invention is not limited to these embodiments and examples, Of course, various improvements or modifications may be made without departing from the spirit of the present invention.

The soundproof structure according to the present invention is, for example, inside or outside of a building or other structure (for example, a wall, ceiling panel, etc. for housing, hall, elevator, music classroom, meeting room, etc.), animal (for example, , Pet), and transportation applications such as interiors of automobiles, and logistics applications such as box materials and packing materials.

10, 10A, 10B, 10C, 11, 32, 34, 36, 36A, 38 soundproof structure 12

honeycomb core

14, 25 opening 16

first surface plate

18, 18A, 18B through hole 19 small through hole 20 second surface plate 22 Sound absorber 23 Cover layer 24 fine through

holes

26, 26A fine through hole plate 27 sound absorbing urethane 28

Helmholtz resonance structure

30, 42 soundproof box 40 measurement system 44

speaker

46, 48 microphone 50 measurement area

Claims

With a honeycomb core,
A first face plate sandwiching the honeycomb core, and a second face plate;
A through hole bored in the first surface plate;
A sound absorber disposed on one surface of the first surface plate located on the side of the honeycomb core,
The soundproof structure whose aperture ratio of the said through-hole in a said 1st surface board is 1.0% or more.
The diameter of the through hole is 1.0 mm or more,
The soundproof structure according to claim 1, wherein an opening area of the through hole of the first surface plate is smaller than an opening area of the honeycomb core.
The honeycomb cells of the honeycomb core sandwiched by the first surface plate and the second surface plate are hollow,
The soundproof structure according to claim 1 or 2, wherein when the thickness of the honeycomb core is l, the thickness of the first surface plate is h, and the aperture ratio is ar, the condition of the following inequality (1) is satisfied.
f 1 (l, h) × ln (ar) + f 2 (l, h) ≧ 1 (1)
Here, f 1 (l, h) = A 1 (h) × l 2 + A 2 (h) × l + 0.24915
f 2 (l, h) = A 3 (h) × l 2 + A 4 (h) × l + 1.804
A 1 (h) = 19.466 × ln (h) -0.3038
A 2 (h) = − 1.611 × ln (h) +4.0162
A 3 (h) = 119.22 × ln (h) +78.249
A 4 (h) =-5689.7 × h + 94.861
The soundproof structure according to any one of claims 1 to 3, wherein the honeycomb core is made of paper, metal or resin.
The soundproof structure according to any one of claims 1 to 4, wherein the first front plate is made of paper, metal or resin.
The soundproof structure according to any one of claims 1 to 5, wherein the second front plate is made of paper, metal or resin.
The soundproof structure according to any one of claims 1 to 6, wherein the sound absorber comprises a fine through hole plate, a woven cloth, a knit, or a non-woven fabric.
The soundproof structure according to any one of claims 1 to 7, wherein the sound absorber penetrates in the thickness direction and has a plurality of fine through holes with a diameter of 1 μm to 250 μm.
The sound absorber has a plurality of fine through holes penetrating in the thickness direction,
The average diameter of the fine through holes is 0.1 μm or more and less than 100 μm,
When the average diameter of the fine through holes is phi (μm) and the thickness of the sound absorber is t (μm), the average aperture ratio rho of the fine through holes is in the range of more than 0 and less than 1. rho_center = (2 + 0.25 × t) × phi−1.6 is the center, rho_center− (0.052 × (phi / 30) −2) is the lower limit, and rho_center + (0.795 × (phi / 30) −2) is the upper limit A soundproofing structure according to any one of the preceding claims which is in the range.
The soundproof structure according to any one of claims 1 to 9, wherein the material of the sound absorber is a flame retardant material.
The soundproof structure according to claim 10, wherein the flame retardant material is metal.
The soundproof structure according to claim 11, wherein the metal is aluminum or an aluminum alloy.
The soundproof structure according to any one of claims 1 to 12, wherein a thickness of the sound absorber is 50 mm or less.
The soundproof structure according to any one of claims 1 to 13, wherein aeration flow resistance of the sound absorber is 10 to 50000 Rayl.
The air flow resistance of the sum of the air flow resistance R1 of the portion of the through hole of the first surface plate and the air flow resistance R2 of the sound absorber is 12 Rayl or more and 16700 Rayl or less. Soundproof construction as described in Section.
And a cover layer disposed on the side of the first face plate opposite to the sound absorber,
The total flow resistance between the through flow resistance R1 of the through hole of the first front plate and the through flow resistance R2 of the sound absorber and the through flow resistance R3 of the cover layer is 12 Rayl or more and 16700 Rayl or less. The soundproof structure according to any one of Items 1 to 14.
The soundproof structure according to claim 16, wherein the flow resistance R2 of the sound absorbing body is larger than the flow resistance R3 of the cover layer.
The soundproof structure according to claim 16 or 17, wherein the cover layer is made of a fine through hole plate, a woven cloth or a non-woven fabric.
The soundproof structure according to any one of claims 1 to 18, wherein the through holes having two or more different hole diameters are opened in the first surface plate.
The soundproof structure according to any one of claims 1 to 19, wherein the first surface plate further has a small through hole having a hole diameter smaller than the hole diameter of the through hole and having an opening ratio of less than 1.0%. .
The soundproof structure according to any one of claims 1 to 20, wherein the sound absorber has a deodorizing function.
The soundproof structure according to any one of claims 1 to 21, further comprising an air-permeable cover layer disposed on one surface of the first face plate opposite to the honeycomb core side.
A soundproof surrounding structure using two or more of the soundproofing structures according to any one of claims 1 to 22.
A soundproof box having the soundproof surrounding structure according to claim 23.
A soundproof box comprising the soundproof structure according to any one of claims 1 to 22.
The soundproof box according to claim 24 or 25, wherein a vent for air intake and exhaust is arranged.