JP3601575B2 - Sound absorbing structure - Google Patents
Sound absorbing structure Download PDFInfo
- Publication number
- JP3601575B2 JP3601575B2 JP10838198A JP10838198A JP3601575B2 JP 3601575 B2 JP3601575 B2 JP 3601575B2 JP 10838198 A JP10838198 A JP 10838198A JP 10838198 A JP10838198 A JP 10838198A JP 3601575 B2 JP3601575 B2 JP 3601575B2
- Authority
- JP
- Japan
- Prior art keywords
- sound absorbing
- thickness
- sound
- absorption coefficient
- air layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000011491 glass wool Substances 0.000 claims description 34
- 239000011358 absorbing material Substances 0.000 claims description 28
- 239000002985 plastic film Substances 0.000 claims description 4
- 229920006255 plastic film Polymers 0.000 claims description 4
- 239000010410 layer Substances 0.000 description 58
- 238000010521 absorption reaction Methods 0.000 description 43
- 238000010586 diagram Methods 0.000 description 12
- 230000005484 gravity Effects 0.000 description 9
- 230000001681 protective effect Effects 0.000 description 6
- 239000000463 material Substances 0.000 description 4
- 239000011490 mineral wool Substances 0.000 description 4
- 239000004745 nonwoven fabric Substances 0.000 description 4
- 238000009434 installation Methods 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 229920002620 polyvinyl fluoride Polymers 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 238000013016 damping Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- -1 perforated plate Substances 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000004078 waterproofing Methods 0.000 description 1
Images
Landscapes
- Laminated Bodies (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
- Building Environments (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、道路交通騒音を軽減するための吸音構造体、例えば高架橋裏面吸音板として好適な吸音構造体に関する。
【０００２】
【従来の技術】
道路交通騒音に対する対策が重要になってきており様々な対策がなされるようになってきた。例えば道路と住宅地との間に高さ５ｍ程の防音壁を建てたり、騒音の発生を低減できる排水性舗装などが施されている。さらに、高架橋道路と併設されている道路では、地上を走行する車からの騒音が高架橋裏面に反射して住宅地に騒音を及ぼすため、高架橋の裏面に吸音板を配して騒音を低減している。また、半地下式の割堀道路やトンネル道路でも開口部からの騒音が沿道住宅地に影響を及ぼすことになるため、割堀道路壁面やトンネル壁面に吸音板を配することにより騒音を低減している。
【０００３】
道路交通騒音に用いられる吸音構造体は、特許関係ではこれまで特開平１０−２５７１３号公報、特開平９−３１６８３１号公報、特開平９−１１１９１０号公報、特開平７−９０８１６号公報等が開示されている。
これら種々の吸音構造体の中で、枠体、グラスウール等の繊維質吸音材、繊維の飛散防止・防水のため繊維質吸音材を覆う保護フィルム及びその前面を保護する多孔板から構成される吸音構造体は一般的によく用いられるものであって安価である。さらに、広い周波数帯域に対して有効に吸音率を上げるために、かさ比重の異なる吸音材を積層構造にすれば効果的であることも知られている。
【０００４】
【発明が解決しようとする課題】
道路交通騒音に用いられる吸音構造体は広い周波数帯域にわたって非常に高い吸音率が要求され、設置場所に応じて吸音率の基準値が設けられている。従来は吸音構造体を適用する設置場所毎に前記の構成要素を適当に組み合わせ、その中から当該設置場所に適用される基準値を満たす構造を見いだしている。しかし、この場合、見いだした吸音構造体の構造が最適なものであるかどうかは分からない。すなわち、その吸音構造体と同一厚さでさらに吸音性能の優れた構造があるかも知れず、あるいは、その吸音構造体と同一吸音性能であればさらに厚さを薄くできる構造があるかも知れない。
【０００５】
本発明は、コストや建築限界の制約から、できるだけ薄くて吸音性能のよい吸音構造体が望まれている現状に鑑み、道路交通騒音に対して効率的に吸音率を向上させることができる具体的な吸音構成を見いだし、優れた吸音率を有する吸音構造体を得ることを目的とする。
【０００６】
【課題を解決するための手段】
本発明による吸音構造体は、枠体の前面に配置された多孔板と、枠体の中に配置された繊維質吸音材を有する吸音構造体において、繊維質吸音材が平らで厚さが５０〜１１０ｍｍであり、かつプラスチックフィルムに覆われ、さらに多孔板と繊維質吸音材の間に厚さ１０ｍｍ〜３０ｍｍの空気層が設けられていることを特徴とする。この場合、さらに繊維質吸音材と枠体の背面板の間に空気層が設けられ、その空気層の厚さが３０ｍｍ以下のとき、高い吸音率が得られる。
また、上記の吸音構造体において、それぞれプラスチックフィルムに覆われた繊維質吸音材が前後２層積層され、その合計厚さが５０〜１１０ｍｍであるのが望ましく、その場合、第１層（前面側）の繊維質吸音材の厚さを２５ｍｍ以上とするとき吸音率が特に高い。また、この場合において、前後２層の繊維質吸音材がいずれもグラスウールのとき、そのかさ密度が後述する図７のａ〜ｈで囲まれた領域にあることが望ましい。
【０００７】
【発明の実施の形態】
以下、図１〜図１３を参照して、本発明をより具体的に説明する。
まず、図１に示すのは、本発明に係る吸音構造体の一例（長手方向に垂直な断面）であり、例えば高架橋の桁下に下向きに吊り下げられかつ複数個互いに連結して取り付けられる吸音構造体である。
この吸音構造体は、枠体１と多孔板２から構成される中空枠体と、その内部に配置された繊維質吸音材３、４からなる。枠体１はアルミ押出形材等からなり繊維質吸音材３、４の背面と側面を被い、両側縁部にこの吸音構造体同士を相互に隙間なく連結するための連結部５、６が設けられている。多孔板２は適宜開口率をもつエキスパンドメタル又はパンチングメタル等からなるもので、枠体１に接続され、かつ繊維質吸音材３、４の前面及び側面を被っている。
なお、枠体、多孔板等はアルミのほか、鉄板、ステンレス鋼板等をもちいてもよい。また、これらは押出材のほか圧延材からも製作でき、枠体と多孔板を押出形材で一体成形することもできる。
【０００８】
繊維質吸音材３、４は例えばグラスウール、ロックウール、不織布等の繊維質吸音材の層であり、例えばポリフッ化ビニル等のフィルムで被覆され、積層されている。枠体１の中央部には吊り下げ用の凹溝７が長手方向に形成されており、ここに図示しない吊りボルトのヘッドが嵌入し、この吸音構造体を吊り下げるようになっている。また、８は吸音材３、４を保護するため多孔板２の内面に沿って適宜設けられるグラスクロス等の保護材、９は表面空気層、１０は背後空気層を構成する隙間である。
なお、この図１には記載していないが、特開平９−１１１９１０号公報に記載されたように、例えば枠体の内側に瀝青系樹脂、ゴム系樹脂等の制振材を張り付けるなどして設けてもよい。
【０００９】
続いて、図２〜図１３により、本発明に係る吸音構造体が優れた吸音率を示すことを説明する。
本発明では、吸音構造体の吸音率を伝達マトリックス法で求めた。これは、吸音構造体の各構成要素（グラスウール１層の場合、音の入射側から順に多孔板、空気層、保護フィルム、グラスウール、保護フィルム、空気層）ごとに伝達マトリックスを作り、これらを結合して吸音構造体の伝達マトリックスを作り、終端（枠体の背面板）剛壁の条件で表面（多孔板外側表面）のインピーダンスＺを算出するというものである。このとき、多孔板の開口率：６０％、板厚：２ｍｍ、孔径：８ｍｍとし、保護フィルムはポリフッ化ビニルフィルム（厚さ：１２μｍ、面密度：２０ｇ／ｍ２）とし、グラスウール中の音速及び実効密度は図１３にポイントで示す周波数毎に音響管を用いて測定を行って、表面インピーダンスＺを求めた。次式（１）によって、吸音構造体の垂直入射吸音率αｉが周波数毎に算出できる。なお、この方法で求めた垂直入射吸音率は、実際に測定した吸音構造体の垂直入射吸音率とほぼ一致することが、本発明者らにより確かめられている。
【数１】
さらに、図１３に示す道路交通騒音の加重値Ｌｉと周波数の関係から、次式（２）に基づいて、道路交通騒音重み付け吸音率α（道路交通騒音の周波数特性による重み付け平均値）を計算する。
【数２】
図２〜図４は、表面空気層（枠体とグラスウールの間の空気層）と背後空気層（グラスウールと枠体の背面板の間の空気層）をそれぞれ０ｍｍ、１０ｍｍ、２０ｍｍとしたときの、グラスウール厚さ（一層のみ）と道路交通騒音重み付け吸音率との関係を示した図である。図中、ＧＷ２４Ｋ〜ＧＷ６４Ｋとあるのは、市販のグラスウールのかさ比重（２４Ｋｇ／ｍ２〜６４Ｋｇ／ｍ２）を示す。図２〜図４に示すように、グラスウールのかさ比重が違っても、吸音率は厚さが５０ｍｍ辺りから大きくなり、１００ｍｍを越えても吸音率の上昇がそれほど期待できない。従って、グラスウール層は５０〜１１０ｍｍ、好ましくは７５〜１００ｍｍの範囲とすればよい。また、表面及び背後空気層がない場合は、空気層がある場合に比べ全体に吸音率が低い。
なお、この例では、グラスウール層は１層であったが、これを多層とした場合や、他の繊維質吸音材（ロックウール、不織布等）を用いた場合でもほぼ同様の傾向を示し、トータル厚さが５０〜１１０ｍｍ、好ましくは７５〜１００ｍｍで高い吸音率が効率的に得られる。また、多孔板の開口率や保護フィルムの厚さ（ポリフッ化ビニルフィルムには例えば２１μｍ厚等がある）が変化しても、吸音率はほぼ同様の傾向を示し、前記の数値範囲内で優れた吸音率を示す（この点については、後述する図５〜図１２でも同じことがいえる）。
【００１２】
図５〜図６は、表面空気層及び背後空気層をそれぞれ２０ｍｍとし、グラスウールを前後２層積層し、第１層グラスウール及び第２層のグラスウール厚さをそれぞれ３７．５ｍｍ（トータル７５ｍｍ）又は５０ｍｍ（トータル１００ｍｍ）としたときの、第１層と第２層のグラスウールそれぞれのかさ比重と道路交通騒音重み付け吸音率との関係を示す。図中、吸音率を０．０１刻みの等高線で示している。図７はその中から高い吸音率が得られる範囲を抜きだして示すもので、だいたい図中のａ〜ｈで囲まれた範囲（太線内）で吸音率が高く、さらにａ〜ｂ、ｉ、ｊ、ｆ〜ｈで囲まれた範囲（左下がりの斜線内）でさらに吸音率が高く、ｉ、ｋ、ｌ、ｊのラインとｂ、ｋ、ｌ、ｇで囲まれた範囲（右下がりの斜線内）でさらに優れた吸音率を示す。なお、ａ〜ｈはそれぞれ横軸の１６Ｋ〜６４Ｋのラインと縦軸の１６Ｋ〜８０Ｋのラインの各交点を示す。
【００１３】
図８〜図９は、第１層グラスウールのかさ密度を３２ｋｇ／ｍ３とし、第２層グラスウールのかさ密度を４８ｋｇ／ｍ３又は６４ｋｇ／ｍ３とし、表面空気層及び背後空気層をともに２０ｍｍとしたときの、それぞれのグラスウール厚さと道路交通騒音重み付け吸音率との関係を示す。図中、吸音率を０．００５刻みの等高線で示している。図１０はその中から高い吸音率が得られる範囲を抜きだして示すもので、第１層の厚さをＸ、第２層の厚さをＹとしたとき、だいたいＸ＋Ｙ≧５０の範囲で吸音率が急に高くなり、Ｘ＋Ｙ≧１１０を越えても吸音率の改善は小さい。特にＸ≧３０の範囲で、さらにＸ≧５０、Ｘ＋Ｙ≦１００の範囲で高い吸音率が効率的に得られる。
なお、この例では、２層ともグラスウール層であったが、他の繊維質吸音材（ロックウール、不織布等）を用いた場合でもほぼ同様の傾向を示す。また、表面及び背後空気層の厚さが変化してもほぼ同様の傾向を示す。
【００１４】
図１１〜図１２は、第１層グラスウールのかさ比重を３２Ｋ、第２層グラスウールのかさ比重を４８Ｋ、第１層の厚さを２５ｍｍ又は５０ｍｍ、第２層の厚さを２５ｍｍとしたときの、表面空気層及び背後空気層と道路交通騒音重み付け吸音率との関係を示す。図中、吸音率を０．００５刻みの等高線で示している。表面空気層及び背後空気層は、吸音構造体の厚さを薄くする意味ではできるだけ薄くする方が良いが、効率よく吸音率を向上させるためには、表面空気層を１０ｍｍ〜３０ｍｍとすることが望ましい。背後空気層は３０ｍｍ以下にすればよい。なお、この例では、２層ともグラスウール層であったが、これが一層でも、グラスウールのかさ比重を変えた場合でも、あるいは他の繊維質吸音材（ロックウール、不織布等）を用いた場合でもほぼ同様の傾向を示す。
【００１５】
【発明の効果】
本発明によれば、道路交通騒音に対して優れた吸音率を有する吸音構造体を効率的に得ることができる。
【図面の簡単な説明】
【図１】本発明に係る吸音構造体の断面図である。
【図２】グラスウール厚さと道路交通騒音重み付け吸音率との関係を示す図である。
【図３】グラスウール厚さと道路交通騒音重み付け吸音率との関係を示す図である。
【図４】グラスウール厚さと道路交通騒音重み付け吸音率との関係を示す図である。
【図５】第１層と第２層のグラスウールそれぞれのかさ比重と道路交通騒音重み付け吸音率との関係を示す図である。
【図６】第１層と第２層のグラスウールそれぞれのかさ比重と道路交通騒音重み付け吸音率との関係を示す図である。
【図７】そのなかで特に高い吸音率が得られる範囲を示す図である。
【図８】第１層と第２層のグラスウールそれぞれの厚さと道路交通騒音重み付け吸音率との関係を示す図である。
【図９】第１層と第２層のグラスウールそれぞれの厚さと道路交通騒音重み付け吸音率との関係を示す図である。
【図１０】そのなかで、特に高い吸音率が得られる範囲を示す図である。
【図１１】表面空気層及び背後空気層と道路交通騒音重み付け吸音率との関係を示す図である。
【図１２】表面空気層及び背後空気層と道路交通騒音重み付け吸音率との関係を示す図である。
【図１３】道路交通騒音の加重値Ｌｉと周波数の関係を示す図である。
【符号の説明】
１ 枠体
２ 多孔板
３、４ 繊維質吸音材
９ 表面空気層
１０ 背後空気層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sound-absorbing structure for reducing road traffic noise, for example, a sound-absorbing structure suitable as a sound-absorbing plate on the backside of a viaduct.
[0002]
[Prior art]
Measures against road traffic noise have become important, and various measures have been taken. For example, a soundproof wall having a height of about 5 m is built between a road and a residential area, and a drainage pavement capable of reducing generation of noise is provided. In addition, on the road that is connected to the viaduct road, noise from vehicles traveling on the ground is reflected on the backside of the viaduct and causes noise in the residential area. I have. In addition, noise from openings will affect roadside residential areas even on semi-underground splitting roads and tunnel roads. ing.
[0003]
Japanese Patent Application Laid-Open Nos. Hei 10-25713, Hei 9-316831, Hei 9-111910, Hei 7-90816, and the like disclose sound absorbing structures used for road traffic noise. Have been.
Among these various sound absorbing structures, a sound absorbing material including a frame, a fibrous sound absorbing material such as glass wool, a protective film for covering the fibrous sound absorbing material for preventing scattering and waterproofing of fibers, and a perforated plate for protecting the front surface thereof. Structures are commonly used and inexpensive. Further, it is also known that it is effective to form a sound absorbing material having a different bulk specific gravity into a laminated structure in order to effectively increase the sound absorbing coefficient over a wide frequency band.
[0004]
[Problems to be solved by the invention]
The sound absorbing structure used for road traffic noise is required to have a very high sound absorption coefficient over a wide frequency band, and a reference value of the sound absorption coefficient is provided according to the installation location. Conventionally, the above components are appropriately combined for each installation location to which the sound absorbing structure is applied, and a structure satisfying a reference value applied to the installation location is found from among them. However, in this case, it is not known whether the found structure of the sound absorbing structure is optimal. That is, there may be a structure having the same thickness as the sound absorbing structure and further excellent sound absorbing performance, or there may be a structure capable of further reducing the thickness if the sound absorbing structure has the same sound absorbing performance.
[0005]
In view of the current situation in which a sound absorbing structure having a thickness as thin as possible and having a good sound absorbing performance is desired due to the constraints of costs and building limits, the present invention can specifically improve the sound absorbing coefficient with respect to road traffic noise. It is an object of the present invention to find a suitable sound absorbing structure and to obtain a sound absorbing structure having an excellent sound absorbing coefficient.
[0006]
[Means for Solving the Problems]
The sound-absorbing structure according to the present invention is a sound-absorbing structure having a perforated plate disposed in front of a frame and a fibrous sound absorbing material disposed in the frame, wherein the fibrous sound absorbing material is flat and has a thickness of 50%. １１０110 mm, covered with a plastic film, and further provided with an air layer having a thickness of 10 mm〜30 mm between the perforated plate and the fibrous sound absorbing material. In this case, an air layer is further provided between the fibrous sound absorbing material and the back plate of the frame, and when the thickness of the air layer is 30 mm or less, a high sound absorption coefficient is obtained.
Further, in the above sound absorbing structure, two layers of fibrous sound absorbing materials each covered with a plastic film are laminated in the front and rear, and the total thickness is desirably 50 to 110 mm. In that case, the first layer (front side) The sound absorption coefficient is particularly high when the thickness of the fibrous sound absorbing material of (2) is 25 mm or more. Further, in this case, when both the front and rear fibrous sound absorbing materials are glass wool, it is desirable that the bulk density be in a region surrounded by a to h in FIG.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to FIGS.
First, FIG. 1 shows an example of a sound absorbing structure (a cross section perpendicular to the longitudinal direction) according to the present invention. For example, a sound absorbing structure that is hung downward below a bridge of a viaduct and that is attached in a plural number to each other is attached. It is a structure.
This sound absorbing structure comprises a hollow frame formed of a
The frame, the perforated plate and the like may be made of an iron plate, a stainless steel plate or the like in addition to aluminum. These can be manufactured not only from an extruded material but also from a rolled material, and the frame and the perforated plate can be integrally formed by an extruded shape.
[0008]
The fibrous
Although not shown in FIG. 1, as described in Japanese Patent Application Laid-Open No. 9-111910, for example, a vibration damping material such as bituminous resin or rubber resin is attached to the inside of the frame. May be provided.
[0009]
Subsequently, it will be described with reference to FIGS. 2 to 13 that the sound absorbing structure according to the present invention exhibits an excellent sound absorbing coefficient.
In the present invention, the sound absorption coefficient of the sound absorbing structure was determined by the transfer matrix method. This means that a transmission matrix is created for each component of the sound absorbing structure (in the case of one layer of glass wool, perforated plate, air layer, protective film, glass wool, protective film, air layer) in order from the sound incident side, and these are combined. Then, a transmission matrix of the sound absorbing structure is created, and the impedance Z of the surface (the outer surface of the perforated plate) is calculated under the condition of the rigid wall at the end (the rear plate of the frame). At this time, the aperture ratio of the perforated plate was 60%, the plate thickness was 2 mm, the hole diameter was 8 mm, the protective film was a polyvinyl fluoride film (thickness: 12 μm, the surface density: 20 g / m 2 ), and the sound speed in glass wool was The effective density was measured using an acoustic tube at each frequency indicated by points in FIG. 13 to determine the surface impedance Z. From the following equation (1), the normal incidence sound absorption coefficient αi of the sound absorption structure can be calculated for each frequency. It has been confirmed by the present inventors that the normal incidence sound absorption coefficient obtained by this method substantially coincides with the actually measured normal incidence sound absorption coefficient of the sound absorbing structure.
(Equation 1)
Further, from the relationship between the weight value Li of the road traffic noise and the frequency shown in FIG. 13, the road traffic noise weighted sound absorption coefficient α (weighted average value based on the frequency characteristics of the road traffic noise) is calculated based on the following equation (2). .
(Equation 2)
2 to 4 show glass wool when the surface air layer (the air layer between the frame and the glass wool) and the back air layer (the air layer between the glass wool and the back plate of the frame) are 0 mm, 10 mm, and 20 mm, respectively. It is the figure which showed the relationship between thickness (only one layer) and road traffic noise weighted sound absorption coefficient. In the figure, GW24K to GW64K indicate the bulk specific gravity of commercially available glass wool (24 kg / m 2 to 64 kg / m 2 ). As shown in FIGS. 2 to 4, even if the bulk specific gravity of the glass wool is different, the sound absorption coefficient increases from around 50 mm in thickness, and even if it exceeds 100 mm, the increase in sound absorption coefficient cannot be expected so much. Therefore, the glass wool layer may have a thickness of 50 to 110 mm, preferably 75 to 100 mm. Further, when there is no air layer on the surface and behind, the sound absorption coefficient is lower as a whole than when there is an air layer.
In this example, the glass wool layer was a single layer. However, when the glass wool layer was formed as a multilayer or when another fibrous sound absorbing material (rock wool, non-woven fabric, etc.) was used, almost the same tendency was exhibited. When the thickness is 50 to 110 mm, preferably 75 to 100 mm, a high sound absorption coefficient can be efficiently obtained. Even if the aperture ratio of the perforated plate and the thickness of the protective film (for example, a polyvinyl fluoride film has a thickness of 21 μm, for example) change, the sound absorption coefficient shows almost the same tendency, and is excellent within the above numerical range. (The same can be said for FIGS. 5 to 12 described later).
[0012]
FIGS. 5 to 6 show that the surface air layer and the back air layer each have a thickness of 20 mm, and two layers of glass wool are laminated before and after the first layer glass wool and the second layer glass wool have a thickness of 37.5 mm (total 75 mm) or 50 mm, respectively. The relationship between the bulk specific gravity of each of the first and second layers of glass wool and the road traffic noise weighted sound absorption coefficient when (total 100 mm) is set is shown. In the figure, the sound absorption coefficient is shown by contour lines in increments of 0.01. FIG. 7 shows a range in which a high sound absorption coefficient can be obtained, from which the sound absorption coefficient is high in a range surrounded by a to h (within a thick line), and a to b, i, and The sound absorption coefficient is even higher in the range surrounded by j, f to h (within the diagonally inclined line to the left), and the range surrounded by the lines i, k, l, j and b, k, l, g (to the lower right). In the hatched area), a more excellent sound absorption coefficient is shown. In addition, a to h indicate respective intersections of 16K to 64K lines on the horizontal axis and 16K to 80K lines on the vertical axis.
[0013]
8 to 9 show that the bulk density of the first layer glass wool is 32 kg / m 3 , the bulk density of the second layer glass wool is 48 kg / m 3 or 64 kg / m 3, and both the surface air layer and the rear air layer are 20 mm. The relationship between each glass wool thickness and the road traffic noise weighted sound absorption coefficient is shown. In the figure, the sound absorption coefficient is shown by contour lines in 0.005 increments. FIG. 10 shows a range in which a high sound absorption coefficient can be obtained from among them. When the thickness of the first layer is X and the thickness of the second layer is Y, sound absorption is approximately in a range of X + Y ≧ 50. When the ratio suddenly increases and exceeds X + Y ≧ 110, the improvement in the sound absorption ratio is small. In particular, a high sound absorption coefficient can be efficiently obtained in the range of X ≧ 30, and further in the range of X ≧ 50 and X + Y ≦ 100.
In this example, both layers are glass wool layers. However, even when other fibrous sound absorbing materials (rock wool, nonwoven fabric, etc.) are used, almost the same tendency is exhibited. Further, even when the thickness of the surface and the thickness of the air layer behind change, the same tendency is exhibited.
[0014]
11 to 12 show a case where the bulk specific gravity of the first layer glass wool is 32K, the bulk specific gravity of the second layer glass wool is 48K, the thickness of the first layer is 25 mm or 50 mm, and the thickness of the second layer is 25 mm. And the relationship between the surface air layer and the rear air layer and the road traffic noise weighted sound absorption coefficient. In the figure, the sound absorption coefficient is shown by contour lines in 0.005 increments. The surface air layer and the back air layer are preferably as thin as possible in the sense of reducing the thickness of the sound absorbing structure, but in order to improve the sound absorption efficiency efficiently, the surface air layer should be 10 mm to 30 mm. desirable. The back air layer may be 30 mm or less. In this example, both layers are glass wool layers. However, even if this is a single layer, even when the bulk specific gravity of glass wool is changed, or when another fibrous sound absorbing material (rock wool, nonwoven fabric, etc.) is used, it is almost impossible. It shows a similar tendency.
[0015]
【The invention's effect】
According to the present invention, it is possible to efficiently obtain a sound absorbing structure having an excellent sound absorption coefficient against road traffic noise.
[Brief description of the drawings]
FIG. 1 is a sectional view of a sound absorbing structure according to the present invention.
FIG. 2 is a diagram showing a relationship between glass wool thickness and road traffic noise weighted sound absorption coefficient.
FIG. 3 is a diagram showing the relationship between glass wool thickness and road traffic noise weighted sound absorption coefficient.
FIG. 4 is a diagram showing a relationship between glass wool thickness and road traffic noise weighted sound absorption coefficient.
FIG. 5 is a diagram showing the relationship between the bulk specific gravity of each of the first and second layers of glass wool and the road traffic noise weighted sound absorption coefficient.
FIG. 6 is a diagram showing the relationship between the bulk specific gravity of each of the first and second layers of glass wool and the road traffic noise weighted sound absorption coefficient.
FIG. 7 is a diagram showing a range in which a particularly high sound absorption coefficient is obtained.
FIG. 8 is a diagram showing the relationship between the thickness of each of the first and second layers of glass wool and the road traffic noise weighted sound absorption coefficient.
FIG. 9 is a diagram showing the relationship between the thickness of each of the first and second layers of glass wool and the road traffic noise weighted sound absorption coefficient.
FIG. 10 is a diagram showing a range in which a particularly high sound absorption coefficient is obtained.
FIG. 11 is a diagram showing a relationship between a surface air layer and a rear air layer, and a road traffic noise weighted sound absorption coefficient.
FIG. 12 is a diagram showing a relationship between a surface air layer and a rear air layer, and a road traffic noise weighted sound absorption coefficient.
FIG. 13 is a diagram illustrating a relationship between a weight Li of road traffic noise and a frequency.
[Explanation of symbols]
DESCRIPTION OF
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10838198A JP3601575B2 (en) | 1998-04-20 | 1998-04-20 | Sound absorbing structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10838198A JP3601575B2 (en) | 1998-04-20 | 1998-04-20 | Sound absorbing structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11305781A JPH11305781A (en) | 1999-11-05 |
| JP3601575B2 true JP3601575B2 (en) | 2004-12-15 |
Family
ID=14483339
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10838198A Expired - Lifetime JP3601575B2 (en) | 1998-04-20 | 1998-04-20 | Sound absorbing structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3601575B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11608291B2 (en) | 2016-11-04 | 2023-03-21 | Corning Incorporated | Micro-perforated panel systems, applications, and methods of making micro-perforated panel systems |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006241775A (en) * | 2005-03-02 | 2006-09-14 | Nippon Steel Metal Prod Co Ltd | Radio wave and acoustic wave absorbing panel for viaduct under-girder |
| JP4906318B2 (en) * | 2005-11-11 | 2012-03-28 | 学校法人早稲田大学 | Low frequency sound absorber made of closed cell glass foam |
| CN103072588B (en) * | 2011-12-13 | 2016-04-13 | 隋富生 | For the micropunch transparent panel sound absorber of high speed train glass partition and door |
| JP7449711B2 (en) * | 2020-02-18 | 2024-03-14 | 公益財団法人鉄道総合技術研究所 | Sound absorbing material structure |
| JP7409970B2 (en) * | 2020-06-01 | 2024-01-09 | 積水化学工業株式会社 | Sound absorption structure |
-
1998
- 1998-04-20 JP JP10838198A patent/JP3601575B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11608291B2 (en) | 2016-11-04 | 2023-03-21 | Corning Incorporated | Micro-perforated panel systems, applications, and methods of making micro-perforated panel systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11305781A (en) | 1999-11-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2848587B2 (en) | Sound-absorbing damping material | |
| US5031721A (en) | Sound absorption barriers | |
| JP3601575B2 (en) | Sound absorbing structure | |
| JP2865275B2 (en) | Noise barrier | |
| JP2003295867A (en) | Sound absorption structure | |
| JP4019820B2 (en) | Sound absorbing structure | |
| JP2000129636A (en) | Double-faced sound absorbing plate | |
| JP3806565B2 (en) | Soundproofing device | |
| JPH10331286A (en) | Composite sound absorbing panel | |
| JP3065561B2 (en) | Sound absorbing material and sound absorbing panel | |
| JPH03293409A (en) | Sound absorption and insulation panels | |
| JPH116223A (en) | Sound absorbing structure | |
| JPH0226973Y2 (en) | ||
| JP3425827B2 (en) | Metal porous sound absorbing plate | |
| JP3806566B2 (en) | Soundproofing device | |
| JP3159667B2 (en) | Road sound absorbing structure | |
| JP3914382B2 (en) | Sound insulation wall | |
| JP3833036B2 (en) | Thin soundproof panel | |
| JP3843389B2 (en) | Sound absorbing structure | |
| JP2766600B2 (en) | Twice-diffraction soundproof wall with expansion sound reduction room | |
| JP3236952B2 (en) | A scaffolding and sound absorption system on the underside of the girder on elevated roads | |
| JPH0596113U (en) | Sound absorbing sound insulation panel | |
| JP2753826B2 (en) | Sound absorbing material for viaduct | |
| JP2835014B2 (en) | Soundproofing unit | |
| JP3654809B2 (en) | Sound absorbing member |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040401 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20040901 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20040914 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20040914 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081001 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081001 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091001 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101001 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101001 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111001 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111001 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121001 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131001 Year of fee payment: 9 |
|
| EXPY | Cancellation because of completion of term |