JP3639214B2

JP3639214B2 - Soundproofing

Info

Publication number: JP3639214B2
Application number: JP2000606836A
Authority: JP
Inventors: 正基長谷部
Original assignee: Japan Science and Technology Agency; National Institute of Japan Science and Technology Agency
Current assignee: Japan Science and Technology Agency; National Institute of Japan Science and Technology Agency
Priority date: 1999-03-24
Filing date: 2000-03-24
Publication date: 2005-04-20
Anticipated expiration: 2020-03-24
Also published as: WO2000056980A1

Description

技術分野
本発明は、防音塀に係り、特に、戸外で利用される騒音低減用の遮音壁、防音塀に関するものである。
背景技術
従来の遮音壁や防音塀（本明細書では、これらを防音塀と総称する。）では、その側面周囲の音圧分布に関心が払われていなかった。主に行われていた研究は、防音塀上端部における音圧を小さくして、擬似的な音源とみなされる上端部からの音の放射を少なくするという発想によっており、上端部に吸音性を持たせたり、共鳴管によって音圧を小さくするといった工夫によるものであった。
発明の開示
しかしながら、従来の防音塀の上端部における音圧を小さくして、擬似的な音源と見なされる上端部からの音の放射を少なくするという発想では、この上端部のみの音圧低減対策だけでは特定周波数では逆効果になる等の不都合があった。そこで、本発明は、以上の点に鑑み、側面に管を多数配設し、擬似的な音源になる上端部の管の長さを短くすることで、管内部に定在波を作りだし、管前面位置での音圧分布を極小として、広い周波数範囲において良好な騒音低減効果を作り出すことを目的とする。さらに、本発明は、防音塀の側面に定在波を作り出す管を多数配置し、また、防音塀の上端部における管についてはその長さを調整することにより、最も防音塀としての効果が良好な音圧分布をつくり出すことを目的とする。
また、本発明は、半開放管及び／又は上端部管に、各管の内部に組み込まれて管を分割するための複数の小半開放管をさらに備えることで、減衰効果を一層高い周波数まで拡大することを目的とする。さらに、本発明は、防音塀の壁端部に複数種類の管を設けることで、一層の防音性能向上を図ることを目的とする。また、本発明は、水平方向にある仕切りを間引くことで、構成を簡易とし、工費を削減することを目的とする。
本発明の解決手段によると、
壁部と、
前記壁部の側面に多数配置され、一方が前記壁部により閉じられており、他方が開いている半開放管と、
前記壁部の側面上端に配置され、一方が前記壁部により閉じられており、他方が開いている前記半開放管より短い上端部管を備え、
前記上端部管の音源側前面位置付近で音圧分布が極小となるように、前記上端部管の長さを前記半開放管の長さより短くした防音塀を提供する。
また、本発明において、
前記半開放管及び／又は前記上端部管は、
各管の内部に組み込まれて管を分割するための、前記半開放管又は前記上端部管より短く断面積の小さい複数の小半開放管をさらに備えるようにしてもよい。
また、本発明において、
音源側、受音側又はこれら両側に、複数種の長さの複数の半開放管を有する壁端部をさらに備えるようにしてもよい。
また、本発明において、
前記半開放管、前記上端部管又は前記小開放管等は、
配列の水平方向が垂直方向より長い断面形状を有するようにしてもよい。
【図面の簡単な説明】
図１は本発明に係る防音塀の全体構成図。
図２は音源及び防音塀の配置説明図。
図３は図２の防音塀１０先端部のｘｚ断面での部分拡大図。
図４は音圧分布の説明図。
図５は本発明に係る防音塀１０の模型実験の説明図。
図６は単壁との挿入損失の比較説明図（１）。
図７は単壁との挿入損失の比較説明図（２）。
図８は本発明の第２の実施の形態の説明図。
図９は本発明の第３の実施の形態の全体構成図。
図１０は本発明の第３の実施の形態の壁端部の構成図。
図１１は単壁との挿入損失の比較説明図（３）。
図１２は本発明の第４の実施の形態の壁端部の構成図。
図１３は単壁との挿入損失の比較説明図（４）。
図１４は本発明の第５の実施の形態の説明図。
図１５は本発明の第６の実施の形態の説明図。
発明を実施するための最良の形態
図１に、本発明に係る防音塀の全体構成図を示す。
防音塀１０は、上端板３２、横板３３、縦板３１、半開放管２及び上端部管３を備えている。半開放管２は、上下の横板３３及び左右の縦板３１により囲まれることで構成されるものである。上端部管３は、最上部の半開放管２を形成する横板３３と左右の縦板３１と上端板３２により囲まれることで構成され、上端部管３の上面は、下面よりも短くなっている。図中、縦板３１の高さは、ここでは一例として、３ｍとしてあり、横板３１の長さ、すなわち、半開放管２の長さはｗとし、半開放管２及び上端部管３の内径はｄとする。防音塀１０の断面図は、櫛形をしており、図からもわかるように、角柱型の管又は直方管等をいくつも積み重ねたような構成となっている。なお、図中の矢印は、例えば、自動車の進行方向を表す。
また、半開放管２は、上下の横面板及び左右の縦面板で囲むことにより、ひとつのユニットを形成し、防音塀１０は、それを複数ユニット備えるようにしてもよい。上端部管３も同様に、下面板、下面板より短い上面板、左右縦面板により囲まれることで、ひとつのユニットを形成し、防音塀１０は、それを複数ユニット備えるようにしてもよい。また、縦面板及び横面板等の長さを調節することによって、半開放管２又は上端部管３をひとつずつのユニットではなく、縦又は横の複数又は全ての半開放管２又は上端部管３で１単位のブロックとし、そのブロックを横に並べていくか、又は、縦に積み重ねていくことにより、防音塀１０を構成してもよい。なお、半開放管２又は上端部管３の管の断面形状は、正方形、長方形、ひし形、円形、楕円形、これらの変形管等の適宜のものを用いることができる。さらに、横方向の防音効果を得るため、上端部管３と同様の構成を横方向に設けるようにしてもよい。
図２に、音源及び防音塀の配置説明図を示す。この図では、防音塀１０は、断面図で示されている。
防音塀１０は、壁部４、半開放管２及び上端部管３を備える。この半開放管２は、壁部４の側面に多数が配置されており、壁部４側が閉じているものである。上端部管３は、壁部４の上端に配置されており、管の長さは半開放管２より短くなっているものである。
図３に、図２の防音塀１０先端部のｘｚ断面での部分拡大図を示す。
壁部４の側面には、多数の半開放管２と上端部管３が配置されている。
各半開放管２の長さｌ及び上端部管１の長さｌ’によって制御の対象とする音の周波数帯域が決定される。ここで、ｌ／ｌ’＝ｎの場合、その音の下限周波数をｆ_Ｌ、その音の上限周波数をｆ_H、音速をｃとすれば、それらは以下の式により求められる。
ｆ_Ｌ＝ｃ／（４・ｌ）
ｆ_H＝ｃ／（４・ｌ’）＝ｎ・ｃ／（４・ｌ）
図では、一例として、各半開放管２の内径ｄは、長さｌの１／２以下にしてある。上端部管３の長さｌ’は、半開放管２の長さｌの１／３程度となっており、上端部管３の内径は半開放管２の内径ｄと同じである。この場合、下限周波数ｆ_Ｌ及び上限周波数ｆ_Hは、以下の式により求められる。
ｆ_Ｌ＝ｃ／（４・ｌ）
ｆ_Ｈ＝３・ｃ／（４・ｌ）
なお、上端部管３の上面の長さは半開放管２の管の長さよりも短いものであればよく、ここでは、半開放管２の長さの１／３を例として説明をしているが、これに限られるものではなく、制御対象音の周波数範囲、音源の位置、状況、壁及び管の材料、厚さ等により防音、遮音効果を発揮するように適宜設定することができる。
一例として、２００〜６００Ｈｚ対応の防音塀では、次のように設計することができる。すなわち、例えば、防音塀１０は、高さ３ｍとして、音源１から２ｍのところに配置されることができる。さらに、一例として、上端部管２の長さｌ’は０．１４２９ｍ、半開放管３の長さｌは０．４２８８ｍ、各半開放管２及び上端部管３の内径ｄは０．１６ｍ、各半開放管２の厚みは０．０４ｍとすることができる。そして、この場合、壁部４の厚みと半開放管の長さｌを足した壁部４からの長さ、すなわち、防音塀１０全体の厚みｗは０．４６８８ｍとなる。
図２及び図３のように、半開放管２は、防音塀１０の壁部４の側面に多数配置されており、各半開放管２及び上端部管３の音源１側は開いており、壁部４に接している部分は閉じている。
壁部４の側面の各半開放管２は、内部に定在波をつくり出し、節と腹が常に存在することとなる。この定在波は、防音塀１０の壁部４側面に縦横に並んだ多数の半開放管２に共通に存在することになり、防音塀１０の壁部４側面全体に一定の音圧分布をもたらす。また、各半開放管２の内部では、定在波により音圧分布が極小となる部分ができる。この定在波は、防音塀１０の壁部４側面に沿っての音圧分布を均一にし、定在波による音圧分布は、上端部管３の前面の位置まで連続して生成される。防音塀１０の上端では、上端部管３の音圧分布が、いわば、”はみ出し”となって存在し、防音塀１０上端部では、音圧の小さい部分が存在することとなる。上端部に配置された上端部管３では、各半開放管２と同様に、その内部に定在波をつくり出すが、上端部管３の長さを半開放管２より短くすることにより防音塀１０の上端部の前面位置での音圧分布が極小となるようにしてある。この極小部分の防音塀１０側面から水平方向への距離は、側面の上端部管３の効果によって上端部管３の開口部及び上端部管３内部に生じさせられた極小音圧部分のものと一致する。
上述のように、防音塀１０の壁部４側面では、定在波による音圧分布均一のため、防音塀１０上端部の前面位置での音圧分布が極小となるように構成される。この音圧分布の均一及び極小により、上端部付近での極小音圧分布が広い周波数範囲において保持されるため、擬似的な音源とみなされる上端部からの音の放射が少なくなり、良好な騒音低減効果が得られる。
図４に、音圧分布の説明図を示す。
図示のように、音源１からの騒音に対して、極小音圧部分ａが分布される。また、上端部管３の疑似音源部分ｂ付近では、極小音圧部分ａにより、常に音圧が低くなるため、回折音が小さくなる。
図５に、本発明に係る防音塀１０の模型実験の説明図を示す。
音源１からの音は、防音塀１０を介して受音点１１で測定される。実験は、防音塀１０から音源１までの距離をＸｓ、受音点１１までの距離をＸｒとして行った。
図６及び図７に、それぞれ単壁との挿入損失の比較説明図（１）及び（２）を示す。
なお、図６及び図７は、実際の寸法の１／１０縮尺で、図５に示したような模型による実験の結果を表している。また、防音塀１０は、一例として、２００〜６００Ｈｚ対応遮音壁について設計した。図６では、防音塀１０からの音源１及び受音点１１までの距離は、それぞれＸｓ＝２ｍ及びＸｒ＝２ｍとして実験を行った。図７では、防音塀１０からの音源１及び受音点１１までの距離は、それぞれＸｓ＝４ｍ及びＸｒ＝４ｍとして実験を行った。また、図６及び図７の両方とも、防音塀１０の高さは３ｍ、厚さｗは０．４６８８ｍとして実験を行った。防音塀１０の厚さは、比較を明確にするために厚くしてあり、この厚さに限られるものではない。
図６及び図７において、横軸は、実寸の周波数を表しており、ここでは、一例として、模型において１００−１０００Ｈｚの範囲を示す。また、縦軸は、挿入損失であり、防音塀１０がない場合の音圧レベルを基準に、防音塀１０を立てたときの音圧レベルを、すなわち、音圧が何デシベル下がるかを示したものである。
図６及び図７中、点線は通常の単壁による防音塀についての結果を、実線は本発明に係る防音塀１０についての結果を表している。図からわかるように、図６及び図７の両方とも、例えば、１００Ｈｚ以上、特に、対応遮音周波数の２００〜６００Ｈｚ、３００Ｈｚ以上で明確に良い結果が現れていることがわかる。
図８に、本発明の第２の実施の形態の説明図を示す。
図８（Ａ）は、図示のように、図１における防音塀１０での上端部管３において、左右の縦面板である仕切りがない場合の図を示している。図８（Ｂ）に示したものは、図８（Ａ）の上端部管３の底面と半開放管２の上面とが、共用されている場合を示している。
図９に、本発明の第３の実施の形態の全体構成図を示す。
この例では、半開放管２及び上端部管３は、各管の内部に組み込まれて管を分割するための複数の小半開放管１２０及び１０１をそれぞれ備える。また、小半開放管１０１の上部に、この例ではその約３．１分の１の長さを持つ小半開放管１０２を備える。複数の小半開放管１２０、１０１及び１０２は半開放管２及び上端部管３より短く断面積が小さい。複数の小半開放管１２０、１０１及び１０２により、より周波数の高い領域まで性能を上げることが出来る。
また、図１０に、本発明の第３の実施の形態の壁端部の構成図を示す。この図は、特に、図９における壁部４の上端である壁端部１００について拡大した図である。図中、壁部４の壁端部１００は、音源側及び受音側に、複数種の長さの複数の半開放管を備える。なお、壁端部１００は、音源側又は受音側のいずれか一方に複数の半開放管を有するようにしてもよい。また、音源側では、半開放管２にも、さらに短い管配列を設けた。上述の実施の形態では、防音塀の音源側に管配列を設けるようにしたものであったが、この実施の形態では、さらにそれらの管の内部により短い管を組み込んだ。
まず、壁端部１００の音源側について説明する。壁端部１００は、音源側に、複数の第１の小半開放管１０１と、端部に配置されて第１の小半開放管１０１より短い第２の小半開放管１０２とを備える。複数の第１の小半開放管１０１が、上端部管３の内部に組み込まれて、上端部管３を分割する。ここでは一例として、小半開放管１２０、１０１の管長は、半開放管２の１／３程度（上端部管３と同程度）とし、管径は、半開放管２及び上端部管３の１／２から１／３程度とした。また、小半開放管１０２の管長は、ここでは一例として、小半開放管１０１の１／３程度、管径は同程度とした。このような組子構造をとると、制御周波数範囲が拡大する。上端部管３の管長をｌ_３、小半開放管１０２の管長をｌ_１０２とするとし、ｌ_３／ｌ_１０２＝ｎ‘とすると、制御の上限周波数は小半開放管１０２を備えたことにより、ｎ’倍に拡大する。なお、管の太さ（直径）は、直径方向にモードが立たない周波数までを制御対象とするように設定している。例えば、壁端部１００の音源側に、２８．３ｃｍの管と、９．４ｃｍの管の２つの管を用いると、制御対象とする周波数は、約９００Ｈｚとなる。第３の実施の形態では、一例として、３．０ｃｍの長さの管を最上部にさらに設定し、９．４ｃｍの管を２段設定とした。これにより制御する最高周波数は、音の波長の１／４が最上部の管の長さに一致する周波数（即ち、約２８００Ｈｚ）まで高めることが期待できる。
つぎに、壁端部１００の受音点側について説明する。本発明では、さらに、壁端部１００の受音点側に管配列を設定する。すなわち、壁端部１００は、受音側に、第３の小半開放管１０３と、第３の小半開放管１０３より端部側に配置されてそれより短い第４の小半開放管１０４と、端部に配置されて第４の小半開放管１０４と開放端面の位置を等しく又は略等しくして且つそれより長い第５の小半開放管１０５とを備える。上述のように音源側のみに管配列がある場合、その挿入損失（防音塀を建てた場合に建てない場合より低下する音圧レベル値）は、特定の周波数において小さい（防音性能が劣る）場合が生じる。それを解消するため、防音塀の背後、即ち、受音点側の壁先端部付近に、防音性能が劣る特定の周波数の音の定在波の節が生じるように長さを設定した音響管を配列する。壁端部１００の受音点側の管の長さは、一例として、上述の式を参照すると、１２ｃｍのものは７００Ｈｚに、７ｃｍのものは１２００Ｈｚに、１４ｃｍのものは６００Ｈｚの音に対応することができる。
図１１に、単壁との挿入損失の比較説明図（３）を示す。太い実線が今回の防音塀、細い実線が単壁の結果である。なお、図１１及び後述の図１４は、実際の寸法の１／１０縮尺で、図５に示したような模型による実験の結果を表している。図１１及び図１４において、横軸は、実寸の周波数を表しており、ここでは、一例として、模型において１００−１０００Ｈｚの範囲を示す。また、縦軸は、挿入損失であり、防音塀１０がない場合の音圧レベルを基準に、防音塀１０を立てたときの音圧レベルを、すなわち、音圧が何デシベル下がるかを示したものである。図示のように、例えば、１００Ｈｚ以上、特に、対応遮音周波数の約１３０〜３８０Ｈｚ及び約４００Ｈｚ以上で、明確に良い結果が現れていることがわかる。
図１２に、本発明の第４の実施の形態の壁端部の構成図を示す。
図１２（ａ）に示されるように、壁部４は、その上端に傾斜面４１を有する。壁端部１１０は、傾斜面４１から垂直又は略垂直に延びるように形成される。壁端部１１０は、音源側に、複数の第１の小半開放管１１１と、端部に配置されて第１の小半開放管１１１より短い第２の小半開放管１１２とを備え、さらに第２の半開放間１２より短い第６の小半開放管１１６を備えることができる。また、受音側に、第３の小半開放管１１３と、第３の小半開放管１１３より端部側に配置されてそれより短い第４の小半開放管１１４と、端部に配置されて第４の小半開放管１１４と開放端面の位置を等しく又は略等しくして且つそれより長い第５の小半開放管１１５とを備える。壁端部１１０は、壁端部１００と同様であり、受音点側又は音源側の一方のみに小半開放管を設けるようにしても良い。また、図１２（ｂ）に、各管の長さ及び幅についてのデータを示す。これらデータは、あくまでも一例にすぎず、設計条件、環境、材料、大きさ、等により適宜設定することができる。
上述の第３の実施の形態では、地面に対して垂直に近い形状の防音塀を基本としていた。第４の実施の形態では、防音塀の上部を部分的に音源と反対側（受音点側）へ傾けた傾斜形状を備えた防音塀についての構成である。傾斜防音塀についても、上述のような音源側、受音点側、及びこれら両側に管配列を設けることで、音響的性能が良好になる。
図１３に、単壁との挿入損失の比較説明図（４）を示す。太い実線が今回の防音塀、点線が単壁の結果である。図示のように、特に、対応遮音周波数の約３００以上で、明確に良い結果が現れていることがわかる。
つぎに、図１４に、本発明の第５の実施の形態の説明図を示す。
この実施の形態は、各管について水平方向の仕切を間引くようにして、図示のような正面図で表される防音塀を構成したものである。すなわち、図１４（ａ）では、略正方形の断面の管が配列されているが、図１４（ｂ）では、縦板が間引かれて、長方形の断面の管が配列されている。音源の性質によって、例えば、道路交通騒音、鉄道騒音等のように、水平方向に音場があまり変化しない場合がある。この場合には、管配列の水平方向にある仕切を間引いても挿入損失はあまり変化しない。すなわち、各管の断面形状を横長の長方形等になる。なお、上述の半開放管２、上端部管３、第１乃至第５の小半開放管１０１〜１０５又は小半開放管１２０等についても、適宜、配列の水平方向が垂直方向より長い断面形状を有するようにすることができる。
つぎに、図１５に、本発明の第６の実施の形態の説明図を示す。
上述の実施の形態では、図１５（ａ）に示すような半開放管２及び上端部管３に対して、さらに、図１５（ｂ）に示すような小半開放管１２０及び１０１を設け、さらに上端部管３の上に小半開放管１０２を設けた。本発明では、図１５（ｃ）に示すように、小半開放管１２０及び１０１、１０２を分割するように、さらに小さい半開放管１２２、１０６及び１０７を、それぞれ設け、さらに上の小半開放管１０２の上にさらに小さい半開放管１０８を設けた。また、このように、段階的にさらなる段数の組子構造とすることもできる。また、小半開放管を形成して組子構造とする部分は、全体的に構成しても、例えば、上部のみ、上部以外又は中間部のみというように、適宜部分的に構成しても良い。
なお、上述の実施の形態は、一例にすぎず、各種の半開放管・小半開放管及びその配列の個数、寸法、長さ、大きさ、位置、角度、断面形状、各管の配置順序、材質等は、適宜設定することができる。さらに、壁端部の各半開放管・小半開放管の段数、長さや断面積の大きさ等の種類等も、適宜設定することができる。また、各半開放管・小半開放管の断面形状は、正方形、長方形、ひし形、円形、楕円形、これらの変形管等の適宜のものを用いることができる。さらに、横方向の防音効果を得るため、壁端部１００、１１０と同様の構成を横方向に設けるようにしてもよい。さらに、壁端部１００の上端の開放管の上面の長さはそれより下の半開放管・小半開放管の管の長さよりも短いものであればよく、ここでは、下の半開放管・小半開放管の長さの約１／３等を例として説明をしているが、これに限られるものではなく、制御対象音の周波数範囲、音源の位置、状況、壁及び管の材料、厚さ等により防音、遮音効果を発揮するように適宜設定することができる。
また、水平の半開放管が戸外にあると、そこに雨がたまる又は粉塵などのゴミがたまる等の場合が考えられる。そこで、メインテナンス上このような場合の対策として、半開放管、上端部管等は、若干下向きに又は左右どちらかが下がって、雨水等が滑らかに排出されるように構成することができる。その際、管配列の行又は列の全体を斜めに形成したり、個々の管を斜めに形成したりすればよい。さらに、各々の管の肉厚を調整することで、傾斜を形成することもできる。また、防音塀の全部又は一部に、ゴミ、ホコリ、雪、雨、風を避けるための音響的に透明な（音の伝播を妨げない）カバーを設けるようにしても良い。カバーとしては、例えば、細かい目のネット、網等を用いることができる。
産業上の利用可能性
本発明によると、側面に管を多数配設し、擬似的な音源になる上端部の管の長さを短くすることで、管内部に定在波を作りだし、管前面位置での音圧分布を極小として、広い周波数範囲において良好な騒音低減効果を作り出すことができる。さらに、本発明によると、防音塀の側面に定在波を作り出す管を多数配置し、また、防音塀の上端部における管についてはその長さを調整することにより、最も防音塀としての効果が良好な音圧分布をつくり出すことができる。
また、本発明によると、半開放管及び／又は上端部管に、各管の内部に組み込まれて管を分割するための複数の小半開放管をさらに備えることで、減衰効果を一層高い周波数まで拡大することができる。さらに、本発明によると、防音塀の壁端部に複数種類の管を設けることで、一層の防音性能向上を図ることができる。また、本発明によると、水平方向にある仕切りを間引くことで、構成を簡易とし、工費を削減することができる。TECHNICAL FIELD The present invention relates to a soundproof wall, and more particularly, to a soundproof wall and a soundproof wall for noise reduction used outdoors.
Background Art Conventional sound insulation walls and soundproof walls (in the present specification, these are collectively referred to as soundproof walls) have not paid attention to the sound pressure distribution around the side surface. The main research has been based on the idea of reducing the sound pressure at the upper end of the soundproof cage and reducing the sound emission from the upper end, which is regarded as a pseudo sound source. Or by reducing the sound pressure with a resonance tube.
However, the idea of reducing the sound pressure at the upper end portion of the conventional soundproof rod to reduce the sound emission from the upper end portion regarded as a pseudo sound source is a measure for reducing the sound pressure only at the upper end portion. However, there are inconveniences such as an adverse effect at a specific frequency. Therefore, in view of the above points, the present invention creates a standing wave inside the pipe by arranging a large number of pipes on the side surface and shortening the length of the pipe at the upper end that becomes a pseudo sound source. The object is to create a good noise reduction effect in a wide frequency range by minimizing the sound pressure distribution at the front surface position. Furthermore, the present invention has the most favorable effect as a soundproof rod by arranging a number of tubes that generate standing waves on the side surface of the soundproof rod and adjusting the length of the tube at the upper end of the soundproof rod. The purpose is to create a sound pressure distribution.
In addition, the present invention further includes a plurality of small half-open pipes that are incorporated in each pipe and divided into the half-open pipe and / or the upper end pipe, thereby expanding the attenuation effect to a higher frequency. The purpose is to do. Furthermore, an object of the present invention is to further improve the soundproofing performance by providing a plurality of types of pipes at the wall end of the soundproofing cage. Another object of the present invention is to simplify the configuration and reduce the construction cost by thinning out the partitions in the horizontal direction.
According to the solution of the present invention,
The wall,
A semi-opened tube which is arranged in a large number on the side of the wall, one is closed by the wall and the other is open;
An upper end pipe that is disposed at the upper end of the side surface of the wall, one is closed by the wall and the other is open than the half-open pipe;
Provided is a soundproof rod in which the length of the upper end tube is shorter than the length of the semi-open tube so that the sound pressure distribution is minimized near the sound source side front surface position of the upper end tube.
In the present invention,
The semi-open tube and / or the upper end tube are:
A plurality of small semi-open tubes having a smaller cross-sectional area than the semi-open tube or the upper end tube may be further provided to divide the tube by being incorporated inside each tube.
In the present invention,
You may make it further provide the wall edge part which has several semi-open pipes of several types of length in the sound source side, a sound receiving side, or these both sides.
In the present invention,
The semi-open pipe, the upper end pipe, the small open pipe, etc.
The horizontal direction of the array may have a longer cross-sectional shape than the vertical direction.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a soundproofing kit according to the present invention.
FIG. 2 is an explanatory view of the arrangement of the sound source and the soundproof frame.
FIG. 3 is a partially enlarged view of the tip end portion of the soundproof rod 10 in FIG.
FIG. 4 is an explanatory diagram of sound pressure distribution.
FIG. 5 is an explanatory view of a model experiment of the soundproof fence 10 according to the present invention.
FIG. 6 is an explanatory diagram (1) for comparison of insertion loss with a single wall.
FIG. 7 is a comparative illustration (2) of insertion loss with a single wall.
FIG. 8 is an explanatory diagram of the second embodiment of the present invention.
FIG. 9 is an overall configuration diagram of the third embodiment of the present invention.
FIG. 10 is a configuration diagram of a wall end portion according to a third embodiment of the present invention.
FIG. 11 is a comparative illustration (3) of insertion loss with a single wall.
FIG. 12 is a configuration diagram of a wall end portion according to a fourth embodiment of the present invention.
FIG. 13 is a comparative illustration (4) of insertion loss with a single wall.
FIG. 14 is an explanatory diagram of the fifth embodiment of the present invention.
FIG. 15 is an explanatory diagram of the sixth embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 is an overall configuration diagram of a soundproof frame according to the present invention.
The soundproof rod 10 includes an upper end plate 32, a horizontal plate 33, a vertical plate 31, a semi-open tube 2 and an upper end tube 3. The semi-open tube 2 is configured by being surrounded by upper and lower horizontal plates 33 and left and right vertical plates 31. The upper end tube 3 is configured by being surrounded by a horizontal plate 33, a left and right vertical plate 31, and an upper end plate 32 that form the uppermost semi-open tube 2, and the upper surface of the upper end tube 3 is shorter than the lower surface. ing. In the drawing, the height of the vertical plate 31 is 3 m as an example here, the length of the horizontal plate 31, that is, the length of the semi-open tube 2 is w, and the height of the semi-open tube 2 and the upper end tube 3 is The inner diameter is d. The cross-sectional view of the soundproofing cage 10 has a comb shape, and, as can be seen from the figure, has a configuration in which a number of prismatic tubes or rectangular tubes are stacked. In addition, the arrow in a figure represents the advancing direction of a motor vehicle, for example.
In addition, the semi-open tube 2 may be surrounded by upper and lower horizontal plates and left and right vertical plates to form one unit, and the soundproof rod 10 may include a plurality of units. Similarly, the upper end pipe 3 may be surrounded by a lower surface plate, an upper surface plate shorter than the lower surface plate, and left and right vertical surface plates to form a single unit, and the soundproof rod 10 may include a plurality of units. Further, by adjusting the lengths of the vertical plate and the horizontal plate, the semi-open pipe 2 or the upper end pipe 3 is not a single unit, but a plurality of vertical or horizontal half-open pipes 2 or the upper end pipes. The soundproof fence 10 may be configured by forming one block at 3 and arranging the blocks side by side or stacking them vertically. As the cross-sectional shape of the semi-open tube 2 or the upper end tube 3, a suitable shape such as a square, a rectangle, a rhombus, a circle, an ellipse, or a deformed tube thereof can be used. Furthermore, in order to obtain a soundproofing effect in the lateral direction, a configuration similar to that of the upper end pipe 3 may be provided in the lateral direction.
FIG. 2 is a diagram for explaining the arrangement of the sound source and the soundproofing cage. In this figure, the soundproof rod 10 is shown in a sectional view.
The soundproof fence 10 includes a wall part 4, a semi-open pipe 2 and an upper end pipe 3. Many of the semi-open tubes 2 are arranged on the side surface of the wall 4 and the wall 4 side is closed. The upper end pipe 3 is arranged at the upper end of the wall part 4, and the length of the pipe is shorter than that of the semi-open pipe 2.
FIG. 3 is a partially enlarged view of the tip end portion of the soundproof rod 10 in FIG. 2 in the xz section.
A large number of half-open tubes 2 and upper end tubes 3 are arranged on the side surface of the wall portion 4.
The frequency band of the sound to be controlled is determined by the length l of each half-open tube 2 and the length l ′ of the upper end tube 1. Here, when l / l ′ = n, if the lower limit frequency of the sound is f _L , the upper limit frequency of the sound is f _H , and the speed of sound is c, they can be obtained by the following equations.
f _L = c / (4 · l)
f _H = c / (4 · l ′) = n · c / (4 · l)
In the figure, as an example, the inner diameter d of each half-open tube 2 is set to be ½ or less of the length l. The length l ′ of the upper end tube 3 is about ３ of the length l of the semi-open tube 2, and the inner diameter of the upper end tube 3 is the same as the inner diameter d of the semi-open tube 2. In this case, the lower limit frequency f _L and upper frequency f _H is obtained by the following equation.
f _L = c / (4 · l)
f _H = 3 · c / (4 · l)
The length of the upper surface of the upper end pipe 3 is only required to be shorter than the length of the semi-open pipe 2, and here, the length of the semi-open pipe 2 is taken as an example. However, the present invention is not limited to this, and can be appropriately set so as to exhibit soundproofing and sound insulation effects depending on the frequency range of the sound to be controlled, the position of the sound source, the situation, the material of the wall and pipe, the thickness, and the like.
As an example, a soundproof fence corresponding to 200 to 600 Hz can be designed as follows. That is, for example, the soundproof fence 10 can be arranged at a position of 2 m from the sound source 1 with a height of 3 m. Further, as an example, the length l ′ of the upper end tube 2 is 0.1429 m, the length l of the half-open tube 3 is 0.4288 m, the inner diameter d of each half-open tube 2 and the upper end tube 3 is 0.16 m, The thickness of each semi-open tube 2 can be 0.04 m. In this case, the length from the wall portion 4 obtained by adding the thickness of the wall portion 4 and the length l of the semi-open tube, that is, the total thickness w of the soundproof rod 10 is 0.4688 m.
As shown in FIGS. 2 and 3, a large number of the semi-open tubes 2 are arranged on the side surface of the wall portion 4 of the soundproof fence 10, and the sound source 1 side of each of the semi-open tubes 2 and the upper end tube 3 is open. The part in contact with the wall 4 is closed.
Each semi-open tube 2 on the side surface of the wall 4 creates a standing wave inside and always has nodes and bellies. This standing wave is common to many semi-open pipes 2 arranged in the vertical and horizontal directions on the side wall 4 of the soundproofing wall 10, and a constant sound pressure distribution is distributed over the entire side surface of the wall 4 of the soundproofing wall 10. Bring. Further, inside each half-open tube 2, there is a portion where the sound pressure distribution is minimized by the standing wave. This standing wave makes the sound pressure distribution along the side surface of the wall portion 4 of the soundproof rod 10 uniform, and the sound pressure distribution by the standing wave is continuously generated up to the position of the front surface of the upper end tube 3. At the upper end of the soundproof enclosure 10, the sound pressure distribution of the upper end pipe 3 is so-called “extrusion”, and at the upper end of the soundproof enclosure 10, there is a portion with a low sound pressure. In the upper end pipe 3 arranged at the upper end part, a standing wave is created in the inside thereof as in each of the semi-open pipes 2, but by making the length of the upper end pipe 3 shorter than that of the semi-open pipe 2, The sound pressure distribution at the front surface position of the upper end portion of 10 is minimized. The distance in the horizontal direction from the side surface of the soundproof rod 10 of the minimal portion is that of the minimal sound pressure portion generated in the opening of the upper end tube 3 and inside the upper end tube 3 by the effect of the upper end tube 3 on the side surface. Match.
As described above, the sound pressure distribution at the front surface position of the upper end portion of the soundproofing cage 10 is minimized on the side surface of the wall 4 of the soundproofing cage 10 in order to make the sound pressure distribution uniform due to standing waves. Due to the uniform and minimal sound pressure distribution, the minimum sound pressure distribution near the upper end is maintained in a wide frequency range, so that sound emission from the upper end, which is regarded as a pseudo sound source, is reduced, resulting in good noise. A reduction effect is obtained.
FIG. 4 is an explanatory diagram of the sound pressure distribution.
As shown in the figure, the minimum sound pressure portion a is distributed with respect to the noise from the sound source 1. Further, in the vicinity of the pseudo sound source portion b of the upper end tube 3, the sound pressure is always reduced by the minimal sound pressure portion a, so that the diffracted sound is reduced.
FIG. 5 is an explanatory view of a model experiment of the soundproofing cage 10 according to the present invention.
The sound from the sound source 1 is measured at the sound receiving point 11 through the soundproofing cage 10. In the experiment, the distance from the soundproof rod 10 to the sound source 1 was Xs, and the distance to the sound receiving point 11 was Xr.
FIGS. 6 and 7 show comparative explanatory views (1) and (2) of insertion loss with a single wall, respectively.
6 and 7 show the results of an experiment using a model as shown in FIG. 5 on a 1/10 scale of actual dimensions. Moreover, the soundproof fence 10 was designed about the 200-600Hz sound insulation wall as an example. In FIG. 6, the experiment was conducted with the distances from the soundproof rod 10 to the sound source 1 and the sound receiving point 11 being Xs = 2m and Xr = 2m, respectively. In FIG. 7, the experiment was performed with the distances from the soundproof rod 10 to the sound source 1 and the sound receiving point 11 being Xs = 4 m and Xr = 4 m, respectively. Moreover, in both FIG.6 and FIG.7, the experiment was conducted by setting the height of the soundproof rod 10 to 3 m and the thickness w to 0.4688 m. The thickness of the soundproof rod 10 is increased for clarity of comparison, and is not limited to this thickness.
6 and 7, the horizontal axis represents the actual frequency, and here, as an example, the model shows a range of 100 to 1000 Hz. The vertical axis represents the insertion loss, and shows the sound pressure level when the soundproofing rod 10 is raised, that is, how many decibels the sound pressure is lowered, based on the sound pressure level when the soundproofing rod 10 is not provided. Is.
In FIGS. 6 and 7, the dotted line represents the result for the soundproofing fence with a normal single wall, and the solid line represents the result for the soundproofing fence 10 according to the present invention. As can be seen from the figure, both FIG. 6 and FIG. 7 show clearly good results at, for example, 100 Hz or higher, particularly at the corresponding sound insulation frequencies of 200 to 600 Hz or 300 Hz or higher.
FIG. 8 shows an explanatory diagram of the second embodiment of the present invention.
FIG. 8 (A) shows a case where the upper end pipe 3 in the soundproof rod 10 in FIG. 8B shows a case where the bottom surface of the upper end tube 3 and the upper surface of the semi-open tube 2 in FIG. 8A are shared.
FIG. 9 shows an overall configuration diagram of the third embodiment of the present invention.
In this example, the semi-open pipe 2 and the upper end pipe 3 are provided with a plurality of small semi-open pipes 120 and 101, which are incorporated inside each pipe to divide the pipe. In addition, in this example, a small semi-open tube 102 having a length of about one third of the small semi-open tube 101 is provided above the small semi-open tube 101. The plurality of small semi-open tubes 120, 101, and 102 are shorter than the semi-open tube 2 and the upper end tube 3 and have a smaller cross-sectional area. The plurality of small and half open tubes 120, 101, and 102 can improve the performance to a higher frequency region.
FIG. 10 shows a configuration diagram of the wall end portion of the third embodiment of the present invention. This figure is an enlarged view of the wall end 100 which is the upper end of the wall 4 in FIG. In the figure, the wall end portion 100 of the wall portion 4 includes a plurality of semi-open tubes having a plurality of lengths on the sound source side and the sound receiving side. The wall end portion 100 may have a plurality of semi-open tubes on either the sound source side or the sound receiving side. On the sound source side, the semi-open tube 2 is also provided with a shorter tube arrangement. In the above-described embodiment, the tube arrangement is provided on the sound source side of the soundproofing cage. However, in this embodiment, shorter tubes are further incorporated inside these tubes.
First, the sound source side of the wall end portion 100 will be described. The wall end portion 100 includes a plurality of first small and half open tubes 101 on the sound source side, and a second small and half open tube 102 that is disposed at the end and is shorter than the first small and half open tubes 101. A plurality of first small and half open tubes 101 are incorporated in the upper end tube 3 to divide the upper end tube 3. Here, as an example, the tube lengths of the small semi-open tubes 120 and 101 are about 1/3 of the semi-open tube 2 (same as the upper end tube 3), and the tube diameter is 1 of the semi-open tube 2 and the upper end tube 3. / 2 to about 1/3. The length of the small half-open tube 102 is, for example, about 1/3 that of the small half-open tube 101 and the pipe diameter is about the same. When such a braid structure is adopted, the control frequency range is expanded. If the pipe length of the upper end pipe 3 is l ₃ , the pipe length of the small half-open pipe 102 is l _102, and l ₃ / l ₁₀₂ = n ′, the upper limit frequency of control is n 'Enlarge it twice. Note that the thickness (diameter) of the tube is set so as to control up to a frequency at which no mode is established in the diameter direction. For example, when two tubes, a 28.3 cm tube and a 9.4 cm tube, are used on the sound source side of the wall end portion 100, the frequency to be controlled is about 900 Hz. In the third embodiment, as an example, a tube having a length of 3.0 cm is further set at the top, and a tube having a length of 9.4 cm is set in two stages. As a result, the maximum frequency to be controlled can be expected to increase to a frequency at which ¼ of the wavelength of the sound matches the length of the uppermost tube (ie, about 2800 Hz).
Next, the sound receiving point side of the wall end portion 100 will be described. In the present invention, the tube arrangement is further set on the sound receiving point side of the wall end portion 100. That is, the wall end portion 100 has a third small half open tube 103 on the sound receiving side, a fourth small half open tube 104 disposed on the end side of the third small half open tube 103 and shorter than the third small half open tube 103, and an end. And a fourth small semi-open tube 104 and a fifth small semi-open tube 105 having the open end face at the same or substantially the same position and longer. As described above, when there is a tube arrangement only on the sound source side, the insertion loss (the sound pressure level value that is lower than when a soundproof box is not built) is small at a specific frequency (soundproof performance is poor) Occurs. In order to solve this problem, an acoustic tube whose length is set so that a node of a standing wave of a specific frequency sound with inferior soundproofing performance is generated behind the soundproofing cage, that is, near the end of the wall on the sound receiving point side. Array. The length of the tube on the sound receiving point side of the wall end 100 is, for example, referring to the above formula, the 12 cm one corresponds to 700 Hz, the 7 cm one corresponds to 1200 Hz, and the 14 cm one corresponds to the sound of 600 Hz. be able to.
FIG. 11 shows a comparative illustration (3) of insertion loss with a single wall. The thick solid line is the result of this soundproof fence, and the thin solid line is the result of the single wall. Note that FIG. 11 and FIG. 14 described later show the results of an experiment using a model as shown in FIG. 5 at 1/10 scale of the actual dimensions. 11 and 14, the horizontal axis represents the actual frequency, and here, as an example, the range of 100 to 1000 Hz is shown in the model. The vertical axis represents the insertion loss, and shows the sound pressure level when the soundproofing rod 10 is raised, that is, how many decibels the sound pressure is lowered, based on the sound pressure level when the soundproofing rod 10 is not provided. Is. As shown in the figure, it can be seen that clearly good results appear at, for example, 100 Hz or more, particularly at the corresponding sound insulation frequencies of about 130 to 380 Hz and about 400 Hz or more.
In FIG. 12, the block diagram of the wall edge part of the 4th Embodiment of this invention is shown.
As shown in FIG. 12A, the wall 4 has an inclined surface 41 at the upper end. The wall end portion 110 is formed so as to extend vertically or substantially vertically from the inclined surface 41. The wall end portion 110 includes, on the sound source side, a plurality of first small half-open tubes 111, and a second small half-open tube 112 that is disposed at the end portion and shorter than the first small half-open tube 111, and further includes a second A sixth small half-open tube 116 shorter than the half-open 12 can be provided. Further, on the sound receiving side, a third small half-open pipe 113, a fourth small half-open pipe 114 arranged on the end side shorter than the third small half-open pipe 113 and shorter than the third small half-open pipe 113, are arranged on the end. The fourth small semi-open tube 114 and a fifth small semi-open tube 115 having the open end face at the same or substantially the same position and longer. The wall end portion 110 is the same as the wall end portion 100, and a small half-open tube may be provided only on one of the sound receiving point side and the sound source side. FIG. 12B shows data on the length and width of each tube. These data are merely examples, and can be appropriately set according to design conditions, environment, material, size, and the like.
In the above-described third embodiment, the soundproofing cage having a shape that is nearly perpendicular to the ground is used as a basis. The fourth embodiment is a configuration of a soundproofing rod having an inclined shape in which the upper part of the soundproofing rod is partially inclined to the side opposite to the sound source (sound receiving point side). With respect to the inclined soundproof wall, the acoustic performance is improved by providing the tube arrangement on the sound source side, the sound receiving point side, and both sides as described above.
FIG. 13 shows a comparative illustration (4) of insertion loss with a single wall. The thick solid line is the result of this soundproof fence, and the dotted line is the result of the single wall. As shown in the figure, it can be seen that a particularly good result appears particularly at a corresponding sound insulation frequency of about 300 or more.
Next, FIG. 14 shows an explanatory diagram of the fifth embodiment of the present invention.
In this embodiment, a soundproof jar represented by a front view as shown in the drawing is configured by thinning a horizontal partition for each pipe. That is, in FIG. 14A, tubes having a substantially square cross section are arranged, but in FIG. 14B, vertical plates are thinned out and tubes having a rectangular cross section are arranged. Depending on the nature of the sound source, the sound field may not change much in the horizontal direction, such as road traffic noise and railway noise. In this case, even if the partition in the horizontal direction of the tube array is thinned out, the insertion loss does not change much. That is, the cross-sectional shape of each tube is a horizontally long rectangle or the like. The above-described semi-open tube 2, upper end tube 3, first to fifth small half-open tubes 101 to 105, small half-open tubes 120, and the like also have a cross-sectional shape in which the horizontal direction of the arrangement is longer than the vertical direction as appropriate. Can be.
Next, FIG. 15 shows an explanatory diagram of the sixth embodiment of the present invention.
In the above-described embodiment, small semi-open tubes 120 and 101 as shown in FIG. 15B are further provided for the semi-open tube 2 and the upper end tube 3 as shown in FIG. A small semi-open tube 102 was provided on the upper end tube 3. In the present invention, as shown in FIG. 15 (c), smaller half-open tubes 122, 106, and 107 are provided so as to divide the small half-open tubes 120, 101, and 102, respectively, and the upper small half-open tube 102 is further provided. An even smaller semi-open tube 108 was provided on the top. In addition, in this way, it is possible to provide a structure with a further number of stages step by step. Moreover, the part which forms a small semi-opened tube and has a braided structure may be configured as a whole, or may be appropriately configured as, for example, only the upper part, other than the upper part, or only the intermediate part.
The above-described embodiment is merely an example, and the number, size, length, size, position, angle, cross-sectional shape, arrangement order of each tube, various semi-open tubes / small semi-open tubes and their arrangements, The material and the like can be set as appropriate. Furthermore, the number of stages, the length, the size of the cross-sectional area, etc. of each half-open tube / small half-open tube at the wall end can be set as appropriate. Moreover, the cross-sectional shape of each semi-open tube / small semi-open tube may be an appropriate one such as a square, rectangle, rhombus, circle, ellipse, or a deformed tube thereof. Furthermore, in order to obtain a soundproofing effect in the lateral direction, a configuration similar to that of the wall end portions 100 and 110 may be provided in the lateral direction. Furthermore, the length of the upper surface of the open pipe at the upper end of the wall end 100 may be shorter than the length of the lower half-open pipe / small half-open pipe. Although the explanation is made by taking about 1/3 of the length of the small and half open pipe as an example, it is not limited to this, but the frequency range of the control target sound, the position of the sound source, the situation, the wall and pipe material, the thickness It can be set as appropriate so as to exhibit soundproofing and soundproofing effects.
In addition, when the horizontal semi-open pipe is outdoors, there may be a case where rain accumulates or dust such as dust accumulates there. Therefore, as a countermeasure for such a case in terms of maintenance, the semi-open pipe, the upper end pipe, and the like can be configured such that rainwater or the like can be smoothly discharged by slightly lowering the left side or the right side. At that time, the entire row or column of the tube array may be formed obliquely, or individual tubes may be formed obliquely. Furthermore, the inclination can be formed by adjusting the wall thickness of each pipe. Further, an acoustically transparent cover (which does not hinder sound propagation) for avoiding dust, dust, snow, rain, and wind may be provided on all or part of the soundproofing cage. As the cover, for example, a fine net or net can be used.
Industrial Applicability According to the present invention, a large number of tubes are arranged on the side surface, and the length of the tube at the upper end that becomes a pseudo sound source is shortened to create a standing wave inside the tube. The sound pressure distribution at the position can be minimized, and a good noise reduction effect can be created in a wide frequency range. Furthermore, according to the present invention, by arranging a large number of tubes that generate standing waves on the side surface of the soundproofing cage, and adjusting the length of the tube at the upper end of the soundproofing rod, the effect as the soundproofing rod is most effective. A good sound pressure distribution can be created.
In addition, according to the present invention, the semi-open pipe and / or the upper end pipe is further provided with a plurality of small half-open pipes that are incorporated inside the pipes to divide the pipes, thereby reducing the damping effect to a higher frequency. Can be enlarged. Furthermore, according to the present invention, it is possible to further improve the soundproofing performance by providing a plurality of types of pipes at the wall end of the soundproofing cage. Further, according to the present invention, the configuration can be simplified and the construction cost can be reduced by thinning out the partitions in the horizontal direction.

Claims

The wall,
A semi-open tube that is arranged on the side surface of the wall portion, one is closed by the wall portion, and the other is opened laterally to the sound source side ,
An upper end pipe shorter than the half-opened pipe, which is disposed on the upper side of the wall part, one is closed by the wall part and the other is opened laterally to the sound source side ;
In order to divide the pipe by being incorporated inside the semi-open pipe and the upper end pipe, the length is about the same as the upper end pipe or shorter than the half open pipe and the upper end pipe, A plurality of first small and half open tubes having a smaller cross-sectional area than the half open tube and the upper end tube;
A second one having a smaller cross-sectional area than the semi-open tube and the upper end tube, which is disposed at the upper part of the upper end tube, one is closed by the wall and the other is opened laterally to the sound source side. A small open tube and
The sound pressure distribution uniformly generated along the side surface of the wall portion is minimized near the sound source side front surface position of the upper end tube, and is minimized within the semi-open tube. The length of the upper end tube is shorter than the length of the semi-open tube , and the closed end surfaces of the semi-open tube and the upper end tube are defined by the wall portion,
The open end surface of the upper end tube is closer to the wall than the open end surface of the semi-open tube,
The open end face of the second small half-open pipe is a soundproof jar located closer to the wall than the open end face of the upper end pipe .

The wall,
A semi-open tube that is arranged on the side surface of the wall portion, one is closed by the wall portion, and the other is opened laterally to the sound source side,
An upper end tube shorter than the semi-open tube, which is disposed on the upper side of the wall portion, one is closed by the wall portion and the other is opened laterally to the sound source side;
With
The sound pressure distribution uniformly generated along the side surface of the wall portion is minimized near the sound source side front surface position of the upper end tube, and is minimized within the semi-open tube. The length of the upper end pipe is shorter than the length of the half open pipe, and the closed end surfaces of the half open pipe and the upper end pipe are defined by the wall portion,
The open end surface of the upper end tube is closer to the wall than the open end surface of the semi-open tube,
The wall is on the sound source side at the upper end.
A first small half-open tube, one of which is closed by the wall portion and the other is opened laterally to the sound source side;
A second small half-opened tube that is disposed at the end, one is closed by the wall, the other is laterally open to the sound source side, and shorter than the first small half-opened tube;
And
The wall portion is on the sound receiving side at the upper end.
A third small half-open pipe, one of which is closed by the wall portion and the other is opened laterally to the sound receiving side;
The fourth small half-open pipe is disposed on the end side, one side is closed by the wall, the other side is opened laterally to the sound receiving side, and the fourth short half-open pipe is shorter than the third small half-open pipe. A small open tube,
Disposed at the end, one is closed by the wall, the other is opened laterally to the sound receiving side, and the positions of the fourth small-half open tube and the open end surface are equal or substantially equal, and A fifth small half-open pipe that is longer than the fourth small half-open pipe;
Soundproof fence with.

The semi-open tubes are arranged in a plurality of rows and columns,
2. The soundproof fence according to claim 1, wherein a plurality of the upper end pipes are arranged in a row above the plurality of semi-open pipes.

The semi-open tube is
4. The soundproof enclosure according to claim 1 , wherein the soundproof enclosure is a tube having a square or rectangular cross section having a bottom face, left and right side faces, and a top face, or a circular or elliptical cross section.

When the length of the upper end tube is l ′ and l / l ′ = n, the length of the semi-open tube is l _L , the lower limit frequency of the sound to be controlled is f _L , the upper limit frequency is f _H , and the sound speed is c
f _L = c / (4 · l)
f _H = c / (4 · l ′) = n · c / (4 · l)
The soundproof jar according to any one of claims 1 to 4 , wherein

The upper end pipe is
A bottom surface wherein is shared with the upper surface of the semi-open tube, said the side surfaces equal length of semi-open tube, any one of claims 1 to 5, characterized in that a shorter top than the bottom surface Soundproof jar as described in

The length of the upper end pipe is about 1/3 of the length of the semi-open pipe, 7. The soundproof fence according to any one of claims 1 to 6 .

The semi-open tube and / or the upper end tube are:
To divide the interior into built-in tubes of each tube, a said length of the same extent as the upper end pipe or the semi-open tube and a length shorter than the upper section tube, wherein the semi-open tube and the upper end Soundproofing wall according to any one of claims 2 to 7, wherein, further comprising a small plurality of Konakara open tube cross-sectional area than the section tube.

9. The soundproofing fence according to any one of claims 2 to 8 , further comprising a small semi-open pipe shorter than the upper end pipe on the upper end pipe.

The first small half-open tube is
One side is closed by the wall portion and the other side is opened laterally to the sound source side, and is further incorporated into the first small half-open tube to further divide the tube, more than the first half-open tube A plurality of third small half-open tubes having a short and small cross-sectional area;
The second small half-opened pipe is further shorter than the second small half-opened pipe, one of which is closed by the wall portion and the other is opened laterally to the sound source side. 4 small and half open pipes
The soundproof fence according to claim 1, further comprising:

The wall portion includes an inclined surface at an upper end thereof,
The soundproof fence according to claim 2 , wherein the wall end portion is formed to extend vertically or substantially perpendicularly from the inclined surface.

The semi-open tube, the upper end tube or the small semi-open tube is:
Soundproofing wall according to any one of claims 1 to 11 horizontal direction of the array and having a longer cross-sectional shape than the vertical direction.

The semi-open tube, the upper end tube and / or the small semi-open tube are:
The soundproofing bag according to any one of claims 1 to 12 , further comprising an acoustically transparent cover on all or a part of each tube.

The semi-open tube, the upper end tube and / or the small semi-open tube are:
14. The soundproof fence according to any one of claims 1 to 13 , wherein the pipe array or individual pipes are formed to be inclined.