JP4074391B2

JP4074391B2 - Sound absorbing structure

Info

Publication number: JP4074391B2
Application number: JP30254598A
Authority: JP
Inventors: 聡山田; 好人小林; 晴信徳弘; 岐夫高柳
Original assignee: Asahi Building Wall Co Ltd
Current assignee: Asahi Building Wall Co Ltd
Priority date: 1998-10-23
Filing date: 1998-10-23
Publication date: 2008-04-09
Anticipated expiration: 2018-10-23
Also published as: JP2000132174A

Description

【０００１】
【発明の属する技術分野】
本発明は、通常の窯業製品として製造したり入手することが容易な多孔質材等からなる吸音体に所定の形状を付与して用いることで優れた吸音特性を得ることができるようにした吸音構造体に関する。
【０００２】
【従来の技術】
従来、吸音材としては、例えばガラス材やセラミックス材などからなる繊維をブランケット状もしくはブロック状にして得られる多孔質体や石膏ブロック、発泡コンクリート、断熱レンガなどのほか、無機骨材を釉薬あるいは樹脂等により接着して得られる多孔質体などが使用されている。なお、本明細書中に用いられ「多孔質体」の語は、一側面から他側面へと複雑に屈曲しながら連通する多数の微細孔（以下、「連通気孔」という。）を備え気体や液体が連続的に通過できる構造を備えたものを意味するものとする。
【０００３】
この場合、吸音材として上記多孔質体が用いられる理由は、多孔質体が備える前記連通気孔が優れた吸音特性を発現することに由来するものであるが、これら各種の多孔質体は、素材自体に規定される特定の周波数に対しての吸音特性しか保持していないとされており、有効な周波数帯域が狭いという難点があった。
【０００４】
このため、多孔質体の気孔径、気孔の形成状態や分布、かさ密度、厚み、空気の流れ抵抗値、さらにはその材質に至るまでの限定条件を素材自体に付与する手法（例えば特許第２６１３０１３号公報参照）や、背後に空気層を設けたり、複数種類の多孔質材料を複合材として用いた施工方法をとることにより、広い周波数帯域での吸音特性の向上を図る試みもすでに提案されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、限定条件を素材自体に付与する上記従来手法による場合には、素材の多孔組織に重点をおいて多孔質体の吸音特性を向上させようとするものであることから、素材自体に対する限定条件が多くなり、結果的に製造が複雑となって技術的な困難化を招いてしまう不都合があった。
【０００６】
また、背後に空気層を設けたり、複数種類の多孔質材料を複合させて行われる従来工法は、吸音特性を向上させる点では有効であるものの、素材自体の強度が充分でないことから、適宜の副資材等を用いて強度を補強する必要があるばかりでなく、空気層を設けたり副資材を介在させるために全体厚みが厚くなってしまい、施工に要する手間が増えたりコスト高になるなどの不具合があった。
【０００７】
しかも、本発明者らは、連通気孔を有してかさ比重が０．３〜１．８の範囲にある多孔質体、具体的には無機骨材を燒結した燒結多孔質体と、セラミックス繊維系多孔質ボードとのそれぞれの吸音特性につき、ＪＩＳＡ１４０５の管内法による建築材料の垂直入射吸音率測定方法に準ずる方法により１２５〜４０００Ｈｚの吸音率を空気層０ｍｍ，３０ｍｍ，５０ｍｍ，１００ｍｍの各条件のもとで調べた結果、無機骨材を燒結した燒結多孔質体では空気層０ｍｍの場合における吸音率は０．２以下と限りなく低く、また、セラミックス繊維系多孔質ボードについても吸音率は満足するものではないことが判明した。つまり、空気層を設けることなく多孔質体を駆体側に直貼りする施工方法によるときは、上記多孔質体によっては良好な吸音特性を得ることが著しく困難であることが明らかとなった。
【０００８】
本発明は従来技術にみられた上記課題に鑑み、通常の窯業製品として容易に入手したり製造することができる多孔質材等からなる吸音体を用いることにより、タイルやレンガに用いる圧着工法等により簡単、かつ、安価に施工して良好な吸音特性を得ることができる吸音構造体を提供することにその目的がある。これは、特に素材自体の具体的な形状とその配列方法とに着目して鋭意研究を重ねた結果、素材の形状を特定の形状体とし、背後に空気層や副資材を設けることなく、該形状体を一定の設置条件のもとで配列することにより、良好な吸音特性を発現し得るとの知見を得たことに由来する。なお、本明細書中の「吸音特性」とは、ＪＩＳＡ１４０９に相当する残響室法吸音率測定方法で測定したものをいう。
【０００９】
【課題を解決するための手段】
本発明は上記目的を達成すべくなされたものであり、その構成上の特徴は、それぞれの横断面形状が多角形となって相似する上側部と下側部とで該下側部を含む部位での縦断面形状が略Ｔ字形を呈してなり、上側部の横断面積が下側部の横断面積の１．０１〜２．１倍で、上側部の厚みが下側部の厚みの１．０〜０．４倍となる配分比率のもとで形成された吸音体が用いられ、該吸音体は、隣り合う上側部相互が０〜１０ｍｍの範囲内で接離する適宜間隔で複数個配列して取付け対象部材にそれぞれの底面を介して固着配置したことに構成上の特徴がある。
【００１０】
この場合、前記吸音体は、かさ比重が０．３〜１．８の多孔質材を用いるのが好ましく、さらには、該吸音体における下側部の底面には、総厚みに対し８〜７０％の深さであって、かつ、底面の総面積に対しその総開口面積が２０〜５０％となる配分比率のもとで形成された凹陥部を設けておくのが望ましい。また、該凹陥部は、適宜間隔で配列された１以上の溝部であることが好ましい。さらに、前記吸音体は、かさ比重が０．３〜１．１であるセラミックス繊維系多孔質ボードやかさ比重が１．４〜１．８で気孔率が１０〜３０％となるように無機質粒子を燒結させてなる無機多孔質体により形成されているものを好適に用いることができる。
【００１１】
【００１２】
【発明の実施の形態】
図１は本発明に用いられる吸音体の一例についての平面図であり、図２は図１におけるＡ−Ａ線矢視方向での縦断面図をそれぞれ示す。
【００１３】
これらの図によれば、吸音体１２は、それぞれの横断面形状が正方形となって相似する上側部１３と下側部１５とで該下側部１５を含む部位での縦断面形状が略Ｔ字形を呈し、そのかさ比重が０．３〜１．８である多孔質材により形成されている。
【００１４】
この場合、吸音体１２は、図３に示すようにその総厚みｔに対し８〜７０％の深さであって、かつ、底面１６の総面積に対しその総開口面積が２０〜５０％となる配分比率のもとで、下側部１５の底面１６に例えば３条など、等間隔を含む適宜の間隔で配設された複数条の溝部１８などからなる凹陥部１７を設けておくのが好ましい。
【００１５】
また、吸音体１２としては、かさ比重が０．３〜１．１であるセラミックス繊維系多孔質ボード（ロックウールを含む）により形成されたものや、かさ比重が１．４〜１．８で気孔率が１０〜３０％となるように無機質粒子を燒結させてなる無機多孔質材により形成されたものを好適に用いることができる。
【００１６】
しかも、該吸音体１２は、上側部１３の横断面積（ａ×ｂ）が下側部１５の横断面積（ａ′×ｂ′）の１．０１〜２．１倍で、上側部１３の厚み（ｔ1 ）が下側部１５の厚み（ｔ2 ）の１．０〜０．４倍となる配分比率のもとで形成されいる。
【００１７】
これを具体的に示せば、上側部１３の一辺（ａ）と他辺（ｂ）との長さがそれぞれ１００ｍｍとするとき、その横断面積（ａ×ｂ）は１００００ｍｍ2 となる。これに対し、下側部の一辺（ａ′）と他辺（ｂ′）との長さがそれぞれ９０ｍｍとするとき、その横断面積（ａ′×ｂ′）は８１００ｍｍ2 となる。つまり、この場合における上側部１３と下側部１５とのそれぞれの横断面積は、上側部１３が下側部の１．２３倍となった配分比率となる。
【００１８】
また、上側部１３の厚み（ｔ1 ）と下側部１５の厚み（ｔ2 ）との関係については、上側部１３の厚み（ｔ1 ）が５ｍｍで、下側部１５の厚み（ｔ2 ）が５ｍｍであるとするとき、上側部１３と下側部１５とは等倍の配分比率となることになる。
【００１９】
さらに、吸音体１２は、図４に示すようにそれぞれの横断面形状が正三角形となって相似する上側部１３と下側部１５とで該下側部１５を含む部位での縦断面形状が略Ｔ字形を呈し、そのかさ比重が０．３〜１．８である多孔質材からなる吸音体１２により形成することもできる。また、吸音体１２を構成している上側部１３と下側部１５とは、図示は省略してあるが、それぞれの横断面形状が長方形や二等辺三角形や直角三角形のほか、正五角形などの多角形形状を呈しているものであってもよい。なお、本発明において上側部１３と下側部１５との横断面形状を適宜の多角形とする理由は、多数の吸音体１２を配列させた際に、隣り合う相互間に均一な空隙を容易に確保できるので、施工する際の作業性を高め、外観デザイン面からも好ましいものとすることができるからである。
【００２０】
一方、図５（イ），（ロ）は、上記吸音体１２を用いて構成される本発明に係る吸音構造体の一例を示すものであり、そのうち（イ）は、平面形状が正四角形を呈する吸音体１２を４個組み合わせた部位についての部分平面図を、（ロ）は、（イ）におけるＢ−Ｂ線矢視方向での断面図をそれぞれ示すものであり、以下に吸音体１２の作用とともに説明する。
【００２１】
すなわち、本発明に係る吸音構造体は、複数個の同一規格もしくは規格を異にする吸音体１２を隣り合う上側部１３の側縁１４相互が０〜１０ｍｍの範囲内で接離する適宜間隔で配列することにより、駆体等からなる取付け対象部材２１にそれぞれの底面１６を介して固着配置することにより形成される。この場合、より好ましくは、隣り合う上側部１３の側縁１４相互を１〜１０ｍｍの範囲で等間隔に離間させることにより、吸音体１２，１２相互間に凸状空間部２２を確保した状態のもとで配列するのが望ましい。
【００２２】
取付け対象部材２１への吸音体１２の固着手段は、例えばタイル貼りやレンガ積みなどで通常用いられている公知の圧着工法が省力化やコスト低減の見地からは望ましいが、これ以外にも所望に応じた適宜の固定手段を用いて固着することもできる。
【００２３】
また、吸音体１２としては、一辺の長さが１００〜３００ｍｍで、その総厚みｔが１０〜３０ｍｍのものを好適に用いることができる。その理由は、一辺の長さが１００ｍｍを下回ると施工に手間がかかり、３００ｍｍを越えると重量が増して施工上の作業性が悪くなるばかりでなく、凸状空間部２２を調整することによる吸音特性の向上が期待できなくなるからである。また、総厚みｔが１０ｍｍを下回ると上側部１３の庇状の突出部位の強度が不足し、３０ｍｍを越えると全体が嵩張るばかりでなく重量も増して施工する上での作業性が悪くなるからである。
【００２４】
このとき、隣り合う上側部１３の側縁１４相互を１〜１０ｍｍの範囲で等間隔に離間させるのが好ましい理由は、吸音特性上有効な範囲内で吸音体体１２，１２相互間に確保される凸状空間部２２の容量をできるだけ大きなものとする必要があるためである。
【００２５】
また、上側部１３の横断面積が下側部１５の横断面積の１．０１〜２．１倍で、上側部１３の厚みｔ1 が下側部１５の厚みｔ2 の１．０〜０．４倍となる配分比率のもとで吸音体１２が形成されなければならないのは、複数の吸音体１２を配列した際に目地部をできる限り小さくとりながらも吸音体１２，１２相互間に凸状空間部２２を確保する必要があるためである。
【００２６】
この場合、吸音体１２における上側部１３の横断面積が下側部１５の横断面積の１．０１倍よりも小さい場合には、吸音特性の向上に寄与し得る凸状空間部２２が得られなくなり、２．１倍よりも大きくなると、上側部１３の庇状の突出部位が大きくなり過ぎてカケや割れが発生しやすくなって実用性に劣ることになる。このため、上側部１３の横断面積は、下側部１５の横断面積の１．０１〜２．１倍の範囲内で適宜設定された吸音体１２を用いる必要がある。
【００２７】
また、上側部１３の厚み（ｔ1 ）が下側部１５の厚み（ｔ2 ）の１．０倍を越えてしまうと凸状空間部２２の調整による吸音特性の向上が期待できず、良好な吸音特性を得ることが困難になり、上側部１３の厚み（ｔ1 ）が下側部１５の厚み（ｔ2 ）の０．４倍より小さくなると上側部１３の庇状の突出部位が薄くなり過ぎて十分な強度を確保することができず、カケや割れが発生しやすくなって実用性に欠けることになるからである。
【００２８】
さらに、本発明における吸音体１２として、下側部１５の底面１６に吸音体１２の総厚みｔに対し８〜７０％の深さであって、かつ、底面１６の総面積に対しその総開口面積が２０〜５０％となる配分比率のもとで、例えば等間隔に配列された複数条の溝部１８などからなる凹陥部１７を有するものを用いる場合には、施工の際に取付け対象部材２１との間に空気層に匹敵する閉空間を確保できることになる。
【００２９】
この場合、凹陥部１７は、底面１６の総面積に対しその総開口面積が２０％を下回ったり、溝部１７の深さが吸音体１２の総厚みに対し８％を下回るときは、空気層として機能し得る十分な容積の閉空間を確保できないことから、吸音特性の向上を期待することができない。また、底面１６の総面積に対しその総開口面積が５０％を越えたり、溝部１７の深さが吸音体１２の総厚みｔに対し７０％を越えると、吸音体１２に対し必要にして十分な強度を付与できなくなる。なお、凹陥部１７は、上記条件を満たしていさえすれば、適宜本数の溝部１８により形成したり、穴部により形成するなど、取付け対象部材２１との間に空間部を確保できさえするものであるならばその具体的な形状は問わない。また、製造上支障を来さない範囲で最大容積を確保し得るようにして凹陥部１７を設けるのが好ましい。
【００３０】
【実施例】
本発明の実施例につき、比較例との対比のもとで、以下に詳説する。すなわち、本発明に用いられる吸音体１２としては、樹脂、耐火物、耐火レンガ等の有機質あるいは無機質の素材に限定されることなく所定の吸音効果が得られる適宜の吸音性材料を用い得るが、本発明の実施例においては、セラミックス骨材に結合剤を添加して構成した無機多孔質体と、ガラス繊維の多孔質体として代表されるロックウールとを用いた。この場合、無機多孔質体は、珪石、陶磁器、シャモット等のセラミックス骨材を使用することができる。本発明の実施例においては、シリカ（ＳｉＯ2 ）８０％，アルミナ（Ａｌ2 Ｏ3 ）１７％の化学組成からなるセラミックス粒子を０．２〜２ｍｍに粉砕した骨材に長石、珪石、粘土等を配合して１３００℃以上の温度で溶融し、骨材の結合力をもたせるように調整した窯業原料粉末を５％添加して成形し、１３００℃の温度で焼成して得られた無機多孔質体が用いられている。なお、このようにして得られた上記無機多孔質体は、曲げ強度が１３０〜１５０Ｋｇ／ｃm2で、かさ比重が１．５〜１．７、気孔率が１５〜３０％の特性を備えていた。また、ガラス繊維の多孔質体としては、かさ比重が０．３〜０．５であるロックウールを使用した。
【００３１】
（比較例）上記条件を満たす２００ｍｍ（縦）×２００ｍｍ（横）×２５ｍｍ（総厚みｔ）の直方体形状を呈する無機多孔質体を直径が１００ｍｍの円となるように切断加工し、空気層０ｍｍの条件のもとで垂直入射吸音率を測定したところ、図６に示す結果が得られた。同図によれば、単純な立体形状を呈する無機多孔質体を空気層０ｍｍの条件のもとで用いる場合には、垂直入射吸音率が著しく低下することが判明し、より信頼度が高いとされる後述の残響室法による吸音率によっても同等の結果を示すものと推測される。なお、ロックウールを使用して同様の測定を行った際の垂直入射吸音率も満足すべき数値からは程遠い結果しか得られなかった。
【００３２】
（実施例１）上記ロックウールを１５０ｍｍ（縦）×１５０ｍｍ（横）×２４ｍｍ（総厚みｔ）の形状にカットし、さらに上側部（１５０ｍｍ）の横断面積が下側部（１３０ｍｍ）の横断面積の１．３３倍、上側部の厚みｔ1 が下側部ｔ2 の厚みの１．０倍となるように加工して複数個の吸音体を形成した。これらの吸音体を隣り合う上側部相互が密接するようにして配列し、残響室法による吸音率を測定したところ、図７に示す結果を得た。
【００３３】
（実施例２）実施例１で用いた吸音体を上側部相互が３ｍｍの等間隔で離間するように配列し、同様に残響室法による吸音率を測定したところ、図８に示す結果を得た。
【００３４】
（実施例３）実施例１で用いた吸音体を上側部相互が６ｍｍの等間隔で離間するように配列し、同様に残響室法による吸音率を測定したところ、図９に示す結果を得た。
【００３５】
（実施例４）上記ロックウールを１５０ｍｍ（縦）×１５０ｍｍ（横）×２４ｍｍ（総厚みｔ）の形状にカットし、さらに上側部（１５０ｍｍ）の横断面積が下側部（１４０ｍｍ）の横断面積の１．１５倍、上側部の厚みｔ1 が下側部の厚みｔ2 の１．０倍となるように加工して複数個の吸音体を形成した。これらの吸音体を隣り合う上側部相互が３ｍｍの等間隔で離間するように配列し、同様に残響室法による吸音率を測定したところ、図１０に示す結果を得た。
【００３６】
（実施例５）実施例４で用いた吸音体を隣り合う上側部相互が６ｍｍの等間隔で離間するように配列し、同様に残響室法による吸音率を測定したところ、図１１に示す結果を得た。
【００３７】
すなわち、ロックウールからなる吸音体を用いて行われた実施例１〜５の測定結果のうち、上側部相互を密接するように配置した実施例１によっても吸音特性が向上することが確認され、さらに、上側部相互を離間させた実施例２〜５による場合には、より大きく離間させることでその吸音特性をさらに向上させ得ることが判明した。
【００３８】
（実施例６）上記無機多孔質体を１５０ｍｍ（縦）×１５０ｍｍ（横）×２４ｍｍ（総厚みｔ）であって、上側部（１５０ｍｍ）の横断面積が下側部（１３０ｍｍ）の横断面積の１．３３倍、上側部の厚みｔ1 が下側部の厚みｔ2 の１．０倍となるように成形し、これを焼成して複数個の吸音体を形成した。これらの吸音体を隣り合う上側部相互が３ｍｍの等間隔で離間するように配列し、残響室法による吸音率を測定したところ、図１２に示す結果を得た。
【００３９】
（実施例７）上記無機多孔質体を２００ｍｍ（縦）×２００ｍｍ（横）×２４ｍｍ（総厚みｔ）であって、上側部（２００ｍｍ）の横断面積が下側部（１９０ｍｍ）の横断面積の１．１１倍、上側部の厚みｔ1 が下側部の厚みｔ2 の１．０倍となるように成形し、これを焼成して複数個の吸音体を形成した。これらの吸音体を隣り合う上側部相互が３ｍｍの等間隔で離間するように配列し、残響室法による吸音率を測定したところ、図１３に示す結果を得た。
【００４０】
すなわち、無機多孔質体からなる吸音体を用いて行われた実施例６，７の測定結果からも明らかなように、該吸音体を隣り合う上側部相互間に間隔をおいて配置することにより、吸音特性が向上することが確認された。
【００４１】
（実施例８）上記無機多孔質体を２００ｍｍ（縦）×２００ｍｍ（横）×２３ｍｍ（総厚みｔ）であって、上側部（２００ｍｍ）の横断面積が下側部（１９０ｍｍ）の横断面積の１．１１倍で、上側部（１１ｍｍ）の厚みｔ1 が下側部（１２ｍｍ）の厚みｔ2 の０．９２倍であって、底部に深さが２ｍｍ、つまり総厚み（２３ｍｍ）の８．６％で、総開口面積が２６％（１０ｍｍ幅の溝を５条）を占める凹陥部を形成して複数個の吸音体を形成した。これらの吸音体を隣り合う上側部相互が３ｍｍの等間隔で離間するように配列し、残響室法による吸音率を測定したところ、図１４に示す結果を得た。
【００４２】
（実施例９）上記無機多孔質体を２００ｍｍ（縦）×２００ｍｍ（横）×２３ｍｍ（総厚みｔ）であって、上側部（２００ｍｍ）の横断面積が下側部（１９０ｍｍ）の横断面積の１．１１倍で、上側部（１１ｍｍ）の厚みｔ1 が下側部（１２ｍｍ）の厚みｔ2 の０．９２倍であって、底部に深さが８ｍｍ、つまり総厚み（２３ｍｍ）の３４．７％で、総開口面積が底面の面積の２６％（１０ｍｍ幅の溝を５条）を占める凹陥部を形成して複数個の吸音体を形成した。これらの吸音体を隣り合う上側部相互が３ｍｍの等間隔で離間するように配列し、残響室法による吸音率を測定したところ、図１５に示す結果を得た。
【００４３】
（実施例１０）上記無機多孔質体を２００ｍｍ（縦）×２００ｍｍ（横）×２５ｍｍ（総厚みｔ）であって、上側部（２００ｍｍ）の横断面積が下側部（１９０ｍｍ）の横断面積の１．１１倍で、上側部（１１ｍｍ）の厚みｔ1 が下側部（１４ｍｍ）の厚みｔ2 の０．７８倍であって、底部に深さが８ｍｍ、つまり総厚み（２５ｍｍ）の３２％で、総開口面積が底面の総面積の４２．８％（１６ｍｍ幅の溝を５条）を占める凹陥部を形成して複数個の吸音体を形成した。これらの吸音体を隣り合う上側部相互が３ｍｍの等間隔で離間するように配列し、残響室法による吸音率を測定したところ、図１６に示す結果を得た。
【００４４】
（実施例１１）上記無機多孔質体を２００ｍｍ（縦）×２００ｍｍ（横）×２５ｍｍ（総厚みｔ）であって、上側部（２００ｍｍ）の横断面積が下側部（１９０ｍｍ）の横断面積の１．１１倍で、上側部（１１ｍｍ）の厚みｔ1 が下側部（１４ｍｍ）の厚みｔ2 の０．７８倍であって、底部に深さが１２ｍｍ、つまり総厚み（２５ｍｍ）の４８％で、総開口面積が底面の総面積の４２．８％（１６ｍｍ幅の溝を５条）を占める凹陥部を形成して複数個の吸音体を形成した。これらの吸音体を実施例１０と同様に配列し、残響室法による吸音率を測定したところ、図１７に示す結果を得た。
【００４５】
（実施例１２）上記無機多孔質体を２００ｍｍ（縦）×２００ｍｍ（横）×２５ｍｍ（総厚みｔ）であって、上側部（２００ｍｍ）の横断面積が下側部（１９０ｍｍ）の横断面積の１．１１倍で、上側部（１１ｍｍ）の厚みｔ1 が下側部（１４ｍｍ）の厚みｔ2 の０．７８倍であって、底部に深さが１４ｍｍ、つまり総厚み（２５ｍｍ）の５６％で、総開口面積が底面の総面積の４２．８％（１６ｍｍ幅の溝を５条）を占める凹陥部を形成して複数個の吸音体を形成した。これらの吸音体を実施例１０と同様に配列し、残響室法による吸音率を測定したところ、図１８に示す結果を得た。
【００４６】
（実施例１３）上記無機多孔質体を２００ｍｍ（縦）×２００ｍｍ（横）×３０ｍｍ（総厚みｔ）であって、上側部（２００ｍｍ）の横断面積が下側部（１９０ｍｍ）の横断面積の１．１１倍で、上側部（１０ｍｍ）の厚みｔ1 が下側部（２０ｍｍ）の厚みｔ2 の０．５倍であって、底部に深さが１９ｍｍ、つまり総厚み（３０ｍｍ）の６３％で、総開口面積が底面の総面積の４２．８％（１６ｍｍ幅の溝を５条）を占める凹陥部を形成して複数個の吸音体を形成した。これらの吸音体を実施例１０と同様に配列し、残響室法による吸音率を測定したところ、図１９に示す結果を得た。
【００４７】
すなわち、底部に凹陥部を設けた無機多孔質体からなる吸音体を用いて行われた実施例８〜１３についての測定結果からも明らかなように、無機多孔質体からなる吸音体であって底部に凹陥部を設けたものを、隣り合う上側部相互間に間隔をおいて配置することにより、吸音特性がさらに向上することが確認された。しかも、凹陥部の深さと開口面積とを増大させるに従い吸音特性をより一層向上させることができることが判明した。
【００４８】
また、本発明の上記実施例が奏する効果を参酌すると、無機多孔質体からなる吸音体の底部に凹陥部を設ける場合においては、総厚みｔを例えば３０ｍｍを越える程度に大きくするとともに、実用上の強度や取扱いに支障を来さない範囲で凹陥部の深さと開口総面積とを増大させ、空気層に匹敵する閉空間の容積を可能な限り増加させることにより、吸音特性をより一層向上させ得ることを窺い知ることができる。したがって、本発明は、総厚みｔが３０ｍｍを越える無機多孔質体からなる吸音体についても適用できることになる。
【００４９】
【発明の効果】
以上述べたように本発明によれば、吸音体は、通常の窯業製品として容易に入手したり製造することができる多孔質材に特定形状を付与するして形成することができるので、技術的な困難化を招くことなく安価に提供することができる。
【００５０】
しかも、これらの吸音体は、隣り合う上側部相互が０〜１０ｍｍの範囲内で接離する適宜間隔で配列して取付け対象部材にそれぞれの底面を介して固着配置することにより、相互間に空間部を確保しながら優れた吸音特性を得ることができる。
【００５１】
また、吸音体は、空気層を設けたり、副資材を用いたりすることなく、取付け対象部材の側に直に固着して取り付けることができるので、施工を簡素化してコストの低減に寄与させることができるほか、場所等に制約を受けることなく設計上の自由度を高めて施工することができる。
【００５２】
さらに、吸音体がその下側部の底面に溝部などからなる凹陥部を備えている場合には、取付け対象部材に固着した際に空気層にも匹敵する閉空間を確保することができるので、より好ましい吸音特性を発揮させることができる。
【図面の簡単な説明】
【図１】本発明に用いられる吸音体の一例についての平面図。
【図２】図１におけるＡ−Ａ線矢視方向での縦断面図。
【図３】図１の吸音体についての変形例を図２に対応させて示す縦断面図。
【図４】本発明に用いられる吸音体の他例についての平面図。
【図５】本発明に係る吸音構造体の一例を示すものであり、そのうちの（イ）は吸音体を４個組み合わせた部位についての部分平面図を、（ロ）は（イ）におけるＢ−Ｂ線矢視方向での縦断面図をそれぞれ示す。
【図６】比較例についての吸音特性を示すグラフ図。
【図７】実施例１についての吸音特性を示すグラフ図。
【図８】実施例２についての吸音特性を示すグラフ図。
【図９】実施例３についての吸音特性を示すグラフ図。
【図１０】実施例４についての吸音特性を示すグラフ図。
【図１１】実施例５についての吸音特性を示すグラフ図。
【図１２】実施例６についての吸音特性を示すグラフ図。
【図１３】実施例７についての吸音特性を示すグラフ図。
【図１４】実施例８についての吸音特性を示すグラフ図。
【図１５】実施例９についての吸音特性を示すグラフ図。
【図１６】実施例１０についての吸音特性を示すグラフ図。
【図１７】実施例１１についての吸音特性を示すグラフ図。
【図１８】実施例１２についての吸音特性を示すグラフ図。
【図１９】実施例１３についての吸音特性を示すグラフ図。
【符号の説明】
１２吸音体
１３上側部
１４側縁
１５下側部
１６底面
１７凹陥部[0001]
BACKGROUND OF THE INVENTION
The present invention provides a predetermined shape to a sound absorber made of a porous material or the like that is easy to manufacture or obtain as a normal ceramic product. By using So that you can get excellent sound absorption Sucking It relates to sound structures.
[0002]
[Prior art]
Conventionally, as a sound-absorbing material, for example, a porous material, a gypsum block, foamed concrete, a heat insulating brick, etc. obtained by making fibers made of glass material or ceramic material into a blanket shape or block shape, inorganic aggregates as glaze or resin For example, a porous body obtained by bonding with the like is used. Note that the term “porous body” used in the present specification includes a large number of micropores (hereinafter referred to as “continuous vent holes”) that are intricately bent from one side surface to the other side surface and are connected to gas or It shall mean the thing provided with the structure which a liquid can pass continuously.
[0003]
In this case, the reason why the porous body is used as the sound absorbing material is derived from the fact that the continuous air holes provided in the porous body exhibit excellent sound absorbing properties. It is said that only the sound absorption characteristic with respect to a specific frequency defined by itself is held, and there is a problem that an effective frequency band is narrow.
[0004]
For this reason, a pore diameter of a porous body, a formation state and distribution of pores, a bulk density, a thickness, an air flow resistance value, and a method of giving a limiting condition to the material itself (for example, Japanese Patent No. 2613013) There are already attempts to improve the sound absorption characteristics in a wide frequency band by providing an air layer in the back or a construction method using multiple types of porous materials as composite materials. Yes.
[0005]
[Problems to be solved by the invention]
However, in the case of using the above-described conventional method in which the limiting condition is given to the material itself, the limiting condition for the material itself is intended to improve the sound absorption characteristics of the porous body with emphasis on the porous structure of the material. As a result, there is a disadvantage that manufacturing becomes complicated and technical difficulties are caused.
[0006]
In addition, although the conventional method, which is performed by providing an air layer behind or combining multiple types of porous materials, is effective in improving the sound absorption characteristics, the strength of the material itself is not sufficient, Not only is it necessary to reinforce the strength using secondary materials, etc., but the overall thickness increases due to the provision of an air layer and the inclusion of secondary materials, which increases the labor and cost required for construction. There was a bug.
[0007]
Moreover, the present inventors have a porous body having continuous air holes and a bulk specific gravity in the range of 0.3 to 1.8, specifically, a sintered porous body obtained by sintering inorganic aggregate, and ceramic fibers. The sound absorption characteristics of each porous board are measured in accordance with the method for measuring the normal incident sound absorption coefficient of building materials according to the JIS A1405 in-pipe method, and the sound absorption coefficient of 125 to 4000 Hz is set to each condition of 0 mm, 30 mm, 50 mm and 100 mm in the air layer. As a result of the investigation, the sintered porous body sintered with the inorganic aggregate has an extremely low sound absorption coefficient of 0.2 or less when the air layer is 0 mm, and the sound absorption coefficient of the ceramic fiber-based porous board is also low. It turns out that it is not satisfactory. In other words, it was revealed that it was extremely difficult to obtain good sound absorption characteristics depending on the porous body when the construction method was performed by directly attaching the porous body to the driver side without providing an air layer.
[0008]
In view of the above-mentioned problems found in the prior art, the present invention uses a sound absorber made of a porous material or the like that can be easily obtained or manufactured as a normal ceramic product, and the like, for example, a crimping method used for tiles and bricks. Can be installed easily and inexpensively to obtain good sound absorption characteristics. Suck The purpose is to provide a sound structure. This is because, as a result of earnest research, focusing on the specific shape of the material itself and the arrangement method thereof, the shape of the material is made into a specific shape body, without providing an air layer or auxiliary material behind, It originates in having acquired the knowledge that a favorable sound absorption characteristic can be expressed by arranging a shape body on fixed installation conditions. In addition, the “sound absorption characteristic” in the present specification means a value measured by a reverberation chamber method sound absorption rate measurement method corresponding to JIS A1409.
[0009]
[Means for Solving the Problems]
The present invention has been made to achieve the above object. Structure The feature of the growth is that the cross-sectional shape of each of the upper and lower parts resembles a polygonal shape, and the vertical cross-sectional shape at the portion including the lower side part is substantially T-shaped. The distribution ratio is such that the cross-sectional area of the upper part is 1.01 to 2.1 times the cross-sectional area of the lower part and the thickness of the upper part is 1.0 to 0.4 times the thickness of the lower part. A plurality of sound absorbers are arranged at appropriate intervals so that adjacent upper parts come in contact with each other within a range of 0 to 10 mm, and are attached to a member to be attached via each bottom surface. Secure placement To do Configuration features is there.
[0010]
In this case, it is preferable to use a porous material having a bulk specific gravity of 0.3 to 1.8 as the sound absorber, and further, the bottom surface of the lower portion of the sound absorber has a thickness of 8 to 70 with respect to the total thickness. It is desirable to provide recesses formed at a distribution ratio of 20% to 50% of the total opening area with respect to the total area of the bottom surface. Moreover, it is preferable that this recessed part is one or more groove parts arranged at appropriate intervals. Further, the sound absorber is made of a ceramic fiber-based porous board having a bulk specific gravity of 0.3 to 1.1 or an inorganic particle so that the bulk specific gravity is 1.4 to 1.8 and the porosity is 10 to 30%. What is formed with the inorganic porous body formed by sintering can be used suitably.
[0011]
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows the present invention. Sound absorber used for FIG. 2 is a longitudinal sectional view taken along line AA in FIG. 1.
[0013]
According to these figures, sound absorption Body 12 Each of the upper side portion 13 and the lower side portion 15 that are similar to each other in a square cross-sectional shape has a substantially T-shaped vertical cross-sectional shape at a portion including the lower side portion 15 and has a bulk specific gravity of 0. Porous that is 3-1.8 Material Is formed.
[0014]
In this case, as shown in FIG. 3, the sound absorber 12 is 8 to 70% deep with respect to the total thickness t, and the total opening area is 20 to 50% with respect to the total area of the bottom surface 16. Under the distribution ratio, the bottom surface 16 of the lower side portion 15 is provided with concave portions 17 composed of a plurality of groove portions 18 and the like arranged at appropriate intervals including equal intervals, for example, three stripes. preferable.
[0015]
The sound absorber 12 is formed of a ceramic fiber-based porous board (including rock wool) having a bulk specific gravity of 0.3 to 1.1, or a bulk specific gravity of 1.4 to 1.8. What was formed with the inorganic porous material formed by sintering inorganic particles so that a porosity may become 10 to 30% can be used suitably.
[0016]
In addition, the sound absorber 12 has a cross-sectional area (a × b) of the upper side portion 13 that is 1.01 to 2.1 times a cross-sectional area (a ′ × b ′) of the lower side portion 15 and the thickness of the upper side portion 13. (T1) is formed under a distribution ratio that is 1.0 to 0.4 times the thickness (t2) of the lower portion 15.
[0017]
Specifically, when the length of one side (a) and the other side (b) of the upper portion 13 is 100 mm, the cross-sectional area (a × b) is 10,000 mm 2. On the other hand, when the length of one side (a ′) and the other side (b ′) of the lower side portion is 90 mm, the cross-sectional area (a ′ × b ′) is 8100 mm 2. That is, the cross-sectional area of each of the upper part 13 and the lower part 15 in this case is a distribution ratio in which the upper part 13 is 1.23 times as large as the lower part.
[0018]
Further, regarding the relationship between the thickness (t1) of the upper portion 13 and the thickness (t2) of the lower portion 15, the thickness (t1) of the upper portion 13 is 5 mm and the thickness (t2) of the lower portion 15 is 5 mm. If there is, the upper side portion 13 and the lower side portion 15 have an equal distribution ratio.
[0019]
further, Sound absorber 12 As shown in FIG. 4, the cross-sectional shape of each of the upper side portion 13 and the lower side portion 15 which are similar to each other in an equilateral triangle is substantially T-shaped in a portion including the lower side portion 15. Further, it can be formed by the sound absorber 12 made of a porous material having a bulk specific gravity of 0.3 to 1.8. Further, although the upper side portion 13 and the lower side portion 15 constituting the sound absorber 12 are not shown, each cross-sectional shape is a rectangle, an isosceles triangle, a right triangle, a regular pentagon, or the like. It may be a polygonal shape. In the present invention, the reason why the cross-sectional shape of the upper side portion 13 and the lower side portion 15 is an appropriate polygonal shape is that many sound absorbers 12 are used. Arrange This is because when the lines are arranged, a uniform gap can be easily secured between adjacent ones, so that the workability at the time of construction can be enhanced and the appearance design can be preferable.
[0020]
On the other hand, FIGS. 5A and 5B show the sound absorber 12 described above. For FIG. 2 shows an example of a sound absorbing structure according to the present invention, in which (a) is a partial plan view of a portion where four sound absorbing bodies 12 having a square shape in plan view are combined. ) Shows cross-sectional views in the direction of arrows BB in (a), respectively. 2 It explains with an effect | action.
[0021]
That is, the sound absorbing structure according to the present invention includes a plurality of sound absorbing bodies 1 having the same standard or different standards. 2 The side edges 14 of the adjacent upper side portions 13 are arranged at appropriate intervals so that the side edges 14 are in contact with each other within a range of 0 to 10 mm. It is formed by. In this case, more preferably, the side edges 14 of the adjacent upper side portions 13 are spaced apart from each other at equal intervals in the range of 1 to 10 mm, thereby securing the convex space portion 22 between the sound absorbers 12 and 12. It is desirable to arrange in the original.
[0022]
As a means for fixing the sound absorber 12 to the attachment target member 21, for example, a well-known crimping method that is usually used for tile bonding or brick stacking is desirable from the viewpoint of labor saving and cost reduction. It can also be fixed using appropriate fixing means.
[0023]
Moreover, as the sound-absorbing body 12, a length of one side of 100 to 300 mm and a total thickness t of 10 to 30 mm can be suitably used. The reason is that if the length of one side is less than 100 mm, the construction takes time, and if it exceeds 300 mm, not only the weight increases but the workability in construction deteriorates, but also the sound absorption by adjusting the convex space 22. This is because improvement in characteristics cannot be expected. In addition, when the total thickness t is less than 10 mm, the strength of the hook-like protruding portion of the upper portion 13 is insufficient, and when it exceeds 30 mm, not only the whole is bulky but also the workability is increased when the construction is increased. It is.
[0024]
At this time, the reason why it is preferable that the side edges 14 of the adjacent upper side portions 13 are spaced apart at an equal interval in the range of 1 to 10 mm is ensured between the sound absorbing bodies 12 and 12 within a range effective in sound absorption characteristics. This is because the capacity of the convex space portion 22 needs to be as large as possible.
[0025]
Further, the cross-sectional area of the upper portion 13 is 1.01 to 2.1 times the cross-sectional area of the lower portion 15, and the thickness t1 of the upper portion 13 is 1.0 to 0.4 times the thickness t2 of the lower portion 15. The sound absorbers 12 must be formed under a distribution ratio such that when the plurality of sound absorbers 12 are arranged, a convex space is provided between the sound absorbers 12 and 12 while keeping the joint portion as small as possible. This is because it is necessary to secure the portion 22.
[0026]
In this case, when the cross-sectional area of the upper side portion 13 in the sound absorber 12 is smaller than 1.01 times the cross-sectional area of the lower side portion 15, the convex space portion 22 that can contribute to the improvement of the sound absorption characteristics cannot be obtained. If it is larger than 2.1 times, the hook-like protruding portion of the upper portion 13 becomes too large, and cracks and cracks are likely to occur, resulting in poor practicality. For this reason, it is necessary to use the sound absorbing body 12 appropriately set within the range of 1.01 to 2.1 times the cross-sectional area of the lower side portion 15 as the cross-sectional area of the upper side portion 13.
[0027]
On the other hand, if the thickness (t1) of the upper side portion 13 exceeds 1.0 times the thickness (t2) of the lower side portion 15, the improvement of the sound absorption characteristics by adjusting the convex space portion 22 cannot be expected, and good sound absorption is achieved. It becomes difficult to obtain the characteristics, and if the thickness (t1) of the upper portion 13 is smaller than 0.4 times the thickness (t2) of the lower portion 15, the hook-like protruding portion of the upper portion 13 becomes too thin. This is because a sufficient strength cannot be ensured, and cracks and cracks are likely to occur, resulting in lack of practicality.
[0028]
Further, as the sound absorber 12 in the present invention, the bottom surface 16 of the lower side portion 15 has a depth of 8 to 70% with respect to the total thickness t of the sound absorber 12 and the total opening of the total area of the bottom surface 16. In the case of using, for example, a member having the recessed portions 17 composed of a plurality of groove portions 18 arranged at equal intervals under an allocation ratio of 20 to 50% in area, the attachment target member 21 is used at the time of construction. A closed space comparable to the air layer can be secured.
[0029]
In this case, when the concave portion 17 has a total opening area of less than 20% with respect to the total area of the bottom surface 16 or when the depth of the groove portion 17 is less than 8% with respect to the total thickness of the sound absorber 12, Since it is not possible to ensure a closed space having a sufficient capacity to function, it is not possible to expect an improvement in sound absorption characteristics. If the total opening area exceeds 50% of the total area of the bottom surface 16 or the depth of the groove 17 exceeds 70% of the total thickness t of the sound absorber 12, it is necessary and sufficient for the sound absorber 12. It will not be possible to impart a sufficient strength. In addition, as long as the above-mentioned conditions are satisfied, the recessed portion 17 can be formed with a suitable number of groove portions 18 or formed with a hole portion so that a space portion can be secured between the mounting target member 21 and the like. If there is, the specific shape does not matter. Moreover, it is preferable to provide the recessed part 17 so that the maximum volume can be ensured in the range which does not interfere with manufacture.
[0030]
【Example】
Examples of the present invention will be described in detail below in comparison with comparative examples. That is, the sound absorber 12 used in the present invention is not limited to organic or inorganic materials such as resins, refractories, and refractory bricks, but may be any appropriate sound absorbing material that can obtain a predetermined sound absorption effect. In the Example of this invention, the inorganic porous body comprised by adding a binder to ceramic aggregate and the rock wool represented by the porous body of glass fiber were used. In this case, as the inorganic porous material, ceramic aggregates such as silica, ceramics and chamotte can be used. In an embodiment of the present invention, feldspar, quartzite, clay, etc. are blended into an aggregate obtained by grinding ceramic particles having a chemical composition of 80% silica (SiO2) and 17% alumina (Al2 O3) to 0.2 to 2 mm. An inorganic porous body obtained by adding 5% ceramic raw material powder that has been melted at a temperature of 1300 ° C. or higher and adjusted to give an aggregate binding force, and fired at a temperature of 1300 ° C. is used. It has been. The inorganic porous material thus obtained had characteristics such that the bending strength was 130 to 150 kg / cm2, the bulk specific gravity was 1.5 to 1.7, and the porosity was 15 to 30%. . Moreover, the rock wool whose bulk specific gravity is 0.3-0.5 was used as the porous body of glass fiber.
[0031]
(Comparative Example) An inorganic porous body having a rectangular parallelepiped shape of 200 mm (vertical) × 200 mm (horizontal) × 25 mm (total thickness t) that satisfies the above conditions is cut into a circle with a diameter of 100 mm, and an air layer is 0 mm. When the normal incidence sound absorption coefficient was measured under the above conditions, the results shown in FIG. 6 were obtained. According to the figure, when an inorganic porous body having a simple three-dimensional shape is used under the condition of an air layer of 0 mm, it is found that the normal incident sound absorption coefficient is remarkably lowered, and the reliability is higher. It is presumed that the same result is obtained by the sound absorption coefficient according to the reverberation chamber method described later. In addition, only the result far from the numerical value which should satisfy the normal incident sound absorption rate when performing the same measurement using rock wool was obtained.
[0032]
(Example 1) The rock wool is cut into a shape of 150 mm (length) x 150 mm (width) x 24 mm (total thickness t), and the cross-sectional area of the upper side (150 mm) is the cross-sectional area of the lower side (130 mm) A plurality of sound absorptions by processing so that the thickness t1 of the upper part is 1.03 times the thickness of the lower part t2. Body Formed. These sound absorbers were arranged so that the adjacent upper portions were in close contact with each other, and the sound absorption rate was measured by the reverberation chamber method, and the result shown in FIG. 7 was obtained.
[0033]
(Example 2) Sound absorption used in Example 1 Body When the upper side portions were arranged so as to be spaced apart at equal intervals of 3 mm and the sound absorption rate was measured by the reverberation chamber method in the same manner, the result shown in FIG. 8 was obtained.
[0034]
(Example 3) Sound absorption used in Example 1 Body When the upper side portions were arranged so as to be spaced apart at equal intervals of 6 mm and the sound absorption rate was measured by the reverberation chamber method in the same manner, the result shown in FIG. 9 was obtained.
[0035]
(Example 4) The rock wool was cut into a shape of 150 mm (length) x 150 mm (width) x 24 mm (total thickness t), and the cross-sectional area of the upper side (150 mm) was the cross-sectional area of the lower side (140 mm) Is processed so that the thickness t1 of the upper part is 1.0 times the thickness t2 of the lower part, and a plurality of sound absorptions are made. Body Formed. These sound absorbers were arranged so that adjacent upper portions were spaced apart at an equal interval of 3 mm, and the sound absorption rate by the reverberation chamber method was measured in the same manner, and the result shown in FIG. 10 was obtained.
[0036]
(Example 5) Sound absorption used in Example 4 Body The adjacent upper portions were arranged so as to be spaced apart at an equal interval of 6 mm, and the sound absorption rate by the reverberation chamber method was measured in the same manner, and the result shown in FIG. 11 was obtained.
[0037]
That is, sound absorption made of rock wool Body Among the measurement results of Examples 1 to 5 that were used, it was confirmed that the sound absorption characteristics were also improved by Example 1 arranged so that the upper parts were brought into close contact with each other, and further, the upper parts were separated from each other. In the case of Examples 2 to 5, it has been found that the sound absorption characteristics can be further improved by separating them more greatly.
[0038]
(Example 6) The inorganic porous body was 150 mm (length) x 150 mm (width) x 24 mm (total thickness t), and the cross-sectional area of the upper side (150 mm) was the cross-sectional area of the lower side (130 mm) 1.33 times, formed so that the thickness t1 of the upper part is 1.0 times the thickness t2 of the lower part and fired to form a plurality of sound absorption Body Formed. These sound absorbers were arranged so that adjacent upper portions were spaced apart at an equal interval of 3 mm, and the sound absorption rate by the reverberation chamber method was measured, and the result shown in FIG. 12 was obtained.
[0039]
(Example 7) The inorganic porous body was 200 mm (length) x 200 mm (width) x 24 mm (total thickness t), and the cross-sectional area of the upper side (200 mm) was the cross-sectional area of the lower side (190 mm) 1.11 times, formed so that the thickness t1 of the upper part is 1.0 times the thickness t2 of the lower part and fired to form a plurality of sound absorption Body Formed. These sound absorbers were arranged so that adjacent upper portions were spaced apart at an equal interval of 3 mm, and the sound absorption rate was measured by the reverberation chamber method, and the result shown in FIG. 13 was obtained.
[0040]
That is, sound absorption made of inorganic porous material Body As is clear from the measurement results of Examples 6 and 7 that were used, it was confirmed that the sound absorption characteristics were improved by arranging the sound absorbers at intervals between the adjacent upper portions. .
[0041]
(Example 8) The inorganic porous body was 200 mm (length) x 200 mm (width) x 23 mm (total thickness t), and the cross-sectional area of the upper side (200 mm) was the cross-sectional area of the lower side (190 mm) 1.11 times the thickness t1 of the upper part (11 mm) is 0.92 times the thickness t2 of the lower part (12 mm) and the depth is 2 mm at the bottom, that is, 8.6 of the total thickness (23 mm). %, And a plurality of sound absorbing parts are formed by forming a recess that occupies 26% of the total opening area (5 grooves of 10 mm width). Body Formed. These sound absorbers were arranged so that adjacent upper portions were spaced apart at an equal interval of 3 mm, and the sound absorption rate was measured by the reverberation chamber method, and the result shown in FIG. 14 was obtained.
[0042]
(Example 9) The inorganic porous body was 200 mm (length) × 200 mm (width) × 23 mm (total thickness t), and the cross-sectional area of the upper side (200 mm) was the cross-sectional area of the lower side (190 mm). 1.11 times, the thickness t1 of the upper part (11 mm) is 0.92 times the thickness t2 of the lower part (12 mm), and the depth is 8 mm at the bottom, that is 34.7 of the total thickness (23 mm). %, And the total opening area is 26% of the area of the bottom surface (5 grooves of 10 mm width) are formed to form a recessed portion and a plurality of sound absorbing Body Formed. These sound absorbers were arranged so that adjacent upper portions were spaced apart at an equal interval of 3 mm, and the sound absorption rate by the reverberation chamber method was measured. The result shown in FIG. 15 was obtained.
[0043]
(Example 10) The inorganic porous body was 200 mm (length) x 200 mm (width) x 25 mm (total thickness t), and the cross-sectional area of the upper side (200 mm) was the cross-sectional area of the lower side (190 mm) 1.11 times the thickness t1 of the upper part (11 mm) is 0.78 times the thickness t2 of the lower part (14 mm) and the depth is 8 mm at the bottom, that is 32% of the total thickness (25 mm) A plurality of sound absorbing parts are formed by forming a concave portion that occupies 42.8% of the total area of the bottom surface (5 grooves of 16 mm width). Body Formed. These sound absorbers were arranged so that adjacent upper portions were spaced apart at an equal interval of 3 mm, and the sound absorption rate was measured by the reverberation chamber method, and the result shown in FIG. 16 was obtained.
[0044]
(Example 11) The inorganic porous body was 200 mm (vertical) x 200 mm (horizontal) x 25 mm (total thickness t), and the cross-sectional area of the upper part (200 mm) was the cross-sectional area of the lower part (190 mm) 1.11 times, the thickness t1 of the upper part (11 mm) is 0.78 times the thickness t2 of the lower part (14 mm) and the depth is 12 mm at the bottom, that is, 48% of the total thickness (25 mm). A plurality of sound absorbing parts are formed by forming a concave portion that occupies 42.8% of the total area of the bottom surface (5 grooves of 16 mm width). Body Formed. When these sound absorbers were arranged in the same manner as in Example 10 and the sound absorption rate was measured by the reverberation chamber method, the results shown in FIG. 17 were obtained.
[0045]
(Example 12) The inorganic porous body was 200 mm (length) x 200 mm (width) x 25 mm (total thickness t), and the cross-sectional area of the upper side (200 mm) was the cross-sectional area of the lower side (190 mm) 1.11 times, the thickness t1 of the upper part (11 mm) is 0.78 times the thickness t2 of the lower part (14 mm) and the depth is 14 mm at the bottom, that is, 56% of the total thickness (25 mm). A plurality of sound absorbing parts are formed by forming a concave portion that occupies 42.8% of the total area of the bottom surface (5 grooves of 16 mm width). Body Formed. When these sound absorbers were arranged in the same manner as in Example 10 and the sound absorption rate was measured by the reverberation chamber method, the results shown in FIG. 18 were obtained.
[0046]
(Example 13) The inorganic porous body was 200 mm (length) x 200 mm (width) x 30 mm (total thickness t), and the cross-sectional area of the upper side (200 mm) was the cross-sectional area of the lower side (190 mm) 1.11 times, the thickness t1 of the upper part (10 mm) is 0.5 times the thickness t2 of the lower part (20 mm) and the depth is 19 mm at the bottom, that is, 63% of the total thickness (30 mm) A plurality of sound absorbing parts are formed by forming a concave portion that occupies 42.8% of the total area of the bottom surface (5 grooves of 16 mm width). Body Formed. These sound absorbers were arranged in the same manner as in Example 10, and the sound absorption rate was measured by the reverberation chamber method. The results shown in FIG. 19 were obtained.
[0047]
That is, A recess was provided at the bottom. Sound absorption made of inorganic porous material Body As is clear from the measurement results of Examples 8 to 13 that were used, a sound absorber made of an inorganic porous material and provided with a recess at the bottom was spaced between adjacent upper portions. It has been confirmed that the sound absorption characteristics are further improved by arranging them at a distance. Moreover, it has been found that the sound absorption characteristics can be further improved as the depth of the recess and the opening area are increased.
[0048]
In consideration of the effect of the above embodiment of the present invention, in the case where the concave portion is provided at the bottom of the sound absorber made of the inorganic porous material, the total thickness t is increased to, for example, more than 30 mm and practically used. The sound absorption characteristics are further improved by increasing the depth of the recess and the total opening area within the range that does not hinder the strength and handling of the product, and increasing the volume of the closed space comparable to the air layer as much as possible. You can get ugly to get. Therefore, the present invention can also be applied to a sound absorber made of an inorganic porous body having a total thickness t exceeding 30 mm.
[0049]
【The invention's effect】
As described above, according to the present invention, The sound absorber is Porous that can be easily obtained and manufactured as a normal ceramic product Material Give a specific shape do it Since it can be formed, it can be provided at low cost without causing technical difficulties.
[0050]
In addition, these sound absorbers are arranged at an appropriate interval between adjacent upper parts within a range of 0 to 10 mm, and are fixedly arranged on the attachment target member via the respective bottom surfaces, so that the space between each other is obtained. Excellent sound absorption characteristics can be obtained while securing the portion.
[0051]
In addition, the sound absorber can be directly fixed and attached to the side of the member to be attached without providing an air layer or using auxiliary materials, thus simplifying the construction and contributing to cost reduction. In addition, it can be constructed with a high degree of design freedom without being restricted by the location.
[0052]
Furthermore, when the sound absorber has a recessed portion made of a groove or the like on the bottom surface of the lower side portion, it is possible to ensure a closed space comparable to the air layer when fixed to the attachment target member, More preferable sound absorption characteristics can be exhibited.
[Brief description of the drawings]
FIG. 1 shows the present invention. Used Sound absorption body The top view about an example.
FIG. 2 is a longitudinal sectional view in the direction of arrows AA in FIG.
FIG. 3 is the sound absorption of FIG. body The longitudinal cross-sectional view which shows the modification about this corresponding to FIG.
FIG. 4 shows the present invention. Used Sound absorption body The top view about the other example.
FIG. 5 shows an example of a sound absorbing structure according to the present invention, in which (A) is a partial plan view of a portion where four sound absorbing bodies are combined, and (B) is B- in (A). A longitudinal sectional view in the direction of arrow B is shown respectively.
FIG. 6 is a graph showing sound absorption characteristics for a comparative example.
7 is a graph showing sound absorption characteristics for Example 1. FIG.
8 is a graph showing sound absorption characteristics for Example 2. FIG.
9 is a graph showing sound absorption characteristics for Example 3. FIG.
10 is a graph showing sound absorption characteristics for Example 4. FIG.
11 is a graph showing sound absorption characteristics for Example 5. FIG.
12 is a graph showing the sound absorption characteristics of Example 6. FIG.
13 is a graph showing sound absorption characteristics for Example 7. FIG.
14 is a graph showing sound absorption characteristics for Example 8. FIG.
15 is a graph showing the sound absorption characteristics of Example 9. FIG.
16 is a graph showing sound absorption characteristics for Example 10. FIG.
17 is a graph showing sound absorption characteristics for Example 11. FIG.
18 is a graph showing sound absorption characteristics for Example 12. FIG.
19 is a graph showing sound absorption characteristics for Example 13. FIG.
[Explanation of symbols]
12 Sound absorber
13 Upper part
14 Side edges
15 Lower side
16 Bottom
17 Recess

Claims

Ri each cross-sectional shape is Na vertical sectional shape at the site containing the lower side between the upper portion and the lower portion of similarity becomes polygon shapes approximately T-shape, the lower the cross-sectional area of the upper portion A sound absorber formed under a distribution ratio of 1.01 to 2.1 times the cross-sectional area of the side portion and 1.0 to 0.4 times the thickness of the upper side portion is used. The sound absorber is characterized in that a plurality of the sound absorbers are arranged at an appropriate interval so that adjacent upper parts come in contact with each other within a range of 0 to 10 mm, and are fixedly disposed on the attachment target member via respective bottom surfaces. Structure.

The sound absorbing structure according to claim 1, wherein the sound absorbing body is made of a porous material having a bulk specific gravity of 0.3 to 1.8.

Wherein the bottom surface of the lower portion of the sound absorber, a 8-70% of the depth with respect to the total thickness, and the distribution ratio of the total opening area to the total area of the bottom surface is 20-50% 請 Motomeko 1 or 2 the sound absorbing structure according recessed portion formed under the that provided.

The recessed portion is 1 or more grooves der Ru請 Motomeko 3 sound absorbing structure according arranged at appropriate intervals.

The sound absorbing body, to bulk specific gravity 請 Motomeko 2 no that are formed by ceramic fiber-based board is 0.3 to 1.1 4 Noise Re sound absorbing structure crab according.

The sound absorbing body has a bulk specific gravity of 4 to porosity 請 Motomeko 2 no that is formed by an inorganic porous body formed by sintering the inorganic particles so that 10% to 30% in 1.4 to 1.8 Izu Re sound absorbing structure crab according.