JP6883807B2 - Method for designing sound absorbing characteristics of flexible sound absorbing materials, sound absorbing bodies, acoustic diffusers, and sound processing bodies - Google Patents

Method for designing sound absorbing characteristics of flexible sound absorbing materials, sound absorbing bodies, acoustic diffusers, and sound processing bodies Download PDF

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JP6883807B2
JP6883807B2 JP2019042174A JP2019042174A JP6883807B2 JP 6883807 B2 JP6883807 B2 JP 6883807B2 JP 2019042174 A JP2019042174 A JP 2019042174A JP 2019042174 A JP2019042174 A JP 2019042174A JP 6883807 B2 JP6883807 B2 JP 6883807B2
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sound absorbing
absorbing material
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wood
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十太郎 泉田
十太郎 泉田
杉山 浩之
浩之 杉山
充宏 桂
充宏 桂
友昭 植村
友昭 植村
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けせんプレカット事業協同組合
新日本工業株式会社
株式会社鴻池組
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本発明は可撓性吸音材、吸音体、音響拡散体、および音処理体の吸音特性設計方法に係り、特に木材を利用した吸音材等に関する。 The present invention relates to a method for designing sound absorbing characteristics of a flexible sound absorbing material, a sound absorbing body, an acoustic diffuser, and a sound processing body, and particularly relates to a sound absorbing material using wood and the like.

平成22年に施行された「公共建築物等における木材の利用の促進に関する法律」により、公共建築物を中心に木質内装化が進められている。木材を利用する動きは活発であり、自治体の助成を得て保育園の音響改修を行った事例もみられる(後記非特許文献1)。公共施設では、用途に応じた音響性能が要求されることもあり、これまでにも木材を利用した吸音材料の開発例(後記非特許文献2)がみられる。 According to the "Act on Promotion of the Use of Wood in Public Buildings, etc." that came into effect in 2010, wood interiors are being promoted mainly in public buildings. The movement to use wood is active, and there are cases where the acoustic repair of the nursery school was carried out with the support of the local government (Non-Patent Document 1 below). In public facilities, acoustic performance may be required according to the application, and examples of development of sound absorbing materials using wood (Non-Patent Document 2 described later) have been seen so far.

また、木材を用いた吸音材については特許出願等による技術的提案もなされている。たとえば後記特許文献1には共鳴を利用した簡易な構造の吸音パネルとして、平板と波板を重ね合わせた吸音パネルとし、これにより形成される管共鳴を生じる複数の空洞には、平板側から開口部を設ける構成が開示されている。そして、波板側を天井や壁といった固定対象に固定して用いることで、簡素化した構成の吸音パネルを提供可能であるとしている。 In addition, technical proposals such as patent applications have been made for sound absorbing materials using wood. For example, in Patent Document 1 described later, as a sound absorbing panel having a simple structure using resonance, a sound absorbing panel in which a flat plate and a corrugated plate are superposed is provided, and a plurality of cavities formed by this that generate tube resonance are opened from the flat plate side. The configuration in which the part is provided is disclosed. Then, by fixing the corrugated sheet side to a fixed object such as a ceiling or a wall, it is possible to provide a sound absorbing panel having a simplified configuration.

特開2009−30431号公報「吸音パネルおよび音響室並びに室内音響特性調整方法」Japanese Unexamined Patent Publication No. 2009-30431 "Sound Absorption Panel, Acoustic Room, and Room Acoustic Characteristic Adjustment Method"

川井ら,“保育室内の吸音による喧噪感の緩和−地元産木材を利用した吸音材による音響改修事例−”,日本建築学会大会学術講演梗概集pp.117−118(2012.9)Kawai et al., "Relieving the noisy feeling due to sound absorption in the nursery room-A case of acoustic repair using sound absorbing material using locally produced wood-", Architectural Institute of Japan Conference Academic Lecture Abstracts pp. 117-118 (2012.9) 末吉ら,“木質スリットパネルの吸音特性”,木材学会誌59,(2013)Sueyoshi et al., "Sound Absorption Characteristics of Wood Slit Panel", Journal of the Wood Society 59, (2013)

このように従来、木材を利用した吸音材料の開発例は複数認められる。しかし、それらはいずれも変形させることのできない固定した形状のものであり、たとえば湾曲した壁面に対応して設置可能なように、変形して曲面を形成できる程度の可撓性を有する吸音材は、従来存在しない。 As described above, there have been a plurality of examples of development of sound absorbing materials using wood. However, all of them have a fixed shape that cannot be deformed. For example, a sound absorbing material that is flexible enough to be deformed to form a curved surface so that it can be installed corresponding to a curved wall surface. , Conventionally does not exist.

そこで本発明が解決しようとする課題は、かかる従来技術の状況を踏まえ、変形により曲面を形成できる程度の可撓性を有する吸音材を提供することである。また、特に、かかる吸音材として、木製の吸音材を提供することである。 Therefore, an object to be solved by the present invention is to provide a sound absorbing material having flexibility enough to form a curved surface by deformation, based on the situation of the prior art. Further, in particular, a wooden sound absorbing material is provided as such a sound absorbing material.

本願発明者は上記課題について検討した結果、板材の両面に溝を交互に設けることで可撓性をもたせた化粧材を用いることを、まず想到した。しかし、この種の板材は板振動型の吸音特性を有するが、中高音域における吸音効果はさほど期待できない。そこで、この板材の一方面に、溝と直交する第二の溝(切り込み)を等間隔で設けることにより、ヘルムホルツ共鳴器型の吸音特性をもつ木質系吸音材を試作した。その結果、かかる構成によって課題を解決できることを見出し、これに基づいて本発明を完成するに至った。すなわち、上記課題を解決するための手段として本願で特許請求される発明、もしくは少なくとも開示される発明は、以下の通りである。 As a result of examining the above problems, the inventor of the present application first came up with the idea of using a decorative material having flexibility by alternately providing grooves on both sides of the plate material. However, although this type of plate material has a plate vibration type sound absorption characteristic, the sound absorption effect in the mid-high range cannot be expected so much. Therefore, a wood-based sound absorbing material having Helmholtz resonator-type sound absorbing characteristics was prototyped by providing second grooves (cuts) orthogonal to the grooves on one surface of this plate material at equal intervals. As a result, it has been found that the problem can be solved by such a configuration, and the present invention has been completed based on this. That is, the inventions claimed in the present application as means for solving the above problems, or at least the inventions disclosed, are as follows.

〔1〕 板材の表裏面に表裏交互にかつ平行に溝が複数設けられており、表裏面の少なくとも一方に共鳴型の吸音特性を有する共鳴型吸音構造が設けられており、該共鳴型吸音構造が、一方面側において該溝と交差する方向に設けられた複数の切り込み部であることを特徴とする、可撓性吸音材。
〕 前記切り込み部の深さ寸法が、下記<A>に示す板底厚さ寸法よりも大きく、それにより該切り込み部の箇所には表裏面を連通する開口部が形成されていることを特徴とする、〔〕に記載の可撓性吸音材。
<A> 板底厚さ = 板の厚さ ― 切り込み部と反対面の溝の深さ
〕 前記切り込み部が前記溝に直交して設けられていることを特徴とする、〔〕、〔〕のいずれかに記載の可撓性吸音材。
〕 前記板材が木質系であることを特徴とする、〔1〕、〔2〕、〔3〕のいずれかに記載の可撓性吸音材。
[1] plate has sides alternately and parallel grooves provided in plural on the front and back surfaces of, and resonance type sound absorbing structure having a resonance type sound absorbing properties to at least one of the front and back surfaces are provided, the resonance type sound absorbing structure However, the flexible sound absorbing material is characterized by having a plurality of cut portions provided in a direction intersecting the groove on one surface side.
[ 2 ] The depth dimension of the cut portion is larger than the plate bottom thickness dimension shown in <A> below, whereby an opening communicating with the front and back surfaces is formed at the cut portion. The flexible sound absorbing material according to [1 ], which is characterized.
<A> Plate bottom thickness = Plate thickness-Depth of the groove on the opposite surface to the notch [3 ] The notch is provided orthogonal to the groove, [ 1 ], The flexible sound absorbing material according to any one of [ 2].
[ 4 ] The flexible sound absorbing material according to any one of [1], [2], and [3] , wherein the plate material is made of wood.

〕 前記溝の構造および共鳴型吸音構造により、木の備える調湿作用および香り発散作用が高められていることを特徴とする、〔〕に記載の可撓性吸音材。
〕 前記板材の材料が下記<C>のいずれかであることを特徴とする、〔〕または〔〕に記載の可撓性吸音材。
<C> スギ、アオモリヒバ、ヒノキ、カラマツ、アカマツ、針葉樹(スギ、アオモリヒバ、ヒノキ、カラマツまたはアカマツを除く。)
〔1〕、〔2〕、〔3〕、〔4〕、〔5〕、〔6〕のいずれかに記載の可撓性吸音材を用いて形成されていることを特徴とする、吸音体。
〕 曲面をもって形成されていることを特徴とする、〔〕に記載の吸音体。
〕 前記可撓性吸音材の共鳴型吸音構造が設けられた面側に多孔質吸音材が設けられていることを特徴とする、〔〕または〔〕に記載の吸音体。
[ 5 ] The flexible sound absorbing material according to [4 ], wherein the groove structure and the resonance type sound absorbing structure enhance the humidity control action and the scent diverging action of wood.
[ 6 ] The flexible sound absorbing material according to [4 ] or [ 5 ], wherein the material of the plate material is any of the following <C>.
<C> Sugi, Aomori Hiba, Hinoki, Larch, Japanese red pine, Conifer (excluding Sugi, Aomori Hiba, Japanese cypress, Japanese larch or Japanese red pine)
[ 7 ] It is characterized in that it is formed by using the flexible sound absorbing material according to any one of [1], [2], [3], [4], [5], and [6]. Sound absorber.
[ 8 ] The sound absorbing body according to [7 ], which is formed with a curved surface.
[ 9 ] The sound absorbing body according to [7 ] or [ 8 ], wherein the porous sound absorbing material is provided on the surface side of the flexible sound absorbing material provided with the resonance type sound absorbing structure.

10〔1〕、〔2〕、〔3〕、〔4〕、〔5〕、〔6〕のいずれかに記載の可撓性吸音材を用いて形成されていることを特徴とする、音響拡散体。
11〕 前記可撓性吸音材の共鳴型吸音構造が設けられた面側に多孔質吸音材が設けられていることを特徴とする、〔10〕に記載の音響拡散体。
12〔7〕、〔8〕、〔9〕のいずれかに記載の吸音体、または〔10〕、〔11〕のいずれかに記載の音響拡散体(以下、合わせて「音処理体」ともいう)における吸音特性を設計する方法であって、下記<P>記載の少なくともいずれかを変化させることを特徴とする、音処理体の吸音特性設計方法。
<P> 前記可撓性吸音材の板厚、開口率(前記開口部が該可撓性吸音材の表面面積に占める割合)、空気層厚さ(前記多孔質吸音材の厚さを含む)
[ 10 ] It is characterized in that it is formed by using the flexible sound absorbing material according to any one of [1], [2], [3], [4], [5], and [6]. Acoustic diffuser.
[ 11 ] The acoustic diffuser according to [10 ], wherein the porous sound absorbing material is provided on the surface side of the flexible sound absorbing material provided with the resonance type sound absorbing structure.
[ 12 ] The sound absorber according to any one of [7], [8], and [9] , or the acoustic diffuser according to any one of [10] and [11] (hereinafter collectively referred to as "sound processor"). A method for designing sound absorption characteristics in (also referred to as), wherein at least one of the following <P> is changed.
<P> Plate thickness of the flexible sound absorbing material, aperture ratio (ratio of the opening to the surface area of the flexible sound absorbing material), air layer thickness (including the thickness of the porous sound absorbing material).

本発明の可撓性吸音材、吸音体、音響拡散体、および音処理体の吸音特性設計方法は上述のように構成されるため、これらによれば、変形により曲面を形成できる程度の可撓性を有する吸音材を提供することができる。特に、かかる吸音材として木製の吸音材を提供することができる。本発明の可撓性吸音材は、曲面状態では250Hzから1000Hzの幅広い帯域で吸音性を有し、人の話し声の周波数を効率的に吸音することができる。 Since the method for designing the sound absorbing characteristics of the flexible sound absorbing material, the sound absorbing body, the acoustic diffuser, and the sound processing body of the present invention is configured as described above, according to these, the flexibility is such that a curved surface can be formed by deformation. A sound absorbing material having a property can be provided. In particular, a wooden sound absorbing material can be provided as such a sound absorbing material. The flexible sound absorbing material of the present invention has sound absorbing properties in a wide band of 250 Hz to 1000 Hz in a curved surface state, and can efficiently absorb the frequency of a human speaking voice.

また、本発明の可撓性吸音材は、その可撓性によって曲面を任意の曲率で作ることができるため、吸音体のみならず音響拡散体としても利用でき、拡散と吸音の両方の効果を得られる。さらに、本発明の音処理体の吸音特性設計方法によれば、板材の断面条件等を調節することによって様々な吸音特性の音処理体(吸音体や音響拡散体)を設計することができ、用途・環境などにより良く対応した音処理体を提供することも可能である。 Further, since the flexible sound absorbing material of the present invention can form a curved surface with an arbitrary curvature due to its flexibility, it can be used not only as a sound absorbing body but also as an acoustic diffuser, and has both diffusion and sound absorbing effects. can get. Further, according to the sound absorbing characteristic design method of the sound processing body of the present invention, it is possible to design a sound processing body (sound absorbing body or acoustic diffuser) having various sound absorbing characteristics by adjusting the cross-sectional conditions of the plate material. It is also possible to provide a sound processor that is better suited to the application and environment.

本発明可撓性吸音材の基本材の構成例を示す説明図である。It is explanatory drawing which shows the structural example of the basic material of the flexible sound absorbing material of this invention. 図1−1に示す構成例の写真図である。It is a photograph figure of the configuration example shown in FIG. 1-1. 本発明可撓性吸音材の構成例の要部斜視図である。It is a main part perspective view of the structural example of the flexible sound absorbing material of this invention. 本発明可撓性吸音材の構成例の斜視写真図である。It is a perspective photograph figure of the structural example of the flexible sound absorbing material of this invention. 本発明可撓性吸音材の構成例の正面視写真図である。(以下は、実施例に係る図面である。なお実施例においては、「可撓性吸音材」を「木質系吸音材」としている。)It is a front view photograph of the structural example of the flexible sound absorbing material of this invention. (The following is a drawing according to an embodiment. In the embodiment, the "flexible sound absorbing material" is referred to as a "wooden sound absorbing material".) 本発明木質系吸音材の試験体(平面状態)の試験条件を示す説明図である。It is explanatory drawing which shows the test condition of the test body (planar state) of the wood-based sound absorbing material of this invention. 図2−1に係る吸音率測定試験に用いた試験体の構成を示す断面図である。It is sectional drawing which shows the structure of the test body used for the sound absorption coefficient measurement test which concerns on FIG. 2-1. 図2−2に示す試験体の吸音率測定結果を示すグラフである。It is a graph which shows the sound absorption coefficient measurement result of the test body shown in FIG. 2-2. 本発明木質系吸音材の試験体(曲面状態)の試験条件を示す説明図である。It is explanatory drawing which shows the test condition of the test body (curved surface state) of the wood-based sound absorbing material of this invention. 図3−1に係る吸音率測定試験に用いた試験体の構成を示す断面図である。It is sectional drawing which shows the structure of the test body used for the sound absorption coefficient measurement test which concerns on FIG. 3-1. 図3−2に示す試験体の吸音率測定結果を示すグラフである。It is a graph which shows the sound absorption coefficient measurement result of the test body shown in FIG. 3-2. 本発明木質系吸音材の試験体(断面条件検討全般)の試験条件を示す説明図である。It is explanatory drawing which shows the test condition of the test body (general examination of a cross-sectional condition) of the wood-based sound absorbing material of this invention. 吸音率測定試験(空気層条件)に用いた試験体の構成を示す断面図である。It is sectional drawing which shows the structure of the test body used for the sound absorption coefficient measurement test (air layer condition). 図5−1に示す試験体の吸音率測定結果を示すグラフである。It is a graph which shows the sound absorption coefficient measurement result of the test body shown in FIG. 5-1. 吸音率測定試験(開口率条件)に用いた試験体の構成を示す断面図である。It is sectional drawing which shows the structure of the test body used for the sound absorption coefficient measurement test (aperture ratio condition). 図6−1に示す試験体の吸音率測定結果を示すグラフである。It is a graph which shows the sound absorption coefficient measurement result of the test body shown in FIG. 6-1. 吸音率測定試験(板厚条件)に用いた試験体の構成を示す断面図である。It is sectional drawing which shows the structure of the test body used for the sound absorption coefficient measurement test (plate thickness condition). 図7−1に示す試験体の吸音率測定結果を示すグラフである。It is a graph which shows the sound absorption coefficient measurement result of the test body shown in FIG. 7-1.

以下、図面により本発明を詳細に説明する。
図1−1は本発明可撓性吸音材の基本材の構成例を示す説明図、図1−2は図1−1に示す構成例の写真図である。また、
図1−3は本発明可撓性吸音材の構成例の要部斜視図、図1−4は同じく斜視写真図、図1−5は正面視写真図である。なお図1−1は、基本材の平面図(a)、側面図(b)、正面図(c)により構成されている。また図1−2は斜視写真(a)、可撓性示す写真(b)から構成されている。これらに示すように本可撓性吸音材5は、板材1の表裏面に、表裏交互に、かつ平行に溝2が複数設けられており、表裏面の少なくとも一方に共鳴型の吸音特性を有する共鳴型吸音構造3が設けられていることを、主たる構成とする。
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1-1 is an explanatory view showing a configuration example of the basic material of the flexible sound absorbing material of the present invention, and FIG. 1-2 is a photographic view of the configuration example shown in FIG. 1-1. Also,
FIG. 1-3 is a perspective view of a main part of a configuration example of the flexible sound absorbing material of the present invention, FIG. 1-4 is a perspective photograph, and FIG. 1-5 is a front view photograph. Note that FIG. 1-1 is composed of a plan view (a), a side view (b), and a front view (c) of the basic material. Further, FIG. 1-2 is composed of a perspective photograph (a) and a photograph (b) showing flexibility. As shown in these, the flexible sound absorbing material 5 is provided with a plurality of grooves 2 alternately and in parallel on the front and back surfaces of the plate material 1, and has resonance type sound absorbing characteristics on at least one of the front and back surfaces. The main configuration is that the resonance type sound absorbing structure 3 is provided.

すなわち本発明可撓性吸音材5は、板材1の表裏面に所定の形態による複数の溝2が設けられてなる基本材0(図1−1等)の一方面に、共鳴型吸音構造3が設けられて構成されている。基本材0は、図1−2に示すように手で簡単に、かつ任意の曲率で撓ませることができる(図1−2中、(b))。基本材0のままでは中高音域における高い吸音効果が期待できないが、本発明可撓性吸音材5の構成では共鳴型吸音構造3を備えるために、ヘルムホルツ共鳴器型の吸音特性が得られる。 That is, the flexible sound absorbing material 5 of the present invention has a resonance type sound absorbing structure 3 on one surface of a basic material 0 (FIG. 1-1, etc.) in which a plurality of grooves 2 in a predetermined form are provided on the front and back surfaces of the plate material 1. Is provided and configured. As shown in FIG. 1-2, the basic material 0 can be easily bent by hand with an arbitrary curvature (in FIG. 1-2, (b)). Although a high sound absorbing effect in the mid-high range cannot be expected with the basic material 0 as it is, the Helmholtz resonator type sound absorbing characteristic can be obtained in the configuration of the flexible sound absorbing material 5 of the present invention because the resonance type sound absorbing structure 3 is provided.

空洞に孔が開いた形態であるヘルムホルツ共鳴器型では、共鳴型吸音構造に音が当たることによって共鳴周波数の近くで孔の部分の空気が激しく振動し、音は周辺との摩擦熱として消費される。そのため、その共鳴周波数において非常に大きな吸音率になるという吸音特性を有する。本可撓性吸音材5では、中高音域における高い吸音効果を得ることができる。特に曲面状態では、250Hzから1000Hzの幅広い帯域で吸音性を有するため、人の話し声の周波数を効率的に吸音することができる。 In the Helmholtz resonator type, which has a hole in the cavity, the sound hits the resonance type sound absorbing structure, causing the air in the hole to vibrate violently near the resonance frequency, and the sound is consumed as frictional heat with the surroundings. To. Therefore, it has a sound absorption characteristic that the sound absorption coefficient becomes very large at the resonance frequency. With this flexible sound absorbing material 5, a high sound absorbing effect in the mid-high range can be obtained. In particular, in the curved surface state, since it has sound absorption in a wide band from 250 Hz to 1000 Hz, it is possible to efficiently absorb the frequency of the human speaking voice.

図1−2等に示す通り本可撓性吸音材5の基本材0は、表裏面に設けられた複数の溝3による矩形波的な形態により、可撓性を備える。しかも、曲面を任意の曲率で形成できるため、吸音体としても音響拡散体としても利用できる。さらに本可撓性吸音材5は、曲面にて形成される壁面等にも自在に適用することができるため、良好な吸音特性を有する吸音材の適用範囲・対象を広げることができる。 As shown in FIG. 1-2 and the like, the basic material 0 of the flexible sound absorbing material 5 has flexibility due to a rectangular wave shape formed by a plurality of grooves 3 provided on the front and back surfaces. Moreover, since the curved surface can be formed with an arbitrary curvature, it can be used as both a sound absorber and an acoustic diffuser. Further, since the flexible sound absorbing material 5 can be freely applied to a wall surface or the like formed by a curved surface, the applicable range and target of the sound absorbing material having good sound absorbing characteristics can be expanded.

なお、溝2の形態は図示するように、その断面(側面)が一定形状かつ一定サイズの長方形であるようにすることが望ましい。同一形態の溝が表裏面F、Rそれぞれに平行して、かつ互い違いに設けられる構成とすることにより、人の手で容易にかつ任意の曲率で折り曲げて曲面化可能な可撓性を備えることができる。 As shown in the figure, it is desirable that the groove 2 has a rectangular cross section (side surface) having a constant shape and a constant size. By making the grooves of the same shape parallel to and alternately provided on the front and back surfaces F and R, the flexibility is provided so that the grooves can be easily bent by a human hand at an arbitrary curvature to form a curved surface. Can be done.

基本材0を示す図1−2等、可撓性吸音材5を示す図1−4の通り、板材1としては木質系の材料、殊に木材を好適に用いることができる。これについてはさらに後述する。なお、木材以外の木質系材料としてはたとえば、木粉の成型材等を挙げることができる。 As shown in FIG. 1-2 showing the basic material 0 and FIG. 1-4 showing the flexible sound absorbing material 5, a wood-based material, particularly wood, can be preferably used as the plate material 1. This will be described later. Examples of wood-based materials other than wood include wood powder molding materials and the like.

本可撓性吸音材5の共鳴型吸音構造3は具体的には、一方面側において溝2と交差する方向に設けられた複数の切り込み部3にて形成することができる。この切り込み部3は、溝2に対して直交して設けるものとすることができる。切り込み部3の形状は、図1−4に示すように断面が任意の矩形の溝状とすることができる。本発明がそれに限定されるものではないが、かかる形状により十分な作用効果を得られる上、製造も容易であるため、好適である。なお、共鳴型吸音構造を構成するための孔の機能を、切り込み部3が奏する。 Specifically, the resonance type sound absorbing structure 3 of the flexible sound absorbing material 5 can be formed by a plurality of cut portions 3 provided in a direction intersecting the groove 2 on one surface side. The cut portion 3 may be provided orthogonal to the groove 2. The shape of the cut portion 3 can be a groove shape having an arbitrary rectangular cross section as shown in FIGS. 1-4. Although the present invention is not limited thereto, it is suitable because such a shape can obtain a sufficient effect and effect and is easy to manufacture. The notch portion 3 plays the function of a hole for forming a resonance type sound absorbing structure.

切り込み部3の深さ寸法は、下記<A>に示す板底厚さ寸法よりも大きくし、 <A> 板底厚さ = 板の厚さ ― 切り込み部3と反対面の溝2の深さ
それにより本可撓性吸音材5は、図1−5に示すように、切り込み部3の箇所に表裏面を連通する開口部4が形成された構成とすることができる。かかる構成によって、ヘルムホルツ共鳴器型の吸音特性をより十全に得ることができる。
The depth dimension of the notch 3 is larger than the plate bottom thickness dimension shown in <A> below, and <A> plate bottom thickness = plate thickness-the depth of the groove 2 on the opposite surface to the notch 3. As a result, as shown in FIG. 1-5, the flexible sound absorbing material 5 can be configured such that an opening 4 communicating with the front and back surfaces is formed at the notch portion 3. With such a configuration, the sound absorption characteristics of the Helmholtz resonator type can be obtained more fully.

本可撓性吸音材5は木質製とすることができるのは上述の通りだが、溝2の有するジグザグ形態、および共鳴型吸音構造(切り込み部)3の有する凹状形態やそれによる開口部4の開口形態は、表面積を増大させる形態でもある。これによって、木質系材料の備える調湿作用や香り発散作用を高めることができる。調質作用や香り発散作用は、建物の内装材として有利な特質であり、望ましい。かかる効果は、板材1として木材を用いることによって、より良好に得ることができる。 As described above, the flexible sound absorbing material 5 can be made of wood, but the zigzag shape of the groove 2, the concave shape of the resonance type sound absorbing structure (cut portion) 3, and the opening 4 thereof. The opening form is also a form that increases the surface area. This makes it possible to enhance the humidity control action and the scent divergence action of the wood-based material. The tempering action and the scent diverging action are advantageous characteristics as a building interior material and are desirable. Such an effect can be better obtained by using wood as the plate material 1.

板材1の材料としては木材が好適であり、樹種としては広葉樹も用いることができるが、下記<C>に挙げた針葉樹種は特に好適に用いることができる。
<C> スギ、アオモリヒバ、ヒノキ、カラマツ、アカマツ、その他の針葉樹
このうちスギには、下記の特長がある。
1)素材が非常に柔らかい。
2)他樹種よりも調湿効果に優れる。
3)空気浄化作用に優れる。
4)断熱効果に優れる。
5)素材の柔らかさによる優美さがあり、また、目にも優しい。
Wood is preferable as the material of the plate material 1, and hardwood can be used as the tree species, but the coniferous tree species listed in <C> below can be particularly preferably used.
<C> Sugi, Aomori Hiba, Hinoki, Larch, Japanese red pine, and other conifers Of these, Sugi has the following features.
1) The material is very soft.
2) Excellent humidity control effect compared to other tree species.
3) Excellent air purification effect.
4) Excellent heat insulation effect.
5) There is grace due to the softness of the material, and it is also gentle on the eyes.

また、アオモリヒバには下記の特長がある。
1)表面積が大きいため、発散される香りが多く、精神安定作用が大きい。
2)抗菌作用がある(菌を寄せ付けない)。
3)防虫作用があり、シロアリ、ダニ、ノミ、ゴキブリ、蚊等に対する忌避(除虫)効果がある。
4)消臭作用があり、環境中の嫌なにおいを消す。
In addition, Aomori Hiba has the following features.
1) Due to its large surface area, it emits a large amount of scent and has a large tranquilizing effect.
2) Has antibacterial action (repels bacteria).
3) It has an insect repellent effect and has a repellent (insect repellent) effect against termites, mites, fleas, cockroaches, mosquitoes, etc.
4) It has a deodorant effect and eliminates unpleasant odors in the environment.

なお、スギ、アオモリヒバの特長として挙げた点は、これらを含む針葉樹全般においてもある程度は該当するが、スギ、アオモリヒバにおける特に優れた効果を挙げたものである。 The points mentioned as the features of Sugi and Aomori Hiba are applicable to some conifers including these, but they are particularly excellent in Sugi and Aomori Hiba.

以上説明したいずれかの本発明可撓性吸音材5を用いて形成される吸音体や音響拡散体もまた本発明の範囲内であり、いずれも曲面をもって形成されているものとすることができる。また、吸音体、音響拡散体のいずれにおいても、その共鳴型吸音構造(切り込み部)が設けられた面側に、多孔質吸音材が設けられている構成とすることができる。多孔質吸音材としては、たとえばグラスウール等の従来公知のものを適宜用いることができる。 The sound absorbing body and the acoustic diffuser formed by using any of the flexible sound absorbing materials 5 of the present invention described above are also within the scope of the present invention, and both can be formed with a curved surface. .. Further, in both the sound absorbing body and the acoustic diffuser, the porous sound absorbing material can be provided on the surface side where the resonance type sound absorbing structure (cut portion) is provided. As the porous sound absorbing material, a conventionally known material such as glass wool can be appropriately used.

なお、以上説明したいずれかの吸音体、または音響拡散体(合わせて「音処理体」)における吸音特性を設計する方法であって、
<P> 前記可撓性吸音材の板厚、開口率(前記開口部が該可撓性吸音材の表面面積に占める割合)、空気層厚さ(前記多孔質吸音材の厚さを含む)
の少なくともいずれかを変化させることによって音処理体の吸音特性を設計する方法もまた、本発明の範囲内である。これによれば、板材の断面条件等を適宜に調節することによって、様々な吸音特性の音処理体を設計することができる。すなわち、用途・環境などにより良く対応した音処理体を提供することができる。
It should be noted that this is a method of designing the sound absorbing characteristics of any of the sound absorbing bodies or acoustic diffusers (collectively, "sound processing bodies") described above.
<P> Plate thickness of the flexible sound absorbing material, aperture ratio (ratio of the opening to the surface area of the flexible sound absorbing material), air layer thickness (including the thickness of the porous sound absorbing material).
A method of designing the sound absorption characteristics of a sound processor by changing at least one of the above is also within the scope of the present invention. According to this, it is possible to design a sound processing body having various sound absorbing characteristics by appropriately adjusting the cross-sectional conditions of the plate material and the like. That is, it is possible to provide a sound processing body that is better suited to the application, environment, and the like.

以下、本発明の実施例を説明するが、本発明が、数値や仕様を初めとする実施例に限定されるものではない。なお、本発明完成に至る実験経過の概要をもって実施例とする。
<実施例1 可撓性木質系吸音材の吸音特性に関する実験>
1.−1 目的
可撓性を有する化粧材に通気性をもたせた木質系吸音材を試作し、多孔質吸音材との組み合わせ、空気層厚さ、および断面形状(平面か曲面か)による吸音特性の違いを解明することを目的として、実験を行った。
Hereinafter, examples of the present invention will be described, but the present invention is not limited to the examples including numerical values and specifications. An outline of the experimental process leading to the completion of the present invention will be used as an example.
<Example 1 Experiment on sound absorption characteristics of flexible wood-based sound absorbing material>
1. 1. -1 Purpose We made a prototype of a wood-based sound absorbing material that has breathability in a flexible decorative material, and combined it with a porous sound absorbing material, the thickness of the air layer, and the sound absorbing characteristics depending on the cross-sectional shape (flat or curved). Experiments were conducted with the aim of clarifying the differences.

1.−2 試験体の概要
前掲図1−1、1−2に示した基本材を用いた。これは木質板材料に加工を施したものであり、具体的には、幅3mmの溝を板材の表裏面交互に設けることで可撓性を持たせた化粧材である。この種の板材は板振動型の吸音特性のため、中高音域における高い吸音効果は期待できない。そこで、前掲図1−3に示すように、溝の直交方向に幅20mm、高さ5mmの切込みを、40mm 間隔で入れることにより、ヘルムホルツ共鳴器型の吸音特性をもつ試験体(以下「木質系吸音材」とする)を製作した。
1. 1. -2 Outline of test specimen The basic materials shown in Figures 1-1 and 1-2 above were used. This is a wood board material processed, and specifically, it is a decorative material in which grooves having a width of 3 mm are provided alternately on the front and back surfaces of the board to give flexibility. Since this type of plate material has a plate vibration type sound absorption characteristic, a high sound absorption effect in the mid-high range cannot be expected. Therefore, as shown in Fig. 1-3 above, by making notches with a width of 20 mm and a height of 5 mm in the orthogonal direction of the groove at intervals of 40 mm, a test body having Helmholtz resonator type sound absorption characteristics (hereinafter referred to as "wooden system"). "Sound absorbing material") was manufactured.

スリットの場合におけるヘルムホルツ共鳴器の共鳴周波数は、空気層が波長λに比して小さい場合、L<λ/16 を仮定し、下記式(1)のように表される。ただし、cは空気中の音速、tはネック長、Lは背後空気層の厚さ、Pは開口率である。また、開口端補正値δはスリット幅bとの間で、δ=Kb の関係にあり、Kは下記式(2)のように与えられる。aはスリットの高さである。 The resonance frequency of the Helmholtz resonator in the case of a slit is expressed by the following equation (1) assuming L <λ / 16 when the air layer is smaller than the wavelength λ. However, c is the speed of sound in the air, t is the neck length, L is the thickness of the back air layer, and P is the aperture ratio. Further, the end correction value δ has a relationship of δ = Kb with the slit width b, and K is given by the following equation (2). a is the height of the slit.

Figure 0006883807
Figure 0006883807

Figure 0006883807
Figure 0006883807

1.−3 木質系吸音材の吸音特性
1.−3−(1) 測定方法
吸音率は、残響室(室容積100m、室表面積133m)において、残響室法吸音率測定方法により求めた。また、試料面積は5.28m(2m×2.64m)とした。
1. 1. -3 Sound absorption characteristics of wood-based sound absorbing material 1. -3- (1) Measurement method The sound absorption coefficient was determined by the reverberation room method sound absorption coefficient measurement method in the reverberation room (room volume 100 m 3 , room surface area 133 m 2 ). The sample area was 5.28 m 2 (2 m × 2.64 m).

1.−3−(2) 平面状態での測定結果
木質系吸音材の基本的な吸音特性を把握するため、まず、平面状態での切込みの有無、および空気層厚さによる吸音特性を比較検討した。
図2−1は、本発明木質系吸音材の試験体(平面状態)の試験条件を示す説明図であり、試験体の断面条件をまとめた表と切り込み部の断面図とからなる。また、図2−2は、吸音率測定試験に用いた各試験体(No.1〜4)の構成を示す断面図である。これらに示すように本試験では、切り込み部の有無、空気層の厚さ(木質系吸音材から設置面までの距離(25mm、50mm)、および空気層における多孔質吸音材(グラスウール)の有無の各条件より、No.1〜4の計4点につき試験した。なお、用いたグラスウールの質量は24kg/mである。
1. 1. -3- (2) Measurement results in a flat state In order to understand the basic sound absorption characteristics of a wood-based sound absorbing material, first, the presence or absence of a notch in a flat state and the sound absorption characteristics depending on the thickness of the air layer were compared and examined.
FIG. 2-1 is an explanatory view showing the test conditions of the test body (planar state) of the wood-based sound absorbing material of the present invention, and includes a table summarizing the cross-sectional conditions of the test body and a cross-sectional view of the cut portion. Further, FIG. 2-2 is a cross-sectional view showing the configuration of each test body (No. 1 to 4) used in the sound absorption coefficient measurement test. As shown in these, in this test, the presence or absence of a notch, the thickness of the air layer (distance from the wood-based sound absorbing material to the installation surface (25 mm, 50 mm), and the presence or absence of the porous sound absorbing material (glass wool) in the air layer). From each condition, a total of 4 points of Nos. 1 to 4 were tested. The mass of the glass wool used was 24 kg / m 3 .

図2−3は、各試験体(平面状態)の吸音率測定結果を示すグラフである。図中に示したfは、前掲式(1)において、開口率P=12.5%、ネック長t=20mmの場合の共鳴周波数計算値である(以下の各図でも同様)。図示するように、背後空気層(背後吸音層)としてグラスウール(GW)を挿入し、その厚さを50mmとした試験体No.4の測定結果は、400Hzに吸音率のピークが現れた。また、GW厚を25mmとした試験体No.3では、800Hzにピークがみられた。一方、背後空気層にGWを設けなかった試験体No.1、2の吸音率は低く、0.5以下であった。 FIG. 2-3 is a graph showing the sound absorption coefficient measurement results of each test piece (planar state). F 0 shown in the figure is a resonance frequency calculated value when the aperture ratio P = 12.5% and the neck length t = 20 mm in the above-mentioned formula (1) (the same applies to each of the following figures). As shown in the figure, the test piece No. in which glass wool (GW) was inserted as the back air layer (back sound absorbing layer) and the thickness was 50 mm. As for the measurement result of No. 4, the peak of the sound absorption coefficient appeared at 400 Hz. In addition, the test piece No. with a GW thickness of 25 mm. At 3, a peak was observed at 800 Hz. On the other hand, the test piece No. in which the GW was not provided in the back air layer. The sound absorption coefficient of 1 and 2 was low, 0.5 or less.

吸音率は、0.5以上であれば吸音材としての利用価値があるとされている。図示するように、GWを挿入した2つの木質系吸音材(試験体No.3、4)は吸音率0.5以上の周波数帯域がある。したがってこれらについては吸音材たる条件を満たしており、吸音材としての利用が可能と考えられた。なお、これら本発明木質系吸音材を用いたNo.3、4の吸音率が、低中音域におけるGW単独使用の場合の吸音率を上回っていることは確認済みである。なお、切り込み部無しの試験体No.1では250Hzに吸音のピークが見られるが、これは、板振動型の吸音特性が現れたものと考えられる。 If the sound absorption coefficient is 0.5 or more, it is said to be useful as a sound absorbing material. As shown in the figure, the two wood-based sound absorbing materials (test bodies No. 3 and 4) into which the GW is inserted have a frequency band having a sound absorbing coefficient of 0.5 or more. Therefore, these satisfy the conditions of being a sound absorbing material, and it is considered that they can be used as a sound absorbing material. In addition, No. 1 using these wood-based sound absorbing materials of the present invention. It has been confirmed that the sound absorption coefficient of 3 and 4 exceeds the sound absorption coefficient when GW is used alone in the low and middle range. In addition, the test piece No. without a notch. In No. 1, a peak of sound absorption is seen at 250 Hz, which is considered to be due to the appearance of the plate vibration type sound absorption characteristic.

1.−3−(3) 曲面状態での測定結果
平面状態での試験結果を踏まえ、次に、木質系吸音材と多孔質吸音材(GW)とを組み合わせた試験体により、曲面状態での吸音特性の測定を行った。
図3−1は、本発明木質系吸音材の試験体(曲面状態)の試験条件を示す説明図であり、試験体の曲率・断面条件をまとめた表と吸音材設置状況を示す斜視図とからなる。また、図3−2は、吸音率測定試験に用いた各試験体(No.5〜10)の構成を示す断面図である。これらに示すように本試験では、曲面の曲率の大きさ(大・中・小の3段階)、および背後吸音層として設けるGWの厚さ(25mm、50mm)の各条件より、No.5〜10の計6点につき試験した。また、GWは木質系吸音材の背後に接した状態に設けた。試料面積は、平面状態での試験と同様の5.28mとした。なお、試験体の両側面は塞いだ状態とした。
1. 1. -3- (3) Measurement results in a curved surface state Based on the test results in a flat surface state, next, a test piece combining a wood-based sound absorbing material and a porous sound absorbing material (GW) is used to obtain sound absorbing characteristics in a curved surface state. Was measured.
FIG. 3-1 is an explanatory view showing the test conditions of the test body (curved surface state) of the wood-based sound absorbing material of the present invention, and shows a table summarizing the curvature and cross-sectional conditions of the test body and a perspective view showing the installation status of the sound absorbing material. Consists of. Further, FIG. 3-2 is a cross-sectional view showing the configuration of each test body (No. 5 to 10) used in the sound absorption coefficient measurement test. As shown in these, in this test, No. 1 was determined based on the conditions of the magnitude of the curvature of the curved surface (three stages of large, medium, and small) and the thickness of the GW (25 mm, 50 mm) provided as the back sound absorbing layer. A total of 6 points, 5 to 10, were tested. In addition, the GW was provided in a state of being in contact with the back of the wood-based sound absorbing material. The sample area was 5.28 m 2 , which was the same as the test in the flat state. Both sides of the test piece were closed.

図3−3は、各試験体(曲面状態)の吸音率測定結果を示すグラフである。図2−3に示した平面状態の試験体No.4と比較すると、本試験の試験体No.5〜10はいずれも、250〜1000Hzの周波数帯域すなわち中高音域の範囲で、ほぼ同レベルの吸音率が幅広い周波数帯域に亘って示され、幅広い吸音特性を有していることが確認された。これは、木質系吸音材が曲面を構成していることによって、背後空気層の厚さが平面の場合よりも増したことによるものと考えられる。 FIG. 3-3 is a graph showing the sound absorption coefficient measurement results of each test body (curved surface state). Specimen No. in the flat state shown in FIG. 2-3. Compared with No. 4, the test piece No. of this test. It was confirmed that all of 5 to 10 have almost the same level of sound absorption coefficient over a wide frequency band in the frequency band of 250 to 1000 Hz, that is, the mid-high range, and have a wide range of sound absorption characteristics. .. It is considered that this is because the thickness of the back air layer is increased as compared with the case of the flat surface due to the curved surface of the wood-based sound absorbing material.

GW厚の比較では、曲率の大小に関わらず、より厚さのある50mmの方が25mmよりも吸音率が大きかった。GWは、背後空気層において抵抗として作用するが、かかる抵抗の大きい方が、つまり挿入されるGWは、厚くする方が吸音率を高められることが確認できた。一方、曲率半径1400mm(曲率大)、1800mm(曲率中)、2200mm(曲率大)の範囲での曲率による吸音率の差は、800Hz以下で多少見られるものの、顕著な違いは認められなかった。 In the comparison of GW thickness, the sound absorption coefficient of the thicker 50 mm was larger than that of the 25 mm regardless of the magnitude of the curvature. It was confirmed that the GW acts as a resistance in the back air layer, and that the larger the resistance, that is, the thicker the inserted GW, the higher the sound absorption coefficient. On the other hand, the difference in sound absorption coefficient due to the curvature in the range of the radius of curvature of 1400 mm (large curvature), 1800 mm (medium curvature), and 2200 mm (large curvature) was observed at 800 Hz or less, but no significant difference was observed.

GWのような多孔質吸音材単体では一般に、高音域で吸音率が高く、低中音域では低い。そのため、多孔質吸音材のみでは、人の話し声を効率的に吸音することが難しい。しかし、本発明の木質系吸音材を併せ用いることとし、その断面条件を調節することによって、低中音域にあたる250〜1000Hz帯域における有効な吸音対策となり得ることが示唆された。 A porous sound absorbing material such as GW generally has a high sound absorption coefficient in the high frequency range and a low sound absorption coefficient in the low and middle range. Therefore, it is difficult to efficiently absorb a person's voice with only a porous sound absorbing material. However, it was suggested that by using the wood-based sound absorbing material of the present invention together and adjusting the cross-sectional conditions thereof, it can be an effective sound absorption countermeasure in the 250 to 1000 Hz band corresponding to the low and middle range.

1.−3−(4) まとめ
可撓性を有する化粧材に切り込み部を設け、それによって通気性を持たせることにより、ヘルムホルツ共鳴器型の吸音特性を備えた木質系吸音材とすることができた。本発明の木質系吸音材は、その背後空気層にグラスウールを挿入することで吸音体を形成できるため、吸音材として利用できることが確認された。
1. 1. -3- (4) Summary By providing a notch in the flexible decorative material and giving it breathability, it was possible to obtain a wood-based sound absorbing material with Helmholtz resonator-type sound absorbing characteristics. .. It was confirmed that the wood-based sound absorbing material of the present invention can be used as a sound absorbing material because a sound absorbing body can be formed by inserting glass wool into the air layer behind the wood-based sound absorbing material.

また曲面状態では、250〜1000Hzの幅広い帯域で吸音性を有し、人の話し声の周波数を効率的に吸音できることが明らかとなった。さらに本吸音材は、その曲面を任意の曲率で形成できるため、音響拡散体としても利用することができる。すなわち本吸音材によれば、拡散と吸音の両方の効果を得ることができる。 Further, it has been clarified that the curved surface state has sound absorption in a wide band of 250 to 1000 Hz and can efficiently absorb the frequency of human speech. Further, since the curved surface of this sound absorbing material can be formed with an arbitrary curvature, it can also be used as an acoustic diffuser. That is, according to this sound absorbing material, both diffusion and sound absorbing effects can be obtained.

<実施例2 可撓性木質系吸音材の吸音特性_曲率および断面条件の試験>
2.−1 目的
実施例1の木質系吸音材について、さらに詳細な検討を行った。具体的には、断面条件(切り込み部寸法、空気層)の違いによる吸音特性の差異を確かめることを目的として、実験を行った。
2.−2 試験体の概要
試験体は、実施例1と同様に製作した。用いたGWも同様であり、25mmを背後吸音層として木質系吸音材の背後に挿入した。なお本試験は、木質系吸音材を平面状態にして行った。
<Example 2 Test of sound absorption characteristics_curvature and cross-sectional conditions of flexible wood-based sound absorbing material>
2. -1 Purpose The wood-based sound absorbing material of Example 1 was examined in more detail. Specifically, an experiment was conducted for the purpose of confirming the difference in sound absorption characteristics due to the difference in cross-sectional conditions (cutting portion size, air layer).
2. -2 Outline of test piece The test piece was produced in the same manner as in Example 1. The same applies to the GW used, and 25 mm was inserted behind the wood-based sound absorbing material as the back sound absorbing layer. This test was carried out with the wood-based sound absorbing material in a flat state.

2.−3 木質系吸音材の吸音特性
2.−3−(1) 測定方法
吸音率測定方法等も、実施例1と同様とした。
2. -3 Sound absorption characteristics of wood-based sound absorbing material 2. -3- (1) Measurement method The sound absorption coefficient measurement method and the like were the same as in Example 1.

2.−3−(2) 吸音率測定試験(空気層条件)の測定結果
図4は、本発明木質系吸音材の試験体(断面条件検討全般)の試験条件を示す説明図であり、試験体の断面条件をまとめた表と切り込み部の斜視図とからなる。ここに示すように本試験では、空気層(GW表面から設置面までの距離)、木質系吸音材の板厚(基本材とする木質板材料の厚さ)、および開口率(切り込み部により形成される開口部の面積割合)の各条件により、試験を行った。以下、順に説明する。
2. -3- (2) Measurement Results of Sound Absorption Rate Measurement Test (Air Layer Conditions) Fig. 4 is an explanatory diagram showing the test conditions of the test body of the wood-based sound absorbing material of the present invention (general examination of cross-sectional conditions), and is an explanatory diagram of the test body. It consists of a table summarizing the cross-sectional conditions and a perspective view of the notch. As shown here, in this test, the air layer (distance from the GW surface to the installation surface), the thickness of the wood-based sound absorbing material (thickness of the basic wood board material), and the aperture ratio (formed by the notch). The test was carried out under each condition of the area ratio of the opening to be formed). Hereinafter, they will be described in order.

図5−1は、吸音率測定試験(空気層条件)に用いた各試験体の構成を示す断面図である。ここに示すように本試験では、板厚20mm、開口率12.5%を共通とし、空気層を25、50、100mmに変えて試験した。 FIG. 5-1 is a cross-sectional view showing the configuration of each test piece used in the sound absorption coefficient measurement test (air layer condition). As shown here, in this test, the plate thickness was 20 mm and the aperture ratio was 12.5% in common, and the air layer was changed to 25, 50, and 100 mm.

図5−2は、図5−1に示す各試験体の吸音率測定結果を示すグラフである。図示するように、いずれの試験体も、300〜1000Hzの帯域において吸音率0.5以上を示し、吸音材として利用可能であることが確認された。また、吸音率のピークは、空気層25mmでは800Hz、50mmでは500Hz、100mmでは400Hzであった。ピーク形状がほぼ類似することもあり、さほどの差ではないと考えられるものの、空気層厚さによる吸音特性の違いは、吸音体や音響拡散体の設計検討において十分考慮に値することが示された。 FIG. 5-2 is a graph showing the sound absorption coefficient measurement results of each test piece shown in FIG. 5-1. As shown in the figure, it was confirmed that all the test bodies showed a sound absorption coefficient of 0.5 or more in the band of 300 to 1000 Hz and could be used as a sound absorbing material. The peak of the sound absorption coefficient was 800 Hz for the air layer 25 mm, 500 Hz for 50 mm, and 400 Hz for 100 mm. Although the peak shapes may be almost similar and it is considered that the difference is not so large, it was shown that the difference in sound absorption characteristics depending on the thickness of the air layer deserves sufficient consideration in the design study of the sound absorber and the acoustic diffuser. ..

図6−1は、吸音率測定試験(開口率条件)に用いた試験体の構成を示す断面図である。ここに示すように本試験では、板厚20mm、空気層50mmを共通とし、開口率を18.8%、12.5%、4.7%に変えて試験した。 FIG. 6-1 is a cross-sectional view showing the configuration of the test piece used in the sound absorption coefficient measurement test (aperture ratio condition). As shown here, in this test, the plate thickness was 20 mm and the air layer was 50 mm in common, and the aperture ratio was changed to 18.8%, 12.5%, and 4.7%.

図6−2は、図6−1に示す試験体の吸音率測定結果を示すグラフである。なお、図中に示した共鳴周波数の計算値fは、ここでは各試験体の開口率を用いて算出されている。図示するように、いずれの試験体も、300〜800Hzの帯域において吸音率0.5以上を示し、吸音材として利用可能であることが確認された。 FIG. 6-2 is a graph showing the results of measuring the sound absorption coefficient of the test piece shown in FIG. 6-1. The calculated value f 0 of the resonance frequency shown in the figure is calculated here using the aperture ratio of each test piece. As shown in the figure, it was confirmed that all the test bodies showed a sound absorption coefficient of 0.5 or more in the band of 300 to 800 Hz and could be used as a sound absorbing material.

より詳細に見ると、開口率18.8%および12.5%の試験体では吸音率のピークが500〜600Hz、吸音率0.5以上の帯域が300〜1000Hzであり、一方、開口率4.7%の試験体では吸音率のピークが400Hz、吸音率0.5以上の帯域が250〜800Hzであった。つまり、開口率4.7%の試験体は他の試験体と比較して、吸音ピークがより低音側にずれていることがわかった。したがって、開口率による吸音特性の違いは、吸音体や音響拡散体の設計検討において十分考慮に値することが示された。 More specifically, in the test specimens having an aperture ratio of 18.8% and 12.5%, the peak sound absorption ratio is 500 to 600 Hz, and the band having a sound absorption ratio of 0.5 or more is 300 to 1000 Hz, while the aperture ratio is 4. In the 0.7% test piece, the peak sound absorption ratio was 400 Hz, and the band with a sound absorption ratio of 0.5 or more was 250 to 800 Hz. That is, it was found that the sound absorption peak of the test body having an aperture ratio of 4.7% was shifted to the bass side as compared with the other test bodies. Therefore, it was shown that the difference in sound absorption characteristics depending on the aperture ratio deserves sufficient consideration in the design study of the sound absorber and the acoustic diffuser.

図7−1は、吸音率測定試験(板厚条件)に用いた試験体の構成を示す断面図である。ここに示すように本試験では、開口率12.5%、空気層50mmを共通とし、板厚を20mm、30mmに変えて試験した。 FIG. 7-1 is a cross-sectional view showing the configuration of the test piece used in the sound absorption coefficient measurement test (plate thickness condition). As shown here, in this test, the aperture ratio was 12.5%, the air layer was 50 mm in common, and the plate thickness was changed to 20 mm and 30 mm.

図7−2は、図7−1に示す試験体の吸音率測定結果を示すグラフである。図示するように、いずれの試験体も、300〜1000Hzの帯域において吸音率0.5以上を示し、吸音材として利用可能であることが確認された。板厚20mmの試験体では吸音ピークが600Hz、一方30mmの試験体では400Hzであり、後者がやや低音側にずれる吸音特性である傾向、あるいは前者がより広帯域の吸音特性を有する傾向がうかがえた。いずれにせよ板厚による吸音特性の違いも、吸音体や音響拡散体の設計検討において考慮し得ることが示された。 FIG. 7-2 is a graph showing the results of measuring the sound absorption coefficient of the test piece shown in FIG. 7-1. As shown in the figure, it was confirmed that all the test bodies showed a sound absorption coefficient of 0.5 or more in the band of 300 to 1000 Hz and could be used as a sound absorbing material. The sound absorption peak of the 20 mm thick test piece was 600 Hz, while that of the 30 mm test piece was 400 Hz, indicating that the latter tended to have a sound absorbing characteristic slightly shifted to the bass side, or the former tended to have a wider band sound absorbing characteristic. In any case, it was shown that the difference in sound absorbing characteristics depending on the plate thickness can be taken into consideration in the design study of the sound absorbing body and the acoustic diffuser.

本発明の可撓性吸音材、吸音体、音響拡散体、および音処理体の吸音特性設計方法によれば、変形により曲面を形成できる程度の可撓性を有する木製の吸音材を提供することができる。また、曲面を任意の曲率で作れるため、吸音体のみならず音響拡散体としても利用できる。さらに、様々な吸音特性の音処理体(吸音体や音響拡散体)を設計できる。したがって、木工分野、内装建材製造・利用分野、および関連する全分野において、産業上利用性が高い発明である。 According to the method for designing sound absorbing characteristics of a flexible sound absorbing material, a sound absorbing body, an acoustic diffuser, and a sound processing body of the present invention, a wooden sound absorbing material having flexibility enough to form a curved surface by deformation is provided. Can be done. Further, since the curved surface can be made with an arbitrary curvature, it can be used not only as a sound absorbing body but also as an acoustic diffuser. Furthermore, sound processing bodies (sound absorbing bodies and acoustic diffusers) having various sound absorbing characteristics can be designed. Therefore, it is an invention with high industrial applicability in the woodworking field, the interior building material manufacturing / utilization field, and all related fields.

0…基本材
1…板材
2…溝
3…共鳴型吸音構造(切り込み部)
4…開口部
5…可撓性吸音材
0 ... Basic material 1 ... Plate material 2 ... Groove 3 ... Resonant type sound absorbing structure (cut part)
4 ... Opening 5 ... Flexible sound absorbing material

Claims (12)

板材の表裏面に表裏交互にかつ平行に溝が複数設けられており、表裏面の少なくとも一方に共鳴型の吸音特性を有する共鳴型吸音構造が設けられており、
該共鳴型吸音構造が、一方面側において該溝と交差する方向に設けられた複数の切り込み部であることを特徴とする、可撓性吸音材。
A plurality of grooves are provided alternately and in parallel on the front and back surfaces of the plate material, and a resonance type sound absorption structure having resonance type sound absorption characteristics is provided on at least one of the front and back surfaces .
A flexible sound absorbing material, wherein the resonance type sound absorbing structure is a plurality of cut portions provided in a direction intersecting the groove on one surface side.
前記切り込み部の深さ寸法が、下記<A>に示す板底厚さ寸法よりも大きく、それにより該切り込み部の箇所には表裏面を連通する開口部が形成されていることを特徴とする、請求項に記載の可撓性吸音材。
<A> 板底厚さ = 板の厚さ ― 切り込み部と反対面の溝の深さ
The depth dimension of the cut portion is larger than the plate bottom thickness dimension shown in <A> below, whereby an opening communicating with the front and back surfaces is formed at the cut portion. , The flexible sound absorbing material according to claim 1.
<A> Plate bottom thickness = Plate thickness-Depth of the groove on the opposite surface to the notch
前記切り込み部が前記溝に直交して設けられていることを特徴とする、請求項1、2のいずれかに記載の可撓性吸音材。 The flexible sound absorbing material according to any one of claims 1 and 2 , wherein the cut portion is provided orthogonal to the groove. 前記板材が木質系であることを特徴とする、請求項1、2、3のいずれかに記載の可撓性吸音材。 The flexible sound absorbing material according to any one of claims 1, 2 and 3 , wherein the plate material is made of wood. 前記溝の構造および共鳴型吸音構造により、木の備える調湿作用および香り発散作用が高められていることを特徴とする、請求項に記載の可撓性吸音材。 The flexible sound absorbing material according to claim 4 , wherein the groove structure and the resonance type sound absorbing structure enhance the humidity control action and the scent diverging action provided by the tree. 前記板材の材料が下記<C>のいずれかであることを特徴とする、請求項4または5に記載の可撓性吸音材。
<C> スギ、アオモリヒバ、ヒノキ、カラマツ、アカマツ、針葉樹(スギ、アオモリヒバ、ヒノキ、カラマツまたはアカマツを除く。)
The flexible sound absorbing material according to claim 4 or 5 , wherein the material of the plate material is any of the following <C>.
<C> Sugi, Aomori Hiba, Hinoki, Larch, Japanese red pine, Conifer (excluding Sugi, Aomori Hiba, Japanese cypress, Japanese larch or Japanese red pine)
請求項1、2、3、4、5、6のいずれかに記載の可撓性吸音材を用いて形成されていることを特徴とする、吸音体。 A sound absorbing body, which is formed by using the flexible sound absorbing material according to any one of claims 1, 2, 3, 4, 5, and 6. 曲面をもって形成されていることを特徴とする、請求項に記載の吸音体。 The sound absorbing body according to claim 7 , wherein the sound absorbing body is formed with a curved surface. 前記可撓性吸音材の共鳴型吸音構造が設けられた面側に多孔質吸音材が設けられていることを特徴とする、請求項7または8に記載の吸音体。 The sound absorbing body according to claim 7 or 8 , wherein the porous sound absorbing material is provided on the surface side of the flexible sound absorbing material provided with the resonance type sound absorbing structure. 請求項1、2、3、4、5、6のいずれかに記載の可撓性吸音材を用いて形成されていることを特徴とする、音響拡散体。 An acoustic diffuser, which is formed by using the flexible sound absorbing material according to any one of claims 1, 2, 3, 4, 5, and 6. 前記可撓性吸音材の共鳴型吸音構造が設けられた面側に多孔質吸音材が設けられていることを特徴とする、請求項10に記載の音響拡散体。 The acoustic diffuser according to claim 10 , wherein a porous sound absorbing material is provided on the surface side of the flexible sound absorbing material provided with a resonance type sound absorbing structure. 請求項7、8、9のいずれかに記載の吸音体、または請求項10、11のいずれかに記載の音響拡散体(以下、合わせて「音処理体」ともいう)における吸音特性を設計する方法であって、下記<P>記載の少なくともいずれかを変化させることを特徴とする、音処理体の吸音特性設計方法。
<P> 前記可撓性吸音材の板厚、開口率(前記開口部が該可撓性吸音材の表面面積に占める割合)、空気層厚さ(前記多孔質吸音材の厚さを含む)
Design the sound absorbing characteristics of the sound absorbing body according to any one of claims 7, 8 and 9 or the acoustic diffuser according to any one of claims 10 and 11 (hereinafter, collectively referred to as "sound processing body"). A method for designing sound absorption characteristics of a sound processor, which comprises changing at least one of the methods described in <P> below.
<P> Plate thickness of the flexible sound absorbing material, aperture ratio (ratio of the opening to the surface area of the flexible sound absorbing material), air layer thickness (including the thickness of the porous sound absorbing material).
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