JP7474187B2 - Sound absorbing structure - Google Patents
Sound absorbing structure Download PDFInfo
- Publication number
- JP7474187B2 JP7474187B2 JP2020207658A JP2020207658A JP7474187B2 JP 7474187 B2 JP7474187 B2 JP 7474187B2 JP 2020207658 A JP2020207658 A JP 2020207658A JP 2020207658 A JP2020207658 A JP 2020207658A JP 7474187 B2 JP7474187 B2 JP 7474187B2
- Authority
- JP
- Japan
- Prior art keywords
- sound absorbing
- box
- absorbing structure
- shaped member
- sound
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000000463 material Substances 0.000 claims description 64
- 238000004891 communication Methods 0.000 claims description 21
- 239000002657 fibrous material Substances 0.000 claims description 8
- 229920002678 cellulose Polymers 0.000 claims description 7
- 239000001913 cellulose Substances 0.000 claims description 7
- 239000000835 fiber Substances 0.000 claims description 6
- 238000005452 bending Methods 0.000 description 23
- 230000000694 effects Effects 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 14
- 238000010521 absorption reaction Methods 0.000 description 11
- 238000005192 partition Methods 0.000 description 11
- 239000004677 Nylon Substances 0.000 description 7
- 230000002238 attenuated effect Effects 0.000 description 7
- 229920001778 nylon Polymers 0.000 description 7
- 230000003595 spectral effect Effects 0.000 description 6
- 238000012360 testing method Methods 0.000 description 4
- 229920003043 Cellulose fiber Polymers 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 3
- 238000009530 blood pressure measurement Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000010893 paper waste Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000009420 retrofitting Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Description
本発明は、吸音構造体に関し、より詳しくは、ヘルムホルツ共鳴を利用した吸音構造体に関する。 The present invention relates to a sound absorbing structure, and more specifically to a sound absorbing structure that utilizes Helmholtz resonance.
従来から、騒音対策として、ヘルムホルツ共鳴を利用した吸音構造体が、車両や建築物等の各種構造体に設置されている。 Conventionally, sound-absorbing structures that utilize Helmholtz resonance have been installed in various structures such as vehicles and buildings as a noise countermeasure.
例えば、特開２０２０－５００３８号公報（特許文献１）には、中空の凸部と、前記凸部の内外を連通する連通部とを備える吸遮音部材が開示されており、この吸遮音部材において、前記凸部は、複数のセルロース系繊維が積層状態で一体化されている素材で構成されているとともに、前記セルロース系繊維が所定の厚みで積層されている一般部位と、前記一般部位よりも多量の前記セルロース系繊維が積層されている肉厚部位とを一体で有し、前記肉厚部位によって前記連通部の外径が形成されているとともに、前記連通部には、前記肉厚部位を厚み方向に貫通して前記凸部の内外を連通する通路部が設けられていることが記載されている。 For example, JP 2020-50038 A (Patent Document 1) discloses a sound absorbing and insulating member having a hollow protrusion and a communication part that communicates the inside and outside of the protrusion. In this sound absorbing and insulating member, the protrusion is made of a material in which a plurality of cellulosic fibers are integrated in a laminated state, and has an integrated general part in which the cellulosic fibers are laminated to a predetermined thickness and a thick part in which a larger amount of the cellulosic fibers are laminated than in the general part, the outer diameter of the communication part is formed by the thick part, and the communication part is provided with a passage part that penetrates the thick part in the thickness direction and communicates the inside and outside of the protrusion.
また、特開２０２０－５２１３９号公報（特許文献２）には、吸遮音部材と、前記吸遮音部材と第一の音源の間に設けられた第一区画部材と、前記記吸遮音部材と第二の音源の間に設けられた第二画部材とを備えた吸遮音構造が開示されており、この吸遮音構造におい、前記吸遮音部材は、前記第一区画部材と前記第二画部材とを交互に当接するように曲げ形成されている板状部材であって、両区画部材の間の隙を埋めるように突出している中空の凸部を複数有し、前記第一区画部材と前記第二画部材との間には、前記第一区画部材で閉塞された前記凸部内の第一空間部と、隣り合う凸部同士の間に設けられ且つ前記第二画部材で閉塞された第二空間部とが形成されており、前記第一空間部と前記第二空間部は、前記凸部の一部で形成され且つ前記凸部の内外を連通する連通部にてつながっており、前記連通部の第二空間部側の開口は、前記第一区画部材と前記第二画部材の間に配置する前記凸部の側壁部に設けられていることが記載されている。 In addition, Japanese Patent Application Laid-Open No. 2020-52139 (Patent Document 2) discloses a sound absorbing and insulating structure including a sound absorbing and insulating member, a first partition member provided between the sound absorbing and insulating member and a first sound source, and a second partition member provided between the sound absorbing and insulating member and a second sound source. In this sound absorbing and insulating structure, the sound absorbing and insulating member is a plate-shaped member that is bent so as to alternately abut the first partition member and the second partition member, and has a plurality of hollow protrusions that protrude so as to fill the gap between the two partition members. Between the partition member and the second partition member, a first space portion within the convex portion that is blocked by the first partition member, and a second space portion that is provided between adjacent convex portions and blocked by the second partition member are formed, the first space portion and the second space portion are connected by a communication portion that is formed by a part of the convex portion and connects the inside and outside of the convex portion, and the opening of the communication portion on the second space portion side is provided in the side wall portion of the convex portion that is disposed between the first partition member and the second partition member.
しかしながら、ヘルムホルツ共鳴を利用した従来の吸音構造体においては、音圧ピークを分割することはできるものの、減衰させることができず、十分な吸音効果が得られない場合があった。 However, in conventional sound-absorbing structures that use Helmholtz resonance, although it is possible to divide sound pressure peaks, it is not possible to attenuate them, and there are cases in which a sufficient sound absorption effect cannot be obtained.
本発明は、上記従来技術の有する課題に鑑みてなされたものであり、音圧ピークを減衰させることができ、優れた吸音効果を発揮することが可能な吸音構造体を提供することを目的とする。 The present invention was made in consideration of the problems with the above-mentioned conventional technology, and aims to provide a sound-absorbing structure that can attenuate sound pressure peaks and exhibit excellent sound-absorbing effects.
本発明者らは、上記目的を達成すべく鋭意研究を重ねた結果、開口部を有する箱状部材と前記開口部を閉塞するように配置された蓋材とを備える吸音構造体において、前記箱状部材の前記開口部に対向する面に所定の大きさの連通孔を形成し、前記箱状部材をセルロース系繊維材料により形成し、前記蓋材として所定の曲げ剛性を有する素材を用いることによって、音圧ピークを減衰させることが可能となり、優れた吸音効果が発揮されることを見出し、本発明を完成するに至った。 As a result of intensive research by the inventors to achieve the above object, they discovered that in a sound absorbing structure comprising a box-shaped member having an opening and a lid material arranged to close the opening, by forming a communicating hole of a predetermined size on the surface of the box-shaped member facing the opening, forming the box-shaped member from a cellulose fiber material, and using a material having a predetermined bending rigidity for the lid material, it is possible to attenuate sound pressure peaks and achieve an excellent sound absorbing effect, which led to the completion of the present invention.
すなわち、本発明の吸音構造体は、開口部を有する箱状部材と前記開口部を閉塞するように配置された蓋材とを備えており、前記箱状部材の内側には、前記箱状部材と前記蓋材とによって囲まれた副気室空間が形成されており、前記箱状部材の前記開口部に対向する面には、前記箱状部材の内側と外側とが連通するように直径２ｍｍ以下の連通孔が形成されており、前記箱状部材がセルロース系繊維材料からなるものであり、前記蓋材の曲げ剛性が１３．８～１５０Ｎｍである、ことを特徴とするものである。 That is, the sound absorbing structure of the present invention comprises a box-shaped member having an opening and a lid material arranged to close the opening, an auxiliary air chamber space surrounded by the box-shaped member and the lid material is formed inside the box-shaped member, a communication hole having a diameter of 2 mm or less is formed on the surface of the box-shaped member facing the opening so as to connect the inside and outside of the box-shaped member, the box-shaped member is made of a cellulose-based fiber material, and the flexural rigidity of the lid material is 13.8 to 150 Nm.
本発明の吸音構造体においては、前記箱状部材が、セルロース系繊維が積層されて一体化したものであることが好ましく、また、１つの前記箱状部材と１つの前記蓋材とが１つの前記副気室空間を形成していることは好ましい。 In the sound absorbing structure of the present invention, it is preferable that the box-shaped member is made of cellulosic fibers laminated and integrated together, and it is also preferable that one box-shaped member and one lid member form one sub-air chamber space.
本発明によれば、音圧ピークを減衰させることができ、優れた吸音効果を発揮することが可能な吸音構造体を得ることが可能となる。 The present invention makes it possible to obtain a sound absorbing structure that can attenuate sound pressure peaks and provide excellent sound absorbing effects.
以下、図面を参照しながら本発明の好適な実施形態について詳細に説明するが、本発明は前記図面に限定されるものではない。なお、以下の説明及び図面中、同一又は相当する要素には同一の符号を付し、重複する説明は省略する場合もある。 The following describes in detail preferred embodiments of the present invention with reference to the drawings, but the present invention is not limited to the drawings. In the following description and drawings, the same or corresponding elements are denoted by the same reference numerals, and duplicate descriptions may be omitted.
図１に、本発明の吸音構造体の好適な一実施態様を示す。本発明の吸音構造体１０は、開口部を有する箱状部材１１と前記開口部を閉塞するように配置された蓋材１２とを備えるものである。 Figure 1 shows a preferred embodiment of the sound absorbing structure of the present invention. The sound absorbing structure 10 of the present invention comprises a box-shaped member 11 having an opening and a lid material 12 arranged to close the opening.
〔箱状部材〕
本発明に用いられる箱状部材１１は、４つの側壁部と１つの天井壁部とから形成されており、底面が開口部であり、内部が空洞である。前記箱状部材１１の形状としては特に制限はなく、例えば、図１に示すような四角錐台のほか、立方体や直方体であってもよい。
[Box-shaped member]
The box-shaped member 11 used in the present invention is formed of four side walls and one ceiling wall, has an opening at the bottom, and is hollow inside. There are no particular limitations on the shape of the box-shaped member 11, and it may be, for example, a truncated quadrangular pyramid as shown in Fig. 1, or a cube or rectangular parallelepiped.
また、本発明に用いられる箱状部材は、セルロース系繊維材料からなるものである（すなわち、前記側壁部及び前記天井壁部がセルロース系繊維材料からなるものである）ことが必要であり、セルロース系繊維が積層されて一体化したもの（例えば、パルプモールド成形品）であることが好ましい。このようなセルロース系繊維材料からなる箱状部材を用いることによって、箱状部材の内壁と空気との間の摩擦抵抗が大きくなるため、音圧ピークの減衰量が増大して吸音性能が向上するとともに、吸音構造体を軽量化することが可能となる。 The box-shaped member used in the present invention must be made of a cellulosic fiber material (i.e., the side wall portion and the ceiling wall portion must be made of a cellulosic fiber material), and is preferably made of laminated cellulosic fibers (e.g., a pulp molded product). By using a box-shaped member made of such a cellulosic fiber material, the frictional resistance between the inner wall of the box-shaped member and the air increases, so that the attenuation of the sound pressure peak increases, improving the sound absorption performance and making it possible to reduce the weight of the sound absorbing structure.
さらに、本発明に用いられる箱状部材１１においては、図１に示すように、前記開口部に対向する面１３（すなわち、前記天井壁部）に、箱状部材１１の内側と外側とが連通するように連通孔１４が形成されていることが必要である。このような連通孔１４は、前記開口部に対向する面１３（すなわち、前記天井壁部）の中央部に形成されていることが好ましいが、これに限定されるものではない。 Furthermore, in the box-shaped member 11 used in the present invention, as shown in FIG. 1, it is necessary that a communication hole 14 is formed in the surface 13 (i.e., the ceiling wall portion) facing the opening so that the inside and outside of the box-shaped member 11 are in communication. It is preferable that such a communication hole 14 is formed in the center of the surface 13 (i.e., the ceiling wall portion) facing the opening, but this is not limited to this.
また、本発明に用いられる箱状部材においては、前記連通孔の直径が２ｍｍ以下であることが必要である。連通孔の直径を前記範囲内とすることによって、音圧ピークが十分に減衰され、優れた吸音効果が発揮される。一方、連通孔の直径が前記上限を超えると、音圧ピークは分割するものの、減衰せず、吸音効果が得られない。さらに、前記連通孔の直径としては、音圧ピークの減衰量が増大し、吸音効果が向上するという観点から、１．５ｍｍ以下が好ましく、１．２ｍｍ以下がより好ましく、１．０ｍｍ以下が特に好ましい。また、前記連通孔の直径の下限としては特に制限はないが、生産時の歩留りが向上するという観点から、０．１ｍｍ以上が好ましく、０．５ｍｍ以上がより好ましく、０．８ｍｍ以上が特に好ましい。 In addition, in the box-shaped member used in the present invention, the diameter of the communicating hole must be 2 mm or less. By setting the diameter of the communicating hole within the above range, the sound pressure peak is sufficiently attenuated, and an excellent sound absorption effect is exhibited. On the other hand, if the diameter of the communicating hole exceeds the above upper limit, the sound pressure peak is divided but not attenuated, and no sound absorption effect is obtained. Furthermore, the diameter of the communicating hole is preferably 1.5 mm or less, more preferably 1.2 mm or less, and particularly preferably 1.0 mm or less, from the viewpoint of increasing the attenuation of the sound pressure peak and improving the sound absorption effect. In addition, there is no particular restriction on the lower limit of the diameter of the communicating hole, but from the viewpoint of improving the yield during production, it is preferably 0.1 mm or more, more preferably 0.5 mm or more, and particularly preferably 0.8 mm or more.
前記箱状部材を構成する前記側壁部及び前記天井壁部の厚さとしては特に制限はないが、吸音構造体の強度を確保するという観点から、１．０～３．０ｍｍが好ましく、１．５～２．５ｍｍがより好ましい。 There are no particular limitations on the thickness of the side walls and the ceiling wall that make up the box-shaped member, but from the perspective of ensuring the strength of the sound absorbing structure, a thickness of 1.0 to 3.0 mm is preferable, and 1.5 to 2.5 mm is even more preferable.
〔蓋材〕
本発明に用いられる蓋材は、５．０～１５０Ｎｍの範囲内の曲げ剛性を有する板状部材である。前記範囲内の曲げ剛性を有する蓋材を用いることによって、音圧ピークが十分に減衰され、優れた吸音効果が発揮される。一方、蓋材の曲げ剛性が前記下限未満になると、音圧ピークが減衰せず、吸音効果が得られない。また、蓋材の曲げ剛性としては、１０～１２０Ｎｍが好ましく、５０～１００Ｎｍがより好ましい。なお、蓋材の曲げ剛性は、蓋材に使用した材料のヤング率Ｅ及びポアソン比ν、蓋材の厚さｔを用いて、下記式：
Ｄ＝Ｅｔ３／［１２（１－ν２）］
により求めることができる。
[Covering material]
The lid material used in the present invention is a plate-like member having a bending rigidity in the range of 5.0 to 150 Nm. By using a lid material having a bending rigidity within this range, sound pressure peaks are sufficiently attenuated and an excellent sound absorbing effect is exhibited. On the other hand, if the bending rigidity of the lid material is less than the lower limit, sound pressure peaks are not attenuated and no sound absorbing effect is obtained. The bending rigidity of the lid material is preferably 10 to 120 Nm, and more preferably 50 to 100 Nm. The bending rigidity of the lid material is calculated by the following formula using the Young's modulus E and Poisson's ratio ν of the material used for the lid material and the thickness t of the lid material:
D = Et3 /[12(1- v2 )]
It can be calculated by:
前記蓋材に使用する材料としては特に制限はなく、例えば、鋼（ヤング率Ｅ＝２０６ＧＰａ、ポアソン比ν＝０．２９）、セルロース（ヤング率Ｅ＝２０ＧＰａ、ポアソン比ν＝０．１９）、ナイロン（ヤング率Ｅ＝５．９ＧＰａ、ポアソン比ν＝０．３８）等が挙げられる。 There are no particular limitations on the material used for the lid, and examples include steel (Young's modulus E = 206 GPa, Poisson's ratio ν = 0.29), cellulose (Young's modulus E = 20 GPa, Poisson's ratio ν = 0.19), and nylon (Young's modulus E = 5.9 GPa, Poisson's ratio ν = 0.38).
また、前記蓋材の厚さとしては、蓋材の材料が鋼の場合には０．７～２ｍｍが好ましく、０．９～１．４ｍｍがより好ましく、セルロースの場合には１．５～２０ｍｍが好ましく、１．９～５．０ｍｍがより好ましく、ナイロンの場合には２．１～２０ｍｍが好ましく、２．５～１０ｍｍがより好ましい。蓋材の厚さが前記範囲内にあると、蓋材の曲げ剛性が所定の範囲内となる。一方、蓋材の厚さが前記下限未満になると、蓋材の曲げ剛性が所定の範囲より小さくなり、音圧ピークが減衰せず、吸音効果が得られない傾向にあり、他方、前記上限を超えると、吸音構造体の取扱性が低下する傾向にある。 The thickness of the lid material is preferably 0.7 to 2 mm, more preferably 0.9 to 1.4 mm, when the lid material is steel, preferably 1.5 to 20 mm, more preferably 1.9 to 5.0 mm, when the lid material is cellulose, and preferably 2.1 to 20 mm, more preferably 2.5 to 10 mm, when the lid material is nylon. When the thickness of the lid material is within the above range, the bending rigidity of the lid material is within a specified range. On the other hand, when the thickness of the lid material is less than the lower limit, the bending rigidity of the lid material is smaller than the specified range, the sound pressure peak is not attenuated, and the sound absorption effect tends not to be obtained, and on the other hand, when the thickness of the lid material exceeds the upper limit, the handleability of the sound absorbing structure tends to decrease.
さらに、前記蓋材の密度としては、蓋材の材料が鋼の場合には７３００～７９００ｋｇ／ｍ３が好ましく、セルロースの場合には１２００～１７００ｋｇ／ｍ３が好ましく、ナイロンの場合には１１００～１４００ｋｇ／ｍ３が好ましい。蓋材の密度が前記範囲内にあると、ヘルムホルツ共鳴による吸音効果が十分に発現する。一方、蓋材の密度が前記下限未満になると、蓋材の曲げ剛性が低下して吸音効果が低下する傾向にある。 Furthermore, the density of the lid material is preferably 7300 to 7900 kg/ m3 when the material is steel, 1200 to 1700 kg/ m3 when the material is cellulose, and 1100 to 1400 kg/ m3 when the material is nylon. When the density of the lid material is within the above range, the sound absorbing effect due to Helmholtz resonance is fully exhibited. On the other hand, when the density of the lid material is below the lower limit, the bending rigidity of the lid material decreases, and the sound absorbing effect tends to decrease.
〔吸音構造体〕
図１に示すように、本発明の吸音構造体１０は、前記箱状部材１１と前記蓋材１２とを備えるものである。また、本発明の吸音構造体１０においては、図２に示すように、前記箱状部材１１の内側に、前記箱状部材１１と前記蓋材１２とによって囲まれた副気室空間２１が形成されている。特に、本発明の吸音構造体１０においては、１つの前記箱状部材１１と１つの前記蓋材１２とが１つの副気室空間２１を形成している。このような副気室空間の容積としては３７００～３００００ｍｍ３が好ましい。
[Sound absorbing structure]
As shown in Fig. 1, the sound absorbing structure 10 of the present invention comprises the box-shaped member 11 and the lid material 12. In addition, in the sound absorbing structure 10 of the present invention, an auxiliary air chamber space 21 surrounded by the box-shaped member 11 and the lid material 12 is formed inside the box-shaped member 11 as shown in Fig. 2. In particular, in the sound absorbing structure 10 of the present invention, one box-shaped member 11 and one lid material 12 form one auxiliary air chamber space 21. The volume of such an auxiliary air chamber space is preferably 3700 to 30000 mm3 .
本発明の吸音構造体１０においては、曲げ剛性が大きい蓋材１２を用いているため、図２に示すように、副気室空間２１が変形しにくく、副気室空間２１内の空気がバネとしての役割を有し、質量としての役割を有する連通孔１４内の空気が振動することによって、バネ－マス１自由度振動系を形成し、下記式：
ｆ＝（ｃ／２π）（Ｓ／Ｖ（Ｌ＋ｈａ））１／２
〔式中、ｆは固有振動数、ａは連通孔の半径、Ｓは連通孔の断面積（＝πａ２）、Ｌは連通孔の長さ（＝前記天井壁部の厚さ）、Ｖは副気室空間の容積、ｃは音速、ｈは開口端補正係数（０．６～２．０）を表す、〕
で表される固有振動数ｆで副気室空間２１内が共鳴し、吸音構造体１０を設置した空間の共鳴時の音圧が低減され、吸音効果が得られる。
In the sound absorbing structure 10 of the present invention, since the lid material 12 having a large bending rigidity is used, as shown in FIG. 2, the sub air chamber space 21 is difficult to deform, and the air in the sub air chamber space 21 acts as a spring, and the air in the communication hole 14 acting as a mass vibrates, forming a spring-mass one degree of freedom vibration system, and the following formula:
f = (c/2π) (S/V(L+ha)) 1/2
(wherein f is the natural frequency, a is the radius of the communication hole, S is the cross-sectional area of the communication hole (=πa 2 ), L is the length of the communication hole (= the thickness of the ceiling wall portion), V is the volume of the sub-air chamber space, c is the sound speed, and h is the open end correction coefficient (0.6 to 2.0).)
The sound pressure at the time of resonance in the space in which the sound absorbing structure 10 is installed is reduced, and a sound absorbing effect is obtained.
一方、曲げ剛性が小さい蓋材を用いた場合には、図３に示すように、副気室空間２１が変形するため、連通孔１４内の空気の振動に対する復元力が得られず、副気室空間２１内の空気がバネとして作用しない。このため、副気室空間２１内では共鳴が起こらず、吸音構造体１０を設置した空間の音圧が低減されず、吸音効果が得られない。 On the other hand, if a lid material with low bending rigidity is used, as shown in FIG. 3, the sub-air chamber space 21 deforms, and no restoring force is obtained against the vibration of the air in the communication hole 14, and the air in the sub-air chamber space 21 does not act as a spring. As a result, no resonance occurs in the sub-air chamber space 21, the sound pressure in the space in which the sound-absorbing structure 10 is installed is not reduced, and no sound-absorbing effect is obtained.
また、本発明の吸音構造体においては、上述したように、前記式で表される固有振動数ｆで副気室空間内が共鳴するため、連通孔の半径ａ、連通孔の長さＬ、副気室空間の容積Ｖを適宜調整することによって、任意の周波数の騒音を低減することができる。特に、本発明の吸音構造体においては、一般的な吸音材により吸音することが困難な低周波（２０～１０００Ｈｚ）の騒音を低減することが可能である。 In addition, in the sound absorbing structure of the present invention, as described above, the sub-air chamber space resonates at the natural frequency f expressed by the above formula, so noise of any frequency can be reduced by appropriately adjusting the radius a of the communication hole, the length L of the communication hole, and the volume V of the sub-air chamber space. In particular, the sound absorbing structure of the present invention can reduce low-frequency (20 to 1000 Hz) noise that is difficult to absorb with general sound absorbing materials.
本発明の吸音構造体においては、１つの吸音構造体に１つの副気室空間が形成されているため、吸音が必要な場所に必要な数の吸音構造体を最適に設置することができ、ロバストな効果と効率的な配置によって吸音効果を得ることが可能である。 In the sound absorbing structure of the present invention, one sub-air chamber space is formed in each sound absorbing structure, so the required number of sound absorbing structures can be optimally installed in the places where sound absorption is required, and a sound absorbing effect can be obtained through robust effect and efficient arrangement.
本発明の吸音構造体は、吸音器として独立している（すなわち、他の構造体に組込まれていない）ため、自動車や建築物等の様々な構造体の任意の位置（例えば、自動車の車室内の天井部（特に、天井外板と内装材との間）や建築物の室内の天井部（天井の裏側）等）に公知の固定（接着）手段によって設置することができる。このため、本発明の吸音構造体においては、前記蓋材の裏面に両面テープやシール材層、接着剤層、面ファスナー等が設けられていてもよい。 The sound absorbing structure of the present invention is an independent sound absorber (i.e., not incorporated into another structure), and therefore can be installed at any position of various structures such as automobiles and buildings (for example, the ceiling part of the passenger compartment of an automobile (particularly between the outer ceiling panel and the interior material) or the ceiling part of the interior of a building (the back side of the ceiling), etc.) by known fixing (adhesion) means. For this reason, in the sound absorbing structure of the present invention, double-sided tape, a sealant layer, an adhesive layer, a hook-and-loop fastener, etc. may be provided on the back side of the lid material.
また、本発明の吸音構造体は、サイズが小さく、軽量であるため、自動車内装材の隙間等の小スペースにも設置することが可能である。 In addition, the sound absorbing structure of the present invention is small in size and lightweight, so it can be installed in small spaces such as gaps in automobile interior materials.
さらに、本発明の吸音構造体は、吸音器として独立しているため、例えば、自動車の内装材組立時に取付けたり、或いは、自動車の内装材を取外して（すなわち、後付けで）取付けることも可能である。 Furthermore, since the sound absorbing structure of the present invention is an independent sound absorber, it can be installed, for example, when assembling the interior materials of the automobile, or it can be installed after removing the interior materials of the automobile (i.e., retrofitting).
以下、実施例及び比較例に基づいて本発明をより具体的に説明するが、本発明は以下の実施例に限定されるものではない。なお、蓋材の合成は下記式に基づいて算出した。 The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples. The composition of the lid material was calculated based on the following formula.
＜蓋材の曲げ剛性＞
Ｄ＝Ｅｔ３／［１２（１－ν２）］
式中、Ｅはヤング率を表し、セルロース繊維材料ではＥ＝２０ＧＰａであり、ナイロンではＥ＝５．９ＧＰａであり、νはポアソン比を表し、セルロース繊維材料ではν＝０．１９であり、ナイロンではν＝０．３８であり、ｔは蓋材の厚さを表す。
<Bending rigidity of lid material>
D = Et3 /[12(1- v2 )]
In the formula, E represents Young's modulus, where E = 20 GPa for cellulose fiber material and E = 5.9 GPa for nylon, v represents Poisson's ratio, where v = 0.19 for cellulose fiber material and v = 0.38 for nylon, and t represents the thickness of the lid material.
（実施例１）
図１に示すような、連通孔１４を有する箱状部材１１と蓋材１２とからなる吸音構造体１０を作製した。具体的には、先ず、所定量の古紙パルプを水に投入してスラリーを調製し、このスラリーを用いてパルプモールド成形により、箱状部材１１（Ｌ１＝７０ｍｍ、Ｄ１＝２５ｍｍ、Ｌ２＝６５ｍｍ、Ｄ２＝２０ｍｍ、側壁部及び天井壁部の厚さ＝２．０ｍｍ）を作製した。また、図１に示すように、箱状部材１１の開口部に対向する面１３（すなわち、天井壁部）の中央部には直径０．９７ｍｍの連通孔１４を形成した。
Example 1
As shown in Fig. 1, a sound absorbing structure 10 was produced, which was composed of a box-shaped member 11 having a communication hole 14 and a lid member 12. Specifically, a predetermined amount of waste paper pulp was first put into water to prepare a slurry, and the slurry was used to produce a box-shaped member 11 ( L1 = 70 mm, D1 = 25 mm, L2 = 65 mm, D2 = 20 mm, thickness of side wall and ceiling wall = 2.0 mm) by pulp molding. Also, as shown in Fig. 1, a communication hole 14 having a diameter of 0.97 mm was formed in the center of a surface 13 (i.e., the ceiling wall) facing the opening of the box-shaped member 11.
次に、このようにして作製した箱状部材１１に、蓋材１２としてナイロン製固定板（厚さ＝５ｍｍ、曲げ剛性：７１．８Ｎｍ）を、箱状部材１１の開口部を閉塞するように接着し、図４に示す吸音構造体を作製した。 Next, a nylon fixing plate (thickness = 5 mm, bending stiffness: 71.8 Nm) was attached as a lid material 12 to the box-shaped member 11 thus produced so as to close the opening of the box-shaped member 11, producing the sound-absorbing structure shown in Figure 4.
（比較例１）
蓋材としてナイロン製固定板（厚さ＝２．１ｍｍ、曲げ剛性：５．３Ｎｍ）を用いた以外は実施例１と同様にして吸音構造体を作製した。
( Comparative Example 1 )
A sound absorbing structure was produced in the same manner as in Example 1, except that a nylon fixing plate (thickness = 2.1 mm, bending rigidity: 5.3 Nm) was used as the lid material.
（実施例２）
蓋材としてセルロース製固定板（厚さ＝２．０ｍｍ、曲げ剛性：１３．８Ｎｍ）を用いた以外は実施例１と同様にして吸音構造体を作製した。
Example 2
A sound absorbing structure was produced in the same manner as in Example 1, except that a cellulose fixing plate (thickness = 2.0 mm, bending rigidity: 13.8 Nm) was used as the lid material.
（比較例２）
蓋材としてセルロース製固定板（厚さ＝１．４ｍｍ、曲げ剛性：４．７Ｎｍ）を用いた以外は実施例１と同様にして吸音構造体を作製した。
(Comparative Example 2 )
A sound absorbing structure was produced in the same manner as in Example 1, except that a cellulose fixing plate (thickness = 1.4 mm, bending rigidity: 4.7 Nm) was used as the lid material.
（比較例３）
連通孔１４の直径を２．２ｍｍに変更した以外は実施例１と同様にして吸音構造体を作製した。
(Comparative Example 3 )
A sound absorbing structure was produced in the same manner as in Example 1, except that the diameter of the communicating hole 14 was changed to 2.2 mm.
〔吸音試験〕
図５に示すように、作製した吸音構造体の蓋材裏面５１に面ファスナー（マジックテープ（登録商標））のフック側５２を接着した。この面ファスナーのフックを利用して、図６に示すように、９６個の吸音構造体１０を自動車（５人乗りハッチバック）の車室内天井のファブリック製内装材に装着した。
[Sound absorption test]
As shown in Fig. 5, a hook side 52 of a hook-and-loop fastener (Magic Tape (registered trademark)) was attached to the back surface 51 of the lid material of the produced sound absorbing structure. Using the hook-and-loop fastener hooks, 96 sound absorbing structures 10 were attached to a fabric interior material on the passenger compartment ceiling of an automobile (a five-seater hatchback) as shown in Fig. 6.
自動車を時速３０ｋｍ（スピードメーターの読取り値）の一定速度で直進させ、走行中、１秒間の音圧計測を連続して５回実施した（計測中の走行距離：約４２ｍ）。具体的には、自動車走行時の車室内の音圧を、図６に示すように左前席のヘッドレストの右側に取付けたマイクロホン６１を用いて計測し、得られた計測信号を、ラゲッジルームに搭載した多チャンネルＦＦＴアナライザを用いて、表１に示すサンプリング周波数で表１に示す上限周波数までサンプリングし、得られたデータを、窓関数としてハニングウィンドウを用いて解析した。この走行試験を３回実施し、合計１５回の音圧計測データを平均した。図７～図１１は、実施例１～２及び比較例１～３で作製した吸音構造体を装着した場合の各周波数における音圧パワースペクトル密度（合計１５回の音圧計測の平均値）を示すグラフである。なお、各グラフには吸音構造体を装着しなかった場合の結果も示した。 The car was driven straight at a constant speed of 30 km/h (speedometer reading), and sound pressure measurements were performed five times in succession for one second while the car was running (distance traveled during measurement: about 42 m). Specifically, the sound pressure in the car cabin while the car was running was measured using a microphone 61 attached to the right side of the headrest of the left front seat as shown in FIG. 6, and the obtained measurement signal was sampled using a multi-channel FFT analyzer mounted in the luggage compartment at the sampling frequency shown in Table 1 up to the upper limit frequency shown in Table 1, and the obtained data was analyzed using a Hanning window as a window function. This running test was performed three times, and a total of 15 sound pressure measurement data were averaged. FIGS. 7 to 11 are graphs showing sound pressure power spectrum density (average value of a total of 15 sound pressure measurements) at each frequency when the sound absorbing structures produced in Examples 1 to 2 and Comparative Examples 1 to 3 were installed. Note that each graph also shows the results when the sound absorbing structures were not installed.
図７及び図９に示したように、連通孔の直径が０．９７ｍｍ、蓋材の曲げ剛性が所定の範囲内にある吸音構造体を装着した場合（実施例１～２）には、周波数２３０Ｈｚ付近の音圧ピークを減衰でき、吸音効果が得られることが確認された。また、蓋材の曲げ剛性が７１．８Ｎｍの場合（実施例１）には、周波数が約２３０Ｈｚの音圧ピークを分割できることも確認された。 As shown in Figures 7 and 9, when a sound absorbing structure having a communicating hole diameter of 0.97 mm and a lid material with a bending rigidity within a predetermined range is attached (Examples 1 to 2 ), it was confirmed that the sound pressure peak near a frequency of 230 Hz can be attenuated and a sound absorbing effect can be obtained. In addition, when the lid material has a bending rigidity of 71.8 Nm (Example 1), it was also confirmed that the sound pressure peak at a frequency of about 230 Hz can be divided.
一方、図１０に示したように、蓋材の曲げ剛性が所定の範囲より小さい吸音構造体を装着した場合（比較例２）には、いずれの周波数においても音圧ピークの減衰が見られず、吸音効果が得られなかった。 On the other hand, as shown in FIG. 10, when a sound absorbing structure having a lid material with a bending rigidity smaller than the predetermined range was attached (Comparative Example 2 ), no attenuation of the sound pressure peak was observed at any frequency, and no sound absorbing effect was obtained.
また、図１１に示したように、連通孔の直径が２．２ｍｍの吸音構造体を装着した場合（比較例３）には、周波数が３８５Ｈｚ付近の音圧ピークを分割することはできたが、減衰することはできなかった。 Furthermore, as shown in FIG. 11, when a sound absorbing structure having a communicating hole diameter of 2.2 mm was installed (Comparative Example 3 ), the sound pressure peak at a frequency of about 385 Hz could be divided but could not be attenuated.
図７～図１１に示した結果に基づいて、周波数が２３０Ｈｚ付近（実施例１～２及び比較例１～２）又は３８５Ｈｚ付近（比較例３）の音圧パワースペクトル密度の減衰量（単位：ｄＢ）及び音響エネルギーの減衰量（単位：％）を求めた。それらの結果を表１に示す。 7 to 11, the attenuation (unit: dB) of the sound pressure power spectrum density and the attenuation (unit: %) of the acoustic energy were determined at frequencies around 230 Hz (Examples 1 and 2 and Comparative Examples 1 and 2 ) and around 385 Hz (Comparative Example 3 ). The results are shown in Table 1.
表１に示したように、連通孔の直径及び蓋材の曲げ剛性が所定の範囲内にある吸音構造体を装着した場合（実施例１～２）には、蓋材の曲げ剛性が所定の範囲より小さい吸音構造体を装着した場合（比較例２）並びに連通孔の直径が所定の範囲より大きい吸音構造体を装着した場合（比較例３）に比べて、吸音対象周波数における、音圧パワースペクトル密度の減衰量及び音響エネルギーの減衰量が大きく、連通孔の直径及び蓋材の曲げ剛性を所定の範囲内とすることによって、吸音効果に優れた吸音構造体が得られることがわかった。 As shown in Table 1, when a sound absorbing structure in which the diameter of the communicating hole and the bending rigidity of the lid material are within a specified range (Examples 1 to 2 ), the attenuation of the sound pressure power spectral density and the attenuation of the acoustic energy at the target frequency for sound absorption are greater than when a sound absorbing structure in which the bending rigidity of the lid material is smaller than the specified range (Comparative Example 2 ) and when a sound absorbing structure in which the diameter of the communicating hole is larger than the specified range (Comparative Example 3 ) are installed. It was found that by setting the diameter of the communicating hole and the bending rigidity of the lid material within the specified ranges, a sound absorbing structure with excellent sound absorbing effect can be obtained.
以上説明したように、本発明によれば、音圧ピークを減衰させることができ、優れた吸音効果を発揮することが可能な吸音構造体を得ることが可能となる。したがって、本発明の吸音構造体は、自動車の車室内や建築物の室内の騒音等を低減するための吸音器等として有用である。 As described above, according to the present invention, it is possible to obtain a sound absorbing structure that can attenuate sound pressure peaks and exhibit excellent sound absorbing effects. Therefore, the sound absorbing structure of the present invention is useful as a sound absorber for reducing noise, etc., inside an automobile or building.
１０：吸音構造体
１１：箱状部材
１２：蓋材
１３：箱状部材１１の開口部に対向する面
１４：連通孔
２１：副気室空間
４１：接着剤
５１：蓋材１２の裏面
５２：面ファスナー（マジックテープ（登録商標））のフック側
６１：マイクロホン
10: Sound absorbing structure 11: Box-shaped member 12: Lid material 13: Surface facing the opening of the box-shaped member 11 14: Communication hole 21: Sub-air chamber space 41: Adhesive 51: Back surface of the lid material 12 52: Hook side of hook-and-loop fastener (Magic Tape (registered trademark)) 61: Microphone
Claims (3)
前記箱状部材の内側には、前記箱状部材と前記蓋材とによって囲まれた副気室空間が形成されており、
前記箱状部材の前記開口部に対向する面には、前記箱状部材の内側と外側とが連通するように直径２ｍｍ以下の連通孔が形成されており、
前記箱状部材がセルロース系繊維材料からなるものであり、
前記蓋材の曲げ剛性が１３．８～１５０Ｎｍである、
ことを特徴とする吸音構造体。 The container includes a box-shaped member having an opening and a cover arranged to close the opening,
An auxiliary air chamber space surrounded by the box-shaped member and the lid member is formed inside the box-shaped member,
a communication hole having a diameter of 2 mm or less is formed on a surface of the box-shaped member facing the opening so that the inside and outside of the box-shaped member are in communication with each other;
The box-shaped member is made of a cellulosic fiber material,
The flexural rigidity of the cover material is 13.8 to 150 Nm.
A sound absorbing structure characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020207658A JP7474187B2 (en) | 2020-12-15 | 2020-12-15 | Sound absorbing structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020207658A JP7474187B2 (en) | 2020-12-15 | 2020-12-15 | Sound absorbing structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2022094652A JP2022094652A (en) | 2022-06-27 |
| JP7474187B2 true JP7474187B2 (en) | 2024-04-24 |
Family
ID=82162710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2020207658A Active JP7474187B2 (en) | 2020-12-15 | 2020-12-15 | Sound absorbing structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP7474187B2 (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998018657A8 (en) | 1996-10-29 | 1999-05-27 | Rieter Automotive Int Ag | Ultralight, multifunctional sound-insulating kit |
| JP2003293326A (en) | 2002-03-29 | 2003-10-15 | Toray Ind Inc | Composite panel made of fiber-reinforced plastic |
| JP2007509816A (en) | 2003-10-31 | 2007-04-19 | ダウ グローバル テクノロジーズ インコーポレイティド | Sound insulation system |
| JP2007223606A (en) | 1998-05-12 | 2007-09-06 | Rieter Automotive (Internatl) Ag | Vehicle part with acoustic effect |
| WO2018043489A1 (en) | 2016-08-31 | 2018-03-08 | 富士フイルム株式会社 | Sound-proofing structure and sound-proofing system |
| JP2020052139A (en) | 2018-09-25 | 2020-04-02 | トヨタ車体株式会社 | Sound absorbing/insulating structure |
| JP2020050038A (en) | 2018-09-25 | 2020-04-02 | トヨタ車体株式会社 | Sound absorption/insulation material and its manufacturing method |
| US20200130854A1 (en) | 2017-04-21 | 2020-04-30 | Office National D'etudes Et De Recherches Aerospatiales | Surface trim for acoustic absorption |
-
2020
- 2020-12-15 JP JP2020207658A patent/JP7474187B2/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998018657A8 (en) | 1996-10-29 | 1999-05-27 | Rieter Automotive Int Ag | Ultralight, multifunctional sound-insulating kit |
| JP2007223606A (en) | 1998-05-12 | 2007-09-06 | Rieter Automotive (Internatl) Ag | Vehicle part with acoustic effect |
| JP2003293326A (en) | 2002-03-29 | 2003-10-15 | Toray Ind Inc | Composite panel made of fiber-reinforced plastic |
| JP2007509816A (en) | 2003-10-31 | 2007-04-19 | ダウ グローバル テクノロジーズ インコーポレイティド | Sound insulation system |
| WO2018043489A1 (en) | 2016-08-31 | 2018-03-08 | 富士フイルム株式会社 | Sound-proofing structure and sound-proofing system |
| US20200130854A1 (en) | 2017-04-21 | 2020-04-30 | Office National D'etudes Et De Recherches Aerospatiales | Surface trim for acoustic absorption |
| JP2020052139A (en) | 2018-09-25 | 2020-04-02 | トヨタ車体株式会社 | Sound absorbing/insulating structure |
| JP2020050038A (en) | 2018-09-25 | 2020-04-02 | トヨタ車体株式会社 | Sound absorption/insulation material and its manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2022094652A (en) | 2022-06-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8360201B2 (en) | Sound absorbing structure and sound chamber | |
| US8091685B2 (en) | Sound absorbing structure built into luggage compartment of vehicle | |
| JP5028479B2 (en) | Bandpass box in the vehicle support structure | |
| JP6185859B2 (en) | Body panel structure | |
| KR102157758B1 (en) | Sound insulation | |
| BG103731A (en) | Loudspeakers built in passenger vehicles containing acoustic emission components having panel form | |
| JP6123886B2 (en) | Wire harness with sound absorbing material | |
| JP2009040071A (en) | Sound absorbing material, and sound absorbing structure equipped with sound absorbing material | |
| BR112012018867B1 (en) | Part of sound insulation trim with acoustic spring-mass characteristics comprising a mass layer and a layer for dissociation and use thereof | |
| EP3926621B1 (en) | Sound reflection structure | |
| JP2010504882A (en) | Soundproof components for automotive rigid structural members | |
| JP2015074358A (en) | Damping reinforcement material | |
| JP2021189212A (en) | Sound isolation system and sound isolation method | |
| JP5315861B2 (en) | Car body structure and instrument panel | |
| JP7474187B2 (en) | Sound absorbing structure | |
| EP3926622A1 (en) | Sound reflection structure | |
| JPH11217051A (en) | Interior material for automobile | |
| JPH10226283A (en) | Cab noise reduction device of car | |
| JP5228598B2 (en) | Body structure | |
| JPH10236333A (en) | Dash panel of automobile | |
| JP2009040072A (en) | Sound absorbing structure | |
| CN113212139A (en) | Battery pack structure and forming method thereof | |
| WO2023234311A1 (en) | Vehicle sound-absorbing device | |
| KR20070071989A (en) | Dash panel with absorbing and excluding function of sounds | |
| JP2003150170A (en) | Sound absorbing and vibration damping material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20210107 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20230524 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20240109 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20240117 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20240308 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20240408 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20240412 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 7474187 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |