JPH02261997A - Silencing device - Google Patents
Silencing deviceInfo
- Publication number
- JPH02261997A JPH02261997A JP1083703A JP8370389A JPH02261997A JP H02261997 A JPH02261997 A JP H02261997A JP 1083703 A JP1083703 A JP 1083703A JP 8370389 A JP8370389 A JP 8370389A JP H02261997 A JPH02261997 A JP H02261997A
- Authority
- JP
- Japan
- Prior art keywords
- speaker
- sound
- duct
- silencing
- sound source
- 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.)
- Pending
Links
- 230000030279 gene silencing Effects 0.000 title claims abstract description 18
- 230000003584 silencer Effects 0.000 claims abstract description 8
- 230000000644 propagated effect Effects 0.000 claims description 5
- 230000001902 propagating effect Effects 0.000 claims description 4
- 238000009434 installation Methods 0.000 abstract description 5
- 230000002708 enhancing effect Effects 0.000 abstract 1
- 230000002265 prevention Effects 0.000 abstract 1
- 230000005855 radiation Effects 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 3
- 230000001743 silencing effect Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Pipe Accessories (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
この発明は、ダクト状構造物内を伝播する音を採取して
、ダクト出口付近において消音用スピーカから２次音を
発生させることにより能動的に音を消滅させる消音装置
に関する。[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention collects sound propagating inside a duct-like structure and generates secondary sound from a muffling speaker near the duct exit. The present invention relates to a muffling device that actively extinguishes sound by
（従来の技術）
従来から能動制御型の消音装置上して第８図に示すよう
な装置が知られている。(Prior Art) A device as shown in FIG. 8 has been known as an active control type muffling device.
この装置は、音源１から発生された音を伝播させるダク
ト２の特定箇所に集音マイク３を設置すると共に、ダク
ト２の出口付近に消音用スピーカ４を設置し、これら集
音マイク３と消音用スピーカ４とを信号変換回路５を介
して接続して構成されている。This device installs a sound collection microphone 3 at a specific location of a duct 2 that propagates the sound generated from a sound source 1, and also installs a noise-reducing speaker 4 near the exit of the duct 2. A speaker 4 is connected to the signal conversion circuit 5 via a signal conversion circuit 5.
音源１から発せられた音はダクト２の寸法で決まる低周
波の範囲では平面波としてダクト２内を伝播し、集音マ
イク３により採取される。採取された電気信号は信号変
換回路５により位相反転されて消音用スピーカ４に供給
される。この結果、消音用スピーカ４から消音のための
２次音が発生され、この２次音が音源１からの音と干渉
することによって消音される。The sound emitted from the sound source 1 propagates in the duct 2 as a plane wave in the low frequency range determined by the dimensions of the duct 2, and is collected by the sound collection microphone 3. The phase of the sampled electrical signal is inverted by the signal conversion circuit 5 and then supplied to the silencing speaker 4. As a result, a secondary sound for silencing is generated from the silencing speaker 4, and this secondary sound is muted by interfering with the sound from the sound source 1.
ところで、このような消音装置において、消音用スピー
カ４は消音しようとする音の周波数によって最適な形状
が決定される。即ち、一般に低周波領域では、スピーカ
の放射効率が悪化するので、これを防止するために可能
な限り径の大きなスピーカを使用する必要があるが、実
際には設置空間の関係上、そのような大型のスピーカを
使用することは不可能であった。By the way, in such a muffling device, the optimum shape of the muffling speaker 4 is determined depending on the frequency of the sound to be muffled. In other words, in general, the radiation efficiency of speakers deteriorates in the low frequency range, so in order to prevent this it is necessary to use speakers with as large a diameter as possible, but in reality, due to the installation space, such It was not possible to use large speakers.
また、従来の消音装置では、ダクト２内を伝播してくる
音６がダクト２の中心軸方向に進む平面波であるのに対
し、スピーカ４からの２次音７はダクト２の中心軸とは
垂直な方向に向けて放射されるため、ダクト２の出口寸
前に消音用スピーカ４を配置すると、消音用スピーカ４
によるダクト軸方向の平面波を出口寸前で得ることがで
きず、第６図の８で示す如く音場の分布にむらを生じて
しまい、充分な消音効果が得られないという問題があっ
た。Furthermore, in the conventional silencer, the sound 6 propagating inside the duct 2 is a plane wave that travels in the direction of the central axis of the duct 2, whereas the secondary sound 7 from the speaker 4 is not directed toward the central axis of the duct 2. Since the sound is emitted in the vertical direction, if the sound deadening speaker 4 is placed just before the exit of the duct 2, the sound deadening speaker 4
Therefore, a plane wave in the axial direction of the duct cannot be obtained just before the exit, resulting in uneven distribution of the sound field as shown by 8 in FIG. 6, and there is a problem in that a sufficient silencing effect cannot be obtained.
（発明が解決しようとする課題）
このように、従来の能動制御型の消音装置では、ダクト
出口付近で音場の分布にむらを生じ、充分な消音効果が
得られないという問題があった。(Problems to be Solved by the Invention) As described above, the conventional active control type muffling device has a problem in that the distribution of the sound field becomes uneven near the duct exit, and a sufficient muffling effect cannot be obtained.
また、従来の装置では、低周波領域において、消音用ス
ピーカの充分な放射効率を得るためにはスピーカの設置
空間が大型化してしまうという問題があった。Further, in the conventional device, in order to obtain sufficient radiation efficiency of the silencer speaker in a low frequency region, there is a problem in that the installation space for the speaker becomes large.
本発明はかかる問題点に鑑みなされたもので、ダクト出
口寸前に消音用スピーカを設置した場合でも、ダクト出
口付近の音場の分布にむらを生じることがなく、シかも
装置全体の大型化を招くことなしに低周波領域における
スピーカの放射効率を高めることができる消音装置を提
゛供することを目的とする。The present invention was made in view of the above problem, and even when a silencing speaker is installed just before the duct exit, there is no unevenness in the distribution of the sound field near the duct exit, and it is possible to increase the size of the entire device. It is an object of the present invention to provide a silencing device that can increase the radiation efficiency of a speaker in a low frequency region without causing noise.
［発明の構成コ
（課題を解決するための手段）
本発明に係る消音装置は、音源からの音を伝播させる管
状のダクトと、このダクト内において前記音源から伝播
してきた音を採取するマイクロホンと、このマイクロホ
ンの出力信号を位相反転させる信号変換器と、前記ダク
トの出口に設けられ前記信号変換器からの出力信号によ
り駆動されて前記音源から伝播してきた音を消滅させる
２次音を発生させる消音用スピーカとを具備した消音装
置において、前記消音用スピーカは、前記ダクトの中心
軸を取り囲む環状スピーカであることを特徴とする。[Configuration of the Invention (Means for Solving the Problems) A silencer according to the present invention includes a tubular duct for propagating sound from a sound source, and a microphone for collecting the sound propagated from the sound source within the duct. , a signal converter that inverts the phase of the output signal of the microphone; and a signal converter that is provided at the outlet of the duct and is driven by the output signal from the signal converter to generate a secondary sound that eliminates the sound propagated from the sound source. In the noise reduction device including a noise reduction speaker, the noise reduction speaker is an annular speaker surrounding a central axis of the duct.
（作用）
本発明によれば、消音用スピーカがダクトの中心軸を取
り囲むような環状のスピーカによって構成されているの
で、ダクトの周囲全体からむらのない−様な音場を形成
することができる。(Function) According to the present invention, since the silencing speaker is constituted by an annular speaker that surrounds the central axis of the duct, it is possible to form an even sound field from the entire periphery of the duct. .
また、ホイヘンスの原理から明らかなように、点音源か
ら伝播した波面はさらにその波面に別の複数個の点音源
を配したときに生ずる波面の重ね合わせとなる。本発明
では、ダクトの中心軸を取囲むように設置された環状の
スピーカを点音源の集まりと考えることができるので、
ダクトの中心軸上の点音源とみなせる位置から発せられ
た音がダクト内を伝播したときに生ずる波面と、上記環
状のスピーカの各点音源からの音を重ね合わせたときの
波面とが一致するように設定することができる。従って
、ダクトの中心軸を取囲むように２次音となる消音用ス
ピーカを配置することによって、ダクト中心軸から外周
にかけて２次元的に広がるような音源に対しても充分な
消音効果を得ることができる。Furthermore, as is clear from Huygens' principle, the wavefront propagated from a point sound source becomes a superposition of wavefronts that occur when a plurality of other point sound sources are placed on top of that wavefront. In the present invention, the annular speakers installed so as to surround the central axis of the duct can be considered as a collection of point sound sources.
The wavefront generated when sound emitted from a position on the central axis of the duct that can be considered as a point sound source propagates inside the duct matches the wavefront when the sounds from each point sound source of the annular speaker are superimposed. It can be set as follows. Therefore, by arranging noise-muffling speakers that produce secondary sound so as to surround the center axis of the duct, a sufficient sound-muffling effect can be obtained even for sound sources that spread two-dimensionally from the center axis of the duct to the outer periphery. I can do it.
更に、消音用の環状スピーカとして圧電スピーカを使用
した場合、圧電スピーカは面全体が振動するため、小型
であっても低周波領域まで高い放射効率を得ることがで
きる。また、ダクトがバッフルの役目もするために低周
波領域までの高い放射効率を保証する効果もある。Furthermore, when a piezoelectric speaker is used as an annular speaker for noise reduction, the entire surface of the piezoelectric speaker vibrates, so even if the piezoelectric speaker is small, high radiation efficiency can be obtained even in the low frequency range. Furthermore, since the duct also serves as a baffle, it has the effect of ensuring high radiation efficiency up to the low frequency range.
（実施例）
以下、添付の図面に基づいて本発明の実施例について説
明する。(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.
第１図は本発明の一実施例に係る消音装置の構成を示す
図である。なお、第１図において、第６図に示した従来
の消音装置と同一部分には同一符号を付し重複する部分
の詳しい説明は省略する。FIG. 1 is a diagram showing the configuration of a silencer according to an embodiment of the present invention. In FIG. 1, the same parts as those of the conventional muffling device shown in FIG. 6 are given the same reference numerals, and detailed explanation of the overlapping parts will be omitted.
この装置が従来の装置と異なる点は、ダクト２の出口付
近に設けられた消音用スピーカ１１が、ダクト２の外周
を取囲む可撓性で環状の圧電スピ−カから構成されてい
る点にある。This device differs from conventional devices in that the silencing speaker 11 provided near the exit of the duct 2 is composed of a flexible annular piezoelectric speaker surrounding the outer periphery of the duct 2. be.
以下、この消音装置の動作について説明する。The operation of this silencer will be explained below.
音源１から発生された音はダクト２内を伝播し、集音マ
イク３により採取される。集音マイク３の出力信号は信
号変換回路６に入力される。信号変換回路５は、評価点
（ダクト出口）での音圧が０になるように計算された係
数と集音マイク３からの信号とを掛は合わせる。この係
数は音波の伝播時間やダクト２の伝達特性を考慮して設
定される。Sound generated from a sound source 1 propagates through a duct 2 and is collected by a sound collecting microphone 3. The output signal of the sound collecting microphone 3 is input to a signal conversion circuit 6. The signal conversion circuit 5 multiplies the signal from the sound collection microphone 3 by a coefficient calculated so that the sound pressure at the evaluation point (duct exit) becomes 0. This coefficient is set in consideration of the propagation time of sound waves and the transmission characteristics of the duct 2.
信号変換回路５の出力信号は消音用スピーカ１工へ与え
られる。これにより、消音用スピーカ１１からは２次音
が発生される。The output signal of the signal conversion circuit 5 is given to a silencer speaker 1. As a result, secondary sound is generated from the muffling speaker 11.
この装置では、消音用スピーカ１１が円環状に形成され
、ダクト２の出口付近に外装されているので、消音のた
めの２次音が円環状に−様に分布しているのと等価にな
る。このため、第２図に示すように、このスピーカ１１
が設置されているダクト面内に−様な音場１２を形成す
ることができる。従って、スピーカが一箇所だけに設置
された従来の消音装置に生じていた音場のむらを防ぐこ
とができる。In this device, the silencing speaker 11 is formed in an annular shape and is externally mounted near the exit of the duct 2, so that the secondary sound for silencing is equivalent to being distributed in a circular shape. . Therefore, as shown in FIG.
It is possible to form a --like sound field 12 within the duct surface where the duct is installed. Therefore, it is possible to prevent the unevenness of the sound field that occurs in conventional silencers in which the speaker is installed only in one place.
また、この消音装置では、第３図に示すように、ホイヘ
ンスの原理により、環状の消音用スピーカ１１の各点音
源Ｐ１１Ｐ２１・・・、Ｐ、、からの音を重ね合わせた
ときの波面とダクト２の中心軸上の音源Ｐからの波面Ｐ
。とを一致させることができる。このように、中心軸上
の音源Ｐを囲むように２次音の発生源を設置することに
より、更に消音効果を高めることができる。In addition, in this muffling device, as shown in FIG. 3, according to Huygens' principle, the wavefront and duct when the sounds from each point sound source P11P21..., P, of the annular muffling speaker 11 are superimposed. Wavefront P from sound source P on the central axis of 2
. can be matched. In this way, by installing the secondary sound generation sources so as to surround the sound source P on the central axis, the silencing effect can be further enhanced.
また、この実施例では、消音用スピーカ１１として圧電
スピーカを使用しているので、面全体を振動させること
ができ、スピーカの設置空間を大型化することなしに、
低周波領域まで放射効率を高めることができる。しかも
、この実施例では、環状の消音用スピーカ１１をダクト
２の外周に装着しているので、ダクト２がバッフルの役
目を果たし、特に低周波領域の放射効率を一層向上させ
ることができる。Furthermore, in this embodiment, since a piezoelectric speaker is used as the noise-reducing speaker 11, the entire surface can be vibrated, without enlarging the installation space for the speaker.
Radiation efficiency can be increased up to the low frequency range. Furthermore, in this embodiment, since the annular noise-reducing speaker 11 is attached to the outer periphery of the duct 2, the duct 2 serves as a baffle, and the radiation efficiency, especially in the low frequency range, can be further improved.
なお、このように消音用スピーカ１１をダクト２の外周
に装着する場合、ダクト２の肉厚に応じ、第４図に示す
ように、消音用スピーカ１１の外周に例えば剛体の金属
環のように圧電スピーカとは異なる材質の環状体２１を
装着すると、更に放射効率を高めることができる。In addition, when installing the muffling speaker 11 on the outer periphery of the duct 2 in this way, depending on the wall thickness of the duct 2, as shown in FIG. If the annular body 21 is made of a material different from that of the piezoelectric speaker, the radiation efficiency can be further increased.
また本発明は消音用スピーカをダクトの外周に装着した
ものに限定されるものではなく、例えば、第５図に示す
ように、ダクト２の内周に消音用スピーカ２２を装着し
た場合にも同様の効果を得ることができる。Furthermore, the present invention is not limited to a case in which a silencing speaker is mounted on the outer periphery of a duct; for example, as shown in FIG. effect can be obtained.
更に通常のスピーカを複数個円環状に配置しても良く、
この場合は、全てのスピーカから発せられる２次音が全
て同位相となるように制御すれば（制御は周知の方法に
より可能である）、同様の効果を得ることができる。Furthermore, a plurality of ordinary speakers may be arranged in a ring,
In this case, the same effect can be obtained by controlling so that all the secondary sounds emitted from all the speakers are in the same phase (control can be performed by a known method).
［発明の効果］
以上述べたように、本発明によれば、ダクトの出口付近
に環状の消音用スピーカを設けたので、ダクト出口付近
での音場を均一化することができ、またスピーカの設置
空間を小さくしたままスピーカの放射効率を向上させる
ことができる。更には、音源を囲むように２次音発生源
を設置しているので、ダクト中心軸から放射状に広がる
音に対する消音効果も得られる。[Effects of the Invention] As described above, according to the present invention, since the annular noise-reducing speaker is provided near the duct exit, the sound field near the duct exit can be made uniform, and the speaker The radiation efficiency of the speaker can be improved while reducing the installation space. Furthermore, since the secondary sound generation source is installed so as to surround the sound source, a silencing effect can be obtained for the sound that spreads radially from the central axis of the duct.
このため、本発明によれば、消音効果に優れた消音装置
を提供することができる。Therefore, according to the present invention, it is possible to provide a muffling device with excellent muffling effects.
第１図は本発明の一実施例に係る消音装置を示す図、第
２図は同装置における音場の分布を示す縦断面図、第３
図は同装置における各音源からの波面を説明するための
図、第４図及び第５図は本発明の他の実施例に係る消音
装置を夫々示す縦断面図、第６図は従来の消音装置を示
す縦断面図である。
１・・・音源、２・・・ダクト、３・・・集音マイク、
４゜１１．２２・・・消音用スピーカ、５・・・信号変
換回路、２１・・・環状体。
出願人代理人 弁理士 鈴江武彦
第
図
第
図
粥
図FIG. 1 is a diagram showing a silencing device according to an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view showing the distribution of a sound field in the same device, and FIG.
The figure is a diagram for explaining wavefronts from each sound source in the same device, FIGS. 4 and 5 are longitudinal cross-sectional views showing respective silencing devices according to other embodiments of the present invention, and FIG. 6 is a conventional silencing device. FIG. 2 is a longitudinal cross-sectional view showing the device. 1...Sound source, 2...Duct, 3...Sound collection microphone,
4゜11.22...Muffling speaker, 5...Signal conversion circuit, 21...Annular body. Applicant's agent Patent attorney Takehiko Suzue
Claims (1)
内において前記音源から伝播してきた音を採取するマイ
クロホンと、このマイクロホンの出力信号を位相反転さ
せる信号変換器と、前記ダクトの出口に設けられ前記信
号変換器からの出力信号により駆動されて前記音源から
伝播してきた音を消滅させる２次音を発生させる消音用
スピーカとを具備した消音装置において、前記消音用ス
ピーカは、前記ダクトの中心軸を取り囲む環状スピーカ
であることを特徴とする消音装置。A tubular duct for propagating sound from a sound source, a microphone for collecting sound propagated from the sound source within the duct, a signal converter for inverting the phase of the output signal of the microphone, and a signal converter provided at the exit of the duct. In the noise reduction device, the noise reduction device includes a noise reduction speaker that is driven by an output signal from the signal converter and generates a secondary sound that extinguishes the sound propagated from the sound source, wherein the noise reduction speaker is located along the central axis of the duct. A silencer characterized by being an annular speaker surrounding a silencing device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1083703A JPH02261997A (en) | 1989-03-31 | 1989-03-31 | Silencing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1083703A JPH02261997A (en) | 1989-03-31 | 1989-03-31 | Silencing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02261997A true JPH02261997A (en) | 1990-10-24 |
Family
ID=13809854
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1083703A Pending JPH02261997A (en) | 1989-03-31 | 1989-03-31 | Silencing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02261997A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10316946A1 (en) * | 2003-04-12 | 2004-10-21 | Daimlerchrysler Ag | Device and method for damping pressure oscillations in hydraulic lines |
| EP1796077A2 (en) * | 2005-12-07 | 2007-06-13 | Delphi Technologies, Inc. | Excitation of air directing valves and air handling surfaces in the cancellation of air handling system noise |
| JP2012088734A (en) * | 2011-12-26 | 2012-05-10 | Takenaka Komuten Co Ltd | Noise reduction device |
-
1989
- 1989-03-31 JP JP1083703A patent/JPH02261997A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10316946A1 (en) * | 2003-04-12 | 2004-10-21 | Daimlerchrysler Ag | Device and method for damping pressure oscillations in hydraulic lines |
| EP1796077A2 (en) * | 2005-12-07 | 2007-06-13 | Delphi Technologies, Inc. | Excitation of air directing valves and air handling surfaces in the cancellation of air handling system noise |
| EP1796077A3 (en) * | 2005-12-07 | 2011-06-29 | Delphi Technologies, Inc. | Excitation of air directing valves and air handling surfaces in the cancellation of air handling system noise |
| JP2012088734A (en) * | 2011-12-26 | 2012-05-10 | Takenaka Komuten Co Ltd | Noise reduction device |
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