JP2017058491A - Active noise suppression device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a noise suppression action for a long period of time by suppressing a rise of temperatures of main sound collection means and sound production means, in an active noise suppression device which suppresses the propagation of noise in a flow passage.SOLUTION: In an air channel body 1 constituting a cylindrical air channel, sound collecting means 2a, 2b for detecting noise which propagates the inside of the air channel body 1, and sound production means 3 for radiating a suppression sound to the inside of the air channel body 1 are firmly arranged at an external wall face of an air channel wall 5 as a constitution which is divided to the inside and outside by the air channel wall 5, and the sound collection means 2a, 2b and the sound production means 3 become possible to detect the noise which propagates the inside of the air channel body 1 via the air channel wall 5, and to radiate the suppression sound, a rise of a temperature can be thereby suppressed by avoiding direct exposure to a high-temperature state, and an active noise suppression device which can maintain a noise suppression action for a long period of time can be obtained.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an active noise suppression device that actively suppresses propagation of noise in an air passage.

  At present, air conditioners mainly having an air blowing function are widely used, and technical developments for improving problems such as improving the capability of the main functions and reducing the power consumption are being made every day.

  There exists suppression of the noise which generate | occur | produces in such a subject.

  In particular, in an air passage intended to convey a flowing air that is a flow of blown air, it is a problem to suppress noise propagating inside. In particular, from the viewpoint of increasing wind resistance, it is a big problem in that it is difficult to cope with simple physical soundproofing alone.

  Here, the air path for the purpose of conveying the flowing air is, for example, an air-conditioning duct that draws air from the outside to the inside by blowing by a blower, or a range for exhausting cooking smoke to the outside based on the blowing. Indicates the ventilation path of the hood. And especially the noise which propagates from a fan to the indoor side is a subject.

  There is ANC as one of the techniques for effectively suppressing noise propagating in the air passage without greatly increasing the flow resistance.

  This ANC indicates active noise control, and is an active noise suppression technique that suppresses noise by sound interference by generating a sound having an opposite phase to the noise to be suppressed.

  In such ANC technology, a microphone as a sound collecting means for detecting sound and a speaker as a sound generating means for generating sound are basic components and essential devices.

  However, when the application target of this ANC is a range hood or the like in which the temperature inside the air passage may become very high, exposure of the microphone or speaker to a high temperature state becomes a problem.

  In other words, since microphones and speakers are generally assumed to be used at room temperature around 25 ° C., initial performance is lost due to physical deterioration when exposed to high temperature conditions exceeding specifications for a long period of time. Thereby, the point that the long-term maintenance of a noise suppression function becomes difficult was a problem.

  Conventionally, this type of active noise suppression device is known to solve such a problem, in which a mounted microphone or speaker is not easily exposed to a high temperature state (see, for example, Patent Document 1). .

  Hereinafter, a conventional active noise suppression device will be described with reference to FIG.

  As shown in the figure, the conventional active noise suppression device includes a discharge port 100 communicating with the outdoors, a suction port 101 for sucking exhaust air, and a ventilation path 102 for carrying a flowing air connecting the discharge port 100 and the suction port 101. A ventilation fan 103 for generating a flowing air in the ventilation path 102 is provided.

  In addition, the conventional active noise suppression device includes a noise detection microphone 104 that detects noise, a speaker 105 that emits a suppression sound that has an opposite phase to the noise detected by the noise detection microphone 104, and noise suppression. An active silencer 107 including an error detection microphone 106 for detecting a state is provided.

  Further, the conventional active noise suppression device connects the outer wall surface of the device and the ventilation path 102, and is provided with a bypass path 108 that allows external air to flow in, and faces the bypass path 108 in the vicinity of the ventilation path 102 to connect the speaker 105. It is arranged.

  Furthermore, the noise detection microphone 104 is disposed facing the bypass path 108 other than the bypass path where the speaker 105 is disposed. Further, the error detection microphone 106 is disposed on the suction port 101 side.

  With the above configuration, the noise detection microphone 104, the speaker 105, and the error detection microphone 106 can be arranged in a space where noise equivalent to that in the ventilation path 102 is propagated, so that it is possible to obtain a noise suppression effect. It is going to be.

  Further, since the air in the ventilation path 102 is sucked by the ventilation fan 103, the pressure in the ventilation path 102 is lower than that in the bypass path 108. As a result, high-temperature air in the ventilation path 102 flows backward and does not enter the bypass path 108, and external low-temperature air is attracted by the main flow in the ventilation path 102 and flows through the bypass path 108. This prevents the noise detection microphone 104, the speaker 105, and the error detection microphone 106 from being exposed to a high temperature state.

JP 2014-6014 A

  In such a conventional active noise suppression device, a bypass path 108 for allowing outside air to flow into the ventilation path 102 is provided, and the noise detection microphone 104, the speaker 105, and the error detection microphone face the inside of the ventilation path 102. 106.

  With such a configuration, external low-temperature air is attracted into the ventilation path 102 via the bypass path 108.

  Therefore, the noise detection microphone 104, the speaker 105, and the error detection microphone 106 are prevented from being exposed to a high temperature state.

  However, since the noise detection microphone 104, the speaker 105, and the error detection microphone 106 are disposed in the bypass path 108, the noise detection microphone 104, the speaker 105, and the error detection microphone 106 are directly affected by surrounding sounds other than the ventilation path 102, and the suppression sound leaks to the outside. It becomes.

  As a result, the surrounding sound becomes an error factor, and the expected noise suppression capability cannot be obtained.

  In addition, the suppression sound leaked to the surroundings becomes a source of noise increase and interferes with the noise suppression action, which makes it difficult to perform a normal noise suppression function.

  Therefore, the present invention solves the above-described conventional problems, and active noise that can maintain the noise suppression action for a longer period of time without affecting the noise suppression capability even when the airflow inside the air passage body is high temperature. An object is to provide a suppression device.

  In order to achieve this object, a noise suppression device according to the present invention includes a cylindrical air passage body through which blown air passes, an air passage wall constituting a side surface of the air passage body, and the air passage wall. Sound collecting means for detecting noise propagating inside the air passage body on the outer wall surface as vibration of the air passage wall and outputting an electric signal corresponding to the noise, and a noise electric signal output from the sound collecting means The control means for generating the suppression electric signal for suppressing the noise corresponding to the noise electric signal based on the noise, and generated by the control means by vibrating the air passage wall on the outer wall surface of the air passage wall And a sounding means for radiating a suppression sound corresponding to the suppressed electrical signal to the inside of the air passage body, thereby achieving the intended purpose.

  According to the present invention, since the temperature rise of the sound collecting means and the sound generating means can be suppressed without affecting the noise suppression capability, it is possible to obtain an effect that the noise suppression action can be maintained for a longer period.

The front view which cut and showed the structure of the active noise suppression apparatus which concerns on Embodiment 1 of this invention partially The side view which showed the structure of the active noise suppression apparatus which concerns on Embodiment 1 of this invention The front view which showed the structure of the attachment of an air channel wall and sounding means with which the active noise suppression apparatus which concerns on Embodiment 1 of this invention was equipped with the notch cross section in the center part of sounding means The front view which showed the other structure of the attachment of the wind path wall with which the active noise suppression apparatus which concerns on Embodiment 1 of this invention, and a sounding means were notched in the center part of the sounding means Side view showing the configuration of a conventional device in a cutaway section in the lateral direction

  An active noise suppression device according to the present invention includes a cylindrical air passage body through which blown air passes, an air passage wall constituting a side surface of the air passage body, and an outer wall surface of the air passage wall. Sound collecting means for detecting noise propagating inside as vibration of the air passage wall and outputting an electric signal corresponding to the noise, and corresponding to the noise electric signal based on the noise electric signal output from the sound collecting means Control means for generating a suppression electrical signal for suppressing noise and suppression corresponding to the suppression electrical signal generated by the control means by vibrating the air passage wall on the outer wall surface of the air passage wall And a sound generation means for emitting sound to the inside of the air passage body.

  As a result, the sound collecting means and the sound generating means are configured to detect noise propagating through the air passage body through the air passage wall in a state where the sound collecting means and the sound generation means are arranged and fixed on the outer wall surface of the air passage wall that is outside the air passage body. And suppression sound can be emitted.

  Therefore, even when the air flow inside the air passage body is high temperature, the sound collecting means and the sound generation means are outside the air passage body, and it is possible to avoid direct exposure to a high temperature state, which affects the noise suppression capability. Since the temperature rise of the sound collecting means and the sound generating means can be suppressed without any effect, the noise suppressing effect can be maintained for a longer period.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention.

  In addition, throughout the drawings, the same portions are denoted by the same reference numerals, and the second and subsequent descriptions are omitted. Furthermore, in each drawing, the description of the details of each part not directly related to the present invention is omitted.

(Embodiment 1)
As shown in FIGS. 1 and 2, the active noise suppression device according to the present embodiment includes an air passage body 1, sound collection means 2 a and 2 b, sound generation means 3, and a control device 4.

  The air passage body 1 has a cylindrical shape and constitutes an air passage for allowing a flow of blown air to pass therethrough. The air passage body 1 is constituted by an air passage wall 5, and the inside and the outside are divided by the air passage wall 5.

  The sound collecting means 2a and 2b detect noise propagating through the inside of the air passage body 1 from the sound source as vibration of the air passage wall 5, and output a noise electric signal corresponding to the noise. Here, detection as vibration of the air passage wall 5 means that the sound collecting portions of the sound collecting means 2a and 2b and the inside of the air passage are spatially independent, and air passing through the space is collected by the sound collecting means 2a and 2b. Means no direct contact.

  The control device 4 generates a suppression electric signal for suppressing noise corresponding to the noise electric signal output from at least one of the sound collecting means 2a and 2b.

  The sound generation unit 3 radiates a suppression sound corresponding to the suppression electrical signal generated by the control device 4 to the inside of the air passage body 1.

  Each of the sound collecting means 2a, 2b and the sound generating means 3 is disposed on and closely attached to the outer wall surface of the air passage wall 5 serving as the inner and outer boundary wall surfaces of the air passage body 1.

Each of the sound collecting means 2a and 2b and the sound generating means 3 is covered with a separation box 6.
The separation box 6 is also fixed to the outer wall surface of the air passage wall 5 so that the sound of the sound collecting means 2a and 2b due to the ambient sound of the air passage body 1 is detected and the sound from the sound generating means 3 is directly detected. The sound leakage to the surroundings is prevented.

  Here, the air passage body 1 is an air passage for allowing the air flow of the blown air to pass through. For example, from the intake duct to the exhaust duct of the piping duct, the range hood, and the air purifier in the ventilation blow for guiding the blown air. This is the air flow path.

  Although not shown in the drawing, the blown air flowing inside the air passage body 1 is generated by an electric blower based on the rotational drive of blades by an electric motor, and this electric blower generates sound. As a result, noise that propagates through the inside of the air passage body 1 is generated.

  Therefore, for example, if the electric blower is disposed on the left side of the air passage body 1 in the horizontal direction in FIG. 2, the noise propagates through the inside of the air passage body 1 from the left to the right.

  Here, each sound collecting means 2a, 2b is not particularly defined as long as it detects the vibration of the object and outputs an electric signal.

  For example, a dynamic microphone that uses a voltage generated in a conductor coil that moves in a magnetic field due to vibration, or a vibration detection configuration that mainly receives a vibration from a piezoelectric element and uses the voltage generated when the piezoelectric element is deformed, In addition, a vibration detection device called a concrete microphone or a vibration pickup can be used.

  The sound generation means 3 is not particularly defined as long as it emits sound indirectly into the space through the object vibrated by vibrating the object in accordance with the applied electric signal.

  For example, an excitation device having the same basic configuration as that of a dynamic speaker that uses vibration generated in a conductor coil when a sound voltage signal is applied to a commonly used conductor coil in a magnetic field may be used.

  Further, since the control device 4 for generating an electric signal is not different from that required in the conventional active noise suppression device, the detailed description is omitted as described above.

  In this description, a configuration including two independent individual sound collecting means 2a and 2b in the drawing is shown.

  In this case, for example, if a noise source is present upstream of the wind path body 1 on the sound collecting means 2a side, the sound collecting means 2a serves as a reference sensor for detecting the state of noise to be suppressed.

  Further, the sound collecting means 2b on the downstream side of the propagation of noise is for detecting the noise suppression effect due to the sound emission from the sound generating means 3 (basically the sound that is the antiphase of the sound signal detected by the reference sensor). It becomes an error sensor.

  Therefore, the illustrated configuration is a feedforward type ANC device configuration that is generally used as an active noise suppression device.

  Although not shown in the figure, the active noise suppression device may be configured to use only an error sensor that does not use a reference sensor. In this case, the device configuration is a feedback type ANC.

  Thus, in the conventional active noise suppression apparatus, many configurations using one to a plurality of sound collecting means have been devised, but since they do not depend on the gist of the present plan, details of each configuration using the drawings are explained. Will be omitted.

  In addition, a configuration using a plurality of sound generating means 3 that emits the suppression sound has been devised, but a detailed description thereof is omitted as described above.

  The separation box 6 is not particularly limited as long as it can suppress the conduction of sound from the external space of the separation box 6 to the internal space of the separation box 6. What is necessary is just to comprise by the resin and metal material which match the use requirements (strength, temperature-proof performance, etc.) requested | required in actual use.

  Next, details of the mounting structure of the sounding means 3 to the outer wall surface of the air passage wall 5 of the air passage body 1 will be described with reference to FIG.

  Note that the configuration of attaching the sound collecting means 2a, 2b to the air passage wall 5 is not greatly changed in accordance with that of the sound generating means 3, and therefore detailed description thereof is omitted.

  FIG. 3 shows an AA cross section by cutting the sound path 3 including the sound generation means 3 at the center of the sound generation means 3 when the air passage body 1 is viewed from the front direction shown in FIG.

  The sound generation means 3 vibrates the object as described above, and includes the frame portion 3a that forms the outline and the vibration portion 3b that vibrates with the frame portion 3a as a reference in accordance with the applied electrical signal.

  A configuration in which the frame portion 3 a and the excitation portion 3 b of the sound generating means 3 are fixedly attached to the outer wall surface of the air passage wall 5 is a basic configuration for attaching the sound generating means 3 to the air passage body 1.

  In addition, depending on the configuration of the sound generation means 3, there is also one that can be attached to the air passage body 1 only by fixing the vibration portion 3b to the air passage wall 5.

  At this time, a zone where the vibration portion 3b of the air passage wall 5 is in close contact with each other becomes a vibration plate 5a (a portion indicated by a dashed line in the drawing) that is vibrated by the vibration portion 3b. The suppression sound can be emitted to the inside of the road body 1.

  It should be noted that it is desirable to apply flexibility enhancing means 5b around the portion of the air passage wall 5 that becomes the diaphragm 5a in order to improve the followability of the diaphragm 5a portion with respect to the vibration of the vibration exciting portion 3b.

  For example, as shown in the figure, the flexible reinforcing means 5b is thinned as compared with the air passage wall 5 that is annular when viewed from the front direction around the air passage wall 5 that becomes the diaphragm 5a. A thin portion is provided, and this thin portion improves the followability of the diaphragm 5a to the vibration of the vibrating portion 3b. Further, the diaphragm 5a constituting the inner circumference of the flexible reinforcing means 5b that is annular is also made thinner than the air passage wall 5, in other words, the air passage wall 5 is made thinner than the surroundings. Yes. This weight reduction enhances the follow-up performance of the excitation unit 3b. Further, the frame portion 3a of the sound generating means 3 is fixed to the outer peripheral side region 7 of the flexible reinforcing means 5b which is the outer wall surface of the air passage wall 5 and is annular. Since the vibration of the vibration part 3b vibrates with the frame part 3a as a reference, the vibration energy of the vibration part 3b is efficiently applied only to the diaphragm 5a by fixing the frame part 3a to the outer peripheral side region 7. Can be given.

  The point of improving the followability of the diaphragm 5a with respect to the vibration of the excitation unit 3b is to make adjustments with a focus on effectively transmitting vibrations in the frequency band of noise to be suppressed in practical use. .

  As described above, if the flexibility enhancing means 5b is further thinned to increase the flexibility, it is possible to improve the permeability in the low frequency band.

  In addition, the structure of the flexible reinforcement | strengthening means 5b is not restricted to thickness reduction, You may use another structure.

  For example, as shown in FIG. 4, by applying a cather structure that increases the area of the movable part by providing a plurality of pleats, the movable width with respect to the vibration direction can be expanded, and the followability can be further improved.

  In addition, it is not an essential requirement to provide the flexible reinforcement means 5b, and it is not necessary to provide a noise suppressing function even if the structural material of the air passage wall 5 is used.

  Here, the fixing of the frame portion 3a and the vibrating portion 3b of the sound generating means 3 to the outer wall surface of the air passage wall 5 is not particularly limited as long as the fixing can be maintained for a long time without causing a tear due to the vibration of the vibrating portion 3b. There is no regulation, and for example, an adhesive such as screwing or epoxy resin may be used.

  According to such a configuration, the air passage body 1 constituting the cylindrical air passage is configured such that the inside and outside are separated by the air passage wall 5, and the air passage body 1 is formed on the outer wall surface of the air passage wall 5. Sound collecting means 2a, 2b for detecting internal noise and sound generating means 3 for radiating a suppression sound are arranged in close contact with the inside of the air passage body 1 and fixedly attached.

  In addition, by providing the flexible reinforcing means 5b at the part where the sound collecting means 2a and 2b and the sound generating means 3 are attached to the air passage wall 5, it is possible to further improve the permeability of vibrations that are the frequency band of the noise to be suppressed. it can.

  As a result, the sound collecting means 2a, 2b and the sound producing means 3 are in a state of being fixedly attached to the outer wall surface of the air passage wall 5 which is the outside of the air passage body 1, and the air passage through the air passage wall 5. Detection of noise propagating inside the body 1 and emission of suppression sound are possible.

  Therefore, even when the airflow inside the air passage body 1 is high temperature, the sound collection means 2a, 2b and the sound generation means 3 are outside the air passage body 1, and it is possible to avoid direct exposure to a high temperature state. Thus, since the temperature rise can be suppressed, it is possible to obtain an effect that the noise suppressing action can be maintained for a longer period.

  The active noise suppression device according to the present invention effectively suppresses the temperature rise of the sound collection means and the sound generation means even when the flow of air in the air passage for conveying the blown air is high, and has a noise propagation suppression function. Since it can be maintained for a long period of time, it is useful as an active noise suppression device or the like used for a ventilation device such as a general household range hood.

DESCRIPTION OF SYMBOLS 1 Air path body 2a, 2b Sound collection means 3 Sound generation means 3b Excitation part 4 Control apparatus 5 Air path wall 5b Flexible reinforcement means

Claims (5)

A cylindrical air passage body through which blown air passes;
An air passage wall constituting a side surface of the air passage body;
Sound collecting means for detecting noise propagating inside the air passage body at the outer wall surface of the air passage wall as vibration of the air passage wall and outputting an electric signal corresponding to the noise;
Based on the noise electric signal output from the sound collecting means, the air passage wall is formed by control means for generating a suppression electric signal for suppressing the noise corresponding to the noise electric signal and the outer wall surface of the air passage wall. Sound generation means for radiating suppression sound corresponding to the suppression electrical signal generated by the control means by oscillating to the inside of the air passage body,
An active noise suppression device. An outer wall surface of the air passage wall,
2. The active noise suppression device according to claim 1, wherein a flexible reinforcement means for increasing vibration permeability for suppressing noise to be suppressed is provided on a fixed portion of the sound collection means and / or the sound generation means. The flexibility enhancing means is:
The active noise suppression device according to claim 1, wherein the active noise suppression device is a thin portion that is thinner than the air passage wall. The flexibility enhancing means is:
The thin part is annular,
The inner circumference of the flexibility enhancing means is
The active noise suppression device according to claim 3, wherein the diaphragm is thinner than the air passage wall. The pronunciation means is:
A frame portion constituting the outline of the sound generation means;
An excitation unit that generates vibrations inside the frame unit;
The frame part is
The active noise suppression device according to any one of claims 2 to 4, wherein the active noise suppression device is fixed to an outer peripheral side region of the flexible reinforcement means.

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