JPH08278788A - Active muffling device for duct - Google Patents

Abstract

PURPOSE: To appropriately correct a control characteristic while avoiding derivative problems with respect to the change of an acoustic transfer characteristic due to the changing of the opening degree of a damper in an active muffling device for duct. CONSTITUTION: This device is constituted by providing a secondary sound generator 3 in an air blowing duct 1 in which a damper 2 is interpolatingly arranged and by providing a control means 6 making the secondary sound generator 3 generate a secondary sound made be interferenced in the state of an opposite phase and the same amplitude with respect to a muffling objective sound propagating in the ventilating duct 1. Moreover, the device is provided with an opening degree detecting means 11 detecting the opening degree θof the damper 2 and a correcting means 10 correcting set characteristics Bs, Cs of the characteristic part X in the control part 6 according to the detected opening degree θof the damper 2 of the opening degree detecting means 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is designed to cause a secondary sound of the same amplitude to have a phase opposite to that of a sound to be silenced (generally noise) propagating in a ventilation duct (so-called destructive interference). Regarding an active muffling device for ducts that obtains a muffling effect,
Specifically, a secondary sound generator is provided in the air duct with the damper interposed, and the secondary sound that interferes with the noise to be silenced propagating in the air duct in the opposite phase and in the same amplitude is generated by the secondary sound generator. The present invention relates to an active muffler for a duct, which is provided with control means for generating the noise.

[0002]

2. Description of the Related Art Conventionally, there have been the following active silencers for ducts of this type as described in (a) and (b) below. (A) As shown in FIG. 6, a reference sound receiver 4 is provided upstream of the secondary sound generator 3 in the blower duct 1, and an evaluation sound receiver is provided downstream of the secondary sound generator 3. A vessel 5 is provided.
Further, the control means 6 for causing the secondary sound generator 3 to generate a secondary sound.
Is the secondary sound creating means 7 for creating an output signal for secondary sound generation to the secondary sound generator 3 based on the sound receiving signal of the reference sound receiver 4, and the sound reception of the evaluation sound receiver 5. On the basis of the signal, the signal producing operation of the secondary sound producing means 7 is adjusted under the setting characteristic Cs, and the adaptive means 8 for increasing the sound deadening is provided. Then, a sensor S that detects the temperature and the air velocity in the air duct 1 is provided, and a correction unit 10 ′ that corrects the setting characteristic Cs of the adaptation unit 8 based on the detection signal of the sensor S is provided.

That is, the setting characteristic Cs in the adaptive means 8 is set in consideration of the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5, and the setting characteristic Cs is set. The purpose of compensating for the positional difference in the acoustic transmission between the secondary sound generator 3 and the evaluation sound receiver 5 by adjusting the signal creating operation of the secondary sound creating means 7 based on the sound receiving signal of the sound device 5. Although the acoustic transfer characteristics in the air duct 1 change due to changes in temperature and airflow velocity, the setting characteristic C of the adaptive means 8 is based on the detection result of temperature and airflow velocity as described above.
By correcting s, the setting characteristic C of the adaptive means 8 is corrected.
s is made to be a characteristic suited to the acoustic transmission characteristic at that time.

(B) As shown in FIG. 7, the control means 6 has the same structure as the above (a), but the blower duct 1
The following configuration is adopted as a means for correcting the setting characteristic Cs of the adapting means 8 with respect to the change in the acoustic transfer characteristic. That is, it is included in the monitor signal transmitting means 10m for providing the secondary sound generator 3 with a monitor signal having a frequency outside the frequency band of the secondary sound to be interfered with the sound to be muted, and the sound reception signal of the evaluation sound receiver 5. The time difference detection means 10n for detecting the arrival time difference of the corresponding monitor signals, and the correction means 10 "
Is the set characteristic Cs of the adaptive means 8 according to this detection time difference.
To correct the setting characteristic Cs of the adaptive means 8 according to the acoustic transfer characteristic at that time (for example, see Japanese Patent Laid-Open No. 6-159781).

[0005]

However, in the above-mentioned form (a), the sensor S arranged in the blower duct 1 for detecting the temperature and the airflow velocity causes a new noise due to generation of wind noise. There is a source problem. In addition, there is a problem that these sensors S are easily damaged by being exposed to the air flow in the blower duct 1, especially when cold air, warm air, or humidified air is a ventilation target.

On the other hand, in the above-mentioned form (b), by using a frequency outside the frequency band of the secondary sound for the monitor signal, the monitor sound itself generated from the secondary sound generator 3 is muted by this monitor signal. Although it is not set as the target sound, there is a problem that the monitor sound becomes new noise and the noise as a whole becomes large even if it is not the target sound. Also, as described above, the monitor signal transmitting means 1
Since the means 10n for detecting the arrival time difference of 0 m or the monitor signal is required, the structure of the control means 6 becomes complicated, which makes it difficult to manufacture and raises the cost of the apparatus.

In view of the above situation, the object of the present invention is to control characteristics while avoiding the derivative problems of the conventional apparatus against changes in the acoustic transfer characteristics due to changes in the opening of the damper interposed in the air duct. Is to be able to appropriately correct.

[0008]

[Means for Solving the Problems]

[First Characteristic Configuration] In the first characteristic configuration of the present invention (the characteristic configuration of the present invention according to claim 1), a secondary sound generator is provided in a blower duct having a damper interposed therebetween and propagates in the blower duct. An opening for detecting the opening of the damper in an active silencer for a duct, which is provided with control means for causing the secondary sound generator to generate a secondary sound that interferes with the sound to be silenced in an opposite phase and with the same amplitude The detection means and the correction means for correcting the set characteristic of the characteristic portion of the control means according to the detected damper opening degree of the opening degree detection means are provided.

[Second Characteristic Configuration] A second characteristic structure of the present invention (a characteristic structure of the present invention according to claim 1) is for specifying a specific structure suitable for carrying out the first characteristic structure. In the blower duct, a reference sound receiver is provided on the upstream side of the secondary sound generator, and an evaluation sound receiver is provided on the downstream side of the secondary sound generator, and the control means is Based on the sound reception signal of the reference sound receiver, based on the sound reception signal of the evaluation sound receiver, and a secondary sound creation means for creating an output signal for secondary sound generation for the secondary sound generator. ,
Adjusting means for adjusting the signal creating operation of the secondary sound creating means under a set characteristic to increase the volume of the sound deadening, and the correcting means sets the adaptive means as the characteristic portion to be corrected The setting characteristic of the means is corrected according to the detected damper opening.

[Third Characteristic Configuration] A third characteristic configuration of the present invention (characteristic configuration of the present invention according to claim 3) specifies a specific configuration suitable for carrying out the first or second characteristic configuration. In the blower duct, a reference sound receiver is provided on the upstream side of the secondary sound generator, and the control means generates the secondary sound based on a sound reception signal of the reference sound receiver. Sound producing means for producing an output signal for generating a secondary sound to the instrument, and the sound reception of the reference sound receiver input to the secondary sound producing means based on the output signal of the secondary sound producing means. Adjusting the signal under the set characteristic, and howling prevention means for preventing howling, and the correction means, the howling prevention means as the characteristic portion of the correction target,
The setting characteristic of the howling prevention means is corrected according to the detected damper opening degree.

[Fourth Characteristic Configuration] A fourth characteristic configuration of the present invention (a characteristic configuration of the present invention according to claim 4) specifies a specific configuration suitable for carrying out the first characteristic configuration. In the air duct, an evaluation sound receiver is provided on the downstream side of the secondary sound generator, and the control means is a secondary device for the secondary sound generator based on a sound reception signal of the evaluation sound receiver. A secondary sound producing means for producing an output signal for producing sound, and a signal producing operation of the secondary sound producing means is adjusted based on the received sound signal of the evaluation sound receiver under a set characteristic to reduce the volume. The adaptive means is configured to correct the set characteristic of the adaptive means in accordance with the detected damper opening degree by using the adaptive means as the characteristic portion to be corrected. .

[Fifth Characteristic Configuration] The fifth characteristic configuration of the present invention (the characteristic configuration of the present invention according to claim 5) specifies a specific configuration suitable for carrying out the first or fourth characteristic configuration. Yes, in the air duct, an evaluation sound receiver is provided on the downstream side of the secondary sound generator, and the control means is based on a sound reception signal of the evaluation sound receiver, and the secondary sound generator. To a secondary sound generation means for generating an output signal for generating a secondary sound, and the sound reception signal of the evaluation sound receiver input to the secondary sound generation means based on the output signal of the secondary sound generation means Adjusting under set characteristics, and howling prevention means for preventing howling, and the correction means, the howling prevention means as the characteristic portion of the correction target,
The setting characteristic of the howling prevention means is corrected according to the detected damper opening degree.

[Sixth Characteristic Configuration] A sixth characteristic configuration of the present invention (a characteristic configuration of the present invention according to claim 6) is for specifying a specific configuration suitable for carrying out the first characteristic configuration. In the air duct, a reference sound receiver is provided on the upstream side of the secondary sound generator, and the control means is a secondary device for the secondary sound generator based on a sound reception signal of the reference sound receiver. The secondary sound creating means for creating an output signal for sound generation under the set characteristic is provided, and the correcting means sets the secondary sound creating means as the characteristic part to be corrected. The characteristic is that it is corrected according to the detected damper opening.

[Seventh Characteristic Configuration] A seventh characteristic structure of the present invention (a characteristic structure of the present invention according to claim 7) is for specifying a specific structure suitable for carrying out the first characteristic structure. A drive state detection means for detecting a drive state of a drive device which is a source of a sound to be silenced is provided, and an evaluation sound receiver is provided downstream of the secondary sound generator in the blower duct, and the control means is provided. Is based on the detection signal of the drive state detection means, based on the sound reception signal of the secondary sound creation means for creating an output signal for secondary sound generation to the secondary sound generator, and the evaluation sound receiver. Adjusting means for adjusting the signal producing operation of the secondary sound producing means under a set characteristic so as to increase the volume of the sound deadening, the correcting means using the adaptive means as the characteristic portion to be corrected. The setting characteristic of the adaptive means is set to In that a configuration for correcting in accordance with the path opening.

[Eighth Characteristic Configuration] An eighth characteristic structure of the present invention (a characteristic structure of the present invention according to claim 8) is for specifying a specific structure suitable for carrying out the first characteristic structure. A drive state detection means for detecting the drive state of the drive device that is the source of the sound to be muted is provided, and the control means is
The secondary sound generating means for generating an output signal for generating a secondary sound to the secondary sound generator based on a detection signal of the driving state detecting means under a set characteristic is provided, and the correcting means is provided with the secondary sound. The creation means is the characteristic part to be corrected, and the setting characteristic of the secondary sound creation means is corrected according to the detected damper opening.

[0016]

[Action]

[Operation of First Characteristic Configuration] In the first characteristic configuration (see FIG. 1), when the opening degree θ of the damper 2 is changed for the purpose of adjusting the air flow rate, the ventilation duct 1 is changed by changing the damper opening degree θ.
In contrast to the change in the acoustic transfer characteristic in the inside, the setting characteristic of the characteristic portion X in the control means 6 (that is, the air duct 1
The characteristics set in consideration of the acoustic transmission characteristics in the inside) are corrected by the correction means 10 according to the damper opening degree θ detected by the opening degree detection means 11, so that the set characteristics of the characteristic portion X are changed from time to time. Therefore, the control operation of the control means 6 is appropriately maintained regardless of the change of the acoustic transfer characteristic due to the change of the damper opening θ, and the good silencing performance is maintained.

[Operation of Second Characteristic Configuration] In the second characteristic configuration (see FIG. 1), the reference sound receiver 4 receives the sound to be muted on the upstream side of the secondary sound generator 3. On the other hand, based on the sound receiving signal of the reference sound receiver 4, the secondary sound creating means 7 outputs the output signal for generating the secondary sound (that is, the muffling sound that has progressed downstream from the sound receiving point of the reference sound receiver 4). At a point of interference with the target sound, a signal is generated which causes the secondary sound generator 3 to generate a secondary sound having the same amplitude and a phase opposite to that of the target sound to be silenced.

Further, in contrast to the evaluation sound receiver 5 detecting the residual sound at the sound receiving point, the adapting means 8 produces the secondary sound based on the sound reception signal of the evaluation sound receiver 5. By adjusting the signal generating operation of the means 7 in a feedback control manner under the setting characteristic Cs, the sound deadening volume is increased (in other words, the remaining sound volume is decreased). The setting characteristic Cs of the adaptation means 8
Is a characteristic set in consideration of the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5, and a secondary sound is created based on the sound reception signal of the evaluation sound receiver 5. The purpose is to compensate the positional difference in the acoustic transmission between the secondary sound generator 3 and the evaluation sound receiver 5 in adjusting the signal generating operation of the means 7.

The acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 changes in accordance with the change of the damper opening θ. By correcting the setting characteristic Cs of the means 8 by the correcting means 10 according to the detected damper opening θ, the setting characteristic Cs of the adapting means 8 is corrected.
In accordance with the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 at that time, whereby the adjustment function of the adaptation means 8 with respect to the secondary sound creating means 7 is adjusted by the damper. Properly maintain regardless of the change in the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 due to the change in the opening degree θ,
The effect of increasing the volume is kept high.

[Operation of Third Characteristic Configuration] In the third characteristic configuration (see FIG. 1), the reference sound receiver 4 is provided upstream of the secondary sound generator 3 as in the second characteristic configuration. In response to receiving the sound to be silenced, the secondary sound creating means 7 creates an output signal for secondary sound generation based on the received sound signal of the reference sound receiver 4.

Based on the output signal of the secondary sound creating means 7, the howling preventing means 9 sets the sound receiving signal of the reference sound receiver 4 input to the secondary sound creating means 7 to the setting characteristic Bs.
By adjusting below, the howling due to the secondary sound being taken in by the reference sound receiver 4 is prevented. The setting characteristic Bs of the howling prevention means 9 is determined by the reference sound receiver 4
Is a characteristic set in consideration of the acoustic transfer characteristic B between the secondary sound generator 3 and the secondary sound generator 3, and is a sound received for reference from the sound reception signal of the reference sound receiver 4 given to the secondary sound creating means 7. In order to prevent the howling by removing the amount of the secondary sound taken in by the device 4, in terms of acoustic transmission between the secondary sound taking position by the reference sound receiver 4 and the secondary sound generating position by the secondary sound generator 3. The purpose is to compensate for the position difference.

The acoustic transmission characteristic B between the reference sound receiver 4 and the secondary sound generator 3 changes with the change of the damper opening θ, whereas the howling as the characteristic portion X changes. The setting characteristic Bs of the prevention means 9 is corrected by the correction means 10 according to the detected damper opening θ, so that the setting characteristic Bs of the howling prevention means 9 is changed from time to time to the reference sound receiver 4 and the secondary sound generator 3. According to the sound transmission characteristic B between the reference sound receiver, the adjustment function of the howling prevention means 9 with respect to the sound reception signal of the reference sound receiver 4 is adjusted by changing the damper opening θ. 4 and the secondary sound generator 3 are properly maintained regardless of the change in the acoustic transfer characteristic B, and the howling prevention effect and, in turn, the silencing performance are maintained high.

[Operation of Fourth Characteristic Configuration] In the fourth characteristic configuration (see FIG. 2), the evaluation sound receiver 5 receives the residual sound on the downstream side of the secondary sound generator 3, Based on the received sound signal of the sound receiver 5 for evaluation, the secondary sound creating means 7 outputs the output signal for generating the secondary sound (that is, at the interference point with the subsequent sound to be muted predicted from the residual sound). The secondary sound generator 3 generates a secondary sound having a phase opposite to that of the sound to be silenced and having the same amplitude.
Signal to be generated).

Similarly, based on the sound reception signal of the evaluation sound receiver 5, the adapting means 8 adjusts the signal creating operation of the secondary sound creating means 7 under the set characteristic Cs, thereby increasing the volume of the muted sound. (Reduce the remaining volume). The adaptation means 8
The setting characteristic Cs of is a characteristic set in consideration of the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5, and is based on the sound reception signal of the evaluation sound receiver 5. The purpose is to compensate for the positional difference in the acoustic transmission between the secondary sound generator 3 and the evaluation sound receiver 5 in adjusting the signal creating operation of the secondary sound creating means 7.

The acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 changes with the change of the damper opening θ. By correcting the setting characteristic Cs of the means 8 by the correcting means 10 according to the detected damper opening θ, the setting characteristic Cs of the adapting means 8 is corrected.
In accordance with the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 at that time, whereby the adjustment function of the adaptation means 8 with respect to the secondary sound creating means 7 is adjusted by the damper. Properly maintain regardless of the change in the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 due to the change in the opening degree θ,
The effect of increasing the volume is kept high.

[Operation of Fifth Characteristic Configuration] In the fifth characteristic configuration (see FIG. 2), the sound receiving device 5 for evaluation is provided downstream of the secondary sound generator 3 as in the case of the fourth characteristic structure. In contrast to receiving the residual sound, the secondary sound creating means 7 creates an output signal for secondary sound generation based on the received sound signal of the evaluation sound receiver 5.

Based on the output signal of the secondary sound creating means 7, the howling preventing means 9 sets the sound receiving signal of the evaluation sound receiver 5 which is input to the secondary sound creating means 7 to the setting characteristic C.
By adjusting under s', howling due to the secondary sound being taken in by the evaluation sound receiver 5 is prevented. The setting characteristic Cs ′ of the howling prevention means 9 is a characteristic set in consideration of the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5, and the secondary sound creation In order to prevent howling by removing the amount of the secondary sound taken in by the evaluation sound receiver 5 from the sound reception signal of the evaluation sound receiver 5 given to the means 7, the secondary sound by the evaluation sound receiver 5 It is for the purpose of compensating for the positional difference in acoustic transmission between the take-in position and the secondary sound generation position by the secondary sound generator 3.

The acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 changes with the change of the damper opening θ, whereas the howling as the characteristic portion X is changed. The setting characteristic Cs ′ of the preventing means 9 is corrected by the correcting means 10 according to the detected damper opening θ, so that the setting characteristic Cs ′ of the howling preventing means 9 can be changed from time to time to the secondary sound generator 3.
According to the acoustic transfer characteristic C between the sound receiving device 5 for evaluation and the sound receiving device 5 for evaluation, the adjustment function of the howling prevention means 9 for the sound reception signal of the sound receiving device 5 for evaluation is changed by changing the damper opening θ. The sound transmission characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 is appropriately maintained regardless of the change, and the howling prevention effect, and by extension, the silencing performance is maintained high.

[Operation of Sixth Characteristic Configuration] In the sixth characteristic configuration (see FIG. 3), the reference sound receiver 4 receives the sound to be muted on the upstream side of the secondary sound generator 3. , The secondary sound creating means 7 based on the sound reception signal of the reference sound receiver 4.
Is an output signal for generating a secondary sound under the set characteristic Bs' (that is, at an interference point with the sound deadening target sound that has progressed downstream from the sound receiving point of the reference sound receiver 4) is in a phase opposite to the sound deadening target sound. Then, a signal for causing the secondary sound generator 3 to generate a secondary sound having the same amplitude is created.

The setting characteristic B of the secondary sound creating means 7
s ′ is a characteristic set in consideration of the acoustic transfer characteristic B between the reference sound receiver 4 and the secondary sound generator 3, and is a secondary sound based on the sound reception signal of the reference sound receiver 4. This is for the purpose of compensating for the positional difference in the acoustic transmission between the reference sound receiver 4 and the secondary sound generator 3 in creating the sound generation signal.

The acoustic transfer characteristic B between the reference sound receiver 4 and the secondary sound generator 3 changes with the change of the damper opening θ. By correcting the set characteristic Bs ′ of the next sound creating means 7 by the correcting means 10 according to the detected damper opening θ, the secondary sound creating means 7 is obtained.
The setting characteristic Bs ′ of B is adjusted to the acoustic transfer characteristic B between the reference sound receiver 4 and the secondary sound generator 3 at any given time. , The sound transmission characteristic B between the reference sound receiver 4 and the secondary sound generator 3 due to the change of the damper opening θ is appropriately maintained and the silencing performance is maintained high.

[Operation of Seventh Characteristic Configuration] In the seventh characteristic configuration (see FIG. 4), the driving state detection means 13 drives the drive device 12 which is a source of the muffling target sound as information for determining the muffling target sound. The state is detected, and on the other hand, based on the detection signal of the drive state detecting means 13, the secondary sound producing means 7 outputs the output signal for generating the secondary sound (that is, is generated by the drive device 13 and proceeds to the downstream side). A signal that causes the secondary sound generator 3 to generate a secondary sound having an opposite phase and the same amplitude at the interference point with the muffling target sound) is created.

Further, in contrast to the evaluation sound receiver 5 detecting the residual sound at the sound receiving point, the adaptation means 8 produces the secondary sound based on the sound reception signal of the evaluation sound receiver 5. By adjusting the signal generating operation of the means 7 in a feedback control manner under the set characteristic Cs, the muting volume is increased (the remaining volume is decreased). The setting characteristic Cs of the adaptation means 8 is a characteristic set in consideration of the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5, and the evaluation sound receiver 5 is used. By adjusting the signal creating operation of the secondary sound creating means 7 on the basis of the sound receiving signal of, the purpose is to compensate for the positional difference in the acoustic transmission between the secondary sound generator 3 and the evaluation sound receiver 5. is there.

The acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 changes with the change of the damper opening θ. By correcting the setting characteristic Cs of the means 8 by the correcting means 10 according to the detected damper opening θ, the setting characteristic Cs of the adapting means 8 is corrected.
In accordance with the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 at that time, whereby the adjustment function of the adaptation means 8 with respect to the secondary sound creating means 7 is adjusted by the damper. Properly maintain regardless of the change in the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 due to the change in the opening degree θ,
The effect of increasing the volume is kept high.

[Operation of Eighth Characteristic Configuration] In the eighth characteristic structure (see FIG. 5), as in the seventh characteristic structure described above, the driving state detecting means 13 detects the sound to be muted as information for determining the sound to be muted. Detects the drive state of the drive device 12 that is the source,
On the other hand, based on the detection signal of the driving state detecting means 13, the secondary sound creating means 7 outputs the secondary sound under the set characteristic Ds (that is, is generated by the driving device 12 and proceeds to the downstream side). A signal that causes the secondary sound generator 3 to generate a secondary sound having an opposite phase and the same amplitude at the interference point with the muffling target sound) is created.

The setting characteristic D of the secondary sound creating means 7
s is a characteristic that is set in consideration of the acoustic transfer characteristic D between the drive device 12 that is the source of the sound to be muted and the secondary sound generator 3, and is based on the detection signal of the driving state detection means 13. The purpose is to compensate the positional difference in the acoustic transmission between the drive device 12 that is the source of the sound to be muted and the secondary sound generator 3 in creating the secondary sound generation signal.

Then, as the damper opening θ is changed, the acoustic transfer characteristic D between the drive device 12 which is the source of the sound to be muted and the secondary sound generator 3 is changed. By correcting the setting characteristic Ds of the secondary sound creating means 7 as X by the correcting means 10 according to the detected damper opening θ, the setting characteristic Ds of the secondary sound creating means 7 is changed to the driving device 12 at each time. According to the acoustic transfer characteristic D with the secondary sound generator 3, the signal creating function of the secondary sound creating means 7 is changed so that the drive device 12 and the secondary sound are accompanied by the change of the damper opening θ. The sound deadening performance is maintained at a high level by maintaining it properly regardless of the change in the acoustic transfer characteristic D with the generator 3.

[0038]

【The invention's effect】

[Effects of First Characteristic Configuration] According to the first characteristic configuration of the present invention, as a detection configuration of the opening degree detection means, a configuration in which the damper opening degree is detected from the outside of the air duct can be easily adopted. The problem with the conventional device described above in (a) in which the sensor for detecting the airflow velocity is arranged in the air duct, that is, the problem that the detection configuration causes the generation of wind noise and becomes a new noise source. It is possible to avoid the problem that the detection structure is likely to malfunction due to being exposed to the air flow.

Further, since the correction is performed based on the detected damper opening, the problem in the conventional device of the above-mentioned (B) that generates the monitor sound, that is, the monitor sound becomes a new noise and the overall noise becomes large. It is possible to avoid the problem and the problem that the monitor signal transmitting means and the time difference detecting means are required, which complicates the structure of the control means, makes the manufacturing difficult and increases the device cost. In particular, the damper has an operational purpose. Therefore, a device that is originally provided with an opening detection means (for example, a remote-controlled automatic damper, a variable air volume device (VAV), or
In the case of a constant air volume device (CAV) or the like), the correction in the present invention is performed by using the damper opening detected by the opening detecting means, thereby simplifying the device configuration. .

That is, according to the first characterizing configuration of the present invention, the control means can control the change of the acoustic transfer characteristics due to the change of the damper opening degree without inducing the above-mentioned problems that occur in the conventional device. The setting characteristic of the characteristic portion can be corrected, and by this correction, the control operation of the control means can be properly maintained and good silencing performance can be maintained.

[Effect of Second Characteristic Configuration] According to the second characteristic configuration of the present invention, the sound reception signal of the reference sound receiver positioned upstream of the secondary sound generator and the secondary sound generator. The sound between the secondary sound generator and the evaluation sound receiver due to the change of the damper opening in the form in which the muffling control is executed based on the sound reception signal of the evaluation sound receiver that is located on the downstream side. With respect to the change of the transfer characteristic, the setting characteristic of the adapting means can be corrected without deriving the above-mentioned problems that have occurred in the conventional device, and by this correction, the adjusting function of the adapting means can be appropriately maintained, It is possible to maintain the effect of increasing the sound deadening level high.

[Effect of Third Characteristic Configuration] According to the third characteristic configuration of the present invention, the muffling control is executed based on the sound reception signal of the reference sound receiver located upstream of the secondary sound generator. In the form, with respect to the change of the acoustic transfer characteristic between the reference sound receiver and the secondary sound generator due to the change of the damper opening, without deriving the above-mentioned problems that have occurred in the conventional device, The setting characteristic of the howling prevention means can be corrected, and by this correction, the adjusting function of the howling prevention means can be properly maintained, and the howling prevention effect, and by extension, the silencing performance can be maintained high.

[Effect of Fourth Characteristic Configuration] According to the fourth characteristic configuration of the present invention, the muffling control is executed based on the sound reception signal of the evaluation sound receiver which is located on the downstream side of the secondary sound generator. In the form, with respect to the change of the acoustic transfer characteristic between the secondary sound generator and the sound receiver for evaluation due to the change of the damper opening, without deriving the above-mentioned problems that occurred in the conventional device, The setting characteristic of the adapting means can be corrected, and by this correction, the adjusting function of the adapting means can be appropriately maintained, and the effect of increasing the sound volume can be maintained high.

[Effect of Fifth Characteristic Configuration] According to the fifth characteristic configuration of the present invention, the muffling control is executed based on the sound reception signal of the evaluation sound receiver which is located downstream of the secondary sound generator. In the form, with respect to the change of the acoustic transfer characteristic between the secondary sound generator and the sound receiver for evaluation due to the change of the damper opening, without deriving the above-mentioned problems that occurred in the conventional device, The setting characteristic of the howling prevention means can be corrected, and by this correction, the adjusting function of the howling prevention means can be properly maintained, and the howling prevention effect, and by extension, the silencing performance can be maintained high.

[Effect of Sixth Characteristic Configuration] According to the sixth characteristic configuration of the present invention, the sound deadening control is executed based on the sound reception signal of the reference sound receiver located upstream of the secondary sound generator. In the form, with respect to the change of the acoustic transfer characteristic between the reference sound receiver and the secondary sound generator due to the change of the damper opening, without deriving the above-mentioned problems that have occurred in the conventional device, The setting characteristic of the secondary sound creating means can be corrected, and by this correction, the signal creating function of the secondary sound creating means can be appropriately maintained, and the silencing performance can be maintained high.

[Effect of Seventh Characteristic Configuration] According to the seventh characteristic structure of the present invention, the detection signal of the drive state detecting means for detecting the drive state of the drive device which is the source of the sound to be muted, and the secondary sound. Between the secondary sound generator and the evaluation sound receiver due to the change of the damper opening, in the form of executing the silencing control based on the sound reception signal of the evaluation sound receiver which is located on the downstream side of the generator. With respect to the change in the acoustic transfer characteristics of the device, the setting characteristics of the adaptive means can be corrected without deriving the above-mentioned problems that occurred in the conventional device, and the correction function of the adaptive means can be properly maintained by this correction. The effect of increasing the volume of the sound is kept high.

[Effect of Eighth Characteristic Configuration] According to the eighth characteristic structure of the present invention, the muffling control is performed based on the detection signal of the drive state detecting means for detecting the drive state of the drive device which is the source of the sound to be silenced. In the form to be executed, with respect to the change of the acoustic transfer characteristic between the drive device and the secondary sound generator due to the change of the damper opening, the various problems as described above that have occurred in the conventional device are not caused. The setting characteristic of the secondary sound creating means can be corrected, and by this correction, the signal creating function of the secondary sound creating means can be appropriately maintained, and the silencing performance can be maintained high.

[0048]

【Example】

[First Embodiment] FIG. 1 shows an embodiment of the present invention according to claims 1, 2 and 3, wherein 1 is the adjusted air when the air adjusted by an air conditioner is sent to an air conditioning target area by the operation of a fan. Is a blower duct that guides the air-conditioning target area. The blower duct 1 is provided with a damper 2 used for adjusting the air volume, adjusting the static pressure of the air passage, or adjusting the area pressure of the target area for air-conditioning.

The blower duct 1 is equipped with an active muffler for the duct which prevents the operating noise of the air conditioner and the fan from leaking to the target area for air conditioning through the blower duct 1.
As the device configuration, a secondary sound generator 3 is provided in the air duct 1, a reference sound receiver 4 is provided upstream of the secondary sound generator 3, and further downstream than the secondary sound generator 3. The sound receiver 5 for evaluation is provided on the side, and based on the sound reception signals of the sound receivers 4 and 5 for reference and evaluation, noise to be silenced propagating in the air duct 1 (operation noise of an air conditioner or a fan). 2) is provided with a control device 6 for causing the secondary sound generator 3 to generate a secondary sound that causes interference in the opposite phase and with the same amplitude.

The control device 6 has, as its constituent means, an output signal for generating a secondary sound (that is, a reference signal) to the secondary sound generator 3 based on the sound reception signal of the reference sound receiver 4. The secondary sound generator 3 generates a secondary sound having an opposite phase and the same amplitude at the interference point with the sound deadening target sound that has progressed downstream from the sound receiving point of the sound receiver 4. The secondary sound creating means 7 for creating a signal) and the sound receiving signal of the evaluation sound receiver 5 are used to adjust the signal creating operation of the secondary sound creating means 7 under the setting characteristic Cs. Based on the output signal of the adaptation means 8 for increasing the volume of sound at the sound receiving point of the sound receiver 5 and the secondary sound creation means 7, the reception of the reference sound receiver 4 input to the secondary sound creation means 7 Set sound signal Characteristic Bs
The reference sound receiver 4 is equipped with howling prevention means 9 for preventing howling caused by taking in a secondary sound by adjusting below.

The adapting means 8 has a filter 8a for processing the sound receiving signal of the reference sound receiver 4 with the setting characteristic Cs and applying it to the adaptive processing unit 8b. The processed signal of this filter 8a and the evaluation sound receiving are provided. The adaptive processing unit 8b adjusts the signal creating operation of the secondary sound creating unit 7 based on the received sound signal of the device 5 according to a predetermined logic to maximize the mute volume.

The howling prevention means 9 has a filter 9a for processing the output signal of the secondary sound producing means 7 with the set characteristic Bs, and the processed signal of this filter 9a is used as the sound reception signal of the reference sound receiver 4. By adding the subtraction process to
The secondary sound taken in by the reference sound receiver 4 is removed from the sound reception signal of the reference sound receiver 4 to prevent howling.

That is, the setting characteristic Cs of the adaptive means 8 (the setting characteristic of the filter 8a) is the acoustic transfer characteristic C between the secondary sound generator 3 and the evaluation sound receiver 5 in the air duct 1, and It is set in consideration of the characteristics of the evaluation sound receiver 5 and the signal transmission characteristics in the control device 6 related to this, and the secondary sound creating means 7 is based on the sound reception signal of the evaluation sound receiver 5. This characteristic is intended to compensate for the positional difference in the acoustic transmission between the secondary sound generator 3 and the evaluation sound receiver 5 in adjusting the signal generating operation.

The setting characteristic B of the howling prevention means 9
s (setting characteristic of the filter 9a) is the acoustic transfer characteristic B between the reference sound receiver 4 and the secondary sound generator 3 in the air duct 1 and the reference sound receiver 4 related thereto. The characteristics and the signal transmission characteristics in the control device 6 are set in consideration, and the secondary sound is generated by the reference sound receiver 4 from the sound reception signal of the reference sound receiver 4 given to the secondary sound creating means 7. The purpose is to compensate for the positional difference in acoustic transmission between the secondary sound capturing position by the reference sound receiver 4 and the secondary sound generating position by the secondary sound generator 3 in removing the captured sound component. Is the characteristic.

The control device 6 includes the above-mentioned respective constituent means 7, 8,
In addition to 9, the adaptive means 8 and the howling prevention means 9 are respectively set as the characteristic part X to be corrected, and the setting characteristic Cs of the adaptive means 8 and the setting characteristic B of the howling prevention means 9 are set.
The correction unit 10 includes a correction unit 10 that corrects s, and the correction unit 10 includes a characteristic Cs of the adaptation unit 8 and an opening θ of the damper 2.
And a storage unit 10a that stores a set correlation Fc for and a set correlation Fb for the characteristic Bs of the howling prevention means 9 and the opening degree θ of the damper 2, and
According to the damper opening degree θ detected by the opening degree detection means 11, the set characteristic Cs of the adaptation means 8 and the set characteristic Bs of the howling prevention means 9 are respectively set correlation F.
The correction is performed so as to correspond to the detected damper opening θ on c and Fb.

That is, the acoustic transmission characteristic in the air duct changes with the change of the damper opening θ, but the optimum characteristic Cs and the damper opening Cs of the adapting means 8 which changes with the damper opening θ are previously tested. By grasping the correlation with θ and the correlation between the optimum characteristic Bs of the howling prevention means 9 that also changes with the damper opening θ and the damper opening θ, these correlations are set to the above-mentioned correlations Fc and Fb. As described above, and as described above, the setting characteristic Cs of the adaptive means 8 and the setting characteristic of the howling prevention means 9 are set in accordance with the detected damper opening θ based on these set correlations Fc and Fb. By correcting Bs, the adjusting function of the adapting means 8 for the secondary sound creating means 7 and the reference sound reception regardless of the change of the acoustic transfer characteristics due to the change of the damper opening θ. It is as maintain proper adjustment function howling prevention means 9 for 4 received sound signal.

[Second Embodiment] FIG. 2 shows claims 1, 4 and 5
An embodiment of the present invention will be described. Those having the same functions as those of the above-described first embodiment will be designated by the same reference numerals and description thereof will be omitted.

The active muffler for a duct shown in the second embodiment omits the reference sound receiver 4 arranged upstream of the secondary sound generator 3, and the secondary sound producing means 7 is While the evaluation sound receiver 5 receives the residual sound at the sound receiving point, the output signal for generating the secondary sound (that is, from the residual sound) is generated based on the sound reception signal of the evaluation sound receiver 5. A signal that causes the secondary sound generator 3 to generate a secondary sound having a phase opposite to that of the noise suppression target sound and having the same amplitude at the predicted interference point with the subsequent noise suppression target sound.

Further, the adapting means 8 adjusts the signal creating operation of the secondary sound creating means 7 based on the sound receiving signal of the evaluation sound receiving device 5 under the set characteristic Cs, so that the evaluation sound receiving device. 5
Of the sound receiver 5 for evaluation is processed by the set characteristic Cs and provided to the adaptive processing unit 8b.
Based on the processed signal of a ′ and the received sound signal of the evaluation sound receiver 5, the adaptive processing unit 8b uses the predetermined logic to generate the secondary sound generating means 7
The signal creating operation of is adjusted to maximize the volume of the sound.

The howling prevention means 9 adjusts the sound reception signal of the evaluation sound receiver 5 input to the secondary sound creation means 7 based on the output signal of the secondary sound creation means 7 under the set characteristic Cs'. By doing so, howling due to the secondary sound being taken in by the evaluation sound receiver 5 is prevented, and a filter 9a 'for processing the output signal of the secondary sound creating means 7 with the setting characteristic Cs' is provided. By subtracting the received signal of the evaluation sound receiver 5 with the processed signal of the filter 9a ′, the secondary sound of the evaluation sound receiver 5 is changed from the sound reception signal of the evaluation sound receiver 5. The taken-in portion is removed, thereby preventing howling.

That is, in the second embodiment, the setting characteristic Cs of the adaptive means 8 (setting characteristic of the filter 8a ') and the setting characteristic Cs' of the howling prevention means 9 (setting characteristic of the filter 9a') are The acoustic transfer characteristics C between the secondary sound generator 3 and the evaluation sound receiver 5 in the air duct 1, and the characteristics of the evaluation sound receiver 5 and the related characteristics in the control device 6, respectively. The setting is made in consideration of the signal transfer characteristics, and in adjusting the signal creating operation of the secondary sound creating means 7 based on the sound receiving signal of the evaluation sound receiver 5, the secondary sound creating means 7 is also controlled. In removing the secondary sound taken in by the evaluation sound receiver 5 from the sound reception signal of the evaluation sound receiver 5 to be provided, in terms of acoustic transmission between the secondary sound generator 3 and the evaluation sound receiver 5. This is a characteristic aimed at compensating for the position difference of.

On the other hand, the correction means 10 sets each of the adaptation means 8 and the howling prevention means 9 as the characteristic part X to be corrected, the setting characteristic Cs of the adaptation means 8 and the setting characteristic Cs' of the howling prevention means 9. To correct the
The setting correlation Fc between the characteristic Cs of the adaptation means 8 and the damper opening θ, and the characteristic C of the howling prevention means 9
The storage unit 10a stores a set correlation Fc ′ for s ′ and the damper opening θ, and the opening detection unit 1
1, the setting characteristic Cs of the adaptive means 8 and the setting characteristic Cs ′ of the howling prevention means 9 are detected on the respective setting correlations Fc and Fc ′. The configuration is such that correction is made to correspond to θ.

That is, in response to the change of the damper opening θ with respect to the change of the acoustic transfer characteristic in the air duct, the adaptive means which changes with the damper opening θ by a test or the like in advance as in the first embodiment. 8 Optimal characteristics Cs and damper opening θ
And the optimum characteristic Cs ′ of the howling prevention means 9 that changes depending on the damper opening θ and the damper opening θ.
And the correlations are stored in the storage unit 10a as the above-mentioned set correlations Fc and Fc ′, and, as described above, these set correlations Fc and Fc,
By correcting the setting characteristic Cs of the adaptation means 8 and the setting characteristic Cs' of the howling prevention means 9 according to the detected damper opening θ based on Fc ′, the change of the acoustic transfer characteristic due to the change of the damper opening θ. Regardless of the secondary sound creation means 7
Adjustment function of the adaptation means 8 for the
The adjusting function of the howling prevention means 9 with respect to the sound receiving signal is properly maintained.

[Third Embodiment] FIG. 3 shows an embodiment of the present invention according to claims 1 and 6, and parts having the same functions as those of the above-mentioned embodiments are designated by the same reference numerals and the description thereof will be omitted.

The active muffler for a duct shown in the third embodiment is of a simple type in which the evaluation sound receiver 5 and the adapting means 8 are omitted, and the secondary sound producing means 7 is a reference sound receiving device. Sound instrument 4
Is receiving the sound to be muted, the output signal for generating the secondary sound (the sound reception of the reference sound receiver 4 is received under the set characteristic Bs ′ based on the sound reception signal of the reference sound receiver 4). At the point of interference with the noise reduction target sound that has progressed downstream from the point, the secondary sound generator 3 generates a secondary sound that has the same amplitude as the noise reduction target sound in the opposite phase.
Signal to be generated).

The howling prevention means 9 determines the sound reception signal of the reference sound receiver 4 to be input to the secondary sound generation means 7 based on the output signal of the secondary sound generation means 7 under the set characteristic Bs. The adjustment also prevents howling due to the secondary sound being taken in by the reference sound receiver 4, and has a filter 9a for processing the output signal of the secondary sound creating means 7 with the setting characteristic Bs, By subtracting the received signal of the reference sound receiver 4 with the processed signal of the filter 9a, the secondary sound taken in by the reference sound receiver 4 from the received signal of the reference sound receiver 4 is subtracted. Is removed, thereby preventing howling.

That is, in the third embodiment, the setting characteristic Bs' of the secondary sound producing means 7 and the setting characteristic Bs of the howling prevention means 9 (setting characteristic of the filter 9a) are respectively in the air duct 1. Considering the acoustic transfer characteristic B between the reference sound receiver 4 and the secondary sound generator 3 in FIG. 1 and the related characteristics of the reference sound receiver 4 and the signal transfer characteristics in the control device 6. The reference sound receiver 4 to be provided to the secondary sound creating means 7 when the output signal for generating the secondary sound is created based on the sound reception signal of the reference sound receiver 4. By removing the amount of the secondary sound taken in by the reference sound receiver 4 from the sound reception signal of, it is possible to compensate for the positional difference in the acoustic transmission between the reference sound receiver 4 and the secondary sound generator 3. This is the desired characteristic.

On the other hand, the correcting means 10 is the secondary sound creating means 7
And each of the howling prevention means 9 as the characteristic part X to be corrected, the set characteristic Bs ′ of the secondary sound creating means 7,
Also, the setting characteristic Bs of the howling prevention means 9 is corrected, and the setting correlation Fb ′ between the characteristic Bs ′ of the secondary sound creating means 7 and the damper opening θ and the characteristic Bs of the howling prevention means 9 are corrected. And a damper opening θ, the storage unit 10a stores a set correlation Fb, and the setting characteristic Bs of the secondary sound creating means 7 is set according to the damper opening θ detected by the opening detecting means 11. And the setting characteristic Bs of the howling prevention means 9 is corrected to correspond to the detected damper opening θ on the setting correlations Fb ′ and Fb.

In this correction mode, the correlation between the optimum characteristic Bs ′ of the secondary sound producing means 7 which changes with the damper opening θ and the damper opening θ, and the howling prevention means which changes with the damper opening θ. The correlation between the optimum characteristic Bs of 9 and the damper opening θ is grasped in advance by a test or the like, and these correlations are stored in the storage unit 10a as the above-mentioned set correlations Fb ′ and Fb. This is similar to each embodiment.

[Fourth Embodiment] FIG. 4 shows an embodiment of the present invention according to claims 1 and 7, and those having the same functions as those of the above-mentioned embodiments are designated by the same reference numerals and the description thereof will be omitted.

The active muffler for a duct shown in the fourth embodiment is provided with a reference sound receiver 4 as a means for judging the sound to be muffled.
Instead of the above, a drive state detection means 13 for detecting the drive state (for example, the number of revolutions) of the drive device 12 (air conditioner, fan, etc.) that is the source of the sound to be muted is provided, and the secondary sound is created. The means 7 is an output signal for generating a secondary sound (that is, the drive device 1 based on the detection signal of the drive state detection means 13).
(2) A signal that causes the secondary sound generator 3 to generate a secondary sound that has the same amplitude as the noise to be silenced at the interference point with the noise to be muted that has occurred in 2 and has progressed downstream. To do.

Further, the adapting means 8 adjusts the signal creating operation of the secondary sound creating means 7 based on the sound receiving signal of the evaluation sound receiver 5 under the set characteristic Cs, so that the evaluation sound receiver. 5
In order to increase the mute volume at the sound receiving point of, the filter 8a ″ for processing the detection signal of the driving state detecting means 13 with the setting characteristic Cs and applying it to the adaptive processing unit 8b is provided. The adaptive processing unit 8b adjusts the signal creating operation of the secondary sound creating unit 7 by a predetermined logic based on the processed signal and the sound receiving signal of the evaluation sound receiver 5 to maximize the mute volume.

That is, in the fourth embodiment, the setting characteristic Cs of the adapting means 8 (setting characteristic of the filter 8a ″) is the secondary sound generator 3 and the evaluation sound receiver 5 in the air duct 1.
Is set in consideration of the sound transfer characteristic C between the sound receiver 5 for evaluation and the characteristic of the sound receiver 5 for evaluation related thereto and the signal transfer characteristic in the control device 6, and By adjusting the signal creating operation of the secondary sound creating means 7 based on the received sound signal, it is intended to compensate for the positional difference in the acoustic transmission between the secondary sound generator 3 and the evaluation sound receiver 5. It is a characteristic.

On the other hand, the correction means 10 corrects the setting characteristic Cs of the adaptation means 8 by using the adaptation means 8 as the characteristic part X to be corrected, and the characteristics Cs of the adaptation means 8 and the damper opening θ. Storage unit 1 for storing the set correlation Fc of
0a, and according to the detected damper opening degree θ of the opening degree detection means 11, the setting characteristic Cs of the adaptation means 8 is corrected to correspond to the detected damper opening degree θ on the set correlation Fc. .

In this correction mode, the correlation between the optimum characteristic Cs of the adaptive means 8 which changes depending on the damper opening θ and the damper opening θ is grasped in advance by a test or the like, and this correlation is set to the above-mentioned set correlation. The fact that the relation Fc is stored in the storage unit 10a is the same as in the above-described embodiments.

[Fifth Embodiment] FIG. 5 shows an embodiment of the present invention according to claims 1 and 8. The same functions as those of the above-mentioned embodiments are designated by the same reference numerals and the description thereof will be omitted.

In the active muffler for duct shown in the fifth embodiment, the drive state detecting means 1 for detecting the drive state of the drive device 12 which is the source of the sound to be silenced is used in place of the reference sound receiver 4.
3 is provided and the evaluation sound receiver 5 is omitted, and the secondary sound generating means 7 is for generating a secondary sound under the set characteristic Ds based on the detection signal of the drive state detecting means 13. Output signal (at the point of interference with the noise reduction target sound generated in the drive device 12 and progressing to the downstream side, a secondary sound having the same amplitude as that of the noise reduction target sound but having the opposite phase to the noise reduction target sound is output to the secondary sound generator 3. Signal to be generated).

That is, in the fifth embodiment, the setting characteristic Ds of the secondary sound creating means 7 is the acoustic transfer characteristic between the drive device 12 which is the source of the sound to be muted and the secondary sound generator 3. D and the related signal transmission characteristics in the control device 6 are set in consideration of the drive state detecting means 1
In the output signal for generating the secondary sound based on the detection signal of No. 3, the characteristic aiming to compensate the positional difference in the acoustic transmission between the drive device 12 and the secondary sound generator 3. is there.

On the other hand, the correcting means 10 is the secondary sound creating means 7
Is used as the characteristic portion X to be corrected to correct the setting characteristic Ds of the secondary sound creating means 7, and the setting correlation Fd between the characteristic Ds of the secondary sound creating means 7 and the damper opening θ.
And a setting characteristic Ds of the secondary sound creating means 7 corresponding to the detected damper opening degree θ on the setting correlation Fd according to the detected damper opening degree θ of the opening degree detecting means 11. The configuration is such that it is corrected to what does.

In this correction mode, the correlation between the optimum characteristic Ds of the secondary sound producing means 7 which changes depending on the damper opening θ and the damper opening θ is grasped in advance by a test or the like,
This correlation is set as the above-described set correlation Fd in the storage unit 1.
The point to be stored in 0a is the same as in each of the above-described embodiments.

[Other Embodiments] The damper 2 in the blower duct 1 may be installed at any position, such as the reference sound receiver 4, the secondary sound generator 3, the evaluation sound receiver 5 and the like. The relative positional relationship with is not specified.

The secondary sound generator 3 is not limited to one, and a plurality of secondary sound generators may be provided. Similarly, the reference sound receiver 4 and the evaluation sound receiver 5 are also provided. The configuration is not limited to one, and a plurality of devices may be provided.

The opening detecting means 11 detects the rotation angle of the damper rotating shaft in a state of being linked to the damper rotating shaft, or detects the damper opening from the damper operation signal in a remotely operated damper. It is possible to adopt various formats such as a format for performing.

In the present invention according to claim 1, the characteristic portion X to be corrected by the correcting means 10 sets the characteristic in consideration of the acoustic transfer characteristic in the blower duct 1 as the setting characteristic thereof. For example, the control means 6 may have any function and is not limited to the adaptation means 8, the howling prevention means 9, and the secondary sound generation means 7 as in the above-described embodiment.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a device configuration diagram showing a first embodiment.

FIG. 2 is a device configuration diagram showing a second embodiment.

FIG. 3 is a device configuration diagram showing a third embodiment.

FIG. 4 is a device configuration diagram showing a fourth embodiment.

FIG. 5 is a device configuration diagram showing a fifth embodiment.

FIG. 6 is a device configuration diagram showing a conventional example.

FIG. 7 is a device configuration diagram showing another conventional example.

[Explanation of symbols]

 2 Damper 1 Blower duct 3 Secondary sound generator 6 Control means θ Damper opening 11 Opening detecting means X Characteristic part 10 Correcting means 4 Reference sound receiver 5 Evaluation sound receiver 7 Secondary sound creating means Cs, Cs 'setting characteristic 8 Adapting means Bs, Bs' setting characteristic 9 Howling prevention means 12 Driving device 13 Driving state detecting means Ds setting characteristic

Claims (8)

[Claims] 1. A secondary sound generator (3) is provided in a blower duct (1) having a damper (2) interposed between the blower duct (1) and a noise reduction target sound propagating in the blower duct (1) in the opposite phase. An active muffler for a duct, comprising: a control means (6) for causing a secondary sound to be generated in the secondary sound generator (3) to be interfered in an amplitude state, the opening (θ) of the damper (2). And the set characteristic of the characteristic part (X) of the control means (6) for detecting the opening degree detection means (11) according to the detected damper opening degree (θ) of the opening degree detection means (11). An active silencer for a duct provided with a correction means (10). 2. A reference sound receiver (4) is provided on the upstream side of the secondary sound generator (3) in the air duct (1), and further than the secondary sound generator (3). An evaluation sound receiver (5) is provided on the downstream side, and the control means (6) is a secondary device for the secondary sound generator (3) based on a sound reception signal of the reference sound receiver (4). Secondary sound creating means (7) for creating an output signal for sound generation, and a signal creating operation of the secondary sound creating means (7) is set based on the sound receiving signal of the evaluation sound receiver (5). An adjusting unit (8) for increasing the mute volume by adjusting under the characteristic (Cs), and the correcting unit (10) uses the adjusting unit (8) as the characteristic unit (X) to be corrected. The duct according to claim 1, wherein the setting characteristic (Cs) of the adaptation means (8) is corrected according to the detected damper opening (θ). Use active silencer. 3. A reference sound receiver (4) is provided upstream of the secondary sound generator (3) in the blower duct (1), and the control means (6) controls the reference sound receiver. Secondary sound creating means (7) for creating an output signal for secondary sound generation to the secondary sound generator (3) based on the received sound signal of the device (4), and the secondary sound creating means (7) ), The reference sound receiver (4) is input to the secondary sound creating means (7) based on the output signal of
And a howling prevention means (9) for preventing howling by adjusting the sound reception signal of the howling prevention means (9) under the set characteristic (Bs). The active muffler for duct according to claim 1 or 2, wherein the characteristic part (X) is configured to correct the set characteristic (Bs) of the howling prevention means (9) according to the detected damper opening degree (θ). . 4. An evaluation sound receiver (5) is provided downstream of the secondary sound generator (3) in the blower duct (1), and the control means (6) receives the evaluation sound. Secondary sound creating means (7) for creating an output signal for secondary sound generation to the secondary sound generator (3) based on the sound receiving signal of the device (5), and the evaluation sound receiver (5) ) Adjusting means for adjusting the signal creating operation of the secondary sound creating means (7) under the set characteristic (Cs) based on the received sound signal of (1) to increase the volume of the sound deadening. (10) corrects the set characteristic (Cs) of the adaptive means (8) according to the detected damper opening degree (θ) by using the adaptive means (8) as the characteristic portion (X) to be corrected. The active muffler for a duct according to claim 1, which is configured. 5. An evaluation sound receiver (5) is provided downstream of the secondary sound generator (3) in the blower duct (1), and the control means (6) receives the evaluation sound reception. Secondary sound creating means (7) for creating an output signal for secondary sound generation to the secondary sound generator (3) based on the received sound signal of the device (5), and the secondary sound creating means (7) ), The evaluation sound receiver (5) is input to the secondary sound creating means (7) based on the output signal of
And a howling prevention means (9) for preventing howling by adjusting the sound reception signal of the device under the set characteristic (Cs'), and the correction means (6) is the howling prevention means (9).
Is set as the characteristic part (X) to be corrected, and the setting characteristic (Cs ′) of the howling prevention means (X) is corrected according to the detected damper opening (θ).
Or the active muffler for a duct according to 4. 6. A reference sound receiver (4) is provided upstream of the secondary sound generator (3) in the blower duct (1), and the control means (6) controls the reference sound receiver. Secondary sound generating means (7) for generating an output signal for secondary sound generation to the secondary sound generator (3) under the set characteristic (Bs') based on the sound reception signal of the device (4). The correcting means (10) detects the setting characteristic (Bs ′) of the secondary sound creating means (7) by using the secondary sound creating means (7) as the characteristic part (X) to be corrected. The active muffler for a duct according to claim 1, wherein the active muffler for a duct is configured to be corrected according to a damper opening (θ). 7. A drive state detecting means (1) for detecting a drive state of a drive device (12) which is a source of generation of the sound to be muted.
3) is provided, and an evaluation sound receiver (5) is provided downstream of the secondary sound generator (3) in the blower duct (1), and the control means (6) detects the drive state. Means (13)
Secondary sound generating means (7) for generating an output signal for generating a secondary sound to the secondary sound generator (3) based on the detection signal of the sound receiving signal of the evaluation sound receiver (5). The adjusting means (8) for adjusting the signal producing operation of the secondary sound producing means (7) under the setting characteristic (Cs) to increase the volume of the sound. The adaptive means (8) is used as the characteristic portion (X) to be corrected, and the setting characteristic (Cs) of the adaptive means (8) is corrected according to the detected damper opening (θ). 1. An active silencer for a duct according to 1. 8. A drive state detecting means (1) for detecting a drive state of a drive device (12) which is a source of generation of the noise reduction target sound.
3) is provided, and the control means (6) is provided with the drive state detection means (13).
Secondary sound generating means (7) for generating an output signal for secondary sound generation to the secondary sound generator (3) under a set characteristic (Ds) based on the detection signal of the correction means (10). ) Uses the secondary sound creating means (7) as the characteristic part (X) to be corrected, and sets the setting characteristic (Ds) of the secondary sound creating means (7) to the detected damper opening (θ). The active muffler for a duct according to claim 1, wherein the active muffler is configured to be corrected accordingly.