WO2011077602A1

WO2011077602A1 - Air conditioner

Info

Publication number: WO2011077602A1
Application number: PCT/JP2010/003383
Authority: WO
Inventors: 道籏聡; 辻雅之; 八嶋昇
Original assignee: 三菱電機株式会社
Priority date: 2009-12-25
Filing date: 2010-05-20
Publication date: 2011-06-30
Also published as: CN102686951A; JP2011137560A; EP2518414A1

Abstract

Disclosed is an air conditioner which enables high-accuracy active silencing. Specifically disclosed is an air conditioner (1) provided with a housing in which an inlet port (3) and an outlet port (5) are formed, a blower fan (2) which comprises an impeller (25), a heat exchanger (4), a noise detection microphone (6) which detects noise from the blower fan (2), a control speaker (8) which outputs control sound for reducing the noise, a silencing effect detection microphone (9) which detects a silencing effect, and a signal processing unit (10) which generates the control sound on the basis of the results of the detections by the noise detection microphone (6) and the silencing effect detection microphone (9). The noise detection microphone (6) is disposed in a columnar region (A) formed by extending an inscribed circle tangent to the inner peripheries of blades of the impeller (25) in the direction of the rotation axis of the impeller (25), and provided on a stationary blade mounting member (7) of the blower fan (2).

Description

Air conditioner

The present invention relates to an air conditioner equipped with a silencer for reducing noise such as a blower fan.

In order to reduce noise as typified by driving sound of a blower fan, passive noise reduction methods such as sound absorption and sound insulation have been conventionally performed. However, these methods are effective in reducing noise in a relatively high frequency band, but are known to be ineffective in low frequency band noise such as fan rotation noise.

As an improvement measure, an active noise reduction method is used in which noise is reduced by outputting a control sound having the same amplitude and opposite phase with respect to noise from a speaker or the like and causing interference with the noise. Such an active mute method generally includes a sound receiver (such as a sensing microphone), a signal processing device composed of a digital filter and an adaptive algorithm, a sound generator (such as a control speaker), and error signal detection. And a sensor (evaluation microphone or the like). Then, a sound receiver is arranged on the downstream side of the sound source to detect sound generated from the sound source, and a control signal having the same amplitude and opposite phase as the noise is created based on the detected sound. The control signal created by the signal processing device is input to the sound generator and output as a control sound. Further, the control result of active silencing is evaluated by the error signal detection sensor arranged at the control point to be silenced, and the filter coefficient of the digital filter of the signal processing device is set so that the error signal detected by the error signal detection sensor is minimized. Update.

However, it is known that the above active silencing method cannot be silenced unless the spatial coherence of the sound is taken. In particular, in the case of a sound source with an air flow such as a blower fan, if the sound receiver is close to the sound source, coherence with the error signal detection sensor cannot be obtained due to air flow disturbance at the blower fan outlet. For this reason, it is necessary to increase the distance between the sound receiver and the sound source to reduce the influence of airflow turbulence.

In order to solve the above-described problem of the active silencing method, for example, “a network between the sound source (fan) 6 and the sound receiver (sensing microphone) 1 disposed in the flow path in the duct 5 is used. With the configuration in which the rectifying member 10 is provided, the sound radiated from the sound source 6, that is, the flow of the fluid (air) propagating the sound can be rectified so as to have a substantially uniform flow to obtain coherence. An active noise control can be effectively performed by bringing the sounder 1 close to the sound source 6 side "(for example, see Patent Document 1).
Further, for example, “a microphone 21 that detects noise generated by the fan blade 23 of the blower 20 and supplies this to the controller as a reference signal x is placed inside the rotating shaft 31 of the electric motor 30 that drives the fan blade 23 to rotate. “Provided” (see, for example, Patent Document 2) has also been proposed.

Japanese Patent Laid-Open No. 5-188976 (summary, FIG. 1) Japanese Patent Laid-Open No. 5-289777 (summary, FIG. 2)

However, since the silencer described in Patent Document 1 must sandwich a rectifying member between the blower fan and the sound receiver, the sound receiver cannot be installed directly under the fan. For this reason, the silencer described in Patent Document 1 has a problem that the system cannot be downsized. Furthermore, the silencer described in Patent Literature 1 has a problem that the cost increases because the number of parts increases.

Also, the silencer described in Patent Document 2 may come into contact with the rotating shaft where the sound receiver rotates at high speed. When the sound receiver comes into contact with a rotating shaft that rotates at a high speed, the sound receiver not only detects abnormal noise due to the contact, but also leads to failure of the sound receiver. For this reason, it is necessary to attach a sound receiver so that it may not contact a rotating shaft, and there existed a subject that installation freedom was almost lost. Furthermore, since precise attachment is required, the mechanism of the blower fan becomes complicated, and there is a problem that the cost of the blower fan increases.

The present invention has been made to solve such a problem. An air conditioner capable of performing active silencing with high accuracy without increasing the number of parts of the silencing device and without changing the mechanism of the blower fan. For the purpose of provision.

An air conditioner according to the present invention includes a housing in which an inlet and an outlet are formed, a blower fan having an impeller, a heat exchanger, and a noise detection device that detects noise generated from the blower fan, The control sound output device that outputs the control sound for reducing the noise, the mute effect detection device that detects the mute effect of the control sound, the control sound based on the detection results of the noise detection device and the mute effect detection device An air conditioner comprising: a control sound generating device that generates a control sound generating device, wherein the noise detecting device extends an inscribed circle in contact with an inner peripheral portion of a blade of the impeller in a rotation axis direction of the impeller. It is arrange | positioned at a cylindrical area | region, and is provided in the stationary member of the said ventilation fan, or the downstream of the said ventilation fan.

In the air conditioner according to the present invention, the noise detection device is disposed in a cylindrical region in which an inscribed circle that is in contact with the inner peripheral portion of the impeller extends in the rotation axis direction of the impeller, and the stationary member of the blower fan or the blower It is provided on the downstream side of the fan. Therefore, it is possible to obtain an air conditioner that can perform active silencing with high accuracy without increasing the number of parts of the silencer and without changing the mechanism of the blower fan.

It is sectional drawing which shows the structure of the air conditioner in Embodiment 1 of this invention. FIG. 3 is a front view of an air conditioner according to Embodiments 1 to 3 of the present invention. It is a bottom view of the ventilation fan in Embodiment 1 of this invention. It is sectional drawing of the ventilation fan shown in FIG. It is the figure which showed the signal processing apparatus which produces | generates the control sound of Embodiment 1 of this invention. It is a figure of the experimental result which visualized the airflow which blows off from the ventilation fan in Embodiment 1 of this invention. It is a figure which shows the circuit of the weighting means in Embodiment 1 of this invention. It is a figure which shows the coherence characteristic of the detection sound of the noise detection microphone 6 and the detection sound of the muffling effect detection microphone 9 when the noise detection microphone 6 is installed outside the cylindrical region A and the blower fan 2 is operated. It is a figure which shows the coherence characteristic of the detection sound of the noise detection microphone 6 and the detection sound of the muffling effect detection microphone 9 when the noise detection microphone 6 is installed inside the cylindrical region A and the blower fan 2 is operated. It is sectional drawing which shows another structure of the air conditioner in Embodiment 1 of this invention. It is sectional drawing which shows another structure of the air conditioner in Embodiment 1 of this invention. It is sectional drawing which shows another attachment method of the noise detection microphone in Embodiment 1 of this invention. It is sectional drawing which shows the structure of the air conditioner in Embodiment 2 of this invention. It is the figure which showed the signal processing apparatus which produces | generates the control sound of Embodiment 2 of this invention. It is a wave form diagram for demonstrating the method of calculating the noise which wants to mute from the sound after interference. It is a block diagram for demonstrating the method of estimating the control sound of Embodiment 2 of this invention. It is sectional drawing which shows another structure of the air conditioner in Embodiment 2 of this invention. It is sectional drawing which shows another structure of the air conditioner in Embodiment 2 of this invention. It is sectional drawing which shows another attachment method of the noise and the silencing effect detection microphone in Embodiment 2 of this invention. It is sectional drawing which shows the structure of the air conditioner in Embodiment 3 of this invention. It is the figure which showed the signal processing apparatus which produces | generates the control sound of Embodiment 3 of this invention.

<A. Embodiment 1>
Hereinafter, the air conditioner of this invention is demonstrated in detail using drawing.
<A-1. Configuration>
FIG. 1 is a cross-sectional view of the air conditioner 1 shown in FIG. 2 cut along a cross-section X, and is a diagram illustrating a configuration of the air conditioner 1 according to the first embodiment.

The air conditioner 1 in FIG. 1 constitutes an indoor unit. The air inlet 1 (more specifically, the casing of the air conditioner 1) has an inlet 3 at the top and a blower 5 at the lower end. Each is open.

An air flow path is formed in the air conditioner 1 so as to communicate the suction port 3 and the blowout port 5. An axial flow fan having a substantially vertical rotation axis is provided below the suction port 3 of the air flow path. The provided blower fan 2 is provided. A heat exchanger 4 that cools or heats the air by exchanging heat is disposed below the blower fan 2. The heat exchanger 4 is fixed in the housing by a heat exchanger fixing bracket 30. As indicated by the white arrow in FIG. 1, when the blower fan 2 is activated, indoor air is sucked into the air flow path in the air conditioner 1 from the suction port 3, and this intake air is present at the lower part of the blower fan 2. After cooling or heating with the heat exchanger 4, the air is blown out into the room from the outlet 5.

FIG. 3 is a bottom view of the blower fan according to Embodiment 1 of the present invention (viewed from the lower side of FIG. 1). 4 is a cross-sectional view of the blower fan 2 shown in FIG. The blower fan 2 includes an impeller 25 called a moving blade, a stationary blade 26, a stationary blade mounting member 7 to which the stationary blade 26 is attached to an outer peripheral portion, a motor (not shown), and a rotation that transmits power from the motor to the impeller 25. A shaft (not shown) is provided. 3 indicates a portion corresponding to the inner periphery of the blades of the blower fan 2 (that is, an inscribed circle in contact with the inner periphery of the blades of the impeller 25).

A motor that is a power source of the impeller 25 is provided in the stationary blade mounting member 7. The motor and the boss 27 of the impeller 25 are connected by a rotating shaft 28. Thereby, the rotation of the motor is transmitted to the impeller 25 via the rotating shaft 28, and the impeller 25 rotates. As the impeller 25 rotates, air flows (blows) in the direction indicated by the white arrow in FIG. In addition, the part shown with the oblique line in FIG. 4 has shown the part rotated at the time of the operation | movement of the ventilation fan 2. FIG. Moreover, the part without a diagonal line has shown the part (namely, immovable member) which does not rotate even when the ventilation fan 2 is operation | movement. Further, a portion corresponding to the inner periphery of the blade of the blower fan 2 (that is, an inscribed circle in contact with the inner periphery of the blade of the impeller 25) is an outer periphery of the boss portion 27. In the first embodiment, the diameter of the stationary blade mounting member 7 is formed to be substantially the same as the diameter of the boss portion 27.

Referring again to FIG. 1, noise detection for detecting the operation sound (noise) of the air conditioner 1 including the blowing sound of the blowing fan 2 is applied to the stationary blade mounting member 7 corresponding to the inner periphery of the blade of the blowing fan 2. A noise detection microphone 6 is attached as a device. That is, the noise detection microphone 6 is arranged in a cylindrical region (hereinafter referred to as a cylindrical region A) in which an inscribed circle that is in contact with the inner peripheral portion of the blade of the impeller 25 extends in the direction of the rotation axis of the impeller 25. The stationary blade mounting member 7 is configured to be independent of the rotating impeller 25 and not to rotate as shown in FIG. 4 when the blower fan 2 is operated. For this reason, the noise detection microphone 6 also does not rotate during the operation of the blower fan 2. Further, below the noise detection microphone 6, a control speaker 8 as a control sound output device that outputs a control sound for noise is disposed so as to face the center of the air flow path from the wall of the housing.

Furthermore, a muffler effect detection microphone 9 is attached to the bottom wall of the air conditioner, for example, at the top of the outlet 5 as a muffler effect detecting device for detecting noise coming out of the outlet 5 and detecting the muffler effect. Yes. The silencing effect detection microphone 9 is attached in the direction opposite to the flow path. Note that the installation position of the muffler effect detection microphone 9 is not limited to the upper part of the air outlet 5, but may be an opening of the air outlet 5. For example, the muffler effect detection microphone 9 may be attached to the lower part or the side part of the air outlet 5. Further, the silencing effect detection microphone 9 does not need to be provided in the direction opposite to the flow path accurately. The muffler effect detection microphone 9 only needs to be provided toward the outside of the air conditioner 1 (housing). That is, the silencing effect detection microphone 9 may be installed at a position where noise radiated indoors can be detected.

Also, the output signals of the noise detection microphone 6 and the silencing effect detection microphone 9 are input to a signal processing device 10 which is a control sound generation device for generating a signal (control sound) for controlling the control speaker 8.

The silencing mechanism of the air conditioner 1 includes the noise detection microphone 6, the control speaker 8, the silencing effect detection microphone 9, and the signal processing device 10.

FIG. 5 shows a configuration diagram of the signal processing apparatus 10. The electric signal input from the noise detection microphone 6 is amplified by the microphone amplifier 11 and converted from an analog signal to a digital signal by the A / D converter 12. The electric signal input from the muffler effect detection microphone 9 is amplified by the microphone amplifier 11, converted from an analog signal to a digital signal by the A / D converter 12, and averaged by multiplying the weighting coefficient by the weighting means 13. . Each digital signal converted in this way is input to the FIR filter 18 and the LMS algorithm 19. The FIR filter 18 generates a control signal that is corrected so that the noise detected by the noise detection microphone 6 has the same amplitude and opposite phase as the noise when the noise detection effect detection microphone 9 is installed. . This control signal is converted from a digital signal to an analog signal by the D / A converter 14, amplified by the amplifier 15, and emitted from the control speaker 8 as a control sound.

<A-2. Operation>
Next, the operation of the air conditioner 1 will be described. When the air conditioner 1 operates, the impeller 25 of the blower fan 2 rotates, the indoor air is sucked in from the upper side of the blower fan 2, and the air is sent to the lower side of the blower fan 2 to generate an air flow. Along with this, an operation sound (noise) is generated in the vicinity of the air outlet of the blower fan 2, and the sound propagates downstream.

In the vicinity of the air outlet 5 of the blower fan 2, air current turbulence occurs due to the rotation of the impeller 25. Moreover, since the air blown from the blower fan 2 is blown outward from the blower outlet of the blower fan 2, the air hits the side wall of the casing of the air conditioner 1, and further air turbulence is caused. For this reason, on the side wall of the air conditioner 1, pressure fluctuation due to airflow turbulence increases. In contrast, in the region (cylindrical region A) inside the inner periphery of the blades of the blower fan 2, the turbulence of the airflow is small, and the pressure fluctuation due to the airflow is also small.

In order to support this, FIG. 6 shows the results of an experiment in which the airflow blown from the blower fan 2 was visualized. FIG. 6 is a photograph when the blower fan 2 is operated after the blower fan 2 is attached to the right end of the duct-shaped cylinder and white smoke is retained in the duct. When attention is paid to the vicinity of the air outlet of the blower fan 2, in the area excluding the vicinity of the stationary blade mounting member 7 and the cylindrical area A, the smoke staying white is thin, and the white smoke is being swept away by the airflow. I understand. On the other hand, white smoke remains in the vicinity of the stationary blade mounting member 7 of the blower fan 2 and the cylindrical region A, and the influence of the airflow is small. That is, it can be seen that the vicinity of the stationary blade mounting member 7 of the blower fan 2 and the columnar region A are not easily affected by the air current, and the pressure fluctuation due to the air current disturbance is small.

The air sent by the blower fan 2 passes through the air flow path and is sent to the heat exchanger 4. For example, in the case of cooling operation, the heat exchanger 4 is supplied with refrigerant from a pipe connected to an outdoor unit (not shown). The air sent to the heat exchanger 4 is cooled by the refrigerant flowing through the heat exchanger 4 to become cold air, and is directly discharged into the room from the outlet 5.

Next, a method for suppressing the operation sound of the air conditioner 1 will be described. The operation sound (noise) including the blowing sound of the blower fan 2 in the air conditioner 1 is detected by the noise detection microphone 6 attached to the stationary blade attachment member 7 of the blower fan 2. The noise detected by the noise detection microphone 6 becomes a digital signal via the microphone amplifier 11 and the A / D converter 12 and is input to the FIR filter 18 and the LMS algorithm 19.

The tap coefficient of the FIR filter 18 is updated sequentially by the LMS algorithm 19. In the LMS algorithm 19, the optimum tap coefficient is updated so that the error signal e approaches zero according to the equation 1 (h (n + 1) = h (n) + 2 · μ · e (n) · x (n)). .

Note that h is a filter tap coefficient, e is an error signal, x is a filter input signal, and μ is a step size parameter. The step size parameter μ controls the filter coefficient update amount for each sampling.

In this way, the digital signal having the tap coefficient updated by the LMS algorithm 19 and passing through the FIR filter 18 is converted into an analog signal by the D / A converter 14, amplified by the amplifier 15, and outputted as a control sound from the control speaker 8. It is discharged into the air flow path in the air conditioner 1.

On the other hand, to the muffler effect detection microphone 9 attached to the upper part of the air outlet 1 of the air conditioner 1 in the direction opposite to the flow path, it propagates from the blower fan 2 through the air flow path and is released into the room from the air outlet 5 The sound after the control sound emitted from the control speaker 8 interferes with the generated noise is detected. As described above, the signal detected by the mute effect detection microphone 9 is converted into a digital signal and averaged by the weighting means 13.

FIG. 7 is a diagram showing a circuit of weighting means in Embodiment 1 of the present invention.
The weighting unit 13 includes an integrator including a multiplier 21 that multiplies an input signal by a weighting coefficient, an adder 32, a delay element 33 for one sampling, and a multiplier 34.

In the first embodiment, the weighting coefficient of the multiplier 21 can be set from the outside depending on the installation environment or the like.
For example, in an environment where the disturbance is large and the operation is unstable, the weighting coefficient of the multiplier 21 may be set small. Conversely, in an environment where the disturbance is small, the weighting coefficient of the multiplier 21 may be set large. Thereby, the sensitivity with respect to an environmental change can be changed. Here, the averaging by the weighting means 13 may not be performed until the LMS algorithm 19 is stabilized. This is because the noise cannot be sufficiently reduced while the LMS algorithm 19 is not stable, and the output value of the weighting means 13 may run away. Furthermore, resetting may be performed when the output value of the weighting means 13 exceeds a certain value.

The signal averaged in this way is treated as the error signal e of the LMS algorithm 19 described above. Then, feedback control is performed so that the error signal e approaches zero, and the tap coefficient of the FIR filter 18 is appropriately updated. As a result, noise in the vicinity of the outlet 5 can be suppressed by the control sound that has passed through the FIR filter 18.

Since noise from the air conditioner 1 felt by humans is noise after being discharged into the room from the air outlet 5, the silencing effect detection microphone 9 is directed to the room on the opposite side of the flow path, so that The emitted noise can be detected. That is, by attaching the muffler effect detection microphone 9 to the upper part of the outlet 5 in the direction opposite to the flow path, it is possible to detect noise emitted into the room and sound with high coherence. Further, the muffler effect detection microphone 9 does not detect wind noise due to the air current because the air current is not directly applied. On the other hand, when the muffler effect detection microphone 9 is directed into the flow path, noise in the flow path is detected. For this reason, since the change of the characteristic of the sound in the place discharged | emitted from a blower outlet cannot be detected, the sound which the muffling effect detection microphone 9 detects differs from the noise in the room. Therefore, the coherence between the sound detected by the mute effect detection microphone 9 and the sound emitted into the room is reduced. Furthermore, since the airflow directly hits the silencing effect detection microphone 9, the silencing effect detection microphone 9 detects wind noise and further reduces the coherence.

Also, since the sound other than the noise generated from the blower fan 2 is included in the room, the stability of the feedback control is impaired by the sound other than the noise. For this reason, sounds other than noise are averaged by arranging the weighting means 13 in the preceding stage of the feedback control. Thereby, sound components other than uncorrelated noise can be canceled, and feedback control can be stably operated. That is, the coherence between the noise detection microphone 6 and the silencing effect detection microphone 9 can be increased.

And in this Embodiment 1, since the noise detection microphone 6 is attached to the stationary blade attachment member 7 of the ventilation fan 2, an airflow does not directly hit the noise detection microphone 6. FIG. For this reason, it can reduce that the noise detection microphone 6 detects the pressure fluctuation component by airflow disturbance. Therefore, the noise detection microphone 6 can detect noise that is an operation sound of the blower fan 2 and a sound having high coherence. In addition, since the muffler effect detection microphone 9 is attached to the upper part of the outlet 5 in the direction opposite to the flow path, the muffler effect detection microphone 9 is not directly exposed to the airflow, and the muffler effect detection microphone 9 is not affected by the airflow. . Furthermore, since the silencing effect detection microphone 9 can detect only the noise emitted into the room, the silencing effect detection microphone 9 can detect the noise actually heard by a person in the room and the noise having high coherence. it can. Further, since the sound detected by the muffling effect detection microphone 9 is averaged by the weighting means 13 and feedback control is performed, the sound detected by the muffler effect detection microphone 9 other than the noise from the air conditioner 1 is included. The components can be averaged and canceled. For this reason, high coherence is obtained for the detection sounds of the noise detection microphone 6 and the silencing effect detection microphone 9. For these reasons, there is a high coherence among the noise generated from the blower fan 2, the detection sound of the noise detection microphone 6, the detection sound of the mute effect detection microphone 9, and the indoor noise radiated from the air conditioner 1. Can be obtained, and a high silencing effect can be obtained.

An experimental result of measuring the coherence between the noise detection microphone 6 and the silencing effect detection microphone 9 when the noise detection microphone 6 is actually attached to the inner side of the inner periphery (cylindrical region A) of the blower fan 2 will be described.
FIG. 8 shows coherence characteristics between the detection sound of the noise detection microphone 6 and the detection sound of the mute effect detection microphone 9 when the noise detection microphone 6 is installed outside the cylindrical region A and the blower fan 2 is operated. . Next, FIG. 9 shows coherence characteristics between the detection sound of the noise detection microphone 6 and the detection sound of the mute effect detection microphone 9 when the blower fan 2 is operated by being installed inside the cylindrical region A.
Comparing FIG. 8 and FIG. 9, it can be seen that the coherence is clearly higher when the noise detection microphone 6 is installed inside the cylindrical region A.

Furthermore, by attaching the noise detection microphone 6 to the stationary blade attachment member 7 of the blower fan 2, the noise detection microphone 6 can be easily attached without newly increasing the number of parts, and a precise attachment mechanism becomes unnecessary. . Moreover, since the distance between the blower fan 2 and the noise detection microphone 6 can be shortened by installing the noise detection microphone 6 on the stationary blade mounting member 7 of the blower fan 2, the height of the air conditioner 1 is shortened. Can do.

In the first embodiment, the noise detection microphone 6 is installed on the stationary blade mounting member 7. However, inherent mechanical vibration accompanying rotation of the blower fan 2 is transmitted to the stationary blade mounting member 7, and the vibration is transmitted to the noise detection microphone 6. May be detected. In this case, the coherence between the noise detection microphone 6 and the silencing effect detection microphone 9 may be locally deteriorated. In such a case, the noise detection microphone 6 may be installed in a portion other than the stationary blade mounting member 7 in the cylindrical region A. For example, as shown in FIG. 10, the noise detection microphone 6 may be installed on the heat exchanger 4 in a range within the cylindrical region A. Further, for example, as shown in FIG. 11, the noise detection microphone 6 may be installed on the heat exchanger fixing bracket 30 in a range within the cylindrical region A. By installing the noise detection microphone 6 in this manner, the coherence between the noise detection microphone 6 and the silencing effect detection microphone 9 can be further increased as compared with the case where the noise detection microphone 6 is installed on the stationary blade mounting member 7. A higher silencing effect can be obtained.

In addition, the noise detection microphone 6 may be covered with a wall member 31 as shown in FIG. Since the air current can be blocked from the wall member, it is less affected by the air current, and a higher silencing effect can be obtained. In FIG. 12, the wall member 31 is formed in a substantially cylindrical shape, but the shape of the wall member 31 is arbitrary.
Even when the noise detection microphone 6 is attached to the heat exchanger 4 or the heat exchanger fixing bracket 30, the noise detection microphone 6 may be covered with the wall member 31. It is less affected by the airflow, and a higher silencing effect can be obtained.
Further, the muffler effect detection microphone 9 attached to the upper part of the air outlet 5 in the direction opposite to the flow path may be covered with a wall member. Since the airflow can be blocked, the sound deadening effect detecting microphone 9 is not affected by the airflow, and a higher sound deadening effect can be obtained.

In the first embodiment, an example of an axial fan as the blower fan 2 has been described as an example. However, any fan that blows air by rotating an impeller may be used.
In the first embodiment, the FIR filter 18 and the LMS algorithm 19 are used for the signal processing device 10. However, any adaptive signal processing circuit that can bring the sound detected by the mute effect detection microphone 9 close to zero can be used. A filtered-X algorithm generally used in the mute method may be used.
Further, the weighting means 13 does not need to be an integrator, and may be any means that can average.
Further, the signal processing device 10 does not need to be configured to perform adaptive signal processing, and may be configured to generate a control sound using a fixed tap coefficient.
Further, the signal processing device 10 does not need to be a digital signal processing circuit, and may be an analog signal processing circuit.

<A-3. Effect>
As described above, in the air conditioner 1 according to the first embodiment, the noise detection microphone 6 that is a noise detection device is provided in the cylindrical region A and on the stationary member of the blower fan 2. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. Moreover, since the noise detection microphone 6 can be installed without increasing the number of parts of the air conditioner 1 without changing the mechanism of the blower fan 2, the air conditioner 1 having a high degree of installation freedom can be realized.
The stationary member of the blower fan 2 is not limited to the stationary blade mounting member 7. If there is a stationary member in which at least a part of the components of the blower fan 2 is disposed in the cylindrical region A, the noise detection microphone 6 may be provided in a range that is in the cylindrical region A of the stationary member.

Further, in the air conditioner 1 according to the first embodiment, the noise detection microphone 6 that is a noise detection device is provided in the cylindrical region A and on the downstream side of the blower fan 2. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. Moreover, since the noise detection microphone 6 can be installed without increasing the number of parts of the air conditioner 1 without changing the mechanism of the blower fan 2, the air conditioner 1 having a high degree of installation freedom can be realized. Furthermore, since the inherent mechanical vibration associated with the rotation of the blower fan 2 is not detected by the noise detection microphone 6, the active noise reduction can be performed with higher accuracy than when the noise detection microphone 6 is provided on the stationary member of the blower fan 2. Can do.
When the noise detection microphone 6 is provided on the downstream side of the blower fan 2, the components for providing the noise detection microphone 6 are not limited to the heat exchanger 4 or the heat exchanger fixture 30. If there is a component that is at least partially in the cylindrical region A and disposed on the downstream side of the blower fan 2, the noise detection microphone 6 may be provided in a range that is in the cylindrical region A of the component.

Further, in the air conditioner 1 according to the first embodiment, the muffler effect detection microphone 9 which is a muffler effect detection device is provided at the opening of the air outlet 5 and is arranged toward the outside of the air conditioner 1. Yes. For this reason, the noise emitted into the room can be detected without being influenced by the airflow. Therefore, high coherence can be obtained for the indoor noise radiated from the air conditioner 1 and the detection sound of the muffler effect detection microphone 9. For this reason, it is possible to perform active silencing with high accuracy against the indoor noise radiated from the air conditioner 1.

In the air conditioner 1 according to the first embodiment, the signal processing device 10 that is the control sound generation device weights the detection result detected by the muffler effect detection microphone 9 that is the muffler effect detection device, A circuit for performing feedback control is provided. For this reason, it can cancel by averaging sounds other than the noise of the air conditioner 1 detected by the muffler effect detection microphone 9. Therefore, a high coherence sound can be detected between the noise detection microphone 6 and the silencing effect detection microphone 9, and active silencing with higher accuracy can be performed.

Further, in the air conditioner 1 according to the first embodiment, the noise detection microphone 6 is installed in a range in the cylindrical region A of the stationary blade mounting member 7 of the blower fan 2. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. Moreover, since the noise detection microphone 6 can be installed without increasing the number of parts of the air conditioner without changing the mechanism of the blower fan 2, the air conditioner 1 having a high degree of freedom in installation can be realized.

Further, in the air conditioner 1 according to the first embodiment, the noise detection microphone 6 is provided in a range that is in the cylindrical region A of the heat exchanger 4. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. Moreover, since the noise detection microphone 6 can be installed without increasing the number of parts of the air conditioner without changing the mechanism of the blower fan 2, the air conditioner 1 having a high degree of freedom in installation can be realized. Furthermore, since the inherent mechanical vibration associated with the rotation of the blower fan 2 is not detected by the noise detection microphone 6, the active noise reduction can be performed with higher accuracy than when the noise detection microphone 6 is provided on the stationary member of the blower fan 2. Can do.

Further, in the air conditioner 1 according to the first embodiment, the noise detection microphone 6 is provided in a range that is in the cylindrical region A of the heat exchanger fixture 30. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. Moreover, since the noise detection microphone 6 can be installed without increasing the number of parts of the air conditioner without changing the mechanism of the blower fan 2, the air conditioner 1 having a high degree of freedom in installation can be realized. Furthermore, since the inherent mechanical vibration associated with the rotation of the blower fan 2 is not detected by the noise detection microphone 6, the active noise reduction can be performed with higher accuracy than when the noise detection microphone 6 is provided on the stationary member of the blower fan 2. Can do.

Further, in the air conditioner 1 according to the first embodiment, the noise detection microphone 6 is covered with the wall member 31. By blocking the air flow, the noise detection microphone 6 is less affected by the air flow, so that a higher silencing effect can be obtained.

Further, in the air conditioner 1 according to the first embodiment, the silencing effect detection microphone 9 is covered with a wall member. By blocking the airflow, the muffler effect detection microphone 9 is not further affected by the airflow, so that a higher noise reduction effect can be obtained.

<B. Second Embodiment>
<B-1. Configuration>
In the second embodiment, an air conditioner in which a noise / muffling effect detection microphone 16 is arranged as a noise / muffling effect detection device that integrates the noise detection microphone 6 and the muffling effect detection microphone 9 in the first embodiment will be described. In the second embodiment, items that are not particularly described are the same as those in the first embodiment, and the same functions and configurations are described using the same reference numerals.

FIG. 13 is a cross-sectional view of the air conditioner 1 shown in FIG. 2 cut along a cross-section X, and is a diagram illustrating the configuration of the air conditioner 1 according to the second embodiment.

The air conditioner 1 in FIG. 13 constitutes an indoor unit. The air inlet 1 (more specifically, the casing of the air conditioner 1) has an inlet 3 at the top, and a blower 5 at the lower end. Each is open.

An air flow path is formed in the air conditioner 1 so as to communicate the suction port 3 and the blowout port 5. An axial flow fan having a substantially vertical rotation axis is provided below the suction port 3 of the air flow path. The provided blower fan 2 is provided. A heat exchanger 4 that cools or heats the air by exchanging heat is disposed below the blower fan 2. The heat exchanger 4 is fixed in the housing by a heat exchanger fixing bracket 30. As shown by the white arrow in FIG. 13, when the blower fan 2 is activated, the indoor air is sucked into the air flow path in the air conditioner 1 from the suction port 3, and this intake air is in the lower part of the blower fan 2. After cooling or heating with the heat exchanger 4, the air is blown out into the room from the outlet 5.

The air conditioner 1 described in the first embodiment is different from the air conditioner 1 described in the first embodiment in that the air conditioner 1 described in the first embodiment includes two microphones, a noise detection microphone 6 and a silencing effect detection microphone 9 for active silencing. However, in the air conditioner 1 of the second embodiment, these are replaced with the noise / silencing effect detection microphone 16 which is a single microphone. . Further, since the signal processing method is different, the contents of the signal processing device 17 are different.

A control speaker 8 that outputs a control sound for noise is arranged on the side wall portion of the casing of the air conditioner 1 so as to face the center of the air flow path from the wall. In addition, the control sound emitted from the control speaker 8 is caused to interfere with the operation sound (noise) of the air conditioner 1 including the blowing sound of the blower fan 2 in the range within the cylindrical region A of the stationary blade mounting member 7. A noise / muffling effect detection microphone 16 for detecting the sound after the sound is disposed. The stationary blade attaching member 7 is independent of the rotating impeller during operation of the blower fan 2 and is configured not to rotate. For this reason, the noise / muffling effect detection microphone 16 also does not rotate during the operation of the blower fan 2.

The output signal of the noise / muffling effect detection microphone 16 is input to a signal processing device 17 which is a control sound generating device for generating a signal (control sound) for controlling the control speaker 8.

The silencer mechanism of the air conditioner 1 includes the noise / silencer effect detection microphone 16, the control speaker 8, and the signal processing device 17.

FIG. 14 shows a configuration diagram of the signal processing device 17. The electric signal converted from the sound signal by the noise / muffling effect detection microphone 16 is amplified by the microphone amplifier 11 and converted from an analog signal to a digital signal by the A / D converter 12. The converted digital signal is input to the LMS algorithm 19. Further, a difference signal from the signal obtained by convolving the FIR filter 20 with the output signal of the FIR filter 18 is input to the FIR filter 18 and the LMS algorithm 19. Next, the difference signal is subjected to a convolution operation by the tap coefficient calculated by the LMS algorithm 19 in the FIR filter 18, then converted from a digital signal to an analog signal by the D / A converter 14, and amplified by the amplifier 15. , And emitted as a control sound from the control speaker 8.

<B-2. Operation>
Next, the operation of the air conditioner 1 will be described. When the air conditioner 1 operates, the impeller 25 of the blower fan 2 rotates, the indoor air is sucked in from the upper side of the blower fan 2, and the air is sent to the lower side of the blower fan 2 to generate an air flow. Along with this, an operation sound (noise) is generated in the vicinity of the air outlet of the blower fan 2, and the sound propagates downstream.

In the vicinity of the air outlet of the blower fan 2, air current disturbance is caused by the rotation of the impeller 25 as in the first embodiment. Moreover, since the air blown out from the blower fan 2 is blown outward from the blower outlet of the blower fan 2, it collides with the side wall of the casing of the air conditioner 1 and further air turbulence is caused. For this reason, pressure fluctuations due to airflow turbulence increase on the side wall of the air conditioner 1. In contrast, in the region (cylindrical region A) inside the blade inner periphery of the blower fan 2, the turbulence of the airflow is small, and the pressure fluctuation due to the airflow is also small.

Next, a method for suppressing the operation sound of the air conditioner 1 will be described. The sound after the control sound output from the control speaker 8 interferes with the operation sound (noise) including the blowing sound of the blower fan 2 is detected as noise / noise reduction effect attached to the stationary blade mounting member 7 of the blower fan 2. It is detected by the microphone 16. The noise detected by the noise / muffling effect detection microphone 16 becomes a digital signal via the microphone amplifier 11 and the A / D converter 12.

In order to perform the same suppression method as the operation sound suppression method described in the first embodiment, it is necessary to input noise to be silenced to the FIR filter 18. Further, as shown in Expression 1, it is necessary to input the sound after the noise to be silenced as the input signal and the control sound as the error signal are interfered to the LMS algorithm 19. However, since the noise / muffling effect detection microphone 16 can only detect the sound after the control sound has interfered, it is necessary to create noise to be muffled from the sound detected by the noise / muffling effect detection microphone 16.

FIG. 15 shows the waveform of the sound after interference between the noise and the control sound (a in FIG. 15), the waveform of the control sound (b in FIG. 15), and the waveform of the noise (c in FIG. 15). Is. From the principle of sound superposition, b + c = a. Therefore, in order to obtain c from a, the difference between a and b may be taken. That is, the noise to be silenced can be created from the difference between the interference sound detected by the noise / silence effect detection microphone 16 and the control sound.

FIG. 16 shows a route from the control signal output from the FIR filter 18 as a control sound output from the control speaker 8 to the noise / muffling effect detection microphone 16 and input to the signal processing device 17. FIG. It passes through the D / A converter 14, the amplifier 15, the path from the control speaker 8 to the noise / silence effect detection microphone 16, the noise / silence effect detection microphone 16, the microphone amplifier 11, and the A / D converter 12.

Suppose that the transfer characteristic of this path is H, the FIR filter 20 in FIG. 14 estimates the transfer characteristic H. By convolving the FIR filter 20 with the output signal of the FIR filter 18, the control sound can be estimated as the signal b detected by the noise / silence effect detection microphone 16, and after the interference detected by the noise / silence effect detection microphone 16 The noise c to be silenced is generated by taking the difference from the sound a.

The noise c to be silenced generated in this way is supplied to the LMS algorithm 19 and the FIR filter 18 as an input signal. The digital signal that has passed through the FIR filter 18 whose tap coefficient has been updated by the LMS algorithm 19 is converted to an analog signal by the D / A converter 14, amplified by the amplifier 15, and then supplied from the control speaker 8 as a control sound to the air conditioner. 1 is discharged into the air flow path in the body.

On the other hand, the noise / silencing effect detection microphone 16 attached to the stationary blade attachment member 7 of the blower fan 2 is the sound after the control sound emitted from the control speaker 8 interferes with the noise generated from the blower fan 2. Is detected. Since the error signal of the LMS algorithm 19 described above is input with the sound detected by the noise / muffling effect detection microphone 16, the tap coefficient of the FIR filter 18 is updated so that the sound after the interference approaches zero. Will be. As a result, noise generated from the blower fan 2 can be suppressed by the control sound that has passed through the FIR filter 18.

As described above, in the second embodiment, in the air conditioner 1 to which the active silencing method is applied, the noise / silencing effect detection microphone 16 is mounted in a range within the cylindrical region A of the stationary blade mounting member 7. It is possible to reduce the detection of the pressure fluctuation component due to the turbulence of the air flow without direct contact with the air flow. For this reason, the noise which is the driving | running sound of the ventilation fan 2, and a sound with high coherence can be detected, and a high silencing effect can be acquired.

Furthermore, by attaching the noise / silencing effect detecting microphone 16 to the stationary blade mounting member 7 of the blower fan 2, the noise / silencing effect detecting microphone 16 can be easily attached without increasing the number of parts. No mounting mechanism is required. Moreover, since the noise / silence effect detection microphone 16 is installed on the stationary blade mounting member 7 of the blower fan 2, the distance between the blower fan 2 and the noise / silence effect detection microphone 16 can be shortened. The height can be shortened.

In the second embodiment, the noise / silencing effect detection microphone 16 is installed on the stationary blade mounting member 7, but the inherent mechanical vibration accompanying the rotation of the blower fan 2 is transmitted to the noise / silence effect detection microphone 16. The noise detection microphone 6 may detect the vibration. For this reason, the silencing effect may be reduced. In such a case, the noise / muffling effect detection microphone 16 may be installed in a portion other than the stationary blade mounting member 7 in the cylindrical region A. For example, as shown in FIG. 17, the noise detection microphone 6 may be installed on the heat exchanger 4 in the range within the cylindrical region A. Further, for example, as shown in FIG. 18, a noise / silencing effect detection microphone 16 may be installed on the heat exchanger fixing bracket 30 in a range within the cylindrical region A. By installing the noise / silencing effect detection microphone 16 in this way, a higher silencing effect can be obtained than when the noise / silencing effect detection microphone 16 is installed on the stationary blade mounting member 7.

Further, as shown in FIG. 19, the noise / muffling effect detection microphone 16 may be covered with a wall member 31. Since the air current can be blocked from the wall member, it is less affected by the air current, and a higher silencing effect can be obtained. In FIG. 19, the wall member 31 is formed in a substantially cylindrical shape, but the shape of the wall member 31 is arbitrary.
Further, even when the noise / silencing effect detection microphone 16 is attached to the heat exchanger 4 or the heat exchanger fixing bracket 30, the noise / silence effect detection microphone 16 may be covered with the wall member 31. It is less affected by the airflow, and a higher silencing effect can be obtained.
In the second embodiment, the axial fan is used as the blower fan 2 as an example. However, any fan that blows air by rotating the impeller may be used.

In the second embodiment, the FIR filter 18 and the LMS algorithm 19 are used as the adaptive signal processing circuit. However, any adaptive signal processing circuit may be used as long as the sound detected by the noise / muffling effect detection microphone 16 approaches zero.
Further, the signal processing device 17 does not need to be configured to perform adaptive signal processing, and may be configured to generate control sound using a fixed tap coefficient.
Further, the signal processing device 17 does not need to be a digital signal processing circuit, and may be an analog signal processing circuit.

<B-3. Effect>
As described above, in the air conditioner 1 according to the second embodiment, the noise / silence effect detection microphone 16 that is the noise / silence effect detection device is provided in the cylindrical region A and on the stationary member of the blower fan 2. Yes. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. In addition, since the noise / muffling effect detection microphone 16 can be installed without increasing the number of parts of the air conditioner 1, the air conditioner 1 having a high degree of installation freedom can be realized.

In the air conditioner 1 according to the second embodiment, the noise / silence effect detection microphone 16 that is a noise / silence effect detection device is provided in the cylindrical region A and downstream of the blower fan 2. Yes. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. Further, since the noise / silence effect detection microphone 16 can be installed without increasing the number of parts of the air conditioner 1 without changing the mechanism of the blower fan 2, the air conditioner 1 having a high degree of installation freedom can be realized. . Further, since the inherent mechanical vibration associated with the rotation of the blower fan 2 is not detected by the noise / silencing effect detection microphone 16, the noise / silencing effect detection microphone 16 is more accurate than the case where the noise / silence effect detection microphone 16 is provided on the stationary member of the blower fan 2. High active silencing can be performed.

Further, in the air conditioner 1 according to the second embodiment, the noise / silencing effect detection microphone 16 is installed in a range that is in the cylindrical region A of the stationary blade mounting member 7 of the blower fan 2. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. In addition, since the noise / silencing effect detection microphone 16 can be installed without changing the mechanism of the blower fan 2 and without increasing the number of parts of the air conditioner, the air conditioner 1 having a high degree of freedom in installation can be realized.

Further, in the air conditioner 1 according to the second embodiment, the noise / muffling effect detection microphone 16 is provided in a range in the cylindrical region A of the heat exchanger 4. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. In addition, since the noise / silencing effect detection microphone 16 can be installed without changing the mechanism of the blower fan 2 and without increasing the number of parts of the air conditioner, the air conditioner 1 having a high degree of freedom in installation can be realized. Further, since the inherent mechanical vibration associated with the rotation of the blower fan 2 is not detected by the noise / silencing effect detection microphone 16, the noise / silencing effect detection microphone 16 is more accurate than the case where the noise / silence effect detection microphone 16 is provided on the stationary member of the blower fan 2. High active silencing can be performed.

Further, in the air conditioner 1 according to the second embodiment, the noise / muffling effect detection microphone 16 is provided in a range within the cylindrical region A of the heat exchanger fixing bracket 30. For this reason, since the influence of the airflow from the blower outlet of the blower fan 2 can be reduced and a sound with high noise and coherence can be detected, high-accuracy active silencing can be performed. In addition, since the noise / silencing effect detection microphone 16 can be installed without changing the mechanism of the blower fan 2 and without increasing the number of parts of the air conditioner, the air conditioner 1 having a high degree of freedom in installation can be realized. Further, since the inherent mechanical vibration associated with the rotation of the blower fan 2 is not detected by the noise / silencing effect detection microphone 16, the noise / silencing effect detection microphone 16 is more accurate than the case where the noise / silence effect detection microphone 16 is provided on the stationary member of the blower fan 2. High active silencing can be performed.

In the air conditioner 1 according to the second embodiment, the noise / muffling effect detection microphone 16 is covered with the wall member 31. By blocking the airflow, the noise / silencing effect detection microphone 16 is less affected by the airflow, so that a higher silencing effect can be obtained.

<C. Embodiment 3>
<C-1. Configuration>
In the third embodiment, a description will be given of an air conditioner in which a noise / silencing effect detection microphone 16 is installed at the upper part of the air outlet 5 so as to face the side opposite to the flow path. In Embodiment 3, items that are not particularly described are the same as those in Embodiment 1 or Embodiment 2, and the same functions and configurations are described using the same reference numerals.

FIG. 20 is a cross-sectional view when the front view of the air conditioner 1 shown in FIG. 2 is cut along a cross section X, and is a diagram showing a configuration of the air conditioner 1 according to the third embodiment.

The air conditioner 1 in FIG. 20 constitutes an indoor unit. The air inlet 1 (more specifically, the casing of the air conditioner 1) has an inlet 3 at the top, and a blower 5 at the lower end. Each is open.

An air flow path is formed in the air conditioner 1 so as to communicate the suction port 3 and the blowout port 5. An axial flow fan having a substantially vertical rotation axis is provided below the suction port 3 of the air flow path. The provided blower fan 2 is provided. A heat exchanger 4 that cools or heats the air by exchanging heat is disposed below the blower fan 2. The heat exchanger 4 is fixed in the housing by a heat exchanger fixing bracket 30. As shown by the white arrow in FIG. 20, when the blower fan 2 is activated, indoor air is sucked into the air flow path in the air conditioner 1 from the suction port 3, and this intake air is present at the lower part of the blower fan 2. After cooling or heating with the heat exchanger 4, the air is blown out into the room from the outlet 5.

A different point from the air conditioner 1 described in the second embodiment is that a noise / muffling effect detection microphone is arranged at the upper part of the air outlet 5 so as to face the side opposite to the flow path. Accordingly, the configuration of the signal processing device 22 is also different.

Even when the noise / muffling effect detection microphone 16 is attached to the upper part of the air outlet 5 in the direction opposite to the flow path, the noise / muffling effect detection microphone 16 is newly added without increasing the number of parts as in the second embodiment. It can be easily installed, eliminating the need for a precise mounting mechanism.

A control speaker 8 that outputs a control sound for noise is arranged on the side wall portion of the casing of the air conditioner 1 so as to face the center of the air flow path from the wall. In addition, a noise / silencing effect detection microphone 16 that detects sound after the control sound emitted from the control speaker 8 interferes with the operation sound (noise) of the air conditioner 1 including the sound of the blower fan 2 is provided. It arrange | positions so that it may face the other side of a flow path at the upper part of the blower outlet 5. FIG.

The output signal of the noise / muffling effect detection microphone 16 is input to a signal processing device 22 which is a control sound generation device for generating a signal (control sound) for controlling the control speaker 8.

FIG. 21 shows a configuration diagram of the signal processing device 22. The difference from the signal processing device 17 shown in FIG. 14 is that weighting means 13 is arranged between the output of the A / D converter 12 and the input of the LMS algorithm 19. Other configurations are the same as those of the signal processing device 17 of the second embodiment.

<C-2. Operation>
Next, the operation of the air conditioner 1 will be described. When the air conditioner 1 operates, the impeller 25 of the blower fan 2 rotates, the indoor air is sucked in from the upper side of the blower fan 2, and the air is sent to the lower side of the blower fan 2 to generate an air flow. Along with this, an operation sound (noise) is generated in the vicinity of the air outlet of the blower fan 2, and the sound propagates downstream.

In the vicinity of the air outlet of the blower fan 2, air current disturbance is caused by the rotation of the impeller 25 as in the first embodiment. Moreover, since the air blown out from the blower fan 2 is blown outward from the blower outlet of the blower fan 2, it collides with the side wall of the casing of the air conditioner 1 and further air turbulence is caused. For this reason, pressure fluctuations due to airflow turbulence increase on the side wall of the air conditioner 1.

However, in the third embodiment, the noise / silence effect detection microphone 16 is disposed above the air outlet 5 in the direction opposite to the flow path. The vicinity of the blower outlet 5 has a sufficiently large distance from the blower outlet of the blower fan 2 where the turbulence of airflow is large compared to the vicinity of the blower fan 2. Furthermore, in the vicinity of the air outlet 5, the air turbulence is rectified to some extent by the heat exchanger 4. For this reason, the turbulence of the airflow in the vicinity of the noise / silencing effect detection microphone 16 is reduced. Further, since the airflow is not directly applied to the area where the noise / silence effect detection microphone 16 is provided, the noise / silence effect detection microphone 16 is hardly affected by the airflow turbulence. Furthermore, since the noise from the air conditioner 1 felt by the person is the noise after being discharged from the air outlet 5 into the room, the noise / silencing effect detection microphone 16 is directed to the room on the opposite side of the flow path. Thus, noise emitted into the room can be detected.
That is, by attaching the noise / muffling effect detection microphone 16 to the upper part of the air outlet 5 in the direction opposite to the flow path, it is possible to detect noise emitted into the room and sound with high coherence.

Next, a method for suppressing the operation sound of the air conditioner 1 will be described. The control sound generation method of the third embodiment is the same as the method described in the second embodiment. The control sound generation method of the third embodiment is different from the method described in the second embodiment in that the weighting means 13 averages the signal input as an error signal to the LMS algorithm 19. .

When the noise / muffling effect detection microphone 16 is arranged on the upper side of the air outlet 5 in the direction opposite to the flow path, the noise detected by the noise / muffling effect detection microphone 16 is a sound other than the noise generated from the blower fan 2. Is probably included. For this reason, the stability of feedback control is impaired by sounds other than these noises. Therefore, in Embodiment 3, sounds other than noise are averaged by placing weighting means 13 in the previous stage of feedback control. Thereby, sound components other than uncorrelated noise can be canceled, and feedback control can be stably operated. That is, it is possible to increase the coherence between the noise after being discharged from the blow-out port 5 into the room and the noise / silencing effect detection microphone 16.

Note that, similarly to the first embodiment, averaging by the weighting means 13 may not be performed until the LMS algorithm 19 is stabilized. This is because the noise cannot be sufficiently reduced while the LMS algorithm 19 is not stable, and the output value of the weighting means 13 may run away. Furthermore, resetting may be performed when the output value of the weighting means 13 exceeds a certain value.

Further, the noise / muffling effect detection microphone 16 may be covered with a wall member 31 so as not to be further affected by the airflow. Since the air current can be blocked from the wall member, it is less affected by the air current, and a higher silencing effect can be obtained.
In the third embodiment, the axial fan is used as the blower fan 2 as an example. However, any fan that blows air by rotating the impeller may be used.
Further, the installation position of the noise / muffling effect detection microphone 16 is not limited to the upper part of the air outlet 5, but may be an opening of the air outlet 5. For example, the noise / muffling effect detection microphone 16 may be attached to the lower part or the side part of the air outlet 5. Further, the noise / muffling effect detection microphone 16 does not need to be provided in the direction opposite to the flow path accurately. The noise / muffling effect detection microphone 16 only needs to be provided toward the outside of the air conditioner 1 (housing). That is, the noise / muffling effect detection microphone 16 may be installed at a position where noise radiated indoors can be detected.

In the first embodiment, the FIR filter 18 and the LMS algorithm 19 are used for the signal processing device 22. However, any adaptive signal processing circuit may be used as long as the sound detected by the noise / muffling effect detection microphone 16 approaches zero. A filtered-X algorithm generally used in the active silencing method may be used.
Further, the weighting means 13 does not need to be an integrator, and may be any means that can average.
Further, the signal processing device 22 does not need to be configured to perform adaptive signal processing, and may be configured to generate control sound using a fixed tap coefficient.
Further, the signal processing device 22 does not have to be a digital signal processing circuit, and may be an analog signal processing circuit.

<C-3. Effect>
As described above, in the air conditioner 1 according to the third embodiment, the noise / silence effect detection microphone 16 that is a noise / silence effect detection device is provided at the opening of the air outlet 5 and is directed to the outside of the air conditioner 1. Arranged. For this reason, the noise emitted into the room can be detected without being influenced by the airflow. Therefore, high coherence can be obtained for the indoor noise radiated from the air conditioner 1 and the detection sound of the noise / silencing effect detection microphone 16. For this reason, it is possible to perform active silencing with high accuracy against the indoor noise radiated from the air conditioner 1.

Further, in the air conditioner 1 according to the third embodiment, the signal processing device 22 that is the control sound generation device uses the detection result detected by the noise / silence effect detection microphone 16 that is the noise / silence effect detection device. A circuit that performs weighting and performs feedback control is provided. For this reason, it can cancel by averaging sounds other than the noise of the air conditioner 1 detected by the noise / silencing effect detection microphone 16. Therefore, it is possible to perform active silencing with higher accuracy.

In the air conditioner 1 according to the third embodiment, the noise / muffling effect detection microphone 16 is covered with the wall member 31. By blocking the airflow, the noise / silencing effect detection microphone 16 is less affected by the airflow, so that a higher silencing effect can be obtained.

1. Air conditioner, 2. Air blower fan, 3. Air inlet, 4. Heat exchanger, 5. Air outlet, 6. Noise detection microphone, 7. Stator blade mounting member, 8. Control speaker, 9. Silencer effect detection microphone, 10, 17, 22. Signal processing. Equipment, 11 microphone amplifier, 12 A / D converter, 13 weighting means, 14 D / A converter, 15 amplifier, 16 noise / silence detection microphone, 18, 20 FIR filter, 19 LMS algorithm, 21 multiplier, 25 Impeller, 26 stationary blades, 27 boss, 28 rotating shaft, 30 heat exchanger fixture, 31 wall member, 32 adder, 33 delay element, 34 multiplier.

Claims

A housing in which an inlet and an outlet are formed;
A blower fan having an impeller;
A heat exchanger,
A noise detection device for detecting noise generated from the blower fan;
A control sound output device for outputting a control sound for reducing the noise;
A mute effect detecting device for detecting a mute effect of the control sound;
A control sound generation device that generates the control sound based on detection results of the noise detection device and the muffler effect detection device;
In an air conditioner comprising:
The noise detector is
An inscribed circle that is in contact with the inner peripheral portion of the impeller blade is disposed in a cylindrical region that extends in the direction of the rotation axis of the impeller, and is provided on the stationary member of the blower fan or on the downstream side of the blower fan. An air conditioner characterized by
The silencing effect detecting device is
2. The air conditioner according to claim 1, wherein the air conditioner is provided at an opening of the air outlet and disposed toward the outside of the housing.
The control sound generator is
The air conditioner according to claim 1 or 2, further comprising a circuit that performs feedback control by weighting a detection result detected by the muffler effect detection device.
The blower fan includes a stationary blade on the downstream side of the impeller,
The stationary blade is provided on a stationary blade mounting member at least partially disposed in the cylindrical region,
The air conditioner according to any one of claims 1 to 3, wherein the noise detection device is provided in a range to be the cylindrical region of the stationary blade mounting member.
The heat exchanger is provided on the downstream side of the blower fan so that at least a part of the heat exchanger is disposed in the cylindrical region,
The air conditioner according to any one of claims 1 to 3, wherein the noise detection device is provided in a range to be the cylindrical region of the heat exchanger.
The heat exchanger is provided on the downstream side of the blower fan,
The heat exchanger is fixed to the housing by a metal fitting at least partially disposed in the cylindrical region,
The air conditioner according to any one of claims 1 to 3, wherein the noise detection device is provided in a range to be the cylindrical region of the metal fitting.
The air conditioner according to any one of claims 1 to 6, wherein the noise detection device is covered with a wall member.
The air conditioner according to any one of claims 1 to 7, wherein the silencer detection device is covered with a wall member.
A housing in which an inlet and an outlet are formed;
A blower fan having an impeller;
A heat exchanger,
A control sound output device for outputting a control sound for reducing noise generated from the blower fan;
A noise / muffling effect detection device for detecting the noise and detecting a silencing effect of the control sound;
A control sound generation device that generates the control sound based on the detection result of the noise / silence effect detection device;
In an air conditioner comprising:
The noise / muffling effect detection device is:
An inscribed circle that is in contact with the inner peripheral portion of the impeller blade is disposed in a cylindrical region that extends in the direction of the rotation axis of the impeller, and is provided on the stationary member of the blower fan or on the downstream side of the blower fan. An air conditioner characterized by
The blower fan includes a stationary blade on the downstream side of the impeller,
The stationary blade is provided on a stationary blade mounting member at least partially disposed in the cylindrical region,
10. The air conditioner according to claim 9, wherein the noise / muffling effect detection device is provided in a range to be the cylindrical region of the stationary blade mounting member.
The heat exchanger is provided on the downstream side of the blower fan so that at least a part of the heat exchanger is disposed in the cylindrical region,
The air conditioner according to claim 9, wherein the noise / noise reduction effect detection device is provided in a range that becomes the cylindrical region of the heat exchanger.
The heat exchanger is provided on the downstream side of the blower fan,
The heat exchanger is fixed to the housing by a metal fitting at least partially disposed in the cylindrical region,
10. The air conditioner according to claim 9, wherein the noise / noise reduction effect detection device is provided in a range to be the cylindrical region of the metal fitting.
A housing in which an inlet and an outlet are formed;
A blower fan having an impeller;
A heat exchanger,
A control sound output device for outputting a control sound for reducing noise generated from the blower fan;
A noise / muffling effect detection device for detecting the noise and detecting a silencing effect of the control sound;
A control sound generation device that generates the control sound based on the detection result of the noise / silence effect detection device;
In an air conditioner comprising:
The noise / muffling effect detection device is:
An air conditioner provided at an opening of the air outlet and disposed toward the outside of the housing.
The control sound generator is
The air conditioner according to claim 13, further comprising a circuit that performs feedback control by weighting a detection result detected by the noise / noise reduction effect detection device.
The air conditioner according to any one of claims 9 to 14, wherein the noise / noise reduction effect detection device is covered with a wall member.