JPH10197034A - Muffler of air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To layout efficiently the detecting means of noise signals and the detecting means of silencing signals by arranging the detecting means of the noise signals inside the noise generation part of an indoor unit main body, a silencing speaker and the means of detecting the silencing signals from the silencing speaker on both sides of the indoor unit main body. SOLUTION: A noise detecting microphone (noise microphone) 2 is arranged near the noise source 1 and a silencing microphone 4 is arrange near the silencing speaker 3. The noise detecting microphone 2 is built into the noise generating part of the indoor unit main body and the silencing speaker 3 and the silencing microphone 4 are arranged on both sides of the indoor unit main body unifying them. Both of the silencing speaker 3 and silencing microphone 4 are arranged to the noise generating part of the indoor unit main body and the noise microphone 2 is arranged to the under part of the noise generating part of the indoor unit main body being built in. Therefore, the design can be neat and the installation work of it can be easier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for a blower fan of an air conditioner or a refrigerator.

[0002]

2. Description of the Related Art As a muffler for an air conditioner (air conditioner), a muffler chamber, a sound absorbing duct, etc. are provided in various places of an air conditioner duct system in order to prevent air conditioner noise in a theater or a conference room where a quiet indoor environment is required. There is a passive silencer. However, these passive silencers have been desired to be improved in terms of volume reduction in low frequency range, pressure loss, generation of air flow noise, installation space, and the like.

Therefore, as a new means for solving these problems, there is an active noise controller which emits an additional sound having the same amplitude and opposite phase to noise and reduces the noise by the interference effect of sound waves.

FIG. 8 shows a typical example of these. In FIG. 8, reference numeral 21 denotes an air conditioning duct connected to a discharge port of the conditioned air, from which the conditioned air is delivered. 22
Is a microphone that detects noise generated from the sound source, and 23 is a speaker that generates a control sound, and outputs a sound for canceling the uttered sound from the sound source. Reference numeral 24 denotes a noise-reduction microphone for detecting an error, 25 denotes a signal divider for a noise signal detected by the microphone 22, 26 denotes a digital adaptive filter (DAF) that processes the noise signal to generate a signal for generating a control sound, and 27 denotes a signal. A transfer filter for superimposing a transfer function characteristic between the muffling speaker 23 and the muffling microphone 24 on the output of the noise signal of the signal divider; a digital adaptive filter 26 based on the output of the transfer function filter 27 and the signal from the muffling microphone 24; Is a least-squares calculation unit (LMS) that adjusts the coefficient of.

[0005] The detection outputs of the microphones 22 and 24 are a low-pass filter and an analog-digital (A / D).
After being converted and processed, the output to the speaker is performed through a low-pass filter after digital-to-analog (D / A) conversion of the digital output from the DAF.

The basic operation of the muffler having such a configuration is based on the information of the input (signal from the microphone 22 for noise detection) x of the digital adaptive filter 26 and the output (error signal) e of the muffling microphone 24. The coefficient of the digital adaptive filter 26 is converted to a least squares operation unit (LM) by adaptive control so that the energy is minimized.
S) It is obtained in step 28 and updated successively.

When the above method is installed in an air conditioner,
In an air conditioner using a duct, the distance between the noise source and the muffling microphone is relatively large, so even if the coefficients of the digital adaptive filter are obtained by the least-squares calculation unit (LMS) and sequentially updated, it is possible in time. However, in a separation type air conditioner that does not use a duct, the distance corresponding to the duct is as short as about 10 cm, and muffling must be performed within this distance. Moreover, it is necessary to determine the coefficients of the digital adaptive filter by the least squares calculation unit (LMS) almost in real time. Therefore, a digital signal processor (DSP) capable of high-speed parallel processing compared to a microcomputer
However, since a single unit has a limited processing capability, a plurality of DSPs are required.

As another example, as an input signal, only the error signal of the noise reduction microphone is used as an input signal, and a signal obtained by compensating howling characteristics from the noise reduction speaker to the noise reduction microphone is used as a reference signal to calculate the coefficient of the adaptive filter,
In some cases, feedback control is performed by using a least square calculation unit (LMS). However, even with this type of silencer, the A / D converter, D / A converter,
Delay time occurs in the processing time of digital signal processing devices, etc.
An optimum filter coefficient could not be obtained, and noise could not be silenced for random noise.

[0009]

SUMMARY OF THE INVENTION In such a silencer mounted on an indoor unit of a unit type air conditioner, the indoor unit is made compact, and the detection of noise signals and the generation of silence signals are effectively performed. Therefore, the present invention provides a noise reduction device for an air conditioner in which a means for detecting the noise signal, a noise reduction speaker, and a means for detecting a noise reduction signal of the noise reduction speaker are effectively arranged. The purpose is to do so.

[0010]

According to a first aspect of the present invention, there is provided a muffler for an air conditioner, comprising at least a blower fan and a suction port and a discharge port for circulating air in a room to be conditioned by using the blower fan. An air conditioner having a means for detecting a noise signal of a noise source such as a blower fan of an indoor unit, a filter to which the noise signal is input, and a muffling speaker to which an output signal of this filter is applied, The filter has a plurality of filter constants calculated so that the noise signal and the muffling signal have opposite phases for each range of the number of revolutions of the blower fan. However, the air conditioner is designed to select a filter constant corresponding to the current fan rotation speed or a filter having a constant corresponding to the fan rotation speed. This is achieved by incorporating the means for detecting the noise signal in the noise generating portion of the indoor unit main body, and arranging the muffling speaker and the means for detecting the muffling signal of the muffling speaker on both sides of the indoor unit main body. .

In this way, the noise microphone is built in the noise generating portion of the indoor unit main body, and the sound deadening speaker and the sound deadening microphone are arranged on both sides of the indoor unit main body. It can be gathered up on both sides of the indoor unit without taking up space.

According to a second aspect of the present invention, there is provided a noise reduction device for an air conditioner having at least a blower fan and a suction port and a discharge port for circulating air in a conditioned room using the blower fan. Means for detecting a noise signal of a noise source such as a blower fan of an indoor unit, a filter to which a noise signal is input, a muffling speaker to which an output signal of the filter is applied, and a muffling signal of a muffling speaker. The filter has a plurality of filter constants calculated so that the noise signal and the muffling signal detected for each range of the rotation speed of the blower fan are in opposite phases. An air conditioner in which a filter constant corresponding to a fan rotation speed is selected or a filter having a constant corresponding to a fan rotation speed is selected. Means for detecting a built-in noise generation point of the indoor unit main body, is achieved by incorporating placed and means for detecting a mute signal of the mute speaker and the silencing speaker on each side of the indoor unit body.

Thus, the noise microphone is built in the noise generating portion of the indoor unit main body, and the muffling speaker and the muffling microphone are arranged on both sides of the indoor unit main body. The built-in and integrated structure makes the design cleaner and the installation work easier.

According to a third aspect of the present invention, there is provided an air conditioner silencer having at least a blower fan and a suction port and a discharge port for circulating air in a conditioned room using the blower fan. Means for detecting a noise signal of a noise source such as a blower fan of an indoor unit, a plurality of filters to which the noise signal is input, a muffling speaker to which an output signal of the filter is applied, and muffling of a muffling speaker Signal detecting means, the plurality of filters have a plurality of filter constants calculated so that the noise signal and the muffling signal detected for each range of the rotation speed of the blower fan are in opposite phases, In an air conditioner in which a filter constant corresponding to the current fan rotation speed is selected or a filter having a constant corresponding to the fan rotation speed is selected. The means for detecting the noise signal is built in a noise generating portion of the indoor unit main body, and the muffling speaker and the means for detecting the muffling signal of the muffling speaker are provided at positions corresponding to the vertical noise generating portion of the indoor unit main body. This is achieved by positioning.

In this manner, the noise microphone is built in the noise generating portion of the indoor unit main body, and the silencing speaker and the noise reducing microphone are arranged at the positions corresponding to the vertical noise generating portion of the indoor unit main body, whereby the air conditioner of the air conditioner is provided. Even in a place where the space in the lateral direction is not enough, it can be installed without deteriorating the silencing effect.

According to a fourth aspect of the present invention, there is provided an air conditioner muffler having at least a blower fan and a suction port and a discharge port for circulating air in a conditioned room using the blower fan. Means for detecting a noise signal of a noise source such as a blower fan of an indoor unit, a plurality of filters to which the noise signal is input, a muffling speaker to which an output signal of the filter is applied, and muffling of a muffling speaker Signal detecting means, the plurality of filters have a plurality of filter constants calculated so that the noise signal and the muffling signal detected for each range of the rotation speed of the blower fan are in opposite phases, In an air conditioner in which a filter constant corresponding to the current fan rotation speed is selected or a filter having a constant corresponding to the fan rotation speed is selected. The muffling speaker and the means for detecting a muffling signal of the muffling speaker are built in a noise generating portion of the indoor unit main body, and the means for detecting the noise signal are built in a position corresponding to the vertical direction of the noise generating portion of the indoor unit main body. This is achieved by positioning.

Thus, by arranging the noise microphone, the muffling speaker, and the muffling microphone at positions corresponding to the vertical direction of the noise generating portion of the indoor unit main body, the space in the horizontal and vertical directions of the air conditioner is not sufficient. It can be installed in a place without reducing the sound deadening effect.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An air conditioner to which the present invention is applied is composed of an outdoor unit installed outdoors and an indoor unit installed indoors. So-called separate type or integrated type.

FIG. 4 shows a configuration of a silencer of an air conditioner which has been proposed by the present applicant to solve the above-mentioned problems of the prior art, and is a premise to which the present invention is applied.
Reference numeral 1 is a noise source typically shown in an air conditioner, 2 is a noise detection microphone, 3 is a muffling speaker for generating a control sound for muffling, 4 is a muffling microphone, and 5 is a filter. Here, the noise detection microphone 2 is arranged near the noise source 1, and the noise reduction microphone 4 is arranged near the noise reduction speaker 3.

Next, a method for obtaining a constant for determining the characteristics of the filter 5 will be described with reference to FIG. In FIG. 5, reference numeral 12 denotes a noise detection microphone, 13 denotes a speaker that generates a control sound, 14 denotes a muffling microphone that detects sound of a muffling speaker, and 15 denotes a noise microphone 12.
, A digital adaptive filter (DAF) 16 for processing the noise signal to generate a signal for generating a control sound, and 17 for a noise reduction speaker 13 for outputting the noise signal of the signal splitter. A transfer filter for superimposing the transfer function characteristics between the muffling microphones 14 and correcting the speaker characteristics, a signal adder 19 for adding the noise signal x and the muffling signal y to obtain an error signal e, and an output 18 of the transfer function filter 17 A least-squares operation unit (LMS) for adjusting the coefficient of the digital adaptive filter 16 based on the error signal e from the signal adder 19.

The basic operation of the silencer having such a configuration is obtained from the information of the input (signal from the noise detection microphone 12) x of the digital adaptive filter 16 and the output y (-x) of the silence microphone 14. The coefficient of the digital adaptive filter 16 is obtained by the least square calculation unit (LMS) 18 by known adaptive control so that the energy of the error signal e is minimized, and the coefficient is sequentially updated. As a result, a muffling signal having an opposite phase to the noise signal is obtained.

The noise of the air conditioner depends on the rotation speed of the blower fan. As shown in FIG. 7, 1) the rotation speed of the fan is H, 2) the rotation speed of the fan is M, and 3) the rotation of the fan. Peak noise occurs depending on the number L.

First, the rotation speed of the blower fan of the air conditioner is divided into a plurality of ranges from the lowest value to the highest value of the operating range, and the blower fan is rotated in each range. For example, in the case of dividing into three ranges, the operation is performed at the maximum range of rotation speed (H), the noise x1 of the noise source 1 at that time is detected by the noise detection microphone 12, and the noise signal is transmitted to the digital adaptive filter 16 on the one hand. After being input to the transfer filter 17 and superimposed on the transfer function characteristic between the muffling speaker 13 and the muffling microphone 14,
It is supplied to one input terminal of a least squares operation unit (LMS) 18. A noise signal x from the noise microphone 12 is input to the other input terminal of the least square calculation unit (LMS) 18.
1 and an error signal e1 of the muffling signal y1 (-x1) of the speaker 13 from the muffling microphone 14 are supplied.

The least squares calculator (LMS) 18 performs adaptive control so that the energy of the error signal e1 obtained from the information x1 and y1 is minimized, and the coefficients h1, h2, h3... Hn of the digital adaptive filter 16 are used.
Ask for. The rotation speed (M) of the next medium range is also x2, y
2, the least squares operation unit (LMS) 18 performs adaptive control so that the energy of the error signal e2 is minimized.
m2, m3... mn are obtained. Further, even at the lowest range speed (L), the least-squares calculation unit (L) is calculated based on x3 and y3.
In MS) 18, coefficients l1, l2, l3... Ln of the digital adaptive filter 16 are determined by adaptive control so that the energy of the error signal e3 is minimized.

In this way, an appropriate filter constant is sequentially obtained for each range of the number of revolutions of the blower fan and stored in a storage unit of a control microcomputer (not shown) as a table, or each filter is stored. Prepare multiple filters consisting of constant numbers.

When a look-up table is stored in the storage unit of the control microcomputer, a table as shown in the following table is prepared, and an appropriate filter constant corresponding to the current rotational speed of the blower fan is prepared. The characteristic is changed by selecting from the table of the storage unit and setting the constant of the filter.

[0027]

[Table 1] Operating frequency filter constants H h1, h2, h3... Hn mm m1, m2, m3.

Returning to FIG. 4, the description will be continued. The noise from the noise source 1 shown as a representative of the air conditioner is detected by the noise detection microphone 2, and an appropriate filter constant corresponding to the rotation speed of the blower fan at the present time is selected from the table of the storage unit, and the constant is selected. 5 whose characteristics are changed by setting
Is output as a sound signal to the muffling speaker 3 via the amplifier 6 of the next stage. Alternatively, through a proper filter 5 (which may be digital or analog) selected corresponding to the range of the rotational speed of the blower fan at present among a plurality of filters composed of filter constants, and via an amplifier 6 of the next stage. The sound is output to the muffling speaker 3 as an audio signal. Then, the muffling speaker 3 generates a control sound for muffling in response to the noise of the noise source. In addition, when performing actual muffling,
The silencing microphone 4 is unnecessary.

FIG. 6 shows an outline of selecting a filter using the output of the number of revolutions of the blower fan of the control microcomputer. A plurality of filters consisting of respective filter constants are prepared, and the number of rotations 7 of the blower fan at the present time is obtained from the control microcomputer. A filter 5 having a filter constant is selected. That is, the filter 5 is selectively switched according to a command from the control microcomputer. If necessary, the range of the number of rotations can be further divided.

When the noise source in the muffler of the air conditioner configured as described above is searched for by sound intensity, as shown in FIG. 3, the front of the air conditioner (air conditioner) indoor unit, that is, the front grill 10 cm. Was obtained. Fig. 3 (A) shows the noise generation point at the noise frequency of 855 Hz, and Fig. 3 (B) shows 800H.
The noise generation points of z to 1 kHz are displayed.

From the above, it was confirmed that the noise signal was generated from two positions in front of the indoor unit.
Therefore, if the noise detection microphones (noise microphones) are arranged at these two locations, and the muffling speakers and the muffling microphones (muffling microphones) are arranged at positions near these two locations, the muffling of the entire room can be effectively reduced. Can be done.

On the other hand, it is preferable that the means for detecting the noise signal, the muffling speaker and the means for detecting the muffling signal of the muffling speaker do not protrude forward from the indoor unit main body as much as possible and are compact as a whole. Therefore, in the present invention, the noise microphone, the sound deadening microphone, and the sound deadening speaker are arranged as shown in FIGS.

FIG. 2A shows a state in which a noise microphone is built in a noise generating portion of the indoor unit main body, and a muffling speaker and a muffling microphone are arranged at positions corresponding to the noise generating portion below the indoor unit main body. Thus, even in a place where the space in the lateral direction of the air conditioner is not sufficient, the air conditioner can be installed without reducing the sound deadening effect.

FIG. 2B shows a state in which a noise microphone is built in a noise generating portion of the indoor unit main body, and a muffling speaker and a muffling microphone are arranged on both sides of the indoor unit main body. Thus, the muffling speaker and the muffling microphone can be clearly arranged on both sides of the indoor unit main body without taking up space in the vertical direction of the indoor unit main body.

1A and 1B, more practically,
The figure shows the positional relationship between the indoor unit body of the air conditioner, the noise microphone, the muffling speaker, and the muffling microphone. In particular, FIG.
(A) shows a noise microphone built in a noise generating portion of an indoor unit main body, and a sound deadening speaker and a sound deadening microphone built in and integrated on both sides of the indoor unit main body. FIG. 1 (C)
The figure shows a state in which the sound deadening speaker and the sound deadening microphone are built in the noise generating place of the indoor unit main body, and the noise microphone is built in the position below the noise generating place of the indoor unit main body. This makes the design cleaner and the installation work easier.

[0036]

As described above, in the muffler for the air conditioner of the present invention, the noise microphone is built in the noise generating portion of the indoor unit body, and the muffler speaker and the mute microphone are arranged on both sides of the indoor unit body. Thus, the muffling speaker and the muffling microphone can be clearly arranged on both sides of the indoor unit main body without taking up space in the vertical direction of the indoor unit main body. In particular, by integrating the sound deadening speaker and the sound deadening microphone into the indoor unit main body, the design becomes clearer and the installation work becomes easier.

Further, by disposing the muffling speaker and the muffling microphone at the positions corresponding to the vertical noise generating points of the indoor unit main body, the muffling effect can be obtained even in a place where the lateral space of the air conditioner is not sufficient. Can be installed without reduction.

[Brief description of the drawings]

FIG. 1 is a front view and a cross-sectional view of an indoor unit main body of an air conditioner.

FIG. 2 is an arrangement relation diagram of an indoor unit main body and a noise microphone, and a muffling speaker and a muffling microphone.

FIG. 3 is a distribution characteristic diagram of a noise source in the silencer of the air conditioner.

FIG. 4 is a basic configuration of a muffler for an air conditioner of the present invention.

FIG. 5 is a block diagram for determining filter characteristics according to the present invention.

FIG. 6 is a block diagram of fan rotation speed and filter selection.

FIG. 7 shows a fan speed range and a noise generation state.

FIG. 8 is a conventional duct type silencer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Noise source of air conditioner 2,12,22 Microphone for noise detection 3,13,23 Silent speaker 4,14,24 Silent microphone 5 Filter 6 Amplifier 7 Fan speed 15 Signal splitter 16 Digital adaptive filter (DAF) 17 Transmission filter 18 Least-square operation unit (LMS) 19 Signal adder 21 Air-conditioning duct 25 Signal splitter 26 Digital adaptive filter (DAF) 27 Transmission filter 28 Least-square operation unit (LMS)

Claims (4)

[Claims] 1. An air conditioner having at least a blower fan and a suction port and a discharge port for circulating air in a room to be conditioned using the blower fan, which is a noise source for a blower fan of an indoor unit. It comprises a means for detecting a noise signal, a filter to which the noise signal is input, a muffling speaker to which the output signal of this filter is applied, and a means for detecting the muffling signal of the muffling speaker, the filter rotating the blower fan. It has a plurality of filter constants calculated so that the noise signal and the muffling signal detected for each number range have opposite phases, and selects a filter constant corresponding to the rotation speed of the blower fan at the present time or In an air conditioner in which a filter having a constant number corresponding to the rotation speed of a blower fan is selected, a means for detecting the noise signal is installed in the noise generating part of the indoor unit body. A muffler for an air conditioner, wherein the muffling speaker and means for detecting a muffling signal of the muffling speaker are arranged on both sides of the indoor unit main body. 2. The muffler for an air conditioner according to claim 1, wherein the muffling speaker and a means for detecting a muffling signal of the muffling speaker are provided on both sides of the indoor unit main body. 3. An air conditioner having at least a blower fan and a suction port and a discharge port for circulating air in a room to be conditioned using the blower fan, which is a noise source for a blower fan of an indoor unit. Means for detecting a noise signal, a plurality of filters to which the noise signal is input, a muffling speaker to which an output signal of the filter is applied, and means for detecting a muffling signal of the muffling speaker, wherein the plurality of filters are It has a plurality of filter constants calculated so that the noise signal and the muffling signal detected for each range of the rotation speed of the blower fan are in opposite phases, and a filter constant corresponding to the rotation speed of the blower fan at the present time. In the air conditioner, which selects or selects a filter having a constant corresponding to the rotation speed of the blower fan, the means for detecting the noise signal includes a noise of the indoor unit main body. A muffler for an air conditioner, characterized in that the muffler speaker is installed in a place where the noise is generated, and the means for detecting a mute signal of the muffler speaker is arranged at a position corresponding to a noise occurrence point in the vertical direction of the indoor unit body. . 4. An air conditioner having at least a blower fan and a suction port and a discharge port for circulating air in a room to be conditioned using the blower fan, which is a noise source for a blower fan of an indoor unit. The noise filter includes a unit for detecting the noise signal, a plurality of filters for inputting the noise signal, a muffling speaker to which the output signal of the filter is applied, and a unit for detecting the muffling signal of the muffling speaker. It has a plurality of filter constants calculated so that the noise signal and the muffling signal detected for each range of the rotation speed of the blower fan are in opposite phases, and a filter constant corresponding to the rotation speed of the blower fan at the present time. In the air conditioner which selects or selects a filter having a constant corresponding to the rotation speed of the blower fan, the mute speaker and a mute signal of the mute speaker are provided. The air conditioner is characterized in that the means for detecting the noise is built in the noise generating portion of the indoor unit main body, and the means for detecting the noise signal is built in and arranged at a position corresponding to the vertical direction of the noise generating portion of the indoor unit main body. Silencer.