JPH0694349A - Sound muffling device in cooling device - Google Patents

Abstract

PURPOSE:To enable an active control to be attained for muffling a noisy sound from a cooling device and provide a positive noisy sound muffling from two openings. CONSTITUTION:A calculator 40 operates a sound echo transmittance function on the basis of a received sound received from an auxiliary microphone 35 and generates a control sound from a speaker 33 in response to the sound echo transmittance function. Noisy sound generated from a compressor 28 is diminished at an opening 31a with the control sound received from the speaker 33. In this case, the operator 40 sets the sound echo transmittance function so as to diminish the control sound received from the other speaker 34 at the opening 31a. Accordingly, it is possible to perform a positive sound muffling at each of the openings 31a and 31b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for use in a cooling device such as a refrigerator, and more particularly to a muffler for a cooling device which actively cancels noise from a machine room containing a compressor.

[0002]

2. Description of the Related Art In a cooling device using a compressor, for example, a refrigerator, it is often installed in a living room of a general household, and since it is continuously operated regardless of the season, Noise reduction is an issue. In this case, the most problematic noise source of the refrigerator is noise from the machine room in which the compressor and the piping system connected to the compressor are stored. That is, in the above machine room, the compressor itself generates comparatively large noise (operation noise of the compressor motor, fluid noise due to compressed gas, mechanical noise in movable mechanical elements of the compression mechanism portion, etc.) and the compressor is connected to the compressor. The generated piping system also generates noise due to its vibration, and such machine room noise accounts for the majority of refrigerator noise. Therefore, suppressing the noise from the machine room greatly contributes to the noise reduction of the entire refrigerator.

Therefore, in the past, in order to reduce noise from the machine room, in addition to noise reduction of the compressor itself (for example, use of a rotary type compressor), improvement of the vibration isolation support structure of the compressor and piping system. By reducing the vibration in the vibration propagation path by improving the shape of the machine, or by arranging a sound absorbing member and a sound insulating member around the compressor and the piping system, the sound absorption volume and noise in the machine room are increased. The transmission loss is being increased.

However, in the machine room of a refrigerator,
Since it is necessary to release the heat generated by the driving of the compressor to the outside, openings for heat dissipation are provided at a plurality of locations, and noise leaks out from these openings. Therefore, the conventional noise reduction measures as described above are naturally limited, and the noise level reduction effect can be expected to be only about 2 dB (A).

On the other hand, in recent years, with the development of electronics application technology, especially acoustic data processing circuits and acoustic control technology, active noise control is performed by utilizing acoustic wave interference to reduce noise. The application of technology is drawing attention. That is, this active control basically converts a sound from a noise source into an electric signal by a sound receiver (for example, a microphone) provided at a specific position, and converts the electric signal into a signal processed by a calculator. By operating the control sounder (for example, a speaker) based on this, an artificial sound having the same wavelength and the same amplitude as that of the original sound (sound from the noise source) at the control target point is generated from the sounder. , The original sound is to be attenuated by causing the artificial sound and the original sound to interfere with each other.

In order to muffle the noise from the compressor using the above-mentioned muffling technology, the noise from the compressor is converted into an electric signal by a vibration sensor or a microphone, and the electric signal is converted into a signal processed by an arithmetic unit. Based on this, by generating a control sound from a speaker arranged in the machine room, the noise is attenuated at the opening which is the control target point.

By the way, when a plurality of openings are located in the machine room of the refrigerator, it is necessary to muffle noise radiated from those openings, so a muffling system should be provided for each opening. I have to.

FIG. 9 shows a schematic construction in which two sets of muffling systems are provided. That is, the first opening 2 and the second opening 3 are provided at both ends of the machine room 1 of the refrigerator,
A first silencing system 4 and a second silencing system 5 are provided corresponding to each of the openings 2 and 3. In this case, since the muffling systems 4 and 5 have the same structure, only the first muffling system 4 will be described, and the structure of the second muffling system 5 will be denoted by reference numerals in parentheses and will not be described. That is, the compressor 6 is additionally provided with a first (second) vibration sensor 7 (8). In addition, the first (second) microphone 9 (10) and the first (second) microphone 9 (10) corresponding to the first (second) opening 2 (3) are provided.
A (second) speaker 11 (12) is provided.

Here, the noise from the compressor 6 is reduced to S,
The detection signal of the first (second) vibration sensor 7 (8) is set to P1.
(P2), the acoustic transfer function from the compressor 6 to the first (second) vibration sensor 7 (8) is GSP1 (GSP2), and the compressor 6 is the first (second) microphone 9 (1).
0) to the acoustic transfer function GSO1 (GSO2), and the control sound emitted from the first (second) speaker 11 (12) to A
1 (A2), the acoustic transfer function from the first (second) speaker 11 (12) to the first (second) microphone 9 (10) is GA1O1 (GA2O2), the first (second) vibration sensor 7
Assuming that the acoustic transfer function from (8) to the first (second) speaker 11 (12) is G1 (G2), the first microphone 9 in the first muffling system 4 detects noise from the compressor 6 and Since the control sound from the first speaker 11 is received, O1 = S.GSO1 + A1.GA1O1 A1 = P1.G1 P1 = S.GSP1. Here, in order to muffle sound in the first opening 2, since O1 = 0, the transfer function G1 in the first muffling system 4 is G1 = GSO1 /
GA1O1 and GSP1 can be obtained. Similarly, in order to muffle the second opening 3, the transfer function G2 in the second muffling system 5 is G2 = GSO2 / GA2O2.GSP.
You can get 2.

Accordingly, the control sounds A1 and A2 obtained by multiplying the acoustic transfer functions G1 and G2 with the electric signals P1 and P2 from the vibration sensor are generated from the first and second speakers 11 and 12, respectively. The noise in the parts 7 and 8 can be silenced.

[0011]

By the way, although the noise from the compressor 6 can be silenced at the openings 2 and 3 provided in the machine room 1 by the silencing systems 4 and 5, the one opening 2 is provided. From (3), the speaker 12 (11) provided corresponding to the other opening 3 (2)
The control sound from is emitted. Therefore, with the above-mentioned conventional configuration, the silencing effect of the silencing system as a whole is not sufficient, and this point remains as an unsolved problem.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to surely muffle sound in a structure that muffles sounds from the first and second openings provided in the machine room. It is to provide a silencer for a cooling device.

[0013]

According to the present invention, there is provided a vibration sensor for converting a sound generated by driving a compressor housed in a machine room into an electric signal, and first and second vibration sensors provided in the machine room. First and second installed respectively near the opening
Auxiliary sound receivers, first and second control sound generators provided corresponding to the first and second openings in the machine room, and the first and second auxiliary sound receivers. A sound transfer function is calculated based on an electric signal from the sounding device, and the first and second control sounders are operated by an electric signal obtained by multiplying the sound transfer function by the electric signal from the vibration sensor. And a second computing unit, and in a silencer of a cooling device that actively cancels the sound radiated to the outside through each of the openings, each computing unit includes an acoustic transfer function based on the following computing expression. Which is calculated.

G1 = (GA2O1 · GSO2 −GA2O2 · GSO1) / GSP ·
(GA1O1 ・ GA2O2－GA1O2 ・ GA2O1) G2 ＝ (GA1O2 ・ GSO1 −GA1O1 ・ GSO2) / GSP ・
(GA1O1 ・ GA2O2-GA1O2 ・ GA2O1) where G1 is the acoustic transfer function from the vibration sensor to the first control sounder, G2 is the transfer function from the vibration sensor to the second control sounder, and GSP is the compressor. Acoustic transfer function reaching the vibration sensor, GA2O1 is an acoustic transfer function reaching from the second control sounder to the first auxiliary sound receiver, and GA2O2 is reaching from the second control sounder to the second auxiliary sound receiver. Acoustic transfer function, GA1O1 is an acoustic transfer function from the first control sounder to the first auxiliary sound receiver, GA1O2 is an acoustic transfer function from the first control sounder to the second auxiliary sound receiver, GSO1 is the acoustic transfer function from the compressor to the first auxiliary sound receiver, GSO
2 indicates the acoustic transfer function from the compressor to the second auxiliary sound receiver.

Further, a sound receiver for converting a sound generated by driving a compressor housed in the machine room into an electric signal, and a sound receiver installed near the first and second openings provided in the machine room, respectively. First and second auxiliary sound receivers, first and second control sound generators respectively provided corresponding to the first and second openings in the machine chamber, and the first
And the acoustic transfer function is calculated based on the electric signal from the second auxiliary sound receiver, and the first electric signal is obtained by multiplying the acoustic transfer function by the electric signal from the sound receiver.
And a first and a second computing unit for operating a second control sounder, wherein the sound receiving device is a silencer for a cooling device that actively cancels the sound radiated to the outside through the openings. An echo canceller for canceling the echo component from the first and second control sounding devices included in the electric signal output from the device is provided, and each of the arithmetic units calculates an acoustic transfer function based on the following arithmetic expression. You may make it calculate.

G1 = (GA2O1 · GSO2 -GA2O2 · GSO1) / GSP ·
(GA1O1 ・ GA2O2－GA1O2 ・ GA2O1) G2 ＝ (GA1O2 ・ GSO1 −GA1O1 ・ GSO2) / GSP ・
(GA1O1 ・ GA2O2-GA1O2 ・ GA2O1) where G1 is the acoustic transfer function from the sound receiver to the first control sounder, G2 is the transfer function from the sound receiver to the second control sounder, and GSP is Acoustic transfer function from compressor to sound receiver, GA2O1 is acoustic transfer function from second control sounder to first auxiliary sound receiver, GA2O2 is second sound reception from second control sounder Transfer function to the sound generator, GA1O1 is the sound transfer function from the first control sounder to the first auxiliary sound receiver, and GA1O2 is the sound from the first control sounder to the second auxiliary sound receiver. Transfer function, GSO1 is first from compressor
, GSO2 represents the acoustic transfer function from the compressor to the second auxiliary sound receiver.

[0017]

According to the silencer of the cooling device of the first aspect,
The noise from the compressor is radiated to the outside from the first and second openings provided in the machine room. At this time, the noise from the compressor is converted into an electric signal by the vibration sensor, and the first and second arithmetic units operate the corresponding control sounder based on the signal obtained by processing the electric signal. Thus, the noise from the compressor is silenced at each opening.

When the sound is muted as described above, the control sound from the control sounding device provided corresponding to the other opening reaches the one opening. At this time, the computing unit computes an acoustic transfer function that silences the control sound from the other control sounder in addition to the noise from the compressor, so that one opening corresponds to the other opening. Even if the control sound from the control sound generator arrives, the noise from the compressor can be surely silenced without being affected by the control sound.

According to the muffler of the cooling device of the second aspect, the noise from the compressor is detected by the sound receiver instead of the vibration sensor.

In the case of such a configuration, the sound receiver has the first
Also, although the control sound (echo sound) from the second control sounder arrives and is included in the electric signal, the echo component included in such an electric signal is invalidated by the echo canceller. However, similarly to the silencer for a cooling device according to claim 1, even if the control sound from the control sounding device corresponding to the other opening reaches the one opening, it is not affected by the control sound, and The noise can be surely silenced at each opening.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a refrigerator will be described below with reference to FIGS. In FIG. 2 showing the entire configuration of the refrigerator, 21 is a refrigerator main body, and inside thereof, a freezing compartment 22, a refrigerating compartment 23 and a vegetable compartment 24 are provided in this order from above. A refrigeration system is provided inside the refrigerator, and these components will be described. That is, 25 is a cooler arranged at the back of the freezing compartment 22, 26 is a fan for directly supplying the cool air generated by the cooler 25 to the freezing compartment 22 and the refrigerating compartment 23, and 27 is a rear surface of the refrigerator body 1. A machine room formed in the lower part of the side, in which a rotary type compressor 28, a condenser pipe 29, and a defrosting water evaporator 30 using so-called ceramic fins are housed. In the driving state of the compressor 28, the refrigerant from the compressor 28 is supplied to the cooler 25 through a refrigerant passage (not shown) to be cooled, and the fan 26 is driven to drive the cooler 2
Heat is exchanged between the No. 5 and the inside of the refrigerator.

FIG. 3 (here, the condenser pipe 2
9 and the defrosting water evaporator 30 are not shown), the machine room 27 has a rectangular opening only on its back surface, and this opening part covers the machine room cover.
It is closed by 31. At this time, the peripheral edge of the machine room cover 31 is airtightly attached to the opening edge of the machine room 27, and both edges in the figure are elongated rectangular heat-dissipating members for heat dissipation. First opening 3 of
1a and 31b are formed. In other words, the machine room cover
In the mounted state of 31, the machine room 27 has the heat dissipation opening 31.
It is in a closed state except for a and 31b. The machine room cover 31 is formed of a material (for example, a metal such as iron) having excellent thermal conductivity and large sound transmission loss.

Further, in FIG. 3, reference numeral 32 denotes a vibration sensor attached to the compressor 28, which is provided so as to convert the vibration sound of the compressor 28, which is a noise source, into an electric signal. Reference numerals 33 and 34 denote first and second loudspeakers, which are first and second control sound generators arranged in the machine room 27. For example, this is a back wall portion of the machine room 27 (of the refrigerator main body 21). Heat dissipation opening 31 in the bottom wall)
It is attached and supported in an embedded manner at a portion near a and 31b.
Reference numerals 35 and 36 denote first and second auxiliary microphones, which are first and second auxiliary sound receivers provided in the heat dissipation openings 31a and 31b. These are the noise from the compressor 28 and the first and second auxiliary microphones. Sounds from the second speakers 33 and 34 are received to monitor the silencing effect of the speakers 33 and 34.

Therefore, as shown in FIG. 1, the first speaker 33 and the first auxiliary microphone 35 form a part of the first muffling system 37, and the second speaker 34 and the second speaker 34. The auxiliary microphone 36 has a second muffling system 38.
Form part of the. Here, in the first and second speakers 32 and 34, the electric signal P from the vibration sensor 34 is processed by the first calculator 40 and the second calculator 41 in the anti-phase sound generation circuit 39. It is operated by a control signal, and the processing of the electric signal as described above is performed based on the silencing principle by active control as described below.

That is, the muffling principle by active control will be briefly described with reference to FIG. 4. Since the muffling principles of the first and second muffling systems 37 and 38 are the same,
Only the first silencing system 37 will be described, and description of the second silencing system 38 will be omitted. That is, the sound generated by the compressor 28, which is the noise source, is S1, the sound generated by the first speaker 33 is S2, the vibration sound detected by the vibration sensor 32 is R1, and the first opening which is the control target point. Three
When the sound received by the first auxiliary microphone 35 provided in 1a is R2, and the sound transfer function and the acoustic transfer function between the input points are T11, T21, T12, and T22, two inputs The following equation holds as a two-output system.

[0026]

[Equation 1] Therefore, the sound S2 to be generated by the first speaker 35 is S2 = (-T12.R1 + T11.R2) / (T11) from the above equation.
.T22-T12.T21). In this case, since the target is to make the sound level at the first opening 31a zero, R2 can be set to 0. As a result, S2 = R1.T12 / (T12.T21-T11.T22)
Becomes As can be understood from this formula, the first opening 3
In order to reduce the sound R2 at 1a to zero, the sound R1 received by the vibration sensor 32 is filtered by the calculation formula F = T12 / (T12 · T21−T11 · T22) (1). Processed sound S
If 2 is generated from the first speaker 33, the sound level at the first opening 31a can theoretically be set to zero, and the first computing unit 40 can The first speaker 3 while performing processing (calculation) at high speed
3 is configured to give a control signal.

Now, in the above equation (1), F = G, T
Substituting 12 = Gso, T21 = Gam, T11 = Gsm, T22 = Gao, G = Gso / (Gso.Gam-Gsm.Gao) (2). Here, the meanings of Gso, Gam, Gsm, and Gao are such that the subscripts at the front stage correspond to the input side and the subscripts at the rear stage correspond to the output side (response side). For example, Gam is the input signal to the first speaker 33. As the input side, and the first auxiliary microphone 3
The acoustic transfer function when the output signal from 5 is measured on the output side is shown. When the noise from the compressor 28 is detected by the vibration sensor 32, the vibration sensor 32 does not receive the sound from the first speaker 33, so that Gam can be regarded as zero.
Therefore, the above equation (2) is G = -Gso / (Gsm * Gao) (3). Here, since Gso / Gsm = Gmo, the above equation (3) becomes G = -Gmo / Gao (4). In other words, the electric signal from the vibration sensor 32 is filtered by the filter corresponding to G shown in the above equation (4) to generate a processed sound from the first speaker 33, so that the first opening 31 a The sound level can theoretically be zero. The same applies to the second silencing system 38.

On the other hand, in the case of the refrigerator constructed as described above, the noise level generated in the machine room 27 in response to the driving of the compressor 28 is, as shown in FIG. The state is such that it has the property of increasing in the 5 kHz band. Of the noises corresponding to each of these bands, the noise on the high frequency side can be attenuated by the transmission loss in the machine room cover 31 or the like, and can be easily installed by installing an appropriate sound absorbing member in the machine room 27. Therefore, the active control of noise by the vibration sensor 32, the first and second loudspeakers 33, 34 and the first and second arithmetic units 40, 41 as described above is 70
The target frequency may be 0 Hz or less.

Further, in the case of performing the active control of the noise as described above, it is theoretically possible to control the noise in the machine room 27 so as to be a one-dimensional plane traveling wave. Also in the above, it becomes important to perform it easily and accurately. Therefore, in the present embodiment, of the three dimensions D, W, and H in the depth, width, and height directions of the machine room 27 shown in FIG. Set larger than D and H (specifically, W =
By setting 600 mm and D = H = 200 mm), the standing wave of the sound in the machine room 27 is constituted only in the first mode. That is, for example, when the machine room 27 is assumed to be a rectangular cavity, the following equation holds.

[0030]

[Equation 2] Here, f is the resonance frequency (Hz), Nx, Ny, Nz are the modes in the X, Y, Z directions, and Lx, Ly, Lz are the dimensions in the machine room 7 in the X, Y, Z directions ( That is, D, W,
H) and C are sound speeds. Therefore, from the above equation, X, Y, Z
The frequencies fx, fy, f of the first standing wave in each direction
We can find z.

That is, as described above, the depth dimension D = 2
When the width dimension W = 600 mm and the height dimension H = 200 mm are set to 00 mm, the frequency fx of the first standing wave in the X direction is Ny = Nz = 0, and the sound velocity C = 340 m.
/ Sec,

[Equation 3] Similarly, the frequencies fy and fz of the first standing wave in the Y and Z directions are

[Equation 4] Becomes As a result, the target frequency (= 700H
z) Below, the standing wave of the noise in the machine room 27 is established only in the mode in the Y direction (width direction), and the noise in the machine room 27 is regarded as a one-dimensional plane traveling wave. be able to. Therefore, at the time of noise reduction by active control of noise using the loudspeakers 33, 34, theoretical treatment of the wavefront becomes easy, and the noise reduction control can be performed easily and accurately.

On the other hand, as shown in FIG. 1, the anti-phase sound generating circuit 39 is adapted to receive a drive command to the compressor 28 (hereinafter referred to as a comp-on signal Sa). The compressor 28 and the fan 26 are driven during the output period of the comp-on signal Sa.

The adaptive control means 42 (43) of the anti-phase sound generation circuit 39 has the first (second) auxiliary microphone 35.
The electrical signal from (36) is sampled to monitor the silencing effect of the active control described above. Then, when the monitoring result is within the predetermined allowable range, the active control is repeatedly executed. Thus, while the compon signal is being input, the control signal corresponding to the noise accompanying the driving of the compressor 28 is the first (second) speaker 33 (3).
Since it is output from 4) and active control is performed in real time, even if the acoustic component from the compressor 28 fluctuates, the noise can be attenuated by following the fluctuation.

On the other hand, when the result of monitoring the sound deadening effect is out of the allowable range, the adaptive control means 42 (43) changes the calculation coefficient (transfer function) in the calculator 40 (41) in the direction of increasing the sound deadening effect. Change by a predetermined amount to
As a result, the output from the speaker 33 (34) is adjusted so that the silencing effect of the artificial sound from the speaker 33 (34) falls within the allowable range.

In the following, the first (second) arithmetic unit 4
The function of 0 (41) will be described. That is, the freezing room 22
When the temperature of the vibration sensor 3 rises and reaches a predetermined temperature, a compon signal is output, and the compressor 28 is driven accordingly. Therefore, the vibration sensor 3 attached to the compressor 28
2 vibrates. Then, the first computing unit 40 samples the vibration signal (acoustic signal) from the vibration sensor 32 during the input period of the compon signal, and processes the sampled acoustic signal based on the acoustic transfer function described above. After that, a control signal based on the processing is output. As a result, the control signal is given from the first arithmetic unit 40 to the first speaker 33, and accordingly the first speaker 3 is supplied.
Since the control sound is emitted from No. 3, the noise accompanying the driving of the compressor 28 and the control sound from the first speaker 33 interfere with each other in the first opening 31a, and the sound level thereof is lowered. Active control is performed.

Here, the first (second) arithmetic unit 40 (4
1) The procedure for obtaining the acoustic transfer function will be described. That is, as shown in FIG. 7, the noise from the compressor 28 is S, the detection signal of the vibration sensor 32 is P, the acoustic transfer function from the compressor 28 to the vibration sensor 32 is GSP, and the compressor 2
The acoustic transfer function from the eighth to the first (second) auxiliary microphone 35 (36) is GSO1 (GSO2), and the control sound emitted from the first (second) speaker 33 (34) is A1 (A
2), from the first (second) speaker 33 (34) to the first
The acoustic transfer function reaching the (second) auxiliary microphone 35 (36) is calculated from GA1O1 (GA2O2) and the vibration sensor 32 to the first
If the acoustic transfer function reaching the (second) speaker 33 (34) is G1 (G2),

[Equation 5] Therefore, the electric signal P from the vibration sensor 32 is added to the above-mentioned G
The first and second speakers 33 and 3 by multiplying 1 and G2
By generating the control sound from No. 4, not only the noise from the compressor 28 but also the control sound from the speakers 34 and 33 located on the opposite side can be silenced in the first and first openings 31a and 31b.

FIG. 8 shows a second embodiment of the present invention.
In the second embodiment, an example in which noise from the compressor 28 is detected by the microphone 44 that is a sound receiver is shown.
In this case, each speaker 33, 34 to the microphone 44
The echo cancellers 45 and 46 are used to invalidate the echo components up to.

That is, the acoustic transfer function from the first speaker 33 to the microphone 44 is GA1M, and the acoustic transfer function from the second speaker 34 to the microphone 44 is GA2M.
Then, the signal M input to the microphone 44 becomes M = S.multidot.GSM + A1.multidot.GA1M + A2.multidot.GA2M, which is a signal (A1.multidot.GA1M + A2.multidot.A) corresponding to the echo component from each speaker 33, 34 to the microphone 44.
GA2M) is included. Therefore, the signals (A1.GA1M + A2.GA2M) which are echo components due to the acoustic system are electrically subtracted by the echo cancellers 45 and 46 shown in FIG. As a result, the signal M'output from the microphone 44 and corrected by the echo cancellers 45 and 46 becomes M '= M- (A1.GA1M + A2.GA2M) = S.GSM, which is the vibration sensor 32 in the first embodiment. Similarly to the detection by the above, the sound reception signal from the microphone 44 can be corrected to a function of only the noise from the compressor 28. Therefore, the following acoustic transfer function can be obtained in the same manner as in the first embodiment.

[0039]

[Equation 6] Then, a signal obtained by multiplying the output signal from the microphone 44 by the acoustic transfer functions G1 and G2 is used for each speaker 33,
By outputting from the speaker 34, the noise from the compressor 28 can be surely silenced while preventing the influence of the housing from the speakers 33 and 34 to the microphone 44.

According to the above constitutions, the refrigerator main body 2
When noise from the compressor 28 radiated from the first and second openings 31a and 31b for heat radiation provided on both sides of the first machine room 27 is silenced by the control sound from the speakers 33 and 34, A speaker 34 located on the opposite side,
Since the acoustic transfer functions of the arithmetic units 40 and 41 are set so as to mute the control sound from the 33, unlike the conventional example in which two sets of muffling systems are simply provided corresponding to the two openings. The noise in the openings 31a and 31b can be surely silenced.

[0041]

As is apparent from the above description, according to the muffler of the cooling device of the first aspect, based on the electric signal from the auxiliary sound receiver provided corresponding to one opening. A calculator that calculates an acoustic transfer function for silencing the noise from the compressor, and an acoustic transfer function that also silences the control sound from the control sounder provided corresponding to the other opening. With this configuration, in the configuration in which the sound from the first and second openings provided in the machine room is silenced, there is an excellent effect that the sound can be reliably silenced.

Further, according to the silencer of the cooling device of the second aspect, when the sound receiver is used to detect the noise of the compressor, the control from the control sounder which the sound receiver receives the sound. Since we have an echo canceller that invalidates the sound,
Similar to the sound deadening device for a cooling device according to claim 1, while using the sound receiver, the sound can be surely muted in the structure for muting sounds from the first and second openings provided in the machine room. It has an excellent effect that it can be done.

[Brief description of drawings]

FIG. 1 is a schematic electrical configuration diagram showing a first embodiment of the present invention.

[Fig. 2] Vertical sectional view of the refrigerator

FIG. 3 is an exploded perspective view showing a state where a cover is removed from a machine room of a refrigerator.

FIG. 4 is a schematic configuration diagram showing a silencing principle by active control.

FIG. 5 is a schematic perspective view showing dimensional relationships of machine rooms.

[Fig. 6] Noise level characteristic diagram

FIG. 7 is a schematic diagram for explaining a silencing principle by two silencing systems.

FIG. 8 is a view corresponding to FIG. 7 showing a second embodiment of the present invention.

9 is a diagram corresponding to FIG. 7 showing a conventional example.

[Explanation of symbols]

21 is a refrigerator main body (cooling device), 27 is a machine room, 28 is a compressor, 31 is a machine room cover, 31a is a first opening, 31b is a second opening, 32 is a vibration sensor, 33
Is a first speaker (first control sounder), and 34 is a second speaker
Speaker (second control sounder), 39 is a reverse-phase sound generation circuit, 40 is a first arithmetic unit, 41 is a second arithmetic unit, 4
Reference numerals 2 and 43 are adaptive control means, 44 is a microphone (sound receiver), and 45 and 46 are echo cancellers.

Claims (2)

[Claims] 1. A vibration sensor for converting a sound generated by driving a compressor housed in a machine room into an electric signal, and a vibration sensor installed in the vicinity of a first opening and a second opening provided in the machine room, respectively. First and second auxiliary sound receivers, first and second control sound generators respectively provided corresponding to the first and second openings in the machine chamber, and the first and second control sound generators.
And the acoustic transfer function is calculated based on the electric signal from the second auxiliary sound receiver, and the first and second controls are performed by the electric signal obtained by multiplying the acoustic transfer function by the electric signal from the vibration sensor. First and second operating sound generators
And a silencer for a cooling device that actively cancels the sound radiated to the outside through each of the openings, each of the calculators calculates an acoustic transfer function based on the following equation. A silencer for a cooling device, which is characterized in that G1 = (GA2O1 ・ GSO2 − GA2O2 ・ GSO1) / GSP ・
(GA1O1 ・ GA2O2－GA1O2 ・ GA2O1) G2 ＝ (GA1O2 ・ GSO1 −GA1O1 ・ GSO2) / GSP ・
(GA1O1 ・ GA2O2-GA1O2 ・ GA2O1) where G1 is the acoustic transfer function from the vibration sensor to the first control sounder, G2 is the transfer function from the vibration sensor to the second control sounder, and GSP is the compressor. Acoustic transfer function reaching the vibration sensor, GA2O1 is an acoustic transfer function reaching from the second control sounder to the first auxiliary sound receiver, and GA2O2 is reaching from the second control sounder to the second auxiliary sound receiver. Acoustic transfer function, GA1O1 is an acoustic transfer function from the first control sounder to the first auxiliary sound receiver, GA1O2 is an acoustic transfer function from the first control sounder to the second auxiliary sound receiver, GSO1 is the acoustic transfer function from the compressor to the first auxiliary sound receiver, GSO
2 indicates the acoustic transfer function from the compressor to the second auxiliary sound receiver. 2. A sound receiver for converting a sound generated by driving a compressor housed in the machine room into an electric signal, and a sound receiver installed near the first and second openings provided in the machine room, respectively. First and second auxiliary sound receivers, first and second control sound generators provided corresponding to the first and second openings in the machine chamber, respectively, and the first and second control sound generators. The acoustic transfer function is calculated based on the electric signal from the second auxiliary sound receiver, and the first and second controls are performed by the electric signal obtained by multiplying the acoustic transfer function and the electric signal from the sound receiver. In a silencer of a cooling device, which is provided with first and second calculators for operating a speaker, and which actively cancels the sound radiated to the outside through each of the openings, the silencer outputs the sound. The first included in the electrical signal
And an echo canceller for canceling the echo component from the second control sounder, wherein each of the computing units computes an acoustic transfer function based on the following computing equation. . G1 = (GA2O1 ・ GSO2 − GA2O2 ・ GSO1) / GSP ・
(GA1O1 ・ GA2O2－GA1O2 ・ GA2O1) G2 ＝ (GA1O2 ・ GSO1 −GA1O1 ・ GSO2) / GSP ・
(GA1O1 ・ GA2O2-GA1O2 ・ GA2O1) where G1 is the acoustic transfer function from the sound receiver to the first control sounder, G2 is the transfer function from the sound receiver to the second control sounder, and GSP is Acoustic transfer function from the compressor to the sound receiver, GA2O1 is an acoustic transfer function from the second control sounder to the first auxiliary sound receiver, and GA2O2 is a second auxiliary sound reception from the second control sounder Transfer function to the sound generator, GA1O1 is the sound transfer function from the first control sounder to the first auxiliary sound receiver, and GA1O2 is the sound from the first control sounder to the second auxiliary sound receiver Transfer function, GSO1 is first from compressor
, GSO2 represents the acoustic transfer function from the compressor to the second auxiliary sound receiver.