JPH03264793A - Silencer for cooling device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention relates to a silencer used in a cooling device such as a refrigerator;
In particular, the present invention relates to a silencer for a cooling device that actively cancels out noise from a machine room housing a compressor.

(Prior Art) Cooling devices that use compressors, such as refrigerators, are often installed in the living space of ordinary households.
Moreover, since they are operated continuously regardless of the season, reducing noise has become an issue. in this case,
The most problematic noise source for refrigerators is noise from the compressor, the piping system connected to it, or the machine room in which it is housed. That is, in the machine room, the compressor itself generates relatively loud noises (compressor motor operating noise, fluid noise due to compressed gas, mechanical noise from movable mechanical elements of the compression mechanism, etc.), and also The piping system also generates noise due to its vibrations, and such machine room noise accounts for most of the refrigerator noise. Therefore, suppressing the noise from the machine room greatly contributes to reducing the noise of the refrigerator as a whole.

Therefore, conventional measures to reduce noise from the machine room include reducing the noise of the compressor itself (for example, using a rotary compressor), improving the vibration-proof support structure of the compressor, and improving the shape of the piping system. By doing this, vibration damping in the vibration propagation path can be achieved, or
By arranging sound absorbing members and sound insulating members around the compressor and the piping system, attempts are being made to increase the amount of absorption in the machine room and to increase the noise transmission loss.

However, in general, the machine room of a refrigerator has multiple openings for heat radiation because it is necessary to release the heat generated by the compressor to the outside, and noise can leak outside from these openings. It turns out. For this reason, the conventional noise reduction measures as described above naturally have a limit, and the effect of reducing the noise level can only be expected to be about 2 dB (A) at most.

On the other hand, in recent years, with the development of electronics application technology, especially acoustic data processing circuits and acoustic control technology, the application of active noise control technology, which reduces noise using sound wave interference, has attracted attention. has been done. In other words, this active control basically converts the sound from the noise source into an electrical signal using a sound receiver (for example, a microphone) installed at a specific location, and then converts this electrical signal into a signal processed by a computing device. Based control sound generator (e.g. speaker)
By operating the generator, an artificial sound is generated from the sound generator that has the opposite phase, the same wavelength, and the same amplitude as the original sound (sound from the noise source) at the control target point, and this artificial sound and the original sound interfere. The idea is to attenuate the original sound by doing this.

In addition, in order to realize such active control, it is necessary to correct characteristic fluctuations due to aging of components constituting the signal system for noise reduction and characteristic fluctuations due to ambient temperature. For this reason, in practical use, the calculation coefficient (acoustic transfer function) of the arithmetic unit is corrected to follow the fluctuation of the silencing ability. An auxiliary sound receiver (for example, a microphone) that monitors the silencing effect of the sound generator, and a system that changes the calculation coefficient of the calculator by a predetermined amount and It has also been considered to perform so-called adaptive control in which a control means is provided that performs the changing operation until the monitor result falls within the allowable range, thereby constantly maintaining the silencing ability at an optimum level during active control.

(Problem to be Solved by the Invention) By the way, the component parts such as the microphone provided for the above-mentioned adaptive control are used only for that adaptive control, so they are not cost-effective. In this case, the added value cannot be said to be sufficiently high, and improvement in this point is desired.

The present invention has been made in view of the above circumstances, and its purpose is to actively cancel the noise accompanying the compressor drive, and to adjust the active control conditions associated with the compressor drive based on the sound reception result by the auxiliary sound receiver. In a device equipped with a silencing function that changes as appropriate, the auxiliary sound receiver can also be used to detect malfunctions in the components of the refrigeration system that are the cause of abnormal operation of the compressor. An object of the present invention is to provide a silencing device for a cooling device that can improve the added value of a cooling device.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention provides a detection means for converting sound generated by driving a compressor housed in a machine room into an electrical signal. , in a silencer for a cooling device, which is provided with a control sound generator that generates an artificial sound based on a signal processed by a computing unit from the above electric signal, and which actively cancels the sound of the compressor by interference with the above artificial sound. ,
An auxiliary sound receiver is provided to monitor the silencing effect of the control sound generator at predetermined intervals, and when the result of monitoring by the auxiliary sound receiver is outside a predetermined tolerance range, the calculation coefficient of the arithmetic unit is calculated. A control means is provided to change the frequency by a predetermined amount and to perform the changing operation until the monitored result falls within the allowable range, and the sound reception frequency characteristic is measured by the auxiliary sound receiver when the refrigeration system is normally driven. A storage means is provided for storing the sound reception frequency characteristic measured by the auxiliary sound receiver when the compressor is driven and a reference sound reception frequency characteristic stored in the storage means, and based on the comparison result, the refrigeration A determination means is provided to determine whether the system is in a functional abnormal state.

Further, the storage means stores a reference sound reception frequency characteristic by the auxiliary sound receiver when the refrigerant is normally supplied by the compressor, and the determination means stores the measured sound reception frequency characteristics by the auxiliary sound receiver when the compressor is operating. The frequency characteristic may be compared with a reference sound reception frequency characteristic stored in the storage means, and based on the comparison result, it may be determined that the refrigerant supplied from the compressor has leaked from the refrigeration system.

Further, the storage means stores a reference sound reception frequency characteristic by the auxiliary sound receiver when the heat exchange fan of the refrigeration system is normally driven, and the determination means stores the reference sound reception frequency characteristic by the auxiliary sound receiver when the heat exchange fan of the refrigeration system is driven normally. The measured sound reception frequency characteristic may be compared with a reference sound reception frequency characteristic stored in the storage means, and based on the comparison result, it may be determined that the fan is locked.

(Function) When the refrigeration system is operated by driving the compressor, a noise is generated due to the driving of the compressor. At this time, the sound from the compressor is converted into an electrical signal by the detection means, and the arithmetic unit operates the control sound generator based on a signal obtained by processing the electrical signal.

As a result, the sound from the compressor is canceled out by interference between this and the artificial sound output from the control sound generator. Furthermore, the silencing effect of such active control is monitored by an auxiliary sound receiver at predetermined intervals, and if the monitoring result is outside a predetermined tolerance range, the control means calculation coefficient of the device (acoustic transfer function)
is changed by a predetermined amount, and accordingly, the silencing effect by active control is changed in a direction that falls within the above-mentioned allowable range. Such operation of changing the calculation coefficients is performed until the monitoring result by the auxiliary sound receiver falls within the permissible range, thereby performing so-called adaptive control in which the silencing ability is always kept optimal during active control.

On the other hand, when an abnormality occurs in the function of a component of the refrigeration system, the frequency characteristics of the sound from the compressor change in accordance with the abnormality.

At this time, the determining means compares the sound reception frequency characteristic measured by the auxiliary sound receiver when the compressor is driven and the reference sound reception frequency characteristic stored in the storage means. Therefore, the reference sound reception frequency characteristic stored in the storage means is
Since this is the frequency characteristic of the sound received by the auxiliary sound receiver when the refrigeration system is not abnormal, the judgment means determines the frequency characteristic of the refrigeration system that has become abnormal based on the comparison result between the standard sound reception frequency characteristic and the measured sound reception frequency characteristic. Determine the components.

Further, according to the silencer for a cooling device according to the second aspect, when refrigerant leaks from the refrigeration system, the frequency characteristics of the sound from the compressor change with the leakage.

At this time, the determining means determines the measured sound receiving frequency characteristic by the auxiliary sound receiver when the compressor is driven, and compares the measured sound receiving frequency characteristic with a reference sound receiving frequency characteristic stored in the storage means. . Therefore, since the reference sound reception frequency characteristic stored in the storage means matches the sound reception frequency characteristic by the auxiliary sound receiver when the refrigerant is not leaking from the refrigerant passage, the judgment means It is possible to detect that the refrigerant has leaked from the refrigerant passage based on the comparison result between the sound reception frequency characteristic and the measured sound reception frequency characteristic.

Further, according to the silencer for a cooling device according to the third aspect, when the fan is in a locked state, heat exchange in the refrigeration system is not performed normally. Therefore, the balance between the suction side pressure and the discharge side pressure of the compressor changes, and the frequency characteristics of the sound from the compressor change accordingly. At this time, the determining means determines the measured sound receiving frequency characteristic by the auxiliary sound receiver when the compressor is driven, and compares the measured sound receiving frequency characteristic with a reference sound receiving frequency characteristic stored in the storage means. . Therefore, since the reference sound reception frequency characteristic stored in the storage means is the same as the sound reception frequency characteristic by the auxiliary sound receiver when the fan is normally driven, the determination means Based on the comparison result between the frequency characteristics and the measured sound reception frequency characteristics, it can be determined that the fan is in the locked state.

(Example) Hereinafter, an example in which the present invention is applied to a refrigerator will be described.

First, in FIG. 3 showing the overall configuration of a refrigerator, 1 is a refrigerator main body which is a cooling device main body, and inside this, from the top, there are freezer compartments 2. A refrigerator compartment 3 and a vegetable compartment 4 are provided. A refrigeration system is installed inside the refrigerator, and these components will be explained below. That is, 5 is a cooler disposed at the back of the freezer compartment 2, and 6 is a fan that directly supplies cold air generated by the cooler 5 to the freezer compartment 2 and the refrigerator compartment 3. 7 is a machine room formed at the lower part of the back side of the main storage unit l, and inside this is a rotary type compressor 8. A condenser vibrator 9 and a defrosting water evaporator 10 using so-called ceramic fins are housed. and,
When the compressor 8 is in the driving state, the refrigerant from the compressor 8 is supplied to the cooler 5 through a refrigerant passage (not shown) to cool it, and the fan 6 is driven to exchange heat between the cooler 5 and the inside of the refrigerator. It is supposed to be done.

Now, as shown in FIG. 4 (here, the illustration of the condenser pipe 9 and the defrosting water evaporator 10 is omitted), the two machine rooms 7 have a rectangular opening only on the back side. This opening portion is closed by a machine room cover 11. At this time, the machine room cover 11
The peripheral edge thereof is airtightly attached to the opening edge of the machine room 7, and an elongated rectangular heat dissipation opening 11a extending in the vertical direction is formed at the left edge in the figure. . That is, when the machine room cover 11 is attached, the machine room 7 is in a closed state leaving the heat radiation opening 11a. Note that the machine room cover 11 is heated. It is made of a material (for example, metal such as iron) that has excellent conductivity and high sound transmission loss.

Further, in FIG. 4, numeral 12 is a vibration sensor which is a detection means attached to the compressor 8, and is provided to convert the vibration sound of the compressor 8, which is a noise source, into an electric signal. Reference numeral 13 denotes a speaker serving as a control sound generator disposed in the machine room 7, and this is placed, for example, in a part of the back wall of the machine room 7 (corresponding to the bottom wall of the refrigerator body 1) near the heat radiation opening 11a. It is installed and supported in a buried manner.

Reference numeral 14 denotes a microphone serving as an auxiliary sound receiver provided in the heat dissipation opening 11a, which receives the noise from the compressor 8 and the sound from the speaker 13 and monitors the silencing effect of the speaker 13. It has become.

As shown in FIG.
It is operated by the control signal Pa processed by the arithmetic unit 16 in the control unit 5, and the above-mentioned processing of the electrical signal is performed based on the principle of silencing by active control as described below. It has become.

That is, to roughly explain the principle of silencing by active control with reference to FIG.
l. R1 is the vibration sound detected by the vibration sensor 12; R2 is the sound received by the microphone 14 provided in the heat radiation opening 11a, which is the control target point; and R2 is the vibration sound detected by the vibration sensor 12. The acoustic transfer function of Tll, T21
．． When T12°I22, the following equation holds true as a two-man power two-output system.

Therefore, the sound S2 that should be generated by the speaker 13 is obtained from the above equation as follows: Sl - (-Tl2・R1+T11・R2)/(TLI
・T22−TI2・T21) However, in this case, since the goal is to make the sound level at the heat radiation opening 11a zero, it can be set as R2-0. As a result, 82 introduction R1・T12/(, T12・T 21− T 1
1-T22). As can be understood from this equation, in order to reduce the sound R2 at the heat radiation opening 11a to zero,
The sound R1 received by the vibration sensor 12 is
) If the speaker 13 generates the processed sound S2 through a filter, the sound level at the heat dissipation opening 11a can theoretically be reduced to zero. It is configured to apply a control signal Pa to the speaker 13 while processing (computing) sound at high speed.

Now, in the above equation (1), FG, T12-Gso
, T21-Gas, Tl1-GsIIl,
When replaced with I22-Gao, G = Gso/ (Gso◆Gam -G5l111
1Gao) (2) Here, G so, G all, G ss
, G ao means that the first subscript corresponds to the input side and the second subscript corresponds to the output side (response side). For example, Gas
shows the acoustic transfer function when measured with the input signal to the speaker 13 as the input end and the output signal from the microphone 14 as the output side. If the configuration is such that the noise from the compressor 8 is detected by the vibration sensor 12, the vibration sensor 12 does not receive the sound from the speaker 13, so the Ga noise can be regarded as zero. Therefore, the above formula (2) is: G−−Gso/ (Gsi−Gao) −・−−
--(3). Here, G so/G sm −
Since G is 0, the above equation (3) is: G --G mo/ Gao ・・
・-(4). In other words, the sound level at the heat dissipation opening 11a can be theoretically determined by generating a sound from the speaker 13 that is processed by filtering the electric signal from the vibration sensor 12 according to G shown in equation (4) above. It can be set to zero at the top.

On the other hand, in the case of the refrigerator configured as described above, the noise level generated in the machine room 7 in response to the drive of the compressor 8 is in the band of about 700H2 or less and in the range of 1.5 to 5KHz, as shown in FIG. This state has the property of increasing in each band. Among the noise corresponding to each of these bands, the noise on the high frequency side can be attenuated by transmission loss in the machine room cover 11, etc., and can be easily attenuated by installing an appropriate sound absorbing member in the machine room 7. Since the noise can be muted, the vibration sensor 12° speaker 1 as described above is used.
3 and the active control of noise by the computing unit 16 is 700Hz.
The following should be used as the target frequency.

In addition, when performing active noise control as described above, it is important to configure the noise in the machine room 7 so that it becomes a one-dimensional plane traveling wave, both theoretically and technically. This is important for easy and accurate execution.

Therefore, in this embodiment, of the three-dimensional depth, width, and height dimensions W and H in the machine room 7 shown in FIG. Dimensions.

Set larger than H (specifically, W=600■, D=H
-200 mm), so that the standing wave of sound in the machine room 7 is established only in the primary mode. That is, for example, when the machine room 7 is assumed to be a rectangular cavity, the following equation holds true.

f -C-NX LX 10 (Ny Ly
10 (Nz/Lz)2/2 However, f is the resonant frequency (H
z), Nx, Ny.

Nz is the th mode in each direction of x, y, z, Lx, Ly, L
z is the dimension in each of the X, Y, and Z directions in the machine room 7 (that is,
W, H), C is the speed of sound. Therefore, from the above formula, x,
Frequencies fx, f of the first standing wave in each direction of y and z
y and fz can be found.

That is, as mentioned above, the depth dimension D-200111,
When the width dimension W is set to 600 mm and the height dimension H is set to 200 mm, the frequency fx of the first standing wave in the X direction is Ny = Nz = 0, and the sound speed C = 340 m.
/second, fx -340 (110,2) /2 = 850Hz, and similarly, the frequencies fy and fz of the first standing wave in the Y and Z directions are fy -340 (110,6) 2/2 =283Hz fz-340(110°2) 2/2 =850Hz. As a result, the target frequency (-700H
z) below, the standing wave of noise in the machine room 7 moves in the Y direction (
This is true only for the mode in the width direction), and the noise within the machine room 7 can be regarded as a one-dimensional plane traveling wave. Therefore, when silencing noise by active noise control using the speaker 13 or the like, theoretical handling of the wavefront becomes easy, and silencing control can be performed easily and accurately.

Now, in FIG. 1, the vibration signal So from the microphone 14 is input to the adaptive control circuit 17, which is a control means in the out-of-phase sound generation circuit 15, and is used for adaptive control. The principles of adaptive control are shown in Figures 8 to 1.
This will be explained with reference to FIG.

Here, the noise from the compressor 8 is S, and the vibration sensor 1 is
M is the vibration sound from 2, A is the sound from the speaker 13, and O is the acoustic signal from the microphone 14.

The acoustic transfer function from the compressor 8 to the vibration sensor 12 is G5111. Compressor 8 to microphone 14
Let G so be the transfer function from the speaker 13 to the microphone 14 , and Gao be the transfer function from the speaker 13 to the microphone 14 .

In FIG. 8, the speaker 13 receives a white noise signal from one white noise generator via the switch 18, so that when the switch 18 is on, the speaker 13 receives the same level of white noise signal in a predetermined frequency bandwidth. White noise with a power of is output. This switch 18 is set to be turned on at a predetermined timing when the compressor 8 is not driven. Further, the white noise signal from the white noise generator 19 is applied to the first adaptive filter 20. The first adaptive filter 20 controls the speaker 13 and the microphone 1 based on the difference between the white noise signal from the white noise generator 19 and the acoustic signal O from the microphone 14.
The acoustic transmission signal Gao between the four channels is measured.

On the other hand, the vibration sound signal M from the vibration sensor 12 is multiplied by the acoustic transfer function Gao obtained by the first adaptive filter 20, and then filtered to the second adaptive filter 20.
The signal is supplied to the filter 21. This second
The adaptive filter 21 has an acoustic transfer function Gao
Based on the difference between the vibration sound signal M-Gao from the vibration sensor 12 multiplied by Gao and the acoustic signal O from the microphone 14, the acoustic transfer function G for active control execution and the latest value obtained by this adaptive control are determined. The difference ΔG from the acoustic transfer function G new is determined as described below. In this case, the acoustic transfer function G is an initial setting value or a value previously determined by adaptive control. Also, the acoustic transfer function Ga.

is the value currently subtracted by the first adaptive filter 20.

Now, when considering the driving state of the compressor 8, M −
5-Gsi ・-= (5) 0-5
-Gso 10A-Gao --------(6)
It can be expressed as A-M・G (7). Furthermore, since the path from the vibration sensor 12 to the microphone 14 via the second adaptive filter 21 can be expressed as MeGao◆ΔG-0−...(8), the above equation (8) can be expanded. Then, ΔG-0/ (M-Gao) - (S-Gso+A ・Gao) / (M ・Gao
)=(S −Gso+M φ G −Gao
)/(M-Gao)=(S・Gso)/
(M-Gao) ten (MG-Gao)/(M-
Gao) = (S - Gso) / (S - G
si−Gao) +G= (Gso/Gsa+)
/ Gao ten G where G so/ G sm= G
Since it can be regarded as tro, it becomes ΔG − Gmo/ Gao + G. Now, if we consider the optimal acoustic transfer function to be G new, then -G so/G ao - G new, so ΔG=-Gnev+G, and G new -G-Δ
It can be expressed as G. Therefore, by changing the acoustic transfer function G to the acoustic transfer function G new and then performing active control based on the acoustic transfer function G new,
You can change the coefficient in real time to maintain the optimum muting volume.

Now, in order to actually operate the adaptive control system shown in FIG. 8, first, the switch 18 is turned on at a predetermined timing when the compressor 8 is in a non-driving state as shown in FIG. 9. Then, white noise at a predetermined level is output from the speaker 13 by the white noise signal from one white noise generator, so the first adaptive filter 20 generates a speaker that satisfies the acoustic transfer relational expression 0-A-Gao. An acoustic transfer function Gao between the microphone 13 and the microphone 14 is determined.

Then, when the compressor 8 is driven, the second adaptive filter 21 determines ΔG based on Gao determined by the first adaptive filter 20, as shown in FIG. Thereby, based on ΔG determined by the second adaptive filter 21, G n
ew is determined and active control is performed based on the c new.

On the other hand, as shown in FIG. 1, the anti-phase sound generation circuit 15 is
It receives a drive command for the compressor 8 (hereinafter referred to as a combination on signal Sa).

Therefore, the electric circuit for outputting the above-mentioned combination signal Sa is a circuit originally included in the refrigerator, and
During the output period of the combination-on signal Sa, the compressor 8
and a fan 6 are driven, and circuits related to these will be briefly explained based on FIG. 1. In other words, the thermistor 2 connected in series with the resistor 22
3 is provided to detect the temperature of the freezing compartment 2 (see FIG. 3), and the thermistor 23 outputs a temperature signal sb indicating the temperature of the freezing compartment 2.

Further, in the comparator 24, the temperature signal sb from the thermistor 23 is compared with the reference voltage VC output from the common connection point of the resistor 25.26, and when the signal level of the temperature signal sb exceeds the reference voltage VC, The comparator 20 outputs a high-level combination signal Sa. With the above configuration, when the temperature of the freezer compartment 2 rises to a predetermined temperature, the comparator 24 outputs the combo-on signal Sa in response to the signal level of the temperature signal sb from the thermistor 23 exceeding the reference voltage Vc. The combination ON signal Sa from the comparator 24 is applied via an AND circuit 27 to the base of a transistor 29 for driving the relay 28.

Further, the relay coil 28a of the relay 28 is connected so as to be excited when the two transistors are on, and when the relay switch 28b of the relay 28 is turned on in the excited state, the compressor 8 and the fan 6 are activated by the commercial AC power supply. 30 to drive these.

On the other hand, the judgment means 31 of the out-of-phase sound generation circuit 15 determines the input status of the combination-on signal Sa, the acoustic analysis result by a built-in spectrum analyzer (not shown), and the reference received sound frequency characteristic stored in advance in the storage means 32. Based on this, it is determined whether the refrigerant has leaked from the refrigerant passage. That is, the determining means 31 inputs the electric signal So from the microphone 14 and measures the received sound frequency characteristic of the electric signal using a spectrum analyzer, and also stores the measured received sound frequency characteristic and the storage means 32 in advance. It is compared with the reference sound reception frequency characteristic, and if there is a predetermined difference between the two, it is determined that the refrigerant has leaked. In this case, the reference sound reception frequency characteristic stored in the storage means 32 is the one that the microphone 14 has when the compressor 8 is driven and the refrigerant is normally supplied without leaking from the refrigerant passage.
The frequency characteristics (see FIG. 8) of the electrical signals from the 3D are measured in advance, and specifically, the sound level for each frequency band (1/3 octave) is stored in the storage means 32. When the refrigerant leaks from the refrigerant passage, the determining means 31 causes the speaker 13 to appropriately output a notification signal pb based on the leakage, and also outputs a low-level regulation signal Sc to the AND circuit 27. Here, when the notification signal pb is output from the determining means 31, a notification sound such as "beep" is emitted from the speaker 13, and when the low level regulation signal Sc is output, the combination ON signal Sa is output from the AND circuit 27. It is regulated to pass through.

Therefore, in the following, the functions of the anti-phase sound generation circuit 15, that is, the functions of the arithmetic unit 16. Adaptive control circuit 17 and judgment means 3
Each function of 1 will be explained with reference to the flowchart of FIG. That is, as the temperature of the freezing compartment 2 rises, the signal level of the temperature signal sb from the thermistor 23 or the reference voltage V
When the value exceeds c, the comparator 24 outputs a combination-on signal Sa via the AND circuit 27, and the compressor 8 is driven accordingly. At this time, the determining means 31 waits until the manual timing of the combination on signal Sa in step A, so when the drive start timing of the compressor 8 comes, it judges again whether or not the combination on signal Sa is input and then ( Step B), Microphone 1
4, the received acoustic signal is sampled (step C), and the acoustic signal is analyzed by a spectrum analyzer (step D). Then, it is determined whether or not there is a difference between the measured sound reception frequency characteristic obtained by the spectrum analyzer and the reference sound reception frequency characteristic stored in the storage means 32 by a method described later (step E).

At this time, if the function of the compressor 8 forming a part of the refrigerant passage is normal, refrigerant is supplied from the compressor 8 to the cooler 5 through the refrigerant passage. Here, when such refrigerant supply is performed normally, the acoustic signal analysis result in step D is the same as the frequency characteristic shown in FIG. Therefore, the determining means 31 determines rNOJ in step E, and in this case, the computing unit 16 processes the acoustic signal sampled from the microphone 14 based on the acoustic transfer function described above (step F). ), and outputs a control signal Pa based on the processing (step G). As a result, the control signal Pa is given from the arithmetic unit 16 to the speaker 13, and the control sound is emitted from the speaker 13 in response to the control signal Pa, so that the noise accompanying the drive of the compressor 8 and the control sound from the speaker 13 are heat dissipated. Active control is performed in which the sound level is lowered by interference with each other in the opening 11a.

At this time, the adaptive control circuit 17 samples the electrical signal So from the microphone 14 (step H) and monitors the silencing effect due to the above-described active control. and,
If the monitoring result is within a predetermined allowable range, the process returns from step I to step B.

The arithmetic unit 16 forms a loop that repeatedly executes the routine from step B to step I while the combination ON signal Sa is input manually.

As a result, a control signal Pa corresponding to the noise accompanying the drive of the compressor 8 is output to the speaker 13, and active control is performed in real time, so even if the acoustic component from the compressor 8 fluctuates, The noise can be attenuated by following the fluctuations.

However, if the result of monitoring for the silencing effect is outside the allowable range, the adaptive control circuit 17 moves from step I to step J and changes the calculation coefficient (transfer function) in the calculator 16 in a direction that increases the silencing effect. As a result, the output from the speaker 13 is adjusted, and the silencing effect of the artificial sound from the speaker 13 is changed to fall within the above-mentioned allowable range. After this, a loop is formed to repeatedly execute steps B-J, and the operation of changing the calculation coefficients of the calculation unit 16 described above is repeated.

Now, due to functional deterioration of the compressor 8 due to long-term operation, the refrigerant compressed by the compressor 8 may leak. In such a case, the compressor 8 will not be able to sufficiently supply refrigerant to the cooler 5, leading to an increase in the temperature inside the refrigerator. Therefore, the reverse phase sound generation circuit 15 detects the leakage of refrigerant from the compressor 8 and takes appropriate measures in the following manner.

In other words, when refrigerant is leaking from the compressor 8, the frequency characteristics of the noise accompanying the drive of the compressor 8 change as the refrigerant leaks, so by detecting this, the refrigerant leak state can be detected. It is possible. Here, the frequency characteristics of the noise (sound received by the microphone 14) accompanying the drive of the compressor 8 when the refrigerant leaks are shown in FIG. Now, when comparing the measured sound reception frequency characteristics shown in Fig. 12 with the reference sound reception frequency characteristics shown in Fig. 11 when there is no refrigerant leak, it is found that the frequency band of 500 Hz or more when there is a refrigerant leak is the same as when there is no leak. It can be seen that it is higher compared to This is because the lubricating oil in the compressor 8 becomes insufficient as the refrigerant leaks from the compressor 8, increasing the frictional force of the mechanical parts that make up the compressor, or when the refrigerant gas leaks, the lubricating oil in the compressor 8 becomes insufficient. The pressure contact force of the refrigerant compression blades decreases, causing chattering.
It is presumed that this will affect the pulsation of the refrigerant discharged from the compressor 8. This means that among the frequency characteristics of the noise accompanying the drive of the compressor 8, from 500Hz to 2K
The band up to Hz is consistent with the fact that the main component is the pulsating sound of the refrigerant circulating in the refrigeration cycle. Furthermore, among the frequency characteristics of the noise of the compressor 8, 500Hz
In the following bands, the main component is the noise emitted from the compressor 8 itself when the compressor 8 is driven.
In particular, it is affected by the rotational speed of the compressor 8 and frequency characteristics that are integral multiples of the power supply frequency. Also, compressor 8
The noise propagated to the refrigerator's component parts such as the cabinet, compressor stand, evaporation plate pedestal, piping, etc. and emitted as secondary sound from these also affects the frequency band below 500 Hz. On the other hand, the noise of the compressor 8 in a frequency band of 2 KHz or higher is mainly due to the sliding noise of the mechanical parts of the compressor 8.

Therefore, in step E, the determining means 31
As mentioned above, if a predetermined difference is found between the measured sound reception frequency characteristic based on the sound reception signal by the microphone 14 and the reference sound reception frequency characteristic stored in the storage means 32, "YESJ" is determined.
Based on this determination, the process proceeds to step K, where the output of the control signal Pa is stopped, and active control for noise is accordingly stopped.

Next, the determining means 31 outputs the notification signal pb (step L), waits until 30 minutes have elapsed (step M), and then stops outputting the notification signal pb (step N).
). As a result, a 30-minute alarm will be emitted from the speaker 13, so people around the refrigerator will be able to recognize that there has been a refrigerant leak and take out the food stored inside the refrigerator to quickly respond to the abnormal situation. I can deal with it. Incidentally, it is preferable that the time period during which the alarm is emitted from the speaker 13 is about 30 minutes to one hour, so that the alarm can be reliably called to the attention of surrounding people.

Subsequently, the determining means 31 outputs the regulation signal Sc at a low level in step O. As a result, the comparator 24
Since the passage of the combination ON signal Sa from the AND circuit 27 is restricted, the transistor 29, which had been on until then, is turned off, and the relay switch 28b is accordingly turned off. Then, since the compressor 8 is disconnected from the AC power supply 30, even if all the refrigerant leaks from the refrigerant passage, the compressor 8 will not continue to be driven for a long time.

In this case, if the temperature of the freezer compartment 2 has fallen sufficiently and the combination ON signal Sa is not output from the comparator 24, the process moves from step B to step P, whereby the arithmetic unit 16 is controlled. Since the output of the a signal Pa is stopped,
Even if the drive of the compressor 8 is intermittent based on the temperature of the freezer compartment 2, only silencing control is performed when the driving is stopped, so meaningless silencing control can be avoided.

In summary, the out-of-phase sound generation circuit 15 is configured to include a determining means 31 that detects a refrigerant leak state based on the noise received by the microphone 14 and notifies the user of the leak state using the speaker 13. Therefore, a new function of detecting a refrigerant leak state using the microphone 14 and speaker 13 provided for adaptive control can be easily added. Therefore, there is no need to separately provide a circuit and judgment means for detecting the refrigerant leak state and notifying the leak state.
It is possible to prevent the overall configuration from becoming complicated while adding new functions.

Note that the present invention may be configured to be applied to detecting a locked state of the fan 6 instead of detecting a refrigerant leak. That is, the frequency characteristic (see FIG. 13) of the electric signal from the microphone 14 when the compressor 8 and fan 6 are driven simultaneously is stored in the storage means 31 as the reference sound reception frequency characteristic.

Now, if the fan 6 breaks down after being driven for a long period of time, or if there is an assembly error in the fan 6, the fan 6 may become locked and not operate even though it is energized. be.

In such a case, heat exchange in the refrigeration system by the fan 6 is not performed sufficiently, resulting in an unexpected rise in temperature inside the refrigerator. However, when the fan 6 is in the locked state, heat exchange is insufficient, so the pressure on the discharge side (connection port with the delivery tube) of the compressor 8 and the suction side (
The balance between the pressure and the pressure at the suction pipe (connection port) is disrupted.

As a result, the frequency characteristics of the noise accompanying the drive of the compressor 8 are changed.
4 (see FIG. 14) and outputs the notification signal pb and the regulation signal SC based on the comparison result. Therefore, by checking the notification sound from the speaker 13, it can be determined that the refrigerant has leaked from the refrigeration cycle.

Here, when comparing the measured sound reception frequency characteristics shown in FIG. 13 with the reference sound reception frequency characteristics shown in FIG. It can be seen that the value is higher than that in the unlocked state of No. 6. This is presumed to be due to an increase in the compression ratio for the refrigerant as the pressure on the suction side of the compressor 8 decreases due to insufficient evaporation of the refrigerant due to insufficient heat exchange in the cooler 5. This is consistent with the fact that the band from 500 Hz to 2 KHz of the frequency characteristics of the noise accompanying the drive of the compressor 8 is mainly composed of the pulsating sound of the refrigerant circulating in the refrigeration cycle.

Of course, in each of the above embodiments, although the machine room 7 is configured to perform noise reduction control, since the machine room 7 is communicated with the outside through the heat dissipation opening 11a, the heat generated when the compressor 8 is driven causes damage inside the machine room 7. The temperature will not rise abnormally. In addition, since the machine room cover 11 is made of a material with excellent thermal conductivity, the heat dissipation efficiency of the heat generated in the machine room 7 is improved, and from this aspect as well, the temperature inside the machine room 7 increases. can be kept low.

In each of the above embodiments, the measured sound reception frequency characteristics and the reference sound reception frequency characteristics were compared by comparing frequency bands every 1/3 octave. It is also possible to compare only the bands.

Alternatively, the comparison may be made based on the integrated difference in signal level in a specific frequency band or the difference in signal level in the entire frequency band.

Furthermore, the waveform pattern of the sound signal received by the microphone 12,
Alternatively, the comparison may be performed using a combination of the above comparison methods.

Further, in each of the above embodiments, the noise from the compressor 8 is detected by the vibration sensor 12 serving as the detection means, but instead of this, the noise from the compressor 8 may be detected by, for example, a microphone.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings. For example, the outdoor unit of an air conditioner or a refrigerated showcase may be applied as a cooling device to be silenced. Various modifications can be made without departing from the scope.

[Effects of the Invention] According to the present invention, as is clear from the above description, the noise associated with the compressor drive is actively canceled, and the active control conditions associated with the compressor drive are adjusted based on the sound reception result by the auxiliary sound receiver. The auxiliary sound receiver can also be used to detect malfunctions in the components of the refrigeration system that are the cause of abnormal operation of the compressor. This has the excellent effect of increasing the added value of the tableware.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic electrical configuration diagram, FIG. 2 is a flowchart showing the control contents of the out-of-phase sound generation circuit, and FIG. 3 is a vertical cross-section of the refrigerator. 4 is a perspective view showing the main parts in an exploded state, FIG. 5 is a schematic configuration diagram showing the principle of silencing by active control, FIG. Figure 7 is a noise level characteristic diagram, Figure 8 is a block diagram schematically showing the principle of adaptive control, and Figures 9 and 10 are diagrams showing the operation of adaptive control.
Fig. 11 is a sound frequency characteristic diagram when there is no refrigerant leak, Fig. 12 is a sound reception frequency characteristic diagram when there is no refrigerant leak, and Fig. 13 is a sound reception frequency characteristic diagram when the fan is not locked. , FIG. 14 is a diagram corresponding to FIG. 13 when the fan is locked. In the figure, 1 is the refrigerator body, 7 is the machine room, 8 is the compressor,
10 is a defrosting water evaporation device, 11 is a machine room power/(-118 is an opening for heat radiation, 12 is a vibration sensor (detection means), 13 is a speaker (a sound generator for control), and 15 is a circuit for generating negative phase sound. ,
16 is a computing unit, 17 is an adaptive control circuit (control means), 31
is a judgment means, and 32 is a storage means.

Claims (1)

[Scope of Claims] 1. A refrigeration system comprising components such as a compressor housed in a machine room and a cooler that is cooled as the compressor is driven, the system comprising: The sound emitted from the machine room to the outside is controlled by converting the sound generated by the machine into an electrical signal using the detection means, and by operating the control sound generator based on the signal processed by the processing unit. In a silencing device for a cooling device that actively cancels out noise, an auxiliary sound receiver is provided for monitoring the silencing effect of the control sound generator at predetermined intervals, and a monitoring result by the auxiliary sound receiver is monitored at a predetermined time. a control means for changing the calculation coefficient of the arithmetic unit by a predetermined amount when the result is outside the permissible range, and for performing the changing operation until the monitored result falls within the permissible range; a storage means for storing a reference sound reception frequency characteristic by the auxiliary sound receiver when the compressor is in operation, and a sound reception frequency characteristic measured by the auxiliary sound receiver when the compressor is driven and a reference sound reception frequency stored in the storage means; A silencing device for a cooling device, comprising: determining means for comparing characteristics and determining a functional abnormal state in the refrigeration system based on the comparison result. 2. The storage means stores the reference sound reception frequency characteristics by the auxiliary sound receiver when the compressor is normally supplying refrigerant, and the judgment means stores the measured sound reception frequency characteristics by the auxiliary sound receiver when the compressor is operating. The frequency characteristic is compared with the reference sound reception frequency characteristic stored in the storage means, and based on the comparison result, it is determined that the refrigerant supplied from the compressor has leaked from the refrigeration system. A silencing device for a cooling device according to claim 1. 3. The storage means stores the reference sound reception frequency characteristics by the auxiliary sound receiver when the heat exchange fan of the refrigeration system is normally driven, and the determination means stores the reference sound reception frequency characteristics by the auxiliary sound receiver when the compressor is driven. A claim characterized in that the measured sound reception frequency characteristic is compared with a reference sound reception frequency characteristic stored in the storage means, and it is determined that the fan is locked based on the comparison result. Item 1. A silencer for a cooling device according to item 1.