JPH03264792A - Silencer for cooling device - Google Patents

Abstract

PURPOSE:To increase an added value by forming an auxiliary sound receiver usable also for detecting a constitutional element placed in an abnormal function, in the case of a silencer provided with a silencing function for suitably changing an active control condition according to driving a compressor being based on a sound-receiving result by the auxiliary sound receiver. CONSTITUTION:In a silencer for actively negating a noise from inside a machine chamber 7 formed in a refrigerator or the like, a speaker (controlling sound device) 13, actuated by a control signal in which an electric signal of a vibration sensor 12 mounted to a compressor 8 is processed by an arithmetic device 16 in a reverse phase sound generating circuit 15, is arranged in the machine chamber 7. An active control condition is suitably changed by an output signal of a microphone (auxiliary sound receiver) 14 by providing it in a heat radiating opening part 11a of the machine chamber 7. A constitutional element, placed in an abnormal function, is judged by reading the reference sound receiving frequency characteristic, when abnormality is generated in a plurality of functions of the refrigerating system constitutional element, from a memory means 31 to be compared with the measured sound receiving frequency characteristic by a judging means 30.

Description

[Detailed Description of the Invention] [Object 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 the refrigerator is noise from the machine room in which the compressor and the piping system connected thereto are housed. In other words, in the machine room, the compressor itself generates relatively loud noises (combu!/tsusa motor operating noise, fluid noise due to compressed gas, mechanical noise from movable mechanical elements of the compression mechanism, etc.), and the The piping system also generates noise due to its vibration, 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 entire refrigerator.

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
Sound absorbing members and sound insulating members are arranged around the compressor and the piping system 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 dissipation because it is necessary to release the heat generated by the compressor to the outside, and noise leaks to the outside from these openings. I'm going to go out. For this reason, the conventional noise reduction measures as described above naturally have their limits, 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 an auxiliary sound receiver (for example, a microphone) installed at a specific position, and then converts the sound from the noise source into an electrical signal by processing the electrical signal using a computing device. By operating a control sound generator (for example, a speaker) based on this, the sound generator emits an artificial sound 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. The idea is to attenuate the original sound by causing this artificial sound to interfere with the original sound.

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 arithmetic unit 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.

[Configuration of the Invention (Means for Solving the Problems)] In order to achieve the above 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 silencing device for a cooling device, a sound damping device for a cooling device is provided with a control sound generator that generates an artificial sound using a signal processed by a computer from the above-mentioned electric/non-electronic signal, and the sound from a compressor is actively canceled by interference with the above-mentioned artificial sound. ,
An auxiliary sound receiver is provided to monitor the silencing effect of the control sound generator at predetermined intervals, and if the monitoring result 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 refrigeration system by a predetermined amount and to perform the changing operation until the monitored result falls within the allowable range, and an abnormality occurs in one or more functions of the components of the refrigeration system while the compressor is being driven. A storage means is provided for storing a reference sound reception frequency characteristic by the auxiliary sound receiver when the compressor is driven for a predetermined time or more, and the measured sound reception frequency characteristic by the auxiliary sound receiver is stored in the storage means. and determining means for comparing the received sound frequency characteristic with a standard received sound frequency characteristic and determining the component in the refrigeration system that has malfunctioned based on the comparison result.

(Operation) When the refrigeration system is operated by the drive of the compressor, noise is generated due to the drive 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, if an abnormality occurs in the function of a component of the refrigeration system, the operating time of the compressor may become abnormally long due to the abnormal function. At this time, the determining means measures the drive time of the compressor, and if the drive time exceeds a predetermined time, it determines the measured sound reception frequency characteristic by the auxiliary sound receiver when the compressor is running, and also determines the measured sound reception frequency. The characteristics are compared with the reference sound reception frequency characteristics stored in the storage means. Therefore, since the reference sound reception frequency characteristics stored in the storage means match the sound reception frequency characteristics by the auxiliary sound receiver when various abnormalities occur in the functions of the components of the refrigeration system, the judgment means can determine which component in the refrigeration system has malfunctioned based on the comparison result between the reference sound reception frequency characteristic and the measured sound reception frequency characteristic.

(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 provided inside the refrigerator, and these components will be explained. 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 refrigerator body 1, 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 lO is omitted), the machine room 7 has a rectangular opening only on its 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 11g 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. The machine room cover 11 is made of a material (for example, metal such as iron) that has excellent thermal 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 device 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 dissipation opening lla. 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.
2. R1 is the vibration sound detected by the vibration sensor 12, R2 is the sound received by the microphone 14 provided in the heat dissipation opening 11a, which is the point to be controlled, and further between the output and input points of the sound as described above. The acoustic transfer function of T11. T
21. When T is 12°T22, the following equation holds true as a two-man power two-output system.

Therefore, the sound s2 to be generated by the speaker 13 is calculated from the above equation as follows: S2- (-T12・R1+T11・R2)/(Tll
・T22-712・T21), but
In this case, since the goal is to reduce the sound level at the heat radiation opening 11a to zero, it can be set to R2-0. As a result, S2-R1-TI2/ (T12・T21-Tll・T
22). As can be understood from this equation, in order to reduce the sound R2 at the heat dissipation opening 11a to zero, the sound R1 received by the vibration sensor 12 is given by F-T12/(T12・T21−T11・T22
)... (1) If the processed sound S2 is generated from the speaker 13 through a filter, the sound level at the heat dissipation opening 11a can theoretically be reduced to zero. The computing unit 16 is configured to provide a control signal Pa to the speaker 13 while performing such sound processing (computation) at high speed.

Now, in the above equation (1), F deception C;, Tl2-G
so, T21-Gas, T11=Gsi,
When replaced with T22-Gao, G = Gso/ (Gso@Gai - GsmaGa
o)...(2) It becomes. Here, G so, G am, G sm,
The meaning of G ao is that the subscript in the first stage corresponds to the input side, and the subscript in the second stage corresponds to the output side (response side). It shows the acoustic transfer function when measured with a signal on the output side. Therefore, when 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 Gram can be regarded as zero. Therefore, the above formula (2) is: G −−Gso/ (Gsm−Gao) −・・
...(3). Here, G so/ G sm
-G gla, the above formula (3) is: G - - GIIo/Gao - (4)
becomes. In other words, the sound level at the heat dissipation opening 11g can be calculated theoretically 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 according to the drive of the compressor 8 is as shown in FIG. It becomes a state in which it 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, among the three-dimensional depth, width, and height dimensions W and H in the machine room 7 shown in FIG. Dimensions.

Set higher than H (specifically, W-600am, D-
H-20C1+ti) so that the standing wave of sound within 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 +(Ny Ly +(Nz
Lz)2/2, where f is the resonance frequency (Hz), N
X, 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, y
, z Frequencies of the first standing wave for each direction fx, fy
, fz can be obtained.

That is, as mentioned above, when the depth dimension D-200mm, the width dimension W-600mm, and the height dimension H-200+a+a are set, the frequency fx of the first standing wave in the X direction is Ny -Nz-0, speed of sound C-340m/
As a second, fx = 340 (110,2)''/2850Hz, and similarly, the frequency of the first standing wave in the Y and Z directions is fy -340 (110,6) 2/2 = 283Hz fzm340 (110,2) 2/2850Hz.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 electrical 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
2, the sound from the speaker 13 is A, and the acoustic signal from the microphone 14 is 0°.The acoustic transfer function from the compressor 8 to the vibration sensor 12 is Gs (the transfer function from the compressor 8 to the microphone 14 is Let Gso be the transfer function from the speaker 13 to the microphone 14, and Gao.

In FIG. 8, the speaker 13 receives a white noise signal from a white noise generator 19 via a switch 18, so that when the switch 18 is on, the speaker 13 receives a white noise signal with a predetermined frequency bandwidth of the same degree. White noise exhibiting power 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 Z with the acoustic transfer function Gao determined by the first adaptive filter 20 and then given to the second adaptive filter 21. . This second adaptive filter 21 has an acoustic transfer function Ga
Based on the difference between the vibration sound signal M''GaO from the vibration sensor 12 multiplied by GaO by o 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 acoustic transfer function G new
The difference ΔG between ΔG and ΔG 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=S
-Gs* ・・・・・・(5)0-
5-Gso+A-Gao (6)
A bird M-G ・・・・・・(7)
It can be expressed as. Further, the vibration sensor 12 is connected to the microphone 14 via the second adaptive filter 21.
The path leading to M-Gao ΔG-0-...-(8) can be expressed as ΔG-0/(M-Gao)-(S-Gso+A- Gao)/(M-Gao)wR(
SLIGSO+MφG#Ga0)/〈M-Gao)-(
S LIGso) / (M #Gao)+ (M
-G -G ao) / (M -G ao) - (S-
Gso)/(S-GsII-Gao) 10G= (Gso
/ Gsti) / Gao+ G here, G so/
Since it can be considered as G sm - G so, ΔG = G so/G ao+ G. Now,
If we consider the optimal acoustic transfer function to be G new, -G g
Since o/G ao -G new, ΔG=-G
nev ten G, which can be expressed as Gney - G - ΔG. Therefore, the acoustic transfer function C is the acoustic transfer function G n
By performing active control based on the acoustic transfer function G new after changing to ew, the coefficient can be changed in real time and the amount of silencing can be maintained at an optimum level.

Now, in order to actually operate the adaptive control system shown in FIG. 8, first, as shown in FIG. 9, the switch 18 is turned on at a predetermined timing when the compressor 8 is in a non-driving state. Then, a white noise signal of a predetermined level is output from the speaker 3 by the white noise signal from the white noise generator 19, so that the first adaptive filter 20 outputs white noise from the speaker 3 that satisfies the acoustic transfer relational expression 0-A-Gao. and the acoustic transfer function Gao between the microphone 14 is determined.

When the compressor 8 is driven, the second adaptive filter 21 determines ΔG based on Gao determined by the first adaptive filter 2o, 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 G new.

On the other hand, as shown in FIG. 1, the out-of-phase sound generation circuit 14 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 freezer compartment 2 (
(See FIG. 3), 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 Ve 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 24 outputs a high-level combination-on 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 to the base of a transistor 28 for driving the relay 27. The relay coil 27a of the relay 27 is connected to be excited when the transistor 28 is on, and when the relay switch 27b of the relay 27 is turned on in the excited state, the compressor 8 and the fan 6 are connected to the commercial AC power source. 29 to drive these.

On the other hand, the combination-on signal Sa and the electric signal So from the microphone 14 are determined by the determination means 3 of the reverse phase sound generation circuit 15.
0 is now being manually operated.

This judgment means 30 is based on the human power status of the combo-on signal Sa and the electric signal So, the timing operation of the built-in timer, the built-in spectrum analyzer (none of which is shown), and the reference received sound frequency characteristics stored in advance in the storage means 31. Based on this, it is determined whether there is a malfunction occurring in a component of the refrigeration system, such as a failure of the thermistor 23, a locked state of the fan 6 (not operating even though it is energized), or a leak of refrigerant from the refrigerant passage. . In other words, the determining means 30
The electric signal So from the microphone 14 is manually measured and the sound reception frequency characteristic of the electric signal So is measured by a spectrum analyzer, and the measured sound reception frequency characteristic is compared with the reference sound reception frequency characteristic stored in advance in the storage means 31. If there is a predetermined difference between the two, it is determined based on the difference that an abnormality has occurred in a component in the refrigeration system. In this case, the reference sound receiving frequency characteristic stored in the storage means 31 refers to the microphone when the compressor 8 is in the driving state and the fan 6 is not locked, and when the compressor 8 is in the driving state and the function is normal such as no refrigerant leakage. 1
4 (Fig. 11 and 1, respectively)
3), and specifically, the sound level for each frequency band (every ⅓ octave) is stored in advance in the storage means 31. and,
When determining that an abnormality has occurred in any of the components of the refrigeration system, the determining means 30 outputs notification signals Pb, Pc, and Pd to the speaker 13 as appropriate based on the determination. Here, when the notification signal pb is output, the speaker 1
For example, a notification sound (continuous sound) such as "bee" is emitted from 3, and when the notification signal Pc is output, a notification sound (intermittent short sound) "pi, pip" is emitted, and the notification signal Pd When this is output, a notification sound (intermittent long sound) "Beep, Beep" is emitted.

Therefore, in the following, the negative phase sound generation circuit 15, that is, the arithmetic unit 16. The operation of the adaptive control circuit 171 determining means 30 will be explained with reference to the flowchart of FIG.

That is, when the temperature inside the refrigerator rises and the signal level of the temperature signal sb from the thermistor 23 exceeds the reference voltage Vc, the comparator 24 outputs the combination ON signal Sa, and in response, the compressor 8 starts to be driven. Ru. At this time, since the determining means 30 waits until the manual timing of the combination on signal Sa in step A, the compressor 8
When the drive start timing arrives, the timer is reset (step B) and the timer is started (step C).

At this time, if the functions of the thermistor 23 and the fan 6 are normal and the refrigerant is not leaking from the refrigerant passage, the inside of the refrigerator is cooled by the drive of the compressor 8, and the thermistor 2
The signal level of the temperature signal sb from 3 decreases. Then, when the time measured by the timer is within 3 hours, the determining means 30 moves from step D to step E and determines whether or not the combination on signal Sa is input. When the combination-on signal Sa is input manually, the calculator 16
Sampling the electrical signal SI from the vibration sensor 12 (
In step F), the electric signal S is processed based on the acoustic transfer function G described above (step G), and then a control signal Pa based on the processing is outputted (step H). 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 I) 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 J to step D.

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

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 monitoring result of the silencing effect is outside the allowable range, the adaptive control circuit 17 moves from step J to step K 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] 3 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 DK, and the operation of changing the calculation coefficients of the calculation unit 16 described above is repeated.

Now, during normal operation of the refrigeration system configured as described above, when the room temperature is, for example, 35°C or higher, when there is a power supply voltage mismatch, or when the
The compressor 8 is never in continuous operation for more than 3 hours. Other than this case, the causes of the compressor 8 being in continuous operation include: ■ The operation is set to high, ■ A defective temperature sensor, ■ The internal fan motor is locked, or the internal fan motor does not operate. Possible causes include the door being left ajar, ■ the door being left ajar, ■ refrigerant leaking from the refrigeration system, and ■ excessive injection of refrigerant into the refrigeration system.

Now, for example, if an abnormality occurs in the function of the thermistor 23, the temperature signal sb from the thermistor 23 will be The signal level may not fall below the reference voltage Vc for a long time, and in such a case, there is a risk that the cooling operation will be performed excessively and the interior of the refrigerator will be overcooled. Furthermore, if the fan 6 is locked, even though the function of the thermistor 23 is normal and refrigerant is being normally supplied to the cooler 5, heat exchange by the fan 6 is not performed and the inside of the refrigerator is insufficient. A problem occurs when the unit is not cooled down. Furthermore, if refrigerant is leaking from the refrigerant passage, even though the thermistor 23 and fan 6 are functioning normally, the refrigerant supply to the cooler 5 will be insufficient and the interior of the refrigerator will not be sufficiently cooled. The temperature inside the eggplant will rise.

Therefore, the determining means 30 detects abnormalities in the components of the refrigeration system and takes appropriate measures as follows.

In other words, if an abnormality occurs in the function of the thermistor 23 or the fan 6 as described above, or if refrigerant leaks from the refrigerant passage, it is assumed that the inside of the refrigerator is not sufficiently cooled, and the temperature signal sb from the thermistor 23 is The signal level remains above the reference voltage VC for a long time.

Therefore, the determining means 30 determines "No" when the time measured by the timer reaches 3 hours in step D, and proceeds to step L to analyze the acoustic signal. In other words, if the fan 6 malfunctions or refrigerant leaks from the refrigerant passage, the frequency characteristics of the noise caused by the drive of the compressor 8 will change depending on the cause, so by analyzing the frequency characteristics, it is possible to determine whether the compressor 8 has a long life. Determine what is driving it over time. here,
12 and 14 show the measurement results of the frequency characteristics of the noise (sound received by the microphone 14) accompanying the drive of the compressor 8 when the fan 6 is locked or when the refrigerant leaks.
It is shown in detail in the figure.

Now, when comparing the measured frequency characteristic shown in FIG. 12 with the reference frequency characteristic when the fan 6 is normally driven as shown in FIG.
It can be seen that the sound level in the frequency band from 00 Hz to 2.5 KHz is higher than when the fan 6 is in the unlocked state.

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 means that the band from 500Hz to 2KHz of the frequency characteristics of the noise accompanying the drive of the compressor 8 is
This is consistent with the fact that the main component is the pulsating sound of the refrigerant.

Furthermore, when comparing the measured frequency characteristics shown in Fig. 14 with the reference sound reception frequency characteristics shown in Fig. 13 when there is no refrigerant leak, it is found that 500 Hz at the time of refrigerant leak.
It can be seen that the above frequency bands are higher than when there is no leakage. 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. It is presumed that the contact force of the blades for compressing the refrigerant decreases and chattering occurs, thereby affecting the pulsation of the refrigerant discharged from the compressor 8. This means that 500H of the frequency characteristics of the noise accompanying the drive of the compressor 8
The band from z to 2 KHz is consistent with the fact that the main component is the pulsating sound of the refrigerant circulating in the refrigeration cycle. In addition, in the frequency characteristic of the noise of the compressor 8, the band below 500 Hz is mainly composed of the noise emitted from the internal body of the compressor 8 when the compressor 8 is driven, and in particular, the frequency characteristic of the rotation speed of the compressor 8 and the integer of the power supply frequency are It is affected by twice the frequency characteristics. In addition, the noise from the compressor 8 propagates to the component parts of the refrigerator such as the cabinet, compressor stand, evaporating dish stand, piping, etc., and the noise emitted from these as secondary sound is also 500H2.
The following frequency bands are affected. On the other hand, the main component of the noise of the compressor 8 in a frequency band of 2 KHz or higher is the noise caused by the sliding noise of the mechanical parts of the compressor 8.

Therefore, when the determination means 30 determines that an abnormality has occurred in the fan 6 by comparing the measured sound reception frequency characteristic and each reference sound reception frequency characteristic stored in the storage means 31 in step M, the determination means 30 performs step M. N, and outputs the notification signal pb. Then, the speaker 13 emits a beeping sound, so people around the refrigerator can recognize that the fan 6 is locked by hearing the warning sound. Therefore, even if an abnormal situation occurs in which the inside of the refrigerator is not sufficiently cooled due to the fan 6 exhibiting a locked state, it is possible to quickly deal with the problem and prevent the food in the refrigerator from spoiling. can.

Further, when the determining means 30 determines that the fan 6 is not locked in step M, the process proceeds to step O, and the measured sound receiving frequency characteristic and the reference sound receiving frequency characteristic stored in the storage means 31 are determined as described above. It is determined whether or not the refrigerant is leaking by comparing with the refrigerant, and when it is determined that the refrigerant is leaking, a notification signal Pc is output (step P). Then, a notification sound "beep, beep" is emitted from the speaker 13, so by confirming the notification sound, it is possible to recognize that there is a refrigerant leak and quickly take action.

Further, when determining in step O that the refrigerant is not leaking, the determining means 30 proceeds to step Q and outputs the notification signal Pd. Then, a notification sound "beep beep" is emitted from the speaker 13, so by confirming the sound, it is possible to recognize that the thermistor 23 has failed, and to deal with the problem. In short, since the determining means 30 has already determined that the cause of the compressor 8 being operated for a long time is not the locked state of the fan 6 or the leaked state of the refrigerant, it determines that the remaining cause is a failure of the thermistor 23. It is. The out-of-phase sound generation circuit 15 waits in step R until a reset button (not shown) is operated, and stops outputting the notification signal when it is determined that the reset button has been operated (step S).

Further, when the temperature of the freezer compartment 2 has sufficiently decreased and the output of the combination ON signal Sa from the comparator 24 has been stopped, the process moves from step E to step T, whereby the calculator 16 outputs the control signal Pa. Since the compressor 8 stops, even if the drive of the compressor 8 is intermittent based on the temperature of the freezing compartment 2,
Since no silencing control is performed when the drive is stopped, meaningless silencing control can be avoided.

In summary, the out-of-phase sound generation circuit 15 is configured to include a determining means 30 that determines which component has malfunctioned in the refrigeration system based on the noise received by the microphone 14 and notifies it from the speaker 13. Since there,
A new function of detecting abnormalities in the refrigeration system can be easily added using the microphone 14 and speaker 13 provided for adaptive control.

Furthermore, since there is no need to separately provide a circuit for detecting an abnormality in the refrigeration system, it is possible to prevent the overall configuration from becoming complicated while adding new functions.

Of course, in the above embodiment, 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 the inside of the machine room 7 to be 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 the above embodiment, the measured sound reception frequency characteristics and the reference sound reception frequency characteristics were compared by comparing frequency bands every 1/3 octave, but instead of this, frequency bands with large level differences were compared. It is also possible to compare only the 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 the above embodiment, the noise from the compressor 8 is detected by the vibration sensor serving as the detection means, but instead of this, the noise from the compressor 8 may be detected by, for example, a microphone.

Furthermore, instead of generating the notification sound from the speaker 13, a tape recorder or voice synthesis technology may be used to generate the sound from the speaker 13. In other words, when the locked state of fan 6 is detected, a voice saying "There is a fan not operating. Please contact service after checking that the door is ajar" is generated, and a refrigerant leak state is detected. If an abnormality is detected in one thermistor, a voice will be emitted saying, ``There is a risk of a gas leak. Please check if the door is ajar and contact service.'' There is a possibility that the door may be malfunctioning. Please check that the door is ajar and contact service." may be configured to generate a voice.

In the above embodiment, the deceptive sound from the compressor 8 is detected by the vibration sensor serving as the detection means, but instead of this, it may be configured to 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, in which 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 reception frequency characteristic diagram when the fan is not locked, Fig. 12 is a sound reception frequency characteristic diagram when the fan is locked, and Fig. 13 is a sound reception frequency characteristic diagram when the refrigerant is not leaking. , FIG. 14 is a diagram corresponding to FIG. 13 at the time of refrigerant leakage. In the figure, 1 is the refrigerator body, 6 is a fan, 7 is a machine room, 8 is a compressor, 10 is a defrosting water evaporator, 11 is a machine room cover, 11a is a heat radiation opening, 12 is a vibration sensor (detection means), 13 is a speaker (control sound generator), 14 is a microphone (auxiliary sound receiver), 15 is a reverse phase sound generation circuit, 1
6 is an arithmetic unit, 17 is an adaptive control circuit (control means), 23 is a thermistor, 30 is a judgment means, and 31 is a storage means.

Claims (1)

[Claims] 1. A refrigeration system comprising components such as a compressor housed in a machine room and driven intermittently, and a cooler 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 out of the permissible range, and for performing the changing operation until the monitored result falls within the permissible range; storage means for storing reference sound reception frequency characteristics by the auxiliary sound receiver when an abnormality occurs in one or more functions of the components; judgment means for comparing the sound reception frequency characteristic measured by the device with the reference sound reception frequency characteristic stored in the storage means and determining the component that has malfunctioned in the refrigeration system based on the comparison result. A silencer for a cooling device characterized by: