JPH02227573A - Silencer for cooling device - Google Patents

Abstract

PURPOSE:To enhance the additional value of a sound receiver by constructing an arrangement wherein the noise generated with drive of a compressor is canceled by interference with an artificial sound given by a sound emitter for controls, and providing possibility of judging the locked condition of the compressor from the sound receiving level at the sound receiver. CONSTITUTION:A machine room 7 is formed in the rear lower part of a refrigerator 1 so as to accommodate a rotary type compressor 8, condenser pipe, and water evaporator for defrosting. A microphone 12 as sound receiver in the machine room 7 converts the noise generated with drive of the compressor 8 into an electric signal, which is fed to a calculator 15 in an opposite phase sound generating circuit 14 so as to actuate a speaker 13 as a sound emitter for controls, and thereby the noise is canceled actively. If a certain specified level is not attained by the sound received level a certain period after starting of the compressor 8, it is judged that it is in locked condition, and a relay switch 23b is turned off to shut off the power supply 25.

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 silencing device for a cooling system 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 the noise from the machine room in which the compressor and the piping system connected thereto are housed. That is, in the machine room, the compressor itself generates relatively large noises (compressor motor traverse, 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 and structure of the compressor, and modifying the shape of the piping system. Attenuate vibrations in the vibration propagation path by doing things like Efforts are being made to increase losses.

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 B'9 control technology, active noise control has been developed that utilizes the interference of sound waves to reduce noise. Applications of the technology are noted. 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. By operating a control sound generator (for example, a speaker) based on U, 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.

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

The present invention has been made in view of the above-mentioned circumstances, and its object is to actively cancel the noise associated with driving a compressor based on the sound received by the sound receiver. It is an object of the present invention to provide a silencing device for a cooling device that can be used to protect a compressor from a locked state.

[Structure of the Invention] (Means for Solving Problem 37i) In order to achieve the above object, the present invention includes a sound receiver and a sound receiver that converts the noise generated by driving a compressor housed in a machine room into an electric signal. , a control sound generator that generates an artificial sound using a signal processed from the above-mentioned electric signal by a repeater, and the sound from the compressor is actively canceled by interference with the above-mentioned artificial sound. In the device,
Control means is provided for determining that the compressor is in a locked state and cutting off power to the compressor when the sound level received by the sound receiver does not reach a predetermined level after a predetermined time has elapsed from the drive start timing of the compressor. It is something.

(Function) The sound from the compressor is converted into an electric signal by the sound receiver, and the arithmetic unit operates the control sound generator based on a signal obtained by processing the electric 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.

On the other hand, when the compressor is in a locked state, the sound level from the compressor is low.

In this first case, the control means detects the pedestal level by the sound receiver after a predetermined time has elapsed from the timing when the compressor starts driving, and when the received sound level does not reach the predetermined level, the compressor is in the locked state. It determines that there is a problem and cuts off the power to the compressor. This prevents the compressor from remaining in a locked state for an unintentionally long time.

(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. 5 is a cooler disposed at the back of the freezer compartment 2; 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 pipe 9 and a defrosting water evaporation device 10 using so-called ceramic fins are housed.

Now, as shown in diagram T84 (here, the illustration of the condenser pipe 9 and the defrosting water evaporator 10 is omitted),
The machine room 7 has a rectangular opening only at its back, and this opening is opened and closed by a machine room cover 11. At this time, machine room cover 1
1, whose peripheral edge 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. There is.

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 bar 11 is made of a material (for example, metal such as iron) that has excellent thermal conductivity and high sound transmission loss.

Further, in the same figure ff14, 12 is a sound receiver such as a microphone placed in the machine room 7, which is sealed in the compressor 8 and is placed on the side opposite to the heat dissipation opening 11a (
They are arranged so as to face each other from the right side in the figure, and are provided so as to convert the sound from the compressor 8, which is a noise source, into an electrical signal. Reference numeral 13 denotes a speaker serving as a control sound device disposed in the machine room 7;
It is mounted and supported in a buried manner in a portion of the back wall portion (corresponding to the bottom wall portion of the refrigerator body 1) near the heat radiation opening 11a.

As shown in FIG. 1, the speaker 13 is operated by a control signal Pa obtained by processing an electric signal from the microphone 12 by a calculator 15 in the anti-phase sound generating circuit 14. , the processing of electrical signals as described above is
This is done based on the principle of silencing through active control as described below.

That is, to roughly explain the principle of silencing by active control with reference to FIG.
2. The sound received by the microphone 12 is R1, the sound at the heat dissipation opening 11a, which is the VNK quadrant, is R2, and the acoustic transfer functions between the sound output and human power points as described above are TIl, T2+ , TI2. When T22 is assumed, 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 calculated from the above equation as follows: S2 - (-712 R1 + Tl1 - R2)/(
Tll.T 22 - T 12.T 21), but in this case, since the goal is to make the sound level at the heat dissipation opening 11a zero, it can be set as R2-0. As a result, S27R1-T12/ (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 microphone 12 must be replaced by F-wheel T12/ (T12- T21-Tll・T22)
If the speaker 13 generates the sound S2 processed through a filter, the g-sound level at the heat dissipation opening 11a can theoretically be reduced to zero. The device is configured to provide a mill signal Pa to the speaker 13 while performing sound processing (calculation) at high speed.

On the other hand, in the first negative phase sound generation circuit 14, in addition to the arithmetic unit 15 that performs the above-mentioned active control, the compressor 8 is in the locked state B (a state in which it is not driven despite a'F11).
It has a control means 16 for determining whether or not it is, and receives a drive command (hereinafter referred to as a combination-on signal Sa) to the compressor 8 in order to realize the function.

Here, 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 in the band below 700 H2 degrees and in the range of 1.5 degrees, as shown in FIG. It becomes a state in which it has the property of becoming larger in the band of 5 to 5 KHz. 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 and the like, and an appropriate sound absorbing member is installed in the machine room 7. The microphone 12 as mentioned above can be easily muted by
Active control of noise by the speaker 13 and the computing unit 14 may be performed with a target frequency of 700 Hz or less.

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 larger than H (specifically, W=600mm, D=
H-200+-), 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-NXLX +Ny y +NzLz
/2 However, f is the resonance frequency (Hz), NX, N
y.

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

That is, as described above, when the depth dimension D-200--1 width-j method W-600ms and height dimension H-200ma+, the first constant tE in the X direction
The frequency fx of the wave is Ny -Nz-0, the speed of sound is C-340
, m/sec, fx -3401,2) /2 = 850Hz, and similarly, the frequencies ry and fz of the first standing wave in the Y and Z directions are fy -340 (110,6) 2 /2283H
z fz=340 ・ , /
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 by active control of noise using the speaker 13 or the like, the theoretical handling of the wavefront is fair, and the silencing control can be performed elegantly and with high precision.

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
The fan 6 and the fan 6 are configured to be electrically powered, and the circuits related to these will be briefly explained based on FIG. In other words, the thermistor 1 connected in series with the resistor 17
8 is provided to detect the temperature of the freezer compartment 2 (
(See FIG. 3), the thermistor 18 outputs a temperature signal sb indicating the temperature of the freezing compartment 2. Further, in the comparator 19, the temperature signal sb from the thermistor 18 and the reference voltage Vc output from the common connection point of the resistors 21 and 22 are compared, and the signal level of the temperature signal sb is compared.
When exceeds the reference voltage Vc, the comparison "J:A1.9
A high-level combination-on signal Sa is output from. With the above configuration, when the temperature of the freezer compartment 2 rises to a predetermined temperature, the signal level of the temperature signal sb from the thermistor 18 exceeds the reference voltage vc, and the comparator 19 outputs the combo-on signal Sa. The combination ON signal Sa from the comparator 19 is applied via an AND circuit 22 to the base of a transistor 24 (which drives a relay 23) tl. Here, the relay coil 23a of the relay 23 is connected so as to be excited when the transistor 24 is on, and when the relay switch 23b of the relay 23 is turned on in the excited state, the compressor 8 and the fan 6 are connected to the commercial AC power supply. 25 to drive these. Furthermore, when the relay switch 23b is turned on, various heaters 26 (for defrosting or preventing dew formation) provided in the refrigerator are connected to the AC power source 25, and these heaters generate heat.

Then, the control means 16 determines whether or not the compressor is in the locked state based on the human power status of the combination on signal Sa and the timing operation of the built-in timer 16g, and based on this, the control means 16 outputs the notification signal Pb from the calculator 15. At the same time, a low-level regulation signal Sc is outputted to the AND circuit 22 as appropriate. Here, when the arithmetic unit 15 outputs the notification signal, the speaker 13 emits a notification sound such as "bee", and when the control means 16 outputs the low level regulation signal Se, the combination on signal Sa is emitted. Passage through the AND circuit 22 is restricted.

Therefore, in the following, the functions of the negative phase sound generation circuit 14, that is, the functions of the arithmetic unit 15 and the control means 16 will be explained with reference to the flowchart shown in FIG.

That is, when the temperature of the freezer compartment 2 rises and the signal level of the temperature signal sb from the thermistor 18 exceeds the reference voltage VC,
A combination ON signal Sa is outputted from the comparator 19, and in response to this, the relay switch 23b of the relay 23 is turned on, thereby connecting the AC power supply 25 to the combination brake sensor 8 and starting its driving. At this time, the anti-phase sound generation circuit 14 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 resets the timer 16a (step B) and also resets the timer 16a (step B). 16a (step C). Then, the timer 16a waits until the time measured by the timer 16a reaches, for example, 6 seconds (step D), and when the time reaches 6 seconds, it is determined whether or not the combination on signal Sa is input (step E). And Combon signal S
When a is given (during a drive command to the compressor 8), it is determined whether the sound level received by the microphone 12 is, for example, 60 dB (Lln) or less (
Step F). At this time, if the starting ability of the compressor 8 is sufficient, the starting is normally completed 2 to 4 seconds after it is started, so after 6 seconds, the driving of the compressor 8 is stopped. The accompanying noise is 60
dB (Lln) or more. Therefore, when the compressor 8 is started normally, in step F, "
In this case, the audio signal from the microphone 12 is sampled (step G), and
After processing the sampled acoustic signal based on the above-described acoustic transfer function (step H), a control signal Pa based on the processing is output (step I), and then the process returns to step E. As a result, the control signal Pa is given to the speaker 13 from the out-of-phase sound generation circuit 14, and the control sound is emitted from the speaker 13 in response to this, so that the noise caused by driving the compressor 8 and the control from the speaker 13 are reduced. Active control is performed in which the sounds interfere with each other in the heat dissipation opening 11a, and the sound level is reduced. Then, the reverse phase sound generation circuit 14 operates from step E to step I while the combination ON signal Sa is being manually inputted.
Forms a loop that repeatedly executes the routine up to. As a result, when the compressor 8 is started normally, a control signal P corresponding to the noise accompanying the drive of the compressor 8 is generated.
a is output to the speaker 13 and active control is performed in real time, so the 78'll from the compressor 8
Even if the components fluctuate, the noise can be attenuated by following the fluctuations.

Now, when the load on the compressor 8 becomes greater than the limit due to insufficient lubrication of the compressor 8 and the driving friction force of the movable mechanical elements increases, or the pressure of the compressed gas becomes abnormally high, etc. The compressor 8 may be in a locked state in which it does not operate even though it is energized. In such a case, since the compressor 8 is not driven, it is not only meaningless to perform the above-mentioned silencing control, but also if the microphone 12 receives ambient noise, the control based on that noise may be There is a possibility that 1lTI will be emitted from the light force 13 and become a noise source. Therefore, the locked state of the compressor 8 is detected and dealt with as follows. In other words, as mentioned above, if the starting ability of the compressor 8 is sufficiently high, the starting of the compressor 8 will be completed when, for example, 6 seconds have passed since the starting of the compressor 8.
is in the locked state, it will not be activated even after 6 seconds have elapsed, and at that point the microphone 12
The sound level received by the device is lower than 60 dB (Lln). Therefore, when the compressor 8 is in the locked state, the negative phase sound generation circuit 14 determines rYEsJ in step F, which is the noise level determination step, moves to step J, and stops outputting the control signal Pa. As a result, since no control sound is emitted from the speaker 13, meaningless muffling control can be avoided.

Subsequently, the out-of-phase sound generation circuit 14 outputs a notification signal pb in step K, and in response to this, the speaker 13 emits a notification sound such as "beep". Next, the anti-phase sound generation circuit 14 resets the timer 16a (step L), starts the timer 16a (step M), and waits until the timer time elapses, for example, 30 minutes (step N). ), and stops outputting the notification signal pb (step O). As a result, a 30-minute alarm will be emitted from the speaker 13, so people around the refrigerator will recognize that the compressor 8 is locked and take out the food stored in the refrigerator. The abnormal situation can be quickly dealt with.

Next, the anti-phase sound generation circuit 14 outputs the regulation signal Sc at a low level in step O. As a result, the combination ON signal Sa from the comparator 19 can no longer pass through the AND circuit 22, so the transistor 24, which had been on until then, turns off, and in response, the relay switch 23
b turns off.

Then, the compressor 8 is disconnected from the AC i'i source 25, so that the compressor 8 is not kept locked for a long time, thereby making it possible to prevent the compressor 8 from burning out. Furthermore, at the same time as the compressor 8 is disconnected from the AC power source 25, various heaters 26 provided in the refrigerator are disconnected from the AC power source 25. Since it is separated from the 8iIl:-ta 26, the safety fuse attached to each 8iIl:-ta 26 can be made unnecessary. It is desirable that the alarm be emitted from the speaker 16 for at least 30 minutes to ensure the attention of the surrounding people, but if the time is set too long, the compressor 8 Since the time it takes for the power supply to be cut off becomes longer and the risk of the above-mentioned problems increases, it is desirable that the time be about 30 minutes to 1 hour.

In addition, in the case of the above embodiment, when the temperature of the freezer compartment 2 has sufficiently decreased and the combination ON signal Sa is not output from the comparator 19, the negative phase sound generation circuit 14 shifts from step E to step Q. and stops outputting the control signal PR.

As a result, even if the compressor 8 is driven intermittently based on the temperature of the freezer compartment 2 after the compressor 8 has started normally, the silencing control will not be performed when the drive is stopped. Meaningful silencing control can be prevented.

Incidentally, in the case of the above embodiment, steps A, B, and C.

The control means 16° takes charge of steps D, F, J, L, M, O, and P, and the arithmetic unit 15 takes care of steps E, G, H, and I.

In summary, the out-of-phase sound generation circuit 14 includes a computing unit 15 that performs active control of noise based on the sound signal received by the microphone 12, and also includes a calculator 15 that performs active control of noise based on the sound signal received by the microphone 12. Compressor 8
Since the compressor 8 is configured to include a control means 16 for detecting whether or not the compressor 8 is in the locked state, a new function is provided in which the locked state of the compressor 8 can be detected while using the microphone 12 provided for active control. can be added. Therefore, since there is no need to separately provide a circuit for detecting the locked state of the compressor 8, it is possible to prevent the overall configuration from becoming complicated while adding new functions.

Furthermore, since the negative phase sound generation circuit 14 is configured to cut off the power to the compressor 8 when it is determined that the compressor 8 is in the locked state, it is possible to prevent problems caused by energizing the compressor 8 in the locked state. This can be reliably prevented.

Of course, in the above embodiment, the machine room 7 has the heat radiation opening 1
Since it is communicated with the outside through 1a, the temperature in the machine room 7 will not rise abnormally due to heat generated when the compressor 8 is driven. 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 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 sound generated by the drive of the compressor housed in the machine room is transmitted from the control sound generator operated by the signal processed by the arithmetic unit. In a silencer for a cooling device, which actively cancels noise due to interference with artificial noise, when the sound level received by the sound receiver does not reach a predetermined level after a predetermined time has elapsed from the timing when the compressor starts driving, il that determines that the above compressor is in a locked state
- Since the control means is provided, the sound receiver can be used not only for active control but also for protecting the compressor from a locked state, thereby increasing the added value of the sound receiver. You can expect.

[Brief explanation of the drawing]

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. 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 cover, 11a is an opening for heat radiation, 12 is a microphone (sound receiver), 13 is a speaker (sound generator for control), 14 is a reverse phase sound generation circuit, 1
5 is a computing unit, and 16 is a control means.

Claims (1)

[Claims] 1. Converting the sound generated by the drive of the compressor housed in the machine room into an electrical signal using a sound receiver, and operating the control sound generator based on the signal processed by this electrical signal using an arithmetic unit. A silencing device for a cooling device that actively cancels out sound radiated from the machine room to the outside, wherein the level of sound received by the sound receiver after a predetermined period of time has elapsed from the drive start timing of the compressor. 1. A silencer for a cooling device, comprising control means for determining that the compressor is in a locked state and cutting off power to the compressor when the compressor does not reach a predetermined level.