JPH02225965A - Noise suppressor for cooling device - Google Patents

Abstract

PURPOSE:To improve an additional value of a sound receiver by installing a control means which judges that a compressor is in a locked state when a sound receiving level by the receiver has failed to reach a specified level. CONSTITUTION:A noise suppressor for a cooling device which is designed to actively cancel sound produced from a compressor by the interruption of an artificial sound, comprises a sound receiver 12 which converts sound generated resultant from the drive of a compressor 8 housed in a machine room 7 into an electric signal, a control sound generator 13 which generates artificial sound based on the electric sign processed by a computing element 15, a control means 16 which judges that the compressor is in a locked state when a sound receiving level by the sound receiver 12 has failed to reach a specified level. Therefore, the sound receiver can be used to detect the locked state of the compressor and enhance an additional value of the sound receiver as well.

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 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 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 vibrations, and such machine room noise accounts for most of the refrigerator noise. Therefore, suppressing the noise from the machine room will greatly contribute to the overall noise reduction of the refrigeration system (1+1).

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 the machine room of a refrigerator inside the shell, there are multiple openings for heat dissipation due to the need to release heat generated by the compressor to the outside, and noise is emitted from these openings to the outside. will leak 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 sound 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 vi (sound from the noise source) at the target point, and the person can hear the sound and the original sound. The idea is to attenuate the original sound by interfering with the

(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 improvement in this point is desired.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to actively cancel out noise caused by driving a compressor based on the sound received by a sound receiver.
It is an object of the present invention to provide a silencer for a cooling device in which the above sound receiver can also be used to detect the locked state of a compressor, thereby improving the added value of the receiver F5W.

[Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, the present invention provides a sound receiver that converts the sound generated by driving a compressor housed in a machine room into an electrical signal. , a sound muffling device for a cooling device, which is equipped with a control sound generator that generates an artificial sound using a signal obtained by processing the electric signal by a computing device, and actively cancels the sound from the compressor by interfering with the artificial sound. In,
The control means is provided for determining that the compressor is in a locked state 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.

(Work) tl) The sound from the compressor is converted into an electrical signal by a sound receiver, and the arithmetic unit operates a 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.

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

In this case, the control means detects the sound level received by the sound receiver after a predetermined time has elapsed from the start of driving the compressor, and determines that the compressor is in a locked state when the sound reception level does not reach the predetermined level. do.

(Example) An example in which the present invention is applied to a refrigerator will be described above.

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 main 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.

Now, as shown in FIG. 4 (here, the illustration of the condenser vibrator 9 and the defrosting water evaporator 10 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 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 dissipation opening 1ta. The machine room cover 11 is made of a material (for example, gold such as iron!j4) that has excellent thermal conductivity and high sound transmission loss.

Further, in FIG. 4, reference numeral 12 denotes a pedestal, such as a microphone, placed in the machine room 7, which is located on the opposite side of the compressor 8 from the heat dissipation opening 11a (on the right side in the figure). The compressor 8 is arranged so as to face the compressor 8, and is arranged so as to convert the sound from the compressor 8, which is the source of the noise, into an electrical 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.

As shown in FIG. 1, the speaker 13 is operated by a control signal Pa obtained by processing the electric signal from the microphone 12 in the out-of-phase sound generation 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 radiation opening 11a which is the control target point is R2, and the acoustic transfer function between the sound output and human power points as described above is T.
l, T21, Tl2. 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- (-Tl2・R1+Tl1- R2)/cT
ttφT 22-712·T 21), but 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, S2-R1-712/ (Tl2・T21-Tit-T
22). As can be understood from this equation, in order to eliminate the sound R2 at the heat dissipation opening 11a, a filter of F-T12/(T12・T21-Tll conflict T22) is applied to the sound R1 received by the microphone 12. If the processed sound S2 is generated from the speaker 13, the sound level at the heat dissipation opening 1.1a can theoretically be reduced to zero. It is configured to apply a control signal Pa to the speaker 13 while processing (calculating) sound at a high speed.

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 of about 700H2 or less and 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,
Noise on the high frequency side can be attenuated by transmission loss in the machine room cover 11, etc., and can be easily muffled by installing an appropriate sound absorbing member in the machine room 7, so as mentioned above. The active control of noise by the microphone 12, speaker 13 and computing unit 14 is 700
The target frequency may be set to 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. 1f1 is required to perform it easily and accurately. Therefore, in this embodiment, among the three-dimensional depth, width, and height dimensions W and H in the machine room 7 shown in FIG.・
J-hori.

Set higher than H (specifically, W-600ss, D-
H-200sml setting), the machine room 7
The structure is such that the standing wave of sound within is established only in the layer 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)' +(N
Z/LZ)2/2 However, [is the resonance frequency (Hz),
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,
Frequency fX, r of the first standing wave in each direction of y and z
y and fz can be found.

That is, as mentioned above, when the depth dimension D-200-1, the width dimension W-600+s, and the height dimension H-200sn, the frequency fX of the first standing wave in the X direction is , Ny wmNz −Os, g speed C= 3
40 m/sec, fx -340, /2 850Hz, and similarly, the frequencies fy, fz of the first standing wave in the Y and X directions are fy-340J 1, /2283H
z fz =340 (10,2) /2850H2. As a result, the target frequency (-700H
2) In the following, the standing wave of noise in the machine room 7 is expressed 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 noise control using the speaker 13 or the like, the wavefront can be theoretically handled easily, and the silencing control can be performed easily and accurately.

On the other hand, in addition to the arithmetic unit 15, the reverse sound generation circuit 14 has a control means 16 for determining whether or not the compressor 8 has been started normally.

Then, in order to realize the above function, the control means 16 sends a drive command (hereinafter referred to as a compressor-on signal Sa) to the compressor 8.
), and controls the functions of the arithmetic unit 15 based on the input status of the combination-on signal Sa and the operation of the built-in timer 16a at =1. Therefore, the electric circuit for outputting the comb-on signal Sa is a circuit that is originally provided in the refrigerator, and is configured so that the compressor 8 and the fan 6 are driven during the output period of the comb-on signal Sa. , and related circuits will be briefly explained based on FIG.

In other words, the thermistor 18 connected in series with the resistor 17 is provided to detect the temperature of the freezing compartment 2 (see Figure 3), and the thermistor 18 outputs a temperature signal sb indicating the temperature of the freezing compartment 2. It has become so. and,
In the comparator 19, the temperature signal s from the thermistor 18
When the signal level of the temperature signal sb exceeds the reference voltage VC, the comparator 19 outputs a high-level combination signal Sa. be done. With the above configuration, when the temperature of the freezer compartment 2 rises to a predetermined temperature, the signal level of the temperature signal slJ from the thermistor 18 changes to the reference voltage V.
By exceeding e, the comparator 19 outputs a combination-on signal S.
a is output. The combination ON signal Sa from one comparator is applied to the base of a transistor 23 for driving the relay 22. Here, relay 22
The relay coil 22a is connected to be excited when the transistor 23 is on, and when the normally open contact 22b of the relay 22 is closed in the excited state, the commercial AC power supply 24 is connected to the compressor 8 and fan 6. These are now being driven.

Therefore, in the above, the functions of the inverse chord 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 SL+ from the thermistor 18 exceeds the reference voltage VC, the comparator 19 outputs the combo-on signal Sa, and in response, the relay switch 22b of the relay 22 is activated. When the AC power supply 24 is closed, the AC power supply 24 is connected to the compressor 8, and the drive of the compressor 8 is started. At this time, the anti-phase sound generation circuit 1
4 waits until the input 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 starts the timer 16a (step C). ). Then, the process 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 manually activated (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 (+, 10) or less (step F). At this time, if the starting ability of the compressor 8 is sufficient, the
Normally, the startup is terminated after 4 seconds, so
After 6 seconds have elapsed, the noise generated by driving the compressor 8 is 60 dB (1, In) or more. Therefore,
If compressor 8 is started normally, step F
In this case, the acoustic signal from the microphone 12 is sampled (step G), and the sampled acoustic signal is processed based on the acoustic transfer function described above (step H). Step I) to output a control signal Pa based on the processing;
After this, return 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 speaker 13 are
Active control is performed in which the control sounds from the heat dissipation opening tla interfere with each other and the sound level is lowered. The anti-phase sound generation circuit 14 forms a loop that repeatedly executes the routine from step E to step I while the combination-on signal Sa is input. As a result, when the compressor 8 is started normally, 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. Even if the acoustic components of the system fluctuate, the noise can be attenuated by following the fluctuations.

Now, the load on the compressor/socket 8 becomes greater than its limit due to insufficient lubrication of the compressor 8, resulting in an increase in the driving friction force of the movable mechanical elements, or due to an abnormally high pressure of the compressed gas. Sometimes, the compressor 8 may be in a locked state in which it does not start even if the AC power source 24 is connected to it. In such a case, since the compressor 8 is not operating, it is not only meaningless to perform the above-mentioned silencing control, but also the microphone 1
If ambient noise is received, there is a risk that control sounds based on the noise will be emitted from the speaker 13 and become a noise source. Therefore, the locked state of the compressor bolt 8 is detected and dealt with as follows. In other words, as mentioned above, if the startup ability of the compressor 8 is sufficiently high, the startup will be completed when, for example, 6 seconds have passed since the start of startup, whereas if the compressor 8 is in a locked state is not activated even after 6 seconds have elapsed, and at that point the sound level received by microphone 12 is 60 dt.
3 (LIr+). Therefore, when the compressor 8 is in the locked state, the out-of-phase sound generation circuit 14
In step F, which is a noise level determination step, it is determined that rYESJ is reached, and the process proceeds to step J, where the control signal P is
Stop the output of a. As a result, the control r from the speaker 13
Since the eight sounds are no longer emitted, meaningless muting control can be avoided.

In this case, when the temperature of the freezer compartment 2 has dropped sufficiently by T and the combination ON signal Sa has not been output from the comparator 19, the reverse phase sound generation circuit 14 shifts from step E to step K. and stops outputting the control signal Pa. 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,
When the drive is stopped 1, the silencing control is not carried out, so that meaningless silencing control can be prevented in this case as well.

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

D, F, and J are shared by the control means 16, and step E is performed.

G, H, and I are shared by the 'et calculator 15.

In summary, the out-of-phase sound generation circuit 14 includes an arithmetic 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 noise control based on the sound signal received by the microphone 12, and also based on the noise received 6 seconds after the start of the compressor 8. Compressor 8
Since the control means 16 is configured to detect whether or not the compressor 8 is in the locked state, it is possible to detect the locked state of the compressor 8 while using the microphone 12 provided for the active Lit III. Therefore, there is no need to separately provide a circuit for detecting the locked state of the compressor 8, which prevents the overall configuration from becoming complicated while adding new functions. Can be done.

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,
Also from this point of view, the rise of 7a inside the machine room 7 can be suppressed to a low level.

It should be noted that the present invention is not limited to the above-mentioned 11 embodiments shown in the drawings, and for example, an outdoor unit of an air conditioner or a refrigerated sissy case may be applied as a cooling device to be silenced. Various modifications can be made without departing from the above.

[Effect of the Invention J 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 computing 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, Since one stage of control is provided to determine whether the compressor is in the locked state, the sound receiver can be used not only for active control but also to detect the locked state of the compressor, thereby increasing the added value of the sound receiver. It has an excellent effect of being able to achieve the desired results.

[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, 118 is a heat radiation opening, 12 is a microphone (receiver), 13 is a speaker (control sound generator), 14 is a reverse phase sound generation circuit,
15 is a computing unit, and 16 is a control means. Applicant: Toshiba Corporation

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 when the compressor does not reach a predetermined level.