JP3275486B2 - Soundproofing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproofing device for preventing noise from the outside of a room from entering the room through an opening of the room.

[0002]

2. Description of the Related Art A conventional soundproof device will be described with reference to a soundproof room shown in FIG.

[0003] In a production process of a factory, a process for inspecting abnormal operation noise of a product is performed in a soundproof room 1 as shown in FIG. The soundproof room 1 is composed of a room 3 surrounded by a soundproof wall 2, and the inside of the room 3 is subjected to a sound absorbing process by a sound absorbing material 4. It has two openings 6 through which the belt conveyer 5 flowing through the production line passes, and this opening 6 is configured to be opened and closed by a door 8 that slides up and down every time a product 7 that is a product flows. . Here, 9 is an operator.

[0004] In the above configuration, the noise of a press machine or an air conditioning machine installed in the factory is sound-absorbed and absorbed by a soundproof device.
The inspection work for abnormal noise is performed in a quiet environment.

[0005]

However, in the above-described conventional configuration, the above-mentioned mechanical noise containing a large amount of low frequency components cannot be sufficiently prevented from sound only by the sound insulation or sound absorbing effect of the soundproof room 1, resulting in abnormal sound of the product. Inspection cannot be performed sufficiently, and the high frequency of the cylinder driving device 10 that opens and closes the door 8
There is a problem that an impact sound containing a large amount of sound gives the worker 9 an auditory and mental pain.

The present invention solves the above-mentioned problems, and reduces noise near the worker's head in the soundproof room 1 by the phase interference of sound waves, eliminates the door 8, and manufactures the product on a belt conveyor. By changing the area of the opening according to the size of the object, the cylinder drive device when opening and closing the door
By reducing the impact sound containing many high frequencies,
Noise can be reduced widely from frequency to high frequency.
To remove the pain of the worker
Are the first objects. And a second pressure detector
Place the sound wave generator at the position where the signal of
Moving, the noise reduction effect due to phase interference is widened.
It is a second object to realize a high frequency range .

[0007]

In order to achieve the first object, the present invention provides a soundproof room having an opening, a first pressure detector for detecting sound outside the opening, and a soundproofing device. A second pressure detector for detecting a sound inside the chamber, and a signal from the first pressure detector and a signal from the second pressure detector,
An arithmetic unit for calculating, by adaptive control, a sound wave signal in which noise near the second pressure detector is suppressed by phase interference caused by sound waves; and a sound wave generation unit for generating the sound waves inside the room, inside the soundproof room. And the opening of the opening
An opening area variable device for changing an opening area is provided .

[0008] Then, in order to achieve the second object, proof
Sound wave generating means on the sliding part of the sliding device installed inside the sound chamber
It is provided with .

[0009]

According to the present invention, with the above-described structure, a sound wave having a phase opposite to that of the noise inside the soundproof room is output to the vicinity of the worker's head to generate phase interference of the sound wave, so that the noise can be greatly reduced. By changing the area of the opening in accordance with the size of the product flowing on the belt conveyor, the substantial sound passage area can be reduced, and the total noise passing amount can be greatly reduced. . Then, by moving the sliding device a sound wave generating means a position signal of the second pressure detector is reduced, a wide range of the silencing effect by the phase interference
It can be realized in the frequency range .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the first invention will be described below with reference to FIGS. 1 to 6 using a soundproof room for abnormal sound inspection used in a production factory.

As shown in FIG. 1, the soundproof room 11 has an inlet 12 and an outlet 13, and the belt conveyor 5 passes from the inlet 12 to the outlet 13, and the product 7 is placed on the belt conveyor 5. Is flowing. And, a first microphone 14 as a first pressure detector provided one each on the outside of the inlet 12 and the outlet 13,
15, near the head 16 of the worker 9 inside the soundproof room 11,
Second microphones 17 and 18 which are second pressure detectors arranged so as to sandwich the head 16 are provided. Also, based on the signals of the first microphones 14 and 15 and the signals of the second microphones 17 and 18, the second microphones 17 and
An arithmetic unit 19 for calculating, by adaptive control, a signal in which sound waves in the vicinity of 18 are suppressed by phase interference due to sound waves, and muffler speakers 20 and 21 as sound wave generating means for generating the sound waves are connected to the head of the worker 9. 2 at the position sandwiching the part 16
It was set as the composition provided.

Here, the arithmetic unit 19 is configured as shown in FIG. The first arithmetic unit 19-A includes first and second adaptive digital filters 22 and 23 for filtering the signal of the first microphone 14.

The filter coefficient of the first adaptive digital filter 22 is determined by the signal of the first microphone 14 and the second
An arithmetic unit (LMS) 24 for calculating a first filter coefficient for realizing a first adaptive digital filter 22 that reduces the signal of the second microphone 17 based on the signal of the microphone 17; Microphone 14
(LMS) 25 for calculating a second filter coefficient for realizing a first adaptive digital filter that reduces the signal of the second microphone 18 based on the signal of the second microphone 18 and the signal of the second microphone 18 Are synthesized by the two coefficients calculated by

The second adaptive digital filter 2
The filter coefficient of 3 is based on the signal of the first microphone 14 and the signal of the second microphone 17, and the first adaptive digital filter 23 for realizing the second adaptive digital filter 23 in which the signal of the second microphone 17 is reduced. (LMS) 26 for calculating the filter coefficient of the first and second microphones 18 and 18 based on the signal of the first microphone 14 and the signal of the second microphone 18
A second signal such that the signal of the second microphone 18 becomes small
Is configured by two coefficients calculated by a calculation device (LMS) 27 for calculating a second filter coefficient for realizing the adaptive digital filter 23 of FIG.
Here, 28, 29, 30, and 31 are the speakers 2 respectively.
Correction filters C11, C12, C2 for correcting the frequency characteristics of transmission of sound from 0 to the second microphones 17, 18 and from the speaker 21 to the second microphones 17, 18.
1, C22.

Further, the second arithmetic unit 19-B includes a first arithmetic unit 19-B.
And third and fourth adaptive digital filters 32 and 33 for filtering the signal of the microphone 15. The filter coefficient of the third adaptive digital filter 32 is determined by the signal of the first microphone 15 and the signal of the second microphone 17.
An arithmetic unit (LMS) 34 for calculating a first filter coefficient for realizing an adaptive digital filter that reduces the signal of the second microphone 17 based on the signal of
The signal of the first microphone 15 and the second microphone 1
(LMS) 3 for calculating a second filter coefficient for realizing an adaptive digital filter 32 such that the signal of the second microphone 18 is reduced based on the signal of No. 8
5 are combined by the two coefficients calculated.

A fourth adaptive digital filter 3
The third filter coefficient is a first filter coefficient for realizing an adaptive digital filter 33 in which the signal of the third microphone 17 is reduced based on the signal of the first microphone 15 and the signal of the second microphone 17. (LMS) 36 for calculating the following formula, and the first microphone 15
Is calculated by a calculation device (LMS) 37 that calculates a second filter coefficient for realizing the adaptive digital filter 33 that reduces the signal of the second microphone 18 based on the signal of the second microphone 18 and the signal of the second microphone 18. Done 2
It is configured to be composed by two coefficients. Where 3
8, 39, 40 and 41 are the second from the speaker 20 respectively.
, And correction filters C11, C12, C21, C22 for correcting the frequency characteristics of sound transmitted from the speaker 21 to the second microphones 17, 18.

The signals output from the arithmetic units 19-A and 19-B are mixed by synthesizers 42 and 43 to reproduce the speakers 20 and 21, respectively.
Here, the signal of each microphone is converted into a digital signal by an A / D converter and processed by an arithmetic unit, and the signal after the signal processing is converted into an analog signal by a D / A converter. , Are input to drive amplifiers 44 and 45 for driving the muffling speakers 20 and 21. Note that the A / D converter and the D / A converter are omitted in the figure.

According to the above configuration, noise outside the soundproof room 11 is generated by the signals of the first microphones 14 and 15 provided outside the entrance 12 and the exit 13 and the second microphone 17.
The antiphase sound calculated by the first and second arithmetic units 19-A and 19-B based on the noise signal detected by the signal 18 is
The sound is generated by the individual sound loudspeakers 20 and 21 and causes phase interference to mute the sound. And adaptive digital filters 22, 23, adapting to the ever-changing noise
The sound can be silenced by changing the characteristics of 32 and 33 to maintain the silencing effect. In addition, since two second microphones 17 and 18 and two muffling speakers 20 and 21 are arranged in the vicinity of the head 16 of the worker 9, silencing can be performed at multiple points as shown in FIG. As a result, a large sound deadening space can be obtained. Where 4
Reference numerals 2 and 43 denote individual silencing spaces, and reference numeral 44 denotes an image of a synthetic silencing space. In particular, in a low-frequency band, the wavelength is longer than the interval between the second microphones, and the silencing space after synthesis is not generated locally but can be obtained almost uniformly as shown in FIG. In the soundproof room in the factory, a great noise reduction effect can be obtained. The high frequency band is absorbed by the sound absorbing material used for the wall in the soundproof room, and has a low sound pressure level in the soundproof room. Therefore, noise reduction can be realized in a wide frequency range from a low frequency to a high frequency.

Further, as a result, the door that shuts off the soundproof room 11 can be eliminated, so that the impact sound of closing the door does not occur, and the worker 9 inside suffers both auditory and mental discomfort. Can not give. In addition, a power source such as a cylinder driving device for opening and closing the door is not required, so that the construction work of the soundproof room can be simplified, equipment such as a compressor is not required, and the soundproof room can be easily installed in the factory. The elimination of the driving device prevents noise from being generated outside the soundproof room, and has the effect of reducing noise in the entire factory.

[0020] Then, as shown in FIG. 4, just before the entrance portion 12 of the belt conveyor 5, the product size detector 45
And the opening of the inlet 12 and the outlet 13 is provided with an opening area variable device 46 for changing the opening area. Here, 47 is a drive device of the opening area variable device, and 48 is an opening / closing control device that controls the opening area variable device based on a signal of the size detecting device.

With such a configuration, the area of the opening is an optimum height slightly higher than the product according to the height of the product, and the opening area can be minimized. Therefore, the noise that enters the soundproof room from the opening is reduced as the opening area is smaller, so that the noise inside the soundproof room can also be reduced. In particular, low-frequency noise can easily enter due to the sound diffraction phenomenon, but high-frequency noise has a high level of straightness, is cut off by the opening area variable device 46, makes it difficult to enter, and greatly attenuates high-frequency noise. Can be. Then, as described in the first invention, noise that enters through the minimally remaining opening, particularly low-frequency noise, is reduced by the phase interference of the opposite-phase sounds generated from the speakers 20 and 21. By these combinations, the noise in the soundproof room can be significantly reduced.

A plurality of products having different shapes may flow on one belt conveyor 5 due to production adjustment. Is detected and the opening area of the soundproof room is automatically minimized at all times, so that noise entering through the opening can always be minimized, and there is an effect that production of products having different shapes can be supported.

As shown in FIGS. 5 and 6, if the second microphones 49 and 50 are installed near the left and right ears 52 and 53 of the operator , noise near the ears can be eliminated.
Obviously, a great silencing effect can be obtained. Where 5
1 is a work cap on which the second microphones 49 and 50 are installed.
is there.

Next, the second invention will be described with reference to FIG. Portions having the same structure and the same function as those of the first embodiment are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described.

As shown in FIG. 7, the speakers 20 and 21 as sound wave generating means were installed inside the soundproof room by a sliding device 55. The control device 56 of the sliding device 55
Receives the signal from the arithmetic unit 19 and slides the speakers 20 and 21 to positions where the signals of the second microphones 17 and 18 become small. Here, reference numeral 57 denotes a sliding portion.

With such a configuration, the speaker 2 is located at a position where the signals of the second microphones 17 and 18 become small.
By moving 0 and 21 by the sliding device 55, the noise reduction effect by the phase interference can be improved. That is, a sound pressure distribution may be defined as a sound mode in a partitioned space such as a soundproof room. There are a portion that hits the antinode of high sound pressure, such as a standing wave, and a portion that hits a node with low sound pressure, and the generation position is determined by the frequency. When the frequency of the noise cannot be specified or when the frequency of the noise fluctuates, the position of the speaker determined at the beginning may correspond to the position of the antinode of the acoustic mode. In this case, even if the frequency is generated at the position of the antinode, the vicinity of the node is not affected. Therefore, the speaker must be moved from this position to control the sound pressure near the node. If the signal from the second microphones 17 and 18 does not fall below a specific level by the arithmetic unit 19, the influence of the acoustic mode is considered, and therefore, a command is issued to the control unit 56 to change the position of the speaker. In accordance with this command, the control device changes the mounting position of the speaker. As a result, it is possible to deviate from the position of the antinode of the acoustic mode and increase the sound deadening effect.

[0027]

As described above, the soundproofing device according to the present invention has the first pressure detection for detecting the sound outside the opening of the soundproofing room.
And sound near the head of the worker in the soundproof room
A second pressure detector and a signal from the first pressure detector
The second pressure detection is performed based on a signal of the second pressure detector.
Noise near the vessel is suppressed by phase interference caused by sound waves
An arithmetic unit for calculating the sound wave signal by adaptive control;
A sound wave generator for generating the sound wave in a sound chamber;
Provide a variable opening area device to change the opening area of the mouth.
And the sound signal of the noise signal outside the soundproof room and the antiphase signal
Is output near the worker 's head inside the soundproof room,
Interference can be generated, so there is no door
Also significantly reduces low-frequency noise around the worker's head
Opening that can be used as a noise entrance
In order to make the optimal opening height according to the size of the product,
The effect of minimizing the ingress of high-frequency noise through openings
There is a wide range of frequencies by combining the two effects.
Noise in several ranges can be reduced, and abnormal noise in the factory
Inspections can be performed with high precision without mental pain
Wear. And the sliding device installed in the soundproof room
By providing sound wave generating means in the section, the sound wave generating means
It can be moved to the optimal position and various sound modes
A wide range of frequencies that can correspond to the frequency to be generated
Even if the frequency changes in the range, the noise reduction effect can always be obtained to the maximum.

Further, since the opening height is set to an optimum value according to the size of the manufacturing section, there is an effect that the entrance of noise from the opening can be minimized.

Further, by providing two second microphones near the worker's head, the noise near the worker's head can always be suppressed even when the worker moves.

Further, by moving the loudspeaker to an optimum position by the sliding device, a maximum silencing effect can be obtained regardless of the acoustic mode.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a soundproofing device showing one embodiment of the present invention.

FIG. 2 is a system diagram of an arithmetic unit of the apparatus.

FIG. 3 is a diagram illustrating an effect of the present invention.

FIG. 4 is a side sectional view of a soundproofing device showing another embodiment of the present invention.

FIG. 5 is a side cross-sectional view of a soundproofing device showing still another embodiment of the present invention.

FIG. 6 is an explanatory view showing an example of use of the device.

FIG. 7 is a side sectional view of a soundproofing device showing another embodiment of the present invention.

FIG. 8 is a side sectional view of a conventional soundproofing device.

[Explanation of symbols]

Reference Signs List 5 Belt conveyor 7 Product 9 Worker 11 Soundproof room 12 Inlet opening 13 Outlet opening 14, 15 First microphone as first pressure detector 16 Head of worker 17, 18 Second pressure Second microphone 19 as a detector 19 Arithmetic unit 20, 21 Silencing speaker 46 Opening area variable device 51 Work cap 55 Sliding device 57 Sliding part

Continuation of front page (56) References JP-A-3-42999 (JP, A) JP-A-5-279903 (JP, A) JP-A-5-61489 (JP, A) JP-A-6-240776 (JP) JP-A-7-64571 (JP, A) JP-A-7-5199 (JP, U) JP-A-3-34261 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB G10K 11/178 E04H 1/12 302 E04H 5/02

Claims (2)

(57) [Claims] 1. A soundproof room having an opening, and an outside of the opening.
A first pressure detector for detecting the sound of the soundproof room;
A second pressure detector for detecting sound near the trader's head;
The signal of the first pressure detector and the signal of the second pressure detector
The noise near the second pressure detector is converted into a sound wave based on the
The acoustic signal suppressed by the phase interference
An arithmetic unit for calculating the sound wave and emitting the sound wave inside the soundproof room.
A soundproofing device comprising: a generated sound wave generator; and an opening area variable device for changing an opening area of the opening. 2. A soundproof room having an opening, and an outside of the opening.
A first pressure detector for detecting the sound of the soundproof room;
A second pressure detector for detecting sound near the trader's head;
The signal of the first pressure detector and the signal of the second pressure detector
The noise near the second pressure detector is converted into a sound wave based on the
The acoustic signal suppressed by the phase interference
An arithmetic unit for calculating the sound wave and emitting the sound wave inside the soundproof room.
A sound wave generating means for raw, soundproofing apparatus having a sound wave generator on the sliding portion of the installed sliding device soundproofing chamber.