JP4878481B2 - Method for measuring sound transmission characteristics of plate - Google Patents

Description

  The present invention relates to a method for measuring sound transmission characteristics of a plate-like body.

  Conventionally, as a measurement method for accurately measuring the sound transmission characteristics indicating the air sound insulation performance (sound insulation performance) of a plate-like body, Japanese Industrial Standards JIS A1416: 2000 “Air sound insulation performance of building members in a laboratory” “Measuring method” (Non-Patent Document 1) and the like are known.

In the measurement method according to the JIS standard, a test chamber in which a sound source chamber and a sound receiving chamber are adjacent to each other through a sample mounting opening is necessary. It is necessary to make the structure so that the contribution of sound due to the sound becomes as small as possible. The volume of each chamber of the type 1 test chamber used for measuring the sound transmission loss is 100 m ³ , preferably 150 m ³ or more, and the volumes of both chambers are preferably different by 10% or more. Further, it is desirable that the area of the sample opening is approximately 10 m ² , the short side dimension is 2.3 m or more and a rectangle. When the area of the sample opening is 10 m ² or less, the sample is attached to the opening adjusting wall installed in the sample attaching opening. A sound source unit is disposed in the sound source room, and a sound receiving unit is disposed in the sound receiving room. The sound wave transmitted from the sound source unit is transmitted through the sample and received by the sound receiving unit. By analyzing the frequency of the sound wave (received sound wave) by 1/3 octave band filter processing, the sound transmission characteristic of the sample is measured, and the sound transmission loss is obtained.
Japanese Industrial Standards JIS A1416: 2000 “Measurement method of air sound insulation performance of building materials in the laboratory”

In the measurement method according to JIS A1416: 2000 (hereinafter referred to as JIS standard), when a sample with a different size is measured, it is necessary to manufacture a sample mounting opening for each sample size. Further, when changing the sample, it is necessary to remove the putty for fixing the sample, replace the sample, and fix it with the putty.
Therefore, this measurement method is suitable for accurately measuring the air sound blocking performance of building components such as window glass and building materials, but the sound transmission characteristics of the same or various products are within the intended range. In order to confirm, it is not suitable to measure the whole amount or sampling because it takes a lot of equipment and time and cost.

  However, when measuring the sound transmission characteristics of a sample without using the equipment defined in the above-mentioned JIS standard, since the sound wave transmitted from the sound source unit wraps around the sample, the sound receiving unit uses the sound wave transmitted through the sample. There is also a problem that the sound wave that goes around the sample is also received.

  The present invention has been made paying attention to such a conventional problem, and its purpose is to be able to measure the sound transmission characteristics of a sample without using a large-scale facility as defined in the above-mentioned JIS standard. Is to do.

The inventor of the present invention has studied through trial and error in order to achieve the above-mentioned object, and as a result, has found that the sound transmission characteristics can be measured without using a large-scale facility.
The method for measuring the sound transmission characteristics of the plate-like body according to claim 1 comprises:
Transmitted sound waves from the sound source unit disposed on the first main plane side of the plate-like body are transmitted through the plate-like body, and the transmitted sound waves are received on the other second main plane side of the plate-like body. A sound transmission characteristic of the plate-like body by analyzing the received sound wave,
The sound receiving portion is covered with a soundproof material having an opening, and the opening of the soundproof material is disposed in contact with the second main plane.

In claim 2, the plate-like body is
A sound insulating laminated glass composed of two glass plates and an intermediate film having a sound insulating performance sandwiched between these glass plates;
Two glass plates having the same size and the same shape as the glass plate of the sound insulating laminated glass, and a general intermediate having the same size and the same shape as the sound insulating interlayer sandwiched between the two glass plates. A normal laminated glass consisting of a film,
The predetermined center frequency in the transmitted sound wave in the step of transmitting the sound wave is a frequency at which the plate-like body exhibits a coincidence effect ,
After the step of measuring the received sound wave,
A step of discriminating between the sound insulating laminated glass and the normal laminated glass is added based on the measurement in the step of measuring the received sound wave .

  According to the present invention, sound transmission characteristics can be measured without using a large-scale facility as defined by the JIS standard described above. Then, in order to confirm that the sound transmission characteristics of the same product are within the target range, it can be measured in whole quantity or sampling. In addition, the sound transmission characteristics can be measured even in an environment where there is noise around, such as a manufacturing site.

  According to the method for measuring the sound transmission characteristics of the plate-like body according to claim 1, the sound wave transmitted around the plate-like body and the sound wave different from the sound wave (unintentional sound wave is referred to as noise). Is cut off by the soundproofing material, so that only the sound wave transmitted through the plate-like body can be measured by the sound receiving unit.

According to the method for measuring sound transmission characteristics of a plate-like body according to claim 2, since the predetermined center frequency in the transmitted sound wave is set to a frequency at which the plate-like body exhibits a coincidence effect, It is possible to perform an efficient measurement focusing on the characteristic part of the characteristic.

Next, an embodiment of the present invention will be described. However, the present invention is not limited to these.
[Measurement device for sound transmission characteristics]
FIG. 1 shows a schematic diagram of a measuring apparatus using the method for measuring sound transmission characteristics according to the present invention. In FIG. 1, the plate-like body 1 that is the object to be measured is a plate-like body curved in one direction, but a plate-like body curved in two directions, a horizontal plate-like body, and a plate-like body having uneven thickness. It is also possible to measure a relatively thick plate or the like.
The plate-like body 1 is disposed on a roller group (conveying roller) 2 constituting the conveying device. The conveyance surface formed by the conveyance roller 2 is normally adjusted to be substantially horizontal.

The sound source unit 10 includes a signal generator 11 and a speaker 12, and two objects are connected by a cable. The signal generator 11 is installed at an arbitrary position, and the speaker 12 is disposed on the first main surface 1a side (lower side of the conveyance surface) of the plate-like body 1 at an angle θ with respect to an axis perpendicular to the conveyance surface. Be placed. In FIG. 1, the installation direction of the speaker 12 is the conveyance direction (arrow A), but is not limited thereto, and the direction and position where no obstacle exists between the speaker 12 and the plate-like body 1. can do. Here, the range of the angle θ can be 0 to 90 °, that is, all directions. The range of the angle θ is preferably 40 to 90 °.

The sound receiving unit 20 includes an analyzer 21 and a microphone 22, and two objects are connected by a cable. The analyzer 21 is installed at an arbitrary position. The microphone 22 is disposed on the second main surface 1b side (upper side of the conveyance surface) of the plate-like body 1 and substantially perpendicular to the conveyance surface. The microphone 22 is covered with a soundproof material 30. The soundproof material 30 is shown in a perspective view to show the internal microphone 22. A gap 31 is formed between the tip of the microphone 22 where the sensor is located and the second main surface 1b, so that the microphone 22 does not directly contact the second main surface 1b. The microphone 22 covered with the soundproof material 30 can be moved in the direction of arrow B and in the opposite direction by an elevating mechanism (not shown).

In FIG. 2, the example of the longitudinal cross-sectional view of the soundproof material 30 shape | molded according to the shape of the microphone 22 is shown. Inside the soundproof material 30, there is a cavity 32 that substantially matches the shape of the microphone 22. Cross-sectional shape of the portion contacting the plate-like body 1 of soundproofing material 30 shown in FIG. 2 (a) is substantially flat form. By forming in this way, it can be satisfactorily adhered to a planar plate-like body. The cross-sectional shape of the portion that contacts the plate-like body of the soundproof material 30 shown in FIGS. 2B and 2C is formed in a convex shape. By forming in this way, not only a planar shape but also a curved plate-like body can be satisfactorily adhered.
The material used for the soundproof material 30 is not particularly limited as long as it has sound insulation performance. For the soundproof material 30, a material having a sponge-like structure, a material having a large number of hairs on the surface other than the portion in contact with the plate-like body, and a composite material thereof can be suitably used. A material having a sponge-like structure has an excellent soundproofing effect and can be elastically deformed, so that it can be brought into close contact with the second main surface 1b of the plate-like body 1. A material having a large number of hairs on the surface has the effect of reducing the sound caused by the wind impinging on the surface.
The soundproofing material 30 may be molded according to the shape of the microphone 22 as described above, or may be formed by forming a material having a sponge-like structure into a belt shape and winding it around the microphone 22.
The outer shape of the cross section of the soundproofing material 30 only needs to have a thickness capable of exhibiting soundproofing performance in each direction of the cross section, and a shape such as a substantially circular shape or a substantially rectangular shape is preferably used.

[Measurement procedure of sound transmission characteristics]
The procedure for measuring sound transmission characteristics is shown below.
First, the intensity of the transmitted sound wave is adjusted so that the level of the received sound wave of the microphone 22 becomes a predetermined level at a predetermined center frequency in the state where the plate-like body 1 as the object to be measured does not exist. When measuring at a plurality of center frequencies, the measurement is performed for each center frequency. This adjustment does not have to be performed every time when a plurality of plate-like bodies are continuously measured. For example, the adjustment may be performed once before the first measurement and thereafter periodically.
Next, the microphone 22 covered with the soundproof material 30 is retracted to the safe standby position in the reverse direction of the arrow B.
Next, the plate-like body 1 is carried in by the conveying roller 2 in the direction of arrow A, and is stopped at a predetermined position of the measuring device.
Next, the microphone 22 covered with the soundproof material 30 is moved in the direction of the arrow B, and the tip of the soundproof material 30 is brought into contact with the second main surface 1b.
Next, a sound wave having a predetermined center frequency is generated from the speaker 12, and the sound wave transmitted through the plate-like body 1 is received by the microphone 22. The received sound wave is sent to the analyzer 21 through the connection cable, and the sound transmission characteristic of the plate-like body 1 is measured as a transmitted sound pressure level for each frequency by performing a 1/3 octave band filter process.
If necessary, repeat the measurement for each of the multiple center frequencies.

The sound transmission characteristics of laminated glass for automobiles were measured by the method for measuring sound transmission characteristics of the present invention. Laminated glass includes laminated glass for automobiles using a general interlayer film (hereinafter referred to as “normally laminated glass”) and laminated glass for automobiles using an interlayer film having sound insulation performance (hereinafter referred to as “sound insulating laminated glass”). And manufactured).
For comparison, the air sound blocking performance of the same laminated glass was measured by the measuring method described in the JIS standard.
And the example which uses the measuring method of the sound transmission characteristic of this invention for discrimination | determination of a normal laminated glass and a sound-insulating laminated glass was shown.
[Example 1]

First, the laminated glass was normally manufactured with the general manufacturing method. The two glass plates constituting the laminated glass each had a thickness of 2 mm, and a 0.76 mm thick PVB film (manufactured by Sekisui Chemical Co., Ltd., ESREC film) was used as the intermediate film.
Next, the installation angle θ of the speaker 12 was adjusted to 60 °.
Next, the transmitted sound pressure level for each frequency of the normal laminated glass was measured according to the procedure for measuring the sound transmission characteristics described above. At this time, the center frequency of the transmitted sound wave from the speaker 12 was set to 3.15 kHz, which is close to a frequency at which a single plate glass plate having a thickness of 4 mm exhibits a coincidence effect. Then, the intensity of the transmitted sound wave having this center frequency was adjusted so that the level of the received sound wave of the microphone 22 was 90 dB in the state where the plate-like body 1 was not present.

  Table 1 shows the value of the transmitted sound pressure level of the normal laminated glass analyzed in the range of 50 to 10000 Hz. Table 1 also shows the measurement results of Example 2 described later and the transmitted sound pressure level difference between the two examples.

FIG. 3 is a graph showing the difference between the transmitted sound pressure level and the transmitted sound pressure level shown in Table 1. The frequency on the horizontal axis is logarithmic. The smaller the transmitted sound pressure level, the better the sound insulation performance of the object to be measured.
From Table 1 and FIG. 3, the transmitted sound pressure level of the laminated glass usually changes rapidly from 77.8 to 35.0 dB in the frequency band of 50 to 800 Hz, and 36 in the frequency band of 1000 to 10000 Hz. It turns out that it is changing gently from .3 to 17.7 dB.
[Comparative Example 1]

  According to the measuring method prescribed | regulated to JIS specification, the sound transmission loss of the normal laminated glass manufactured in Example 1 was measured. Table 2 shows the sound transmission loss of the normal laminated glass analyzed in the range of 50 to 10000 Hz. Table 2 also shows the sound transmission loss of Comparative Example 2 described later and the sound transmission loss difference of the two comparative examples.

FIG. 4 shows a graph of the sound transmission loss and the difference in sound transmission loss shown in Table 2. The frequency on the horizontal axis is logarithmic. The greater the sound transmission loss, the better the sound insulation performance of the object to be measured.
From Table 2 and FIG. 4, the sound transmission loss of the normal laminated glass changes rapidly from 10.2 to 35.0 dB in the frequency band of 50 to 1000 Hz, and in the frequency band of 1250 to 10,000 Hz, 35. It turns out that it is changing smoothly from 8 to 49.4 dB. The distribution below about 1 kHz seems to follow the mass side.
This normal laminated glass has a frequency band in which sound transmission loss is reduced in the vicinity of 3.15 kHz, which is close to the frequency at which a single glass plate having a thickness of 4 mm equal to the total thickness of the two glass plates exhibits a coincidence effect. I understand that
[Example 2]

First, a sound-insulating laminated glass was produced in the same manner as in Example 1 except that a 0.76 mm-thick PVB film (Sekisui Chemical Co., Ltd., ESREC acoustic film) was used as the intermediate film.
Next, the transmitted sound pressure level for each frequency of the sound insulating laminated glass was measured under the same conditions as in Example 1 in accordance with the procedure for measuring the sound transmission characteristics described above.
Table 1 shows the transmitted sound pressure level of the sound insulating laminated glass analyzed in the range of 50 to 10000 Hz, and FIG. 3 shows a graph of the transmitted sound pressure level.
From Table 1 and FIG. 3, the transmitted sound pressure level of the sound insulating laminated glass is abruptly changing from 79.8 to 33.5 dB in the frequency band of 50 to 630 Hz, and in the frequency band of 800 to 10,000 Hz. It turns out that it is changing gently from 34.6 to 17.7 dB.
[Comparative Example 2]

The sound transmission loss of the sound insulating laminated glass manufactured in Example 2 was measured according to the measurement method defined in the JIS standard.
Table 2 shows the sound transmission loss analyzed in the range of 50 to 10000 Hz, and FIG. 4 shows a graph of the sound transmission loss.
From Table 2 and FIG. 4, the sound transmission loss of the sound insulating laminated glass changes rapidly from 14.5 to 35.5 dB in the frequency band of 50 to 1000 Hz, and is 36 in the frequency band of 1250 to 10000 Hz. It turns out that it is changing gently from 3 to 47.6 dB. As in Comparative Example 1, the distribution of about 1 kHz or less seems to follow the mass side.
It can be seen that the laminated glass for automobiles using the interlayer film having the sound insulation performance has a frequency band in which sound transmission loss is reduced in the vicinity of 6.3 kHz, not in the vicinity of 3.15 kHz described above.

(Comparison of measurement methods)
From the graph of the measurement results obtained by the accurate measurement method stipulated in the JIS standard shown in FIG. 4, it can be seen that there is a difference in sound transmission loss between the normal laminated glass and the sound insulating laminated glass in the frequency band of 1000 to 10000 Hz. . And a frequency band of 1000 to 5000 Hz including a frequency (around 3.15 kHz) showing a coincidence effect of a laminated glass manufactured by combining two glass plates having a thickness of 2 mm and an interlayer film having a thickness of 0.76 mm. It can be seen that the sound transmission loss of the sound insulating laminated glass is large. In other words, it can be seen that this sound insulating laminated glass is superior in sound insulating performance to normal laminated glass in a frequency band of 5 kHz or less that humans are sensitive to.

Comparing FIG. 3 and FIG. 4, it can be seen that the tendency of the measurement results does not completely match between the sound transmission characteristic measurement method according to the present invention and the accurate measurement method defined in the JIS standard. However, also in the method for measuring sound transmission characteristics according to the present invention, it can be seen that the sound insulating laminated glass is superior in sound insulating performance to the normal laminated glass in the frequency band of 1000 to 5000 Hz.
In other words, when focusing on the frequency band in which the plate-like object to be measured has a characteristic distribution, the accurate measurement method defined in the JIS standard can be obtained by using the sound transmission characteristic measurement method according to the present invention. The sound transmission performance of the plate-like body can be determined without using it.
Below, the Example which used the measuring method of the sound transmission characteristic of this invention for discrimination with normal laminated glass and sound-insulating laminated glass is shown.
[Example 3]

From the results of Example 1 and Example 2, the transmitted sound pressure levels of the normal laminated glass and the sound insulating laminated glass at a frequency of 3.15 kHz were 36.6 dB and 26.1 dB, respectively. 31 dB was set as a threshold with reference to 31.35 dB.
100 sheets of normal laminated glass and sound insulating laminated glass having the same size and shape were prepared. Each laminated glass was given an identification mark. The sound transmission characteristics of two types of laminated glass were measured using the measurement apparatus shown in FIG. When the transmitted sound pressure level at a frequency of 3.15 kHz was equal to or less than the threshold value 31 dB, the laminated glass was determined to be sound-insulating laminated glass, and the others were determined to be normal laminated glass and distributed to separate glass carts.
When the identification mark attached to the laminated glass of each carriage was confirmed, it was confirmed that the normal laminated glass and the sound insulating laminated glass were correctly distributed without being erroneously determined.
Therefore, it was found that the presence or absence of sound insulation performance can be determined in the production line inspection process. It was also found that it is possible to inspect whether the sound insulation performance of the sound insulation laminated glass satisfies the standard.

It is the schematic of the measuring apparatus using the measuring method of the sound transmission characteristic in this invention. It is sectional drawing which shows the example of the shape of the soundproof material used for the measuring method of the sound transmission characteristic in this invention. It is a figure showing the graph of distribution of the transmitted sound pressure level with respect to the frequency of the laminated glass measured by the measuring method of the sound transmission characteristic in this invention. It is a figure showing the graph of distribution of the sound transmission loss with respect to the frequency of the laminated glass measured according to the measuring method prescribed | regulated to JISA1416: 2000.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plate-shaped body 1a 1st main plane 1b of a plate-shaped body 2nd main plane 2 of a plate-shaped body 2 Conveyance roller 10 Sound source part 11 Signal generator 12 Speaker 20 Sound receiving part 21 Analyzer 22 Microphone 30 Soundproof material 31 Crevice 32 Cavity

Claims (2)

A method for measuring sound transmission characteristics of a plate- like body,
A step of retracting the sound receiving portion covered with the soundproofing material to a standby position;
A step of carrying in the plate-like body by a conveying device;
A step of stopping the loaded plate-like body at a predetermined position;
Moving the soundproof material toward the plate-shaped body, and bringing the tip of the soundproof material into contact with the plate-shaped body;
Transmitting sound waves from a sound source unit disposed on the first main plane side of the plate-like body;
And transmitting the transmitted sound wave through the plate-like body, receiving the transmitted sound wave at a sound receiving portion disposed on the other second main plane side of the plate-like body, and measuring the received sound wave. A method for measuring sound transmission characteristics of a plate-like body. The plate-like body is
A sound insulating laminated glass composed of two glass plates and an intermediate film having a sound insulating performance sandwiched between these glass plates;
Two glass plates having the same size and the same shape as the glass plate of the sound insulating laminated glass, and a general intermediate having the same size and the same shape as the sound insulating interlayer sandwiched between the two glass plates. A normal laminated glass consisting of a film,
The predetermined center frequency in the transmitted sound wave in the step of transmitting the sound wave is a frequency at which the plate-like body exhibits a coincidence effect ,
After the step of measuring the received sound wave,
Based on the measurement in the step of measuring the reception waves, the sound transmission characteristics of claim 1, wherein the plate-like body, characterized in that the addition of steps for distinguishing between the ordinary laminated glass and the sound insulation laminated glass Measuring method.

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