JPS6010037A - sound insulation structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound insulation structure having an acoustically multi-walled structure with improved sound insulation performance.

In recent years, in order to deal with problems such as residential noise, research and development of many sound insulation technologies and materials have been carried out. Furthermore, in building materials, improvements in construction performance are being sought. In other words, resource saving and
In order to save energy and improve safety, insulation, weight reduction, and non-combustibility are required, and thinner structures are being sought to expand space and improve workability. For this reason, sound insulating materials and sound insulating structures that meet these requirements have also been sought. However, the improvement in the sound insulation performance of Kengetsu or Kenyanmono-5 and the above-mentioned required performance are often at odds with each other, and it has been difficult to achieve both.

Generally, the sound insulation performance of sound insulation materials is I°'.

The sound transmission loss is approximately determined based on the IMf11 rule for sound transmission, and indicates the sound insulation performance.
onLoss (hereinafter referred to as T, T, etc.) improves as the areal density increases. Also, T and L are larger than the mass side.
.

In order to improve the sound insulation effect, it is common to use a double wall or multi-wall structure in which sound insulation materials are arranged in parallel, and to further improve the sound insulation effect by inserting a sound absorbing material or the like inside. However, such a method inevitably results in an increase in weight and thickness. In addition, a particular problem is that even if such a method is used, there are still many cases in which a significant decrease in T and L, that is, a sound insulation defect occurs in a specific sound range due to the coincidence effect and resonance transmission in the low range. A common method to improve this sound insulation deficiency is to change the natural frequency due to the sound insulation and structure in order to move the frequency range in which the sound insulation deficit resides out of the audible range, which is also a conventional method. This tends to cause problems such as an increase in weight and thickness, or a decrease in the rigidity of the sound insulation.

As described above, in order to achieve high sound insulation, the critical issue is how to obtain sound insulation that is greater than the mass, and how to prevent deterioration due to lack of sound insulation. Currently, double walls or multi-walls are constructed using walls with a large area density similar to those of the North Koreans (including structural walls), and sound absorbing materials such as glass wool and rock wool are inserted inside to reduce sound insulation defects. The allowances are generally T.

Either adopt a larger L, or reduce the sound insulation loss from the beginning within the audible frequency range (e.g. 125-4000Hz).
) In many cases, the design and construction are done without considering a significant increase in thickness or weight to prevent this from occurring. In addition, as other countermeasures against sound insulation defects, insertion of high-performance sound absorbers 42 and distribution treatment of face materials are also carried out, but these are expensive and often do not have sufficient effects.

The present invention realizes a method of suppressing the deterioration of sound insulation performance due to sound insulation defects as much as possible, and achieves the maximum sound insulation performance that can be obtained by the mass side almost all the time in the 1-frequency range. This is to maximize the increase in T and L due to multi-wall construction.

The present inventor has discovered that when a sound insulation structure is constructed from area parts of multiple areas with different areal densities and solid vibration frequencies in the sound insulation direction, the sound transmission loss decreases due to the coincidence effect, and the transmission due to resonance transmission in the low frequency range. They discovered that the drop in loss was significantly improved and completed the present invention.

The above phenomenon occurs when sound is almost uniformly incident on the entire surface of a structure, evenly or completely randomly, and despite receiving uniform air excitation, the areal density of the blades making up the structure Each part of the enclosure with a different natural frequency behaves differently from the other parts, and as a result, the components of the transmitted sound from each part are moderately different, so the synthesized sound after passing through is adjusted to eliminate harmful effects. transmitted sound,
In other words, it is thought that the sound in a specific frequency range is reduced due to sound insulation defects.

The sound insulation structure according to the present invention has a multi-wall structure in terms of acoustics, and the plate blades constituting the structure have an areal density of +
11, the plurality of areas are configured such that the ratio of the maximum value to the minimum value of the average areal density depth in each area is 1.2 or more, and the area has a difference of 1.2 or more in the average area density. The structure is formed such that the sum of the areas of the large area and the area of the area covers 25% or more of the total area of the root, and the structure is perpendicular to the sound transmission. It is composed of a plurality of structural regions having different natural frequencies in different directions, and the natural frequency fr of each of the plurality of structural regions is
A region where fr is large in a region where the ratio of the maximum value to the minimum value of is 1.1 or more, and the ratio of the rr is different by 1.1 or more,
The sum of the cross-sectional areas of each of the small areas of fr in a vertical cross-section perpendicular to the sound transmission direction accounts for 25% or more of the total cross-sectional area in the vertical cross-section of the structure, and the size of fr in the vertical cross-section is The structure is characterized in that the average of the diameters of the maximum circles included in each of the region of 1 and the region of fr is larger than the thickness of the structure.

That is, the structure has multiple fHH'f with different natural frequencies.
It is composed of I or each region has a different acoustic i.
The planar densities m of the plates are different so that they can move, and in order to suppress the level of transmitted sound due to sound insulation defects, the sound insulation defect frequencies of each part of the area are appropriately separated, and the transmitted energy is also reduced to a level corresponding to the area of each part. By doing so, it is possible to disperse and equalize sound insulation defects.

In the case of sound insulation defects, T and L are caused by the coincidence effect.

T due to the drop in and resonance transmission in the bass range.

The drop in L is particularly problematic. In order to solve these problems, we investigated the conditions of the plate materials and structures that make up the structure, and arrived at the present invention.

First, the plate material is composed of a plurality of regions having different areal densities n1. By varying the areal density of each region,
This is because the sound insulation loss frequencies in each part of the region can be appropriately dispersed and leveled. Therefore, as the natural frequency of the panel, the following f rmd can be considered as the main G. This is because countermeasures against f rmd at other higher-order solid frequencies exhibit similar effects.

Further, the coincidence limit frequency fc is expressed by the following equation.

fc = (c"/2π)X (m/'B)" (however,
(C is the surface density when the sound velocity is 1 m, and B is the stiffness.) In order to improve the sound insulation deficiency near fc by leveling or dispersing it, the ratio of the maximum value of fc and the maximum /11 value of the plate material in each area must be 1.
It is necessary that they differ by 1 or more. That is, if the bending rigidity of the plate material is -5 in each region, the areal density ratio needs to be 1.2 or more from the above equation. Therefore, it is necessary to set the ratio of the maximum value to the minimum value of the average areal density 111 of each region to be 1.2 or more. This is because if this ratio is less than 1.2, the effect of dispersing and leveling T, T, in the coincidence limit frequency region becomes poor.

Next, the sum of the areas of each of the 111 large regions and the region of /lX of m in the regions where the average surface density m differs by 1.2 or more is 25% or more, preferably 40% or more of the total area of the plate material. It is necessary to form the plate 42 so as to have the following values. If each is less than 25%, even if the areal density is increased to increase the mass law component T - TJ, the effects of dispersion and leveling in the coincidence limit frequency region described above cannot be obtained. be.

Although the sound insulation structure according to the present invention is formed using a plate material that satisfies the above conditions, the structure also needs to satisfy certain conditions. In other words, the structure has a plurality of structural regions having different natural frequencies, such as by using a plate material that is perpendicular to the sound transmission direction and eliminates the non-homogeneous region. be done. It is necessary that the ratio between the maximum value and the minimum value of the solid U frequency fr of each of the plurality of structural regions is 1.1 or more. This is because, unless the ratio of natural frequencies is δ1 by 161 or more, T for each I/3 octave band is
.

This is because the leveling of the 51 curve cannot be expected and therefore the sound insulation deficiency cannot be improved.

Next, in order to equalize or disperse sound insulation defects caused by resonance transmission in the low frequency range, for example, if the structure is a double wall, the resonance transmission frequency f rmd in the low frequency range is f r+
nd = (1/2π) X [(L/In -1-L
/ln')X(ρc/d)koA. However, m and +rf are the areal density of each plate material,
ρ is the density inside the structure (if a breathable material is used, it can be considered as air) + C is the speed of sound, and d is the thickness inside the structure. The fc and f r+nd can be calculated as a part of the rigid body per unit width for each area. In addition, in order to exhibit acoustic behavior that meets the purpose of the present invention, it is necessary to set f rnul to a value different by 1.1 or more from the above f
Large value of r+od (f within r+nt and small value (f
Each region showing the rnul has a minimum required area. This area is referred to as the critical area, but
This critical area differs depending on the type of plate 2 and the structure of the structure. For example, if the stiffness 1f1 of the plate is small,
The smaller the thickness of the structure, the smaller the critical area will generally be.

However, regardless of the type of plate material or the structure of the structure, in the present invention, f rmd+ and f ri
It is necessary that the sum of the areas of regions having d- or more than the critical area each account for 25% or more of the total area of the entire structure. If it is less than 25%, the effect is poor, so it is preferable that it accounts for 40% or more. By this measure, improvements such as flat filling can be made for each higher-order fr at the same time. That is, as described above, frmd is the resonant transmission frequency in the low range of fr, and an improvement in frmd immediately results in an improvement in fr. Note that it is even more effective to use a structure that spatially partitions the inside of the plate materials, and in this case, it is desirable to install the partitions at the boundaries where the surface densities of the plate parts differ. Further, the lower the rigidity of the plate member, the more advantageous it is.

Even if the area occupied by a single region of the f r+nd" or frmd- is greater than or equal to the critical area, its acoustic behavior is W
In a cross section perpendicular to the direction in which sound passes through the structure, which is dominated by the shape of the t-region, it is inappropriate for the cross-sectional shape of the region to be, for example, a frame-like shape or a comb-like shape. The critical area that takes this shape into consideration is the maximum circle included in the cross-sectional area in the vertical cross section, that is, the area that touches the contour surrounded by straight lines and curves at two or more points, and the total area is within the area. It turns out that it is best to represent it with the largest circle included. Assuming that the diameter of the maximum enclosed circle is dll, as a result of experiments with various shapes, it is necessary that dm is larger than the thickness of the sound insulation structure, and if the structure is made of a rigid material, dm is the thickness. Preferably, the diameter is three times or more. This is because if dm is smaller than the thickness of the structure, the effects of dispersion and leveling in the resonance transmission frequency region of the bass range described above will be poor. Further, there is a limit to the size of a sound insulating structure due to manufacturing, construction, etc., and therefore it is practical to limit dm to 3 m or less.

Note that when there are a plurality of regions with substantially equal frmd+ or frmd-, the average diameter of the largest circle included in each region may satisfy the above condition. Further, regarding the shape of each region, a thin notch that is acoustically tasteless or a region parallel to each other with a narrow interval can be considered to be the same region, ignoring the notch or the interval.

As a method of changing the f rmd of each region of the sound insulation structure, there is a method of changing the density when the cross-sectional shape of the structure is constant. Further, the cross-sectional shape may be modified. Furthermore, regarding the above two methods, f rnul” or f ri
The regions of d- may be integrated together, or
It may be separated.

In structures where a board is partially laminated with another board,
It has been found that even if the laminated region is only partial, the sparse n1 law is applied in all frequency ranges other than the coincidence limit frequency fc. Therefore, it is presumed that in any case, the increase in areal density of the structure constructed by the above-described method will be contributed by the quality rule.

Next, an example of the structure of the sound insulation structure according to the present invention is shown in FIG.
Show G+. These are examples and do not limit the invention. A is filled with sound absorbing material 3 between the plates 1 and 2,
The lower part of the plate is thicker than the upper part, and B has an intermediate plate 4 inserted between the double walls to change the double density of this plate. C is a case where one side of the planar density of the double wall board is much smaller than the other, for example, one is a soft sound insulation material (m = 2) and the other is a gypsum board (m =
In cases such as 10), in which the lower half of the lower half with the lower areal density is laminated on two sides, it is more effective to laminate the lower half with the lower areal density as shown by the frmd formula. D is a structure in which another sound insulating material, for example, a soft sound insulating material 5, is laminated on the lower half of one side of the double wall.

I-wax has a horizontal partition 6 in the middle of the double wall, and the lower half of the right board is thicker. F is a double wall, with a horizontal partition in the middle, the lower half of the rigid board on one side is double laminated, the surface material on the other side is a soft backing material 5, and the lower half is double laminated. In addition to being heavily laminated, the type of absorption and ablation in the upper and lower parts is different. G is the case where a partition 6 is provided horizontally in the middle of the double wall, and several heavy blocks 7 are added to the upper one-sided board instead of being uniformly laminated. Further, although not shown, a plate member formed with a continuous slope from one end to the other end may naturally be used in the present invention.

In the sound insulation structure according to the present invention, for example, the plate material is on the upper side [whatever the shape of the structure as shown in this example,
It may also be inserted as a surface layer or as an intermediate layer inside. Furthermore, when the sound insulating structure of the present invention is joined to a beam, etc., the joined part should be placed at the boundary 5 of the area. ! The effect is excellent when layered with JA, and when a soft Y'i JA material is used on one side of the surface, a secondary effect is added to -'J (J). However, if it is bonded to a rigid material such as a soft material, the acoustic behavior of the surface (increased rigidity) in this area is likely to be affected, so it is advantageous to be soft. It is clear that the sound insulation structure according to 1vJ may be not only a flat plate but also a curved jnI plate or a plate-shaped body having a curved surface in part.

The sound insulation structure according to the present invention can improve sound insulation defects caused by coincidence effects by leveling and distributing them, without increasing weight or thickness, and can also disperse sound insulation defects caused by resonance transmission, especially in the low frequency range. Since the sound insulation level is improved by equalizing or leveling, it is possible to significantly improve the sound insulation grade, which has conventionally been greatly affected by these sound insulation deficiencies.

Hereinafter, the present invention will be described in further detail with regard to Examples and Comparative Examples.
I will explain this.

Example 1.2 and Comparative Examples 1 and 2 90 cm x 240 cm x 3.8 cm (
Iron powder was added to soft vinyl chloride in the same area between two silicic asbestos plates with a surface density of 4.5 kg/m2 (thickness) and a surface density of 2.1 kg/m2. Thickness h O-6m
Glass wool with a thickness of 25 mm (80K) is laminated in the same area onto a composite board made by sandwiching M and Silc sound insulation sheets (manufactured by Zeon Kasei Co., Ltd., product name Sandum 5-5). The above-mentioned soft sound insulation sheet 1- was further laminated on the surface to create a panel A (comparative example 1) which is a sound insulation structure.

A soft sound insulating sheet was stacked over the entire surface of the soft sound insulating sheet of panel A to form panel B (ratio example 2) by +'1.

■[Jchi9
Panel C (Example 1) was created by laminating the same soft sound insulating sheets of 0 cm x 120 cm as described above.

On the 90 cm x 120 cm soft sound insulation sheet surface of panel C, add another 90 cm x 12 piece of the same size.
Panel D (Example 2) was created by laminating soft sound insulating sheets of the same type with a thickness of 0 cm).

The areal densities of the roots and soft sound insulating sheets in Comparative Example 1 (Panel A) and Comparative Example 2 (Panel B) are the same as those of Plate 42, etc.
Ub7cV) Same U4M, (A: 2.1 kg/mQ
, +3: 4.2 kg/m2), and there is no structural region in the structure (panel) with different six-frequency frequencies, whereas in Example 1 (Panel C) and Example 2 (Panel D), The ratio of the maximum and minimum areal densities on the soft sound insulating sheet side is twice that of Example 1, and that of Example 2. t' is 3@, and the dog area and small area of areal density are each 50% of the total area.
One by one. In addition, even in the structure, the ratio of the maximum and minimum natural frequencies is 1.19 times in Example 1 and 1.19 times in Example 2.
．． The maximum and minimum vertical cross-sectional areas with respect to the sound transmission direction are 50% of the total vertical cross-sectional area, and the diameter of each maximum circle is 90 cm. (1α2 or 10.8 cm in Example 1 and 10.2 or 11-4 crn in Example 2).

Sound transmission loss was measured for panels A, B, C, and DG shown in Comparative Example 1.2 and Example 1.2. The measurement method is reverberation AX based on JIS-A-1416.
Based on the sound object transmission loss measurement method.

The measurement results are shown in Figure 2. As shown in the figure, panel A (indicated by the dotted line) shows a significant drop in transmission loss around 250 J-1z, and panel B (indicated by the broken line) also shows a significant drop in transmission loss around 125 J-1z.
A similar large drop is seen around ~200 Hz, whereas panel O (indicated by the dashed line) shows the frequency around 125-250 Hz.
There has been a considerable improvement in the decline in the area around T.
In panel DC (indicated by the solid line), there is a significant improvement over 1) the drop in ij. As can be seen from this figure, in the sound insulation structure according to the present invention according to Examples 1 and 2, the drop in transmission loss at fc is dispersed and leveled out as a result of the synthesis of transmitted sound from regions with different acoustic behaviors. Moreover, it can be seen that in almost all frequency ranges other than fc, a contribution based on the quality law due to an increase in areal density is obtained, and a significant improvement in transmission loss is achieved.

16. As shown in Examples 1 and 2, the heterogeneous structure of the sound insulation structure according to the present invention has been experimentally shown to be more effective in lightweight board materials than in 8U board materials. It was done.

[Brief explanation of the drawing]

Figures 1A to 1G are cross-sectional views showing examples of the structure of the sound insulation groove 1 of the present invention, and Figure 2 shows the relationship between sound transmission loss (clB) and center frequency (IIz) in the example and comparative example. It is a drawing. 1.2...Plate material, 3...Sound absorbing material. 4...Intermediate board, 5...Soft sound insulation board. 6...Partition, 7...Block. Patent issuer: Nippon Zeon Co., Ltd. Agent Patent attorney: Keiji Matsunaga Figure 1 A B D CE F Figure 2 + 25 250 500 Center frequency (TTZ)

Claims (1)

[Claims] 1. A sound insulating structure consisting of a multi-wall structure, in which the pseudophase constituting the structure consists of a plurality of regions with different areal densities m, and the maximum value of the average areal density m in each region of the Mll region. and the smallest value is 1.2 or more, and the sum of the area of each of the large area of m and the small area of 1m in the area where m is different by L2 or more of 1n is 2 of the total area of the root blade.
5% or more, and the structure has a plurality of structural regions having different natural frequencies in a direction perpendicular to sound transmission, and each of the plurality of structural regions has a The ratio of the maximum value to the minimum value of the natural frequency f] is 1.1 or more, and the ratio of fr differs by 1.1 or more, and each of the regions where fr is large and fr is small The sum of the respective cross-sectional areas in the vertical cross-section perpendicular to the sound transmission direction is 25% of the total cross-sectional area in the vertical cross-section of the structure.
% or more, and the average diameter of the maximum circle included in each of the large fr region and the lJl region of fr in the vertical cross section is larger than the thickness of the structure. body.