JP3215478U - Sound barrier and sound absorbing member - Google Patents

Abstract

A soundproof wall and a sound absorbing member capable of improving sound absorbing performance are provided. A soundproof wall is disposed at a position facing the wall body and spaced apart from the wall body in an X-axis direction (first direction) perpendicular to the wall body. A sound absorbing member 1 and a space SP1 formed between the first sound absorbing member 1 and the wall 201, and a second sound absorbing member 2 disposed to face the wall 201, and a space SP1. In the inside, a gap (first gap) SP2 having a size of 10% or more with respect to the size of the space SP1 in the X-axis direction is formed between the second sound absorbing member 2 and the wall body 201. A gap (second gap) SP3 having a size of 5% or more with respect to the size of the space SP1 in the X-axis direction is formed between the second sound absorbing member 2 and the first sound absorbing member 1. Is done. [Selection] Figure 2

Description

  The present invention relates to a soundproof wall and a sound absorbing member.

  Conventionally, what was described in patent document 1 as a noise barrier is known. Patent Document 1 describes a soundproof wall for a traveling vehicle, which is a soundproof wall according to a combination of a sound absorbing member and an air layer.

Japanese Patent Laid-Open No. 11-305781

  Here, with the speeding up of the traveling vehicle and the like, there has been a demand for further suppressing the noise during traveling from leaking outside the soundproof wall. That is, it has been required to improve the sound absorption performance of the soundproof wall.

  A soundproof wall according to an embodiment of the present invention includes a wall body, a first sound absorbing member that faces the wall body and is disposed at a position spaced from the wall body in a first direction perpendicular to the wall body, A second sound absorbing member disposed opposite to the wall body in a space formed between the sound absorbing member and the wall body, and in the space, between the second sound absorbing member and the wall body. Is formed with a first gap having a size of 10% or more with respect to the size in the first direction of the space, and between the second sound absorbing member and the first sound absorbing member, A second gap having a size of 5% or more with respect to the size in the first direction is formed.

  A sound absorbing member according to an aspect of the present invention is a sound absorbing member that is applied to a soundproof wall that includes an existing sound absorbing member that faces a wall body and is disposed at a position separated from the wall body. A sound absorbing material filled inside the member, and is configured to be inserted into a space between the wall body and the existing sound absorbing member, and a through-hole through which a bolt is inserted is formed at the edge of the housing member It can be held in the space by being fixed to other members with bolts.

  According to the present invention, the sound absorbing performance of the soundproof wall can be improved.

FIG. 1 is a schematic configuration diagram of a route structure to which a soundproof wall according to the present invention is applied. FIG. 2 is a cross-sectional view of the soundproof wall. FIG. 3A is a plan view of the second sound absorbing member, and FIG. 3B is an enlarged cross-sectional view taken along line IIIb-IIIb shown in FIG. FIG. 4A is a perspective view showing a bracket that supports the first sound absorbing member, and FIG. 4B is a perspective view showing the bracket that supports the second sound absorbing member. FIG. 5A is a diagram illustrating a state when the second sound absorbing member is inserted into the space, and FIG. 5B is a diagram illustrating the second sound absorbing member after the second sound absorbing member is inserted into the space. It is a figure which shows a fixed mode. It is a graph which shows the measurement result of an Example and a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  As shown in FIG. 1, a soundproof wall 100 according to the present invention is applied to a railway route structure 200. The route structure 200 includes a bottom portion 202, a wall body 201 erected upward from an edge portion of the bottom portion 202, and a line 203 formed on the upper side of the bottom portion 202. The soundproof wall 100 is provided on the wall body 201 and absorbs noise generated when a train passes through the track 203. The application destination of the soundproof wall 100 is not limited to a train route, and may be applied to a vehicle route that floats and travels, such as a diesel railway vehicle, an automobile, or a linear motor car.

  As shown in FIG. 2, the soundproof wall 100 includes a wall body 201, a first sound absorbing member 1, and a second sound absorbing member 2. The soundproof wall 100 may be configured such that the first sound absorbing member 1 is already installed on the wall body 201 and the second sound absorbing member 2 is attached later to the existing structure. In the following explanation, XYZ coordinates are set and explained. A direction perpendicular to the wall body 201 is defined as an X-axis direction, a horizontal direction parallel to the wall body 201 is defined as a Y-axis direction, and a vertical direction is defined as a Z-axis direction. The direction away from the wall body 201 is the positive side in the X-axis direction. FIG. 2 is a cross-sectional view of the soundproof wall 100 viewed from the negative side to the positive side in the Y-axis direction. The upper side is the positive side in the Z-axis direction.

  The wall body 201 is a concrete structure. The wall body 201 rises upward at a certain height and extends along the direction in which the line 203 extends (here, the Y-axis direction).

  The first sound absorbing member 1 is a member that faces the wall body 201 and is disposed at a position separated from the wall body 201 in the X-axis direction. The first sound absorbing member 1 is a member having a function of attenuating noise generated on the line 203 side. The first sound absorbing member 1 is disposed so as to be parallel to the surface of the wall 201 (a surface extending in the YZ axis plane). A space SP <b> 1 is formed between the first sound absorbing member 1 and the wall body 201. The size of the space SP1 in the X-axis direction is “dimension L1”. The first sound absorbing member 1 includes a sound absorbing material 3, a perforated plate 4, and a frame 6. Further, the first sound absorbing member 1 is fixed to the wall body 201 via the bracket 7.

  The first sound absorbing member 1 is a panel-like member extending in the YZ axis direction. The shape of the first sound absorbing member 1 is not particularly limited, but may be a rectangular plate member having a longitudinal direction in the Y-axis direction. The first sound absorbing member 1 may be configured by supporting the sound absorbing material 3 and the perforated plate 4 with a frame 6 constituting an outer frame. The porous plate 4 is disposed on the positive side in the X-axis direction with respect to the sound absorbing material 3. The porous plate 4 has a through-hole penetrating in the thickness direction over substantially the entire surface (for example, see FIG. 4A). The sound-absorbing material 3 may be a known material having sound-absorbing characteristics, and may be a material such as glass wool or PET nonwoven fabric.

  The bracket 7 is fixed to the wall body 201 on the proximal end side, and is fixed to the first sound absorbing member 1 on the distal end side. Thereby, the bracket 7 can fix the first sound absorbing member 1 at a position separated from the wall body 201 in the X-axis direction. The bracket 7 is fixed to the upper end 6a and the lower end 6a of the frame 6, respectively. The bracket 7 may support the first sound absorbing member 1 at a plurality of locations in the Y-axis direction (see, for example, FIG. 5). In this case, a gap is provided between the brackets 7 adjacent in the Y-axis direction. For example, as shown in FIG. 4A, the bracket 7 may be an L-shaped metal fitting, and forms a piece 7a extending from the wall body 201 toward the positive side in the X-axis direction and perpendicular to the piece 7a. And a piece 7b fixed to the wall body 201. The bracket 7 is fastened to the end portion 6a of the frame 6 with a bolt on the distal end side of the piece portion 7a. The bracket 7 may be fixed to the wall body 201 via the L-shaped angle 8 (see FIG. 2).

  The second sound absorbing member 2 is a member that is disposed in a space SP <b> 1 formed between the first sound absorbing member 1 and the wall body 201 so as to face the wall body 201 and the first sound absorbing member 1. The second sound absorbing member 2 is a member having a function of attenuating noise generated on the line 203 side. The second sound absorbing member 2 can further enhance the sound absorbing performance of the soundproof wall 100 on the back side of the first sound absorbing member 1.

  As shown in FIGS. 2 and 3A, the second sound absorbing member 2 includes a housing member 17 and a sound absorbing material 16 filled in the housing member 17. The housing member 17 may be configured, for example, by sandwiching the sound absorbing material 16 with a pair of sheet members and fixing the edges of the sheet members. The sound absorbing material 16 may have a rectangular plate shape. With such a configuration, the second sound absorbing member 2 includes the main body portion 11 having the sound absorbing material 16 and the fixing portion 12 formed on the periphery of the main body portion 11.

  The main body 11 is formed in substantially the entire area of the second sound absorbing member 2 when viewed from the X-axis direction. As shown in FIG. 3B, the main body 11 may have an adhesive layer 18 such as hot melt between the housing member 17 and the sound absorbing material 16. Although the material of the accommodating member 17 is not specifically limited, For example, the nonwoven fabric and woven fabric sheets, such as a polypropylene and a polyethylene terephthalate, may be used.

  The sound absorbing material 16 may be any material as long as it has a sound absorbing performance. For example, a material constituted by a nonwoven fabric may be employed. As the sound-absorbing material 16, for example, a combination of fine fibers (hereinafter referred to as microfibers) having excellent sound-absorbing characteristics, thick fibers (hereinafter referred to as staple fibers) that maintain the shape, and thermal bonding fibers may be used. As the sound absorbing material 16, the material described in Japanese Patent No. 4571504 may be used.

  For example, representative polymers for forming the microfibers that make up the sound absorbing material 16 include polypropylene, polyethylene, polyethylene terephthalate, polyamide, and other polymers as are known in the art. These materials are also useful for forming other directly formed fibers such as melt spun fibers. Polymers useful for forming fibers from solution include polyvinyl chloride, polyacrylate, and acrylic copolymers, polystyrene, and polysulfone. Inorganic materials such as glass also form useful fibers, including fine fibers. Although many different materials are useful in forming the preferred synthetic crimped staple fibers, natural staple fibers may also be used if they are crimped. Polyester crimped staple fibers are readily available and provide useful properties. Other useful staple fibers include polyacrylates, polyolefins, polyamides, rayon, acetates and the like.

The sound absorbing performance of the second sound absorbing member 2 is not particularly limited. However, the sound absorbing performance of the second sound absorbing member 2, basis weight as the sole sound-absorbing member (mass per unit ^{area), 100g / m 2 ~3000g / m} 2, more preferably 400g ^/ m 2 ~1700g ^/ It may be about m ² .

  The fixing portion 12 is a portion that can be fixed to another member with a bolt. A through hole 13 through which the bolt is inserted is formed in the fixing portion 12. A plurality of through holes 13 are formed along the edge of the main body 11. The second sound absorbing member 2 is held at a desired position in the space SP1 by being fixed to the bracket 20 via the fixing portion 12. In the present embodiment, the through hole 13 is formed in the fixed portion 12 disposed on the upper side of the main body portion 11 and the fixed portion 12 disposed on the lower side of the main body portion 11. However, the position and number of the through holes 13 can be appropriately changed according to the position, shape, and quantity of the bracket 20. Further, the through hole 13 may be reinforced with a metal such as eyelet so that the through hole is not broken.

  With reference to FIG.4 (b), an example of a structure of the bracket 20 is demonstrated. The bracket 20 may include an L-shaped angle 21 and a back plate 22. The bracket 20 is a member that can be fixed at a predetermined position in the X-axis direction of the bracket 7. Specifically, the bracket 20 is fixed to the bracket 7 by sandwiching the bracket 7 between the L-shaped angle 21 and the back plate 22.

  The L-shaped angle 21 includes a piece portion 21 a that is fixed to the fixing portion 12 of the second sound absorbing member 2, and a piece portion 21 b that is fixed to the back plate 22. In the L-shaped angle 21, the piece 21 a extends along the YZ axis plane, and the piece 21 b extends along the XY axis plane. The back plate 22 is disposed so as to face the piece portion 21b on the side opposite to the direction in which the piece portion 21a protrudes (the direction toward the main body portion 11 side).

  At the time of assembly, the bracket 20 sandwiches the piece 7 a of the bracket 7 between the piece 21 b of the L-shaped angle 21 and the back plate 22. In this state, the bolt 31 is inserted through the through hole 26 of the back plate 22 and fastened to the screw hole 24 of the piece 21b. Thereby, the bracket 20 is fixed to the piece portion 7 a of the bracket 7. Then, the fixing portion 12 of the second sound absorbing member 2 is superimposed on the piece portion 21 a of the bracket 20. In this state, the bolt 28 is inserted through the through hole 13 of the fixing portion 12 via the washer 29 and fastened to the screw hole 23 of the piece portion 21a. Thereby, the second sound absorbing member 2 is fixed to the bracket 20. In addition, although the bracket 20 may be attached with respect to all the brackets 7, it may be attached only to some brackets 7. FIG.

  Next, the position of the second sound absorbing member 2 in the space SP1 will be described with reference to FIG. The second sound absorbing member 2 is disposed at a position separated from the first sound absorbing member 1 and separated from the wall body 201 in the space SP1. Accordingly, a gap SP <b> 2 is formed between the second sound absorbing member 2 and the wall body 201. The size of the gap SP2 in the X-axis direction is defined as “dimension L2”. A gap SP3 is formed between the second sound absorbing member 2 and the first sound absorbing member 1. The size of the gap SP3 in the X-axis direction is “dimension L3”.

  The gap SP2 may have a size of 10% or more with respect to the size of the space SP1 in the X-axis direction. That is, when the dimension L1 of the space SP1 is 100%, the dimension L2 of the gap SP2 may be 10% or more of the dimension 1. Furthermore, the dimension L2 of the gap SP2 may be 25% or more of the dimension L1, and may be 40% or more. The upper limit of the dimension L2 of the gap SP2 is not particularly limited, but is set in a range where the dimension L3 of the gap SP3 does not fall below a lower limit value described later. For example, the dimension L2 of the gap SP2 may be 80% or less or 50% or less of the dimension L1. The gap SP3 may have a size of 5% or more with respect to the size of the space SP1 in the X-axis direction. That is, when the dimension L1 of the space SP1 is 100%, the dimension L3 of the gap SP3 may be 5% or more of the dimension 1. Furthermore, the dimension L3 of the gap SP3 may be 10% or more of the dimension 1, 25% or more, or 40% or more. The upper limit of the dimension L3 of the gap SP3 is not particularly limited, but is set in a range where the dimension L2 of the gap SP2 does not fall below the above lower limit value. For example, the dimension L3 of the gap SP3 may be 80% or less or 50% or less of the dimension L1. No sound absorbing member other than the second sound absorbing member is disposed in the gaps SP2 and SP3.

  The second sound absorbing member 2 may be disposed near the center position in the X-axis direction of the space SP1. In addition, any part of the second sound absorbing member 2 may be disposed at the center position in the X-axis direction of the space SP1. Specifically, when the center axis line CL is set at the center position in the X-axis direction of the space SP1, if any part of the second sound absorbing member 2 overlaps the center axis line CL when viewed from the Y-axis direction. Good. Note that any part of the second sound absorbing member 2 may have a structure that is not disposed at the center position in the X-axis direction of the space SP1.

  In addition, the specific dimension of the X-axis direction of each structure of the soundproof wall 100 is not specifically limited. However, as an example, the dimension in the X-axis direction of the sound absorbing material 3 of the first sound absorbing member 1 may be 30 to 150 mm. The dimension in the X-axis direction of the sound absorbing material 16 of the second sound absorbing member 2 may be 5 to 50 mm. The dimension L1 in the X-axis direction of the space SP1 may be 20 to 150 mm.

  It is not particularly limited to what extent the sound absorbing material 16 of the second sound absorbing member 2 overlaps the sound absorbing material 3 of the first sound absorbing member 1 when viewed from the X-axis direction. For example, when the entire soundproof wall 100 is viewed, the sound absorbing material 16 of the second sound absorbing member 2 may overlap with an area of 20% or more of the sound absorbing material 3 of the first sound absorbing member 1, and 50% or more. And may overlap with an area of 80% or more. The sound absorbing material 16 of the second sound absorbing member 2 may overlap the entire area (that is, 100%) of the sound absorbing material 3 of the first sound absorbing member 1. Note that there may be a portion where the sound absorbing material 16 of the second sound absorbing member 2 does not overlap the sound absorbing material 3 of the first sound absorbing member 1.

  The second sound absorbing member 2 is a member that can be inserted into the space SP <b> 1 between the existing first sound absorbing member 1 and the wall body 201. That is, even if the second sound absorbing member 2 is in a state in which it is difficult to access the space SP1 because the first sound absorbing member 1 is disposed in front of the wall body 201 in advance, the second sound absorbing member 2 can enter the space SP1. It can be inserted. The state in which the second sound absorbing member 2 is “configured to be inserted into the space” includes the following state. For example, when the second sound absorbing member 2 is inserted into the space SP1 from the outside of the first sound absorbing member 1, the second sound absorbing member 2 can be interfered with the bracket 7 or the frame 6 in a fully opened state. Furthermore, it is assumed that the second sound absorbing member 2 can be inserted into the space SP1 by deforming it. When the second sound absorbing member 2 has the configuration, it may be considered that the second sound absorbing member 2 is configured to be insertable into the space SP1. The deformation may include bending the second sound absorbing member 2 partially, folding the second sound absorbing member 2 to make it compact, winding it into a roll shape, and making it compact. In addition, when the 2nd sound absorption member 2 is divided | segmented into a small member with respect to the existing 1st sound absorption member 1, it corresponds to the state comprised so that insertion to space SP1 was possible. For example, in the example of FIG. 5 described later, the second sound absorbing member 2 per piece may be configured to be smaller than the insertion gap SP4.

  For example, as shown in FIG. 5A, it is assumed that the first sound absorbing member 1 is provided in advance on a wall body 201 (not shown) and the bracket 20 is attached to the bracket 7. In this case, it is necessary to insert the second sound absorbing member 2 from the gap SP4 between the brackets 7 or the like. On the other hand, the second sound absorbing member 2 in a completely expanded state may be larger than the gap SP4 (see, for example, FIG. 5B). In such a case, as shown to Fig.5 (a), it is set as a compact state by making the 2nd sound absorption member 2 into the folding body B which folded. The folded body B has an overall shape that is easy to insert into the gap SP4. The second sound absorbing member 2 may be a roll body R as indicated by a virtual line. The folded body B is inserted from the gap SP4 and disposed in the space SP1. Thereafter, as shown in FIG. 5B, the second sound absorbing member 2 is developed in the space SP <b> 1, aligned at a desired position, and then fixed to the bracket 20. In such a case, it can be said that the second sound absorbing member 2 is configured to be insertable into the space SP1. Alternatively, the opened second sound absorbing member 2 may enter the space SP1 through the gap SP4 while appropriately bending.

  However, the procedure for assembling the second sound absorbing member 2 to the soundproof wall 100 is not limited to that shown in FIG. For example, the second sound absorbing member 2 may be attached to the wall body 201 before the first sound absorbing member 1, and then the first sound absorbing member 1 may be attached to the wall body 201.

  Next, the operation and effect of the soundproof wall 100 and the second sound absorbing member according to the present embodiment will be described.

  The soundproof wall 100 is a wall body 201 and a first sound absorbing member 1 that is disposed at a position facing the wall body 201 and spaced from the wall body 201 in the X-axis direction (first direction) perpendicular to the wall body 201. And a second sound absorbing member 2 disposed opposite to the wall 201 in the space SP1 formed between the first sound absorbing member 1 and the wall 201, and in the space SP1, A gap (first gap) SP2 having a size of 10% or more with respect to the size of the space SP1 in the X-axis direction is formed between the two sound absorbing members 2 and the wall body 201. A gap (second gap) SP3 having a size of 5% or more with respect to the size of the space SP1 in the X-axis direction is formed between the sound absorbing member 2 and the first sound absorbing member 1.

  Such a soundproof wall 100 includes a second sound absorbing member 2 disposed to face the wall body 201 in a space SP1 formed between the first sound absorbing member 1 and the wall body 201. Thus, the sound absorbing performance of the soundproof wall 100 can be improved by providing the second sound absorbing member in addition to the first sound absorbing member 1. In the space SP1, a gap SP2 having a size of 10% or more with respect to the size of the space SP1 in the X-axis direction is formed between the second sound absorbing member 2 and the wall body 201. . In the space SP1, a gap SP3 having a size of 5% or more with respect to the size of the space SP1 in the X-axis direction is formed between the second sound absorbing member 2 and the first sound absorbing member 1. Is done. Thus, the sound absorbing performance of the soundproof wall 100 can be further improved by forming the gaps SP2 and SP3 having appropriate sizes on both sides in the X-axis direction of the second sound absorbing member.

  In the soundproof wall 100, the second sound absorbing member 2 may be a member that can be inserted into the space SP <b> 1 between the existing first sound absorbing member 1 and the wall body 201. Thereby, the sound absorption performance of the soundproof wall 100 can be easily improved only by arranging the second sound absorbing member at an appropriate position with respect to the existing first sound absorbing member 1.

  In the soundproof wall 100, any portion of the second sound absorbing member 2 may be disposed at the center position in the X-axis direction of the space SP1. Thereby, the gaps SP2 and SP3 on both sides of the second sound absorbing member 2 are further appropriately sized.

  In the soundproof wall 100, the second sound absorbing member 2 includes a housing member 17 and a sound absorbing material 16 filled in the housing member 17, and other members ( Here, a fixing part 12 which can be fixed to the bracket 20) may be formed. Thereby, the 2nd sound absorption member 2 can be easily arrange | positioned in a suitable position by fixing the 2nd sound absorption member 2 with a volt | bolt in a fixing | fixed part.

  The second sound-absorbing member (sound-absorbing member) 2 is applied to the soundproof wall 100 including the first sound-absorbing member (existing sound-absorbing member) 1 facing the wall body 201 and disposed at a position separated from the wall body 201. A sound-absorbing member comprising a housing member 17 and a sound-absorbing material 16 filled in the housing member 17, and can be inserted into a space SP1 between the wall body 201 and the existing first sound-absorbing member 1. A through hole 13 through which a bolt is inserted is formed at the edge of the housing member 17 and can be held in the space SP1 by being fixed to another member (here, the bracket 20) with the bolt. It is.

  According to the second sound absorbing member 2, the same effect and effect as the above-described soundproof wall 100 can be obtained.

  The present invention is not limited to the above-described embodiment.

  For example, the structure of the soundproof wall may be changed as appropriate without departing from the spirit of the present invention. For example, the configuration of the first sound absorbing member 1 and the support structure of the first sound absorbing member 1 are not limited to the above-described embodiment, and may be changed as appropriate. Moreover, the structure of the 1st sound absorption member 1 and the support structure of the 1st sound absorption member 1 are not limited to the above-mentioned embodiment, You may change suitably.

[Example]
Next, an embodiment of the present invention will be described. However, the present invention is not limited to the following examples.

  This experiment was performed using a model that can easily measure the performance of the sound barrier. In the model, a first sound absorbing member, a second sound absorbing member, a wall, and a space are formed in a cylindrical member having an inner diameter of 40 mm. A sound absorbing material corresponding to the first sound absorbing member is arranged on one end side of the cylindrical member. A member corresponding to the wall is disposed on the other end side of the cylindrical member. Between them, a space having a length of 75 mm in the axial direction of the cylindrical member was formed.

As the sound absorbing material of the first sound absorbing member, “Synth Fiber (registered trademark)” manufactured by “TORAY” was used. The basis weight of the sound absorbing material was 2000 g / m ² , the thickness was 50 mm, and the skin material was 120 g / m ₂ . As a sound absorbing material for the second sound absorbing member, “Synsalate (registered trademark), MTI-7010” manufactured by “3M” was used. Basis weight of the sound-absorbing material is 851 g / ^{m 2,} thickness skin material is 18mm was 40 g / ^{m 2.} Aluminum metal material was used as the wall. The experiment for measuring the sound absorption performance was performed using a normal incident sound absorption measurement system “WinZac” manufactured by “Nippon Acoustic Engineering”. Specifically, the measurement was performed by the method of measuring the sound absorption coefficient and impedance using an acoustic tube in accordance with JIS1405-2.

  Using the model as described above, measurement was performed by changing the position of the second sound absorbing member in the space. A device excluding the second sound absorbing member was referred to as Comparative Example 1. Comparative Example 2 was obtained by eliminating the gap between the first sound absorbing member and the second sound absorbing member. Comparative Example 3 was obtained by eliminating the gap between the second sound absorbing member and the wall. A gap between the first sound-absorbing member and the second sound-absorbing member was 10 mm, and a gap between the second sound-absorbing member and the wall was 39 mm. A gap between the first sound absorbing member and the second sound absorbing member was set to 20 mm, and a gap between the second sound absorbing member and the wall body was set to 29 mm as Example 2. A gap between the first sound-absorbing member and the second sound-absorbing member was set to 30 mm, and a gap between the second sound-absorbing member and the wall body was set to 19 mm as Example 1.

  The measurement results are shown in FIG. In Comparative Example 1, there is a decrease in the sound absorption rate that is considered to be caused by the space between the sound absorbing member and the wall in the band near 1000 Hz. In Comparative Example 2, an improvement was observed in the band near 1000 Hz, but the decrease in the band near 500 Hz was large. In Comparative Example 3, no decrease is observed in the band near 500 Hz, but the improvement in the band near 1000 Hz is small. In Examples 1, 2 and 3, the decrease in the band near 500 Hz is small, and the improvement in the band near 1000 Hz is large. Furthermore, the sound absorption rate of 0.7 or more is maintained even in the low range up to 250 Hz. From the results, it is shown that the sound absorption characteristics are improved with respect to noise from low frequencies to around 1000 Hz. This band around 1000 Hz is a band particularly regarded as a problem in vehicle noise, and its reduction is particularly effective.

  DESCRIPTION OF SYMBOLS 1 ... 1st sound-absorbing member (existing sound-absorbing member), 2 ... 2nd sound-absorbing member, 12 ... Fixed part, 13 ... Through-hole, 16 ... Sound-absorbing material, 17 ... Housing member, 100 ... Sound-proof wall, 201 ... Wall body , SP1 ... space, SP2 ... gap (first gap), SP3 ... gap (second gap).

Claims (5)

A wall,
A first sound-absorbing member that is disposed at a position facing the wall body and spaced from the wall body in a first direction perpendicular to the wall body;
A space formed between the first sound absorbing member and the wall body, and a second sound absorbing member disposed facing the wall body,
In the space,
Between the second sound absorbing member and the wall body, a first gap having a size of 10% or more with respect to the size of the space in the first direction is formed,
A second gap having a size of 5% or more with respect to the size of the space in the first direction is formed between the second sound absorbing member and the first sound absorbing member. Sound barrier.   The soundproof wall according to claim 1, wherein the second sound absorbing member is a member that can be inserted into the space between the existing first sound absorbing member and the wall body.   The soundproof wall according to claim 1 or 2, wherein any part of the second sound absorbing member is disposed at a center position in the first direction of the space. The second sound absorbing member includes a housing member and a sound absorbing material filled in the housing member,
The soundproof wall as described in any one of Claims 1-3 in which the fixing | fixed part which can be fixed to another member with a volt | bolt is formed in the edge of the said accommodating member. A sound-absorbing member that is applied to a soundproof wall that includes an existing sound-absorbing member that is opposed to a wall body and is disposed at a position separated from the wall body,
A receiving member;
A sound-absorbing material filled in the housing member,
It is configured to be insertable into a space between the wall body and the existing sound absorbing member,
A through hole through which a bolt is inserted is formed at the edge of the housing member,
A sound absorbing member that can be held in the space by being fixed to another member with the bolt.

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