Soundproof structures and walls

Abstract

To provide a soundproof structure that can effectively reduce noise from a noise source side on a sound receiving side.SOLUTION: There is provided a soundproof structure 12 installed in a wall body 11 that separates space into a noise source side and a sound receiving side to reduce noise on the sound receiving side, which comprises: a plurality of acoustic tubes (a noise source side acoustic tube 121, and a sound receiving side acoustic tube 122) installed along the upper edge of the wall body 11; and an external sound absorbing member 123 on a surface facing the noise source side in the noise side acoustic tube 121.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a soundproof structure that is provided in a wall that separates a noise source side from a sound receiving side and that reduces noise on the sound receiving side, and to a soundproof wall that includes such a soundproof structure. [Background technology]

[0002] Conventionally, soundproof walls installed along railway tracks or expressways are known (see, for example, Patent Document 1). These soundproof walls are constructed with multiple acoustic tubes along the upper edge of a wall separating a noise source side (such as the railway or road) from a sound-receiving side (such as the human living area). Each acoustic tube is set to a length that is an odd multiple of a quarter wavelength of the expected noise. The upper edge of a soundproof wall constructed in this manner has an acoustically soft surface structure (soft edge) due to the multiple acoustic tubes, and sound pressure at the upward-facing openings of each acoustic tube is reduced during resonance. By providing an acoustically soft surface structure on the upper edge of the wall, a soundproof wall with a high soundproofing effect can be achieved while keeping the overall height low. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-37342 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the frequency components of noise emitted simultaneously from many vehicles (noise sources) traveling on a highway (noise source side) and from vehicles (noise sources) traveling on railway tracks (noise source side) are not constant. For this reason, it is difficult to effectively reduce actual noise using sound barriers that use multiple acoustic tubes designed according to the expected frequency components of noise.

[0005] The present invention has been made in view of the above circumstances, and provides a soundproof structure that can effectively reduce noise from the noise source side on the sound receiving side.

[0006] The present invention also provides a soundproof wall using such a soundproof structure. [Means for solving the problem]

[0007] The soundproof structure according to the present invention is a soundproof structure provided in a wall separating a noise source side from a sound receiving side, and designed to reduce noise on the sound receiving side, and includes a plurality of acoustic tubes provided along the upper edge of the wall, and external sound absorbing members provided on the surfaces of the plurality of acoustic tubes facing the noise source side. The plurality of acoustic tubes include a noise source-side acoustic tube arranged on the noise source side of the wall body and a sound receiving-side acoustic tube arranged on the sound receiving side of the wall body, and the plurality of acoustic tubes gradually become thinner in a direction from the noise source side to the sound receiving side, and the outer surface sound absorbing member is provided on the thickest noise source-side acoustic tube. , and the composition is as follows.

[0008] With this structure, noise from the noise source is transmitted to the sound receiving side while being blocked by the wall, absorbed by the external sound-absorbing material, and subjected to sound pressure reduction by the acoustically soft surface structure of the multiple acoustic tubes. In particular, on the noise side of the wall, the noise propagates to the sound receiving side while being subjected to the sound pressure reduction effect of the acoustically soft surface structure of the noise source side acoustic tube, and also to the sound pressure reduction effect of the outer surface sound absorbing member provided on the surface facing away from the wall of the thickest noise source side acoustic tube located closest to the noise source, and on the sound receiving side of the wall, the noise propagates while being subjected to the sound pressure reduction effect of the acoustically soft surface structure of the sound receiving side acoustic tube.

[0013] In the soundproof structure of the present invention, the multiple acoustic tubes can be configured to gradually become shorter in the direction from the noise source side to the sound receiving side, and the external sound-absorbing member can be provided on the longest noise source-side acoustic tube.

[0014] With this structure, noise from a noise source is absorbed by the outer sound absorbing member provided on the surface of the longest noise source side acoustic tube located closest to the noise source, facing away from the wall body, at the noise source side of the wall body. reduction be affected.

[0015] The soundproof structure according to the present invention may be configured to have a closing sound absorbing member that closes the upward opening of each of the plurality of acoustic tubes.

[0016] With this configuration, noise that has been subjected to sound absorption and transmitted through the closed sound-absorbing member is subjected to sound pressure reduction by the acoustically soft surface structure of the multiple acoustic tubes.

[0017] The soundproof structure according to the present invention may have an upper end sound absorbing member provided on the upper end surface of the wall body.

[0018] With this configuration, noise from the noise source is transmitted to the sound receiving side while being blocked by the wall, absorbed by the outer sound absorbing member and the upper end sound absorbing member, and subjected to sound pressure reduction by the acoustically soft surface structure of the multiple acoustic tubes.

[0019] In the soundproof structure according to the present invention, the thickness of the upper sound-absorbing member may be greater than the thickness of the outer sound-absorbing member.

[0020] This configuration makes it possible to more effectively absorb noise that attempts to pass over the upper edge of the wall from the noise source side.

[0021] The soundproof structure according to the present invention may have an internal sound-absorbing member filled in each of the plurality of acoustic tubes.

[0022] With this configuration, noise reduced by the sound absorbing action of the internal sound absorbing member is subjected to the sound pressure reducing action of the acoustically soft surface structure of each of the multiple sound tubes.

[0023] The soundproof wall according to the present invention has a wall body separating a noise source side from a sound receiving side, and any of the above-described soundproof structures provided on the wall body. [Effects of the Invention]

[0024] According to the soundproof structure and soundproof wall of the present invention, noise from the noise source side is transmitted to the sound receiving side while being blocked by the wall body, absorbed by the external sound absorbing material, and subjected to the sound pressure reducing effect of the acoustically soft surface structure of the multiple acoustic tubes, so that the noise from the noise source side can be effectively reduced on the sound receiving side. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a perspective view partially showing a soundproof wall according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing a soundproof wall according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a plan view showing the soundproof wall according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view partially showing a soundproof wall according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view showing a soundproof wall according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing a soundproof wall according to a third embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view showing a soundproof wall according to a fourth embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing the positional relationship between the soundproof wall, the sound source, and the eight evaluation points in the evaluation test (computer simulation). [Figure 9] FIG. 9 is a table showing the evaluation test results of each soundproof wall. [Figure 10] FIG. 10 is a diagram showing the evaluation test results at the evaluation point P1 of each soundproof wall. [Figure 11] FIG. 11 is a diagram showing the evaluation test results at the evaluation point P2 of each soundproof wall. [Figure 12] FIG. 12 is a diagram showing the evaluation test results at the evaluation point P3 of each soundproof wall. [Figure 13] FIG. 13 is a diagram showing the evaluation test results at the evaluation point P4 of each soundproof wall. [Figure 14] FIG. 14 is a diagram showing the evaluation test results for each soundproof wall at evaluation point P5. [Figure 15] FIG. 15 is a diagram showing the evaluation test results at the evaluation point P6 of each soundproof wall. [Figure 16] FIG. 16 is a diagram showing the evaluation test results at the evaluation point P7 of each soundproof wall. [Figure 17] FIG. 17 is a diagram showing the evaluation test results at the evaluation point P8 of each soundproof wall. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] The soundproof wall according to the first embodiment of the present invention is shown in FIG. 1 It is configured as shown in Figure 3. Figure 1 is a perspective view showing a part of the soundproof wall, Figure 2 is a cross-sectional view showing the soundproof wall (a cross-section in the AA direction on the S plane in Figure 1, a cross-section in the BB direction in Figure 3), and Figure 3 is a plan view showing the soundproof wall.

[0028] 1 and 2, a soundproof wall 10 has a structure in which a soundproof structure 12 is provided on a wall 11 that separates a noise source side, such as a highway, from a sound-receiving side, which is the living area of ​​people beside the highway. The wall 11 is composed of multiple support columns 111a, 111b, etc., erected at predetermined intervals along the side of the highway, and panels 112a (112b, etc.) sandwiched and fixed between two adjacent support columns 111a, 111b (see FIG. 1). The soundproof structure 12 has multiple acoustic tubes 121, 122 provided along the upper edge of the wall 11. The multiple acoustic tubes have an acoustically soft surface structure (soft edge) and include multiple noise-source-side acoustic tubes 121 arranged in a row along the noise-source-side surface of the wall 11 and multiple sound-receiving-side acoustic tubes 122 arranged in three rows along the sound-receiving-side surface of the wall 11. The plurality of sound-receiving-side acoustic tubes 122 specifically include a plurality of first-row sound-receiving-side acoustic tubes 122a, a plurality of second-row sound-receiving-side acoustic tubes 122b, and a plurality of third-row sound-receiving-side acoustic tubes 122c, which are arranged in order in a direction away from the wall body 11. Each of the plurality of noise-source-side acoustic tubes 121 and the plurality of sound-receiving-side acoustic tubes 122 (122a, 122b, 122c) is formed as a rectangular tube body that is closed at the bottom and opens upward.

[0029] In the following, the noise source side acoustic tube 121 and the receiving side acoustic tube 122 (first row receiving side acoustic tube 122a, second row receiving side acoustic tube 122b, third row receiving side acoustic tube 122c) will be referred to in the singular unless it is particularly necessary to treat them as "plural."

[0030] The multiple acoustic tubes (noise source-side acoustic tube 121, sound receiving-side acoustic tube 122) gradually become thinner in the direction from the noise source side to the sound receiving side, with the noise source-side acoustic tube 121 being the thickest, followed by the first-row sound receiving-side acoustic tube 122a, the second-row sound receiving-side acoustic tube 122b, and the third-row sound receiving-side acoustic tube 122c (see Figures 2 and 3). Furthermore, the multiple acoustic tubes (noise source-side acoustic tube 121, sound receiving-side acoustic tube 122) gradually become shorter (shallower) in the direction from the noise source side to the sound receiving side, with the noise source-side acoustic tube 121 being the longest, followed by the first-row sound receiving-side acoustic tube 122a, the second-row sound receiving-side acoustic tube 122b, and the third-row sound receiving-side acoustic tube 122c being the shortest (see Figure 2). The length of each of the multiple acoustic tubes (noise source side acoustic tube 121, sound receiving side acoustic tube 122) is set to an odd multiple of ¼ of the wavelength of the expected noise.

[0031] For example, the length of one side of the rectangular cross section (opening) of the noise-source-side acoustic tube 121 is set to about 1.5 times the length of one side of the rectangular cross section (opening) of the first-row sound-receiving-side acoustic tube 122a, about twice the length of one side of the rectangular cross section (opening) of the second-row sound-receiving-side acoustic tube 122b, and about three times the length of one side of the rectangular cross section (opening) of the third-row sound-receiving-side acoustic tube 122c. Also, for example, the length (depth) of the noise-source-side acoustic tube 121 is set to about 1.5 times the length of the first-row sound-receiving-side acoustic tube 122a, about twice the length of the second-row sound-receiving-side acoustic tube 122b, and about three times the length of the third-row sound-receiving-side acoustic tube 122c.

[0032] The soundproof structure 12, which includes the above-described multiple acoustic tubes (the noise-source-side acoustic tube 121 and the sound-receiving-side acoustic tube 122), further includes an outer sound-absorbing member 123 provided on the surface of each of the multiple acoustic tubes facing the noise source, i.e., on the surface of the noise-source-side acoustic tube 121 facing away from the wall 11. The outer sound-absorbing member 123 can be made of a porous sound-absorbing material such as glass wool that has sound-absorbing properties. The material and thickness of the outer sound-absorbing member 123 can be determined depending on the desired sound-absorbing characteristics.

[0033] With soundproof wall 10 constructed as described above, noise from a noise source (vehicles traveling on the expressway) is shielded by wall body 11, absorbed by outer sound-absorbing member 123, and subjected to sound pressure reduction effects due to the acoustically soft surface structure of multiple sound tubes (noise-source-side sound tube 121, sound-receiving-side sound tube 122), before propagating to the sound-receiving side (the living area of ​​people beside the expressway).These multiple noise-reducing effects work together in a complex manner to reduce noise on the sound-receiving side.

[0034] A soundproof wall according to a second embodiment of the present invention is configured as shown in Figures 4 and 5. Figure 4 is a perspective view showing a part of the soundproof wall, and Figure 5 is a cross-sectional view showing the soundproof wall (cross-section in the CC direction on the S plane in Figure 4).

[0035] 4 and 5, the soundproof wall 10 according to the second embodiment has a structure that includes a wall body 11 and a soundproof structure 12, similar to the soundproof wall according to the first embodiment (see FIGS. 1, 2, and 3). The soundproof structure 12 includes a plurality of sound tubes (noise-source-side sound tube 121, sound-receiving-side sound tubes 122 (first-row sound-receiving-side sound tube 122a, second-row sound-receiving-side sound tube 122b, and third-row sound-receiving-side sound tube 122c)) and an exterior sound-absorbing member 123 that are the same as those in the first embodiment, and also includes closed sound-absorbing members 124 and 125 that are formed of a porous sound-absorbing material such as glass wool, similar to the exterior sound-absorbing member 123. The closed sound-absorbing member 124 is arranged to block the upward-facing opening of the noise-side acoustic tube 121, and the closed sound-absorbing member 125 is arranged to block the upward-facing opening of the sound-receiving side acoustic tube 122 (the first row sound-receiving side acoustic tube 122a, the second row sound-receiving side acoustic tube 122b, and the third row sound-receiving side acoustic tube 122c).

[0036] With soundproof wall 10 constructed as described above, noise from the noise source (vehicles traveling on the expressway) is shielded by wall body 11 and absorbed by outer sound-absorbing member 123. The noise then passes through closed sound-absorbing members 124 and 125 while being subjected to the sound pressure reduction effect of the acoustically soft surface structure of the multiple sound tubes (noise-source-side sound tube 121, sound-receiving-side sound tube 122), before propagating to the sound-receiving side (the living area of ​​people beside the expressway). These multiple noise-reducing effects work together to reduce noise on the sound-receiving side.

[0037] A soundproof wall according to the third embodiment of the present invention is configured as shown in Fig. 6. Fig. 6 is a cross-sectional view showing the soundproof wall.

[0038] 6, the soundproof wall 10 according to the third embodiment has a structure including a wall body 11 and a soundproof structure 12, similar to the soundproof wall according to the first embodiment (see FIGS. 1, 2, and 3) and the soundproof wall according to the second embodiment (see FIGS. 4 and 5). The soundproof structure 12 includes a plurality of sound tubes (noise-source-side sound tube 121, sound-receiving-side sound tube 122 (first-row sound-receiving-side sound tube 122a, second-row sound-receiving-side sound tube 122b, and third-row sound-receiving-side sound tube 122c)) and outer surface sound-absorbing members 123, which have the same structure as those in the first embodiment. Furthermore, the soundproof structure 12 also includes an upper-end sound-absorbing member 126, which, like the outer surface sound-absorbing member 123, is made of a porous sound-absorbing material such as glass wool. The upper-end sound-absorbing member 126 is provided on the upper end surface of the wall body 11. The thickness of this upper end sound absorbing member 126 is greater than the thickness of the outer surface sound absorbing member 123, and is set to, for example, about twice the thickness of the outer surface sound absorbing member 123.

[0039] With soundproof wall 10 having this structure, noise from a noise source (vehicles traveling on the expressway) propagates to the sound-receiving side (the living area of ​​people beside the expressway) while being blocked by wall body 11, absorbed by outer sound-absorbing member 123, and subjected to sound pressure reduction effects due to the acoustically soft surface structure of the multiple sound tubes (noise-source-side sound tube 121, sound-receiving-side sound tube 122), as well as sound absorption effects by upper-end sound-absorbing member 126. These multiple noise-reducing effects work together in a complex manner to reduce noise on the sound-receiving side.

[0040] A soundproof wall according to the fourth embodiment of the present invention is configured as shown in Fig. 7. Fig. 7 is a cross-sectional view showing the soundproof wall.

[0041] In Figure 7, the soundproof wall 10 according to the fourth embodiment has a structure including a wall body 11 and a soundproof structure 12, similar to the soundproof wall according to the first embodiment (see Figures 1, 2, and 3), the soundproof wall according to the second embodiment (see Figures 4 and 5), and the soundproof wall according to the third embodiment (see Figure 6). The soundproof structure 12 has a plurality of sound tubes (a noise source-side sound tube 121, a sound receiving-side sound tube 122 (a first row of sound receiving-side sound tubes 122a, a second row of sound receiving-side sound tubes 122b, and a third row of sound receiving-side sound tubes 122c) and an outer sound absorbing member 123, and also has internal sound absorbing members 127, 128a, 128b, and 128c which, like the outer sound absorbing member 123, are made of a porous sound absorbing material such as glass wool. The internal sound absorbing member 127 fills the noise-side sound tube 121, the internal sound absorbing member 128a fills the first row of sound receiving-side sound tube 122a, the internal sound absorbing member 128b fills the second row of sound receiving-side sound tube 122b, and the internal sound absorbing member 128c fills the third row of sound receiving-side sound tube 122c.

[0042] With a soundproof wall 10 having this structure, noise from a noise source (vehicles traveling on the expressway) is shielded by the wall body 11 and absorbed by the external sound-absorbing member 123. In addition, noise that is subjected to the sound absorption of the internal sound-absorbing member 127 and passes through the internal sound-absorbing member 127 is subjected to the sound pressure reduction effect of the acoustically soft mirror-surface structure of the noise-side sound tube 121. Furthermore, noise that is subjected to the sound absorption of the internal sound-absorbing members 128a, 128b, 128c and passes through the internal sound-absorbing members 127a, 127b, 127c is subjected to the sound pressure reduction effect of the acoustically soft mirror-surface structure of the first row sound-receiving-side sound-absorbing tube 122a, the second row sound-receiving-side sound-absorbing tube 122b, and the third row sound-receiving-side sound-absorbing tube 122c, before propagating to the sound-receiving side (the living area of ​​people beside the expressway). These multiple noise reduction effects work together in a composite manner to reduce noise on the sound receiving side.

[0043] Evaluation tests (computer simulations) were conducted on the soundproof walls according to the first embodiment (see FIGS. 1, 2, and 3), the second embodiment (see FIGS. 4 and 5), the third embodiment (see FIG. 6), and the fourth embodiment (see FIG. 7), as well as the soundproof wall according to the comparative example. In this evaluation test, as shown in FIG. 8, eight evaluation points P1 to P8 were set on the sound-receiving side of the soundproof wall 10, which was set at 2 m. The wall 11 was treated as a rigid wall with no transmitted sound, and the sound pressure level at each evaluation point was calculated when a pulse sound was generated from the sound source SS on the noise source side. An analysis method based on the FDTD method (finite difference time domain method) was employed. The insertion loss of each soundproof wall (comparative example, first to fourth embodiments) was calculated from the difference in sound pressure level at each evaluation point P1 to P8 compared to a soundproof wall with only the wall 11 (without the soundproof structure 12), and the soundproof walls were evaluated based on this insertion loss.

[0044] 9 to 17 show the results of the evaluation test. In FIGS. 9 to 17, "wall" (see FIG. 9) indicates a soundproof wall consisting only of a reference wall body 11, and "A" indicates a soundproof wall as a comparative example in which the soundproof structure 12 is composed of only a plurality of acoustic tubes, excluding the external sound-absorbing member 123 from the structure of the first embodiment. Also, "B" indicates a soundproof wall according to the first embodiment, "C" a soundproof wall according to the second embodiment, "D" a soundproof wall according to the third embodiment, and "E" a soundproof wall according to the fourth embodiment. The results of the evaluation test were as follows:

[0045] The soundproof walls (B, C, D, E) according to all the embodiments (first embodiment to fourth embodiment) achieved a better noise reduction effect (larger insertion loss) than the soundproof wall of comparative example A at all evaluation points P1 to P8. Furthermore, the noise reduction effect was better in the following order at all evaluation points P1 to P8: the soundproof wall according to the first embodiment (B: acoustic tube + external sound-absorbing material), the soundproof wall according to the fourth embodiment (E: acoustic tube + external sound-absorbing material + internal sound-absorbing material), the third embodiment (D: acoustic tube + external sound-absorbing material + upper-end sound-absorbing material), and the soundproof wall according to the second embodiment (C: acoustic tube + external sound-absorbing material + closed sound-absorbing material).

[0046] Although the embodiments of the present invention have been described above, each embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments described above can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments are included within the scope and spirit of the invention, and are also included in the invention described in the claims. [Industrial Applicability]

[0047] The soundproof wall according to the present invention has the effect of effectively reducing noise from the noise source side on the sound receiving side, and is useful as a soundproof wall to be installed along railway tracks or expressways. [Explanation of symbols]

[0048] 10 Soundproof Wall 11 Wall 12 Soundproofing structure 121 Noise source side acoustic tube 122 Receiving sound tube 122a 1st row sound receiving tube 122b 2nd row sound receiving side acoustic tube 122c 3rd row sound receiving side acoustic tube 123 External sound-absorbing materials 124, 125 Closed sound absorbing member 126 Upper end sound absorbing member 127, 128a, 128b, 128c Internal sound absorbing members

Claims

1. A soundproof structure provided on a wall separating a noise source side from a sound receiving side, for reducing noise on the sound receiving side, a plurality of acoustic tubes provided along the upper edge of the wall; an outer surface sound absorbing member provided on a surface of each of the plurality of acoustic tubes facing the noise source, the plurality of acoustic tubes include a noise source-side acoustic tube arranged on the noise source side of the wall body and a sound receiving-side acoustic tube arranged on the sound receiving side of the wall body, the plurality of acoustic tubes are gradually tapered in a direction from the noise source side to the sound receiving side, A soundproof structure in which the outer sound-absorbing member is provided on the thickest noise source side acoustic tube.

2. the plurality of acoustic tubes are gradually shortened in a direction from the noise source side to the sound receiving side, 2. The soundproof structure according to claim 1, wherein the outer sound absorbing member is provided on the longest noise source side acoustic pipe.

3. 2. The soundproof structure according to claim 1, further comprising a sound-absorbing member closing the upward opening of each of the plurality of sound tubes.

4. 2. The soundproof structure according to claim 1, further comprising an upper end sound absorbing member provided on an upper end surface of the wall body.

5. 5. The soundproof structure according to claim 4, wherein the thickness of said upper end sound absorbing member is greater than the thickness of said outer surface sound absorbing member.

6. 2. The soundproof structure according to claim 1, further comprising an internal sound-absorbing material filled in each of said plurality of sound tubes.

7. a wall separating the noise source side from the sound receiving side; A soundproof wall comprising: the soundproof structure according to any one of claims 1 to 6 provided on the wall body.

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