JP6321744B2 - Soundproof device for soundproof wall - Google Patents

Description

  The present invention relates to a soundproofing device (noise reduction device) attached to the top of a soundproofing wall (soundproofing wall) that prevents noise from roads, railways, factories and the like.

For example, on an elevated road with a private house in the vicinity, noise barriers that stand upright are installed on both sides of the road in order to suppress noise generated by the traveling of an automobile. At this time, in order to increase the soundproofing (soundproofing) effect, it is conceivable to raise the soundproofing wall. However, if the soundproofing wall becomes high, the prospect of the traveling vehicle becomes worse and the right of sunshine to neighboring residents is infringed. Problem arises. Noise to the neighbors is generated by diffracted sound that goes over the sound barrier and goes diagonally downward.
For this reason, conventionally, a soundproof device is attached to the top of the soundproof wall to reduce the diffraction sound and obtain a sound reduction effect. Since this soundproofing device can provide a sound reduction effect even if it is small in volume, it can reduce the deterioration of the prospects of the automobile and the sunshine problem of neighboring residents.

The conventional soundproofing device will be described with reference to FIG. 1 showing an example of the invention according to the present application. The front and rear wall plates 11 and 12 arranged in parallel in the vertical direction are attached to the top of the soundproofing wall B, and the front and back walls thereof. The basic structure includes a bottom plate 13 that closes the lower surfaces of the plates 11 and 12 and a side plate 15 that closes the side surfaces of the space S surrounded by the front and rear wall plates 11 and 12 and the bottom plate 13 (Patent Document 1, FIG. Patent Document 2, FIG. 1, Patent Document 3, FIG. 1 and the like), a partition plate that partitions the length direction of the front and rear wall plates 11 and 12 in a space S surrounded by the front and rear wall plates 11 and 12 and the bottom plate 13 17 is provided (see Patent Document 2, FIG. 1, etc.).
These soundproofing devices adopt an acoustic tube method in which the diffracted sound is taken into a space (space S) surrounded by front and rear wall plates, etc., and the energy is reduced by interfering with the sound in the space, or by Helmholtz resonance. It uses a Helmholtz resonator that reduces the energy.

JP 2002-266322 A JP 2004-183205 A JP-A-2005-290722

Each of the above soundproofing devices is effective as it is, but since a sound reduction effect appears only at a specific frequency, further improvement of the soundproofing effect is desired. Note that the “frequency” means not a single frequency but a frequency band (hereinafter the same).
This invention makes it a subject to aim at the improvement of the further sound-proof (sound reduction) effect under the above actual condition.

First, as shown in FIGS. 1 to 3, the inventor of the present application has a front wall plate (front plate) 11 and a rear wall plate (back plate) 12 in the vertical direction arranged in parallel along the length direction of the road, Soundproofing devices A1, A2, and A3 (also including A4 below) are collectively referred to as a bottom plate 13 that covers the lower surfaces of the front and rear wall plates 11 and 12, and a parallel intermediate plate 14 between the front and rear wall plates 11 and 12. .) Was produced.
The upper portion of the rear wall plate 12 is an upward inclined surface 12a toward the front wall plate 1, the lower end is continuous with the bottom plate 13, and the lower end portion of the intermediate plate 14 is inclined toward the front wall plate 11, A gap with the bottom plate 13 is provided.
When the upper portion of the rear wall plate 12 is an upward inclined surface 12a, multiple reflection in the space S between the intermediate plate 14 and the rear wall plate 12 is further performed, and wind (arrow in the figure) flows along the inclined surface 12a. Therefore, the wind pressure is not applied to the rear wall plate 12 at a right angle, and the rear wall plate 12 is not burdened. For this reason, the use range of the material becomes wide. In particular, on the road wall, the strength of the wind pressure is important because the rear wall plate 12 is located outside the road.
The upper edge of each of the front wall plate 11, the rear wall plate 12, and the intermediate plate 14 is bent inward to form a protruding piece 16.

Further, in these soundproofing devices A, the soundproofing device A1 shown in FIG. 1 is a fully closed (space space) that partitions the length direction of the front wall plate 11 in a space S surrounded by the front and rear wall plates 11, 12 and the bottom plate 13. 2 is provided, and the soundproofing device A2 shown in FIG. 2 has an opening 17a in the soundproofing device A1, with the partitioning plate 17 serving as a reinforcing frame 17 'for removing the wall (outlining). The space (cavity) S through which the incident sound passes is formed over the entire length between the side plates 15 and 15, and the soundproofing device A3 shown in FIG. 3 is located on the inner surface of the sideplates 15 and 15 in the soundproofing device A2. Is provided with a sound absorbing material 18 made of polyester fiber.
In the case of the soundproofing device A, the front and rear wall plates 11 and 12, the bottom plate 13, the intermediate plate 14, the side plate 15 and the projecting pieces 16 are made of a resin-molded plate such as acrylic or polycarbonate, an iron plate, etc., and a partition plate 17 and a reinforcing frame 17 ′. Can adopt iron plate, aluminum plate and the like.

Attached to each of the soundproofing devices A, first, a polycarbonate resin molded plate having a length l of the front wall plate 11 of 2000 mm was manufactured.
Next, the test shown in FIG. As shown in the figure, the test apparatus is provided with a noise generator S in the center of a soundproof box (upper surface opening) surrounded on all sides by a soundproof wall B having sound absorbing performance, and from the center in the width direction of one side wall B. , Microphones M are provided at intervals of 500 mm (50 cm) (P1, P2, P3, P4) in the height direction at positions separated by 1000 mm (1 m) and 2000 mm (2 m), and noise at each point (8 points) is Measured.

In this test apparatus, when the soundproof box has four sides of the soundproof box as a soundproof wall B (simple soundproof wall), and when one soundproof device A1, A2, A3 is cut off and attached to the one side wall by the height (50 cm). And the test was conducted. The measurements in the case of the former simple sound barrier "L _b", "L _0" the measurement values in the case of mounting the latter soundproofing A2, the soundproofing A1, the measurement values in the case of mounting the same A3 “Lx (x = 1, 3)”.

Its soundproofing measurements _{L 0} The result of subtracting the former measurements _{L b} from the _{A2 (L 0 -L b (dB} )) to FIG. 5A, FIG. 5B. In this figure, the vertical axis is L ₀ -L _b (dB), and the horizontal axis is frequency (Hz). From this test result, the soundproofing device A2 has the latter soundproofing device as shown in FIGS. 5A and 5B. It was confirmed that the A2 soundproof wall was superior in sound reduction effect compared to the former simple soundproof wall, but in the specific frequency band such as 250 Hz, the latter was inferior to the former. That is, in a specific frequency band, it was confirmed that the sound reduction effect was lower than that of a simple soundproof wall (simple soundproof wall) B having the same height without the soundproof device A2.

On the other hand, the soundproofing A1, A3 is a noise reducing effect _{L 0} of soundproofing A2, soundproofing A1 (partition plate: ○), the A3 (polyester sound-absorbing material: ●) noise reducing effect _{L 1} or _{L 3} of The value subtracted from (Lx−L ₀ = ΔL (dB)) is shown in FIGS. 6A and 6B. Also in the figure, similarly, the vertical axis is Lx−L ₀ (dB), and the horizontal axis is frequency (Hz).
From this result, it can be confirmed that the soundproofing devices A1 and A3 have an effective sound reduction effect in the frequency band near 250 Hz as compared to the soundproofing device A2.

  Based on the above test results, it can be estimated that a similar sound reduction effect can be obtained in the soundproofing device A having the partition plate 17 and the sound absorbing material 18 at the required positions. In addition, when the partition plate 17 has an opening 17a like the reinforcing frame 17 '(thickening), noise passes through the opening 17a. Therefore, the position and shape (thickening) of the side plate 15 affects the sound reduction effect. It can be confirmed that, in the soundproofing device A, it is presumed that it is preferable that there is no reflection wall in the length direction.

Under the above knowledge, the inventor of the present application, after trial and error, does not provide the soundproofing device A in the above specific frequency band, and the reason why the sound reduction effect is lower than the simple soundproofing wall B of the same height is as follows. It was considered that a resonance phenomenon occurred in the space (room) formed by the side plates. The resonance phenomenon is considered to occur when the length between the side plates is an integral multiple of a half wavelength of the natural frequency in the length direction of the space.
Therefore, in the soundproofing device A1 of FIG. 1, the partition plate 17 is arranged so as not to be an integral multiple of a half wavelength of the frequency at which the resonance phenomenon occurs and the sound reduction effect is reduced. For example, in the soundproofing device A1, when the length of the space S (the length of the front wall plate 11) is about 2 m, a natural frequency of 250 Hz at which ≒ 67 cm, which is 1/3 of the length of the space, is a half wavelength. In this case, a resonance phenomenon occurs. Therefore, the partition plate 17 is provided at a position where the distance from the side plate 15 and the distance from each other are not about 67 cm.

Further, since the resonance phenomenon can be suppressed if the reflected sound itself is reduced, the sound absorbing material 18 is provided on the inner surface of the side plate 15 as in the soundproofing device A3 of FIG.
Further, since the resonance phenomenon due to the reflection of noise occurs due to the presence of the reflecting wall (surface), when the reinforcing frame 17 ′ having the opening 17 a is used for the partition plate 17, the side plate 15 is also the same as the reinforcing frame 17 ′. It is preferable to have a shape (open meat) having an opening 15a. I think.

  From the above, as a specific configuration of the present invention, there is a straight plate-like front and rear wall plate arranged in parallel in the vertical direction and a bottom plate that closes the lower surface between the front and rear wall plates, and multiplexing of incident sound between the front and rear wall plates. In a soundproofing device attached to the top of a road soundproofing wall so as to obtain a sound reduction effect by reflection, a configuration in which a sound absorbing material is provided on the inner surface of the side plate is adopted.

  In this configuration, the side plate may have an opening through which incident sound passes, and a sound absorbing material may be provided on the inner surface of the side plate other than the opening, and between the front and rear wall plates and the bottom plate of the space. A reinforcement frame having an opening can be provided, and a soundproof wall structure in which these soundproofing devices are connected in the length direction of the front wall plate can be employed. At this time, there can be no soundproofing device adjacent to the soundproofing device at both ends of the connected soundproofing wall structure, that is, the side plate of the soundproofing device located at the end most can be closed.

As another specific configuration of the present invention, vertical plate-like front and rear wall plates arranged in parallel in the vertical direction, a bottom plate that covers a lower surface between the front and rear wall plates, and a side surface of a space surrounded by the front and rear wall plates and the bottom plate are provided. A soundproofing device attached to the top of a soundproof wall for roads, wherein the soundproofing effect is obtained by multiple reflection of incident sound between the front and back wall plates, and is surrounded by the front and back wall plates and the bottom plate. A fully-closed partition plate that partitions the length direction of the front wall plate in the space, and the partition plate is configured not to be an integral multiple of a half wavelength of the frequency at which the sound reduction effect is reduced; and It can be set as the structure which provided the sound-absorbing material in the side plate inner surface, and the structure which employ | adopted both.
The frequency at which the sound reduction effect is reduced is appropriately determined by the experiment shown in FIG. 4 or the like for each required size and shape of the space.

In each of the above configurations, an intermediate plate can be provided between the front and rear wall plates. As long as the size of the intermediate plate is allowed, the number of intermediate plates may be one or two or any number.
The sound absorbing material may be a porous material, and in addition to polyester, aluminum fiber, glass wool, and the like are conceivable. The sound absorbing material can also be provided on the side surface of the partition plate. However, it is preferable to provide a sound absorbing material only on the side plate when a transparent material is used for the partition plate or the light is removed by removing the meat.
The front and rear wall plates or (and) the intermediate plate can be made of non-translucent metal such as iron plate, stainless steel, aluminum, etc., but if it is made of a translucent material (transparent material), the visibility is improved and soundproofing is achieved. It can reduce the apparent height of the wall and improve the sunshine problem. As the light-transmitting material, a resin such as acrylic or polycarbonate, a glass material, or the like can be used.

  Since the present invention is configured as described above, it is possible to obtain a soundproofing device with good soundproofing efficiency at low cost. Further, by appropriately setting the interval between the partition plates and the number of installed plates, it is possible to improve the reduction in the sound reduction effect in a specific frequency band and to effectively prevent sound.

1 shows an example of a soundproofing device according to the present invention, where (a) is a schematic perspective view, and (b) is a schematic cross-sectional view. Schematic perspective view of the other example Schematic perspective view of yet another example It is explanatory drawing of a soundproof test, (a) is a schematic front view, (b) is a schematic plan view. Relationship diagram between sound reduction effect (dB) and frequency (Hz) in soundproof test of one example of soundproofing device according to the present invention Relationship between sound reduction effect (dB) and frequency (Hz) Relationship between sound reduction effect (dB) and frequency (Hz) in a soundproof test of still another example of the soundproofing device Relationship between sound reduction effect (dB) and frequency (Hz) 1 shows an embodiment of a soundproofing device according to the present invention, where (a) is a schematic perspective view, and (b) is a schematic cross-sectional view. Installation state explanatory diagram of the same embodiment Schematic diagram of installation on the road

  Embodiments of the soundproofing device according to the present invention are shown in FIGS. 7 to 9, and the soundproofing device A4 of this embodiment is similar to the soundproofing devices A1 to A3 in the front wall plate (front plate) 11 arranged in parallel in the vertical direction. And a rear wall plate (back plate) 12, a bottom plate 13 that closes the lower surfaces of the front and rear wall plates 11 and 12, and a frame-like shape that forms the side surface of the space S surrounded by the front and rear wall plates 11 and 12 and the bottom plate 13 ( It is constructed on the top of a soundproof wall (soundproof wall) B made of concrete walls, soundproof plates, etc. on both sides of the elevated road, and has both sides of the soundproof wall B (the length of the road). It is provided in a state of being fitted on the upper portions of both support columns H on both sides (in the direction of the length) and sandwiched between them.

  Similarly, parallel intermediate plates 14 are provided between the front and rear wall plates 11 and 12 of the soundproofing device A4. The number of intermediate plates 14 is not limited to one, and may be two, three, or more. However, the interval between the plates 11, 14, 12 is appropriately determined according to the sound reduction target frequency between the plates 11, 14 and between the plates 14, 12. The lower part of the intermediate plate 14 is an inclined plate 19 that is inclined downward toward the front wall plate 11 and the tip thereof is close. The gap between the tip of the inclined plate 19 and the inner surface of the front wall plate 11 is made large enough to allow water (rain water) to pass through. The position and the inclination angle of the inclined plate 19 are tested according to the frequency Hz to be reduced by the space S so that multiple reflection in the space S between the intermediate plate 14 and the front wall plate 11 is performed. Set as appropriate.

The upper portion of the rear wall plate 12 is an upward inclined surface 12a toward the front wall plate 11, the lower end is continuous with the bottom plate 13, and the lower end portion of the intermediate plate 14 is inclined toward the front wall plate 11, There are gaps between the bottom plate 13 and the front wall plate 11.
The upper edge of each of the rear wall plate 12 and the intermediate plate 14 is bent inward to form a protruding piece 16. In the figure, 20 is an aluminum reinforcing frame fitted to the upper edge of the front wall plate 11, and 21 is a fitting material to the column H.
The front and rear wall plates 11 and 12, the bottom plate 13, the intermediate plate 14, the side plate 15, and the partition plate 17 are resin molded products made of a translucent resin material such as acrylic or polycarbonate.
A sound absorbing material 18 was affixed to the inner surface of the side plate 15 ′ where the support column H fits (other than the opening 15 a).

The soundproofing device A4 of this embodiment has the above-described configuration, and is constructed by replacing the soundproofing wall (soundproofing wall) B made of concrete walls or the like on both sides of the elevated road R, as shown in FIGS. It is provided in a state of being fitted on the upper portions of both pillars H on both sides (both sides in the length direction of the road) of the soundproof wall B.
In FIG. 9, each of the soundproofing devices A (A4) connected in the length direction of the road R has a mode in which there is no blocking wall over the entire length in the length direction. The (frame) 15 ′ may be a closed side plate 15.

In the soundproofing device A4 (soundproofing wall structure) of this embodiment, when the diffracted sound of the noise generated from the automobile traveling on the road R now reaches the soundproofing device A4, the diffracted sound is transmitted to each plate 11 as described above. , 12 and 14 enter the inside through the gaps at the upper ends, repeatedly collide (reflect) and interfere with the surfaces of the plates 11, 12 and 14, and gradually reduce energy by reducing energy.
In addition, the noise c that has entered (incident on) propagates in the longitudinal direction as well (see FIG. 4B), but because of the thinned side plate 15 ′ and the reinforcing frame 17 ′, the specific noise caused by reflection is reduced. Suppresses the resonance phenomenon in the frequency band. Further, the sound absorbing material 18 similarly suppresses reflection.
With the above sound reducing action, the soundproofing device A4 (soundproof wall structure) can effectively reduce road noise.

In order to prevent dust and the like from entering the opening at the top of each of the above soundproofing devices A (A1 to A4), install a net-like object, such as an expanded metal, covering the opening at the top. You can also. The opening rate of the expanded metal may be a level that does not reduce the sound reduction effect.
Although the said embodiment is a case where it provides in the soundproof wall of the elevated road R, it cannot be overemphasized that this invention can be employ | adopted for all the soundproof walls in the place which generate | occur | produces noise, such as a railway and a factory.
Thus, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

A, A1, A2, A3, A4 Soundproof device B Soundproof wall (soundproof wall)
c Noise 11 Front wall plate 12 of soundproofing device Rear wall plate 12a Inclined surface 13 Same bottom plate 14 Intermediate plate 15, 15 'Side plate 15a Side plate opening 16 Projection piece 17 Partition plate 17' Reinforcement frame 17a Reinforcement frame opening 18 Sound absorbing material 19 Inclined plate 20 Reinforcement frame 21 Fitting material

Claims (7)

Surrounded by straight plate-like front and rear wall plates (11, 12) arranged in parallel in the vertical direction, a bottom plate (13) closing the lower surface between the front and rear wall plates, and the front and rear wall plates (11, 12) and the bottom plate (13). A side plate ( 15 ′ ) that closes the side surface of the space (S), and is placed between the front and rear wall plates (11, 12) of incident sound that enters inside through a gap at the upper end of the front and rear wall plates (11, 12). that was to obtain a noise reducing effect by the multiple reflection, a soundproofing device mounted on top of the road noise barriers (B) (a),
Upper SL side plates (15 ') has an opening (15a) of the incident sound is passed through, the opening (15a) other than the side plates (15' provided sound-absorbing material (18) in) inner surface, said inner space (S) A soundproofing device characterized in that reflection of the incident sound propagating in the length direction of the front and rear wall plates (11, 12) is suppressed by the side plate (15 ') . Claim, characterized in that a reinforcing frame having an opening (17a) of the incident sound to pass through (17 ') between said front and rear wall panels of the space (S) (11, 12) and bottom plate (13) 1 soundproofing device according to. Surrounded by straight plate-like front and rear wall plates (11, 12) arranged in parallel in the vertical direction, a bottom plate (13) closing the lower surface between the front and rear wall plates, and the front and rear wall plates (11, 12) and the bottom plate (13). has a side plate (15) for closing the sides of the space (S), multi that put from the upper end of the gap the front and rear wall panels of the incident sound entering the interior (11, 12) between said front and rear wall panels (11, 12) A soundproofing device (A) that is attached to the top of a road noise barrier (B) that has a sound reduction effect by reflection,
A fully-closed partition plate (17) for partitioning the length direction of the front wall plate (11) in a space (S) surrounded by the front and rear wall plates (11, 12) and the bottom plate (13); and The partition plate (17) is arranged so as not to be an integral multiple of a half wavelength of the natural frequency in the length direction of the space (S), and between the side plate (15) and the partition plate (17) and the partition plate (17) A soundproofing device characterized by suppressing a resonance phenomenon of incident sound propagating in the length direction in a space formed between each other . The soundproofing device according to claim 3 , wherein a sound absorbing material (18) is provided on an inner surface of the side plate (15). The soundproofing device according to any one of claims 1 to 4 , wherein one or more intermediate plates (14) arranged in parallel are provided between the front and rear wall plates (11, 12). The front and rear wall panels (11, 12) or the soundproofing according to any one of claims 1 to 5, characterized in that the front and rear wall panel (11, 12) and intermediate plate (14) is made of a transparent plate apparatus. A soundproof wall structure, wherein the soundproofing device (A4) according to claim 1 or 2 is connected in a length direction of the front wall plate (11).

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