JP3815935B2 - Reduction structure of traffic noise radiated upward - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure for reducing traffic noise on a road or railway having walls on both sides and an opening at the top.
[0002]
[Prior art]
In order to reduce traffic noise radiated upward on roads or railways having walls on both sides and openings on the upper side, the applicant assigns a plurality of sound-absorbing plates having a sound-absorbing surface facing downward to the openings in the horizontal direction. Invented a structure for reducing traffic noise that was installed, and applied for a patent earlier (Japanese Patent Application No. 10-11001). Among the specific examples disclosed in this application, a plurality of sound-absorbing plates 1 having a downward sound-absorbing surface that is horizontal in the opening are installed in two upper and lower stages spaced apart from each other in the horizontal direction. The structure in which the lower sound-absorbing plates are arranged in a staggered manner so that the gaps do not overlap in the vertical direction is particularly effective in reducing noise. Because sunlight is incident, natural light can be expected in terms of illumination.
[0003]
[Problems to be solved by the invention]
By the way, it is advantageous from the viewpoint of illumination that the sunlight enters from the gap between the sound absorbing plates as described above, but on the other hand, as shown in FIG. 15, the incident direct light (the path is indicated by a broken line). Since the light and dark portions of the hit part and the non-contact part appear alternately on the road surface, it may be difficult for a person driving an automobile or a railway vehicle to drive.
The present invention has been made in view of such a problem of the above-described traffic noise reduction structure, and maintains an excellent noise reduction effect, and can be directly applied to a road or a railway without impairing exhaust gas ventilation performance as much as possible. The incident light is completely prevented and the indirect light after being reflected at least once is actively taken in.
[0004]
[Means for Solving the Problems]
The present invention (Claim 1) relates to a structure for reducing traffic noise radiated upward in a road or railway having walls on both sides and having openings in the upper part, and a plurality of sound absorbing plates having a downward sound-absorbing surface horizontal in the openings. Installed in two levels, spaced apart from each other in the horizontal direction, and arranged in a staggered manner so that the upper and lower sound-absorbing plates do not overlap in the vertical direction, and the upper and / or lower sound-absorbing plates A light-shielding plate or a sound-absorbing plate is installed vertically in the gap to prevent direct light from entering completely .
Further, the present invention (Claim 2) is characterized in that a light shielding plate or a sound absorbing plate is vertically installed at the end of the upper or / and lower sound absorbing plate as means for preventing direct light incidence. (3) The present invention (Claim 4) is characterized in that a lattice-like plate is installed in the gap between the upper and / or lower sound-absorbing plates so that the lattice opening surface is the upper and lower surfaces of the plate. An acoustic lens is incorporated in a gap between the upper and / or lower sound absorbing plates.
The above four means can be combined as appropriate. Further, as shown in FIG. 15, the upper and lower sound absorbing plates are preferably installed in parallel to each other so that the longitudinal direction thereof is along the extending direction of the road or railway. However, it may be installed vertically or obliquely.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to FIGS.
Now, in the traffic noise reduction structure shown in FIG. 15, light can directly enter through the path shown by the wavy line. FIG. 16 is an enlarged view of the upper and lower sound absorbing plates 1 and 2 and the gaps 3 and 4 therebetween. If the same sound absorbing plate (width W, thickness t) and sound absorbing plate interval (width L) are used in the upper and lower stages, and the distance between the lower surface of the upper sound absorbing plate and the upper surface of the lower sound absorbing plate is H, the gap 3 The minimum angle directly incident through 4 is θ _min = tan ⁻¹ {(2H + 4t) / (W + 3L)}, and the maximum angle is θ _max = tan ⁻¹ {2H / (WL)}. That is, it is only necessary to prevent direct light from entering within the range of the angles θ _{min to} θ _max .
[0006]
The traffic noise reduction structure shown in FIG. 1 is a structure in which a light shielding plate 5 is vertically inserted in the center of the gap 3 of the upper sound absorbing plate 1 in addition to the structure of FIG. Prevents incidence. Originally, a flow of ventilation gas in the vertical direction is generated at the center of the gap 3, so that the ventilation performance is hardly impaired by the light shielding plate 5. As the light shielding plate 5, for example, if the surface is light-colored and the surface is rough, the reflected light can be sufficiently diffused and the indirect light can be taken into the road surface.
It is also possible to use a sound absorbing plate (preferably having both surfaces as sound absorbing surfaces) instead of the light shielding plate 5, in which case the noise reduction effect is increased. However, since the opening area is reduced by the thickness of the sound absorbing plate, the ventilation performance is lowered. Needless to say, the sound absorbing plate has a light shielding function.
[0007]
The traffic noise reduction structure shown in FIG. 2 is one in which a light shielding plate 5 is inserted vertically in the center of the gap 4 of the lower sound absorbing plate 2, and direct light incidence is prevented by this light shielding plate 5. The effect is the same as the structure shown in FIG. Further, a sound absorbing plate can be used in place of the light shielding plate 5.
In the structure of FIGS. 1 and 2, the light shielding plate 5 (or sound absorbing plate) is installed in either the upper gap 3 or the lower gap 4. However, as shown in FIG. The light shielding plate and the sound absorbing plate can be mixed.
[0008]
The traffic noise reduction structure shown in FIG. 4 is such that light shielding plates 5 are installed vertically at both ends of the upper sound absorbing plate 1, and direct light incidence is prevented by the light shielding plates 5. However, the sound absorbing plates 1a at both ends do not require and are not provided with a light shielding plate because of the direct light incident direction. The light shielding plate 5 does not hinder the flow when the ventilation gas is sucked in, but when the ventilation gas is discharged, it becomes a flow hindrance and the ventilation performance is slightly reduced. It is also possible to use a sound absorbing plate (preferably having both surfaces as sound absorbing surfaces) instead of the light shielding plate 5, in which case the noise reduction effect is increased.
[0009]
The traffic noise reduction structure shown in FIG. 5 is one in which light shielding plates 5 are installed vertically upward at both ends of the lower sound absorbing plate 2, and direct light incidence is prevented by the light shielding plates 5. The light shielding plate 5 does not hinder the flow when ventilation gas is discharged, but becomes a flow hindrance when the ventilation gas is sucked, and the ventilation performance is slightly reduced. In place of the light shielding plate 5, a sound absorbing plate (having the surface facing the gap 4 as a sound absorbing surface) can be used, and in that case, the noise reduction effect is increased.
[0010]
The traffic noise reduction structure shown in FIG. 6 is one in which the light shielding plates 5 are installed vertically upward at both ends of the upper sound absorbing plate 1 and the light shielding plates 5 prevent direct light incidence. However, a light-shielding plate is not necessary and installed on one side of the second sound-absorbing plate 1b from both ends because of the direct light incident direction. The light shielding plate 5 does not significantly affect the flow of the ventilation gas, so that the ventilation performance is hardly impaired, but the light shielding plate 5 needs to have enough strength to withstand strong winds such as typhoons. In place of the light shielding plate 5, a sound absorbing plate (a surface facing the gap 3 as a sound absorbing surface) can be used, and in that case, the noise reduction effect is increased.
[0011]
The traffic noise reduction structure shown in FIG. 7 is one in which light shielding plates 5 are installed vertically at both ends of the lower sound absorbing plate 2, and direct light incidence is prevented by the light shielding plates 5. However, since there is no gap on one side of the sound absorbing plates 2a at both ends, a light shielding plate is unnecessary and is not installed. The influence of the light shielding plate 5 on the ventilation performance depends on the wind speed in the roadway, and the ventilation performance decreases as the wind speed in the roadway increases. It is also possible to use a sound absorbing plate (preferably having both surfaces as sound absorbing surfaces) instead of the light shielding plate 5, in which case the noise reduction effect is increased.
[0012]
In addition, the traffic noise reduction structure shown in FIG. 8 is another example in which the light shielding plates 5 are attached to both ends of the upper sound absorbing plate 1. 4 to 8, the light shielding plate 5 (or the sound absorbing plate) is installed at either the both ends of the upper sound absorbing plate 1 or the lower sound absorbing plate, but may be installed on both the upper and lower sound absorbing plates. In some cases, a light shielding plate and a sound absorbing plate can be mixed.
Furthermore, for example, as shown in FIG. 9, it is possible to combine a structure in which the light shielding plate 5 is installed in the gap of the sound absorbing plate and a structure in which the light shielding plate 5 is installed at the end of the sound absorbing plate.
[0013]
The traffic noise reduction structure shown in FIG. 10 is a structure in which a honeycomb plate 6 (see FIG. 11) including a honeycomb core 6a is horizontally installed in a gap 3 of an upper sound absorbing plate 1, and has a hexagonal lattice shape. The opening surface of the core 6 a is the upper and lower surfaces of the honeycomb plate 6. Sunlight incident from an oblique direction is blocked by the wall surface of the core by the honeycomb plate 6 to prevent direct light from entering. Further, since the ventilation gas passes through the lattice-like core 6a with almost no resistance, the ventilation performance is not significantly impaired.
In FIG. 10, as a method of installing the honeycomb plate 6 in the gap 3 of the sound absorbing plate 1, the honeycomb plate 6 is placed in the gap 3 (two on the left), and the top of the gap 3 is placed on the sound absorbing plate 1. In the latter case, the frame 6b on both sides of the honeycomb plate does not block the gap 3 if the width of the core 6a is equal to or greater than the width of the gap 3. Therefore, the aperture ratio of the gap 3 does not decrease so much. It is also possible to close the bottom of the gap.
[0014]
The conditions of the lattice shape when the honeycomb plate 6 is used can be calculated as follows. As shown in FIG. 12, it is assumed that the sound absorbing plates 1 and 2 are both installed with the same sound absorbing plate (width W, thickness t) and the distance between the sound absorbing plates (width L). Assuming that the distance between the upper surfaces of the plates is H, and the honeycomb plate 6 is placed on the sound absorbing plate 1, the maximum angle at which light directly enters through the gaps 3 and 4 is θ _max = tan ⁻¹ {2H / (WL)}. On the other hand, if the maximum width of the lattice of the honeycomb plate 6 is W _cel and the lattice height is H _cel , the condition for preventing direct light transmission is tan ⁻¹ (H _cel / W _cel )> θ _max , and eventually , H _cel / W _cel > 2H / (WL).
[0015]
The traffic noise reduction structure shown in FIG. 13 is such that a honeycomb plate 6 is horizontally installed in the gap 4 of the lower sound absorbing plate 2, and the opening surface of the hexagonal lattice-like core is the honeycomb plate as in FIG. 6 are the upper and lower surfaces. The effect of this structure is the same as that of FIG.
[0016]
The traffic noise reduction structure shown in FIG. 14 incorporates an acoustic lens 7 in the gap 4 of the lower sound absorbing plate 2 and prevents direct light from entering while performing ventilation for ventilation by the acoustic lens 7. In the case of this structure, the acoustic lens 7 can provide a further soundproofing effect. For example, when the above honeycomb plate 6 is installed in the gap 4 of the lower sound absorbing plate 2 (see FIG. 13), the sound wave having a wavelength λ smaller than the lattice interval W _cel of the honeycomb plate 6 passes through the honeycomb plate 6 and is then directed. Therefore, the sound wave radiated directly from the gap 3 to the outside of the upper opening without being absorbed by the upper sound absorbing plate 1 is generated. However, when the acoustic lens 7 is installed in the gap 4 of the lower sound absorbing plate 2, the directivity of the sound wave passing therethrough is strengthened and positively applied to the sound absorbing surface of the upper sound absorbing plate 1, so The energy of sound passing through the upper opening can be reduced, and a further soundproofing effect can be obtained.
On the other hand, when an acoustic lens is installed in the upper gap 3, it is possible to emit sound waves with directivity only upward where there is no private house. And it can also be installed in both the upper and lower gaps 3 and 4, in which case the air permeability is reduced by that amount, but the effects of both installations in the lower gap 4 or the upper gap 3 are obtained. It is done.
The acoustic lens itself is a well-known technique.
[0017]
【The invention's effect】
According to the structure for reducing traffic noise according to the present invention, direct light is prevented from being incident on a road or a railway, and light and darkness of a portion where the incident direct light strikes and a portion where it does not strike appear alternately on the road surface and are difficult to drive. It can be prevented from becoming a state. In addition, the ventilation performance of the exhaust gas is hardly or not significantly impaired, and the excellent noise reduction effect is maintained. Furthermore, for example, if the surface of the light shielding plate is lightly painted and the surface is rough, the reflected light is sufficiently diffused, and the indirect light after being reflected once or more is actively taken in, Decrease in lighting on the road or railway can be prevented.
[Brief description of the drawings]
FIG. 1 shows an example of a traffic noise reduction structure according to the present invention in a cross section perpendicular to the longitudinal direction of a road or railway.
FIG. 2 is another example of the traffic noise reduction structure according to the present invention.
FIG. 3 is another example of the traffic noise reduction structure according to the present invention.
FIG. 4 is another example of the traffic noise reducing structure according to the present invention.
FIG. 5 is another example of the traffic noise reduction structure according to the present invention.
FIG. 6 is another example of the traffic noise reduction structure according to the present invention.
FIG. 7 is another example of a traffic noise reduction structure according to the present invention.
FIG. 8 is another example of the traffic noise reduction structure according to the present invention.
FIG. 9 is another example of the traffic noise reduction structure according to the present invention.
FIG. 10 is another example of the traffic noise reduction structure according to the present invention.
FIG. 11 is a perspective view of a honeycomb plate used for it.
FIG. 12 is a diagram for explaining conditions of the shape of a grating for preventing direct light.
FIG. 13 is another example of the traffic noise reduction structure according to the present invention.
FIG. 14 is another example of the traffic noise reduction structure according to the present invention.
FIG. 15 shows an example of a traffic noise reduction structure based on the present invention in a cross section perpendicular to the longitudinal direction of a moat split road.
FIG. 16 is an enlarged view of a part thereof and is a diagram for explaining an incident angle of direct light.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper sound absorbing plate 2 Lower sound absorbing plate 3 Gap between upper sound absorbing plates 4 Gap between lower sound absorbing plates 5 Light shielding plate 6 Honeycomb plate 7 Acoustic lens

Claims (4)

A structure for reducing traffic noise radiated upward in roads or railways with walls on both sides and openings in the upper part, and a plurality of sound-absorbing plates having a downward sound-absorbing surface horizontal in the openings are horizontally spaced from each other The upper and lower sound-absorbing plates are arranged in a staggered manner so that the gaps do not overlap each other in the vertical direction. reducing structure of traffic noise, characterized in that completely prevented the entry of direct light by installing the plate vertically. A structure for reducing traffic noise radiated upward in roads or railways with walls on both sides and openings in the upper part, and a plurality of sound-absorbing plates having a downward sound-absorbing surface horizontal in the openings are horizontally spaced from each other The upper and lower sound-absorbing plates are arranged in a staggered manner so that the gaps do not overlap each other in the vertical direction. reducing structure of traffic noise, characterized in that completely prevented the entry of direct light by installing the plate vertically. A structure for reducing traffic noise radiated upward in roads or railways with walls on both sides and openings in the upper part, and a plurality of sound-absorbing plates having a downward sound-absorbing surface horizontal in the openings are horizontally spaced from each other The upper and lower sound-absorbing plates are arranged in a staggered manner so that the gaps do not overlap each other in the vertical direction. A structure for reducing traffic noise, in which the grid opening surface is placed on the upper and lower surfaces of the plate to completely prevent direct light from entering. A structure for reducing traffic noise radiated upward in roads or railways with walls on both sides and openings in the upper part, and a plurality of sound-absorbing plates having a downward sound-absorbing surface horizontal in the openings are horizontally spaced from each other The upper and lower sound absorbing plates are arranged in a staggered manner so that the gaps do not overlap in the vertical direction, and an acoustic lens is installed in the gap between the upper and / or lower sound absorbing plates. A traffic noise reduction structure characterized by completely preventing direct light from entering.

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