JP2929904B2 - Noise barrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound-insulating wall, and more particularly to a sound-insulating wall that does not use a transparent plate and that provides a sufficient sound-reducing effect and allows a vehicle to see the outside scenery.

[0002]

2. Description of the Related Art Conventionally, as a transparent soundproof wall installed on roads and railway lines to prevent vehicle noise, FIG.
As shown in (1), a transparent plate 1 made of glass, acrylic, polycarbonate, or the like (hereinafter, referred to as prior art 1),
Alternatively, there is a slit type as shown in FIG. 13 (hereinafter referred to as Conventional Technique 2).

[0003]

However, the prior art 1 has the following problems. Since the exhaust gas and dust of the vehicle adhere to the transparent plate 1, the transparency gradually deteriorates. Transparency of synthetic resins such as polycarbonate gradually deteriorates with aging. It is necessary to perform maintenance for maintaining the transparency of the transparent plate 1, and at this time, the surface of the transparent plate 1 is easily damaged. Expensive.

The prior art 2 has the following problems. Unlike the prior art 1, there is no problem that the transparency gradually deteriorates due to aging, but there is not much sound reduction effect. If the slit interval is small, the scene outside the wall cannot be seen sufficiently from the vehicle.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a soundproof wall which does not cause deterioration in transparency, provides a sufficient sound reduction effect, and allows a vehicle to fully view the outside scenery.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a plurality of sound deadening boxes having at least a pair of see-through slits formed on a vehicle side wall surface and an opposite vehicle side wall surface facing the vehicle side wall surface are arranged in a line. It has the characteristic that it consists of what was done.

[0007]

In general, the soundproofing effect of a soundproof wall is a function of the sound frequency and the path difference. When a soundproof wall is formed by using a wall having a very large transmission loss, a noise reduction effect as shown by a solid line (Maekawa's equation) in FIG. 11 showing the relationship between diffraction attenuation and Fresnel number can be obtained. . In other words, no matter how large the transmission loss, there is a limit to the sound reduction effect because there is a diffracted sound from the upper end of the wall surface. That is, it can be said that transmission loss equal to or greater than diffraction attenuation is meaningless.

First, the sound reduction effect of the slit type sound insulation wall of the prior art 2 is obtained from above in the literature and evaluated by the Fresnel number, as shown in FIG. This is more than the sneak noise due to diffraction, compared to a wall without slits.
This is because the level of sound transmitted through the wall is higher.

Next, using the sound insulating wall of the present invention shown in FIG. 1, under the same conditions as in the slit type sound insulating wall of the prior art 2 (the sound source position, the sound receiving point position, and the wall height are the same). To maintain), predicted the sound reduction effect. The soundproof wall of the present invention will be described later. The result is shown in FIG. At this time, transmission loss data shown in FIG. 4 was used. Although the transmission loss of the soundproof wall of the present invention is not as large as that of the soundproof wall without slits, it is larger than the diffraction attenuation value, so that the same soundproof effect as that without the slit is obtained.

[0010] By the way, in the case of a road noise barrier, a problem generally arises when the height of the noise barrier is (h), and it is sufficient to consider a point having a distance of about h at the closest point. .
In addition, in the distant place, considering a considerable distance, the height direction must be considered at the same time. Therefore, as shown in FIG. 14, due to the geometric relationship between the sound source (S) and the sound receiving point (P), the path difference (δ) can be considered to be general in consideration of the range represented by the following equation (1). There is no lack.

[0011]

## EQU1 ## 0.1h <δ <0.8h = 0.2h <2δ <1.6h

From this, the Fresnel number (N = 2δ / λ, λ =
When the range of (wavelength) is defined, the following equation 2 is obtained.

[0013]

## EQU2 ## 0.2h / λ <N <1.6h / λ

The main frequency in the case of road traffic noise is 50
Since it is 0 Hz to 2 KHz, if h = 4 m, the Fresnel number is in the range shown in Table 1. In this case, the amount of diffraction attenuation estimated from Maekawa's equation is as shown in Table 1. On the other hand, the transmission loss of the soundproof wall of the present invention shown in FIG. 1 is as shown in Table 1 below, and is substantially equal to the amount of diffraction attenuation according to Maekawa's equation. When this relationship is illustrated, as shown in FIG. 11, a diffraction attenuation effect substantially the same as the effect of the wall without the slit is obtained, and the soundproofing effect of the soundproofing wall of the present invention is smaller than that of the soundproofing wall of the prior art 2. It turns out that it is large enough and is equivalent to a normal wall.

[0015]

[Table 1]

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a cross-sectional view showing one embodiment of the soundproof wall of the present invention, FIG. 2 is a perspective view showing one embodiment of the soundproof wall of the present invention, and FIG. FIG. 4 is a perspective view showing a muffling box to be used.

As shown in FIG. 1 to FIG. 3, the soundproof wall of the present invention is formed by arranging sound absorbing boxes 2 in a rectangular parallelepiped shape with their short sides joined to each other. At least one pair (in this example, one pair) of see-through slits 3A, 3B is obliquely formed on the long side wall surface on the vehicle side of the muffling box 2 and the long side wall surface opposite to the vehicle side surface facing the vehicle side wall surface. Are formed opposite to each other. An example of the dimensions of the sound deadening box 2 is a height of 500 mm, a width of 500 mm, and a thickness of 150.
mm. Examples of the dimensions of the slit include a vehicle-side slit 3A having a width of 10 mm and a length of 250 mm, and a non-vehicle-side slit 3B having a width of 20 mm and a length of 270 mm. As shown in FIG. 2, the sound-absorbing box configured as described above is constructed of a plurality of bricks to form a soundproof wall.

According to the muffling box 2, the sound generated from the vehicle enters the muffling box 2 through the slit 3A, and thereafter, the energy of the sound is diffused by the sudden expansion of the cross section. As a result, a sound reduction effect appears in the slit 3B.

In the silencing box 2, a slit 3A,
FIG. 4 shows the sound reduction effect when a sound absorbing material is inserted so as not to affect the fluoroscopy by 3B. As a result, about 10
It was found that a sound reduction effect of dB or more was obtained. This value is not only sufficiently large as compared with the case of the above-described conventional sound-insulating wall of the slit type, but also comparable to that of the sound-insulating wall without slits. Moreover, the outside of the wall can be fully seen through the slits 3A and 3B from the vehicle. This means that the afterimage time of the human eye is about 0.3.
This is because the image can be viewed as a continuous image if slits are formed at a pitch of 300 to 500 mm even at a low speed of about 40 km / h, since the time is 03 to 0.05 seconds.

FIG. 5 is a sectional view showing a soundproof wall according to another embodiment of the present invention. This soundproof wall is formed by arranging sound absorbing boxes 4 in a rectangular parallelepiped shape with their short sides joined to each other in a line, and slits 5A and 5B for see-through are obliquely formed on the long sides. This is similar to the above-described embodiment, except that a slit 5C is also formed on the short side surface. As a result, it is possible to see through not only the slits 5A and 5B but also the slits 5A, 5C and 5B without reducing the sound reduction effect, so that a further see-through effect can be obtained. In this case, each slit 5
If the partition plate 6 is attached to C, a noise reduction effect can be obtained even in the process of passing from the slit 5A to the slit 5C. The sound reduction effect of the soundproof wall of FIG. 5 is also shown in FIG. As is clear from FIG. 4, it is clear that even if the slit 5C is formed on the short side surface, there is no particular disadvantage in terms of the sound reduction effect.

For example, when the dimensions of the soundproof wall in FIG. 5 are the same as those in FIG. 1, if the vehicle travels while maintaining a distance of about 3 m or more from the wall as shown in FIG. The direction outside of the wall can be seen simultaneously from eight or more slits at a distance of about 8 degrees to the left and 20 m ahead from the direction. Since the afterimage effect is added to this, a much wider field of view can be ensured as compared with the slit type soundproof wall of the related art 2.

FIG. 7 is a sectional view showing still another embodiment of the present invention. The sound deadening box 7 of the soundproof wall has a rectangular parallelepiped shape, and the slits 8A and 8B are formed on the short side surfaces. The soundproof wall is formed by joining the corners of the sound deadening box 7 to each other so as to be arranged in a line.

According to the soundproof wall of FIG. 7, the slits 8A, 8A
Since B is oriented in the viewing direction, a higher see-through effect can be obtained if the opening width of the slit is the same as in the soundproof wall of the embodiment shown in FIGS.

FIG. 8 is a sectional view showing still another embodiment of the present invention. The sound deadening box 9 of the soundproof wall is formed by joining two rectangular sound deadening box units 9A and 9B with their long sides joined to each other in parallel. The see-through slits 10A to 10E are formed on the short side surfaces of the sound absorbing box unit 9A and the long side surfaces joined to each other. The soundproof wall is configured by joining one of the short sides of the sound deadening box units 9A and 9B to each other and arranging them in a line.

According to the soundproof wall of FIG. 8, since the sound deadening box 9 is composed of two sound deadening box units 9A and 9B, a greater sound reduction effect can be obtained.

FIG. 9 is a sectional view showing still another embodiment of the present invention. The sound deadening box 11 of the soundproof wall is formed by joining two rectangular sound deadening box units 11A and 11B with their long sides joined together. The see-through slits 12A to 12D are formed on the short side surfaces of the sound deadening box units 11A and 11B, and are arranged in a line by joining one of the short side surfaces of the sound deadening box units 11A and 11B to each other. The formed slit 12C is configured by a slit plate 13 attached thereto.

According to the soundproof wall of FIG. 9, by attaching the slit plate 13 to the slit 12C formed on the short side surface, another noise reduction characteristic is further added, so that the frequency range in which the noise reduction effect appears is further expanded. .

FIG. 10 is a sectional view showing still another embodiment of the present invention. The sound deadening box 14 of the soundproof wall is composed of two rectangular sound deadening box units 14A and 14B joined in parallel with their long sides joined to each other. The see-through slits 15A to 15D are formed on the short sides of the sound deadening box unit, and are arranged in a line by joining one of the short sides of the sound deadening box units 14A and 14B to each other. Between the slits 15C and 15D, a perforated plate 1
6 is attached.

According to the soundproof wall of FIG. 10, the perforated plate 16 is provided between the slits 15C and 15D of one of the sound deadening box units 14B, so that a higher sound reduction can be achieved due to the interaction between the cavity volume and the hole area of the sound deadening box. The effect is obtained.

The slit formed in the soundproof wall of the above embodiment is advantageous in terms of the see-through effect if the width is increased as the distance from the vehicle is increased. Also, if a sound absorbing material is inserted so as not to affect the see-through through the slit, it goes without saying that the sound reducing effect is further increased.

[0032]

As described above, according to the present invention, the following effects can be obtained. Compared to Conventional Technique 1, there is no decrease in transparency due to aging. There is no need for maintenance due to the decrease in transparency. Since the slit has ventilation, the wind load can be reduced. Compared to the prior art 2, since it has a silencer structure, the sound reduction effect is large. Therefore, the slit width can be increased,
Great see-through effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a soundproof wall of the present invention.

FIG. 2 is a perspective view of a soundproof wall according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a sound deadening box constituting the soundproof wall of the present invention.

FIG. 4 is a graph showing the relationship between transmission loss and frequency for the soundproof wall of the present invention shown in FIGS. 1 and 5;

FIG. 5 is a sectional view showing another embodiment of the soundproof wall of the present invention.

FIG. 6 is a plan view showing a visual field effect in the soundproof wall of FIG. 5;

FIG. 7 is a sectional view showing still another embodiment of the soundproof wall of the present invention.

FIG. 8 is a sectional view showing still another embodiment of the soundproof wall of the present invention.

FIG. 9 is a sectional view showing still another embodiment of the soundproof wall of the present invention.

FIG. 10 is a sectional view showing still another embodiment of the soundproof wall of the present invention.

11 is a graph showing the relationship between the diffraction attenuation and the Fresnel number for the Maekawa equation, the prior art 2 and the soundproof wall of FIG. 1.

FIG. 12 is a cross-sectional view showing a conventional technique 1.

FIG. 13 is a cross-sectional view showing a conventional technique 2.

FIG. 14 is an explanatory diagram illustrating a geometric relationship between a sound source S and a sound receiving point P.

[Explanation of symbols]

 1: transparent plate, 2: sound deadening box of Example 1, 3A, 3B: slit, 4: sound deadening box of Example 2, 5A, 5B: slit, 6: partition plate, 7: sound deadening box of Example 3, 8A , 8B: slit, 9: sound deadening box of Example 4, 9A, 9B: sound deadening box unit, 10A to 10E: slit, 11: sound deadening box of Example 5, 12A, 12D: slit, 13: slit plate, 14: The sound deadening box of Example 6, 14A, 14B: sound deadening box unit, 15A to 15D: slit, 16: perforated plate.

Claims (8)

(57) [Claims] 1. A vehicle side wall surface and a front side of a hollow sound deadening box.
At least one pair is formed on the anti-vehicle side wall surface facing the vehicle side wall surface.
Are formed facing each other, and the silencing box
Are arranged in line with one another, thus
Enter the silencer box through the slits on both sides
The emitted sound, due to the rapid expansion of the cross section of the muffling box,
Being diffused and silenced in the silence box
A soundproof wall characterized by: 2. The muffling box is formed in a rectangular parallelepiped shape, and the slit is provided with a human after-image time and a vehicle speed.
Position obliquely opposite each other on the long side
The soundproof wall according to claim 1 , wherein the short side surfaces are joined to each other. 3. The sound deadening box is formed in a rectangular parallelepiped shape, and the slit is formed on a long side surface and a short side surface,
Characterized in that the short sides are joined to each other,
The soundproof wall according to claim 1. 4. The sound deadening box is formed in a rectangular parallelepiped shape, the slit is formed on a short side surface, and the sound deadening boxes are arranged in a line by joining their corners to each other. The soundproof wall according to claim 1, wherein 5. The sound deadening box comprises a rectangular parallelepiped sound deadening box unit in which two long side surfaces are bonded to each other and bonded in parallel, and the slit is formed on a short side of the sound deadening box unit. The soundproof wall according to claim 1, wherein the soundproof wall is formed on a surface and a long side surface joined to each other, and arranged in a line by joining one short side surface of the sound deadening box units to each other. 6. The silencing box comprises a rectangular parallelepiped silencing box unit in which two long sides are joined to each other and joined in parallel, and the slit is a short side of the silencing box unit. Are formed in a plane, and are arranged in a line by joining one of the short sides of the sound deadening box unit to each other, and a slit formed in the short sides joined to each other is provided with a slit plate. The soundproofing wall according to claim 1, wherein the soundproofing wall is characterized by: 7. The sound deadening box comprises a rectangular parallelepiped sound deadening box unit in which two long sides are bonded to each other, and two long sides are connected in parallel, and the slit is a short side of the sound deadening box unit. The soundproof wall according to claim 1, wherein a perforated plate is formed between the slits of one of the sound deadening box units. The method according to claim 8 in the muffling box, characterized in that the soundproofing material so as not to affect the perspective through the slit is inserted into any one of claims 1 to 7 The described soundproof wall.