JPS5852044B2 - soundproof wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in soundproof walls for absorbing and mitigating noise in traffic areas.

Conventionally, soundproof walls have been installed on the side edges of roads in order to absorb and alleviate the noise from vehicles traveling on expressways and other traffic areas, but as is well known, conventional soundproof walls are opaque walls. Because of this, there were problems such as not being able to see the scenery, giving the driver a feeling of oppression, and impairing the sense of speed.

In order to solve the above-mentioned problems, a soundproof wall having both a sound reduction effect and transparency has already been disclosed in Japanese Patent Application Laid-open No. 49-87127.

The technology disclosed herein uses a triangular prism that utilizes the principle of a Helmholtz resonator as a sound insulator, and attaches the triangular prism to the side edge of the road at a short distance with the apex facing the traffic area (road). By erecting a large number of them, the driver can see a continuous view of the outside of the soundproof wall without being obstructed by the triangular prisms due to the afterimage phenomenon.

The inventors of the present application have repeatedly conducted various research and experiments regarding the invention disclosed in the above-mentioned published patent, but as far as the invention disclosed in the published patent is concerned, five
It was found that it cannot absorb sound waves below 00 Hz (see Figure 5).

However, traffic noise is a mixture of sound waves with frequencies of about 125 Hz to 2000 Hz, and there is a practical problem if sound waves of 500 Hz or less cannot be absorbed.

Furthermore, it was found that the sound absorption coefficient obtained by the reverberation room method was still not sufficient (see Fig. 6), and there was room for various improvements.

Therefore, an object of the present invention is to improve the drawbacks of the above-mentioned published patent invention and to obtain a soundproof wall that can withstand practical use.

That is, in the present invention, a sound insulator 1 formed of a hollow triangular prism is erected so that one side thereof faces a traffic area, and a large number of sound absorption holes 2 are opened in the surface, and the inner cavity of the sound insulator 1 is The area is filled with sound absorbing material 3, and a large number of sound insulating bodies 1 are erected on the side edges of the traffic area at short intervals, similar to the disclosed patent invention.

The sound absorption holes 2 formed on one side of the sound insulation body 1 may be a large number of circular holes as shown in the figure, or may be vertical or horizontal slits, and in either case, the aperture ratio is 2 relative to the surface area.
Approximately 0 to 40 fb is preferable.

Further, examples of sound absorbing materials include glass wool, rock wool, and foam.

The above-mentioned sound insulating body 1 is usually connected at the top and bottom by other members, and is constructed in the form of a fence with pillars interposed at appropriate intervals, and is erected on the roadside edge.

As a specific example of the sound insulation body 1, one side is made of metal and has a width of 9.7 mm.
(There is one in which a 1 m regular triangular prism is formed, and the distance between the sound insulation bodies 1 (the distance between the road side surfaces) is 0.3 cm.

The sound insulation body 1 of the present invention constitutes a Helmholtz resonator as referred to in the disclosed patent invention, and when the incident sound waves reach the front surface of the sound insulation body 1, most of them enter the sound absorption holes 2, and other sound waves are It passes through the gap between the sound insulation bodies 1 (see Fig. 2).

When the sound waves reach the sound absorption holes 2, most of their energy is consumed to push the air inside the sound absorption holes 2 into the resonance chamber, and the sound waves entering the room are absorbed by the sound absorption material 3, such as glass wool, filled in the sound insulation body 1. It is absorbed and attenuated by the

Comparative data on the sound reduction effects of the present invention and a conventional general soundproof wall are shown in FIG.

In the same figure, numbers 4 and 5 are for the soundproof wall of the present invention (height 3m), number 4 is for the case where tape recording of the sound source of the Kagami Expressway is used, and number 5 is for the sound of a large vehicle running. It is.

6 and 7 are cases of soundproof walls conventionally used for noise prevention measures on expressways.

According to this, it can be seen that the sound reduction effect of the soundproof wall of the present invention is not inferior to that of the conventional wall.

FIG. 4 shows the measurement of the attenuation effect according to frequency for the soundproof wall of the present invention, and FIG. 5 shows the results of measuring the transmission loss of the soundproof wall of the present invention and the one of the disclosed patent invention.

The curve indicated by reference numeral 8 is that of the present invention, and the curve 9 is that of the disclosed patent invention.

FIG. 6 shows the results of measuring sound absorption coefficients by the reverberation chamber method for the present invention and the disclosed patent invention, where 10 indicates the present invention and 11 indicates the disclosed patent invention.

As is clear from FIG. 5, the disclosed patent invention does not have the ability to absorb sound waves of 500 Hz or less, but the one of the present invention has a sound absorbing effect even at lower frequencies.

Further, in FIG. 6, it can be seen that the sound absorption coefficient of the present invention is significantly good.

The present invention has a better sound reduction effect over a wider band than the disclosed patent invention.

In the sound insulation body of the published patent invention, the apex of the triangular prism faces the traffic area side and sound absorbing openings are provided on both sides, whereas in the sound insulation body 1 of the present invention, one side of the triangular prism faces the traffic area side and It is clear that the difference lies in the structure in that a large number of sound absorbing holes 2 are provided on the surface and the presence or absence of filling with sound absorbing material 3.

Even if the material of the disclosed patent invention is filled with a sound absorbing material similar to that of the present invention, it will not be possible to achieve a sound reduction effect equal to or greater than that of the present invention.

In conclusion, the present invention further enhances the effects of the disclosed patent invention by oriented the sound insulator 1 so that one side faces the traffic area and by providing a large number of sound absorption holes 2 on that side. It can be said that there is.

In the case of the soundproof wall of the present invention, the principle is that if the driver runs at a speed above a certain level, the scene outside the soundproof wall will be seen continuously without being blocked by the soundproof body 1 due to the afterimage phenomenon in the eyes. The content is similar to that disclosed in the published patent invention.

As described above, the present invention is similar to the disclosed patent invention in that the scene outside the soundproof wall is continuously visible to the driver, but the sound reduction effect is the same as that of the disclosed patent invention in a wide frequency band. It has been further improved, and its sound reduction effect is comparable to that of conventionally commonly used soundproof walls.

Therefore, if the soundproof wall of the present invention is used in place of the conventional soundproof wall without transparency, it is possible to eliminate various mental burdens on drivers.

It can exhibit remarkable effects such as good ventilation in traffic areas.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view, Fig. 2 is a plan view showing the propagation state of sound waves, Fig. 3 is a graph showing a comparison of the attenuation effect with a conventional soundproof wall, and Fig. 4 is a soundproof wall of the present invention. Graph showing the attenuation effect by frequency, Figure 5 is a graph showing transmission loss,
FIG. 6 is a graph showing the measurement results of sound absorption coefficient by the reverberation room method. 1...Sound insulation body, 2...Sound absorption hole, 3...
...Sound absorbing material.

Claims (1)

[Claims] 1. A large number of sound insulation bodies made of hollow triangular prisms are erected at regular intervals along a traffic area, and when the scenery behind the sound insulation bodies is seen through the gaps from a vehicle traveling in the traffic area at a speed above a certain level, In a soundproof wall, the gap between the sound insulation bodies is determined to such an extent that the scenery can be seen as a continuous scene without being obstructed by the sound insulation body due to the afterimage phenomenon of the eye, and the sound insulation effect is not impaired,
A large number of sound absorption holes are formed on one side of the sound insulation body, the remaining two sides are closed, the surface on which the sound absorption holes are provided faces the traffic area, and the inner cavity of the sound insulation body is filled with a sound absorption material. A soundproof wall characterized by: