JPH052646Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a sound absorbing device suitable for reducing the noise of automobiles and the like traveling under elevated roads, elevated railways, etc.

(Prior art) Conventionally, as a sound absorbing device for the underside of an elevated road, a structure in which a fibrous sound absorbing material such as glass wool is attached to the back surface of the elevated road and held down with punched metal is common, but the fibrous sound absorbing material scatters If the fibrous sound absorbing material retains water due to water leakage from elevated structures or rainwater, the sound absorbing performance will deteriorate.Moreover, once water is retained, it is difficult to dry, so the recovery of the sound absorbing performance is extremely slow, and during that time There were many problems such as the metal parts being easily corroded, the work of attaching glass wool etc. to the underside of the viaduct was difficult to work with, and the fibers were likely to get stuck in the skin of the workers.

(Problems that the invention attempts to solve) This invention solves these conventional problems,
The sound-absorbing material does not scatter and can maintain a stable sound-absorbing effect over a long period of time.Also, the sound-absorbing material does not retain water and even if it retains water, it dries quickly and recovers the sound-absorbing effect quickly.It is also easy to manufacture and work. It was developed with the aim of creating a sound absorbing device that would not cause fibers to penetrate people's skin.

(Means for solving the problem) The present invention is a hollow columnar sound absorbing body made of a metal sound absorbing material and a sound insulating material in which a stack of metal fibers such as aluminum fibers is sandwiched between wire meshes in the shape of a sandwich. This structure is characterized in that a large number of columnar sound absorbers are mounted on the lower surface with a small distance between each other and a required space between them and the structure.

(Embodiment) Next, the present invention will be explained in more detail with reference to the illustrated embodiment. In FIG.
A large number of columnar sound absorbers are installed with a required space of about 3. As shown in the figure, each of these columnar sound absorbers 2 is formed of a metal sound absorbing material and a sound insulating material 6, in which a stack 4 of metal fibers such as aluminum fibers is sandwiched between wire meshes 5 in a sandwich shape.

This metal fiber stack 4 has a diameter of 25 to 100 μm,
It is made by pressure-molding metal fibers with excellent corrosion resistance such as aluminum fibers or stainless steel fibers with a fiber length of 10 mm or more to look like nonwoven fabric. Also, the wire mesh 5 sandwiching the outside like a sandwich has a mesh size of 1.
~5mm, wire diameter 0.3~1.0mm, thickness 0.4~1mm, aperture ratio
In this embodiment, an expanded metal with an opening of 2 mm, a wire diameter of 0.5 mm, a thickness of 0.5 mm, and an aperture ratio of 80% is used. The metal fiber stack 4 is sandwiched and crimped between the wire meshes 5 in a sandwich shape, or is then sintered as necessary to form a metal sound absorbing material with a thickness of 1 to 5 mm. However, simply crimping with a roller will lower the peel strength, so the
It is preferable to provide a strong pressure bonding portion with a small thickness at pitches. Such metal sound absorbing materials have low flow resistance.
It has excellent sound absorption properties of 500 to 1000 N·S/m ³ and also has excellent workability, mechanical strength, and corrosion resistance.

The columnar sound absorber 2 of the present invention is formed into a hollow shape from the metal sound absorbing material and the sound insulating material 6 as described above.
In this embodiment, as shown in FIG. 2, a columnar sound absorber 2 is formed by bending a metal sound absorbing material so as to have a rectangular cross section on the lower surface of a sound insulating board 6 such as a rope board or a plastic board.
is used, but its cross-sectional shape may be semicircular as shown in FIG. 3, or triangular as shown in FIG. In addition, sound insulation material 6
It may be bent into a U-shaped cross section and a metal sound absorbing material is attached to the lower surface. In either case, the depth from the sound insulating material 6 to the lowest part is about 150 to 300 mm, the width is about 300 to 500 mm, and the length can be any length in the longitudinal direction of the structure 1.
As shown in FIG. 1, such columnar sound absorbers 2 are attached to the lower surface of a structure 1 with a slight interval of about 5 to 100 mm between them. Note that the above numerical values indicate a preferable example, and the present invention is not limited to these numerical values.

(Function) In this structure, a large number of columnar sound absorbers 2 are attached to the lower surface of the structure 1, and a metal sound absorbing material and a sound insulating material 6 are sandwiched between metal fiber stacks 4 in a sandwich shape between wire meshes 5. Therefore, high-frequency noise emitted by automobiles and the like running on the road under the elevated bridge is effectively absorbed by the columnar sound absorbers 2. In addition, in a single unit of such columnar sound absorbing body 2,
Although it is not possible to obtain a high sound absorption coefficient in the low frequency region below 400 Hz, in the present invention, a large number of columnar sound absorbers 2 are provided with small intervals between them, and the required space 3 is left between them and the structure 1. Since I set it up and placed it,
Sound waves are transmitted from these intervals to the structure 1 and the columnar sound absorber 2.
Enter the space 3 between and this space 3
acts as a resonator, and low frequency parts are also sufficiently absorbed. When we actually measured the sound absorption performance of the sound absorbing device of the present invention shown in Figure 1, we found that as shown in Figure 5 with ●, the conventional sound absorbing device filled with glass wool (
Superior sound absorption properties were measured compared to those shown in the figure (marked). Moreover, in the present invention, the metal fiber stack 4 is replaced by a wire mesh 5.
Therefore, metal sound absorbing material sandwiched in a sandwich-like structure is used, and since this metal sound absorbing material has a thin wall thickness of about 1 to 5 mm, it has no water retention effect, and even if it absorbs water, it dries quickly. The sound deadening effect can be restored. That is, as shown by the x mark in Fig. 5, the sound absorption effect of the conventional product decreases significantly when submerged in water, and remains at a low level as shown in the figure even after 80 hours after submersion, but the sound absorption effect of the present invention As shown by the △ symbol, the sound absorption effect was almost completely recovered 5 hours after being immersed in water.

In addition, the sound absorbing device of the present invention does not scatter metal fibers, can maintain a stable sound damping effect over a long period of time, has a simple structure, and does not need to be filled with fibrous sound absorbing material like conventional methods. It is easy to manufacture because there are no fibers, and there are advantages such as there is no risk of the fibers getting stuck in the skin of the worker. Moreover, the structure in which a large number of columnar sound absorbers 2 are attached in the longitudinal direction of the structure 1 as in the embodiment has an excellent design effect and creates a psychological sense of oppression for drivers of cars driving on roads under elevated tracks. There are also benefits not to be given.

(Effects of the invention) As is clear from the above explanation, this invention can effectively absorb noise having a wide range of frequency components from high frequencies to low frequencies, and does not cause the scattering of fibers as in the conventional method. It is capable of maintaining a stable sound absorption effect over a long period of time, is difficult to absorb water, and even if water is absorbed, it dries in a short period of time and can quickly recover the sound absorption effect. In addition, the present invention has many advantages such as being easy to manufacture, not having to worry about rust, easy to install, and having excellent design effects. Therefore, the present invention has extremely great practical value as it eliminates the problems of conventional sound absorbing devices of this type.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention, FIGS. 2, 3, and 4 are perspective views showing columnar sound absorbers of various shapes, and FIG. 5 is a perspective view showing the sound absorbing device of the present invention. It is a sound absorption characteristic diagram of a conventional product. 1...Structure, 2...Columnar sound absorber, 3...Space, 4...Stack, 5...Wire mesh, 6...Sound insulating material.

Claims (1)

[Scope of utility model registration request] A hollow columnar sound absorber 2 made of a metal sound absorbing material and a sound insulating material 6 in which a stack 4 of metal fibers such as aluminum fibers is sandwiched between wire meshes 5 in a sandwich shape is attached to the lower surface of the structure 1. A sound absorbing device characterized in that a large number of sound absorbing devices are installed with a slight interval between them and a required space 3 between them and the structure 1.