JPS5845383B2 - Sound absorption wall for vehicles - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in sound absorbing walls for vehicles.

In recent years, the tendency for noise generated from vehicles to be highlighted as a pollution problem is increasing.

In addition, the noise generated when a vehicle is running is a factor in improving comfort by making the inside of a vehicle quieter, and it has become essential to install sound-absorbing walls in vehicles to reduce noise.

An example of a conventional sound absorbing wall will be described with reference to FIGS. 1 and 2.

In a mole rail car 3 that runs at high speed on a running girder 1 with tires 2, sound absorbing plates are attached to the skirt 4 and the lower part of the mole rail car frame in order to reduce noise from the traveling device.

The sound absorbing board 5 is made by covering short fiber sound absorbing material 7 with a waterproof plastic sheet 6, covered with a perforated board 8, and fixed to the inside of the skirt 4 with bolts 9.

Conventional general sound-absorbing walls are made by laminating and molding short fiber sound-absorbing materials such as rock wool, steel wool, glass fiber, hollow plastic fibers, etc., as described above. The material is covered with a plastic sheet made of polyethylene, polypropylene, polyvinyl chloride, etc., and the surface is protected with a perforated plate or the like.

In these cases, (the plastic sheet used to prevent the water absorption of class 1 sound materials must be made extremely thin to prevent the sound transmission rate from decreasing, but if this is done, water will penetrate and the sound absorption rate will decrease. happens.

(There are two places on the inside of the skirt, etc., where splashed water due to tire rotation becomes pressurized water, but this pressure water is not taken into account and the third
As shown in the figure, the time until dehydration is extremely long.

(As the plastic sheet ages, rainwater gets in and the sound absorption rate decreases.

There is a problem.

In reality, as shown in Figure 4, water accumulates on the surface of the internal sound absorbing material 7, which swells and becomes thicker in the center, or becomes corrugated, causing dimensional changes in the sound absorbing material and reduction in sound absorption coefficient due to vibrations from vehicles, etc. It has occurred.

In view of the above problems, the present invention aims to prevent water absorption, improve sound absorption coefficient, and maintain and improve sound absorption power.

The present invention provides a sound-absorbing panel board in which a perforated board is bonded with a breathable sound-absorbing material having a dense long fiber interval, and is provided with reinforcement;
A sound-absorbing material made of short fiber sound-absorbing material covered with glass cloth is installed together with the sound-absorbing material, which facilitates the drainage of water that seeps into the room due to pressure water.
It is possible to improve the sound absorption coefficient and further reduce specific frequency noise.

An embodiment of the present invention will be described with reference to FIGS. 6 to 8.

The frame 10 is made of a perforated plate 11 with an aperture ratio of 30 or more with a dense fiber spacing and a water-repellent treatment with a breathable thickness of 3 to 3.
A sound absorbing panel board 13 to which a 4 mm sound absorbing material 12 is glued is fitted and fixed with bolts or the like.

A sound absorbing material 15, which is a short fiber sound absorbing material 7 covered with a water-repellent glass cloth 14, is placed on the back side of the sound absorbing panel board 13, and is enclosed in a frame 10 with a cover 16.

A reinforcing material 17 is attached to the sound absorbing panel board 13 in a V shape.

Therefore, the noise that enters through the perforated plate 11- is absorbed by the sound-absorbing material 12, which has good air permeability and is water-repellent treated, and the other sound-absorbing material 1.
5 and the sound is attenuated as shown in Figure 5.

In this case, the specific frequency can be changed depending on the aperture ratio of the perforated plate 11.

Next, the pressure water scattered by the tire rotation is first received by the sound-absorbing panel board 13, but since this has air permeability to enhance the characteristics of the perforated sound-absorbing material, it can be used for a short period of time as shown in Figure 3. is dehydrated.

Further, the permeated water becomes a situation where water droplets are scattered on the surface of the sound absorbing material 15 due to the air permeability of the sound absorbing panel board 130.

The reinforcing material 17 that also serves as the rigidity of the sound absorbing panel board 13 is the sound absorbing material 1
Since the surface of the sound absorbing material 150 is pressed to have an undulating shape to facilitate drainage, that is, the surface of the sound absorbing material 150 has a groove 18 shape on the water receiving surface as shown in FIG. 8, so that the drainage effect is great.

Water passes between the sound absorbing material 15 and the reinforcing material 17 and is discharged from the drainage hole 19.

Particularly when used as a vertical wall, if the thickness is varied in the vertical direction, i.e., t>t2, even if the sound absorbing material 15 absorbs water and swells, it will not easily fall downward, and deviations due to vehicle vibration will be reduced.

Further, the reinforcing material 17 prevents the sound absorbing material 15 from slipping down due to vehicle vibration.

As another example, as shown in FIG. 9, if the thickness of the sound absorbing material 15 is kept constant and the upper and lower thicknesses of the frame 10 are varied as T1>T2 to form an air layer, the sound absorbing material and the air layer will absorb sound. In addition to improving the effect, since the sound absorbing panel board 13 is inclined, drainage treatment is further improved.

The shape of the reinforcing material attached to the sound-absorbing panel board does not have to be V-shaped as shown in FIG. 7, but may also be shaped as shown in FIG. 10, and these may be selected depending on the structure of the sound-absorbing wall and the place of use.

Alternatively, the sound absorbing panel 13 itself may be partially molded to have a reinforcing structure, as shown in FIG. 11, without separately attaching a reinforcing material.

The sound absorbing material 15 does not have to be the same size as the frame 10, but the reinforcing material 1
It is also possible to use small units divided by 7, but in this case the sound absorption coefficient will be slightly lower than that shown in FIG.

As described above, the present invention is a perforated board with a reinforcement material provided on a sound absorbing material that has dense fiber spacing and also serves as air permeability, and a sound absorbing material made of a short fiber sound absorbing material covered with glass cloth. Therefore, the water content decreases, the sound absorption coefficient improves by combining sound absorbing materials, and specific frequencies can be simultaneously absorbed by changing the aperture ratio of the perforated plate.

In addition, the reinforcing material can prevent the internal sound absorbing material from shifting due to vibration, making it highly effective as a sound absorbing wall for areas where pressure water is generated or for vehicles with high wind speeds.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a mole rail car, Figure 2 is a cross-sectional view of a conventional sound-absorbing wall, Figure 3 is a line diagram showing the state of water absorption and desorption of old and new sound-absorbing materials, and Figure 4 is a water absorption diagram of a conventional sound-absorbing wall. FIG. 5 is a diagram showing the sound absorption coefficient; FIGS. 6 and 7 are a sectional view and front view of the sound absorption wall of the present invention; FIG. 8 is a drainage structure of the sound absorption wall of the present invention. FIG. 9 is a cross-sectional view of another embodiment of the present invention, FIG. 10 is a front view showing an example of installing a reinforcing material, and FIG. 11 is a cross-sectional view of an example in which a reinforcing material is provided on a sound-absorbing panel board. It is a diagram. 7... Short fiber sound absorbing material, 10... Frame, 1
1... Perforated board, 12... Sound absorbing material, 1
3...Sound absorbing panel board, 14...Glass cloth, 15...Sound absorbing material, 16...Cover, 17...Reinforcement material, 18...Groove.

Claims (1)

[Claims] 1. A sound-absorbing panel board in which a breathable sound-absorbing material with dense fiber spacing is adhered to a perforated board provided on the sound source side, and a sound-absorbing material in which a short fiber sound-absorbing material is covered with glass cloth. and is attached to the frame,
A reinforcing material is provided on the back surface of the sound-absorbing panel so that drainage grooves are formed on the water-receiving surface of the sound-absorbing material by installing the sound-absorbing panel and the sound-absorbing material together, and a drainage hole is provided at the bottom of the frame. Sound absorbing walls for vehicles. 2. The sound absorbing wall for a vehicle according to claim 1, wherein the thickness of the sound absorbing material is thicker in the upper part and thinner in the lower part.