JP4516932B2 - Translucent membrane vibration sound absorbing plate and translucent sound absorbing panel - Google Patents

Description

  The present invention belongs to the technical field related to soundproof walls such as roads and railways. More specifically, the present invention relates to a soundproof wall having not only a sound absorbing property but also a watermark and translucency through a sound absorbing panel as required.

  As a soundproof wall for roads and railways, the sound source side is a metal plate with many slits, and the back sound insulation plate is a metal plate in a metal housing, soft fiber porous sound absorption such as glass wool A material in which a material protected by a weather-resistant film is inserted for the purpose of preventing deterioration due to ultraviolet rays or rainwater is generally used.

  Another example is a translucent soundproofing wall that uses only transparent resin sound insulation plates as a countermeasure against sunlight and landscape on private houses on both sides of the road.

A soundproof wall filled with a soft fiber-based porous sound absorbing material such as glass wool, which is a general soundproof wall for roads and railways, has excellent noise reduction effect, but it has a problem of sunshine to private houses on both sides of the road. In addition to causing the above problem, the field of view outside the road is shielded, so that the passenger cannot see the outside scenery, causing a problem of a strong blockage.
Japanese Patent No. 2847066

In addition, the translucent soundproof wall using only the above-mentioned transparent resin sound insulation board is only a sound insulation effect even though it has excellent sunshine problem, visibility and landscape characteristics to private houses. The noise reduction effect on the sound source side cannot be expected. Accordingly, the sound pressure level on the sound source side remains high or higher, and as a result, the noise reduction effect on the private house is not sufficient.
Japanese Patent No. 3364338

More recently, although a light-transmitting / sound-absorbing soundproof wall that combines a light-transmitting membrane vibration sound-absorbing plate invented by the present inventors and a transparent resin sound-insulating plate has begun, the light-transmitting property is There are inherent problems such as not necessarily sufficient.
Japanese Patent No. 1922416

  An object of the present invention is to provide a light-transmitting membrane vibration sound-absorbing plate that solves the above-described problems and has more excellent sound-absorbing characteristics, light-transmitting properties, and watermarking properties.

  The inventors of the present invention have found a translucent membrane vibration sound absorbing plate having excellent sound absorption characteristics and translucency through many years of manufacturing experience and experimental verification of the translucent membrane vibration sound absorbing plate, and have reached the present invention. .

  According to a first aspect of the present invention, there is provided a translucent film vibration absorbing board characterized in that a transparent resin thin film is sandwiched between two plates having a large number of openings. One is an aluminum expanded metal that has been flattened in advance, and the flattening rate is in the range of 0.45% to 0.60%, and the other is a hole diameter of 5mm to 15mm, with a plate thickness of A translucent membrane vibration sound absorbing plate, characterized in that it is a transparent perforated resin plate having a range of 1 mm to 3 mm and an aperture ratio of 20% to 50%.

According to a second aspect of the present invention, the translucent membrane vibration sound absorbing plate according to the first aspect is provided with a transparent resin sound insulating plate on the sound source side and on the side opposite to the sound source, and these are used as frame members. It is a translucent sound-absorbing panel characterized in that an air layer is formed by holding in step (a).

  By using the translucent membrane vibration sound-absorbing plate of the present invention, it is possible to produce a soundproof wall for roads and railways, which is more excellent in translucency, watermarking and sound-absorbing characteristics.

  The translucent membrane vibration absorbing plate of the present invention will be described in detail with reference to the accompanying drawings.

  In the following description, the light-transmitting membrane vibration sound absorbing plate is a sound absorbing plate that can transmit sunlight and can see the outside scenery through the sound absorbing plate.

  Further, in the following description, expanded metal is a net-like metal plate in which a metal plate is cut using a special blade shape and at the same time, a mesh is formed while stretching it. FIG. 1 is a front view of one mesh 1 of expanded metal, FIG. 2 is a cross-sectional view taken along the line aa in FIG. 1, and FIG. 3 is a state in which the surface is flattened by roll rolling in the state of FIG. It is explanatory drawing.

  As is clear from FIG. 2, the expanded metal has a large undulation (unevenness) in the cross section, and therefore, when the fluorine-based transparent resin thin film 2 is sandwiched (the other plate-like body is omitted), the fluorine-based transparent resin. Insufficient contact with the thin film 2 results in insufficient sound absorption characteristics.

  FIG. 3 is an explanatory view showing a state in which the expanded metal is flattened using a rolling roll, and when the fluorine-based transparent resin thin film 2 is sandwiched (the other plate-like body is omitted), Since the contact with the fluorine-based transparent resin thin film 2 is sufficient, the sound absorption characteristics are also improved.

However, there is a relationship between the flattening rate and the sound absorption characteristics of the expanded metal, and the flattening rate can be obtained from the relationship between T shown in FIG. 2 and t shown in FIG.
R = (T−t) / T (Formula 1)
R: flattening rate
T: Original thickness of expanded metal (mm)
t: Thickness after flattening of expanded metal (mm)

  From the detailed examination results of the inventors, the flattening rate obtained by (Equation 1) is in the range of 0.45 to 0.60 in terms of sound absorption characteristics, and is in the range of 0.55 to 0.60. Is more preferred. The thickness of the expanded metal was measured using a thickness gauge 7305 manufactured by Deck Jam Co., Ltd .: a thickness gauge that displays the thickness on the dial gauge by holding the lever and sandwiching the measuring element (expanded metal).

  The thickness of the expanded metal after the flattening process is not particularly limited, and may be appropriately selected according to the required mechanical strength, the size of the translucent membrane vibration absorbing board, etc. In consideration of workability, weight, etc., the thickness is usually about 0.2 mm to 2 mm, preferably 0.4 mm to 1 mm.

  In the following description, the transparent perforated resin plate is a plate-like body obtained by punching a transparent resin plate, and there is no unevenness as in the case of the expanded metal, so no processing for flattening is required. It is.

The thickness of the transparent perforated resin plate in the present invention is practically in the range of 1 mm to 3 mm, but more preferably in the range of 1.5 mm to 2.0 mm.

  The opening shape of the transparent perforated resin plate is generally a circular staggered arrangement, but is not particular to this shape, and may be a rectangle, a rectangle, or a triangle.

When the opening shape is circular, the hole diameter is practically 5 mm to 15 mm, but more preferably 8 mm to 12 mm.

Moreover, the range of 20% to 50% is practical, but the range of 30% to 40% is more preferable.

Now, the sound absorbing mechanism of the translucent membrane vibration sound absorbing plate of the present invention will be described with reference to FIG.

 That is, when the sound wave S is incident on the surface of the translucent membrane vibration absorbing plate 3 from the sound source G, the fluorine-based transparent resin thin film 5 is vibrated by the action of the sound wave S (vibrating air). That is, sound energy is converted into vibration of the transparent resin thin film 5 and a sound absorbing action is exhibited. (Hereinafter referred to as sound absorbing action a. Not shown in the figure.)

Further, when the fluorine-based transparent resin thin film 5 vibrates as in the sound absorbing action a, friction is generated on the surface of the thin film and the surfaces of the expanded metal 4 and the transparent perforated resin plate 6 subjected to the flattening process in contact with the thin film. Sound energy is converted into heat energy, and as a result, sound energy is absorbed and absorbed. (Hereinafter referred to as sound absorbing action b. Not shown in the figure.)

The reason why the sound absorption characteristics are improved by flattening the expanded metal is presumed that the contact area between the fluorine-based transparent resin thin film 5 and the expanded metal is increased by the flattening, and the sound absorbing action b is increased.

Further, when the sound wave (S) collides with the translucent membrane vibration absorbing plate 3 and the plate is temporarily twisted or bent, the plate vibrates in an attempt to return according to the elasticity inherent in the plate. At this time, it is assumed that sound energy is converted to vibration energy and absorbed. (Hereinafter referred to as sound absorbing action c. Not shown in the figure.)

Now, as shown in FIG. 4, when the transparent resin sound insulating plate 7 is disposed behind the translucent membrane vibration sound absorbing plate 3 via the back air layer A, the sound absorbing characteristics of the translucent membrane vibration sound absorbing plate 3 are further improved. improves.

The reason for this is presumed that the vibration of the translucent membrane vibration-absorbing plate 3 compresses the back air layer A to generate a back pressure BP and exhibits a sound-absorbing action (hereinafter referred to as a sound-absorbing action d). Is not listed in.)

The translucent membrane vibration sound-absorbing plate 3 of the present invention exhibits excellent sound-absorbing characteristics due to the synergistic effect of the sound-absorbing actions a to c and further the sound-absorbing action d.

Further, by changing the size of the back air layer A, the peak of the sound absorption coefficient shown in FIGS. 7 and 12 can be moved.

That is, when the rear air layer A is increased, this peak moves to the left in the figure, so that the sound absorption characteristics on the low frequency side are improved. On the contrary, if the back air layer A is selected to be small, the peak moves to the right in the figure, so that the sound absorption characteristic on the high frequency side is advantageous.

  An aluminum expanded metal having a mesh size of 5 mm × 10 mm was flattened using a rolling roll and cut into a disk shape with a target of 99 mm in diameter.

  In addition, a transparent perforated resin plate 6 having a thickness of 1.5 mm, an opening diameter of 10 mm, an opening center distance (pitch) of 16 mm, an opening angle of 60 degrees, and an aperture ratio of 35% is formed with a diameter of 99 mm. The target was cut into a disk shape.

  A fluorine-based transparent resin thin film 5 having a thickness of 12 μm is prepared as a transparent resin thin film, and this is sandwiched between the flat aluminum expanded metal 4 and the transparent perforated resin plate 6 to measure the normal incident sound absorption coefficient. A translucent membrane vibration absorbing plate sample 8 was prepared.

  FIG. 5 shows a cross-sectional view of the translucent film vibration absorbing plate sample 8 for measuring the normal incident sound absorption coefficient of Example 1 described above. The aluminum expanded metal 4 having a mesh size of 5 mm × 10 mm and flattened was assembled on the sound source side, and the transparent perforated resin plate 6 was on the back air layer side.

  The figure is a conceptual diagram for explanation, and the size and the like of the expanded metal are not based on the actual size.

  The result of the measurement of the normal incident sound absorption coefficient based on JIS1405-1998 with the transparent film vibration absorbing plate sample 8 for measuring the normal incident sound absorption coefficient secured 100 mm behind the air layer is shown in the curve a of FIG. This is shown in comparison with a comparative example.

(Comparative Example 1)
An expanded metal made of aluminum having a mesh size of 5 mm × 10 mm similar to that in Example 1 was prepared and cut into a disk shape with a target of 99 mm in diameter without performing a flattening process, and an expanded metal without a flattening process It was set to 9.

  A cross-sectional view of the sample of Comparative Example 1 is shown in FIG. The transparent perforated resin plate 6 on the back air layer side was the same as in Example 1.

5 and 6 are also conceptual diagrams for explanation, and the size and the like of the expanded metal are not in accordance with the actual size.

  A transparent fluororesin thin film 5 similar to that of Example 1 is prepared, and is sandwiched between an expanded metal 9 without flattening and the transparent perforated resin plate 6, and a translucent film vibration absorbing plate sample for measuring normal incident sound absorption coefficient The result of measuring the normal incidence sound absorption coefficient in the same manner as in Example 1 is shown as a curve b in FIG.

(Comparative Example 2)
As in Example 1 and Comparative Example 1, normal incident sound absorption was performed on a sample containing only the fluorine-based transparent resin thin film 5 without sandwiching the fluorine-based transparent resin thin film 5 between the expanded metal made of aluminum and the transparent perforated resin plate. The result of measuring the rate is also shown by curve c in FIG.

  As is clear from FIG. 7, the fluorine-based transparent resin thin film 5 is sandwiched between only the fluorine-based transparent resin thin film 5 (curve c in the figure) and the aluminum expanded metal 9 without flattening and the transparent perforated resin plate 6. In this case (curve b in the figure), it is apparent that the sound absorption rate is insufficient and cannot be a sound absorbing material.

  However, as shown in FIG. 5, when the fluorine-based transparent resin thin film 5 is sandwiched between the aluminum expanded metal 4 and the transparent perforated resin plate 6 that have been flattened in advance, the curve a in FIG. Thus, the sound absorption characteristics were improved dramatically.

  A plate-like body having a size of 500 mm × 2000 mm was prepared from an expanded metal 4 made of aluminum that had been subjected to a flattening process with a mesh size of 5 mm × 10 mm.

  Further, the transparent perforated resin plate 6 having a thickness of 1.5 mm, an opening diameter of 10 mm, an opening center distance (pitch) of 16 mm, an opening angle of 60 degrees, and an opening ratio of 35%. A transparent perforated resin plate 6 having a size of 500 mm × 2000 mm was prepared.

  Between the aluminum expanded metal 4 and the transparent perforated resin plate 6 that have been flattened with a mesh size of 5 mm × 10 mm, the fluorine-based transparent resin thin film 5 having a thickness of 12 μm similar to that in Example 1 is sandwiched, The light transmissive membrane vibration sound absorbing plate 11 of the present invention was used.

  FIG. 8 shows a plan view of the translucent film vibration absorbing plate 11 of the present invention as seen from directly above. As is apparent from the figure, the aluminum expanded metal 4 side subjected to the flattening process is located on the upper surface (sound source side).

  FIG. 9 is a cross-sectional view taken along the line aa in FIG. 8 and 9 are explanatory diagrams, and the size and shape of the components are not in proportion to actual size.

  As shown in a cross-sectional view in FIG. 11, a casing 15 was manufactured that was 500 mm (width) × 2000 mm (length) × 100 mm (depth) and only the upper surface was opened. The bottom surface of the casing 15 is a transparent resin sound insulating plate 14 having a thickness of 5 mm, and the side wall 13 is processed into a box shape using a steel plate having a thickness of 1 mm. )).

  The translucent membrane vibration sound absorbing plate 11 of the present invention was fixed so as to close the upper surface (open surface) of the casing 15, and the translucent membrane vibration sound absorbing panel 16 of the present invention was manufactured.

  With respect to the translucent membrane vibration absorption panel 16 of the present invention, the results of measuring the reverberation chamber method sound absorption rate according to JIS A 1409-1998 are shown in the curve of FIG.

  As is clear from FIG. 12, the translucent film vibration absorbing plate 11 of the present invention of Example 2, that is, the translucent sound absorbing panel 16 of the present invention also showed good sound absorption characteristics.

  In the second embodiment, only one fluorine-based transparent resin thin film 5 is provided as shown in FIG. 9, but two fluorine-based transparent resin thin films 5 may be used as shown in FIG. Absent. In this case, the fluorine-based transparent resin thin film 5 on the outer side (the side not sandwiched by the flattened aluminum expanded metal 4) is disposed so as to be on the inner side of the translucent sound absorbing panel 16 of the present invention. However, it is important for protecting the fluorine-based transparent resin thin film 5. By using two sheets, the sound absorption characteristics generally show an improvement trend.

  In the translucent film vibration absorbing plate of the present invention, not only its sound absorption characteristics but also light transmittance is an important element in characteristics.

  The translucent membrane vibration absorbing plate 11 of the present invention used in Example 2, that is, a flattened aluminum expanded metal 4 having a mesh size of 5 mm × 10 mm, and a transparent perforated resin plate having a hole diameter of 10 mm The light transmittance of the translucent film vibration sound absorbing plate 11 of the present invention using 6 was measured using an illuminometer.

The illuminometer is a model made by HIROKI (made in Japan): LUX Hi TESTER 3421 (light receiving part: about 40 mmφ).

  The light transmittance was determined by measuring the illuminance when the translucent film vibration absorbing plate 11 (A) of the present invention was placed in front of the illuminometer light receiving part and when it was not placed. Natural light was used as the light source.

    The result of having calculated | required the light transmittance of the translucent type | mold film vibration sound-absorbing board 11 (A) of this invention using the illuminance meter to A of Table 1 is shown.

(Comparative Example 3)
As a comparative example of Example 3, a conventional light-transmitting membrane vibration absorbing plate, that is, an aluminum expanded metal 4 having a mesh size of 5 mm × 10 mm and having a mesh size shown in the sectional view of FIG. The transparent transparent resin thin film 5 was sandwiched between the expanded metal 17 made of aluminum having a flattened size of 4 mm × 8 mm to prepare a conventional translucent film vibration sound absorbing plate 18 (B).

The result of obtaining the light transmittance by the same method as in Example 3 is shown in B of Table 1.

  As is apparent from Table 1, it is clear that the light transmittance is superior to the translucent film vibration sound absorbing plate A of the present invention using a transparent perforated plate as one plate-like body.

  By using two transparent perforated plates as the plate-like body, the light transmittance is further improved, but when exposed to the environment of the noise barrier for roads for a long time, adsorption of exhaust gas dust due to static electricity etc. Since the amount is large, the light transmittance deteriorates at an early stage, which is not practical.

  By using the translucent film vibration absorbing plate and translucent sound absorbing panel of the present invention, the soundproofing for roads and railways has not only the sound absorbing characteristics but also the translucency through the sound absorbing panel and the visibility through the sound absorbing panel as necessary. May be used for walls.

It is explanatory drawing of an expanded metal, and is a front view of one mesh. It is aa sectional drawing of FIG. It is a figure which shows the state which roll-rolled the state of FIG. 2 and gave the planarization process. It is a figure explaining the sound absorption mechanism of the translucent type | mold film vibration sound-absorbing board and translucent type sound-absorbing panel of this invention. It is sectional drawing of the translucent type | mold film vibration sound-absorbing plate sample for normal incidence sound absorption coefficient measurement which performed the planarization process. It is sectional drawing of the translucent type | mold film vibration sound-absorbing plate sample for normal incidence sound-absorbing rate measurement using the expanded metal without a planarization process. It is a figure which shows a normal incidence sound absorption coefficient. It is a top view of the state which looked down at the translucent type | mold film vibration sound-absorbing board of this invention from right above. It is aa sectional drawing of FIG. It is a figure at the time of using two fluorine-type transparent resin thin films. It is a figure explaining the translucent sound absorption panel of this invention. It is a figure which shows the reverberation room method sound absorption coefficient. It is a figure which shows the conventional translucent type | mold film vibration sound-absorbing board which pinched | interposed the fluorine-type transparent resin thin film with the two expanded metal which performed the planarization process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 One network of expanded metal 2 Fluorine type transparent resin thin film 3 Translucent type membrane vibration sound absorbing plate 4 Flattened aluminum expanded metal 5 Fluorine type transparent resin thin film 6 Transparent perforated resin plate 7 Transparent resin sound insulating plate 8 Transmissive membrane vibration sound absorbing plate sample 9 for normal incident sound absorption measurement 9 Aluminum expanded metal 10 without flattening processing Translucent membrane vibration sound absorbing plate sample 11 for normal incidence sound absorption measurement 11 Plate 12 Translucent membrane vibration sound absorbing plate 13 using two fluorine-based transparent resin thin films 13 Side wall 14 Transparent resin sound insulating plate 15 Housing 16 Translucent sound absorbing panel 17 of the present invention Made of flattened aluminum Expanded metal 18 Conventional translucent membrane vibration sound absorbing plate T Expanded metal original thickness t Expanded metal flattened thickness G Sound source S Sound wave A Back air layer BP Back

Claims (2)

  In a translucent membrane vibration absorbing board, wherein a transparent resin thin film is sandwiched between two plates having a large number of openings, one of the two plates has an aluminum expanded metal in advance. The flattening rate is in the range of 0.45% to 0.60%, the other is the hole diameter of 5mm to 15mm and the plate thickness is in the range of 1mm to 3mm, and A light-transmitting membrane vibration sound-absorbing plate, which is a transparent perforated resin plate having an aperture ratio in the range of 20% to 50%.   A transparent resin sound insulating plate is disposed on the sound source side and the opposite sound source side of the translucent membrane vibration sound absorbing plate according to claim 1, and an air layer is formed by holding them with a frame member. A translucent sound-absorbing panel characterized by that.