JP6377419B2 - Sound absorbing structure - Google Patents

Description

  The present invention relates to a sound-absorbing structure effective mainly for low-frequency sound absorption.

  Conventionally, in order to absorb sound in a low frequency band around 100 Hz in a room such as a building, a porous plate member is formed by interposing a back air layer on the wall surface of the room as shown in FIG. Or a structure in which a resonator is embedded in a wall as shown in FIG. 4B is known.

JP 07-302087 A (Patent No. 2785687) JP 2014-052539 A

  However, in the sound absorbing structure shown in FIG. 4A as a conventional example, the sound absorbing effect in the low frequency range cannot be improved unless the thickness of the back air layer is sufficiently increased, and as a conventional example, FIG. The sound absorbing structure shown in (B) has a problem that the sound absorbing effect is low.

  In addition, in recent years, sound absorbers utilizing air column resonance for sound absorption in a low frequency band are known. For example, the sound absorbing structure described in Patent Document 1 has a plurality of cavities, the openings are arranged adjacent to each other, and the longitudinal cavities are arranged along a wall or the like. However, since this sound absorbing structure is one in which openings between a plurality of cavities are adjacent and energy is consumed by coupled vibration, sound is not absorbed by a single sound absorbing structure.

  Further, in the sound absorbing structure described in Patent Document 2, a cylindrical cavity is provided inside the wall to resonate with the air column, and a sound absorbing material is disposed in the opening. However, in this sound absorbing structure, since a cavity is provided inside the wall, there is a problem that the manufacturing cost increases and there is no degree of freedom to freely move the position of the sound absorbing body according to the reverberation performance of the indoor space. The sound absorbing structure according to the present invention has been proposed in order to solve such problems.

The gist for solving the above-mentioned problems of the sound-absorbing structure according to the present invention is to provide a bottomed cylindrical body having an elongated cavity, a sound-absorbing material provided at one end side opening of the cylindrical body, and the cylinder A sound absorbing body is constituted by gap maintaining means for providing a required gap between one end opening end surface of the body and the surface of the indoor structural body (referring to any one of floor, wall, and ceiling, the same applies hereinafter), The sound absorber is disposed so that the longitudinal axis of the hollow portion and the surface of the indoor structure are orthogonal to each other, and a gap is provided between the one end-side opening end surface of the cylindrical body and the surface of the indoor structure. A gap is provided by the maintaining means, and the sound absorbing material is wound in a cylindrical shape in parallel with the barrel portion of the cylinder body in a gap between the opening end surface on one end side of the cylinder body and the surface of the indoor structural body. It has been done .

As the material of the sound absorbing material, flow resistance (Ns / m ^Three ) Is 300 to 100, thickness is 1.7 to 1.4 mm, and areal density (Kg / m) ² ) Is 2.6 to 1.9.

The gap between the one end side opening end face of the cylindrical body and the surface of the indoor constituent body is 30 mm .

  Furthermore, the sound absorbing material is a resistance material.

  In addition, the installation position of the sound absorber is arranged near the wall when it is arranged on the floor which is an indoor component.

According to the sound- absorbing structure of the present invention, the sound- absorbing material is wound in a cylindrical shape in a gap between the opening end face on one end side of the cylinder and the surface of the indoor constituent body in parallel with the trunk of the cylinder. As a result, the opening at one end of the sound absorber that causes air column resonance is narrowed (30 mm) close to the longitudinal axis of the cavity and the wall surface or floor surface, thereby increasing the particle velocity around the opening. Since the sound absorbing material (resistive material) is provided in the opening, the vibration energy of the air particles is efficiently converted into thermal energy by the friction between the air particles and the sound absorbing material (resistive material) that vibrates vigorously. It has an excellent effect that it is converted and a high sound absorption effect is obtained.

  In addition, the sound absorber functions simply by maintaining a gap on the surface of the indoor structure, and further, if it is placed near the wall of the floor, the sound absorbing effect is further increased. It has a high degree of freedom in moving the position, and can effectively absorb sound in a low frequency band according to various indoor shapes and space sizes.

It is the longitudinal cross-sectional view (A) which shows Example 1, 2 of the sound-absorbing structure 1 which concerns on this invention, (B). It is a schematic plan view (A), (B), (C) which shows the example which arranges the several sound absorption body 2 in the reverberation chamber 9 in the sound absorption structure 1. FIG. It is a longitudinal section (A) and (B) of a sound absorption structure concerning other comparative examples for comparing with sound absorption power of sound absorption structure 1 concerning the present invention. The sound absorber when the material of the cylinder is placed in the order from the top in the drawing with the opening 2c of the sound absorber 2 made of vinyl chloride, paper, hot-dip galvanized steel plate and the material b is added to the sound absorber 3. It is a characteristic curve figure which shows the sound-absorbing power per 1 of 2 bodies. The sound absorber when the material of the cylinder is placed in the downward direction with the opening 2c of the sound absorber 2 made of vinyl chloride, paper, hot-dip galvanized steel sheet from the top in the figure, and the material b of the sound absorber 3 is added. It is a characteristic curve figure which shows the sound-absorbing power per 1 of 2 bodies. 1A and 1B, the first and second embodiments of the sound absorbing structure 1 according to the present invention, and the measurement of the sound absorbing force of the sound absorbing structure according to another comparative example shown in FIG. It is a characteristic curve figure which shows a result. It is a longitudinal cross-sectional view (A) and (B) which shows the example of the sound-absorbing structure which concerns on a prior art example.

  As shown in FIGS. 1A and 1B, the sound absorbing structure 1 according to the present invention has an opening 2c of the sound absorbing body 2 as an indoor structure (refers to any one of a floor, a wall, and a ceiling). For example, it is installed toward the surface 4 of the floor.

  As shown in FIGS. 1 (A) and 1 (B), a sound absorbing structure 1 according to the present invention has a sound absorbing structure provided in a bottomed cylindrical body 2b having an elongated cavity 2a and one end side opening 2c of the cylindrical body 2b. The sound absorber 2 is constituted by the material 3 and gap maintaining means for providing a required gap 5 between the end face of the one end side opening 2c of the cylindrical body 2b and the surface 4 of the indoor constituent body.

  As an example, the cylinder 2b has a diameter of 200 mm, a length of 700 mm, and a material made of vinyl chloride, paper, hot-dip galvanized steel sheet. One of the openings at both ends of the cylindrical body 2b is hermetically sealed with a 9 mm thick veneer plate, and the other is the opening 2c.

  Although not shown, the gap maintaining means is a hard block made of metal or synthetic resin, and has a height of 30 mm as an example.

  As shown in FIG. 1A, the sound absorber 2 is disposed so that the longitudinal axis a of the cavity 2a and the surface 4 of the indoor structure body are orthogonal to each other, and the cylindrical body 2b. Between the end face of the one-end-side opening 2c and the surface 4 of the indoor structure to which the opening 2c is directed, for example, by the gap maintaining means such as an inclusion having a desired height (30 mm as an example) A gap 5 is provided, and is disposed, for example, at the center of the indoor floor or near the wall to form the sound absorbing structure 1.

  As shown in FIG. 1 (A), the sound absorbing material 3 is disposed so as to close the one end side opening 2c of the cylindrical body 2b in parallel with the bottom surface of the cylindrical body 2b.

Before reaching the structure of the sound absorbing structure 1, the sound absorbing force due to the air column resonance of the sound absorbing body 2 is represented by a reverberation chamber (volume 313 m ² , surface area 273 m ² ) 9 shown in FIGS. Thus, the change in the sound absorption force due to the arrangement and orientation of the sound absorber 2 is verified in advance. The reverberation chamber method sound absorption coefficient is measured in accordance with JIS A 1409 except for the test specimen, the installation method of the test specimen (sound absorber 2), and the measurement frequency. The distance between the test bodies (sound absorbers 2) was 1 m or more, 6 bodies in the center of the reverberation chamber 9, 12 bodies in the center, and 6 bodies in the outer periphery.

  The sound absorber 2, which is the test body, has a length of 700 mm and a diameter of 200 mm, and is made of vinyl chloride (thickness, 7.0 mm, weight 4.6 kg), paper (thickness 4.0 mm, weight). 1.4 kg) and hot dip galvanized steel sheet (thickness 0.5 mm, weight 2.3 kg).

Further, for example, two kinds of materials for the sound absorbing material 3 are prepared, and the material a has a flow resistance (Ns / m ³ ) of about 300, a thickness of 1.7 mm, and an areal density (Kg / m ² ). The material b has a flow resistance (Ns / m ³ ) of about 100, a thickness of 1.4 mm, and an areal density (Kg / m ² ) of 1.9.

  As a result, as shown in FIGS. 3A and 3B, the test body (sound absorber 2) has a sound absorption characteristic having a peak in the vicinity of 100 Hz regardless of the material of the resonator and the state of the opening 2c. As shown in FIG. 2A (C), when the test body (sound absorber 2) is disposed on the outer peripheral part (by the wall) of the floor, the peak is 0.1 to 0 than when it is disposed in the central part. .4 larger. The difference in the material (vinyl chloride, paper, hot-dip galvanized steel sheet) of the test body (sound absorber 2) is hardly seen except for a part.

  In addition, the difference in the sound absorption force due to the presence or absence of the sound absorbing material 3 is hardly observed in the case of the material a, but when the material b is added to the upward opening 2c, the sound absorption force peak is 0.1 to 0.1. When the material b was added to the downward opening 2c, the sound absorption peak increased by about 0.2 to 0.4 depending on the conditions. Thereby, the material b has a larger sound absorption force than the material a, and the influence of the material of the test body (sound absorption body 2) on the sound absorption force is small, and the sound absorption depends on the installation position of the sound absorption body 2 and the direction of the opening 2c. The power is very different.

  Furthermore, when the particle velocity at the opening 2c of the sound absorber 2 is measured, the particle velocity level increases remarkably when the opening 2c is brought close to the surface 4 of the indoor structure.

From the above results, as shown in FIGS. 1A and 1B, the sound absorbing structure 1 according to the present invention has an opening 2c of the sound absorbing body 2 made of vinyl chloride (diameter 200 mm, length 700 mm). Is directed downward toward the floor surface 4 which is one of the indoor components, and a gap 5 of about 30 mm is provided by the gap maintaining means, and the sound absorbing material 3 is made of the material b (flow resistance (Ns / m ^3). ) Is about 100, the thickness is 1.4 mm, and the surface density (Kg / m ² ) is 1.9).

  As shown in FIGS. 2-B (A) and (B), as a test example for comparison, the sound absorbing material 3 is not provided with the opening 11c of the sound absorber 10 facing upward, and the opening 11c. And the case where the sound absorbing material 3 (the material b) is provided. The test conditions are the same as those in the test of JIS A 1409 except for the installation method and the measurement frequency, which are arranged near the wall of the reverberation chamber 9 (FIG. 2A (C)).

As a result, as shown in FIG. 3C, when the sound absorption force (m ² ) in the low frequency band is measured, the opening 2c is directed upward, and the sound absorbing material 3 is not added to the opening 2c (FIG. 2-C). In the type A shown in B (A), the sound absorbing power is 0.3, and in the type B (FIG. 2-B (B)) in which the sound absorbing material 3 is added to the opening 2c, the sound absorbing power is 0.55. In the type C1 (FIG. 1A) according to the present invention, the sound absorption force is about 0.75, and the sound absorption structure 1 according to the present invention clearly has a larger sound absorption force.

  As another embodiment, as shown in FIG. 1B, the sound absorbing material 3 is formed in a gap 5 between the end surface of the one end side opening 2c of the cylindrical body 2b and the surface 4 of the indoor structural body. There is a type C2 that is wound in a cylindrical shape parallel to the body of the cylindrical body 2b. Although the sound absorbing structure 1 is a modified example of the type C1, in this case as well, as shown in FIG. As a result, the sound absorption force is larger than those of types A and B.

  In this way, the opening 2c of the sound absorber 2 is brought close to the surface 4 of the indoor structure (any one of the ceiling, the wall, and the floor) with a gap 5, and the opening 2c is By providing a resistance material as the sound absorbing material 3, it is possible to effectively absorb sound in a low frequency band.

  The sound absorbing structure 1 according to the present invention can be widely applied to various architectural spaces because the sound absorbing body 2 absorbs sound in a low frequency band simply by placing the opening of the sound absorbing body 2 orthogonally close to the surface 4 of the indoor structure. It can be done.

1 sound absorbing structure,
2 sound absorber, 2a cavity,
2b cylinder, 2c opening,
3 Sound absorbing material (resistance material),
4 surface,
5 Clearance,
6 rigid wall,
7 Porous material,
8 Resonator,
9 Reverberation room,
10 Sound absorber,
11a cylinder, 11b hollow part,
11c opening,
a The axis of the sound absorber.

Claims (5)

Gap maintenance that provides a required gap between the bottomed cylindrical body having an elongated cavity, the sound absorbing material provided at the opening on one end of the cylinder, and the end surface of the opening on the one end of the cylinder and the surface of the indoor structure The sound absorber is composed of the means,
The sound absorber is disposed so that the longitudinal axis of the cavity portion and the surface of the indoor structure body are orthogonal to each other, and the end surface of the one end side opening of the cylindrical body and the surface of the indoor structure body A gap is provided between the gap maintaining means,
The sound-absorbing material is wound in a cylindrical shape in parallel with the trunk portion of the cylindrical body, in a gap between the opening end face on one end side of the cylindrical body and the surface of the indoor constituent body ;
A sound-absorbing structure. As the material of the sound absorbing material, a material having a flow resistance (Ns / m ³ ) of 300 to 100, a thickness of 1.7 to 1.4 mm, and an areal density (Kg / m ² ) of 2.6 to 1.9. to use,
2. The sound absorbing structure according to claim 1, wherein The clearance between the one end side opening end face of the cylindrical body and the surface of the indoor structural body was 30 mm,
2. The sound absorbing structure according to claim 1, wherein The sound absorbing material is a resistance material;
The sound-absorbing structure according to any one of claims 1 to 3. When the sound absorber is disposed on the floor which is an indoor component, the sound absorber is disposed near the wall.
The sound-absorbing structure according to any one of claims 1 to 4, wherein:

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