JP2006328673A - Low-frequency sound absorption panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound absorption panel which is easily mountable, and exerts high sound absorbing effect in a low-frequency band. <P>SOLUTION: The sound absorption panel is formed of a box-shaped panel (4) consisting of a front surface member (1) facing a sound source, a rear surface member (2) opposed to the same, and a side frame member (3) arranged between edges of the front and rear surface members, and glass wool (5) packed in the box as a sound absorption material. The front surface member forming the box-shaped panel is a plate preferably having an area density of 0.2 to 4 kg/m<SP>2</SP>, or a flexural rigidity of 5×10<SP>-3</SP>to 100 Nm, and an area of 0.5 to 5 m<SP>2</SP>. The sound absorption material packed in the box-shaped panel is preferably formed of a fibrous sound absorption material such as the glass wool and rock wool, or a foam formed of polyethylene or polypropylene. The density of the sound absorption material is preferably set to 8 to 100 kg/m<SP>3</SP>, and more preferably set on the order of 24 kg/m<SP>3</SP>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sound absorbing panel that exhibits a high sound absorbing effect in a low frequency region.

Conventionally, as a sound absorbing panel for low frequency (63 to 200 Hz), a concrete sound absorbing panel using a sound absorbing property of a foam, for example, a porous concrete plate having an uneven shape on the surface, and a back surface of the porous concrete plate are superimposed. There has been proposed a sound-absorbing concrete plate which is made of ordinary concrete plate and in which an air storage space is partially formed between the porous concrete plate and the ordinary concrete plate (Patent Document 1). However, this has a porous surface, and the sound absorption performance is remarkably deteriorated when used outdoors, so that the weight is large and the construction is difficult.

In addition, there has been proposed a vibration control panel in which a large number of cell spaces are formed by partitioning the space between two opposing plate members and elastic powder particles are enclosed in the cell spaces (Patent Document 2). In this structure, the sound absorption effect is small at a target low frequency, the structure is complicated, and the cost is high.
Japanese Patent Laid-Open No. 10-102623 JP-A-11-217891

  This invention makes it a subject to provide the sound absorption panel which shows the high sound absorption effect at low frequency while being easy in construction in view of the above actual conditions.

  The sound absorbing panel according to the present invention is a box-shaped panel composed of a surface material directed to the sound source side, a back material facing the sound material, and a side frame material provided between the edges of the surface material and the back material. The sound absorbing material is packed in the box.

Surface material constituting the box-shaped panels, surface density 0.2~4kg / ^{m 2} or flexural rigidity 5 × ¹⁰ -3 ~100Nm, a plate of area 0.5 to 5 m ^2. If the surface density, bending rigidity, or area value is too small or too large, the sound absorption rate is lowered.

The sound absorbing material packed in the box-shaped panel is preferably a fibrous sound absorbing material such as glass wool or rock wool, or a sound absorbing material made of polyethylene or polypropylene foam. The density of the sound absorbing material is preferably 8~100kg / ^{m 3,} more preferably 24 kg / ^{m 3} approximately. If this density is too small or too large, the sound absorption rate decreases.

  The material of the plate material used for the front surface material, the back surface material, and the side frame material may be any of metal, wood board, inorganic board, plastic, and the like. The plate material may be plywood. The thickness of the surface material is preferably selected as appropriate depending on the material so as to have the above surface density. For example, when aluminum is used, 0.07 to 1.5 mm is preferable. Moreover, although the thickness of a back surface material and a side frame material is not specifically limited, 0.2-10 mm is preferable on handling.

  The sound absorbing panel according to the present invention is installed by fixing the back surface material to a wall or the like so that the surface material faces the sound source side.

  The height of the sound absorbing panel, that is, the protruding height from the wall or the like is theoretically preferably high in order to obtain an effect at a lower frequency, but is preferably about 100 mm in order to improve the finish after construction in terms of handling.

  The sound absorbing panel according to the present invention is a box-shaped panel composed of a specific surface material directed to the sound source side, a back surface material facing the specific surface material, and a side frame material provided between these edges, The sound absorbing material is enclosed in the inside, and since it has a relatively simple structure, it is lightweight, inexpensive and easy to construct, and also exhibits a high sound absorbing effect at a low frequency.

  Next, in order to specifically explain the present invention, some examples of the present invention and comparative examples for showing comparison with the examples will be given.

Example 1
In FIG. 1, a surface material (1) made of an aluminum plate, a back material (2) opposite to the surface material, and a side frame provided between the edges of the surface material (1) and the back material (2). A box-shaped panel (4) is constructed from the material (3). The surface material (1) has a size of 900 mm × 900 mm × 1 mm, and thus has an area of 0.81 m ² . The surface density of the surface material (1) is 2.7 kg / m ² and the bending rigidity is 6.4 Nm. The back material (2) has a size of 900 mm × 900 mm × 9 mm, the side frame material (3) has a thickness of 9 mm, and the box-shaped panel (4) has a height of 100 mm.

Glass wool (5) with a density of 24 kg / m ³ is enclosed in the box-shaped panel (4) as a sound absorbing material so as to fill the interior. The sound absorbing panel thus constructed is installed on the floor (6) so that the surface material (1) faces the sound source side.

Examples 2-3 and Comparative Examples 1-3
The surface material (1) is the same as that of Example 1 except that the material shown in Table 1 was used.

Sound Absorption Rate Measurement The sound absorption rate was measured in accordance with JIS A 1409 (Method for measuring reverberation chamber method sound absorption rate). That is, twelve sound absorbing panels of Example 1 were arranged adjacent to each other on the floor of a reverberation chamber (volume: 200 m ³ ), 1.5 m away from the wall, so that the surface material (1) faced the sound source side. . With this structure, two speakers as sound sources are installed near the wall in the reverberation room at intervals of 3.5 m, and five microphones are 1.5 m from the sound absorbing panel, 1.5 m from the wall and floor, and from the sound source. The sound absorption coefficient was measured at a temperature of 20 and a relative humidity of 50%.

  For the sound absorbing panels of Examples 2 to 3 and Comparative Examples 1 to 3, the sound absorption rate was measured by the same operation. However, the number of sound absorbing panels of Comparative Example 3 was 72.

The obtained sound absorption coefficient is shown in the graphs of Table 1, FIG. 2 and FIG. Moreover, the average value of the sound absorption rate in a low frequency area (63-200 Hz) is shown in the graph of FIG. 3 and FIG.

  As apparent from Table 1 and FIGS. 2 to 5, the sound absorbing panel according to the present invention exhibits a high sound absorbing effect in the low frequency region (63 to 200 Hz).

It is sectional drawing which shows the structure of a sound absorption panel. It is a graph which shows the relationship between a frequency and a sound absorption coefficient. It is a graph which shows the average value of the sound absorption rate in a low frequency area | region. It is a graph which shows the relationship between a frequency and a sound absorption coefficient. It is a graph which shows the average value of the sound absorption rate in a low frequency area | region.

Explanation of symbols

(1) Surface material
(2) Back material
(3) Side frame material
(4) Box-type panel
(5) Glass wool

Claims (2)

A box-shaped panel is composed of a surface material directed to the sound source side, a back material facing the sound source, and a side frame material provided between each edge of the surface material and the back material, and the sound absorbing material is contained in the box. it it is packed, acoustical panel, wherein the surface material is a sheet of surface density 0.2~4kg / ^{m 2} or flexural rigidity 5 × ¹⁰ -3 ~100Nm, area 0.5 to 5 m ^2. The sound absorbing panel according to claim 1, wherein the sound absorbing material is a fibrous sound absorbing material or a foam sound absorbing material.

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