JP5167751B2 - Sound absorption structure - Google Patents

Description

  The present invention relates to a technique for absorbing sound.

  As a sound absorber that absorbs sound using resonance, for example, there are sound absorbers disclosed in Patent Documents 1 and 2. The sound absorber disclosed in Patent Document 1 is attached to a plate-like member in a state where the resonance box is faced down. In addition, the plate-like member is provided with a vent hole that leads to a space formed by the plate-like member and the resonance box, and the space formed by the plate-like member and the resonance box functions as a Helmholtz resonator. . The sound absorber is attached to the wall of the room so that the plate-like member provided with the air holes faces the interior of the room. Moreover, in the sound absorber disclosed in Patent Document 2, an air chamber is formed between the flat plate and the molded plate by overlapping the flat plate and the molded plate formed on the unevenness. The air chamber communicates with a hole provided in the flat plate and functions as a Helmholtz resonator. The sound absorber is arranged at a distance from the room boundary of the room so that the flat plate side on which the hole is provided faces the interior direction of the room.

Japanese Patent Laid-Open No. 10-227084 Japanese Patent Laid-Open No. 10-18471

  According to the sound absorber disclosed in Patent Documents 1 and 2, the opening of the space functioning as a Helmholtz resonator is directed to the sound field, and absorbs the sound of the sound field. However, each of the sound absorbers has a problem that dust and dust easily enter the resonator through the opening because the opening of the space functioning as a Helmholtz resonator is directed toward the sound field. In addition, since the opening is directed to the inside of the room, there is a risk that an infant or the like may get injured by putting a finger in the opening when the opening is arranged in a low-rise part of the wall surface.

  The present invention has been made under the above-described background, and an object of the present invention is to provide a technique that makes it possible to suppress foreign matter from entering through an opening of a resonance chamber while absorbing sound by resonance. .

In order to solve the above-described problem, the present invention provides a sound absorber that includes an air column as an air layer between an upper surface portion and a lower surface portion facing each other, and an opening connected to the air layer is provided in the upper surface portion. has the upper surface portion relative to the chamber boundaries of the sound field is placed facing a space between the chamber boundary and the upper surface portion, the sound absorbing structure in which the space is in communication with the sound field provide.

In the present invention, the upper surface portion may be plate-shaped .
In the present invention, the air layer includes a plurality of air layers, and the upper surface portion is provided with an opening portion connected to the air layer for each air layer, and the position of the opening portion in the upper surface portion is determined for each air layer. It may be different.
In the present invention, a plurality of concave portions and a plurality of convex portions may be provided on the side opposite to the chamber boundary side as viewed from the chamber boundary .
Moreover, in this invention, the porous layer formed with the porous raw material may be provided in the said recessed part.
In the present invention, the opening of the recess may be closed by a plate-like or film-like vibrating member that is deformed by an external force.

  According to the present invention, foreign matter can be prevented from entering from the opening of the resonance chamber while absorbing sound by resonance.

  FIG. 1 is a schematic view of a sound absorber 2 according to an embodiment of the present invention, and FIG. 2 is a side view of the sound absorber 2 viewed from the direction of arrow A in FIG. The sound absorber 2 is roughly composed of an upper surface portion 21, a lower surface portion 23, and a separation wall portion 24.

The upper surface portion 21 and the lower surface portion 23 are made of wood and have a rectangular and plate shape. Further, the upper surface portion 21 and the lower surface portion 23 have substantially the same size.
The separation wall portion 24 is made of wood, and includes a plurality of convex portions 25 having a convex cross section and a plurality of concave portions 26 having a concave cross section. In the separation wall part 24, each convex part 25 and each concave part 26 are extended in the direction orthogonal to the cross section of each shape (namely, the direction along the surface of the upper surface part 21 and the lower surface part 23). Further, in each of the convex portions 25 and the concave portions 26, the upper side portion 25A of the convex portion 25 and the bottom side portion 26A of the concave portion 26 are both flat.

  In the sound absorber 2, the separation wall portion 24 is disposed between the upper surface portion 21 and the lower surface portion 23 facing each other, the bottom side portion 26 </ b> A of the separation wall portion 24 is fixed to the lower surface portion 23, and the upper side portion of the separation wall portion 24. 25A is fixed to the upper surface portion 21. As described above, in the sound absorber 2, the upper surface portion 21 and the lower surface portion 23 are sandwiched between the upper surface portion 21 and the lower surface portion 23, and the upper surface portion 21 and the lower surface portion 23 are fixed to the separation wall portion 24. An air layer 30 </ b> B along the convex portion 25 and an air layer 30 </ b> A along the concave portion 26 are formed between the lower surface portion 23.

FIG. 3 is a top view of the sound absorber 2. As shown in FIG. 3, the upper surface portion 21 has an opening connected to the air layer 30 </ b> A so that the air layer 30 </ b> A becomes a resonance tube that absorbs sound. A portion 21A is provided for each air layer 30A.
FIG. 4 is a cross-sectional view taken along line BB of the top view shown in FIG. Show. As shown in the figure, the air layer 30A in which the opening 21A is formed (open tube = a tube having both ends at the open end) has an open tube α (FIG. 4) having a length (L1 + L2) from the viewpoint of acoustics. (Α)), an open tube β of length L2 (FIG. 4 (β)), and an open tube γ of length L1 (FIG. 4 (γ)). Here, the open tube α resonates with a sound wave with a wavelength λα = 2 × (L1 + L2), the open tube β resonates with a sound wave with a wavelength λβ = 2 × L2, and the open tube γ has a wavelength λγ = 2 × L1. In the air layer 30A, while the sound waves having the wavelengths λα, λβ, and λγ repeat vibration, the friction on the wall surface of the separation wall portion 24 and the viscous action between the air particles at the opening end are performed. Thus, energy can be consumed and sound waves centered at wavelengths λα, λβ, and λγ can be attenuated. Note that the solid curve in the tube in FIGS. 4 (α) to 4 (γ) indicates the distribution of the particle velocity amplitude of the sound wave resonating in the tube.

  Furthermore, since sound waves having wavelengths λα, λβ, and λγ are re-radiated from the opening 21A of the air layer 30A with a time delay, sound waves that are out of phase with the incident sound are radiated to the outside of the sound absorber 2. This can also reduce the sound generated by the sound waves having the wavelengths λα, λβ, and λγ. That is, the sound absorber 2 can efficiently attenuate sound waves centered on three types of wavelengths with one air layer 30A, and can also attenuate sound waves that are attenuated according to the position where the opening 21A is formed. It can be adjusted.

Next, a method for arranging the sound absorber 2 in the room will be described. In the present embodiment, the sound absorber 2 is directed to the wall surface (or boundary surface) side of the room whose upper surface 21 is a sound field, and a space is formed between the wall surface (boundary surface) and the sound absorber 2. So that it is fixed to the wall.
FIG. 5 is an exploded view of the fixing member 3 for fixing the sound absorber 2 to the wall surface 10 (room boundary) of the room. The fixing member 3 is formed by a columnar member 31 and a hook-and-loop fastener 32. The material of the columnar member 31 is a synthetic resin, and is formed in the shape of a square column. Further, the hook-and-loop fastener 32 includes a hook part 32A that is a cloth with hook-shaped protrusions on one side and a pile part 32B that is a pile-woven cloth. A collar portion 32A is bonded to one of two opposing surfaces of the columnar member 31, and a pile portion 32B is bonded to the other end surface.

And the pile part 32B is adhere | attached on the four corners of the upper surface part 21 in the sound-absorbing body 2, and the collar part 32A is adhere | attached in the position which fixes the sound-absorbing body 2 in the wall surface 10. FIG. Note that the position of the flange portion 32 </ b> A bonded to the wall surface 10 is the same as the positions of the four corners of the upper surface portion 21 when the upper surface portion 21 is abutted with the position where the sound absorber 2 is fixed.
When fixing the sound absorber 2 to the wall surface 10, first, the pile portion 32 </ b> B bonded to the fixing member 3 is butted against the flange portion 32 </ b> A bonded to the wall surface 10. Thereby, the hook-shaped protrusion of the hook part 32A is entangled with the pile part 32B, and the fixing member 3 is fixed to the wall surface 10.
Next, each of the pile portions 32 </ b> B bonded to the four corners of the sound absorber 2 is butted against the flange portion 32 </ b> A bonded to the fixing member 3 fixed to the wall surface 10. Then, the hook-shaped protrusions of the hook part 32 </ b> A are entangled with the pile part 32 </ b> B bonded to the upper surface part 21, the sound absorber 2 is fixed to the wall surface 10, and the fixing member 3 is interposed between the upper surface part 21 and the wall surface 10. A space (air layer) is obtained by the height.

  As described above, when sound is generated in the room with the space between the wall surface 10 and the upper surface portion 21 in a state where the upper surface portion 21 side of the sound absorber 2 is directed to the wall surface 10, the sound is emitted in the room. Among the sound waves, low-frequency sound waves enter the space between the upper surface portion 21 and the wall surface 10. When the sound wave enters the space between the upper surface part 21 and the wall surface 10, the energy of the sound wave is consumed and the sound is absorbed by the air layer 30A having the opening part 21A. Here, the space between the upper surface portion 21 and the wall surface 10 is sandwiched between the two boundary surfaces of the upper surface portion 21 and the wall surface 10, and the sound pressure is higher than in the case where the sound absorber 2 is not disposed. Therefore, the energy of the sound wave input to the air layer 30A is increased, and the sound absorption efficiency is improved.

  6 and 7 show that (1) when the sound absorber 2 is not arranged in the room, (2) the space between the opening 21A and the wall surface with the opening 21A of the sound absorber 2 facing the wall surface of the room. (3) Each reverberation time in the case where a space is provided between the lower surface portion 23 and the wall surface with the opening 21A of the sound absorber 2 facing the inside of the room (FIG. 6A, FIG. 7 (a)) and the average sound absorption coefficient (FIG. 6 (b), FIG. 7 (b)). In this measurement, the floor area of the room is 24.3 square meters, the volume of the room is 65.1 cubic meters, and the surface area of the room is 103 square meters.

As shown in FIGS. 6 and 7, when the reverberation time and the average sound absorption rate are compared under the conditions (1) to (3), when the sound absorber 2 is not arranged in the room (1), When the sound absorbing body 2 is arranged so that there is a space between the wall surface of the room (in the cases (2) and (3)), mainly the sound in the low sound range (125 Hz to 250 Hz) is absorbed.
Further, when the case of (2) is compared with the case of (3), in the case of (2) which is an embodiment of the present invention, the sound absorbing power near 500 Hz is slightly increased. As described above, the measurement result confirms that when the sound wave enters between the vibrating part 25 and the wall surface, the sound wave energy is consumed and the sound is absorbed by the air layer 30A having the opening 21A. In addition, the space between the vibration part 25 and the wall surface 10 is sandwiched between two boundary surfaces of the vibration part 25 and the wall surface 10, and the sound pressure is higher than in the case where the sound absorber 2 is not disposed. Therefore, it is suggested that the energy of the sound wave input to the air layer 30A is increased and the sound absorption efficiency is improved.

  Moreover, according to this embodiment (in the case of (2)), since the surface (the bottom surface of the sound absorber 2) facing the interior direction of the room in the sound absorber 2 has a planar shape, various designs are used. The interior of the room can be optimally designed according to the user's preference.

[Modification]
As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, It can implement with another various form. For example, the present invention may be implemented by modifying the above-described embodiment as follows.

In the above-described embodiment, the air layer 30A is an open tube, and both ends in the longitudinal direction of the air layer are open. However, by closing the side surfaces of the sound absorber 2 with members, The opening may be closed, or only one of the openings may be closed. In the embodiment described above, the distance from both ends in the longitudinal direction of the air layer 30A to the opening 21A may be the same for each of the plurality of air layers 30A. In the embodiment described above, the shape of the opening 21A may be a circle, a polygon, or a slit instead of a rectangle.
In the above-described embodiment, the air layer 30A is configured as a resonance tube that absorbs sound. However, a plurality of openings 21A connected to the air layer 30A are provided along the recess 26 to use Helmholtz resonance. You may comprise so that it may be a perforated board.

  In the present invention, the material of the upper surface portion 21, the lower surface portion 23, and the separation wall portion 24 is not limited to wood, and may be other materials such as synthetic resin and metal. Further, the material may be different for each member, such as the upper surface portion 21 and the lower surface portion 23 being wood and the separation wall portion 24 being metal.

  In the present invention, as shown in FIG. 8, a porous layer 27 made of a porous material may be provided on the lower surface portion 23 of the sound absorber 2. According to this configuration, when the porous layer 27 is directed to the side opposite to the wall surface 10 (that is, the inside of the room), the sound in the middle and high range generated in the room can be absorbed by the porous layer 27.

In the embodiment described above, the sound absorber 2 has a configuration in which the separation wall portion 24 is sandwiched between the upper surface portion 21 and the lower surface portion 23. However, as shown in FIG. The sound absorber 2 may be formed by only the wall portion 24 and the upper surface portion 21. According to this configuration, when the separation wall portion 24 is directed to the opposite side of the wall surface 10, the high frequency sound generated in the room is reflected by the uneven portions of the separation wall portion 24, and the high frequency sound is diffused. it can.
Further, as shown in FIG. 10, the separation wall portion 24 and the upper surface portion 21 are bonded without providing the lower surface portion 23, and in the above-described embodiment, the air layer 30 </ b> B is formed of a porous material. You may make it arrange | position the porous layer 27 made. Even in this configuration, when the separation wall portion 24 is directed to the side opposite to the wall surface 10, the high-frequency sound generated in the room can be absorbed by the porous layer 27.
In the present invention, a porous plate 27 using Helmholtz resonance or a sound absorbing mechanism using tube resonance may be provided instead of the porous layer 27 shown in FIGS.

  Further, in the present invention, instead of the lower surface portion 23, a film-like member in which a material that is deformed when a force is applied is formed into a thin film shape is replaced with a plurality of bottom portions 26A by an adhesive applied to the bottom portion 26A. You may adhere | attach in the state which applied tension. According to this configuration, when an air layer is obtained between the membrane member and the separation wall portion 24 and the membrane member is directed toward the inside of the room, the membrane member vibrates and a low sound is absorbed. Further, instead of the film-like member, a plate-like member in which an elastic material is formed in a plate shape may be bonded to the base portion 26A. Even in this configuration, when an air layer is obtained between the plate-like member and the separation wall portion 24 and the plate-like member is directed to the inside of the room, the plate-like member vibrates and a low sound is absorbed.

In the present invention, as shown in FIG. 11, a plurality of sound absorbers 2 may be arranged, and the sound absorbers 2 may be arranged on the wall surface 10 so that there is a gap between the sound absorbers 2.
In addition, in the plurality of sound absorbers 2 provided with the gaps, a finishing material having a sound transmission property and a sound distribution resistance with respect to the sound (surfaces facing the interior of the room (the bottom surface of the sound absorber 2)) ( For example, a plurality of sound absorbers covered with a jersey net, curtain cloth, non-woven fabric, mesh sheet, and the like may be configured to visually form one surface. According to this configuration, the sound absorbing force is further improved by the distribution resistance of the finishing material.
Further, when a plurality of sound absorbers 2 are arranged on the wall surface 10, the sound absorber 2 may be inclined with respect to the wall surface 10 as shown in FIG. 12. According to this configuration, the sound generated inside the room wraps around the outer surface of the sound absorber 2 and reaches the space between the wall surface 10 and the upper surface portion 21, and is absorbed by resonance of the air layer 30A.
Moreover, in this invention, as shown in FIG. 13, you may arrange | position the sound-absorbing body 2 and the reflecting plate 4 which reflects a sound on the wall surface 10 with a clearance gap. Further, in the configuration in which the sound absorbing body 2 and the reflecting plate 4 are arranged in this way, the sound absorbing body 2 and the reflecting plate 4 are inclined with respect to the wall surface 10 as in the arrangement shown in FIG. You may arrange in. Further, in the configuration in which the sound absorbing body 2 and the reflecting plate 4 are arranged on a plurality of wall surfaces, a sound-transmitting material such as punching metal is provided in a gap between the sound absorbing body 2 or the reflecting plate 4 arranged next to the sound absorbing body 2. Good members may be placed.
Moreover, in the structure which arrange | positions the sound-absorbing body 2 and the reflecting plate 4 on a wall surface, as shown in FIG. 14, you may make it arrange | position on the wall surface 10 by making the inclination of the sound-absorbing body 2 and the reflecting plate 4 differ. .
Further, when the sound absorber 2 and the reflector 4 are arranged in the room, they may be arranged on the ceiling or floor.

Further, in the present invention, the above-described columnar member may be made to be a telescopic shape so that the user can freely adjust the distance between the upper surface portion 21 and the wall surface 10. FIG. 15 is a diagram (side view) showing an example of the extendable columnar member 33. As shown in FIG. 15, the columnar member 33 includes a base portion 33A and an adjustment portion 33B. The base 33A has a shape in which one opening of the circular tube is closed, and an internal thread is cut on the inner peripheral surface. Moreover, the external appearance of the adjustment part 33B is cylindrical, and the external thread is cut off on the outer peripheral surface. Since the male screw provided in the adjusting portion 33B is configured to mesh with the female screw of the base portion 33A, when the adjusting portion 33B is rotated, the bottom surface of the base portion 33A (the side where the opening portion is not provided in the base portion 33A). In the adjusting portion 33B, it is possible to adjust the distance to the end surface on the side opposite to the side entering the opening side of the base portion 33A.
And if the columnar member 31 of embodiment mentioned above is changed into this columnar member 33, the user can change the distance between the upper surface part 21 and the wall surface 10 freely, and can adjust a sound absorption characteristic arbitrarily. The above-described configuration for adjusting the distance between the wall surface 10 and the upper surface portion 21 is an example, and the configuration for adjusting the distance between the wall surface 10 and the upper surface portion 21 is not limited to the above-described configuration.

  In the present invention, the shape of the air layer for sound absorption is not limited to the shape described above. For example, as illustrated in FIG. 16, when the shape of the separation wall portion 24 is a lattice shape and the separation wall portion 24 is sandwiched between the upper surface portion 21 and the lower surface portion 23, a plurality of air chambers may be obtained. Good. Moreover, in this structure, as shown in FIG. 17, you may make it provide the opening part 21A connected to each air chamber in the upper surface part 21. As shown in FIG.

  In addition, the sound absorber (sound absorbing structure) in the present embodiment can be arranged in various acoustic chambers that control acoustic characteristics. Here, the various acoustic rooms include a soundproof room, a hall, a theater, a listening room for audio equipment, a room such as a conference room, a space for various transportation equipment, a housing for speakers, musical instruments, and the like.

1 is an external view of a sound absorber according to an embodiment of the present invention. It is a side view of the sound absorber according to the embodiment. It is a top view of the sound absorber according to the embodiment. It is a figure for demonstrating the principle of sound absorption. 4 is an exploded view of the fixing member 3. FIG. It is a measurement result of reverberation time and average sound absorption rate when the sound absorber 2 is arranged in a room. It is the graph showing the reverberation time when the sound-absorbing body 2 is arrange | positioned in a room, and the measurement result of an average sound absorption rate. It is a side view of the sound-absorbing body which concerns on the modification of this invention. It is a side view of the sound-absorbing body which concerns on the modification of this invention. It is a side view of the sound-absorbing body which concerns on the modification of this invention. FIG. 3 is a diagram illustrating an arrangement example of a sound absorber 2. FIG. 3 is a diagram illustrating an arrangement example of a sound absorber 2. It is the figure which showed the example of arrangement | positioning of the sound absorber 2 and the reflecting plate 4. FIG. It is the figure which showed the example of arrangement | positioning of the sound absorber 2 and the reflecting plate 4. FIG. It is the figure which showed the columnar member which concerns on the modification of this invention. It is the figure which showed the separation wall part which concerns on this invention. It is an external view of the sound absorber which concerns on the modification of this invention.

Explanation of symbols

2 ... sound absorber, 3 ... fixing member, 4 ... reflector, 10 ... wall surface, 21 ... upper surface, 21A ... opening, 23 ... lower surface, 24 ··· Separation wall, 25 ... convex, 25A ... upper side, 26 ... concave, 26A ... bottom, 27 ... porous layer, 30A, 30B ... air layer, 31 ... Columnar member, 32 ... Hook, 32A ... collar, 32B ... pile part, 33 ... columnar member, 33A ... base, 33B ... adjustment part

Claims (6)

Between the upper surface portion and the lower surface portion facing each other, an air column is provided as an air layer, and an opening connected to the air layer is provided in the upper surface portion.
It said upper surface portion with respect to the chamber boundaries of the sound field is placed facing a space between the chamber boundary and the upper surface portion, the sound absorbing structure in which the space is in communication with the sound field. The sound absorbing structure according to claim 1, wherein the upper surface portion has a plate shape. A plurality of the air layers;
The upper surface portion is provided with an opening connected to the air layer for each air layer,
The position of the opening in the upper surface is different for each air layer.
The sound absorbing structure according to claim 1 or 2, wherein The sound absorbing structure according to claim 1, wherein a plurality of concave portions and a plurality of convex portions are provided on a side opposite to the chamber boundary side as viewed from the chamber boundary . The sound absorbing structure according to claim 4 , wherein a porous layer made of a porous material is provided in the recess. The sound absorbing structure according to claim 4 , wherein the opening of the recess is closed by a plate-like or film-like vibrating member that is deformed by an external force.

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