JP2001108289A - Ventilation-type sound insulating wall structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To see that columnar resonance does not occur within a duct provided with ventilation-type sound insulating wall structure such as a ventilation duct or the like by the noise wave having collided against the wall face of the ventilation-type sound insulating wall structure. SOLUTION: A shell assembly 1 is constituted by counterposing a pair of shells 2 and 3 thereby forming an air layer 4 between these shells 2 and 3. Both shells 2 and 3 are provided with holes 5 and 5 located opposite to each other, respectively, and a pair of short pipes 6 and 6 are provided in communication with the holes 5 and 5 in an opposed relation with a space at the inwall faces of the shells 2 and 3, thus a ventilation part 7 to connect the inside and the outside of the air layer 4 with each other is made between the short pipes 6 and 6. Both ends of a long pipe 8 arranged apart from the short pipes 6 and 6 are provided, respectively, at each wall face of the shells 2 and 3, and through holes 9 leading to the long pipe 8 are made in the shells 2 and 3. Furthermore, a noise wave reflecting face 31 comprising a sound absorbing wall layer 30 is made at the outer wall of the shell 2, and this reflecting face 31 prevents the resonance of air column caused by the noise sound colliding against the outer wall of the shell 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ventilation duct for absorbing and attenuating noise energy, for example, for use as an outside air introduction duct in a residence room or a sound insulation cover of a ventilation duct in a soundproof room such as a motor or a pump (hydraulic pump, etc.). The present invention relates to a type sound insulation wall structure.

[0002]

2. Description of the Related Art Conventionally, in order to cut off sound generated outside or inside a room through a room or outside air, for example, in an outside air introduction duct of a residence room or a ventilation duct of a soundproof room provided with a motor or a pump. JP-A-11-
It is known to use the sound absorbing duct disclosed in Japanese Patent No. 117761.

[0003] According to this, a sound absorbing material having a random waveform is attached to the inner wall of the duct to secure a central portion of the duct as an air passage. Are made to interfere with each other at a portion where the cross-sectional shape changes, thereby trying to absorb sound.

However, according to such a configuration, even if noise abutting on the sound absorbing material attached to the inner wall of the duct is absorbed, the noise enters through the inlet side of the duct and impinges on the central air passage against the sound absorbing material. The noise wave that has passed without touching it will be propagated to the exit side as it is.

Therefore, as a ventilated sound insulation structure intended to reduce noise passing through the air passage of the duct, one disclosed in Japanese Patent Application Laid-Open No. Hei 7-175485 is known.

According to this, for example, as shown in FIG.
Soundproof room R with noise source N such as motor and pump installed
When a ventilation duct V is provided to ventilate the interior of the soundproof room R, a ventilation type sound insulation wall structure P is fitted to the ventilation duct V.

[0007] As shown in FIGS. 7 and 8, the ventilation type sound insulation wall structure P has an upper shell 2 and a lower shell 3 opposed to each other, and air is provided between the upper and lower shells 2 and 3. The shell assembly 1 is formed by forming the layer 4, and holes 5 are provided on the wall surfaces of the upper and lower shells 2 and 3, respectively, and the short pipes communicate with the holes 5 and face each other with a gap therebetween. 6,
6 are respectively formed, and a ventilation part 7 is formed between the short pipe parts 6 and 6, and both ends of one or more long pipe parts 8 which are arranged apart from the short pipe parts 6 and 6 are respectively moved up and down. It stands on each wall surface of both shells 2 and 3, and is formed by forming a through hole 9 in the long tube portion 8, and the inside and outside of the soundproof room R are communicated by the short tube portions 6, 6 and the long tube portion 8, It allows air to flow.

[0008] With such a short tube portion 6 and a long tube portion 8,
The transmitted wave A from the long tube portion 8 is transmitted as it is by the incident wave X coming from the noise source N, whereas the transmitted wave B from the short tube portion 6 is air formed between the short tube portions 6. Above the resonance point of the two free vibration system of the layer 7, the transmitted wave A is transmitted as a wave B having an opposite phase to the transmitted wave A. For this reason, the whole transmitted wave, which is the sum of the transmitted wave A and the transmitted wave B, is attenuated by the interference result, and as a result, exhibits a sound insulation effect. From the outside.

[0009]

However, in the ventilated sound insulation wall structure P constructed as described above, the incident waves X other than the transmitted waves A and B passing through the short tube portion 6 and the long tube portion 8 are transmitted to the panel. It collides with the side wall 1a on the soundproof room R side of the assembly 1 and becomes a reflected wave X ', returning to the soundproof room R direction on the same line as the incident direction line of the incident wave X.

As a result, by vibrating the air in the ventilation duct V on the current noise N side, the soundproof room R on the sound source side is vibrated.
When the sound pressure on the side increases and the air column resonance as shown by the two-dot chain line in FIG. 6 occurs and reaches the resonance frequency, the resonance sound with the increased sound pressure is emitted to the outside through the ventilation duct V. As a result, the sound insulation performance of the ventilation type sound insulation wall structure P is deteriorated.

Therefore, the present invention has been made in view of the above points,
An object of the present invention is to provide a ventilation type sound insulation wall structure in which air column resonance does not occur in a duct provided with a ventilation type sound insulation wall structure such as a ventilation duct due to a noise wave abutting on a wall surface of the ventilation type sound insulation wall structure.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a shell assembly comprising a duct, at least two shells facing each other, and an air layer formed between the two shells. And the shells are provided with holes facing each other, and a pair of short pipes are provided on the inner wall surface of each shell so as to communicate with the holes and to face each other with a gap therebetween. Forming a ventilation portion between the short tube portions to communicate the inside and outside of the air layer, and providing both ends of a long tube portion arranged apart from the short tube portion on each inner wall surface of each of the shells. In the ventilated sound insulation structure in which through-holes communicating with the long pipe portions are formed in both the shells, a reflection surface of the noise wave formed of a sound absorbing wall layer is formed on an outer wall surface of at least one of the two shells. It is composed. The present invention also provides a shell assembly which is installed in a duct, has at least two shells opposed to each other, forms an air layer between the two shells, and has a hole formed in the shells facing each other. And a long tube portion is provided in each of the shells so as to communicate with the two hole portions and to oppose each other with a gap therebetween, and to communicate the inside and outside of the air layer with the long tube portion. In the ventilation type sound insulation structure formed by forming a ventilation portion, a reflection surface of a noise wave formed of a sound absorbing wall layer is formed on an outer wall surface of at least one of the two shells.

According to the present invention, the reflection surface on the outer wall surface side of one shell is installed toward the noise source side, so that the noise wave on the noise source side abuts on the outer wall surface of one shell. However, this noise wave is converted into kinetic energy by minutely vibrating the air in the sound absorbing wall layer forming the reflecting surface, or the vibration of the air in the sound absorbing wall layer forming the reflecting surface is changed inside the sound absorbing wall layer. In this case, a sound absorption effect is exhibited, air column resonance can be prevented, and an increase in sound pressure on the sound source side can be suppressed.

According to the present invention, a shell assembly is formed by installing at least two shells in a duct and forming an air layer between the two shells, and the shells are opposed to each other. A pair of short pipes are provided on the inner wall surfaces of the shells so as to communicate with the holes and face each other with a gap therebetween, and the air layer is formed between the short pipes. A ventilation portion for communicating the inside and the outside is formed, and both ends of a long tube portion which is disposed apart from the short tube portion are provided on each inner wall surface of the both shells, and the both shells communicate with the long tube portion. In the pass-through type sound insulation structure in which the through holes are formed, a reflection surface is formed on the outer wall surface of at least one of the two shells so that the noise wave is reflected along a direction line different from the incident direction line. Make up. The present invention also provides a shell assembly which is installed in a duct, has at least two shells opposed to each other, forms an air layer between the two shells, and has a hole formed in the shells facing each other. And a long tube portion is provided in each of the shells so as to communicate with the two hole portions and to oppose each other with a gap therebetween, and to communicate the inside and outside of the air layer with the long tube portion. In the ventilation type sound insulation structure configured by forming a ventilation portion, of the two shells,
At least one of the shells has a configuration in which a reflection surface is formed on an outer wall surface of the shell to reflect a noise wave along a direction line different from the incident direction line.

[0015] The reflecting surface may be formed, for example, by inclining the outer wall surface of the one shell with respect to the axis of the short tube portion and the long tube portion, or may have an uneven surface such as a curved surface.
It is formed in a wave-shaped sawtooth shape.

According to the present invention, by setting the reflection surface of the outer wall surface of one shell toward the noise source side, the noise wave of the noise source side abuts on the outer wall surface of one shell. Also, since the outer wall of one shell has a reflecting surface that reflects noise waves along a direction line different from the incident direction line, the occurrence of air column resonance in a duct with a ventilation type sound insulation wall structure is prevented It is possible to suppress an increase in sound pressure on the sound source side.

[0017]

Embodiments of the present invention will be described below.

FIG. 1 shows a first embodiment of the present invention, and is a longitudinal sectional view when the apparatus is installed in a duct.

According to FIG. 1, a duct 12 communicating with the inside and outside of the soundproof room R for ventilation is provided in a soundproof room R provided with a noise source (not shown) such as a motor and a hydraulic pump.
In the duct 12, a ventilation type sound insulation wall structure 20 is installed so as to cross the passage space 12a.

As shown in FIG. 6, the ventilated sound insulation wall structure comprises a pair of shells 2 and 3 opposed to each other, and an air layer 4 is formed between the shells 2 and 3 to form a shell assembly. 1 and a plurality of holes 5 facing each wall surface of both shells 2 and 3 are provided, and short tube portions 6 and 6 communicating with the holes 5 and facing each other with a gap therebetween are formed. Thus, a ventilation section 7 is formed between the short pipe sections 6 and 6, and both ends of one or more long pipe sections 8 disposed apart from the short pipe sections 6 and 6 are respectively formed on both shells 2 and 3. Standing on each wall surface, a through hole 9 is formed in the long tube portion 8, and the inside and outside of the soundproof room R are communicated by the short tube portions 6, 6 and the long tube portion 8 so that air can be circulated. I have.

Then, as shown in FIG. 8, the transmitted wave A from the long tube portion 8 is transmitted by the short tube portion 6 and the long tube portion 8 by the incident wave X coming from the noise source. On the other hand, the transmitted wave B from the short tube portion 6 is opposite to the transmitted wave A at the resonance point of the two free vibration systems of the air layer 7 formed between the short tube portions 6. B is transmitted. Therefore, the entire transmitted wave, which is the sum of the transmitted wave A and the transmitted wave B, is attenuated by the result of the interference, and as a result, exhibits a sound insulation effect. It does not propagate outside.

Further, in the first embodiment, of the pair of panels 2 and 3, the sound absorbing wall layer 30 is attached to the outer wall surface 2a of the panel 2 facing the soundproof room R side, thereby reducing noise. A reflection surface 31 for noise waves from the source is formed.

The sound absorbing wall layer 30 is provided with a communication hole 30 a corresponding to the hole 5 and the through hole 9. Also, the sound absorbing wall layer 3
0 is a film material such as canvas or tent cloth, a porous material such as glass wool, cotton, sponge, etc .; a porous molding material such as rock wool molded sound absorbing plate, glass wool molded sound absorbing plate; And the like.

Therefore, in the ventilation type sound insulation wall structure 20,
The noise waves S other than the transmitted waves A and B passing through the short tube portion 6 and the long tube portion 8 abut against the reflection surface 31, but since the reflection surface 31 is constituted by the sound absorbing wall layer 30, the sound absorption is performed. The air existing in the air chamber inside the wall layer 30 is converted into kinetic energy by vibrating the air minutely, or the vibration of the air in the sound absorbing wall layer 30 causes diffusion in bubbles inside the sound absorbing wall layer 30. By doing so, a sound absorbing effect is exhibited, and the occurrence of air column resonance is prevented.

As a result, the noise from the noise source installed in the soundproof room R is cut off or reduced, and
2 to the outside.

2 to 5 show another embodiment of the present invention.

According to the second embodiment shown in FIG. 2, both panels 2 and 3 of the ventilation type sound insulation wall structure 20 are inclined at a predetermined angle with respect to the incident line of the noise to be sound-insulated, that is, the axial line of the duct 12. The side of the panel 2 facing the soundproof room R is a noise reflection surface 31.

As a result of this configuration, the outer wall surface 2a of the shell 2 is installed facing the noise source side,
Even though the noise wave S on the noise source side abuts and reflects on the outer wall surface 2a, since the outer wall surface 2a is formed on a slope,
The noise wave S is refracted in a direction different from the incident direction line of the noise wave without returning in the opposite direction on the same line with respect to the incident direction, and the air in the duct 12 in which the ventilation type sound insulating wall structure 20 is installed is formed. , The sound pressure on the noise source side does not increase. As a result, the occurrence of air column resonance can be prevented, and the increase in the sound pressure on the sound source side can be suppressed.

As a result, the noise from the noise source installed in the soundproof room R is cut off or reduced, and
2 to the outside.

According to the third embodiment of the present invention shown in FIG. 3, the reflecting surface 31 is formed on an uneven surface, for example, a corrugated surface, and the noise wave S does not return on the same line in the incident direction. The sound wave is refracted by irregular reflection in a direction different from the incident direction line of the noise wave, and by suppressing the vibration of the air in the duct 12 in which the ventilation type sound insulation wall structure 20 is installed, the sound pressure on the noise source side is not increased. In addition, the occurrence of air column resonance is prevented.

As a result, the noise from the noise source installed in the soundproof room R is cut off or reduced, and
2 to the outside.

According to the fourth embodiment of the present invention shown in FIG. 4, the reflecting surface 31 is formed in an uneven surface, for example, a sawtooth surface, and the noise wave S does not return on the same line in the incident direction. The sound wave is refracted by irregular reflection in a direction different from the incident direction line of the noise wave, and by suppressing the vibration of the air in the duct 12 in which the ventilation type sound insulation wall structure 20 is installed, the sound pressure on the noise source side is not increased. In addition, the occurrence of air column resonance can be prevented, and an increase in sound pressure on the sound source side can be suppressed.

As a result, the noise from the noise source installed in the soundproof room R is blocked or reduced, and
2 to the outside.

According to the fifth embodiment of the present invention shown in FIG. 5, the ventilated sound insulation wall structure 20 is different from the above-described embodiment in that the short tube portion 6 is eliminated and the hole portions 5 opposed to each other are formed in the shells 2 and 3. Are provided in both shells 2 and 3 so as to communicate with both holes 5 and to face both shells 2 and 3 with a gap therebetween.
A ventilation portion 40 for communicating the inside and outside of the shell 2 is formed, and a reflection surface of the noise wave formed of the sound absorbing wall layer 30 is formed on the outer wall surface of the shells 2, 3, for example, on the outer wall surface of the shell 2.

The long tube portion 8 has a butt portion 41 divided at a substantially central portion, and a communication portion 40 is formed by forming a substantially circular communication hole in the butt portion 41.

According to the fifth embodiment of the present invention shown in FIG. 5, the frequency characteristics are adjusted by changing the number, shape, size, and the like of the ventilation portions 40 provided in the butting portion 41.
The frequency at which the maximum value of the sound insulation performance is obtained is matched with the frequency of the sound intended for sound insulation.

Therefore, according to the fifth embodiment, it is natural that the reflection surface 31 as shown in the second to fourth embodiments can be used instead of the sound absorbing wall layer 30.

According to the above-described embodiment, the reflection surface 31 is provided on the outer wall surface of the panel 2 facing the soundproof room R side to reduce noise generated from the noise source on the soundproof room R side. The noise is transmitted to the outside of the soundproof room R. However, the present invention is not limited to this. For example, when used in an outside air introduction duct provided in a living room of a house, noise transmitted from the outside of the living room to the living room is used. Is required to be reduced, so that it is provided on the outer wall surface of the panel 3 facing the outside of the room. Further, when the indoor and outdoor noises are mutually reduced,
The reflection surface 31 is provided on the outer wall surfaces of both panels 2 and 3.

[0039]

As described above, according to the present invention, at least one of the shells has a reflection surface formed of a sound absorbing layer or an uneven surface formed on the outer wall surface thereof. By doing so, even if the noise wave of the noise source side abuts on the outer wall surface of one of the shells, the noise wave is absorbed by the reflection surface or along the direction line different from the incident direction line of the noise wave. By reflecting, it is possible to suppress the vibration of air in the duct where the ventilation type sound insulation wall structure is installed, and as a result, it is possible to prevent air column resonance from occurring without increasing the sound pressure on the sound source side, Will be transmitted through the duct to the opposite side of the noise source.

[Brief description of the drawings]

FIG. 1 shows Embodiment 1 of the present invention, and is a longitudinal sectional view when installed in a duct.

FIG. 2 shows a second embodiment of the present invention, and is a longitudinal cross-sectional view when installed in a duct.

FIG. 3 shows a third embodiment of the present invention, and is a longitudinal cross-sectional view when installed in a duct.

FIG. 4 shows a fourth embodiment of the present invention, and is a longitudinal sectional view in a case where it is installed in a duct.

FIG. 5 is a perspective view showing a cross section of a part of a ventilation type sound insulation structure according to a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional plan view of a soundproof room in which a ventilation type sound insulating wall structure is installed in an outside air introduction duct.

FIG. 7 is a perspective view showing a cross section of a part of a conventional ventilation type sound insulation wall structure.

FIG. 8 is an explanatory diagram of a sound insulation mechanism of a ventilation type sound insulation wall structure.

[Explanation of symbols]

 N Noise source R Soundproof room V Ventilation duct 1 Shell assembly 2, 3 Shell 2a Outer wall surface 4 Air layer 5 Hole 6 Short pipe 7 Ventilation section 8 Long pipe section 9 Through hole 12 Duct 12a Passage space 20 Ventilation type sound insulation wall structure Reference Signs List 30 sound absorption wall layer 30a communication hole 31 reflection surface 40 communication part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3L080 AE02 5D061 BB02 BB07 BB18 BB37 CC07 DD07 EE01 EE03 EE04 EE21 EE24 EE27 EE34

Claims (6)

[Claims] At least two shells are installed in a duct and opposed to each other. An air layer is formed between the two shells to form a shell assembly. A pair of short pipes are provided on the inner wall surface of each of the shells so as to communicate with the holes and to face each other with a gap therebetween, so that the inside and outside of the air layer communicate with each other between the short pipes. A ventilation portion is formed, and both ends of a long tube portion arranged apart from the short tube portion are provided on each inner wall surface of both shells, and a through hole communicating with the long tube portion is provided in both shells. In the ventilated sound insulation structure formed as described above, at least one of the two shells is provided with a noise wave reflection surface formed of a sound absorbing wall layer on an outer wall surface thereof. 2. At least two shells installed in a duct are opposed to each other, an air layer is formed between the two shells to form a shell assembly, and holes facing each other are formed in the shells. A pair of short pipes are provided on the inner wall surface of each of the shells so as to communicate with the holes and to face each other with a gap therebetween, so that the inside and outside of the air layer communicate with each other between the short pipes. A ventilation portion is formed, and both ends of a long tube portion arranged apart from the short tube portion are provided on each inner wall surface of both shells, and a through hole communicating with the long tube portion is provided in both shells. In the pass-through type sound insulation structure formed respectively, a reflection surface is formed on an outer wall surface of at least one of the two shells to reflect a noise wave along a direction line different from the incident direction line. Ventilated sound insulation wall structure. 3. A shell assembly which is installed in a duct, has at least two shells opposed to each other, and forms an air layer between the two shells to form a shell assembly. A long tube portion is provided in each of the shells so as to communicate with the two hole portions and to oppose each other with a gap therebetween, and a ventilation for communicating the inside and outside of the air layer with the long tube portion. In a ventilated sound insulation structure formed by forming a portion, a reflection surface of a noise wave composed of a sound absorbing wall layer is formed on an outer wall surface of at least one of the two shells. 4. A shell assembly which is provided in a duct, has at least two shells opposed to each other, and forms an air layer between the two shells to form a shell assembly. A long tube portion is provided in each of the shells so as to communicate with the two hole portions and to oppose each other with a gap therebetween, and a ventilation for communicating the inside and outside of the air layer with the long tube portion. In the ventilated sound insulation structure formed by forming a portion, a reflection surface is formed on an outer wall surface of at least one of the two shells to reflect a noise wave along a direction line different from the incident direction line. The ventilation type sound insulation wall structure characterized by the above. 5. The ventilation type sound insulation wall according to claim 2, wherein the reflection surface is formed by inclining an outer wall surface of the one shell with respect to an axis of the long tube portion. Construction. 6. The ventilation type sound insulation wall structure according to claim 2, wherein the reflection surface is formed by forming an outer wall surface of the at least one shell into an uneven surface.