JPH08338082A - Sound-absorptive body and unit - Google Patents

Abstract

PURPOSE: To obtain a sound-absorptive body excellent in the sound-absorptive characteristic in the low frequency zone, by providing a plurality of ribs fixed so as to form resonant spaces connected to an air chamber, in the sound- absorptive body, and a plurality of pierced holes connected to the air chamber at the base bottom of the ribs. CONSTITUTION: A sound-absorptive structure is constituted of a wall face 1 and a sound-absorptive body 3 arranged through an air chamber 2, and a spacer 4. The sound-absorptive body is provided with a plurality of ribs 6 forming resonant spaces 5 connected to the air chamber 2, and a plurality of pierced holes 8 at the base bottom 7 positioned in the depth of the ribs 6. Sound waves from the outside collide with the sound-absorptive body on the surface and enter into the air chamber 2 and the resonant spaces 5 at the rear side through the pierced holes 8 and the waves are absorbed by the resonance effect of the air chamber 2 and the resonant spaces 5. Since the sound-absorptive body 3 has a structure provided with a number of pierced holes 8, a sound-absorptive structure excellent in the sound-absorptive characteristic of the low frequency zone can be formed by the combination with the air chamber 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorber suitable for being placed on the surface of a sound absorbing structure in applications such as acoustic design for indoor ceilings and wall surfaces, soundproof walls for outdoor noise prevention, and tunnel interiors. And a sound absorbing unit using the sound absorbing body.

[0002]

2. Description of the Related Art Conventionally, a fiber mat plate made of rock wool, glass wool or the like has been used as a sound absorbing plate provided on a ceiling or a wall surface. However, although these fiber mat plates have a sound absorbing effect in the mid-high range, they have a drawback that they have poor sound absorbing characteristics in the low frequency range. Therefore, as a sound absorbing structure having excellent sound absorbing characteristics in a low frequency range, there is known a sound absorbing plate having a perforated structure in which a plurality of through holes are provided in a flat plate in front of the air chamber.

[0003]

However, since the conventional sound absorbing plate having a perforated structure has a shape in which a large number of holes are opened in a plane, when it is arranged on the surface of a ceiling or a wall surface, it is opened in a plane. There was a problem that a large number of holes could be seen, and the viewpoint could not be fitted to the wall surface, causing flickering and discomfort. Further, since it has a simple shape in which a large number of holes are opened in a plane, there is a limit in design. Further, there is a problem that a large number of holes are contaminated and the appearance is deteriorated, or sound absorption characteristics are deteriorated.

The present invention has been made in view of the above problems, and can be used in front of an air chamber to form a sound absorbing structure having a good sound absorbing characteristic, and gives a good appearance. It is an object of the present invention to provide a sound absorbing body having a perforated structure that can be used.

Another object of the present invention is to provide a sound absorbing unit using the sound absorbing body.

[0006]

The invention according to claim 1 of the present application is as follows.
In order to solve the above-mentioned problems, a structure of a sound absorbing body, which is arranged in front of an air chamber and constitutes a sound absorbing structure together with the air chamber, communicates with the air chamber so as to project to the side opposite to the air chamber. A plurality of ribs provided so as to form a resonance space and a base portion formed between the ribs are provided, and a plurality of ribs communicating with the air chamber are provided on at least one of a side surface and a base portion of the rib. It is characterized in that a through hole is formed.

According to a second aspect of the present invention, in the above sound absorbing body, a sound absorbing material is further arranged on at least one of the inner surface and the outer surface of the base portion between the ribs.

Further, the invention of claim 3 has a construction in which a partition wall for dividing an air chamber behind is provided on the back surface of at least one of the rib and the base of the sound absorbing body.

Further, the invention according to claim 4 of the present invention is characterized in that the rib provided on the sound absorbing body has a portion having a cross-sectional shape that widens toward the tip.

According to a fifth aspect of the present invention, the size of the plurality of ribs provided on the sound absorbing body is two or more, and the volume of the resonance space formed by each rib is at least two.

According to a sixth aspect of the present invention, the sound absorber and the back plate are arranged with a space therebetween so as to form an air chamber behind the sound absorber, and the sound absorber and the back plate are integrated into a unit. It is a thing.

[0012]

According to the sound absorbing body of the invention of claim 1, when the sound absorbing body is attached to the front surface of the air chamber to form the sound absorbing structure, a plurality of ribs are on the front surface, so that the ribs have an appearance in which a large number of ribs are arranged side by side. Since it is formed on the side surface of the rib or on the base portion between the ribs, it is not very noticeable, and therefore, there is no flicker due to the through hole and no discomfort is given. In addition, since the sound absorber has a perforated structure with many through holes, it can form a sound absorbing structure with good sound absorbing characteristics in the low frequency range by combining with the air chamber, and at that time, the space inside the rib is a resonance space. The sound absorbing structure has a good sound absorbing property, and the sound absorbing structure can be made thinner than in the case of using a conventional porous plate. Further, various appearances can be given and various designs can be obtained by appropriately changing the intervals and widths of the ribs. In addition, the plurality of ribs also serve as a reinforcement, and the strength of the sound absorbing body can be improved.

According to the second aspect of the present invention, the sound absorbing body is further provided with a sound absorbing material on at least one of the inner surface and the outer surface of the base portion between the ribs, whereby the resonance frequency range can be expanded. Sound absorption characteristics in a wide frequency range can be improved.

According to a third aspect of the present invention, a partition wall is provided on the back surface of at least one of the rib and the base of the sound absorbing body to divide a space inside the rib and an air chamber behind the rib. A plurality of independent small chambers can be formed, and a resonance frequency corresponding to the independent small chambers can be realized. In other words,
By designing the volume of the independent small chamber to a value corresponding to the desired resonance frequency, it is possible to easily design a sound absorbing structure having desired sound absorbing characteristics.

Further, in the invention of claim 4 of the present application, since the rib provided on the sound absorbing body has a portion having a cross-sectional shape that widens toward the tip, the rib is formed on the base portion or the rib side surface. The effect of hiding the through hole is large, the appearance is improved, and the effect of preventing dust and dirt from adhering to the through hole can be prevented, and clogging of the through hole can be prevented for a long period of time.

According to a fifth aspect of the present invention, the size of the plurality of ribs provided on the sound absorbing body is two or more, and the volume of the resonance space formed by each rib is at least two. It is possible to set a plurality of frequencies, and it is possible to improve sound absorption characteristics in a wide frequency range.

According to a sixth aspect of the present invention, the sound absorber described above and the back plate are arranged so as to form an air chamber behind the sound absorber, and the sound absorber and the back plate are integrated into a unit. Thus, by simply arranging the sound absorbing units, a wall surface having a predetermined sound absorbing characteristic can be formed, and the sound absorbing structure can be easily manufactured on the construction site.

[0018]

The preferred embodiments of the present invention will be described below. FIG. 1 is a schematic perspective view of a sound absorbing structure constructed by using a sound absorbing body according to an embodiment of the present invention, FIG. 2 is a schematic sectional view of the sound absorbing structure, 1 is a wall surface, 2 is an air chamber, 3 is the air thereof. The sound absorbing body is attached to the wall surface 1 via the spacer 4 so as to be positioned in front of the chamber 2, and constitutes a sound absorbing structure together with the wall surface 1 and the air chamber 2. The sound absorber 3 is made of a plate material such as metal, plastic, or wood, and is provided so as to project to the side opposite to the air chamber 2 and form a resonance space 5 communicating with the air chamber 2. Multiple ribs 6,
The base portion 7 is formed between the ribs 6, and a plurality of through holes 8 communicating with the air chamber 2 are formed in the base portion 7.

In this sound absorbing structure, a sound wave from the outside hits the sound absorbing body 3 on the surface, passes through the through hole 8 and enters the air chamber 2 behind and the resonance space 5 in the rib 6, and the air chamber 2 and Sound is absorbed by the resonance effect of the resonance space 5.
At this time, as can be seen from the results of the sound absorbing experiments according to Examples to be described later, this sound absorbing structure has a characteristic that the sound absorbing effect is particularly high in the low frequency range. Further, by providing the resonance space 5 in the rib 6, the sound absorbing effect is high and the thickness of the sound absorbing structure can be remarkably reduced as compared with the conventional sound absorbing structure in which the porous plate is simply arranged in front of the air chamber. It also has the characteristic.

Here, the large number of through holes 8 formed in the sound absorbing body 3 are provided to facilitate the entry of sound into the air chamber 2, and the opening ratio, hole diameter, pitch, etc. are Room 2
It may be determined in consideration of the frequency characteristic of sound absorption due to the combination with the resonance space 5. Generally, the aperture ratio is preferably about 0.2 to 10%. Also, as the pore size,
It is preferably about 3 to 15 mm. The hole pitch may be appropriately set so as to match the above-described range of the aperture ratio and the hole diameter. Further, the width and height of the ribs 6 formed on the sound absorbing body 3 (hence, the volume of the resonance space 5 in the ribs 6) are also determined by the air chamber 2
It may be determined in consideration of the frequency characteristics of sound absorption due to the combination with the through holes 8. For example, the width of the widest portion of the rib 6 is about 40 to 100 mm, and the height is 50 to 1 mm.
It is preferably about 00 mm. The width of the plurality of ribs 6 provided on the sound absorbing body 3 may be constant or may be different. For example, the ribs 6 having two kinds of widths may be alternately arranged. Since the width of the rib 6 influences the sound absorption frequency, when a rib having a different width is used, a high sound absorption effect can be obtained in different frequency ranges. The same applies to the height of the rib 6. The thickness of the air chamber 2 formed behind the sound absorber 3 is also determined in consideration of the frequency characteristic of sound absorption,
For example, about 20 to 100 mm is preferable.

The sound absorbing body 3 is arranged on the front surface of the sound absorbing structure, so that the surface on the side having the ribs 6 can be seen. Therefore, the surface of the sound absorbing structure is in a state in which a plurality of ribs 6 are arranged side by side, and the through holes 8 formed in the base portion 7 located at the back of the groove 9 between the ribs 6 are hardly visible, and a large number of them are formed. Despite having the through hole 8, the through hole 8
There is no flicker due to the stripes, and the strip 6 has a striped side-by-side preferable appearance. Therefore, it is possible to give a good impression without giving discomfort to the viewer. Further, since the plurality of ribs 6 perform a reinforcing action, the ribs 6 have a larger strength than a flat plate-like perforated plate. Therefore, the sound absorber 3 is spaced apart from the wall 1 so as to form the air chamber 2. The support member (spacer 4 etc.) for attachment can be simplified. Further, since the through hole 8 is located deep in the groove 9, dirt and dust are prevented from adhering, and the through hole 8 can be prevented from being blocked for a long period of time.

In the above embodiment, the through hole 8 is formed at the center of the base portion 7 between the ribs 6, but the formation position of the through hole 8 is not limited to this position and can be appropriately changed. That is, the through hole 8 may be a position that communicates with the air chamber 2 or the resonance space 5 inside and is a position that is difficult to see from the outside. For example, as shown in FIG. It may be formed on a part or on the side surface of the rib 6 adjacent to the base portion 7 as shown in (b).

As described above, the rib 6 is provided to form the resonance space 5 to improve the sound absorption characteristics and to make the through hole 8 less visible, but the cross-sectional shape can be variously changed and the design can be changed. It may be designed in consideration of the above.
In the embodiment of FIG. 1, the rib 6 has a rectangular shape in which the tip end side is widened, and therefore the groove 9 between the ribs 6 has a shape in which the tip end side is narrowed, and the effect of hiding the through hole 8 of the base portion 7 is great. Have advantages. Other shapes include, for example, FIG.
Examples thereof include those shown in (a) to (g). In each of these figures, the lower side is the air chamber, and thus the upper side is the outer surface (front surface of the sound absorbing structure). FIG.
The sound absorbing body 3 shown in each of (a) to (g) has its rib 6
However, since it has a cross-sectional portion that widens toward the tip, it has a great effect of concealing the through hole (not shown in FIG. 4) formed in the base portion 7 or the rib side surface, and the appearance is improved and the penetration is improved. It also has the effect of preventing dust and dirt from adhering to the holes. Further, it is also possible to use a rib 6 having a simple cross-sectional shape as shown in FIGS. In this case, there is an advantage that the sound absorber 3 is easily manufactured.

The sound absorbing body 3 of the embodiment shown in FIG. 2 is composed of only a plurality of bristle 6 and a base portion 7 between the ribs 6, and upon mounting, it is mounted on the wall surface 1 via the spacer 4. It is attached. However, the sound absorbing body 3 of the present invention is not limited to this structure, and may have a structure in which mounting legs are integrally provided. FIG. 6 shows a sound absorbing body 3A in that case, which has a plurality of ribs 6 on the front surface and a base portion 7 between them, and has legs 11 at both ends thereof as a single plate structure.
In this sound absorbing body 3A, the air chambers 2 having a predetermined thickness can be formed between the sound absorbing body 3A and the wall surface 1 by attaching the sound absorbing body 3 to the wall surface 1 using the legs 11 at both ends.

FIG. 7 shows a sound absorbing unit 13 in which the sound absorbing body 3 and the air chamber of the present invention are unitized. That is, the sound absorbing unit 13 has a structure in which the sound absorbing body 3 arranged on the front surface and the back plate 14 arranged behind the sound absorbing body 3 so as to form the air chamber 2 are integrated.
As the sound absorber 3, the above-mentioned ones can be appropriately used. The sound absorbing unit 13 has an advantage that a sound absorbing wall having a constant sound absorbing characteristic can be easily formed by simply arranging the sound absorbing units 13.

In the sound absorbing body 3 of the embodiment described above, the air chamber 2 behind is one large space, but it is also possible to divide this into a plurality of small chambers. FIG. 8 shows an embodiment in that case. In the sound absorbing unit 13A shown in FIG. 8 (a), the sound absorbing body 3 arranged on the front surface has two types of ribs 6a and 6b having different widths alternately and at intervals. Different grooves 9a and 9b are arranged so as to sandwich a plurality of air chambers by providing a partition wall 15 on the back surface of one end of the base portion 7 and thus on an extension line of one side surface of the ribs 6a and 6b. Small room 2
It is divided into a and 2b. With this configuration, the air chamber is divided into a plurality of volumes of air chambers 2a and 2b, and one of the air chambers 2a absorbs sound of a certain frequency,
The other air chamber 2b absorbs a sound of a frequency different from that of the air chamber 2b, which has an advantage of expanding the sound absorption frequency range.
Further, in the sound absorbing unit 13B shown in FIG. 8B, the partition wall 15 is provided inside the ribs 6a and 6b. Also in this case, the same effect as that of FIG. In the embodiment shown in FIG. 8, the air chambers divided into a plurality have different volumes, but instead, the air chambers may be divided into the same volume. If the air chamber is divided into multiple small-volume chambers, the sound absorption characteristics for sound in a narrow frequency range that corresponds to the volume of the divided air chambers are improved, and therefore the frequency of the generated noise is limited to a narrow region. Is effective for.

In the sound absorbing units 13A and 13B shown in FIG.
Although the ribs 6a and 6b of the sound absorber 3 on the front surface are simply rectangular, the shape of the sound absorber 3 on the front surface is not limited to this.
Various shapes as shown in FIG. 5 can be used. That is, the partition wall 15 shown in FIG. 8 may be provided on the back surface of the sound absorber 3 shown in FIGS. 1 to 5 to divide the air chamber into a plurality of parts. Further, when such a partition wall 15 is provided, the back plate 14 does not necessarily have to be provided, and when the sound absorber 3 is attached to the wall surface 1 (see FIG. 1), the partition wall 15 hits the wall surface. The air chamber between the sound absorbing body 3 and the wall surface may be divided into a plurality of parts.

In the above embodiment, the rib 6 made of a plate material is used.
Although the sound absorbing body 3 including the base and the base portion 7 is shown, it is also possible to use a sound absorbing material in combination with the sound absorbing body 3. 9 (a), 9 (b), and 9 (c) show such an example. That is, in FIG. 9A, the plate-shaped sound absorbing material 17 is arranged on the inner surface (the surface on the air chamber side, that is, the back surface) of the sound absorbing body 3, and in FIG. 9B, the rib 6 of the sound absorbing body 3 is arranged. A sound absorbing material 18 is arranged on the outer surface of the base portion 7 between them. Also, FIG. 9 (c)
In, the cylindrical sound absorbing material 19 is arranged in the groove 9 formed between the ribs 6. Sound absorbing material 17, 1 used here
Reference numerals 8 and 19 are materials having a sound absorbing effect by themselves, and usually, porous materials such as glass wool, rock wool, fiber mat materials, and film materials such as canvas are used. When such a sound absorbing material is used together, the sound absorbing frequency range can be expanded.

[Examples] The following shows the results of measuring the sound absorption characteristics of various sound absorbing bodies according to the examples of the present invention.
The sound absorbing structure used is as shown in FIG.
The unit of dimensions shown in the drawing is mm. The sound absorbing body 3 is a sound absorbing body 3 with a sound absorbing material 17 added, and the sound absorbing body 3 with a thickness of an air chamber behind the sound absorbing body 3 is changed and sound absorbing materials 17 and 18 are added. Is. In the sound absorbers 3 shown in to, the through holes 8 having a diameter of 9 mm are formed in one row in the center of the base portion 7 with a pitch of 50 mm. Sound absorber 3
Is a sound absorber 3 with the addition of a sound absorbing material 18,
In the sound absorbing body 3 shown in FIG.
mm through holes 8 are formed in one row with a pitch of 100 mm. The sound absorbing body 3 is a sound absorbing body 3 with a sound absorbing material 18 added, and in the sound absorbing body 3 shown in, a through hole 8 having a diameter of 9 mm is pitched in the center of the base portion 7 on the bottom surface of the narrow groove 9a. A row of 50 mm is formed, and a through hole 8 having a diameter of 10 mm is formed at a pitch of 1 at the center of the base portion 7 on the bottom surface of the wider groove 9b.
One row is formed with 00 mm. Also, used sound absorbing material 1
7 and 18 are glass wool. The sound absorption coefficient was measured for each sound absorption structure shown in FIG. 10 to obtain the statistical incident sound absorption coefficient. Table 1 shows the results. The unit of the statistical incident sound absorption coefficient shown in Table 1 is%.

[Comparative Examples 1 to 3] As shown in FIG. 11, a perforated gypsum board 20 is arranged so as to form a 300 mm air chamber 2 in front of the wall surface 1 (Comparative Example 1) A rock wool sound absorbing felt 22 having a thickness of 25 mm is arranged on the back surface of a perforated gypsum board 20 (Comparative Example 2), and a perforated calcium silicate plate 23 is arranged in front of the wall surface 1 so as to form an air chamber 2 of 300 mm. Table 1 also shows the sound absorption results of the one having the 25 mm thick rock wool sound absorbing felt 22 arranged on the back surface thereof (Comparative Example 3).

[0031]

[Table 1]

The results of Table 1 are shown in the graphs of FIGS. As can be seen from Table 1 and the graphs of FIGS. 12 to 14, the examples have a relatively narrow frequency range, but have a region exhibiting a high sound absorption coefficient, and particularly the examples have a low frequency range of 125 to 160 Hz. There is a peak of sound absorption coefficient. Therefore, by appropriately designing the width of the rib 6 and the depth of the air chamber 2, it is possible to obtain a sound absorbing structure having a high sound absorbing coefficient in a desired low frequency range. Further, in the embodiment, there are peaks with high sound absorption coefficient in a plurality of frequency ranges. Therefore, it is suitable for applications requiring sound absorption in a plurality of frequency ranges. Furthermore, comparing the case where the sound absorbing material 17 or 18 is used together with the case where the sound absorbing material 17 is not used, the peak sound absorption rate does not change much, but the case where the sound absorbing materials 17 and 18 are used together (Examples,
,,,) have improved sound absorption over a wider frequency range. Therefore, when the frequency range of noise is wide,
It is preferable to use a sound absorbing material together. Also, comparing the results with the examples, the sound absorption characteristics of the examples are superior. Therefore, considering only the sound absorbing characteristics, it is preferable to arrange the sound absorbing material 18 on the outer surface of the sound absorbing body 3.

On the other hand, in Comparative Example 1, the sound absorbing effect is low as a whole and cannot be said to be effective. In Comparative Examples 2 and 3, the sound absorbing effect is considerably improved, but the effect is mainly exhibited at a frequency of 200 Hz or higher, and the effect is not so improved in a low frequency range of 160 Hz or lower. On the contrary,
In Examples 1 to 5 of the present invention, a considerable sound absorbing effect is exhibited in a low frequency range of 160 Hz or lower, and the thickness of the entire sound absorbing structure is 15 mm compared to 300 mm in Comparative Examples 1 to 3.
A thickness of 0 mm and half the thickness is sufficient, and it has a sufficient sound absorbing effect. This is considered to be an effect of the resonance space 5 formed in the rib 6.

[0034]

As described above, the sound absorbing body of the invention of claim 1 of the present application is provided so as to project to the side opposite to the air chamber and to form a resonance space communicating with the air chamber. By having a plurality of ribs and a base portion formed between the ribs, and having a plurality of through holes communicating with the air chamber on at least one of the side surface and the base portion of the rib, By combining with an air chamber, a sound absorbing structure with good sound absorbing characteristics in the low frequency range can be formed, and at that time the space inside the ribs acts as a resonance space, so the sound absorbing characteristics are good, and compared to the case of using a conventional perforated plate. It is possible to make the sound absorbing structure thin. For example, when the perforated plate is used,
It is possible to make it half, that is, 150 mm, with respect to 0 mm. Furthermore, the appearance is that a plurality of ribs are arranged on the front surface.
Since the through holes are almost inconspicuous, there is no flicker due to the through holes, so no discomfort is given, and by appropriately changing the interval or width of the ribs,
It has various effects such as giving various appearances, changing to various designs, and improving the strength of the sound absorber by the reinforcing effect of the ribs.

According to a second aspect of the present invention, by further disposing a sound absorbing material on at least one of the inner surface and the outer surface of the base between the ribs, the resonance frequency range can be expanded. It has the effect of improving the sound absorption characteristics in a wide frequency range.

The invention of claim 3 is independent by providing a partition wall on the back surface of at least one of the rib and the base of the sound absorbing body to divide the air chamber behind into a plurality of small chambers. By forming a plurality of small chambers and designing the volume of the independent small chambers to a value corresponding to the desired resonance frequency, it is possible to easily design a sound absorbing structure having a desired sound absorbing characteristic.

Further, in the invention of claim 4 of the present application, since the rib provided on the sound absorbing body has a portion having a cross-sectional shape that widens toward the tip, the rib is formed on the base portion or the rib side surface. The effect of concealing the through holes is large, the appearance is improved, and there is also the effect of preventing dust and dirt from adhering to the through holes, which has the effect of preventing clogging of the through holes for a long period of time. There is.

According to a fifth aspect of the present invention, the size of the plurality of ribs provided on the sound absorbing body is two or more, and the volume of the resonance space formed by each rib is at least two. There is an effect that a plurality of frequencies can be set and sound absorption characteristics in a wide frequency range can be improved. In particular, by using a sound absorbing material together with the sound absorbing body of this configuration, it is possible to improve sound absorbing characteristics in a wide frequency range,
The effect that noise in a wide frequency range can be absorbed is obtained.

According to a sixth aspect of the present invention, the sound absorber described above and the back plate are arranged at a distance so as to form an air chamber behind the sound absorber, and the sound absorber and the back plate are integrated into a unit. As a result, by simply arranging the sound absorbing units, a wall surface having a predetermined sound absorbing characteristic can be formed, and the sound absorbing structure can be easily manufactured at a construction site.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a sound absorbing structure configured by using a sound absorbing body according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of the sound absorbing structure.

3A and 3B are schematic cross-sectional views showing an embodiment in which a through hole is provided at a position different from the above embodiment.

4A to 4G are schematic cross-sectional views showing an embodiment of a sound absorber having different cross sections.

5 (a) and 5 (b) are schematic cross-sectional views each showing an embodiment of a sound absorbing body having a cross section different from that of the above-mentioned embodiment.

FIG. 6 is a schematic sectional view showing a sound absorbing body according to another embodiment.

FIG. 7 is a schematic sectional view of a sound absorbing unit according to an embodiment of the present invention.

8A and 8B are schematic cross-sectional views of a sound absorbing unit according to another embodiment of the present invention.

9A and 9B are schematic cross-sectional views showing a sound absorbing body according to another embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view showing a cross-sectional structure of Examples 1 to 5.

FIG. 11 is a schematic sectional view showing a sectional structure of Comparative Examples 1 to 3.

FIG. 12 is a graph showing sound absorption characteristics of Examples ,,,

FIG. 13 is a graph showing sound absorption characteristics of Examples ,,,

FIG. 14 is a graph showing sound absorption characteristics of the example.

[Explanation of symbols]

 1 Wall Surface 2 Air Chamber 2a, 2b Small Chamber 3 Sound Absorber 4 Spacer 5 Resonance Space 6, 6a, 6b Rib 7 Base 8 Through Holes 9, 9a, 9b Groove 11 Leg 13, 13A, 13B Sound Absorption Unit 14 Back Plate 15 Partition Wall 17, 18, 19 Sound absorbing material

Front Page Continuation (72) Inventor Tadanori Mizukami 3-17-11 Midoricho, Fuchu, Tokyo Dormy Higashi Fuchu 305 (72) Inventor Yutaka Tasaki 2-34-16 Nakazato, Ninomiya-cho, Naka-gun, Kanagawa Prefecture (72) Inventor San Kamitaka 1-41-2 Nakaarai, Tokorozawa, Saitama Nitto Spinning Co., Ltd. Nitto Dormitory

Claims (6)

[Claims] 1. A sound absorbing body which is arranged in front of an air chamber and constitutes a sound absorbing structure together with the air chamber, wherein a resonance space which projects to a side opposite to the air chamber and communicates with the air chamber. It has a plurality of ribs provided so as to form, and a base portion formed between the ribs, and has a plurality of through holes communicating with the air chamber on at least one of the side surface and the base portion of the rib. A sound absorbing body characterized by that. 2. The sound absorbing body according to claim 1, further comprising a sound absorbing material disposed on at least one of an inner surface and an outer surface of a base portion between the ribs. 3. The sound absorbing body according to claim 1, further comprising a partition wall that divides an air chamber behind the rib on at least one of the back surface of the rib and the base portion. 4. The rib according to claim 1, wherein the rib has a portion having a cross-sectional shape that widens toward the tip.
The sound absorber according to any one of 1. 5. The resonance space formed by the plurality of ribs has at least two types of volumes.
5. The sound absorbing body according to any one of items 4 to 4. 6. A sound absorbing body according to any one of claims 1 to 5 and a back plate, which is arranged at a distance so as to form an air chamber behind the sound absorbing body, as an integral structure. Sound absorption unit.