Sheet-like soundproof structure

Abstract

The present invention comprises an elastic sheet and a support member that supports the sheet by being connected to the main surface of the sheet. The support member includes a plurality of openings arranged to face the sheet. The sheet includes: a connection portion connected to the support member and having a shape following the support member connection surface that is connected to the sheet; and a partition portion facing the openings and surrounded by the connection portion. The partition portion is deformed such that the central portion of the partition portion is displaced, with respect to the connection portion, in the thickness direction of the partition portion.

Description

Sheet-type soundproof structure

[0001] The present invention relates to a sheet-like soundproof structure.

[0002] WO2019 / 022245A discloses a sheet-like soundproof structure including an elastic sheet and a support member that supports the sheet and divides the sheet into compartments.

[0003] However, in the structure of WO2019 / 022245A, the frequency band that effectively blocks sound waves is fixed by the surface rigidity and surface density of the partition, making it difficult to set it according to the frequency band of the sound waves to be soundproofed.

[0004] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet-like soundproof structure capable of setting a cutoff frequency band according to the frequency band of sound waves to be soundproofed.

[0005] According to one aspect of the present invention, a device includes an elastic sheet and a support member that supports the sheet by connecting to a main surface of the sheet, the support member having a plurality of openings arranged to face the sheet, the sheet including a connecting portion that is connected to the support member and has a shape that matches the connecting surface of the support member that connects to the sheet, and a partition portion that faces the opening and is surrounded by the connecting portion, and the partition portion is deformed such that a center portion of the partition portion is displaced in the thickness direction of the partition portion relative to the connecting portion.

[0006] FIG. 1 is a top view of a sheet-like soundproof structure of this embodiment. FIG. 2 is a bottom view of the sheet-like soundproof structure of this embodiment. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 1. FIG. 4A is a diagram showing the state before a sheet is sandwiched in a mold having a cavity for forming a support member in the manufacturing process of the sheet-like soundproof structure of this embodiment. FIG. 4B is a diagram showing the state after the sheet is sandwiched in the mold in the manufacturing process of the sheet-like soundproof structure of this embodiment. FIG. 4C is a diagram showing the state after molten metal containing the material of the support member is injected into the mold (cavity) in the manufacturing process of the sheet-like soundproof structure of this embodiment. FIG. 4D is a diagram showing the state after the molten metal has solidified in the manufacturing process of the sheet-like soundproof structure of this embodiment and the sheet-like soundproof structure has been removed from the mold. FIG. 5 is a model of a sheet-like soundproof structure for representing the transmission loss of sound waves input into the sheet-like soundproof structure. FIG. 6 shows the relationship between sound wave loss and road noise band for the model of FIG. 5 before the surface rigidity is set high, and the relationship between sound wave loss and road noise band for the model of FIG. 5 after the surface rigidity is set high. FIG. 7 shows a comparison between the insertion loss of a sheet-like soundproof structure of a comparative example in which the partitions are flat and the insertion loss of the sheet-like soundproof structure of this embodiment in which the partitions are convex. FIG. 7 shows a vibration model (vibration mode) of peak loss for the sheet-like soundproof structure of this embodiment. FIG. 9 shows the relationship between the ratio of the depth of the partitions to the long side of the partitions and the frequency of peak loss. FIG. 10A shows a state in which a sheet is sandwiched in a mold having a cavity for forming a support member in a manufacturing process for a sheet-like soundproof structure of a modified embodiment of this embodiment. FIG. 10B shows a state in which molten metal containing the material for the support member is injected into the mold (cavity) in a manufacturing process for a sheet-like soundproof structure of a modified embodiment of this embodiment. FIG. 10C shows a state in which the sheet-like soundproof structure is removed from the mold after the molten metal has solidified in a manufacturing process for a sheet-like soundproof structure of a modified embodiment of this embodiment. 11 and 12 are cross-sectional views of a first and second modified partitioning portion of the present embodiment, respectively.

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] [Basic Configuration of Sheet-Like Soundproof Structure 1] Fig. 1 is a top view of the sheet-like soundproof structure 1 of this embodiment. Fig. 2 is a bottom view of the sheet-like soundproof structure 1 of this embodiment. Fig. 3 is a cross-sectional view taken along line A-A in Fig. 1.

[0009] The sheet-like soundproofing structure 1 of this embodiment includes a rectangular elastic sheet 2 and a support member 3 that supports the sheet 2 and divides the sheet 2 into a planar shape. "Elastic" means that the Young's modulus is a value within the range of 0.001 to 70 GPa and that the sheet is flexible. The sheet-like soundproofing structure 1 of this embodiment is attached, for example, inside a vehicle to reduce road noise from the road surface while the vehicle is traveling.

[0010] The support member 3 is a member that supports the sheet 2 by connecting (joining) it to the main surface of the sheet 2. The support member 3 has a lattice shape in which crosspieces 32 are constructed to form a plurality of polygonal openings 31 that are arranged to face the sheet 2. As shown in Figures 1 and 2, the support member 3 has a honeycomb shape in which hexagonal openings 31 are arranged, but any shape that can form a lattice shape, such as a circle, a triangle, or a rectangle, can be used. Furthermore, the lattice shape does not need to be uniform, and may be a lattice shape that combines two or more polygons with different numbers of corners.

[0011] The support member 3 is made of resin, but any resin that can be used for injection molding, which will be described later, can be used. Examples of materials that can be used for injection molding include polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM), polyphthalamide (PPA), polypropylene (PP), and polybutylene terephthalate (PBT).

[0012] The sheet 2 is a flat film-like member made of rubber, including synthetic rubber, such as natural rubber, chloroprene rubber (CR), styrene-butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), and the like.

[0013] The sheet 2 includes a connection portion 21 that is connected to the support member 3 and has a shape that conforms to the connection surface of the support member 3 (crosspiece portion 32) that connects to the sheet 2, and a partition portion 22 that faces the opening 31 and is surrounded by the connection portion 21.

[0014] 3, the partition 22 is deformed such that the center of the partition 22 is displaced in the thickness direction of the partition 22 (sheet 2) relative to the connecting portion 21. The partition 22 is formed, for example, in a convex shape that is convex in the direction that it enters the support member 3, but the opposite direction is also possible. The convex shape of the partition 22 is a dome shape, and its cross section is an arc shape.

[0015] In the sheet-like soundproof structure 1 according to this embodiment, the support member 3 is made of resin, and the openings 31 make it easy to form the partitions 22 in the sheet 2. As a result, the cross-sectional ratio of the openings 31 in the support member 3 can be increased, which contributes to reducing the overall mass. Furthermore, the sheet 2 and support member 3 can generally be mass-produced and are relatively inexpensive.

[0016] [Manufacturing Process of Sheet-Like Soundproof Structure 1] Fig. 4A is a diagram showing the state before the sheet 2 is sandwiched in a mold 4 having a cavity 411 for forming the support member 3 in the manufacturing process of the sheet-like soundproof structure 1 of this embodiment. Fig. 4B is a diagram showing the state after the sheet 2 has been sandwiched in the mold 4 in the manufacturing process of the sheet-like soundproof structure 1 of this embodiment. Fig. 4C is a diagram showing the state after molten metal of the material for the support member 3 has been injected into the mold 4 (cavity 411) in the manufacturing process of the sheet-like soundproof structure 1 of this embodiment. Fig. 4D is a diagram showing the state after the molten metal has solidified in the manufacturing process of the sheet-like soundproof structure 1 of this embodiment and the sheet-like soundproof structure 1 has been removed from the mold 4.

[0017] As shown in Figure 4A, the mold 4 for forming the support member 3 that constitutes the sheet-like soundproof structure 1 is divided into a fixed mold 41 and a movable mold 42, and a cavity 411 for forming the support member 3 is formed in the fixed mold 41, and the cavity 411 is open to the surface of the fixed mold 41 that faces the movable mold 42.

[0018] The sheet 2 has partitions 22 formed therein by pressing or the like.

[0019] A recess 412 having a shape conforming to the convex surface of the partition section 22 of the sheet 2 is formed between the two cavities 411 of the fixed mold 41. On the other hand, a protrusion 421 having a shape conforming to the concave surface of the partition section 22 of the sheet 2 is disposed at a position facing the recess 412 of the movable mold 42.

[0020] In addition, a groove-shaped gas vent (not shown) that connects the cavity 411 to the side of the fixed mold 41 is formed on the contact surface of the fixed mold 41 with the sheet 2, and the gas (air) inside the cavity 411 can be discharged to the outside through the gas vent (not shown), allowing the molten metal to be filled into the cavity 411.

[0021] As shown in Figure 4B, when the fixed mold 41 and the movable mold 42 are fastened together with the sheet 2 sandwiched between them, the sheet 2 is pressed in the thickness direction by the fixed mold 41 and the movable mold 42 and further deforms to fit the internal space formed by the recessed portion 412 and the protruding portion 421.

[0022] Molten metal made of the material of the support member 3 is supplied to a sleeve (not shown) attached to the fixed mold 41, and a plunger (not shown) is operated. Then, the molten metal in the sleeve (not shown) is supplied into the cavity 411 via a runner (not shown) as shown in FIG. 4C. The plunger (not shown) continues to press the molten metal, so that the molten metal that has entered the cavity 411 presses against the sheet 2 in the thickness direction and penetrates into the sheet 2 to some extent. The plunger continues to press against the molten metal until the molten metal solidifies.

[0023] After the molten metal has solidified, the operation of the plunger (not shown) is stopped and the fixed die 41 and the movable die 42 are released from the mold 4, thereby allowing the sheet-like soundproof structure 1 to be removed from the mold 4 as shown in Fig. 4D. At this time, the support member 3 (crosspiece 32) remains welded to the sheet 2 (connection portion 21).

[0024] [Model of Transmission Loss of Sheet-Like Soundproof Structure 1 and Frequency Characteristics of Loss] Fig. 5 is a model of the sheet-like soundproof structure 1 for expressing the transmission loss of sound waves input to the sheet-like soundproof structure 1. Fig. 6 is a diagram showing the relationship between sound wave loss and road noise band in the model of Fig. 5 before the surface rigidity is set high, and the relationship between sound wave loss and road noise band in the model of Fig. 5 after the surface rigidity is set high.

[0025] As described above, in the sheet-like soundproof structure 1 of this embodiment, the sheet 2 is divided into a plurality of partitions 22 by the support members 3 (crosspieces 32). Therefore, as shown in Fig. 5, the sheet-like soundproof structure 1 can be considered as a model of a spring vibration system (two vibration systems formed by two adjacent partitions 22 are independent of each other) in which the mass of a partition 22 is "m" and the surface rigidity of the partition 22 (resistance to deformation in response to input) is "k".

[0026] In this case, the transmission loss (TL) when a sound wave (frequency: f) passes from one main surface of the partition 22 to the other main surface can be expressed as follows:

[0027] Transmission loss (TL) resonance frequency (f ０ ) will look like this:

[0028] Here, when the area of ​​the partition 22 is reduced, the mass (m) is reduced and the surface rigidity (k) is increased, so the value of (k / m) is increased. ０ ) increases as the area of ​​the partition 22 decreases.

[0029] Furthermore, in this embodiment, since the partition 22 has a convex shape, the surface rigidity (k) thereof is greater than the surface rigidity when the partition 22 is flat, and the resonant frequency (f ０ ) can be increased.

[0030] As shown in Fig. 6, the transmission loss (TL) (and the insertion loss (IL) described later) of the sheet-like soundproof structure 1 before the surface stiffness (k) is set high (when the partition 22 is flat) has a frequency characteristic based on equation (2) (dashed line in Fig. 6). The transmission loss (TL) is proportional to the resonant frequency (f ０ The minimum value is at the resonant frequency (f ０ In the frequency band below the resonant frequency (f), the transmission loss (TL) increases monotonically as the frequency decreases. ０ ) the transmission loss (TL) increases monotonically with increasing frequency.

[0031] The frequency characteristics (solid line in FIG. 6 ) of the transmission loss (TL) of the sheet-like soundproof structure 1 after the surface rigidity (k) is set high (when the partitions 22 are convex) are shifted to the high frequency side overall compared to the transmission loss of the sheet-like soundproof structure 1 when the partitions 22 are flat, and the resonance frequency is “f ０ " is higher than "f ０ '".

[0032] Therefore, for example, if the object to be soundproofed is a vehicle, and the frequency band (road noise band) of road noise (road surface noise) is the resonance frequency (f ０ ), the frequency characteristics of the transmission loss (TL) of the sheet-like soundproof structure 1 having the partition 22 in a convex shape as described above shifts to the high frequency side, the transmission loss (TL) in the road noise band increases, and the soundproofing performance improves.

[0033] [Example] FIG. 7 is a diagram comparing the insertion loss of a sheet-like soundproof structure 1 of a comparative example in which the partitions 22 are flat with the insertion loss of the sheet-like soundproof structure 1 of this embodiment in which the partitions 22 are convex.

[0034] The inventors of the present application studied the sound wave insertion loss (IL) of a sheet-like soundproof structure of a comparative example and the sheet-like soundproof structure 1 of this embodiment. The same materials were used for the sheet 2 and the support member 3 in both the comparative example and this embodiment. In addition, in both the comparative example and this embodiment, the thickness of the sheet 2 was approximately 400 μm, the thickness of the support member 3 was 10 mm, and the length of the long side (diagonal line) of the opening 31 of the support member 3 was 11 mm.

[0035] Then, sound waves were generated from a speaker (sound source) set inside the soundproof box, and the insertion loss [dB] was measured when the sheet-like soundproof structure 1 was installed and when it was not installed, to evaluate the soundproofing performance. A larger insertion loss value at a certain frequency means better soundproofing performance against sound waves of that frequency.

[0036] The dashed line (A) in FIG. 7 shows the insertion loss estimated when the sheet-like soundproof structure 1 is composed only of the sheet 2 and it is assumed that the soundproofing performance is achieved in accordance with only the mass law.

[0037] The dashed line (B) in FIG. 7 shows the insertion loss estimated when it is assumed that the sheet-like soundproof structure 1, which is composed of the sheet 2 and the support member 3, exhibits soundproofing performance according to only the mass law.

[0038] As shown in FIG. 7, in the comparative example, the resonant frequency (f ０ ) (1600 [Hz]), a peak with an insertion loss higher than that indicated by the dashed line (B) occurs. Peak loss (C) is a vibration mode in which vibration occurs at a wavelength sufficiently longer than the long side (diagonal) of the partition 22, and peak loss (D) is a vibration mode in which the partition 22 and the connection portion 21 vibrate in opposite phases, as described below. In these two vibration modes, the phases of the sound waves generated from one main surface of the sheet-like soundproof structure 1 and the phases of the sound waves generated from the other main surface of the sheet-like soundproof structure 1 are opposite to each other, so the sound waves cancel each other out, resulting in a high peak loss. However, in the comparative example, the insertion loss is low in the frequency band from the resonance frequency (1600 [Hz]) to, for example, 3200 [Hz], making it difficult to effectively block road noise in this frequency band.

[0039] On the other hand, in this embodiment, the partitioning portion 22 has a convex shape, so that the surface rigidity (k) of the partitioning portion 22 is higher than that of the comparative example. ０ ') moves to the high frequency side (4400 [Hz]), and the resonant frequency (f ０The insertion loss in the frequency band (1300 [Hz] - 3800 [Hz]) lower than that of the comparative example is higher.

[0040] The peak loss (F) (2820 [Hz]) is the peak loss (D) shifted to the higher frequency side, but it is the maximum value of the insertion loss in the measurement range. The peak loss (E) is in the same vibration mode as the peak loss (C), but no change in the peak value or frequency was observed.

[0041] [Relationship between Peak Loss Model and Depth / Long Side of Partition 22] Fig. 8 is a diagram showing a vibration model (vibration mode) of peak loss of the sheet-like soundproof structure 1 of this embodiment. Fig. 9 is a diagram showing the relationship between the ratio of the depth of the partition 22 to the long side of the partition 22 and the frequency of peak loss.

[0042] The peak loss (D) and peak loss (F) shown in FIG. 7 are vibrations caused by a circular motion that revolves around an axis that is the direction in which the partitions 22 are arranged (or linear vibrations whose amplitude direction is the thickness direction of the partitions 22), and are caused by a vibration mode in which the partitions 22 and the connecting portions 21 (support member 3) have the same period and are in opposite phase to each other.

[0043] In this vibration mode, the sound waves generated in the partitioning portion 22 by vibration due to the sound waves input from the outside and the sound waves generated in the connecting portion 21 by vibration due to the sound waves input from the outside have the same frequency but are in opposite phases, so they cancel each other out, resulting in a large insertion loss such as peak loss (D) and peak loss (F). In this embodiment, the resonant frequency (f ０ ) is higher than 1473 [Hz], the peak loss associated with the vibration mode (FIG. 8) is likely to appear.

[0044] As shown in Fig. 9, the inventors of the present invention investigated the relationship between the ratio of the depth of the partitions 22 to the long sides of the partitions 22 and the peak frequency of the vibration mode. They found that the peak frequency monotonically increases as the ratio increases. It is also considered that the peak frequency monotonically increases up to a ratio of 0.20.

[0045] [Manufacturing process of a modified example of this embodiment] Fig. 10A is a diagram showing a state in which a sheet 2 is sandwiched in a mold 4 having a cavity 411 for forming the support member 3 in a manufacturing process of a sheet-like soundproof structure 1 of a modified example of this embodiment. Fig. 10B is a diagram showing a state in which molten metal of the material of the support member 3 is injected into the mold 4 (cavity 411) in a manufacturing process of a sheet-like soundproof structure 1 of a modified example of this embodiment. Fig. 10C is a diagram showing a state in which the sheet-like soundproof structure 1 is removed from the mold 4 after the molten metal has solidified in a manufacturing process of a sheet-like soundproof structure 1 of a modified example of this embodiment.

[0046] 10A , unlike the basic form, the modified example does not have the recessed portion 412 of the fixed mold 41 and the protruding portion 421 of the movable mold 42, and the portion between the cavities 411 of the fixed mold 41 and the movable mold 42 is flat. Furthermore, the sheet 2 is sandwiched between the fixed mold 41 and the movable mold 42 in a flat state.

[0047] Molten metal made of the material of the support member 3 is supplied to a sleeve (not shown) attached to the fixed mold 41, and a plunger (not shown) is operated. Then, the molten metal in the sleeve (not shown) is supplied via a runner (not shown) into the cavity 411 as shown in FIG. 20B . The plunger (not shown) continues to press the molten metal, so that the molten metal that has entered the cavity 411 presses against the sheet 2 in its thickness direction and penetrates into the sheet 2 to some extent. As a result, the sheet 2 is pushed to the periphery by the pressure from the molten metal (support member 3 after solidification), and as a result, the portion of the sheet 2 that will become the partition portion 22 is subjected to stress that makes the portion convex in the direction away from the molten metal (support member 3 after solidification).

[0048] After the molten metal has solidified, the operation of the plunger (not shown) is stopped and the fixed die 41 and the movable die 42 are released from the mold 4, thereby allowing the sheet-like soundproof structure 1 to be removed from the mold 4 as shown in Fig. 4D. At this time, the stress causes the partition portion 22 of the sheet 2 to deform into a convex shape that is convex in the thickness direction of the sheet 2 and in the direction away from the support member 3.

[0049] [Modifications of Partition Section 22] Fig. 11 is a cross-sectional view of a first modification of the partition section 22 of this embodiment. Fig. 12 is a cross-sectional view of a second modification of the partition section 22 of this embodiment.

[0050] In the first modified example, the partition 22 has a conical shape with a triangular cross section. In the second modified example, the partition 22 has a mortar shape with a trapezoidal cross section. Both shapes can be formed by press molding, and the surface rigidity (k) can be increased.

[0051] [Effects of this embodiment] The sheet-like soundproof structure 1 of this embodiment includes an elastic sheet 2 and a support member 3 that supports the sheet 2 by connecting to a main surface of the sheet 2, the support member 3 including a plurality of openings 31 arranged to face the sheet 2, the sheet 2 including a connection portion 21 that is connected to the support member 3 and has a shape that follows the connection surface of the support member 3 that connects to the sheet 2, and a partition portion 22 that faces the opening 31 and is surrounded by the connection portion 21, and the partition portion 22 is deformed such that the center of the partition portion 22 is displaced in the thickness direction of the partition portion 22 relative to the connection portion 21.

[0052] With the above configuration, the frequency band with high sound wave insertion loss can be shifted to a higher position than the frequency band when the partition portion 22 is flat, resulting in a sheet-like soundproofing structure 1 in which the cutoff frequency band can be set according to the frequency band of the sound waves to be soundproofed.

[0053] In this embodiment, the surface rigidity (k) of the partitions 22 and the surface density (m) of the partitions 22 satisfy the formula (4). The above configuration makes it easier for a high peak loss to occur due to the vibration mode (FIG. 8).

[0054] In this embodiment, the cross-sectional shape of the partition 22 is an arc, a triangle, or a trapezoid.

[0055] With the above configuration, the design of the partition section 22 can be created to meet the user's requirements.

[0056] In this embodiment, the partition 22 has a mortar or cone shape.

[0057] With the above configuration, the design of the partition section 22 can be created to meet the user's requirements.

[0058] In this embodiment, the ratio of the displacement in the thickness direction from the connection portion 21 at the center of the partition portion 22 to the long side (diagonal line) of the partition portion 22 is set to be higher than 0 and equal to or less than 0.2.

[0059] With the above configuration, the high peak loss of the insertion loss due to the vibration mode (FIG. 8) can be set in the desired frequency band.

[0060] In this embodiment, the support member 3 (the crosspiece 32 ) is welded to the connection portion 21 .

[0061] With the above-described configuration, the support member 3 can be firmly connected to the sheet 2, and the vibration mode components due to the connecting portion 21 and the partition portion 22 can be enhanced.

[0062] In this embodiment, the partition 22 has a shape that is convex in the direction that enters the opening 31 .

[0063] With the above-described configuration, the overall thickness of the sheet-like soundproof structure 1 can be reduced, and interference with the object to which it is attached can be reduced.

[0064] In this embodiment, the partitioning portion 22 and the connecting portion 21 vibrate due to sound waves and have a vibration mode (FIG. 8) in which the partitioning portion 22 and the connecting portion 21 vibrate in opposite phases to each other, and the resonant frequency of the vibration mode (FIG. 8) can be adjusted by changing the ratio.

[0065] In the above configuration, a vibration occurs due to a circular motion around the axis along which the partitions 22 are arranged (or a linear vibration with the thickness direction of the partitions 22 as the amplitude direction), in which the partitions 22 and the connecting portions 21 (support member 3) vibrate at the same period and the partitions 22 and the connecting portions 21 vibrate in opposite phases (FIG. 8). In this vibration mode (FIG. 8), the sound waves generated in the partitions 22 due to vibration caused by externally input sound waves and the sound waves generated in the connecting portions 21 due to vibration caused by externally input sound waves have the same frequency but are in opposite phases, so they cancel each other out, resulting in a large insertion loss (such as peak loss (D) and peak loss (F)). Therefore, with the above configuration, a peak loss with a high insertion loss due to the vibration mode (FIG. 8) can be set in a desired frequency band.

[0066] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. A sheet-like soundproofing structure comprising: an elastic sheet; and a support member that supports the sheet by connecting to a main surface of the sheet, wherein the support member has a plurality of openings arranged to face the sheet; the sheet comprises a connection portion that is connected to the support member and has a shape that follows the connection surface of the support member that connects to the sheet; and a partition portion that faces the opening and is surrounded by the connection portion, wherein the partition portion is deformed so that a center portion of the partition portion is displaced in the thickness direction of the partition portion relative to the connection portion.

2. A sheet-like soundproof structure according to claim 1, wherein the surface rigidity (k) of the partitions and the surface density (m) of the partitions satisfy the formula (1).

3. A sheet-like soundproof structure according to claim 1, wherein the cross-sectional shape of the partition is arc-shaped, triangular, or trapezoidal.

4. A sheet-like soundproof structure according to claim 1, wherein the partition has a mortar or cone shape.

5. A sheet-like soundproof structure according to claim 1, wherein the ratio of the displacement in the thickness direction from the connecting portion of the central portion to the long side of the partition portion is set to be higher than 0 and not higher than 0.

2.

6. The sheet-like soundproof structure according to claim 1, wherein the support member is welded to the connecting portion.

7. A sheet-like soundproof structure according to claim 1, wherein the partition has a shape that is convex in the direction that it enters the opening.

8. A sheet-like soundproof structure as described in claim 5, wherein the partitions and the connecting parts vibrate in response to sound waves and have a vibration mode in which the partitions and the connecting parts vibrate in opposite phases to each other, and the resonant frequency of the vibration mode can be adjusted by changing the ratio.

Images