JP2019136887A - Sound absorption structure - Google Patents

Abstract

To provide a sound absorption structure excellent in sound absorption performance.SOLUTION: A sound absorption structure 1 has a film 50 stuck to a surface 10a of a hollow plate material 10. The hollow plate material 10 comprises: a plurality of cells S partitioned by side walls 23 extending in a thickness direction of the hollow plate material 10; and closing walls 21, 30 for closing ends of the cells S. The film 50 is stuck to surfaces of the closing walls 21, 30. On a surface 1a on the film 50 side, a plurality of communication holes 15 penetrating the closing walls 21, 30 and the film 50 for communicating inner regions of the cells S and an outer region of the film 50, are provided. The thickness of the film 50 is thinner than the thickness of the closing walls 21, 30, and the film 50 is stuck to the hollow plate material 10 by an adhesive agent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sound absorbing structure in which a film is attached to the surface of a hollow plate material.

In some cases, a sound absorbing plate obtained by attaching a design film to the surface of a plate material having sound absorbing performance is used as a wall member such as a sound absorbing chamber.
Patent Document 1 describes an invention relating to a sound absorbing plate in which a decorative sheet made of a vinyl chloride sheet or the like is attached to a plate made of a porous material such as glass wool board. The sound absorbing plate described in Patent Document 1 has a large number of small holes formed on the surface side of the decorative sheet by piercing a plurality of needle-like perforating pins in order to improve the sound absorbing performance.

JP-A-8-174495

  By the way, it is known to use a hollow plate material in which a plurality of cells are partitioned inside as a sound absorbing plate. As shown in FIG. 7, the hollow plate member 80 includes, for example, a plurality of cells S ′ partitioned by side walls 82 extending in the thickness direction, and closed walls 81 that close the ends of the cells S ′. When such a hollow plate member 80 is used as a wall member such as a sound absorbing chamber, an adhesive is applied to the blocking walls 81 of the plurality of cells S ′ and a design film 83 is pasted, and the blocking wall 81 and the design are applied to the surface of the design film 83. A large number of small holes (communication holes 84) penetrating the film 83 are formed. Thereby, the inside and outside of the cell S ′ are communicated by a large number of small holes (communication holes 84), and the sound absorbing performance of the hollow plate 80 is obtained.

  However, in such a hollow plate member 80, as shown in FIG. 7, since the inside of the cell S ′ is hollow, the design film 83 attached with the adhesive may be displaced when the punch pin is pierced. is there. In particular, when the design film 83 is thin, a small hole is formed in the blocking wall 81 as in the cell S ′ shown in the center of FIG. 7, while the design film 83 is positioned by the pressure at the tip of the punch pin. In some cases, it shifts and expands, and enters the cell S ′ from the small hole formed in the blocking wall 81. Therefore, it is difficult to form small holes on the surface of the design film 83. Further, even if a small hole is formed in the design film 83 as in the cell S ′ shown on the left and right in FIG. 7, the extended design film 83 enters the small hole of the blocking wall 81, and the cell S There may be a case where the opening area of the communication hole 84 communicating between the inside and the outside of the ′ becomes small. Therefore, it is difficult to sufficiently communicate the inside and outside of the cell S ′. As a result, there is a problem that a desired sound absorbing performance cannot be obtained.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a sound absorbing structure excellent in sound absorbing performance.

  In order to solve the above problems, the sound absorbing structure of the present invention is a sound absorbing structure in which a film is attached to the surface of a hollow plate, and the hollow plate is partitioned by side walls extending in the thickness direction of the hollow plate. A plurality of cells and a blocking wall that closes an end of the cell, and the film is attached to a surface of the blocking wall, and the film-side surface penetrates the blocking wall and the film. A plurality of communication holes for communicating the inner area of the cell and the outer area of the film, the thickness of the film is smaller than the thickness of the blocking wall, and the film is attached to the hollow plate by an adhesive. It is attached.

  According to said structure, the film is affixed on the surface of the obstruction | occlusion wall in the hollow board | plate material provided with the some cell divided by the side wall extended in the thickness direction, and the obstruction | occlusion wall which obstruct | occludes the edge part of a cell. It has been. Therefore, the film is firmly attached to the blocking wall.

  Here, the adhesive means a material in a molten state that is cured by heat, light, a chemical reaction, moisture, or the like, and that the materials to be adhered are fixed by being cured. Since the sound absorbing structure has a film attached to the surface of the hollow plate with an adhesive, the hollow plate and the film are firmly fixed with the adhesive. Therefore, the positional deviation between the hollow plate material and the film is suppressed, and the behavior of the hollow plate material and the film such that only the film is extended is suppressed. Thereby, the several communicating hole penetrated by the film side surface is the state which penetrated the obstruction | occlusion wall and the film, and connected the inside and outside of the cell. In the vicinity of such a communication hole, air vibrates violently, and the vibration of the air is consumed as thermal energy as the air rubs against the peripheral portion of the communication hole. Therefore, a sound absorbing structure excellent in sound absorbing performance can be obtained.

In the above sound absorbing structure, the blocking wall preferably has a multilayer structure.
In the above sound absorbing structure, the thickness of the film is preferably 10 to 500 μm.

In the above sound absorbing structure, the adhesive is preferably a hot melt adhesive.
In the above sound absorbing structure, the adhesive is preferably polyurethane reactive.

  According to the present invention, a sound absorbing structure having excellent sound absorbing performance can be obtained.

(A) is a perspective view of a sound absorbing structure, (b) is a β-β line sectional view in (a), and (c) is a γ-γ line sectional view in (a). The figure explaining the process of manufacturing a hollow plate material. (A) is a perspective view of the sheet material which comprises the core layer of a hollow board material, (b) is a perspective view which shows the state in the middle of folding of the same sheet material, (c) is a perspective view which shows the state which folded the same sheet material (D) is sectional drawing of a hollow board material. (A)-(d) is a figure explaining the process of sticking a film on a hollow plate material. The figure explaining the process of forming a communicating hole in a sound absorption structure. The elements on larger scale of the part in which the communicating hole was formed. (A), (b) is a figure explaining the example of a change of a hollow structure. The figure explaining the conventional sound-absorbing structure in which the communicating hole was formed.

Hereinafter, embodiments of the sound absorbing structure of the present invention will be described.
As shown in FIG. 1A, in the sound absorbing structure 1 of the present embodiment, a film 50 is attached to one surface 10a of a plate-shaped hollow plate 10 in which a plurality of cells S are arranged in parallel. Configured. The film 50 is a film having a design property that improves the pattern and color of the surface of the hollow plate 10. Such patterns and colors are formed by, for example, printing applied to the film 50, embossing, embossing, or coloring of the film 50 itself, thereby imparting design properties to the surface of the film 50. ing. The sound absorbing structure 1 is used, for example, as a wall material of a sound absorbing chamber, and is arranged so that the surface on which the film 50 is attached is a design surface and the design surface constitutes the inner surface of the sound absorbing chamber.

  The hollow plate material 10 is formed of a conventionally known thermoplastic resin material. The material is not particularly limited, and examples thereof include polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, and acrylonitrile-butadiene-styrene. The film 50 is made of a conventionally known thermoplastic resin material. The material is not particularly limited, and examples thereof include polypropylene, polyethylene, polyvinyl chloride, and polyethylene terephthalate. The thickness of the film 50 is preferably 10 μm to 500 μm, and more preferably 50 μm to 300 μm. In this embodiment, the thickness of the film 50 is formed to about 200 μm.

First, the structure of the hollow plate 10 will be described.
As shown in FIG. 1 (a), the hollow plate 10 is bonded to the core layer 20 in which a plurality of cells S are arranged in parallel, and to both surfaces in the thickness direction of the core layer 20 (upper and lower surfaces in FIG. The sheet-like skin layers 30 and 40 are formed. As shown in FIGS. 1B and 1C, the core layer 20 is formed by folding a sheet of thermoplastic resin formed into a predetermined shape. The core layer 20 includes an upper wall portion 21, a lower wall portion 22, and a side wall portion 23 that is provided between the upper wall portion 21 and the lower wall portion 22 to partition the cell S into a hexagonal column shape. Has been.

  As shown in FIG. 1B and FIG. 1C, the cells S partitioned in the core layer 20 include first and second cells S1 and S2 having different configurations. As shown in FIG. 1B, in the first cell S <b> 1, the upper wall portion 21 having a two-layer structure is provided above the side wall portion 23. Each layer of the upper wall portion 21 of this two-layer structure is joined to each other. In the first cell S <b> 1, a lower wall portion 22 having a one-layer structure is provided below the side wall portion 23. On the other hand, as shown in FIG.1 (c), in the 2nd cell S2, the upper wall part 21 of 1 layer structure is provided in the upper part of the side wall part 23. As shown in FIG. In the second cell S <b> 2, a lower wall portion 22 having a two-layer structure is provided below the side wall portion 23. The layers of the lower wall portion 22 of this two-layer structure are joined to each other. Moreover, as shown in FIG.1 (b) and FIG.1 (c), between the adjacent 1st cell S1 and between adjacent 2nd cell S2, each side wall part 23 of a two-layer structure is shown. It is divided by.

  As shown in FIG. 1A, the first cells S1 are arranged side by side so as to form a row along the X direction. When viewed from the top, the two adjacent first cells S1 are hexagonal ones. Sharing sides. Similarly, the second cells S2 are arranged side by side so as to form a column along the X direction. When viewed from above, the two adjacent second cells S2 share one side of the hexagon. The columns of the first cells S1 and the columns of the second cells S2 are alternately arranged in the Y direction orthogonal to the X direction. And by these 1st cell S1 and 2nd cell S2, the core layer 20 has comprised the honeycomb structure as a whole.

  As shown in FIGS. 1A to 1C, a skin layer 30 that is a sheet material made of a thermoplastic resin is bonded to the upper surface of the core layer 20 configured as described above. Further, a skin layer 40 that is a sheet material made of a thermoplastic resin is joined to the lower surface of the core layer 20. In this embodiment, the upper portion of the side wall portion 23 in the core layer 20 is closed by the upper wall portion 21 and the skin layer 30 of the core layer 20. That is, the upper wall portion 21 and the skin layer 30 constitute the upper blocking wall 11 that partitions the cell S from the upper side. Similarly, the lower part of the side wall part 23 in the core layer 20 is closed by the lower wall part 22 and the skin layer 40 of the core layer 20. That is, the lower wall portion 22 and the skin layer 40 constitute the lower blocking wall 12 that partitions the cell S from the lower side.

  The hollow plate member 10 has a shape in which a plurality of cells S are arranged inside by the core layer 20 and the skin layers 30 and 40, and the upper blocking wall 11 side of the hollow plate member 10 forms the surface 10a, and the lower blocking member 10 The wall 12 side constitutes the surface 10b.

  As shown in FIG. 1A to FIG. 1C, the sound absorbing structure 1 of the present embodiment is configured by attaching a film 50 to a surface 10 a of the hollow plate member 10 on the upper closing wall 11 side. Yes. That is, the film 50 is attached to the upper blocking wall 11 that closes the end of the cell S at the upper part of the hollow plate 10. As described above, the first cell S <b> 1 and the second cell S <b> 2 that are arranged in parallel with the hollow plate member 10 are different in the configuration of the upper blocking wall 11 that closes the end portion thereof, and thus the film 50 is pasted. The configuration of the upper blocking wall 11 is different between the first cell S1 and the second cell S2. In the cell S1 of the hollow plate member 10, the film 50 is attached to the upper blocking wall 11 formed by joining the skin layer 30 to the upper wall portion 21 of the two-layer structure. In the cell S2, the film 50 is The skin layer 30 is bonded to the upper blocking wall 11 formed by joining the upper wall portion 21 having a one-layer structure.

  As shown in FIG. 1A to FIG. 1C, the hollow plate material 10 and the film 50 are attached via an adhesive layer 60. A conventionally well-known thing can be used for the adhesive agent which comprises the contact bonding layer 60, The kind is not specifically limited. Either an organic adhesive or an inorganic adhesive may be used. In the case of an organic adhesive, either a synthetic adhesive or a natural adhesive may be used. Moreover, in the case of an organic synthetic adhesive, a thermoplastic adhesive, a thermosetting adhesive, an elastomer adhesive, and the like may be mentioned, and any of these may be used. Among these various adhesives, thermoplastic adhesives, so-called hot melt adhesives are preferable.

  Examples of the hot melt adhesive include polyurethane adhesives, ethylene vinyl acetate resin adhesives, vinyl acetate resin adhesives, acrylic resin adhesives, cellulose adhesives, and the like. Among these, polyurethane reactive is preferable because it can be melted by heating and kept in a cured state by reheating after cooling.

  The thickness of the adhesive layer 60 is preferably 2 μm to 100 μm, and more preferably 3 μm to 50 μm. In the present embodiment, the thickness of the adhesive layer 60 is about 5 μm.

  As shown in FIGS. 1B and 1C, a plurality of communication holes 15 are provided through the surface 1 a on the side where the film 50 is attached in the sound absorbing structure 1. The communication hole 15 passes through the film 50 and the upper blocking wall 11 of the hollow plate 10, and communicates the inner region of the cell S arranged in parallel with the hollow plate 10 and the outer region of the film 50. Specifically, as shown in FIG. 1B, in the first cell S1, the communication hole 15 passes through the upper wall portion 21, the upper skin layer 30, and the film 50 having a two-layer structure. As shown in FIG. 1C, the communication hole 15 in the second cell S2 passes through the upper wall portion 21, the skin layer 30 on the upper surface side, and the film 50 having a single layer structure. Thereby, the sound absorbing structure 1 functions as a sound absorbing material.

  As shown in FIG. 1A, one communication hole 15 is provided for each cell S. Although the formation position and the number of the communication holes 15 are not particularly limited, in this embodiment, the sound absorbing structure 1 is located at the center of the hexagonal shape of each cell S when viewed from above.

  Further, the shape and size of the communication hole 15 as viewed from above are not particularly limited. Examples of the top view shape include a circular shape, an elliptical shape, and a polygonal shape. As shown in FIG. 1B and FIG. 1C, in this embodiment, it is formed in a circular shape when viewed from above, and the diameter of the opening of each communication hole 15 is six when the cell S is viewed from above. It is set below the length of one side of the square. Specifically, the diameter of the opening of each communication hole 15 is set to a fraction (for example, about 0.5 to 3.0 mm) of the interval P1 between the centers of the cells S adjacent in the X direction. .

  Next, the manufacturing method of the sound absorption structure 1 of this embodiment is demonstrated. The sound absorbing structure 1 includes a step of manufacturing the hollow plate member 10, a step of applying the film 50 while applying an adhesive to one surface 10 a of the hollow plate member 10, and a film of the sound absorbing structure 1 after the adhesive is cured. This includes a step of penetrating the communication hole 15 in the surface 10a on the 50 side.

First, the process of manufacturing the hollow plate 10 will be described with reference to FIG.
As shown in FIG. 2A, the first sheet material 100 is formed by molding a single thermoplastic resin sheet into a predetermined shape. The thickness of the first sheet material 100 is preferably 0.1 mm to 0.6 mm, and more preferably 0.2 mm to 0.3 mm. In the present embodiment, the thickness of the first sheet material 100 is about 0.3 mm.

  In the first sheet material 100, strip-shaped planar regions 110 and bulging regions 120 are alternately arranged in the longitudinal direction (X direction) of the first sheet material 100. In the bulging region 120, a first bulging portion 121 having a cross-section downward groove shape composed of an upper surface and a pair of side surfaces is formed over the entire extending direction (Y direction) of the bulging region 120. The angle formed between the upper surface and the side surface of the first bulge portion 121 is preferably 90 degrees. As a result, the cross-sectional shape of the first bulge portion 121 is a downward U-shape. Further, the width of the first bulging portion 121 (the length of the upper surface in the short direction) is equal to the width of the planar region 110, and the bulging height of the first bulging portion 121 (the length of the side surface in the short direction). ) Is set to be twice as long.

  Further, in the bulging region 120, a plurality of second bulging portions 122 having a trapezoidal shape obtained by dividing the regular hexagon by the longest diagonal line in the bulging region 120 are orthogonal to the first bulging portion 121. Is formed. The bulge height of the second bulge portion 122 is set to be equal to the bulge height of the first bulge portion 121. Further, the interval between the adjacent second bulging portions 122 is equal to the width of the upper surface of the second bulging portion 122.

  The first bulging portion 121 and the second bulging portion 122 are formed by partially bulging the sheet upward using the plasticity of the sheet. The first sheet material 100 can be formed from one sheet by a known forming method such as a vacuum forming method or a compression forming method.

  As shown in FIGS. 2A and 2B, the core layer 20 is formed by folding the first sheet material 100 configured as described above along the boundary lines P and Q. Specifically, the first sheet material 100 is valley-folded at the boundary line P between the planar region 110 and the bulging region 120 and the mountain is formed at the boundary line Q between the upper surface and the side surface of the first bulging portion 121. Fold and compress in the X direction. Then, as shown in FIGS. 2B and 2C, the upper surface and the side surface of the first bulge portion 121 are folded, and the end surface of the second bulge portion 122 and the planar region 110 are folded. , One prismatic partition 130 extending in the Y direction with respect to one bulging region 120 is formed. The hollow plate-like core layer 20 is formed by continuously forming the partition bodies 130 in the X direction. In this embodiment, the direction in which the first sheet material 100 is compressed to fold is the direction in which the cells S are arranged in parallel (X direction).

  When the first sheet material 100 is compressed as described above, the upper wall portion 21 of the core layer 20 is formed by the upper surface and the side surface of the first bulge portion 121, and the end surface and the plane of the second bulge portion 122 are flat. The region 110 and the lower wall portion 22 of the core layer 20 are formed. As shown in FIG. 2C, the upper wall 21 has a portion where the upper surface and the side surface of the first bulge 121 are folded to form a two-layer structure, and the second bulge in the lower wall 22. A portion where the end surface 122 and the planar region 110 are folded to form a two-layer structure is an overlapping portion 131.

  In addition, the hexagonal column-shaped region that is partitioned and formed by folding the second bulging portion 122 becomes the second cell S2, and the hexagonal column-shaped region that is partitioned and formed between a pair of adjacent partitions 130 is the first cell S2. One cell S1 is obtained. In the present embodiment, the upper surface and the side surface of the second bulge portion 122 constitute the side wall portion 23 of the second cell S2, and the second bulge in the bulge region 120 and the side surface of the second bulge portion 122. The planar portion located between the portions 122 constitutes the side wall portion 23 of the first cell S1. And the contact part of the upper surfaces of the 2nd bulging part 122 and the contact part of the said plane parts in the bulging area | region 120 become the side wall part 23 which makes | forms 2 layer structure. In the first cell S1, the upper portion is partitioned by a pair of overlapping portions 131, and in the second cell S2, the lower portion is partitioned by a pair of overlapping portions 131. In addition, when implementing such a folding process, it is preferable to make the 1st sheet material 100 into the state softened by heat processing.

  As shown in FIG.2 (d), the 2nd sheet material made from a thermoplastic resin is joined to the upper surface and lower surface of the core layer 20 obtained in this way, respectively by heat welding. The second sheet material joined to the upper surface of the core layer 20 becomes the skin layer 30 and constitutes the upper closing wall 11 that closes the cell S from the upper side together with the upper wall portion 21 of the core layer 20. The second sheet material bonded to the lower surface of the core layer 20 becomes the skin layer 40 and constitutes the lower blocking wall 12 that closes the cell S from the lower side together with the lower wall portion 22 of the core layer 20. The thickness of the second sheet material, that is, the skin layers 30 and 40 is preferably 0.1 mm to 1.5 mm, and more preferably 0.3 mm to 1.0 mm. In the present embodiment, the thickness of the skin layers 30 and 40 is about 1.0 mm. FIG. 2D shows the cell S2.

  When the second sheet material (skin layers 30 and 40) is thermally welded to the core layer 20, the upper wall portion 21 (overlapping portion 131) of the two-layer structure in the first cell S1 is thermally welded to each other. Similarly, the lower wall part 22 (overlapping part 131) of the two-layer structure in the second cell S2 is thermally welded to each other.

  By the above steps, a plurality of first cells S1 or second cells S2 are arranged in a row in the X direction, and a plurality of first cells S1 and second cells S2 are alternately arranged in the Y direction. A plate 10 is obtained.

  Next, the process of applying the film 50 while applying an adhesive to one surface 10a of the hollow plate 10 will be described with reference to FIG. The application of the adhesive 61 and the application of the film 50 supply the belt conveyor B that moves the hollow plate 10 laterally, the application part C that applies the molten hot melt adhesive 61 to the hollow plate 10, and the film 50. This is performed as a series of steps by the apparatus A including the film supply unit F and the pair of press rolls R that sandwich the hollow plate 10 and the film 50. In FIG. 3, the apparatus A and the hollow plate material 10 are shown as a schematic diagram. In each of FIGS. 3A to 3D, only the portions necessary for the description in the apparatus A are shown, and the portions not necessary for the description are omitted.

  In the apparatus A, the coating unit C and the film supply unit F are arranged in order from the upstream side above the belt conveyor B, and a pair of press rolls R are arranged in the vicinity of the downstream side of the film supply unit F so as to face each other. Yes. The distance between the pair of opposed press rolls R is set to be approximately the same as the thickness of the hollow plate 10.

  As shown in FIG. 3A, a hollow plate material 10 cut to a predetermined size is prepared and placed on the belt conveyor B on the upstream side of the application part C. The belt conveyor B is driven at a predetermined speed, and the mounted hollow plate 10 moves toward the downstream side at a predetermined speed as indicated by an arrow in FIG.

  As shown in FIG. 3 (b), in the application part C where the hot melt adhesive 61 is applied, the hot melt adhesive 61 heated to a predetermined temperature and in a molten state is placed on the surface 10 a of the hollow plate 10. Supply. The application part C is configured such that the hot-melt adhesive 61 in a molten state is applied with a constant thickness over the entire width direction of the surface 10 a of the hollow plate 10. The hot melt adhesive 61 applied to the surface 10 a of the hollow plate 10 forms an adhesive layer 60.

  As shown in FIG. 3C, the film 50 is supplied from the film supply unit F disposed on the downstream side of the application unit C to the portion of the hollow plate 10 where the adhesive layer 60 is formed. Since the film supply unit F is disposed at a position close to the coating unit C, the hot melt adhesive 61 that forms the adhesive layer 60 is held in a molten state in the portion where the film 50 is supplied. The film 50 supplied from the film supply unit F is placed on the surface 10 a of the hollow plate 10 via the adhesive layer 60.

  As shown in FIGS. 3C and 3D, the hollow plate 10 on which the film 50 is placed moves downstream between a pair of press rolls R arranged at positions close to the film supply unit F. Moving. Since the distance between the pair of press rolls R is set to be approximately the same as the thickness of the hollow plate material 10, the hollow plate material 10 on which the film 50 is placed is pressed by the press roll R in the thickness direction. When the hollow plate 10 on which the film 50 is placed moves further downstream, the hot-melt adhesive 61 that forms the adhesive layer 60 is cooled and cured. Thereby, the sound-absorbing structure 1 in which the film 50 is bonded to the surface 10a of the hollow plate 10 via the adhesive layer 60 is obtained.

The sound absorbing structure 1 thus obtained is cured by being left at room temperature in a state where a plurality of the sound absorbing structures 1 are sequentially stacked.
Next, the process of penetrating the communication hole 15 in the surface 10a on the film 50 side of the sound absorbing structure 1 will be described with reference to FIG. The through hole 15 is formed by installing the sound absorbing structure 1 below a plurality of penetration jigs T attached at predetermined intervals.

  The communication hole 15 is formed by penetrating a penetration jig T such as a drill, a needle, or a punch through the film 50 and the upper blocking wall 11 of the sound absorbing structure 1. As shown in FIG. 4, a plurality of penetration jigs T are arranged at substantially the same intervals as the intervals between the centers of adjacent cells S. The sound absorbing structure 1 is arranged and fixed below the penetrating jig T, and the penetrating jig T is moved downward. In this way, one communication hole 15 is formed in the substantially central portion of each cell S in the film 50 and the upper blocking wall 11 of the sound absorbing structure 1.

  Through the above steps, the sound absorbing structure 1 in which the film 50 is attached to the surface 10a of the hollow plate member 10 and the communication hole 15 that communicates the inside and outside of the cell S is formed on the surface on which the film 50 is attached. Is manufactured. The sound absorbing structure 1 of the present embodiment has a plate thickness of about 20 mm.

Next, the operation of the sound absorbing structure 1 in which the communication hole 15 is provided will be described.
The sound absorbing structure 1 of the present embodiment has a cell 10 at the surface 10a of the hollow plate 10 in which a plurality of cells S are juxtaposed, specifically, at the end of the side wall portion 23 that partitions the plurality of cells S. A film 50 is attached to the surface 10 a on the upper closing wall 11 side to be closed via an adhesive layer 60. The communication hole 15 is formed by passing a penetration jig T through the film 50 and the upper blocking wall 11.

  Since the adhesive layer 60 is formed by applying and curing polyurethane reactive which is a hot-melt adhesive, the film 50 is firmly fixed to the surface 10 a of the upper blocking wall 11. Therefore, when the penetrating jig T is passed through the film 50 and the upper closing wall 11, the position of the film 50 firmly fixed to the upper closing wall 11 is unlikely to occur. As a result, as shown in FIG. 5, the communication hole 15 is punched so that the end edge of the film 50 is substantially at the same position as the end edge of the upper blocking wall 11.

  In the case where the design film 83 is attached to the conventional hollow plate member 80 shown in FIG. 7 with an adhesive, the design film 83 is likely to be displaced, and the design film is formed inward of the edge of the blocking wall 81 in the communication hole 84. As a result, the edge of 83 enters and the hole diameter of the communication hole 84 becomes small (left and right cells S ′ in FIG. 7). The edge of the design film 83 that has entered the communication hole 84 is easily stretched and whitened by the pressure from the penetration jig T.

  In this respect, in the sound absorbing structure 1 of the present embodiment, the situation in which the edge of the film 50 enters the inside of the edge of the upper blocking wall 11 is suppressed, and the communication hole 15 having a desired shape and size is formed. ing. Moreover, it is suppressed that the edge of the film 50 is extended and whitened. The communication hole 15 is provided in such a manner that the inner area of the cell S and the outer area of the film 50 communicate with each other, and an excellent sound absorbing performance is realized by designing the communication hole 15 to have a desired shape and size. be able to.

  In the sound absorbing structure 1 of the present embodiment, the thickness of the first sheet material 100 that forms the core layer 20 of the hollow plate 10 is about 0.3 mm, and the thickness of the second sheet material that forms the skin layers 30 and 40 is about It is formed to 1.0 mm. Therefore, in the cell S1 of the hollow plate member 10, the upper blocking wall 11 formed by joining the skin layer 30 to the upper wall portion 21 of the two-layer structure has a thickness of about 1.6 mm. In the cell S2, the upper blocking wall 11 formed by bonding the skin layer 30 to the upper wall portion 21 having a single layer structure in the film 50 has a thickness of about 1.3 mm. On the other hand, the film 50 attached to the upper blocking wall 11 has a thickness of about 200 μm, and is formed thinner than the upper blocking wall 11 blocking the cell S1 and the upper blocking wall 11 blocking the cell S2. Yes.

  In the case where the design film 83 is pasted with an adhesive as in the conventional hollow plate member 80 shown in FIG. 7, even if the communication hole is formed in the blocking wall 81, the design film 83 is caused by the pressure from the penetrating jig. As a result, the design film 83 is not easily formed with a communication hole (center cell S ′ in FIG. 7). In this respect, in the sound absorbing structure 1 of the present embodiment, since the film 50 is firmly fixed to the upper blocking wall 11, even if the film 50 is thin, the film 50 is not easily displaced or stretched. A communication hole 15 having the same size and shape as the upper blocking wall 11 is formed.

According to the said embodiment, there exist the following effects.
(1) In the sound absorbing structure 1 of the above embodiment, the film 50 is adhered to the upper closing wall 11 that closes the cells S in the hollow plate material 10 in which a plurality of cells S are arranged in parallel. 50 and the communication hole 15 which penetrates the upper obstruction | occlusion wall 11 are penetrated. Therefore, the upper blocking wall 11 and the film 50 are firmly fixed, and the positional displacement of the film 50 with respect to the upper blocking wall 11 hardly occurs. The situation in which the edge of the film 50 enters the inside of the communicating hole 15 provided through is suppressed, and the edge of the film 50 enters the inside of the communicating hole 15 to block the communication hole 15 or make it difficult to communicate. Is suppressed. The inside and outside of the cell S communicate with each other through the communication hole 15, and the sound absorbing structure 1 having excellent sound absorbing performance is obtained.

  (2) In the sound absorbing structure 1 of the above embodiment, the thickness of the film 50 is thinner than the thickness of the upper blocking wall 11. When the communication hole 15 is formed, if the pressure by the penetration jig T is applied to the surface 10 a side of the sound absorbing structure 1, the thin film 50 is easier to extend than the thick upper blocking wall 11. In this respect, since the film 50 is firmly fixed to the upper blocking wall 11 with an adhesive, the situation in which the film 50 extends with respect to the upper blocking wall 11 is suppressed. Even if the thin film 50 is affixed, the communication hole 15 having a desired shape and size can be formed.

  (3) In the sound absorbing structure 1 of the present embodiment, the upper blocking wall 11 of the hollow plate member 10 has a multilayer structure formed by joining the skin layer 30 to the upper wall portion 21 of the two-layer structure in the cell S1. ing. The cell S2 has a multilayer structure in which the skin layer 30 is joined to the upper wall portion 21 having a single-layer structure. The upper wall portion 21 and the skin layer 30 constituting the multilayer structure are joined to each other by thermal welding. Therefore, the strength of the upper blocking wall 11 is improved as compared with that having a single-layer structure.

  (4) In the sound absorbing structure 1 of the above embodiment, the adhesive forming the adhesive layer 60 is a hot melt adhesive. Therefore, if it is in a state of being heated and melted, it can be easily applied onto the surface 10 a of the hollow plate 10. Moreover, since it hardens | cures by cooling, the hollow plate material 10 and the film 50 are fixed firmly.

  (5) In the sound absorbing structure 1 of the above embodiment, the adhesive forming the adhesive layer 60 is polyurethane reactive. Therefore, even if heat is applied after curing, the cured state can be maintained. The fixed state of the hollow plate 10 and the film 50 is not easily affected by heat, and the film 50 is difficult to peel off.

  (6) In the sound absorbing structure 1 of the above embodiment, the film 50 is attached to the hollow plate member 10 via the adhesive layer 60 of about 5 μm. When the adhesive layer 60 is as thin as about 5 μm, if the thickness of the attached film 50 is thick, a portion having a low bonding strength may occur due to a thickness tolerance. In this respect, since the thickness of the film 50 is as thin as about 200 μm, the film 50 can be firmly attached even if there is a thickness tolerance. A sound-absorbing structure 1 having a stable strength can be obtained.

The embodiment described above can be modified as follows. In addition, the said embodiment and the following modified examples can be applied in combination with each other within a technically consistent range.
The hollow plate member 10 is not limited to the one composed of the core layer 20 and the skin layers 30 and 40 formed by folding the first sheet member 100 as described above. As the hollow plate material, for example, one having a shape as described in Japanese Patent No. 4368399 or Japanese Patent Application Laid-Open No. 2014-205341 may be used. In addition, layers corresponding to the skin layers 30 and 40 may be bonded to both surfaces of these hollow plate materials, or may be bonded to either one of the surfaces.

  The hollow plate material 10 is not limited to the one in which the first sheet material 100 is folded and formed to form the core layer 20, and the core layer may be formed by using a plurality of sheet materials. For example, the core layer may be formed by bending a belt-shaped sheet material at predetermined intervals and arranging the plurality of sheet materials together. In the case of this modified example, the bent portion in each sheet material constitutes the side wall portion of the cell.

  -The shape of the cell S in the hollow plate 10 is not limited to the hexagonal column shape. For example, the shape of the cell S may be a quadrangular prism shape or a cylindrical shape. Further, cells S having different shapes may be mixed. Furthermore, in the hollow plate member 10, not only when adjacent cells S are in contact with each other, an interval may be generated between two adjacent cells S. In addition, when the space | interval has produced between the cells S, not only the communication hole 15 which connects the inside and outside of the cell S but the communication hole which connects the inside and outside of the space between the cell S and the cell S is provided. It may be provided.

  The hollow plate 10 may be configured only by the core layer 20 and either or both of the skin layers 30 and 40 may be omitted. When the skin layer 30 is not joined, in the cell S1, the upper blocking wall 11 is constituted by the upper wall portion 21 having the two-layer structure, and in the cell S2, the upper blocking wall 11 is constituted by the upper wall portion 21 having the one-layer structure. .

In the sound absorbing structure 1 of the above embodiment, the upper blocking wall 11 has a multilayer structure, but may have a single layer structure.
In the hollow plate 10 of the above embodiment, the thickness of the upper blocking wall 11 that closes the cell S is thicker than the film 50 over the entire surface 10 a of the hollow plate 10. That is, the film 50 is thinner than all the blocking walls that block the ends of the cells S. Not only this but the part thinner than the film 50 may exist in a part of obstruction | occlusion wall.

  In the hollow plate 10 of the above embodiment, the thickness of the first sheet material 100 that forms the core layer 20 is about 0.3 mm, and the thickness of the second sheet material that forms the skin layers 30 and 40 is about 1.0 mm. It is. The thicknesses of the first sheet material 100 and the second sheet material are not limited to these thicknesses, and may be thinner or thicker than these thicknesses.

The skin layers 30 and 40 are not limited to be bonded to the core layer 20 by heat welding, and the skin layers 30 and 40 may be bonded to the core layer 20 with an adhesive or the like, for example.
-The hollow plate material 10 of the above embodiment may be in a state where the first sheet material 100 is heat-treated and softened in the folding process of the core layer 20, and the two-layer structure overlapping portion 131 is heat-welded and joined. Good. In this case, as shown in FIGS. 6 (a) and 6 (b), each overlapping portion 131 is thermally contracted at the same time as the thermal welding, and a pair of overlapping portions 131 partitioning the upper end of the first cell S1. A gap as the opening 24 is formed in the gap. Such an opening 24 is formed at the center of the cell S1 provided with the upper wall 21 having a two-layer structure. Therefore, when penetrating the communication hole 15 in the center of the cell S, the through-hole jig T may be passed through a portion where the upper wall portion 21 of the two-layer structure does not exist, and therefore the communication hole 15 can be easily formed. it can. The same applies when the skin layer 30 is omitted.

  -Another sheet material may be joined to the outer surface of the hollow plate 10 on the skin layer 40 side. The sheet material is not limited to a synthetic resin material, and may be, for example, a metal sheet (metal foil), a steel plate, paper, cloth, or the like. Moreover, you may comprise the skin layer 40 itself with a metal sheet (metal foil), paper, cloth, etc.

  -Another sheet material may be joined between the skin layer 30 and the film 50 in the hollow plate material 10. The sheet material is not limited to a synthetic resin material as long as the communication hole 15 can be formed. For example, a metal sheet (metal foil), paper, cloth, or the like may be used. The film 50 is fixed to the sheet material with an adhesive. The sheet material is also preferably fixed to the skin layer 30 with an adhesive.

  In the hollow plate 10, a plurality of communication holes 15 may be provided for one cell S. Further, the communication holes 15 may not be provided corresponding to all the cells S, and may be provided corresponding to a part of the cells S.

  -Application | coating of an adhesive agent may not be the aspect supplied on the surface 10a of the hollow plate material 10 by the application part C like the apparatus A. FIG. For example, a molten hot-melt adhesive may be applied with a coating roller or brush.

  -You may add the resin and additive which provide functionality to the thermoplastic resin which comprises the hollow board | plate material 10. As shown in FIG. For example, a flame retardant resin or additive may be added, or a deodorant or fragrance may be added.

The technical idea that can be grasped from the embodiment and the modified examples will be described.
(A) A sound absorbing structure in which a film is attached to the surface of a hollow plate material in which a plurality of cells are arranged in parallel, and a plurality of communication holes are formed on the surface on the film side to communicate the inside and outside of the cells. The hollow plate member includes a plurality of the cells defined by side walls extending in the thickness direction of the hollow plate member, and a blocking wall closing the end of the cell, and the film is attached to the surface of the blocking wall. The thickness of the film is smaller than the thickness of the blocking wall, and the communication hole penetrates the blocking wall and the film to communicate the inner area of the cell and the outer area of the film, The sound absorbing structure, wherein the film is bonded to the hollow plate member with an adhesive.

  (B) A method of manufacturing a sound absorbing structure in which a film is attached to the surface of a hollow plate material in which a plurality of cells are arranged in parallel, and a plurality of communication holes are formed on the surface on the film side to communicate the inside and outside of the cells. The hollow plate member includes a plurality of the cells defined by side walls extending in the thickness direction of the hollow plate member, and a blocking wall closing the end of the cell, and the film is a surface of the blocking wall. The thickness of the film is smaller than the thickness of the blocking wall, and the communication hole penetrates the blocking wall and the film to communicate the inner area of the cell and the outer area of the film. A method for producing a sound-absorbing structure, comprising: applying an adhesive to the hollow plate material and attaching the film; and forming the communication hole from the film side.

S ... cell, S1 ... first cell, S2 ... second cell, 1 ... sound absorbing structure, 10 ... hollow plate material, 11, upper closed wall, 12 ... lower closed wall, 15 ... communication hole, 20 ... core layer, 21 ... upper wall part, 22 ... lower wall part, 23 ... side wall part, 30, 40 ... skin layer, 50 ... film, 60 ... adhesive layer.

Claims (5)

A sound-absorbing structure in which a film is attached to the surface of a hollow plate,
The hollow plate member includes a plurality of cells defined by side walls extending in the thickness direction of the hollow plate member, and a blocking wall that closes an end of the cell,
The film is attached to the surface of the blocking wall,
The surface on the film side is provided with a plurality of communication holes penetrating the blocking wall and the film to communicate the inner area of the cell and the outer area of the film,
The thickness of the film is thinner than the thickness of the blocking wall,
The sound absorbing structure, wherein the film is bonded to the hollow plate member with an adhesive.   The sound absorbing structure according to claim 1, wherein the blocking wall has a multilayer structure.   The sound absorbing structure according to claim 1, wherein the film has a thickness of 10 to 500 μm.   The sound absorbing structure according to claim 1, wherein the adhesive is a hot-melt adhesive. The sound absorbing structure according to claim 4, wherein the adhesive is polyurethane reactive.