Wall sound absorbing member

Abstract

To provide a wall sound absorbing member that is attached to a wall surface for use, has different resonance frequencies, and can exhibit uniform sound absorbing performance over a long distance along the wall surface.SOLUTION: A wall sound absorbing member 1 is a wall sound absorbing member that is attached to a wall surface for use. The wall sound absorbing member 1 has a plurality of resonant structures 4 (4a to 4d), each consisting of a cavity 2 (2a to 2d) formed continuously across the entire width and a slit 3 (3a to 3d) that connects the cavity 2 to the outside across the entire width, and the plurality of resonant structures 4 have at least two resonant frequencies.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sound absorbing member, and more particularly to a sound absorbing member for use on a wall by being attached to the wall surface. [Background technology]

[0002] In indoor spaces, noise caused by echoes of walking sounds, talking voices, etc. can be a hindrance to work or other tasks. To address this issue, sound-absorbing materials that can be attached to wall surfaces have been proposed.

[0003] For example, Patent Document 1 describes a sound-absorbing member having a plurality of cavities that differ from one another in at least one of shape and size, in which plate-like members that form the walls of the cavities included in the plurality of cavities have perforations that connect the inside and outside of the cavities, and the surface of the plate-like member includes a first region in which a plurality of perforations are formed, and a second region adjacent to the first region in which no perforations are formed (see Patent Document 1 (Claim 1, paragraphs 0018, 0022, Figure 1)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2023 / 013323 Summary of the Invention [Problem to be solved by the invention]

[0005] When a sound-absorbing material has a resonant structure with different resonant frequencies, the structure becomes complicated. Furthermore, when a conventional sound-absorbing material is attached to a wall, it is difficult to achieve uniform sound absorption performance over a long distance along the wall. An object of the present invention is to provide a wall sound-absorbing member that is attached to a wall surface and that has different resonance frequencies and can exhibit uniform sound-absorbing performance over a long distance along the wall surface. [Means for solving the problem]

[0006] The wall sound-absorbing member of the present invention, which has been able to solve the above-mentioned problems, is a wall sound-absorbing member that is attached to a wall surface for use, and is characterized in that the wall sound-absorbing member has a plurality of resonant structures each consisting of a cavity formed continuously across the entire width and a slit that connects the cavity to the outside across the entire width, and the plurality of resonant structures have at least two types of resonant frequencies. [Effects of the Invention]

[0007] The wall sound-absorbing member of the present invention has different resonance frequencies and can exhibit uniform sound-absorbing performance over a long distance along the wall surface. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing an example of a wall sound-absorbing member of the present invention. [Figure 2] FIG. 2 is a side view of the wall sound-absorbing member of FIG. [Figure 3] FIG. 2 is a front view of the wall sound-absorbing member of FIG. 1. [Figure 4] FIG. 1 is a close-up view of the resonant structure. [Figure 5] FIG. 10 is an enlarged view showing a modified example of the resonance structure. [Figure 6] FIG. 10 is an enlarged view showing a modified example of the resonance structure. [Figure 7] FIG. 10 is an enlarged view showing a modified example of the resonance structure. [Figure 8] FIG. 10 is an enlarged view showing a modified example of the resonance structure. [Figure 9] FIG. [Figure 10] FIG. 10 is a side view of the baseboard of FIG. [Figure 11] FIG. 10 is a front view of the baseboard of FIG. 9. [Figure 12] FIG. 10 is a side view of a modified baseboard. [Figure 13] FIG. 10 is a side view of a modified baseboard. [Figure 14] FIG. [Figure 15] FIG. 15 is a side view of the waist wall of FIG. 14. [Figure 16] FIG. [Figure 17] FIG. 17 is a side view of the handrail of FIG. 16. [Figure 18] FIG. 10 is a perspective view of a modified example of the handrail. [Figure 19] FIG. 19 is a side view of a modified example of the handrail of FIG. 18. [Figure 20] FIG. 1 is a cross-sectional view showing the dimensions of baseboard No. 1 of the embodiment. [Figure 21] FIG. 1 is a cross-sectional view showing the dimensions of baseboard No. 2 of the embodiment. [Figure 22] FIG. 10 is a cross-sectional view showing the dimensions of baseboard No. 3 of the embodiment. [Figure 23] FIG. 10 is a cross-sectional view showing the dimensions of baseboard No. 4 of the embodiment. [Figure 24] 1A and 1B are schematic diagrams showing the configuration of a reverberation box, in which (a) is a plan view and (b) is a cross-sectional view taken along line XX. [Figure 25] 10 is a graph showing the reverberation chamber sound absorption coefficient of the baseboard of the example. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Sound-absorbing wall materials] The wall sound absorbing member of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments.

[0010] FIG. 1 is a perspective view showing an example of a wall sound-absorbing member 1. FIG. 2 is a side view of the wall sound-absorbing member 1 of FIG. 1. FIG. 3 is a front view of the wall sound-absorbing member 1 of FIG. 1. FIG. 4 is an enlarged view of the resonant structure. In the drawings of this specification, the W direction is the width direction of the sound-absorbing member. The D direction is a direction perpendicular to the W direction and is the thickness direction (depth direction) of the sound-absorbing member. The H direction is a direction perpendicular to the W direction and D direction and is the height direction of the sound-absorbing member. The plane formed by the thickness direction D and the height direction H is the HD plane. In the present invention, the rear surface of the wall sound absorbing member refers to the mounting surface side that contacts the wall surface, and the front surface refers to the surface that faces the wall surface.

[0011] The sound-absorbing member for walls (hereinafter sometimes simply referred to as "sound-absorbing member") 1 of the present invention is a sound-absorbing member for walls that is attached to a wall surface. The sound-absorbing member 1 has a plurality of resonant structures 4 (resonant structures 4a to 4d in FIGS. 1 to 3) each of which is made up of a cavity 2 (cavities 2a to 2d in FIGS. 1 to 3) formed continuously across the entire width in the width direction and slits 3 (slits 3a to 3d in FIGS. 1 to 3) that connect the cavity to the outside across the entire width in the width direction, and each of the plurality of resonant structures 4 has at least two resonant frequencies.

[0012] In the sound-absorbing member 1, one slit 3 is formed for each cavity 2, and the resonant structure 4 composed of this one cavity 2 and one slit 3 becomes a so-called Helmholtz resonator. In this resonant structure 4, the air in the slit 3 vibrates at a resonant frequency, and sound is absorbed by friction with the inner wall. The sound-absorbing member 1 has multiple resonant structures 4, and each of the multiple resonant structures 4 has at least two resonant frequencies, so it can exert a sound-absorbing effect over a wide frequency band.

[0013] Furthermore, in the sound-absorbing member 1, the cavity 2 and the slits 3 are formed continuously across the entire width of the sound-absorbing member 1 in the width direction. Therefore, by arranging the sound-absorbing member so that it is continuous in the width direction, it is possible to achieve uniform sound-absorbing performance over a long distance along the wall surface. Furthermore, in the sound-absorbing member 1, the wall surrounding the cavity 2 and the wall in which the slits 3 are formed can be formed continuously in the width direction of the sound-absorbing member 1. Therefore, the sound-absorbing member 1 of the present invention can be molded as a single unit and can be easily manufactured.

[0014] In the cross section of the sound-absorbing member 1 in the height direction in the width direction (HD plane in the figure), the shape and dimensions of the cavity 2 and the shape and dimensions of the slit 3 are not particularly limited, and may be adjusted appropriately so as to obtain the desired resonance according to the resonant frequency of the resonant structure 4 that is configured.

[0015] In a cross section of the sound-absorbing member 1 in the height direction in the width direction (HD plane in the drawing), the shape of the slits 3 is not particularly limited as long as it can connect the cavity 2 with the outside of the sound-absorbing member 1. From the viewpoint of ease of molding the sound-absorbing member 1 and ease of designing and manufacturing the resonant frequency, it is preferable that the gap of the slits 3 be formed at a constant size, and that they be formed in a straight line from the cavity-side opening to the outside-side opening.

[0016] Since the sound-absorbing member 1 is used by being attached to a wall, the external opening of the slit is provided on the surface that is exposed when attached to the wall. In order to prevent dust from entering, it is preferable not to form a slit on the top surface of the sound-absorbing member (the surface that can be seen from above when attached to the wall). For example, in the sound-absorbing member 1 shown in Figures 1 to 3, the rear surface 5 is attached to a wall surface when used, so the external opening of the slit may be provided on a surface other than the rear surface 5 of the sound-absorbing member 1, and it is preferable that it be provided in a part that can be seen from the front when attached to a wall surface.

[0017] 1 to 3, when the cross section of the HD plane is elongated in the height direction, when the sound absorbing member 1 attached to a wall surface is viewed from the front, the area ratio of the total area of the exterior openings of the slits 3 visible from the front to the area of the sound absorbing member 1 visible from the front (frontal projected area) is preferably 5% or more, more preferably 7% or more, even more preferably 10% or more, and is preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. If the area ratio of the exterior openings is within the above range, sound waves can be easily captured, further improving sound absorption performance.

[0018] The sound-absorbing member 1 shown in Figures 1 to 3 has four resonant structures, namely, resonant structures 4a to 4d, each of which is formed by hollow portions 2a to 2d and slits 3a to 3d. However, the number of resonant structures 4 provided in the sound-absorbing member 1 is not particularly limited, and may be adjusted as appropriate to resonate according to the desired sound-absorbing performance. In the sound-absorbing member 1, the multiple resonant structures 4 have at least two resonant frequencies. That is, when the sound-absorbing member has two resonant structures, it has a first resonant structure and a second resonant structure having a resonant frequency different from the resonant frequency of the first resonant structure. When the sound-absorbing member has three or more resonant structures, it has at least a first resonant structure and a second resonant structure having a resonant frequency different from the resonant frequency of the first resonant structure. When the sound-absorbing member has three or more resonant structures, the resonant frequencies of the third or more resonant structures may be the same as or different from the resonant frequency of the first resonant structure or the resonant frequency of the second resonant structure. When the sound-absorbing member has three or more resonant structures, the multiple resonant structures may each have a different resonant frequency.

[0019] The resonant frequency of the resonant structure 4 may be selected appropriately depending on the noise to be absorbed. For example, to absorb human voices, the resonant frequency may be designed to be 400 Hz to 1500 Hz. To absorb walking sounds, the resonant frequency may be designed to be 1500 Hz to 4500 Hz. Therefore, the sound-absorbing member 1 is preferably configured to have at least one resonant structure with a resonant frequency of 400 Hz to 1500 Hz, or at least one resonant structure with a resonant frequency of 1500 Hz to 4500 Hz.

[0020] In the present invention, the resonant frequency of the resonant structure 4 is a theoretical value calculated by the following formula (1): In formula (1), f0 is the resonant frequency (Hz), c0 is the speed of sound in air (m / s), and V is the volume of the cavity (m 3 ), S: cross-sectional area of the slit (m), l: depth of the slit (m), δ: correction value.

[0021]

number

[0022] Furthermore, when the cross-sectional shape of the cavity 2 and slit 3 in the HD plane is rectangular, as shown in Figure 4, the theoretical values can also be calculated from the shapes of the cavity 2 and slit 3 using the following formula (2). In formula (2), f0 is the resonance frequency (Hz), c0 is the speed of sound in air (m / s), B is the height of the cavity (m), L is the depth of the cavity (m), b is the gap of the slit (m), l is the depth of the slit (m), and δ is the correction value. The dimensions of the cavity 2 and slit 3 are shown in Figure 4.

[0023]

number

[0024] In the sound-absorbing member 1 shown in Figures 1 to 3, the resonant structure 4 is composed of a cavity 2 having a rectangular cross-section in the HD plane and slits 3 extending parallel to the depth direction of the sound-absorbing member 1, but the resonant structure 4 is not limited to this configuration. Extending the slits 3 parallel to the thickness direction simplifies the structure and facilitates calculation and design of the resonant structure. The slits 3 may also be inclined relative to the thickness direction. By inclining the slits 3 in the thickness direction, the length of the slits 3 (the linear distance from the external opening to the cavity opening) can be maintained while shortening the distance from the outer surface of the sound-absorbing member 1 to the cavity 2. Therefore, in the sound-absorbing member 1 shown in Figures 1 to 3, the thickness of the sound-absorbing member 1 can be reduced by inclining the slits 3 in the thickness direction.

[0025] An example of a modified resonant structure will be described with reference to Figures 5 to 8. Figures 5 to 8 are enlarged views showing modified resonant structures. The resonant structure 4A shown in Figure 5 is composed of one cavity 2A and one slit 3A, and a partition plate 6 that divides the cavity 2A into two spaces is installed across the entire width of the sound-absorbing material. By installing the partition plate 6 in this way, two spaces are formed inside the cavity 2A, and each space forms a different resonant structure. This gives the resonant structure 4A two resonant frequencies, and it is thought that it can absorb a wide range of sounds. The partition plate 6 needs to be thin to achieve the desired resonant frequency, and therefore it is desirable to use a material that does not deform under its own weight, such as a hard resin.

[0026] The resonant structure 4B shown in Fig. 6, like the resonant structure 4A shown in Fig. 5, has a partition plate 6 that divides the cavity 2B into two spaces and is provided across the entire width of the sound-absorbing member, and like the resonant structure 4A shown in Fig. 5, has two resonant frequencies. Furthermore, in this resonant structure 4B, an extension 7 that extends up and down in the height direction H is formed at the tip of the partition plate 6. With this configuration, the presence of the extension 7 near the cavity-side opening of the slit 3B makes the slit 3B less noticeable on the outer surface of the sound-absorbing member. After the sound-absorbing member 1 is installed on a wall, the extension 7 makes it difficult to see inside through the slit 3B, improving the appearance and also preventing the intrusion of dirt and dust.

[0027] The resonant structure 4C shown in Figure 7 is composed of one cavity 2C and one slit 3C, and a neck portion 8 is formed in part of the cavity 2C across the entire width of the sound-absorbing member. By providing the neck portion 8 in this way, two spaces are formed inside the cavity 2C, and different resonant structures are formed in each space, giving the resonant structure 4 two resonant frequencies, allowing it to absorb a wide range of sounds and also shortening the height (H direction) dimension and making the sound-absorbing member 1 more compact. Furthermore, since a larger number of resonant structures can be provided without increasing the height dimension and keeping the same, it is possible to achieve sound absorption effects over a wider range of frequencies. 7, the neck portion 8 divides the cavity 2C into two spaces in the thickness direction D, but the neck portion 8 may be provided so as to divide the cavity 2C in the height direction. In this case, the dimension in the thickness direction (direction D) can be shortened, and the sound-absorbing member 1 can be made smaller.

[0028] The resonant structure 4D shown in Figure 8 is composed of one cavity 2D and one slit 3D, and multiple ridges 9 extending across the entire width of the sound-absorbing material are formed on the inner wall of the cavity 2D. The ridges 9 are thin-walled to be flexible. The ridges 9 vibrate in response to sound waves entering through the slits 3D, thereby further improving the sound-absorbing performance of the resonant structure 4D. The flexibility of the ridges 9 can be achieved by reducing their thickness or by using a more flexible material.

[0029] Furthermore, a fiber aggregate, nonwoven fabric, woven fabric, or the like may be disposed inside the cavity 2 of the sound-absorbing member 1. The fibers constituting the fiber aggregate, nonwoven fabric, or woven fabric are not particularly limited, and examples thereof include synthetic resin fibers such as polyester fibers and polyolefin fibers; inorganic fibers such as glass fibers and carbon fibers; and natural fibers such as wool. By disposing a fiber aggregate, nonwoven fabric, or woven fabric inside the cavity 2, the sound-absorbing performance can be further improved.

[0030] In the sound-absorbing member 1 shown in Figures 1 to 3, the cross-sectional shape in the height direction in the width direction of the sound-absorbing member 1 (cross-sectional shape in the HD plane) is a rectangle that is long in the height direction, but the cross-sectional shape of the sound-absorbing member 1 is not limited to this and may be semicircular, polygonal (triangle, pentagon, etc.), L-shaped, etc., and may be selected appropriately depending on the application. By using a rectangular shape, it is easier to create a larger resonant structure when placed along a wall surface. Furthermore, when manufactured by extrusion molding, the shape of the resin tends to be stable, making it easier to manufacture.

[0031] The width of the sound-absorbing member 1 is preferably 10 cm or more, more preferably 30 cm or more, and even more preferably 50 cm or more, and is preferably 250 cm or less, more preferably 200 cm or less, and even more preferably 150 cm or less. If the width is 10 cm or more, it is easy to install a sound-absorbing structure over a long distance along a wall surface, and the number of seams in the sound-absorbing member is reduced, resulting in more stable sound-absorbing performance. Furthermore, since the number of seams in the sound-absorbing member is reduced, the aesthetic appearance is improved. Furthermore, if the width is 250 cm or less, manufacturing is easy, handling is improved, and it is easier to construct a sound-absorbing structure along a wall surface. The height and thickness (depth) of the sound absorbing member 1 are not particularly limited, and may be adjusted appropriately depending on the application of the sound absorbing member 1.

[0032] It is preferable that the cross-sectional shape in the height direction in the width direction of the sound-absorbing member 1 (the cross-sectional shape in the HD plane when the height direction is H and the thickness direction is D) is constant over the entire width in the width direction. If the cross-sectional shape is constant over the entire width in the width direction, it becomes easier to manufacture the sound-absorbing member 1. It is also possible to use the sound-absorbing member 1 upside down.

[0033] (material) There are no particular limitations on the material that constitutes the sound-absorbing member 1, and resin, wood, metal, etc. can be used. From the standpoint of ease of production, the sound-absorbing member 1 is preferably formed from a resin composition that contains a resin component and a plasticizer.

[0034] The resin component may be used alone or in combination of two or more. Examples of the resin component include various synthetic resins such as vinyl chloride resins, vinyl acetate resins, ethylene-vinyl acetate copolymers, ABS (acrylnitrile-butadiene-styrene copolymers), polyolefin resins, polyurethane resins, amide resins, ester resins, and acrylic resins such as ethylene-methacrylate resins; various elastomers such as styrene-based elastomers; and rubber. Examples of vinyl chloride resins include vinyl chloride resins (homopolymers); copolymers containing vinyl chloride as a copolymerization component, such as vinyl chloride-vinyl acetate copolymers and ethylene-vinyl chloride copolymers. Examples of polyolefin resins include polypropylene resins and polyethylene resins. Vinyl chloride resins are particularly preferred as resin components because of their excellent flexibility, durability, and processability. Furthermore, vinyl chloride resins can exhibit excellent sound-absorbing properties without any problems. The synthetic resins may be either non-foamed or foamed.

[0035] When a vinyl chloride resin is used as the resin component, the content of the vinyl chloride resin in the resin component is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. It is also preferable to use only a vinyl chloride resin as the resin component.

[0036] The plasticizer may be used alone or in combination of two or more thereof. The plasticizer is not particularly limited, and examples thereof include dioctyl phthalate (DOP), diheptyl phthalate (DHP), diisononyl phthalate (DINP), trioctyl phosphate (TOP), triphenyl phosphate (TPP), dioctyl terephthalate (DOTP), dioctyl isophthalate (DOIP), and diisononyl cyclohexyl phthalate (DINCH).

[0037] The content of the plasticizer in the resin composition may be adjusted as appropriate depending on the desired mechanical strength of the sound-absorbing member. The content of the plasticizer in the resin composition is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and preferably 70 parts by mass or less, more preferably 60 parts by mass or less, per 100 parts by mass of the resin component. If the content of the plasticizer is 20 parts by mass or more, the flexibility of the sound-absorbing member 1 is increased, making it easier to apply the member along the shape of the wall surface, and improving application efficiency. Furthermore, if the content of the plasticizer is 70 parts by mass or less, the sound-absorbing member does not become too soft, resulting in good sound-absorbing effect, and bleeding of the plasticizer is suppressed.

[0038] The resin composition may contain a filler, if necessary. The filler may be used alone or in combination of two or more. The filler is preferably an inorganic filler. Examples of the inorganic filler include oxides, hydroxides, carbonates, chlorides, and silicates of inorganic or metallic elements. Specific examples include calcium oxide, barium carbonate, magnesium hydroxide, aluminum hydroxide, clay, talc, mica, calcium carbonate, silica sand, aluminum hydroxide, and calcium silicate. The calcium carbonate may be either heavy calcium carbonate or light calcium carbonate. Among these, calcium carbonate is preferably used as the inorganic filler from the viewpoints of processability and cost.

[0039] The filler can usually be used in powder form, and the volume average particle size can be appropriately set within the range of about 1 μm to 300 μm.

[0040] The content of the filler in the resin composition may be adjusted as appropriate depending on the desired hardness of the sound-absorbing member. When a filler is added, the content of the filler in the resin composition is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, per 100 parts by mass of the resin component.

[0041] The resin composition may contain other additives in addition to the plasticizer and filler. Examples of other additives include stabilizers, processing aids, antifungal agents, flame retardants, antioxidants, colorants, etc. When these additives are inorganic compounds, the content of such additives is also included in the content of the filler.

[0042] (Manufacturing method) The sound-absorbing material 1 can be obtained, for example, by extrusion molding the resin composition. Since the extrusion molded product is usually very long, the sound-absorbing material 1 can be obtained by cutting it to an appropriate size. After extrusion molding, a coating layer may be formed on the surface of the sound-absorbing material 1 by a coating treatment. By forming a coating layer, it is possible to impart hydrophilicity, water repellency, stain resistance, abrasion resistance, etc. to the sound-absorbing material 1.

[0043] For example, when manufacturing baseboards with sound-absorbing properties as sound-absorbing materials, the baseboards can be manufactured by thoroughly melt-kneading 100 parts by mass of vinyl chloride resin paste, 40 parts by mass of filler (calcium carbonate), 50 parts by mass of plasticizer (dioctyl phthalate (DOP)), 0.4 parts by mass of Pb-based stabilizer, and 0.9 parts by mass of pigment to prepare a resin composition, and then extruding this resin composition using a single-screw extruder.

[0044] (Application) The sound-absorbing member 1 can be suitably used as a wall sound-absorbing member that is attached to an indoor wall surface. There are no particular restrictions on the method for attaching the sound-absorbing member 1 to the wall surface. For example, the back surface 5 of the sound-absorbing member may be made flat and the member may be attached using adhesive, pressure-sensitive adhesive, nails, tacker needles, or the like, or an engaging portion may be provided on the back surface 5 of the sound-absorbing member 1 and the member may be attached using this engaging portion. It is preferable that the cavity 2 of the sound-absorbing member 1 attached to the wall surface be sealed on the side surface at the end in the width direction.

[0045] The sound-absorbing member 1 can be formed into a long length in the width direction, and therefore can be suitably used as, for example, a baseboard, a waist wall, a handrail, etc. In other words, the sound-absorbing member 1 can be suitably used as a baseboard with sound-absorbing properties, a waist wall with sound-absorbing properties, a handrail with sound-absorbing properties, etc.

[0046] Baseboards and waist walls are installed at the bottom of the wall. That is, the baseboards and waist walls are installed so that their undersides contact the floor and their backs contact the wall. In this invention, a baseboard refers to a piece with a height of 40 cm or less, and a waist wall refers to a piece with a height of more than 40 cm but not more than 120 cm. Note that sound-absorbing materials with a height of more than 120 cm can be used as wall components, and for example, it is possible to cover a wall from the top to the bottom with sound-absorbing materials. There is no particular limit to the height at which handrails can be installed, as long as they are installed at a height that is easy for users to grasp. The sound-absorbing materials can also be used in combination. For example, a baseboard, a waist wall, or a wall surface material can be installed on a wall, and a handrail can also be installed. By using them in combination in this way, a wall structure with an even greater sound-absorbing effect can be formed.

[0047] It is preferable that baseboards, waist walls, and wall components have slits formed in parts that are visible from the front when installed and attached to the wall.It is preferable that handrails have slits formed in at least one of parts that are visible from the front and parts that are visible from below when installed and attached to the wall.

[0048] (Example) Specific examples of the wall sound-absorbing member of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments.

[0049] (First embodiment: baseboard) Figures 9 to 11 show a baseboard 10 with sound absorbing properties as a first embodiment of a wall sound absorbing member. Figure 9 is a perspective view of the baseboard. Figure 10 is a side view of the baseboard of Figure 9. Figure 11 is a front view of the baseboard of Figure 9. Figures 12 and 13 are side views of modified baseboards.

[0050] The baseboard 10 has a plurality of resonant structures 14a to 14f, each of which is made up of a cavity 12a to 12f formed continuously across the entire width and a slit 13a to 13f connecting the cavity to the outside across the entire width.

[0051] The baseboard 10 has six cavities 12a, 12b, 12c, 12d, 12e, and 12f. Slits 13a, 13b, 13c, 13d, 13e, and 13f are formed in each of the cavities 12a to 12f. Resonant structure 14a is formed by cavity 12a and slit 13a. Similarly, resonant structure 14b is formed by cavity 12b and slit 13b, resonant structure 14c is formed by cavity 12c and slit 13c, resonant structure 14d is formed by cavity 12d and slit 13d, resonant structure 14e is formed by cavity 12e and slit 13e, and resonant structure 14f is formed by cavity 12f and slit 13f.

[0052] The resonant frequencies of the resonant structures 14a to 14f are 2000 Hz for resonant structure 14a, 2300 Hz for resonant structure 14b, 2600 Hz for resonant structure 14c, 3000 Hz for resonant structure 14d, 3500 Hz for resonant structure 14e, and 4000 Hz for resonant structure 14f. In the baseboard 10, the resonant structures 14a to 14f are arranged so that the resonant frequencies of the resonant structures increase from top to bottom in the height direction. The number of resonant structures 14 provided in the baseboard 10 and the resonant frequency of each resonant structure 14 may be adjusted appropriately depending on the desired sound absorption performance.

[0053] It is preferable that the baseboard 10 has at least one resonant structure with a resonant frequency of 1500 Hz to 4500 Hz. If the baseboard has a resonant structure with a resonant frequency in this range, it will have an excellent sound absorption effect against walking sounds.

[0054] The baseboard 10 preferably has at least a first resonant structure with a resonant frequency of 1500 Hz or more but less than 2500 Hz, a second resonant structure with a resonant frequency of 2500 Hz or more but less than 3500 Hz, and a third resonant structure with a resonant frequency of 3500 Hz or more but less than 4500 Hz. These resonant structures can provide a sound-absorbing effect over a wide frequency range from 1500 Hz to 4500 Hz, and can provide excellent sound-absorbing effects against various walking sounds.

[0055] In the baseboard 10, the cross-sectional shape of the hollow sections 12a to 12f in the height direction in the width direction (HD plane in the figure) is rectangular, and the slits 13a to 13f are formed in a straight line parallel to the depth direction of the baseboard 10 from the hollow section side opening to the external side opening so that the gap is constant.

[0056] The baseboard 10 is attached to a wall surface so that the back surface 15 faces the wall surface. As shown in Figures 9 to 11, the baseboard 10 has exterior openings of the slits 13a to 13f formed on the front surface of the baseboard 10. In the baseboard 10, the area ratio of the total area of the exterior openings of the slits 13 to the total area of the front surface is 15%.

[0057] The area ratio of the slit external openings formed on the front surface of the baseboard 10 may be adjusted as appropriate. When the slit external openings are formed on the front surface of the baseboard 10, the area ratio of the total area of the slit external openings to the total area of the front surface of the baseboard 10 is preferably 5 area% or more, more preferably 7 area% or more, and even more preferably 10 area% or more, and is preferably 40 area% or less, more preferably 30 area% or less, and even more preferably 20 area% or less.

[0058] The baseboard 10 has a rectangular cross-section in the height direction in the width direction (HD plane in the figure), which is constant across the entire width. Although the baseboard 10 shown in Figures 9 to 11 has a rectangular cross-section, the boundary between the front and top surfaces may be curved. In this case, when the baseboard is installed on a wall and viewed from the front, the visible portion is considered to be the front.

[0059] In the cross section of the baseboard 10 shown in Figures 9 to 11 in the height direction in the width direction (HD plane in the figures), the shape and dimensions of the hollow portions 12a to 12f and the shape and dimensions of the slits 13a to 13f are not particularly limited, and may be adjusted appropriately depending on the resonant frequency of the resonant structures 14a to 14f that are configured.

[0060] FIG. 12 is a side view of a modified baseboard 10. In this modified baseboard 10, slits 13a-13f are formed linearly from the cavity-side opening to the exterior-side opening, with the cavity-side openings positioned higher than the exterior-side openings. This configuration makes the openings less visible when viewed from above and prevents dust and other particles from entering the cavity 12 through the slits 13. By tilting the slits 13 relative to the thickness of the baseboard 10 in the height direction of the baseboard 10, the length of the slits 13 (the linear distance from the cavity-side opening to the exterior-side opening) can be maintained while shortening the distance from the front surface of the baseboard 10 to the cavity 12. This allows the thickness of the baseboard 10 to be reduced while maintaining a desired sound absorption frequency.

[0061] 13 is a side view of a modified baseboard 10. In this modified baseboard 10, the exterior openings of the slits 13a to 13f are formed on the front surface of the baseboard 10. The surface of the baseboard 10 on which the exterior openings of the slits 13a to 13f are formed is inclined downward relative to the back surface 15 of the baseboard 10. By forming it in this manner, sound waves other than those taken in through the slits 13a to 13f among the footstep sounds generated on the floor can be reflected downward, making it difficult for the footstep sounds to travel upward.

[0062] (Second embodiment: waist wall) 14 and 15 show a waist wall 20 having sound absorbing properties as a second embodiment of the wall sound absorbing member. Fig. 14 is a perspective view of the waist wall. Fig. 15 is a side view of the waist wall of Fig. 14.

[0063] The waist wall 20 has a plurality of resonant structures each consisting of a cavity 22 formed continuously across the entire width and a slit 23 connecting the cavity 22 to the outside across the entire width.

[0064] The waist wall 20 has 30 cavities 22. Each of the cavities 22 is formed with a slit 23. The cavities 22 and the slits 23 form a resonance structure.

[0065] The waist wall 20 has a shape similar to five baseboards 10 shown in FIG. 10 stacked vertically. Specifically, the waist wall 20 has six types of resonance structures, with resonance frequencies of 2000 Hz, 2300 Hz, 2600 Hz, 3000 Hz, 3500 Hz, and 4000 Hz, respectively, and five of each type of resonance structure. Thirty resonance structures are arranged in the waist wall 20 height direction. Starting from the top of the waist wall 20, the first resonance structure is numbered from the 30th resonance structure, and six types of resonance structures with different resonance frequencies are arranged from the 1st resonance structure to the 6th resonance structure. The resonance frequencies of the first resonance structure to the 6th resonance structure increase in stages. Similarly, six types of resonance structures with different resonance frequencies are arranged, from the 7th to 12th resonance structures, the 13th to 18th resonance structures, the 19th to 24th resonance structures, and the 25th to 30th resonance structures, and the resonance frequencies are arranged so that they increase in stages from top to bottom.

[0066] The number of resonant structures provided in the waist wall 20 and the resonant frequency of each resonant structure can be adjusted appropriately depending on the desired sound absorption performance. 14 and 15 show six types of resonant structures, each with five structures, but the resonant frequencies of all the resonant structures may be different, and the resonant frequencies may be arranged so that they increase in stages from top to bottom.

[0067] It is preferable that the waist wall 20 has at least one resonant structure with a resonant frequency of 1500 Hz to 4500 Hz. If the waist wall 20 has a resonant structure with a resonant frequency in this range, it will have an excellent sound absorption effect against walking sounds.

[0068] The waist wall 20 preferably has at least a first resonant structure with a resonant frequency of 1500 Hz or more but less than 2500 Hz, a second resonant structure with a resonant frequency of 2500 Hz or more but less than 3500 Hz, and a third resonant structure with a resonant frequency of 3500 Hz or more but less than 4500 Hz. If the waist wall 20 has these resonant structures, it can exhibit a sound absorbing effect over a wide frequency band in the range of 1500 Hz to 4500 Hz, and can exhibit an excellent sound absorbing effect against various walking sounds.

[0069] In the waist wall 20, the cross-sectional shape of the hollow portion 22 in the height direction in the width direction (HD plane in the figure) is rectangular, and the slits 23 are each formed in a straight line parallel to the depth direction of the waist wall 20 from the hollow portion side opening to the external side opening so that the gap is constant.

[0070] The waist wall 20 is used by being attached to a wall surface so that the back surface 25 faces the wall surface. As shown in Figures 14 and 15, the waist wall 20 has external openings of the slits 23 formed on the front surface of the waist wall 20. In the waist wall 20, the area ratio of the total area of the external openings of the slits 23 to the total area of the front surface is 15%.

[0071] The area ratio of the slit external openings formed on the front surface of the waist wall 20 may be adjusted as appropriate. When the slit external openings are formed on the front surface of the waist wall 20, the area ratio of the total area of the slit external openings to the total area of the front surface of the waist wall 20 is preferably 5 area% or more, more preferably 7 area% or more, and even more preferably 10 area% or more, and is preferably 40 area% or less, more preferably 30 area% or less, and even more preferably 20 area% or less.

[0072] The waist wall 20 has a rectangular cross-sectional shape in the height direction in the width direction (HD plane in the figure), which is constant across the entire width direction. Note that although the waist wall 20 shown in Figures 14 and 15 has a rectangular cross-sectional shape, the boundary between the front surface and the top surface may be curved. In this case, when the waist wall installed on a wall surface is viewed from the front, the visible part is considered to be the front surface.

[0073] 14 and 15, in a cross section taken along the height direction in the width direction (HD plane in the figures), the shape and dimensions of the cavity 22 and the slits 23 are not particularly limited and may be adjusted appropriately depending on the resonance frequency of the resulting resonance structure. As with the baseboard 10 described above, the slits 23 may be formed so that the gap is constant linearly from the cavity-side opening to the exterior-side opening, and the cavity-side opening may be positioned higher than the exterior-side opening.

[0074] (Third embodiment: handrail) 16 and 17 show a handrail 30 with sound absorbing properties as a third embodiment of the wall sound absorbing member. Fig. 16 is a perspective view of the handrail. Fig. 17 is a side view of the handrail in Fig. 16. Fig. 18 is a perspective view of a modified handrail. Fig. 19 is a side view of the modified handrail in Fig. 18.

[0075] By replacing an existing handrail, the handrail 30 can achieve sound absorption without the need for a separate sound-absorbing material. Furthermore, by using the handrail 30, which has sound absorption properties, in combination with baseboards or waist walls, which also have sound absorption properties, sound absorption properties can be imparted to both the lower and upper parts of the wall surface, resulting in a synergistic effect that can achieve a wide range of sound absorption effects.

[0076] The handrail 30 has multiple resonant structures 34 each consisting of a cavity 32 formed continuously across the entire width and a slit 33 connecting the cavity 32 to the outside across the entire width.

[0077] The handrail 30 has six cavities 32a, 32b, 32c, 32d, 32e, and 32f. Furthermore, cavities 32a to 32f each have one slit 33a, 33b, 33c, 33d, 33e, and 33f formed therein. Resonant structure 34a is formed by cavity 32a and slit 33a. Similarly, resonant structure 34b is formed by cavity 32b and slit 33b, resonant structure 34c is formed by cavity 32c and slit 33c, resonant structure 34d is formed by cavity 32d and slit 33d, resonant structure 34e is formed by cavity 32e and slit 33e, and resonant structure 34f is formed by cavity 32f and slit 33f.

[0078] The resonant frequencies of the resonant structures 34a to 34f are 2000 Hz for resonant structure 34a, 2300 Hz for resonant structure 34b, 2600 Hz for resonant structure 34c, 3000 Hz for resonant structure 34d, 3500 Hz for resonant structure 34e, and 4000 Hz for resonant structure 34f. On the handrail 30, the resonant structures 34a to 34f are arranged so that the resonant frequencies of the resonant structures increase from top to bottom in the height direction. The number of resonant structures 34 provided on the handrail 30 and the resonant frequency of each resonant structure 34 can be adjusted appropriately depending on the desired sound absorption performance.

[0079] It is preferable that the handrail 30 has at least one resonant structure with a resonant frequency of 1500 Hz to 4500 Hz. If the handrail 30 has a resonant structure with a resonant frequency in this range, it will have an excellent sound absorption effect against walking sounds.

[0080] The handrail 30 preferably has at least a first resonant structure with a resonant frequency of 1500 Hz or more but less than 2500 Hz, a second resonant structure with a resonant frequency of 2500 Hz or more but less than 3500 Hz, and a third resonant structure with a resonant frequency of 3500 Hz or more but less than 4500 Hz. If the handrail 30 has these resonant structures, it can exhibit a sound absorbing effect over a wide frequency band in the range of 1500 Hz to 4500 Hz, and can exhibit an excellent sound absorbing effect against various walking sounds.

[0081] In the handrail 30, in a cross section in the height direction in the width direction (HD plane in the figure), the cross-sectional shape of the hollow sections 32a to 32f is rectangular, and the slits 33a to 33f are each formed in a straight line parallel to the depth direction of the handrail 30 from the hollow section side opening to the external side opening so that the gap is constant.

[0082] The handrail 30 has a wall mounting portion 36 extending below the back surface 35, and is used by attaching this wall mounting portion 36 to a wall. As shown in Figures 16 and 17, the handrail 30 has exterior openings of the slits 33a to 33f formed on the front surface of the handrail 30. In the handrail 30, the area ratio of the total area of the exterior openings of the slits 33 to the total area of the front surface is 15%.

[0083] It is only necessary to appropriately adjust the area ratio of the slit external openings formed on the front surface of the handrail 30. When the slit external openings are formed on the front surface of the handrail 30, the area ratio of the total area of the slit external openings to the total area of the front surface of the handrail 30 is preferably 5 area% or more, more preferably 7 area% or more, even more preferably 10 area% or more, and is preferably 40 area% or less, more preferably 30 area% or less, even more preferably 20 area% or less.

[0084] The handrail 30 has an L-shaped cross section in the height direction in the width direction (HD plane in the figure), which is constant across the entire width direction. Note that the handrail 30 shown in Figures 16 and 17 has an L-shaped cross section, but the boundary between the front surface and the top surface and the boundary between the front surface and the bottom surface may be curved. In this case, when the handrail installed on a wall is viewed from the front, the visible part is considered to be the front.

[0085] In the handrail 30 shown in Figures 16 and 17, in the cross section in the height direction in the width direction (HD plane in the figure), the shape and dimensions of the hollow portions 32a to 32f and the shape and dimensions of the slits 33a to 33f are not particularly limited, and may be adjusted appropriately depending on the resonance frequency of the configured resonance structures 34a to 34f.

[0086] Furthermore, the cross-sectional shape of the handrail 30 in the height direction in the width direction (HD plane in the figure) is not particularly limited, and may be any shape that can be used as a handrail. Furthermore, in handrails with sound-absorbing properties, the external openings of the slits may be formed only on the front surface of the handrail, only on the underside of the handrail, or on both the front and underside of the handrail. Figure 18 is a perspective view of a modified handrail. Figure 19 is a side view of a modified handrail.

[0087] 18 and 19 has a wall mounting portion 36 that extends in the height direction, and a grip portion 37 that extends to the front side from the top of this wall mounting portion. Grip portion 37 has cavities 32a, 32b, and 32c that are formed continuously across the entire width in the width direction, and wall mounting portion 36 has cavities 32d, 32e, and 32f that are formed continuously across the entire width in the width direction.

[0088] Slits 33a, 33b, and 33c are formed in each of cavities 32a to 32c of gripping portion 37, and external openings of these slits 33a to 33c are formed in the underside of gripping portion 37. Slits 33d, 33e, and 33f are formed in each of cavities 32d to 32f of wall mounting portion 36, and external openings of these slits 33d to 33f are formed in the front side of wall mounting portion 36. The front side refers to the part that can be seen from the front when the handrail is attached to a wall, and the underside refers to the part that can be seen from below when the handrail is attached to a wall. [Example]

[0089] [Preparation of test specimens] Baseboards No. 1 to 4 having the cross-sectional shapes shown in Figures 20 to 23 were produced using a 3D printer (model "UP 300" manufactured by Tiertime). The cross-sectional shapes of baseboards No. 1 to 4 were constant across the entire width. ABS resin was used as the material. The baseboards shown in Figures 20 to 23 may be installed with the left side in the figure facing up, or the left side in the figure facing up, but it is preferable to install them with the left side in the figure facing up.

[0090] Baseboard No.1 Figure 20 shows a cross-sectional view of the HD plane of baseboard No. 1. The dimensions of the baseboard are 23 mm thick and 72 mm high. Baseboard No. 1 has four types of resonance structures, and the theoretical values of the resonance frequencies of each resonance structure are 2340 Hz, 3290 Hz, 3880 Hz, and 4180 Hz, from the left in Figure 20.

[0091] Baseboard No.2 Figure 21 shows a cross-sectional view of the HD plane of baseboard No. 2. The dimensions of the baseboard were 25 mm thick and 75 mm high. The test piece baseboard No. 2 had six resonance structures, and the theoretical resonance frequencies of each resonance structure were, from left to right in Figure 21, 2000 Hz, 2300 Hz, 2600 Hz, 3000 Hz, 3500 Hz, and 4000 Hz.

[0092] Baseboard No.3 Figure 22 shows a cross-sectional view of the HD plane of baseboard No. 3. The dimensions of the baseboard were 25 mm thick and 75 mm high. The test piece baseboard No. 3 had six resonance structures, and the theoretical resonance frequencies of each resonance structure were 1730 Hz, 2000 Hz, 2270 Hz, 2620 Hz, 3080 Hz, and 3600 Hz, from the left in Figure 22.

[0093] Baseboard No.4 Figure 23 shows a cross-sectional view of the HD plane of baseboard No. 4. The dimensions of the baseboard were 18 mm thick and 75 mm high. The test piece baseboard No. 4 had six resonance structures, and the theoretical resonance frequencies of each resonance structure were, from left to right in Figure 23, 2290 Hz, 2590 Hz, 2880 Hz, 3290 Hz, 3600 Hz, and 3960 Hz.

[0094] [Evaluation method] A reverberation box was created by changing the scale of the reverberation room to approximately 1 / 10, based on the reverberation room sound absorption coefficient measurement method of JIS A1409 (1998), and the sound absorption coefficient of wall sound-absorbing materials was measured using this reverberation box.

[0095] (reverberation box) FIG. 24 shows a schematic diagram illustrating the configuration of reverberation box 50. FIG. 24(a) is a plan view of the reverberation box, and FIG. 24(b) is a cross-sectional view of the reverberation box. Six sides of reverberation box 50 (front, back, right side, left side, bottom, and top) are constructed from acrylic panels (20 mm thick). The interior dimensions are width W1 of 610 mm, depth D1 of 590 mm, and height H1 of 600 mm. A sound source 51 was installed facing the corner between the front and left sides of reverberation chamber 50, and four sound level meters 52a, 52b, 52c, and 52d were installed inside the reverberation box. Diffusers 53a, 53b, 53c, and 53d were installed on each of the front, back, right, and left sides of the reverberation box to homogenize the sound field inside the box. The sound level meters were installed at least λ / 2 apart (λ: wavelength of the sound at the center frequency of the frequency band being measured). The test piece 54 was placed in the center of the bottom surface of the reverberation chamber.

[0096] (measuring reverberation time) Regarding the measurement frequencies, measurements were performed in 1 / 3 octave bands of 500 Hz, 630 Hz, 800 Hz, 1000 Hz, 1250 Hz, 1600 Hz, 2000 Hz, 2500 Hz, 3150 Hz, 4000 Hz, 5000 Hz, 6300 Hz, 8000 Hz, 10000 Hz, and 12500 Hz. In the measurement, after the sound source was stopped, the reverberation was measured for 90 seconds and a decay curve was created. The reverberation time was measured by fitting a straight line to the range from -5dB to -35dB after the sound source was stopped.

[0097] (Measurement procedure) The baseboards to be measured were three 10cm wide baseboards and one 8cm wide baseboard, arranged widthwise for a total width of 38cm, and four rows arranged heightwise. The sides of the entire lined-up baseboards were then covered and fixed with an aluminum frame to form the test specimen. The total area of the front of the test specimen for baseboard No. 1 was 0.10944m 2 The total area of the front of the test pieces of baseboard No. 2 to 4 is 0.11400 m 2 is. In the measurement, first, the test piece was placed in the center of the underside of the reverberation chamber with the back side of the baseboard (the side without the slits) facing up, and the reverberation time was measured, which was used as the blank value. Next, the test piece was placed in the center of the underside of the reverberation chamber with the front side (the side with the slits) facing up, and the reverberation time was measured, which was used as the measured value. The sound absorption coefficient at each frequency was then calculated from the blank value and the measured value. Note that in order to reduce measurement errors due to air vibrations in the reverberation chamber, the test piece was placed and covered with an acrylic plate on top, and then measurements were taken 90 seconds later.

[0098] The reverberation chamber sound absorption coefficients of baseboards No. 1 to 4 are shown in Figure 25. From the graph, it can be seen that all of baseboards No. 1 to 4 absorb sound at frequencies between 2000 Hz and 4000 Hz. Furthermore, by comparing the sound absorption coefficients of baseboards No. 1 and No. 2, it can be seen that increasing the number of resonant structures improves the sound absorption coefficient. Note that there are some areas where the sound absorption coefficient falls below 0 below 1600 Hz, but this is thought to be due to the fact that the reverberation box is a scale model, making it difficult to properly measure low frequencies. [Industrial Applicability]

[0099] The wall sound-absorbing member of the present invention can be suitably used as a wall sound-absorbing member that is attached to an indoor wall surface. Specifically, the wall sound-absorbing member can be used as a baseboard with sound-absorbing performance, a waist wall with sound-absorbing performance, a handrail with sound-absorbing performance, etc. The wall sound-absorbing member of the present invention can exhibit additional sound-absorbing effects simply by replacing the baseboard, waist wall, and handrail that have been conventionally used, thereby simplifying installation and enabling space savings. [Explanation of symbols]

[0100] 1: sound absorbing material, 2: cavity, 3: slit, 4: sound absorbing structure, 5: back, 10: baseboard, 12: cavity, 13: slit, 14: sound absorbing structure, 15: back, 20: waist wall, 22: cavity, 23: slit, 24: sound absorbing structure, 25: back, 30: handrail, 32: cavity, 33: slit, 34: sound absorbing structure, 35: back,

Claims

1. A sound-absorbing member for a wall that is attached to a wall surface and used, The wall sound-absorbing member has a plurality of resonant structures each having a cavity formed continuously across the entire width in the width direction and a slit communicating the cavity with the outside across the entire width in the width direction, A sound-absorbing member for a wall, wherein the plurality of resonant structures have at least two kinds of resonant frequencies.

2. 2. The sound-absorbing member for wall surfaces according to claim 1, wherein the cross-sectional shape in the height direction is constant across the entire width of the sound-absorbing member for wall surfaces.

3. 2. The sound-absorbing wall member according to claim 1, wherein the sound-absorbing wall member has at least one resonant structure having a resonant frequency of 1500 Hz to 4500 Hz.

4. 2. The sound-absorbing member for walls according to claim 1, which is used as a baseboard or a waist wall.

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