Sound Absorber with absorption bandwidth

Abstract

The present invention relates to a sound-absorbing device having a sound-absorbing bandwidth. The sound-absorbing device having a sound-absorbing bandwidth according to the present invention is characterized in that a plurality of resonators, each having a sound-absorbing surface having a predetermined area, a sound-absorbing hole formed on the sound-absorbing surface, and a sound-absorbing space provided on the rear side of the sound-absorbing hole, are arranged adjacently to form a unit cell, and the area of ​​the sound-absorbing surface of each resonator arranged adjacently is formed differently from each other, so that each resonator absorbs and removes noise of different frequencies.

Description

Technology Field

[0001] The present invention relates to a sound-absorbing device having a sound-absorbing bandwidth, and in particular, to a sound-absorbing device having a sound-absorbing bandwidth that eliminates noise of different frequencies by arranging noise-eliminating resonators adjacent to each other. Background Technology

[0002] Porous sound-absorbing materials have long been used for noise control and acoustic environment improvement. These materials possess numerous fine internal pores, and they exhibit a sound-absorbing effect as sound passes through these pores, resulting in energy loss due to friction. However, while this method is effective in the high-frequency range, it suffers from low absorption efficiency in the low-frequency range. Since low-frequency sounds have long wavelengths, physically very thick sound-absorbing materials are required to absorb them effectively. This hinders the efficient utilization of buildings and spaces and imposes structural constraints.

[0003] Furthermore, the sound absorption characteristics of porous sound-absorbing materials depend heavily on the physical properties of the material itself. This makes it difficult for designers to achieve desired sound absorption performance in specific frequency bands, and the absorption characteristics are limited depending on the material selection. In addition, porous materials are often susceptible to moisture or fire, which may restrict their use in environments requiring fire safety or moisture resistance. To address these issues, we propose a new sound-absorbing device utilizing resonance structures such as Helmholtz resonators. The problem to be solved

[0004] The present invention has been devised to solve the requirements described above, and aims to provide a sound-absorbing device having a sound-absorbing bandwidth that eliminates noise of different frequencies by arranging noise-eliminating resonators adjacent to each other. means of solving the problem

[0005] A sound-absorbing device having a sound-absorbing bandwidth according to an embodiment of the present invention is characterized in that a plurality of resonators, each having a sound-absorbing surface having a predetermined area, a sound-absorbing hole formed on the sound-absorbing surface, and a sound-absorbing space provided on the rear side of the sound-absorbing hole, are arranged adjacently to form a unit cell, and the area of ​​the sound-absorbing surface of each resonator arranged adjacently is formed differently from each other, so that each resonator absorbs and removes noise of different frequencies.

[0006] In addition, it is desirable that the sound-absorbing surface of each resonator forming the unit cell forms a single plane.

[0007] In addition, the above plane is rectangular, and it is preferable that the height of the sound-absorbing spaces of each resonator be the same.

[0008] In addition, it is preferable that each of the above resonators be formed of a metal, ceramic, carbon-based material, polymer compound, or a composite material comprising at least one of the above materials.

[0009] In addition, each of the above resonators is arranged in a predetermined row, and the area of ​​the sound-absorbing surface of the first resonator in the nth row (where n is a natural number) is larger than the area of ​​the sound-absorbing surface of the resonator in the last row of the nth row, and it is preferable that the area of ​​the sound-absorbing surface of the resonator in the last row of the nth row is larger than the area of ​​the sound-absorbing surface of the resonator in the first row of the n+1th row.

[0010] In addition, each of the above resonators is arranged to have a predetermined row, and it is preferable that the number of resonators arranged in the nth row (n is a natural number) is equal to or smaller than the number of resonators arranged in the n+1th row.

[0011] In addition, it is desirable that the diameter of the sound-absorbing holes of each of the above-mentioned resonators increases as the area of ​​the sound-absorbing surface decreases.

[0012] In addition, let the length of the guide tube connecting the sound-absorbing hole and the sound-absorbing space of each resonator be the neck length (l), and let the distance between the upper surface where the sound-absorbing surface of each resonator is located and the lower surface located opposite the upper surface be the height (H) of the resonator. It is preferable that the neck length and height of each resonator forming the unit cell are the same, and that the volume of the sound-absorbing space of each resonator is different.

[0013] In addition, when each of the above resonators is arranged to have a predetermined row, it is preferable that the distance between the top and bottom of the nth row (n is a natural number) is the same as the distance between the top and bottom of the n+1th row.

[0014] In addition, it is desirable that multiple unit cells are combined adjacently to form a unit module.

[0015] In addition, it is preferable that the sound-absorbing surface of each resonator forming the unit cell forms a single plane, and that the sound-absorbing surface of each unit cell forming the unit module forms a single plane.

[0016] In addition, the sound-absorbing surface of each resonator forming the unit cell forms a single plane, and when the distance between the upper surface where the sound-absorbing surface of each resonator forming the unit cell is located and the lower surface located opposite the upper surface is defined as the height (CH) of the unit cell, it is preferable that the unit module is a combination of unit cells having different unit cell heights.

[0017] In addition, it is preferable that the unit module has the unit cells arranged in a predetermined column, with multiple identical unit cells arranged in the nth column (where n is a natural number), and multiple unit cells different from the nth column arranged in the n+1th column.

[0018] Additionally, the unit module comprises the unit cells arranged in a predetermined column, and the unit module includes a central column positioned on the center side, a left column positioned to the left of the central column, and a right column positioned to the right of the central column, wherein the left column and the right column are symmetrical with respect to the central column.

[0019] In addition, it is desirable that the number of unit cells placed in each column of the left and right columns increases as they move further away from the center column. Effects of the invention

[0020] A sound-absorbing device having a sound-absorbing bandwidth according to the present invention provides the effect of removing noise of different frequencies, i.e., noise having a predetermined bandwidth, by arranging resonators that absorb and remove noise adjacent to each other.

[0021] Specifically, the present invention enables high sound absorption rates over a wide frequency band by arranging resonators of various sizes and shapes, such as Helmholtz resonators, on a plane.

[0022] Furthermore, conventional porous sound-absorbing panels require sound-absorbing material with a thickness greater than the wavelength of sound to effectively absorb low-frequency sounds, which increases volume and weight and imposes structural burdens and constraints on installation space. In contrast, the present invention allows the height of the resonator to be designed to be thinner than the wavelength of sound, thereby reducing volume and weight to achieve lightweight design, improving space utilization, and providing flexibility in architectural design. Additionally, by achieving a high sound absorption rate across a wide frequency band including not only high but also low frequencies, noise can be effectively controlled.

[0023] Furthermore, since the sound absorption characteristics of conventional porous sound-absorbing panels are determined by the physical properties of the material, it is difficult to freely adjust the desired sound absorption performance in a specific frequency band. Due to this limitation, designers face difficulties in implementing customized sound-absorbing panels that respond to various acoustic environments. However, the present invention allows the resonance frequency to be adjusted as desired by the designer by controlling the size of the resonator, the length of the neck, and the internal volume. This enables the optimization of sound absorption performance in a specific frequency band and allows for the production of customized sound-absorbing devices according to the usage environment and purpose. Moreover, the present invention can provide a sound-absorbing device capable of achieving sound absorption performance in a desired frequency band by adjusting the structural design of the resonator constituting the device.

[0024] Furthermore, the present invention can be utilized in various application fields, such as improving indoor acoustics in buildings, reducing noise in industrial sites, and controlling noise inside transportation vehicles. Since there are no restrictions on material selection, it provides the effect of imparting characteristics suitable for various environmental conditions through the flexibility of material selection, which allows for the selection of materials with excellent non-flammability and moisture resistance. Brief explanation of the drawing

[0025] FIG. 1 is a drawing illustrating a resonator employed in an embodiment of the present invention. FIG. 2 is a drawing illustrating an embodiment of a unit cell in which a plurality of resonators are arranged adjacently. Fig. 3 is a plan view of Fig. 2, FIG. 4 is a perspective view of FIG. 2 seen from a different angle. Figure 5 is a graph showing the sound absorption effect according to Figure 2. FIG. 6 is a drawing illustrating a unit module in which a plurality of unit cells are combined according to an embodiment of the present invention. Fig. 7 is a plan view of Fig. 6, Figure 8 is a graph showing the sound absorption effect according to Figure 6. FIG. 9 is a drawing illustrating a unit cell according to another embodiment of the present invention. Figure 10 is a graph showing the sound absorption effect according to Figure 9. FIG. 11 is a drawing illustrating a unit cell according to another embodiment of the present invention. Figure 12 is a graph showing the sound absorption effect according to Figure 11. FIG. 13 is a drawing illustrating a unit module according to another embodiment of the present invention. Fig. 14 is a plan view of Fig. 14. Specific details for implementing the invention

[0026] Hereinafter, various embodiments of the present invention are described in conjunction with the accompanying drawings. Since various embodiments of the present invention may be subject to various modifications and may have various forms, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the various embodiments of the present invention to specific forms, and it should be understood that they include all modifications and / or equivalents and substitutions that fall within the spirit and scope of the various embodiments of the present invention. In relation to the description of the drawings, similar reference numerals have been used for similar components.

[0027] Expressions such as "comprising" or "may comprise" that may be used in various embodiments of the present invention indicate the existence of the disclosed function, operation, or component, etc., and do not limit one or more additional functions, operations, or components, etc. Furthermore, in various embodiments of the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] When it is stated that a component is "combined" to another component, it should be understood that the component may be directly connected to the other component, or that a new component may exist between the component and the other component. On the other hand, when it is stated that a component is "directly combined" or "directly in contact" with another component, it should be understood that no new component exists between the component and the other component.

[0029] The terms used in the various embodiments of the present invention are used merely to describe specific embodiments and are not intended to limit specific embodiments of the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0030] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the various embodiments of the present invention pertain.

[0031] Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in the various embodiments of the present invention.

[0033] Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a drawing illustrating a resonator employed in an embodiment of the present invention, and FIG. 2 is a drawing illustrating an embodiment of a unit cell in which a plurality of resonators are arranged adjacently. FIG. 3 is a plan view of FIG. 2, FIG. 4 is a perspective view of FIG. 2 viewed from a different angle, and FIG. 5 is a graph showing the sound absorption effect according to FIG. 2. FIG. 6 is a drawing illustrating a unit module in which a plurality of unit cells are combined according to an embodiment of the present invention, FIG. 7 is a plan view of FIG. 6, and FIG. 8 is a graph showing the sound absorption effect according to FIG. 6. FIG. 9 is a drawing illustrating a unit cell according to another embodiment of the present invention, and FIG. 10 is a graph showing the sound absorption effect according to FIG. 9. FIG. 11 is a drawing illustrating a unit cell according to yet another embodiment of the present invention, and FIG. 12 is a graph showing the sound absorption effect according to FIG. 11. FIG. 13 is a drawing illustrating a unit module according to another embodiment of the present invention, and FIG. 14 is a plan view of FIG. 14.

[0035] A sound-absorbing device having a sound-absorbing bandwidth according to one embodiment of the present invention is related to acoustic engineering and noise removal technology, and forms a unit cell (200) by arranging a plurality of resonators (100) adjacently to absorb and remove noise of different frequencies.

[0037] 1. Resonator (100)

[0038] According to an embodiment of the present invention, as shown in FIG. 1, the resonator (100) includes a sound-absorbing surface (101), a sound-absorbing hole (102), and a sound-absorbing space (103).

[0039] The sound-absorbing surface (101) of the above-described resonator (100) has a predetermined area and refers to a surface where noise existing in space strikes. According to an embodiment of the present invention, the sound-absorbing surface (101) is formed flat. Of course, the sound-absorbing surface (101) is not limited to a flat surface. As shown in FIG. 1, the sound-absorbing surface (101) of the above-described resonator (100) is formed in a square shape, but the sound-absorbing surface (101) is not limited to a square shape, and the square shape should be understood as one embodiment.

[0040] The sound-absorbing hole (102) is formed in the sound-absorbing surface (101) to form a hole into which noise is introduced. According to the present embodiment, the sound-absorbing hole (102) is formed in a circular shape in the center of the sound-absorbing surface (101). According to the present embodiment, the diameter of the sound-absorbing hole (102) is formed differently depending on the area of ​​the sound-absorbing surface (101). In particular, as the area of ​​the sound-absorbing surface (101) decreases, the diameter of the sound-absorbing hole (102) is formed to be larger.

[0041] The sound-absorbing space (103) is a space provided on the rear side of the sound-absorbing hole (102). The sound-absorbing space (103) functions to reduce and eliminate noise through resonance and energy conversion. Specifically, noise reflected from the sound-absorbing surface (101) and noise to be emitted through the sound-absorbing space (103) and the sound-absorbing hole (102) are mutually canceled out and eliminated by resonance. According to the present embodiment, with reference to FIGS. 1 to 3, the sound-absorbing space (103) is formed in the shape of a cube or a rectangular prism, but its shape is not limited thereto.

[0042] According to an embodiment of the present invention, as shown in FIG. 1, the resonator (100) may be a Helmholtz resonator. Hereinafter, the operation of the Helmholtz resonator will be described first.

[0044] A Helmholtz resonator is composed of a sound-absorbing surface (101), a sound-absorbing hole (102), a sound-absorbing space (103), an induction tube (neck of the resonator) connecting the sound-absorbing hole (102) and the sound-absorbing space (103), and a boundary structure surrounding them. At this time, the effective impedance of the resonator sound-absorbing surface (101) is determined by the following physical parameters, as illustrated in FIG. 1. That is, the impedance of the resonator is determined by each factor f, r, l, h, d1, d2, D1, and D2. Here, ' ' is the frequency at which sound is incident, ' ' is the neck radius of the resonator, 'l' is the neck length of the resonator, ' ' is internal cavity depth, ' ' is the horizontal and vertical dimensions of the internal cavity, ' ' is the horizontal and vertical dimensions of the outer surface of the resonator, and ' ' is the effective impedance of the resonator.

[0046] Once the shape parameters and operating frequency of the Helmholtz resonator are determined, the effective impedance of the corresponding sound-absorbing surface (101) is uniquely determined. This can be obtained through experimental, numerical, or theoretical analysis approaches. Representative methods include, for instance, calculating the reflection coefficient from measurements of an impedance tube or reverberation chamber, calculating the sound field distribution through finite element or boundary element simulations, or estimating mass, elasticity, and loss components based on acoustic theory. Ultimately, regardless of which method is applied, once the shape and frequency are determined, the effective impedance of the resonator can be fixed to a specific value.

[0047] When multiple Helmholtz resonators with different resonant frequencies are arranged to enhance sound absorption across a wide frequency band, the total impedance It is expressed by the following mathematical formula 1 through the sum of the reciprocals of the individual resonator impedances as follows.

[0049] [Mathematical Formula 1]

[0050]

[0052] Here, N is the number of Helmholtz resonators, and represents the effective impedance of the nth Helmholtz resonator. Acoustic absorption coefficient It can be calculated using the reflection coefficient based on sound waves incident perpendicularly from the sound source. The characteristic impedance in air When the surface impedance is Z, the reflection coefficient R is expressed as Equation 2 as follows.

[0054] [Mathematical Formula 2]

[0055]

[0056] : Air density

[0057] : Speed ​​of sound in air

[0058] : Reflection coefficient

[0060] Sound absorption rate resulting from this is the ratio of energy lost relative to negative incident energy and can be expressed as Equation 3 as follows.

[0062] [Mathematical Formula 3]

[0063]

[0065] Sound absorption rate is frequency In addition, it is determined by the shape parameters of the Helmholtz resonators. One resonator has 7 shape parameters, and the total of 7N shape parameters are expressed by Equation 4 as follows.

[0067] [Mathematical Formula 4]

[0068]

[0070] Target frequency band The design problem for achieving uniform and high sound absorption performance involves adjusting the geometric parameters of multiple Helmholtz resonators to determine the sound absorption rate within the frequency range. It can be approached as an optimization problem that maximizes . Specifically, the target frequency band It is a problem of maximizing the lowest sound absorption rate, and can be expressed as Equation 5 below.

[0072] [Mathematical Formula 5]

[0073]

[0075] The lowest sound absorption rate in the target frequency band corresponds to the objective function, and the task of maximizing this is accomplished through numerical optimization techniques. Meanwhile, for design efficiency, the number of design variables can be reduced by adding a constraint that the 'l' and 'h' dimensions of Helmholtz resonators belonging to the same unit cell are identical. That is, the designer can design to optimize the sound absorption rate for a unit cell (200) composed of a set of resonators (100).

[0077] 2. Unit cell (200)

[0078] Referring to FIG. 2, according to an embodiment of the present invention, a plurality of resonators (100) are arranged adjacently to form a unit cell (200). In this embodiment, the area of ​​the sound-absorbing surface (101) of each resonator (100) arranged adjacently is formed differently from each other, so that each resonator (100) absorbs and removes noise of different frequencies. Accordingly, the sound-absorbing device according to an embodiment of the present invention provides the effect of removing noise having a predetermined bandwidth.

[0079] Referring to FIG. 4, the unit cell (200) comprises 12 resonators (111, 112, 113, 121, 122, 123, 124, 131, 132, 133, 134, 135). However, the number of resonators (100) constituting the unit cell (200) is not limited to this. Furthermore, according to the present embodiment, the sound-absorbing surface (101) of each resonator (100) constituting the unit cell (200) forms a single plane. That is, as illustrated in FIG. 2, the sound-absorbing surfaces (101) of each resonator (111, 112, 113, 121, 122, 123, 124, 131, 132, 133, 134, 135) are formed at the same height to form a single plane. According to the present embodiment, the upper surface (201) of the unit cell (200) forms a plane by the sound-absorbing surfaces (101) of each resonator (111, 112, 113, 121, 122, 123, 124, 131, 132, 133, 134, 135), and the plane is formed as a rectangle. However, the plane is not limited to a rectangle. For example, it may be formed as a polygon or an irregular shape.

[0080] In addition, the height of the sound-absorbing space (103) of each resonator (100) constituting the unit cell (200) is formed to be the same as that of each other. As shown in FIG. 2, the unit cell (200) according to one embodiment of the present invention is formed in an overall cuboid shape by having each resonator (111, 112, 113, 121, 122, 123, 124, 131, 132, 133, 134, 135) arranged adjacently, and the upper surface is flat, and the interior is divided into sound-absorbing spaces (103) by each resonator. The rear surface of the cuboid is finished by a separate cover. The shape of the cuboid may be a rectangular prism or a cube, but the overall shape of the unit cell is not limited to a cuboid.

[0081] Each resonator (100) constituting the unit cell (200) may be formed from a metal, ceramic, carbon-based material, polymer compound, or a composite material comprising at least one of the above materials. Of course, the material of the unit cell (200) is not limited thereto and may be made of various materials. Since the unit cell (200) is formed by combining the resonators (100), the material of the unit cell (200) may also be made of the same material as the resonator (100). For example, the unit cell (200) may be manufactured by methods such as injection molding or 3D printing, and may be made of various materials considering lightweighting, non-flammability, moisture resistance, etc.

[0083] According to an embodiment of the present invention, each resonator (100) forming the unit cell (200) is arranged in a predetermined row. The area of ​​the sound-absorbing surface (101) of the first resonator (100) in the nth row (n is a natural number) is formed to be larger than the area of ​​the sound-absorbing surface (101) of the last resonator (100) in the nth row, and the area of ​​the sound-absorbing surface (101) of the last resonator (100) in the nth row is formed to be larger than the area of ​​the sound-absorbing surface (101) of the first resonator (100) in the n+1th row. Additionally, the number of resonators arranged in the nth row (n is a natural number) may be formed to be equal to or smaller than the number of resonators arranged in the n+1th row.

[0084] Referring to FIGS. 3 and 4, a unit cell (200) according to one embodiment of the present invention illustrates a state in which resonators (100) are arranged in the first, second, and third rows. Three resonators (111, 112, 113) are arranged in the first row, four resonators (121, 122, 123, 124) are arranged in the second row, and five resonators (31, 132, 133, 134, 135) are arranged in the third row. At this time, the area of ​​the sound-absorbing surface (101) of the first resonator (111) among the resonators (111, 112, 113) arranged in the first row is formed to be larger than the area of ​​the sound-absorbing surface (101) of the last resonator (113) arranged in the first row. Additionally, the area of ​​the sound-absorbing surface (101) of the first resonator (121) among the resonators (121, 122, 123, 124) arranged in the second row is formed to be larger than the area of ​​the sound-absorbing surface (101) of the last resonator (124) arranged in the second row. This arrangement is applied in the same way to the third row. The area of ​​the sound-absorbing surface (101) of the first resonator (131) among the resonators (131, 132, 133, 134, 135) arranged in the third row is formed to be larger than the area of ​​the sound-absorbing surface (101) of the resonator (135) arranged at the end of the third row. At this time, the area of ​​the sound-absorbing surface (101) of the resonator (113) located at the end of the first row is larger than the area of ​​the sound-absorbing surface (101) of the first resonator (121) located in the second row, and the area of ​​the sound-absorbing surface (101) of the resonator (124) located at the end of the second row is larger than the area of ​​the sound-absorbing surface (101) of the first resonator (131) located in the third row.

[0085] Thus, according to one embodiment, the unit cell (200) may have resonators (100) arranged along a plurality of columns, and the area of ​​the sound-absorbing surface (101) of the first resonator (100) placed in each column may be formed larger than the area of ​​the sound-absorbing surface (101) of the last resonator (100). Also, at this time, the area of ​​the sound-absorbing surface (101) of the resonator (100) located at the end of the nth column may be formed larger than the area of ​​the sound-absorbing surface (101) of the first resonator (100) of the n+1th column. Additionally, as shown in FIG. 3, the number of resonators (100) may be arranged such that the number of resonators (100) increases as the number of columns increases. Of course, in another embodiment, when the resonators (100) are arranged in a plurality of columns, the same number of resonators (100) may be arranged in at least two columns. For example, as illustrated in FIG. 11, the number of resonators (100) placed in each column can be the same.

[0087] Additionally, according to the present embodiment, the length of the guide tube connecting the sound-absorbing hole (102) and the sound-absorbing space (103) of each resonator (100) is called the neck length (l), and the distance between the upper surface where the sound-absorbing surface (101) of each resonator (100) is located and the lower surface located opposite the upper surface is called the height (H) of the resonator. In this case, the neck length (l) and height (H) of each resonator forming the unit cell (200) are the same as each other, and the volume of the sound-absorbing space (103) of each resonator (100) is formed differently from each other. For example, as illustrated in FIGS. 2 to 4, when the unit cell (200) is composed of 12 resonators (111, 112, 113, 121, 122, 123, 124, 131, 132, 133, 134, 135), the neck lengths of each resonator (111, 112, 113, 121, 122, 123, 124, 131, 132, 133, 134, 135) are the same, and the volumes of the sound-absorbing spaces (103) can be formed differently. Of course, the resonators (100) constituting the unit cell (200) are not limited to 12, but can be formed in various numbers.

[0088] According to the present embodiment, when the unit cell (200) is arranged such that each resonator (100) has a predetermined row, the distance between the top and bottom of the nth row (n is a natural number) is formed to be the same as the distance between the top and bottom of the n+1th row. As shown in FIG. 3, the distance from the top to the bottom of the first row is the same as the distance from the top to the bottom of the second and third rows. However, in another embodiment, in the plurality of rows constituting the unit cell (200), the distance from the top to the bottom of each row may be different from each other, or at least some of the rows may be the same and the remaining rows may be formed differently.

[0089] As such, according to an embodiment of the present invention, the area of ​​the sound-absorbing surface (101) and the diameter of the sound-absorbing hole (102) of each of the plurality of resonators (100) forming the unit cell (200) are formed differently from each other, and the upper surface of the unit cell (200) is formed flat. Since different resonators (100) are combined with each other, they have an irregular shape, and the upper surface of the unit cell (200) is formed in a square shape, and the height of each resonator is made the same so that the unit cell (200) in which different resonators (100) are combined has the shape of a cuboid. Through this arrangement, the designer can easily design a sound-absorbing device having an optimal sound absorption rate while also facilitating the arrangement of irregularly shaped resonators (100).

[0090] Of course, the arrangement method of the unit cell (200) is not limited as described above. For example, the resonator (100) may not be arranged along a predetermined row but may be arranged randomly within a predetermined area.

[0092] 3. Unit module (300)

[0093] According to an embodiment of the present invention, a plurality of unit cells (200) may be adjacently combined to form a unit module (300). That is, the unit module (300) is a sound-absorbing device in which a plurality of unit cells (200) are arranged.

[0094] As illustrated in FIG. 6, the sound-absorbing surface (101) of each resonator (100) forming the unit cell (200) forms a single plane, and the sound-absorbing surface (201) of each unit cell (200) forming the unit module (300) forms a single plane. When a plurality of unit cells (200) are arranged adjacent to each other, the sound-absorbing surface (201) of each unit cell (200), which is the upper surface of each unit cell (200), is arranged at the same height so that the upper surface of the unit module (300) forms a single plane.

[0095] According to the present embodiment, the unit module (300) may be formed by combining multiple different unit cells (200) or by combining multiple identical unit cells (200). For example, referring to FIG. 7, FIG. 7 illustrates an example in which different unit cells (200) are combined. The unit cells (200) arranged in each column of FIG. 7 are identical unit cells (200), and the unit module (300) may be formed solely by the set of unit cells (200) arranged in each column, or the unit module (300) may be formed by arranging these identical unit cells (200) to have multiple columns. At this time, multiple resonators (100) having different sound-absorbing surfaces (101) are arranged in each unit cell (200).

[0096] Hereinafter, a case in which the above unit module (300) is formed by combining different unit cells (200) will be explained with reference to FIGS. 6 and FIGS. 7.

[0097] According to the present embodiment, when the distance between the upper surface where the sound-absorbing surface (101) of each resonator (100) forming the unit cell (200) is located and the lower surface located opposite the upper surface is called the height (CH) of the unit cell, the unit module (300) is formed by combining unit cells (210, 220, 230) having different heights. Referring to FIG. 6, the unit cell (210) positioned on the center side has a height of CH1, the height of the unit cell (220) adjacent to the unit cell (210) is CH2, and the height of the unit cell (230) adjacent to the unit cell (220) is given as CH3, and at this time, CH1, CH2, and CH3 are formed differently from each other. FIG. 6 discloses a unit module (300) in which three types of unit cells (210, 220, 230) are combined, but the types of unit cells (200) constituting the unit module (300) are not limited to three types.

[0098] According to an embodiment of the present invention, a plurality of unit cells (200) forming the unit module (300) are arranged in a predetermined column. A plurality of identical unit cells may be arranged in the nth column (n is a natural number), and a plurality of unit cells different from the nth column may be arranged in the n+1th column. Referring to FIGS. 6 and 7, when the column placed in the center column is called the first column, four identical unit cells (210) are arranged in the center column. Then, the second column, which is the first column among the right columns placed to the right of the first column, has eight identical unit cells (220R) arranged in it. Then, the third column placed to the right of the second column has 20 identical unit cells (230R) arranged in it. Thus, according to the present embodiment, the unit cells (200) arranged in each column may be formed differently from the unit cells (200) arranged in other columns while having identical unit cells (200) arranged in them. Meanwhile, in another embodiment, the unit cell (210) arranged in the first column and the unit cell (230) arranged in the third column may have the same unit cell (200) arranged therein.

[0099] And, as illustrated in FIG. 7, the unit module (300) includes a central column positioned on the center side, a left column positioned to the left of the central column, and a right column positioned to the right of the central column, and the left column and the right column may be formed symmetrically with respect to the central column. The unit cell (220L) of the left column closest to the central column and the unit cell (230L) adjacent to the unit cell (220L) are each positioned symmetrically with respect to the central column with respect to the unit cell (220R) of the right column closest to the central column and the unit cell (230R) adjacent to the unit cell (220R), respectively. Furthermore, the number of unit cells (200) positioned in each column of the left column and the right column is configured to increase as they move further away from the central column. As shown in FIG. 7, the unit cells (210) arranged in the central column are 4, the first column of the left and right columns has 8 unit cells (220R, 220L), and the second column of the left and right columns has 20 unit cells (230R, 230L), arranged so that the number of unit cells (200) increases as they move further away from the central column.

[0100] According to the present embodiment, when the unit module (300) is arranged such that each unit cell (200) has a predetermined column, the distance between the top and bottom of the nth column (n is a natural number) can be formed to be the same as the distance between the top and bottom of the n+1th column. In particular, according to the embodiment of the present invention, the unit module (300) can be formed in a rectangular or square shape. Furthermore, the unit module (300) according to the embodiment of the present invention provides the effect of facilitating an optimal design for absorbing noise of a desired bandwidth by the designer through a structure in which the unit cells (200) arranged in a plurality of columns have a symmetrical structure as described above and the number of unit cells (200) increases from the center toward the outside.

[0101] Of course, the above unit module (300) is not limited to arranging the unit cells (200) symmetrically as described above, or arranging them so that the number of unit cells (200) increases as they move away from the center. For example, in another embodiment, the unit module (300) may have the same unit cells (200) or different unit cells (200) arranged in a regular or irregular manner within a predetermined area.

[0103] Hereinafter, the operation of a sound-absorbing device having a sound-absorbing bandwidth according to the embodiment of the present invention according to the above-described configuration will be explained.

[0104] FIG. 5 shows the frequency sound absorption performance of the unit cell (200) according to FIG. 2. The resonator (100) according to FIG. 1 is capable of absorbing sound of a specific frequency, and the sound absorption device according to the present invention can be seen to exhibit sound absorption performance of approximately 90% or more in the band of approximately 400 Hz to 1000 Hz by having a plurality of resonators (100) arranged adjacent to each other.

[0105] FIG. 8 shows the frequency sound absorption performance of the unit module (300) according to FIG. 6. As shown in FIG. 8, it can be seen that sound absorption performance of approximately 90% or more is achieved in the band of approximately 700 Hz to 1650 Hz. This demonstrates that a wider range of sound absorption performance can be achieved by combining different types of unit cells (200), which means that the designer can select the desired frequency sound absorption band using a combination of unit cells (200).

[0107] 4. Other embodiments of the present invention

[0108] FIG. 9 illustrates another example of a unit cell (200). The unit cell (200) according to the embodiment of FIG. 9 is formed by arranging resonators (100) having different sound-absorbing surfaces (101) in a plurality of rows, and forming the number of resonators (100) placed in each row differently, so that the combined area of ​​the sound-absorbing surfaces (101) of each resonator (100) and the height (H) of the resonator (100) are formed larger than that of FIG. 2. The sound absorption performance according to FIG. 9 is illustrated in FIG. 10. As shown in FIG. 10, it can be confirmed that sound absorption performance of approximately 90% or more is achieved in the band of 200 Hz to 550 Hz.

[0109] Additionally, FIG. 11 illustrates another example of a unit cell (200). The unit cell (200) according to FIG. 11 is formed by arranging resonators (100) having different sound-absorbing surfaces (101) in multiple rows, with the number of resonators (100) placed in each row being equal. The sound absorption performance according to FIG. 11 is illustrated in FIG. 12. As shown in FIG. 12, it can be confirmed that sound absorption performance of approximately 90% or more is achieved in the band of 2000 Hz to 3300 Hz. Thus, the present invention can be designed to exhibit sound absorption performance in a desired frequency range through various embodiments.

[0110] Additionally, FIG. 13 illustrates another embodiment of a unit module (300). In FIG. 13, a plurality of unit cells (210, 220, 220) are arranged in each of the central column, the left column, and the right column, similar to the unit module (300) illustrated in FIG. 6. In each of the central column, the left column, and the right column, a plurality of identical unit cells (210, 220, 230) are arranged adjacently to form the unit module. However, according to FIG. 13, when the height of the unit cell (210) arranged on the central side is CH1, the height of the unit cell (220) adjacent to the unit cell (210) is CH2, and the height of the unit cell (230) adjacent to the unit cell (220) is CH3, the unit cells can be arranged such that their heights decrease sequentially as they move from the center of the unit module (300) toward the outside.

[0112] Thus, the sound-absorbing device having a sound-absorbing bandwidth according to the embodiment of the present invention combines a plurality of individual resonators (100), and the resonance frequency of the individual resonator (100) is determined according to the length (l) of the neck connecting the entrance of the sound-absorbing hole (102) and the sound-absorbing space (103), the diameter of the sound-absorbing hole (102), and the volume of the sound-absorbing space (103). Therefore, by numerically analyzing these variables through mathematical modeling or computer simulation, a sound-absorbing device in a predetermined frequency band can be provided, and the sound absorption efficiency in the predetermined frequency band can be optimized.

[0113] In addition, the unit cell (200) or unit module (300) according to the present embodiment can be manufactured as an integral or assembled unit, and various methods such as injection molding or 3D printing can be considered as manufacturing methods, thereby providing the effect of making the design and modification of the manufacturing easy and simple to manufacture.

[0114] In addition, since there are no limitations or restrictions on the materials, various materials with excellent fire resistance or moisture resistance can be selected and applied depending on the usage environment. Through this, a sound-absorbing device that achieves a high sound absorption rate over a wide frequency band can be provided.

[0116] Although the present invention has been described in detail with respect to preferred embodiments, the present invention is not limited to the above embodiments, and many variations may be provided within the scope of the present invention. Explanation of the symbols

[0117] 100... Resonator 101... Sound-absorbing surface 102... Sound absorption hole 103... Sound absorption space 111, 112, 113, 121, 122, 123, 124, 131, 132, 133, 134, 135... Resonator 200... Unit cell 201... Sound-absorbing surface of the unit cell 210, 220R, 220L, 230R, 230L ... unit cell 300...unit module

Claims

Claim 1 A sound-absorbing device having a sound-absorbing bandwidth, characterized in that a plurality of resonators each having a sound-absorbing surface having a predetermined area, a sound-absorbing hole formed on the sound-absorbing surface, and a sound-absorbing space provided on the rear side of the sound-absorbing hole are arranged adjacently to form a unit cell, the area of ​​the sound-absorbing surface of each resonator is formed differently, the volume of the sound-absorbing space of each resonator is formed differently, and the boundary formed by the adjacent resonators from the outermost perimeter of the unit cell to the inside is arranged in the shape of "a" or "eo," so that each resonator absorbs noise of different frequencies, the sound-absorbing surface of each resonator forming the unit cell forms a single plane, said plane is a rectangle, and the height of the sound-absorbing space of each resonator is the same, and inside the rectangle, each resonator is arranged in a plurality of rows, and a plurality of resonators are arranged in each row. Claim 2 delete Claim 3 delete Claim 4 A sound-absorbing device having a sound-absorbing bandwidth, characterized in that, in claim 1, each resonator is formed from a metal, ceramic, carbon-based material, polymer compound, or a composite material comprising at least one of the above materials. Claim 5 A sound-absorbing device having a sound-absorbing bandwidth according to claim 1, wherein when each resonator is arranged in a predetermined row, the area of ​​the sound-absorbing surface of the first resonator in the nth row (n is a natural number) is larger than the area of ​​the sound-absorbing surface of the last resonator in the nth row, and the area of ​​the sound-absorbing surface of the last resonator in the nth row is larger than the area of ​​the sound-absorbing surface of the first resonator in the n+1th row. Claim 6 A sound-absorbing device having a sound-absorbing bandwidth, characterized in that, in claim 1, when each resonator is arranged to have a predetermined row, the number of resonators arranged in the nth row (n is a natural number) is equal to or smaller than the number of resonators arranged in the n+1th row. Claim 7 A sound-absorbing device having a sound-absorbing bandwidth, characterized in that, in paragraph 4, the diameter of the sound-absorbing holes of each resonator increases as the area of ​​the sound-absorbing surface decreases. Claim 8 A sound-absorbing device having a sound-absorbing bandwidth according to claim 1, wherein the length of the guide tube connecting the sound-absorbing hole and the sound-absorbing space of each resonator is called the neck length (l), and the distance between the upper surface where the sound-absorbing surface of each resonator is located and the lower surface located opposite the upper surface is called the height (H) of the resonator, wherein the neck length and height of each resonator forming the unit cell are identical to each other, and the volume of the sound-absorbing space of each resonator is different from each other. Claim 9 A sound-absorbing device having a sound-absorbing bandwidth according to claim 6, characterized in that when each of the above resonators is arranged to have a predetermined row, the distance between the top and bottom of the nth row (n is a natural number) is the same as the distance between the top and bottom of the n+1th row. Claim 10 A sound-absorbing device having a sound-absorbing bandwidth according to claim 1, characterized in that a plurality of unit cells are adjacently combined to form a unit module. Claim 11 A sound-absorbing device having a sound-absorbing bandwidth, characterized in that, in claim 10, the sound-absorbing surface of each resonator forming the unit cell forms a single plane, and the sound-absorbing surface of each unit cell forming the unit module forms a single plane. Claim 12 In claim 10, the sound-absorbing surface of each resonator forming the unit cell forms a single plane, and when the distance between the upper surface where the sound-absorbing surface of each resonator forming the unit cell is located and the lower surface located opposite the upper surface is called the height (CH) of the unit cell, the unit module is characterized by being a combination of unit cells having different unit cell heights, thereby having a sound-absorbing device having a sound-absorbing bandwidth. Claim 13 In claim 10, the above unit module is characterized in that the unit cells are arranged in a predetermined column, a plurality of identical unit cells are arranged in the nth column (n is a natural number), and a plurality of unit cells different from the nth column are arranged in the n+1th column, thereby having a sound absorption bandwidth. Claim 14 A sound-absorbing device having a sound-absorbing bandwidth according to claim 10, wherein the unit module comprises a unit cell arranged in a predetermined column, and the unit module comprises a central column positioned on the center side, a left column positioned to the left of the central column, and a right column positioned to the right of the central column, wherein the left column and the right column are symmetrical with respect to the central column. Claim 15 A sound-absorbing device having a sound-absorbing bandwidth, characterized in that, in claim 14, the number of unit cells arranged in each column of the left column and right column increases as they move away from the central column.

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