Sound absorption structure, manufacturing method of sound absorption structure and sound absorption plate

Abstract

The invention relates to a sound absorption structure which is provided with a first structural layer and a second structural layer. A plurality of through holes are formed in the first structural layer, the first structural layer and the second structural layer are stacked to form a plurality of cavities, and the cavities and the corresponding through holes form a plurality of sound absorption units; in the direction perpendicular to the first direction, the ratios of the cross sectional areas of the through holes (40) of at least part of the sound absorption units to the cross sectional areas of the corresponding cavities are different, so that the sound waves with different frequencies can be effectively absorbed by the plurality of sound absorption units; the through holes with different cross-sectional areas or the cavities with different cross-sectional areas are arranged in the direction perpendicular to the first direction, so that broadband sound waves in a larger range can be absorbed by sound absorption.

Description

Technical Field

[0001] The present invention relates to the technical field of noise reduction, and in particular to a sound absorbing structure, a method for manufacturing the sound absorbing structure, and a sound absorbing board. Background Art

[0002] With the development of technology, vehicles, trains, house designs, office spaces, etc. have higher requirements for noise control. Among them, noise has always been regarded as a major problem in noise control due to the particularity of its sound wave wavelength. In the prior art, noise control mainly uses sound-absorbing materials with holes and sound-absorbing structures made of non-hole partitions to achieve sound absorption, but it can only effectively absorb broadband sound waves in a smaller range. When the noise contains broadband sound waves in a larger range, the existing sound absorption cannot effectively absorb broadband sound waves of multiple different frequencies. Summary of the invention

[0003] An embodiment of the present application provides a sound absorbing structure.

[0004] The sound absorbing structure provided in the embodiment of the present application includes a first structural layer and a second structural layer; the first structural layer has a plurality of through holes, and the first structural layer is suitable for absorbing sound waves; along a first direction, the first structural layer and the second structural layer are stacked, and the second structural layer is suitable for enclosing a plurality of cavities with the first structural layer; the through holes and the cavities are correspondingly connected to form a plurality of sound absorbing units;

[0005] Vertically to the first direction, ratios of the cross-sectional areas of the through holes of at least some of the sound absorbing units to the cross-sectional area of ​​the cavity are different.

[0006] In some embodiments, in a direction perpendicular to the first direction, the cross-sectional areas of the plurality of cavities are the same, and the cross-sectional areas of at least some of the through holes are different; or

[0007] The cross-sectional areas of the plurality of through holes are the same, and the cross-sectional areas of at least some of the cavities are different.

[0008] In some embodiments, the second structural layer is provided with a plurality of cavities penetrating the second structural layer along the first direction, and the plurality of cavities correspond to the plurality of through holes and are suitable for enclosing a plurality of cavities with the first structural layer.

[0009] In some embodiments, there are a plurality of the first structural layer and a plurality of the second structural layers, and the number of the first structural layers is equal to the number of the second structural layers; and / or

[0010] The number of the first structural layers is one greater than the number of the second structural layers;

[0011] The first structure layers and the second structure layers are alternately stacked along the first direction.

[0012] In some implementations, in the first direction, cross-sectional areas of corresponding through holes of at least some of the first structural layers are different.

[0013] In some embodiments, a third structural layer is further included, wherein the third structural layer is connected to a side of the second structural layer away from the first structural layer, so as to close the cavity.

[0014] In some embodiments, an orthographic projection of the through hole on a projection plane perpendicular to the first direction is located within an orthographic projection of the cavity on the projection plane.

[0015] In some embodiments, in a direction perpendicular to the first direction, the cross-section of the cavity is a quadrilateral; and / or the cross-section of the through hole is a circle.

[0016] In certain embodiments, the first connecting layer and the second connecting layer are connected by ultrasonic welding, brazing or bonding.

[0017] In some embodiments, the first structural layer is a sound absorbing metamaterial; and / or the second structural layer is a sound absorbing metamaterial.

[0018] The present application also provides a method for manufacturing a sound absorbing structure, the manufacturing scheme comprising: obtaining a first structural layer, forming a plurality of through holes in the first structural layer, the first structural layer being suitable for absorbing sound waves;

[0019] Obtain a second structural layer, and stack and connect the first structural layer and the second structural layer along a first direction to enclose a plurality of cavities;

[0020] The through holes and the cavity are connected to each other to form a plurality of sound absorbing units. Perpendicular to the first direction, the ratio of the cross-sectional area of ​​the through holes of at least some of the sound absorbing units to the cross-sectional area of ​​the cavity is different.

[0021] In some embodiments, the stacking and connecting the first structural layer and the second structural layer to enclose a plurality of cavities includes: forming a plurality of cavities in the second structural layer corresponding to the plurality of through holes.

[0022] In some embodiments, forming a plurality of through holes in the first structural layer includes: obtaining a cross-sectional area of ​​each of the through holes;

[0023] The cross-sectional area of ​​each of the through holes is obtained based on the target sound absorption efficiency, the target sound absorption frequency, the preset values ​​of the cross-sectional areas of the multiple cavities perpendicular to the first direction, the first thickness of the first structural layer in the first direction, the second thickness of the second structural layer perpendicular to the first direction, and a preset model.

[0024] In some embodiments, the target sound absorption efficiency ranges from [0.3-0.9].

[0025] In some embodiments, the target sound absorption frequency ranges from [500-1500 Hz].

[0026] In certain embodiments, the cross-sectional areas of the plurality of cavities in a direction perpendicular to the first direction are the same.

[0027] In certain embodiments, the pre-set model is a matrix laboratory.

[0028] The present application also provides a sound absorbing plate, which includes the sound absorbing structure provided by the present application and / or a method for manufacturing the sound absorbing structure provided by the present application.

[0029] The sound absorption of the present application stacks the first structural layer and the second structural layer so that the second structural layer forms a plurality of cavities with through holes. Since the ratio of the cross-sectional area of ​​the cavity to the cross-sectional area of ​​the through hole determines the resonance frequency of the cavity; when the cross-sectional area of ​​the cavity is the same, the cross-sectional areas of the plurality of through holes are different; and / or when the cross-sectional area of ​​the through hole is the same, the cross-sectional areas of the plurality of cavities are different, so that the ratio of the cross-sectional area of ​​the cavity of the plurality of sound absorption units to the cross-sectional area of ​​the through hole is different, and the plurality of sound absorption units with different ratios can effectively absorb sound waves of different frequencies, that is, by setting through holes of different cross-sectional areas or cavities of different cross-sectional areas, the sound absorption structure of the present application can absorb a wider range of broadband sound waves.

[0030] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0032] Figure 1 An exploded view of a sound absorbing structure according to some embodiments of the present application;

[0033] Figure 2 is an overall diagram of a noise reduction device according to certain embodiments of the present application;

[0034] Figure 3 is an exploded view of a sound absorbing structure according to certain embodiments of the present application;

[0035] Figure 4 is a cross-sectional view of a sound absorbing structure according to some embodiments of the present application.

[0036] Description of main component symbols:

[0037] 10-first structural layer; 100-first sub-structural layer; 200-second sub-structural layer; 300-third sub-structural layer; 400-fourth sub-structural layer;

[0038] 20-second structural layer; 1000-fifth sub-structural layer; 2000-sixth sub-structural layer; 3000-seventh sub-structural layer;

[0039] 30- third structural layer;

[0040] 40-through hole; 101-first through hole; 201-second through hole; 301-third through hole; 401-fourth through hole;

[0041] 50-cavity; 1001-first cavity; 2001-second cavity; 3001-third cavity; b1-first thickness; d1-second thickness. DETAILED DESCRIPTION

[0042] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and cannot be understood as limiting the embodiments of the present application.

[0043] In the description of the present application, it should be understood that the terms "thickness", "upper", "top", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0044] The sound absorption structure currently used in the industry generally adopts perforated sound absorption panels and non-perforated partitions alternately stacked and widely used. This sound absorption structure can only effectively absorb a small range of broadband sound waves. When the noise contains a large range of broadband sound waves, the existing sound absorption structure cannot effectively absorb a variety of broadband sound waves of different frequencies.

[0045] The present application provides a sound absorbing structure comprising a first structural layer (10) and a second structural layer (20); the first structural layer (10) has a plurality of through holes (40); along a first direction X, the first structural layer (10) and the second structural layer (20) are stacked, the second structural layer (20) can form a cavity (50) with the first structural layer (10), the through holes (40) and the cavity (50) are correspondingly connected to form a plurality of sound absorbing units; perpendicular to the first direction X, the ratio of the cross-sectional area of ​​the through holes (40) of at least some of the sound absorbing units to the cross-sectional area of ​​the cavity (50) is different. When the cross-sectional areas of the cavities (50) perpendicular to the first direction X are the same, the cross-sectional areas of at least some of the through holes (40) perpendicular to the first direction X are different, and / or when the cross-sectional areas of the through holes (40) perpendicular to the first direction X are the same, the cross-sectional areas of at least some of the cavities (50) in the second direction are different. The first structural layer (10) and the second structural layer (20) are stacked to form a plurality of sound absorbing units. The volume of the cavity and the volume of the through hole corresponding to the cavity determine the resonance frequency of the cavity. In this sound absorbing structure, the first structural layer (10) and the second structural layer (20) can be stacked on the premise that the thickness of the first structural layer (10) and the second structural layer (20) in the first direction X is the same everywhere, that is, the first structural layer (10) and the second structural layer (20) are both made of materials with uniform thickness; that is, the difference in volume of each through hole (40) on the same first structural layer (10) is reflected in the difference in cross-sectional area, and the difference in volume of each cavity on each second structural layer (20) is also reflected in the difference in cross-sectional area. By setting the volume of at least part of the through holes (40) or at least part of the volume of the cavity (50) to different sizes, the resonance frequencies of the multiple cavities can be different, and the cavities with different resonance frequencies can effectively absorb sound waves of different frequencies, that is, by setting the cross-sectional areas of the through holes perpendicular to the first direction X to different sizes or setting the cross-sectional areas of the cavities to different sizes, the sound absorption structure of the present application can absorb a wider range of broadband sound waves. The sound absorption structure of the present application is described in detail below through specific embodiments.

[0046] In some embodiments, when the sound absorbing structure is single-sided sound absorbing, the number of the first structural layer 10 is equal to the number of the second structural layer 20. Figure 1In the single-sided sound absorption structure, the first structural layer 10 includes a fourth substructure layer 400, the second structural layer 20 includes a seventh substructure layer 3000, the fourth substructure layer 400 includes a plurality of fourth through holes 401, and the seventh substructure layer 3000 includes a plurality of third cavities 3001. When the sound absorption structure is single-sided sound absorption, the side of the second structural layer (20) away from the first structural layer (10) can be fixed to other fixed objects, such as a wall, a bottom plate, etc. The side of the seventh substructure layer 3000 opposite to the fourth substructure layer 400 can also be closed, and the third cavity 3001 is not penetrated in the first direction; for example, the side of the seventh substructure layer 3000 opposite to the fourth substructure layer 400 can be closed with the third structural layer 30. The third structural layer 30 can be a soft material, or a material such as wood or metal, or it can be the same as the material of the seventh substructure layer 3000 or the fourth substructure layer 400, which is not limited here. The single-sided sound absorption structure can also be made by alternately stacking a plurality of first structural layers (10) and a plurality of second structural layers (20). The number of the first structural layers (10) and the second structural layers (20) is determined according to the actual target sound absorption efficiency and the target sound absorption frequency, and is not limited here.

[0047] Furthermore, in order to enable the sound absorbing structure to achieve effective sound absorption in a larger frequency range, in certain embodiments, the cross-sectional areas of the multiple through holes (40) of the first structural layer (10) perpendicular to the first direction X can be calculated by a calculation model, and the first structural layer (10) is prepared according to the calculated cross-sectional areas of the multiple through holes (40) perpendicular to the first direction X. Specifically, the target sound absorption efficiency and the target sound absorption frequency range of the sound absorbing structure are first confirmed, the thickness of the first structural layer (10) and the second structural layer (20) in the first direction X, and the cross-sectional area of ​​the cavity (50) perpendicular to the first direction X are obtained, and the cross-sectional areas of the multiple through holes (40) of the first structural layer (10) perpendicular to the first direction X are calculated by a calculation model.

[0048] The target sound absorption frequency range is the frequency range in which the sound absorption structure of the present application can effectively absorb sound. The target sound absorption frequency range of the present application can be set to 500HZ-1500HZ, and can also be set to other frequency ranges, which are not limited here. The value range of the target sound absorption efficiency is 0-1. When the target sound absorption efficiency is 0, the low-frequency sound absorption metamaterial structure cannot absorb sound. When the target sound absorption efficiency is 1, all sound waves within the target sound absorption frequency range can be absorbed by the low-frequency sound absorption metamaterial structure. In the actual application of low-frequency sound absorption metamaterial structures, the target sound absorption efficiency in the range of 0.5-1 is usually regarded as effective sound absorption. Of course, the value range of effective sound absorption can also be adjusted according to actual conditions. The formula of the calculation model is:

[0049] A

[0050] =F(f,r 11,r 12 ,...,r 1n ,r 21 ,r 22 ,..r 2m ,...r l1 ,.r le ,d 1 ,d 2 ,d 3 ,...,d k ,a 11 ,a 12 ..a 1n .a 21 ,a 22 ...,a 2m ,b 1 ,b 2 ,b 3 ,...,b c )

[0051] Wherein, F is a calculation model, A is a target sound absorption efficiency, f is a target sound absorption frequency range, r is an area of ​​the through hole (40), a first thickness d1 is a thickness of the first structural layer (10) in a first direction X, a is a cross-sectional area of ​​the cavity (50) perpendicular to the first direction X, and a second thickness b1 is a thickness of the second structural layer (20) in the first direction X.

[0052] See also Figure 1 , if the number of the fourth through hole 401 and the number of the third cavity 3001 are both n, and the cross-sectional areas of the plurality of third cavities 3001 perpendicular to the first direction X are the same, then the formula can be expressed as:

[0053] A1=F(f1,r 41 ,r 42 ,...,r 4n ,d 1 ,a 3 ,b 1 )

[0054] The target sound absorption efficiency A1, the target sound absorption frequency range f1, the first thickness d1, the second thickness b1, and the cross-sectional area a of the third cavity (3001) perpendicular to the first direction X are 3 Input the calculation model F to obtain the area (r 41 ,r 42 ,...,r 4n ).

[0055] In some embodiments, the computing model is Matrix Laboratory (MATLAB). Other computing models that can implement the present application are within the protection scope of the present application and are not limited here.

[0056] In some embodiments, the cross-sectional areas of the plurality of through holes (40) perpendicular to the first direction X are inconsistent, and the cross-sectional areas of the plurality of cavities (50) perpendicular to the first direction X are also inconsistent. In this case, the ratio of the cross-sectional area of ​​the through holes (40) perpendicular to the first direction X to the cross-sectional area of ​​the cavities (50) perpendicular to the first direction X in the plurality of sound absorbing units is inconsistent, so that each sound absorbing unit can effectively absorb sound waves of different frequencies.

[0057] A sound absorbing structure of the present application can achieve double-sided sound absorption, in which case the number of the first structural layer (10) is one more than the number of the second structural layer (20). Figure 2-Figure 4 In the double-sided sound absorbing structure, the first structure layer 10 includes a first substructure layer 100, a second substructure layer 200, and a third substructure layer 300, and the second structure layer 20 includes a fifth substructure layer 1000 and a sixth substructure layer 2000. The first structure layer 10 and the second structure layer 20 are alternately stacked in sequence, the fifth substructure layer 1000 includes a plurality of first cavities 1001, the sixth substructure layer 2000 includes a plurality of second cavities 2001, the first substructure layer 100 includes a plurality of first through holes 101, the second substructure layer 200 includes a plurality of second through holes 201, and the third substructure layer 300 includes a plurality of third through holes 301. The first through holes 101, the second through holes 201, and the third through holes 301 are all circular through holes, and are arranged corresponding to the first cavity 1001 and the second cavity 2001, so that the first cavity 1001 and the second cavity 2001 form a cavity with two through holes, and the volumes of the cavities are equal. According to the Helmholtz resonator principle, the resonant frequency in the cavity is determined by the volume of the cavity and the volume of the through hole. Because the thickness of multiple through holes on the same sound absorbing plate in the first direction X is the same, and the thickness of multiple cavities on the same second structural layer (20) in the first direction X is the same, the sound absorbing structure of the present application can be formed. Therefore, when the cross-sectional areas of multiple first cavities 1001 and multiple second cavities 2001 in the second direction Y are the same, the different cross-sectional areas of at least some of the through holes 101 in the second direction will cause the resonant frequencies in at least some of the cavities to be different. In practical applications, the first noise includes a plurality of sound waves of different frequencies. The first noise enters the first cavity 1001 through the first through hole 101. The sound waves with the same resonance frequency as the first cavity 1001 will cause the air in the first cavity 1001 to vibrate. When the air vibrates, the sound waves with the same resonance frequency will generate friction with the inner wall of the first through hole 101. The friction will convert the sound wave energy into heat energy, which will be absorbed by the inner wall of the through hole, thereby achieving effective sound absorption of the sound waves with the same resonance frequency as the first cavity 1001 in the first noise. Similarly, the second noise enters the sound absorption structure through the third through hole 301, which can achieve effective sound absorption of sound waves of different frequencies in the second noise, thereby achieving double-sided sound absorption of the sound absorption structure of the present application.

[0058] Furthermore, in order to enable the double-sided sound absorption structure to achieve effective sound absorption in a wider frequency range, in certain embodiments, the cross-sectional areas of the plurality of through holes (40) of the plurality of first structural layers (10) can be calculated using a calculation model. Figure 2-Figure 4 , first confirm the target sound absorption efficiency and target sound absorption frequency of the sound absorption structure, obtain the first thickness b1 of the first substructure layer 100, the second substructure layer 200, and the third substructure layer 300 in the first direction X, the second thickness d1 of the fifth substructure layer 1000 and the sixth substructure layer 2000 in the first direction X, and the cross-sectional area (a ) of the first cavity 1001 and the second cavity 2001 perpendicular to the first direction X. 1 , a 2 ), the cross-sectional areas of the plurality of first through holes 101, the plurality of second through holes 201, and the plurality of third through holes 301 perpendicular to the first direction X are calculated by the calculation model.

[0059] A2=F(f2,r 11 ,r 12 ,...,r 1 n,r 21 ,r 22 ,..r 2 n,r 31 ,.r 3 n,d 1 ,a 1 ,a 2 ,b 1 )

[0060] The target sound absorption efficiency A2, the target sound absorption frequency range f2, the first thickness b1, the second thickness d1, and the cross-sectional area (a) of the first cavity 1001 and the second cavity 2001 perpendicular to the first direction X are calculated. 1 , a 2 ) Input the calculation model F to obtain the cross-sectional areas (r) of the n first through holes 101, the second through holes 201, and the third through holes 301 perpendicular to the first direction X. 11 ,r 12 ,...,r 1n ,r 21 ,r 22 ,..r 2n ,r 31 ,..r 3n ).

[0061] When the target sound absorption frequency ranges of the two sides are completely different and the difference exceeds 200 Hz, or the target sound absorption efficiency difference of the two sides exceeds 0.2, the double-sided sound absorption effect of the present solution is limited. At this time, the second substructure layer 200 can be set as a third structure layer 30 without through holes, so that the two opposite sides of the third structure layer 30 are single-sided sound absorption structures, and the cross-sectional areas of the through holes of the two single-sided sound absorption structures perpendicular to the first direction X can be designed respectively to achieve different frequency ranges and / or different sound absorption efficiencies.

[0062] In some embodiments, the cross-sectional areas of the corresponding through holes of the plurality of first structural layers (10) in the second direction are different, see Figure 1-Figure 4 The first through hole 101, the second through hole 201, and the third through hole 301 corresponding to the first cavity 1001 and the second cavity 2001 have different cross-sectional areas perpendicular to the first direction X. The different cross-sectional areas of the through holes corresponding to the same cavity can enable the cavity to better absorb sound waves of different frequencies.

[0063] In some embodiments, the cross-sectional areas of all through holes may be set to be the same, and the cross-sectional areas of at least some cavities may be unequal, thereby achieving effective sound absorption in a wider range of target sound absorption frequencies.

[0064] In some embodiments, the cross-sectional area of ​​the same through hole in the direction perpendicular to the first direction X is different, that is, the cross-sectional area of ​​the through hole in the first direction X is not square or rectangular, and the inner wall of the through hole is not parallel to the first direction X, that is, the inner wall of the through hole may have a certain angle relative to the first direction X, or the inner wall of the through hole is arc-shaped. At this time, the cross-sectional area of ​​the through hole is equal to the ratio of the volume of the through hole to the height of the through hole, that is, the cross-sectional area of ​​the through hole = the volume of the through hole / the height of the through hole; in some embodiments, in the direction perpendicular to the first direction X, the cross-sectional area of ​​the through hole will also take the smallest cross-sectional area or the largest cross-sectional area. In the specific implementation process, when making the sound absorbing board, it is preferred to make the through hole into a cylindrical hole, and the cross-sectional area of ​​the through hole in the second direction is equal to the cross-sectional area of ​​the through hole.

[0065] In some embodiments, the cross-sectional areas of the same cavity in the direction perpendicular to the first direction are not the same, that is, the cross-sectional area of ​​the cavity in the first direction is not square or rectangular. At this time, the cross-sectional area of ​​the cavity in the direction perpendicular to the first direction is equal to the ratio of the volume of the cavity to the height of the cavity, that is, the cross-sectional area of ​​the cavity = the volume of the cavity / the height of the cavity; in some embodiments, in the direction perpendicular to the first direction X, the cross-sectional area of ​​the cavity will also take the smallest cross-sectional area or the largest cross-sectional area. In the specific implementation process, when making the cavity layer, it is preferred to make the cavity into a grid of a cuboid or a cube. At this time, the cross-sectional area of ​​the cavity in the second direction is equal to the cross-sectional area of ​​the cavity. Of course, the cross-sectional area of ​​the cavity in the direction perpendicular to the first direction may be hexagonal or circular, etc., which will not be elaborated here.

[0066] In some embodiments, one through hole may correspond to two cavities. In this case, one through hole is divided into two sub-through holes by the two cavities. The two sub-through holes correspond to the two cavities respectively. If the two sub-through holes are of different sizes, the resonance frequencies in the two cavities may be different, thereby achieving effective sound absorption of sound waves of different frequencies. Although this embodiment has higher requirements on the stacking standard of the first structural layer (10) and the second structural layer (20), this embodiment is also within the protection scope of the present application and will not be described in detail here.

[0067] In some embodiments, the cross-section of the cavity on the second structural layer (20) perpendicular to the first direction may also be other shapes, such as a hexagon or a circle. Any second structural layer (20) that can form a cavity with the first structural layer (10) can be used as the second structural layer (20) of the present application.

[0068] In some embodiments, the cross-section of the through hole (40) perpendicular to the first direction may also be of other shapes, as long as the cross-section of the through hole (40) perpendicular to the first direction can meet the requirements of effective sound absorption at the target sound absorption frequency, and no specific limitation is made herein.

[0069] In some embodiments, the first structural layer (10) and the second structural layer (20) of the sound absorbing structure are fixedly connected, and the connection method is determined according to the materials of the first structural layer (10) and the second structural layer (20). The first structural layer (10) can be a sound absorbing board made of acoustic metamaterial; the second structural layer (20) can be a grid layer made of acoustic metamaterial, or can be made of other materials with a certain hardness, such as wood, metal, plastic, etc., which can support the strength of two adjacent sound absorbing boards, and there is no limitation here. If the materials of the first structural layer (10) and the second structural layer (20) are non-metallic materials, ultrasonic welding can be used, or glue can be used for bonding. If the materials of the first structural layer (10) and the second structural layer (20) are metallic materials, brazing can be used. The acoustic metamaterial can be a closed-cell foam plastic, plywood, hard fiberboard, asbestos cement board, etc. All kinds of acoustic metamaterials that can be used as sound absorbing structures can realize this application, and will not be repeated here.

[0070] It should be noted that, in some embodiments, the cavity (50) may be Figure 1-Figure 4 The square structure shown may also be a rectangular, hexagonal or other structure, and any second structural layer (20) that can form cavities of different volumes with the first structural layer (10) may implement the present application, and no specific limitation is made here.

[0071] It should be noted that, in some embodiments, the second structural layer (20) itself is provided with a plurality of cavities penetrating the second structural layer (20) along the first direction, and the plurality of cavities correspond to the plurality of through holes (40) and are suitable for enclosing a plurality of cavities (50) with the first structural layer (10), that is, the first structural layer (10) is not necessarily a plate-like structure with only through holes, but may also have grooves, and the grooves can form a cavity structure, and the first structural layer (10) and the second structural layer (20) can form a cavity corresponding to the through hole after being stacked, and no specific restriction is made on the first structural layer (10) herein.

[0072] In the description of this specification, the description with reference to the terms "certain embodiments", "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, unless otherwise clearly and specifically defined.

[0074] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A sound absorbing structure, characterized in that: include: A first structural layer (10) having a plurality of through holes (40), wherein the first structural layer (10) is suitable for absorbing sound waves; A second structural layer (20); Along a first direction, the first structural layer (10) and the second structural layer (20) are stacked, and the second structural layer (20) is suitable for enclosing a plurality of cavities (50) with the first structural layer (10); The through holes (40) and the cavities (50) are correspondingly connected to form a plurality of sound absorbing units; Perpendicular to the first direction, the ratio of the cross-sectional area of ​​the through hole (40) of at least part of the sound absorbing unit to the cross-sectional area of ​​the cavity (50) is different.

2. The sound absorbing structure according to claim 1, characterized in that: Perpendicular to the first direction, the cross-sectional areas of the plurality of cavities (50) are the same, and the cross-sectional areas of at least some of the through holes (40) are different; or The cross-sectional areas of the plurality of through holes (40) are the same, and the cross-sectional areas of at least some of the cavities (50) are different.

3. The sound absorbing structure according to claim 1, characterized in that: The second structural layer (20) is provided with a plurality of cavities penetrating the second structural layer (20) along the first direction, the plurality of cavities corresponding to the plurality of through holes (40) and suitable for enclosing a plurality of cavities (50) with the first structural layer (10).

4. The sound absorbing structure according to claim 1, characterized in that: There are a plurality of the first structural layer (10) and a plurality of the second structural layer (20), and the number of the first structural layer (10) is equal to the number of the second structural layer (20); and / or The number of the first structural layers (10) is one more than the number of the second structural layers (20); The first structural layer (10) and the second structural layer (20) are alternately stacked along the first direction.

5. The sound absorbing structure according to claim 4, characterized in that: In the first direction, the cross-sectional areas of the corresponding through holes (40) of at least part of the first structural layer (10) are different.

6. The sound absorbing structure according to claim 1, characterized in that: It also includes a third structural layer (30), wherein the third structural layer (30) is connected to a side of the second structural layer (20) away from the first structural layer (10), so as to close the cavity (50).

7. The sound absorbing structure according to claim 1, characterized in that: The orthographic projection of the through hole (40) on a projection plane perpendicular to the first direction is located within the orthographic projection of the cavity (50) on the projection plane.

8. The sound absorbing structure according to any one of claims 1 to 7, characterized in that: In a direction perpendicular to the first direction, the cross section of the cavity is a quadrilateral; and / or the cross section of the through hole (40) is a circle.

9. The sound absorbing structure according to any one of claims 1 to 7, characterized in that: The first connection layer and the second connection layer are connected by ultrasonic welding, soldering, or bonding.

10. The sound absorbing structure according to any one of claims 1 to 7, characterized in that: The first structural layer (10) is a sound absorbing metamaterial; and / or the second structural layer (20) is a sound absorbing metamaterial.

11. A method for manufacturing a sound absorbing structure, characterized in that: Obtaining a first structural layer (10), forming a plurality of through holes (40) in the first structural layer, wherein the first structural layer (10) is suitable for absorbing sound waves; Obtaining a second structural layer (20), and laminating and connecting the first structural layer (10) and the second structural layer (20) along a first direction to enclose a plurality of cavities (50); The through holes (40) and the cavity (50) are correspondingly connected to form a plurality of sound absorbing units, and perpendicular to the first direction, the ratio of the cross-sectional area of ​​the through holes (40) to the cross-sectional area of ​​the cavity (50) of at least some of the sound absorbing units is different.

12. The manufacturing method according to claim 11, characterized in that: The stacking and connecting of the first structural layer (10) and the second structural layer (20) to enclose a plurality of cavities (50) comprises: forming a plurality of cavities corresponding to the plurality of through holes (40) in the second structural layer (20).

13. The manufacturing method according to claim 11, characterized in that: The forming of a plurality of through holes (40) in the first structural layer comprises: obtaining a cross-sectional area of ​​each of the through holes (40); The cross-sectional area of ​​each through hole (40) is obtained based on a target sound absorption efficiency, a target sound absorption frequency, a preset value of the cross-sectional area of ​​the plurality of cavities (50) perpendicular to the first direction, a first thickness (b1) of the first structural layer (10) in the first direction, a second thickness (b2) of the second structural layer (20) perpendicular to the first direction, and a preset model.

14. The sound absorbing structure according to claim 13, characterized in that: The target sound absorption efficiency ranges from [0.3-0.9].

15. The sound absorbing structure according to claim 13, characterized in that: The target sound absorption frequency ranges from [500-1500HZ].

16. The sound absorbing structure according to claim 13, characterized in that: The cross-sectional areas of the plurality of cavities (50) are the same in a direction perpendicular to the first direction.

17. The sound absorbing structure according to claim 13, characterized in that: The preset model is Matrix Lab.

18. A sound absorbing panel, characterized in that: The invention comprises the sound absorbing structure according to any one of claims 1 to 10.

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