Sound absorption module and sound absorption structure

Abstract

The invention provides a sound absorption module and a sound absorption structure. The sound absorption module comprises a first sound absorption structure which is provided with at least one first sound absorption unit, and the first sound absorption unit is provided with an open hole and an insertion pipe extending from the open hole to an inner cavity of the first sound absorption unit; the second sound absorption structure is provided with at least one second sound absorption unit; the first sound absorption structure and the second sound absorption structure are arranged in the same face. Moreover, the first sound absorption structure is configured to absorb sound waves of a first frequency band, the second sound absorption structure is configured to absorb sound waves of a second frequency band, the lower limit value of the first frequency band is smaller than the lower limit value of the second frequency band, and the upper limit value of the first frequency band is smaller than the upper limit value of the second frequency band. According to the sound absorption module, the thickness and the preparation cost can be obviously reduced on the premise of ensuring the sound absorption bandwidth.

Description

Technical Field

[0001] The present invention relates to the technical field of sound absorption, and in particular to a sound absorption module and a sound absorption structure. Background Art

[0002] With the development of science and technology, people have increasing demands for the acoustic performance of scientific and technological products and quiet homes. Traditional porous materials already have good sound absorption properties. By introducing low-frequency super-structure sound-absorbing materials, stronger noise shielding or directional sound wave absorption effects can be achieved. This combination has important applications in traffic noise control and building sound insulation barriers.

[0003] Although the combination of porous materials and meta-structure sound-absorbing materials has great application potential, it also faces some technical challenges. For example, the structural design of porous structures and meta-structure sound-absorbing materials usually requires precise geometric control, and how to optimize the design of meta-structure sound-absorbing materials without affecting the original function of porous materials to obtain the expected performance improvement still needs further research. Summary of the invention

[0004] Based on this, the present invention aims to provide an improved sound absorbing module and sound absorbing structure to solve at least one of the above problems.

[0005] In a first aspect, the present application provides a sound absorption module, comprising:

[0006] A first sound absorbing structure having at least one first sound absorbing unit, wherein the first sound absorbing unit has an opening and an insertion tube extending from the opening to an inner cavity of the first sound absorbing unit; and

[0007] A second sound absorbing structure having at least one second sound absorbing unit;

[0008] Wherein, the first sound absorbing structure and the second sound absorbing structure are arranged in the same plane;

[0009] Furthermore, the first sound absorbing structure is configured to absorb sound waves in a first frequency band, and the second sound absorbing structure is configured to absorb sound waves in a second frequency band, the lower limit value of the first frequency band is smaller than the lower limit value of the second frequency band, and the upper limit value of the first frequency band is smaller than the upper limit value of the second frequency band.

[0010] The above-mentioned sound absorption module has at least the following beneficial effects:

[0011] 1. By arranging the first sound absorbing structure and the second sound absorbing structure in the same plane, the overall structure has only one layer, which is conducive to significantly reducing the thickness of the sound absorbing module;

[0012] 2. Under the same size of the web, the first sound absorbing structure and the second sound absorbing structure can share the web composition, so that the preparation materials required for the above-mentioned sound absorbing module are less, which is conducive to reducing the preparation cost;

[0013] 3. Through the structure of the opening and the insertion tube, the first sound absorbing unit can have a resonant cavity structure to achieve resonant sound absorption, so that the first sound absorbing structure combined with the second sound absorbing structure with a higher sound absorption frequency can ensure the sound absorption bandwidth of the sound absorption module; and the sound absorption frequency can be adjusted by changing the parameters of the opening and the insertion tube, and after the combination, the absorption of any target noise frequency band can be achieved.

[0014] 4. The resonant cavity type sound absorbing unit can unify the size and reduce the structural complexity of the sound absorbing unit, which is conducive to reducing the difficulty of preparation and further reducing the preparation cost.

[0015] In one embodiment, the upper limit value of the first frequency band is less than or equal to the lower limit value of the second frequency band.

[0016] In one embodiment, the first sound absorbing structure and the second sound absorbing structure are arranged side by side.

[0017] In one embodiment, the first sound absorbing structure has a plurality of first sound absorbing unit groups, each of which is arranged side by side in sequence along a first direction, and each of the first sound absorbing units in each of the first sound absorbing unit groups is arranged in a manner that the sound absorption frequency increases or decreases in sequence along a second direction, and the second direction is different from the first direction.

[0018] In one embodiment, the second sound absorbing unit comprises a porous sound absorbing material, and each of the porous sound absorbing materials is located on one side of the first sound absorbing structure and is arranged side by side with the first sound absorbing structure.

[0019] In one embodiment, each of the first sound absorbing units and each of the second sound absorbing units are randomly arranged side by side.

[0020] In one embodiment, at least two of the first sound absorbing units are adjacent to each other and arranged at intervals, and at least one of the second sound absorbing units is located between the two adjacent first sound absorbing units.

[0021] In one embodiment, the second sound absorbing unit includes a porous sound absorbing material and a bottom plate located on a side of the porous sound absorbing material away from the opening of the first sound absorbing unit.

[0022] In one embodiment, the first frequency band includes 500 Hz to 1200 Hz, and the second frequency band includes 1200 Hz to 10000 Hz.

[0023] In one embodiment, the radius of the opening is in the range of 1.6 mm to 3.5 mm, and the length of the insertion tube is in the range of 2 mm to 4 mm.

[0024] In one of the embodiments, the thickness of the sound absorbing module ranges from 4 mm to 20 mm.

[0025] In a second aspect, the present application provides a sound absorbing structure, comprising a plurality of sound absorbing modules as described in any of the foregoing embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of this specification or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 This is a schematic structural diagram of a sound absorption module 10 according to an embodiment of the present application;

[0028] Figure 2 1 is a schematic top view of a sound absorbing module 10 according to an embodiment of the present application;

[0029] Figure 3 for Figure 2 A schematic cross-sectional view of the AA plane of the illustrated embodiment;

[0030] Figure 4 for Figure 2 A schematic cross-sectional view of the BB surface of the illustrated embodiment;

[0031] Figure 5 Schematic diagram of a top view of a sound absorbing module 20 according to an embodiment of the present application;

[0032] Figure 6 for Figure 5 A schematic cross-sectional view of the CC plane of the illustrated embodiment;

[0033] Figure 7 This is a schematic structural diagram of a sound absorbing module 20 according to an embodiment of the present application without being filled with porous sound absorbing material;

[0034] Figure 8 This is a schematic diagram of the sound absorption effect of the first specific embodiment of the present application;

[0035] Fig. 9 This is a schematic diagram of the sound absorption effect of the second specific embodiment of the present application;

[0036] Fig.10 It is a schematic diagram comparing the sound absorption effects of the first embodiment and the second embodiment of the present application.

[0037] Component number description:

[0038] 10. Sound absorption module, 20. Sound absorption module;

[0039] 110, first sound absorbing structure, 111, first sound absorbing unit, 111A, first sound absorbing unit group, 111B, first sound absorbing unit group, 1111, opening, 1112, insertion tube, 1113, inner cavity, 120, second sound absorbing structure, 121, second sound absorbing unit;

[0040] 210. First sound absorbing structure, 211. First sound absorbing unit, 2111. Opening, 2112. Insertion tube, 2113. Inner cavity, 2114. Hard wall, 220. Second sound absorbing structure, 221. Second sound absorbing unit, 2211. Porous sound absorbing material, 2212. Bottom plate. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like 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 invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0043] 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 the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0045] Traditional materials such as glass fiber, foam board, rock wool and micro-perforated board are usually used for sound absorption in buildings. However, the sound absorption effect of porous sound-absorbing materials is mainly concentrated in the medium and high frequency bands, and the sound absorption effect in the low frequency band is poor. In order to ensure a certain sound absorption bandwidth (mainly to cover the low frequency), the thickness of the porous sound-absorbing material needs to be larger, resulting in a reduction in the indoor movable space in the building; and although the micro-perforated board can achieve better sound absorption in the low frequency band by designing the unit structure, it is limited by the number of units and the width of the structure itself, and its sound absorption bandwidth and sound absorption effect in the medium and high frequency bands are usually not as good as those of porous sound-absorbing materials.

[0046] Based on the above problems, the embodiment of the present application provides a sound absorption module that can ensure the sound absorption bandwidth, small thickness and low cost. Specifically, by setting the first sound absorption structure and the second sound absorption structure in the same plane, the overall structure has only one layer, which is conducive to significantly reducing the thickness of the sound absorption module; at the same time, under the same frame size, the first sound absorption structure and the second sound absorption structure in the sound absorption module of the present application can share the frame structure, so that the required preparation materials are less, which is conducive to reducing the preparation cost; and the sound absorption module of the present application can make the first sound absorption unit have a resonant cavity structure through the structure of the opening and the insertion tube to achieve resonant sound absorption, so that the first sound absorption structure is combined with the second sound absorption structure with a higher sound absorption frequency to ensure the sound absorption bandwidth of the sound absorption module, and the sound absorption frequency can be adjusted by changing the parameters of the opening and the insertion tube, and the absorption of any target noise frequency band can be achieved after the combination; in addition, the resonant cavity sound absorption unit can be unified in size, reducing the structural complexity of the sound absorption unit, which is conducive to reducing the difficulty of preparation and further reducing the preparation cost.

[0047] like Figures 1 to 4As shown, the embodiment of the present application provides a sound absorbing module 10, including: a first sound absorbing structure 110, having at least one first sound absorbing unit 111, the first sound absorbing unit 111 having an opening 1111 and an insertion tube 1112 extending from the opening 1111 to an inner cavity 1113 of the first sound absorbing unit 111; and a second sound absorbing structure 120, having at least one second sound absorbing unit 121; wherein the first sound absorbing structure 110 and the second sound absorbing structure 120 are arranged in the same plane; and the first sound absorbing structure 110 is configured to absorb sound waves in a first frequency band, and the second sound absorbing structure 120 is configured to absorb sound waves in a second frequency band, the lower limit value of the first frequency band is less than the lower limit value of the second frequency band, and the upper limit value of the first frequency band is less than the upper limit value of the second frequency band.

[0048] Exemplarily, the first sound absorbing unit 111 may be a Fabry-Perot resonator or a Helmholtz resonator, and correspondingly, the resonant cavity is a Fabry-Perot resonant cavity or a Helmholtz resonant cavity. By accurately describing the loss of sound waves in different resonant cavities, the impedance matching of multiple resonant cavities with different structures can be used to achieve broadband sound absorption. Optionally, by adjusting the radius of the opening 1111 and the length of the insertion tube 1112, the acoustic impedance of the first sound absorbing unit 111 can be effectively adjusted to achieve impedance matching. .

[0049] Optionally, the material of the first sound absorbing unit 111 includes one or more of polymer materials, metal materials, glass and ceramics. Optionally, the first sound absorbing unit 111 can be processed and formed by 3D printing, injection molding, molding, extrusion, die casting, or casting.

[0050] Exemplarily, the second sound absorbing unit 121 includes a porous sound absorbing material, and the porous sound absorbing material is made of a fiber material, such as a fibrous porous sound absorbing material (such as glass wool, mineral wool), a foam porous sound absorbing material (such as polyurethane foam, phenolic foam), etc.

[0051] Exemplarily, when the first frequency band is A1-B1 and the second frequency band is A1-B2, A1<A2, B1<B2. Optionally, the upper limit of the first frequency band is less than the lower limit of the second frequency band, that is, B1≤A2, which is conducive to further widening the sound absorption frequency band of the sound absorption module.

[0052] Exemplarily, the arrangement surface of the first sound absorbing structure 110 and the second sound absorbing structure 120 may be a flat surface or a curved surface.

[0053] In some embodiments of the present application, Figure 1 and Figure 2As shown, the first sound absorbing structure 110 and the second sound absorbing structure 120 are arranged side by side. Optionally, "side by side" may mean that the side edge of the first sound absorbing structure 110 and the side edge of the second sound absorbing structure 120 are arranged in contact, but it should be noted that the first sound absorbing structure 110 and the second sound absorbing structure 120 being stacked does not belong to "side by side".

[0054] Optional, continue to see Figure 2 The first sound absorbing structure 110 has a plurality of first sound absorbing unit groups 111A, 111B, ..., each first sound absorbing unit group is arranged in a row along the first direction D1, and each first sound absorbing unit in each first sound absorbing unit group is arranged along the second direction D2 in a manner that the sound absorption frequency increases or decreases in sequence, and the second direction D2 is different from the first direction D1. Optionally, the second direction D2 is perpendicular to the first direction D1. This is conducive to simplifying the structure of the sound absorbing module 10 and facilitating the preparation of the first sound absorbing structure 110.

[0055] Optionally, to simplify the preparation, each first sound absorbing unit may share the same front panel and the same back panel, and openings and insertion tubes may be provided on the same front panel to correspond to each internal cavity, respectively, to form a plurality of first sound absorbing units 111 .

[0056] Optional, such as Figure 2 and Figure 4 As shown, the second sound absorbing unit 121 includes porous sound absorbing materials, each of which is located on one side of the first sound absorbing structure 110 and arranged side by side with the first sound absorbing structure 110. Figure 4 As shown, the porous sound absorbing material can be a whole piece or composed of multiple small pieces, which can be determined according to actual design requirements. At this time, there is no shielding around the porous sound absorbing material, that is, there is no hard wall protection around it, so the sound absorption bandwidth of the porous sound absorbing material and the first sound absorbing structure 110 is more smoothly connected.

[0057] In some embodiments of the present application, Figure 5 and Figure 6 As shown, each first sound absorbing unit 211 and each second sound absorbing unit 221 in the sound absorbing module 20 are randomly arranged side by side. Exemplarily, "randomly arranged side by side" means that each first sound absorbing unit 211 and each second sound absorbing unit 221 are randomly arranged on the same surface, and the side walls of adjacent sound absorbing units are arranged in contact with each other.

[0058] Optionally, at least two first sound absorbing units 211 are adjacent and spaced apart, and at least one second sound absorbing unit 221 is located between the two adjacent first sound absorbing units 211. Optionally, the second sound absorbing unit 221 includes a porous sound absorbing material 2211 and a bottom plate 2212 located on a side of the porous sound absorbing material 2211 away from the opening of the first sound absorbing unit 211. Optionally, the porous sound absorbing material 2211 located at the edge is also provided with a side plate 2213 for limiting and fixing it. In this way, Figure 7 As shown, the porous sound absorbing material 2211 can be protected by the hard wall 2114, so that the sound absorption effect of the first sound absorbing structure 210 is closer to that of the first sound absorbing structure 210 at the junction of the frequency bands. Therefore, an obvious valley will appear at the junction. However, in the high-frequency band, the hard wall around the porous sound absorbing material 2211 can enhance its sound absorption effect to some extent.

[0059] Optionally, the bottom plate of the first sound absorbing unit 211 and the bottom plate of the second sound absorbing unit 221 can be integrally formed to simplify the manufacturing process and enhance the structural integrity of the sound absorbing module 20. Optionally, the side plate 2213 of the second sound absorbing unit 221 can also be integrally formed with the side plate of the first sound absorbing unit 211, which is also conducive to simplifying the manufacturing process and enhancing the structural integrity of the sound absorbing module 20.

[0060] In some embodiments of the present application, the sound absorption frequency band of the sound absorption module 10 / 20 includes 500 Hz to 10000 Hz, wherein the first frequency band includes 500 Hz to 1200 Hz, and the second frequency band includes 1200 Hz to 10000 Hz.

[0061] Furthermore, the radius of the opening 1111 / 2111 ranges from 1.6mm to 3.5mm, for example, it can be one of 1.6mm, 1.9mm, 2.2mm, 2.5mm, 2.8mm, 3.1mm, and 3.5mm; the length of the insertion tube 1112 / 2112 ranges from 2mm to 4mm, for example, it can be one of 2mm, 2.5mm, 3mm, 3.5mm, and 4mm.

[0062] Furthermore, the thickness of the sound absorbing module 10 / 20 ranges from 4 mm to 20 mm, for example, it can be one of 4 mm, 7 mm, 10 mm, 13 mm, 16 mm, 19 mm, and 20 mm.

[0063] The sound absorption module of the present application will be further described below through two specific embodiments. Specific embodiment 1

[0065] like Figure 1As shown, the thickness of the sound absorption module 10 is 20 mm, the format size is 202 mm*202 mm, one side is a Helmholtz resonator array (i.e., the first sound absorption structure 110) for absorbing low-frequency sound waves, and the other side is a porous sound absorption material (i.e., the second sound absorption structure 120, which can be, for example, a sponge), wherein the cavity opening and the insertion tube size of each Helmholtz resonator are different, and each Helmholtz resonator is arranged in the order of the size of the sound absorption frequency point, so that the Helmholtz resonator array has a better sound absorption effect in the low frequency band.

[0066] Among them, the radius of the opening 1111 ranges from 1.6mm to 3.5mm, for example, it can be one of 1.6mm, 1.9mm, 2.2mm, 2.5mm, 2.8mm, 3.1mm, and 3.5mm; the length of the insertion tube 1112 ranges from 2mm to 4mm, for example, it can be one of 2mm, 2.5mm, 3mm, 3.5mm, and 4mm.

[0067] Furthermore, the sound absorption module 10 was tested for sound absorption using a reverberation chamber, and the sound absorption effect was as follows: Figure 8 As shown, the sound absorption frequency band covers 500Hz to 10000Hz, wherein the main action frequency band of the Helmholtz resonator array is 500Hz to 1200Hz, and the subsequent 1200Hz to 10000Hz is the sound absorption frequency band of the porous sound absorption material. It can be seen that the sound absorption module 10 has a better sound absorption effect at 500Hz to 10000Hz. Specific embodiment 2

[0069] like Figure 5 As shown, this specific embodiment provides another arrangement of the Helmholtz resonator array and the porous sound absorbing material (such as sponge). In this specific embodiment, the Helmholtz resonators are randomly arranged, and the porous sound absorbing material is placed in the cavity between two adjacent Helmholtz resonators. The thickness of the sound absorbing module 20 is 20mm, and the format size is 201mm*201mm. The operating frequency band of the Helmholtz resonator array is 500Hz~1200Hz, and the sound absorption bandwidth of the porous sound absorbing material is 1200Hz~10000Hz. The sound absorption effect is as follows Fig. 9 As shown, it can be seen that the sound absorption module 20 has a better sound absorption effect at 500 Hz to 10000 Hz.

[0070] Among them, the radius of the opening 2111 ranges from 1.6mm to 3.5mm, for example, it can be one of 1.6mm, 1.9mm, 2.2mm, 2.5mm, 2.8mm, 3.1mm, and 3.5mm; the length of the insertion tube 2112 ranges from 2mm to 4mm, for example, it can be one of 2mm, 2.5mm, 3mm, 3.5mm, and 4mm.

[0071] The sound absorption effects of the first embodiment and the second embodiment are compared. Fig.10 As shown, the different arrangements of the Helmholtz resonator array and the porous sound-absorbing material will have a certain impact on the sound absorption effect of the sound absorption module. At about 1200Hz, where the sound absorption bandwidth of the Helmholtz resonator array and the porous sound-absorbing material are connected, the sound absorption effect will be affected by the arrangement method, and the sound absorption effect of the high-frequency band will also be affected. It can be seen that at this time, the low-frequency sound absorption effect of the sound absorption module 20 is basically the same as that of the sound absorption module 10, while the high-frequency sound absorption effect of the sound absorption module 20 is significantly better than that of the sound absorption module 10.

[0072] Therefore, the arrangement of the Helmholtz resonator array and the porous sound-absorbing material can be reasonably selected according to the design requirements to achieve the required sound absorption effect.

[0073] An embodiment of the present application also provides a sound absorbing structure, comprising a plurality of sound absorbing modules as described in any of the above embodiments.

[0074] Exemplarily, adjacent sound absorbing modules may be connected via connectors, thereby enabling the preparation of a large-scale sound absorbing structure, which is convenient for adaptation to the surface of a space or an object.

[0075] It should be noted that the numbers representing quantities or properties used to describe and claim certain embodiments of the present application should be understood to be modified by the terms "roughly", "about", "approximately" or "substantially" in some cases. For example, unless otherwise specified, "roughly", "about", "approximately" or "substantially" can indicate a ±20% variation of the value described. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0076] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A sound absorption module, characterized in that: include: A first sound absorbing structure having at least one first sound absorbing unit, wherein the first sound absorbing unit has an opening and an insertion tube extending from the opening to an inner cavity of the first sound absorbing unit; as well as, A second sound absorbing structure having at least one second sound absorbing unit; Wherein, the first sound absorbing structure and the second sound absorbing structure are arranged in the same plane; Furthermore, the first sound absorbing structure is configured to absorb sound waves in a first frequency band, and the second sound absorbing structure is configured to absorb sound waves in a second frequency band, the lower limit value of the first frequency band is smaller than the lower limit value of the second frequency band, and the upper limit value of the first frequency band is smaller than the upper limit value of the second frequency band.

2. The sound absorbing module according to claim 1, characterized in that: The upper limit value of the first frequency band is less than or equal to the lower limit value of the second frequency band.

3. The sound absorbing module according to claim 1 or 2, characterized in that: The first sound absorbing structure and the second sound absorbing structure are arranged side by side.

4. The sound absorbing module according to claim 3, characterized in that: The first sound absorbing structure has a plurality of first sound absorbing unit groups, each of which is arranged side by side in sequence along a first direction, and each of the first sound absorbing units in each of the first sound absorbing unit groups is arranged in a manner that the sound absorption frequency increases or decreases in sequence along a second direction, and the second direction is different from the first direction.

5. The sound absorbing module according to claim 3, characterized in that: The second sound absorbing unit includes porous sound absorbing materials, and each of the porous sound absorbing materials is located on one side of the first sound absorbing structure and is arranged side by side with the first sound absorbing structure.

6. The sound absorbing module according to claim 1 or 2, characterized in that: The first sound absorbing units and the second sound absorbing units are randomly arranged side by side.

7. The sound absorbing module according to claim 6, characterized in that: At least two of the first sound absorbing units are adjacent to each other and arranged at intervals, and at least one of the second sound absorbing units is located between the two adjacent first sound absorbing units.

8. The sound absorbing module according to claim 7, characterized in that: The second sound absorbing unit includes a porous sound absorbing material and a bottom plate located on a side of the porous sound absorbing material away from the opening of the first sound absorbing unit.

9. The sound absorbing module according to claim 1 or 2, characterized in that: The first frequency band includes 500 Hz to 1200 Hz, and the second frequency band includes 1200 Hz to 10000 Hz.

10. The sound absorbing module according to claim 9, characterized in that: The radius of the opening is in the range of 1.6 mm to 3.5 mm, and the length of the insertion tube is in the range of 2 mm to 4 mm.

11. The sound absorbing module according to claim 9, characterized in that: The thickness of the sound absorbing module ranges from 4 mm to 20 mm.

12. A sound absorbing structure, characterized in that: It comprises a plurality of sound absorbing modules as claimed in any one of claims 1 to 11.

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