A sound absorbing structure

Abstract

The present invention relates to the field of noise reduction technology, and in particular to a sound absorbing structure, which includes a first thin plate, a middle layer and a second thin plate, wherein the first thin plate and the second thin plate are arranged in parallel and spaced apart, a plurality of male joint ends are arranged in an array on one side of the first thin plate facing the middle layer, and a female joint end matching the male joint end is arranged on the side of the second thin plate facing the middle layer, wherein the middle layer is a flexible sound absorbing material, and the middle layer is sandwiched between the first thin plate and the second thin plate, and the first thin plate and the second thin plate are connected together by the mutual cooperation of the male joint end and the female joint end. The present invention can achieve a low-frequency broadband sound absorbing effect, and at the same time, can be flexibly attached, and can effectively prevent dust from invading and clumping due to moisture.

Description

Technical Field

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

[0002] Sound-absorbing structures are widely used in objects such as transportation vehicles, electromechanical equipment, building walls and industrial pipelines. They rely on the damping loss of their internal structures, such as the viscous thermal boundary layer and structural deformation damping, to convert the mechanical energy carried by sound waves into thermal energy, thereby achieving the purpose of noise reduction.

[0003] According to different working principles, traditional sound-absorbing structures can be divided into two categories: one is non-resonant sound-absorbing structures, such as porous sound-absorbing materials such as foam and fiber cotton; the other is resonant sound-absorbing structures, such as micro-perforated plates, films or thin plate resonant sound absorbers. Among them, the non-resonant sound-absorbing structure relies on the interaction between the tortuous gaps or fibers inside its own material and the sound waves to absorb sound energy. Its sound absorption performance is directly related to the thickness of the material. It has excellent mid-high frequency broadband sound absorption performance, but the absorption of low-frequency noise is not ideal; while the resonant sound-absorbing structure relies on the constructed resonance unit to achieve impedance matching with the incident side medium, and then uses its own damping loss to absorb sound energy. Its sound absorption performance is directly related to the resonant frequency of the resonance unit, so the sound absorption bandwidth is usually narrow. How to achieve better low-frequency broadband sound absorption effect under the premise of a very small thickness of the sound-absorbing structure is a difficult problem in the field of noise control.

[0004] In practical applications, since non-resonant sound-absorbing structures are usually soft in texture, they can be easily implemented on the surfaces of complex curved objects, such as pipes with large curvatures, car bulkheads and car doors, etc. However, non-resonant sound-absorbing structures are easily affected by factors such as dust intrusion and moisture clumping, and are not suitable for direct exposure in many occasions; while resonant sound-absorbing structures are usually rigid in texture and are mostly used on the surfaces of large flat objects, such as walls, sound barriers, etc.

[0005] Therefore, a sound absorbing structure is urgently needed to solve the above technical problems. Summary of the invention

[0006] The object of the present invention is to provide a sound absorbing structure which can achieve a low-frequency broadband sound absorbing effect, and at the same time, can be flexibly attached and can effectively prevent dust from intruding and clumping due to moisture.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] A sound absorbing structure comprises: a first thin plate, a middle layer and a second thin plate, wherein the first thin plate and the second thin plate are arranged in parallel and spaced apart, a plurality of male joint ends are arranged in an array on one side of the first thin plate facing the middle layer, a female joint end matching with the male joint ends is arranged on the side of the second thin plate facing the middle layer, the middle layer is a flexible sound absorbing material, the middle layer is sandwiched between the first thin plate and the second thin plate, and the first thin plate and the second thin plate are connected together by the mutual cooperation of the male joint ends and the female joint ends.

[0009] Preferably, a mass block is arranged on the first thin plate, and the mass block and the first thin plate together form a resonance unit.

[0010] Preferably, the number of the mass block is at least one.

[0011] Preferably, a through opening penetrating the middle layer body is provided at a position on the middle layer body opposite to the joint male end.

[0012] Preferably, the engaging male end comprises a first base and a protrusion, wherein the first base is arranged on the first thin plate, the protrusion is arranged at an end of the first base away from the first thin plate, and the protrusion can be inserted into the engaging female end.

[0013] Preferably, the engaging female end comprises a second base, the second base is arranged on the second thin plate, and a groove is provided at one end of the second base facing away from the second thin plate, and the protrusion can be inserted into the groove.

[0014] Preferably, the height of the protrusion is greater than or equal to the depth of the groove.

[0015] Preferably, the cross-sectional shape of the protrusion is circular or polygonal.

[0016] Preferably, first openings are distributed in an array on the first thin plate, and a plurality of the engaging male ends are arranged on the first thin plate through the first openings.

[0017] Preferably, second openings are distributed in an array on the second thin plate, and a plurality of the engaging female ends are arranged on the second thin plate through the second openings.

[0018] Beneficial effects of the present invention:

[0019] The sound absorbing structure provided by the present invention has a first thin plate with multiple resonance units, and its resonance frequency can be conveniently designed to the low-frequency domain. The sound pressure in the area where the middle layer is located is greatly improved at the resonance frequency of the resonance unit, which can improve the ability of the middle layer to absorb incident sound energy and realize the low-frequency broadband sound absorption function; the first thin plate, the second thin plate and the middle layer can all be bent, and the first thin plate and the second thin plate are connected by matching the male end and the female end, and the surface connection is changed to a multi-point connection of grooves and protrusions, which improves the flexibility of the sound absorbing structure, thereby realizing flexible attachment and facilitating attachment to the surface of a complex curved object; the first thin plate and the second thin plate are arranged on both sides of the middle layer, and the closed surfaces of the first thin plate and the second thin plate can protect the middle layer, which can effectively prevent the middle layer from being invaded by dust and clumping due to moisture. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a first implementation form of a sound absorbing structure of the present invention;

[0021] Figure 2 is a schematic diagram of a first thin plate in a sound absorbing structure of the present invention;

[0022] Figure 3 is a schematic diagram of a second thin plate in a sound absorbing structure of the present invention;

[0023] Figure 4 is a schematic diagram of a second implementation form of a sound absorbing structure of the present invention;

[0024] Figure 5 is a schematic diagram of a third implementation form of a sound absorbing structure of the present invention;

[0025] Figure 6 It is a schematic diagram of three forms of mass block arrangement in a sound absorbing structure of the present invention;

[0026] Figure 7 It is a schematic diagram of an attachment method of a sound absorbing structure of the present invention;

[0027] Figure 8 This is the test result of the normal incidence sound absorption coefficient of the first implementation form of the sound absorption structure of the present invention.

[0028] In the figure:

[0029] 11-first thin plate; 111-joining male end; 1111-first base; 1112-protrusion; 112-first opening; 113-first long plate; 114-mass block;

[0030] 12-middle body;

[0031] 13-second thin plate; 131-joining female end; 1311-second base; 1312-groove; 132-second opening; 133-second long plate;

[0032] 14- Construction object surface. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all of them.

[0034] like Figure 1-Figure 3 As shown, the sound absorbing structure provided by the present invention includes a first thin plate 11, a middle layer 12 and a second thin plate 13. The first thin plate 11 and the second thin plate 13 are arranged in parallel and spaced apart. A plurality of male joint ends 111 are arranged in an array on one side of the first thin plate 11 facing the middle layer 12. A female joint end 131 matching with the male joint end 111 is arranged on one side of the second thin plate 13 facing the middle layer 12. The middle layer 12 is a flexible sound absorbing material. The middle layer 12 is arranged between the first thin plate 11 and the second thin plate 13. The first thin plate 11 and the second thin plate 13 are connected together through the male joint end 111 and the female joint end 131 to form the whole of the sound absorbing structure.

[0035] Further, the male end 111 can be fixed on the first thin plate 11, or integrally formed with the first thin plate 11; the female end 131 can be fixed on the second thin plate 13, or integrally formed with the second thin plate 13. The following methods can also be used:

[0036] like Figure 4 As shown, the first thin plate 11 is provided with first openings 112 corresponding to the male joint ends 111, and a plurality of male joint ends 111 are arranged on the first thin plate 11 through the first openings 112. Similarly, the second thin plate 13 is provided with second openings 132 corresponding to the female joint ends 131, and a plurality of female joint ends 131 are arranged on the second thin plate 13 through the second openings 132.

[0037] Of course, if Figure 5As shown, the male joint ends 111 in the same row may also be arranged on the first long plate 113; similarly, the female joint ends 131 in the same row may be arranged on the second long plate 133. The first long plate 113 and the second long plate 133 may be used to match multiple male joint ends 111 and female joint ends 131 at one time; on the one hand, the complexity of the matching process may be reduced, and on the other hand, the flexibility of the sound absorbing structure in the direction perpendicular to the length of the first long plate 113 or the second long plate 133 may not be affected. It is worth noting that these matching modes of the male joint ends 111 and the female joint ends 131 may be interchangeable, and are not limited in detail herein.

[0038] Furthermore, the engaging male end 111 fixedly disposed on the first thin plate 11 includes a first base 1111 and a protrusion 1112 . The first base 1111 is disposed on the first thin plate 11 . The protrusion 1112 is fixedly disposed at one end of the first base 1111 away from the first thin plate 11 . The protrusion 1112 can be snapped into the engaging female end 131 .

[0039] The female joint end 131 fixedly disposed on the second thin plate 13 includes a second base 1311, which is disposed on the second thin plate 13. The second base 1311 has a groove 1312 at one end away from the second thin plate 13, which matches the protrusion 1112, and the protrusion 1112 can be inserted into the groove 1312. It is worth noting that the installation positions of the male joint end 111 and the female joint end 131 are interchangeable, that is, the male joint end 111 is located on the first thin plate 11, and the female joint end 131 is located on the second thin plate 13, which does not affect the sound absorption performance of the sound absorption structure.

[0040] Further, the height of the protrusion 1112 on the male end 111 is greater than or equal to the depth of the groove 1312 on the female end 131. The height of the protrusion 1112 on the male end 111 is equal to the depth of the groove 1312 on the female end 131. This fully matched situation is suitable for attaching to an object with a small curvature or a straight object; the height of the protrusion 1112 on the male end 111 is greater than the depth of the groove 1312 on the female end 131. This non-fully matched situation is suitable for attaching to an object with a large curvature, which can ensure that there is a large deformation offset between the second thin plate 13 and the first thin plate 11.

[0041] Further, in order to ensure a stable connection, optionally, the cross-section of the protrusion 1112 of the male end 111 and the groove 1312 of the female end 131 are consistent in shape, and can be circular or polygonal, etc., which is not limited here. The protrusion 1112 of the male end 111 and the groove 1312 of the female end 131 can be riveted, or can be glued, screwed, etc., to ensure the integrity of the sound absorbing structure.

[0042] Furthermore, a through hole penetrating the middle body 12 is provided at a position opposite to the male end 111 of the middle body 12, and the male end 111 and the female end 131 are matched through the through hole, so that the male end 111 and the female end 131 are tightly connected after matching. The middle body 12 is a flexible sound absorbing material, specifically, foam or fiber cotton.

[0043] Furthermore, a mass block 114 is provided on the first thin plate 11. Specifically, see Figure 2 At least one mass block 114 is fixedly arranged in the area of ​​the side of the first thin plate 11 not occupied by the joint male end 111, so as to form a resonance unit with the first thin plate 11. By setting the mass block 114, on the one hand, a stronger sound wave transmission capability can be provided for the first thin plate 11, and on the other hand, the mass and stiffness parameters of the first thin plate 11 can be adjusted more flexibly, thereby finally improving the sound absorption effect of the sound absorption structure.

[0044] Further, Figure 6 Schematic diagrams of three arrangements of mass blocks 114 in the resonance unit of the sound absorbing structure of the present invention. Figure 6 The mass blocks 114 on the sound absorbing structure shown in (a) are arranged in 3 rows and 3 columns. Figure 6 The sound absorbing structure shown in (b) includes mass blocks 114 arranged in 2 rows and 2 columns. Figure 6 The mass blocks 114 included in the sound absorbing structure shown in (c) are arranged in a row. In the figure, the first-order resonance frequencies of the resonance units composed of the mass blocks 114 and the first thin plate 11 are arranged from small to large and are represented by symbols F1, F2, ..., F9. Figure 6 The arrangement shown in the figure can achieve a broadband sound absorption effect. It is worth noting that the arrangement of the mass block 114 is not limited to Figure 6 The three methods are shown in the figure, and some resonance units may not include the mass block 114, or some resonance units may include more than one mass block 114, which is not limited here.

[0045] Further, Figure 6 The resonant frequency of the resonance unit is directly related to the geometric shape and material parameters of the first thin plate 11 and the mass block 114, and is also related to the arrangement spacing of adjacent joint male ends 111 and the geometric shape of the first base 1111. Therefore, the desired resonant frequency range of the resonance unit can be obtained by reasonably designing and selecting the geometric shape, arrangement spacing and material parameters of these components, thereby achieving an ideal sound absorption effect.

[0046] The working mechanism of the sound absorbing structure of the present invention is as follows:

[0047] The resonance unit in the first thin plate 11 can be conveniently designed to have a lower resonance frequency, and at its resonance frequency, it can meet the impedance matching condition with the incident side medium, so that the sound waves can smoothly enter the middle layer 12, and the sound pressure in the area where the middle layer 12 is located is greatly increased at the resonance frequency of the resonance unit. Even if the sound absorption coefficient of the sound-absorbing material constituting the middle layer 12 is very small, it can still absorb a large amount of incident sound energy. Moreover, since the main energy-consuming component is the middle layer 12, the first thin plate 11 and the second thin plate 13 have a wide range of material selections and do not need to have high structural deformation damping properties. They can be ordinary metal materials, such as galvanized steel plates or aluminum alloy plates; polymer materials, such as polycarbonate materials, can also be used. Secondly, multiple resonance units with different resonance frequencies are arranged according to a method not limited to Figure 6 In the three arrangements shown, the mutual interference between multiple resonance units with different resonance frequencies can broaden the sound absorption band of the sound absorption structure.

[0048] In addition, the first thin plate 11, the second thin plate 13 and the middle layer 12 can all be bent. There is no rigid frame inside the first thin plate 11 and the second thin plate 13. Instead, the first thin plate 11 and the second thin plate 13 are connected by matching the male end 111 and the female end 131. The surface connection is changed to a multi-point connection of grooves and protrusions, which improves the flexibility of the sound-absorbing structure, thereby achieving flexible attachment, which is convenient for attachment to the surface of complex curved objects.

[0049] In addition, the first thin plate 11 and the second thin plate 13 of the sound absorbing structure are both sealed surfaces, which can effectively prevent the middle layer 12 from being invaded by dust and clumping due to moisture, thereby ensuring the working performance and service life of the middle layer 12. The sound absorbing structure proposed by the present invention combines the advantages of non-resonance sound absorbing structure and resonance sound absorbing structure, and effectively overcomes their respective disadvantages. It can have excellent low-frequency and broadband sound absorbing performance under the premise of very small thickness, and the structure surface is sealed and soft, which is convenient for attachment to the surface of complex curved objects.

[0050] Construction method

[0051] Figure 7 The figure is a schematic diagram of an attachment method of the sound absorbing structure of the present invention. When used, the sound absorbing structure can be continuously spliced ​​to completely cover the surface 14 of the construction object; the sound absorbing structure can also be spaced a certain distance apart and arranged in a discrete manner on the surface 14 of the construction object.

[0052] For the surface of the construction object with a large curvature, the sound absorbing structure can be bent to a certain extent and then attached to the surface. In addition, the first thin plate 11 and the second thin plate 13 are pre-made into a curved shape that fits the surface 14 of the construction object, and are directly attached to the surface of the construction object with a large curvature after assembly. This ensures that the effective sound absorption frequency band of the sound absorbing structure remains consistent before and after construction, and is not affected by structural deformation during the construction process.

[0053] Test results

[0054] Figure 8 The test results of the normal incidence sound absorption coefficient of the first embodiment of the sound absorption structure of the present invention are shown in FIG. Figure 1-Figure 3 As shown. The test performed in this embodiment is performed according to the ASTM E1050-12 standard. In this embodiment, the sound absorbing structure includes the following specific parameters:

[0055] The outer contour of the sound-absorbing structure is a square with a side length of 105 mm;

[0056] The first thin plate 11 is made of polycarbonate material with a thickness of 0.125 mm; 16 joint male ends 111 in 4 rows and 4 columns are evenly arranged on the surface of the first thin plate 11; the cross-sectional shape of the first base 1111 of the joint male end 111 is a square with a side length of 10 mm and a thickness of 5 mm; the cross-sectional shape of the protrusion 1112 on the joint male end 111 is a circle with a radius of 2.5 mm and a thickness of 5 mm; the outer contour shape of the 9 mass blocks 114 distributed on the first thin plate 11 is a square with a side length ranging from 2 mm to 7 mm and a thickness of 1 mm and 2 mm, and the material is stainless steel.

[0057] The second thin plate 13 is made of polycarbonate material and has a thickness of 0.125 mm. 16 female joint ends 131 are evenly arranged in 4 rows and 4 columns on the surface of the second thin plate 13. The cross-sectional shape of the second base 1311 of the female joint end 131 is a square with a side length of 10 mm and a thickness of 5 mm. The cross-sectional shape of the groove 1312 of the female joint end 131 is a circle with a radius of 2.5 mm and a depth of 5 mm.

[0058] The middle layer 12 is glass fiber wool with a bulk density of 9.6 kg / m 3 , flow resistance is 25000Nsm -4 , thickness is 25mm.

[0059] like Figure 8 As shown, the normal incidence sound absorption coefficient of the sound absorbing structure at 500Hz-1600Hz is above 0.5, especially the sound absorption coefficient at 800Hz-1000Hz is above 0.95, and the thickness of the sound absorbing structure is only 25mm, which is much lower than the wavelength of the absorbed noise.

[0060] It is worth understanding that, in the description of the present invention, the terms "front", "rear", "inside", "outside", "positive", "negative", etc., indicating orientations or positional relationships are 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, rather than indicating or implying 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 invention.

[0061] Furthermore, in the description of the present invention, the meaning of “plurality” refers to two or more than two, unless otherwise clearly and specifically defined.

[0062] In addition, in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "matching", "connection", "attachment" and "assembly" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical or magnetic connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A sound absorbing structure, characterized in that: include: A first thin plate (11), a middle layer (12) and a second thin plate (13), wherein the first thin plate (11) and the second thin plate (13) are arranged in parallel and spaced apart, a plurality of male joint ends (111) are arranged in an array on one side of the first thin plate (11) facing the middle layer (12), and a female joint end (131) matching with the male joint ends (111) is arranged on one side of the second thin plate (13) facing the middle layer (12), wherein the middle layer (12) is a flexible sound absorbing material, and the middle layer (12) is sandwiched between the first thin plate (11) and the second thin plate (13), and the first thin plate (11) and the second thin plate (13) are connected together by the mutual cooperation between the male joint ends (111) and the female joint ends (131); A mass block (114) is arranged on the first thin plate (11), and the mass block (114) and the first thin plate (11) together form a resonance unit; A through opening penetrating the middle layer (12) is provided at a position on the middle layer (12) opposite to the joint male end (111); The number of the mass block (114) is at least one.

2. A sound absorbing structure according to claim 1, characterized in that: The engaging male end (111) comprises a first base (1111) and a protrusion (1112), wherein the first base (1111) is arranged on the first thin plate (11), and the protrusion (1112) is arranged at an end of the first base (1111) facing away from the first thin plate (11), and the protrusion (1112) can be snapped into the engaging female end (131).

3. A sound absorbing structure according to claim 2, characterized in that: The engaging female end (131) comprises a second base (1311), wherein the second base (1311) is arranged on the second thin plate (13), and a groove (1312) is provided at one end of the second base (1311) facing away from the second thin plate (13), and the protrusion (1112) can be inserted into the groove (1312).

4. A sound absorbing structure according to claim 3, characterized in that: The height of the protrusion (1112) is greater than or equal to the depth of the groove (1312).

5. A sound absorbing structure according to claim 2, characterized in that: The cross-sectional shape of the protrusion (1112) is circular or polygonal.

6. A sound absorbing structure according to claim 1, characterized in that: The first thin plate (11) has first openings (112) distributed in an array, and a plurality of the joint male ends (111) are arranged on the first thin plate (11) through the first openings (112).

7. A sound absorbing structure according to claim 1, characterized in that: The second thin plate (13) has second openings (132) distributed in an array, and a plurality of the engaging female ends (131) are arranged on the second thin plate (13) through the second openings (132).

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