A low-frequency broadband sound absorption and noise reduction module

Abstract

The present invention relates to the field of engineering noise reduction and specifically provides a low-frequency, broadband sound absorption and noise reduction module, comprising an outermost sound absorption unit and an inner sound absorption unit nested from outside to inside. The outermost sound absorption unit comprises a closed bottom plate, a closed side plate 1 surrounding the closed bottom plate, and a perforated plate 1 located at an end of the closed side plate 1 away from the closed bottom plate. The inner sound absorption unit is located within a sound absorption cavity enclosed by the closed bottom plate, the closed side plate 1, and the perforated plate 1. The inner sound absorption unit comprises a perforated plate 2 and a perforated plate 3 arranged relative to each other in the depth direction, and the perforated plates 2 and 3 are connected by the closed side plate 2. The inner sound absorption unit of adjacent sound absorption units can slide up and down in the depth direction within the outer sound absorption unit via an adjustment component to adjust the back cavity depth of the outer sound absorption unit in the adjacent sound absorption unit. This solution can broaden the sound absorption frequency band and improve the sound absorption performance across the entire low-frequency, mid-high-frequency band.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering noise reduction, and in particular to a low-frequency, broadband sound absorption and noise reduction module. Background Art

[0002] Existing sound absorption and noise reduction structures are mainly based on two principles: porous material sound absorption and resonance sound absorption:

[0003] 1. There are many tiny gaps or pores inside the porous sound-absorbing material. These tiny pores are interconnected and directly lead to the surface of the material, so it has a certain degree of air permeability. When sound waves are incident on the surface of the porous material, part of the sound waves will penetrate into the material, and part of the sound waves will be reflected on the surface of the material. Among them, the sound waves that penetrate into the material propagate in the gaps and pores. The vibrations generated by the sound waves cause the air in the pores or gaps to move, causing friction with the pore walls. The air close to the pore walls and the fiber surface is not easy to move due to the influence of the pore walls. Due to the action of friction and viscosity, a considerable part of the sound energy is converted into heat energy, thereby causing The sound waves are attenuated and the reflected sound is weakened, thus achieving the purpose of sound absorption. Secondly, the temperature of the air in the small holes increases when it is compressed and decreases when it is sparse. The thermal conduction effect of the material causes heat exchange between the air in the small holes and the hole walls and fibers, thereby gradually converting the sound energy into heat energy consumption, and the material produces a sound absorption effect. High-frequency sound waves can accelerate the vibration speed of the air particles in the gaps, and the heat exchange between the air and the hole walls is also accelerated, so that the porous material has good medium and high-frequency sound absorption performance, and its sound absorption performance is related to the size, number, and structural form of the small holes. The material needs to have a certain thickness to play a sound absorption role, but the low-frequency sound absorption performance is not good.

[0004] 2. Resonant sound absorption is based on the Helmholtz resonance sound absorption principle. When the frequency of the sound wave matches the natural frequency of the resonant sound absorption structure, resonance occurs. The sound wave excites the resonant sound absorption structure to vibrate and maximize the amplitude, thereby consuming sound energy and achieving the purpose of sound absorption. It can generally be divided into single-layer structures, double-layer structures, or multi-layer structures. Existing resonant sound absorption structures include perforated plates, micro-perforated plates, thin plate resonance, thin film resonance, slit resonance, and resonant cavity structures. Among them, perforated plates and micro-perforated plates are the most widely used. Resonant sound absorption can be designed according to the needs of low, medium, or high frequencies. It can achieve good sound absorption at low frequencies. However, because a single module only produces one resonant frequency, the effective sound absorption frequency band is narrow, and modules with different parameters need to be designed to widen the frequency. At the same time, the lower the frequency, the thicker the resonant sound absorption structure is generally, which is easily limited by the actual installation space.

[0005] In the prior art, the following patents involve low-frequency broadband sound absorption and noise reduction structures:

[0006] 1. The invention patent with the patent number "202110649775.1" and the patent name "A low-frequency broadband acoustic metamaterial composite sound absorption structure and preparation method" includes a multi-zone perforated plate and multiple sound wave channels. The first channel, the second channel and the third channel are respectively filled with porous structures; the invention has excellent low-frequency broadband sound absorption performance and is simple to manufacture and install.

[0007] 2. The patent number is "202110381785.1", and the patent name is "A method for improving the noise reduction effect of low-frequency noise reduction linings in pipelines and an invention patent for sound linings". The noise reduction effect is improved by adding a partition plate to increase the flow path length of the noise entering the cavity of the sound-absorbing unit of the sound lining. It can effectively broaden the resonant sound absorption frequency band within the limited installation height range of the sound lining, ensure the overall noise reduction amount, and do not increase wind resistance or reduce air flow.

[0008] 3. The invention patent with the patent number "201910770054.9" and the patent name "A multi-unit coupled micro-perforated plate low-frequency broadband sound absorption structure and its design method" includes multiple sound absorption units arranged in parallel and continuously, and the sound absorption unit includes a micro-perforated plate and a back cavity; the micro-perforated plates of all sound absorption units are arranged in the same plane, and the first-order peaks of all sound absorption units and at least one high-order peak of at least one sound absorption unit are evenly and continuously distributed, forming a continuous multi-peak sound absorption broadband in the medium and low frequency range; through spatial folding, the peak bandwidth can be made wider, and the bandwidth can be expanded and combined within a limited size range.

[0009] As can be seen from the above, most existing low-frequency broadband sound absorption module units adopt the structure of a perforated plate plus a back air cavity. The sound absorption structure mainly achieves low-frequency broadband sound absorption by changing the parameters of the perforated plate (aperture, perforation ratio, etc.), changing the depth of the back cavity, changing the parameters of the folded cavity, or changing the parameters of the sound-absorbing material filled in the back cavity. This can improve the low-frequency noise reduction effect to a certain extent, but there are problems such as complex structure, high processing difficulty, and difficult engineering implementation. At the same time, the existing structure also has the problem of requiring customized design for different noise reduction applications, which is not adaptable and is not conducive to engineering use.

[0010] In summary, how to design a low-frequency, broadband sound absorption and noise reduction module with a simple structure and strong versatility is a problem that needs to be solved urgently. Summary of the Invention

[0011] To solve the above-mentioned problems, the present invention provides a low-frequency, broadband sound absorption and noise reduction module, which includes a plurality of sound absorption units nested from the outside to the inside. The inner sound absorption units of adjacent sound absorption units can slide up and down within the outer sound absorption units through an adjustment component. This solution can adjust the back cavity depth of the outer sound absorption units of adjacent sound absorption units and adjust the sound absorption frequency band, thereby widening the sound absorption frequency band and improving the sound absorption performance in the entire frequency band.

[0012] To achieve the above objectives, the present invention proposes the following technical solution: a low-frequency, broadband sound absorption and noise reduction module, comprising a plurality of sound absorption units nested from outside to inside, each sound absorption unit comprising a back cavity and a perforated plate located at one end of the back cavity close to the sound source; the inner sound absorption unit among adjacent sound absorption units can slide up and down in the depth direction within the outer sound absorption unit through an adjustment component to adjust the back cavity depth of the outer sound absorption unit among the adjacent sound absorption units and adjust the sound absorption frequency band.

[0013] Preferably, the sound absorbing unit includes an outermost sound absorbing unit and an internal sound absorbing unit sequentially nested in the outermost sound absorbing unit; the back cavity of the outermost sound absorbing unit includes a closed bottom plate and a closed side plate 1 enclosed by the circumference of the closed bottom plate; a perforated plate 1 is provided opposite to the closed bottom plate at one end of the back cavity of the outermost sound absorbing unit close to the sound source, i.e., the end of the closed side plate 1 away from the closed bottom plate; the internal sound absorbing unit is located in a sound absorbing cavity enclosed by the closed bottom plate, the closed side plate 1, and the perforated plate 1.

[0014] Preferably, the internal sound absorbing unit includes a perforated plate 2 and a perforated plate 3 arranged opposite to each other in the depth direction, and the perforated plate 2 and the perforated plate 3 are connected by a closed side plate 2; the perforated plate 2 is close to the sound source, the length of the perforated plate 3 is greater than the length of the perforated plate 2, and the two ends of the perforated plate 3 are mounted on the adjustment component; the perforated plate 3 is driven to slide up and down by the adjustment component to adjust the back cavity depth of the outer sound absorbing unit in the two adjacent sound absorbing units.

[0015] Preferably, the adjustment assembly includes a guide rail 1 and a guide rail 2 respectively located on the inner walls of the closed side panel 1 and the closed side panel 2, and a slider 1 and a slider 2 are respectively provided on the guide rail 1 and the guide rail 2; the outermost internal sound absorbing unit is the internal sound absorbing unit 1, and the internal sound absorbing unit inside the internal sound absorbing unit 1 is the internal sound absorbing unit 2; the perforated plate 3 in the internal sound absorbing unit 1 is mounted on the slider 1, and the perforated plate 3 in the internal sound absorbing unit 2 is mounted on the slider 2.

[0016] Preferably, both sides of slider one and slider two are provided with bosses, and both side ends of guide rail one and guide rail two are matched with sliding grooves; slider one and slider two slide up and down in the sliding grooves of guide rail one and guide rail two respectively through the bosses; multiple locking holes are distributed on guide rail one and guide rail two, and when the positions of slider one and slider two are adjusted, slider one and slider two are locked on guide rail one and guide rail two respectively through the locking holes.

[0017] Preferably, guide rail one and guide rail two are respectively located in the middle of closed side panel one and closed side panel two; sealing rings or sealants are provided between perforated plate three of internal sound absorbing unit one and closed side panel one and guide rail one, and between perforated plate three of internal sound absorbing unit two and closed side panel two and guide rail two.

[0018] Preferably, the outermost sound absorbing unit and the inner sound absorbing unit are fully or partially filled with a sound absorber, and the lower portion of the sound absorber is in contact with the closed bottom plate or the perforated plate.

[0019] Preferably, the sound absorber 1 in the outermost sound absorbing unit is filled in the cavity 1 enclosed by the closed bottom plate, the closed side plate 1 and the perforated plate in the outermost inner sound absorbing unit; the sound absorber 2 in the inner sound absorbing unit is filled in the cavity 2 enclosed by the closed side plate 2 and the perforated plate of the adjacent inner sound absorbing unit; the heights of the sound absorber 1 and the sound absorber 2 are set according to actual needs.

[0020] Preferably, the apertures of the perforated plates 1, 2 and 3 are 0.8 mm to 10 mm in diameter, the plate thickness is 0.5 mm to 2 mm, the perforation rate is 1% to 30%, the shape is round or square, and the apertures can be the same or different.

[0021] Preferably, the first sound absorber and the second sound absorber are provided with sound absorbing holes, and the sound absorbing holes are circular, rectangular or polygonal in structure.

[0022] The beneficial effects of the present invention are:

[0023] 1. The sound absorption and noise reduction module of the present invention includes multiple sound absorption units nested from the outside to the inside. The sound absorption units include back cavities and perforated plates. The inner sound absorption units of adjacent sound absorption units can slide up and down within the outer sound absorption units through an adjustment component. By rationally designing the structural parameters of the nested perforated plates and back cavities, low-frequency, ultra-low-frequency, and mid-high-frequency sound absorption problems can be addressed, effectively widening the sound absorption frequency band.

[0024] 2. The sound absorption and noise reduction module in the present invention does not require customized development, and only requires simple nesting and installation. Its structure and processing are simple, which can reduce production costs, effectively shorten product development time, and is conducive to engineering promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the sound absorption and noise reduction module provided by an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of the structure of the outermost sound absorbing unit provided by an embodiment of the present invention.

[0027] Figure 3 2 is a schematic structural diagram of an internal sound absorbing unit 1 provided in an embodiment of the present invention.

[0028] Figure 4 It is a structural schematic diagram of the internal sound absorbing unit 2 provided in an embodiment of the present invention.

[0029] Figure 5 It is a structural schematic diagram of the guide rail and the slider provided in an embodiment of the present invention.

[0030] Figure 6 Schematic diagram of the structure of the sound absorber provided by an embodiment of the present invention.

[0031] Reference numerals: outermost sound absorbing unit 1, inner sound absorbing unit 1 2, inner sound absorbing unit 2 3, closed bottom plate 4, closed side plate 1 5, perforated plate 1 6, perforated plate 2 7, perforated plate 3 8, closed side plate 2 9, guide rail 1 10, guide rail 2 11, slider 1 12, slider 2 13, locking hole 14, sound absorber 1 15, sound absorber 2 16, sound absorbing hole 17. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following Figure 1-6 It should be understood that the specific embodiments described herein are only used to illustrate the present invention and do not constitute a limitation of the present invention.

[0033] A low-frequency broadband sound absorption and noise reduction module includes a plurality of sound absorption units nested from the outside to the inside, wherein the sound absorption unit includes a back cavity and a perforated plate located at one end of the back cavity close to the sound source. Figure 1 The S in the middle is the direction of the sound source; the inner sound absorbing unit among the adjacent sound absorbing units can slide up and down along the depth direction in the outer sound absorbing unit through the adjustment component to adjust the back cavity depth of the outer sound absorbing unit among the adjacent sound absorbing units and adjust the sound absorption frequency band.

[0034] The sound absorbing unit includes an outermost sound absorbing unit 1 and inner sound absorbing units sequentially nested in the outermost sound absorbing unit 1; Figure 1 and 2 As shown, the back cavity of the outermost sound absorbing unit 1 includes a closed bottom plate 4 and a closed side plate 1-5 surrounding the closed bottom plate 4. A perforated plate 1-6 is provided opposite the closed bottom plate 4 at one end of the back cavity of the outermost sound absorbing unit 1 close to the sound source, i.e., the end of the closed side plate 1-5 away from the closed bottom plate 4. The internal sound absorbing unit is located in the sound absorbing cavity enclosed by the closed bottom plate 4, the closed side plate 1-5, and the perforated plate 1-6.

[0035] like Figure 1 、 3As shown in Figures 4 and 5, the internal sound absorbing unit includes a perforated plate 2 7 and a perforated plate 3 8 arranged opposite to each other in the depth direction, and the perforated plate 2 7 and the perforated plate 3 8 are connected by a closed side plate 2 9; the perforated plate 2 7 is close to the sound source, the length of the perforated plate 3 8 is greater than that of the perforated plate 2 7, and both ends of the perforated plate 3 8 are mounted on the adjustment component; the perforated plate 3 8 is driven up and down by the adjustment component to adjust the back cavity depth of the outer sound absorbing unit in the two adjacent sound absorbing units; the aperture of the perforated plates 1 6, 2 7 and 3 8 is 0.8 mm to 10 mm, the plate thickness is 0.5 mm to 2 mm, the perforation rate is 1% to 30%, the shape is circular or square, and the aperture size can be the same or different.

[0036] The outermost internal sound absorbing unit is Figure 3 The internal sound absorbing unit 12 shown in the figure has an internal sound absorbing unit inside the internal sound absorbing unit 12. Figure 4 The internal sound absorbing unit 2 3 is shown; in this embodiment, a total of one internal sound absorbing unit 2 3 is included, and those skilled in the art can also set two or more internal sound absorbing units 2 3 according to actual needs.

[0037] The adjustment assembly includes a guide rail 10 and a guide rail 2 11 welded to the inner walls of the closed side panel 1 5 and the closed side panel 2 9, respectively. The guide rail 10 and the guide rail 2 11 are respectively provided with a slider 12 and a slider 2 13; the perforated plate 3 8 in the internal sound absorbing unit 1 2 is mounted on the slider 1 12, and the perforated plate 3 8 in the internal sound absorbing unit 2 3 is mounted on the slider 2 13; Figure 5 As shown, both sides of slider 12 and slider 2 13 are provided with bosses, and both side ends of guide rail 10 and guide rail 2 11 are matched with sliding grooves; slider 12 and slider 2 13 slide up and down in the sliding grooves of guide rail 10 and guide rail 2 11 respectively through the bosses; multiple locking holes 14 are evenly distributed on guide rail 10 and guide rail 2 11. When the positions of slider 12 and slider 2 13 are adjusted, slider 12 and slider 2 13 are respectively locked on guide rail 10 and guide rail 2 11 through the locking holes 14. Specifically, slider 12 and slider 2 13 can be respectively locked in the locking holes 14 on guide rail 10 and guide rail 2 11 through locking bolts.

[0038] Guide rail 10 and guide rail 2 11 are respectively located in the middle of closed side panel 1 5 and closed side panel 2 9 and are arranged along the depth direction; sealing rings or sealants are provided between perforated plate 3 8 of internal sound absorbing unit 1 2 and closed side panel 1 5 and guide rail 1 10, and between perforated plate 3 8 of internal sound absorbing unit 2 3 and closed side panel 2 9 and guide rail 2 11 to ensure the sealing performance of the sound absorbing cavity in each sound absorbing unit.

[0039] like Figure 1As shown, the outermost sound absorbing unit 1 and the inner sound absorbing unit are fully or partially filled with sound absorbers, and the lower part of the sound absorber is in contact with the closed bottom plate 4 or the perforated plate 3 8; the sound absorber in the outermost sound absorbing unit 1 is the sound absorber 15, and the sound absorber in the inner sound absorbing unit is the sound absorber 2 16; the sound absorber 15 is filled in the cavity 1 enclosed by the closed bottom plate 4, the closed side plate 1 5 and the perforated plate 3 8 in the outermost inner sound absorbing unit; the sound absorber 2 16 is filled in the cavity 2 enclosed by the closed side plate 2 9 and the perforated plate 3 8 of the adjacent inner sound absorbing unit; the heights of the sound absorber 15 and the sound absorber 2 16 are set according to actual needs; the innermost inner sound absorbing unit, that is, the inner sound absorbing unit 2 3 in this embodiment, can also be provided with the sound absorber 2 16 according to actual needs; as shown Figure 6 As shown, the sound absorbing body 15 and the sound absorbing body 2 16 are provided with sound absorbing holes 17, and the sound absorbing holes 17 are circular as shown in c, rectangular as shown in b, or other polygonal structures.

[0040] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0041] The above specific embodiments of the present invention do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A low-frequency broadband sound absorption and noise reduction module, characterized in that: The invention comprises a plurality of sound absorbing units nested from outside to inside, wherein the sound absorbing units comprise a back cavity and a perforated plate located at one end of the back cavity close to a sound source; the inner sound absorbing unit among adjacent sound absorbing units can slide up and down along the depth direction in the outer sound absorbing unit through an adjustment component to adjust the back cavity depth of the outer sound absorbing unit among adjacent sound absorbing units and adjust the sound absorption frequency band; the sound absorbing unit comprises an outermost sound absorbing unit (1) and inner sound absorbing units nested in the outermost sound absorbing unit (1) in sequence; the outermost sound absorbing unit (1) ) comprises a closed bottom plate (4) and a closed side plate (5) enclosed on the side of the closed bottom plate (4); a perforated plate (6) is provided opposite to the closed bottom plate (4) at one end of the back cavity of the outermost sound absorbing unit (1) close to the sound source, i.e., the end of the closed side plate (5) away from the closed bottom plate (4); the internal sound absorbing unit is located in the sound absorbing cavity enclosed by the closed bottom plate (4), the closed side plate (5) and the perforated plate (6); the internal sound absorbing unit comprises perforated plates (7) arranged opposite to each other in the depth direction. and perforated plate three (8), perforated plate two (7) and perforated plate three (8) are connected by closed side plate two (9); perforated plate two (7) is close to the sound source, the length of perforated plate three (8) is greater than the length of perforated plate two (7) and both ends of perforated plate three (8) are mounted on the adjustment component; the adjustment component drives perforated plate three (8) to slide up and down to adjust the back cavity depth of the outer sound absorbing unit in the two adjacent sound absorbing units; the adjustment component includes a plurality of holes respectively located on the inner wall of closed side plate one (5) and closed side plate two (9) The guide rail 1 (10) and the guide rail 2 (11) are provided on the guide rail 1 (10) and the guide rail 2 (11), respectively, with a slider 1 (12) and a slider 2 (13); the outermost internal sound absorbing unit is the internal sound absorbing unit 1 (2), the internal sound absorbing unit inside the internal sound absorbing unit 1 (2) is the internal sound absorbing unit 2 (3), the perforated plate 3 (8) in the internal sound absorbing unit 1 (2) is mounted on the slider 1 (12), and the perforated plate 3 (8) in the internal sound absorbing unit 2 (3) is mounted on the slider 2 (13).

2. The low-frequency broadband sound absorption and noise reduction module according to claim 1, characterized in that: Both sides of the slider 1 (12) and the slider 2 (13) are provided with bosses, and both side ends of the guide rail 1 (10) and the guide rail 2 (11) are provided with sliding grooves matching the bosses; the slider 1 (12) and the slider 2 (13) slide up and down in the sliding grooves of the guide rail 1 (10) and the guide rail 2 (11) respectively through the bosses; a plurality of locking holes (14) are distributed on the guide rail 1 (10) and the guide rail 2 (11), and when the positions of the slider 1 (12) and the slider 2 (13) are adjusted, the slider 1 (12) and the slider 2 (13) are locked on the guide rail 1 (10) and the guide rail 2 (11) respectively through the locking holes (14).

3. The low-frequency broadband sound absorption and noise reduction module according to claim 2, characterized in that: The guide rail 1 (10) and the guide rail 2 (11) are respectively located in the middle of the closed side panel 1 (5) and the closed side panel 2 (9); a sealing ring or sealant is provided between the perforated plate 3 (8) of the internal sound absorbing unit 1 (2) and the closed side panel 1 (5) and the guide rail 1 (10), and between the perforated plate 3 (8) of the internal sound absorbing unit 2 (3) and the closed side panel 2 (9) and the guide rail 2 (11).

4. The low-frequency broadband sound absorption and noise reduction module according to any one of claims 1 to 3, characterized in that: The outermost sound absorbing unit (1) and the inner sound absorbing unit are all or partially filled with a sound absorbing body, and the lower part of the sound absorbing body is in contact with the closed bottom plate (4) or the perforated plate three (8).

5. The low-frequency broadband sound absorption and noise reduction module according to claim 4, characterized in that: The sound absorbing body 1 (15) in the outermost sound absorbing unit (1) is filled in the cavity 1 formed by the closed bottom plate (4), the closed side plate 1 (5) and the perforated plate 3 (8) in the outermost internal sound absorbing unit; the sound absorbing body 2 (16) in the internal sound absorbing unit is filled in the cavity 2 formed by the closed side plate 2 (9) and the perforated plate 3 (8) of the adjacent internal sound absorbing unit; the heights of the sound absorbing body 1 (15) and the sound absorbing body 2 (16) are set according to actual needs.

6. The low-frequency broadband sound absorption and noise reduction module according to claim 5, characterized in that: The apertures of the perforated plate 1 (6), perforated plate 2 (7) and perforated plate 3 (8) are 0.8 mm to 10 mm in diameter, 0.5 mm to 2 mm in thickness, 1% to 30% in perforation rate, and are circular or square in shape. The apertures may be the same or different in size.

7. The low-frequency broadband sound absorption and noise reduction module according to claim 6, characterized in that: The first sound absorbing body (15) and the second sound absorbing body (16) are provided with sound absorbing holes (17), and the sound absorbing holes (17) are circular, rectangular or polygonal structures.

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