Composite broadband ultrathin sound absorption structure
By connecting the neck structure outside the sound incident area and setting a breathable resistive material, a composite broadband ultra-thin sound absorption structure is formed, which solves the problems of insufficient low-frequency performance and large volume of traditional sound absorption structures, and achieves a wider scope of application and higher sound absorption effect.
Patent Information
- Application Number
- CN202411458885.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-18
- Publication Date
- 2025-02-11
AI Technical Summary
The traditional resonant sound absorption structure has insufficient low-frequency sound absorption performance and large volume, so it cannot be suitable for application scenarios with limited space thickness. At the same time, the sound absorption at the anti-resonance frequency is almost zero, which limits its use.
A composite broadband ultra-thin sound absorption structure is designed, by connecting the neck structure outside the sound incident area, and installing a thin-sheet air-permeable resistive material on the side of the neck structure to form a Hemholtz sound absorption structure and use air particles High frequency vibration and friction consume sound energy and enhance sound absorption performance.
It realizes that the sound absorption performance is improved without increasing the structural thickness, especially at low frequencies, expands the scope of application, and maintains a high sound absorption effect at the anti-resonance frequency.
Smart Images
Figure CN119418676A_ABST
Abstract
Description
Technical Field
[0001] The invention mainly relates to the technical field of sound absorbing structures, in particular to a composite broadband ultra-thin sound absorbing structure. Background Art
[0002] Traditional resonant sound-absorbing structures (e.g., micro-perforated plate sound-absorbing structures) have been widely used in many scenarios and have achieved good results. However, the sound absorption performance of the resonant sound-absorbing structure, especially the frequency band of the sound absorption, mainly depends on the depth of the back cavity. Therefore, the resonant sound-absorbing structure often requires a certain thickness, which cannot be applied to application scenarios with limited space thickness. At the same time, the sound absorption performance of the resonant sound-absorbing structure at low frequencies is often difficult to achieve good results due to the limitation of the back cavity depth. In addition, the sound absorption of the traditional resonant sound-absorbing structure at the anti-resonance frequency is almost zero, so it is subject to certain restrictions when used. In order to overcome the above shortcomings, it is necessary to provide a composite broadband ultra-thin sound-absorbing structure. Summary of the invention
[0003] The technical solution of the present invention aims at the technical problem that the existing technical solution is too single, and provides a solution that is significantly different from the existing technology. It mainly provides a composite broadband ultra-thin sound absorption structure to improve the defects of traditional resonant sound absorption structure in sound absorption effect and volume.
[0004] The technical solution adopted by the present invention to solve the above technical problems is: A composite broadband ultra-thin sound absorbing structure comprises a sound incident area arranged in a hollow shape and a micro-perforated plate arranged on one end surface of the sound incident area; a neck structure is connected to the outside of the sound incident area, and the neck structure extends outward within the height range where the sound incident area is located.
[0005] As an improvement to the above solution, a thin sheet of air-permeable and resistive material is provided on the side of the neck structure.
[0006] Preferably, the sheet-type air-permeable barrier material is made of non-woven fabric.
[0007] Preferably, the neck structure is a planar spiral structure.
[0008] Further preferably, the neck structure is arranged in a circular spiral.
[0009] Furthermore, the sound incident area and the neck structure cavity are filled with air.
[0010] As an improvement to the above solution, the sound incident area and the neck structure cavity are filled with porous sound absorbing material.
[0011] As an improvement to the above solution, a cavity is provided outside the sound incident area, the neck structure is connected to the cavity, and the neck structure and the cavity form a Helmholtz sound absorption structure.
[0012] As an improvement to the above solution, the shell of the sound incident area, the neck structure and the cavity is a structural plate with a cavity.
[0013] Preferably, the sound incident area is a cylindrical structure, and the cavity is coaxially arranged with the sound incident area.
[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention connects the neck structure in a communicating manner outside the sound incident area, and the neck structure extends outward within the height range where the sound incident area is located, thereby achieving the change of the depth of the back cavity of the micro-perforated plate without changing the thickness of the structure, thereby achieving better sound absorption performance (especially in low-frequency conditions) through a sound-absorbing structure with a smaller thickness, and the present invention can be suitable for application scenarios with limited space thickness. The present invention is also provided with a thin sheet-type breathable resistive material located on the side of the neck structure. When sound waves resonate with the structure through the neck channel, the sound waves excite air particles to vibrate at a high frequency. When the vibration speed is maximum, the sound energy is fully converted into the kinetic energy of the air particles, causing the air particles to rub against the thin sheet-type breathable resistive material, thereby consuming the sound energy. Moreover, since the thin sheet-type breathable resistive material has a large surface area, the number of air particles that rub can be increased to consume more sound energy. The present invention is also provided with a cavity located outside the sound incident area, and the neck structure is located in the cavity and forms a Helmholtz sound absorption structure therewith, thereby further improving the sound absorption performance of the sound absorption structure. The present invention also adopts a structural plate with a certain cavity as the shell to absorb medium and high frequency noise to meet the demand for a wider sound absorption band; and to prevent dust from entering the interior of the shell. The present invention has multiple sound absorption effects, so that the sound absorption of the sound absorption structure at the anti-resonance frequency will not be zero, thereby solving the problem that "the sound absorption of the traditional resonant sound absorption structure at the anti-resonance frequency is almost zero, so it is subject to certain restrictions when used". In summary, the present invention proposes a composite broadband ultra-thin sound absorption structure, which still has a large peak sound absorption coefficient, but a wider sound absorption band and a thinner structure, making it more applicable, especially for application scenarios with limited space thickness.
[0015] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1A schematic diagram of the structure of the composite broadband ultra-thin sound absorbing structure of the present invention at a viewing angle; Figure 2 A schematic diagram of the structure of the composite broadband ultra-thin sound absorbing structure of the present invention at another viewing angle; Figure 3 It is a schematic diagram of the structure of the composite broadband ultra-thin sound absorbing structure of the present invention after hiding the imaginary incident air domain; Figure 4 It is an axonometric perspective view of the composite broadband ultra-thin sound absorbing structure of the present invention, and the imaginary incident air domain is hidden in the figure; Figure 5 A comparison diagram of the sound absorption coefficient curves of the composite broadband ultra-thin sound absorption structure of the present invention and the sound absorption structure of a common sound absorption sheet; Figure 6 This is a sound pressure level diagram of the sound absorption effect of an example of the composite broadband ultra-thin sound absorption structure of the present invention at 1kHz; Figure 7 A comparison diagram of the sound absorption coefficient curves of the fourth embodiment and the first embodiment of the present invention; Figure 8 It is a comparison diagram of the sound absorption coefficient curves of Example 5 and Example 1 of the present invention.
[0017] In the figure, 1. imaginary incident air domain; 2. neck structure; 3. thin sheet-type breathable resistive material; 4. sound incident area; 5. micro-perforated plate; 6. cavity. DETAILED DESCRIPTION
[0018] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.
[0019] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly connected by technicians in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0020] Please refer to the attached Figure 1-Figure 3 , a composite broadband ultra-thin sound absorbing structure, comprising a neck structure 2, a sound incident area 4 and a cavity 6; The sound incident area 4 is located at the center of the sound absorbing structure and is set as a hollow structure; the top cover of the sound incident area 4 is a micro-perforated plate 5, and the sound enters from the micro-perforated plate 5; The neck structure 2 extends in a plane spiral from the center of the sound absorbing structure, and the portion where the sound incident area 4 is located is cut off by the sound incident area 4; the outer side of the neck structure 2 is composed of a thin sheet-type air-permeable barrier material 3, and the thin sheet-type air-permeable barrier material 3 is preferably a non-woven fabric; The cavity 6 is located outside the sound incident area 4 and is coaxially arranged with the sound incident area 4. Specifically, based on the outermost large cylindrical area, the volume occupied by the neck structure and the volume occupied by the sound incident area 4 are removed, and the remaining part is the cavity 6, which is an irregular structure. However, the outermost large cylinder and the sound incident area 4 are coaxial structures; The neck structure 2 and the cavity 6 form a Helmholtz sound absorption structure, the entrance of the neck structure 2 is located on the outer contour side of the sound incident area 4, and the exit is located in the cavity 6, that is, the sound incident area 4, the neck structure 2, and the cavity 6 are connected in sequence.
[0021] When used, the incident sound first enters the sound incident area 4 from the imaginary incident air domain 1. Since the micro-perforated plate 5 and the sound incident area 4 behind it form a micro-perforated plate sound absorption structure, each small hole of the micro-perforated plate sound absorption structure and its corresponding air layer behind it (the sound incident area 4 is hollow, which is connected with the neck structure 2 of the plane spiral to form the air layer behind the micro-perforated plate 5) form rows of cavity resonators. When the frequency of the incident sound wave is the same as the natural frequency of this system, the air in the neck of the micro-perforated plate 5 will vibrate violently due to resonance, generating friction and losing sound energy. , absorbing part of the incident sound; then the remaining incident sound enters the neck structure 2 from the interface between the neck structure 2 and the sound incident area 4. Since the thin-sheet air-permeable resistive material 3 on the side of the neck structure 2 can increase the surface area, when the sound wave resonates with the structure through the neck channel, the sound wave excites the air particles to vibrate at a high frequency. When the vibration speed is the largest, the sound energy is fully converted into the kinetic energy of the air particles, causing the air particles to rub against the thin-sheet air-permeable resistive material 3, thereby consuming the sound energy and achieving the purpose of sound absorption; finally, the remaining sound enters the cavity 6. In the entire process from the imaginary incident air domain 1 to the cavity 6, the sound energy is first converted into the kinetic energy of the air particles, and then converted into heat energy dissipation through friction.
[0022] Embodiment 1: Figure 4 As shown, the structure of the present invention is exemplarily given as follows: The radius of the entire composite broadband ultra-thin sound absorbing structure is 0.05m and the thickness is only 0.01m. Compared with the general sound absorbing structure, the present invention has the advantage of thin plates. The radius of the sound incident area 4 is 0.035m, and the neck structure 2 generates a parametric curve, whose parametric equation is X=0.0025*t*cos(t) m, Y=0.0025*t*sin(t) m, where the value of t is 0~6, and the cross-sectional area of the neck structure 2 is 0.008m×0.008m.
[0023] In this embodiment, the neck structure 2 has a rectangular cross-section and a circular spiral structure; the sound incident area 4 is a cylindrical structure with a circular top; only air is sealed between the top of the sound incident area 4 and the cavity of the neck structure 2 .
[0024] Comparing the sound absorption performance of the composite broadband ultra-thin sound absorption structure in Example 1 with that of the ordinary sound absorption sheet, Figure 5 As shown, it is a comparison diagram of the sound absorption coefficient curves of the two, wherein the red line is the test result of the product of the present invention, and the blue line is the sound absorption result of the traditional micro-perforated plate.
[0025] from Figure 5 It can be seen from the curve that, compared with the traditional structure, there is a sound absorption peak in the low-frequency sound range within 2k, and the peak value can achieve a sound absorption effect of more than 60%. The composite broadband ultra-thin sound absorption structure of the present invention has a significantly better sound absorption effect in the high-frequency region than the ordinary resonant sound absorption structure, which is mainly manifested in two aspects: (1) at the same thickness, the low-frequency and medium-frequency sound absorption performance of the present invention is significantly better than that of the traditional micro-perforated plate sound absorption structure; (2) the present invention also has an additional adjustable sound absorption peak at low frequency.
[0026] The actual sound absorption effect diagram of the composite broadband ultra-thin sound absorption structure of the present invention at 1kHz under a certain structure is as follows: Figure 6 As shown, from Figure 6 It can be seen that the sound wave is transmitted into the structure from the incident air domain, and the sound pressure level is the largest in the neck structure, indicating that the sound energy is effectively absorbed in the neck structure.
[0027] The invention can achieve good sound absorption effect at low frequency.
[0028] Embodiment 2: This embodiment differs from Embodiment 1 in that: In this embodiment, the cross section of the neck structure 2 is hexagonal and distributed in a circular spiral; the sound incident area 4 is a cylindrical structure with a circular top. The top of the sound incident area 4 and the cavity of the neck structure 2 are filled with a proper amount of porous sound absorbing material (such as mineral wool, glass wool, felt, wood wool sound absorbing board, etc.) to further improve the sound absorption effect of the sound absorbing structure.
[0029] The rest is the same as the first embodiment.
[0030] Embodiment 3: This embodiment differs from Embodiment 2 in that: In this embodiment, the shell forming the sound incident area 4, the neck structure 2 and the cavity 6 contours in the present invention is a structural plate with a certain cavity, which is used to absorb medium and high frequency noise and prevent dust from entering the interior of the shell.
[0031] The rest is the same as the second embodiment.
[0032] Embodiment 4: This embodiment differs from Embodiment 1 in that: In this embodiment, the spiral length of the neck structure 2 is smaller than the spiral length of the neck structure 2 in the first embodiment.
[0033] The rest is the same as the first embodiment.
[0034] The comparison of the sound absorption coefficient curves of the fourth embodiment and the first embodiment is shown in the figure below: Figure 7 As shown in the figure, the black line is the result of shortening the neck structure by a certain amount, and the parameterized curve range is 0 to 4.8pi.
[0035] Embodiment 5: This embodiment differs from Embodiment 4 in that: In this embodiment, the spiral length of the neck structure 2 is smaller than the spiral length of the neck structure 2 in the fourth embodiment.
[0036] The rest is the same as that of the fourth embodiment.
[0037] The comparison of the sound absorption coefficient curves of Example 5 and Example 1 is shown in the figure below: Figure 8 As shown in the figure, the black line is the result of shortening the neck structure by a certain amount, and the parameterized curve range is 0 to 4.6pi.
[0038] In embodiments five, four and one, the spiral length of the neck structure 2 gradually increases, so that the incident depth of the sound wave entering the cavity 6 from the sound incident area 4 increases successively, that is, the back cavity depth of the micro-perforated plate 5 increases successively, so that the sound absorbing structure can achieve the effect of sound absorption in different frequency bands and broadband sound absorption.
[0039] The above is an exemplary description of the present invention in combination with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.
Claims
1. A composite broadband ultra-thin sound absorbing structure, comprising a sound incident area (4) arranged in a hollow shape and a micro-perforated plate (5) arranged on one end surface of the sound incident area (4); characterized in that: A neck structure (2) is provided in a communicating manner outside the sound incident area (4), and the neck structure (2) extends outward within a height range where the sound incident area (4) is located.
2. The composite broadband ultra-thin sound absorbing structure according to claim 1, characterized in that: A thin sheet-type air-permeable barrier material (3) is provided on the side of the neck structure (2).
3. The composite broadband ultra-thin sound absorbing structure according to claim 2, characterized in that: The thin sheet-type air-permeable barrier material (3) is made of non-woven fabric.
4. The composite broadband ultra-thin sound absorbing structure according to claim 1, characterized in that: The neck structure (2) is a planar spiral structure.
5. The composite broadband ultra-thin sound absorbing structure according to claim 4, characterized in that: The neck structure (2) is arranged in a circular spiral.
6. The composite broadband ultra-thin sound absorbing structure according to claim 1, characterized in that: The sound incident area (4) and the cavity of the neck structure (2) are filled with air.
7. The composite broadband ultra-thin sound absorbing structure according to claim 1, characterized in that: The sound incident area (4) and the cavity of the neck structure (2) are filled with porous sound absorbing material.
8. A composite broadband ultra-thin sound absorbing structure according to claim 1 or 2, characterized in that: A cavity (6) is provided outside the sound incident area (4), the neck structure (2) is connected to the cavity (6), and the neck structure (2) and the cavity (6) form a Helmholtz sound absorption structure.
9. The composite broadband ultra-thin sound absorbing structure according to claim 8, characterized in that: The shell of the sound incident area (4), the neck structure (2) and the cavity (6) is a structural plate with a cavity.
10. The composite broadband ultra-thin sound absorbing structure according to claim 8, characterized in that: The sound incident area (4) is in a cylindrical structure, and the cavity (6) is coaxially arranged with the sound incident area (4).