Acoustic metamaterial sound absorption structure and vehicle noise reduction canopy

Abstract

The utility model belongs to the technical field of automotive interior parts, disclose a kind of acoustic metamaterial sound absorption structure and vehicle noise reduction canopy.Acoustic metamaterial sound absorption structure includes the sound absorption shell of plastic material, the surface of sound absorption shell is equipped with several sound absorption holes, and the inside of sound absorption shell forms closed sound absorption cavity, several independent cavities are arranged in sound absorption cavity, and sound absorption hole and independent cavity one-to-one correspondence communication.The utility model is based on helmholtz sound absorption principle, through the design of independent cavity of sound absorption hole, the efficient absorption of specific frequency band noise is realized, and plastic material is used, and the weather resistance and surface adaptability are considered, to be applicable on vehicle.The vehicle noise reduction canopy is combined with the above-mentioned acoustic metamaterial sound absorption structure, significantly improves the noise absorption efficiency, and does not need to adjust the original canopy accessory layout of vehicle, and adapts the installation demand of mainstream vehicle type.

Description

Technical Field

[0001] This utility model relates to the field of automotive interior parts technology, and in particular to an acoustic metamaterial sound-absorbing structure and a vehicle noise-reducing roof. Background Technology

[0002] As the automotive industry continues to demand higher levels of driving comfort, vehicle interior noise control has become a key technological direction. Current noise reduction methods for vehicle roofs mainly rely on traditional sound insulation materials (such as polyurethane foam and sound-absorbing cotton) or damping coatings. The principle behind these methods is to weaken noise propagation through the physical barrier or vibration damping effect of the materials. However, they have significant drawbacks: ① Traditional sound insulation materials have low noise absorption efficiency in specific low-to-mid frequency bands (such as 50-1000Hz), making it difficult to specifically address noise problems that are noticeably perceived by passengers; ② To improve noise reduction, the thickness or amount of material needs to be increased, leading to an increase in roof weight, which does not conform to the trend of lightweight vehicle design and will occupy internal installation space, affecting the arrangement of components such as sunroofs and ambient lighting.

[0003] Acoustic metamaterials, as artificial structural materials with special acoustic properties, can achieve precise control of noise in specific frequency bands through structural design. Among them, the Helmholtz sound absorption principle (which utilizes a resonant structure composed of openings and cavities to cause specific frequency noise to resonate within the cavity and be converted into heat energy for dissipation) has significant advantages in the field of noise absorption. Currently, this principle has been applied in fields such as architectural acoustics and noise reduction in home appliances, but it has not yet been applied to vehicle roofs. The main reason is that vehicle roofs have limited space, need to adapt to complex curved surfaces, and require structures that can withstand high and low temperatures and vibration stability. Traditional Helmholtz sound absorption structures (such as metal materials and one-piece molded cavities) cannot meet the usage requirements of vehicle roofs. Utility Model Content

[0004] The purpose of this invention is to provide an acoustic metamaterial sound-absorbing structure and a vehicle noise-reducing roof, which solves the problems of low absorption efficiency of existing vehicle roof noise-reducing materials for specific mid-to-low frequency noise bands, and the inability of traditional Helmholtz sound-absorbing structures in terms of material and shape to adapt to the curved shape and weather resistance requirements of vehicle roofs.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] An acoustic metamaterial sound-absorbing structure includes a sound-absorbing shell made of plastic, with a number of sound-absorbing holes on the surface of the sound-absorbing shell, and a closed sound-absorbing cavity formed inside the sound-absorbing shell. The sound-absorbing cavity contains a number of independent cavities, and the sound-absorbing holes and independent cavities are connected one-to-one.

[0007] The aperture of the sound-absorbing hole is based on the formula. Sure;

[0008] in, The aperture of the sound-absorbing hole, Target noise reduction frequency band, For the speed of sound, For the volume of an independent cavity, This refers to the wall thickness of the sound-absorbing shell.

[0009] As an alternative, the sound-absorbing shell has several ribs inside, each rib dividing the sound-absorbing cavity into several independent cavities arranged in a labyrinth.

[0010] As an alternative, the sound-absorbing holes are arranged in an array, and the spacing between adjacent sound-absorbing holes is 10mm to 20mm.

[0011] As an optional solution, the diameter of the sound-absorbing holes is 2mm to 5mm, and the number of sound-absorbing holes is 1 to 10.

[0012] On the other hand, the present invention adopts the following technical solution:

[0013] A vehicle noise reduction canopy includes a canopy body and the aforementioned acoustic metamaterial sound-absorbing structure. The acoustic metamaterial sound-absorbing structure is installed on the back side of the canopy body inside the vehicle and is adapted to the curvature of the canopy body. The canopy body has a plurality of noise inlet holes that correspond one-to-one with the sound-absorbing holes on the acoustic metamaterial sound-absorbing structure.

[0014] As an alternative, the noise inlet hole and the sound absorption hole are coaxially aligned and have the same diameter, and the opening of the noise inlet hole located on the inside of the roof body is set with rounded corners.

[0015] As an alternative, the acoustic metamaterial sound-absorbing structure has several protrusions on the surface near the canopy body, the protrusions are embedded in the canopy body, and each sound-absorbing hole is set on the protrusion.

[0016] As an optional solution, the thickness of the base material of the canopy body is set to 8mm to 10mm, and the overall thickness of the sound-absorbing shell is 5mm to 50mm.

[0017] As an alternative, the acoustic metamaterial sound-absorbing structure is fixed to the canopy body by adhesive bonding, and the bonding area covers the edge of the acoustic metamaterial sound-absorbing structure and the intersection of the ribs.

[0018] The beneficial effects of this utility model are:

[0019] This acoustic metamaterial sound-absorbing structure is based on the Helmholtz sound absorption principle. Through the design of sound-absorbing holes and independent cavities, it achieves efficient absorption of noise in a specific frequency band. It is made of plastic material to take into account both surface adaptability and weather resistance, so that it can be used in vehicles.

[0020] The noise-reducing roof of this vehicle, combined with the aforementioned acoustic metamaterial sound-absorbing structure, significantly improves noise absorption efficiency and does not require adjustments to the original roof accessory layout, making it suitable for the installation needs of mainstream vehicle models. Attached Figure Description

[0021] Figure 1 This is a surface schematic diagram of the acoustic metamaterial sound-absorbing structure provided in this embodiment of the utility model;

[0022] Figure 2 This is a schematic diagram of the internal structure of the acoustic metamaterial sound-absorbing structure provided in this embodiment of the utility model;

[0023] Figure 3 This is a sound absorption performance curve of the acoustic metamaterial sound-absorbing structure provided in this embodiment of the utility model;

[0024] Figure 4 This is an A-side view of the vehicle noise reduction canopy provided in this embodiment of the utility model;

[0025] Figure 5 This is a B-side view of the vehicle noise reduction canopy provided in this embodiment of the utility model.

[0026] In the attached image:

[0027] 1. Sound-absorbing shell; 11. Sound-absorbing holes; 12. Independent cavity; 13. Rib; 14. Protrusion;

[0028] 2. Canopy body; 21. Noise inlet hole. Detailed Implementation

[0029] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar parts or parts having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0030] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] In the description of this utility model, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "on the upper side," and "over" the second feature include the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature include the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] like Figure 1 and Figure 2 As shown, this utility model provides an acoustic metamaterial sound-absorbing structure, including a sound-absorbing shell 1 made of plastic. The surface of the sound-absorbing shell 1 is provided with a plurality of sound-absorbing holes 11. The interior of the sound-absorbing shell 1 forms a closed sound-absorbing cavity. The sound-absorbing cavity is provided with a plurality of independent cavities 12. The sound-absorbing holes 11 and the independent cavities 12 are connected in a one-to-one correspondence.

[0034] The aperture of the sound-absorbing hole 11 is determined according to the formula. Sure;

[0035] in, The aperture of the sound-absorbing hole 11 is... Target noise reduction frequency band, For the speed of sound, For the volume of the independent cavity 12, The thickness is the wall thickness of the sound-absorbing shell 1.

[0036] The above formula is derived from the Helmholtz resonance formula. Further deduction reveals that, among them The cross-sectional area of ​​the opening is... For the effective length of the opening, then , It should be noted that, To increase the fitting value based on experimental data, so as to calculate the resonant frequency more accurately and achieve efficient absorption and control of sound waves at specific frequencies.

[0037] Therefore, this acoustic metamaterial sound-absorbing structure is based on the Helmholtz sound absorption principle. Through the design of sound-absorbing holes 11 and independent cavities 12, it achieves efficient absorption of noise in a specific frequency band. It is made of plastic material to take into account both surface adaptability and weather resistance, so that it can be used in vehicles.

[0038] In some embodiments, the sound-absorbing housing 1 is provided with a plurality of ribs 13 inside, and each rib 13 divides the sound-absorbing cavity into a plurality of independent cavities 12 arranged in a labyrinth.

[0039] Here, six sound-absorbing holes 11 are used as an example, but it is not limited to this. Six independent cavities 12 arranged in a labyrinth are arranged in the sound-absorbing cavity. Each independent cavity 12 is separated by multiple ribs 13 with a thickness of 1mm to 2mm, making full use of the space inside the sound-absorbing shell 1.

[0040] Optionally, each sound-absorbing hole 11 is distributed in an array, and the spacing between adjacent sound-absorbing holes 11 is 10mm to 20mm; the diameter of the sound-absorbing hole 11 is set to 2mm to 5mm according to the target noise reduction frequency band, and the number of sound-absorbing holes 11 is 1 to 10, so as to improve the sound absorption effect.

[0041] Optionally, the sound-absorbing housing 1 is made of modified PP material, ABS engineering plastic, etc., and is integrally molded by injection molding process.

[0042] This type of plastic material can withstand a temperature range of -40℃ to 80℃, adapting to the usage environment. It also makes the acoustic metamaterial sound-absorbing structure easy to form, with no risk of cracking or falling off, solving the problem that traditional metal Helmholtz sound-absorbing structures are not suitable.

[0043] The acoustic metamaterial sound-absorbing structure has undergone rigorous environmental testing: after cycling at -40℃, the structure showed no cracking or deformation; after aging at 80℃, the material hardness change rate was ≤5%, and the sound absorption performance attenuation was ≤3%.

[0044] like Figure 3 The figure shows the sound absorption performance curve of the acoustic metamaterial sound absorption structure. From the curve, it can be seen that the acoustic metamaterial sound absorption structure has a significant noise reduction effect in the frequency range of 80Hz to 94Hz (absorption coefficient for target frequency band noise ≥0.8).

[0045] Based on this, the present invention also provides a vehicle noise reduction canopy, such as... Figure 4 and Figure 5 As shown, it includes a canopy body 2 and the aforementioned acoustic metamaterial sound-absorbing structure. The acoustic metamaterial sound-absorbing structure is installed on the back side (i.e., B side) of the inner side (A side) of the canopy body 2 and is adapted to the curvature of the canopy body 2. The canopy body 2 has a number of noise inlet holes 21 that correspond one-to-one with the sound-absorbing holes 11 on the acoustic metamaterial sound-absorbing structure.

[0046] Therefore, the noise-reducing roof of this vehicle, combined with the aforementioned acoustic metamaterial sound-absorbing structure, significantly improves noise absorption efficiency and does not require adjustments to the original roof accessory layout, thus adapting to the installation needs of mainstream vehicle models.

[0047] Optionally, the noise inlet hole 21 and the sound absorption hole 11 are coaxially aligned and have the same diameter to ensure that the noise conduction path is unobstructed. The opening of the noise inlet hole 21 located on the inner side of the canopy body 2 is set with rounded corners to reduce the reflection of noise on the hole wall during the process of noise passing through the noise inlet hole 21 and the sound absorption hole 11 to reach the acoustic metamaterial sound absorption structure, thereby improving the noise inlet efficiency.

[0048] Considering that the canopy body 2 has a certain thickness, the acoustic metamaterial sound-absorbing structure has several protrusions 14 near the surface of the canopy body 2, as detailed in [link to details]. Figure 1 The protrusion 14 is convenient to be embedded in the canopy body 2. Each sound-absorbing hole 11 is provided on the protrusion 14. The noise inlet hole 21 on the canopy body 2 is adapted to the shape of the protrusion 14 to improve the matching effect between the acoustic metamaterial sound-absorbing structure and the canopy body 2.

[0049] Optionally, the headliner body 2 consists of an outer skin and a base material. The outer skin is generally made of knitted fabric, suede fabric, non-woven fabric, etc.; the base material can be made of glass fiber reinforced PU foam composite material, glass fiber reinforced PP composite material, etc., with the thickness of the base material controlled at 8mm to 10mm, taking into account both structural strength and weight reduction requirements, and adapting to the curvature of the headliner of mainstream sedans, SUVs and other models; the sound-absorbing shell 1 of the acoustic metamaterial sound-absorbing structure is fixed to the back of the headliner body 2, with an overall thickness of 5mm to 50mm, which can be designed and adjusted according to the space of the back of the headliner of a specific model, and is integrally molded through injection molding process, perfectly adapting to the curved shape of the headliner body.

[0050] Optionally, the acoustic metamaterial sound-absorbing structure is fixed to the canopy body 2 by adhesive bonding, and the bonding area covers the edge of the acoustic metamaterial sound-absorbing structure and the intersection of the rib plate 13, ensuring that there is no risk of falling off under long-term vehicle vibration (frequency of 10Hz to 2000Hz, acceleration of 10m / s2).

[0051] Practical Application: Based on the weak frequency band of 80Hz-85Hz for a target vehicle model, the cavity volume and opening size are optimized through simulation calculations to achieve a sound absorption coefficient ≥0.85 for the target frequency band. When low-to-mid-frequency noise is generated during vehicle operation, the noise first enters the sound-absorbing holes 11 of the acoustic metamaterial sound-absorbing structure through the noise inlet 21 of the headliner body 2, and then enters the independent cavity 12. Based on the Helmholtz resonance principle, the noise resonates with the cavity wall in the independent cavity 12, converting sound energy into heat energy and ultimately achieving efficient control of noise in a specific frequency band.

[0052] In summary, this acoustic metamaterial sound-absorbing structure and vehicle noise-reducing roof have the following advantages:

[0053] 1) Precise sound absorption: Based on the Helmholtz principle, the acoustic metamaterial sound absorption structure can be designed for specific noise frequency bands in the low and mid frequency range of 50Hz to 1000Hz (the specific target frequency band can be designed according to the weak frequency band of the target vehicle). The absorption coefficient of noise in the target frequency band is ≥0.8, which significantly improves the noise reduction effect.

[0054] 2) Good spatial adaptability: The thickness of the sound-absorbing structure is controllable, which meets the installation space requirements of the back of the canopy and does not affect the arrangement of components such as sunroof and ambient lights. It can be adapted to the installation needs of mainstream sunroof models, and the one-piece injection molding process of plastic material can be adapted to the complex curved shape of the canopy.

[0055] 3) Strong weather resistance and stability: The selected plastic materials (such as modified PP, PC+ABS) can withstand a temperature range of -40℃ to 80℃, and the structure has no risk of cracking or falling off under long-term vehicle vibration environment, and its service life is consistent with that of the vehicle roof body 2.

[0056] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. An acoustic metamaterial sound-absorbing structure, characterized in that, The sound-absorbing shell (1) is made of plastic. Several sound-absorbing holes (11) are opened on the surface of the sound-absorbing shell (1). A closed sound-absorbing cavity is formed inside the sound-absorbing shell (1). Several independent cavities (12) are provided in the sound-absorbing cavity. The sound-absorbing holes (11) and the independent cavities (12) are connected one-to-one. The aperture of the sound-absorbing hole (11) is determined according to the formula. Sure; in, The aperture of the sound-absorbing hole (11) is... Target noise reduction frequency band, For the speed of sound, The volume of the independent cavity (12) is The thickness is the wall thickness of the sound-absorbing shell (1).

2. The acoustic metamaterial sound-absorbing structure according to claim 1, characterized in that, The sound-absorbing housing (1) has a number of ribs (13) inside, and each of the ribs (13) divides the sound-absorbing cavity into a number of independent cavities (12) arranged in a maze.

3. The acoustic metamaterial sound-absorbing structure according to claim 1, characterized in that, Each of the sound-absorbing holes (11) is arranged in an array, and the distance between adjacent sound-absorbing holes (11) is 10mm to 20mm.

4. The acoustic metamaterial sound-absorbing structure according to claim 1, characterized in that, The diameter of the sound-absorbing hole (11) is 2mm to 5mm, and the number of sound-absorbing holes (11) is 1 to 10.

5. A vehicle noise-reducing roof, characterized in that, The device includes a canopy body (2) and an acoustic metamaterial sound-absorbing structure as described in any one of claims 1-4. The acoustic metamaterial sound-absorbing structure is installed on the back side of the inner side of the canopy body (2) and is adapted to the curvature of the canopy body (2). The canopy body (2) has a plurality of noise inlet holes (21) that correspond one-to-one with the sound-absorbing holes (11) on the acoustic metamaterial sound-absorbing structure.

6. The vehicle noise reduction canopy according to claim 5, characterized in that, The noise inlet hole (21) and the sound absorption hole (11) are coaxially aligned and have the same diameter. The opening of the noise inlet hole (21) located on the inner side of the canopy body (2) is rounded.

7. The vehicle noise reduction canopy according to claim 5, characterized in that, The acoustic metamaterial sound-absorbing structure has several protrusions (14) on the surface near the canopy body (2), the protrusions (14) are embedded in the canopy body (2), and each sound-absorbing hole (11) is provided on the protrusion (14).

8. The vehicle noise reduction canopy according to claim 5, characterized in that, The thickness of the substrate of the canopy body (2) is set to 8mm to 10mm, and the overall thickness of the sound-absorbing shell (1) is 5mm to 50mm.

9. The vehicle noise reduction canopy according to claim 5, characterized in that, The acoustic metamaterial sound-absorbing structure is fixed to the canopy body (2) by adhesive bonding, and the bonding area covers the edge of the acoustic metamaterial sound-absorbing structure and the intersection of the rib plate (13).

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