Sound insulation and noise reduction structure of automobile roof

Abstract

The sound insulation and noise reduction structure comprises a car roof main body, and the car roof main body is sequentially provided with a car roof outer plate, an active noise reduction layer, a multi-frequency-band sound absorption layer, a partition cavity layer and an interior attachment layer from top to bottom. Through the gradient density design of the multi-band sound absorption layer, the targeted optimization of the Helmholtz resonant cavity plate and the targeted unfolding and folding of the adjustable turbulent flow wings, the automobile can adapt to different scenes such as high-speed commuting, urban congestion and rainy and snowy weather when the automobile runs, and the driving quietness is improved.

Description

Technical Field

[0001] This invention relates to the field of sound insulation and noise reduction technology for automobile roofs, specifically to a sound insulation and noise reduction structure for automobile roofs. Background Technology

[0002] With the development of the automotive industry, vehicle comfort has become a key focus for users. As a major upper interior component of a vehicle, the sound insulation and noise reduction performance of the car roof directly affects the driving and riding experience. Traditional car roofs mostly use single or multiple layers of sound-absorbing materials for passive sound insulation, but their effectiveness in suppressing low-frequency noise and wind noise is limited.

[0003] A search revealed Chinese patent CN115626122A, which discloses a sound insulation and noise reduction structure for a car roof. When the airflow channel is under negative pressure, the top of the elastic stabilizer expands, causing the stabilizer and its connected sponge layer to rise. This pulls the interior tarpaulin and sponge layer tightly against the partition plate, reducing roof vibration. Furthermore, when the vehicle is in motion, an electric gate valve can be opened to allow air to flow through the airflow channel, disrupting sound transmission and further reducing noise from the roof. However, this patented product relies on negative pressure in the airflow channel for expansion. At low speeds, insufficient negative pressure prevents the elastic stabilizer from effectively tightening the interior tarpaulin, resulting in unstable vibration and noise reduction. Additionally, traditional structural materials are inadequate in terms of heat insulation, flame retardancy, lightweighting, and environmental recyclability, failing to meet the dual demands of modern automobiles for driving comfort and green development.

[0004] To address this issue, the present invention proposes a multi-dimensional collaborative and intelligent response automotive roof sound insulation and noise reduction structure, thereby solving the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a sound insulation and noise reduction structure for a car roof in order to solve the above-mentioned problems.

[0006] This invention achieves the above-mentioned objectives through the following technical solution: a sound insulation and noise reduction structure for a car roof, comprising a roof body, wherein the roof body is provided with, from top to bottom, an outer roof panel, an active noise reduction layer, a multi-band sound absorption layer, a partitioned cavity layer, and an interior trim attachment layer; an adjustable spoiler wing is provided at one end of the outer side of the roof panel, and multiple vortex generators are equidistantly arranged at the top of the adjustable spoiler wing; embedded piezoelectric films and miniature speakers are equidistantly and alternately arranged inside the active noise reduction layer; the multi-band sound absorption layer is arranged in a gradient, and the multi-band sound absorption layer is provided with high-frequency absorption layers from top to bottom; The system comprises a high-density polyurethane layer, an open-cell foam layer, and a Helmholtz resonant cavity plate. The partitioned cavity layer is divided into three zones: a front airbag group, a middle airbag group, and a rear airbag group. A miniature air pump is located in the middle of the side of the front airbag group away from the middle airbag group. The output end of the miniature air pump is equipped with a main flow pipe. A branch flow pipe is located at the position where the main flow pipe connects to the front airbag group, the middle airbag group, and the rear airbag group. Each branch flow pipe is equipped with an intelligent pressure regulating valve at its connection point with each airbag. The interior trim layer is composed of environmentally friendly microfiber fabric.

[0007] Preferably, the main body of the roof has a placement groove at the position of the adjustable spoiler, and the bottom and sides of the placement groove are provided with sealing strips. A rotating rod is provided at the connection between one side of the adjustable spoiler and the placement groove, and a drive motor is provided at one end of the rotating rod. The drive motor is located inside the outer panel of the roof.

[0008] Preferably, a reduction gear set is provided between the output shaft of the drive motor and the rotating rod, and the reduction ratio of the reduction gear set is 10:1 to 20:1.

[0009] Preferably, the front airbag assembly is located on the side of the main body of the roof near the adjustable spoiler, and the deployment angle of the adjustable spoiler is towards the rear airbag assembly.

[0010] Preferably, the front airbag group has 8 airbags, the middle airbag group has 12 airbags, and the rear airbag group has 4 airbags. Exhaust pipes are provided on both sides of the front airbag group, the middle airbag group, and the rear airbag group near the main body of the roof.

[0011] Preferably, the outer surface of the roof panel is provided with a microporous sound-absorbing coating.

[0012] Preferably, the Helmholtz resonant cavity plate is composed of a plurality of regularly arranged resonant cavity units, each of the resonant cavity units including a cylindrical cavity and a neck tube communicating with the cavity.

[0013] Preferably, the open-cell foam layer is made of gradient density melamine-formaldehyde foam, with its density decreasing from 80 kg / m³ to 15 kg / m³ from top to bottom.

[0014] Preferably, the density of the high-density polyurethane layer is 60-80 kg / m³.

[0015] The present invention has the following beneficial effects:

[0016] 1. Through the gradient density design of the multi-band sound-absorbing layer and the targeted optimization of the Helmholtz resonant cavity plate, it effectively absorbs low-frequency vibration noise of 80-300Hz, mid-frequency noise of 500-2000Hz and high-frequency wind noise / rain noise of 2000-5000Hz. It can adapt to different scenarios such as high-speed commuting, urban congestion, rain and snow weather, with a noise reduction of 10-16dB, significantly improving the quietness of driving and riding.

[0017] 2. By combining FFT spectrum analysis, LMS adaptive filtering, and fuzzy logic scene recognition algorithms, the vehicle driving environment is judged, and the actions of the adjustable spoiler and the partitioned airbag group are coordinated to achieve adaptive adjustment of the adjustable spoiler and targeted activation of different partitioned airbag groups between low speed and high speed, so as to meet the requirements of the car roof for sound insulation and noise reduction of the vehicle interior under different vehicle conditions.

[0018] 3. By deploying spoilers at high speeds to optimize airflow and increase airbag pressure to enhance rigidity, and retracting spoilers at low speeds to reduce airbag pressure and ensure comfort, the problem of unstable noise reduction effect of traditional structures is solved.

[0019] 4. The core components of the car roof are made of lightweight and environmentally friendly materials such as carbon fiber composite materials, TPU film, and recycled substrates. While optimizing sound insulation performance, the weight of the roof can be controlled, which can reduce the fuel consumption of the car to a certain extent. Moreover, the materials have a high recyclability rate and no harmful volatile substances, which meets the needs of green development of automobiles. Attached Figure Description

[0020] Figure 1 This is a three-dimensional view of the overall structure of a sound insulation and noise reduction structure for an automobile roof proposed in this invention;

[0021] Figure 2 for Figure 1 Enlarged view of the structure at point A in the middle;

[0022] Figure 3 This is a three-dimensional view of the overall structure of a sound insulation and noise reduction structure for an automobile roof proposed in this invention;

[0023] Figure 4 for Figure 3 Enlarged view of the structure at point B in the middle;

[0024] Figure 5This is a three-dimensional view of the partitioned cavity layer structure of a sound insulation and noise reduction structure for an automobile roof proposed in this invention;

[0025] Figure 6 for Figure 5 Enlarged view of the structure at point C.

[0026] In the diagram: 1. Main body of the roof; 2. Outer roof panel; 201. Microporous sound-absorbing coating; 202. Eddy current generator; 203. Drive motor; 204. Rotating rod; 205. Adjustable spoiler wing; 206. Placement slot; 207. Reduction gear set; 208. Sealing strip; 3. Active noise reduction layer; 301. Embedded piezoelectric film; 302. Miniature speaker; 4. Multi-band sound-absorbing layer; 401. High-density polyethylene 402. Polyurethane layer; 403. Open-cell foam layer; 404. Helmholtz resonant cavity plate; 405. Resonant cavity unit; 406. Cylindrical cavity; 407. Neck tube; 508. Zoned cavity layer; 501. Front airbag assembly; 502. Middle airbag assembly; 503. Rear airbag assembly; 504. Miniature air pump; 505. Main flow tube; 506. Branch tube; 507. Exhaust tube; 508. Intelligent pressure regulating valve. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0028] Example 1:

[0029] Reference Figure 1-6 A sound insulation and noise reduction structure for a car roof includes a roof body 1. The roof body 1, from top to bottom, is provided with an outer roof panel 2, an active noise reduction layer 3, a multi-band sound-absorbing layer 4, a partitioned cavity layer 5, and an interior trim attachment layer 6. An adjustable spoiler 205 is provided at one end of the outer side of the outer roof panel 2. Multiple vortex generators 202 are equidistantly arranged at the top of the adjustable spoiler 205. The active noise reduction layer 3 contains equidistantly spaced and staggered embedded piezoelectric films 301 and miniature speakers 302. The multi-band sound-absorbing layer 4 is arranged in a gradient, and from top to bottom, it comprises a high-density polyurethane layer 401, an open-cell foam layer 402, and a... The Mönchs resonant cavity plate 403 is divided into three zones within the partitioned cavity layer 5. The partitioned cavity layer 5 includes a front airbag group 501, a middle airbag group 502, and a rear airbag group 503. A miniature air pump 504 is located in the middle of the side of the front airbag group 501 away from the middle airbag group 502. A main flow pipe 505 is located at the output end of the miniature air pump 504. A branch pipe 506 is located at the position where the main flow pipe 505 connects to the front airbag group 501, the middle airbag group 502, and the rear airbag group 503. A smart pressure regulating valve 508 is located at the connection point between the branch pipe 506 and each airbag. The interior coating layer 6 is composed of environmentally friendly microfiber fabric.

[0030] The front airbag assembly 501 is located on the side of the main body of the roof 1 near the adjustable spoiler 205. The deployment angle of the adjustable spoiler 205 faces the rear airbag assembly 503. The front airbag assembly 501 has 8 airbags, the middle airbag assembly 502 has 12 airbags, and the rear airbag assembly 503 has 4 airbags. Exhaust pipes 507 are provided on both sides of the front airbag assembly 501, the middle airbag assembly 502, and the rear airbag assembly 503 near the main body of the roof 1.

[0031] The outer surface of the roof panel 2 is provided with a microporous sound-absorbing coating 201.

[0032] The Helmholtz resonant cavity plate 403 is composed of multiple regularly arranged resonant cavity units 4031. Each resonant cavity unit 4031 includes a cylindrical cavity 4032 and a neck tube 4033 communicating with the cavity.

[0033] The open-cell foam layer 402 is made of gradient density melamine-formaldehyde foam, with its density decreasing from 80 kg / m³ to 15 kg / m³ from top to bottom. The density of the high-density polyurethane layer 401 is 60-80 kg / m³.

[0034] In this embodiment, it should be noted that the microporous sound-absorbing coating 201 is composed of water-based polyurethane and nano-level sound-absorbing ceramic microspheres, which can absorb high-frequency wind noise and rain noise. The eddy current generator 202 is a triangular protrusion with a height of 2-3mm, which is used to optimize the airflow on the roof surface, delay laminar flow separation, and reduce high-speed wind noise.

[0035] The embedded piezoelectric film 301, made of polyvinylidene fluoride (PVDF) with a thickness of 0.1 mm, is used to collect vibrations of the vehicle roof structure in real time. The miniature speaker 302 is a 10 mm diameter moving-coil speaker with a spacing of 250 mm. The active noise cancellation layer 3 collects vibration and noise signals through a dedicated control module, and generates inverse sound waves through digital signal processing (DSP) to achieve active noise cancellation.

[0036] The multi-band sound-absorbing layer 4 is located below the active noise-canceling layer 3 and adopts a gradient density design, comprising, from top to bottom:

[0037] High-density polyurethane layer 401: density is 60-80 kg / m³, thickness is 8 mm, used to absorb high-frequency noise; open-cell foam layer 402 is made of melamine-formaldehyde foam, density decreases from 80 kg / m³ to 15 kg / m³ from top to bottom, thickness is 20 mm, used to absorb mid-frequency noise; Helmholtz resonant cavity plate 403 is composed of multiple regularly arranged resonant cavity units 4031, used to absorb low-frequency noise (such as engine and road vibration) in the range of 80-300 Hz.

[0038] The front airbag group 501 contains 8 airbags located in the area above the driver and front passenger's heads; the center airbag group 502 contains 12 airbags, covering the rear passenger area; and the rear airbag group 503 contains 4 airbags located in the rear of the roof. The airbags are made of thermoplastic polyurethane (TPU) film, and each airbag integrates a miniature air pressure sensor.

[0039] When the vehicle is in motion, the system automatically adjusts based on vehicle speed, noise spectrum, and vibration signals:

[0040] High-speed operation (>100km / h): Adjustable spoiler wing 205 unfolds at a certain angle, vortex generator 202 optimizes airflow; front airbag group 501 pressure is adjusted to 1.5bar, middle zone 1.2bar, rear zone 1.0bar to improve roof rigidity and suppress wind noise; active noise reduction layer 3 actively cancels wind noise frequency band.

[0041] In low-to-medium speed urban driving conditions: the adjustable spoiler 205 retracts, reducing the airbag pressure to 0.8-1.0 bar, improving comfort; the open-cell foam layer 402 and the Helmholtz resonant cavity plate 403 work together to absorb road noise and engine noise.

[0042] Rainy or snowy weather: The microporous sound-absorbing coating 201 and the multi-band sound-absorbing layer 4 work together to suppress rain noise; the intelligent pressure regulating valve 508 finely adjusts the airbag pressure according to the humidity signal to prevent condensation.

[0043] like Figure 2 as well as Figure 4 As shown, the vortex generator 202 adopts a composite material structure integrally formed with the adjustable spoiler wing 205. The surface of the vortex generator 202 is covered with a hydrophobic coating to ensure that it can still work effectively in rainy and snowy weather.

[0044] Example 2:

[0045] Unlike Example 1, referring to Figure 1-4 This embodiment also has the following further features: the main body 1 of the roof is provided with a placement groove 206 at the position of the adjustable spoiler 205, and the bottom and sides of the placement groove 206 are provided with sealing strips 208. A rotating rod 204 is provided at the connection between one side of the adjustable spoiler 205 and the placement groove 206, and a drive motor 203 is provided at one end of the rotating rod 204. The drive motor 203 is located inside the outer panel 2 of the roof.

[0046] A reduction gear set 207 is provided between the output shaft of the drive motor 203 and the rotating rod 204. The reduction ratio of the reduction gear set 207 is 10:1 to 20:1.

[0047] In this embodiment, it should be noted that: the bottom and sides of the placement groove 206 are provided with elastic sealing strips 208. When the adjustable spoiler wing 205 is fully retracted, the sealing strip 208 is compressed to achieve airtight and waterproof sealing.

[0048] The drive motor 203 is a waterproof DC servo motor. A reduction gear set 207 is provided between its output shaft and the rotating rod 204. The reduction ratio is 15:1 to ensure sufficient output torque and angle control accuracy.

[0049] The drive motor 203 is controlled by the vehicle controller via pulse width modulation (PWM) signal. Based on real-time vehicle speed and wind noise sensor feedback, the angle of the adjustable spoiler 205 can be infinitely adjusted between 0° (fully retracted) and 25° (maximum deployment). At the same time, the rotating rod 204 has a built-in angle sensor to provide real-time feedback on the wing surface position, realizing closed-loop control.

[0050] The reduction gear set 207 uses powder metallurgy gears, which run smoothly and have low noise. It also has a self-locking function and can maintain stability at any angle without continuous power supply.

[0051] When the vehicle enters a highway or expressway, the vehicle speed sensor signal triggers the control program of the adjustable spoiler 205: the controller calculates the optimal deployment angle (e.g., 15° for a vehicle speed of 120km / h), and the drive motor 203 drives the rotating rod 204 to rotate through the reduction gear set 207, so that the spoiler 205 is smoothly deployed to the target angle; after deployment, the vortex generator 202 disrupts the laminar flow at the leading edge of the roof, delays airflow separation, and reduces wind resistance and wind noise. At the same time, the system adjusts the pressure of the front airbag assembly 501 to enhance the rigidity of the front of the roof and further suppress the vibration and noise caused by the airflow impact.

[0052] When the vehicle slows down or stops, the adjustable spoiler 205 automatically retracts into the placement slot 206. The sealing strip 208 ensures that the surface is flat and there is no wind noise when it is retracted, and it also has waterproof and dustproof functions.

[0053] Example 3: For daily high-speed commuting environments (vehicle speed 80-120km / h)

[0054] For family cars, at speeds of 80-120km / h, the wind noise from the roof mainly consists of high-frequency wind noise (800-2000Hz) and structural resonance noise (100-300Hz).

[0055] The microporous sound-absorbing coating 201 of the roof outer panel 2 is made of water-based polyurethane + 200nm sound-absorbing ceramic microspheres with a thickness of 0.5mm; the adjustable spoiler wing 205 is made of carbon fiber composite material with a length of 80cm and a width of 12cm; the vortex generator 202 is a triangular protrusion with a height of 2.5mm, a spacing of 5cm, and a quantity of 16.

[0056] The embedded piezoelectric film 301 in the active noise reduction layer 3 is made of PVDF material, with a thickness of 0.1mm, an arrangement spacing of 25cm, and a quantity of 8 pieces; the miniature speaker 302 has a diameter of 10mm, a power of 2W, an arrangement spacing of 25cm, and a quantity of 8 pieces; the DSP control module has a sampling rate of 48kHz and a delay of ≤5ms.

[0057] In the multi-band sound-absorbing layer 4, the high-density polyurethane layer 401 has a density of 70 kg / m³ and a thickness of 8 mm; the open-cell foam layer 402 is melamine-formaldehyde foam with a gradient density of 80→45→15 kg / m³ and a total thickness of 20 mm; the Helmholtz resonant cavity plate 403 contains 300 resonant cavity units 4031, the cylindrical cavity 4032 has a diameter of 15 mm and a height of 20 mm, the neck tube 4033 has a diameter of 3 mm and a length of 8 mm, and the resonant frequency is 150 Hz;

[0058] In the partitioned cavity layer 5, the front airbag group 501 (8 airbags, each with a volume of 50cm³, made of TPU); the middle airbag group 502 (12 airbags, each with a volume of 40cm³); the rear airbag group 503 (4 airbags, each with a volume of 60cm³); and the miniature air pump 504 has a maximum output pressure of 2.0 bar and a flow rate of 5L / min.

[0059] Based on the above data, the sound insulation and noise reduction of the main body 1 of the roof during vehicle operation are as follows:

[0060] First, the vehicle speed sensor collects the vehicle speed in real time with a sampling period of 0.1s, the embedded piezoelectric film 301 collects the roof vibration signal (frequency range 20-2000Hz), and the in-vehicle microphone collects the noise signal (frequency range 20-2000Hz).

[0061] The DSP module performs Fourier transform (FFT) on the collected vibration and noise signals to extract feature frequencies and amplitudes, thereby determining whether the noise type is wind noise or vibration noise, and whether the intensity level is low / medium / high.

[0062] When the vehicle speed is greater than 80 km / h and the high-frequency wind noise (800-2000 Hz) amplitude is greater than 65 dB, the drive motor 203 starts and drives the adjustable spoiler 205 to deploy via the reduction gear set 207 (reduction ratio 15:1). The deployment angle is... =0.002 × vehicle speed (e.g., when the vehicle speed is 100 km / h) =20°, at 120km / h =24°); at the same time, the micro air pump 504 is activated, adjusting the pressure of the front airbag group 501 to 1.5 bar, the middle zone to 1.2 bar, and the rear zone to 1.0 bar, in order to enhance the rigidity of the roof;

[0063] When the amplitude of low-frequency vibration noise (100-300Hz) is greater than 60dB, the active noise reduction layer 3 is activated, and the miniature speaker 302 emits a reverse sound wave with an amplitude of 1.05 times the amplitude of the collected noise and a phase difference of 180° to achieve active cancellation.

[0064] When the vehicle speed is ≤60km / h, the adjustable spoiler 205 automatically retracts into the placement slot 206, and the airbag pressure drops to 0.8bar, reducing energy consumption while ensuring the softness of the innermost interior layer 6 of the roof body 1.

[0065] Compared to traditional sound insulation and noise reduction structures (ordinary cold-rolled steel roof panels, single-density polyurethane foam layers, and ordinary polyester fiber cotton), for the same vehicle model, under the same high-speed wind noise (100km / h, 800-2000Hz) and structural resonance noise (100-300Hz), the sound insulation and noise reduction structure in this embodiment has the following improvement effects:

[0066] Test Project Traditional sound insulation and noise reduction structure The sound insulation and noise reduction structure of this invention Improvement effect High-speed wind noise 72dB 58dB 14dB reduction Structural resonance noise 65dB 55dB Reduced by 10dB drag coefficient 0.32 0.28 Reduced by 12.5% Energy consumption per 100 kilometers 6.8L 6.5L Decrease by 4.4%

[0067] Example 4: Targeting SUVs in urban road conditions and rain / snow weather

[0068] This study addresses engine vibration noise (50-150Hz) and road bump vibration noise (100-250Hz) in congested urban traffic (vehicle speed 0-60km / h), as well as rain noise (2000-5000Hz) in rainy and snowy weather.

[0069] In the outer roof panel 2, the microporous sound-absorbing coating 201 is made of water-based polyurethane + 300nm sound-absorbing ceramic microspheres, with a thickness of 0.6mm and a hydrophobic rating of IPX7; the adjustable spoiler wing 205 is made of glass fiber reinforced composite material, with a length of 90cm and a width of 14cm; the eddy current generator 202 is a triangular protrusion with a height of 3mm, a spacing of 6cm, and a quantity of 18.

[0070] In the active noise reduction layer 3, the embedded piezoelectric film 301 is made of PVDF material, with a thickness of 0.12mm, an arrangement spacing of 22cm, and a quantity of 10 pieces; the miniature speaker 302 has a diameter of 12mm, a power of 3W, an arrangement spacing of 22cm, and a quantity of 10 pieces; the DSP control module has a sampling rate of 96kHz and a delay of ≤3ms.

[0071] In the multi-band sound-absorbing layer 4, the high-density polyurethane layer 401 has a density of 75 kg / m³ and a thickness of 10 mm; the open-cell foam layer 402 is melamine-formaldehyde foam with a gradient density of 80→50→15 kg / m³ and a total thickness of 25 mm; the Helmholtz resonant cavity plate 403 has 350 resonant cavity units 4031, a cylindrical cavity 4032 with a diameter of 18 mm and a height of 22 mm, a neck tube 4033 with a diameter of 4 mm and a length of 10 mm, and a resonant frequency of 120 Hz;

[0072] In the partitioned cavity layer 5, the front airbag group 501 consists of 8 airbags, each with a volume of 60cm³, made of TPU material, and integrates a humidity sensor; the middle airbag group 502 consists of 12 airbags, each with a volume of 50cm³; the rear airbag group 503 consists of 4 airbags, each with a volume of 70cm³; the micro air pump 504 has a maximum output pressure of 2.2 bar and a flow rate of 6L / min.

[0073] Based on the above data, the sound insulation and noise reduction of the main body 1 of the roof during vehicle operation are as follows:

[0074] The vehicle speed sensor samples the environment with a sampling period of 0.1s; the embedded piezoelectric film 301 in the active noise reduction layer 3 collects vibration signals; the in-vehicle microphone collects noise signals; the humidity sensor samples the humidity on the roof; and the road condition sensor obtains the current status of whether it is congested or smooth through the vehicle CAN bus.

[0075] Then, the fuzzy logic algorithm of the Mamdani reasoning method is used to identify the scene and determine whether it is urban congestion, urban smooth traffic, or rainy / snowy weather.

[0076] In urban congestion scenarios: the main focus is on suppressing engine vibration noise (50-150Hz). At this time, the miniature speaker 302 inside the active noise cancellation layer 3 is activated, which emits reverse sound waves. Multiple resonant cavity units 4031 of the Helmholtz resonant cavity plate 403 work together to absorb the noise. The airbag pressure in the partitioned cavity layer 5 is adjusted to 0.9 bar by the miniature air pump 504 to ensure the softness of the interior.

[0077] In urban traffic scenarios, it is necessary to balance road vibration noise (100-250Hz) and medium-speed wind noise (500-1000Hz). At this time, the drive motor 203 drives the rotating rod 204 to rotate, which unfolds the adjustable spoiler 205. The unfolding angle of the adjustable spoiler 205 is 205. =0.001 × vehicle speed (at 60km / h) =6°), the open-pore foam layer 402 located in the multi-band sound-absorbing layer 4 absorbs mid-frequency noise, and the airbag pressure in the partition cavity layer 5 is adjusted to 1.0 bar by the micro air pump 504;

[0078] In rainy or snowy weather: the microporous sound-absorbing coating 201 on the outer layer of the roof panel 2 works in conjunction with the hydrophobic coating of the interior to suppress rain noise (2000-5000Hz). The humidity sensor inside the vehicle triggers a fine adjustment of the airbag pressure, and the micro air pump 504 starts, making the airbag 0.1 bar higher than normal to prevent condensation.

[0079] Compared to traditional sound insulation and noise reduction structures (ordinary cold-rolled steel roof panels, single-density polyurethane foam layers, and ordinary polyester fiber cotton), for the same vehicle model, under the same engine vibration noise (50-150Hz), rain noise (2000-5000Hz), and road bump vibration noise (100-250Hz), the sound insulation and noise reduction structure in this embodiment has the following improvement effects:

[0080] Test Project Traditional sound insulation and noise reduction structure The sound insulation and noise reduction structure of this invention Improvement effect Engine vibration noise 63dB 52dB 11dB reduction Rain noise 78dB 62dB 16dB reduction Road bumps, vibrations, and noise 68dB 56dB 12dB reduction

[0081] The algorithms in Embodiments 3 and 4 above employ FFT spectrum analysis, LMS adaptive filtering, and fuzzy logic scene recognition algorithms. The noise test data is based on GB / T18697-2002 "Acoustics - Measurement Method for In-Vehicle Noise", and is obtained in a professional semi-anechoic chamber and actual road tests. The drag coefficient and energy consumption data are verified through wind tunnel tests and real vehicle road tests, and meet industry testing standards.

Claims

1. A sound insulation and noise reduction structure for a car roof, comprising a roof body (1), characterized in that: The main body of the roof (1) is provided with, from top to bottom, an outer roof panel (2), an active noise reduction layer (3), a multi-band sound absorption layer (4), a partitioned cavity layer (5), and an interior trim attachment layer (6). An adjustable spoiler wing (205) is provided at one end of the outer side of the outer roof panel (2). Multiple eddy current generators (202) are provided at equal intervals at the top of the adjustable spoiler wing (205). Embedded piezoelectric films (301) and miniature speakers (302) are provided at equal intervals inside the active noise reduction layer (3). The multi-band sound absorption layer (4) is arranged in a gradient. The multi-band sound absorption layer (4) is provided with a high-density polyurethane layer (401), an open-cell foam layer (402), and a Helmholtz resonant cavity plate (403) from top to bottom. The partitioned cavity layer is provided with... The layer (5) is divided into three zones. The partition cavity layer (5) includes a front airbag group (501), a middle airbag group (502), and a rear airbag group (503). A miniature air pump (504) is provided in the middle of the side of the front airbag group (501) away from the middle airbag group (502). A main pipe (505) is provided at the output end of the miniature air pump (504). A branch pipe (506) is provided at the position where the main pipe (505) connects the front airbag group (501), the middle airbag group (502), and the rear airbag group (503). A smart pressure regulating valve (508) is provided at the connection between the branch pipe (506) and each airbag. The interior attachment layer (6) is composed of environmentally friendly microfiber fabric.

2. The sound insulation and noise reduction structure for a car roof according to claim 1, characterized in that: The main body (1) of the roof is provided with a placement groove (206) at the position of the adjustable spoiler (205). The bottom and sides of the placement groove (206) are provided with sealing strips (208). A rotating rod (204) is provided at the connection between one side of the adjustable spoiler (205) and the placement groove (206). One end of the rotating rod (204) is provided with a drive motor (203). The drive motor (203) is located inside the outer panel (2) of the roof.

3. The sound insulation and noise reduction structure for a car roof according to claim 2, characterized in that: A reduction gear set (207) is provided between the output shaft of the drive motor (203) and the rotating rod (204), and the reduction ratio of the reduction gear set (207) is 10:1 to 20:

1.

4. The sound insulation and noise reduction structure for a car roof according to claim 1, characterized in that: The front airbag assembly (501) is located on the side of the main body of the roof (1) near the adjustable spoiler (205), and the deployment angle of the adjustable spoiler (205) is towards the rear airbag assembly (503).

5. The sound insulation and noise reduction structure for a car roof according to claim 4, characterized in that: The front airbag group (501) has 8 airbags, the middle airbag group (502) has 12 airbags, and the rear airbag group (503) has 4 airbags. The front airbag group (501), the middle airbag group (502), and the rear airbag group (503) are equipped with exhaust pipes (507) on both sides near the main body of the roof (1).

6. The sound insulation and noise reduction structure for a car roof according to claim 1, characterized in that: The outer surface of the roof panel (2) is provided with a microporous sound-absorbing coating (201).

7. The sound insulation and noise reduction structure for a car roof according to claim 1, characterized in that: The Helmholtz resonant cavity plate (403) is composed of a plurality of regularly arranged resonant cavity units (4031), each of the resonant cavity units (4031) including a cylindrical cavity (4032) and a neck tube (4033) communicating with the cavity.

8. The sound insulation and noise reduction structure for a car roof according to claim 1, characterized in that: The open-cell foam layer (402) is made of gradient density melamine-formaldehyde foam, with its density decreasing from 80 kg / m³ to 15 kg / m³ from top to bottom.

9. The sound insulation and noise reduction structure for a car roof according to claim 8, characterized in that: The density of the high-density polyurethane layer (401) is 60-80 kg / m³.

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