CN112550180A

CN112550180A - Noise-reduction interior trim system for special vehicle cab

Info

Publication number: CN112550180A
Application number: CN202011360545.5A
Authority: CN
Inventors: 鞠龙华; 王安斌; 高晓刚; 李炜; 刘浪
Original assignee: Shanghai University of Engineering Science
Current assignee: Shanghai University of Engineering Science
Priority date: 2020-11-27
Filing date: 2020-11-27
Publication date: 2021-03-26

Abstract

The invention relates to a noise reduction interior trim system for a special vehicle cab, which comprises any one or combination of a sound absorption interior trim structure, a high-strength multilayer composite floor structure and a sound absorption and insulation structure of an engine cabin; the roof sound absorption structure sequentially comprises a first sound absorption material and a first protective surface layer from inside to outside, and the first sound absorption material is attached to the roof; the high-strength multilayer composite floor structure sequentially comprises floor leather, a damping composite interlayer structure and a second sound absorption material from top to bottom, and the second sound absorption material is arranged by being attached to the ground; the engine compartment sound absorption and insulation structure sequentially comprises a third sound absorption material, a damping steel plate, a fourth sound absorption material and a second protective surface layer from inside to outside, wherein the third sound absorption material is attached to the inner side of the compartment plate, and the fourth sound absorption material is attached to the outer side of the compartment plate. Compared with the prior art, the invention has wide noise reduction frequency range and wide application range.

Description

Noise-reduction interior trim system for special vehicle cab

Technical Field

The invention relates to the technical field of vehicle noise control, in particular to a noise reduction interior trim system for a special vehicle cab.

Background

At present, most special vehicle cabs have the problem of different degrees of poor noise environments, abnormal sound occurs under a certain vehicle speed, or the average value of noise is too large under most working conditions, so that the condition is caused by various reasons. For special vehicles, the engine power is high, and is mostly exposed outside and close to the cab, so that the noise directly transmitted to the cab through air is excessive; the axles and the suspensions are numerous, and the problem of mode matching of the whole vehicle is not considered deep and detailed enough; the cab system is unreasonable in design, the structural mode and the acoustic cavity mode are easy to resonate and generate rolling, and in addition, the use of sound absorption and insulation materials is inexperienced.

From the characteristic analysis of a noise source, the special vehicle is used as a complex electromechanical system, the axles are numerous, the vibration transmission path is complex, and the main factors influencing the noise in the cab are variable. When the vehicle runs at a low speed, a power system and a transmission system are main vibration sources and noise sources of a cab, and are mostly concentrated in 200Hz and belong to low-frequency noise in terms of frequency band distribution; along with the increase of the vehicle speed, tire noise caused by road excitation, transmission noise of a speed change differential and braking noise are prominent, the range of 200-1000 Hz is taken as the main factor, and the noise belongs to intermediate frequency noise; during high-speed running, the wind-to-noise ratio is increased, and the wind-to-noise ratio becomes a main noise source in a cab, is concentrated in the range of 1000-5000 Hz and belongs to high-frequency noise.

In view of the progress of research, Noise, Vibration and Harshness (NVH) have become popular areas for research in the automobile industry in recent years, so that not only passenger car companies are engaged in developing NVH performance, but also commercial car NVH performance is gaining more and more attention from various automobile enterprises. The noise and vibration requirements of governments and enterprises in various countries for special off-road vehicles are also becoming more and more stringent. Most of domestic research objects in the noise field are passenger vehicles, NVH performance research on special vehicles is less, and certain gap exists between the vibration and noise level requirements of domestic related vehicles, so that the special vehicles become a limiting factor for restricting the development of body structures of the special vehicles. In addition, under the noise environment, the passengers are stressed, easy to fatigue, irritated in mood and not concentrated in attention, and are more likely to cause adverse reactions such as dizziness, distraction, nausea and the like and even cardiovascular and cerebrovascular diseases when being in the noise environment for a long time. The special off-road vehicle mostly runs on the terrain with poor road conditions or no road, the possible types of the encountered excitation are many, the vibration and the noise in the cab are serious, and the influence of the noise in the special vehicle on soldiers in battle is fatal. Therefore, the development of technical research related to the NVH of the special vehicle cab has very important significance in the aspects of economic value and national benefits.

Disclosure of Invention

The object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to provide a noise-reducing interior trim system for a special vehicle cab.

The purpose of the invention can be realized by the following technical scheme:

a noise reduction interior decoration system for a special vehicle cab comprises any one or combination of more of sound absorption structure interior decoration, a high-strength multilayer composite floor and engine compartment sound absorption and insulation structure interior decoration;

the sound absorption structure interior decoration comprises a first sound absorption material and a first protective surface layer from inside to outside in sequence, and the first sound absorption material is arranged by being attached to the wall surface of the cab;

the high-strength multilayer composite floor sequentially comprises floor leather, a composite sandwich floor, a constraint damping plate and a second sound absorption material from top to bottom, wherein the second sound absorption material is arranged by being attached to the ground;

the interior decoration of the sound absorption and insulation structure of the engine compartment sequentially comprises a third sound absorption material, a damping steel plate, a fourth sound absorption material and a second protective surface layer from inside to outside, and the third sound absorption material is attached to the compartment plate.

Preferably, the first protective layer is made of a light perforated metal plate or a composite plate.

Preferably, the diameter of the through hole on the first protective layer is 2-3 mm.

Preferably, the perforation rate on the first protective layer is 20-30%.

Preferably, the first sound absorbing material comprises a porous sound absorbing material or a resonant sound absorber.

Preferably, the splicing position of the high-strength multilayer composite floor is sealed by a sealing strip or spliced by a tongue-and-groove.

Preferably, the bending strength of the high-strength multilayer composite floor is more than or equal to 100MPa, the bending modulus is more than or equal to 40MPz, and the weighted sound insulation quantity is more than 35 dB.

Preferably, the flooring in the high-strength multi-layered composite flooring structure comprises rubber flooring.

Preferably, the second sound-absorbing material comprises a porous sound-absorbing material or a resonant sound-absorbing body.

Preferably, the third sound-absorbing material and the fourth sound-absorbing material comprise porous sound-absorbing materials or resonant sound-absorbing materials.

Compared with the prior art, the invention has the following advantages:

(1) the interior trim system for noise reduction of the special vehicle cab has the advantages of high noise reduction amount, high reliability, convenience in maintenance and low cost, can effectively overcome the defects in the prior art, is simple in structure, can widen the noise reduction frequency band compared with the existing interior trim, and is convenient to mount and dismount, strong in adaptability and high in reliability.

(2) Aiming at the problems of serious insufficient sound insulation of the floor of the vibration corridor, limited thickness of the floor and the like, in the design of the high-strength multilayer composite floor, sound absorption is carried out by adopting a sound absorption material, and meanwhile, a high sound insulation structure of a composite sandwich floor and a constraint damping plate is adopted, so that the noise penetrating into a cab through the floor can be effectively inhibited, and the average sound insulation of the structure in the frequency range of 50-3150 Hz can reach 28.9dB through numerical simulation calculation.

(3) The sound absorption and noise reduction performance of the vehicle is higher in the closed noise of the inner surface layer of the vehicle, so that in the scheme design, the sound absorption structure inner decoration is adopted, the heat-resistant acoustic metamaterial is adopted in the power generation cabin, the average sound absorption of the two materials at 300-1500 Hz can reach 0.5, the noise in the power generation cabin can be reduced by 3dB through sound absorption and noise reduction, and the noise in the cab can be reduced by 2 dB.

Drawings

FIG. 1 is a schematic structural view of an interior trim of a sound absorption and insulation structure of an engine compartment according to the present invention;

FIG. 2 is a schematic structural view of the interior of the sound absorbing structure of the present invention;

FIG. 3 is a schematic structural view of the high-strength multi-layered composite floor according to the present invention;

FIG. 4 is an enlarged view of a circled portion of FIG. 3;

FIG. 5 is a plot of sound absorption coefficient for a 50mm thick melamine acoustic foam;

in the figure, (1) is a nail; (2) is a perforated structural plate; (3) is melamine sound absorbing foam; (4) is a power compartment clapboard; (5) is a damping sound insulation plate; (6) is a constraint steel plate; (7) is an acoustic metamaterial; (8) is a detachable fixing screw; (9) an aluminum alloy pressing strip; (10) the inner square tube is fixed with the top; (11) is a rivet connection; (12) is an L-shaped bent edge; (13) fixing the touch nails; (14) is a vehicle body frame; (15) m6 flat-head self-tapping screw and gasket; (16) is melamine sound absorbing foam; (17) is a micro-perforated acoustic panel; (18) splicing the tongue-and-groove of the plate; (19) fixing screws for the floor; (20) is a constraint steel plate; (21) is a damping sound-proof board; (22) is a vehicle body framework; (23) is a foamed aluminum sandwich floor; (24) is made of polyimide sound-absorbing and heat-insulating cotton and high-density fireproof cloth; (25) splicing the tongue-and-groove of the floor board; (26) fixing screws for the floor; (27) is floor leather; (28) is a constraint steel plate; (29) is a damping sound-proof board; (30) is a foamed aluminum sandwich floor; (31) is polyimide foam; (32) is a vehicle body framework.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. Note that the following description of the embodiments is merely a substantial example, and the present invention is not intended to limit the application or the use thereof, and is not limited to the following embodiments.

Examples

the sound absorption structure interior sequentially comprises a first sound absorption material and a first protective layer from inside to outside, and the first sound absorption material is arranged to be attached to the wall surface of the cab;

the high-strength multilayer composite floor sequentially comprises floor leather, a damping composite sandwich floor and a second sound absorption material from top to bottom, wherein the second sound absorption material is attached to the ground;

The first protective layer is made of a light perforated metal plate or a composite plate.

The diameter of the through hole on the first protective layer is 2-3 mm.

The perforation rate on the first protective layer is 20-30%.

The first sound absorbing material comprises a porous sound absorbing material or a resonant sound absorber.

The splicing position of the high-strength multilayer composite floor is sealed by a sealing strip or spliced by a tongue-and-groove.

The bending strength of the high-strength multilayer composite floor is more than or equal to 100MPa, the bending modulus is more than or equal to 40MPz, and the weighting sound insulation quantity is more than 35 dB.

The flooring in the high-strength multi-layer composite flooring structure comprises rubber flooring.

The second sound absorbing material includes a porous sound absorbing material or a resonant sound absorber.

The third sound absorbing material and the fourth sound absorbing material comprise porous sound absorbing materials or resonance sound absorbers.

Wherein, porous sound absorbing material inhales the sound foam like the melamine, can also be glass wool, mineral wool, rock wool and fibre material, and the resonance sound absorber is if adopting cavity resonance sound absorbing structure, and resonance sound absorbing structure's sound absorption principle is: when the frequency of the sound wave is consistent with the natural vibration frequency of the resonance sound absorption structure, resonance occurs, the sound wave excites the resonance sound absorption structure to generate vibration, and the amplitude is maximized, so that the sound energy is consumed, and the purpose of sound absorption is achieved.

Specifically, the method comprises the following steps:

1. sound absorption structure interior trim

The sound absorption structure interior trim is mainly used for positions such as the outer surface of a power cabin, a vehicle roof and the like, and adopts different sound absorption measures according to different noise source characteristics and functional requirements. The scheme of the part mainly aims at improving the sound absorption coefficient of the material so as to reduce the indoor reverberation noise and improve the working sound environment of personnel, and the specific implementation scheme is as follows:

the first sound absorbing material of sound absorbing structure interior trim adopts melamine to inhale the sound foam, and first visor layer adopts the perforated plate, perforation diameter (about 2 ~ 3mm), perforation rate (20 ~ 30%), through optimizing behind perforation diameter and the perforation rate, can realize high sound absorption performance to the specific frequency channel, arranges the scheme and see figure 2. The interior decoration of the sound absorption structure has the following performance characteristics:

1) high sound absorption coefficient

The melamine sound absorption foam has the advantages that the interior of the open pore is filled with fine gaps and a semi-open pore structure, so that a large amount of incident sound wave energy can be absorbed, the sound waves are attenuated, through tests, the sound absorption coefficient of the melamine foam with the thickness of 30mm in the middle and high frequency range of 1000-2000 Hz has an obvious noise peak value, is close to 1.0 and is far higher than that of other sound absorption materials, and is shown in figure 5.

2) The construction is simple and quick, and the veneer can be repeatedly disassembled and assembled

In the construction process, the melamine foam is provided with the pressure-sensitive adhesive, can be directly cut according to the size of a construction object, then the release paper is torn, and the melamine foam can be directly bonded or can be reinforced in an auxiliary mode of nail collision bonding. In addition, the larger edge gap needs to be coated with sealant. The size of the perforated plate of the first protective layer can be customized according to the size on site or prefabricated in advance, and the perforated plate is convenient to cut on site. The panel floats on the sound-absorbing foam, the splicing opening is fixed by an aluminum pressing strip, and the aluminum pressing strip is fixed on the bulkhead through a detachable nut and can be detached repeatedly.

3) Environment-friendly sound-absorbing material made of material

The melamine foam does not contain fine fiber emission, does not have glass fiber pulverization or flying in the cutting and construction processes, does not contain halogen or heavy metal flame retardant, has unique chemical stability due to a stable chemical structure and a crosslinking system, and completely meets the national green and environment-friendly standards in the fields of indoor decoration, daily necessities, noise reduction of vehicles and the like.

4) The sound-absorbing material is flame-retardant, fireproof, heat-insulating and high-temperature-resistant

The melamine foam can reach the flame retardant grade of B1 without adding any flame retardant, and a compact coke layer is formed on the surface of a combustion body after the melamine foam contacts open fire so as to retard combustion, and the melamine foam has the advantages of no dripping, no toxic smoke, no combustion and self-extinguishing after being away from fire. The material is suitable for working at the working condition of 200-240 ℃ for a long time, and does not have decomposition and deformation phenomena below 530 ℃.

2. High-strength multi-layer composite floor

The floor is one of main transmission channels of vibration and noise, is a part needing to be mainly protected and treated, and the main structure of the floor is adopted from top to bottom: leather, a composite sandwich floor, a constraint damping plate and a second sound absorption material, which are shown in figures 3 and 4. Wherein every part of floor part can all leave the factory and customize, and the whole preparation is installed as a module scene, also can divide into three parts and install respectively, and the flexibility is higher. The scheme has the following advantages:

1) high damping multilayer composite structure, the sound insulation performance is excellent:

the composite sandwich floor adopts closed-cell foamed polyurethane material, and the closed gap can effectively isolate the transmission of medium-high frequency sound waves. In order to avoid the occurrence of sound coincidence effect (sound leakage phenomenon) caused by modal resonance of the whole structure, the surface is pasted with a high-damping vibration attenuation material, so that the whole damping loss and sound insulation capability can be improved, and the vibration energy caused by sound waves is effectively converted into heat energy to be dissipated. Meanwhile, the multilayer interface can effectively increase the repeated reflection and refraction of sound waves, increase the sound transmission distance and enhance the sound insulation performance.

2) The construction is high in efficiency, convenient and flexible in operation:

the operation method and the process of the light floor are basically consistent with the operation mode of wood, and the conventional electric tool can be used for cutting, drilling, trimming and the like. The size of the plate can be cut on site and can also be customized after leaving factory. The lap joint of panel reservation is opened mouthful, and the concatenation is convenient quick, can prevent again that the sound leakage from. After the damping plate is cut, the damping plate is directly adhered to the composite sandwich floor by the brush glue, and the whole construction is rapid and the construction efficiency is high.

3. Sound absorption and insulation structure of engine compartment

The engine compartment partition is one of main transmission channels of vibration and noise, is a part needing to be mainly subjected to protection treatment, and adopts the following scheme: including third sound absorbing material, damping steel sheet, fourth sound absorbing material, second armor, as shown in figure 1, this scheme main advantage, as follows:

1) the baffle increases the damping steel sheet, effectively avoids the sound wave to arouse that panel resonance leads to the emergence of coincide effect (lou) phenomenon:

because the noise in the engine compartment is extremely high, and the compartment plate is a thin-wall steel component, the damping loss of the compartment plate is very low, the structural resonance phenomenon is easily caused under the excitation of sound waves, the secondary structural noise of the compartment plate is excited, and the compartment plate loses the sound insulation capability in the resonance frequency band. Therefore, the high-performance constraint damping plate structure is laid on the surface, vibration energy can be efficiently converted into heat energy to be dissipated, the structural noise radiation of the partition plate is reduced, and in addition, the damping plate and the constraint steel plate play a role in increasing the sound insulation energy.

2) The sound absorption metamaterial is hung, medium and low frequency noise is efficiently absorbed, and noise transmission is suppressed at the source:

because the internal noise of the engine is extremely high, and the noise also has a relatively obvious response peak value in a medium-low frequency band, the problem of medium-low frequency noise is difficult to solve by a common sound absorption member under the limited thickness, therefore, an acoustic metamaterial is hung towards one side of the engine, and the low-frequency resonance sound absorption is realized by utilizing the special structural structure of the metamaterial, so that the direct radiation air noise of the engine is reduced, the noise energy is attenuated from the source, and the noise transmission to the periphery is inhibited. The acoustic metamaterial is an existing material, and the material per se is not required to be protected by the invention.

3) The construction is efficient and quick:

the structural size of the constrained damping plate can be randomly prefabricated and formed in advance or cut on site, and the constrained damping plate is formed by brushing glue on site and bonding. The acoustic metamaterial is high in structural strength, a small number of supporting screws can be welded in an auxiliary mode to prevent the acoustic metamaterial from transversely collapsing, and the acoustic metamaterial can be supported by the structural strength of the acoustic metamaterial in the vertical direction.

The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments may be implemented in other various manners, and various omissions, substitutions, and changes may be made without departing from the technical spirit of the present invention.

Claims

1. A noise reduction interior trim system for a special vehicle cab is characterized by comprising any one or combination of more of a sound absorption interior trim structure, a high-strength multilayer composite floor and an engine compartment sound absorption and insulation structure interior trim;

2. The noise reduction interior trim system for a special vehicle cab according to claim 1, wherein the first facing layer is a lightweight perforated metal sheet or a composite sheet.

3. The noise reduction interior trim system for the cab of the special vehicle as claimed in claim 2, wherein the diameter of the through hole in the first protective layer is 2-3 mm.

4. The noise reduction interior trim system for the cab of the special vehicle as claimed in claim 2 or 3, wherein the first protective layer has a perforation rate of 20-30%.

5. A noise reducing interior trim system for a special vehicle cab as claimed in claim 1 wherein the first sound absorbing material comprises a porous sound absorbing material or a resonant sound absorber.

6. The noise reduction interior trim system for the special vehicle cab according to claim 1, wherein the splicing position of the high-strength multilayer composite floor is sealed by a sealing strip or spliced by a tongue and groove.

7. The noise reduction interior decoration system for the special vehicle cab is characterized in that the bending strength of the high-strength multilayer composite floor is larger than or equal to 100MPa, the bending modulus of the high-strength multilayer composite floor is larger than or equal to 40MPz, and the weighted sound insulation quantity is larger than 35 dB.

8. The noise reducing interior trim system for a special vehicle cab of claim 1, wherein the flooring in the high strength multi-layer composite floor structure comprises rubber flooring.

9. The noise reducing interior trim system for a special vehicle cab of claim 1, wherein the second sound absorbing material comprises a porous sound absorbing material or a resonant sound absorbing material.

10. The noise reducing interior trim system for a special vehicle cab of claim 1, wherein the third and fourth sound absorbers comprise porous sound absorbers or resonant sound absorbers.