Vibration And Noise Analysis Of Two Speed Automatic Mechanical Transmission Shell

As the most important traffic tools,the vehicle provides us comfortable and easy service.However,with the rapid development of the automobile industry and the increasing production and sales of automobiles,the problems of environmental pollution and renewable resources are becoming more and more prominent.Energy saving and environmental protection become the focus of different country.Subsequently,pure electric vehicles attracted people's attention,with zero emissions and low noise characteristics.Research and promotion of pure electric vehicle-related technologies has become the focus among the world's automotive industry.The NVH(noise,vibration and harshness)performance of automobile catches more and more attention by the consumers.As for the pure electric vehicles,the transmission plays a very important role of performance and produce noise and vibration during operation.During the power transmitting process,the transmission itself will produce vibration,causing other parts vibrating at the same time,thereby affecting the ride comfort of the vehicle.The transmission housing is the basic part of the transmission,assembling the key components in the transmission and protecting these important parts from working properly.Therefore,it is necessary to study the vibration and noise principle of the transmission case during working process.In this paper,the vibration characteristics and sound radiation prediction of 2AMT house are analyzed to ensure that the box has enough good performance to ensure that the transmission can work normally under certain conditions.At the first place,the structure and working principle of pure electric vehicle 2AMT are studied,and the mechanism of transmission vibration and noise is analyzed.It is found that the varying mesh stiffness,transmitting error between two meshed gears and meshing impact are the key sourc of transmission house noise.House as a key part of the transmission,will be resonant by the shock force of the transmission,resulting in a resonance load in some areas of the transmission housing and causing large deformation.When this part of load exceeds the tensile strength of the material,the shell will occur fracture.This provides a theoretical basis for the vibration and noise reduction of the transmission case.Secondly,the three-dimensional solid model of the gearbox shell is established by software UG in order to analyze the natural vibration mode of the transmission case and the house is simplified reasonably according to the finite element analysis.The finite element model of the 2AMT transmission case is obtained and the natural frequencies and the corresponding modes are obtained by the software ABAQUS.Then,dynamic simulation software ADAMS was used to simulate the drive shaft,and the dynamic response of the load was obtained.In order to analyze the harmonic response of the shell in the next step,the frequency response of the shell under the excitation force was obtained.Finally,the noise radiation simulation of the transmission case is carried out with Virtual.Lab acoustics software,and the simulation results are analyzed briefly.