Design And Development Of Integrated Electric Drive Axle For Micro Electric Passenger Carby

In recent years,due to the characteristics of light weight and small size,mini and small electric vehicles have accurately captured the market demand for economic and convenient travel.The industrial scale and industrial concentration have been constantly improving,and the product structure has also changed from low-end products to medium and high-end products.As the core components of mini and small electric vehicles,electric drive axle is related to vehicle performance and driving safety.It is conducive to enhance the core competitiveness of enterprises,promote the safety and the sustainable development of new energy vehicles that study the design and development method of mini and small electric drive axle with high-cost performance,high performance and safety.In this paper,the design of high-performance electric drive axle of mini and small car is studied from the aspects of structure selection,scheme design check,CAE analysis and optimization,bench test verification,etc.,and the specific contents are as follows:Firstly,the motor power selection and matching calculation method of reducer speed ratio are summarized based on automobile theory and vehicle driving dynamics research,which provides guidance for quick calculation and selection of motor power and main deceleration ratio in the early stage of design and development.In this paper,according to the power and economic requirements of a mini and small electric vehicle,the driving capacity of the vehicle under different driving conditions is analyzed,and the key parameters of the transmission system such as motor parameters and transmission ratio are matched design research;According to the automobile design and reducer design theory,this paper summarized the verification methods of Axle housing tube specification selection,design of double stage parallel shaft reducer,differential design and half shaft bearing selection and other key parts of the electric drive axle design.And based on the parameters of a mini and small electric vehicle,the parts selection and design check of the electric drive axle were carried out and the 3D structure design was completed.Secondly,based on the dynamic excitation theory of gear system,ROMAX software is used to study the macro-optimization of the gear including gear modulus,spiral angle,pressure angle,displacement coefficient and other parameters.And after the gear macro parameters are determined,the tooth direction and involute direction modification optimization of micro-parameters such as drum quantity,slope and evaluation limit were studied.By comparing and analyzing the transmission error of gear before and after optimization,it is found that the linear transmission error of gear can be improved after macro parameter optimization and micro modification.The variation of the theoretical linear transfer error of the gear tends to zero under the set optimization conditions,which can provide an optimization scheme for improving the gear meshing NVH performance.By comparing the load per unit length,contact fatigue life and bending fatigue life of gears before and after optimization,it is found that the contact spots of gears after optimization are significantly improved,and the safety factor of gear life is improved.Then the CAE analysis constraint loading method of key parts of electric drive axle is summarized.CAE analysis tools are used to analyze and optimize the structure of electric drive axle including axle housing,half shaft strength and stiffness analysis;Strength analysis of reducer casing and differential casing;Reducer bearing fatigue life,reducer housing modal and assembly modal analysis.Finally,the reliability test of the electric drive axle of the miniaturized vehicle was carried out,and the test results were compared with the CAE simulation analysis results.The comparison results show that these analysis methods and evaluation indexes including shell strength and stiffness simulation,reducer housing and differential housing static torsion simulation,half shaft static torsion,reducer gear and bearing fatigue life simulation,have guiding significance in the early development and can quickly verify the feasibility of the design scheme.Then,the NVH test method of electric drive axle deceleration and the calculation method of key rotating parts of the decelerator are summarized.LMS data acquisition equipment is used to collect and analyze the data of the electric drive axle.The analysis results show that the electric drive axle designed in this paper achieves the NVH design target.