Efficiency Analysis&Optimization On The Gear Box Of New Energy Vehicles In-wheel Drive System

New energy vehicles use new clean energy to replace conventional petroleumresources as automotive power, which are the development trend of the auto industryin the future, because of the high energy efficiency and low environmental pollution.In-wheel drive system is a unique driven approach of new energy vehicles, and its thelevel of transmission efficiency has a critical influence on the energy utilization of thevehicles.The development situation of the in-wheel drive at home and abroad issummarized, the special gear box for in-wheel drive system is analyzed and optimizedin this paper. Four different forms of power loss of the gearbox are studied, and basedon the research the total efficiency formula is proposed and the parameters of the gearbox on the aspect of the efficiency are optimized.Firstly, through the study of the meshing process of the spur gears, a simplifiedthinking is proposed, which is the average efficiency instead of the calculatedefficiency of the meshing spur gear. Therefore, the effects of overlappingcharacteristics on the efficiency calculation is moved, the formula of the spur gearsmeshing efficiency is deduced by using the integration method, and the accuracy of theformulas is verified by the data analysis. Secondly, following the computing ideas ofthe spur gear meshing efficiency, the relationship between the different designparameters and the meshing efficiency is obtained by the formulas deduced by usingthe integration method. The wheel drive system gear box of the new energy vehicles isa high speed gear box, and the loss of churning and wind resistance are large relatively.The churning, wind resistance and bearing power loss principles of the gear box areanalyzed theoretically, and a variety of formulas are summarized. The power losseffects with different working environment parameters are analyzed by usingMATLAB software.The power loss specific process of the gearbox is described under the study of theprevious, the overall formula of the efficiency is presented, the efficiency effects withdifferent design parameters and working environment are obtained, and the proportionof different loss forms in the total power loss is analyzed, which shows that thechurning losses may account for about50%, the meshing and bearing losses are higher than20%, and the loss of wind resistance is less than10%.Finally, the design of helix angle of the gear box is optimized, which shows thatthe gearbox efficiency is increased by1.35%approximately compared with theprevious, and the efficiency values in different working environments between theprevious and optimized gear boxes are analyzed.