Research On Key Technology Of High Power Density Electric Drive System Design

The electric wrench is a kind of electric power as the power to tighten the high strength bolts the tool,the electric wrench is mainly used in steel installation and so on industry.The electric wrench is operated by the internal planetary gear train system for speed and torque transmission.At present,the efficiency of the domestic electric wrench is generally low,if the installation of the bolt preload is greater,the need for greater motor and input power,not only increased the waste of electricity but also increased the weight of the electric wrench.In this paper,the high power density electric wrench planetary gear train system as the research object,to optimize the analysis.The most widely used in the electric wrench transmission system is the 2K-H planetary gear train,which is optimized for the optimization target with the minimum volume and the maximum transmission efficiency.Firstly,the dynamic characteristics of the planetary gear train are analyzed.The dynamic meshing force of the planetary gear train and the total transmission efficiency of the planetary gear train are simulated by ADAMS software.The dynamic action and the planetary gear Of the total transmission efficiency,to provide the basis for efficiency analysis.Electric wrench as a handheld tool,the weight of the fuselage will have a greater impact on the operator,the weight of the electric wrench is mainly concentrated in the fuselage transmission system,in order to reduce its weight,the need for electric wrench drive system volume calculation.In the past,the calculation of the gear volume is relatively rough,ignoring the impact of the headspace and the gear displacement on the volume.On the basis of the existing research,a new gear volume mathematical model is established according to the gear head gap and displacement.The efficiency of the electric wrench depends mainly on the transmission efficiency of the planetary gear train system.Based on the analysis of the meshing efficiency of single-pair gears,a single-pair variable gear transmission efficiency model is established according to the meshing characteristics of the displacement gears.The single-gear transmission efficiency model is introduced into the 2K-H planetary gear train drive efficiency calculation In the formula,a new 2K-H planetary gear train transmission efficiency model is established.The efficiency of the planetary gear train in the electric wrench is solved by deducing the formulaof efficiency.Through the establishment of the mathematical model of the volume and efficiency of the electric wrench transmission system,the multi-objective optimization of the electric wrench planetary gear train system is carried out by using MATLAB.Taking the parameters of the gear as the design variables,the conditions of the gear contact strength and the bending fatigue strength are taken as constraints.The optimization of the planetary gear train is carried out with the minimum volume and the highest efficiency as the optimization target,the optimization of the planetary gear train is carried out with the minimum volume and the highest efficiency as the optimization target,and the optimization results are verified by simulation.This paper completes the dynamic simulation of the electric wrench planetary gear train system,the establishment of volume mathematical modeling,the establishment of the mathematical model of transmission efficiency,the multi-objective optimization and the simulation results of the simulation.Improve the transmission efficiency of the electric wrench,reduce the overall weight of the electric wrench,and realize the optimal design of the high power density electric wrench transmission system.