Technology Study Of Electrochemical Machining Of Internal Gear On Electric Vehicle Transmission Shaft

The internal gear is the intermediate part between the shaft tube and the universal joint on the transmission shaft of electric vehicle,which is in great demand in the electric vehicle industry.The internal gear is usually made of 20Cr Mn Ti and 40Cr steel.In the process of gear shaping and broaching,the processing efficiency of internal gear is low and the tool wear is large.It is not conducive to improving the efficiency of internal gear processing and reducing the processing cost.Therefore,it is urgent to explore a processing technology to solve the difficulties in the internal gear proce ssing.In view of the problems in the internal gear processing technology of electric vehicles,this paper put forward the experimental exploration of the internal gear processing by using ECM to verify the processing feasibility.And optimize process parameters to improve processing efficiency and reduce processing cost.In this paper,the scheme of ECM internal gear was designed,the cathode and fixture were designed,the difficulties in the ECM of internal gear were studied,and the experimental parameters of the experimental were optimized.The details of the main work are as followed:1.The advantages and disadvantages of the main processing methods of internal gear were analyzed.The difficulties in the ECM internal gears were pointed out.The process of internal gear was simplified into the superposition of multiple teeth machining processes,and the difficult problems in the single teeth machining process was analyzed.According to the requirements of flow field design in ECM,an improved forward flow field model was proposed.The cathode and fixture of ECM were designed,and the cathode structure was optimized by computer simulation technology.After optimization,the current density difference was reduced to 9.36A/cm² of the cathode.The cathode structure was reasonable,stable and reliable.2.By using COMSOL Multiphysics5.0 simulation software,the improved flow field model with forward flow and reverse flow field models were compared in multi-physical field coupling simulation.The gas motion and the flow field characteristics in each flow field models were studied.When inlet pressure was 0.9MPa,by using the improved forward flow field type,the gas content in the corner gap was only 0.91×10^-5.The flow field in the processing area was evenly distributed.It was concluded that the improved forward flow type can effectively promote the uniformity of gas-liquid distribution in the flow field and improve the localization of electrolyte in the processing area.3.The high-speed camera was used to capture the area with poor uniformity of flow field,record the gas movement track and the gas accumulation area.Combined with the experimental results of simulation and analysis,the experimental parameters were evaluated and optimized.The profiles of work piece were inspected after the experiment.Under the condition of improved flow field,the profile of machining gap was reduced254?m,the profile of corner gap was reduced 228?m.Experiments showed the removal amount was even.It was proved that the improved forward flow field model can effectively solve the problem of uneven removal amount in the machining area.4.Through the application of special electrochemical machine tool,the process experiment of internal gear was carried out.By changing the processing voltage,pulse duty ratio,feed rate and other parameters,the influence of processing parameters in the internal gear forming was analyzed.Through a large number of repeatable experiments,the processing parameters was reorganized and analyzed.The parameters of Processing voltage 15V,Pulse duty cycle 50%and the feed rate 1.0mm/min were used to trial produce internal gear to validate conclusion.The results showed that by using the improved flow type and the optimized process parameters can process internal gear effectively and stably.The above work has effectively explored the ECM processing experiment of the internal gear,and it has carried on the targeted research to the processing problems,which has laid the foundation for the subsequent industrial application of the ECM internal gear.