Analysis Of Dynamic And Static Characteristics Of Pure Electric Mini Bus Planetary Reducer

At present,the environmental pollution is serious and the resources are scarce,while the car consumption of fuel resources and the pollution to the environment are very serious.Therefore,in the automotive industry,electric vehicles will gradually replace the fuel vehicles,becoming the main trend of the development of automobiles.In electric vehicles,the speed reducer is the main power transmission device,speed reducer is mainly composed of gear transmission system and the external box,planetary gear transmission has the advantages of compact structure,stable transmission,high transmission efficiency,large transmission ratio etc.As the core of the speed reducer,the operation of the gear system directly affects the performance of the electric vehicle.With the development of the automobile industry,the transmission power of the speed reducer is increasing,and the gear running speed is faster and faster.The vibration problem of the gear drive system has become an important research topic.After reading a large number of documents and analyzing the research status of gear drive system both at home and abroad.In this paper,take the coaxial double NW planetary gear reducer of an enterprise pure electric mini bus for research objects,and carry out the statics,dynamics and contact of gear surface analysis.Established the 3D solid model of NW planetary gear reducer by using 3D modeling software.Put forward analysis method of gear drive system,and obtained the reduction ratio,the meshing force between gears,the characteristic frequency of transmission system under rated working condition,the contact stress of gear engagement,the strength of input and output shaft.Established the dynamic and static analysis model of planetary gear reducer key components,static analysis of the input shaft,the planetary system,the output shaft and the gear box,and got the equivalent stress of gear and stress distribution,the results meet the requirements of strength and rigidity,can work normally.The modal analysis of the input shaft,planetary gear train and transmission device were carried out,and obtained the first six order natural frequencies and mode shapes,the analysis showed that the natural frequency is far from the characteristic frequency of the system,and no resonance phenomenon occurs.Through the contact analysis of the sun wheel and the planetary gear engagement,got the dynamic contact stress is slightly larger than the static contact stress,and the stress concentration at the sharp corners of the gear tooth.Then the influences of contact performance by different gear backlash were analyzed,which showed that the contact stress of gear is larger with the gear backlash increase.