Analysis And Optimization Of Load Sharing Characteristics Of Shield Machine Planetary Gear Reducer

Planetary gear reducer has many advantages,such as small volume,large transmission ratio and high power density.It is widely used in shield machine drive system.Due to the complex and changeable geological conditions of tunneling,the retarder of shield tunneling machine will frequently encounter extreme conditions such as overload and impact,resulting in uneven load of the retarder,aggravating vibration until failure,and eventually leading to the failure of normal construction of shield tunneling machine,and even leading to major safety accidents.Therefore,it is of great significance for the construction safety and efficiency of shield machine to study the load sharing characteristics of high power density planetary reducer,realize the optimization of structure and parameters,and improve the reliability of reducer.This thesis takes 2K-H three-stage planetary gear reducer as the research object,establishes a three-dimensional model of planetary gear reducer of a shield machine,calculates the load undertaken by all levels of the three-stage planetary gear reducer combined with the actual working conditions,and uses the finite element software Ansys to carry out transient dynamics simulation analysis.It is calculated that the maximum stress of the gear reducer at all levels is 205 MPa,415.4 MPa and 730.2MPa respectively.It is found that the meshing pair of the third stage solar wheel and planet wheel is the most vulnerable to damage.The translation-torsional dynamics equation of the third-stage planetary gear train was established by using the method of centralized parameters.By changing the supporting stiffness,meshing stiffness and inertia load of the system itself,the influence of system parameters on load sharing performance was analyzed,and the variation of load sharing performance under different working conditions was studied.The results showed that the higher the equivalent supporting stiffness,meshing stiffness,inertia load and speed of the gear train,the higher the equivalent supporting stiffness,meshing stiffness,inertia load and speed were.The worse the third stage of planetary gear reducer is,the better the load is.The dynamic analysis software ADAMS was used to set the solar wheel and the planetary frame of the planetary gear reducer,and the MATLAB genetic algorithm toolbox(GA)was used to optimize the planetary gear reducer with the minimum dynamic load coefficient,maximum recombination degree,minimum volume and maximum carrying capacity.By determining the design variables,objective functions and constraint equations,The optimal mathematical model of planetary gear reducer was established,and the parameters of the gear were optimized.After optimizing the parameters of the third stage gear of planetary gear,the dynamic load coefficient was reduced by 2.4%,the contact degree was increased by 0.4%,the volume was reduced by 3.99%,and the carrying capacity of the solar wheel was increased by 3.19%.Finite element model was established for the third stage of the reducer after optimization and transient dynamics analysis was carried out.It was found that the stress of the optimized solar wheel and planet wheel decreased from 730.2 MPa to688.07 MPa.The research results provide a theoretical basis for the optimization design of planetary reducer of shield machine,which has important significance and engineering value for improving its reliability.