| The planetary gear transmission system has the characteristics of complex structure,large bearing capacity,and accurate transmission,and it is also widely used in complex engineering equipment.Due to the influence of internal excitation and nonlinear factors of planetary gears in the transmission process,the fatigue life of the planetary gear transmission system will be greatly affected during long-term operation.In addition,with the further advancement of scientific research,people have higher requirements for the prediction of the transmission performance and fatigue life of planetary gears.Therefore,it is very necessary to study the dynamic characteristics of the gear system and the fatigue life analysis of the gears.This paper takes the NGW single-stage planetary gearbox transmission system as the research object,and obtains the dynamic meshing force of the planetary gear system by analyzing the rigid-flexible coupling hybrid dynamic model of the gear transmission system.And the accuracy of the rigid-flexible coupling dynamics model is verified through experiments.Then the dynamic meshing force of the gear pair is converted into the load spectrum of the gear fatigue life,and finally the gear is estimated based on the linear accumulation criterion,and compared with the gear fatigue life result based on the finite element method.The main research contents of this paper are as follows:(1)Considering the flexibility of the gear housing and the ring gear,the timevarying meshing stiffness of the gear,the bearing support stiffness,and the tooth backlash,a rigid-flexible coupling dynamic model of the planetary gear transmission system is established.By solving the rigid-flexible coupling model,the dynamic response of the planetary gear transmission system is obtained.The theoretical meshing stiffness was compared with the meshing stiffness extracted from the simulation,the accuracy based on the time-varying meshing stiffness was determined,and the dynamic meshing force change rule of the gear under different tooth backlash was analyzed.The vibration response of the cabinet caused by the internal excitation is solved,and the position with larger vibration response amplitude is selected for comparative analysis.And by carrying out the gearbox dynamic response experiment,the simulation results are compared with the experiment,and the accuracy of the rigid-flexible coupling dynamic model of the gearbox is verified.(2)For the planetary gear transmission system,the dynamic contact finite element model of the planetary gear is established under the condition of considering the real contact stiffness.It is solved by using finite element software,and important performance indicators such as contact stress and bending stress in the dynamic contact process of planetary gears are extracted,and discussed and analyzed.The stress distribution characteristics of the meshing area of single and double teeth in different gear pair tooth profile directions are analyzed and compared.On the basis of analyzing the dynamic contact analysis of planetary gears,the changes of gear contact characteristics under different friction coefficients are analyzed,and the changes in the single and double tooth areas of different gear pairs and the stress changes in the direction of the nodal tooth line under different loads are discussed.(3)The dynamic meshing force of the gear pair obtained by the solution of the rigid-flexible coupling model is converted into a fatigue load spectrum,combined with the P-S-N curve of the gear material,and then based on the linear cumulative damage model,the fatigue life of the planetary gear transmission system is estimated,and the theoretical calculation is The results are compared and analyzed with the results of fatigue life calculated based on the finite element method. |
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