The Dynamic Performance Analysis And Optimal Design On The Transplanting Mechanism With Planetary Elliptic Gears

As the direct realization mechanism of transplanting function,the transplanting mechanism with planetary elliptic gears has been deeply studied by various countries.At present,the development of high speed transplanter mechanism has been more mature.The analysis work on its dynamics performance is also crucial.In this paper,the dynamic performance of the transplanting mechanism with planetary elliptic gears is analyzed and the optimization mathematical model is established to conduct optimal design of the transplanting mechanism.The basic parameters of elliptic gears are analyzed,and the idea is based on the joint curve and involute curve of non-circular gear and combine with mathematical calculus method to design elliptic gear.Through Creo and CAXA software,the three-dimensional model of the transplanting mechanism with planetary elliptic gears is established.The dynamic equation of the transplanting mechanism with planetary elliptic gears is established.Considering the load,inertial force,centrifugal force and elastic deformation conditions between the components are deduced.According to Newton’s second law and Darangbel’s principle,the dynamic equations of each component of the transplanting mechanism is established,and then the equations of the system of the transplanting mechanism are deduced.By using MATLAB software to numerical simulation calculation,the dynamic meshing force,meshing stiffness,inertia force,centrifugal force and the load of each gear shaft support bearing are solved.By means of modal analysis,ANSYS Workbench software is used to solve the relationship between natural frequency and output frequency.Based on the dynamic meshing force of each gear as the optimization objective of the transplanting mechanism,the optimization mathematical model of the transplanting mechanism is established,through MATLAB software programming,the optimization results of numerical simulation calculation and analysis are obtained.Conclusion: The meshing result of each gear is mainly reflect in the magnitude of the dynamic meshing force and meshing stiffness and the change of amplitude.In the case of variable speed motion of the transplanting mechanism,the inertial force and centrifugal force generated by planetary carrier are the largest.Therefore,it increases the friction between planetary carrier and components which produced relative moving with planetary carrier and the service life of planetary carrier is reduced.At the same time,under the load,the load of center gear shaft support bearing is the largest.Thus,the load can cause fatigue and damage to center gear shaft support bearing.The inherentfrequency of each order of the transplanting mechanism is higher than the output frequency and will not produce resonance.After optimization,the fluctuation range of the dynamic meshing force of each gear becomes smaller.thus,the risk of fatigue damage of gear teeth is cut down and the service life of the transplanting mechanism is prolonged.