Research On The Cycloid Gear Tooth Profile Modification And Analysis Of Transmission Performance For RV Reducer

RV reducers is widely employed in the field of industrial robots because of its high reduction ratio,high transmission accuracy and stable transmission performance.As the core part of RV reducers,the cycloid gear modification greatly affects the transmission performance of RV reducers,including its bearing capacity,transmission accuracy,smooth running and other aspects,which are all affected by the cycloid gear modification.At present,there are many studies on the cycloid gear modification,but most of them are based on the single objective modification.Few people consider the bearing capacity and running stability on the basis of ensuring the transmission accuracy.This thesis mainly studies the cycloid gear modification theory,RV reducer transmission performance,cycloid gear tooth profile modification optimization and other aspects.The main research contents are as follows:(1)Conduct theoretical research on RV reducers.Analyze the relationship between rotational speed and torque at all levels through studying the structure of RV reducers.According to the formation principle of the cycloid gear tooth profile,we can deduce the cycloid gear standard tooth profile equation,obtain the cycloid gear curvature radius formula,calculate the change rule of curvature radius,and establish the foundation for the cycloid gear tooth profile modification.Comparative analysis of different cycloidal tooth profile modification method is carried out.According to the different backlash Angle of different methods,we choose the optimal combination modification method.Based on the above work,we derive the cycloid gear modification tooth profile equation,analyze different amount of modification and meshing theory of contact stress relationship,study the RV reducer drive performance,and finally analyze the transmission efficiency,cycloid gear and pin gear meshing condition continuously.(2)The three-dimensional model of RV reducers is established by UG,and the finite element model is established by Workbench.The sun and planetary gears in the first reduction mechanism and the cycloid gears and the pin teeth in the second reduction mechanism are analyzed by transient dynamics,and their contact stress is explored.On the basis of the modal analysis for the RV reducer machines,cycloid gears,and crank shafts,their natural frequency is explored to prevent resonance.(3)Study the tooth profile modification of cycloid gears.Firstly,several finite element models and dynamic models of RV reducers,which are based on modification quantities according to the method of "negative equidistance + positive shift distance",are established as prediction samples.Then,the corresponding maximum contact stress and operation smoothness are obtained through the simulation analysis.Next,the mapping relationship among the maximum contact stress,running stability and modification amount is obtained by utilizing back propagation training.At last,due to the mesh clearance and material strength can be guaranteed by the genetic algorithm,the optimal modification value,which is calculated by minimum weighted fitness of the maximum contact stress and running stability,can be solved.(4)The RV reducer performance test platform is built,and the transmission efficiency and transmission error of the RV reducer prototypes are tested.In order to facilitate the crankshaft eccentricity measurement,the crankshaft eccentricity measurement device of RV reducers is designed.