Optimization And Finite Element Analysis Of Double Meshing Tooth Needle Cam Indexing Mechanism

As a brand new type of intermittent mechanism, whose input shaft, pin gear shaft and output shaft are collinear, the double meshing tooth needle cam indexing mechanism has some advantages such as compact structure, high load-capacity, much indexing number and Smooth transmission and so on,so it will be widely used in the future.Based on the existing prototype, theoretical analysis on the meshing efficiency is established, after this take the volume of the internal structure and the average transmission efficiency for multi-objective optimization by using genetic algorithm and the fatigue simulation analysis of the cam and cycloid gear are carried out, at this time, the relevant dynamic analysis is also calculated in this paper.Firstly, using the profile equation of the cam and cycloid gear to calculate and analysis the relative velocity between the above two parts and needles with considering the frictional force in this thesis. The overall transmission efficiency is solved according to the actual transmission of the mechanism. As a result, the instantaneous meshing efficiency during the indexing period is calculated and the factors that influence the average meshing efficiency are analyzed too.Secondly, regard the internal structure volume of the prototype and the average meshing efficiency as the optimization object. According to the geometric characteristics and transmission principle of the mechanism to set Rz1,Rz2,e,Bng,Btg,Bzg as design variables and to establish the objective function and using the genetic algorithm to complete the multi-objective optimization of the mechanism.Then, according to the fatigue parameters of material properties, the fatigue life prediction of the cam and cycloid gear are carried out by using the method of finite element analysis. The modification scheme is presented in order to solve the problem of the cam’s safty factor is small and doesn’t reach the design life.Finally, the equivalent total equivalent torsional rigidity of cycloid gear and cam in the motion process is analyzed and calculated by establishing the equivalent dynamics model and the natural instantaneous frequency range is also presented. At the same time, using the Workbench for modal analysis on the mechanism, giving analysis of the vibration mode under each order modal and predicting the possibility of resonance vibration between the above two parts and the system.