Design And Dynamic Analysis Of RV Reducer

As a core part of industrial robots and high-precision mechanical products,RV reducers have received increasing attention in recent years.Although the harmonic reducer in a certain extent can meet the requirement of accurate transmission,because of the presence of the flexible wheel,its accuracy will be significantly reduced with the increase of service time.In order to ensure the precision of precision machinery,the core transmission part must have a long fatigue strength and must maintain high transmission accuracy,while the RV reducer not only has high precision,but also has high fatigue strength.RV reducers are especially important in future developments.Therefore,RV reducer is taken as the research object of this paper,and its structure design and dynamic performance analysis are carried out.At present,the research on the transmission performance of RV reducer is gradually deepened,mainly the research on the theory of cycloidal wheel shaping and the dynamic performance of the whole machine.This article mainly carries on two aspects research.In the aspect of cycloid wheel modification theory,a relatively complete set of theories has been gradually formed.The combination modification research of "positive equidistant+negative shift+tooth height modification" has been carried out to determine the optimal modification amount and verify it.In terms of dynamic performance,based on modification theory and gear dynamics and bond graph theory,the traditional dynamic model of RV reducer transmission and bond graph model of RV reducer transmission system are established respectively,and simulation analysis is carried out respectively.At the same time,in order to further understand the inherent characteristics of RV reducer,modal analysis is carried out on the whole machine and its key parts,so as to avoid reducing the dynamic performance of the whole machine due to structural resonance caused by structural factors.The main research work is as follows1)The structure and transmission principle of the RV reducer are analyzed.According to the existing method of shaping the profile of the cycloidal gear,combined with the principle of conjugate,the repair based on "positive equidistance + negative shift + tooth height modification" is proposed.Shape method.The MATLAB optimization toolbox is used to calculate the shape of the cycloidal profile under the combined shape modification method.2)Based on the three-dimensional parametric modeling software UG,the combined shape of the cycloidal profile curve is obtained and the threedimensional model of the RV reducer is established.The virtual prototype model of the RV reducer is established by ADAMS simulation software to simulate the dynamics.Compare the output speed and analyze the number of meshing teeth and the meshing force to verify that the simulation model is correct.The comprehensive analysis shows the RV reducer after combination modification,and the transmission precision is high.3)Based on the theory of gear dynamics,the mass parameters of modified cycloid wheel are introduced,and the dynamic model of the RV reducer transmission system is established.Because of the slight difference between the meshing stiffness,the meshing damping,the transmission error and the actual motion,there is a slight error in the solution result.By changing the meshing stiffness,the influence on the dynamic characteristics of the RV transmission system is obtained.As the meshing stiffness increases,the meshing force in the transmission process is more stable within a certain range.4)Based on the bond graph theory,the mass parameters of modified cycloid wheel are introduced,and the RV reducer bond diagram model is established.The model considers the effects of friction,meshing stiffness,meshing damping and integrated transmission error.It writes the system equations,solves the system equations,and obtains the system output torque.The kinematic relationship and gear ratio verify that the simulation results are correct and analyze the effects of individual factors on the dynamic characteristics of the RV transmission system.5)Based on the theory of modal analysis,the modal analysis of the whole machine and the key transmission parts of the modified RV reducer is carried out,and the natural frequencies and vibration modes of the whole machine and the transmission parts are obtained.Through the analysis,it is found that the meshing frequency of all levels of gear transmission differs greatly from the natural frequency of all transmission components and the natural frequency of the whole machine,and it is suggested that the resonance frequency should be transited as soon as possible during startup to avoid the influence of resonance on the transmission.