Random Vibration Analysis Of RV Reducer And Fatigue Life Analysis Of Key Components

As a core component in industrial robots,RV reducers are very important for their technical protection abroad,and the research on RV reducers in China is still very much behind the developed countries.This paper takes RV reducer as the research object,and mainly adopts the joint simulation method of ANSYS Workbench and Adams to study the influence of vibration caused by the acceleration of spur gear on the safety and reliability of the input mechanism during the operation of RV reducer using the random vibration analysis based on modal analysis and dynamics simulation,which provides a new idea for calculating the safety margin of RV reducer.The fatigue life of the input mechanism and the cycloid mechanism of the RV reducer was studied,and it was verified that the fatigue life of this RV reducer met the specified requirements.The main studies are as follows.The prerequisite for conducting random vibration analysis is to complete the modal analysis to ensure that the maximum frequency value of power spectral density in random vibration analysis can meet the requirements.Combined with Solid Works and ANSYS Workbench software,a three-dimensional model of the RV reducer is established and the finite element modal analysis of the complete reducer is completed to derive the first tenth order modal frequencies of the system and the corresponding vibration patterns.The meshing frequencies between the parts are calculated through the theoretical analysis,and it is verified that the whole machine will not resonate in normal operation.The random vibration analysis also requires obtaining the acceleration signal of the RV reducer spur gear.Using Adams software,the simulation of RV reducer dynamics was completed.The matching of the angular velocity of the center of mass of the spur gear,output disk and cycloid with the theoretical calculated values was investigated to verify the correctness of the dynamics simulation model.The dynamics simulation of the whole RV gearbox also obtained the variation of the collision load of the input mechanism and the cycloid pinion mechanism,which provided the dynamics parameters for the fatigue life calculation of the input mechanism and the cycloid pinion mechanism.A random vibration analysis example calculation of the input mechanism of the RV reducer was completed using a combination of spectral analysis techniques and finite elements.The acceleration signal of the spur gear is analyzed by autocorrelation and the interference signal is found to exist in the signal.The stress distribution on the meshing surface of the two spur gears and the input shaft gear was studied by using the Random Vibration module in ANSYS Workbench,and it was found that random vibration would cause uneven stress between the two spur gears and the input shaft of the RV reducer.The total maximum stress value of 103.91 MPa was obtained by adding the obtained maximum positive stress value caused by random vibration with the bending stress of the gear teeth obtained through calculation,so that the safety margin of the input mechanism of the RV reducer was calculated as Ms=0.515>0.It was judged that the RV reducer was highly reliable during operation and no abnormal conditions would occur.ANSYS Workbench was used to analyze the fatigue life of the RV reducer input mechanism and the cycloid pinion mechanism.The results showed that the maximum value of contact stress was 103.57 MPa for the input mechanism and233.14 MPa for the cycloid pinion mechanism,both of which occurred at the position where the gear teeth were engaged.The fatigue tool combined with the S-N curve of the material and the load extracted from the Adams simulation to solve the fatigue life distribution cloud of the input mechanism and the cycloid pinion mechanism,and the solution results show that the life of the RV reducer is greater than the standard of 6000 h of trouble-free operation,so the life design of the reducer is qualified.In this paper,by extracting the acceleration signal generated during the operation of the RV reducer,so as to analyze the influence of vibration on the RV reducer,the safety margin during the operation of the RV reducer is studied,which provides a new method for calculating the reliability of the RV reducer during its operation and has certain practical value,and through the study of the life cloud diagram of the RV reducer,the life design of this RV reducer is also verified meets the requirements.