Research On Assembly Error Characteristic And Selection Assembly Optimization Method Of Harmonic Reducer

Harmonic reducer is a kind of precision reducer widely used in the fields of robots,aerospace,etc.It has the advantages of high precision,large load,small size,light weight and so on.Assembly error is one of the factors that affect the transmission performance of the harmonic reducer.However,harmonic reducers manufactured by the interchange assembly method that product performance consistency cannot be effectively guaranteed.In view of these problems,this study combined the project of "harmonic reducer for robot" and conducted research on assembly error characteristic,and selection assembly optimization method.The main research contents and results are as follows:(1)Analyze the assembly dimension chain and extract key assembly errors,and explore the influence of assembly errors on the deformation of the flexible wheel;classify and analyze each error source based on the generation mechanism of the transmission error,derive the calculation formula of the transmission error and verify the correctness through experiments;The sensitivity analysis of the transmission error to each error source indicate that the assembly eccentricity error of the flexible wheel and the rigid wheel and the processing error of the gear are the main sources of the transmission error.(2)Establish static model and transient dynamic model of the harmonic reducer,explore the influence of the rigid wheel and its load on the flexspline stress,and calculate the cyclic stress of the flexible gear under rated conditions.Study the effects of various assembly errors and their interactions on the stress of the flexible wheel through orthogonal experiments.The results of range analysis show that the axial assembly errors of the wave generator and the flexible wheel have the greatest influence on the stress of the flexspline stress.(3)Simulate of the impact of axial assembly errors on the fatigue life of the flexible gear through nCode SN TimeStep tool based on Miner’s linear cumulative damage theory.Calculate the safety factor of flexible gear life under different assembly errors through the inversion operation.Build a fatigue life test bench and verify the correctness of fatigue simulation analysis through the test.(4)Establish the mathematical model of selective assembly with the maximum assembly qualification rate as the objective function,the transmission accuracy and fatigue life as constraints.Design the selection algorithm to select parts in groups.Explore the assembly process of harmonic reducer and design the assembly scheme and special fixture.The assembly examples show the feasibility of the selection assembly optimization method of harmonic reducer.