| The wave generator is one of key components in the harmonic gear reducer. However, the flexible bearing, as the large deformation elastic component, easily has fatigue failures because of the cycled and alternated load. The load is normally produced by the interaction force which is generated by the cam of the wave generator and the flexspline. When the fatigue failure occurs in flexible bearing, the working life of the harmonic gear reducer will be reduced and then the economic loss is inevitable. Thus, the fatigue life analysis and the structural optimization of the flexible bearing are very important under the condition of satisfying the strength.Based on one harmonic gear reducer, the fatigue life and structural optimization of the flexible bearing are the main researches in this thesis. The acquired innovative achievements are as follows(1) The structural design and the virtual prototype model of the wave generator. Firstly, the profile curve of the rigid cam is designed based on the transmission principle of the harmonic gear and the deforming rule of the flexspline. And then, the structural parameters of the flexible bearing can be obtained through studying the movement trail of the flexible bearing. Finally, the virtual prototype model of the rigid cam and the flexible bearing can be built by using UG.(2) Building the finite element analysis module of the wave generator. The obtained virtual prototype model is imported to FEM softwares, HyperMesh and MARC, respectively. The maximum stress curve can be obtained by using the quasi-static contact analysis under the rating condition.(3) The fatigue life analysis of the flexible bearing in the wave generator. The failure forms of flexible bearing are researched. The software, MSC.Fatigue, is applied to the bending fatigue life simulation analysis of the flexible bearing at the rated operation condition. Also, the contact fatigue life can be obtained by theoretical calculation on the condition that the bending fatigue failure does not exist. Finally, the fatigue life of flexible bearing can be obtained.(4) The structural optimization of the flexible bearing in the wave generator based on the above fatigue life analysis. The optimal structural parameters of the flexible bearing can be obtained firstly by the genetic algorithm, with the goal of maximizing the objective function, namely the fatigue life of the flexible bearing. The relationship of structural parameters is the constraint condition. Finally, the flexible bearing with optimal structural parameters is subject to the quasi-static finite element analysis to check its strength.In this thesis, the finite element analysis, the fatigue life analysis and the genetic algorithm are used to solve the actual engineering problem. A reasonable and practicable way is proposed to accurately check the strength and improve the fatigue life of the flexible bearing. The research result is really helpful to develop and design the flexible bearing with the high working life. |
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