Research on methods of tooth contact analysis and modification optimization for internal spur gear pair

Internal spur gear pair is widely used in industry. There is little current research on how to analyze and modify internal spur gear pairs that affect design and transmission performance. In this paper, a modeling method and an improved tooth contact analysis (TCA) method for internal spur gear pair are presented. The comparison between the improved TCA method and conventional TCA method is done, and the correctness and advantage of the improved TCA method are proved. The loaded tooth contact analysis (LTCA) method for spur gear pair is studied, and its feasibility is verified by Romax. Based on the method of penalty function, a modification optimization method of internal spur gear pair is proposed. Compared with the conventional particle swarm modification optimization, the proposed modification optimization method of internal spur gear pair is suitable for engineering application from the view of time-consuming and result. In order to facilitate modification, a modification parameter conversion method is proposed, and the conversion formulas from the modification length on tooth root of pinion to that on tooth tip of ring gear is derived. A dynamic model for internal spur gear pair is built, and dynamic simulation is carried out. The analysis results show that the optimization of the correction can significantly reduce the mean square value of the vibration acceleration. The research results supply a basis for the analysis and the modification optimization of internal spur gear pair.