## 5 Conclusions  
This paper puts forward a calculation method of the dynamic meshing force of a single pair of gear teeth by constructing the nonlinear dynamic model of spur gear pair considering the meshing state of multiple pairs of teeth based on the actual meshing characteristics of gear teeth. The new method can be used to effectively calculate the dynamic meshing force and load sharing ratio of each pair of teeth with different meshing characteristics, especially various tooth surface characteristics and deviations. Considering the tooth profile deviation, based on the established dynamic model and the calculation formula of dynamic meshing force, the effects of different parameters on the dynamic response and the dynamic meshing force of the system are analyzed. The results show that these parameters all have effects on the dynamic characteristics and dynamic meshing force, but their effects are different. Therefore, in order to accurately analyze the dynamic response and dynamic meshing force under different meshing conditions, especially the dynamic meshing force of a single pair of teeth, the influence of these parameters needs to be fully considered, which is very important to predict the load capacity and carry out the parameter optimization for gear system. In addition, the method presented in this paper also lays a foundation for analyzing and predicting the dynamic behavior or the load capacity of HCR gears. In this paper, only the influences of tooth profile deviations on the dynamic response and dynamic meshing force of gear system are discussed. Considering that HCR gears are more sensitive to the tooth meshing state, the influence of more tooth surface and deviation parameters, such as tooth profile modification, pitch deviation, installation deviation, etc., on the dynamic response and dynamic meshing force of HCR gears will be studied, which is also the focus of our next work. Conceptualization, R.X. and J.Z. ; methodology, J.W. ; software, R.X., R.L. and Z.W. ; validation, L.X. and Z.W. ; writing--original draft preparation, R.X. ; writing--review and editing, J.Z., J.W. and H.L. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Natural Science Foundation of China (grant number 51775156), the Anhui Provincial Natural Science Foundation (grant number 2108085 ME169), the University Synergy Innovation Program of Anhui Province (grant number GXXT-2019-048), the Anhui university scientific research platform innovation team building projects (2016-2018), the Scientific Research Foundation for Talent Introduced (grant number 2019 YQQ005), the Scientific Research Project (grant number \"Xjky2020008\") of Anhui Polytechnic University, National College Students' Innovation and Entrepreneurship Training Program (grant number 202110363014) and Open Research Fund of Anhui Engineering Technology Research Center of Automotive New Technique (grant number QCKJ202006). **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The data presented in this study are available upon request from the corresponding author. **Conflicts of Interest:** The authors declare no conflict of interest. **Nomenclature**