微粒子喷丸作为高性能齿轮制造的关键技术之一，准确地分析其对齿轮法向接触刚度的影响规律是研究齿轮动力学及齿轮精密制造的重要课题之一。本文通过对微粒子喷丸齿轮表面微观形貌表征，对比分析微粒子喷丸前后齿面微观形貌变化情况，结合分形理论，考虑单个微凸体弹性-弹塑性-塑性变形及微凸体间相互作用关系，建立微粒子喷丸齿轮法向接触刚度分析模型。仿真分析法向接触刚度随法向载荷、分形维数D、分形粗糙幅值G及材料特性参数的变化规律；利用功率谱密度函数法提取微粒子喷丸齿轮表面分形参数，分析微粒子喷丸对齿轮法向接触刚度的影响。结果表明：微粒子喷丸使得齿面形成随机分布的微米级甚至纳米级凹坑，降低齿面表面粗糙度，但齿面表面粗糙度随微粒子喷丸强度的增加而增加；法向接触刚度随法向载荷、材料屈服强度、齿面分形维数D的增大而增大，随齿面分形粗糙幅值G的增大而减小。微粒子喷丸通过改变齿轮表面微观形貌，进而改变分形维数D和分形粗糙幅值G，使得齿轮法向接触刚度发生变化，与未喷丸齿轮相比，微粒子喷丸能够提高齿轮法向接触刚度，且随着微粒子喷丸强度的增加，齿轮法向接触刚度降低。研究结果为齿轮动力学研究及高性能齿轮制造提供理论基础。

Fine particle shot peening is one of the key technologies for high-performance gear manufacturing. In the study of gear dynamics and gear precision manufacturing, one of the important research topics is accurately analyzing the influence of fine particle shot peening on the normal contact stiffness of gear. In this paper, the changes of micro morphology of gear teeth surface before and after the fine particle shot peening were compared and analyzed through characterizing the micro morphology of the fine particle shot peened gear surface. Based on the fractal theory, the normal contact stiffness model of the fine particle shot peened gear was established considering the elastic-elastoplastic-plastic deformation of a single asperity and asperity interaction. It conducted a simulation analysis on the variation law of the normal contact stiffness along with the normal load, the fractal dimension D, the fractal rough amplitude G and the parameter of material property. The influence of fine particle shot peening on the normal contact stiffness of the gear was analyzed by extracting the fractal parameters of fine particle shot peened gear surface with the power spectral density function method. The results show that fine particle shot peening leads to randomly distributed micron or even nanoscale pits on the gear surface, and the decrease of surface roughness. Also, the gear surface roughness increases with the increase of fine particle shot peening strength. The normal contact stiffness increases with the increase of normal load, material yield strength, and fractal dimension D, and decreases with the increase of fractal roughness amplitude G. Fine particle shot peening can change the gear normal contact stiffness by changing the micro morphology of gear surface, and then change the fractal dimension D and fractal roughness amplitude G. Compared with the gear without fine particle shot peening, the normal contact stiffness of fine particle shot peened gears is improved. With the increase of shot peening strength, the normal contact stiffness of gears decreases. The research results provide a theoretical basis for gear dynamics research and high-performance gear manufacturing.