High-performance precision gear drives such as harmonic gear have high requirements on tooth profile accuracy, surface quality, fatigue life and other service performance characteristics, which urgently needs an effective surface strengthening method. This work aims to examine the feasibility and effectiveness of fine particle peening (FPP) treatment on surface integrity of flexspline in harmonic drive precision transmission. To this end, FPP process experiments were carried out, and this process was simulated based on a coupling method of discrete element method and finite element method (DEM-FEM) considering the kinematic hardening behavior of the material. The simulation results were in good agreement with the test results. Effects of shot peening pressure, injection velocity, material properties and tooth profile on surface roughness and induced residual stress of the target flexspline were analyzed. The results reveal that after FPP, the amplitude of residual compressive stress of the flexspline can reach 470 MPa, and the surface roughness Sa becomes approximately 0.5 μm. For precision gears with low hardness such as flexspline in harmonic drive, it is suggested to adopt FPP with low air pressure to achieve both saturated residual compressive stress and lower surface roughness, thus benefitting enhanced fatigue life.

谐波齿轮等高性能精密齿轮传动对齿形精度、表面质量、疲劳寿命等使用性能特性要求很高，迫切需要一种有效的表面强化方法。本工作旨在研究细颗粒喷丸（FPP）处理对谐波传动精密传动中柔轮表面完整性的可行性和有效性。为此，进行了FPP工艺实验，并基于离散元法和有限元法(DEM-FEM)的耦合方法，考虑材料的运动硬化行为，对该工艺进行了模拟。仿真结果与试验结果吻合较好。喷丸压力、注射速度的影响，分析了材料特性和齿形对目标柔轮表面粗糙度和诱导残余应力的影响。结果表明，FPP后柔轮残余压应力幅值可达470 MPa，表面粗糙度Sa变为约0.5μm。对于谐波传动中的柔轮等硬度较低的精密齿轮，建议采用低气压的FPP，既能达到饱和残余压应力，又能降低表面粗糙度，有利于提高疲劳寿命。