Numerical and experimental study on surface topography of spur gear generated by double-roller gear ultrasonic rolling

Abstract Compared with shot peening, the Double-roller Gear Ultrasonic Rolling (DGUR) process not only improves gear fatigue properties but also effectively reduces surface roughness. However, there is a lack of surface topography modeling methods for this process. Based on the Hertzian contact theory, this paper introduces a numerical model for the DGUR process that incorporates initial residual stress and the surface topography of the sample gear. Subsequently, DGUR experiments were conducted with four different processing parameters. The experimental and simulated results are consistent for both gear surface topography and two-dimensional gear face profiles, and the relative errors of 3D roughness parameters Sa and Sq were less than 5%, confirming the model’s validity. Based on this model, we investigated the relationship between the DGUR process and the Sa , Sq parameters. The experimental outcomes indicated that the DGUR treatment considerably improved the gear tooth surface roughness, decreasing Sa from an initial 0.497 μm to 0.144 μm and Sq from 0.595 μm to 0.203 μm, thereby significantly improving gear tooth surface roughness.