Tribological properties of flexspline materials regulated by micro-metallographic structure

Flexspline wear is a critical factor leading to harmonic drive failure. This study investigates the tribological properties of five typical flexspline materials under dry friction conditions. A wear mechanism regulated by micro-metallographic structure is proposed. Tempered sorbate was confirmed to be the desired metallographic structure from a tribological perspective. Additionally, a suitable cementite content could promote the anti-wear characteristics of friction interfaces. However, the metallographic structure of granular ferrite was found to be unfavorable. Tribological experiments under start-stop conditions were conducted to analyze the impact effect during harmonic drive operation. The grain level and speed-dependent properties of the flexspline materials were determined. This research provides important information for avoiding flexspline wear and consequent failure of harmonic drives.