Load-based iterative modification design method for face gear pairs

Edge contact, a common and highly detrimental issue in gear transmissions, significantly degrades gear performance and service life. Point-contact face gear (FG) pairs are particularly susceptible to this issue,as the mating spur gears have 1–3 fewer teeth than the generating gears. To address this problem, a novel load-based iterative modification design method is presented for FG pairs. First, modified FGs are designed using a modified generating gear to determine initial modification parameters, and the potential contact lines of the FG pairs are subsequently determined. Subsequently, loaded contact parameters, including contact patterns, load distribution ratios, and time-varying meshing stiffness (TVMS), are determined according to the load to assess the meshing state. Based on this analysis, the modification parameters are iteratively adjusted in a closed-loop design cycle. Ultimately, the derived modification parameters eliminate edge contact while maintaining stable contact patterns even under 120% of the rated load or installation errors, achieving the optimized tooth surface modification effect. Validation against finite element analysis (FEA) confirms that the proposed method substantially improves optimization efficiency while maintaining accuracy. Results highlight the necessity of load-based optimization.