Multi-objective optimization design of modified face gear pairs for torque-split transmission configurations

Purpose The actual operation of face gear pairs in torque-split transmissions is prone to edge contact and nonuniform tooth surface loading. These issues, stemming from machining errors, installation inaccuracies and structural deformation under load, result in inconsistent contact patterns. Consequently, tooth surface modification is an essential measure for improving the service performance of face gears. Design/methodology/approach Based on the theory of face gear pair modification, a differential corrective design is proposed for the gear pairs in a torque-split transmission system. The design optimization targets the dual objectives of expanding tooth surface contact area and reducing transmission error fluctuations. Subsequently, a comprehensive optimization framework is developed based on numerical tooth contact analysis and loaded tooth contact analysis models to achieve the differential modification across the transmission branches. Findings The optimal modification parameters are derived through computation with the Non-dominated Sorting Genetic Algorithm-II genetic algorithm. A finite element simulation model of the optimized system is subsequently constructed to assess the enhancements in gear meshing performance. Experimental validation demonstrates that the optimized parameters effectively improve the contact path, contact pattern, tooth surface stress distribution and transmission error characteristics. Originality/value This paper presents a modification scheme for face gear torque-split transmission systems, validated to meet practical requirements. The findings serve as a theoretical foundation for future surface modification of aviation face gear pairs.