This study investigates the structural optimization and load-bearing reliability of small gear transmission mechanical equipment under complex working conditions. With the rapid advancement of precision manufacturing and miniaturized mechanical systems

small-scale gear drives are widely utilized in automation

robotics

and micro-mechanical applications. However

their compact structure and high torque density present challenges in ensuring mechanical stability

transmission accuracy

and service life. This paper combines finite element analysis

multi-objective optimization

and reliability evaluation methods to explore the influence of geometric parameters

material properties

and loading modes on the overall mechanical performance. The optimized model achieves an average reduction of 18.6% in stress concentration and an improvement of 23.4% in fatigue life compared with the original structure. The findings provide a theoretical and methodological foundation for the lightweight design and performance enhancement of small-scale gear transmission systems.