This paper addresses the unclear bearing force of an RV reducer shaft by establishing a transmission model and analyzing the force situation of each component. Three force models for the crank support bearing, swivel arm bearing, and main bearing are developed. The force variations under different working conditions and the impact of structural parameters on shaft bearing forces are analyzed. Structural optimization is performed using Kriging-NSGA-II to minimize bearing forces. The results show similar load patterns for the bearings, with the force magnitude being ranked in the following order: rotating arm > crank support > main bearing. After optimization, the bearing forces are reduced by 8.26% for the crank support shaft, 10.35% for the rotating arm shaft, and 5.15% for the main shaft.