Abstract:With the higher requirement of the low vibration and noise of the spiral bevel gear, it is urgent to design a kind of large contact ratio and smooth transmission of spiral bevel gear. For nonzeronegative modification spiral bevel gear, the machining parameters can be designed with local synthesis to improve contact ratio. By geometric design and machining parameters design, the actual contact ratio of spiral bevel gears can be improved. Using an example, the new design was used to compare with conventional design. With the same load, compared with the conventional design, the maximal tooth root bending stress was reduced 40.5% for the small wheel, 27.5% for the large wheel, and 3.2% for the maximum tooth contact stress of the gear pair. The results show that the new design method makes tooth root bending strength improve greatly, and the gear pair has higher lifetime and reliability.