In order to solve the problem that the traditional involute worm helical gear is prone to root fracture when the transmission ratio is too large

a new involute worm pair based on unequal modulus and pressure angle is put forward

which can increase the modulus and pressure angle of the helical gear at the sartime and greatly improve the root strength of the helica gear. By analyzing the transmission characteristics of this kind of worm pair

a special calculating method of meshing angle and center distance is obtained. In addition

through the modeling and finite ele

ment analysis of ZI worm helical gear pair and traditional Zl worm helical gear pair designed based on unequal modulus in the same transmission ratio and worm. it is found that the root strength of helical gear in the case of large modulus ratio is about 2.956 times that of traditional helical gear

which increases the application range of involute worm. The sum of squared errors (SSE) minimum model is compared with grey predictionto verify the accuracy of prediction. The maximum stress

σ

1max

of helical gear meshing teeth under different torques is predicted

which provides a basis for corresponding engineering analysis and necessary checking design.