Different formula characteristics of internal gear pair with few teeth difference of novel type double ring reducer are compared

the restricted conditions of them when meshing are set forth.On this basis

the relationships between modification coefficients

tooth addendum coefficient and the center distance are studied

the optimal choice method for modification coefficient based on matlab for the smallest meshing angle is proposed

and it is verified with living example

at the same time the effect of the different step lengths on calculation results is researched.The results show that

the optimum method is accurate

the disadvantages of the other optimal choice methods can be avoided.