To improve the bearing capacity of orthogonal variable transmission ratio face gear,the influence of basic parameters of gear pair on strength characteristics was discussed.According to spatial gear meshing theories,differential geometry and design of machinery, the meshing coordinate and the equation of tooth surface were established.The methods for calculating the pressure angle and the principal curvature of variable transmission ratio face gear were acquired.The force analysis in the meshing process was performed.A method to calculate the strength of orthogonal variable transmission ratio face gear pair was established,and then the variation regulation of contact and bending stresses that changed with the basic parameters of the gear pair was derived.The comparison with the result of the transmission test and the theoretical data verified the calculation method.
