Abstract:An approach of ease-off topological modification tooth design and correction for hypoid gears was proposed to improve comprehensive meshing performances of the automobile drive axle. The ease-off modification was expressed by both predesigned transmission error function and tooth profile modification curves, and an analytical expression of tooth with free ease-off flank modification for the pinion was established. The ease-off modification parameters were determined by minimizing the amplitude of loaded transmission error(ALTE) based on loaded tooth contact analysis(LTCA), and the objective deviations of theoretical tooth from the ease-off tooth for pinion were developed. Based on error sensitivities of the polynomial coefficients of kinematic axis and cutter head of CNC face-milling machine, flank topographic correction were determined, and reasonable parameter boundaries were determined. The influences of disturbed coefficients on the flank errors were investigated. With minimum sum of squared errors from the objective deviations as the aim function, an optimization algorithm was introduced to solve equations of the corrections. Numerical examples show that the tooth thickness errors and diagonal distortion errors were mainly corrected by the kinematic axes. Besides, with added tool edge correction, a high precision correction of ease-off topological tooth was realized. The study provides theoretical basis for the design, analysis and manufacture of free modified tooth of high-performance hypoid gears.