Optimal machine tool settings for face-hobbed hypoid gears manufactured on CNC hypoid generator

Abstract

In this study, a method is proposed for the determination of optimal machine tool setting for the manufacture of face-hobbed hypoid gears on CNC hypoid generators. The optimal head-cutter geometry and machine tool settings are determined to introduce the optimal tooth modifications into the teeth of face-hobbed hypoid gears. The goals of the tooth surface modifications are to reduce the tooth contact pressure and the transmission errors and to decrease the sensitivity of the gear pair to errors in tooth surfaces and to the relative positions of the mating members. An optimization methodology is applied to systematically define the optimal head-cutter geometry and machine tool settings to simultaneously minimize tooth contact pressures and angular displacement error of the driven gear. The method is based on the machine tool setting variation on the cradle-type generator conducted by polynomial functions of fifth order. An algorithm is developed for the execution of motions on the CNC hypoid generator using the optimal relations on the cradle-type machine. Effectiveness of the method was demonstrated by using a face-hobbed hypoid gear example. Significant reductions in the maximum tooth contact pressure and in the transmission errors were obtained.