Tretyak T. Designing of a tool for machining of non-involute gears with preassigned coefficients of contact pressure and overlap

The dissertation is devoted to the designing of gear cutting tools that provide the specified parameters of pressure and overlap of non-involute gear. To solve the problems of the dissertation the unified mathematical base – the apparatus of multiparameter mappings of space is used. The geometric model of the kinematic curve as a potential profile of the tooth flank of a gear cutting tool, the mathematical model for calculating the tooth profile of gear cutting tool for machining of non-involute gear wheels and the profile of the envelope surface of the tooth of a gear wheel processed by the running method have been developed. The methods of geometrical analysis of the process of shaping the surfaces by spinning gear cutting tools, obtaining profiles of mating surfaces of teeth of non-involute gear wheels as envelope of given surfaces of teeth of tools are described. The mathematical model for calculating the coefficients of the pressure between the teeth and the overlap of the gear is developed. It is shown that non-involute gearings can have larger reduced radii of curvature (and consequently lower pressure coefficients) at the profiles contact points in comparison with involute gearing with increase or decrease in the overlap coefficient of the gearing. The methods of profiling of the cutting part of spinning gear cutting tools for machining of non-involute gear wheels have been developed. New varieties of precast gear-shaping cutters with prismatic and round formers, which ensure the invariance of the profile of the cutting edges after regrinding, are proposed. The developed methods, as well as the designed cutting tools have been tested and implemented in design organizations and at enterprises of Kharkiv.