Steel-steel QN worm gear and its implementation in gearboxes

A high-strength steel-steel worm-type gear is offered with the excluded unfavorable contact zone and repeated contact of the worm with the gearwheel teeth; the high overlap ratio and reduced sensitivity to the action of errors are provided. To ensure the possibility of using hardened steel as a gearwheel material and to maximize the torque as compared to the patented solution of Egorov I. M. and Iofik B. Sh., a curvilinear asymmetric worm profile and contact localization are introduced. Quantitative and qualitative comparison with the closest analogues – worm and spiroid gears – showed the perspective application of such a gear layout, at least in case of low rotational speeds. Equations for calculation of the worm axial module and the dependence of tooth undercutting and sharpening (which are, in fact, limitations at the optimized design) on the main influencing factors are derived. Possibilities of using standard involute hobs and multi-cutter running heads for gearwheel cutting to localize the contact and reduce the cost of gear production are shown. The designed low-speed gearboxes based on the QN worm gear showed their layout advantages and higher performance parameters than common gearboxes. Gearbox testing results are given. The novelty of the work consists in the technical solution itself, its theoretical foundation and experimental confirmation of theoretical prerequisites for obtaining the positive effect as compared to the known analogues.