Load State of Low-Speed Spiroid Gears

Abstract

The problem of analyzing a heavy-loaded low-speed multi-pair spiroid gear with account of the influence of elastic and elastoplastic contact, bending and shearing interaction of spiroid gearwheel teeth and spiroid worm threads is considered. The main steps of the developed algorithm for calculating the load distribution and plastic strain of flanks taking into account the elastic and elastoplastic nature of the contact, multi-pair character of meshing, and macro- and micro-roughness of flanks of gear elements are briefly described. For the case of elastoplastic contact, zones of plastic contact on spiroid gear tooth flanks are determined, and the value of plastic strain is calculated. Flanks of spiroid gear teeth are presented in the algorithm as a set of areas (cells) with coordinates of centers calculated taking into account the analyzed factors influencing the load distribution in the spiroid gearing, such as manufacturing and (or) assembly errors, macro- and micro-roughness, and deformation of spiroid gear supports. The manuscript presents numerical results of studying real spiroid gears for gearboxes of pipeline valves (PV) having the elastic and elastoplastic character of contact, presented in the form of summary tables and diagrams of torque distribution, load concentration factors in contact areas and plastic strain areas, demonstrating the efficiency of the algorithm. Results of comparing the gearboxes of different generations are given that show the ways of applying this algorithm at the design stage and results of improving load characteristics of new generations of gearboxes. Numerical results of the algorithm operation correlate well with the operating experience and can be used to analyze the load-carrying capacity of spiroid gears.