Calculation and Development of 3k Planetary Gearbox with Non-standard Gear Modules

Achievement of high gear ratios in gear modules, applied in servos of constrained-size robotic devices, is a challenging task, which requires dedicated transmission types. This paper presents an analysis of calculation methodologies of compact mechanical gears with high gear ratios, their designs and features. An operating principle of 3K planetary gearboxes is described. A calculation methodology for 3K type planetary gearboxes is presented with high gear ratios, implemented in one stage using non-standard gear modules of input and output links, what allows to reduce gear size, retaining the high gear ratio. A case for 3K gearbox calculation is given using the proposed methodology, as well width selection for toothed rims, via simulation models of strength tests in CAD for one of the calculated gear variants with gear ratio of 160. The proposed methodology can be used planetary gear design with high gear ratios and low stage number with potential applications in healthcare, robotics and other domains, where the mass and size characteristics of mechanical gears are of primary concern.