US Patent 7431110 High-torque gear assembly for personal mobility apparatus

A high-torque gear assembly for a personal mobility apparatus is disclosed generally comprising a shaft that drives a drive wheel of the personal mobility apparatus, a worm driven by a motor, and a worm wheel coupled to the shaft and driven by the worm, where both the worm wheel is a globoid gear and the worm is a globoid worm. In some embodiments, a gear train is coupled between a gear shaft and a drive wheel shaft for translating the rotational motion. In certain embodiments, the worm wheel and the worm have a gear ratio of at least 10:1, and the worm has a lead angle between twenty and thirty degrees.