Contact characteristics of spherical helical gears

Spherical helical gears with tooth flank modification were proposed to enhance loaded capacity and improve the sensitivity to assemble errors. The mathematical model of tooth surface was developed by the imagine rack-cutter and gearing theory, and the modification with parabolic curve of rack-cutter was applied to produce a required transmission error curve and improve meshing characteristics. Then, the tooth contact analysis model was established on the conditions of continuous tangency of two contact surface, of which the assemble errors were considered. The simulation results show that the capacity of loaded capacity and tooth contact ratio can be increased by the contact pattern of convex-concave type gears along the helical tooth traces, and the error sensitivity of contact pattern of the convex-convex and convex-helical types of spherical gears can be improved by tooth modification.