Design of high contact ratio spur gears cut with standard tools

摘要

In high precision and heavily loaded spur gears, the effect of gear error is negligible, so the periodic variation of tooth stiffness is the principal cause of noise and vibration. High contact ratio spur gears can be used to exclude or reduce the variation of tooth stiffness. A simple method of designing high contact ratio spur gears cut with standard tools of 20° profile angle is presented in this paper. It consists of increasing the number of teeth on mating gears and simultaneously introducing negative profile shift in order to provide the same center distance. Computer programs to calculate static and dynamic transmission error of gears under load have been developed to evaluate dynamic properties of gears. The analysis of gears using these programs showed that gears with high contact ratio of 1.96 have much less static and dynamic transmission error than standard gears.