Study of Contact Strength, Tooth Wear and Metal-Polymer Life of Worm Gears

This paper presents results of a study investigating worm gears consisting of polymer worm wheels and steel involute and Archimedes worms. The author uses his own calculation method to predict polymer wheel wear, gear life and maximum contact pressure in mesh. The effect of tooth correction and wear on gear life and contact pressure is considered. Cases of double and triple tooth engagement are analysed. The worm wheel is made of non-reinforced polyamide PA6. Quantitative and qualitative relationships are established between the maximum initial contact pressure along tooth profile and the tooth correction coefficient. Tooth wear causes a considerable decrease in contact pressure, with the highest decrease observed at the exit of engagement. The maximum contact pressure is generated at the exit of engagement. The same trend is observed for tooth wear. The minimum gear life is observed at the exit of engagement. It increases linearly with increasing the coefficient of tooth correction. The gear life significantly increases (by approx. 56%) in triple tooth engagement compared to double tooth engagement.