ABSTRACT
This chapter deals with the three principal types of nonspur gearing: helical, worm, and bevel gears. The geometry of these different types of gearing is considerably more complicated than for spur gears. Like spur gears, helical gears are cut from a cylindrical gear blank and have involute teeth. Herringbone gear refers to a helical gear having half its face cut with teeth of one hand and the other half with the teeth of opposite hand. The chapter is concerned with the applied forces or loads acting on the tooth of a helical gear. The equations for the bending and wear strengths of helical gear teeth are similar to those of spur gears. Bevel gears are cut on conical blanks to be used to transmit motion between intersecting shafts. Worm gearing can be employed to transmit motion between nonparallel nonintersecting shafts. Worms can be made with single, double, or more threads. Worm gearing may be either single enveloping or double enveloping.
