Lattice Contact In Generated Spiral Bevel Gears

Abstract

The tooth surfaces of generated spiral bevel gears are composed of a large number of flats, or facets, spaced so closely that substantially smooth surfaces result. In the simplest form of such gears, having constant-depth teeth, these facets on each member coincide in direction as the gears mesh together. For the more common case of teeth with tapering depth, there is a small angle between the flats of the mating members. This paper describes how spiral bevel pairs can be generated on standard machines with standard cutters in such a way that the flats on the mating members cross each other at a substantial angle, so that an averaging effect is produced and only a small fraction of the flat-height is reflected as error in the output motion. This results in reduced noise, permitting higher production rates, less lapping time, and less required accuracy in the cutter truing operation.