Research on singularities of base worm thread surface forhobbing or grinding face gear

In order to produce face gear by a hob or grinding worm,a base worm used for hob or grinding worm was designed.In the investigation,a coordinate was established to describe the enveloping process of the worm,the equations describing the worm thread surface were presented,and the three-dimensional(3-D)entity of base worm was created by Catia.The derivation and avoidance of singularities of base worm thread surface was analyzed.A numerical example was given to calculated singularity point.The influence of the base worm radius,the module of shaper,the teeth number and the pressure angle on the singularity point were analyzed,respectively.