Pitch cone design and avoidance of contact envelope and tooth undercutting for conical worm gear drives

This paper presents a systematic approach for the design, generation and analysis of conical worm gear drives. The approach is based on the mathematical formulations on the mesh, tooth generation process and conditions for the appearance of contact envelope and tooth undercutting of this type of worm drives. The formulation is implemented by a computer model developed in MatLab environment. By model simulation on worm gear mesh or generation, the conditions for the formation of contact envelope and tooth undercutting are accurately determined for the proper design of worm gear blank and tooth geometry. The computer model can also be used to calculate worm gear tooth geometry and create solid models for the worm gear drives. Numerical examples on conical worm gear drive design, analysis on the problems of contact envelope, limit line and limit point are included in the paper.