Study on the spur involute gear meshing with planar enveloping hourglass worm based on local conjugate

In this paper, a novel multitooth point contact hourglass worm drive is proposed, which is composed of a planar enveloping hourglass worm and a spur involute gear, and both of them can be hardened and precisely ground. This novel hourglass worm drive is also named as involute gear meshing with planar enveloping hourglass worm drive (IP hourglass worm drive). Based on the gear geometry theory and the medium gear, the mathematical models of IP hourglass worm drive are deduced, the theory of tooth contact analysis is studied, as well as the tooth contact analysis is developed by the numerical analysis and finite element analysis. The performance of IP hourglass worm drive has been confirmed by the numerical simulation. This work is expected to give a theoretical basis for the IP hourglass worm drive.