... and performance evaluation of a modified-hourglass worm drive. A slight modification of type-II worm gearing can effectively avoid undercutting of the worm gear. The reason for this is that a part of one subconjugate zone, including the curvature interference limit line, can be cut out spontaneously. Hence...

..., the meshing function is obtained and leads to the necessary condition of existence of the enveloping surface. The helix and helix lead angle are then proposed for meshing between the sun-worm and planet worm-gears and both undercutting curve and meshing limit curve are introduced. This further leads...