Worm gearing for vehicle window drive - has worm of helically wound wire with abutments preventing axial separation of helical turns

摘要

The worm drive has a helically bent wire constituting both a worm and a flexible shaft. The wire has lateral teeth such that teeth of one of the helix engage between the teeth of the adjacent turns. This provides torsional stiffness while allowing bending. To avoid axial separation of the turns, the teeth may be of dovetail shape with the divergent teeth of one turn engaging dovetail slots formed between the teeth of the adjacent turns. The shaft may be contained in a tube having abutments preventing axial expansion of the shaft.