Dual-lead worm gear

The Renold DL series dual-lead worm gear consists of two leads. One tooth side of the worm thread and the mating side of the tooth are manufactured with one lead, while the other tooth side and the mating side of the tooth are manufactured with a slightly different lead.

In the case of worms, this has the effect of creating worm threads, which increase in thickness from one end of the worm to the other.

Therefore, if the worm moves axially as it engages with the worm gear, the backlash between the worm pairs can be adjusted to the desired amount.

In practice, gears are made such that the initial backlash is achieved at a distance relative to the datum plane on the worm. Then, during the life of the gear, the worm can be adjusted from that point as needed.

The DL series of dual-lead worm gears offers a number of advantages for split worm gear designs. It provides a kinematically correct gear that can operate in either direction of rotation and its backlash can be infinitely adjusted from the maximum acceptable value to zero.

Precision double-lead clearance adjustable worm gears are widely used in rotary tables, tool drives and machine tool positioning mechanisms