The German motion engineering specialist Wittenstein (formerly alpha gearheads) claims to have re-invented the servo worm gearhead with a new design that boosts torque levels by up to 50% and overcomes the problem of backlash increasing during the service life of the gearhead.

The V-Drive gearheads (above) have special concave-profile teeth which are optimised to limit the increase in circumferential backlash that usually occurs during the life of a gearhead. The concave teeth also provide high positional accuracy and overload protection, resulting in the increased torque capability.

There are two versions: one (called the V-Drive⁺) limits the backlash to 3 arc-min; the other (V-Drive economy) limits backlash to 8 arc-min. Both versions promise high power densities and efficiencies of up to 97%. 

The gearheads are aimed, in particular, at servo applications where space is limited or noise levels need to be minimised (the gearheads produce less than 62dBA at 3,000 rpm). They offer synchronous running accuracies of better than 1 arc-min, and can be used in rack-and-pinion applications (shown below). Washdown versions are available and there is a choice of outputs including hollow or solid shafts, as well as flanges.

The V-Drive⁺ version comes on four sizes (with centre distances of 50–100mm) and six reduction ratios from 4–40. The economy version offers a choice of two sizes (with centre distances of 50 and 63mm) and five reduction ratios from 7–40.