Measuring the kinematic accuracy of worm gears

Abstract

A special-purpose machine has been designed and installed to measure the kinematic accuracy of precision worm gears. The primary measurement is the transmission error (TE) between the worm and wheel, and several measuring methods were considered. The chosen method uses optical gratings and a digital system to process the signals, which has particular advantages for this application. This method then makes it a straightforward step also to measure pitch errors of both the worm and the wheel, and lead errors of the worm. A novel method of measuring backlash very accurately is also described.