Gear Metrology

Gear drives represent key components for all kind of vehicles, machine tools, aircrafts, household appliances as well as a broad variety of industrial equipment and toys. The designers are confronted with increasing demands concerning lifetime, power transmission and noise emission, whereas the size and weight of gear drives is constantly reduced. Thus, the measurement of gears and gear tools is of decisive importance for gear production. This paper reviews the state-of-the-art of gear metrology, where tactile probing methods dominate almost exclusively. It summarizes new modelling and measuring principles, enabling a superficial description and inspection of gears. Especially optical measuring methods, the inspection of micro gears and alignment problems are discussed in detail. A final section reports the actual accuracy limits of gear measurements. It points out that a significant reduction of the measuring uncertainty associated with gears, standards and instruments is an urgent need for the production of high-precision gears.