Long-lasting and effi cient – without grinding teeth!

Large gears have become an indispensable part of modern mechanical engineering. Besides wind power, other industrial sectors such as shipbuilding and oil production engineering rely on the use of large gears. Gear effi ciency, noise emission and service life depend decisively on the quality of the gears used. In superior accuracy classes, dimension and form tolerances below 10 μm are, for example, required for a 1 m gear.

Within the scope of an EU research project, PTB has developed a large gear measurement standard and a high-precision measuring device by which large components can be calibrated directly in industry. The special design of the measurement standard as a segment allows the measurement standard to realize a complete toothed gear of 1 m in diameter which can, however, still be calibrated on the established measuring devices at PTB. Different helix angles (0°, 10°, 20°) and hands of helix (straight, left-hand, right-hand) allow the measurement standard to be universally used. All relevant measurands were calibrated on a coordinate measuring machine using a multiple orientation measurement procedure. The results lie within the estimated measurement uncertainties of less than 5 μm.

The large gear measurement standard can be used for round robin comparisons. Currently, an industrial round robin comparison is in preparation; both manufacturers of measuring instruments and manufacturers of gears are to take part in it. Furthermore, the large gear measurement standard provides the basis for future accreditations in the fi eld of large gears via the DAkkS.