In modern automotive vehicles, gear noise becomes more and more of an issue. The main reason is the reduced masking noise of the engine, which vanishes completely in the case of an electric driveline. Improved gear quality unfortunately does not correlate with a better noise performance in any case. High gear quality makes sure that the gear flanks are inside tight tolerances and that all teeth are nearly identical. Even if the running behavior of such gear sets shows a very low sound pressure level, the noise perception for human ears may be annoying.
Gears are characterized by a rather complex geometry and tight tolerances, especially compared to other mechanical components. Looking into noise performance of gears, form tolerances are in the single micrometer range to ensure a quiet running behavior. Combined with the geometrical complexity, this is a major challenge for any new metrology standard to be established. For all features and their tolerances, the measuring system must be statistically capable to
ensure appropriate accuracy and repeatability. With today’s tactile measuring system, there are measuring devices available that meet nearly all the requirements. Tactile metrology is characterized by a high accuracy and repeatability as well as a high flexibility. However, for some applications measuring times are rather high, particularly if compared to production cycling times.