Transfer of NVH limits for highly-integrated electrical drives between end-of-line test benches

The production line of electrical drives finishes with an end-of-line test bench to validate quality standards of newly produced parts. Acoustical quantities resulting from gear noise or eccentricities are measured on the test bench. In order to ensure consistent quality standards across parallel working test benches, one has to identify a method to transfer validated limits from a master to a target EOL. Two methods are proposed and two sets of engine ensembles are used to fathom merits and demerits. We employ measurements of 600 identical electrical drives on both test benches to generate a statistical transfer function for gear noise. An alternative derivation of a transfer function, which can be generated without testing the same electrical drives on both test benches, is proposed. The second approach increases the production capacities during ramp-ups as the required input is provided by normal operation in a series production. The second method is validated by 1200 measurements per test bench and compared to the first method. Method one proves to be only useful for a preliminary transfer of limits, while the second method is valid for long-term production goals resulting in low false-reject rates and no artificial blind spots, consequently guaranteeing high quality standards.