From Gear Metrology to End-of-Line Order Topology: EOL-Blind Geometry Anchoring and Falsification-Based Validation in an Electric-Vehicle Reducer

Manufacturing-induced gear deviations can generate ghost orders, but direct validation from measured geometry to assembled-drive end-of-line (EOL) vibration remains scarce. This study tests an EOL-blind, falsification-oriented workflow for an electric-vehicle reducer. Repeated coordinate-measuring-machine reports of one 24-tooth gear yielded tooth-indexed pitch deviations with a dominant tenth circumferential spatial harmonic (k = 10) on both flanks (spectral-energy cosine similarity 0.952–0.994). Before EOL amplitudes were inspected, k = 10 was frozen and mapped to a sideband-order offset of ΔO = 3.29125; adjacent k = 9 and 11 harmonics and ±0.25-order shifted families served as controls. Industrial testing included 8974 spectra from 8232 unique units. Across mesh harmonics p = 1–6, median symmetric prominence was 0.485, 0.750, and 1.341 dB for k = 9, 10, and 11, respectively. The p = 1–15 analysis suggested a k = 10 advantage over shifted controls, but the eight-bin shift coincided with the local-background boundary and cannot establish specificity. The k = 11 family remained stronger. Grouped holdout against a 31.625-order upper-tail endpoint yielded ROC AUC = 0.488. Independently measured geometry can define an a priori order family, but repeatable spatial harmonics are not necessarily unique or predictive assembled-drive noise, vibration, and harshness (NVH) markers.