A method to quantify waviness measurement capability of a gear measurement machine

Abstract

Waviness is an important surface parameter in gears and the capability of measurement machines to capture this is largely unknown. The wavelengths of interest relate to transmission error (TE) and contact stress, both of which depend on a pair of gears and their geometry. TE directly relates to the noise and vibration during operation and contact stress drives failure of gear teeth. Accurately capturing the waviness wavelengths related to these parameters is consistent to geometric product specification (GPS) which requires: (i) specification of functional parameters (ii) description of how to measure each parameter and (iii) evaluation of parameter measurement uncertainty. A GPS compliant method is outlined with verification by two workpiece-like artefacts; one gear finished by surface grinding and one finished by a superfinishing process. The method evaluates a gear measurement machine (Klingelnberg P65) against a reference surface measurement instrument (Talysurf Intra 50). Results show that waviness measurement depends on measurement speed, probe choice, and strategy relating to different gear manufacturing methods. Actions to improve the characterisation method, such as including other key performance indicators and quantification of uncertainties, are suggested.