Gear tolerancing for simultaneous optimization of transmission error and contact pressure

Abstract

With electrification of vehicles comes an increasing demand on low noise, which for gears translates to transmission error. In this paper, static transmission error, STE, is found for a large number of manufacturing error combinations belonging to different tolerance classes, with focus on those typically used in the automotive industry. There is a lack of studies found in the scientific literature which investigate the link between STE, contact pressure, and manufacturing error tolerances. Therefore, the aim of the present study is to investigate this link. This is done by utilizing a novel simulation tool, developed by the authors, to compute STE for gear sets with pitch and profile slope errors combinations. The model uses a parametric description of the reference profile, includes tooth modifications, uses a hybrid method for compliance, and finds contact from equilibrium. The model handles contact outside the nominal line of action, including tip contact.A simplified method, with predictions based on simulated values, is shown to be accurate and suitable for estimations. Finally, STE is linked to contact pressure for better understanding of how STE and contact pressure interact as a consequence of manufacturing errors. It is shown how this can be used to optimize the gear set with respect to both STE and contact pressure simultaneously.

Keywords

• Transmission error
• Gear tolerance
• Manufacturing error
• Contact pressure
• NVH
• LTCA