The prediction of whine in automotive parallel axis gears

Eliminating the problem of gear whine has proven to be a challenge to engineers for many years. In the current automotive industry, tighter legislation and increased customer awareness mean that whine is more of a concern than ever before. Gear whine originates from steady-state vibrations at the gear mesh. These vibrations are transmitted via a complex transfer path to the passenger compa11ment, where they can be heard as an audible tonal noise. The prominent frequencies of the whine are often close to the most sensitive region of the human car, causing annoyance and influencing passenger perception of quality. An accurate and reliable tool for predicting TE and the onset of whine will alleviate the need for costly and time consuming Noise, Vibration and Harshness (NVH) tests. Past research has attributed the phenomenon of transmission error (TE) to the cause of unwanted vibrations at the gear mesh. A large number of techniques have been developed for measuring and predicting TE, and many techniques for reducing the phenomenon have been proposed. Two novel modelling techniques have been developed as pan of this research in order to enhance understanding of TE and its effect on gear noise. The first approach consists of a quasi-static model developed in MATLAI3. This model predicts the deflection of gear teeth under load and the effect this has on TE. Hertzian contact def1ections are also included in the model. The second modelling approach uses specialised multi-body simulation software to model the dynamic behaviour of the gear pair in question, coupled with the dynamic behaviour of the supporting shafts and the final drive gear pair. Results from both models have been validated against equivalent experimental data. The research project was conducted in conjunction with Ricardo UK Ltd. who are based in Leamington Spa. Ricardo UK Ltd. are a global engineering Consultancy company, specialising in the design manufacture and development of engines and transmissions. Their wide customer base spans automotive, military and off-highway industries. This project succeeds another project undertaken at 1he University of Leeds, which focused on the measurement of automotive based TE subject to realistic operating conditions.