Tire Non-Uniformities And Steering Wheel Vibrations

Abstract

Abstract Steering wheel vibrations are frequently related to non-uniformities of the tire/wheel system. While steering system design is a major factor in the sensitivity of the vehicle, the excitation of steering wheel vibrations is due in general to non-uniformities of the tire/wheel system. However, tire non-uniformities are to some extent unavoidable and result in rolling force variation at the spindle during steady state rolling. Therefore, limiting and managing these non-uniformities is of great economic importance to tire manufacturers. The present work demonstrates the tire's role in generating non-uniformity induced dynamic force variations due to 1st order geometric imperfections. Both analytical and numerical approaches are studied. Numerical experiments of the effects of non-uniformities are investigated with the physics based tire model FTIRE. The effects of tire resonance on the non-uniformity force amplitudes are demonstrated through modeling and simulation. The model is then verified using experimental data and the distribution of geometric non-uniformities is studied in a large tire sample based on force measurement data and the model fit. A MSC.ADAMS model of a light truck is combined with non-uniform FTIRE models to study the effect of geometric non-uniformities on steering wheel vibrations. The simulations show that the angular acceleration of the steering wheel around its steer-axis is primarily dependent on force variations in the longitudinal direction (T1H). The effects of phasing, increase in inertia and tire position on the steering wheel vibrations are also discussed.