Abstract
Road noise is one of the main interior noises in passenger cars. This phenomenon is caused by road roughness, and tire vibration characteristics play a major role. Recent research showed that not only radial vibration but also lateral vibration of a tire has an impact on road noise. This paper describes the modeling of tire lateral vibration and one idea for control of natural frequency against tire lateral vibration. First, experimental modal analysis was performed to reveal the mode shape exciting lateral vibration. Accelerometers were put on three positions of the tread lateral direction, two positions of each sidewall, and 12 positions of the circumferential direction every 30 degrees. Mode shape and natural frequency were confirmed. Second, we built the tire vibration model based on thin cylindrical shell theory. This model has a tread ring as a continuous body and springs expressing the sidewall stiffness. It is assumed that tire vibration follows non-elongation deformation. Kinetic and potential energy were derived, and natural frequencies were predicted by Rayleigh's method. The theoretical value of lateral bending mode closely corresponded to the experimental data. Focusing on unknown parameters regarding tread, sidewall stiffness and tension, only the latter two have influence on natural frequency. Finally, sensitivity analysis was performed using a natural frequency formula. Changing tension, sidewall stiffness, and change ratio of natural frequency were confirmed.
