Study on lug tire model considering change of the grounding point with rolling

Abstract

Lug tires are one of the main sources of vibration in agricultural tractor. These tires have special irregularities called lugs, which generate vibratory force when traveling on paved surfaces. In addition, in recent years, deregulation, such as maximum speed and driving condition on public road with work equipment has been implemented to improve an efficiency of agricultural work. To adapt these deregulations, it is necessary to reduce vibration caused by the lug excitatory force. However, the force characteristics caused by lug characteristics, such as the number and stiffness of lugs, have not been clarified. In this study, the lug shape was modeled as a rigid circular ring with an uneven shape, and load variation due to the shape is used as the lug input. The validity of this model was examined through comparison with experimental values obtained in a previous study on a small rolling equipment. As the result, the peak of frequency was same as the first-order lag excitation frequency and the frequency variation with rotation speed was also confirmed. However, resonance phenome caused the coincidence of lug excitation frequency and tire natural frequency could not expressed.