Assessment of the influence of the eccentricity of tires on the whole-body vibration of tractor drivers during transport on asphalt roads

Agricultural vehicle operators are exposed to high levels of whole body vibrations (WBVs) which are related, above all, to surface irregularities, forward speed and vehicle setting. European Parliament Directive 2002/44/EEC sets the minimum requirements for the protection of workers from risks to their health and safety due to exposure to mechanical vibrations, and it is therefore of utmost to investigate any source of vibration during agricultural works and any machine-related transmission element. Tractor tires play a key role in damping vibrations; their response varies according to the tractor mass and tire inflation pressure and, during transport, they have to be taken into account at different forward speeds. The eccentricity of the tire is one of the factors thus influences the amplitude of the solicitations acting on the tire. This study was aimed at evaluating the influence of the “tire eccentricity” parameter on driver comfort and at introducing a test method for its assessment for validation purposes.