Deflection and Contact Characteristics of a Power Tiller Tyre

The power tillers or hand tractors are extensively used by small (1-2 ha holdings) and medium (2-4 ha holdings) farmers in predominantly rice-growing states in India for roto-tilling, plowing, puddling, intercultivation, harvesting, transportation etc. The vertical deflection and contact area of a pneumatic tyre (6.00 x 12 - 4 ply rating) of a popular 6.7 kW power tiller were determined at 2.38-2.87 kN normal loads and 80-200 kPa inflation pressure on a rigid flat surface. Both deflection and contact area varied linearly with inflation pressure in the range of normal loads selected for the study. The empirical equations were developed to predict the deflection and contact area of the tyre. Further, the power tiller tyre considered for the study followed the modified universal characteristics of a tyre. However, both empirical equations and universal characteristics equation of tyres could be used to predict tyre behaviour under various operational parameters.