The Load-Deflection and Rolling Characteristics of Polyurethane Wheels

This paper reports experimental work confirming the validity of a wheel load-deflection equation for polyurethane elastomer systems in terms of load, elastic modulus, and wheel geometry. A rolling resistance equation incorporating an energy loss factor in addition to the above parameters was also confirmed experimentally. For convenience of application an equivalence loading index table was constructed to simplify comparison of the load carrying capacities of rubber and polyurethane wheels at equal deflections in terms of the elastomer hardness values. Evaluation of the rolling resistance equation for polyester and polyether based polyurethane wheels showed that, by a proper choice of the parameters, wheels of either polyurethane system could be made which had equivalent rolling resistances. Experimental confirmation is shown. The dependence of rolling resistance on the temperature and frequency of wheel rotation is also considered.