Improvement of the tractive performance of cage wheel lugs by enamel coating

Abstract

Previous work has shown that enamel coating on cage wheel lugs can significantly reduce soil sticking to the lugs, reducing the possibility of cage wheels blocking with soil. However, the effect of enamel coating on lug forces was unknown. Experiments were conducted, to study the effect of enamel coating on lug forces in a laboratory soil bin as well as in actual field conditions. In both experiments the soil used was a heavy clay soil. The lug surfaces were coated with enamel and their performance was compared with that of uncoated lugs. During the laboratory studies it was observed that at constant sinkage and soil moisture content, the lug forces generated by the enamel coated lug did not differ significantly from those generated by the uncoated lug. An increase in lug sinkage caused an increase in the lug forces while an increase in soil moisture content caused a decrease in lug forces. During the field studies, in different soil conditions, it was observed that the pull of the power tiller's wheels fitted with enamel coated lugs at any level of slip was higher than that of wheels fitted with uncoated lugs. The mean values of pull at 100% slip for enamel coated lugs were about 6% higher than that for the uncoated lugs. The differences between the maximum power transmitted for uncoated and coated cage wheel lugs were not statistically significant. Cage wheel blocking during field trials was never observed in the case of enamel coated lugs but blocking was quite frequent with uncoated cage wheel lugs.