Studies on the Driving Performance of Walking Tractor (I)

Characteristics of Horizontal Traction

Abstract

The horizontal traction performances of walking tractor were compared on road and cultivated land. In the tests, the tractive forces, the travel speeds, the torques and revolutions of wheel shaft and the loads on the driving wheel and steering handle were measured at different load on the driving wheel and travel speeds. The experimental results which were obtained in the way described above were shown in the nondimensional parameters (the coefficient of traction; μ, the coefficient of driving force; μ_t, the coefficient of weight transfer on the driving wheel; k, the coefficient of rolling resistance; ρ, the force ratio; ν, the tractive power coefficient; π, the tractive efficieney: η and the travel reduction; s). The characterietics of the horizontal traction were summarized as follows.
(1) Both the tractive forces and tractive powers increased when the loads on the driving wheel were heavier on road and cultivated land, but it was recognized that these experimental values were agreed when the experimental results were shown in the nondimentional parameters.
(2) The traction performance on the road was better than that on the cultivated land because the rolling resistances on the cultivated land were lager than those on the road.
(3) As an example, the nondimentional factors at the travel reduction of 0.3 on the cultivated. land were as follows: μ=0.62, μ_t=0.85, k=-0.19, ρ=0.22, ν=0.73, π=0.44, η=0.52
(4) On the cultivated land, the tractive power coefficient became maximum of 0.44 at the coefficient of tration of 0.62 (the travel reduction 0.28), and the tractive efficiency became maximum of 0.57 at the coefficient of traction of 0.43 (the travel reduction 0.17).