Basic Studies on the Resistance Received by a Wheel Rolling on a Soft Ground

Abstract

In this report, description is first made from the results of experiments made by the electrical, automatic M-T (Mashima-Takahashi) wheel rolling resistance measuring device. The Takahashi's theoretical equation, based on the experimental results, are then derived which show the relations among the resultant rolling resistance R received by the wheel from soft ground (S. G.), its horizontal component H and vertical component V, the direction θ, the coordinates (X, Y) of the point Q where the force is applied, the driving torque of wheel M, etc., on one hand and the breadth of wheel b, the wheel diameter 2r, the sinking depth at the lowermost end of wheel y0, the characteristic constants of S. G. sample k and n, coefficient of friction μ, etc., on the other hand. It is explained that these formulas represented in vector are convenient for practical purposes. From the formulas, it is also found that the values of R, H, V, θ, Q (X, Y), etc. differ between the two cases, i.e. when the wheel is pulled and the wheel rotates under axial driving. Finally, the theoretical formulas on the rolling resistance of a vehicle running on S. G. are obtained from the formulas for a single wheel. Applications of the studies for practical purposes are also described.