Studies on the Running Resistance of Wheel Having the Angle for the Traveling Direction (1)
Relation between the Running Resistance and the Deflection Angle
1966 Volume 28 Issue 3 Pages 136-140
Details
1966 Volume 28 Issue 3 Pages 136-140
Any tractor does not always travel the same direction as it's wheels revolve. Especially on the hilly land, the wheels must be kept to have the upper deflection angle for the contour line not to slip down. This report is the experimental results of the running resistances of wheels having the deflection angle (α).
On the case of pulling the tractor with another one, traction force needed—traction resistance—is expressed in form of eq. (1), and the side force (Sr) is in form of eq. (2), which obtained in the cause of the revolution of wheels.
D=K1Wsinα (1)
Sr=K2WsinAα1/B (2)
Where, W is the weight of tractor.
K1 and K2 are the coefficients. Those are not variable by the size and load of the tires, but variable by the road conditon.
When the test tractor drives by himself pulling some of loads (P), the maximum traction force (Pmax) and the side force (Sp(n)) are expressed in form of eq. (3) and (4) respectively.
Pmax=K3Wcosα (3)
Sp(n)=K4Wsinα+Sr(1-P/Pmax)(1-α/90) (4)
Where, K3 and K4 are the coefficients having the same characters of K1 and K2.
The force ratios on the each load for traveling direction were the minimum values in 30-40 degrees of the deflection angle, and the larger the traction force were, the higher they were. On the other hand, the side force ratios were higher for the smaller traction forces and the smaller deflection angles, and the larger the traction forces and deflection angles were, the less they were.
The traction efficiency was maximum value for about 0.3 in the coefficient of traction at 0 degree of the deflection angle.
As the running resistance of wheels, having the deflection angle, were larger and the traction efficincies were lower like above than we supposed, many effective studies concerning with the better design of wheels, the better using and improvement of tractors and others are expected to reduce the value of the deflection angle.
