Abstract
The applicability of theoretical equation of camber thrust, based on the theory of E. Fiala, to the side force at any side slip angle between 0° and 90° on the tractor tire was investigated using an apparatus mounted with smooth on agricultural tire.
Main results were as followes:
1. The relation between side force (S) included camber thrust and side slip angle (β) was expressed as follows:
When 0°≤β≤βn,
S={-a0C/3+Ctanβ-C2tan2β/3f+a0C(2-μ/f)+C3tan3β/3(3f+a0C)2(3-2μ/f)}W
and when βn<β≤90°,
S={μ-a0C/3(1-μ/f)}W
βn=tan-1(3f+a0C/C), a0=l/2rsinγ, f=coefficient of maximum friction, μ=coefficient of dynamic friction, W=supporting weight, C=a factor of cornering coefficient, r=radius of tire, l=length of ground contact of tire, γ=camber angle.
2. Using the chi-square test, the hypothesis that the side force calculated from the theoretical equation was equal to the experimental value of both rolling ahd driving wheel is acceptable at a level of 0.01.
3. Variations of the value of C affected by camber thrust was not so large at rolling wheel and positive camber angle of driving wheel but large with increase of negative camber angle of driving wheel and there was a peak camber angle. between -15° and -18°
4. Coefficient of camber thrust of smooth tire was the same value as that of automobile tire and larger than that of agricultural tire.
5. The side slip angle which made side force to zero by the operation of camber thrust became so small as one-tenth of the camber angle and the value was larger than that of automobile tire.
