| 摘要 |
PURPOSE:To improve the traction performance in a muddy ground surface and enable the pneumatic tire to conform with the field operation, by specifying the trochoidal locus at the tip of the side wall of the lug on the grounding side, regarding the sectional configuration of the lugs with respect to a section parallel to the equatorial plane of the pneumatic tire. CONSTITUTION:Regarding the sectional configuration of the lug with respect to a section parallel to the equatorial plane of a tire, the trochoidal locus of a side-wall tip A of the lug on the grounding side as viewed when the tire rolls is expressed by the following expression. Namely, the expression: XA= rA{(1-S)t-sin t}, YA=rA(1-cos t). At this time, the locus (XB, YB) of a given point B on the side wall at the grounding side, when YB=YA, is set to be substantially equal to XB=XA or smaller than this with respect to the locus of the side-wall tip A while, on the other hand, the angle alpha defined between a line portion AB connecting the points A and B and the radial direction of the tire is set to be alpha>0. In this case, S represents the slip ratio and is set to be S=0.1, (t) represents the rotating angle when the tire rolls and is set to be -0.614<=t<=0, and rA represents the radius at the tip point A as viewed from the rotating shaft of the tire. |
