| 摘要 |
PURPOSE:To efficiently restrain partial wear by approximating the surface contour of a tread to a specified reference line, and respectively specifying the radius of curvature at the center part and the side part of the tread, the radius of curvature and the effective width of a belt layer, and the deflection width and the pitch of a longitudinal groove. CONSTITUTION:The surface contour of a tread part is approximated to a reference curve L containing a center part L1 of radius of curvature R1 having the center on the equator CO of a tire and a side part L2 smoothly continued to the former and of radius of curvature R2 of length of 0.05-0.09 times of the radius of curvature R1. Meanwhile, the inside face of a belt layer 9 is laid along a circular arc having radius of curvature R3 of 400-800mm. The above- stated radius of curvature R1 is set as 1.6-2.2 times of the sectional width of the tire and smaller than the radius of curvature R3. Further, the effective width BW of the belt layer 9 is set as 0.6-0.75 times of the sectional width of the tire. The deflection width (b) of the longitudinal groove G is as 0.25-0.35 times of a rib width (a), and the pitch length P is as 4.5-6.5 times of the deflection width (b) respectively set. |
