| 摘要 |
PURPOSE:To improve the high-speed durability of a tire by arranging the radii of curvature to be different between the center forming part and shoulder forming part on the inner surface of a tire tread and larger than the radius of curvature of a virtual circular arc which has its center on the center line of the tire. CONSTITUTION:The tread forming part 1 of a mold for molding a tire comprises a center forming part 2, a shoulder forming part 3, and a main groove forming part 4. In the cross section of a tire including the rotary shaft, the forming parts 3, 4 draw the first and second circular arcs having different radii of curvature R1 and R2. The first circular arc and the tire center line O-O' cross at P1, while the second circular arc and the third circular arc with a radius of curvature R3 connecting the outer end of the forming part 3 and the upper end of the inner surface of a sidewall forming part 5 cross at P3. R1 and R2 are larger than the radius of curvature Rave of a virtual circular arc which has its center Q on the center line O-O'. In this way, the high-speed durability of the tire improves and the local abrasion of the tire can be prevented. |
