| 摘要 |
A run-flat tire comprises a carcass ply extending between the bead portions, and a sidewall reinforcing layer disposed axially inside said carcass ply in each sidewall portion, wherein in a normally inflated unloaded state, a profile line from a tire equator point (P) to a maximum tire section width point (D) is curved substantially along an involute curve so as to have a radius of curvature decreasing continuously from the tire equator point towards the sidewall portion, the basic circle of the involute curve is an ellipse whose major axis extends in the tire radial direction, the radial distance (h) between the tire equator point (P) and the maximum tire section width point (D) is more than 34% but less than 50% of the tire section height (H). In a x-y coordinate system which is defined in a meridian section of the tire such that: y-axis extends radially outwardly on the tire equator; x-axis extends axially outwardly in the tire axial direction; the x-y coordinates of said tire equator point (P) is (0, B); B is a radius of curvature of the profile line at the tire equator point (P), the elliptic function of the ellipse iswherein 0<a<b. |
