| 摘要 |
<p>PURPOSE: To suppress the occurrence of looseness at a bead part by minimizing the deformation quantity of the based apex, by setting the max. width position height on the sectional surface of a lower region profile on the sectional surface of a tire having a flatness rate of 80-105%, bulge inclination, and the bead apex inclination to their respective specific values. CONSTITUTION: A lower region profile 10 outside the bead base line BL on the inside in the radial direction from the max. width position M on the sectional surface of a tire having the flatness rate of 80-105% in a standard state is determined. Accordingly, the bulging-out inclination H/L, i.e., the ratio between the max. position height H on the section ranging from the line BL to the position M and the tire bulge width L in 1/2 of the length in the subtraction of rim width B from the width MW on the tire section is set tp 2.0-3.0. Further, the length (h) in the vertical direction of the inclination line 11 joining the upper and the lower parts of the thick center line CL of the bead apex 9 is set to 45-65% of the height H, and the bead apex inclination h/w, i.e., the ratio between the length (h) and the length (w) in the horizontal direction of the inclination line 11 is set to 1.2-2.0. Accordingly, the generation of loose at the bead part due to the high load and the load variation is suppressed, and the durability can be improved.</p> |
