| 摘要 |
<p>Conventionally, when a pneumatic tire having a pair of one-side open sipes which are formed substantially along the transversal grooves, whose one ends are alternately opened in circumferential grooves on the opposite sides, and whose depth is different from that of the grooves formed in the direction of the tire width is cured and molded, the surface layer of rubber is caught between the sipe forming blades formed on a curing mold, and creases are produced causing flow cracks. In order to solve this problem, the depth (D) in millimeters of the cross sipe, which is the depth of the one-side open sipe with respect to the bottom of the widthwise grooves, is so determined as to satisfy the inequality: D ≤ (a/w x 50) - 18, where a is the shortest distance between the sipes at the bottom thereof; w is the distance, parallel to the shortest distance a, from the block edge of the non-opened portion of the sipe to the end portion at the farthest position; and the ratio a/w the sipe spacing index.</p> |
