| 摘要 |
<p>The invention concerns a running tread comprising a tread design consisting of at least two ribs, of average length L, comprising a plurality of grooves whereof the traces on the contact surface extend between two intersection points A and B, the segment AB forming an angle α with the transverse direction of the tread of not more than 40°. Said tread is characterised in that each groove of average length E, comprises a succession of groove portions, some of said groove portions having, on the entire surface parallel to the unused contact surface and included between said unused surface and two-thirds of the groove maximum depth, traces forming a mean angle β not more than 15° with the longitudinal direction of the tread, said portions having a total length Lt which is not less than one-fifth of the width of the rib, and the groove portions, whereof the traces form an angle β are provided on the opposite walls with raised patterns of amplitude K designed to co-operate mutually to block the relative movements of a wall of the groove relative to the opposite wall, the amplitude K of said raised patterns ranging between 4 and 10 times the average width E of the groove.</p> |
