TIRE INCLUDING A TREAD PROVIDED WITH INCISIONS INCLUDING WIDE PORTIONS AND NARROW PROTIONS

摘要

Tyre comprising a tread, this tread including a rolling surface (12) intended to come into contact with the ground, at least one circumferential row of upstanding elements (11), these upstanding elements (11) being separated from one another in the circumferential direction by incisions (20) of transverse or substantially transverse orientation, each incision (20) of transverse or substantially transverse orientation leading onto the rolling surface (12) and having a depth P, each incision (20) forming, on the rolling surface of the tyre when new, two facing edges (21, 22), these edges (21, 22) delimiting at least one narrow portion (30) of the incision, i.e. a portion having a mean width LE less than or equal to 2 mm, and at least one wide portion (40) of the incision, i.e. a portion having a mean width LL greater than 2 mm, these wide and narrow portions being disposed alternately, each narrow portion (30) and each wide portion (40) extending the full depth P of the incision (20), each narrow portion (30) having a volume uniformly distributed over the full depth P of the incision, each wide portion (40) having a volume for the most part between half the depth P of the cut-out and the depth P, this tread being characterized in that the following condition is satisfied:; 0.90×E/R(sum LE)/Pr1.10×E/R, in which:(sum LE) is the sum of the mean widths LE of the narrow portions of all the incisions separating the upstanding elements of the same row on a circle centred on the rotation axis of the tyre,R is the mean radius of the circle centred on the rotation axis on the rolling surface of the row concerned when new and Pr is the mean perimeter of the circle centred on the rotation axis and passing through a circumferential series of incisions in accordance with the invention,E is the mean thickness of the tread at the level of the row concerned.