| 摘要 |
Tread for a tire for a heavy goods vehicle of total thickness E and of total volume V, having at least one continuous groove comprising: at least two wearing layers in the thickness of the tread, each having a thickness at most equal to 75% of the total thickness E of the tread, a plurality of external cavities and a plurality of internal cavities positioned radially and entirely on the inside of the tread surface in the new state, each internal cavity being connected to an external cavity by a connecting channel, and having a total voids volume Vc at least equal to 7% and at most equal to 12% of a volume equal to the sum of the total volume V and of the total voids volume, and having an effective voids volume Ve for each wearing layer less than the total voids volume Vc, and satisfying the equation: 0.4 St<Ve<0.8 St, wherein 0.4 and 0.8 are heights in millimetres and St is the surface delimited by the external contour of the contact patch under static conditions under service load and pressure, and at least the first wearing layer I is made up of a rubber compound based on at least one material having a dynamic Tg higher than−40° C. and predominantly containing a SBR copolymer of Tg>−65° C. |
