Tire tread for heavy vehicle of construction plant tire
View Patent ↗Tire ( 1 ) for a heavy vehicle of construction plant type with tread ( 2 ) comprising raised elements ( 3 ), separated by grooves ( 4 ), extending radially outwards from a bottom surface ( 5 ) as far as a contact face ( 6 ) over a height (H) and comprising base compound ( 9 ) and coating compound ( 10 ). Coating compound ( 10 ) has a constant maximum thickness (e max ), at the contact face ( 6 ) of each raised element ( 3 ), at most equal to 0.15 H, the coating compound ( 10 ) has a constant minimum thickness (e min ), at each groove bottom ( 8 ), at least equal to 0.04 H, and the elongation at break at 23° C. A R2 of the coating compound ( 10 ) is at least equal to 1.05 times the elongation at break of 23° C. A R1 of the base compound ( 9 ).
1. A tire for a heavy vehicle of construction plant type, comprising:
a tread comprising raised elements separated by grooves;
each raised element extending radially outwards from a bottom surface as far as a contact face over a height H and comprising lateral faces;
each said groove being a cut in the tread which cut is delimited laterally by lateral faces of raised elements that face one another and is delimited radially towards the inside by a groove bottom resting on the bottom surface;
the tread comprising a base compound comprising at least one first elastomeric compound, and a coating compound comprising at least one second elastomeric compound, the coating compound fully covering the base compound;
the base compound and coating compound respectively having elongations at break at 23° C. A R1 and A R2 ;
wherein the coating compound has a constant maximum thickness e max , at the contact face of each raised element, at most equal to 0.15 times the height H of the raised element,
wherein the coating compound has a constant minimum thickness e min , at each groove bottom, at least equal to 0.04 times the height H of the raised element,
wherein the constant maximum thickness e max , at the contact face is greater than the constant minimum thickness e min at each groove bottom, and
wherein the elongation at break at 23° C. A R2 of the coating compound is at least equal to 1. 05 times the elongation at break at 23° C. A R1 of the base compound.
2. The tire for a heavy vehicle of construction plant type according to claim 1 , wherein the minimum thickness e min of the coating compound at each groove bottom is at least equal to 1 mm.
3. The tire for a heavy vehicle of construction plant type according to claim 1 , wherein the maximum thickness e max of the coating compound at the contact face of each raised element is at most equal to 10 mm.
4. The tire for a heavy vehicle of construction plant type according to claim 1 , wherein the elongation at break at 23° C. A R2 of the coating compound is at least equal to 1.08 times the elongation at break at 23° C. A R1 of the base compound.
5. The tire for a heavy vehicle of construction plant type according to claim 1 , wherein the base compound contains a diene elastomer of natural rubber (NR) type.
6. The tire for a heavy vehicle of construction plant type according to claim 1 , wherein the coating compound comprises a blend of diene elastomers of NR/SBR or NR/BR/SBR type, NR denoting a natural rubber, BR a polybutadiene and SBR a stirene-butadiene copolymer.
7. The tire for a heavy vehicle of construction plant type according to claim 1 , wherein the thickness of the coating compound on the lateral faces decreases from the contact face to each groove bottom.