Tread Comprising A Strong-Contrast Texture In A Groove
A tread ( 2 ), said tread having a tread surface ( 20 ) and a plurality of grooves ( 21 ), at least one groove having, in cross section, an undulating overall shape with entirely open groove parts ( 210 ) at the tread surface ( 20 ) and completely or partially closed groove parts ( 211 ) at said tread surface ( 20 ). The tire is characterized in that the open groove parts ( 210 ) comprise a contrasting texture ( 3 ) in the tread, the texture ( 3 ) having a plurality of elements that protrude from or are recessed into the surface of the groove. The texture ( 3 ) is absent from the closed groove parts ( 211 ).
1 . A tread for a tire, said tread having a tread surface and a plurality of grooves, at least one of said grooves having, in cross section, an undulating overall shape with entirely open groove parts at the tread surface and completely or partially closed groove parts at said tread surface, wherein the open groove parts comprise a contrasting texture in the tread, the texture having a plurality of elements that protrude from or are recessed into the surface of the groove, and wherein the texture is absent from the closed groove parts.
2 . The tread according to claim 1 , wherein at least 30% of the protruding elements of the texture form an angle α of greater than 40° with respect to a plane tangent to the surface of the groove, and wherein at most 25% of the protruding elements of the texture form an angle α of less than 20° with respect to the tangent plane.
3 . The tread according to claim 1 , wherein all or some of the protruding elements are strands distributed through the texture at a density at least equal to one strand per square millimetre (mm 2 ), each strand having a mean cross section of between 0.003 mm 2 and 1 mm 2 .
4 . The tread according to claim 1 , wherein all or some of the protruding elements are substantially mutually parallel lamellae, the spacing of the lamellae in the texture being at most equal to 0.5 mm, each lamella having a mean width of between 0.03 mm and 0.25 mm.
5 . The tread according to claim 1 , wherein all or some of the protruding elements form parallelepipeds having a side length of between 0.05 mm and 0.5 mm and a height of between 0.05 mm and 0.5 mm, the distance between two adjacent parallelepipeds in the texture being between 0.05 mm and 0.5 mm.
6 . The tread according to claim 1 , wherein the protruding elements have variable shapes and distances between protruding elements in the texture.
7 . The tread according to claim 1 , wherein the recessed elements form openings in the surface of the groove and the texture comprises a plurality of openings, these openings being distributed through the texture at a density at least equal to one opening per square millimetre (mm 2 ), these openings having equivalent diameters of between 0.03 mm and 1.2 mm.
8 . A tire comprising the tread according to claim 1 .