Mould Element For A Tire Mould Comprising A Mark

1 . A mould element for a mould for a tire comprising a marking, the mould comprising a shell adapted to mould the sidewall of the tire, said mould element being a removable insert adapted to be mounted in a housing of said shell, and said marking being adapted to mould on the tire a coded matrix symbol that contrasts with the sidewall of the tire, said marking comprising a first set of cavities or of protuberances which is configured to mould dark parts of the coded matrix symbol.

2 . The mould element according to claim 1 , wherein the marking comprises a second set of protuberances projecting from said mould element and configured to mould light parts of the coded matrix symbol and wherein said protuberances have the shape of caps of a sphere, each protruding element being interpenetrated by several adjacent protruding elements.

3 . The mould element according to claim 1 , wherein the marking comprises a set of set-back recesses configured to mould light parts of the coded matrix symbol and wherein said set-back recesses have the shape of caps of a sphere.

4 . The mould element according to claim 1 , wherein said mould element comprises a second set of cavities which is configured to mould a demarcation zone delineating the coded matrix symbol.

5 . The mould element according to claim 1 , wherein the cavities of the first set of cavities have a conical shape and are distributed through the marking at a density at least equal to one cone per square millimetre (mm 2 ), each cone having a mean cross section comprised between 0.0005 mm 2 and 1 mm 2 .

6 . The mould element according to claim 1 , wherein the cavities of the first set of cavities have a form of substantially mutually parallel striations, the spacing of the striations being at most equal to 0.5 mm, each striation having a mean width comprised between 0.02 mm and 0.25 mm.

7 . The mould element according to claim 1 , wherein the cavities of the first set of cavities have a parallelepiped shape of a side length comprised between 0.05 mm and 0.5 mm, of a depth comprised between 0.05 mm and 0.5 mm, the distance between two adjacent cavities in the marking being comprised between 0.05 mm and 0.5 mm.

8 . The mould element according to claim 1 , wherein the protuberances of the first set of protuberances have a conical shape and are distributed through the marking at a density at least equal to one protuberance per square millimetre (mm 2 ), these protuberances having equivalent diameters comprised between 0.01 mm and 1.2 mm.

9 . A mould for a tire comprising a shell adapted to mould the sidewall of the tire, wherein the shell comprises a housing in which is mounted a mould element according to claim 1 .

10 . A method of manufacturing a mould element for a mould for a tire, the mould comprising a shell adapted to mould the sidewall of the tire, said mould element being a removable insert adapted to be mounted in a housing of said shell and comprising a marking, wherein the method comprises:

extraction of said mould element from a sheet of aluminium;

creation of the marking adapted to mould, on the tire, a coded matrix symbol that contrasts with the sidewall of the tire, said coded matrix symbol comprising dark parts and light parts, the creation of said marking comprising:

creation of the marking suited to moulding the light parts of the coded matrix symbol in said mould element; and

creation of the marking suited to moulding the dark parts of the coded matrix symbol in said mould element.

11 . The method of manufacture according to claim 10 , wherein the steps of creating the marking suited to moulding the light parts and the dark parts of the coded matrix symbol in said mould element are performed simultaneously by pressing said mould element.

12 . The method of manufacture according to claim 10 , wherein the creation of the marking suited to moulding the light parts of the coded matrix symbol in said mould element is performed before the extraction of said mould element from the sheet of aluminium.

13 . The method of manufacture according to claim 10 , wherein the creation of the marking suited to moulding the light parts of the coded matrix symbol is carried out:

by a surface treatment of said mould element so that the surface of said mould element corresponds to said light parts; or

by micro shot peening of the second set of protuberances projecting from said mould element to form the marking of the coded matrix symbol so that said protuberances have the shape of caps of a sphere, each said protruding element being interpenetrated in the marking by several adjacent protruding elements, the second set of protuberances being configured for moulding said light parts of the coded matrix symbol; or

by moulding of a set-back set of recesses having the shape of caps of a sphere, said set of recesses being configured for moulding said light parts of the coded matrix symbol.

14 . The method of manufacture according to claim 13 , wherein the micro shot peening creates microbeads of a diameter comprised between 10 μm and 200 μm.

15 . The method of manufacture according to claim 10 , wherein the creation of the marking configured for moulding the dark parts of the coded matrix symbol in said mould element is performed by creating a first set of cavities or of protuberances in said mould element configured for moulding said dark parts of the coded matrix symbol, the creation of the first set of cavities in said mould element being carried out by laser etching and the creation of the first set of protuberances in said mould element being performed by moulding.