Tread pattern and method of manufacture
AssigneeCompagnie Generale des Establissements Michelin-Michelin & Cie
InventorsBertrand Garnier De Labareyre, Jose Merino Lopez
Life of this patent
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Abstract
A tread for a tire, the tread being provided with a plurality of cutouts, defined by walls perpendicular to or oblique to the rolling surface of the tread, in which the two main walls of at least one cutout located in the part of the tread affected by the loading on the ground of the tire during travel are connected by at least one rubber connecting element and in that the total connection surface SE of the connecting element(s) is at most 80% of the surface defined by the geometric contour L of minimum length and surrounding said total connection surface SE. A method for producing a cutout provided with at least one connecting element.
Claims45
A tread of thickness E for a tire, provided with a rolling surface, said tread being provided with a plurality of cutouts, each cutout being defined by the space defined principally between two main opposing walls, said walls being perpendicular to or oblique to the rolling surface, and having a depth h, measured as the maximum radial distance between the points of the walls of said cutout which are radially farthest away, at most equal to the thickness E of the tread, characterized in that:
- the two main opposing walls of at least one cutout located in the part of the tread affected by the loading on the ground of the tire during travel are connected by at least two rubber connecting elements, the connecting elements having with each of the walls a total interconnection surface SE, said total interconnection surface SE on each of the walls being at least 10% of the total surface ST of said wall,
- all the points of the outer contour of the surface of intersection of at least one connecting element with one of the walls are located at a distance from the rolling surface which is less than the depth of the cutout,
- and, on each of the walls, the total interconnection surface SE is at most 80% of the surface SG, the surface SG being equal to the surface, measured on said wall of the cutout, defined by a geometric contour L of minimum length and enveloping all the interconnections.
A tread of thickness E for a tire, provided with a rolling surface, said tread being provided with a plurality of cutouts oriented virtually in the same direction, each of said cutouts being defined by the space defined principally between two main opposing walls, said walls being perpendicular to or oblique to the rolling surface, and having a width e and a depth h, measured as the distance in a radial direction between the points of the walls of said cutout which are closest to the rolling surface and the points of said walls which are farthest away from the rolling surface of the new tire, at most equal to the thickness E of the tread, said cutouts being spaced by an average pitch equal to p, said tread being characterized in that:
- the two main opposing walls of a plurality of cutouts are connected by at least two rubber connecting elements, the connecting elements having a total interconnection surface SE with each of the walls;
- and in that the connecting ratio TP=SE/ST, ST representing the total surface of one of the main walls of said cutout, between the main walls of one and the same cutout is at least 0.10 and at most equal to the following value:
- 1 ( 1 + 1 3 ε ) 0.75 with ε = ( p - e ) / h .
A method for manufacturing a tread of thickness E for a tire, said tread being provided with a plurality of cutouts provided with at least one connecting element between main opposing walls of each of said cutouts, comprising the following steps:
- production of inserts of a material capable of later removal from a cutout, said inserts having a form generally the same as the cutouts desired in the tread, and of thickness equal to the width of said cutouts;
- removal of material in each insert to obtain (an) orifice(s) in a distribution selected beforehand, each orifice having a shape equivalent to the cross-section of a connecting element between two main walls of one and the same cutout;
- insertion of the inserts into a non-vulcanized strip of rubber;
- molding, in a mold having the dimensions of the tread, and vulcanizing said tread and forming the connecting elements in the orifice(s) of the inserts;
- demolding the tread after vulcanization.
A tread of thickness E for a tire, provided with a rolling surface, said tread being provided with a plurality of cutouts, each cutout being defined by the space defined principally between two main opposing walls, said walls being perpendicular to or oblique to the rolling surface, and having a depth h, measured as the maximum radial distance measured between the points of the walls of said cutout which are radially farthest away, at most equal to the thickness E of the tread, characterized in that:
- the two main opposing walls of at least one cutout located in the part of the tread affected by the loading on the ground of the tire during travel are connected by one rubber connecting element, this connecting element having with each of the walls a total interconnection surface SE, said total interconnection surface SE on each of the walls being at least 15% of the total surface ST of said wall and at most 40% of the said total surface ST,
- all the points of the outer contour of the surface of intersection of the connecting element with one of the walls are located at a distance from the rolling surface which is strictly less than the depth of the cutout,
- and the surface SG, equal to the surface, measured on said wall of the cutout, defined by the geometric contour L of minimum length and enveloping the total interconnection surface SE, is at least 90% of the total surface ST of said wall.
A tread of thickness E for a tire, provided with a rolling surface, said tread being provided with a plurality of cutouts oriented virtually in the same direction, each of said cutouts being defined by the space defined principally between two main opposing walls, said walls being perpendicular to or oblique to the rolling surface, said cutouts having a depth h, measured as the distance in a radial direction between the points of the walls of said cutout which are closest to the rolling surface and the points of said walls which are farthest away from the rolling surface of the new tire, h being at most equal to the thickness E of the tread, said cutouts being spaced by an average pitch equal to p, said tread being characterized in that:
- the two main opposing walls of the cutouts are connected by at least one rubber connecting element, the connecting element(s) having a total interconnection surface SE with each of the walls;
- the connecting rate TP=SE/ST for each cutout is at least 0.10 and at most 0.80, SE being equal to the total interconnection surface of the connecting element(s) on each of the walls, ST representing the total surface of each main wall of said cutout;
- and
- the ratio p/h, satisfies the following equation:
- p h ≥ 1 5 ( 1 T P ) 0.75 .
Dependencies are inferred from the claim text.