Tire featuring a complex, wear-resistant tread

Abstract

The tire (10) comprises a tread including a tread layer (52) comprising an axially central portion (P0c) and an axially lateral portion (P1c, P2c). The axially central portion (P0c) and the axially lateral portion (P1c, P2c) of the tread layer (52) comprise, respectively, a central material (M0) and a lateral material (M1, M2) having, respectively, a dynamic shear modulus G*C, G*1 such that G*1

Description

Title of the invention: Tire comprising a complex wear-resistant tread

[0001] The present invention relates to a tire, particularly for passenger vehicles. A tire is defined as a band designed to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure greater than atmospheric pressure. A tire according to the invention has a substantially toroidal structure of revolution about a principal axis of the tire.

[0002] Prior art tires comprising a tread comprising a tread layer comprising an axially central portion of the tread layer and first and second axially lateral portions of the tread layer arranged axially outside and on either side of the axially central portion of the tread layer. In order to optimize certain tire performance characteristics, for example, rolling resistance and / or drift stiffness, the axially central portion of the tread layer and each first and second axially lateral portion of the tread layer comprise, respectively, a central material and first and second lateral materials having, respectively, a dynamic shear modulus at 23°CG*C, G*1, G*2 such that G*1 <G*C et G*2<G*C.

[0003] It has been observed that this tire reaches maximum wear on each of the first and second axially lateral portions of the tread before reaching it on the axially central portion of the tread. Thus, a tire user is forced to change the tire even though there is still a significant thickness of tread remaining in the axially central portion of the tread.

[0004] The invention aims to delay the wear of the tread layer in at least one of the first and second axially lateral portions of the tread layer in order to delay the replacement of the tire.

[0005] To this end, the invention relates to a tire comprising a crown including a tread carrying a tread surface and a crown reinforcement arranged radially inside the tread, the tread comprising a tread layer comprising an axially central portion of the tread layer and an axially lateral portion of the tread layer arranged axially outside the axially central portion of the tread layer, the axially central portion and the axially lateral portion of the wearing course comprise respectively a central material and a lateral material having respectively a dynamic shear modulus G*C, G*1 such that G*1 <G*C, chaque module dynamique en cisaillement G*C, G*1 étant mesuré à 23°C à 10% de déformation et à une fréquence de 10 Hz selon la norme ASTM D 5992 - 96, la bande de roulement comprenant une portion axialement centrale de la bande de roulement et des première et deuxième portions axialement latérales de la bande de roulement agencées axialement à l’extérieur et de part et d’autre de la portion axialement centrale de la bande de roulement,the tread comprises principal circumferential cutouts having a depth greater than or equal to 50% of the tread height, comprising first and second axially external principal circumferential cutouts arranged axially on either side of the median plane of the tire, the first and second axially external principal circumferential cutouts being the outermost axially external principal circumferential cutouts of the tread, each first and second axially lateral portion of the tread being arranged axially outside each first and second axially external principal circumferential cutout respectively, and the axially central portion of the tread extending from the first axially lateral portion of the tread to the second axially lateral portion of the tread, , the axially central portion of the wearing course being at least partly arranged within the axially central portion of the tread, the axially lateral portion of the wearing course being at least partly arranged in one of the first and second axially lateral portions of the tread, the apex reinforcement comprising a radially outermost layer and including reinforcing elements embedded in a polymer matrix, the average radial distance Elm in the axially central portion of the tread between: - the surface passing through the radially innermost point of the deepest cut made in the axially central portion of the tread and substantially parallel to the tread surface, and - the radially outer surface passing through the radially outermost points of the radially outermost reinforcing elements among the reinforcing elements of the radially outermost layer arranged vertically above the axially central portion of the tread, is such that Elm < 2.00 mm.

[0006] The tire according to the invention allows for more even axial wear of the tread and increases the distance the tire can travel before needing replacement. Furthermore, the tire also exhibits relatively low rolling resistance.

[0007] Indeed, the inventors of the invention understood that tire wear results from two different phenomena, one at the local level of the tread layer and the other at the overall level of the tread. Specifically, the inventors understood that local wear follows a rule whereby a portion of the tread layer with relatively high rigidity compared to its neighboring portions wears out more quickly than a portion of the tread layer with relatively low rigidity compared to its neighboring portions. The inventors also understood that overall wear, unlike local wear, follows a rule whereby the lower the rigidity of the tread, the more quickly it wears out.

[0008] Once these two rules were discovered, the inventors explain the more homogeneous wear of the tire according to the invention as follows. By using a lateral material with a relatively low shear dynamic modulus (in other words, low stiffness), the local stiffness of the axially lateral portion of the tread is reduced, which in turn reduces the wear of the axially lateral portion of the tread. However, the use of this lateral material with a relatively low shear dynamic modulus results in a reduction of the overall stiffness of the tread, thereby increasing the tread wear rate. To compensate for this faster overall wear, the inventors conceived the idea of ​​using a reduced average radial distance Elm, which makes the tread more rigid overall and thus reduces the overall wear rate.

[0009] The complex shear modulus G* is a dynamic property well known to those skilled in the art and is measured on a Metravib VA4000 or DMA+450 type viscoelastic analyzer using specimens comprising a baked composition extracted from tires. The response of the specimen subjected to a sinusoidal alternating simple shear load at a frequency of 10 Hz is recorded under determined temperature conditions (here 23°C) according to ASTM D1349-99. A strain amplitude sweep is performed from 0.1% cc to 100% cc (forward cycle), then from 100% cc to 0.1% cc (reverse cycle), cc meaning peak-to-peak. The specimen has a cylindrical cross-section as described in ASTM D 5992-96 (2011 re-approved version, originally approved in 1996) in Figure X2.1 (circular embodiment) and has a diameter of 10 mm [0 to +0.04 mm] and a thickness of 2 mm [1.83-2.33]. The complex dynamic shear modulus G* is defined. as the square root of the sum of the squares of G' and G'', where G' represents the elastic modulus and G'' represents the viscous modulus. The complex shear modulus G* is measured at 10% cc of strain on the return cycle.

[0010] The determination of the average radial distance Elm is carried out in the axially central portion of the tread by measuring, between the surfaces, several radial distances axially distributed over the axial width of the axially central portion of the tread. For example, a distance will be measured every centimeter along the axial direction starting from the first and second axial edges of the axially central portion of the tread. Obviously, if the outermost radial point of the outermost reinforcing element is radially outside the surface passing through the innermost radial point of the deepest cutout and substantially parallel to the tread surface, the measured radial distance is considered negative.Conversely, and in the vast majority of cases, if the outermost radially point of the outermost radially point of the reinforcement element is radially inside the surface passing through the innermost radially point of the deepest cutout(s) and substantially parallel to the running surface, the measured radial distance is considered positive.

[0011] These measurements will be taken in several meridian planes equally distributed around the circumference of the tire, for example in four meridian planes. The radial distances thus measured will then be averaged to obtain the average radial distance Elm.

[0012] By radial distance between two surfaces, we mean the straight distance between a point on one of the surfaces and its projection on the other of the surfaces along the radial direction of the tire.

[0013] By vertically aligned with the axially central portion of the tread, we mean the radially outer surface resulting from the projection along the radial direction of said axially central portion of the tread onto the radially outer surface passing through the outermost radially points of the outermost radially outer reinforcing elements among the reinforcing elements of the outermost radially layer.

[0014] The axially central portion of the tread layer includes the median plane of the tire.

[0015] Preferably, the axially central portion of the wearing course has an axial width strictly greater than the axial width of the or each axially lateral portion.

[0016] The wearing course is intended to come into contact with the ground when the A tire is considered new and at least until it reaches a predetermined wear threshold, such as a regulatory wear threshold. This regulatory wear threshold is indicated, in particular, by the presence of wear indicators in the tread. A layer that comes into contact with the ground when the tire has a level of wear exceeding the regulatory wear threshold is not considered a tread layer.

[0017] Conventionally, the tread surface is axially delimited by first and second axial edges coinciding respectively with the first and second axial edges of the tread. The first and second axial edges are determined on a tire mounted on a nominal rim and inflated to the nominal pressure as defined in the ETRTO 2023 standard manual. The first and second axial edges are arranged on either side of the median plane of the tire and are formed by lines substantially parallel to the circumferential direction of the tire. In the case of a clear boundary between the tread surface and the rest of the tire, the first and second axial edges are determined simply.In cases where the tread surface is continuous with the outer surfaces of the tire sidewalls, the first and second axial edges are usually determined by loading the tire to 80% of its load capacity according to the ETRTO 2023 standard manual, and the first and second axial edges are identified as the axial limits of the tread in contact with the ground.

[0018] A matrix is ​​said to be polymeric because it is based on a polymeric composition, this polymeric composition being able to include one or more polymers, for example chosen from thermoplastic polymers, thermosetting polymers, elastomers, thermoplastic elastomers, but also fillers and other components usually used in the field of tire compositions, in particular compositions for embedding reinforcement elements.

[0019] Preferably, the polymer matrix is ​​an elastomeric matrix. By elastomeric matrix is ​​meant a matrix exhibiting elastomeric behavior in the crosslinked state. Such a matrix is ​​advantageously obtained by crosslinking a composition comprising at least one elastomer and at least one other component. Preferably, the composition comprising at least one elastomer and at least one other component includes an elastomer, a crosslinking system, and a filler. The compositions used for these layers are conventional compositions for calendering reinforcements, typically based on natural rubber or another diene elastomer, a reinforcing filler such as carbon black, a vulcanizing system, and standard additives.The adhesion between the wire reinforcement elements and the matrix in which they are embedded is ensured for example by a conventional adhesive composition, for example an RFL type glue or equivalent glue such as by. example described in WO2013017421 or WO2017168109.

[0020] A reinforcing element is defined as an element that provides mechanical reinforcement to the polymer matrix in which it is intended to be embedded. Preferably, each reinforcing element is wire-like, meaning that each element has a length at least 10 times greater than the longest dimension of its cross-section, regardless of the shape of the latter: circular, elliptical, oblong, polygonal, and in particular rectangular, square, or oval. In the case of a rectangular cross-section, the wire-like reinforcing element is in the form of a strip.

[0021] A cutout or a portion of a cutout has two main characteristic dimensions: a width and a curvilinear length such that the curvilinear length is at least equal to twice the width. A cutout or a portion of a cutout is therefore delimited by at least two main lateral faces determining its curvilinear length and connected by a base, the two main lateral faces being separated from each other by a non-zero distance, called the width of the cutout or portion of the cutout.

[0022] The principal direction of a cutout is the direction along which the curve equidistant from each edge of the cutout to the radial dimension of the running surface passes. The curvilinear length is the length measured along this curve equidistant from each edge of the cutout to the radial dimension of the running surface, between each end of the cutout. The mean direction is the shortest curve joining the two ends of the cutout.

[0023] The width of a cut or portion of a cut is, in the case where the cut or portion of a cut does not include a chamfer, on a new tire, the distance between the two main side faces measured over the entire depth of the cut or portion. The width of a cut or portion of a cut is, in the case where the cut or portion of a cut includes a chamfer, on a new tire, the distance between the two main side faces measured over the entire depth of the cut or portion radially inside the chamfer. The width is measured substantially perpendicular to the main side faces. The minimum width of a cut or portion is the smallest width of the cut or portion in question.

[0024] The depth of a cut or portion of a cut on a new tire is the radial distance between the bottom of the cut or portion and its projection onto the ground when the tire is rolling. The maximum depth of a cut or portion is the greatest of the depths of the cut or portion in question.

[0025] The maximum depth of the cuts is called the tread depth. Preferably, the maximum depth of the main circumferential cuts is called the tread depth. Thus, preferably, the deepest cut in the axially central portion of the tread is a main circumferential cut.

[0026] A cutout or a portion of a cutout may be transverse or circumferential.

[0027] A cut or a cross-section is such that the cut extends along an average direction forming an angle strictly greater than 30°, preferably greater than or equal to 45°, with the circumferential direction of the tire, i.e., forming an angle less than or equal to 60°, preferably strictly less than 45°, with the axial direction of the tire. A cut or a cross-section may be continuous, i.e., not interrupted by a tread block or another cut, so that the two principal lateral faces determining its length are uninterrupted along the length of the cross-section or cross-section.A cut or a cross-section may also be discontinuous, that is, interrupted by one or more blocks of sculpture and / or one or more cutouts so that the two main lateral faces determining its length are interrupted by one or more blocks of sculpture and / or one or more cutouts.

[0028] A cut or circumferential portion is such that the cut or portion extends along an average direction forming an angle less than or equal to 30°, preferably less than or equal to 10°, with the circumferential direction of the tire, i.e., forming an angle strictly greater than 60°, preferably strictly greater than 80°, with the axial direction of the tire. In the case of a continuous circumferential cut, the two ends coincide and are joined by a curve making a complete turn of the tire. A cut or circumferential portion may be continuous, i.e., not interrupted by a tread block or another cut, so that the two principal lateral faces determining its length are uninterrupted over the entire circumference of the tire.A circumferential cut can also be discontinuous, that is, interrupted by one or more tread blocks and / or one or more cuts so that the two main lateral faces determining its length are interrupted by one or more tread blocks and / or one or more cuts over the whole of one revolution of the tire.

[0029] The tire according to the invention has a substantially toroidal shape around an axis of revolution substantially coinciding with the axis of rotation of the tire. This axis of revolution defines three directions conventionally used by those skilled in the art: an axial direction, a circumferential direction, and a radial direction.

[0030] By axial direction, we mean the direction substantially parallel to the axis of revolution of the tire, that is to say the axis of rotation of the tire.

[0031] By circumferential direction, we mean the direction which is substantially perpendicular to both the axial direction and to a radius of the tire (in other words, tangent to a circle whose center is on the axis of rotation of the tire).

[0032] By radial direction, we mean the direction along a radius of the tire, that is to say any direction intersecting the axis of rotation of the tire and substantially perpendicular to this axis.

[0033] By median plane of the tire (denoted M), we mean the plane perpendicular to the axis of rotation of the tire which is located at mid-axial distance of the two ribs and passes through the axial midpoint of the apex reinforcement.

[0034] By circumferential equatorial plane of the tire, in a meridional cutting plane, is meant the plane passing through the equator of the tire, perpendicular to the median plane and to the radial direction. The equator of the tire is, in a meridional cutting plane (plane perpendicular to the circumferential direction and parallel to the radial and axial directions), the axis parallel to the axis of rotation of the tire and located equidistant between the outermost radial point of the tread intended to be in contact with the ground and the innermost radial point of the tire intended to be in contact with a support, for example a rim.

[0035] By meridian plane, we mean a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0036] By radially inside, and radially outside respectively, we mean closer to the axis of rotation of the tire, and further from the axis of rotation of the tire respectively. By axially inside, and axially outside respectively, we mean closer to the median plane of the tire, and further from the median plane of the tire respectively.

[0037] By bead, we mean the portion of the tire designed to allow the tire to be attached to a mounting support, for example a wheel including a rim. Thus, each bead is specifically designed to be in contact with a hook on the rim allowing it to be attached.

[0038] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (i.e. bounds a and b excluded) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (i.e. including the strict bounds a and b).

[0039] Any angle made between two directions is the smallest of the angles made by these two directions with each other.

[0040] In preferred embodiments of the invention, the tires are intended for passenger vehicles as defined in the standard of the European Tyre and Rim Technical Organisation or "ETRTO", 2023. Such a tyre has a cross-section in a meridional plane characterized by a section height H and a nominal section width or bead size S as defined by the European Tyre and Rim Technical Organisation or "ETRTO", 2023 standard, such that the H / S ratio, expressed as a percentage, is at most 90 and at least 20, and the nominal section width S is at least 115 mm and at most 385 mm. Furthermore, the hook diameter D, defining the diameter of the tyre mounting rim, is at least 12 inches and at most 30 inches.

[0041] In preferred embodiments of the invention, the tires are so-called summer tires. By summer, we mean tires that are neither so-called 4-season or all-season tires, nor so-called winter tires.

[0042] Winter tires are identified by an M+S marking (M+S being the acronym for "Mud + Snow") and / or 3PMSF (3PMSF being the acronym for "3 Peak Mountain Snow Flake"). All-season tires, due to their performance on snow, also display the M+S and / or 3PMSF markings. Thus, a summer tire does not bear an M+S or 3PMSF marking.

[0043] In advantageous and optional embodiments, the wearing course comprises first and second axially lateral portions of the wearing course arranged axially outside and on either side of the axially central portion of the wearing course, each first and second axially lateral portion of the wearing course comprising respectively a first and second lateral material having respectively a dynamic shear modulus G*1, G*2 such that G*1 <G*C et G*2<G*C, le module dynamique en cisaillement G*2 étant mesuré à 23°C à 10% de déformation et à une fréquence de 10 Hz selon la norme ASTM D 5992 - 96, chaque première et deuxième portion axialement latérale de la couche de roulement étant au moins en partie agencée respectivement dans chaque première et deuxième portion axialement latérale de la bande de roulement.

[0044] Thus, the technical effect of the invention can be obtained on each first and second axially lateral portion of the wearing course.

[0045] In some embodiments, the first lateral material is identical to the second lateral material, and in particular G*1=G*2. In other embodiments, the first and second lateral materials are different, and in particular G*1>G*2 or G*1 <G*2.

[0046] In advantageous and optional embodiments, Elm < 1.80 mm, preferably Elm < 1.50 mm, more preferably Elm < 1.40 mm and even more preferably Elm < 1.20 mm.

[0047] By further reducing the value of the average radial distance Elm, the tread is made more rigid overall and the overall wear rate of the tire is reduced.

[0048] In advantageous and optional embodiments: - in the case where the tire includes an axially lateral portion of the tread layer, G*1 / G*C < 85%, preferably G*1 / G*C < 80%, - in the case where the tire includes first and second axially lateral portions of the tread layer, G*1 / G*C <85% and / or G*2 / G*C < 85%, preferably G*1 / G*C < 80% and / or G*2 / G*C < 80%.

[0049] The difference in intrinsic stiffness between the central material and the lateral material, or between each first and second lateral material, is increased. This further reduces the rolling resistance of the tire while still benefiting from the effect of the invention.

[0050] In advantageous and optional embodiments: - in the case where the tire includes an axially lateral portion of the tread layer, G*1 / G*C > 40%, - in the case where the tire includes first and second axially lateral portions of the tread layer, G*1 / G*C > 40% and / or G*2 / G*C > 40%.

[0051] By differentiating too much the intrinsic stiffness of the central material and the lateral material or of each first and second lateral material, there is a risk of promoting or decisively the wear of the central portion.

[0052] In an embodiment that reduces the rolling resistance of the tire: - in the case where the tire includes an axially lateral portion of the tread layer, 40% <G*1 / G*C < 70%, de préférence 40% <G*1 / G*C < 60%, - dans le cas où le pneumatique comprend des première et deuxième portions axialement latérales de la couche de roulement, 40% <G*1 / G*C < 70% et / ou 40% < G*2 / G*C < 70%, de préférence 40% <G*1 / G*C < 60% et 40% < G*2 / G*C < 60%.

[0053] Dans une première variante de ce mode de réalisation permettant de réduire la résistance au roulement tout en ménageant la rigidité de dérive : - in the case where the tire includes an axially lateral portion of the tread, the lateral material has a maximum dynamic loss tanDMAX23-l such that tanDMAX23-l < 0.20, preferably tanDMAX23-l <0.15 and the central material has a maximum dynamic loss tanDMAX23-0 such that 0.40 < tanDMAX23-0 < 0.50. - in the case where the tire comprises first and second axially lateral portions of the tread layer, each first and second material lateral exhibits respectively a maximum dynamic loss tanDMAX23-l, tanDMAX23-2, such that tanDMAX23-l < 0.20 and / or tanDMAX23-2 < 0.20, preferably tanDMAX23-l <0.15 and / or tanDMAX23-2 < 0.15 and the central material exhibits a maximum dynamic loss tanDMAX23-0 such that 0.40 < tanDMAX23-0 < 0.50.

[0054] In a second variant of this embodiment allowing for the maximization of the reduction in rolling resistance: - in the case where the tire includes an axially lateral portion of the tread, the lateral material has a maximum dynamic loss tanDMAX23-l such that tanDMAX23-l < 0.20, preferably tanDMAX23-l < 0.15 and the central material has a maximum dynamic loss tanDMAX23-0 such that tanDMAX23-0 < 0.40, preferably tanDMAX23-0 < 0.35, - in the case where the tire includes first and second axially lateral portions of the tread, each first and second lateral material has respectively a maximum dynamic loss tanDMAX23-l, tanDMAX23-2, such that tanDMAX23-l < 0.20 and / or tanDMAX23-2 < 0.20, preferably tanDMAX23-l <0.15 and / or tanDMAX23-2 < 0.15 and the central material has a maximum dynamic loss tanDMAX23-0 such that tanDMAX23-0 < 0.40, preferably tanDMAX23-0 < 0.35.

[0055] In an embodiment allowing the drift rigidity of the tire to be increased and thus improving its behavior: - in the case where the tire includes an axially lateral portion of the tread layer, 50% < G*1 / G*C < 85%, preferably 65% ​​< G*1 / G*C < 85% and more preferably 70% < G*1 / G*C < 85%. Even more preferably, 50% < G*1 / G*C < 80%, preferably 65% ​​< G*1 / G*C < 80% and more preferably 70% < G*1 / G*C < 80%, - in the case where the tire includes first and second axially lateral portions of the tread layer, 50% < G*1 / G*C < 85% and / or 50% < G*2 / G*C < 85%, preferably 65% ​​< G*1 / G*C < 85% and 65% < G*2 / G*C < 85% and more preferably 70% < G*1 / G*C < 85% and 70% < G*2 / G*C < 85%. Even more preferably, 50% < G*1 / G*C < 80% and / or 50% < G*2 / G*C < 80%, preferably 65% ​​< G*1 / G*C < 80% and 65% < G*2 / G*C < 80% and more preferably 70% < G*1 / G*C < 80% and 70% < G*2 / G*C < 80%.

[0056] In this embodiment allowing for increased fin rigidity, fin rigidity is favored at the expense of rolling resistance in a variant in which: - In the case where the tire includes an axially lateral portion of the tread layer, the lateral material exhibits a maximum dynamic loss tanDMAX23-l such that 0.30 < tanDMAX23-l and the central material has a maximum dynamic loss tanDMAX23-0 such that 0.50 < tanDMAX23-0, - in the case where the tire includes first and second axially lateral portions of the tread, each first and second lateral material has respectively a maximum dynamic loss tanDMAX23-l, tanDMAX23-2, such that 0.30 < tanDMAX23-l and / or 0.30 < tanDMAX23-2 and the central material has a maximum dynamic loss tanDMAX23-0 such that 0.50 < tanDMAX23-0.

[0057] Each dynamic loss tanDMAX23 is yet another dynamic property well known to those skilled in the art and is measured on the same Metravib VA4000 or DMA+450 type viscoanalyzer using specimens comprising a baked composition extracted from the tire. The response of the specimens subjected to a sinusoidal alternating simple shear load at a frequency of 10 Hz is recorded under determined temperature conditions (here 23°C) according to ASTM DI349-99. A strain amplitude sweep is performed from 0.1% cc to 100% cc (forward cycle), then from 100% cc to 0.1% cc (reverse cycle), cc meaning peak-to-peak. The specimen is of cylindrical cross-section as described in ASTM D 5992-96 (version reapproved in 2011, originally approved in 1996) in Figure X2.1 (circular embodiment) and has a diameter of 10 mm [0 to +0.04 mm] and a thickness of 2 mm [1.83-2.33].The tangent tanD of the phase angle D between the force exerted on the sample and its displacement represents a dynamic loss and is equal to the ratio G” / G’. The maximum value tanDMAX of the tangent tanD of the phase angle D observed on the deformation return cycle is recorded.

[0058] In preferred embodiments, the carving height belongs to a range from 5.0 mm to 10.0 mm, preferably from 6.0 mm to 8.0 mm.

[0059] In embodiments in which the main circumferential cutouts are relatively deep, each main circumferential cutout has a depth ranging from 4.0 mm to the carving height, preferably ranging from 5.0 mm to the carving height and more preferably ranging from 5.5 mm to the carving height.

[0060] In embodiments in which the main circumferential cutouts are relatively deep, each main circumferential cutout has a depth greater than or equal to 75% of the sculpture height, preferably 90% of the sculpture height.

[0061] In embodiments in which the main circumferential cutouts are relatively wide main circumferential grooves, each main circumferential cutout has a minimum width greater than or equal to 3.0 mm, preferably greater than or equal to 5.0 mm and more preferably ranging from 5.0 mm to 20.0 mm.

[0062] In advantageous and optional embodiments: - in the case where the tire includes an axially lateral portion of the tread, the axially central portion of the tread is in contact with the axially lateral portion of the tread via an interface arranged in the axially central portion of the tread or in the axially lateral portion of the tread, - in the case where the tire includes first and second axially lateral portions of the tread, the axially central portion of the tread is in contact with each first and second axially lateral portion of the tread respectively through a first and a second interface arranged respectively in each first and second axially lateral portion of the tread.

[0063] Where the tire includes an axially lateral portion of the tread, the arrangement of the interface in the axially central portion of the tread allows for a more distinct functionalization of the side of the tire carrying the axially lateral portion of the tread compared to the other side carrying the axially central portion. To this end, preferably, the axially lateral portion of the tread is arranged on the same side of the tire's median plane as the outer side of the tire, and the axially central portion is arranged on the same side of the tire's median plane as the inner side of the tire. By inner and outer sides, it is understood that the tire is designed so that one of its sides is arranged on the inner side and the other on the outer side.This orientation, specified by the tire manufacturer, ensures that the tire performs as intended. Indeed, mounting a tire with a different orientation than that specified by the manufacturer can lead to suboptimal vehicle handling. The outer side refers to the side of the tire that is fully visible from outside the vehicle when the tire is mounted. The inner side refers to the side of the tire that faces the wheel well of the vehicle on which it is mounted. Generally, the tire has markings indicating the inner and outer sides.

[0064] Still in the case where the tire includes an axially lateral portion of the tread, if we want to functionalize less distinctly the side of the tire carrying the axially lateral portion, the interface is arranged in the axially lateral portion of the tread.

[0065] In the case where the tire comprises first and second axially lateral portions of the tread layer, the compromise between Reduction in rolling resistance, drift stiffness, and wet grip. Indeed, an excessive proportion of lateral material, or of the first and second lateral materials, leads to a decrease in drift stiffness and wet grip. Conversely, an excessive proportion of the central material reduces the rolling resistance gain.

[0066] Optionally: - in the case where the tire includes an axially lateral portion of the tread, the axially central portion of the tread extends axially from a first axial edge of the tread surface arranged on the opposite side with respect to the median plane of the axially lateral portion to the interface, - in the case where the tire includes first and second axially lateral portions of the tread, the axially central portion of the tread extends axially from the first interface to the second interface.

[0067] Optionally: - in the case where the tire includes an axially lateral portion of the tread, the axially lateral portion extends axially from a second axial edge of the tread surface arranged on the same side of the median plane as the axially lateral portion of the tread to the interface, - in the case where the tire includes first and second axially lateral portions of the tread, the first axially lateral portion of the tread extends axially from a first axial edge of the tread surface arranged on the same side of the median plane as the first axially lateral portion of the tread to the first interface and the second axially lateral portion of the tread extends axially from a second axial edge of the tread surface arranged on the same side of the median plane as the second axially lateral portion of the tread to the second interface.

[0068] The invention is particularly advantageous in advantageous and optional embodiments in which: - in the case where the tire includes an axially lateral portion of the tread, the average thickness of the axially central portion of the tread is strictly greater than the average thickness of the axially lateral portion of the tread, - in the case where the tire comprises first and second axially lateral portions of the tread layer, the average thickness of the axially central portion of the tread layer is strictly greater than the average thickness of each first and second axially lateral portion of the layer bearing.

[0069] The determination of average thicknesses is carried out over the axial width of the running surface by measuring several thicknesses axially distributed across the axial width of the running surface. For example, a thickness will be measured every centimeter along the axial direction, starting from the first and second axial edges of the running surface. A running surface thickness is measured as the distance between a radially internal point of the running surface and its projection onto the running surface. A radially internal point is, in the case where the running surface is in direct contact with the top reinforcement, a point on the interface between the running surface and the top reinforcement.An internal radial point is, in the case where one or more layers are radially arranged between the tread and the crown reinforcement, a point on the interface between the innermost radial tread layer and the layer radially adjacent to this innermost radial tread layer. These measurements will be taken in several meridian planes equally distributed around the circumference of the tire, for example, in four meridian planes. The radial distances thus measured will then be averaged to obtain the average radial thickness.

[0070] In advantageous and optional first embodiments in which the tread comprises a radially inner layer arranged radially within the wearing course and distinct from the wearing course, the radially inner layer is arranged radially within: - the axially lateral portion of the tread layer in the case where the tire includes an axially lateral portion of the tread layer, or of each first and second axially lateral portion of the tread layer in the case where the tire includes first and second axially lateral portions of the tread layer, and - the axially central portion of the wearing course.

[0071] The radially inner layer optimizes certain tire performance characteristics, such as rolling resistance, wet grip, and handling. Therefore, the term "distinct from the tread layer" means that the radially inner layer is formed from one or more materials different from the lateral material or the first and second lateral materials.

[0072] In a first configuration of these initial variants, the radially inner layer may be designed not to come into contact with the ground during tire rolling, at least until a regulatory wear threshold is reached. This radially inner layer will be referred to as the support layer. However, at specific points, i.e., over an axial length less than 10% of the axial length The inner radial layer may come into contact with the ground, particularly due to the relative control of industrial processes. Preferably, the inner radial layer is in contact with a crown reinforcement of the tire, for example as described below.

[0073] In a second configuration of these first variants, the radially inner layer may be designed to come into contact with the ground during tire rolling before the tire reaches the regulatory wear threshold. The radially inner layer will be referred to as the worn tread layer, as opposed to the new tread layer, which is the outermost radially layer and is designed to be in contact with the ground when the tire is new.

[0074] In advantageous and optional second variants, the tread comprises at least one radially inner layer, the or each radially inner layer is formed in the lateral material in the case where the tire includes an axially lateral portion of the tread or in the first and / or in the second lateral material of the tread in the case where the tire includes first and second axially lateral portions of the tread, the radially inner layer being arranged radially inside the axially central portion of the tread.

[0075] Thus, compared to the first variants, the number of tread materials is reduced. Preferably, the first lateral material is identical to the second lateral material.

[0076] In other variants, the tread does not include an inner radial layer. Thus, the tread layer is in direct contact with the crown reinforcement of the tire, for example as described below.

[0077] Conventionally, the tire comprises a crown, two sidewalls, and two bead ribs, each sidewall connecting each bead to the crown. The tire also comprises a carcass reinforcement anchored in each bead and extending radially in each sidewall and axially in the crown, radially internal to the crown reinforcement.

[0078] In embodiments enabling the performance of so-called radial tires, for example as defined by the ETRTO, the carcass reinforcement comprises at least one carcass layer, the layer or each carcass layer comprising wire carcass reinforcement elements, each wire carcass reinforcement element extending substantially along a principal direction forming with the circumferential direction of the tire an angle, in absolute value, ranging from 80° to 90°. Alternatively, a variable angle ranging from 80° to 90° may be had in at least a portion of the sidewall and strictly less than 80° in the less a part of the top as described for example in US20190152262.

[0079] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which: - Figure [1] is a view, in a meridian cross-section, of a tire according to a first embodiment of the invention, - [Fig.2] is a detailed view of an axially central part of the top of the tire in [Fig.1], - [Fig.3] is a top view of the tread of the tire in [Fig.1], - Figure 4 is a detailed view of the tire tread in Figures 1 to 3, illustrating some cross-sections. - [Fig. 5] is a detailed view of the tire tread in Figures 1 to 3, illustrating other cross-sections, - Figures 6 and 7 are views similar to that of [Fig. 1] of tires according to the second and third embodiments of the invention, and - Figures 8, 9 and 10 are views similar to those of figures 3, 4 and 5 respectively of a tire according to a fourth embodiment of the invention.

[0080] In the figures relating to the tire, a reference frame X, Y, Z has been represented corresponding to the usual directions respectively axial (Y), radial (Z) and circumferential (X) of a tire.

[0081] Figures 5 show a tire according to the invention and designated by the general reference numeral 10. The tire 10 has a substantially toroidal shape about an axis of revolution substantially parallel to the axial direction Y. The tire 10 is intended for a passenger vehicle and has dimensions 255 / 40 R20. In the various figures, the tire 10 is shown in its new condition, i.e., having not yet been driven on. The tire 10 has an inner side INT and an outer side EXT.

[0082] The tire 10 includes a crown 12 comprising a tread 14 carrying a rolling surface 16 intended to come into contact with a ground during the rolling of the tire 10. The rolling surface 16 is axially delimited by first and second axial edges 18, 20. The tread 14 and the rolling surface 16 have an axial width LSR measured as the axial distance from the first axial edge 18 to the second axial edge 20.

[0083] The tread 14 comprises an axially central portion POb of the tread 14 and the first and second axially lateral portions Pib, P2b of the tread 14 arranged axially outside the axially central portion POb on either side of the axially central portion POb of the tread 14.

[0084] The tread 14 comprises several main circumferential cutouts, here four main circumferential grooves, comprising first, second, third and fourth main circumferential cutouts respectively designated by references 22, 24, 26, 28. The first and second main circumferential cutouts 22, 24 are arranged axially on either side of the median plane M of the tire 10 and are the outermost axially main circumferential cutouts of the tread 14 and below referred to as the outermost axially main circumferential cutouts 22, 24.

[0085] The first axially lateral portion Pib and the second axially lateral portion P2b are arranged axially outside the first axially external main circumferential cutout 22 and the second axially external main circumferential cutout 24, respectively. The first axially lateral portion Pib extends axially from the first axial edge 18 of the rolling surface 16 to the axially external edge 19 of the first axially external main circumferential cutout 22. The second axially lateral portion P2b extends axially from the second axial edge 20 of the rolling surface 16 to the axially external edge 21 of the second axially external main circumferential cutout 24.The axially central portion POb of the tread 14 extends axially from the first axially lateral portion Pib of the tread 14 to the second axially lateral portion P2b of the tread 14.

[0086] As illustrated in [Fig. 2], each main circumferential cutout 22 to 28 has a depth Hr ranging from 4.0 mm to the carving height Hs, preferably from 5.0 mm to the carving height Hs, and more preferably from 5.5 mm to the carving height Hs. Each depth Hr is greater than or equal to 50%, preferably 75%, and more preferably 90% of the carving height Hs. Here, Hs=6.5 mm, Hr=6.0 mm for each first and second main axially external circumferential cutout 22, 24 and Hs=Hr=6.5 mm for each main circumferential cutout 26, 28. Each main circumferential cutout 22 to 28 has respectively a minimum width greater than or equal to 3.0 mm, preferably greater than or equal to 5.0 mm and more preferably ranging from 5.0 mm to 20.0 mm.

[0087] The axially central portion POb comprises central ribs, here referred to as first, second, and third central ribs, respectively designated by reference numerals 32, 34, and 36. Each central rib 32, 34, and 36 is arranged axially between two of the adjacent main circumferential cutouts 22 to 28. Each central rib 32, 34, and 36 comprises transverse cutouts 38, 38', 40, 40', and 42. provided in the central ribs 32, 34, 36.

[0088] Each transverse cutout 38, 38', 40, 40', 42 extends between its first and second ends along an average direction forming an angle respectively noted A38, A38', A40, A40', A42 with the axial direction Y of the tire 10 such that A38=A38'=A40=A40'=A42=10°.

[0089] With reference to Figures 3 to 5, each transverse cut 38 comprises two portions 381, 382 having depths H81, H82 respectively such that H81 = 4.9 mm and H82 = 1.4 mm. Each transverse cut 38' comprises a portion 381' having a depth H81' = 4.9 mm. Each transverse cut 40 comprises two portions 401, 402 having depths H01, H02 respectively such that H01 = 1.4 mm and H02 = 4.9 mm. Each transverse cut 40' comprises a portion 402' having a depth H02' = 4.9 mm. Each transverse cut 42 comprises two portions 421, 422 having depths H21, H22 respectively such that H21 = 1.4 mm and H22 = 4.9 mm. Each portion 381, 382, ​​381', 401, 402, 402', 421, 422 has a minimum width less than or equal to 1.5 mm, preferably ranging from 0.2 mm to 1.5 mm and here equal to 0.4 mm.

[0090] Each first and second axially lateral portion Pib, P2b comprises respectively a first and a second lateral rib respectively designated by reference numerals 44, 46. The tread 14 comprises first and second transverse cutouts 48', 48”, 50', 50” formed at least partially in each first and second axially lateral portion Pib, P2b. The first transverse cutouts 48', 48” are arranged on the inner side INT of the tire 10. The second transverse cutouts 50', 50” are arranged on the outer side EXT of the tire 10.

[0091] Each first transverse cut 48' extends along a mean direction forming an angle A48' of 10° with the axial direction Y and includes a portion 481' having a maximum depth H481' = 4.7 mm. Each first transverse cut 48' also includes a portion axially enlarged outside the portion formed in the first axially lateral portion Pib and having a width of 4.0 mm. Each first transverse cut 48" extends along a mean direction forming an angle A48" ​​of 10° with the axial direction Y and includes two portions 481" and 482" having maximum depths H481" = 4.7 mm and H482" = 1.4 mm, respectively.

[0092] Each second transverse cut 50', 50" extends along a mean direction forming an angle A50', A50" equal to 0° with the axial direction Y and includes a portion 501', 501" having a depth H501', H501" equal to 4.7 mm. Each second transverse cut 50', 50" also includes a portion 502', 502" having a depth H502', H502" equal to 1.4 mm. Each second transverse cut 50' also includes an axially enlarged portion outside the portion formed in the second axially lateral portion P2b and having a width equal to 3.0 mm.

[0093] Each first and second transverse cutout 48', 48" has a minimum width less than or equal to 1.5 mm, preferably ranging from 0.2 mm to 1.5 mm and here equal to 0.4 mm. Each first and second transverse cutout 50', 50" has a minimum width greater than or equal to 1.5 mm, preferably ranging from 1.5 mm to 6.0 mm and here equal to 4.5 mm.

[0094] All the transverse cutouts described above, inclined or not, are provided with chamfers which are not shown.

[0095] Due to the presence of the various transverse cutouts described above, the tread 14 has a volumetric notch ratio of 25%, which gives it a good compromise between the external noise generated by the tire and the grip on wet ground.

[0096] The tread 14 comprises a tread layer 52 and a radially inner layer 54 arranged radially inside the tread layer 52 and distinct from the tread layer 52.

[0097] The wearing course 52 comprises an axially central portion POc of the wearing course 52 and the first and second axially lateral portions Pic, P2c of the wearing course 52 arranged axially outside and on either side of the axially central portion POc of the wearing course 52. The axially central portion POc of the wearing course 52 is at least partly arranged in the axially central portion POb of the tread 14. Each first and second axially lateral portion Pic, P2c of the wearing course 52 is at least partly arranged respectively in each first and second axially lateral portion Pib, P2b of the tread 14.

[0098] The radially inner layer 54 is arranged radially inside each first and second axially lateral portion Pic, P2c of the wearing course 52 and of the axially central portion POc of the wearing course 52. The axially central portion POc of the wearing course 52 includes the median plane M.

[0099] The axially central portion POc is in contact with each first and second axially lateral portion Pic, P2c respectively via a first and second interface 56, 58 arranged respectively in each first and second axially lateral portion Pib, P2b of the tread 14.

[0100] The axially central portion POc of the wearing course 52 extends axially from the first interface 56 to the second interface 58. The first axially lateral portion Pic of the wearing course 54 extends axially from the first axial edge 18 to the first interface 56 arranged on the same side of the plane median M than the first axially lateral portion Pic of the wearing course 52. The second axially lateral portion P2c extends axially from the second axial edge 20 arranged on the same side of the median plane M as the second axially lateral portion P2c of the wearing course 52 to the second interface 58.

[0101] The axially central portion POc has an axial width strictly greater than the axial width of each first and second axially lateral portion Pic, P2c.

[0102] The average thickness EOcm of the thicknesses EOc of the axially central portion POc is strictly greater than the average thickness Elcm, E2cm of the thicknesses Elc, E2c respectively of each first and second axially lateral portion Pic, P2c as can be seen in figures 1 and 2.

[0103] The axially central portion POc comprises a central material MO having a shear dynamic modulus G*C measured at 23°C at 10% strain and at a frequency of 10 Hz according to ASTM D 5992-96. Each first and second axially lateral portion Pic, P2c comprises a first and second lateral material Ml, M2 respectively having a shear dynamic modulus G*l, G*2 measured at 23°C at 10% strain and at a frequency of 10 Hz according to ASTM D 5992-96. In the embodiment described here, rolling resistance is prioritized over drift stiffness. The first and second lateral materials Ml, M2 are identical here.

[0104] The dynamic shear moduli G*C, G*1, G*2 satisfy G*1 <G*C et G*2<G*C. En outre, G*1 / G*C < 85% et G*2 / G*C < 85%, de préférence G*1 / G*C < 80% et G*2 / G*C < 80%. Également, G*1 / G*C >40% and G*2 / G*C > 40%. Here, 40% <G*1 / G*C < 70% et / ou 40% < G*2 / G*C < 70%, de préférence 40% <G*1 / G*C < 60% et 40% < G*2 / G*C < 60%. Dans ce mode de réalisation, G*1=G*2=1,35 MPa, G*C=2,66 MPa et G*1 / G*C=G*2 / G*C=51 %. La dureté shore de chaque premier et deuxième matériau latéral Ml, M2 est égal à 53 et la dureté shore du matériau central MO est égal 67. La dureté shore est par exemple mesurée selon la norme JIS K6253 à 23°C en utilisant un duromètre de type A.The dynamic shear modulus G*'1, G*'2 of each first and second lateral material M1, M2 measured not at 10% strain and at an imposed temperature of 23°C but at 60°C and an imposed stress (0.7 MPa) is equal to 0.95 MPa and the dynamic shear modulus G*'0 of the central material MO measured not at 10% strain and at an imposed temperature of 23°C but at 60°C and an imposed stress (0.7 MPa) is equal to 1.14 MPa.

[0105] The complex shear modulus G*' under imposed stress is determined using a Metravib VA4000 or DMA+450 type viscoanalyzer with test specimens comprising a baked composition extracted from the tire. The response of specimens subjected to sinusoidal loading in alternating simple shear, at a frequency of 10 Hz under a force equal to 55 N. A temperature sweep is performed between -80°C and 80°C at a rate of 1.5°C / min after the specimens have been previously accommodated to 100% peak-to-peak strain at a temperature less than or equal to 40°C, for example 23°C. The specimen has a cylindrical cross-section as described in ASTM D 5992-96 (version reapproved in 2011, originally approved in 1996) in Figure X2.1 (circular embodiment) and has a diameter of 10 mm [0 to +0.04 mm] and a thickness of 2 mm [1.83-2.33]. Note that a force of 55 N, in the case of a specimen with a diameter of 10.00 mm, is equivalent to a peak-to-peak stress of 0.7 MPa. The complex shear modulus G*' is measured at 60°C.

[0106] Each first and second lateral material M1, M2 respectively has a maximum dynamic loss tanDMAX23-1, tanDMAX23-2, such that tanDMAX23-1 < 0.20 and tanDMAX23-2 < 0.20, preferably tanDMAX23-1 < 0.15 and tanDMAX23-2 < 0.15 and the central material MO has a maximum dynamic loss tanDMAX23-0 such that 0.40 < tanDMAX23-0 < 0.50. Here, tanDMAX23-1=tanDMAX23-2=0.14 and tanDMAX23-0=0.46.

[0107] The glass transition temperature Tg of each first and second lateral material M1, M2 is -24°C and the glass transition temperature Tg of the central material MO is -10°C. Each glass transition temperature Tg is determined using a Metravib VA4000 or DMA+450 viscoanalyzer with test specimens containing a baked composition extracted from the tire. The response of the specimens subjected to sinusoidal alternating simple shear loading at a frequency of 10 Hz under a force of 55 N is recorded. A temperature sweep is performed between -80°C and 80°C at a rate of 1.5°C / min. The test specimen has a cylindrical cross-section as described in ASTM D 5992-96 (version reapproved in 2011, originally approved in 1996) in Figure X2.1 (circular embodiment) and has a diameter of 10 mm [0 to +0.04 mm] and a thickness of 2 mm [1.83-2.33].It should be noted that a force of 55 N, in the case of a specimen with a diameter of 10.00 mm, is equivalent to a stress with a peak-to-peak magnitude of 0.7 MPa. The glass transition temperature Tg is taken to be the temperature at which the tangent of the phase angle tanD is maximum. The tangent tanD of the phase angle D between the force exerted on the sample and its displacement represents a dynamic loss and is equal to the ratio G” / G’.

[0108] Table 1 below shows the compositions from which the first and second lateral materials M1 and M2, and the central material MO, were manufactured in a conventional manner known to those skilled in the art. The values ​​are data in pce.

[0109] [Tables] Composition M1,M2 MO SBR 1 (1) 0 0 SBR 2 (2) 0 37 SBR 3 (3) 100 63 SBR 4 (4) 0 0 Carbon black (5) 3 6 Silica (6) 60 132 Silane (7) 0 12 Silane (8) 6 0 Resin (9) 43 76 Other additives (10) 18 33

[0110] (1) - Styrene-Butadiene Elastomer described as polymer B on page 34 of WO2018115722; (2) - Styrene-Butadiene elastomer from Arlanxeo having a Mooney viscosity of 54 UM according to ASTM D 1646 (1+4 @ 100 °C), a vinyl unit content of 18%, an average styrene content of 27%, and a glass transition temperature of -48 °C; (3) - Styrene-Butadiene elastomer described as polymer C on page 34 of WO2018115722; (4) - Styrene-Butadiene elastomer described as control polymer A on page 39 of WO2022162292; (5) - Grade 234 carbon black according to ASTM D-1765; (6) - 160MP silica from Solvay; (7) - "Si75" from Evonik; (8) - "Si69" from Evonik; (9) - N-ter-butyl-2-benzothiazyl sulfenamide (marketed by Flexsys;(10) - The other additives are classically known to those skilled in the art and include here in particular a protective wax, Nl,3-dimethylbutyl-N-phenylparaphenylenediamine, N-cy-clohexyl-benzothiazyl sulfenamide, diphenylguanidine, sulfur, stearic acid, zinc oxide, high oleic sunflower oil and an AMO70 processing agent.

[0111] The radially inner layer 54 comprises a material MS having a dynamic shear modulus G*S measured at 23°C at 10% strain and at a frequency of 10 Hz according to ASTM D 5992-96 such that G*S = 1.67 MPa and a maximum dynamic loss tanDMAX23-S = 0.13. The material MS is made from a composition conventionally comprising at least one diene elastomer and here comprising a styrene-butadiene elastomer, a butadiene elastomer, and a ca natural rubber, at least one filler and including here a carbon black, for example a carbon black N234, and a silica, a coupling agent for example a silane “Si69” or “Si75” from the company Evonik, a resin, for example a hydrogenated DCPD resin marketed under the reference PR-383 by the company Exxon or a C5-C9 hydrocarbon cut marketed under the reference ECR-373 by the company Exxon, as well as various additives such as those described previously for materials MO, M1 and M2.

[0112] With reference to Figures 1 and 2, the apex 12 comprises an apex reinforcement 60 extending into the apex 12 in the circumferential direction X. The tire 10 also comprises a sealing layer 62 for an inflation gas intended to delimit an internal cavity closed with a mounting support for the tire 10 once the tire 10 is mounted on the mounting support, for example, a rim. The apex reinforcement 60 comprises a working reinforcement 64 and a shrink-fit reinforcement 66.

[0113] The working frame 64 comprises two working layers 68, 70. The radially outer working layer 70 is arranged radially outside the radially inner working layer 68.

[0114] The shrink-fitting armature 66 comprises at least one shrink-fitting layer and here comprises a shrink-fitting layer 72.

[0115] The top reinforcement 60 is arranged radially inside the tread 14. The shrink-fit reinforcement 66, here the shrink-fit layer 72, is arranged radially outside the working reinforcement 64 and radially inside the tread 14. The shrink-fit reinforcement 66 is therefore radially interposed between the working reinforcement 64 and the tread 14. The shrink-fit layer 72 is therefore the outermost radially outermost layer of the top reinforcement 60.

[0116] The tire 10 comprises two sidewalls 74 extending radially inwards from the apex 12. The tire 10 further comprises two ribs 76 radially inwards from the sidewalls 74. Each sidewall 74 connects each rib 76 to the apex 12.

[0117] The tire 10 comprises a carcass reinforcement 78 anchored in each bead 76, in this case is wound around two beads 80. The carcass reinforcement 78 extends radially in each sidewall 74 and axially in the crown 12 radially internally to the crown reinforcement 60. The crown reinforcement 60 is arranged radially between the tread 14 and the carcass reinforcement 78. The carcass frame 78 comprises at least one carcass layer and here comprises a single carcass layer 82.

[0118] With reference to [Fig.2], each working layer 68, 70, shrink-fit layer 72 and carcass layer 82 comprises a polymeric matrix, here an elastomeric matrix in which one or more wire reinforcement elements of the corresponding layer are embedded. Thus, each working layer 68, 70 comprises working wire reinforcement elements 680, 700 respectively, the shrink-fit layer 72 comprises shrink-fit wire reinforcement elements 720 and the carcass layer 82 comprises carcass wire reinforcement elements 820. The angles of the wire reinforcement elements as well as the materials of the wire reinforcement elements are described for example in WO2021250331.

[0119] The interfaces between two adjacent layers are represented by dashed lines. In [Fig. 2], the following are shown: - the surface 100 passing through the innermost radial point of the deepest cut in the axially central portion POb of the tread 14 and substantially parallel to the tread surface, here passing through the innermost point of the main circumferential cuts 26, 28 and substantially parallel to the tread surface 16, - the radially outer surface 102 passing through the radially outermost points of the most radially outer wire reinforcement elements 720 among the wire reinforcement elements 720 of the radially outermost layer 72 arranged vertically above the axially central portion POb of the tread 14.

[0120] In the axially central portion POb of the tread 14, the average radial distance Elm of the distances El between the surface 100 and the radially outer surface 102 is such that Elm < 2.00 mm, preferably Elm < 1.80 mm. Furthermore, Elm > 0.50 mm, preferably Elm > 1.00 mm. In this case, Elm = 1.70 mm. Alternatively, Elm < 1.50 mm could be considered, most preferably Elm < 1.40 mm, and even more preferably Elm < 1.20 mm.

[0121] We will now describe tires according to second, third and fourth embodiments with reference to figures 6 to 10. Elements analogous to those described with reference to the first embodiment are designated by identical references.

[0122] Unlike the tire according to the first embodiment, the tire according to the second embodiment of [Fig. 6] does not comprise a second axially lateral portion of the wearing course but an axially central portion POc of the wearing course 52 and an axially lateral portion Pic arranged axially outside the axially central portion POc. The axially central portion POc of the wearing course 52 extends axially from the first axial edge 18 of the tread surface 16 arranged on the opposite side with respect to the median plane M of the axially lateral portion Pic to a contact interface 57 between the axially central portion POc and the axially lateral portion Pic. The axially lateral portion Pic of the wearing course 52 extends axially from the second axial edge 20 of the rolling surface 16 arranged on the same side of the median plane M as the axially lateral portion Pic up to the interface 57. The axially lateral portion Pic comprises the first material Ml and the axially central portion POc comprises the material MO described previously.

[0123] Furthermore, the axially central portion POc is in contact with the axially lateral portion Pic via the interface 57 which is arranged in the axially central portion POb of the tread 14, and here in the central rib 36 which is the rib adjacent to the main axially external circumferential cutout 24 and arranged axially inside the main axially external circumferential cutout 24.

[0124] The axially lateral portion Pic is arranged on the same side of the median plane M as the outer side EXT of the tire 10 and the axially central portion POc is arranged on the same side of the median plane M as the inner side INT of the tire 10. The axially central portion POc has an axial width strictly greater than the axial width of the axially lateral portion Pic.

[0125] Unlike the tire according to the first embodiment, the tire according to the third embodiment of [Fig. 7] comprises a radially inner layer 54 formed in each first and second lateral material M1, M2 (the first and second lateral materials are identical). The radially inner layer 54 is formed in each first and second lateral material M1, M2 of the tread 52. The radially inner layer 54 is arranged radially within the axially central portion POc of the tread 52.

[0126] Unlike the tire according to the first embodiment, the tire 10 according to the fourth embodiment of figures 8 to 10 comprises a tread 14 in which each transverse cut 38, 38', 40, 40', 42 extends between its first and second ends in an average direction forming an angle respectively noted A38, A38', A40, A40', A42 with the axial direction Y of the tire 10 such that A38=A38'=10° and A40=A40'=A42=40°.

[0127] With reference to Figures 8 to 10, each transverse cut 38 comprises three portions 381, 382, ​​383 having depths H81, H82, H83 respectively, such that H82 = 4.7 mm and H81 = H83 = 1.4 mm. Each transverse cut 38' comprises two portions 381', 382' having depths H81' = 1.4 mm and H82' = 4.7 mm respectively. Each transverse cut 40 comprises two portions 401, 402 having depths H01, H02 respectively, such that H01 = 1.4 mm and H02 = 4.9 mm. Each transverse cut 40' comprises one portion 402' having a depth H02' = 4.9 mm. Each transverse cut 42 comprises two portions 421, 422 having depths H21, H22 respectively, such that H21=1.4 mm and H22=4.9 mm. Each portion 381, 382, ​​383, 381', 382', 401, 402, 402', 421, 422 has a minimum width less than or equal to 1.5 mm, preferably ranging from 0.2 mm to 1.5 mm and here equal to 0.4 mm.

[0128] Each first and second axially lateral portion Pib, P2b comprises respectively a first and a second lateral rib respectively designated by reference numerals 44, 46. The tread 14 comprises first and second transverse cutouts 48', 48”, 50', 50” formed at least partially in each first and second axially lateral portion Pib, P2b. The first transverse cutouts 48', 48” are arranged on the inner side INT of the tire 10. The second transverse cutouts 50', 50” are arranged on the outer side EXT of the tire 10.

[0129] Each first transverse cut 48' extends along a mean direction forming an angle A48' of 10° with the axial direction Y and includes a portion 481' having a maximum depth H481' = 4.7 mm. Each first transverse cut 48' also includes a portion axially enlarged outside the portion formed in the first axially lateral portion Pib and having a width of 4.0 mm. Each first transverse cut 48" extends along a mean direction forming an angle A48" ​​of 10° with the axial direction Y and includes two portions 481" and 482" having a maximum depth H481" = 4.7 mm and a maximum depth H482" = 1.4 mm, respectively.

[0130] Each second transverse cutout 50', 50" extends along a mean direction forming an angle A50', A50" of 10° with the axial direction Y and includes a portion 501', 501" having a depth H501', H501" of 4.7 mm. Each second transverse cutout 50', 50" also includes a portion 502', 502" having a depth H502', H502" of 1.4 mm. Each second transverse cutout 50' also includes a portion axially enlarged outside the portion formed in the second axially lateral portion P2b and having a width of 3.0 mm.

[0131] Each first and second transverse cutout 48', 48”, 50', 50” has a minimum width less than or equal to 1.5 mm, preferably ranging from 0.2 mm to 1.5 mm and here equal to 0.4 mm.

[0132] All the transverse cutouts described above, inclined or not, are provided with chamfers which are not shown.

[0133] Due to the presence of the various transverse cutouts described above, in particular due to the presence of the second transverse cutouts 50', 50" having widths smaller than those of the second transverse cutouts 50', 50" of the tire according to the first embodiment, the tread 14 has a volumetric notch ratio of 22%, which allows it to generate an external noise lower than that of the tire according to the first embodiment in exchange for slightly degraded grip on wet ground.

[0134] In a first material variant MO, M1, M2 of the tire according to the fourth embodiment, which promotes drift stiffness, the dynamic shear moduli G*C, G*1, G*2 satisfy 50% < G*1 / G*C < 85% and / or 50% < G*2 / G*C < 85%, preferably 65% ​​< G*1 / G*C < 85% and 65% < G*2 / G*C < 85%, and more preferably 70% < G*1 / G*C < 85% and 70% < G*2 / G*C < 85%, and even more preferably 50% < G*1 / G*C < 80% and / or 50% < G*2 / G*C < 80%, preferably 65% ​​< G*1 / G*C < 80% and 65% < G*2 / G*C < 80% and more preferably 70% < G*1 / G*C < 80% and 70% < G*2 / G*C < 80%. In this first embodiment of materials MO, M1 and M2, G*1=G*2=2.56 MPa, G*C=3.40 MPa and G*1 / G*C=G*2 / G*C=75%.

[0135] In this first embodiment of the materials MO, Ml and M2, the Shore hardness of each first and second lateral material Ml, M2 is equal to 66 and the Shore hardness of the central material MO is equal to 74. The dynamic shear modulus of each first and second lateral material Ml, M2 measured not at 23°C but at 60°C and under an imposed stress (0.7 MPa) is equal to 1.38 MPa and the dynamic shear modulus of the central material MO measured not at 23°C but at 60°C and under an imposed stress (0.7 MPa) is equal to 1.40 MPa.

[0136] In this first embodiment of the materials MO, Ml and M2, each first and second lateral material Ml, M2 respectively has a maximum dynamic loss tanDMAX23-l, tanDMAX23-2, such that 0.30 < tanDMAX23-l and 0.30 < tanDMAX23-2 and the central material MO has a maximum dynamic loss tanDMAX23-0 such that 0.50 < tanDMAX23-0 and here tanDMAX23-l=tanDMAX23-2=0.32 and tanDMAX23-0=0.54.

[0137] In this first embodiment of the materials MO, Ml and M2, the glass transition temperature Tg of each first and second lateral material Ml, M2 is equal to -10°C and the glass transition temperature Tg of the central material MO is equal to -4°C.

[0138] Table 2 below shows the compositions from which the first and second lateral materials M1 and M2, and the central material MO, of this first embodiment of materials MO, M1, and M2 described above, were manufactured in a conventional manner known to those skilled in the art. The values ​​are given in pieces. The constituents are identical to those in Table 1.

[0139] [Tables2] Composition M1,M2 MO SBR 1 (1) 100 35 SBR 2 (2) 0 0 SBR 3 (3) 0 0 SBR 4 (4) 0 65 Carbon black (5) 3 5 Silica (6) 98 134 Silane (7) 11 12 Silane (8) 0 0 Resin (9) 37 59 Other additives (10) 23 33

[0140] Still in this first embodiment of the materials MO, M1 and M2, the MS material of the radially inner layer 54 has a dynamic shear modulus G*S measured at 23°C at 10% strain and at a frequency of 10 Hz according to ASTM D 5992-96 such that G*S=1.88 MPa and a maximum dynamic loss tanDMAX23-S=0.12. The MS material is made from a composition as described above using N550 carbon black instead of N234 carbon black and the proportions of which a person skilled in the art will be able to modify in order to obtain the dynamic properties described above.

[0141] In a second material variant MO, M1, M2 of the tire according to the fourth embodiment allowing for the reduction of rolling resistance, the dynamic shear moduli G*C, G*1, G*2 satisfy 40% <G*1 / G*C < 70% et / ou 40% < G*2 / G*C < 70%, de préférence 40% <G*1 / G*C < 60% et 40% < G*2 / G*C < 60%. Dans cette deuxième variante de réalisation des matériaux MO, Ml et M2, G*1=G*2=1,35 MPa, G*C=2,56 MPa et G*1 / G*C=G*2 / G*C=53 %.

[0142] In this second embodiment of the materials MO, Ml and M2, the Shore hardness of each first and second lateral material Ml, M2 is equal to 53 and the Shore hardness of the central material MO is equal to 66. The dynamic shear modulus of each first and second lateral material Ml, M2 measured not at 23°C but at 60°C and under an imposed stress (0.7 MPa) is equal to 0.95 MPa and the dynamic shear modulus of the central material MO measured not at 23°C but at 60°C and under an imposed stress (0.7 MPa) is equal to 1.38 MPa.

[0143] In this second embodiment of the materials MO, M1 and M2, each The first and second lateral materials M1 and M2 respectively have a maximum dynamic loss tanDMAX23-1 and tanDMAX23-2 such that tanDMAX23-1 < 0.20 and tanDMAX23-2 < 0.20, preferably tanDMAX23-1 < 0.15 and tanDMAX23-2 < 0.15, and the central material MO has a maximum dynamic loss tanDMAX23-0 such that tanDMAX23-0 < 0.40. Here, tanDMAX23-1 = tanDMAX23-2 = 0.14 and tanDMAX23-0 = 0.32.

[0144] In this second embodiment of the materials MO, Ml and M2, the glass transition temperature Tg of each first and second lateral material Ml, M2 is equal to -24°C and the glass transition temperature Tg of the central material MO is equal to -10°C.

[0145] Still in this second embodiment of the materials MO, M1 and M2, the material MS of the radially inner layer 54 is identical to that of the tire according to the first embodiment.

[0146] Table 3 below shows the compositions from which the first and second lateral materials M1 and M2, and the central material MO, of this second embodiment of materials MO, M1, and M2 described above, were manufactured in a conventional manner known to those skilled in the art. The values ​​are given in pieces. The constituents are identical to those in Table 1.

[0147] [Tables3] Composition M1,M2 MO SBR 1 (1) 0 100 SBR 2 (2) 0 0 SBR 3 (3) 100 0 SBR 4 (4) 0 0 Carbon black (5) 3 3 Silica (6) 60 98 Silane (7) 0 11 Silane (8) 6 0 Resin (9) 43 37 Other additives (10) 18 23

[0148] COMPARATIVE TEST

[0149] The tire 10 according to the first embodiment was compared with a control tire T. Unlike the tire 10, the control tire T is such that Elm > 2.0 mm and such that G*l=G*2=l.70 MPa, G*C=2.69 MPa.

[0150] We ran 10 and T tires on the same vehicle each time Tesla Model Y in a predominantly rear-wheel drive mode. Tire wear on the rear tires was recorded over approximately 15,000 km. To shorten the test, wear was extrapolated until a portion of the tread reached the maximum wear indicated by a regulatory wear indicator.

[0151] The maximum mileage achieved by each tire (which reflects the tire's lifespan) and the tire's wear point, i.e., the point on the tread that reached maximum wear, were thus recorded. The results are summarized in Table 4 below, using tire T as the base 100.

[0152] [Tables4] T 10 Lifespan (base 100) 100 109 Death Point Portion P2c Rib 36

[0153] Unlike the control tire T, for which service life is determined by the early attainment of a regulatory wear indicator on one of the axially lateral portions, the service life of the tire 10 is determined by the later attainment of a regulatory wear indicator on the axially lateral portion and the earlier attainment of a regulatory wear indicator on the axially central portion. Furthermore, the service life of the tire 10 according to the invention is 9 points longer than that of the control tire.

[0154] Thus, the invention has made it possible, on the one hand, to delay the wear of the tread layer in each first and second axially lateral portion of the tread layer and, on the other hand, to extend the life of the tire.

[0155] The invention is not limited to the embodiments described above. Indeed, it will be possible, without any difficulty and depending on the performance compromise sought, to combine the treads of the tires according to each first, second, third embodiment with the first or second variant of the materials MO, M1 and M2 of the fourth embodiment described above.

[0156] It may also be provided that the tread includes noise reduction devices, in particular Helmoltz resonators as described for example in EP0989000, EP2011671, EP2240335, EP2627524.

[0157] It may also be provided that the tire includes a noise reduction device as described in WO2022 / 069822 or as described in EP1219944, EP1253025, EPI 184207, EPI 110763, EP1876038.

Claims

Demands

1. A tire (10) comprising a crown (12) comprising a tread (14) carrying a tread surface (16) and a crown reinforcement (60) arranged radially within the tread (14), the tread (14) comprising a tread layer (52) comprising an axially central portion (POc) of the tread layer (52) and an axially lateral portion (Pic, P2c; Pic) of the tread layer (52) arranged axially outside the axially central portion (POc) of the tread layer (52), the axially central portion (POc) and the axially lateral portion (Pic, P2c; Pic) of the tread layer (52) comprising respectively a central material (MO) and a lateral material (M1, M2) having respectively a dynamic shear modulus G*C, G*1 such that G*1 <G*C, chaque module dynamique en cisaillement G*C,G*1 being measured at 23°C at 10% deformation and at a frequency of 10 Hz according to ASTM D 5992-96, the tread comprising an axially central portion (POb) of the tread (14) and the first and second axially lateral portions (Pib, P2b) of the tread (14) arranged axially outside and on either side of the axially central portion (POb) of the tread, the tread (14) comprising principal circumferential cutouts (22, 24, 26, 28) having a depth greater than or equal to 50% of the tread height comprising first and second axially external principal circumferential cutouts (22, 24) arranged axially on either side of the median plane (M) of the tire (10), the first and second axially external principal circumferential cutouts (22,24) being the outermost axially main circumferential cutouts of the tread (14), each first and second axially lateral portion (Pib, P2b) of the tread (14) being arranged axially outside each first and second axially outer main circumferential cutout (22, 24) respectively and the axially central portion (POb) of the tread (14) extending from the first axially lateral portion (Pib) of the tread (14) to the second axially, lateral (P2b) of the tread (14), the axially central portion (POc) of the wearing course (52) being at least partly arranged in the axially central portion (POb) of the tread (14), the axially lateral portion (Pic, P2c; Pic) of the wearing course (52) being at least partly arranged in one of the first and second axially lateral portions (Pib, P2b) of the tread (14), the apex reinforcement (60) comprising a radially outermost layer (72) and comprising reinforcing elements (720) embedded in a polymer matrix, the average radial distance Elm in the axially central portion (POb) of the tread (14) between: - the surface (100) passing through the radially innermost point of the deepest cut (26, 28) formed in the axially central portion (POb) of the tread (14) and substantially parallel to the rolling surface (16),and - the radially outer surface (102) passing through the radially outermost points of the radially outermost reinforcing elements (720) among the reinforcing elements (720) of the radially outermost layer (72) arranged vertically above the axially central portion (POb) of the tread (14), is such that Elm < 2.00 mm.

2. A tire (10) according to the preceding claim, wherein the wearing course comprises first and second axially lateral portions (Pic, P2c) of the wearing course (52) arranged axially outside and on either side of the axially central portion (POc) of the wearing course (52), each first and second axially lateral portion (Pic, P2c; Pic) of the wearing course (52) comprising respectively a first and second lateral material (M1, M2) having respectively a dynamic shear modulus G1, G2 such that G1 <G*C et G*2<G*C, le module dynamique en cisaillement G*2 étant mesuré à 23 °C à 10% de déformation et à une fréquence de 10 Hz selon la norme ASTM D 5992 - 96, chaque première et deuxième portion axialement latérale (Pic, P2c ; Pic) de la couche de roulement (52) étant au moins en partie agencée respectivement dans chaque première et deuxième portion axialement lateral (Pib, P2b) of the tread (14).

3. Pneumatic (10) according to any one of the preceding claims, wherein Elm < 1.80 mm, preferably Elm < 1.50 mm, more preferably Elm < 1.40 mm and even more preferably Elm < 1.20 mm.

4. Tire (10) according to any one of the preceding claims, wherein: - in the case where the tire (10) comprises an axially lateral portion (Pic) of the tread (52), G*1 / G*C < 85%, preferably G*1 / G*C < 80%, - in the case where the tire (10) comprises first and second axially lateral portions (Pic, P2c) of the tread (52), G*1 / G*C < 85% and / or G*2 / G*C < 85%, preferably G*1 / G*C < 80% and / or G*2 / G*C < 80%.

5. Tire (10) according to any one of the preceding claims, wherein: - in the case where the tire (10) comprises an axially lateral portion (Pic) of the tread (52), G*1 / G*C > 40%, - in the case where the tire (10) comprises first and second axially lateral portions (Pic, P2c) of the tread (52), G*1 / G*C > 40% and / or G*2 / G*C > 40%.

6. A tire (10) according to any one of the preceding claims, wherein: - where the tire (10) comprises an axially lateral portion (Pic) of the tread (52), the axially central portion (POc) of the tread (52) is in contact with the axially lateral portion (Pic) of the tread (52) via an interface (56) arranged in the axially central portion (POb) of the tread (14), - where the tire (10) comprises first and second axially lateral portions (Pic, P2c) of the tread (52), the axially central portion (POc) of the tread (52) is in contact with each first and second axially lateral portion (Pic, P2c) of the tread (52) respectively via a first and a second interface (56, 58) arranged respectively in each first and second axially lateral portion (Gib,P2b) of the tread (14).,

7. Pneumatic (10) according to the preceding claim, wherein:

8.

9. - in the case where the tire (10) includes an axially lateral portion (Pic) of the tread (52), the axially central portion (POc) of the tread (52) extends axially from a first axial edge (18) of the tread surface (16) arranged on the opposite side with respect to the median plane (M) of the axially lateral portion (Pic) to the interface (56), - in the case where the tire (10) includes first and second axially lateral portions (Pic, P2c) of the tread (52), the axially central portion (POc) of the tread (52) extends axially from the first interface (56) to the second interface (58). Pneumatic (10) according to claim 6 or 7, wherein: - in the case where the tire (10) includes an axially lateral portion (Pic) of the tread layer (52), the axially lateral portion (Pic) extends axially from a second axial edge (20) of the tread surface (16) arranged on the same side of the median plane (M) as the axially lateral portion (Pic) of the tread layer (52) to the interface (56), - in the case where the tire (10) comprises first and second axially lateral portions (Pic, P2c) of the tread (52), the first axially lateral portion (Pic) of the tread (52) extends axially from a first axial edge (18) of the tread surface (16) arranged on the same side of the median plane (M) as the first axially lateral portion (Pic) of the tread (52) to the first interface (56) and the second axially lateral portion (P2c) of the tread (52) extends axially from a second axial edge (20) of the tread surface (16) arranged on the same side of the median plane (M) as the second axially lateral portion (P2c) of the tread (52) to the second interface (58). Pneumatic (10) according to any one of the preceding claims, wherein: - in the case where the tire (10) includes an axially lateral portion (Pic) of the tread (52), the average thickness (EOc) of the axially central portion (POc) of the tread (52) is strictly greater than the average thickness (Elc) of the axially lateral portion (Pic) of the tread (52), - in the case where the tire (10) includes first and second axially lateral portions (Pic, P2c) of the wearing course (52), the average thickness (EOc) of the axially central portion (POc) of the wearing course (52) is strictly greater than the average thickness (Elc, E2c) of each first and second axially lateral portion (Pic, P2c) of the wearing course (52).

10. Tire (10) according to any one of claims 1 to 9, wherein the tread (14) comprises a radially inner layer (54) arranged radially within the tread (52) and distinct from the tread (52), the radially inner layer (54) is arranged radially within: - the axially lateral portion (Pic) of the tread (52) in the case where the tire (10) comprises an axially lateral portion (Pic) of the tread (52) or of each first and second axially lateral portion (Pic, P2c) of the tread (52) in the case where the tire (10) comprises first and second axially lateral portions (Pic, P2c) of the tread (52), and - the axially central portion (POc) of the tread (52).

11. Tire (10) according to any one of claims 1 to 9, wherein the tread (14) comprises at least one radially inner layer (54), the or each radially inner layer (54) being formed in the lateral material (M1) in the case where the tire (10) comprises an axially lateral portion (Pic) of the tread (52) or in the first and / or in the second lateral material (M1, M2) of the tread (52) in the case where the tire (10) comprises first and second axially lateral portions (Pic, P2c; Pic) of the tread (52), the radially inner layer (54) being arranged radially inside the axially central portion (POc) of the tread (52).

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