Tire with reduced undercut and quiet tread

Abstract

The tire has a mean radial distance E1m between: - the surface (100) passing through the radially innermost point of the deepest cutout (26, 28) 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 of the radially outermost layer (72) such that E1m ≤ 2.0 mm. The first axially lateral portion comprises a linear density DR1 of first transverse grooves and a linear density DI1 of first transverse incisions satisfying DR1 ≤ 0.43 cm-1 and DR1 + DI1 ≥ 0.45 cm-1. Figure for abstract: Fig 4

Description

Title of the invention: Tire comprising a reduced undercut and a silent tread

[0001] The present invention relates to a tire, in particular for a passenger vehicle. By tire is meant a bandage intended to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure higher than atmospheric pressure. A tire according to the invention has a structure of substantially toroidal shape of revolution around a main axis of the tire.

[0002] A tire as described in WO2019 / 102148 is known from the state of the art. Despite its excellent performance, it has been noted that this tire generates external noise as well as improvable wet grip performance. Furthermore, in a continuous search to reduce vehicle fuel consumption, efforts are being made to reduce the rolling resistance of tires.

[0003] The aim of the invention is to reduce external noise without degrading rolling resistance and to improve grip on wet ground.

[0004] For this purpose, the subject of the invention is a tire comprising a crown comprising a tread and a crown reinforcement arranged radially inside the tread, the crown reinforcement comprising a radially outermost layer and comprising reinforcing elements embedded in a polymer matrix, the tread comprising main circumferential cutouts having a depth greater than or equal to 50% of the tread height comprising first and second axially outer main circumferential cutouts arranged axially on either side of the median plane of the tire, the first and second axially outer main circumferential cutouts being the axially outermost main circumferential cutouts of the tread, the tread comprising: - first and second axially lateral portions of the tread arranged axially outside respectively each first and second axially outer main circumferential cutout, an 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 average radial distance Elm in the axially central portion of the tread between: - the surface passing through the radially innermost point of the deepest cutout 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 directly above the axially central portion of the tread, is such that Elm < 2.0 mm, at least the first axially lateral portion comprises first transverse cutouts formed at least in part in the first axially lateral portion comprising: - first transverse grooves, first transverse incisions having a width strictly less than the width of the first transverse grooves, the linear density DR1 of first transverse grooves being defined by the ratio of the total number of first transverse grooves formed at least in part in the first axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, the linear density DU of first transverse incisions being defined by the ratio of the total number of first transverse incisions formed at least in part in the first axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, DR1 and DU satisfy DR1 < 0.43 cm-1 and DR1 + DU > 0.45 cm-1.

[0005] The tire according to the invention makes it possible to reduce external noise without degrading rolling resistance and to improve grip on wet ground compared to that described in WO2019 / 102148.

[0006] In order to reduce rolling resistance, the inventors designed a tire in which the mean radial distance Elm is relatively small, which makes it possible to reduce the thickness of material present between the two surfaces previously described and therefore makes it possible to reduce the shear present between the tread and the crown reinforcement and therefore to reduce the dissipation in the crown of the tire. However, the inventors discovered that this relatively small value of the mean radial distance Elm has the counterpart of stiffening the crown of the tire so that this crown generates more noise. Indeed, under the effect of an impact such as those which occur when the tread comes into contact with the rolling ground, a relatively rigid structure generates more noise than a relatively soft structure including a relatively high value of the mean radial distance Elm.

[0007] In order to compensate for this increase in noise generated by the crown of the tire, the inventors behind the invention have developed a tread which makes it possible to obtain lower noise compared to the tire described in WO2019 / 102148 independently of the gain in rolling resistance provided by the relatively reduced mean radial distance Elm and by improving wet grip. Indeed, the inventors have understood that wet grip is all the more important when the transverse cutouts are numerous. However, too many transverse cutouts, which are also too wide, lead to an increase in the external noise generated by the tire.Thus, the invention proposes to provide a large number of transverse cutouts and to distribute this large number between, on the one hand, transverse grooves whose relatively large width allows them to contribute mainly to grip on wet ground and, on the other hand, transverse incisions whose smaller width allows them to generate less noise than the transverse grooves while nevertheless guaranteeing a significant contribution to grip on wet ground.

[0008] 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 in the axial direction starting from the first and second axial edges of the axially central portion of the tread. Obviously, if the radially outermost point of the most radially outer reinforcing element among the reinforcing elements is radially outside the surface passing through the radially innermost point of the or each 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 radially outermost point of the most radially outer reinforcing element among the reinforcing elements is radially inside the surface passing through the radially innermost point of the or each deepest cutout and substantially parallel to the rolling surface, the measured radial distance is considered positive.

[0009] These measurements will be carried out in several meridian cutting planes equally distributed around the circumference of the tire, for example in four meridian cutting planes. The radial distances thus measured will then be averaged in order to obtain the average radial distance Elm.

[0010] 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 in the radial direction of the tire.

[0011] By vertically above the axially central portion of the tread, we mean the radially outer surface resulting from the projection in the radial direction of said axially central portion of the tread onto 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.

[0012] Conventionally, the tread surface is delimited axially by first and second axial edges which coincide 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 within the meaning of the ETRTO 2023 standard manual. The first and second axial edges are arranged on either side of the median plane of the tire and formed by lines substantially parallel to the circumferential direction of the tire. In the case of an obvious boundary between the tread surface and the rest of the tire, the first and second axial edges are determined simply.In the case 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.

[0013] A matrix is ​​said to be polymeric because it is based on a polymeric composition, this polymeric composition being able to comprise 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 compositions for tires, in particular compositions for embedding reinforcing elements.

[0014] Preferably, the polymer matrix is ​​an elastomeric matrix. By elastomeric matrix is ​​meant a matrix exhibiting, in the crosslinked state, elastomeric behavior. 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 comprises 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 other diene elastomer, a reinforcing filler such as carbon black, a system of vulcanization and usual additives. The adhesion between the wire reinforcement elements and the matrix in which they are embedded is ensured for example by a usual adhesive composition, for example an RFL type glue or equivalent glue such as for example described in WO2013017421 or WO2017168109.

[0015] By reinforcing element is meant an element allowing the mechanical reinforcement of the polymer matrix in which this reinforcing element is intended to be embedded. Preferably, each reinforcing element is wire-like, that is to say that each reinforcing element has a length at least 10 times greater than the largest dimension of its section regardless of the shape of the latter: circular, elliptical, oblong, polygonal, in particular rectangular or square or oval. In the case of a rectangular section, the wire-like reinforcing element has the shape of a strip.

[0016] 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 distant from each other by a non-zero distance, called the width of the cutout or of the portion of the cutout.

[0017] The main direction of a cutout is the direction along which the curve equidistant from each of the edges of the cutout to the radial dimension of the rolling surface passes. The curvilinear length is the length measured along this curve equidistant from each of the edges of the cutout to the radial dimension of the rolling surface, and this between each end of the cutout. The average direction is the shortest curve joining the two ends of the cutout.

[0018] The width of a cutout or a portion of a cutout is, on a new tire, the maximum distance between the two main lateral faces measured, by default and in the case where the cutout or the portion of the cutout does not include a chamfer, at a radial dimension coincident with the rolling surface, and by default and in the case where the cutout or the portion of the cutout includes a chamfer, at the radial dimension that is the most radially outermost of the cutout or the portion of the cutout and radially innermost of the chamfer. The width is measured substantially perpendicular to the main lateral faces. If a width other than the default width is specified, for example a width at a particular dimension, the width is equal to the distance between the two main lateral faces at the particular dimension of the cutout or the portion of the cutout.

[0019] The depth of a cutout or portion of a cutout is, on a new tire, the maximum radial distance between the bottom of the cutout or portion of the portion and its projection onto the ground when the tire rolls. The maximum value of the depths of the cuts is called the tread height. Preferably, the maximum value of the depths of the main circumferential cuts is called the tread height. Thus, preferably, the deepest cut in the tread is a main circumferential cut.

[0020] A cutout or a portion of a cutout may be transverse or circumferential.

[0021] A cutout or a transverse portion is such that the cutout extends in a mean 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 cutout or a transverse portion may be continuous, i.e. not be interrupted by a tread block or another cutout so that the two main lateral faces determining its length are uninterrupted over the length of the transverse cutout or portion.A cutout or a transverse portion may also be discontinuous, that is to say interrupted by one or more sculpture blocks and / or one or more cutouts so that the two main lateral faces determining its length are interrupted by one or more sculpture blocks and / or one or more cutouts.

[0022] A circumferential cutout or portion is such that the cutout or portion extends in a mean 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 cutout, the two ends coincide with each other and are joined by a curve making a complete turn of the tire. A circumferential cutout or portion may be continuous, i.e. not be interrupted by a tread block or another cutout so that the two main lateral faces determining its length are uninterrupted over the entire turn of the tire.A circumferential cutout may also be discontinuous, i.e. interrupted by one or more tread blocks and / or one or more cutouts so that the two main lateral faces determining its length are interrupted by one or more tread blocks and / or one or more cutouts over the entire circumference of the tire.

[0023] The tire according to the invention has a substantially toric shape around an axis of revolution substantially coincident with the axis of rotation of the tire. This axis of revolution defines three directions classically used by those skilled in the art: an axial direction, a circumferential direction and a radial direction.

[0024] By axial direction is meant the direction substantially parallel to the axis of revolution of the tire, i.e. the axis of rotation of the tire.

[0025] By circumferential direction is meant the direction which is substantially perpendicular to both the axial direction and a radius of the tire (in other words, tangent to a circle whose center is on the axis of rotation of the tire).

[0026] By radial direction is meant 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.

[0027] By median plane of the tire (noted M), we mean the plane perpendicular to the axis of rotation of the tire which is located at mid-axial distance of the two beads and which passes through the axial center of the crown reinforcement.

[0028] By equatorial circumferential plane of the tire is meant, in a meridian section plane, 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 meridian section 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 radially outermost point of the tread intended to be in contact with the ground and the radially innermost point of the tire intended to be in contact with a support, for example a rim.

[0029] By meridian plane is meant a plane parallel to the axis of rotation of the tire and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0030] By radially inner, respectively radially outer, is meant closer to the axis of rotation of the tire, respectively further from the axis of rotation of the tire. By axially inner, respectively axially outer, is meant closer to the median plane of the tire, respectively further from the median plane of the tire.

[0031] By bead is meant the portion of the tire intended to allow the tire to be attached to a mounting support, for example a wheel comprising a rim. Thus, each bead is in particular intended to be in contact with a hook on the rim allowing it to be attached.

[0032] 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., limits 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 up to b (i.e., including the strict limits a and b).

[0033] Unless otherwise stated, any angle made between two directions is the smallest of the angles made by those two directions with each other.

[0034] The tires are, in preferred embodiments of the invention, intended for passenger vehicles as defined within the meaning of the standard of the European Tyre and Rim Technical Organization or "ETRTO", 2023. Such a tire has a section in a meridian section plane characterized by a section height H and a nominal section width or flange thickness S within the meaning of the standard of the European Tyre and Rim Technical Organization or "ETRTO", 2023 such that the ratio H / S, expressed as a percentage, is at most equal to 90 and is at least equal to 20, and the nominal section width S is at least equal to 115 mm and at most equal to 385 mm. In addition, the hook diameter D, defining the diameter of the rim on which the tire is mounted, is at least equal to 12 inches and at most equal to 30 inches.

[0035] The tires are, in preferred embodiments of the invention, so-called summer tires. By summer, we mean tires which are neither so-called 4-season or all-season tires, nor so-called winter tires.

[0036] Winter tires are notably 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”). 4-season or all-season tires, due to their performance on snow, also have the M+S and / or 3PMSF markings. Thus, a summer tire does not have an M+S marking or a 3PMSF marking.

[0037] In advantageous but optional embodiments, the second axially lateral portion comprises second transverse cutouts formed at least in part in the second axially lateral portion comprising: - second transverse grooves, and - second transverse incisions having a width strictly less than the width of the second transverse grooves, the linear density DR2 of second transverse grooves being defined by the ratio of the total number of second transverse grooves provided at least partly in the second axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, the linear density DI2 of second transverse incisions being defined by the ratio of the total number of second transverse incisions made at least partly in the second axially lateral portion to the circumference of the tire measured on the median plane and inflated to 2.5 bars, DR2 and DI2 satisfy DR2 < 0.43 cm-1 and DR2 + DI2 > 0.45 cm-1.

[0038] Thus, the two axially lateral portions are used to reduce the noise generated by the tire.

[0039] In advantageous but optional embodiments, each first and / or second transverse groove has a width greater than or equal to 1.6 mm, preferably 1.8 mm and more preferably 2.0 mm.

[0040] In advantageous but optional embodiments, each first and / or second transverse groove has a width less than or equal to 7.0 mm, preferably 5.0 mm.

[0041] In advantageous but optional embodiments, each first and / or second transverse incision has a width less than or equal to 1.5 mm, preferably 1.2 mm, more preferably 1.0 mm and even more preferably 0.7 mm.

[0042] In advantageous but optional embodiments, each first and / or second transverse incision has a width greater than or equal to 0.2 mm, preferably 0.4 mm.

[0043] In advantageous but optional embodiments, DR1 + DU > 0.50 cm-1, preferably DR1 + DU > 0.55 cm-1, more preferably DR1 + DU > 0.60 cm-1, even more preferably DR1 + DU > 0.65 cm-1 and very preferably DR1 + DI1 >0.70 cm-1.

[0044] In the advantageous but optional embodiments in which the second axially lateral portion is used, DR2 + DI2 > 0.50 cm-1, preferably DR2 + DI2 > 0.55 cm-1, more preferably DR2 + DI2 > 0.60 cm-1, even more preferably DR2 + DI2 > 0.65 cm-1 and very preferably DR2 + DI2 > 0.70 cm-1.

[0045] Too few transverse cutouts lead to an increase in interior noise, particularly flapping noise, and especially when the tire is worn. Increasing the number of transverse cutouts helps reduce this interior noise.

[0046] In advantageous but optional embodiments, DR1 +DI1 < 0.90 cm-1, preferably DR1 +DI1 < 0.80 cm-1.

[0047] In the advantageous but optional embodiments in which the second axially lateral portion is used, DR2 +DI2 < 0.90 cm-1, preferably DR2 +DI2 < 0.80 cm-1.

[0048] Too many transverse cutouts, particularly transverse grooves, would increase the risk of generating too much noise.

[0049] In advantageous but optional embodiments, DR1 < 0.40 cm-1, preferably DR1 < 0.38 cm-1.

[0050] In the advantageous but optional embodiments in which the second axially lateral portion is used, DR2 < 0.40 cm-1, preferably DR2 < 0.38 cm-1.

[0051] By reducing the number of transverse grooves, the external noise generated by the tire is further reduced.

[0052] In advantageous but optional embodiments, DR1 > 0.30 cm-1, preferably DR1 > 0.35 cm-1.

[0053] In the advantageous but optional embodiments in which the second axially lateral portion is used, DR2 > 0.30 cm-1, preferably DR2 > 0.35 cm-1.

[0054] The wet grip performance is higher the higher the number of transverse cutouts, and therefore transverse grooves, is.

[0055] In advantageous but optional embodiments, DU > 0.29 cm-1, preferably DU > 0.32 cm-1 and more preferably DU > 0.34 cm-1.

[0056] In the advantageous but optional embodiments in which the second axially lateral portion is used, DI2 > 0.29 cm-1, preferably DI2 > 0.32 cm-1 and more preferably DI2 > 0.34 cm-1.

[0057] The wet grip performance is higher the higher the number of transverse incisions.

[0058] In advantageous but optional embodiments, DU < 0.43 cm-1, preferably DU < 0.40 cm-1 and more preferably DU < 0.38 cm-1.

[0059] In the advantageous but optional embodiments in which the second axially lateral portion is used, DI2 < 0.43 cm-1, preferably DI2 < 0.40 cm-1 and more preferably DI2 < 0.38 cm-1.

[0060] By reducing the number of transverse incisions, the rigidity of the corresponding axially lateral portion is increased, which makes it possible to improve both grip on dry ground and also to reduce wear of this axially lateral portion.

[0061] In advantageous but optional embodiments, the crown reinforcement comprises a working reinforcement comprising at least one working layer comprising metal reinforcing elements extending substantially parallel to each other, each metal reinforcing element comprising a metal monofilament.

[0062] A metal reinforcing element comprising a metal monofilament has a higher stiffness than a metal reinforcing element comprising an assembly of several metal monofilaments which has a relatively moderate stiffness due to the helix formed by the metal monofilaments. Furthermore, the use of metal reinforcing element metal monofilaments makes it possible to obtain working layers having relatively reduced thicknesses and therefore less dissipative compared to working layers using metal reinforcing elements comprising assemblies of several metal monofilaments. Thus, a metal reinforcing element comprising a metal monofilament makes it possible to further reduce the rolling resistance of the tire in return for an increase in the noise generated by the crown reinforcement of the tire which is, in accordance with the invention, effectively compensated by the tread.

[0063] In embodiments, the crown reinforcement comprising a hoop reinforcement, the radially outermost layer is a hoop layer.

[0064] Conventionally, the hoop reinforcement comprises several textile hoop reinforcement elements substantially parallel to each other embedded in the polymer matrix. In embodiments, the hoop reinforcement comprises a strip wound helically over several circumferential turns, the strip comprising several textile hoop reinforcement elements substantially parallel to each other and embedded in the polymer matrix.

[0065] Advantageously, each textile hooping wire reinforcement element extends in a main hooping direction forming, with the circumferential direction of the tire, an angle, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°.

[0066] Conventionally, the crown reinforcement comprises a working reinforcement arranged radially inside the hoop reinforcement, the working reinforcement advantageously comprising at least one working layer, the or each working layer comprising wire reinforcement elements extending substantially parallel to each other within each working layer. The wire reinforcement elements are preferably metal wire elements.Preferably, in the embodiments in which the working reinforcement comprises a radially inner working layer and a radially outer working layer arranged radially outside the radially inner working layer, the main direction in which each working cord reinforcement element of the radially innermost working layer extends and the main direction in which each working cord reinforcement element of the radially outermost working layer extends form, with the circumferential direction of the tire, angles of opposite orientations. The angles of opposite orientations may have equal or different absolute values.

[0067] Advantageously, the wire reinforcement elements of the or each working layer extend substantially parallel to each other in a direction forming an angle strictly greater than 10°, preferably ranging from 15° to 50° and more preferably ranging from 15° to 35° with the circumferential direction of the tire.

[0068] It will also be possible to envisage a hooping frame and a working frame as described in particular in US20190152262A1.

[0069] In advantageous but optional embodiments, Elm <1.9 mm, preferably Elm <1.8 mm. By further reducing the value of Elm, the rolling resistance is further reduced but the noise generated by the crown is increased, which is, in accordance with the invention, effectively compensated by the tread.

[0070] In advantageous but optional embodiments, the tire has a volumetric notch rate greater than or equal to 27.0%, preferably 28.0% and more preferably 29.0% and even more preferably ranging from 29.0% to 31.0%.

[0071] By opting for a relatively high volumetric notch ratio, wet grip performance is further promoted. In addition, the tread of a tire is all the more flexible the higher its volumetric notch ratio. Indeed, the more the tread is notched, the more it is likely to deform under the effect of forces, in particular at the level of its cutouts which form areas very favorable to deformation. Thus, the invention, by stiffening the crown by reducing Elm, is particularly advantageous in the case of a relatively notched tread.

[0072] The volumetric notch rate of the tread is the ratio of the total volume of the cutouts of the tread in the new condition to the total volume of the tread in the new condition but not including any cutouts. The tread is axially delimited by two planes perpendicular to the axis of rotation of the tire and passing through the axial edges of the tread surface. In order to measure such a volumetric notch rate, one of the methods described in WO2021 / 089958 may in particular be used.

[0073] In advantageous but optional embodiments, the tire has a tread height greater than or equal to 6.6 mm and preferably within a range from 6.6 to 7.7 mm.

[0074] Such a tread depth is relatively high and makes it possible to simultaneously improve the life of the tire while improving the grip performance on wet ground.

[0075] In advantageous but optional embodiments, the tread comprises a tread layer comprising an elastomeric material based on an elastomer, said to have a low glass transition temperature, having a glass transition temperature strictly less than or equal to -70°C, of preferably ranging from -70°C to -110°C, more preferably from -80°C to -110°C and even more preferably from -80°C to -100°C.

[0076] Such an elastomeric material makes it possible to significantly improve the resistance of the tread to wear and therefore to extend the service life of the tire. Such elastomeric materials are described in particular in WO2018115722 and WO2022162292. The glass transition temperature (Tg) of the elastomer is determined using a differential scanning calorimeter according to the ASTM E1356-08 (2014) standard.

[0077] By the expression "part by weight per hundred parts by weight of elastomer" (or pce), it is meant, within the meaning of the present invention, the part, by mass per hundred parts by mass of elastomer.

[0078] In the present application, unless expressly indicated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0079] By the expression "based on", we mean a material comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents having reacted with each other, at least partially, during the different phases of manufacture of the elastomeric material.

[0080] In advantageous but optional embodiments, the elastomeric matrix comprises at least 30 phr, preferably at least 40 phr of the low glass transition temperature elastomer. Optionally, the elastomeric matrix comprises at most 100 phr, preferably at most 70 phr and more preferably at most 60 phr of the low glass transition temperature elastomer.

[0081] In optional embodiments, the elastomeric matrix comprises only the low glass transition temperature elastomer. In other words, the elastomeric matrix is ​​comprised of the low glass transition temperature elastomer.

[0082] In other advantageous but optional embodiments, the elastomeric matrix of which the elastomeric material is based comprises an elastomer, said to have a high glass transition temperature, having a glass transition temperature strictly greater than -70°C, preferably ranging from -40°C to -70°C.

[0083] In embodiments wherein the elastomeric matrix comprises a high glass transition temperature elastomer, the elastomeric matrix comprises at least 30 phr, preferably at least 40 phr of the high glass transition temperature elastomer. Optionally, the elastomeric matrix comprises at most 70 phr, preferably at most 60 phr of the high glass transition temperature elastomer.

[0084] In advantageous but optional embodiments, the low glass transition temperature and / or high glass transition temperature elastomer comprises a copolymer based on butadiene and styrene. A "copolymer based on butadiene and styrene" is any copolymer obtained by copolymerization of one or more styrene compounds with one or more butadiene(s). Suitable styrene monomers include, in particular, styrene, methylstyrenes, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes. Suitable butadien monomers include, in particular, 1,3-butadiene. These elastomers can have any microstructure which depends on the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the quantities of modifying and / or randomizing agent used. The elastomers can be, for example, block, random, sequenced, microsequenced. Such butadiene and styrene-based copolymers can be obtained by a process as described in WO2021005295 or WO2022162292.In advantageous but optional embodiments, the butadiene-styrene copolymer is a butadiene-styrene copolymer (SBR). It will be noted that the SBR can be prepared in emulsion (ESBR) or in solution (SSBR). Whether it is ESBR or SSBR, the SBR can be of any microstructure compatible with a glass transition temperature below -70°C. In particular, the butadiene-styrene copolymer can have a styrene content of between 1% and 15% by weight and more particularly between 1% and 5%, a content (mol%) of -1,2 bonds of the butadiene part of between 4% and 25%. Advantageously, the butadiene-styrene copolymer is an SSBR.

[0085] Optionally, the elastomeric material is based on at least one reinforcing filler, known for its ability to reinforce an elastomeric material that can be used for the manufacture of tires. The reinforcing filler may comprise a carbon black, a reinforcing inorganic filler, for example a silica, or one of their mixtures. Examples of reinforcing fillers that can be used in the context of the invention are described in particular in WO2022162292.

[0086] Advantageously, the reinforcing filler comprises predominantly a reinforcing inorganic filler, preferably a silica. By predominant, it is meant, within the meaning of the present invention, that this compound is predominant among the compounds of the same type in the elastomeric material, that is to say that it is the one which represents the greatest quantity by mass among the compounds of the same type. Thus, a so-called predominant filler is that representing the greatest mass among the fillers of the elastomeric material. Preferably, by predominant, it is meant present at more than 50%, preferably more than 60%, 70%, 80%, 90%.

[0087] In optional but advantageous embodiments, the level of reinforcing filler in the elastomeric material of the tread layer of the tire may be within a range from 60 to 180 phr, preferably from 80 to 160 phr, preferably from 100 to 140 phr.

[0088] In optional but advantageous embodiments, the elastomeric material is based on at least one plasticizer comprising at least one plasticizing resin, the level of the plasticizing resin(s) may be within a range from 25 to 100 phr, preferably from 50 to 100 phr, more preferably from 55 to 90 phr.

[0089] The term “resin” is reserved in the present application, by definition known to those skilled in the art, for a compound which is solid at room temperature (23°C), as opposed to a liquid plasticizing compound such as an oil. Examples of plasticizing resins are described in more detail in WO2021 / 005295.

[0090] Although this is not necessary for the implementation of the present invention, the plasticizing system of the elastomeric material of the tread layer of the tire may comprise a liquid plasticizer at 23°C, for example such as those described in WO2021 / 005295.

[0091] Examples of other constituents that the elastomeric material may be based on are described in WO2022162292.

[0092] In advantageous but optional embodiments, the elastomeric material has a dynamic shear modulus measured at 23°C at 10% deformation and at a frequency of 10 Hz according to standard ASTM D 5992 - 96 greater than or equal to 1.70 MPa, preferably 1.85 MPa and more preferably 2.00 MPa.

[0093] Such a relatively high dynamic shear modulus makes it possible to improve grip on dry ground.

[0094] In advantageous but optional embodiments, the elastomeric material has a dynamic shear modulus measured at 23°C at 10% deformation and at a frequency of 10 Hz according to standard ASTM D 5992 - 96 strictly less than 2.30 MPa, preferably less than or equal to 2.25 MPa and more preferably less than or equal to 2.20 MPa.

[0095] Such a relatively moderate dynamic shear modulus makes it possible to further improve the longevity of the tire. In addition, the higher the dynamic shear modulus described above, the more dissipative the elastomeric material is and therefore degrades the rolling resistance performance. Thus, such a relatively moderate dynamic shear modulus also makes it possible to contain the rolling resistance.

[0096] In advantageous but optional embodiments, the elastomeric material has a dynamic shear modulus measured at 60°C and at an imposed stress of 0.7 MPa and at a frequency of 10 Hz according to standard ASTM D 5992 - 96 less than or equal to 1.30 MPa, preferably 1.20 MPa and more preferably 1.10 MPa.

[0097] Such a relatively moderate dynamic shear modulus allows for further improvement of wet grip.

[0098] Optionally, the elastomeric material has a dynamic shear modulus measured at 60°C and at an imposed stress of 0.7 MPa and at a frequency of 10 Hz according to standard ASTM D 5992 - 96 greater than or equal to 0.80 MPa, preferably 0.90 MPa.

[0099] Such a dynamic shear modulus makes it possible to avoid over-softening the tread layer and therefore to improve the longevity of the tire.

[0100] In advantageous but optional embodiments, said elastomeric material extends axially from the first axially lateral portion to the second axially lateral portion, preferably extending axially over the entire width of the tread.

[0101] Said elastomeric material extends axially from the first axially lateral portion to the second axially lateral portion means that at least a portion of the tread layer of each first and second axially lateral portion comprises said elastomeric material. Said elastomeric material extends axially across the entire width of the tread means that the entirety of the tread layer of each first and second axially lateral portion comprises said elastomeric material.

[0102] In advantageous but optional embodiments suitable for summer tires, the axially central portion of the tread comprises at least one central rib, the or each central rib being axially delimited by two axially adjacent main circumferential cutouts.

[0103] In advantageous but optional embodiments making it possible to reduce the noise generated by the tire, the or each central rib comprises transverse cutouts formed in said central rib, the transverse cutouts formed in said central rib extend in a mean direction forming an angle greater than or equal to 20°, preferably 25°, more preferably 30°, even more preferably 35° and very preferably 40° with the axial direction of the tire.

[0104] Indeed, by strongly inclining the average direction of the transverse cutouts with respect to the circumferential direction, the noise generated by the pumping of the air located between the transverse cutout and the ground is spread out in time when the transverse cutout is present in the contact area. Thus, the transverse cutouts contribute to the reduction of external noise on the one hand, by reducing the rigidity of the axially central portion of the tread and, on the other hand, by spreading the pumping noise of the inclined transverse cutouts.

[0105] The transverse cutouts made in said at least one of the central ribs are described in more detail in applications PCT / EP2024 / 056080 and PCT / EP2024 / 056087 filed in the name of the applicant of the present application.

[0106] In advantageous but optional embodiments, each transverse cutout provided in said central rib has a variable depth along said transverse cutout.

[0107] A counterpart of the high inclination of the transverse cutouts is the reduction in the drift rigidity. Indeed, the transverse cutouts create a discontinuity in the central part of the tread which softens this central part when transverse forces are applied. This softening is all the more important as the cutout extends in a direction close to a direction perpendicular to the forces. Thus, transverse cutouts make the central part less rigid with respect to the transverse forces applied in drift, hence the reduction in the drift rigidity. The more the transverse cutouts are inclined, i.e. the greater the angle, the more the drift rigidity decreases.In order to compensate for this reduction, instead of giving up the transverse cutouts, the depth of certain portions of the transverse cutouts is reduced, which makes it possible to restore the initial drift rigidity without losing the performance gain in external noise.

[0108] The characteristic that each transverse cutout provided in said central rib has a variable depth along said transverse cutout means that the depth is not constant over the entire width of said transverse cutout. Optionally, in order to advantageously stiffen the central rib, the ratio between the maximum depth and the minimum depth of said transverse cutout is greater than or equal to 1.2, preferably 1.5 and more preferably 1.7. Optionally, in order for each transverse cutout to provide a cutting function, the ratio between the maximum depth and the minimum depth of said transverse cutout is less than or equal to 3.0 and preferably 2.0.

[0109] Very advantageously, each transverse cutout made in said central rib comprises at least one portion, called reduced depth, having a depth less than or equal to 70%, preferably 60%, and more preferably 50% of the sculpture height continuously along said reduced depth portion.

[0110] The feature that the or each reduced depth portion has a continuously reduced maximum depth along said reduced depth portion ensures that the depth is reduced without interruption along the reduced depth portion.

[0111] The or each portion of reduced depth may have a constant or variable depth. The or each portion of reduced depth extends between two ends beyond which the condition(s) characterizing the portion of reduced depth is or are no longer satisfied, in particular the condition relating to the depth of the reduced depth portion.

[0112] In advantageous but optional embodiments making it possible to reduce the noise generated by the tire, it may be envisaged that the transverse cutouts made in said at least one of the central ribs are arranged as described in EP3065955, EP3065956, EP3292002, EP3292003, EP3292004, EP3535139, EP3535140, EP3535141 or even in EP4253090 and EP4253091.

[0113] 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 tread height, preferably from 5.0 mm to the tread height, and more preferably from 5.5 mm to the tread height.

[0114] 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 tread height, preferably 90% of the tread height.

[0115] 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.

[0116] In advantageous and optional variants, the tread comprises a radially inner layer arranged radially inside the tread layer and distinct from the tread layer.

[0117] In other variants, the tread does not comprise a radially inner layer. Thus, the tread layer is directly in contact with the crown reinforcement of the tire, for example as described above.

[0118] Conventionally, the tire comprises a crown, two sidewalls, two beads, 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 inward to the crown reinforcement.

[0119] In embodiments allowing the performance of so-called radial tires to be obtained, for example as defined by the ETRTO, the carcass reinforcement comprises at least one carcass layer, the or each carcass layer comprising carcass wire reinforcement elements, each carcass wire reinforcement element extending substantially in a main direction forming with the circumferential direction of the tire, an angle, in value absolute, ranging from 80° to 90°. Alternatively, it will be possible to have a variable angle ranging from 80° to 90° in at least one part of the flank and strictly less than 80° in at least one part of the top as described for example in US20190152262.

[0120] The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which: - [Fig.l] is a view, in a meridian section plane, of a tire according to the invention, - [Fig.2] is a top view of the tread of the tire of [Fig.l], - [Fig. 3] is a detailed view of the tread of the tire of Figures 1 and 2 illustrating the transverse cutouts, and - [Fig.4] is a detail view of an axially central part of the crown of the tire of figures 1 and 2.

[0121] In the figures relating to the tire, a reference X, Y, Z is shown corresponding to the usual axial (Y), radial (Z) and circumferential (X) directions of a tire.

[0122] Figures 1 to 4 show a tire according to the invention and designated by the general reference 10. The tire 10 has a substantially toric shape around an axis of revolution substantially parallel to the axial direction Y. The tire 10 is intended for a passenger vehicle and has dimensions 225 / 50 R17. In the various figures, the tire 10 is shown in new condition, that is to say not having yet been driven.

[0123] The tire 10 comprises a crown 12 comprising a tread 14 carrying a rolling surface 16 intended to come into contact with a ground when the tire 10 is rolling. The rolling surface 16 is delimited axially 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.

[0124] The tread 14 comprises an axially central portion POb of the tread 14 and first and second axially lateral portions Pib, P2b of the tread 14 arranged axially outside the axially central portion POb on either side axially of the axially central portion POb of the tread 14.

[0125] 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 the 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 axially outermost main circumferential cutouts of the tread 14 and below called axially outer main circumferential cutouts 22, 24.

[0126] The first axially lateral portion Pib and the second axially lateral portion P2b are arranged respectively axially outside the first axially outer main circumferential cutout 22 and the second axially outer main circumferential cutout 24. The first axially lateral portion Pib extends axially from the first axial edge 18 of the rolling surface 16 to the axially outer edge 19 of the first axially outer 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 outer edge 21 of the second axially outer 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.

[0127] As illustrated in [Fig.2], each main circumferential cutout 22 to 28 has a depth Hr ranging from 4.0 mm to the tread height Hs, preferably ranging from 5.0 mm to the tread height Hs and more preferably ranging from 5.5 mm to the tread height Hs. Each depth Hr is greater than or equal to 50%, preferably 75% and more preferably 90% of the tread height Hs. The tread height Hs is greater than or equal to 6.6 mm and preferably within a range from 6.6 mm to 7.7 mm. Here, Hs=7.0 mm, Hr=6.5 mm for each first and second axially outer main circumferential cutout 22, 24 and Hs=Hr=7.0 mm for each main circumferential cutout 26, 28. Each main circumferential cutout 22 to 28 respectively 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.

[0128] The axially central portion POb comprises central ribs and here first, second and third central ribs respectively designated by the references 32, 34, 36. Each central rib 32, 34, 36 is arranged axially between two of the axially adjacent main circumferential cutouts 22 to 28 and here delimited by two of the axially adjacent main circumferential cutouts 22 to 28. Each central rib 32, 34, 36 comprises transverse cutouts 38 40, 42 formed in the central ribs 32, 34, 36.

[0129] Each transverse cutout 38 opens into the circumferential cutouts 22, 26 in respectively the first and second opening zones Z1, Z2. The azimuth AZ1 of a point in the first opening zone AZ1 of a transverse cutout 38 is substantially circumferentially aligned with the azimuth AZ2 of a point in the second opening zone AZ2 of another of the transverse cutouts 38. Similarly, each transverse cutout 40 opens into the circumferential cutouts 26, 28 in respectively the first and second opening zones Z1, Z2. The azimuth AZ1 of a point of the first outlet zone AZ1 of a transverse cutout 40 is substantially circumferentially aligned with the azimuth AZ2 of a point of the second outlet zone AZ2 of another of the transverse cutouts 40.Similarly, each transverse cutout 42 opens into the circumferential cutouts 28, 24 in respectively the first and second opening zones Z1, Z2. The azimuth AZ1 of a point of the first opening zone AZ1 of a transverse cutout 42 is substantially circumferentially aligned with the azimuth AZ2 of a point of the second opening zone AZ2 of another of the transverse cutouts 42.

[0130] Each transverse cutout 38, 40, 42 extends between its first and second ends in a mean direction forming an angle greater than or equal to 20°, preferably 25°, more preferably 30°, even more preferably 35° and very preferably 40° with the axial direction Y of the tire 10. Here, each angle respectively denoted A3 8, A40, A42 with the axial direction Y of the tire 10 is such that A38=A40=A42=40°.

[0131] With reference to [Fig. 3], each transverse cutout 38, 42 has a variable depth along each transverse cutout 38, 42. Each transverse cutout 38, 42 comprises two portions 381, 383 and 421, 423 having a depth equal to 5.3 mm. Each transverse cutout 38, 42 comprises a portion 382, ​​422, called reduced depth, having a depth less than or equal to 70%, preferably 60% and more preferably 50% of the tread height Hs continuously along said reduced depth portion. Here, each portion 382, ​​422 has a depth equal to 2.8 mm. The ratio between the maximum depth, here 5.3 mm, and the minimum depth, here 2.8 mm, of each transverse cutout 38, 42 is greater than or equal to 1.2, preferably 1.5 and more preferably 1.7 and less than or equal to 3.0 and preferably 2.0 and here equal to 1.9.

[0132] Each transverse cutout 40 has a depth that is substantially constant along each transverse cutout 40 and equal to 5.4 mm.

[0133] Each transverse cutout 38, 40, 42 has a width less than or equal to 1.5 mm, preferably 1.2 mm, more preferably 1.0 mm and even more preferably 0.7 mm and greater than or equal to 0.2 mm, preferably 0.4 mm and here equal to 0.4 mm.

[0134] Each first and second axially lateral portion Pib, P2b respectively comprises a first and a second lateral rib respectively designated by the reference 44, 46. The tread 14 comprises first and second transverse cutouts 47, 50 formed at least in part in each first and second axially lateral portion Pib, P2b.

[0135] Each first and second transverse cutout 47, 50 extends between its first and second ends in a mean direction forming a substantially zero angle with the axial direction Y of the tire 10.

[0136] The first transverse cutouts 47 comprise first transverse grooves 48 and first transverse incisions 49 having a width strictly less than the width of the first transverse grooves 47. The second transverse cutouts 50 comprise second transverse grooves 51 and second transverse incisions 52 having a width strictly less than the width of the second transverse grooves 51.

[0137] With reference to [Fig. 3], each first and second transverse cutout 47, 50 has a variable depth along each first and second transverse cutout 47, 50. Each first and second transverse cutout 47, 50 comprises a portion 471, 501 having a depth equal to 5.2 mm and a portion 472, 502 having a depth equal to 2.8 mm.

[0138] Each first and second transverse groove 48, 51 has a width greater than or equal to 1.6 mm, preferably 1.8 mm and more preferably 2.0 mm and less than or equal to 7.0 mm, preferably 5.0 mm and here equal to 2.6 mm.

[0139] Each first and second transverse incision 49, 52 has a width less than or equal to 1.5 mm, preferably 1.2 mm, more preferably 1.0 mm and even more preferably 0.7 mm and greater than or equal to 0.2 mm, preferably 0.4 mm and here equal to 0.4 mm.

[0140] Each first and second linear density DR1, DR2 of transverse grooves is defined as the ratio of the total number of first and second transverse grooves 48, 51 formed respectively in each first and second axially lateral portions Pib, P2b to the circumference C of the tire 10 measured on the median plane M and inflated to 2.5 bars. Each first and second linear density DU, DI2 of transverse incisions is also defined as the ratio of the total number of first and second transverse incisions 49, 52 formed respectively in each first and second axially lateral portions Pib, P2b to the circumference C of the tire 10 measured on the median plane and inflated to 2.5 bars.

[0141] Thus, DR1 < 0.43 cm-1 and DR2 < 0.43 cm-1, preferably DR1 < 0.40 cm-1 and DR2 < 0.40 cm-1 and more preferably DR1 < 0.38 cm-1 and DR2 < 0.38 cm-1. In addition, DR1 > 0.30 cm-1 and DR2 > 0.30 cm-1, preferably DR1 > 0.35 cm-1 and DR2 > 0.35 cm-1. In addition, DU > 0.29 cm-1 and DI2 > 0.29 cm-1, preferably DU > 0.32 cm-1 and DI2 > 0.32 cm-1 and more preferably DU > 0.34 cm-1 and DI2 > 0.34 cm-1. In addition, DU < 0.43 cm-1 and DI2 < 0.43 cm-1, preferably DU < 0.40 cm-1 and DI2 < 0.40 cm-1 and more preferably DU < 0.38 and DI2 < 0.38.

[0142] Furthermore, DR1 + DU > 0.45 cm-1 and DR2 + DI2 > 0.45 cm-1, preferably DR1 + DU > 0.50 cm-1 and DR2 + DI2 > 0.50 cm-1, more preferably DR1 + DU > 0.55 cm-1 and DR2 + DI2 > 0.55 cm-1, even more preferably DR1 + DU > 0.60 cm-1 and DR2 + DI2 > 0.60 cm-1, very preferably DR1 + DU > 0.65 cm-1 and DR2 + DI2 > 0.65 cm-1 and extremely preferably DR1 + DU > 0.70 cm-1 and DR2 + DI2 > 0.70 cm-1. In addition, DR1 +DI1 < 0.90 cm-1 and DR2 +DI2 < 0.90 cm-1 and preferably DR1 +DI1 < 0.80 cm-1 and DR2 +DI2 < 0.80 cm-1.

[0143] The tire 10 has a circumference C here equal to 207 cm, 75 first transverse grooves 48, 75 first transverse incisions 49, 75 second transverse grooves 51 and 75 second transverse incisions 52 so that here DR1=DR2=0.36 cm-1, DI1=DI2=0.36 cm-1 and DR1 +DI1= DR2 +DI2=0.72 cm-1.

[0144] All the transverse cutouts described above are provided with chamfers which are not shown.

[0145] Due to the presence of the various transverse cutouts previously described, the tread 14 has a volumetric notch rate TEV greater than or equal to 27.0%, preferably 28.0% and more preferably 29.0% and even more preferably ranging from 29.0% to 31.0% and here equal to 30.0%.

[0146] The tread 14 comprises a tread layer 53 and a radially inner layer 54 arranged radially inside the tread layer 53 and distinct from the tread layer 53.

[0147] The wearing course 53 comprises an elastomeric material MO having a dynamic shear modulus G*0 measured at 23°C at 10% deformation and at a frequency of 10 Hz according to the standard ASTM D 5992-96 greater than or equal to 1.70 MPa, preferably 1.85 MPa and more preferably 2.00 MPa and strictly less than 2.30 MPa, preferably less than or equal to 2.25 MPa and more preferably less than or equal to 2.20 MPa and here equal to 2.15 MPa. The elastomeric material MO has a shore hardness DS equal to 61. The wearing course 53 has a dynamic shear modulus G*'0 measured at 60°C and at imposed stress (0.7 MPa) greater than or equal to 0.80 MPa, preferably 0.90 MPa and less than or equal to 1.30 MPa, preferably 1.20 MPa and more preferably 1.10 MPa and here equal to 1.05 MPa. The wearing course 53 has a dynamic loss maximum tanDMAX23-0 equal to 0.37 and a glass transition temperature TgO equal to -13°C. The elastomeric material MO extends axially from the first axially lateral portion Pib to the second axially lateral portion P2b, and here extends axially over the entire width LSR of the tread 14.

[0148] The radially inner layer 54 comprises an elastomeric material MS. In practice, and as is usually done in the tire industry, the radially inner layer 54 comprises the elastomeric material MS as well as a significant proportion of elastomeric material MO, for example between 40% and 60% by mass of the material MO.

[0149] 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 viscoanalyzer using specimens comprising a cured composition extracted from the tire. The response of the specimen subjected to alternating simple sinusoidal shear stress is recorded at a frequency of 10 Hz under determined temperature conditions (here 23°C) according to the ASTM D1349-99 standard. A strain amplitude sweep is carried out from 0.1% cc to 100% cc (forward cycle), then from 100% cc to 0.1% cc (return cycle), cc meaning peak-peak. The test piece is of cylindrical 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 dynamic complex shear modulus G* is defined as the square root of the sum of the square of G' and the square of G” in which G' represents the elastic modulus and G' ' represents the viscous modulus. The complex shear modulus G* is measured at 10% cc strain on the return cycle.

[0150] Shore hardness is for example measured according to JIS K6253 standard at 23°C using a type A durometer.

[0151] The complex shear modulus G*' at imposed stress is determined using a Metravib VA4000 or DMA+450 type viscoanalyzer using specimens comprising a cured composition extracted from the tire. The response of the specimens subjected to alternating simple sinusoidal shear stress is recorded at a frequency of 10 Hz under a force equal to 55 N. A temperature scan is carried out between -80°C and 80°C at a speed of 1.5°C / min, having previously accommodated the specimens at 100% peak-peak strain at a temperature less than or equal to 40°C, for example 23°C. The test piece 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]. Note that the force of 55 N is equivalent, in the case of a specimen with a diameter equal to 10.00 mm, to a stress of an amplitude equal to 0.7 MPa peak-peak. The complex shear modulus G*' is measured at 60°C.

[0152] The dynamic loss tanDMAX23 is yet another dynamic property well known to those skilled in the art and is measured on the same viscoanalyzer of the Metravib VA4000 or DMA+450 type using specimens comprising a cured composition extracted from the tire. The response of the specimen subjected to a sinusoidal stress in alternating simple shear is recorded, at a frequency of 10 Hz under determined temperature conditions (here 23°C) according to the ASTM DI349-99 standard. A strain amplitude sweep is carried out from 0.1% cc to 100% cc (forward cycle), then from 100% cc to 0.1% cc (return cycle), cc meaning peak-peak. The specimen is of cylindrical 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 reflects 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.

[0153] The glass transition temperature Tg is determined using a Metravib VA4000 or DMA+450 type viscoanalyzer using test pieces comprising a cured composition extracted from the tire. The response of the test pieces subjected to alternating simple sinusoidal shear stress at a frequency of 10 Hz under a force equal to 55 N is recorded. A temperature scan is carried out between -80°C and 80°C at a speed of 1.5°C / min. The test piece has a cylindrical section as described in ASTM D 5992-96 (version reapproved in 2011, initially 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 the force of 55 N is equivalent, in the case of a test piece with a diameter equal to 10.00 mm, to a stress of an amplitude equal to 0.7 MPa peak-peak.The glass transition temperature Tg is taken equal to the temperature for which the value of 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 reflects a dynamic loss and is equal to the ratio G” / G'.

[0154] Table 1 below shows the composition from which the MO material was manufactured in a conventional manner known to those skilled in the art. The values ​​are given in pce.

[0155] [Tables 1] Composition MO Elastomer 1 (1) 30-100 Elastomer 2 (2) 0-70 Filler(s) (3) 60-180 Silane (4) 5-50 Resin (5) 25-100 Other additives (6) 5-40

[0156] (1) - Styrene-Butadiene Elastomer described as polymer E on page 34 of WO2018115722; (2) - Styrene-Butadiene Elastomer described as control polymer A on page 39 of WO2022162292; (3) - Carbon black grade 234 according to ASTM D-1765 and Silica 160MP from Solvay; (4) - Silane selected from “Si69” and “Si75” from Evonik; (5) - “PR-383” Hydrogenated DCPD resin; (6) - The other additives are conventionally known to those skilled in the art and include here in particular a protective wax, N1,3-dimethylbutyl-N-phenylparaphenylenediamine, N-cyclohexyl-benzothiazyl sulphenamide, diphenylguanidine, sulphur, stearic acid, zinc oxide, oleic sunflower oil.

[0157] It will be noted in particular that the elastomeric material MO is based on an elastomeric matrix comprising the elastomer (1), said to have a low glass transition temperature, having a glass transition temperature less than or equal to -70°C, preferably ranging from -70°C to -110°C, more preferably from -80°C to -110°C and even more preferably from -80°C to -100°C and here equal to -88°C. The elastomeric matrix of which the elastomeric material MO may comprise the elastomer (2), said to have a high glass transition temperature, having a glass transition temperature strictly greater than -70°C, preferably ranging from -40°C to -70°C and here equal to -65°C.

[0158] With reference to Figures 1 and 4, the crown 12 comprises a crown reinforcement 60 extending in the crown 12 in the circumferential direction X. The tire 10 also comprises a sealing layer 62 to an inflation gas being intended to delimit an internal cavity closed with a mounting support of the tire 10 once the tire 10 is mounted on the mounting support, for example a rim. The crown reinforcement 60 comprises a working reinforcement 64 and a hooping reinforcement 66.

[0159] The working reinforcement 64 comprises two working layers 68, 70. The radially outer working layer 70 is arranged radially outside the radially inner working layer 68.

[0160] The hoop reinforcement 66 comprises at least one hoop layer and here comprises a hoop layer 72.

[0161] The crown reinforcement 60 is arranged radially inside the tread 14. The hoop reinforcement 66, here the hoop layer 72, is arranged radially outside the working reinforcement 64 and radially inside the tread 14. The hoop reinforcement 66 is therefore radially interposed between the working reinforcement 64 and the tread 14. The hoop layer 72 is therefore the radially outermost layer of the crown reinforcement 60.

[0162] The tire 10 comprises two sidewalls 74 extending the crown 12 radially inwards. The tire 10 further comprises two beads 76 radially inwards to the sidewalls 74. Each sidewall 74 connects each bead 76 to the crown 12.

[0163] The tire 10 comprises a carcass reinforcement 78 anchored in each bead 76, in this case is wound around two bead wires 80. The carcass reinforcement 78 extends radially in each sidewall 74 and axially in the crown 12 radially inside the crown reinforcement 60. The crown reinforcement 60 is arranged radially between the tread 14 and the carcass reinforcement 78. The carcass reinforcement 78 comprises at least one carcass layer and here comprises a single carcass layer 82.

[0164] With reference to [Fig. 4], each working layer 68, 70, hooping layer 72 and carcass layer 82 comprises a polymer 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 respectively comprises working wire reinforcement elements 680, 700, the hooping layer 72 comprises hooping wire reinforcement elements 720 and the carcass layer 82 comprises carcass wire reinforcement elements 820.

[0165] The wire hoop reinforcement elements 720 are textile and are wound circumferentially helically in a main direction forming, with the circumferential direction X of the tire 10, an angle, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°.

[0166] The working wire reinforcement elements 680, 700 are metallic and extend substantially parallel to each other within each working layer 68, 70 in main directions forming with the circumferential direction X of the tire 10, angles of opposite orientations between the two working layers 68, 70 and in absolute value, strictly greater than 10°, preferably ranging from 15° to 50° and more preferably ranging from 15° to 30° and here equal to -26° and +26°. Each working wire reinforcement element 680, 700 comprises a metallic monofilament having a diameter equal to 0.32 mm.

[0167] The carcass wire reinforcement elements 820 are textile and extend in a main direction forming with the circumferential direction X of the tire 10, an angle, in absolute value, greater than or equal to 60°, preferably ranging from 80° to 90° and here substantially equal to 90°.

[0168] Each hoop wire reinforcement element 720 and carcass 820 is, for example, identical to those described in applications WO2021250331, WO2022074341 or WO2022069819.

[0169] The interfaces between two adjacent layers are represented by dashed lines. In [Fig.4], we have represented: - the surface 100 passing through the radially innermost point of the deepest cutout made 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 cutouts 26, 28 and substantially parallel to the tread surface 16, - the radially outer surface 102 passing through the radially outermost points of the radially outermost hooping wire reinforcement elements 720 among the hooping wire reinforcement elements 720 of the radially outermost layer 72 arranged directly above the axially central portion POb of the tread 14.

[0170] 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 < 2.0 mm and preferably Elm < 1.9 mm, more preferably Elm < 1.8 mm. Furthermore, Elm > 0.5 mm, preferably Elm > 1.0 mm. In this case, El=1.7 mm.

[0171] COMPARATIVE TESTS

[0172] Tires 10, 11 and 12 according to the invention were compared with control tires T0, T1 and T2 whose characteristics are indicated in Table 2 below and in which the results of rolling resistance (RR), exterior noise, wet grip and interior noise tests were collected.

[0173] The results of the various tests are given with reference to the control tire T0.

[0174] The rolling resistance test was conducted according to ISO 28580:2018. For a tested tire, the result is the rolling resistance coefficient which represents the ratio of the force resisting the vehicle's forward movement by hysteresis of the tire divided by the load carried. A reduction in rolling resistance corresponds to an improvement in performance.

[0175] The external noise was measured by driving the vehicle on a track compliant with ISO 10844 regulations and certified by UTAC. A delimited measurement area on the track was equipped with Müller-BBM vibro-acoustic acquisition equipment. The noise generated by each engine-off tire at a speed of 80 km / h was measured (conditions similar to those used in the RI 17 regulation). The raw noise measured was then corrected for ground temperature as specified in the RI 17 UN regulation. A reduction in external noise corresponds to an improvement in performance.

[0176] The wet grip test is conducted by measuring the distance traveled during deceleration from a speed of 80 km / h to a speed of 20 km / h with a water depth of 1 mm. The shorter the braking distance, the better the tire performance. A result above 100 indicates an improvement compared to the control tire T0.

[0177] The interior noise test is a subjective test conducted by an experienced driver regarding the interior noise of the vehicle. A “-” sign corresponds to an increase in interior noise and an “=” sign corresponds to interior noise perceived at the same level.

[0178] [Tables2] T0 Tl T2 10 Il 12 DR1 (cm-1) 0.44 0.44 0.55 0.28 0.36 0.36 DU (cm-1) 0.00 0.00 0.00 0.28 0.36 0.36 DR2(cm-l) 0.44 0.44 0.55 0.28 0.36 0.36 DI2 (cm-1) 0.00 0.00 0.00 0.28 0.36 0.36 DR1+DI1 (cm-1) 0.44 0.44 0.55 0.56 0.72 0.72 DR2+DI2 (cm-1) 0.44 0.44 0.55 0.56 0.72 0.72 Elm (mm) 2.0 1.5 2.0 2.0 2.0 1.7 TEV (%) 26.5 26.5 27.5 27.5 30.0 30.0 Hs (mm) 6.5 6.5 7.0 7.0 7.0 7.0 RR(kg / t) Ref -0.15 -0.1 -0.1 -0.1 -0.2 External noise (dB) Ref +0.6 +0.5 -0.2 -0.2 0 Wet grip 100 98 102 103 105 103 Internal noise Ref - - = -

[0179] The results of the tests previously described show a reduction in exterior noise without degradation of rolling resistance as well as an improvement in wet grip of tires 10, 11 and 12 compared to tires T0, T1, T2.

[0180] The comparison of the T0 and Tl tires shows that the reduction of Elm leads to a strong reduction in rolling resistance in return for a strong increase in the external and internal noise generated by the top of the tire.

[0181] In particular, the tires 10, II, 12 each satisfy the characteristic according to which DR1 < 0.43 cm-1 and DR1 + DU > 0.45 cm-1 which makes it possible to reduce the external noise generated by the sculpture. This reduction in external noise makes it possible to compensate for the increase in external noise due to the reduction in the value of Elm as shown by the comparison of the tires T0, Tl, 10, II and 12.

[0182] The comparison of the T2 and 10 tires shows that too high a value of DR1 in the T2 tire leads to a strong increase in the external noise generated by the sculpture, whereas the introduction of incisions and the reduction of DR1 simultaneously makes it possible to reduce the external noise generated by the sculpture and to improve grip on wet ground.

[0183] Finally, the comparison of tires 10 and II shows that the increase in DR1 + DU makes it possible to reduce the interior noise. By reducing the value of Elm of tire II, the rolling resistance of tire 12 is reduced by accepting the increase in interior noise compared to tires T0 and II, the same exterior noise as tire T0 and by improving wet grip compared to tires T0, T1 and T2.

[0184] It may also be provided that the tread comprises noise reduction devices, in particular Helmholtz resonators as described for example in EP0989000, EP2011671, EP2240335, EP2627524.

[0185] It may also be provided that the tire comprises a noise reduction device as described in WO2022 / 069822 or as described in EP1219944, EP1253025, EPI 184207, EPI 110763, EP1876038.

Claims

1. Claims A tire (10) comprising a crown (12) comprising a tread (14) and a crown reinforcement (60) arranged radially inside the tread (14), the crown reinforcement (60) comprising a radially outermost layer (72) and comprising reinforcing elements (720) embedded in a polymer matrix, the tread (14) comprising main circumferential cutouts (22, 24, 26, 28) having a depth greater than or equal to 50% of the tread height (Hs) comprising first and second axially outer main circumferential cutouts (22, 24) arranged axially on either side of the median plane (M) of the tire (10), the first and second axially outer main circumferential cutouts (22, 24) being the axially outermost main circumferential cutouts of the tread (14), the tread rolling bearing (14) comprising: - first and second axially lateral portions (Pib, P2b) of the tread (14) arranged axially outside respectively each first and second axially outer main circumferential cutout (22, 24), - an 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 portion (P2b) of the tread (14), characterized in that 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 cutout (26, 28) made in the axially central portion (POb) of the tread (14) and substantially parallel to the tread 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 of the layer radially outermost (72) arranged in line with the axially central portion (POb) of the tread (14), is such that Elm < 2.0 mm and in that at least the first axially lateral portion (Pib) comprises first transverse cutouts (47) formed at least in part in the first axially lateral portion (Pib) comprising: - first transverse grooves (48), - first transverse incisions (49) having a width strictly less than the width of the first transverse grooves (48), the linear density DR1 of first transverse grooves (48) being defined by the ratio of the total number of first transverse grooves (48) formed at least in part in the first axially lateral portion (Pib) to the circumference of the tire measured on the median plane (M) and inflated to 2.5 bars,the linear density DU of first transverse incisions (49) being defined by the ratio of the total number of first transverse incisions (49) made at least partly in the first axially lateral portion (P2b) to the circumference of the tire measured on the median plane (M) and inflated to 2.5 bars, DR1 and DU satisfy DR1 < 0.43 cm-1 and DR1 + DU > 0.45 cm-1.,

2. A tire (10) according to the preceding claim, wherein the second axially lateral portion (P2b) comprises second transverse cutouts (50) formed at least in part in the second axially lateral portion (P2b) comprising: - second transverse grooves (51), and - second transverse incisions (52) having a width strictly less than the width of the second transverse grooves (51), the linear density DR2 of second transverse grooves (51) being defined by the ratio of the total number of second transverse grooves (51) formed at least in part in the second axially lateral portion (P2b) to the circumference of the tire measured on the median plane (M) and inflated to 2.5 bars, the linear density DI2 of second transverse incisions (52) being defined by the ratio of the total number of second transverse incisions (52) formed at least in part in the second axially lateral portion (P2b) on the circumference of the tire measured on the median plane (M) and inflated to 2.5 bars, DR2 and DI2 satisfy DR2 < 0.43 cm-1 and DR2 + DI2 > 0.45 cm-1.

3. Tire (10) according to any one of the preceding claims, in which DR1 + DU > 0.50 cm-1, preferably DR1 + DU > 0.55 cm-1, more preferably DR1 + DU > 0.60 cm-1, even more preferably DR1 + DU > 0.65 cm-1 and very preferably DR1 + DU > 0.70 cm-1.

4. A tire (10) according to any preceding claim, wherein DR1 < 0.40 cm-1, preferably DR1 < 0.38 cm-1.

5. A tire (10) according to any preceding claim, wherein DR1 > 0.30 cm-1, preferably DR1 > 0.35 cm-1.

6. A tire (10) according to any one of the preceding claims, wherein DU > 0.29 cm-1, preferably DU > 0.32 cm-1 and more preferably DU > 0.34 cm-1.

7. A tire (10) according to any one of the preceding claims, wherein DU < 0.43 cm-1, preferably DU < 0.40 cm-1 and more preferably DU < 0.38 cm-1.

8. A tire (10) according to any preceding claim, wherein the crown reinforcement (60) comprises a working reinforcement (64) comprising at least one working layer (68, 70) comprising metal reinforcing elements (680, 700) extending substantially parallel to each other, each metal reinforcing element (680, 700) comprising a metal monofilament.

9. Tire (10) according to any one of the preceding claims, having a volumetric notch rate greater than or equal to 27.0%, preferably 28.0% and more preferably 29.0% and even more preferably ranging from 29.0% to 31.0%.

10. Tire (10) according to any one of the preceding claims, having a tread height (Hs) greater than or equal to 6.6 mm and preferably within a range from 6.6 to 7.7 mm.

11. A tire (10) according to any preceding claim, wherein the tread (14) comprises a tread layer (53) comprising elastomeric material (MO) based on an elastomer having a glass transition temperature strictly less than or equal to -70°C, preferably ranging from -70°C to -110°C, preferably from -80°C to -110°C and even more preferably from -80° to -100°C.

12. A tire (10) according to any one of the preceding claims, wherein the axially central portion (POb) of the tread (14) comprises at least one central rib (32, 34, 36), the or each central rib (32, 34, 36) being axially delimited by two axially adjacent main circumferential cutouts (22, 24, 26, 28).

13. Tire (10) according to the preceding claim, wherein the or each central rib (32, 34, 36) comprises transverse cutouts (38, 40, 42) formed in said central rib (32, 34, 36), the transverse cutouts (38, 40, 42) formed in said central rib (32, 34, 36) extend in a mean direction forming an angle greater than or equal to 20°, preferably 25°, more preferably 30°, even more preferably 35° and very preferably 40° with the axial direction (Y) of the tire (10).

14. A tire (10) according to the preceding claim, wherein each transverse cutout (38, 42) formed in said central rib (32, 36) has a variable depth along said transverse cutout (38, 42).

15. Tire (10) according to the preceding claim, in which each transverse cutout (38, 42) formed in said central rib (32, 36) comprises at least one portion (382, 422), called reduced depth, having a depth less than or equal to 70%, preferably 60% and more preferably 50% of the tread pattern height (Hs) continuously along said reduced depth portion (382, 422).

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