Pneumatic system comprising a durable stiffening structure and an interface between outer and inner layers

Abstract

The tire (10) comprises a crest (12), first and second sidewalls (30A, 30B), first and second bead (32A, 32B), an internal surface (34) delimiting a toroidal cavity (36), a first outer layer (33A) arranged radially and / or axially outside a first inner layer (37A) and in contact with the first inner layer (37A), a stiffening structure (52) extending continuously in the toroidal cavity (36) from the first sidewall (30A) and / or bead (32A) to the crest (12), passing through the first inner layer (37A) and penetrating at least partially the first outer layer (33A). The ratio of moduli between a nominal secant modulus at 10% elongation of the first outer layer (33A) and a nominal secant modulus at 10% elongation of the first inner layer (37A) is strictly greater than 1.0. Figure for the abbreviation: Fig 1

Description

Title of the invention: A tire comprising a durable stiffening structure and an interface between outer and inner layers technical field

[0001] The present invention relates to a tire, in particular for passenger vehicles.

[0002] By pneumatic tire, we mean a tire designed to form a cavity by cooperating with a mounting support, for example a rim, this cavity being capable of being pressurized to a pressure greater than atmospheric pressure. A pneumatic tire has a substantially toroidal shape of revolution around a principal axis of the tire, this principal axis coinciding with the axis of rotation of the tire. Previous techniques

[0003] A tire for use on a passenger vehicle, described in WO2020 / 128225, is known from the prior art. The tire described comprises a crown extended radially inward on each side of the tire's median plane by first and second sidewalls, and then by first and second bead sections designed to contact a mounting support, for example, a rim. Each first and second bead section includes a circumferential reinforcing element designed to secure the tire to the mounting support.

[0004] The tire includes an internal surface delimiting a toroidal cavity for inflating the tire once the latter is mounted on the mounting support.

[0005] The tire described in WO2020 / 128225 includes a stiffening structure comprising first stiffening elements extending continuously in the toroidal cavity from the first bead to the apex and second stiffening elements extending continuously in the toroidal cavity from the second bead to the apex.

[0006] Each first and second stiffening element is attached to each bead from which it extends by means of a bead interface between the stiffening element and a portion of the inner surface of the bead. Similarly, each first and second stiffening element is attached to the crown of the tire by means of a crown interface between the stiffening element and a portion of the inner surface of the crown. Each bead-crown interface comprises an elastomeric compound cushion positioned between the stiffening element and the portion of the corresponding internal surface.

[0007] It was noted that each bead and apex interface was subjected to tensile stress. Such interfaces are sensitive to repeated stresses which can lead to premature separation between the stiffening elements and the inner surface of the bead and / or the inner surface, and therefore to premature destruction of the stiffening structure.

[0008] The durability of the tire described in WO2020 / 128225 was improved in WO2022 / 200717 through the use of anchoring for each first and second stiffening element within the tire's internal structure. Nevertheless, the durability of the tire described in WO2022 / 200717, particularly the durability of the anchoring of the first and second stiffening elements in each first and / or second sidewall and / or bead, while significantly improved compared to that of the tire described in WO2020 / 128225, could not be further enhanced. Indeed, it was observed that the stiffening structure deteriorated due to the dislodging of the stiffening elements in one of the first and second beads.

[0009] The invention aims to improve the durability of the stiffening structure described in WO2020 / 128225 and to reduce the occurrence of dislodgement of the tire stiffening elements described in WO2022 / 200717. Description of the invention

[0010] The invention relates to a tire comprising a crown, first and second sidewalls each extending radially inwards from the crown, first and second bead extensions respectively extending radially inwards from the first and second sidewalls, the tire being provided with an internal surface delimiting a toroidal inflation cavity of the tire, the tire comprising:

[0011] - a first inner layer forming at least part of the first sidewall and / or the ridge and / or the top,

[0012] - a first outer layer forming at least part of the first flank and / or bead and / or apex, and arranged radially and / or axially on the outside of the first inner layer while being in contact with the first inner layer,

[0013] - a stiffening structure extending continuously into the toric cavity from at least the first flank and / or ridge up to at least the top and being anchored in the first flank and / or ridge and / or in the top by extending into the first flank and / or ridge and / or the top, said stiffening structure passing through the first inner layer and penetrating at least partially the first outer layer into the first flank and / or ridge and / or the top,

[0014] pneumatic system in which a first ratio of modules between a secant module nominal at 10% elongation of the first outer layer and a nominal secant modulus at 10% elongation of the first inner layer is strictly greater than 1.0.

[0015] As explained below, the invention functions as soon as it is applied to only one side of the tire, here at least to the side comprising the first sidewall and / or bead. Advantageous embodiments allow the invention to be applied to both sides of the tire, although this is not necessary to realize the invention. Thus, in the present application, the use of the term "first" is intended, unless otherwise obviously interpreted, to associate the element designated as "first" with the first sidewall and / or bead. Similarly, the use of the term "second" is intended, unless otherwise obviously interpreted, to associate the element designated as "second" with the second sidewall and / or bead.

[0016] Advantageously, the first sidewall and / or bead is arranged on the same side of the tire's median plane as the outer side of the tire. Thus, the rigidity structure acts on the side of the tire most stressed during high-skid conditions. By inner and outer sides, it is understood that the tire is designed so that one of its sides is arranged on the inside and the other on the outside. This orientation, imposed by the tire manufacturer, ensures that the tire performs as expected. Indeed, mounting a tire with an orientation different from that imposed by the manufacturer can lead to suboptimal vehicle behavior. By outer side, it is understood that the side of the tire is fully visible from outside the vehicle when the tire is mounted on the vehicle.The inside 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 inside and outside sides.

[0017] In a preferred embodiment in which the stiffening structure performs its function on both sides of the median plane of the tire, thus enabling homogeneous tire behavior, the tire comprises:

[0018] - a second inner layer forming in part at least the second flank and / or the ridge and / or the top,

[0019] - a second outer layer forming in part at least the second flank and / or the ridge and / or the apex, and arranged radially and / or axially on the outside of the second inner layer while being in contact with the second inner layer,

[0020] the stiffening structure extending continuously in the toroidal cavity from at least the second flank and / or bead to at least the apex and being anchored in the second flank and / or bead and / or in the apex by extending into the second flank and / or bead and / or in the apex, said stiffening structure traversing the second inner layer and penetrating at least partially the second outer layer into the second flank and / or ridge and / or the summit,

[0021] a second ratio of moduli between a nominal secant modulus at 10% elongation of the second outer layer and a nominal secant modulus at 10% elongation of the second inner layer is strictly greater than 1.0.

[0022] The nominal secant modulus measurements at 10% elongation are the elastic moduli of the layer compositions measured during a uniaxial tensile test at an elongation value of 0.1 (i.e., 10% elongation, expressed as a percentage). A constant uniaxial tensile speed is applied to the specimen, and its elongation and the stress are measured. The measurement is performed using an INSTRON®-type tensile testing machine at a temperature of 23°C and a relative humidity of 50% (ISO 23529). The measurement and data processing conditions for determining elongation and stress are as described in standard NF ISO 37:2012-03. The stress is determined for an elongation of 0.1 and the modulus of elasticity under tension at 10% elongation is calculated by taking the ratio of this stress value to the elongation value.A person skilled in the art will know how to choose and adapt the dimensions of the test specimen according to the quantity of composition accessible and available, particularly in the case of specimen sampling from tires.

[0023] The nominal secant modulus at 10% of the inner layer strictly less than the nominal secant modulus at 10% of the corresponding outer layer makes it possible to dilute the stresses generated by the stiffening structure at the point of penetration of the stiffening structure into said inner layer, and thus reduces the initiation of crack at the point of penetration of the stiffening structure into said inner layer.

[0024] Each outer layer, more rigid than the corresponding inner layer, allows the displacements and therefore the forces generated by the stiffening structure to be absorbed by said outer layer concerned, and thus to obtain a more durable anchoring of the stiffening structure.

[0025] This stiffness gradient, induced by the combination of the relatively low stiffness of the inner layer compared to the relatively higher stiffness of the outer layer with which the inner layer is in contact, makes it possible to limit, or even eliminate, the dislodging of the stiffening elements and thus improve the durability of the stiffening structure. Therefore, an anchorage according to the invention is significantly more robust than the bead interfaces described in WO2020 / 128225 and makes it possible to eliminate the failure due to dislodging of the stiffening structure described in WO2022 / 200717.

[0026] An additional advantage of the invention lies in the fact that even when hot, by For example, due to very demanding use of the tire, even if each nominal secant module at 10% elongation decreases, the modulus ratio is maintained strictly above 1.0, which allows the effect of the invention to be maintained even for relatively high temperatures.

[0027] In a preferred embodiment, each first and second inner layer comprises a first and second inner composition respectively, and the first and second inner compositions are identical. Thus, the nominal 10% secant modulus of the first inner layer is equal to the nominal 10% secant modulus of the second inner layer. Alternatively, the first and second inner compositions may be different, and therefore the nominal 10% secant modulus of the first inner layer is different from the nominal 10% secant modulus of the second inner layer.

[0028] Similarly, if each first and second outer layer comprises a first and second outer composition respectively, the first and second outer compositions are identical. Thus, the nominal 10% secant modulus of the first outer layer is equal to the nominal 10% secant modulus of the second outer layer. Alternatively, the first and second outer compositions may be different, and therefore the nominal 10% secant modulus of the first outer layer is different from the nominal 10% secant modulus of the second outer layer.

[0029] Thus, embodiments may exist in which the first modulus ratio is equal to the second modulus ratio. It is also possible to consider embodiments in which the first modulus ratio is strictly greater than the second modulus ratio, which is particularly advantageous when the first sidewall and / or bead is arranged on the same side of the tire's median plane as the outer side of the tire, for the reasons explained above.

[0030] In embodiments, the stiffening structure comprises at least one first stiffening element extending continuously in the toroidal cavity from at least the first flank and / or bead to at least the apex and being anchored in the first flank and / or bead and / or in the apex by extending into the first flank and / or bead and / or the apex, said first stiffening element passing through the first inner layer and penetrating at least partially the first outer layer.

[0031] Optionally, the stiffening structure comprises at least one second stiffening element extending continuously into the toroidal cavity from at least the second flank and / or bead to at least the apex and being anchored in the second flank and / or bead and / or in the apex by extending into the second flank and / or ridge and / or top, said second stiffening element passing through the second inner layer and penetrating at least partially the second outer layer.

[0032] By anchored in a side and / or bead and / or in the top, it is understood that the stiffening structure or the stiffening element penetrates the side and / or bead and / or the top, that is to say that the stiffening structure or the stiffening element passes through the internal surface to anchor itself in a side and / or bead and / or in the top.

[0033] The stiffening structure or stiffening element passes through a layer when it extends through the entire thickness of said layer in contact with said layer. The stiffening structure or stiffening element penetrates at least partially into a layer when it passes through said layer in contact with said layer without necessarily exiting it. Thus, the stiffening structure or stiffening element penetrating a layer may pass through said layer. Alternatively, the stiffening structure or stiffening element penetrating a layer may pass only through a portion of the layer and thus not penetrate it.

[0034] The toroidal inflation cavity is intended to be pressurized by an inflation gas once the tire is mounted on a mounting support, most often a rim.

[0035] Among other advantages, the stiffening structure makes it possible to simultaneously increase the radial stiffness, axial stiffness and drift stiffness of the tire compared to a conventional tire not including a stiffening structure but also compared to tires including other stiffening structures, such as the one described in WO2017 / 005713.

[0036] By increasing radial stiffness, the stiffening structure limits radial deformation of the apex during rolling, and in particular, camber, i.e., radial deformation opposite to the contact patch of the tread surface in contact with the ground. Thus, during tire rotation, the stiffening structure limits the amplitude of cyclic deformations of the tire, and in particular of its tread, and therefore limits the resulting energy dissipation, which contributes to a reduction in rolling resistance. Furthermore, under radial loading, the value of the contact patch with the ground is not modified, which allows the same grip performance to be maintained as for the tire described in WO2017 / 005713.

[0037] By increasing axial and drift stiffness, the stiffening structure will contribute to improved behavior under transverse loading, for example during drifting. Furthermore, under transverse loading, the contact area with the ground ensures a more homogeneous distribution of contact pressures, thereby increasing transverse grip.

[0038] Furthermore, the stiffening structure participates at least partially in bearing the load applied to the tire, such that this applied load is jointly borne by the tire, thanks to its pneumatic and intrinsic structural rigidity, and by the stiffening structure. Thus, when the tire is subjected to a nominal radial load, a portion of the stiffening structure arranged opposite the contact area is placed in tension. In some embodiments, conversely, a portion of the stiffening structure arranged at the contact area is subjected to buckling in compression.

[0039] The presence of the stiffening structure thus makes it possible to reduce the tire's contribution to load-bearing capacity and therefore to reduce its structural rigidity, for example by reducing the volume of the bead. Indeed, the bead of a conventional tire dissipates a significant amount of energy due to their volume and the hysteretic nature of their constituent elastomeric compound. Reducing their volume thus makes it possible to significantly reduce rolling resistance.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] 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.

[0044] 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 ribs and passes through the axial midpoint of the apex reinforcement.

[0045] By circumferential equatorial plane of the tire, denoted E, is meant, in a meridional 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 meridional 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 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.

[0046] By meridian plane, we mean a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0047] 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.

[0048] By bead, we mean the radial 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 enabling its attachment. The bead is therefore delimited radially internally by the inner radial end of the tire and radially externally by an axial line passing through the outermost radial point in contact with a standard rim as defined by the European Tyre and Rim Technical Organisation or "ETRTO" standard, 2023.

[0049] By sidewall, we mean the radial portion of the tire connecting the bead to the crown. The sidewall is radially delimited externally by an edge of the tread. The axial edges of the tread 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 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 an obvious boundary between the tread and the sidewall of the tire, the edges are determined simply. In the case where the tread is continuous with the sidewalls, the edges are usually determined by loading the tire to 80% of its load capacity according to the ETRTO 2023 standard manual, and the edges are identified as the axial limits of the tread in contact with the ground.The sidewall is delimited radially internally by an axial line passing through the outermost radial point in contact with a standard rim as defined by the European Tyre and Rim Technical Organisation or "ETRTO" standard, 2023.

[0050] 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).

[0051] The tires of the invention are preferably intended for passenger vehicles as defined in the European Tyre and Rim Technical Organisation or "ETRTO" standard, 2023. Such a tire has a cross-section in a meridional plane characterized by a section height H and a width of Nominal section SW as defined by the European Tyre and Rim Technical Organisation or "ETRTO" standard, 2023. The SW and H values ​​are indicated on the tire sidewall marking, for example as defined according to the ETRTO manual, 2023.

[0052] Preferably, the passenger vehicle tires to which the invention will advantageously be applied are such that the H / S ratio, expressed as a percentage, is at most 90 and at least 20, and the nominal section width SW is at least 115 mm and at most 385 mm. Furthermore, the hook diameter D, defining the diameter of the tire mounting rim, is at least 12 inches and at most 30 inches.

[0053] Conventionally, in a tire comprising a crown reinforcement and a carcass reinforcement, the crown includes a tread intended to contact the road surface and a crown reinforcement arranged radially within the tread. The carcass reinforcement is anchored in each bead and extends radially in each sidewall and axially in the crown, radially within the crown reinforcement. Conventionally, the crown reinforcement includes at least one crown layer comprising reinforcing elements. These reinforcing elements are preferably textile or metallic wire elements.

[0054] In embodiments enabling the performance of so-called radial tires as defined by ETRTO, the carcass reinforcement comprises at least one carcass layer, said 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 used in at least a portion of the sidewall and strictly less than 80° in at least a portion of the crown.

[0055] In an advantageous embodiment, the stiffening structure is not airtight to the tire inflation gas. Thus, the stiffening structure allows the inflation gas to pass through. In other words, the stiffening structure does not define a secondary pressure cavity in the tire. By "not airtight," it is understood that the stiffening structure is permeable to the inflation gas so that the pressure is homogeneous in the toroidal cavity at all times, and in particular during tire inflation.

[0056] Advantageously, the first modulus ratio is greater than or equal to 2.0, preferably greater than or equal to 3.0.

[0057] Optionally, the second modulus ratio is greater than or equal to 2.0, preferably greater than or equal to 3.0.

[0058] A relatively high modulus ratio makes it possible to further reduce crack initiation at the point of penetration of the stiffening structure into the inner layer concerned and / or to take up more stress in the outer layer concerned.

[0059] Preferably, the first modulus ratio is less than 20.0, preferably less than or equal to 15.0, more preferably less than or equal to 10.0 and even more preferably less than or equal to 7.0.

[0060] Optionally, the second modulus ratio is less than 20.0, preferably less than or equal to 15.0, more preferably less than or equal to 10.0 and even more preferably less than or equal to 7.0.

[0061] An excessively high modulus ratio would mean that, for a given inner layer, the outer layer in question exhibits relatively high rigidity, resulting in high brittleness (or low ductility) of the outer layer. This creates a risk of breakage of the outer layer, particularly due to the stresses on the stiffening structure during entry into the contact area, during passage through the contact area (especially during drifting), during exit from the contact area, and during the passage of the portion of the tire containing the stiffening structure to the opposite side of the contact area.

[0062] Advantageously, the nominal secant modulus at 10% elongation of the first outer layer is greater than or equal to 5 MPa.

[0063] Optionally, the nominal secant modulus at 10% elongation of the second outer layer is greater than or equal to 5 MPa.

[0064] Advantageously, the nominal secant modulus at 10% elongation of the first outer layer is less than or equal to 60 MPa, preferably less than or equal to 20 MPa.

[0065] Optionally, the nominal secant modulus at 10% elongation of the second outer layer is less than or equal to 60 MPa, preferably less than or equal to 20 MPa.

[0066] In particularly preferred embodiments, the modulus at 10% extension of the first inner layer is less than or equal to 8 MPa, preferably less than or equal to 5 MPa.

[0067] In particularly preferred embodiments, the modulus at 10% extension of the second inner layer is less than or equal to 8 MPa, preferably less than or equal to 5 MPa.

[0068] Such rigidity is relatively low and allows the stresses induced by the stiffening structure to be absorbed on the inner layer concerned. Thus, the endurance of the stiffening structure is improved.

[0069] Advantageously, the nominal secant modulus at 10% elongation of the first and / or second inner layer can be greater than or equal to 1 MPa.

[0070] Advantageously, the thickness of the first and / or second inner layer may be greater than or equal to 0.1 mm and / or less than or equal to 5 mm, preferably greater than or equal to 0.1 mm and / or less than or equal to 2 mm.

[0071] Advantageously, the thickness of the first and / or second outer layer can be greater than or equal to 2 mm and / or less than or equal to 10 mm.

[0072] Such thicknesses of the inner and outer layers allow for the absorption of deformations and the resisting of stresses exerted by the stiffening structure in the outer and inner layers. Those skilled in the art will be able to determine the optimal thicknesses of each of the inner and outer layers, taking into account, in particular, the stiffness of each of these layers.

[0073] In a first design, the first inner layer forms at least in part the inner surface, said stiffening structure penetrating the first inner layer at a first radially internal and / or external anchorage point of the first inner layer arranged in the first flank and / or bead and / or the top.

[0074] In embodiments using a first stiffening element, said first stiffening element penetrates the first inner layer at the first radially internal and / or external anchoring point of the first inner layer arranged in the first flank and / or bead and / or the top.

[0075] Optionally, in this first design, the second inner layer forms at least part of the inner surface, said stiffening structure penetrating the second inner layer at a second radially internal and / or external anchorage point of the second inner layer arranged in the second flank and / or bead and / or the top.

[0076] In embodiments using a second stiffening element, said second stiffening element penetrates the second inner layer at the second radially internal and / or external anchoring point of the second inner layer arranged in the second flank and / or bead and / or the top.

[0077] According to the first design, each first and / or second inner layer is in contact at least locally with said stiffening structure respectively at the first and / or second radially internal and / or external anchoring point.

[0078] In embodiments using first and / or second stiffening elements, each first and / or second inner layer is in contact at least locally respectively with said first and / or second stiffening element at the first and / or second radially internal and / or external anchoring point.

[0079] In a first variant, the entirety of the first inner layer forms at least part of the inner surface.

[0080] Optionally, the entire second inner layer forms at least part of the inner surface.

[0081] Thus, no layer covers the first and / or second inner layer which is entirely in contact with the inflation gas when the tire is inflated.

[0082] In a first configuration of this first variant, the first and / or second inner layer is a sealing layer for at least one blowing gas. Optionally, the sealing layer of the first and / or second inner layer comprises a sealing composition including one or more butyl rubbers. More preferably, the sealing composition of the first and / or second inner layer comprises at least 50 parts per cent of the butyl rubber(s).

[0083] The layer is called a sealing layer because of its low permeability to the tire inflation gas. Such a sealing layer is such that a tire without the sealing layer exhibits higher permeability compared to a tire with the sealing layer.

[0084] The term "part per percent of elastomer" or "pce" means the part by weight of a constituent per 100 parts by weight of the elastomer(s), i.e., of the total weight of the elastomer(s). Thus, a constituent at 60 pce would mean, for example, 60 g of that constituent per 100 g of elastomer. In this application, the terms "elastomer" and "rubber" are used interchangeably throughout the text.

[0085] Butyl rubber means an isobutylene homopolymer or an isobutylene-isoprene copolymer, as well as halogenated derivatives, in particular generally brominated or chlorinated, of these isobutylene homopolymers and isobutylene-isoprene copolymers. Preferably, the butyl rubber(s) usable in the composition are chosen from isobutylene rubbers, isobutylene-isoprene copolymers (IIR), bromobutyl rubbers such as bromoisobutylene-isoprene copolymer (BIIR), and chlorobutyl rubbers such as chloroisobutylene-isoprene copolymer (CIIR). By extension of the previous definition, we will also include under the name "butyl rubber" copolymers of isobutylene and styrene derivatives such as isobutylene and brominated methylstyrene copolymers (BIMS), which notably includes the elastomer called EXXPRO® marketed by the company Exxon.

[0086] Other elastomers present in the sealing composition in addition to the butyl rubber(s) include, in particular, diene elastomers other than the butyl elastomers mentioned above. The term "diene elastomer" or "diene rubber" should be understood, in a known manner, to mean one or more elastomers derived at least in part (i.e., a homopolymer or a copolymer) from diene monomers. (monomers bearing two carbon-carbon double bonds, conjugated or not). Such diene elastomers are known to those skilled in the art and, for example, described in WO2016 / 001226A1.

[0087] In a second configuration of this first variant, the first and / or second inner layer is not a sealing layer for at least one inflation gas. In this second configuration, the tire's sealing performance is reduced, which, for certain sporting uses, does not negatively impact the tire's operation given its relatively short lifespan. Nevertheless, this avoids weakening the anchoring of the stiffening structure at the first and / or second radially internal and / or external anchoring point.

[0088] In this second configuration, the first and / or second inner layer comprises an elastomeric composition containing less than 50 parts per million (ppm) of butyl rubber, preferably less than 10 parts per million (ppm) of butyl rubber, and is more preferably substantially free of butyl rubber. Preferably, the elastomeric composition of each first and / or second inner layer comprises at least 50 parts per million (ppm) of a diene elastomer. The elastomeric composition is called elastomeric because it is based on an elastomeric composition; this elastomeric composition may comprise one or more elastomers, as well as fillers and other components commonly used in tire compounds. This reduces the risk of poor adhesion between the stiffening structure and the inner layer in question.Indeed, butyl rubber exhibits relatively weak adhesion to the stiffening structure, which creates a unique zone in the tire that is conducive to the initiation of cracks at the anchoring point in the sidewall and / or bead and / or crown.

[0089] In a second variant of the first design, the tire comprises a first complementary inner layer forming at least part of the first sidewall and / or bead and / or the top and arranged radially and / or axially inside the first inner layer, the first complementary inner layer forming at least part of the inner surface, the first complementary inner layer is arranged at a distance from said first anchor point radially inside and / or outside the stiffening structure.

[0090] In embodiments using a first stiffening element, the first complementary inner layer is arranged at a distance from said first radially internal and / or external anchoring point of the first stiffening element.

[0091] Optionally, the tire comprises a second complementary inner layer forming at least part of the first sidewall and / or bead and / or crown and arranged radially and / or axially within the second inner layer, the second complementary inner layer forming at least part of the surface internally, the second complementary inner layer is arranged at a distance from said first radially internal and / or external anchoring point of the stiffening structure.

[0092] In embodiments using a second stiffening element, the second complementary inner layer is arranged at a distance from said second radially internal and / or external anchoring point of the second stiffening element.

[0093] By distance, it is understood that the sealing layer is not in contact with the stiffening structure or the stiffening element at the anchor point concerned. The minimum distance between the sealing layer and the anchor point concerned is determined by a person skilled in the art based on their knowledge of the tire manufacturing process and also on the required sealing performance.

[0094] Preferably, the minimum distance between the sealing layer and said first and / or second radially internal and / or external anchor point is greater than or equal to 1 mm, preferably 5 mm.

[0095] In this second variant of the first design, the stiffening structure or the stiffening element concerned does not cross or penetrate the corresponding inner complementary layer.

[0096] Preferably, the first and / or second complementary inner layer is respectively in contact with the first and / or second inner layer.

[0097] Advantageously, the first and / or second complementary inner layer is a sealing layer for at least one blowing gas.

[0098] Since the sealing layer is arranged at a distance from the radially internal and / or external anchoring point, the latter ensures the sealing function without weakening the anchoring of the stiffening structure to the radially internal and / or external anchoring point, whether due to high rigidity of the sealing layer or due to poor adhesion of the stiffening structure or stiffening element to the sealing layer.

[0099] Optionally, the sealing layer includes a sealing composition comprising one or more butyl rubbers.

[0100] More preferably, the sealing composition comprises at least 50 parts per cent of the butyl rubber(s). Thus, the butyl rubber(s) usable in the composition represent at least 50 parts per cent, that is to say, they represent at least 50% by weight of the total weight of the elastomer(s).

[0101] In a second design, the tire comprises a first complementary inner layer forming at least part of the first sidewall and / or bead and / or crown and arranged radially and / or axially inside the first inner layer, the first inner complementary layer forming at least in part the inner surface, said stiffening structure passing through the first inner complementary layer and penetrating the first inner complementary layer at a first radially internal and / or external anchorage point of the first inner complementary layer arranged in the first flank and / or bead and / or the top.

[0102] In embodiments using a first stiffening element, said first stiffening element passes through the first inner complementary layer and penetrates the first inner complementary layer at the first radially inner and / or outer anchorage point of the first inner complementary layer arranged in the first flank and / or bead and / or the top.

[0103] Optionally, the tire includes a second complementary inner layer forming at least part of the second sidewall and / or bead and / or the crown and arranged radially and / or axially inside the second inner layer, the second complementary inner layer forming at least part of the inner surface, said stiffening structure passing through the second complementary inner layer and penetrating the second complementary inner layer at a second radially internal and / or external anchoring point of the second complementary inner layer arranged in the second sidewall and / or bead and / or the crown.

[0104] In embodiments using a second stiffening element, said second stiffening element passes through the second inner complementary layer and penetrates the second inner complementary layer at the second radially internal and / or external anchoring point of the second inner complementary layer arranged in the second flank and / or bead and / or the top.

[0105] According to the second design, each first and / or second complementary inner layer is in contact at least locally with said stiffening structure respectively at the first and / or second radially inner and / or outer anchoring point.

[0106] In embodiments using first and / or second stiffening elements, each first and / or second complementary inner layer is in contact at least locally respectively with said first and / or second stiffening element at the first and / or second radially inner and / or outer anchoring point.

[0107] In a first embodiment, the first and / or second inner supplementary layer is a sealing layer for at least one blowing gas. Optionally, the sealing layer of the first and / or second inner supplementary layer comprises a sealing composition including one or more butyl rubbers. More preferably, the sealing composition of the first and / or second complementary inner layer comprises at least 50 pieces of butyl rubber(s).

[0108] In a second embodiment, the first and / or second inner supplementary layer is a layer that is not a sealing layer for at least one inflation gas. Preferably, in this second embodiment, the first and / or second inner supplementary layer comprises an elastomeric composition containing less than 50 parts per annum of butyl rubber, preferably less than 10 parts per annum of butyl rubber, and is more preferably substantially free of butyl rubber. Preferably, the elastomeric composition of each first and / or second inner layer comprises at least 50 parts per annum of a diene elastomer. The elastomeric composition is called elastomeric because it is based on an elastomeric composition; this elastomeric composition may comprise one or more elastomers, as well as fillers and other components commonly used in the field of tire compositions.Thus, as explained previously, the risk of poor adhesion between the stiffening structure and the inner layer in question is reduced.

[0109] Regardless of the variant, preferably, a complementary modulus ratio between a nominal secant modulus at 10% elongation of the first inner layer and a nominal secant modulus at 10% elongation of the first complementary inner layer is strictly greater than 1.0, preferably greater than or equal to 2.0.

[0110] Optionally, a complementary modulus ratio between a nominal secant modulus at 10% elongation of the second inner layer and a nominal secant modulus at 10% elongation of the second complementary inner layer is strictly greater than 1.0, preferably greater than or equal to 2.0.

[0111] Thus, the same stiffness gradient mechanism described previously with reference to the inner and outer layers is applied to the complementary inner and inner layers.

[0112] Nevertheless, one can imagine a complementary modulus ratio between a nominal secant modulus at 10% elongation of the first and / or second inner layer and a nominal secant modulus at 10% elongation of the first and / or second complementary inner layer less than or equal to 1.0. Indeed, even if a crack initiation appears at the point of penetration of the stiffening structure or stiffening element into the relevant complementary inner layer, the modulus ratio of the invention will prevent the propagation of the crack in the inner and outer layers.

[0113] In one embodiment, the pneumatic component includes a first anchoring element arranged in the toroidal cavity and extending projecting from the first flank and / or ridge towards the inside of the toric cavity and / or from the apex towards the inside of the toric cavity, being in contact at least locally with said stiffening structure.

[0114] In embodiments using a first stiffening element, the first anchoring member extends in projection from the first flank and / or bead towards the inside of the toroidal cavity and / or from the apex towards the inside of the toroidal cavity, being in contact at least locally with said first stiffening element.

[0115] Optionally, the pneumatic includes a second anchoring member arranged in the toroidal cavity and extending in projection from the second flank and / or bead towards the interior of the toroidal cavity and / or from the apex towards the interior of the toroidal cavity, being in contact at least locally with said stiffening structure.

[0116] In embodiments using a second stiffening element, the second anchoring member extends in projection from the second flank and / or bead towards the interior of the toroidal cavity and / or from the apex towards the interior of the toroidal cavity, being in contact at least locally with said second stiffening element.

[0117] Preferably, said first anchoring member is made of material with at least the first flank and / or ridge and / or with the apex.

[0118] Preferably, said second anchoring member is made of material with at least the second flank and / or bead and / or with the apex.

[0119] By "coming from the material," it is understood that the corresponding anchoring element is not attached subsequently to the tire's cross-linking, for example by bonding after the tire's cross-linking. Thus, the corresponding anchoring element is cross-linked simultaneously with the first or second sidewall and / or bead and / or with the top.

[0120] According to the first design described above, the first inner layer forms at least a part of said first anchoring member. In other words, at least a part of said first member is made of material along with the first inner layer.

[0121] Optionally, the second inner layer forms at least part of said second anchoring member. In other words, at least part of said second member is made of material along with the second inner layer.

[0122] Such anchoring devices make it possible to reinforce the interface between the stiffening structure and the internal surface and to limit interface failure resulting from repeated stresses exerted by the stiffening structure on the interface. This improves the endurance of the stiffening structure. Indeed, such anchoring of the stiffening structure makes it possible to distribute the stresses in the anchoring device and therefore to obtain an anchoring whose robustness is improved.

[0123] In the first design described above, the first and / or second inner layer respectively forms the entirety of the first and / or second anchoring member. In other words, the entirety of each first and / or second member is formed from the material of the first and / or second inner layer respectively.

[0124] In other variations of the first design, said first and / or second anchoring element comprises a skin formed respectively by the first and / or second inner layer and a core formed respectively by the first and / or second outer layer. In other words, a skin of each first and / or second element is formed respectively from the material of the first and / or second inner layer, and a core of each first and / or second element is formed respectively from the material of the first and / or second outer layer.

[0125] In the second design described above, the first and / or second inner complementary layer forms the entirety of the first and / or second anchoring member, respectively. In other words, the entirety of each first and / or second member is formed from the material of the first and / or second inner complementary layer, respectively.

[0126] In other variations of the second design, said first and / or second anchoring element comprises a skin formed respectively by the first and / or second inner complementary layer and a core formed respectively by the first and / or second inner layer. In other words, a skin of each first and / or second element is formed respectively by the first and / or second inner complementary layer, and a core of each first and / or second element is formed respectively by the first and / or second inner layer.

[0127] In embodiments, the tire comprises a first complementary outer layer forming at least part of the first sidewall and / or bead and / or the top and arranged radially and / or axially outside the first outer layer, said stiffening structure passing through the first outer layer and penetrating at least part of the first complementary outer layer.

[0128] In embodiments using a first stiffening element, said first stiffening element passes through the first outer layer and penetrates at least partially the first complementary outer layer.

[0129] Optionally, the tire comprises a second complementary outer layer forming at least part of the second sidewall and / or bead and / or crown and arranged radially and / or axially outside the second outer layer, said stiffening structure passing through the second outer layer and penetrating at least partially the second complementary outer layer.

[0130] In embodiments using a second stiffening element, said second stiffening element passes through the second outer layer and penetrates at least partially the second complementary outer layer.

[0131] Preferably, the first and / or second complementary outer layer is in contact respectively with the first and / or second outer layer.

[0132] In advantageous embodiments, a first complementary modulus ratio between a nominal secant modulus at 10% elongation of the first outer complementary layer and a nominal secant modulus at 10% elongation of the first outer layer is strictly greater than 1.0, preferably greater than or equal to 2.0.

[0133] Optionally, a second complementary modulus ratio between a nominal secant modulus at 10% elongation of the second outer complementary layer and a nominal secant modulus at 10% elongation of the second outer layer is strictly greater than 1.0, preferably greater than or equal to 2.0.

[0134] Thus, the same stiffness gradient mechanism described previously with reference to the first and / or second inner and outer layers is applied to the first and / or second outer and complementary outer layers.

[0135] Nevertheless, it is entirely possible to imagine a complementary modulus ratio between a nominal secant modulus at 10% elongation of the first and / or second outer complementary layer and a nominal secant modulus at 10% elongation of the first and / or second outer layer less than or equal to 1.0. Indeed, since the forces are taken up by the first and / or second outer layer, the first and / or second outer complementary layer does not necessarily need to have a high rigidity.

[0136] Advantageously, said stiffening structure or said first stiffening element comprises a portion extending continuously into the toroidal cavity from the first radially internal anchor point and the first radially external anchor point.

[0137] Advantageously, said stiffening structure or said first stiffening element comprises a radially internal anchoring portion of said stiffening structure or said first stiffening element extending from the first radially internal anchoring point in the first flank and / or bead and extending the portion extending continuously into the toroidal cavity.

[0138] Advantageously, said stiffening structure or said first stiffening element comprises a radially external anchorage portion of said stiffening structure or said first stiffening element extending from the first radially external anchorage point in the apex and extending the portion extending continuously into the toric cavity.

[0139] Optionally, said stiffening structure or said second stiffening element includes a portion extending continuously into the toric cavity from the second radially internal anchor point and the second radially external anchor point.

[0140] Optionally, said stiffening structure or said second stiffening element includes a radially internal anchoring portion of said stiffening structure or said second stiffening element extending from the second radially internal anchoring point in the second flank and / or bead and extending the portion extending continuously into the toroidal cavity.

[0141] Optionally, said stiffening structure or said second stiffening element includes a radially external anchoring portion of said stiffening structure or said second stiffening element extending from the second radially external anchoring point in the apex and extending the portion extending continuously into the toroidal cavity.

[0142] In embodiments, at least a portion of said stiffening structure or of said first stiffening element and / or of said second stiffening element is coated with at least one layer of a polymeric composition, preferably an adhesive composition.

[0143] Such a layer of polymeric composition limits the propagation of air and any corrosive agents along the stiffening structure or stiffening element, and therefore within the tire structure. The composition is called polymeric because it is based on a polymeric composition; this polymeric composition may comprise one or more polymers, for example, chosen from thermoplastic polymers, thermosetting and / or crosslinkable polymers, elastomers, thermoplastic elastomers, as well as fillers and other components commonly used in tire compounds.

[0144] In some embodiments, the adhesive composition comprises a resin selected from aldehyde / phenol resins, polyepoxide resins, polyisocyanate resins, aromatic polyepoxy-phenolic resins, and multifunctional resins, as well as mixtures of these resins. In addition to limiting the spread of air and any corrosive agents, the adhesive composition improves the anchoring of the stiffening elements within the tire structure.

[0145] In embodiments, said portion extending continuously in the toroidal cavity of said stiffening structure or of the or each first stiffening element and / or of the or each second stiffening element may be coated at least in part with the polymeric composition.

[0146] The polymeric composition here makes it possible to limit the propagation of air and any corrosive agents.

[0147] In embodiments, said radially inner anchoring portion of said stiffening structure or of the or each first stiffening element and / or of the or each second stiffening element may be coated at least in part with the polymer composition.

[0148] The polymer composition here makes it possible to improve the anchoring of the stiffening structure in the first flank and / or bead and / or second flank and / or bead.

[0149] In embodiments, said radially external anchoring portion of said stiffening structure or of the or each first stiffening element and / or of the or each second stiffening element may be coated at least in part with the polymer composition.

[0150] The polymer composition here makes it possible to improve the anchoring of the stiffening elements in the apex.

[0151] Advantageously, said first radially internal anchorage point of said first stiffening element and said first radially external anchorage point of said first stiffening element are arranged on the same side of the median plane of the tire.

[0152] Optionally, said second radially internal anchor point of said second stiffening element and said second radially external anchor point of said second stiffening element are arranged on the same other side of the median plane of the tire.

[0153] Thus, the portions extending, on the one hand, between an inner radial anchor point and an outer radial anchor point located on the same side of the median plane, and on the other hand, between an inner radial anchor point and an outer radial anchor point located on the opposite side of the median plane, do not intersect. This limits the axial buckling of the tread, i.e., the axial compression of the tread, particularly under conditions of high lateral stress. In this way, on the one hand, a regular contact area is maintained, and on the other hand, the risk of damage to the crown reinforcement of the tire is reduced, notably by preventing compression of the various constituent elements of the crown reinforcement, for example, the textile and metallic wire reinforcement elements of the crown reinforcement.

[0154] Preferably, the stiffening structure comprises a plurality of first stiffening elements distributed circumferentially in the toric cavity.

[0155] Optionally, the stiffening structure includes a plurality of second stiffening elements distributed circumferentially in the toric cavity.

[0156] In a first configuration of the stiffening elements, each first The stiffening element forms a first continuous stiffening element that meanders at least from the first flank and / or bead through the apex. Preferably, each second stiffening element also forms a second continuous stiffening element that meanders at least from the second flank and / or bead through the apex.

[0157] Thus, tire manufacturing is facilitated and the robustness of the stiffening structure is improved by eliminating the ends of said stiffening element that are anchored in each sidewall and / or bead and / or in the crown. In this first configuration, it is therefore possible to have a continuous stiffening element extending over the entire circumference of the tire. Since said stiffening element of the stiffening structure is continuous, the transmission of forces between each sidewall and / or bead is improved, as the forces are distributed over the tire. Thus, the stiffening structure performs its function over the entire circumference of the tire.

[0158] According to a first variant of the first configuration of the stiffening elements, said first and second stiffening elements form a continuous stiffening element which extends continuously from the first flank and / or bead to the second flank and / or bead via the top so as to meander from the first flank and / or bead to the second flank and / or bead.

[0159] According to a second variant of the first configuration of the stiffening elements, each first stiffening element forms a continuous stiffening element that meanders between the first flank and / or bead and the apex. Also in this second variant, each second stiffening element forms a continuous stiffening element that meanders between the second flank and / or bead and the apex.

[0160] In a second configuration of the stiffening elements, it may be envisaged that each first stiffening element extends from the first flank and / or bead to the apex and has one end in the first flank and / or bead. Similarly, it may be envisaged that each second stiffening element extends from the second flank and / or bead to the apex and has one end in the second flank and / or bead.

[0161] In a first variant of this second configuration, it may be envisaged that each first stiffening element extends from the first side and / or bead to the apex and has one end at the apex. Similarly, it may be envisaged that each second stiffening element extends from the second side and / or bead to the apex and has one end at the apex.

[0162] In a second variant of this second configuration, each first stiffening element is respectively every second stiffening element and extends from the first flank and / or bead to the second flank and / or bead via the top and has an end in each first and second flank and / or bead.

[0163] Each stiffening element according to one of the designs or configurations defined above can be characterized geometrically, in particular by its average cross-section Sm, this characteristic not necessarily being identical for all the stiffening elements. The average cross-section Sm is the average of the cross-sections obtained by cutting the stiffening element through all cylindrical surfaces coaxial with the tire and radially contained within the inner toroidal cavity. In the most frequent case of a constant cross-section, the average cross-section Sm is the constant cross-section of the stiffening element. The average cross-section Sm comprises a larger characteristic dimension Dmax and a smaller characteristic dimension Dmin, the ratio of which R = Dmax / Dmin is called the aspect ratio.For example, a stiffening element having a circular mean cross-section Sm, with a diameter equal to d, has a form ratio R=l, a stiffening element having a rectangular mean cross-section Sm, with a length L and a width 1, has a form ratio R=L / 1, and a stiffening element having an elliptical mean cross-section Sm, with a major axis D and a minor axis d, has a form ratio R=D / d.

[0164] A first preferred type of stiffening element, with a form ratio R of at most 3, is called one-dimensional. In other words, a stiffening element is considered one-dimensional when the largest characteristic dimension Dmax of its average cross-section Sm is at most 3 times the smallest characteristic dimension Dmin of its average cross-section Sm. A one-dimensional stiffening element has a wire-like mechanical behavior, that is, it can only be subjected to tensile or compressive forces along its neutral axis. This is why a one-dimensional stiffening element is usually called a wire-like stiffening element.Among the components commonly used in the field of pneumatics, textile filament elements, consisting of an assembly of elementary textile monofilaments, or metal cables, consisting of an assembly of elementary metal monofilaments, can be considered as one-dimensional stiffening elements, because their average cross-section Sm being substantially circular, the shape ratio R is equal to 1, therefore less than 3.

[0165] A second type of stiffening element, with a form ratio R of at least 3, is said to be two-dimensional. In other words, a stiffening element is considered two-dimensional when the largest characteristic dimension Dmax of its average cross-section Sm is at least equal to 3 times the smallest characteristic dimension Dmin of its average cross-section Sm. A two-dimensional stiffening element has membrane-like mechanical behavior, meaning that it can only be subjected to tensile or compressive forces within its thickness, defined by the smallest characteristic dimension Dmin of its average cross-section Sm. According to one variant, a stiffening element with an aspect ratio R of at least 3 and at most 50 is called a two-dimensional strip-type element. According to a second variant, a stiffening element with an aspect ratio R of at least 50 is called a two-dimensional film-type element.

[0166] The materials that can be used for each stiffening element are as described in WO2022 / 200717.

[0167] In a highly advantageous embodiment, the first and / or second stiffening element(s) are respectively a first and / or second wire stiffening element, preferably a first and / or second textile wire stiffening element. Preferably, the wire stiffening elements are identical, that is, they have identical geometric characteristics and constituent materials.

[0168] These wire stiffening elements are commonly called stays. The advantage of using wire stiffening elements is that they result in a stiffening structure with low mass and minimal hysteresis. Using identical wire stiffening elements ensures a homogeneous distribution of forces among the stiffening elements.

[0169] By textile, it is understood that each wire stiffening element is non-metallic, for example made of a material selected from polyester, polyamide, polyketone, polyvinyl alcohol, cellulose, mineral fiber, natural fiber, elastomeric material, or a mixture of these materials. Examples of polyesters include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PBT (polybutylene terephthalate), PBN (polybutylene naphthalate), PPT (polypropylene terephthalate), and PPN (polypropylene naphthalate). Examples of polyamides include aliphatic polyamides such as polyamides 4-6, 6, 6-6 (nylon), 11, or 12, and aromatic polyamides such as aramid. Preferably, the material is a polyester or an aliphatic polyamide.

[0170] Advantageously, in an embodiment for manufacturing the tire using a relatively simple process, each wire stiffening element extends within the toroidal cavity along a principal direction forming an angle with the circumferential direction of the tire ranging, in absolute value, from 85° to 90°. In another embodiment for manufacturing the tire using a more complex process but allowing for increased circumferential stiffness rential, each wire stiffening element extends in the toroidal cavity along a principal direction forming, with the circumferential direction of the tire, an angle ranging, in absolute value, from 45° to 85° as explained in particular in WO2020 / 128225.

[0171] Preferably, the stiffening structure or said first stiffening element extending from the first flank and / or bead to the apex, or said radially inner anchoring portion of said first stiffening element, is anchored in the first flank and / or bead by being anchored in or around a first radially inner reinforcement structure of the stiffening structure arranged in the first flank and / or bead. Also preferably, the stiffening structure or said first stiffening element extending from the first flank and / or bead to the apex, or said radially outer anchoring portion of said first stiffening element, is anchored in the apex by being anchored in or around one or more radially outer reinforcement structures of the stiffening structure arranged in the apex.

[0172] Advantageously, the first radially inner reinforcing structure is arranged in the first outer layer or the complementary outer layer.

[0173] Advantageously, the first radially external reinforcing structure is arranged in the first inner layer. Indeed, given the inclination of the stiffening structure, the forces exerted at the top by the stiffening structure on the anchorage include high shear and low tensile forces, unlike the forces exerted in the flank and / or the flange, which include low shear and high tensile forces. It is thus possible to anchor the stiffening structure in the least rigid layer, which has sufficient stiffness to resist the low tensile forces.

[0174] Alternatively, the first radially external reinforcing structure is arranged in the first outer layer or the first complementary outer layer.

[0175] Alternatively, the stiffening structure or said first stiffening element extending from the first flank and / or bead to the apex, or said radially inner anchoring portion of said first stiffening element, is anchored in the first flank and / or bead by being anchored in an elastomeric mass of said first flank and / or bead. Also alternatively, the stiffening structure or said first stiffening element extending from the first flank and / or bead to the apex, or said radially outer anchoring portion of said first stiffening element, is anchored in the apex by being anchored in an elastomeric mass of said apex.

[0176] Optionally, the stiffening structure or said second stiffening element extending from the second flank and / or bead to the top or said The radially inner anchorage portion of said second stiffening element is anchored in the second flank and / or bead by being anchored in or around a second radially inner reinforcement structure of the stiffening structure arranged in the second flank and / or bead. Optionally, the stiffening structure or said second stiffening element extending from the second flank and / or bead to the apex, or said radially outer anchorage portion of said second stiffening element, is anchored in the apex by being anchored in or around one or more radially outer reinforcement structures of the stiffening structure arranged in the apex.

[0177] Advantageously, the second radially inner reinforcement structure is arranged in the second outer layer or the complementary outer layer.

[0178] Advantageously, the second radially external reinforcement structure is arranged in the second inner layer for reasons analogous to those described for the first radially external reinforcement structure.

[0179] Alternatively, the second radially external reinforcement structure is arranged in the second outer layer or the second complementary outer layer.

[0180] Alternatively, the stiffening structure or said second stiffening element extending from the second flank and / or bead to the apex, or said radially inner anchoring portion of said second stiffening element, is anchored in the second flank and / or bead by being anchored in an elastomeric mass of said second flank and / or bead. Also alternatively, the stiffening structure or said second stiffening element extending from the second flank and / or bead to the apex, or said radially outer anchoring portion of said second stiffening element, is anchored in the apex by being anchored in an elastomeric mass of said apex.

[0181] Of course, the tire can include both the first and second radially inner reinforcement structures and the radially outer reinforcement structure(s), or only the first and second radially inner reinforcement structures, or only the radially outer reinforcement structure(s).

[0182] Each radially internal or external reinforcing structure is respectively arranged in the corresponding side and / or bead or in the top, that is to say, arranged radially within the internal surface and embedded in the mass of materials constituting the corresponding side and / or bead or the top. The stiffening structure passes through the internal surface to be anchored in or around the corresponding radially internal reinforcing structure and / or through the internal surface to be anchored in or around the one or more of the radially external reinforcing structure(s).

[0183] As previously stated, the stiffening structure can be anchored in or around at least one radially internal and / or external reinforcing structure.

[0184] Thus, in a first variant, the stiffening structure can be anchored in the very structure of said reinforcement structure, that is to say that the stiffening structure penetrates at least in part into said reinforcement structure, or even crosses it totally so that said reinforcement structure forms a mechanical anchor of the stiffening structure.

[0185] In particular, where said reinforcement structure is an assembly of several wire elements, the stiffening structure is "anchored in the structure" means, for example, that the stiffening structure wraps around certain wire elements of said reinforcement structure so as to pass through it.

[0186] In a second variant, the stiffening structure can be anchored around the very structure of said reinforcement structure, that is to say that the stiffening structure rests on said reinforcement structure so that said reinforcement structure takes up part of the forces exerted on the stiffening structure and anchors the stiffening structure in the side and / or the bulge or the top.

[0187] In particular, where said reinforcement structure is an assembly of several wire elements, the stiffening structure is "anchored around the structure" means, for example, that the stiffening structure wraps around the peripheral wire elements of said reinforcement structure without passing through it.

[0188] In embodiments comprising a first radially internal reinforcing structure arranged in the first flank and / or bead, this preferably includes at least one first circumferential radially internal reinforcing element allowing the anchoring of the stiffening structure.

[0189] In embodiments comprising a second radially internal reinforcing structure arranged in the second flank and / or bead, this preferably includes at least one second circumferential radially internal reinforcing element allowing the anchoring of the stiffening structure.

[0190] In a preferred embodiment, each first and second bead comprises respectively a first and second circumferential radially internal reinforcement element intended to allow the tire to be attached to a tire mounting support, said first circumferential radially internal reinforcement element or each first and second circumferential radially internal reinforcement element being arranged radially outside each first and second circumferential reinforcement element intended to allow the tire to be attached to a tire mounting support.

[0191] Thus, the propagation of noise generated by the stiffening structure from the stiffening structure to the vehicle through the mounting support is reduced. of the tire. Indeed, the noise generated by the stiffening structure is dampened by the tire structure separating the internal radial circumferential reinforcement element considered from the internal radial circumferential reinforcement element intended to allow the tire to be attached to a tire mounting support located on the same side of the tire's median plane.

[0192] This damping is the result of the fact that the circumferential radially internal reinforcement element considered is mechanically decoupled from said circumferential radially internal reinforcement element intended to allow the tire to be attached to a tire mounting support located on the same side of the median plane of the tire.

[0193] Alternatively, said first internal radially reinforcing circumferential element or each first and second internal radially reinforcing circumferential element is intended to allow the tire to be attached to a tire mounting support.

[0194] In one embodiment, said first internal radially reinforcing circumferential element or each first and second internal radially reinforcing circumferential element is a wire reinforcing element extending along a principal direction forming with the circumferential direction of the tire an angle less than or equal to 10°, preferably less than or equal to 5° and more preferably substantially zero.

[0195] In embodiments comprising at least one radially external reinforcing structure arranged in the top, this preferably comprises at least one circumferential radially external reinforcing element.

[0196] In one embodiment, said radially external circumferential reinforcement element of the or each radially external reinforcement structure is a wire reinforcement element extending along a principal direction forming with the circumferential direction of the tire an angle less than or equal to 10°, preferably less than or equal to 5° and more preferably substantially zero.

[0197] In certain embodiments, the tire comprises first and second radially external reinforcement structures. In these embodiments, preferably, each first and second radially external reinforcement structure comprises respectively a first and second circumferential radially external reinforcement element, the first circumferential radially external reinforcement element being arranged at an axial distance from said second circumferential radially external reinforcement element.

[0198] This makes it possible to reduce the mass of the reinforcing structure allowing the anchoring of the stiffening structure in the top and to limit the over-fretching of the top thus allowing to maintain a regular contact area.

[0199] Preferably, the first radially external circumferential reinforcement element and the second radially external circumferential reinforcement element are arranged on either side of the median plane of the tire.

[0200] Thus, the axial distribution of the forces exerted by the stiffening structure on the summit is improved.

[0201] Each internal radially internal circumferential reinforcing element and each external radially external circumferential reinforcing element may be wound in various ways as described in particular in WO2022 / 200717.

[0202] Of course, the tire may include several of the said first and / or second radially internal and / or external reinforcement structures. Brief description of the drawings

[0203] The present invention will be better understood upon study of the detailed description of embodiments, taken by way of non-limiting examples and illustrated by the accompanying drawings in which:

[0204] [Fig. 1] is a view of a tire in a meridian cutting plane parallel to the axis of rotation according to a first embodiment of the invention;

[0205] [Fig.2] is a view analogous to that of [Fig.1] of a tire according to a second example of the realization of the invention;

[0206] [Fig.3] is a schematic perspective view of the inside of the tire of the [Fig. 2]; and

[0207] [Fig.4] is a view analogous to that of [Fig.1] of a tire according to a third example of the realization of the invention. Detailed description

[0208] 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.

[0209] The figures represent a tire 10 having 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 a size of 275 / 35ZR19. In the various figures, the tire 10 is shown in its new condition, i.e., not yet having been driven on.

[0210] The tire 10 includes a crown 12 comprising a tread 14 intended to come into contact with a ground during rolling and a crown reinforcement 16 extending into the crown 12 in the circumferential direction X.

[0211] The tire 10 further comprises a top reinforcement identical to that described WO2022 / 200717 comprising a working reinforcement 20 comprising working layers 24, 26 and a shrink-fit reinforcement 22 comprising a layer 28.

[0212] The tire 10 comprises first and second sidewalls 30A, 30B extending radially inward from the apex 12. The second sidewall 30B is opposite the first sidewall 30A with respect to the median plane M. The tire 10 further comprises first and second bead 32A, 32B extending each first and second sidewall 30A, 30B radially inward, respectively. The second bead 32B is opposite the first bead 32A with respect to the median plane M. Each first and second sidewall 30A, 30B connects each first and second bead 32A, 32B, respectively, to the apex 12.

[0213] The tire 10 comprises first and second outer layers 33A, 33B forming in part each first and second sidewall 30A, 30B and each first and second bead 32A, 32B. Each first and second outer layer 33A, 33B comprises an elastomeric composition not having a sealing function. The elastomeric composition of each first and second outer layer 33A, 33B comprises less than 50 parts per annum of butyl rubber, preferably less than 10 parts per annum of butyl rubber, and is more preferably substantially free of butyl rubber. In addition, the elastomeric composition of each first and second outer layer 33A, 33B comprises at least 50 parts per annum of a diene elastomer, for example, natural rubber. Those skilled in the art will readily formulate and manufacture such compositions, which are identical herein.

[0214] An internal surface 34, intended to be in contact with the tire inflation gas, delimits a toroidal cavity 36 for inflating the tire 10.

[0215] The tire 10 comprises first and second inner layers 37A, 37B forming in part each first and second sidewall 30A, 30B, each first and second bead 32A, 32B and the crown 12. Each first and second outer layer 33A, 33B is arranged radially and axially outside each first and second inner layer 37A, 37B respectively, being in contact with each first and second inner layer 37A, 37B. Each first and second inner layer 37A, 37B forms at least part of the inner surface 34 and here the entirety of each first and second inner layer 37A, 37B forms at least part of the inner surface 34.

[0216] The tire 10 includes first and second radially internal reinforcement structures 3 8A, 38B respectively arranged in each first and second bead 32A, 32B.

[0217] Each first and second radially internal reinforcing structure 38A, 38B respectively comprises first and second circumferential radially internal reinforcing elements 40A, 40B, respectively arranged in each first and second bead 32A, 32B, here comprising first and second elements of wire reinforcements as described in WO2022 / 200717. More specifically, the first and second radially inner circumferential reinforcement elements 40A, 40B are arranged in each first and second outer layer 33A, 33B.

[0218] Each first and second bead 32A, 32B respectively comprises a first and second circumferential radially internal reinforcement element 42A, 42B, here a rod, intended to allow the tire 10 to be attached to a tire mounting support 10, for example a rim.

[0219] Each first and second internal radially reinforcing circumferential element 40A, 40B is respectively arranged radially outside each first and second internal radially reinforcing circumferential element 42A, 42B intended to allow the tire 10 to be attached to a tire mounting support 10.

[0220] The tire 10 further comprises first and second radially external reinforcement structures 44A, 44B arranged in the apex 12 and each provided respectively with a first and second circumferential radially external reinforcement element 46A, 46B arranged axially on either side of the median plane M of the tire 10 and here substantially symmetrically with respect to the median plane M of the tire 10. Each first and second circumferential radially external reinforcement element 46A, 46B is as described in WO2022 / 200717. More specifically, the first and second circumferential radially external reinforcement elements 46A, 46B are arranged respectively in each first and second inner layer 37A, 37B.

[0221] The tire 10 includes a carcass reinforcement 48 anchored in each first and second bead 32A, 32B, in this case wrapped around each first and second radially internal circumferential reinforcement element 42A, 42B intended to allow the tire 10 to be attached to a tire mounting support 10. The carcass reinforcement 48 extends into each first and second bead 32A, 32B and into each first and second sidewall 30A, 30B such that each first and second radially internal circumferential reinforcement element 40A, 40B is arranged radially inside the carcass reinforcement 48. The carcass reinforcement 48 also extends radially inward into the crown 12 of the crown reinforcement 16. The crown reinforcement 16 is arranged radially between the band of bearing 14 and the carcass reinforcement 48. The carcass reinforcement 48 comprises at least one layer of carcass 50 and here comprises a single layer of carcass 50.

[0222] Each first and second inner layer 37A, 37B and each first and second outer layer 33A, 33B is arranged radially and / or axially inside the single carcass layer 50.

[0223] The different top layers 24, 26, 28 and carcass 50 are identical to those described in WO2022 / 200717.

[0224] The tire 10 includes a stiffening structure 52 extending in the toroidal cavity 36 from the first bead 32A to the apex 12 and which is anchored in the first bead 32A by extending into the first bead 32A and here by being anchored around the first radially internal reinforcing structure 38A. The stiffening structure 52 extends in the toroidal cavity 36 from the second bead 32B to the apex 12 and is anchored in the second bead 32B by extending into the second bead 32B and here by being anchored around the second radially internal reinforcing structure 38B. The stiffening structure 52 extends in the toric cavity 36 from the first bead 32A and from the second bead 32B to the apex 12 and is anchored in the apex 12 by extending into the apex 12 and here by being anchored around the radially external reinforcing structures 44A, 44B.

[0225] The stiffening structure 52 comprises a plurality of stiffening elements 54 comprising a plurality of first stiffening elements 54A extending continuously in the toric cavity 36 and a plurality of second stiffening elements 54B extending continuously in the toric cavity 36. The first and second stiffening elements 54A, 54B are distributed circumferentially in the toric cavity 36.

[0226] Each stiffening element 54 is a textile yarn stiffening element comprising an assembly of three multifilament strands of aliphatic polyamide, for example nylon, these three multifilament strands being individually helicalized at 190 turns per meter in one direction and then helicalized together at 190 turns per meter in the opposite direction. Each of these multifilament strands has a count of 188 tex.

[0227] Each first stiffening element 54A extends continuously from the first side 30A and / or the first bead 32A to the top 12 and here from the first bead 32A to the top 12. Each second stiffening element 54B extends continuously from the second side 30A and / or the second bead 32A to the top 12 and here from the second bead 32A to the top 12.

[0228] In order to ensure optimal anchoring of the first and second stiffening elements 54A, 54B, each first and second radially internal reinforcing structure 38A, 38B, in particular each first and second circumferential radially internal reinforcing element 40A, 40B, has relatively high tensile and flexural stiffnesses. Furthermore, also with the aim of optimizing the anchoring of each stiffening element 54, the nominal secant modulus at 10% elongation of each first and second outer layer 33A, 33B is greater than or equal to 5 MPa and less than or equal to 60 MPa, preferably less than or equal to 20 MPa and here equal to 12 MPa.

[0229] In order to ensure optimal anchoring of the first and second stiffening elements 54A, 54B, each first and second radially external reinforcement structure 44A, 44B, in particular each first and second circumferential radially external reinforcement element 46A, 46B, has a relatively high tensile stiffness and a relatively low flexural stiffness in order to limit over-fretching of the top 12 and not risk damaging the flatness of the tread 14. In addition, still with the aim of optimizing the anchoring of each stiffening element 54, the nominal secant modulus at 10% elongation of each first and second inner layer 37A, 37B is greater than or equal to 1 MPa and less than or equal to 8 MPa, preferably less than or equal to 5 MPa, and here equal to 3 MPa.

[0230] Thus, first and second modulus ratios can be defined as the ratio between the nominal secant modulus at 10% elongation of each first and second outer layer 33A, 33B and the nominal secant modulus at 10% elongation of each first and second inner layer 37A, 37B, respectively. Each first and second modulus ratio is strictly greater than 1.0, preferably greater than or equal to 2.0, and more preferably greater than or equal to 3.0. Furthermore, each first and second modulus ratio is less than or equal to 20.0, preferably less than or equal to 15.0, more preferably less than or equal to 10.0, and even more preferably less than or equal to 7.0, and here equal to 4.0. Such first and second modulus ratios make it possible to improve the endurance of the stiffening structure 52.

[0231] Each first stiffening element 54A is anchored, in the first bead 32A, around the first radially internal reinforcing structure 38A, in particular around the first circumferential radially internal reinforcing element 40A. Each second stiffening element 54B is anchored in the second bead 32B, around the second radially internal reinforcing structure 38B, in particular around the second circumferential radially internal reinforcing element 40B. Here, each first and second stiffening element 54A, 54B is wrapped at least partially respectively around each first and second circumferential radially internal reinforcing element 40A, 40B.

[0232] Each first and second stiffening element 54A, 54B is also anchored, at the apex 12, respectively around each first and second radially external reinforcing structure 44A, 44B, in particular around each first and second circumferential radially external reinforcing element 46A, 46B. Here, each first and second stiffening element 54A, 54B is wrapped at least partially respectively around each first and second circumferential element of radially external reinforcement 46A, 46B.

[0233] Each first stiffening element 54A passes through the internal surface 34 at a first radially internal anchor point 56A arranged in the first bead 32A to anchor around the first radially internal reinforcement structure 38A and at a first radially external anchor point 58A arranged in the apex 12 to anchor around the first radially external reinforcement structure 44A. Thus, each first stiffening element 54A is anchored in the first bead 32A by extending into the first bead 32A from the first radially internal anchor point 56A. Each first stiffening element 54A is anchored in the apex 12 by extending into the apex 12 from the first radially external anchor point 58A.

[0234] Each second stiffening element 54B passes through the internal surface 34 at a second radially internal anchor point 56B arranged in the second bead 32B to anchor around the second radially internal reinforcement structure 38B and at a second radially external anchor point 58B arranged in the apex 12 to anchor around the second radially external reinforcement structure 44B. Thus, each second stiffening element 54B is anchored in the second bead 32B by extending into the second bead 32B from the second radially internal anchor point 56B. Each second stiffening element 54B is anchored in the apex 12 by extending into the apex 12 from the second radially external anchor point 58B.Each first stiffening element 54A comprises a radially internal anchoring portion 541, a portion 543, and a radially external anchoring portion 545, the portion 543 being extended on one side by the radially internal anchoring portion 541 and on the other side by the radially external anchoring portion 545.

[0235] Each second stiffening element 54B comprises a radially internal anchoring portion 542, a portion 544, and a radially external anchoring portion 546, the portion 544 being extended on one side by the radially internal anchoring portion 542 and on the other side by the radially external anchoring portion 546.

[0236] The portion 543 of each first stiffening element 54A extends continuously in the toric cavity 36 from the first radially internal anchor point 56A to the first radially external anchor point 58A.

[0237] The portion 544 of each second stiffening element 54B extends in the toric cavity 36 from the second radially internal anchor point 56B to the second radially external anchor point 58B.

[0238] The radially inner anchoring portion 541 of each first stiffening element- fication 54A extends from the first radially internal anchorage point 56A in the first bead 32A to anchor around the first radially internal reinforcement structure 38A.

[0239] The radially external anchorage portion 545 of each first stiffening element 54A extends from the first radially external anchorage point 58A in the apex 12 to anchor around the first radially external reinforcement structure 44A.

[0240] The radially internal anchorage portion 542 of each second stiffening element 54B extends from the second radially internal anchorage point 56B in the second bead 32B to anchor around the second radially internal reinforcement structure 38B.

[0241] The radially external anchorage portion 546 of each second ri-gidification element 54B extends from the second radially external anchorage point 58B in the vertex 12 to anchor around the second radially external reinforcement structure 44B.

[0242] The stiffening structure 52, here each first stiffening element 54A, and more specifically, each radially inner anchorage portion 541 and outer anchorage portion 545, penetrates the first inner layer 37A respectively at the first radially inner anchorage point 56A arranged in the first bead 32A and at the first radially outer anchorage point 58A arranged in the apex 12. The stiffening structure 52, here each first stiffening element 54A, and more specifically, each radially inner anchorage portion 541, passes through the first inner layer 37A and partially penetrates the first outer layer 33A from the first radially inner anchorage point 56A. The first inner layer 37A is in contact at least locally with the stiffening structure 52, and here in contact with each first stiffening element 54A, at the first radially inner anchorage point 56A and outer anchorage point 58A.

[0243] The stiffening structure 52, here each second stiffening element 54B, and more specifically, the radially inner anchoring portion 542 and outer anchoring portion 546, penetrates the second inner layer 37B respectively at the second radially inner anchoring point 56B arranged in the second bead 32B and at the second radially outer point 58B arranged in the vertex 12. The stiffening structure 52, here each second stiffening element 54B, and more specifically, the radially inner anchoring portion 542, passes through the second inner layer 37B and partially penetrates the second outer layer 33B from the second radially inner anchoring point 56B. The second inner layer 37B is in contact at least locally with the stiffening structure 52, and here in contact with each second stiffening element 54B, at the second point radially anchored internal 56B and external 58B.

[0244] Each first stiffening element 54A forms a continuous first stiffening element which meanders from the first bead 32A through the apex 12 and each second stiffening element 54B forms a continuous second stiffening element which meanders at least from the second bead 32B through the apex 12. More precisely, the first and second stiffening elements 54A, 54B form a continuous stiffening element which extends continuously from the first bead 32A to the second bead 32B through the apex 12 so as to meander from the first bead 32A to the second bead 32B.

[0245] As illustrated in [Fig. 1], the first radially external anchor point 58A is arranged axially on the same side as the first radially internal anchor point 56A and the first radially internal reinforcing structure 38A with respect to the median plane M. The second radially external anchor point 58B is arranged axially on the opposite side of the second radially internal anchor point 56B and the second radially internal reinforcing structure 38B with respect to the median plane M. Each first and second radially internal anchor point 56A, 56B and external anchor point 58A, 56B is arranged so that the portions 543, 544 do not intersect in the toric cavity 36.

[0246] With reference to [Fig.1], the thickness of each first and second inner layer 37A, 37B is greater than or equal to 0.1 mm and less than or equal to 5 mm, preferably greater than or equal to 0.1 mm and less than or equal to 2 mm and here equal to 0.5 mm at each first and second radially inner anchorage point 56A, 56B.

[0247] The thickness of each first and second outer layer 33A, 33B is greater than or equal to 2 mm and less than or equal to 20 mm and here equal to 4 mm at each first and second radially internal anchor point 56A, 56B.

[0248] Each first and second outer layer 33A, 33B and inner layer 37A, 37B comprises an elastomeric composition not intended for sealing. The elastomeric composition of each first and second outer layer 33A, 33B and inner layer 37A, 37B comprises less than 50 parts per annum of butyl rubber, preferably less than 10 parts per annum of butyl rubber, and is more preferably substantially free of butyl rubber. Furthermore, the elastomeric composition of each first and second outer layer 33A, 33B and inner layer 37A, 37B comprises at least 50 parts per annum of a diene elastomer, for example, natural rubber. The compositions of each first and second outer layer 33A, 33B are identical. The compositions of each first and second inner layer 37A, 37B are identical. A person skilled in the art will readily formulate and manufacture such compositions.

[0249] Alternatively, each first and second inner layer 37A, 37B could comprise a sealing composition comprising one or more butyl rubbers, for example such as those described in WO2016 / 001226A1. Such a composition comprises at least 50 parts per cent of the butyl rubber(s).

[0250] Each first and second stiffening element 54A, 54B, in particular each portion 541, 543, 545, 542, 544, 546 is coated with an adhesive composition, here an adhesive composition comprising an aldehyde / phenol resin based on resorcinol, formaldehyde and an elastomer latex as described in WO2013017422. Alternatively, any other adhesive composition described in WO2013017422 may be used.

[0251] The second embodiment illustrated in Figures 2 and 3, in which the elements identical to those in the preceding figures bear the same reference numerals, differs from the first embodiment illustrated in [Fig. 1] in that the pneumatic 10 also includes first radially internal anchoring members 60A arranged in the toroidal cavity 36 and projecting from the first bead 32A into the interior of the toroidal cavity 12, being in contact at least locally with the stiffening structure 52, here with each first stiffening element 54A. The pneumatic 10 also includes first radially external anchoring members 62A arranged in the toroidal cavity 36 and projecting from the apex 12 into the interior of the toroidal cavity 36, being in contact at least locally with the stiffening structure 52, here with each first stiffening element 54A.

[0252] The tire 10 also includes second radially internal anchoring members 60B arranged in the toroidal cavity 36 and projecting from the second bead 32B into the toroidal cavity 36, being in contact at least locally with the stiffening structure 52, here with each second stiffening element 54B. The tire 10 also includes second radially external anchoring members 62B arranged in the toroidal cavity 36 and projecting from the apex 12 into the toroidal cavity 36, being in contact at least locally with the stiffening structure 52, here with each second stiffening element 54B.

[0253] Each first and second radially internal anchoring member 60A, 60B is formed from material with each first and second bead 32A, 32B respectively. Each first and second radially external anchoring member 62A, 62B is formed from material with the apex 12. Furthermore, each first and second internal layer 37A, 37B forms at least partially each first and second radially internal anchoring member 60A, 60B and external anchoring member 62A, 62B. In this case, each first and second radially internal anchoring member 60A, 60B comprises a skin formed respectively by each first and second inner layer 37A, 37B and a core formed respectively by each first and second outer layer 33A, 33B, this core-skin structure being due to the fineness of the composition of each first and second outer layer 33A, 33B during the molding and vulcanization of the tire 10. Each first and second inner layer 37A, 37B forms the entirety respectively of each first and second radially outer anchoring element 62A, 62B.

[0254] Alternatively, it may be imagined that each first and second inner layer 37A, 37B forms the entirety of each first and second radially inner anchoring member 60A, 60B.

[0255] Each first and second radially internal anchoring element 60A, 60B and external 62A, 62B has a stud shape, in particular a stud whose height is greater than 1 mm, in particular greater than 2 mm, more particularly greater than 3 mm.

[0256] The tire 10 further comprises first and second inner complementary layers 18A, 18B forming in part each first and second sidewall 30A, 30B, each first and second bead 32A, 32B and the crown 12. Each first and second inner complementary layer 18A, 18B is arranged radially and / or axially within each first and second inner layer 37A, 37B respectively and in contact with each first and second inner layer 37A, 37B respectively. The first inner complementary layer 18A is arranged radially inward and outward from the first anchor points 56A, 58A and the second inner complementary layer 18B is arranged radially inward and outward from the second anchor points 56B, 58B. Each first and second inner complementary layer 18A, 18B forms in part the inner surface 34.Each first and second complementary inner layer 18A, 18B is a sealing layer for at least one blowing gas and comprises a sealing composition including one or more butyl rubbers, for example as described in WO2016 / 001226A1. Such a composition comprises at least 50 parts per liter of the butyl rubber(s).

[0257] The third embodiment illustrated in [Fig. 4], in which the elements identical to those in the preceding figures bear the same reference numerals, differs from the first embodiment illustrated in [Fig. 1] in that the tire 10 comprises first and second complementary inner layers 18A, 18B forming the inner surface 34, and in that the stiffening structure 52, here each first and second stiffening element 54A, 54B and more precisely each radially inner portion 541, 542 and outer portion 545, 546 respectively passes through each first and second complementary inner layer 18A, 18B from the first and second radially internal anchor points 56A, 58A and external 58A, 58B of each first and second complementary internal layer 18A, 18B.

[0258] Thus, each first and second complementary inner layer 18A, 18B is here in contact at least locally with the stiffening structure 52, here respectively with each first and second stiffening element 54A, 54B at the first and second radially inner anchorage point 56A, 56B and outer 58A, 58B.

[0259] Each first and second complementary inner layer 18A, 18B is such that the first and second ratios of complementary moduli between a nominal secant modulus at 10% elongation of each first and second inner layer 37A, 37B, here equal to 3 MPa, and a nominal secant modulus at 10% elongation respectively of each first and second complementary inner layer 18A, 18B, here equal for example to 1.5 MPa, is strictly greater than 1.0 and here equal to 2.0.

[0260] Alternatively, first and second complementary modulus ratios could be imagined to be less than or equal to 1.0. Comparative tests

[0261] A control tire having first and second modulus ratios equal to 1.0, i.e., comprising the same elastomeric composition for both the outer and inner layers, was digitally tested. A tire according to the invention, identical to the tire according to the first embodiment, was also digitally tested.

[0262] The addition of a stiffness gradient between the outer and inner layers, defining first and second modulus ratios strictly greater than 1.0, has significantly improved the endurance of the stiffening structure. For example, for first and second modulus ratios of 4.0, numerical tests showed a reduction of more than 40% in the displacement of the stiffening elements in the structure of the tire according to the invention compared to the control tire, as well as a reduction of nearly 50% in the stresses exerted by the stiffening elements on the layer first penetrated by the stiffening elements, namely each first and second inner layer of the tire according to the invention, compared to the layer first penetrated by the stiffening elements of the control tire.

Claims

Demands

1. A tire (10) comprising a crown (12), first and second sidewalls (30A, 30B) each extending radially inward from the crown (12), and first and second beadings (32A, 32B) extending radially inward from the first and second sidewalls (30A, 30B), the tire (10) having an internal surface (34) defining a toroidal cavity (36) for inflating the tire (10), the tire (10) comprising: - a first inner layer (37) forming at least part of the first sidewall (30A) and / or bead (32A) and / or the crown (12), - a first outer layer (33A) forming at least part of the first sidewall (30A) and / or bead (32A) and / or the crown (12), and arranged radially and / or axially outside the first inner layer (37A) while in contact with the first inner layer (37A),- a stiffening structure (52) extending continuously in the toroidal cavity (36) from at least the first flank (30A) and / or bead (32A) to at least the apex (12) and being anchored in the first flank (30A) and / or bead (32A) and / or in the apex (12) by extending into the first flank (30A) and / or bead (32A) and / or the apex (12), said stiffening structure (52) traversing the first inner layer (37A) and penetrating at least partially the first outer layer (33A) in the first flank (30A) and / or bead (32A) and / or the apex (12), characterized in that a first ratio of moduli between a nominal secant modulus at 10% elongation of the first outer layer (33A) and a nominal secant modulus at 10% elongation of the first inner layer (37A) is strictly greater than 1.

0.

2. Pneumatic (10) according to the preceding claim, comprising: - a second inner layer (37B) forming at least part of the second flank (30B) and / or bead (32B) and / or the apex (12), - a second outer layer (33B) further forming at least part of the second flank (30B) and / or bead (32B) and / or the apex (12), and arranged radially and / or axially outside the second inner layer (37B) while being in contact with the second inner layer (37B), - the stiffening structure (52) extending continuously into the cavity toroid (36) from at least the second flank (30B) and / or bead (32B) to at least the apex (12) and being anchored in the second flank (30B) and / or bead (32B) and / or in the apex (12) extending into the second flank (30B) and / or bead (32B) and / or into the apex (12), said stiffening structure (52) passing through the second inner layer (37B) and penetrating at least in part the second outer layer (33A) into the second flank (30A) and / or bead (32A) and / or the apex (12), a second ratio of moduli between a nominal secant modulus at 10% elongation of the second outer layer (33B) and a nominal secant modulus at 10% elongation of the second inner layer (37B) is strictly greater than 1.

0.

3. Pneumatic (10) according to any one of the preceding claims, wherein the first and / or second modulus ratio is greater than or equal to 2.0, preferably greater than or equal to 3.

0.

4. Pneumatic (10) according to any one of the preceding claims, wherein the first modulus ratio is less than 20.0, preferably less than or equal to 15.0, more preferably less than or equal to 10.0 and even more preferably less than or equal to 7.

0.

5. Pneumatic (10) according to any one of the preceding claims, wherein the nominal secant modulus at 10% elongation of the first outer layer (33A, 33B) is greater than or equal to 5 MPa.

6. Pneumatically (10) according to any one of the preceding claims, wherein the nominal secant modulus at 10% elongation of the first outer layer (33A, 33B) is less than or equal to 60 MPa, preferably less than or equal to 20 MPa.

7. Pneumatic (10) according to any one of the preceding claims, wherein the nominal secant modulus at 10% elongation of the first inner layer (37A, 37B) is less than or equal to 8 MPa, preferably less than or equal to 5 MPa.

8. Pneumatic (10) according to any one of claims 1 to 7, wherein the first inner layer (37A) forms at least in part the inner surface (34), said stiffening structure (52) penetrating the first inner layer at a first anchorage point (56A, 58A) radially inside and / or outside the first inner layer (37A) arranged in the first sidewall (30A) and / or bead (32A) and / or top (12).

9. Pneumatic (10) according to claim 8, wherein the entirety of the first inner layer (37A) forms at least part of the inner surface.

10. Pneumatic (10) according to claim 8, comprising a first complementary inner layer (18A) forming in part at least the first sidewall (30A) and / or bead (32A) and / or the top (12) and arranged radially and / or axially inside the first inner layer (37A), the first complementary inner layer (18A) forming at least in part the inner surface (34), the first complementary inner layer (18A) is arranged at a distance from said first anchor point (56A, 58A) radially inside and / or outside the stiffening structure (52).

11. Pneumatic (10) according to the preceding claim, wherein the first inner complementary layer (18A) is a sealing layer for at least one inflation gas.

12. Pneumatic (10) according to any one of claims 1 to 7, comprising a first inner complementary layer (39) forming at least part of the first sidewall (30A) and / or bead (32A) and / or the top (12) and arranged radially and / or axially inside the first inner layer (37A), the first inner complementary layer (39) forming at least part of the inner surface (34), said stiffening structure (52) passing through the first inner complementary layer and penetrating the first inner complementary layer at a first anchoring point (56A, 58A) radially inside and / or outside the first inner complementary layer arranged in the first sidewall (30A) and / or bead (32A) and / or the top (12).

13. Pneumatic (10) according to any one of the preceding claims, comprising a first anchoring member (60A, 62A) arranged in the toroidal cavity (36) and extending in projection from the first flank (30A) and / or bead (32A) into the interior of the toroidal cavity (36) and / or from the apex into the interior of the toroidal cavity (36) being in contact at least locally with said stiffening structure (52), the first inner layer forming at least a part of said first anchoring member.

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