Method for manufacturing a tyre comprising a layer of a crosslinked polymer composition interposed between a stiffening structure and a reinforcing structure

Abstract

This method for manufacturing a tyre comprising a crown, sidewalls, beads, and a stiffening structure anchored around a radially inner reinforcing structure comprises: - laying (S1A) a radially inner layer of a crosslinkable polymer composition so as to at least partially cover the radially inner reinforcing structure; - at least partially crosslinking (S3A) the radially inner layer of the crosslinkable polymer composition; - placing (S9) the stiffening structure in the sidewall and / or bead such that the radially inner layer of the at least partially crosslinked polymer composition is interposed between the stiffening structure and the radially inner reinforcing structure, and - a step (S11) of curing the tyre.

Description

[0001] A method for manufacturing a tire comprising a layer of cross-linked polymer composition interposed between a stiffening structure and a reinforcing structure.

[0002] technical field

[0003] The present invention relates to a method for manufacturing a tire as well as the tire obtained by this method, in particular a tire for passenger vehicles.

[0004] A tire is defined as a band 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 tire according to the invention has a substantially toroidal structure of revolution around a principal axis of the tire, this principal axis coinciding with the axis of rotation of the tire.

[0005] Previous techniques

[0006] 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 ribs designed to contact a mounting support, such as a rim. Each first and second bead includes a circumferential reinforcing element to secure the tire to the mounting support.

[0007] The tire includes an internal surface defining a toroidal cavity for inflating the tire once it is mounted on the mounting support.

[0008] The tire described in WO2020 / 128225 comprises a stiffening structure including first stiffening elements extending continuously within the toroidal cavity from the first bead to the apex and second stiffening elements extending continuously within the toroidal cavity from the second bead to the apex. Each first and second stiffening element is fixed to each bead from which it extends by 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 fixed to the apex of the tire by an apex interface between the stiffening element and a portion of the inner surface of the apex. Each bead-apex interface includes an elastomeric compound cushion positioned between the stiffening element and the corresponding portion of the inner surface.

[0009] It was observed 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 of the apex, and therefore to premature failure of the stiffening structure.

[0010] The durability of the tire described in WO2020 / 128225 was improved in W02022 / 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 W02022 / 200717, particularly the durability of the anchoring of the first and second stiffening elements in each first and / or bead, while significantly improved compared to that of the tire described in WO2020 / 128225, proved imperfect due to failures of some of the first and second stiffening elements in certain use cases.

[0011] The invention aims to improve the endurance of the stiffening structure described in WO2020 / 128225 and W02022 / 200717.

[0012] Description of the invention

[0013] The invention relates to a method for manufacturing 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;

[0014] - an internal surface delimiting a toroidal inflation cavity for the tire, the tire having a substantially toroidal shape around an axis of revolution;

[0015] - a stiffening structure extending continuously within the toroidal cavity from at least the first sidewall and / or bead to at least the apex, said stiffening structure being anchored at least in the first sidewall and / or bead and / or in the apex, said stiffening structure being anchored in or around a first radially internal reinforcement structure of the tire arranged in the first sidewall and / or bead and / or in or around one or more radially external reinforcement structure(s) arranged in the apex, the tire comprising:

[0016] - a first layer of a first radially cross-linked internal polymer composition interposed between said stiffening structure and said first radially internal reinforcement structure and / or a layer of a radially cross-linked external polymer composition interposed between said stiffening structure and said or one of said radially external reinforcement structure(s), the process comprising the following steps:

[0017] - a step of applying a first layer of a first radially crosslinkable polymer composition so as to cover at least part of said first radially inner reinforcing structure and / or a step of applying a layer of a radially crosslinkable polymer composition so as to cover at least part of said or one of said radially outer reinforcing structure(s); - a step of at least partial crosslinking of said first layer of the first radially crosslinkable polymer composition and / or a step of at least partial crosslinking of said layer of said radially outer crosslinkable polymer composition;

[0018] - a step of placing said stiffening structure in the first flank and / or bead and the top such that said first layer of the first at least partially radially cross-linked inner polymer composition is interposed between said stiffening structure and said first radially inner reinforcement structure, and / or such that said layer of said at least partially radially cross-linked outer polymer composition is interposed between said stiffening structure and said or one of said radially outer reinforcement structure(s), and

[0019] - subsequent to the at least partial crosslinking step of said first layer of the first radially crosslinkable inner polymer composition and / or the at least partial crosslinking step of said layer of said radially crosslinkable outer composition and subsequent to the step of setting up said stiffening structure, a tire curing step.

[0020] As explained below, the invention functions as soon as it is applied to one side of the tire, here at least to the side comprising the first sidewall and / or bead, and / or as soon as it is applied to the crown. Advantageous embodiments allow the invention to be applied to both sides of the tire, although this is not necessary to achieve the invention. Thus, in the present application, the use of the qualifier "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 qualifier "second" is intended, unless otherwise obviously interpreted, to associate the element designated as "second" with the second sidewall and / or bead.

[0021] Advantageously, the first sidewall and / or bead is positioned on the same side of the tire's median plane as the outer sidewall. Thus, the stiffening structure acts on the side of the tire most stressed during high-velocity drifts. By inner and outer sides, we mean that the tire is designed so that one side is positioned on the inside and the other on the outside. This orientation, imposed by the tire manufacturer, ensures that the tire performs as intended. Indeed, mounting a tire with an orientation different from that specified by the manufacturer can lead to suboptimal vehicle handling. The outer sidewall refers to the side of the tire that is fully visible from outside the vehicle when the tire is mounted.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.

[0022] In this application, the reference to a radially internal composition during the process steps is made because of its final positioning within the tire obtained by the process, thus distinguishing it from a potentially radially external composition during the process steps. Similarly, the reference to a radially external composition during the process steps is made because of its final positioning within the tire obtained by the process, thus distinguishing it from a potentially radially internal composition during the process steps.

[0023] 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 stiffening structure extends continuously within the toroidal cavity from at least the second sidewall and / or bead to at least the apex, said stiffening structure being anchored at least in the second sidewall and / or bead, said stiffening structure being anchored in or around a second radially internal reinforcement structure of the tire arranged in the second sidewall and / or bead, the tire comprising a second layer of a second radially internal cross-linked polymer composition interposed between said second stiffening structure and said second radially internal reinforcement structure; the method comprising the following steps:

[0024] - a step of applying a second layer of a second radially crosslinkable polymer composition inward so as to cover at least part of said second radially internal reinforcing structure;

[0025] - a crosslinking step, at least partial, of said second layer of the second radially inner crosslinkable polymer composition;

[0026] - a step of placing said stiffening structure in the second flank and / or bead and the top such that said second layer of the second polymer composition, at least partially radially crosslinked internally, is interposed between said stiffening structure and said second radially internal reinforcing structure, and

[0027] - subsequent to the at least partial crosslinking step of said second layer of the second radially crosslinkable inner polymer composition and subsequent to the setting-up step of said stiffening structure, a curing step of the tire.

[0028] It was observed that the stiffening structure degraded, sometimes to the point of failure, due to friction and contact between the stiffening structure and the relevant reinforcement structure. This failure occurred particularly at the point where the stiffening structure was anchored.

[0029] In particular, in cases where the stiffening structure has a relatively high thermosensitivity, the contraction of the stiffening structure can lead to a closer proximity of the stiffening structure and the reinforcement structure concerned, and therefore to relatively significant friction and contact during the use of the tire.

[0030] Each layer of cross-linked polymer composition limits friction and contact between the stiffening structure and the relevant reinforcement structure, preventing degradation that could lead to at least partial failure of the stiffening structure in certain usage scenarios. The protective function is achieved, firstly, by the mechanical decoupling of the cross-linked polymer composition layer between the stiffening and reinforcement structures. Secondly, the protective function is achieved by creating a separation between the stiffening and reinforcement structures. This separation means that the stiffening structure is not in direct contact with the reinforcement structure. This separation is ensured by the size of the cross-linked polymer composition layer, which creates the necessary space to protect the stiffening structure.

[0031] Furthermore, the layer of cross-linked polymer composition considered makes it possible to increase the surface area over which the forces transmitted from said stiffening structure to said corresponding radially internal and / or external reinforcing structure are distributed, and therefore to reduce these forces.

[0032] By implementing at least a partial crosslinking of the crosslinkable polymer layer before applying the stiffening structure to the corresponding sidewall and / or bead and / or crown, creep susceptibility is reduced by stiffening the at least partially crosslinked polymer layer, particularly within the temperature range typically used during the curing process. The crosslinking step stiffens the crosslinkable polymer layer so that the stiffening structure does not penetrate it during the tire curing process.Indeed, when the crosslinking step of the crosslinkable polymer composition layer in question is not carried out at least partially, the tire curing step, particularly when the stiffening structure has a relatively high thermosensitivity, can generate stresses which cause the stiffening structure to come into contact with the corresponding reinforcement structure.

[0033] Partial crosslinking is defined as the crosslinkable polymer composition exhibiting, after the crosslinking step, partial crosslinking in some embodiments and complete crosslinking in others. Partial crosslinking is such that, when the partially crosslinked polymer composition is introduced into an oscillating chamber rheometer at 150°C according to DIN 53529 - Part 3 of June 1983, the rheometric torque of the partially crosslinked composition continues to increase over time. Complete crosslinking is such that, when the fully crosslinked polymer composition is introduced into an oscillating chamber rheometer at 150°C according to DIN 53529 - Part 3 of June 1983, the rheometric torque of the fully crosslinked composition has reached a plateau and is substantially constant.

[0034] Thus, an anchorage according to the invention is significantly more robust than the bead interfaces described in WO2020 / 128225 and the anchorage described in W02022 / 200717.

[0035] By interposed, we mean that the cross-linked polymer composition layer is positioned geometrically between the stiffening structure and the relevant reinforcing structure.

[0036] A polymeric composition comprises one or more polymers. A crosslinkable composition hardens under the effect of a crosslinking agent. An example of a crosslinkable composition is a composition based on an elastomer and a crosslinking system that hardens under the effect of relative heating. An example of an elastomer and a crosslinking system is a diene elastomer and a vulcanizing system, for example, containing sulfur. Other crosslinking systems can also be considered, for example, peroxide crosslinking or molecular crosslinking. Naturally, there can be one or more radially crosslinked inner layers of polymeric composition(s) and / or one or more radially crosslinked outer layers of polymeric composition(s).

[0037] In addition, in addition to the layer(s) of crosslinked polymer composition(s), a layer of a composition other than a crosslinked polymer composition may be interposed between the stiffening structure and the radially internal and / or external reinforcing structure concerned, for example a layer of a thermoplastic polymer composition.

[0038] In embodiments: said first layer of radially crosslinked inner polymer composition is in contact with said stiffening structure and / or said first radially inner reinforcement structure, and / or said layer of radially crosslinked outer polymer composition is in contact with said stiffening structure and / or said or one of said radially outer reinforcement structure(s).

[0039] Optionally, said second layer of radially crosslinked inner polymer composition is in contact with said stiffening structure and / or said second radially inner reinforcing structure.

[0040] Alternatively, the relevant crosslinked polymer composition layer is not in contact with said stiffening structure, for example because a composition layer other than a crosslinked polymer composition layer is interposed between the stiffening structure and the relevant radially internal and / or external reinforcing structure.

[0041] 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.

[0042] Among other advantages, the stiffening structure allows for the simultaneous increase of 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.

[0043] By increasing radial stiffness, the stiffening structure limits radial deformation of the tread 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 especially 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 remains unchanged, which allows the tire to maintain the same grip performance as the tire described in WO2017 / 005713.

[0044] By increasing axial and drift stiffness, the stiffening structure will contribute to improved behavior under lateral stress, for example during a drift roll. Furthermore, under lateral stress, the contact area with the ground ensures a more homogeneous distribution of contact pressures, thus increasing lateral grip.

[0045] Furthermore, the stiffening structure contributes at least partially to supporting 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 located opposite the contact area is placed in tension. Conversely, in some embodiments, a portion of the stiffening structure located at the contact area is subjected to buckling in compression.

[0046] The presence of the stiffening structure thus reduces the tire's contribution to load-bearing capacity, thereby allowing for a reduction in its structural rigidity, for example, by reducing the volume of the beading. Indeed, the beading of a conventional tire dissipates a significant amount of energy due to its volume and the hysteresis of its constituent elastomeric compound. Reducing its volume therefore significantly reduces rolling resistance.

[0047] 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 classically used by those skilled in the art: an axial direction, a circumferential direction, and a radial direction.

[0048] Axial direction means the direction substantially parallel to the axis of revolution of the tire, that is to say the axis of rotation of the tire.

[0049] 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).

[0050] 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.

[0051] By median plane of the tire, denoted M, we mean the plane perpendicular to the axis of rotation of the tire which is located at mid-axial distance of the two ridges and passes through the axial midpoint of the apex reinforcement.

[0052] The circumferential equatorial plane of the tire, denoted E, is defined, in a meridional cross-sectional plane, as 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 cross-sectional plane (a 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.

[0053] By meridian plane, we mean a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0054] Radially inside and radially outside refer to the area closest to and furthest from the tire's axis of rotation, respectively. Axially inside and axially outside refer to the area closer to and furthest from the tire's median plane, respectively.

[0055] The bead is the radial portion of the tire designed to allow the tire to be attached to a mounting surface, such as a wheel with a rim. Each bead is specifically designed to make contact with a hook on the rim, enabling it to be attached. The bead is thus delimited radially on the inside by the innermost radial end of the tire and radially on the outside 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 (ETRTO) standard, 2024.

[0056] The sidewall is defined as 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 2024 standard manual. The edges are arranged on either side of the tire's median plane and are formed by lines substantially parallel to the tire's circumferential direction. In the case of a clear boundary between the tread and the sidewall, 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 2024 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, 2024.

[0057] Any range of values ​​designated by the expression "between a and b" represents the range of values ​​from more than a to less than b (i.e., bounds a and b excluded) while any range of values ​​designated by the expression "from a to b" means the range of values ​​from a to b (i.e., including the strict bounds a and b).

[0058] The tires of the invention are preferably intended for passenger vehicles as defined in the European Tyre and Rim Technical Organisation or "ETRTO" standard, 2024. Such a tire has a cross-section in a meridian plane characterized by a section height H and a nominal section width SW as defined in the European Tyre and Rim Technical Organisation or "ETRTO" standard, 2024. The values ​​of SW and H are indicated on the tire sidewall marking, for example as defined according to the ETRTO manual, 2024.

[0059] Preferably, the passenger vehicle tires to which the invention will be advantageously 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.

[0060] In embodiments, the stiffening structure extending into the toroidal cavity from at least the first flank and / or bead to at least the apex, being anchored in the apex, and extending into the toroidal cavity from at least the second flank and / or bead to at least the apex, being anchored in the apex, said stiffening structure being anchored in or around one or more radially external reinforcing structure(s) arranged in the apex, the tire comprises a radially external cross-linked polymer composition layer interposed between said stiffening structure and said or one of said radially external reinforcing structure(s), the method comprising the following steps:

[0061] - a step of applying a layer of a radially externally crosslinkable polymeric composition so as to cover at least part of said or one of said radially external reinforcing structure(s);

[0062] - a crosslinking step, at least partial, of said outer radially crosslinkable polymeric composition layer;

[0063] - a step of placing said stiffening structure in the first flank and / or bead and the top such that said layer of said at least partially radially cross-linked external polymer composition is interposed between said stiffening structure and said or one of said radially external reinforcing structure(s), and

[0064] - subsequent to the at least partial crosslinking step of said layer of said radially crosslinkable outer polymer composition and subsequent to the step of setting up said stiffening structure, a tire curing step.

[0065] According to a first design, said first radially internal reinforcing structure comprising a first circumferential radially internal reinforcing element, the step of laying said first layer of the first radially internal crosslinkable polymer composition includes the formation of a first sheath of the first radially internal crosslinkable polymer composition around said first circumferential radially internal reinforcing element, and / or said or one of said radially external reinforcing structure(s) comprising a circumferential radially external reinforcing element, the step of laying said layer of said radially external crosslinkable polymer composition includes the formation of a sheath of the radially external crosslinkable polymer composition around said or one of said circumferential radially external reinforcing element(s).

[0066] Optionally, according to the first design, said second radially internal reinforcing structure comprising a second circumferential radially internal reinforcing element, the step of laying said second layer of the second radially internal crosslinkable polymer composition includes the formation of a second sheath of the second radially internal crosslinkable polymer composition around said second circumferential radially internal reinforcing element.

[0067] The term "sheath formation" of the circumferential element in question means that the layer of the relevant crosslinkable polymer composition covers and surrounds said circumferential element. In other words, the layer of the relevant crosslinkable polymer composition encases said circumferential element.

[0068] Advantageously, according to the first design, the at least partial crosslinking step of said first layer of the first radially crosslinkable inner polymer composition and / or the at least partial crosslinking step of said layer of the radially crosslinkable outer polymer composition is carried out after the laying step of said first layer of the first radially crosslinkable inner polymer composition and / or the laying step of said layer of said radially crosslinkable outer polymer composition.

[0069] Optionally, according to the first design, the step of at least partial crosslinking of said second layer of the second radially crosslinkable inner polymer composition is carried out after the step of laying said second layer of the second radially crosslinkable inner polymer composition.

[0070] Thus, at least partial crosslinking of the layer concerned is carried out on the corresponding circumferential reinforcing element.

[0071] Advantageously, according to the first design, the process comprises, after the at least partial crosslinking step of said first layer of the first radially crosslinkable inner polymer composition and / or after the at least partial crosslinking step of said layer of said radially crosslinkable outer polymer composition, a step of placing said first radially inner sheathed circumferential reinforcing element in the first flank and / or bead and / or a step of placing said radially outer sheathed circumferential reinforcing element in the top.

[0072] Optionally, according to the first design, the process includes, after the step of at least partial crosslinking of said second layer of the second radially crosslinkable inner polymer composition, a step of placing said second circumferential radially inner reinforcing element sheathed in the second flank and / or bead.

[0073] This reduces the cycle time of the process by conducting, independently of the other process steps, at least partial crosslinking of the relevant polymer composition layer sheathing the corresponding circumferential reinforcement element.

[0074] According to a second alternative design, the step of laying said first layer of the first radially crosslinkable inner polymer composition includes laying a first strip of the first radially crosslinkable inner polymer composition, and / or the step of laying said layer of said radially crosslinkable outer polymer composition includes laying a strip of the radially crosslinkable outer polymer composition.

[0075] Optionally, according to the second design, the step of laying said second layer of the second inner radially crosslinkable polymer composition includes laying a second strip of the second inner radially crosslinkable polymer composition.

[0076] Advantageously, according to the second design, the process includes, before the step of laying said first layer of the first radially crosslinkable polymer composition inside and / or before the step of laying said layer of said radially crosslinkable polymer composition outside, a step of placing said first radially inner reinforcing structure in the first flank and / or bead and / or a step of placing said or one of said radially outer reinforcing structure(s) in the top.

[0077] Optionally, according to the second design, the process includes, before the step of laying said second layer of the second radially crosslinkable polymer composition inside, a step of placing said second radially internal reinforcing structure in the second flank and / or bead.

[0078] Advantageously, according to the second design, the at least partial crosslinking step of said first layer of the first radially crosslinkable inner polymer composition and / or the at least partial crosslinking step of said layer of said radially crosslinkable outer polymer composition is carried out after the laying step of said first layer of the first radially crosslinkable inner polymer composition and / or the laying step of said layer of said radially crosslinkable outer polymer composition.

[0079] Optionally, according to the second design, the step of at least partial crosslinking of said second layer of the second radially crosslinkable inner polymer composition is carried out after the step of laying said second layer of the second radially crosslinkable inner polymer composition.

[0080] Conducting the crosslinking step after the application step allows the raw adhesion ("tack" in English) of the crosslinkable polymer composition concerned to be taken into account and ensures good adhesion of the crosslinkable polymer composition concerned during the tire manufacturing process.

[0081] Alternatively, still according to the second design, the at least partial crosslinking step of said first layer of the first radially crosslinkable inner polymer composition and / or the at least partial crosslinking step of said layer of said radially crosslinkable outer polymer composition is carried out prior to the laying step of said first layer of the first radially crosslinkable inner polymer composition and / or the laying step of said layer of said radially crosslinkable outer polymer composition.

[0082] Optionally, in this alternative, according to the second design, the at least partial crosslinking step of said second layer of the second radially crosslinkable inner polymer composition is carried out prior to the laying step of said second layer of the second radially crosslinkable inner polymer composition.

[0083] In this alternative, the cycle time is reduced by using the polymer composition already partially crosslinked, which will have advantageously undergone at least partial crosslinking in masked time.

[0084] According to a first variant, the at least partial crosslinking step of said first layer of the first radially crosslinkable inner polymer composition and / or the at least partial crosslinking step of said layer of said radially crosslinkable outer polymer composition includes the complete crosslinking of said first layer of the first radially crosslinkable inner polymer composition and / or of said layer of said radially crosslinkable outer polymer composition.

[0085] Optionally, according to the first variant, the at least partial crosslinking step of said second layer of the second inner radially crosslinkable polymer composition includes the complete crosslinking of said second layer of the second inner radially crosslinkable polymer composition.

[0086] This minimizes the risk of the stiffening structure penetrating the layer in question. Furthermore, complete cross-linking is easy to control industrially.

[0087] Complete crosslinking of the polymer composition in question does not preclude the possible co-crosslinking of the corresponding layer with the additional crosslinkable composition(s). Indeed, despite reaching a plateau of rigidity, the polymer composition still contains available crosslinking sites, for example unsaturations in the case of an unsaturated elastomer, with the crosslinking agent of the additional crosslinkable composition(s), for example sulfur in the case of vulcanization.

[0088] According to a second alternative variant, the at least partial crosslinking step of said first layer of the first radially crosslinkable inner polymer composition comprising the partial crosslinking of said first layer of the first radially crosslinkable inner polymer composition and / or the at least partial crosslinking step of said layer of said radially crosslinkable outer polymer composition comprising the partial crosslinking of said layer of the radially crosslinkable outer polymer composition, the tire curing step allows the complete crosslinking of said first layer of the first radially crosslinkable inner polymer composition and / or of said layer of said radially crosslinkable outer polymer composition.

[0089] Optionally, according to the second alternative variant, the at least partial crosslinking step of said second layer of the second radially crosslinkable inner polymer composition including the partial crosslinking of said second layer of the second radially crosslinkable inner polymer composition, the tire curing step allows the complete crosslinking of said second layer of the second radially crosslinkable inner polymer composition.

[0090] Thus, the curing stage of the tire helps to strengthen adhesion by co-crosslinking between the layer of partially crosslinked polymeric composition concerned and the adj acent composition(s).

[0091] In certain advantageous embodiments, the process includes, prior to the step of placing said stiffening structure in the first flank and / or bead and the top, a step of placing a first intermediate layer of a first radially internal raw polymer composition interposed between said stiffening structure and said first layer of first at least partially radially crosslinked polymer composition, and / or a step of placing an intermediate layer of a radially external raw polymer composition interposed between said stiffening structure and said layer of said at least partially radially crosslinked polymer composition.

[0092] Optionally, the process includes, prior to the step of placing said stiffening structure in the second flank and / or bead and the top, a step of placing a second intermediate layer of a second raw radially internal polymer composition interposed between said stiffening structure and said second layer of first at least partially radially internally crosslinked polymer composition.

[0093] Thus, the final adhesion between the stiffening structure and the at least partially crosslinked polymer composition layer considered is improved by means of the intermediate layer.

[0094] Raw means a polymeric composition that has not undergone a crosslinking step.

[0095] Advantageously, said stiffening structure comprises at least a first stiffening element comprising a radially internal anchoring portion extending into the first flank and / or bead and / or a radially external anchoring portion extending into the apex, said first layer of radially internal cross-linked polymer composition is interposed between, preferably in contact with, said first radially internal reinforcing structure and the radially internal anchoring portion of said first stiffening element, and / or said layer of radially external cross-linked polymer composition is interposed between, preferably in contact with, said or one of said radially external reinforcing structure(s) and the radially external anchoring portion of said first stiffening element,The step of placing said first stiffening structure in the first flank and / or bead and the top is carried out so that said first layer of the first at least partially radially cross-linked inner polymer composition is interposed between, preferably in contact with, said first radially inner reinforcing structure and the radially inner anchoring portion of said first stiffening element, and / or so that the layer of the at least partially radially cross-linked outer polymer composition is interposed between, preferably in contact with, said or one of said radially outer reinforcing structure(s) and the radially outer anchoring portion of said first stiffening element.

[0096] Optionally, said stiffening structure includes at least a second stiffening element comprising a radially internal anchoring portion extending into the second flank and / or bead, said second layer of radially internal crosslinked polymer composition is interposed between, preferably in contact with, said second radially internal reinforcing structure and the radially internal anchoring portion of said second stiffening element, the step of placing said stiffening structure in the second flank and / or bead and the top is conducted so that said second layer of the second at least partially radially internal crosslinked polymer composition is interposed between, preferably in contact with, said second radially internal reinforcing structure and the radially internal anchoring portion of said second stiffening element.

[0097] Advantageously, said first stiffening element penetrates the top at a first radially external anchor point of said first stiffening element.

[0098] Optionally, said second stiffening element penetrates the apex at a second radially external anchor point of said second stiffening element. Advantageously, said first stiffening element comprises a portion extending continuously within the toroidal cavity from the first radially internal anchor point to the first radially external anchor point.

[0099] Advantageously, the radially inner anchoring portion of said first stiffening element extends the portion extending continuously into the toroidal cavity.

[0100] Advantageously, said first stiffening element includes a radially external anchoring portion extending from the first radially external anchoring point in the apex and extending the portion extending continuously into the toric cavity.

[0101] Optionally, said second stiffening element includes a portion extending continuously in the toroidal cavity from the second radially inner anchor point to the second radially outer anchor point.

[0102] Optionally, the radially inner anchoring portion of said second stiffening element extends the portion extending continuously into the toroidal cavity.

[0103] Optionally, said second stiffening element includes a radially external anchoring portion extending from the second radially external anchoring point in the apex and extending the portion extending continuously into the toroidal cavity.

[0104] Advantageously, said radially external anchorage portion of said first stiffening element is anchored in the top by being anchored in or around one or more radially external reinforcing structures of the stiffening structure arranged in the top.

[0105] Alternatively, said radially external anchoring portion of said first stiffening element is anchored in the apex by being anchored in an elastomeric mass of said apex.

[0106] Optionally, said radially external anchorage portion of said second stiffening element is anchored in the apex by being anchored in or around one or more radially external reinforcing structures of the stiffening structure arranged in the apex.

[0107] Alternatively, said radially external anchoring portion of said second stiffening element is anchored in the apex by being anchored in an elastomeric mass of said apex.

[0108] Each internal or external radial reinforcement structure is respectively arranged within the corresponding side and / or flange or in the top; that is, arranged axially and / or radially within the internal surface and embedded in the mass of materials constituting the corresponding side and / or flange or the top. The stiffening structure passes through the internal surface to anchor itself in or around the corresponding internal radial reinforcement structure and / or through the internal surface to anchor itself in or around the external radial reinforcement structure(s).

[0109] As previously stated, the stiffening structure can be anchored in or around at least one internal and / or external radially reinforcing structure.

[0110] 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.

[0111] In particular, in the case 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.

[0112] 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.

[0113] In particular, in the case 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.

[0114] Advantageously, in embodiments comprising a first radially internal reinforcing structure arranged in the first flange and / or bead, this structure includes at least one first circumferential radially internal reinforcing element. This first circumferential radially internal reinforcing element allows the stiffening structure to be anchored in the first flange and / or bead.

[0115] Optionally, in embodiments comprising a second radially internal reinforcing structure arranged in the second flange and / or bead, this structure preferably includes at least one second circumferential radially internal reinforcing element. This second circumferential radially internal reinforcing element allows the stiffening structure to be anchored in the second flange and / or bead.

[0116] Advantageously, the first internal radially internal circumferential reinforcing element and / or the second internal radially internal circumferential reinforcing element is wound circumferentially for at least one complete turn around the axis of revolution, preferably for several complete turns around the axis of revolution. Two consecutive turns may or may not be in contact with each other.

[0117] In one embodiment, said first circumferential radially internal reinforcing element comprises a metallic wire reinforcing element.

[0118] Advantageously, said first circumferential radially internal reinforcing element comprises an assembly of a plurality of metallic monofilaments, each with a diameter between 0.15 and 0.45 mm, preferably between 0.20 and 0.40 mm. Alternatively, said first circumferential radially internal reinforcing element comprises a textile yarn reinforcing element.

[0119] Optionally, said second circumferential internal radial reinforcement element includes a metallic wire reinforcement element.

[0120] Advantageously, said second circumferential internal radial reinforcement element comprises an assembly of a plurality of metallic monofilaments, each with a diameter between 0.15 and 0.45 mm, preferably between 0.20 and 0.40 mm. Alternatively, said second circumferential internal radial reinforcement element comprises a textile yarn reinforcement element.

[0121] Advantageously, said first and / or second internal radially internal circumferential reinforcement element extends 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.

[0122] In embodiments comprising at least one radially external reinforcing structure arranged in the apex, this structure preferably includes a circumferential radially external reinforcing element. This circumferential radially external reinforcing element allows the stiffening structure to be anchored in the apex.

[0123] Advantageously, the circumferential element or each radially external reinforcement element is circumferentially wound at least one full turn around the axis of revolution, preferably several full turns around the axis of revolution.

[0124] In one embodiment, the radially external circumferential reinforcement element of the radially external reinforcement structure(s) comprises a metallic wire reinforcement element. Advantageously, the radially external circumferential reinforcement element comprises an assembly of a plurality of metallic monofilaments, each with a diameter between 0.15 and 0.45 mm, preferably between 0.20 and 0.40 mm. Alternatively, the radially external circumferential reinforcement element of the radially external reinforcement structure(s) comprises a textile wire reinforcement element.

[0125] Advantageously, the circumferential radially external reinforcement element(s) extend 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.

[0126] In some 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.

[0127] This reduces the mass of the reinforcement structure used to anchor the stiffening structure at the top and limits the over-fretching of the top, thus maintaining a regular contact area.

[0128] 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.

[0129] This improves the axial distribution of the forces exerted by the stiffening structure on the apex.

[0130] In other embodiments, the tire comprises a single radially external reinforcement structure extending continuously on each side of the tire's median plane.

[0131] Each internal radial reinforcement circumferential element and each external radial reinforcement circumferential element may be wound in various ways, as described in particular in W02022 / 200717. Of course, the tire may include several of the said first and / or second internal and / or external radial reinforcement structures.

[0132] Advantageously, the first inner radially crosslinked polymer composition layer is covered with a layer based on an adhesive composition and / or, the outer radially crosslinked polymer composition layer is covered with a layer based on an adhesive composition.

[0133] Optionally, the second inner layer of radially crosslinked polymer composition is covered with a layer based on an adhesive composition.

[0134] The adhesive composition is preferably based on a resin chosen from among aldehyde / phenol resins, polyepoxide resins, polyisocyanate resins, aromatic polyepoxy-phenolic resins and polyfunctional resins as well as mixtures of these resins.

[0135] Typically, in a tire with a crown reinforcement and a carcass reinforcement, the crown comprises a tread designed 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 into each sidewall and axially into the crown, radially within the crown reinforcement. Conventionally, the crown reinforcement includes at least one crown layer with reinforcing elements. These reinforcing elements are preferably textile or metallic wires.

[0136] In embodiments enabling the achievement of radial tire performance 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 an angle, in absolute value, of 80° to 90° with the circumferential direction of the tire. Alternatively, a variable angle of 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.

[0137] In an advantageous embodiment, the stiffening structure is not airtight to the tire's 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 within the tire. By "not airtight," it is understood that the stiffening structure is permeable to the inflation gas so that the pressure is homogeneous within the toroidal cavity at all times, and particularly during tire inflation.

[0138] 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.

[0139] Advantageously, 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.

[0140] Thus, the portions extending, on the one hand, between an inner radial anchor point and a radially outer anchor point located on the same side of the median plane, and on the other hand, between an inner radial anchor point and a radially outer anchor point located on the opposite side of the median plane, do not intersect. This limits axial buckling of the tread, i.e., axial compression of the tread, particularly under conditions of high lateral stress. Consequently, a regular contact area is maintained, and the risk of damage to the tire's crown reinforcement is reduced, notably by preventing compression of the various components of the crown reinforcement, such as the textile and metallic wire reinforcement elements.Preferably, the stiffening structure comprises a plurality of first stiffening elements distributed circumferentially in the toric cavity.

[0141] Optionally, the stiffening structure includes a plurality of second stiffening elements distributed circumferentially in the toroidal cavity.

[0142] In a first configuration of the stiffening elements, each first stiffening element forms a continuous first stiffening element that meanders at least from the first flank and / or bead through the apex. Preferably, each second stiffening element also forms a continuous second stiffening element that meanders at least from the second flank and / or bead through the apex.

[0143] This simplifies tire manufacturing and improves the robustness of the stiffening structure by eliminating the need for anchoring the ends of the stiffening element in each sidewall and / or bead and / or crown. In this configuration, a continuous stiffening element extending around the entire circumference of the tire is possible. Because this stiffening element is continuous, the transmission of forces between each sidewall and / or bead is improved, as the forces are distributed across the tire. Thus, the stiffening structure performs its function around the entire circumference of the tire.

[0144] 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.

[0145] According to a second variant of the first stiffening element configuration, each first stiffening element forms a continuous stiffening element that meanders between the first flank and / or bead and the apex. Again 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.

[0146] In a second configuration of the stiffening elements, each first stiffening element could extend from the first side and / or bead to the top and have one end in the first side and / or bead. Similarly, each second stiffening element could extend from the second side and / or bead to the top and have one end in the second side and / or bead.

[0147] In a first variation of this second configuration, each first stiffening element could extend from the first side and / or bead to the apex and have one end at the apex. Similarly, each second stiffening element could extend from the second side and / or bead to the apex and have one end at the apex.

[0148] In a second variant of this second configuration, each first stiffening element is respectively each 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.

[0149] Each stiffening element, according to one of the previously defined designs or configurations, can be characterized geometrically, in particular by its average cross-sectional area Sm. This characteristic is not necessarily identical for all stiffening elements. The average cross-sectional area 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-sectional area Sm is the constant cross-sectional area of ​​the stiffening element. The average cross-sectional area 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 average section Sm, having a diameter equal to d, has a form ratio R= l, a stiffening element having a rectangular average section Sm, having a length L and a width 1, has a form ratio R=L / 1, and a stiffening element having an elliptical average section Sm, having a major axis D and a minor axis d, has a form ratio R=D / d.

[0150] A 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 exhibits wire-like mechanical behavior, meaning it can only be subjected to tensile or compressive forces along its neutral axis. This is why a one-dimensional stiffening element is commonly 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 section Sm being substantially circular, the shape ratio R is equal to 1, therefore less than 3.

[0151] A second type of stiffening element, with an aspect ratio R of at least 3, is called 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 three 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.

[0152] The materials that can be used for each stiffening element are as described in W02022 / 200717.

[0153] 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.

[0154] These wire stiffening elements are commonly called stays. The advantage of using wire stiffening elements is that they provide a low-mass, low-hysteresis stiffening structure. Using identical wire stiffening elements ensures a homogeneous distribution of stress between them.

[0155] By textile, we mean that each wire stiffening element is non-metallic, for example, made of a material chosen from among 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.

[0156] Advantageously, in an alternative method 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 from 85° to 90° in absolute value. In another alternative method for manufacturing the tire using a more complex process but allowing for increased circumferential stiffness, each wire stiffening element extends within the toroidal cavity along a principal direction forming an angle with the circumferential direction of the tire ranging from 45° to 85° in absolute value, as explained in particular in WO2020 / 128225.

[0157] In a preferred variant, each first and second bead comprises respectively a first and second circumferential radially internal reinforcement element intended to enable 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 enable the tire to be attached to a tire mounting support.

[0158] This reduces the propagation of noise generated by the stiffening structure from the stiffening structure to the vehicle via the tire mounting bracket. The noise generated by the stiffening structure is dampened by the tire structure separating the internal radial reinforcement element from the internal radial reinforcement element designed to secure the tire to the mounting bracket located on the same side of the tire's median plane. This damping results from the fact that the internal radial reinforcement element is mechanically decoupled from the internal radial reinforcement element designed to secure the tire to the mounting bracket located on the same side of the tire's median plane.

[0159] Optionally, the first circumferential hooking element is arranged radially inside said first radially inner reinforcement structure by being wrapped circumferentially around the axis of revolution.

[0160] Optionally, the second circumferential hooking element is arranged radially inside said second radially inner reinforcement structure by being wrapped circumferentially around the axis of revolution.

[0161] Optionally, said first circumferential attachment element is wound circumferentially over at least two full turns, preferably over at least three full turns, more preferably over at least four full turns, even more preferably over at least five full turns and very preferably over at least six full turns, around the axis of revolution.

[0162] Optionally, said second circumferential attachment element is wound circumferentially over at least two full turns, preferably over at least three full turns, more preferably over at least four full turns, even more preferably over at least five full turns and very preferably over at least six full turns, around the axis of revolution.

[0163] Such a circumferential attachment element is described in particular in WO2021 / 123522A1.

[0164] Alternatively, said first internal radially reinforcing circumferential element or each first and second internal radially reinforcing circumferential element is intended to permit the attachment of the tire to a tire mounting support.

[0165] Preferably, the process for manufacturing a tire includes the use of tooling equipped with a rigid toroidal core on which the tire is manufactured.

[0166] Such a toroidal core has, around its central axis, a convex external surface called the "receiving surface" which has a shape conjugate to the internal surface of the tire and which includes for this purpose a radially external summit zone intended to receive constituent components of the top of the tire, and, on either side axially of said summit zone, a first lateral zone folded towards the central axis and intended to receive constituent components of the first sidewall and the first bead as well as a second lateral zone folded towards the central axis and intended to receive constituent components of the second sidewall and the second bead, so that the core materializes a volume, called the "reserved volume", which is delimited externally by the receiving surface and which corresponds to the cavity of the tire.

[0167] Preferably, the core has a plurality of passages which extend inside the reserved volume, under the receiving surface, and which open onto said receiving surface so that each of said passages connects the top zone of the receiving surface to one of the first and second lateral zones so that the core can receive, inside said passages, the stiffening structure designed to permanently integrate the structure of the tire and extend into the cavity of the tire by connecting the first sidewall and / or bead and the top and optionally the second sidewall and / or bead and the top.

[0168] Advantageously, the core comprises an assembly of several annular subassemblies, namely a central crown, a left ear, and a right ear, each of which is angularly divided into sectors, in azimuth around the central axis, according to an alternation of so-called "key" sectors, designed to be accessible by radially internal approach and to be removed first when disassembling the subassembly in question, and so-called "vault" sectors, supported and locked in position by the keys, and designed to become maneuverable after they have been released by the removal of the keys.

[0169] Such tooling and its use for the purpose of applying the process according to the invention are described in particular in W02022 / 200718.

[0170] The process may include an initial preparation stage, during which the tooling is prepared, notably by assembling the crown keys and arches to form the central crown and by fixing to the central crown a succession of ear keys and arches to form the left and right ears.

[0171] Advantageously, during the step of setting up said stiffening structure, at least a part of the stiffening structure is passed through one or more passage(s) of the core.

[0172] The process may include, after the step of setting up said stiffening structure, a lining step during which the other constituent components of the top, sidewalls and bead of the tire are deposited on the receiving surface, in order to build a wall of the tire.

[0173] These components preferably comprise rubber-based strips or sheets, possibly reinforced by longitudinal reinforcing threads made of textile, polymer, or metal. Other reinforcing components may be provided, such as composite strips made of fiberglass and resin.

[0174] All or part of said components may preferably be placed by winding onto the rotating core.

[0175] During the curing stage, the core and the tire carried by the core can be placed in a curing mold to vulcanize the rubber-based tire components. For this purpose, the temperature of the mold, and more specifically of the tire, is preferably raised to a value between 120°C and 200°C.

[0176] Finally, the process may include a demolding step during which the tire core is removed, leaving the stiffening structure in place within the tire cavity. Brief description of the drawings

[0177] 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:

[0178] - Figure 1 is a view of a tire in a meridian cutting plane parallel to the axis of rotation which is obtained by implementing a manufacturing process according to a first embodiment of the invention;

[0179] - Figures 2 and 3 are schematic representations of the arrangement of the stiffening structure of Figure 1 in each first and second flank and / or bead;

[0180] - Figures 4 and 5 are schematic representations of the arrangement of the stiffening structure of Figure 1 in the apex;

[0181] - Figure 6 is a representation of the manufacturing process according to the first embodiment of the invention;

[0182] - Figures 7, 8 and 9 illustrate steps in the manufacturing process according to the first example of implementation of the invention;

[0183] - Figure 10 is a view similar to that of Figure 2 of a tire obtained by implementing a manufacturing process according to a second embodiment of the invention; and

[0184] - Figure 11 is a representation similar to that of Figure 6 of the manufacturing process according to a second embodiment of the invention.

[0185] Detailed description

[0186] In the figures relating to the tire, we have represented a coordinate system X, Y, Z corresponding to the usual directions respectively axial (Y), radial (Z) and circumferential (X) of a tire.

[0187] The figures represent a tire 10 having a substantially toroidal shape around 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 represented in a new condition, that is to say, not yet having been driven on.

[0188] The tire 10 described with reference to figures 1 to 5 comprises a vertex 12 including a tread 14 intended to come into contact with a ground during rolling and a vertex reinforcement 16 extending into the vertex 12 in the circumferential direction X. The tire 10 also comprises an inner layer 18.

[0189] The tire 10 includes a top reinforcement identical to that described W02022 / 200717 comprising a working reinforcement 20 including working layers 24, 26 and a shrink-fit reinforcement 22 including a shrink-fit layer 28.

[0190] The tire 10 comprises first and second sidewalls 30A, 30B extending radially inwards from the apex 12. The second sidewall 30B is opposite the first sidewall 30A with respect to the median plane M. The tire 10 has first and second bead 32A, 32B extending radially inwards from each first and second sidewall 30A, 30B, 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. The tire 10 is provided with an internal surface 34, intended to be in contact with the tire inflation gas, and which delimits a toroidal cavity 36 for inflating the tire 10. The internal surface 34 is here supported by the inner layer 18.

[0191] The tire 10 includes first and second radially internal reinforcement structures 38A, 38B respectively arranged in each first and second bead 32A, 32B.

[0192] Each first and second radially internal reinforcement structure 38A, 38B respectively comprises at least first and second circumferential radially internal reinforcement elements 40A, 40B, respectively arranged in each first and second bead 32A, 32B.

[0193] As more clearly illustrated in Figures 2 and 3, each first and second radially internal circumferential reinforcing element 40A, 40B respectively comprises first and second metallic wire reinforcing elements, each consisting of an assembly of a plurality of metallic monofilaments. Each assembly comprises an inner layer of two elementary metallic monofilaments wound helically, for example, at a 5 mm pitch, and an outer layer of seven elementary metallic monofilaments wound helically around the inner layer, for example, at a 10 mm pitch.

[0194] As an indication, the metallic monofilaments can each have a diameter between 0.15 and 0.45 mm, and more precisely between 0.20 and 0.40 mm and here have a diameter of 0.35 mm.

[0195] Each first and second bead 32A, 32B respectively comprises a first and second circumferential internal axially gripping element 42A, 42B and a first and second circumferential external axially gripping element 43A, 43B, each here comprising a rod, and intended to allow the tire 10 to be attached to a tire mounting support 10, for example, a rim. Each first and second circumferential internal axially gripping element 42A, 42B is arranged respectively inside each first and second circumferential external axially gripping element 43A, 43B. Each first circumferential internal axially gripping element 42A is distinct from each first circumferential external axially gripping element 43A.Each second internal axially attached circumferential element 42B is distinct from each second external axially attached circumferential element 43B.

[0196] Each first and second axially internal circumferential hooking element 42A, 42B and axially external 43A, 43B is circumferentially wound over at least two full turns, preferably over at least three full turns, more preferably over at least four full turns, even more preferably over at least five full turns and very preferably over at least six full turns around the axis of revolution of the tire 10, and here over eight full turns for the first and second axially internal circumferential hooking elements 42A, 42B and over seven full turns for the first and second axially external circumferential hooking elements 43A, 43B, so as to extend respectively into the first or second bead 32A,32B radially inwards from a corresponding radially outward end to a corresponding radially inward end, defining a length of the axially concerned circumferential attachment elements.

[0197] Each first and second circumferential internal axially attached element 42A, 42B and externally axially attached element 43A, 43B is arranged radially inside respectively each first and second radially internal reinforcement structure 38A, 38B, in particular each first and second circumferential internal axially attached element 42A, 42B and externally axially attached element 43A, 43B is arranged radially inside respectively each first and second circumferential radially internal reinforcement element 40A, 40B.

[0198] Each first circumferential internal radial reinforcement element 40A is distinct from each first circumferential internal axial attachment element 42A and external axial attachment element 43A. Each second circumferential internal radial reinforcement element 40B is distinct from each second circumferential internal axial attachment element 42B and external axial attachment element 43B.

[0199] The tire 10 comprises first and second radially external reinforcement structures 44A, 44B arranged in the apex 12 and each respectively provided 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 W02022 / 200717 and shown in more detail in Figures 4 and 5. Each first and second circumferential radially internal reinforcement element 40A, 40B and external reinforcement element 46A, 46B extends along a principal direction forming with the circumferential direction X an angle less than or equal to 10°, preferably less than or equal to 5° and here substantially zero.Each first and second radially internal circumferential reinforcing element 40A, 40B and external element 46A, 46B is circumferentially wound over at least one full turn and preferably over several full turns around the axis of revolution Y.

[0200] The tire 10 comprises a carcass reinforcement 48 including a carcass layer 50 extending axially in the crown 12, radially inwardly to the crown reinforcement 16, and radially in each of the first and second sidewalls 30A, 30B and bead 32A, 32B. The crown reinforcement 16 is arranged radially between the tread 14 and the carcass reinforcement 48. The various crown layers 24, 26, 28 and carcass 50 are identical to those described in W02022 / 200717.

[0201] The carcass layer 50 is therefore arranged in each first and second flank 30A, 30B and ridge 32A, 32B and anchored in each first and second ridge 32A, 32B.

[0202] In this case, the carcass layer 50 extends axially between each first and second circumferential internal axial attachment element 42A, 42B and each first and second circumferential external axial attachment element 43A, 43B. Each first and second circumferential internal axial attachment element 42A, 42B and the axially external attachment element 43A, 43B are axially adj acent to the carcass layer 50 respectively in each first and second bead 32A, 32B.

[0203] The carcass layer 50 extends radially along each first and second circumferential internal axially anchoring element 42A, 42B and external 43A, 43B.

[0204] The tire 10 includes a stiffening structure 52 extending into the toroidal cavity 36 from the first bead 32A to the apex 12 and anchored in the first bead 32A by being anchored around the first radially internal reinforcement structure 38A. The stiffening structure 52 extends into the toroidal cavity 36 from the second bead 32B to the apex 12 and is anchored in the second bead 32B by being anchored around the second radially internal reinforcement structure 38B. The stiffening structure 52 extends into the toroidal 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 being anchored around the radially external reinforcement structures 44A, 44B.

[0205] The stiffening structure 52 comprises a plurality of stiffening elements 54 including 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.

[0206] 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.

[0207] 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.

[0208] In order to ensure optimal anchoring of the first and second stiffening elements 54A, 54B, each first and second radially internal reinforcement structure 38A, 38B, in particular each first and second circumferential radially internal reinforcement element 40A, 40B, has relatively high tensile and flexural stiffnesses.

[0209] 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 the over-fretching of the top 12 and not risk damaging the flatness of the tread 14.

[0210] Each first stiffening element 54A is anchored, in the first bead 32A, in or around the first radially internal reinforcing structure 38A. Each second stiffening element 54B is anchored in the second bead 32B, in or around the second radially internal reinforcing structure 38B.

[0211] 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 radially external reinforcing element 46A, 46B.

[0212] Each first stiffening element 54A passes through the internal surface 34 at a first radially internal anchor point 56A in the first bead 32A to anchor around the first radially internal reinforcement structure 38A and at a first radially external anchor point 58A 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.

[0213] Each second stiffening element 54B passes through the internal surface 34 at a second radially internal anchor point 56B in the second bead 32B to anchor around the second radially internal reinforcement structure 38B and at a second radially external anchor point 58B 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.

[0214] 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.

[0215] 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.

[0216] 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.

[0217] The portion 544 of each second stiffening element 54B extends in the toroidal cavity 36 from the second radially internal anchor point 56B to the second radially external anchor point 58B. The radially internal anchor portion 541 of each first stiffening element 54A extends from the first radially internal anchor point 56A in the first bead 32A to anchor in or around the first radially internal reinforcing structure 38A.

[0218] 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 reinforcing structure 44A.

[0219] 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 in or around the second radially internal reinforcing structure 38B.

[0220] The radially external anchorage portion 546 of each second stiffening element 54B extends from the second radially external anchorage point 58B in the apex 12 to anchor around the second radially external reinforcing structure 44B.

[0221] Each first stiffening element 54A forms a first continuous stiffening element which meanders at least from the first bead 32A through the top 12 and each second stiffening element 54B forms a second continuous stiffening element which meanders at least from the second bead 32B through the top 12. More precisely, the first and second stiffening elements 54A, 54B form a continuous stiffening element 54 which extends continuously from the first bead 32A to the second bead 32B through the top 12 so as to meander from the first bead 32A to the second bead 32B.

[0222] 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 portions 543, 544 do not intersect in the toric cavity 36.

[0223] Each first and second stiffening element 54A, 54B is partially wrapped around each first and second circumferential internal radial reinforcement element 40A, 40B respectively.

[0224] Each radially internal anchorage portion 541, 542 extends at least partially axially inside each first and second circumferential axially internal anchoring element 42A, 42B.

[0225] With reference to Figure 2, the tire 10 comprises a first layer of a first radially internal crosslinked polymer composition 60A interposed between the stiffening structure 54A and the first radially internal reinforcement structure 40A, and more precisely between the radially internal anchoring portion 541 and the first radially internal reinforcement structure 38A and even more precisely between the radially internal anchoring portion 541 and the first circumferential radially internal reinforcement element 40A.

[0226] The first layer of radially cross-linked polymer composition 60A extends from the first stiffening element 54A to the first circumferential radially cross-linked reinforcement element 40A, in contact with the stiffening structure 52 and the first radially cross-linked reinforcement structure 38A, more precisely with the radially cross-linked anchor portion 541 and the first radially cross-linked reinforcement structure 38A, and even more precisely with the radially cross-linked anchor portion 541 and the first circumferential radially cross-linked reinforcement element 40A. The tire 10 also includes a first intermediate radially cross-linked polymer composition 64A interposed between the stiffening structure 52 and the first layer of radially cross-linked polymer composition 60A.

[0227] With reference to Figure 3, similarly, the tire 10 comprises a second layer of radially crosslinked inner polymer composition 60B interposed between the stiffening structure 52 and the second radially inner reinforcement structure 38B, more precisely between the radially inner anchoring portion 542 and the second radially inner reinforcement structure 38B and even more precisely between the radially inner anchoring portion 542 and the second circumferential radially inner reinforcement element 40B.Thus, there is no direct contact between the stiffening structure 52 and the second radially internal reinforcement structure 38B, more precisely between the radially internal anchoring portion 542 and the second radially internal reinforcement structure 38B and even more precisely between the radially internal anchoring portion 542 and the second circumferential radially internal reinforcement element 40B.

[0228] The second layer of radially crosslinked polymer composition 60B extends from the second stiffening element 54B to the second radially internal circumferential reinforcing element 40B, being in contact with the stiffening structure 52 and the second radially internal reinforcing structure 38B, more precisely with the radially internal anchoring portion 542 and the second radially internal reinforcing structure 38B, and even more precisely with the radially internal anchoring portion 542 and the second radially internal circumferential reinforcing element 40B.

[0229] The tire 10 also includes a second radially internal intermediate layer 64B of a second radially internal cross-linked polymer composition interposed between the stiffening structure 52 and the second layer of radially internal cross-linked polymer composition 60B. With reference to Figure 4, similarly, the tire 10 includes a first layer of radially external cross-linked polymer composition 62A interposed between the stiffening structure 52 and the first radially external reinforcement structure 44A, more precisely between the radially external anchoring portion 545 and the first radially external reinforcement structure 44A, and even more precisely between the radially external anchoring portion 545 and the first circumferential radially external reinforcement element 46A.Thus, there is no direct contact between the stiffening structure 52 and the first radially external reinforcement structure 44A, more precisely between the radially external anchoring portion 545 and the first radially external reinforcement structure 44A and even more precisely between the radially external anchoring portion 545 and the first circumferential radially external reinforcement element 46A.

[0230] The first layer of radially external crosslinked polymer composition 62A extends from the first stiffening element 54A to the first radially external circumferential reinforcing element 46A, being in contact with the stiffening structure 52 and the first radially external reinforcing structure 44A, more precisely with the radially external anchoring portion 545 and the first radially external reinforcing structure 44A, and even more precisely with the radially external anchoring portion 545 and the first radially external circumferential reinforcing element 46A.

[0231] The tire 10 also includes a first radially outer intermediate layer 66A of a first radially outer crosslinked polymer composition interposed between the stiffening structure 52 and the first layer of radially outer crosslinked polymer composition 62A.

[0232] With reference to Figure 5, similarly, the tire 10 further comprises a second layer of radially external crosslinked polymer composition 62B interposed between the stiffening structure 52 and the second radially external reinforcement structure 44B, more precisely between the radially external anchoring portion 546 and the second radially external reinforcement structure 44B and even more precisely between the radially external anchoring portion 546 and the second circumferential radially external reinforcement element 46B.Thus, there is no direct contact between the stiffening structure 52 and the second radially external reinforcement structure 44B, more precisely between the radially external anchoring portion 546 and the second radially external reinforcement structure 44B and even more precisely between the radially internal anchoring portion 546 and the second circumferential radially external reinforcement element 46B.

[0233] The second layer of radially external crosslinked polymer composition 62B extends from the second stiffening element 54B to the second radially external circumferential reinforcing element 46B, being in contact with the stiffening structure 52 and the second radially external reinforcing structure 44B, more precisely with the radially external anchoring portion 546 and the second radially external reinforcing structure 44B, and even more precisely with the radially external anchoring portion 546 and the second radially external circumferential reinforcing element 46B.

[0234] The tire 10 also includes a second radially outer intermediate layer 66B of a second radially outer crosslinked polymer composition interposed between the stiffening structure 52 and the second layer of radially outer crosslinked polymer composition 62B.

[0235] In the example shown, each first and second layer of inner radially crosslinked polymer composition 60A, 60B and each first and second layer of outer radially crosslinked polymer composition 62A, 62B form an encapsulating sheath around each first and second circumferential inner radially reinforcing element 40A, 40B and each first and second circumferential outer radially reinforcing element 44A, 44B. The diameter of each sheathed first and second circumferential inner radially reinforcing element 40A, 40B and each sheathed first and second circumferential outer radially reinforcing element 44A, 44B is greater than or equal to 1.40 mm, and here equal to 1.50 mm. The encapsulation sleeve has a sleeve thickness within a range of 0.05 mm to 2.0 mm, preferably from 0.10 mm to 0.50 mm.

[0236] Each first and second layer of the inner radially crosslinked polymer composition 60A, 60B and each first and second layer of the outer radially crosslinked polymer composition 62A, 62B comprise a composition based on a diene elastomer and a crosslinking system, in this case a sulfur vulcanization system. Such compositions are well known to those skilled in the art and are, for example, described in WO2021074539.

[0237] Figure 6 schematically represents a manufacturing process for tire 10.

[0238] This process is preferably implemented using tooling (not shown) which is intended for the manufacture of a toroidal tire and which is equipped with a rigid toroidal core on which the tire 10 is manufactured. This tooling is, for example, identical to that described in W02022 / 200718. The core comprises a central ring, a left ear, and a right ear, which are each angularly divided into sectors, in azimuth around the central axis, according to an alternation of sectors called "keys", and sectors called "archs".

[0239] The core comprises, around its central axis, an external convex surface called the "receiving surface" which has a shape conjugate to the internal surface 34 of the tire 10 and which includes for this purpose a radially external summit area intended to receive constituent components of the summit 12 of the tire 10, and, on either side axially of the summit area, a first lateral area folded towards the central axis and intended to receive constituent components of the first sidewall 30A and the first bead 32A as well as a second lateral area folded towards the central axis and intended to receive constituent components of the second sidewall 30B and the second bead 32B, so that the core materializes a volume, called the "reserved volume", which is delimited externally by the receiving surface and which corresponds to the toric cavity 36 of the tire 10.The core comprises a plurality of passages which extend within the reserved volume, below the receiving surface, and which open onto the receiving surface so that each of the passages connects the apex area of ​​the receiving surface to one of the first and second lateral areas.

[0240] We start with an initial step S0 of tooling preparation during which we assemble the crown keys and arches to form the central crown, then we fix the ear keys and arches to the central crown to form the left and right ears.

[0241] A subsequent S1B step involves applying a first layer of the first radially crosslinkable polymer composition 60A so as to at least partially cover the first radially crosslinkable polymer structure 38A. During a subsequent S1B step, a second layer of the second radially crosslinkable polymer composition 60B is also applied so as to at least partially cover the second radially crosslinkable polymer structure 38B. During subsequent S2A and S2B steps, first and second layers of the first and second radially crosslinkable polymer compositions 62A and 62B, respectively, are also applied so as to at least partially cover each first and second radially crosslinkable polymer structure 44A and 44B, respectively.

[0242] In particular, a first sheath of the first radially crosslinkable polymer composition 60A is formed around the first radially crosslinkable reinforcing circumferential element 40A. A second sheath of the second radially crosslinkable polymer composition 60B is also formed around the second radially crosslinkable reinforcing circumferential element 40B. First and second sheaths of each first and second radially crosslinkable polymer composition 62A and 62B are also formed around each first and second radially crosslinkable reinforcing circumferential element 46A and 46B, respectively. The formation of the first and second sheaths is, for example, identical to that described in W02010 / 01241 or WO2017 / 050780.

[0243] Each SIA, S IB, S2A, S2B laying step is carried out outside the first and second bulge 32A, 32B and the vertex 12.

[0244] A crosslinking step S3A is then performed, during which at least partial crosslinking of the first layer of the first radially crosslinkable inner polymer composition 60A is carried out. During a step S3B, at least partial crosslinking of the second layer of the second radially crosslinkable inner polymer composition 60B is carried out. During steps S4A and S4B, at least partial crosslinking of each first and second layer of each first and second radially crosslinkable outer polymer composition 62A and 62B, respectively, is carried out.

[0245] Referring to Figure 7, a step S5A is then performed to install the first internal radially oriented circumferential reinforcement element 40A, sheathed in the first bead 32A. A step S5B is also performed to install the second internal radially oriented circumferential reinforcement element 40B, sheathed in the second bead 32B. Steps S6A and S6B are also performed to install each of the first and second external radially oriented circumferential reinforcement elements 46A and 46B, sheathed in the apex 12.

[0246] Then, with reference to Figure 8, a step S7A is carried out, placing a first intermediate layer of a first radially internal raw polymer composition 64A interposed between the stiffening structure 52 and the first layer of the first radially internal partially crosslinked polymer composition 60A. A step S7B is also carried out, placing a second intermediate layer of a second radially internal raw polymer composition interposed between the stiffening structure 52 and the second layer of the first radially internal partially crosslinked polymer composition 60B.Steps S8A, S8B are also carried out to place a first and second intermediate layer respectively of first and second radially external raw polymer composition interposed between the stiffening structure 52 and respectively each first and second layer of first and second radially external partially crosslinked polymer composition 62A, 62B.

[0247] With reference to figure 9, a step S9 is then carried out to set up the stiffening structure 52 in each first and second bead 32A, 32B as well as in the apex 12.

[0248] Step S9 is performed such that the first layer of the first internal radially crosslinked polymer composition 60A is interposed between the stiffening structure 52 and the first internal radially reinforcing structure 38A. Step S9 is performed such that the second layer of the second internal radially crosslinked polymer composition 60B is interposed between the stiffening structure 52 and the second internal radially reinforcing structure 38B. Step S9 is also performed such that each first and second layer of the external radially crosslinked polymer composition 62A, 62B is interposed between the stiffening structure 52 and, respectively, each first and second external radially reinforcing structure 44A, 44B.

[0249] In particular, during step S9, the first and second stiffening elements 54A, 54B are passed through each passage of the core. More specifically, the first and second stiffening elements 54A, 54B are passed through each passage of the core so that the first and second stiffening elements 54A, 54B form a continuous stiffening element 54 which extends continuously from the first bead 32A to the second bead 32B, passing through the apex 12 and winding from the first bead 32A to the second bead 32B.

[0250] Next, a packing step S 10 is carried out during which the other constituent components of the top 12, the sides 30A, 30B and the ridges 32A, 32B of the tire 10 are deposited on the receiving surface, in order to construct a wall of the tire 10. Next, a baking step SI 1 is carried out during which the core and the tire 10 carried by the core are placed in a baking mold, in order to crosslink, here by vulcanization, the components of the tire 10 based on a diene elastomer and a crosslinking system, here a vulcanization system.Here, during the SU steps, the complete crosslinking of the first and second layers of first and second partially radially crosslinked inner polymer compositions 60A, 60B and outer polymer compositions 62A, 62B is carried out, as well as the complete crosslinking of the first and second intermediate layers of first and second raw radially inner polymer compositions 64A, 64B and outer polymer compositions 66A, 66B.

[0251] Finally, a demolding step S 12 is carried out during which the core of the tire 10 is released, leaving the first and second stiffening elements 54A, 54B in place in the toroidal cavity 36 of the tire 10.

[0252] We will now describe, with reference to Figures 10 and 11, a tire manufactured by a process according to a second embodiment of the invention. Elements analogous to those of the first embodiment are designated by identical reference numerals.

[0253] Unlike the first embodiment example, the first layer of radially crosslinked inner polymer composition 60A of the tire in Figure 10 forms a band of crosslinked polymer composition interposed between the stiffening structure 52 and the first radially inner reinforcement structure 40A.

[0254] The tire according to this second embodiment may also include cross-linked polymer composition strips interposed between the stiffening structure 52 and the second radially internal reinforcement structure 40B, as well as interposed between the stiffening structure 52 and each first and second radially external reinforcement structure 44A, 44B, and whose characteristics will be deduced mutatis mutandis from those of the cross-linked polymer composition strip interposed between the stiffening structure 52 and the first radially internal reinforcement structure 40A.

[0255] The process illustrated in Figure 1 differs from the process illustrated in Figure 6 in that, after the initial tooling preparation step S0, a step S5A' is performed to place the first radially internal reinforcement structure 40A in the first bead 32A and a step S5B' to place the second radially internal reinforcement structure 40B in the second bead 32B. After the initial tooling preparation step S0, a step S6A', S6B' is also performed to place each first and second radially external reinforcement structure 44A, 44B respectively in the apex.

[0256] Next, a step SI A' is performed to apply the first layer of the first internal radially crosslinkable polymer composition 60A. A step S 1B' is also performed to apply the second layer of the second internal radially crosslinkable polymer composition 60B. Steps S2A' and S2B' are then performed to apply the first and second layers of each first and second external radially crosslinkable polymer composition 62A and 62B.

[0257] Unlike the first embodiment, a first band of the first radially crosslinkable polymer composition is applied in the innermost position, as well as a second band of the second radially crosslinkable polymer composition in the innermost position. The first and second bands of the first and second radially crosslinkable polymer compositions are also applied in the outermost positions.

[0258] A step S3A' is then performed, involving at least partial crosslinking of the first band of the first radially crosslinkable inner polymer composition 60A. A step S3B' is also performed, involving at least partial crosslinking of the second band of the second radially crosslinkable inner polymer composition 60B. Steps S4A' and S4B' are then performed, involving at least partial crosslinking of each first and second band of each first and second radially crosslinkable outer polymer composition 62A and 62B.

[0259] We then carry out the steps S7A, S7B, S8A, S8B, S9, S10, SU and S12 described previously.

[0260] The invention is not limited to the embodiments described above.

[0261] Tire manufacturing processes may be envisaged comprising the first and second layers of radially cross-linked polymer composition 60A, 60B interposed between said stiffening structure 52 and each first and second radially cross-linked reinforcement structure 38A, 38B, but without any layer of radially cross-linked polymer composition 62A, 62B interposed between the stiffening structure 52 and the radially cross-linked reinforcement structures 44A, 44B. Tires may be envisaged comprising the first and second layers of radially cross-linked polymer composition 62A, 62B, but without any first and second layers of radially cross-linked polymer composition 60A, 60B interposed between the stiffening structure 52 and each first and second radially cross-linked reinforcement structure 38A, 38B.It may also be possible to consider tires comprising a first layer of internal radially crosslinked polymer composition 60A but no second layer of internal radially crosslinked polymer composition 60B.

[0262] It may be possible to consider processes not including steps S7A, S7B, S8A, S8B.

[0263] It will be possible to consider tires having a carcass reinforcement anchored in each first and second bead by a winding of at least one layer of carcass around first and second radially internal circumferential reinforcement elements intended to allow the tire to be attached to a tire mounting support.

[0264] It may be envisaged to combine the features of the invention described above with anchoring elements as described in application filed under number FR23 15326 and / or with a sealing layer as described in application filed under number FR23 15327 or the absence of a sealing layer as described in FR23 15327 and / or main and supplementary stiffening elements as described in application filed under number FR23 15325 and / or inner and outer layers as described in application filed under number FR23 15328 and / or with an anchoring of the radially inner portion of the stiffening elements as described in application filed under number FR2401572 and / or with an irregular circumferential distribution of the stiffening elements as described in application filed under number PCT / FR2024 / 050548 filed in the name of the applicant of the present application.

Claims

58 DEMANDS 1. A method for manufacturing a tire (10) comprising: - a vertex (12), first and second flanks (30A, 30B) each extending radially inwards from the vertex, first and second ridges (32A, 32B) respectively extending radially inwards from the first and second flanks (30A, 30B) - an internal surface (34) delimiting a toroidal cavity (36) for inflating the tire (10), the tire (10) having a substantially toroidal shape around an axis of revolution; - 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), said stiffening structure (52) being anchored at least in the first flank (30A) and / or bead (32A) and / or the apex (12), said stiffening structure (52) being anchored in or around a first radially internal reinforcement structure (38A) of the tire (10) arranged in the first flank (30A) and / or bead (32A) and / or in or around one or more radially external reinforcement structure(s) (44A) arranged in the apex (12), the tire (10) comprising: - a first layer of a first radially crosslinked internal polymer composition (60A) interposed between said stiffening structure (52) and said first radially internal reinforcing structure (38A) and / or - a layer of an external radially crosslinked polymeric composition (62A) interposed between said stiffening structure (52) and said or one of said external radially reinforcing structure(s) (44A); the process comprising the following steps: - a step (SIA; SI A') of applying a first layer of a first radially crosslinkable polymeric composition inward so as to at least partially cover said first 59 radially internal reinforcing structure (38A) and / or a step (S2A, S2B; S2A', S2B') of laying a layer of a radially external crosslinkable polymeric composition so as to cover at least part of said or one of said radially external reinforcing structure(s) (44A); - a step (S3 A ; S3A' ) of at least partial crosslinking of said first layer of the first radially inner crosslinkable polymer composition and / or a step of at least partial crosslinking (S4A, S4B, S4A' , S4B ' ) of said layer of said radially outer crosslinkable polymer composition; - a step (S9) of placing said stiffening structure (52) in the first flank (30A) and / or bead (32A) and the top (12) such that said first layer of the first at least partially radially crosslinked inner polymer composition is interposed between said stiffening structure (52) and said first radially inner reinforcing structure (38A), and / or such that said layer of said at least partially radially crosslinked outer polymer composition is interposed between said stiffening structure (52) and said or one of said radially outer reinforcing structure(s) (44A); and - subsequent to the step (S3A; S3A') of at least partial crosslinking of said first layer of the first radially crosslinkable inner polymer composition and / or to the step (S4A, S4B, S4A', S4B') of at least partial crosslinking of said layer of said radially crosslinkable outer polymer composition, and subsequent to the step (S9) of setting up said stiffening structure (52), a step (SU) of curing the tire (10).

2. A method according to the preceding claim, wherein said stiffening structure (52) extends continuously into the toroidal cavity (36) from at least the second flank (30B) and / or bead (32B) to at least the apex (12), said stiffening structure (52) being anchored at least in the second flank (30B) and / or bead (32B), said stiffening structure (52) being anchored in or around a second radially internal reinforcing structure (38B) of the 60 pneumatic (10) arranged in the second sidewall (30B) and / or bead (32B), the pneumatic (10) comprises a second layer of a second radially cross-linked polymer composition (60B) interposed between said stiffening structure (52) and said second radially inner reinforcing structure (40B); the method comprising the following steps: - a step (S IB; S 1B ' ) of laying a second layer of a second radially internal crosslinkable polymer composition so as to cover at least part of said second radially internal reinforcing structure (38B); - a step (S3B; S3B') of at least partial crosslinking of said second layer of the second radially inner crosslinkable polymer composition; - a step (S9) of placing said stiffening structure (52) in the second flank (30B) and / or bead (32B) and the top (12) such that said second layer of the second at least partially radially crosslinked inner polymer composition is interposed between said stiffening structure (52) and said second radially inner reinforcing structure (38B), and - subsequent to the step of (S3B; S3B') of at least partial crosslinking of said second layer of the second radially inner crosslinkable polymer composition and subsequent to the step (S9) of setting up said stiffening structure (52), a step (SU) of curing the tire (10).

3. A method according to any one of the preceding claims, wherein the stiffening structure (52) extending in the toroidal cavity (36) from at least the first flank (30A) and / or bead (32A) to at least the apex (12) being anchored in the apex (12), and extending in the toroidal cavity from at least the second flank (30B) and / or bead (32B) to at least the apex (12) being anchored in the apex, said stiffening structure (52) being anchored in or around one or more radially external reinforcing structure(s) (44A) arranged in the apex (12), 61 The tire (10) comprises an outer radially crosslinked polymer composition layer (62A, 62B) interposed between said stiffening structure (52) and said or one of said outer radially reinforcing structure(s) (44A), the process comprising the following steps: - a step (S2A, S2B; S2A', S2B') of laying a layer of a radially externally crosslinkable polymeric composition so as to cover at least part of said or one of said radially external reinforcing structure(s) (44A); - a step (S4A, S4B; S4A', S4B') of at least partial crosslinking of said layer of said radially external crosslinkable polymeric composition; - a step (S9) of placing said stiffening structure (52) in the first flank (30A) and / or bead (32A) and the top (12) such that said layer of said at least partially radially crosslinked external polymer composition is interposed between said stiffening structure (52) and said or one of said radially external reinforcing structure(s) (44A), and - subsequent to the step (S4A, S4B; S4A', S4B') of at least partial crosslinking of said layer of said radially external crosslinkable polymer composition and subsequent to the step (S9) of setting up said stiffening structure (52), a step (SU) of curing the tire (10).

4. A method according to any one of claims 1 to 3, wherein said first radially inward reinforcing structure (38A) comprising a first circumferential radially inward reinforcing element (40A), the step (SIA) of laying said first layer of the first radially inward crosslinkable polymer composition comprises the formation of a first sheath of the first radially inward crosslinkable polymer composition around said first circumferential radially inward reinforcing element (40A), and / or said or one of said radially outward reinforcing structure(s) (44A) comprising a circumferential radially inward reinforcing element 62 outside (46A), the step (S2A, S2B) of laying said layer of said radially crosslinkable outer polymer composition includes the formation of a sheath of the radially crosslinkable outer polymer composition around said or one of said circumferential radially outer reinforcing element(s) (44A).

5. A method according to the preceding claim, wherein the step (S3A) of at least partial crosslinking of said first layer of the first radially inner crosslinkable polymer composition and / or the step (S4A, S4B) of at least partial crosslinking of said layer of said radially outer crosslinkable polymer composition is carried out after the step (SIA) of laying said first layer of the first radially inner crosslinkable polymer composition and / or the step (S2A, S2B) of laying said layer of said radially outer crosslinkable polymer composition.

6. A method according to the preceding claim, comprising, after the step (S3A) of at least partial crosslinking of said first layer of the first radially crosslinkable inner polymer composition and / or after the step (S4A, S4B) of at least partial crosslinking of said layer of said radially crosslinkable outer polymer composition, a step (S5A) of placing said first radially inner circumferential reinforcing element (40A) sheathed in the first flank (30A) and / or bead (32A) and / or a step (S6A, S6B) of placing said radially outer circumferential reinforcing element (46A) sheathed in the top (12).

7. A method according to any one of claims 1 to 3, wherein the step (S2A') of laying said first layer of the first radially crosslinkable inner polymeric composition comprises laying a first strip of the first radially crosslinkable inner polymeric composition, and / or the step (S2A', S2B') of laying said layer of said radially crosslinkable outer polymeric composition comprises laying a strip of the radially crosslinkable outer polymeric composition.

8. A method according to the preceding claim, comprising, before the step (SIA') of laying said first layer of the first radially crosslinkable polymer composition inside and / or before the step (S2A', S2B') of laying said layer of said radially crosslinkable polymer composition outside, a step (S5A') of placing said first radially inner reinforcing structure (38A) in the first flank (30A) and / or bead (32A) and / or a step (S6A', S6B') of placing said or one of said radially outer reinforcing structure(s) (44A) in the top (12).

9. A method according to the preceding claim, wherein the step (S3A') of at least partial crosslinking of said first layer of the first radially inner crosslinkable polymer composition and / or the step (S4A', S4B') of at least partial crosslinking of said layer of said radially outer crosslinkable polymer composition is carried out after the step (SIA') of laying said first layer of the first radially inner crosslinkable polymer composition and / or the step (S2A', S2B') of laying said layer of said radially outer crosslinkable polymer composition.

10. A method according to any one of claims 1 to 9, wherein the step (S3A; S3A') of at least partial crosslinking of said first layer of the first radially inner crosslinkable polymer composition and / or the step (S4A, S4B; S4A', S4B') of at least partial crosslinking of said layer of said radially outer crosslinkable polymer composition comprises the complete crosslinking of said first layer of the first radially inner crosslinkable polymer composition and / or of said layer of said radially outer crosslinkable polymer composition.

11. A method according to any one of claims 1 to 9, wherein the step (S3A; S3A') of at least partial crosslinking of said first layer of the first radially inner crosslinkable polymeric composition comprises the partial crosslinking of said first layer of the first polymeric composition radially crosslinkable inner and / or the step (S4A, S4B; S4A', S4B') of at least partial crosslinking of said layer of said radially crosslinkable outer polymer composition including the partial crosslinking of said layer of said radially crosslinkable outer polymer composition, the step (SI 1) of curing the tire (10) allows the complete crosslinking of said first layer of the first radially crosslinkable inner polymer composition and / or of said layer of said radially crosslinkable outer polymer composition.

12. A method according to any one of the preceding claims, comprising, prior to step (S9) of placing said stiffening structure (52) in the first flank (30A) and / or bead (32A) and the top (12), a step (S7A) of placing a first intermediate layer of a first radially internal raw polymer composition interposed between said stiffening structure (52) and said first layer of first at least partially radially crosslinked polymer composition, and / or a step (S8A, S8B) of placing an intermediate layer of a radially external raw polymer composition interposed between said stiffening structure (52) and said layer of said at least partially radially crosslinked polymer composition.

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