Tyre comprising an improved bead with three continuous filamentary reinforcing elements

Abstract

The tyre comprises axially inner (38), outer (40) and additional (42) continuous filamentary reinforcing elements each discontinuous with respect to the others and having breaking forces F1, F2, F3 and a number of complete turns N1, N2, N3, respectively. The axially outer continuous filamentary reinforcing element (40) is arranged axially between the axially inner (38) and additional (42) continuous filamentary reinforcing elements. A portion (36A) of the carcass layer (36) is arranged axially between the axially inner (38) and outer (40) continuous filamentary reinforcing elements. DEXT2 / DEXT1 < 1.00 and 0.80 ≤ (N1 x F1) / ((N2 x F2) + (N3 x F3)) ≤ 1.30.

Description

Pneumatic system including an improved bead with three continuous wire reinforcement elements

[0001] The present invention relates to a tire, preferably a tire for a passenger vehicle.

[0002] A tire, shown in a meridional cross-section in Figure 1, is known from the prior art. It has a substantially toroidal shape around an axis of revolution that is substantially coincident with the tire's axis of rotation. The tire comprises a crown, two sidewalls, and two bead ribs, each sidewall connecting each bead to the crown. The tire also includes a carcass reinforcement anchored in each bead and extending into each sidewall and radially inwardly to the crown.

[0003] Each reinforcement bead comprises an axially internal continuous wire reinforcement element arranged axially within a portion of the carcass reinforcement and an axially external continuous wire reinforcement element arranged axially outside the portion of the carcass reinforcement. Each axially internal and external continuous wire reinforcement element comprises several circumferential turns, around the axis of revolution, radially superimposed one on top of the other. Each continuous wire reinforcement element comprises a radially external free end and a radially internal free end.

[0004] To improve grip on dry surfaces, particularly when used on a racetrack, some users of this tire habitually lower the inflation pressure, sometimes even below the minimum recommended by the tire manufacturer. In these situations, which place extreme stress on the tire, each bead is subjected to extremely high forces. These forces can lead to cracking at the interface between the radially external free end of the axially external continuous wire reinforcement element and the elastomeric matrix in which it is embedded.

[0005] The invention aims to eliminate any risk of cracking.

[0006] To this end, the invention relates to a tire of substantially toroidal shape around an axis of revolution, comprising a vertex, two sidewalls, two bead sections, each sidewall connecting each bead to the vertex, the tire comprising: a carcass reinforcement comprising at least one layer of carcass anchored in each bead section, at least one continuous axially internal wire reinforcement element having a breaking strength F1 measured according to ASTM D 2969-00 and extending at least partially into one of the bead sections and comprising N1>2 complete circumferential turns around the axis of revolution radially superimposed one on top of the other, the axially internal continuous wire reinforcement element extending radially between a radially external dimension CEXT1 and a radially internal dimension CINT1, at least one axially external continuous wire reinforcement element having a breaking strength F2 measured according to ASTM D 2969-00 and extending at least partially into said bead and comprising N2>2 complete circumferential turns around the axis of revolution radially superimposed one on top of the other, the axially external continuous wire reinforcement element extending radially between a radially external dimension CEXT2 and a radially internal dimension CINT2,at least one additional axially continuous wire reinforcement element having a breaking strength F3 measured according to ASTM D 2969-00 and extending at least partially into said bead and comprising N3>1 complete circumferential turn(s) around the axis of revolution radially superimposed one on top of the other, the internal, external and additional axially continuous wire reinforcement elements being discontinuous with respect to each other, the external axially continuous wire reinforcement element being arranged axially between the internal axially continuous wire reinforcement element and the additional axially continuous wire reinforcement element, in the case where the carcass reinforcement includes a carcass layer, at least a portion of the carcass layer being arranged axially between the internal axially continuous wire reinforcement element and the external axially continuous wire reinforcement element,in the case where the carcass reinforcement comprises two carcass layers, at least portions of the carcass layers being arranged axially between the inner axially continuous wire reinforcement element and the outer axially continuous wire reinforcement element, said bead having a reference point defined as the intersection between:, - an imaginary straight line extending in a direction parallel to the average direction of the portion of the carcass layer or portions of the carcass layers arranged axially between the internal axially continuous wire reinforcement element and the external axially continuous wire reinforcement element, passing through radially internal and external extremities: - in the case of the portion of the carcass layer, the radially inner end of the portion is located at a radial dimension coinciding with the outermost radial dimension between CINT1 and CINT2, and the radially outer end of the portion is located at a radial dimension coinciding with the innermost radial dimension between CEXT1 and CEXT2; or - in the case of carcass layer portions, the radially inner end of the portions is the midpoint of the segment joining the radially inner ends of the portions, the radially outer end of the portions being the midpoint of the segment joining the radially outer ends of the portions, - each radially inner end of each portion being located at a radial side coinciding with the outermost radial side between CINT1 and CINT2; and - each radially external end of each portion being located at a radial side coinciding with the most radially internal radial side between CEXT1 and CEXT2; - an external surface of the bead, the point(s) of the axially internal continuous wire reinforcement element having the radially external dimension CEXT 1 being located at a radial distance DEXT 1 from the reference point, the point(s) of the axially external continuous wire reinforcement element having the radially external dimension CEXT2 being located at a radial distance DEXT2 from the reference point, the pneumatic being such that DEXT2 / DEXT1 < 1.00 and 0.80 < (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.30.

[0007] By shifting the radially external free end of the axially external continuous wire reinforcement element inward relative to that of the axially internal continuous wire reinforcement element—that is, so that DEXT2 / DEXT1 < 1.00—the axially external continuous wire reinforcement element, particularly its radially external free end, is moved away from an area of ​​significant bending stress. This prevents the axially external continuous wire reinforcement element, especially its radially external free end, from being subjected to bending stresses that could increase the risk of cracking.

[0008] The presence and dimensioning of the additional axially continuous wire reinforcement element compensate for the radial displacement of the free end of the axially external, radially inwardly directed wire reinforcement element, thus preserving the anchoring function of the carcass layer provided by the continuous wire reinforcement elements. Furthermore, this avoids unnecessarily oversizing the axially continuous wire reinforcement elements. external and additional relative to the internal axially continuous wire reinforcement element.

[0009] Such solutions are highly advantageous, particularly compared to conventional methods for reducing the risk of cracking, such as the use of elastomeric matrices with high crack resistance. While such elastomeric matrices may solve the problem, they degrade the tire's handling characteristics, especially its drift stiffness, due to their low modulus.

[0010] Another advantage of the invention is that, given its improved resistance to cracking, it allows for increased grip on dry surfaces. Thus, it may be possible to recommend driving at a lower pressure than the recommended pressure for a prior art tire, thereby improving dry grip. Alternatively, a tire tread compound designed to improve dry grip may be used; however, this increased grip significantly raises the risk of cracking for a prior art tire, whereas it has no such consequence for the tire according to the invention.

[0011] A complete circumferential turn is defined as a portion of the continuous wire reinforcement element that, from a reference azimuth, describes an angle of 360° around the tire's axis of revolution. Conversely, an incomplete circumferential turn describes, from a reference azimuth, an angle of less than 360° around the tire's axis of revolution. Each continuous wire reinforcement element can consist of N1, N2, and N3 complete circumferential turns without any incomplete circumferential turns, or it can consist of N1, N2, and N3 complete circumferential turns and one incomplete circumferential turn.

[0012] The radially outside dimension of a continuous wire reinforcement element is the radial dimension of the outermost radially outer point(s) of said continuous wire reinforcement element. This radially outside dimension is not necessarily the radial dimension of the outermost radial end of said continuous wire reinforcement element. Similarly, the radially inside dimension of a continuous wire reinforcement element is the radial dimension of the innermost radially inner point(s) of said continuous wire reinforcement element. This radially inside dimension is not necessarily the radial dimension of the innermost radial end of said continuous wire reinforcement element.

[0013] By discontinuous with respect to each other, we mean that the internal axially continuous wire reinforcement element and the external axially continuous wire reinforcement element are not continuous with each other, that the reinforcement element the axially continuous inner wire and the additional axially continuous wire reinforcement element are not continuous with each other and the axially continuous outer wire reinforcement element and the additional axially continuous wire reinforcement element are not continuous with each other.

[0014] The axially external continuous wire reinforcement element is arranged axially between the axially internal continuous wire reinforcement element and the additional axially continuous wire reinforcement element means that at least a portion of the axially external continuous wire reinforcement element extends between at least a portion of the axially internal continuous wire reinforcement element and at least a portion of the additional axially continuous wire reinforcement element.

[0015] At least a portion of the carcass layer is arranged axially between the inner axially continuous wire reinforcement element and the outer axially continuous wire reinforcement element means that at least a portion of the carcass layer extends between at least a portion of the inner axially continuous wire reinforcement element and at least a portion of the outer axially continuous wire reinforcement element.

[0016] According to one feature of the invention, each continuous internal, external, and additional wire reinforcement element extends radially at least partially into the bead. Thus, the radially internal dimension of each continuous internal, external, and additional wire reinforcement element lies between the radially internal and external dimensions radially delimiting the bead.

[0017] By continuous, we mean that each constituent material of the wire reinforcement element is monolithic along the length of the wire reinforcement element. Thus, for example, if the wire reinforcement element comprises an assembly of several metallic monofilaments, each metallic monofilament is monolithic and therefore uninterrupted between the two free ends of the wire reinforcement element.

[0018] A wire element is defined as an element extending longitudinally along a principal axis and having a cross-section perpendicular to the principal axis, where the largest dimension G is relatively small compared to the dimension L along the principal axis. Relatively small means that L / G is greater than or equal to 100, preferably greater than or equal to 1000. This definition covers both wire elements with a circular cross-section and wire elements with a non-circular cross-section, such as polygonal or oblong cross-sections. Preferably, each wire element has a circular cross-section.

[0019] According to a first object of the invention, when the carcass reinforcement comprises a single carcass layer anchored in each bead between the continuous wire reinforcement elements, the average direction of the portion of the carcass layer The axially arranged line between the continuous inner and outer axially oriented wire reinforcement elements is the direction of the line joining the inner and outer radial ends of said portion of the carcass layer. The inner radial end of said portion is located at a radial dimension coinciding with the outermost radial dimension of CINT1 and CINT2. The outer radial end of said portion is located at a radial dimension coinciding with the innermost radial dimension of CEXT1 and CEXT2.

[0020] According to a second object of the invention, when the carcass reinforcement comprises several carcass layers anchored in each bead between the continuous wire reinforcing elements, the average direction of the portions of the carcass layers arranged axially between the axially inner and outer continuous wire reinforcing elements is the direction of the line joining the midpoints of the segments joining the radially inner and outer ends of said portions of the carcass layers. The radially inner ends of said portions are located at a radial dimension coinciding with the outermost radial dimension of CINT1 and CINT2. The radially outer ends of said portions are located at a radial dimension coinciding with the innermost radial dimension of CEXT1 and CEXT2.

[0021] The measurement of each breaking force F1, F2, and F3 is performed according to ASTM D 2969-00. The measurement is carried out on a tensile testing machine equipped with a gripping system capable of reaching the breaking force Fm of the reinforcement element. The grippers used must allow for extension of the reinforcement element until failure occurs outside the gripper's gripping zone. Grippers with a gradual curvature are therefore preferred. The measurement consists of recording the force-elongation curve of the reinforcement element until failure occurs. The measurement is considered valid when the point of failure is located in the area between the grippers, outside the gripping zone of the reinforcement element. The breaking force corresponds to the maximum stress that the reinforcement element can withstand during the test.

[0022] Axial direction refers to the direction substantially parallel to the axis of revolution of the tire, that is, the axis of rotation of the tire.

[0023] 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).

[0024] 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.

[0025] By median plane of the tire (denoted M), we mean the plane perpendicular to the axis of rotation of the tire which is located at mid-axial distance of the two ribs and passes through the axial midpoint of the crown reinforcement.

[0026] The circumferential equatorial plane of the tire is defined as the theoretical cylindrical surface passing through the tire's equator, perpendicular to the median plane and the radial direction. The tire's equator, in a meridian plane (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions), is the axis parallel to the tire's axis of rotation 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, the distance between these two points being equal to H.

[0027] By meridian plane, we mean a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0028] The bead is the 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 secured.

[0029] 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).

[0030] In preferred embodiments of the invention, the tires are intended for passenger vehicles as defined in the European Tyre and Rim Technical Organisation (ETRTO) standard, 2024. Such a tire has a cross-section in a meridional plane characterized by a section height H and a nominal section width or bead size S as defined in the European Tyre and Rim Technical Organisation (ETRTO) standard, 2024, such that the H / S ratio, expressed as a percentage, is at most 90 and at least 20, and the nominal section width S is at least 115 mm and at most 385 mm. Furthermore, the hook diameter D, defining the diameter of the tire's mounting rim, is at least 12 inches and at most 30 inches.

[0031] In advantageous and optional embodiments, (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.20, preferably (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.10 and more preferably (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.00. Thus, a relatively high resistance to dislodging performance is ensured by the dimensioning of the additional axially continuous wire reinforcement element.

[0032] In advantageous and optional embodiments, DEXT2 / DEXT1 < 0.95, preferably DEXT2 / DEXT1 < 0.93. Thus, the axially external continuous wire reinforcement element is moved even further away from the area where bending stresses are significant.

[0033] In a first configuration, F1, F2 and F3 are such that 0.85 < F1 / F2 < 1.15, 0.85 < F2 / F3 < 1.15 and 0.85 < F3 / F1 < 1.15.

[0034] In this first configuration, the continuous internal, external, and additional axially oriented wire reinforcement elements are identical, simplifying the industrial management of the reinforcement elements. Identical wire reinforcement elements can have breaking strength values ​​that are otherwise identical, or at least very close, within the limits of industrial variability.

[0035] In this first configuration, we have advantageously and optionally N1 > N2 > N3. Preferably, 6 < N1 < 10 and / or 4 < N2 < 8 and / or 2 < N3 < 6.

[0036] In a second configuration, F1, F2 and F3 are such that: F1 / F2 is strictly less than 0.85 or is strictly greater than 1.15 and / or F2 / F3 is strictly less than 0.85 or is strictly greater than 1.15, and / or F3 / F1 is strictly less than 0.85 or is strictly greater than 1.15.

[0037] In this second configuration, at least one of the continuous axially internal, external and additional wire reinforcement elements is different from the others in order to optimize the dimensioning of these elements despite the increased complexity of the industrial management of the reinforcement elements.

[0038] In advantageous and optional embodiments, DEXT1 < 25 mm, preferably 5 mm < DEXT1 < 25 mm. This further distances the axially internal continuous wire reinforcement element, and more specifically its radially external end, from the area where bending stresses are significant.

[0039] In advantageous and optional embodiments, DEXT2 < 24 mm, preferably 8 mm < DEXT2 < 24 mm. This moves the axially external continuous wire reinforcement element, and more specifically its radially external end, away from the area where bending stresses are significant.

[0040] In advantageous and optional embodiments, the point(s) of the axially internal continuous wire reinforcement element having the radially internal dimension CINT1 being located at a radial distance DINT1 from the reference point, the point(s) of the axially external continuous wire reinforcement element having the radially internal dimension CINT2 being located at a radial distance DINT2 from the reference point, the additional axially continuous wire reinforcement element extending radially between an external radial dimension CEXT3 and an internal radial dimension CINT3, the point(s) of the additional axially continuous wire reinforcement element having the internal radial dimension CINT3 being located at a radial distance DINT3 from the reference point, DINT2 / DINT3 < 1.00 and DINT1 / DINT3 < 1.00. Thus, the additional axially continuous wire reinforcement element is not too close to the external surface of the bead in order to protect it, and more particularly its internal radial end.

[0041] In advantageous and optional embodiments, DINT3 > 10 mm, preferably 10 mm < DINT3 < 20 mm. Such a distance allows for the protection of the additional axially continuous wire reinforcement element, and more particularly its radially inner end.

[0042] In advantageous and optional embodiments, the additional axially continuous wire reinforcement element extends radially between a radially external dimension CEXT3 and a radially internal dimension CINT3, the point(s) of the additional axially continuous wire reinforcement element having the radially external dimension CEXT3 being located at a radial distance DEXT3 from the reference point, DEXT3 / DEXT2 < 1.00. Thus, the additional axially continuous wire reinforcement element is not too close to the external surface of the bead, which allows it to be protected, and more particularly its radially external end.

[0043] In advantageous and optional embodiments, DEXT3 / DEXT2 < 0.95, preferably DEXT3 / DEXT2 < 0.90. This provides even greater protection to the additional axially continuous wire reinforcement element and, more particularly, to its radially external end.

[0044] In advantageous and optional embodiments, DEXT3 / DEXT1 < 1.00, preferably DEXT3 / DEXT1 < 0.90, preferably DEXT3 / DEXT1 < 0.80. This provides even greater protection to the additional axially continuous wire reinforcement element and, more particularly, to its radially external end.

[0045] In advantageous and optional embodiments, DEXT3 < 20 mm, preferably 10 mm < DEXT3 < 20 mm. Such a distance allows for the protection of the additional axially continuous wire reinforcement element, and more particularly its radially external end.

[0046] In advantageous and optional embodiments, the point(s) of the axially internal continuous wire reinforcement element having the radially internal dimension CINT1 being located at a radial distance DINT1 from the reference point, the point(s) of the axially external continuous wire reinforcement element having the radially internal dimension CINT2 being located at a radial distance DINT2 from the point of reference, DINT1 / DINT2 < 1.00. Thus, we prevent the axially external continuous wire reinforcement element from being too close to the external surface of the bead in order to protect it, and more particularly its radially internal end.

[0047] In advantageous and optional embodiments, DINT1 > 5 mm, preferably 5 mm < DINT1 < 10 mm. Such a distance allows the continuous wire reinforcement element to be protected axially inside and, more particularly, its radially inside end.

[0048] In advantageous and optional embodiments, DINT2 > 8 mm, preferably 8 mm < DINT2 < 15 mm. Such a distance allows the continuous wire reinforcement element to be protected axially externally and, more particularly, its radially internal end.

[0049] In advantageous and optional embodiments, the axially external continuous wire reinforcement element comprising a radially external free end, the radially external free end is, at the azimuth of the radially external free end, arranged radially between: - at least a first portion of the axially external continuous wire reinforcement element, this first portion being arranged radially outside the radially external free end, and - at least a second portion of the axially external continuous wire reinforcement element, this second portion being arranged radially inside the radially external free end.

[0050] By moving the radially external free end away from areas of highest stress concentration, the risk of cracking is further reduced. Here, we characterize the fact that the radially external free end is sandwiched between two portions of the axially external continuous wire reinforcement element. An implicit consequence is that one portion of the axially external continuous wire reinforcement element intersects at least one other portion of the axially external continuous wire reinforcement element, the number of intersections depending on the positions of the first and second portions.

[0051] By free ends, we mean that the two radially inner and outer ends are not joined to each other by a joining means, for example by a sleeve.

[0052] In advantageous and optional embodiments, in order to prevent the radially external free end from being positioned on the path of another portion of the axially external continuous wire reinforcement element, which could cause instability during tire manufacturing and thus an area of ​​the element axially external continuous wire reinforcement susceptible to cracking, the first portion of the axially external continuous wire reinforcement element arranged radially outside the radially external free end and the second portion of the axially external continuous wire reinforcement element arranged radially inside the radially external free end are radially consecutive.

[0053] By radially consecutive, we mean that the first and second portions are arranged so that, at the azimuth of the free end considered, there are no other portions of the continuous axially external radially intercalated wire reinforcement element between each radially external and internal portion of the free end considered, except for the free end considered.

[0054] In advantageous and optional embodiments, the first portion of the axially external continuous wire reinforcement element arranged radially outside the radially external free end is, at the azimuth of the radially external free end, the portion most radially outside the axially external continuous wire reinforcement element.

[0055] This minimizes the number of intersections between sections of the continuous wire reinforcement element and, consequently, the local thicknesses in each tire bead. Thus, here, there is only one intersection between two axially external sections of the continuous wire reinforcement element.

[0056] In advantageous and optional embodiments, in order to ensure that the tire includes the expected number of circumferential turns over the entire circumference of the tire for the axially external continuous wire reinforcement element, the azimuth of the radially external free end of the axially external continuous wire reinforcement element and the azimuth of the radially internal free end of the axially external continuous wire reinforcement element are separated from each other by an angular gap of between 90° and 180°.

[0057] Similarly, in advantageous and optional embodiments, the azimuth of the radially outer free end of the axially inner and / or additional continuous wire reinforcement element and the azimuth of the radially inner free end of the axially inner and / or additional continuous wire reinforcement element are separated from each other respectively by an angular gap of between 90° and 180°.

[0058] Furthermore, by angularly offsetting the azimuth of the radially outer free end and the azimuth of the radially inner free end of one or more continuous wire reinforcement elements, the uniformity of the tire is improved by distributing the mass of the continuous wire reinforcement element(s).

[0059] In advantageous and optional embodiments, each axially continuous internal, external and additional wire reinforcement element comprises an assembly of several elementary metallic monofilaments.

[0060] A basic metallic monofilament is defined as a monolithic filament made entirely of one or more metals or metal alloys. Such basic metallic monofilaments are produced, for example, by a casting process followed by a wire drawing process, and possibly by a metal coating process. These basic metallic monofilaments are preferably made of steel, more preferably of pearlitic (or ferritic-pearlitic) carbon steel, hereinafter referred to as "carbon steel," or of stainless steel (by definition, steel containing at least 11% chromium and at least 50% iron). However, it is of course possible to use other steels or alloys.When carbon steel is advantageously used, its carbon content (steel weight percentage) preferably ranges from 0.05% to 1.2%, particularly from 0.5% to 1.1%. These contents represent a good compromise between the mechanical properties required for pneumatic applications and the feasibility of the individual metallic monofilaments. The metal used, whether carbon steel or stainless steel, may itself be coated with a metallic layer that improves, for example, the processing properties of the individual metallic monofilaments, or their performance properties, such as adhesion, corrosion resistance, or resistance to aging. In a preferred embodiment, each individual metallic monofilament is coated with a layer of brass (a zinc-copper alloy), zinc, or bronze.Each elementary metallic monofilament is, as described above, preferably made of carbon steel, and has a tensile strength ranging from 1000 MPa to 5000 MPa. Such tensile strengths correspond to the steel grades commonly encountered in the tire industry, namely NT (Normal Tensile), HT (High Tensile), ST (Super Tensile), SHT (Super High Tensile), UT (Ultra Tensile), UHT (Ultra High Tensile), and MT (Mega Tensile). The use of high tensile strengths potentially allows for improved reinforcement of the matrix in which the elementary metallic monofilaments are to be embedded, and a reduction in the weight of the reinforced matrix. The assembly of several elementary metallic monofilaments may be coated with a polymeric composition, for example, as described in US20160167438.

[0061] In advantageous and optional embodiments, the axially external continuous wire reinforcement element extends fully into the bead.

[0062] In order to limit the radial height of the continuous wire reinforcement element Axially external and not subjected to bending stresses likely to increase the risk of cracking, particularly at the radially external free end, the axially external continuous wire reinforcement element extends radially throughout the entire bead. In other words, the bead encompasses the entire axially external continuous wire reinforcement element. Thus, the radially internal dimension CINT2 and the radially external dimension CEXT2 are located between the radially internal and external dimensions that radially define the bead.

[0063] Each bead is radially delimited by a lower radial dimension and an upper radial dimension. The inner radial dimension, on a meridian plane, is defined by an axial line passing through the innermost axial point of the bead. The upper radial dimension, on a meridian plane, is defined by an axial line passing through the outermost radial contact point of the tire with the hook of the measuring rim as defined by ETRTO - Standards Manual 2024 when the tire is mounted unloaded and inflated to a pressure of 2.5 bar on that measuring rim.

[0064] In advantageous and optional embodiments, the continuous internal axially and / or additional wire reinforcement element extends fully into the bead.

[0065] In advantageous and optional embodiments, the carcass layer anchored in each bead extends radially in each flank and axially radially inwardly at the top.

[0066] In embodiments enabling the performance of so-called radial tires, for example as defined by ETRTO, the carcass layer comprises 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, as described, for example, in US20190152262.

[0067] In a first variant, the carcass reinforcement comprises a single layer of carcass. In this first variant, the carcass reinforcement, with the exception of this single layer, lacks any layer reinforced by wire reinforcement elements. The wire reinforcement elements of such reinforced layers excluded from the tire carcass reinforcement include metallic wire reinforcement elements and textile wire reinforcement elements. Preferably, the carcass reinforcement consists of the single layer of carcass.

[0068] In this first variant, at least a portion of the single layer of carcass is arranged axially between the inner axially continuous wire reinforcement element and the outer axially continuous wire reinforcement element.

[0069] In a second variant, particularly usable for tires requiring additional reinforcement of the carcass reinforcement, the carcass reinforcement comprises an inner carcass layer and an outer carcass layer arranged radially and / or axially outside the radially inner carcass layer.

[0070] In this second variant, at least a portion of the inner carcass layer and at least a portion of the outer carcass layer are arranged axially between the inner axially continuous wire reinforcement element and the outer axially continuous wire reinforcement element.

[0071] In optional and advantageous embodiments, the tire is of the "HIGH LOAD CAPACITY" type. By increasing the load index of the tire compared to the load index of a tire of the same size in its "EXTRA-LOAD" version, the tire's load capacity is increased without altering the interior space, compactness, or comfort of the vehicle on which it is used. Indeed, since the size of the tire of the invention is identical to that of the tire in its "EXTRA-LOAD" version, the tire does not take up any more space than the tire in its "EXTRA-LOAD" version. A "HIGH LOAD CAPACITY" tire may bear a distinctive marking to differentiate it from its "STANDARD LOAD" and "EXTRA-LOAD" versions, for example, a marking of the type HL (for HIGH LOAD) or XL+ (for EXTRA LOAD+).Such marking is notably disclosed in the ETRTO 2021 standard manual, page 3 of the General Notes - Passenger Car Tyres section, to designate "HIGH LOAD CAPACITY" type tyres. Examples of dimensions are also disclosed in the ETRTO 2021 standard manual, page 44, paragraph 9.1 of the Passenger Car Tyres - Tyres with metric designation section. A HIGH LOAD CAPACITY type tyre can be characterized by its load index LI such that LI > Ll'+1, where LI' is the load index of an "EXTRA LOAD" tyre of the same size, according to the ETRTO 2021 standard manual. The load index Ll' is the load index of an "EXTRA-LOAD" tyre of the same size, i.e., the same nominal section width, the same nominal aspect ratio, the same construction (R and ZR being considered identical), and the same nominal rim diameter.The load index Ll' is given by the ETRTO 2021 standard manual, specifically in the section entitled Passenger Car Tyres - Tyres with Metric Designation, pages 22 to 43. Depending on the size, we will have LI=LI'+1, LI=LI'+2, LI=LI'+3 or even LI=LI'+4. In most embodiments, Ll'+1 < Ll <. LI'+4, and even LI'+2 < Ll < LI'+4.

[0072] In order to manufacture the tire according to the invention, it may be possible in particular to carry out a process using a rigid non-deformable support of substantially toroidal shape around the axis of revolution of the support, for example as described in W003 / 101713, EP1094930, EP1463627 or EP0976535.

[0073] The invention and its advantages will be readily understood in light of the detailed description and non-limiting examples of embodiment that follow, as well as Figures 1 to 9 relating to these examples, in which: Figure 1 is a view in the meridian plane of a tire according to the prior art, Figure 2 is a view similar to that of Figure 1 of a tire according to a first embodiment of the invention in a plane of cut including the azimuth AzO of Figure 3, Figure 3 is a view of a continuous axially external wire reinforcement element of the tire of Figure 2, Figure 4 is a detailed view of part IV of Figure 3, Figure 5 is a detailed view of the bead of the tire of Figure 2, Figures 6 and 7 are views similar to those of Figures 2 and 5 of a tire according to a second embodiment of the invention,Figure 8 is a view similar to that of Figures 2 and 6 of a tire according to a third embodiment of the invention, and Figure 9 is a view similar to that of Figures 2, 6 and 8 of a tire according to a fourth embodiment of the invention.

[0074] 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.

[0075] Figure 3 shows a tire according to the invention, designated by the general reference numeral 10. The tire 10 has a substantially toroidal shape around an axis of revolution A substantially parallel to the axial direction Y. The tire 10 is intended for a passenger vehicle and has dimensions HL275 / 35ZR21 (105Y). In the various figures, the tire 10 is shown in its new condition, i.e., having not yet been driven on.

[0076] The tire 10 includes a crown 12 comprising a tread 14 intended to come into contact with the ground during rolling and a crown reinforcement 16 extending into the crown 12 in the circumferential direction X. The tire 10 also includes a sealing layer 18 for an inflation gas intended to Defining a closed internal cavity with a tire mounting support 10 once the tire 10 is mounted on the mounting support, for example a rim. The sealing layer 18 is butyl-based.

[0077] The top reinforcement 16 includes a working reinforcement 20 and a shrinkage reinforcement 22.

[0078] The working reinforcement 16 comprises at least one working layer and here comprises two working layers 24, 26. The radially inner working layer 24 is arranged radially inside the radially outer working layer 26.

[0079] The shrink frame 22 includes at least one shrink layer and here includes a shrink layer 28.

[0080] The top reinforcement 16 is radially surmounted by the tread 14. The shrinkage reinforcement 22, here the shrinkage layer 28, is arranged radially outside the working reinforcement 20 and is therefore radially interposed between the working reinforcement 20 and the tread 14. Preferably, the shrinkage reinforcement 22 may be considered to have an axial width at least as large as the axial width of the working reinforcement 20 and, in this case, in the embodiment illustrated in Figure 2, the shrinkage reinforcement 22 has an axial width greater than the axial width of the working reinforcement 20.

[0081] The tire 10 comprises two sidewalls 30 extending radially inwards from the apex 12. The tire 10 further comprises two beads 32 radially inwards from the sidewalls 30. Each sidewall 30 connects each bead 32 to the apex 12.

[0082] Each bead 32 is radially delimited by a lower radial dimension R0 and an upper radial dimension R1. Each bead has an external surface 33 in contact either with a mounting support or with the inflation gas of the internal cavity when the tire 10 is mounted on the mounting support.

[0083] The tire 10 includes a carcass reinforcement 34 anchored in each bead 32. The carcass reinforcement 34 extends radially in each sidewall 30 and axially radially inwardly at the crown 12. The crown reinforcement 16 is arranged radially between the tread 20 and the carcass reinforcement 34. The carcass reinforcement 34 comprises at least one carcass layer and here comprises a single carcass layer 36. In this case, the carcass reinforcement 34 consists of the single carcass layer 36.

[0084] Each working layer 24, 26, shrink-fit layer 28, and frame layer 36 comprises an elastomeric matrix in which one or more wire reinforcement elements of the corresponding layer are embedded. Thus, each working layer 24, 26 comprises, respectively, wire reinforcement elements, and the shrink-fit layer 28 comprises elements wire reinforcement of the frame and the carcass layer 36 includes wire reinforcement elements of the carcass.

[0085] The wire reinforcement elements for the reinforcement are textile and are circumferentially helically wound along a principal direction forming, with the circumferential direction X of the tire 10, an angle, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°. The wire reinforcement elements for the working layer are metallic and extend substantially parallel to each other within each working layer 24, 26 along principal directions forming, with the circumferential direction X of the tire 10, angles of opposite orientations between the two working layers 24, 26 and, in absolute value, strictly greater than 10°, preferably ranging from 15° to 50° and more preferably ranging from 25° to 45°.The carcass reinforcement wire elements are textile and extend along a principal direction forming an angle with the circumferential direction X of the tire 10, in absolute value, greater than or equal to 60°, preferably ranging from 80° to 90° and here substantially equal to 90°. Each reinforcement wire element of the girth and carcass is, for example, identical to those described in applications WO2021250331, WO2022074341 or WO2022069819.

[0086] The tire 10 includes an axially internal continuous wire reinforcement element 38, an axially external continuous wire reinforcement element 40 and an additional axially continuous wire reinforcement element 42. Each axially internal continuous wire reinforcement element 38, external 40 and additional 42 extends at least partially into one of the beads 32 and here entirely into the bead 32.

[0087] The axially continuous internal wire reinforcement elements 38, external 40 and additional 42 are discontinuous with respect to each other.

[0088] The axially external continuous wire reinforcement element 40 is arranged axially between the axially internal continuous wire reinforcement element 38 and the additional axially continuous wire reinforcement element 42. At least a portion of the carcass reinforcement 34 is arranged axially between the axially internal continuous wire reinforcement element 38 and the axially external continuous wire reinforcement element 40. Here, a portion 36A of the carcass layer 36 is arranged axially between the axially internal continuous wire reinforcement element 38 and the axially external continuous wire reinforcement element 40.

[0089] Each axially internal continuous wire reinforcement element 38, external 40 and additional 42 comprises respectively an axially internal wire cable 38, external 40 and additional 42 comprising an assembly of several elementary metal monofilaments comprising an assembly of an internal layer of 2 Elementary monofilaments of 0.35 mm carbon steel wound helically with a 7.5 mm pitch and an outer layer of seven elementary monofilaments of 0.35 mm carbon steel wound helically around the inner layer with a 15 mm pitch. Such cables are designated 9.35 cables according to current nomenclature and are described, for example, in US20080066843.

[0090] The axially continuous wire reinforcement elements internal 38, external 40 and additional 42 have breaking forces respectively F1, F2, F3 measured according to ASTM D 2969 - 00 such that 0.85 < F1 / F2 < 1.15, 0.85 < F2 / F3 < 1.15 and 0.85 < F3 / F1 < 1.15. Here F1=F2=F3=1980 N.

[0091] Referring to Figure 5, the axially internal continuous wire reinforcement element 38 comprises N1 complete circumferential turns greater than or equal to 2, with 6 < N1 < 10. Here, the axially internal continuous wire reinforcement element 38 comprises N1 = 8 complete circumferential turns and one incomplete circumferential turn around the axis of revolution A, radially superimposed one on top of the other. The axially internal continuous wire reinforcement element 38 extends radially between a radially external dimension CEXT1 and a radially internal dimension CINT1.

[0092] As explained previously, the radially external dimension CEXT1 is the radial dimension of the outermost radially external point(s) of the axially internal continuous wire reinforcement element 38 and is here reached at azimuth AzO at point 38A coinciding with the radially external end of the axially internal continuous wire reinforcement element 38. The radially internal dimension CINT1 is the radial dimension of the innermost radially internal point(s) of the axially internal continuous wire reinforcement element 38 and is here reached at azimuth AzO at point 38B coinciding with the radially internal end of the axially internal continuous wire reinforcement element 38.

[0093] With reference to Figures 4 and 5, the axially external continuous wire reinforcement element 40 comprises N2 complete circumferential turns greater than or equal to 2, with 4 < N2 < 8. Here, the axially external continuous wire reinforcement element 40 comprises N2 = 5 complete circumferential turns T1, T2, T3, T4, T5 and one incomplete circumferential turn T6 around the axis of revolution A, radially superimposed on one another. The axially internal continuous wire reinforcement element 38 extends radially between a radially external dimension CEXT2 and a radially internal dimension CINT2.

[0094] As explained previously, the radially external dimension CEXT2 is the radial dimension of the outermost radial point(s) of the axially external continuous wire reinforcement element 40 and does not correspond, in this case, to the radial dimension of the radially external end E1. As illustrated in Figure 4, the The radially external dimension CEXT2 is reached here at azimuth Az1 at point 40A. As explained previously, the radially internal dimension CINT2 of the axially external continuous wire reinforcement element 40 is the radial dimension of the innermost radial point(s) and corresponds, in this case, to the radial dimension of the radially internal end E2. As illustrated in Figure 4, the radially internal dimension CINT2 is reached here at azimuth Az2 at point 40B, which coincides with end E2.

[0095] Referring to Figure 4, the axially external continuous wire reinforcement element 40 comprises a radially external free end E1 and a radially internal free end E2, the radially external free end E1 being arranged radially outside the radially internal free end E2. The complete circumferential turn T1 begins at the radially external end E1, which defines a reference azimuth AzO. The complete circumferential turn T1 ends, after one complete circumferential turn around the axis of revolution A, before the azimuth AzO, from which the complete circumferential turn T2 then begins. The complete circumferential turn T2 ends, after one complete turn around the axis of revolution A, before the azimuth AzO, from which the complete circumferential turn T3 then begins.The complete circumferential revolution T3 ends, after one full revolution around the axis of revolution A, before the azimuth AzO, from which the complete circumferential revolution T4 then begins. The complete circumferential revolution T4 ends, after one full revolution around the axis of revolution A, before the azimuth AzO, from which the complete circumferential revolution T5 then begins. The complete circumferential revolution T5 ends, after one full revolution around the axis of revolution A, before the azimuth AzO, from which the incomplete circumferential revolution T6 then begins.

[0096] The radially external free end E1 of the axially external continuous wire reinforcement element 40 is, at the azimuth of the radially external free end E1, here the reference azimuth AzO, arranged radially between: - a first portion 50 of the axially external continuous wire reinforcement element 40, this first portion 50 being arranged radially outside the radially external free end E1, and - a second portion 52 of the axially external continuous wire reinforcement element 40, this second portion 52 being arranged radially inside the radially external free end E1.

[0097] In this case, the radially external free end E1 is arranged radially between the first portion 50 distributed over the complete circumferential turns T1 and T2 and the second portion 52 distributed over the complete circumferential turns T2 and T3.

[0098] The first portion 50 and the second portion 52 are radially consecutive. The first portion 50 is, at the azimuth AzO of the radially outer free end E1, the portion most radially outside of the axially external continuous wire reinforcement element 40. The end E1 is arranged radially between the first portion 50 distributed over the complete circumferential turns T1 and T2 and the second portion 52 distributed over the complete circumferential turns T2 and T3.

[0099] In figures 2 and 5 corresponding to the cross-sectional view along the cutting plane corresponding to the azimuth AzO of figure 4, the end E1 is materialized in the form of a circle filled with black.

[0100] Referring to Figure 5, the axially additional continuous wire reinforcement element 42 comprises N3 complete circumferential turns greater than or equal to 1, with 2 < N3 < 6. Here, the axially additional continuous wire reinforcement element 42 comprises N3 = 3 complete circumferential turns and one incomplete circumferential turn around the axis of revolution A, radially superimposed one on top of the other. The axially additional continuous wire reinforcement element 42 extends radially between a radially external dimension CEXT3 and a radially internal dimension CINT3.

[0101] As with the axially internal continuous wire reinforcement element 38, the radially external dimension CEXT3 is the radial dimension of the outermost point(s) of the axially additional continuous wire reinforcement element 42 and is here reached at azimuth AzO at point 42A coinciding with the radially external end of the axially additional continuous wire reinforcement element 42. The radially internal dimension CINT3 is the radial dimension of the innermost radially internal point(s) of the axially additional continuous wire reinforcement element 42 and is here reached at azimuth AzO at point 42B coinciding with the radially internal end of the axially additional continuous wire reinforcement element 42.

[0102] The values ​​of N1, N2 and N3 satisfy N1 > N2 > N3.

[0103] Portion 36A has a radially internal end V1 located at a radial dimension coinciding with the outermost radial dimension of CINT1 and CINT2, here CINT2. Portion 36A has a radially external end V2 located at a radial dimension coinciding with the innermost radial dimension of CEXT1 and CEXT2, here CEXT2.

[0104] The portion 36A of the carcass layer 36 has a mean direction defined as the direction of the line joining the radially inner ends V1 and outer ends V2 of the portion 36A.

[0105] As illustrated in Figure 5, the bead 32 has a reference point 32A defined as the intersection between: - an imaginary line Di passing through the endpoints V1, V2 and therefore extending in a direction parallel to the average direction of portion 36A, and - the external surface 33 of the bead 32.

[0106] Each point 38A, 40A, 42A, having radially external dimensions CEXT1, CEXT2, CEXT3 respectively, is located at a radial distance DEXT1, DEXT2, DEXT3 from the reference point 32A satisfying DEXT2 / DEXT1 < 1.00, DEXT3 / DEXT2 < 1.00, and DEXT3 / DEXT1 < 1.00. More precisely, DEXT2 / DEXT1 < 0.95, preferably DEXT2 / DEXT1 < 0.93, and here DEXT2 / DEXT1 = 0.91. More precisely, DEXT3 / DEXT2 < 0.95, preferably DEXT3 / DEXT2 < 0.90, and here DEXT3 / DEXT2 = 0.85. More precisely, DEXT3 / DEXT1 < 0.90, preferably DEXT3 / DEXT1 < 0.80 and here DEXT3 / DEXT1=0.78.

[0107] In particular, DEXT1 < 25 mm, preferably 5 mm < DEXT1 < 25 mm and here DEXT1=23 mm, DEXT2 < 24 mm, preferably 8 mm < DEXT2 < 24 mm and here DEXT2=21 mm, DEXT3 < 20 mm, preferably 10 mm < DEXT3 < 20 mm and here DEXT3=18 mm.

[0108] Similarly, each point 38B, 40B, 42B having respectively the radially inside dimension CINT1, CINT2, CINT3 is located respectively at a radial distance DINT1, DINT2, DINT3 from the reference point 32A satisfying DINT2 / DINT3 < 1.00 and DINT1 / DINT3 < 1.00, DINT1 / DINT2 < 1.00.

[0109] In particular, DINT1 > 5 mm, preferably 5 mm < DINT1 < 10 mm and here DINT1=8 mm, DINT2 > 8 mm, preferably 8 mm < DINT2 < 15 mm and here DINT2=11 mm, DINT3 > 10 mm, preferably 10 mm < DINT3 < 20 mm and here DINT3=13 mm.

[0110] The axially continuous internal 38, external 40 and additional 42 wire reinforcement elements also satisfy the relation 0.50 < (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.30. In addition, the pneumatic 10 satisfies the relation 0.60 < (N1 x F1) / ((N2 x F2) + (N3 x F3)), preferably 0.70 < (N1 x F1) / ((N2 x F2) + (N3 x F3)) and more preferably 0.80 < (N1 x F1) / ((N2 x F2) + (N3 x F3)). Finally, tire 10 satisfies the relation (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.20, preferably (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.10 and more preferably (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.00. Indeed, the value (N1 x F1) / ((N2 x F2) + (N3 x F3))=0.90.

[0111] Figure 6 illustrates a tire according to a second embodiment of the invention. Elements analogous to those illustrated in the preceding figures are designated by identical reference numerals.

[0112] Unlike the first embodiment, the carcass reinforcement 34 comprises two carcass layers. Here, the carcass reinforcement 34 comprises an inner carcass layer 36 and an outer carcass layer 37 arranged radially and axially outside the radially inner carcass layer 36. Similar to the radially inner carcass layer 36, the radially outer carcass layer 37 comprises carcass wire reinforcement elements extending along a principal direction that forms a common axis with the circumferential direction X of the tire. 10, an angle, in absolute value, greater than or equal to 60°, preferably ranging from 80° to 90° and here equal to 90°.

[0113] Portion 36A has a radially internal end V1i located at a radial dimension coinciding with the outermost radial dimension of CINT1 and CINT2, here CINT2. Portion 36A has a radially external end V2i located at a radial dimension coinciding with the innermost radial dimension of CEXT1 and CEXT2, here CEXT2.

[0114] The outer carcass layer 37 comprises a portion 37A arranged axially between the axially inner continuous wire reinforcement element 38 and the axially outer continuous wire reinforcement element 40. The portion 37A has a radially inner end V1e located at a radial dimension coinciding with the outermost radial dimension of CINT1 and CINT2, here CINT2. The portion 37A has a radially outer end V2e located at a radial dimension coinciding with the innermost radial dimension of CEXT1 and CEXT2, here CEXT2.

[0115] The portions 36A, 37A of the carcass layers 36, 37 have a mean direction defined as the direction of the line joining on the one hand the midpoint V1 of the segment joining the radially internal extremities V1 i, V1e of the portions 36A, 37A and on the other hand the midpoint V2 of the segment joining the radially external extremities V2i, V2e of the portions 36A, 37A.

[0116] In this second embodiment, the reference point 32A is defined as the intersection between: - an imaginary line Di passing through the extremities V1, V2 and therefore extending in a direction parallel to the average direction of the portions 36A, 37A, and - the external surface 33 of the bead 32.

[0117] Figures 8 and 9 illustrate tires according to the third and fourth embodiments of the invention. Elements analogous to those illustrated in the preceding figures are designated by identical reference numerals.

[0118] Unlike the tires in the preceding embodiments, in the tire in the third embodiment illustrated in Figure 8, the internal axially continuous wire reinforcement element 38 differs from the external axially continuous wire reinforcement elements 40 and the additional wire reinforcement element 42. Specifically, each external axially continuous wire reinforcement element 40 and the additional wire reinforcement element 42 comprise, respectively, an external axially continuous wire reinforcement element 40 and an additional wire reinforcement element 42, each comprising an assembly of several elementary metal monofilaments. The latter consists of an assembly of an inner layer of four 0.35 mm diameter carbon steel monofilaments wound helically with a 5 mm pitch and an outer layer of nine Elementary monofilaments of 0.35 mm carbon steel are helically wound around the inner layer at a 10 mm pitch. Such cables are designated 13.35 cables according to current nomenclature and are described, for example, in US20080066843. The axially internal continuous wire reinforcement element 38 comprises a 9.35 cable as described above. Thus, F1, F2, and F3 are such that F1 / F2 is strictly less than 0.85 and F3 / F1 is strictly greater than 1.15. In this case, F1 = 1980 N, F2 = F3 = 2870 N, and F1 / F2 = 0.69 and F3 / F1 = 1.45.

[0119] Unlike the tires in the preceding embodiments, in the tire in the fourth embodiment illustrated in Figure 9, the axially external continuous wire reinforcement element 40 differs from the axially internal continuous wire reinforcement elements 38 and the additional wire reinforcement element 42. In this case, each axially internal continuous wire reinforcement element 38 and the additional wire reinforcement element 42 comprises a 9.35 cable, while the axially external continuous wire reinforcement element 40 comprises a 13.35 cable. Thus, F1, F2, and F3 are such that F1 / F2 is strictly less than 0.85 and F2 / F3 is strictly greater than 1.15. In this case, F1 = 1980 N, F2 = F3 = 2870 N, and F1 / F2 = 0.69 and F2 / F3 = 1.45.

[0120] The invention is not limited to the embodiments described above.

[0121] Thus, for example, although not shown in the preceding figures, it is optionally preferred that the azimuth of the radially outer free end and the azimuth of the radially inner free end respectively of each axially inner, outer and additional continuous wire reinforcement element be separated from each other by an angular gap of between 90° and 180°, for example 120°.

Claims

- 24 - DEMANDS 1. A tire (10) of substantially toroidal shape about an axis of revolution (A), comprising a vertex (12), two sidewalls (30), and two beadings (32), each sidewall (30) connecting each bead (32) to the vertex (12), the tire (10) being characterized in that it comprises: a carcass reinforcement (34) comprising at least one carcass layer (36; 36, 37) anchored in each bead (32), at least one axially internal continuous wire reinforcement element (38) having a breaking strength F1 measured according to ASTM D 2969-00 and extending at least partially into one of the beadings (32) and comprising N1>2 complete circumferential turns about the axis of revolution (A) radially superimposed one on the other, the axially internal continuous wire reinforcement element extending radially between a radially external dimension CEXT 1 and a radially internal dimension CINT1,at least one axially external continuous wire reinforcement element (40) having a breaking strength F2 measured according to ASTM D 2969-00 and extending at least partially into said bead (32) and comprising N2>2 complete circumferential turns about the axis of revolution (A) radially superimposed one on the other, the axially external continuous wire reinforcement element extending radially between a radially external dimension CEXT2 and a radially internal dimension CINT2, at least one additional axially continuous wire reinforcement element (42) having a breaking strength F3 measured according to ASTM D 2969-00 and extending at least partially into said bead (32) and comprising N3>1 complete circumferential turn(s) about the axis of revolution (A) radially superimposed one on the other, the axially internal continuous wire reinforcement elements (38),outer (40) and additional (42) being discontinuous with respect to each other, the outer axially continuous wire reinforcement element (40) being arranged axially between the inner axially continuous wire reinforcement element (38) and the additional axially continuous wire reinforcement element (42), in the case where the carcass reinforcement (34) comprises a carcass layer (36), at least a portion (36A) of the carcass layer (36) being arranged axially between the inner axially continuous wire reinforcement element (38) and the outer axially continuous wire reinforcement element (40), in the case where the carcass reinforcement (34) comprises two carcass layers (36, 37), at least portions (36A, 37A) of the carcass layers (36, 37) being arranged axially between the inner axially continuous wire reinforcement element (38) and the outer axially continuous wire reinforcement element (40), said bead (32) having a reference point (32A) defined as the intersection between: - an imaginary straight line (Di) extending in a direction parallel to the average direction of the portion (36A) of the carcass layer (36) or portions (36A, 37A) of the carcass layers (36, 37) arranged axially between the axially internal continuous wire reinforcement element (38) and the axially external continuous wire reinforcement element (40), passing through radially internal and external ends (V1, V2): - in the case of portion (36A) of the carcass layer (36), the radially inner end (V1) of portion (36A) is located at a radial dimension coinciding with the outermost radial dimension between CINT1 and CINT2, and the radially outer end (V2) of portion (36A) is located at a radial dimension coinciding with the innermost radial dimension between CEXT1 and CEXT2; or - in the case of portions (36A, 37A) of carcass layers (36, 37), the radially inner end of portions (36A, 37A) is the midpoint of the segment joining the radially inner ends (V1 i, V1e) of portions (36A, 37A), the radially outer end of portions (36A, 37A) being the midpoint of the segment joining the radially outer ends V2i, V2e of portions (36A, 37A), - each radially inner extremity (V1 i, V1e) of each portion (36A, 37A) being located at a radial side coinciding with the outermost radial side between CINT1 and CINT2; and - each radially external end (V2i, V2e) of each portion (36A.37A) being located at a radial side coinciding with the most radially internal radial side between CEXT1 and CEXT2, - an external surface (33) of the bead, the point(s) (38A) of the axially internal continuous wire reinforcement element (38) having the radially external dimension CEXT 1 being located at a radial distance DEXT1 from the reference point (32A), the point(s) (40A) of the axially external continuous wire reinforcement element (40) having the radially external dimension CEXT2 being located at a radial distance DEXT2 from the reference point (32A), the tire being such that DEXT2 / DEXT1 < 1.00 and 0.50 < (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.

30.

2. Pneumatic (10) according to the preceding claim, in which (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.20, preferably (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.10 and more preferably (N1 x F1) / ((N2 x F2) + (N3 x F3)) < 1.

00.

3. Pneumatic (10) according to any one of the preceding claims, wherein DEXT2 / DEXT1 < 0.95, preferably DEXT2 / DEXT1 < 0.

93.

4. Pneumatic (10) according to any one of the preceding claims, wherein DEXT 1 < 25 mm, preferably 5 mm < DEXT 1 < 25 mm.

5. Pneumatic (10) according to any one of the preceding claims, wherein DEXT2 < 24 mm, preferably 8 mm < DEXT2 < 24 mm.

6. Pneumatic (10) according to any one of the preceding claims, wherein one or more points (38B) of the axially internal continuous wire reinforcement element (38) having the radially internal dimension CINT1 are located at a radial distance DINT1 from the reference point (32A), one or more points (40B) of the axially external continuous wire reinforcement element (40) having the radially internal dimension CINT2 are located at a radial distance DINT2 from the reference point (32A), the additional axially continuous wire reinforcement element (42) extending radially between a radially external dimension CEXT3 and a radially internal dimension CINT3, one or more points (42B) of the additional axially continuous wire reinforcement element (42) having the radially internal dimension CINT3 are located at a radial distance DINT3 from the reference point (32A), DINT2 / DINT3 < 1.00 and DINT1 / DINT3 < 1.

00. 7.Pneumatic (10) according to the preceding claim, in which DINT3 > 10 mm, preferably 10 mm < DINT3 < 20 mm.

8. Pneumatic (10) according to any one of the preceding claims, wherein the additional axially continuous wire reinforcement element (42) extends radially between an outer radial dimension CEXT3 and an inner radial dimension CINT3, the point(s) (42A) of the additional axially continuous wire reinforcement element (42) having the outer radial dimension CEXT3 being located at a radial distance DEXT3 from the reference point (32A), DEXT3 / DEXT2 < 1.

00.

9. Pneumatic (10) according to the preceding claim, wherein DEXT3 / DEXT2 < 0.95, preferably DEXT3 / DEXT2 < 0.

90.

10. Pneumatic (10) according to claim 8 or 9, wherein DEXT3 < 20 mm, preferably 10 mm < DEXT3 < 20 mm.

11. Pneumatic (10) according to any one of the preceding claims, wherein the point(s) (38B) of the axially continuous wire reinforcement element - 27 - interior (38) having the radially interior dimension CINT1 being located at a radial distance DINT1 from the reference point (32A), the point(s) (40B) of the axially exterior continuous wire reinforcement element (40) having the radially interior dimension CINT2 being located at a radial distance DINT2 from the reference point (32A), DINT1 / DINT2 < 1.

00.

12. Pneumatic (10) according to the preceding claim, wherein DINT1 > 5 mm, preferably 5 mm < DINT1 < 10 mm.

13. Pneumatic (10) according to claim 11 or 12, wherein DINT2 > 8 mm, preferably 8 mm < DINT2 < 15 mm.

14. Pneumatic according to any one of the preceding claims, wherein, the axially external continuous wire reinforcement element (40) comprising a radially external free end (E1), the radially external free end (E1) is, at the azimuth (AzO) of the radially external free end (E1), arranged radially between: - at least a first portion (50) of the axially external continuous wire reinforcement element (40), this first portion (50) being arranged radially outside the radially external free end (E1), and - at least a second portion (52) of the axially external continuous wire reinforcement element (40), this second portion (52) being arranged radially inside the radially external free end (E1).

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