A tire with two carcass layers.

Abstract

A pneumatic tire (11) for passenger vehicles includes a carcass reinforcement (34) fixed to each bead (32). The pneumatic tire (11) is a high load capacity type in accordance with the ETRTO Standards Manual (2021). The pneumatic tire (11) is configured such that the sidewall height H, defined as H = SW × AR / 100, where SW is the nominal section width of the tire and AR is the nominal aspect ratio of the tire, is 95≦H≦155 in accordance with the ETRTO Standards Manual (2019). The first carcass reinforcement (34) comprises a first carcass layer (36) wrapped around each circumferential reinforcing element and a second carcass layer (37), with each end (371, 372) of the second carcass layer being axially positioned between the axially inner portion (3611, 3621) and the axially outer portion (3612, 3622) of the first carcass layer (36), or axially positioned inside the axially inner portion (3611, 3621) of the first carcass layer (36).

Description

Technical Field

[0001] The present invention relates to a tire, an attachment assembly including such a tire, and a vehicle including such a tire or such an attachment assembly. A tire is understood to mean an enclosure intended to cooperate with a support element of an attachment assembly to form a cavity that can be pressurized to a pressure exceeding atmospheric pressure. The attachment assembly according to the present invention has a substantially toroidal shape structure that exhibits rotational symmetry with respect to the main axis of the attachment assembly that coincides with the main axis of the tire.

Background Art

[0002] The development of electric vehicles or hybrid vehicles has caused an increase in vehicle weight, particularly due to relatively heavy batteries that are substantially proportional to the vehicle's range. Thus, for example, in order to increase the range of an electric vehicle, it is necessary to increase the size of the battery, and as a result, the weight of the vehicle increases.

[0003] Put simply, it is estimated that today, for every 1 kilometer increase in the range of an electric motor, the vehicle weight increases by 1 kilogram. Therefore, in order to achieve a range of 500 km, it is necessary to increase the weight of an internal combustion engine vehicle by approximately 500 kg. For such a vehicle to be equipped, it is necessary to use tires that can withstand very high loads.

[0004] Prior art has shown that passenger car tires capable of withstanding relatively high loads are available. This tire is sold under the brand name MICHELIN (trademark) as the Pilot Sport 4 series, and its size is 255 / 35R18. This tire has an EXTRA LOAD (abbreviated as XL) version as defined in the ETRTO standard manual (2019), and this EXTRA LOAD version has a load index equivalent to 94. In other words, at a pressure of 290 kPa, the tire can withstand a load of 670 kg. This load capacity is relatively high compared to a tire of the same size called STANDARD LOAD (abbreviated as SL), which has a load index equivalent to 90 and can withstand a load of 600 kg at a pressure of 250 kPa.

[0005] In order to bring such tires to market, they must pass regulatory tests. For example, in Europe, tires must pass the load / speed performance tests described in Annex VII of UN / ECE Regulation 30.

[0006] However, in the EXTRA LOAD version, and even more so in the STANDARD LOAD version, such tires cannot withstand the extra load required to accommodate the battery necessary to achieve the desired driving range. Therefore, tire manufacturers needed to propose new solutions to meet this new need.

[0007] One solution that tire manufacturers consider is to use larger tires for a given vehicle, thereby enabling them to withstand greater loads. In this way, a given vehicle can be fitted with tires that have a higher load index. For example, a vehicle fitted with the aforementioned tires in the EXTRA LOAD version can be fitted with 275 / 35R19 tires in the EXTRA LOAD version, which have a load index equal to 100 and can withstand a load of 800 kg at a pressure of 290 kPa, which is far greater than a load of 670 kg.

[0008] Such an increase in tire size inevitably leads to either a reduction in the vehicle's internal space or an increase in its external bulk, both of which are undesirable from the standpoint of vehicle capacity and compactness.

[0009] Furthermore, such an increase in tire size necessitates a redesign of the vehicle chassis, which is clearly undesirable for cost reasons.

[0010] Finally, increasing tire size, particularly nominal cross-sectional width, is accompanied by increased external noise generated by the tires and increased rolling resistance, which is also undesirable in order to reduce noise pollution and vehicle energy consumption.

[0011] Thus, another solution considered by tire manufacturers is to increase the recommended tire pressure for a given size and type of tire. This is because higher tire pressure allows the tire to withstand heavier loads.

[0012] However, using relatively high recommended tire pressures inevitably results in stiffer tires, leading to a loss of comfort for vehicle occupants. This is clearly undesirable for some automakers when occupant comfort takes precedence over load capacity.

[0013] Thus, tire manufacturers decided to create a new type of tire. This new type is now known as "High Load Capacity" in the ETRTO Standard Manual (2021). This new type ensures that a tire of a given size can withstand a load significantly greater than that of an EXTRA LOAD version of the same size. For a size 255 / 35R18, a High Load Capacity tire has a load index equal to 98, indicating that it can withstand a load of 750 kg at a pressure of 290 kPa.

[0014] However, the first problem tire manufacturers encounter is that the tension on the carcass reinforcement of tires with relatively high sidewalls, i.e., sidewall heights of 95 or more, is relatively high, and this tension increases even more as the load to be withstood increases.

[0015] Furthermore, in the case of relatively tall sidewalls with a moderate height, a second problem that manufacturers encounter during tire development is energy dissipation and temperature within the structure, which can be revealed in particular by tests described in Annex VII of UN / ECE Regulation No. 30. Specifically, when the load applied to the tire was increased to simulate the addition of mass equivalent to the battery required to achieve the desired range, a significant increase in energy dissipation and a rise in sidewall temperature were observed. [Overview of the Initiative] [Problems that the invention aims to solve]

[0016] The object of the present invention is to provide a tire that can withstand greater loads than existing tires without necessarily increasing the recommended tire pressure, while reducing the tension of the tire carcass reinforcement and energy dissipation and temperature rise in the tire sidewall without sacrificing vehicle capacity, compactness, and comfort. [Means for solving the problem]

[0017] Accordingly, the subject of the present invention is a passenger car tire comprising a crown, two beads, two sidewalls, each connecting each bead to the crown, and carcass reinforcements fixed to each bead, wherein the crown comprises a crown reinforcement and a tread, the carcass reinforcements extending within each sidewall and within the crown radially inward of the crown reinforcement, and the tire is a high load capacity type in accordance with the ETRTO standard manual (2021). The tire conforms to the ETRTO standard manual (2019), where SW is the nominal section width of the tire and AR is the nominal aspect ratio of the tire. The sidewall height H, defined as H = SW × AR / 100, is such that 95 ≤ H ≤ 155. The carcass reinforcement comprises first and second carcass layers. The first carcass layer is wound around each circumferential reinforcing element of each bead, such that the axial inner portion of the first carcass layer is positioned inside the axial outer portion of the first carcass layer in the axial direction, and the axial ends of the first carcass layer are positioned outside each circumferential reinforcing element in the radial direction, and the axial ends of the second carcass layer are positioned radially inside the axial ends of the first layer, and - Between the axially inner and axially outer portions of the first carcass layer in the axial direction, -In the axial direction, on the inside of the axially inner portion of the first carcass layer, It will be placed.

[0018] According to the present invention, the tire is a tire for a passenger car. Such a tire is specified, for example, in the ETRTO (European Tire and Rim Technology Organization) Standard Manual (2019). Such a tire generally has a marking on at least one sidewall indicating the tire size in the form X / YαVUβ in accordance with the markings in the ETRTO Standard Manual (2019), where X specifies the nominal section width, Y specifies the nominal aspect ratio, α specifies the structure and may be R or ZR, V specifies the nominal rim diameter, U specifies the load index, and β specifies the speed rating.

[0019] By increasing the load index of the tire according to the present invention compared to the load index of a tire of the same size in the EXTRA LOAD version, the present invention can enhance the load-bearing capacity of the mounting assembly without changing the capacity, compactness, and comfort of the vehicle in which it is used. Specifically, since the size of the tire according to the present invention is the same as the size of the tire in the EXTRA LOAD version, the mounting assembly does not take up more space than the tire in the EXTRA LOAD version. The tire according to the present invention may be marked with distinctive markings, such as type HL (HIGH LOAD) or XL+ (EXTRA LOAD+), to distinguish it from the STANDARD LOAD version and the EXTRA LOAD version. Such markings are disclosed in particular on page 3 of the General Notes - Passenger Car Tires section of the ETRTO Standard Manual (2021). Examples of tire sizes are also disclosed on page 44 of the ETRTO Standard Manual (2021), paragraph 9.1 of the section, "Passenger Car Tires - Metric Specified Tires".

[0020] High load capacity tires can be characterized by a load index LI such that LI > LI'+1, where LI' is the load index of an extra load tire of the same size according to the ETRTO Standard Manual (2019). The load index LI' is the load index of a tire of the same size, i.e., the same nominal section width, the same nominal aspect ratio, the same construction (R and ZR are considered identical), and the same nominal rim diameter. The load index LI' is given in the ETRTO Standard Manual (2019), specifically on pages 20 to 41 of the section "Passenger car tires - Tires specified by the metric system". Depending on the size, LI = LI'+1, LI = LI'+2, LI = LI'+3, or even LI = LI'+4. In the vast majority of embodiments, LI'+1 ≤ LI ≤ LI'+4, and furthermore, LI'+2 ≤ LI ≤ LI'+4.

[0021] As explained above, tires with relatively high sidewall heights result in relatively high tension in the carcass reinforcement, particularly the portion of the carcass reinforcement that is secured to the bead by wrapping around the circumferential reinforcement elements. This is due to the relatively large volume of expansion gas they contain compared to tires with relatively low sidewall heights. This tension increases with higher loads, as is the case with high-load capacity tires. Therefore, it is essential to use two carcass layers, thereby significantly reducing the tension in each carcass layer.

[0022] By limiting the tire sidewall height to a sidewall height H such that 95 ≤ H ≤ 155, the volume of gas is reduced, and as a result, the tension of the carcass reinforcement is reduced to a reasonable level.

[0023] Furthermore, a specific arrangement of the first and second carcass layers surprisingly yields a tire with optimal energy dissipation in the sidewall and optimal operating temperature, especially under high loads and at pressures below the recommended pressure for tires of the same size in STANDARD LOAD or EXTRA LOAD versions. This is all the more surprising because the specific arrangement of the first and second carcass layers is located in one region of the tire, in this case within or near the bead, thereby reducing energy dissipation in another region of the tire away from the bead, in this case the sidewall. The inventors have found that a specific arrangement of the carcass reinforcement, namely, that each axial end of the second carcass layer is positioned axially between the axially inner and outer portions of the first carcass layer, or axially inside the axially inner portion of the first carcass layer, can reduce the tension difference between the first and second carcass layers. In fact, the smaller the difference in tension between the first and second carcass layers, the smaller the shear stress between them, and the less energy is dissipated.

[0024] In the case of a high load capacity tire with a very high sidewall height, i.e., H > 155, even if the difference in tension between the first carcass layer and the second carcass layer remains large, due to the sidewall height, it is possible to have a relatively large shear cross-sectional area that effectively dissipates energy, and the arrangement of the first and second carcass layers according to the present invention is not required.

[0025] Therefore, in a high load capacity tire having a very high sidewall height such that H > 155, since the tension at the end of the first carcass layer becomes very high, a carcass reinforcement not according to the present invention should be considered. In that case, unlike the arrangement of the present invention, each axial end of the second carcass layer is arranged axially outside the outer portion of each axial outer side of the first carcass layer. By such an arrangement of the carcass reinforcement, the tension at the end of the first carcass layer is reduced to a reasonable level.

[0026] Finally, in contrast to a tire with a relatively short sidewall, i.e., H < 95, the tire according to the present invention exhibits a relatively low compression of the carcass reinforcement due to its relatively high sidewall. Therefore, even though there are two carcass layers, the risk that the carcass reinforcement deteriorates prematurely under particularly high loads and at relatively low pressures is avoided.

[0027] Each of the first and second carcass layers is axially delimited by two axial edges of each of the first and second carcass layers, and includes a carcass fibrous reinforcing element that extends axially from one axial edge to the other axial edge of each of the first and second carcass layers.

[0028] The nominal section width SW and the nominal aspect ratio AR are indicated by size markings engraved on the sidewall of the tire in accordance with the ETRTO standard manual (2019).

[0029] The tire according to the present invention has an annular shape around an axis of rotational symmetry that substantially coincides with the tire's axis of rotation. This axis of rotational symmetry defines three directions conventionally used by those skilled in the art: axial, circumferential, and radial.

[0030] The axial direction is understood to be the direction substantially parallel to the rotational axis of the tire or mounting assembly, i.e., the axis of rotation of the tire or mounting assembly.

[0031] The circumferential direction is understood to be a direction that is substantially perpendicular to both the axial direction and the radius of the tire or mounting assembly (in other words, a direction tangent to a circle centered on the axis of rotation of the tire or mounting assembly).

[0032] The radial direction is understood to be any direction along the radius of the tire or mounting assembly, that is, any direction that intersects the axis of rotation of the tire or mounting assembly and is substantially perpendicular to that axis.

[0033] The midline of a tire (indicated by M) is understood to be a plane located midway between the two beads in the axial direction, passing through the axial center of the crown reinforcement, and perpendicular to the tire's axis of rotation.

[0034] The tire's equatorial plane is understood to be the plane passing through the tire's equator, perpendicular to the median plane and radially in the meridional section. The tire's equator is the axis in the meridional section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions) that is parallel to the tire's axis of rotation and is equidistant between the radially outermost point of the tread intended to contact the ground and the radially innermost point of the tire intended to contact a support, such as the rim.

[0035] The meridional plane is understood to be a plane that is parallel to and contains the axis of rotation of a tire or mounting assembly, and perpendicular to the circumferential direction.

[0036] "Radially inward of ~" and "radially outward of ~" are understood to mean "closer to the tire's axis of rotation than ~" and "further from the tire's axis of rotation than ~," respectively. "Axially inward of ~" and "Axially outward of ~" are understood to mean "closer to the tire's midline than ~" and "further from the tire's midline than ~," respectively.

[0037] The bead is understood to be the portion of the tire intended to allow it to be mounted to a mounting support, such as a wheel with a rim. Therefore, each bead is specifically intended to contact the flange of the rim, enabling the rim to be mounted.

[0038] The expression "between a and b" indicates a range of values ​​that extends from greater than a to less than b (i.e., excluding the endpoints a and b), whereas the expression "from a to b" indicates a range of values ​​that extends from a to b (i.e., including the exact endpoints a and b).

[0039] In a preferred embodiment, each axial end of the second carcass layer is positioned axially between the axially inner and outer portions of the first carcass layer.

[0040] In a particular preferred variant, each axial end of the first carcass layer is positioned radially inward from the tire equator, and more preferably within a radial distance of 30 mm or less from the radially inner end of each circumferential reinforcing element of each bead.

[0041] By positioning each axial end of the first carcass layer inside the tire's equator, the mass of the carcass reinforcement is significantly reduced. Furthermore, most rims currently used in passenger car tires have a J-shaped flange with a height of less than 30 mm in all cases. The highly favorable placement of each axial end within a region substantially radially corresponding to the rim flange makes it possible to mechanically protect each axial end. Specifically, if each axial end is positioned too far radially above each circumferential reinforcement element of each bead, i.e., at a radial distance of exactly more than 30 mm from the radially inner end of each circumferential reinforcement element, it will be in a flexible region of the tire that is subjected to excessively large stresses, which are very high in the case of high load capacity type tires.

[0042] Preferably, each first and second carcass layer extends within each sidewall and within the crown radially inward of the crown reinforcement.

[0043] In optional, and still advantageous, embodiments, H ≤ 130, preferably H ≤ 120, and more preferably H ≤ 110. Reducing the sidewall height reduces the tension at the ends of the first carcass layer.

[0044] Optionally, each of the first and second carcass layers is positioned along the two axial directions of the carcass layer. end It is divided in the axial direction by, and one axial direction in the axial direction end From the other axis end The tire is equipped with carcass fabric fibrous reinforcing elements that extend along the circumferential direction of the tire and along the principal direction, forming an angle in the range of 80° to 90° in absolute value.

[0045] A fibrous element is understood to be an element whose length is at least 10 times greater than the maximum dimension of its cross-section, regardless of whether it is circular, elliptical, rectangular, polygonal, or especially rectangular, square, or oval. In the case of a rectangular cross-section, the fibrous element takes the form of a strip.

[0046] A fabric is understood to mean a fibrous element comprising one or more fabric-based monofilaments optionally coated with one or more coating layers based on an adhesive composition. These fabric-based monofilaments are obtained, for example, by melt spinning, solution spinning, or gel spinning. Each fabric-based monofilament is made from an organic material, particularly a polymer material, or an inorganic material, such as glass or carbon. Polymer materials can be thermoplastic types, such as aliphatic polyamides, particularly polyamide 6,6, and polyester, particularly polyethylene terephthalate. Polymer materials can be non-thermoplastic types, such as aromatic polyamides, particularly aramid, and natural or artificial cellulose, particularly rayon.

[0047] Preferably, each carcass fabric fibrous reinforcing element comprises an assembly of at least two multifilament strands having a total count of 475 tex or less.

[0048] This is because the presence of two carcass layers allows for a reduction in the total number of thread counts of the fibrous reinforcing elements in each carcass layer, while still maintaining a carcass reinforcement with sufficient mechanical strength.

[0049] Optionally, each carcass fabric fibrous reinforcing element of each first and second carcass layer has an average diameter D1, D2 such that D1 ≤ 0.90 mm and D2 ≤ 0.90 mm, preferably D1 ≤ 0.85 mm and D2 ≤ 0.85 mm, and more preferably D1 ≤ 0.75 mm and D2 ≤ 0.75 mm.

[0050] These relatively small diameters D1 and D2 make it possible to suppress the occurrence of cracks near the edges of each first and second carcass layer. This is because the edges of each carcass fabric fibrous reinforcing element are prone to cracking, particularly due to the fact that the element lacks an adhesive composition and, as a result, does not adhere well to the adjacent base material into which it is embedded. By reducing the diameters D1 and D2, the surface area of ​​the edges is reduced, and as a result, the risk of cracking is reduced. Similarly, D1 and D2 can be optionally set so that D1 ≥ 0.55 mm and D2 ≥ 0.55 mm, preferably D1 ≥ 0.60 mm and D2 ≥ 0.60 mm.

[0051] The yarn count (or linear density) of each strand and fibrous reinforcing element is determined in accordance with ASTM standard D885 / D885M-10a (2014). The yarn count is given in tex units (weight in grams per 1000 m of product (for note), 0.111 tex is equal to 1 denier).

[0052] The diameter of each carcass fibrous reinforcing element is the diameter of the smallest circle that circumscribes the carcass fibrous reinforcing element. The average diameter is the average value of the diameters of the carcass fibrous reinforcing elements located along a 10 cm length of each carcass layer.

[0053] Each multifilament strand is selected from polyester multifilament strands, aromatic polyamide multifilament strands, and aliphatic polyamide multifilament strands, preferably selected from polyester multifilament strands and aromatic polyamide multifilament strands.

[0054] Polyester multifilament strands are understood to be multifilament strands composed of monofilaments of linear macromolecules formed by ester bonds. Polyesters are produced by polycondensation of a dicarboxylic acid or one of its derivatives with a diol through esterification. For example, polyethylene terephthalate can be produced by polycondensation of terephthalic acid and ethylene glycol. Known polyesters include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polypropylene terephthalate (PPT), or polypropylene naphthalate (PPN).

[0055] Aromatic polyamide multifilament strands are understood to be multifilament strands composed of monofilaments of linear macromolecules formed by aromatic groups linked by amide bonds, with at least 85% directly bonded to two aromatic rings. Poly(p-phenylene terephthalamide) (or PPTA) fibers, in particular, have been produced from optically anisotropic spun compositions for a very long time. Among aromatic polyamides, examples include polyallylamide (or PAA, particularly known by trade name Ixef from Solvay), poly(metaxylylene adipamide), polyphthalamide (or PPA, particularly known by trade name Amodel from Solvay), amorphous semi-aromatic polyamide (or PA6-3T, particularly known by trade name Trogamid from Evonik), or para-aramid (or poly(paraphenylene terephthalamide) or PA PPD-T, particularly known by trade name Kevlar from DuPont de Nemours, or trade name Twaron from Teijin).

[0056] Aliphatic polyamide multifilament strands are understood to be multifilament strands composed of monofilaments of linear macromolecules of polymers or copolymers that contain amide groups and lack aromatic rings, and can be synthesized by polycondensation of carboxylic acids and amines. Examples of aliphatic polyamides include nylon PA4, 6, PA6, PA6, 6 or PA6, 10, and in particular Zytel from Dupont, Technyl from Solvay, or Rilsamid from Arkema.

[0057] More preferably, the aggregate is selected from an aggregate of two polyester multifilament strands, and an aggregate of one polyester multifilament strand and one aromatic polyamide multifilament strand.

[0058] In a preferred embodiment, the tire has a nominal section width SW in the range of 225 to 315, a nominal aspect ratio in the range of 25 to 55, a nominal rim diameter in the range of 18 to 23, and a load index LI in the range of 98 to 116, preferably a nominal section width SW in the range of 245 to 315, a nominal aspect ratio in the range of 30 to 45, a nominal rim diameter in the range of 18 to 23, and a load index LI in the range of 98 to 116. As described above, the tire according to the present invention is intended to support relatively high loads, which inevitably leads to relatively severe wear compared to an EXTRA LOAD version of the same size tire. Therefore, it is particularly advantageous to use a tire with a relatively large nominal section width to reduce the pressure applied to the tread and consequently reduce wear.

[0059] Advantageously, 0.88 ≤ H / LI ≤ 0.98. Therefore, the present invention is preferably applied to tires that are expected to have relatively large deflection, since these tires have a relatively high load index for a given sidewall height, i.e., satisfy H / LI ≤ 0.98. This is made possible by a specific arrangement of carcass reinforcements, which reduces energy dissipation despite large sidewall deflection. However, if the sidewall is too short for the load index, i.e., satisfy H / LI < 0.88, the sidewall deflection results in relatively high compression of the first carcass layer, resulting in increased energy dissipation.

[0060] A particularly preferred embodiment is one in which the tire has a size and load index LI selected from the following sizes and load indices: 225 / 55R18 105, 225 / 55ZR18 105, 205 / 55R19 100, 205 / 55ZR19 100, 235 / 45R21 104, 235 / 45ZR21 104, 285 / 45R22 116, 285 / 45ZR22 116, 245 / 40R19 101, 245 / 40ZR19 101, 255 / 40R20 104, 255 / 40ZR20 104, 245 / 40R21 103, 245 / 40ZR21 103, 255 / 40R21 105, 255 / 40ZR21 105, 265 / 40R21 108, 265 / 40ZR21 108, 255 / 40R22 106, 255 / 40ZR22 106, 275 / 35R21 105, 275 / 35ZR21 105, 285 / 35R21 108, 285 / 35ZR21 108, 295 / 35R22 111, 295 / 35ZR22 111, 275 / 35R23 108, 275 / 35ZR23 108, 325 / 30R21 111, 325 / 30ZR21 111.

[0061] In some embodiments, the crown reinforcement comprises a working reinforcement including a radially inner working layer and a radially outer working layer positioned radially outside the radially inner working layer.

[0062] In some embodiments, each working layer is axially separated by two axial edges of the working layer and comprises working fibrous reinforcing elements that extend substantially parallel to each other in the axial direction from one axial edge of the working layer to the other axial edge of the working layer.

[0063] Optionally, each working fibrous reinforcing element extends along the circumferential direction of the tire and along the principal direction, which forms an angle in absolute value that is strictly greater than 10°, preferably in the range of 15° to 50°, and more preferably in the range of 20° to 35°.

[0064] Preferably, in an embodiment in which the working reinforcement comprises a radially innermost layer and a radially outermost layer positioned radially outside the radially innermost layer, the main direction in which each working fibrous reinforcing element of the radially innermost working layer extends and the main direction in which each working fibrous reinforcing element of the radially outermost working layer extends form opposite angles with respect to the circumferential direction of the tire.

[0065] Optionally, the crown reinforcement comprises a hoop reinforcement, the hoop reinforcement comprising at least one hooping fibrous reinforcing element that is axially divided by its two axial edges and spirally wound circumferentially between the axial edges so as to extend axially.

[0066] Preferably, the crown reinforcement is positioned radially outward from the working reinforcement.

[0067] Preferably, the hooping fibrous reinforcing element or each of the hooping fibrous reinforcing elements extends along a principal direction that forms an angle with the circumferential direction of the tire of 10° or less in absolute terms, preferably 7° or less, and more preferably 5° or less.

[0068] Further subject matter of the present invention is - Mounting support with rim, - The tire specified above that is mounted on the rim, It is a mounting assembly that includes [a specific feature].

[0069] Advantageously, the crown reinforcement is positioned radially between the tread and the carcass reinforcement and comprises a working reinforcement including at least one axially narrowest working layer, the axially narrowest working layer having an axial width T2 expressed in millimeters, and the rim having a rim width A expressed in millimeters in accordance with the ETRTO standard manual (2019), then the ratio T2 / A is T2 / A ≤ 1.00.

[0070] To control energy dissipation and temperature within the structure during operation of the tire according to the present invention, it is preferable to ensure that the axial width of the narrowest working layer in the axial direction is the correct size relative to the rim width. This is because, under loads exceeding those known from the prior art, the deflection of the tire, i.e., the difference between the radius of the mounting assembly under no load and the radius of the mounting assembly under load, increases considerably. This increase in deflection results in relatively high energy dissipation and a relatively large temperature rise in the tire structure, particularly in the bead.

[0071] To control this, it is preferable to straighten the tire's sidewall, that is, to make the sidewall more radially straight, with the aim of increasing the tire's radial stiffness and avoiding excessive tire deflection, energy dissipation, and temperature rise within the tire's structure. Therefore, -With respect to a given rim width A, the axial width T2 of the narrowest working layer in the axial direction is reduced, thereby reducing the width of the contact patch, and as a result the tire sidewall becomes straight in the radial direction. - With respect to the axial width T2 of the narrowest working layer in the given axial direction, increase the rim width A so that the tire sidewall remains straight in the radial direction. It is recommended to reduce the ratio T2 / A to a value of 1.00 or less.

[0072] If a person skilled in the art changes the axial width T2 of the narrowest working layer in the axial direction, they will adapt the characteristics of the tire crown, in particular the characteristics of the crown reinforcement comprising the working reinforcement and either hoop reinforcement, and the characteristics of the tread according to the axial width T2 they have determined.

[0073] In both cases, the radial stiffness of the tire increases, resulting in a reduction in tire deflection under a given load, thereby at least partially offsetting the effects of the increased load. Consequently, the stress on the tire structure decreases, and therefore energy dissipation and temperature rise during tire operation also decrease.

[0074] To minimize the increase in rotating mass on the vehicle, and to improve vehicle load capacity and compactness by reducing the space occupied by the mounting assembly, it is prioritized to reduce the axial width T2 of the narrowest working layer in the axial direction rather than increasing the rim width A. The axial width of the narrowest working layer in the axial direction is measured in the tire cross-section in the meridional plane and corresponds to the axial width between the two axial ends of the working layer.

[0075] Preferably, the narrowest working layer in the axial direction is the radially outer working layer of the working reinforcement.

[0076] In similarly advantageous embodiments, 0.85 ≤ T2 / A, preferably 0.90 ≤ T2 / A, and more preferably 0.93 ≤ T2 / A ≤ 0.97.

[0077] The ratio T2 / A is preferably not too small. Specifically, it is preferable not to make the axial width T2 of the narrowest working layer in the axial direction excessively small with respect to a given rim width A, because this risks a decrease in bending stiffness along the edge, and consequently, a decrease in cornering stiffness during large turns. Furthermore, if the axial width T2 of the narrowest working layer in the axial direction becomes too small, the width of the contact patch decreases, thereby increasing the pressure applied to the tread and consequently increasing wear. This wear is amplified because the tire according to the present invention is intended to support relatively high loads, inevitably leading to severe wear, more severe than that of the same-sized tire in an EXTRA LOAD version which is required to support small loads in all cases. As explained above, it is also preferable not to make the rim width A too large for the axial width T2 of the narrowest working layer in the axial direction, not only to suppress the increase in rotating mass on the vehicle, but also to reduce the space occupied by the mounting assembly and promote vehicle load capacity and compactness.

[0078] In a preferred embodiment, the tire has a nominal cross-sectional width SW such that T2 ≥ SW-75, preferably T2 ≥ SW-70. With respect to a given nominal cross-sectional width, the axially narrowest working layer, which mainly defines the width of the contact patch, is not too small. Specifically, as described above, this makes it possible to maintain good wear performance of the tire, even though the tire according to the present invention is intended to support relatively high loads that inevitably result in relatively severe wear.

[0079] In a preferred embodiment, the tire has a nominal cross-sectional width SW such that T2 ≤ SW - 27, preferably T2 ≤ SW - 30.

[0080] In these embodiments, as is generally the case with the present invention, the nominal section width is the width indicated by the size marking engraved on the tire sidewall.

[0081] To reduce the risk of mounting a tire on a rim with a width that is too small and results in a relatively high bend at the tire's shoulder, it becomes a priority to limit the rims that can be used with the tire. Therefore, the rims are selected from the following: - The rim width code is equal to the standard measuring rim width code for the tire size, and the rim is defined in accordance with the ETRTO standard manual (2019). - Rims whose rim width code is equal to the standard rim width code for the tire size minus 0.5, and - A rim whose rim width code is equal to the standard rim width code for the tire size plus 0.5.

[0082] The measuring rim is specified in particular on pages 20 to 41 of the section "Passenger car tires - Metric specified tires" in the ETRTO Standards Manual (2019).

[0083] Preferably, in order to suppress the increase in rotating mass on the vehicle and to reduce the space occupied by the mounting assembly, thereby promoting the vehicle's capacity and compactness, the rim has a rim width code equal to the standard rim width code for the tire size minus 0.5.

[0084] Advantageously, tires inflate to a pressure ranging from 200 kPa to 350 kPa, preferably between 250 kPa and 330 kPa. This pressure is the pressure of the mounting assembly at 25°C when the tire is not being driven. This often corresponds to one of the air pressures recommended by the car manufacturer.

[0085] In applications where prioritizing the load-bearing capacity of tires is desired, relatively high pressures of 270 kPa or higher are used.

[0086] In applications where occupant comfort and vehicle behavior, particularly grip on dry ground, are prioritized, relatively low pressures of 270 kPa or less are used.

[0087] A further application of the present invention is a passenger car having at least one tire or mounting assembly as defined above.

[0088] The present invention can be better understood by referring to the drawings and reading the following description, which is given merely as a non-limiting example. [Brief explanation of the drawing]

[0089] [Figure 1] This is a meridional cross-sectional view of a mounting assembly according to the first embodiment of the present invention. [Figure 2] Figure 1 is a meridional cross-sectional view of the tire of the mounting assembly. [Figure 3] Figure 2 is a cross-sectional view taken from line III-III' in plan, showing the carcass reinforcement of the tire in Figure 1. [Figure 4] This figure is similar to Figure 1, comparing the deflection of the mounting assembly of the prior art with the deflection of the mounting assembly in Figure 1. [Modes for carrying out the invention]

[0090] The reference frames X, Y, and Z, corresponding to the normal axial (Y), radial (Z), and circumferential (X) directions of a tire, are shown in the figure.

[0091] The following description uses measurements taken for unloaded, uninflated tires, or for portions of the tire within the meridional plane.

[0092] Figure 1 shows a tire according to the present invention, which is represented as a whole by reference no. 10. The mounting assembly 10 comprises a tire 11 and a mounting support 100 including a rim 200. The tire 11 inflates to a pressure in the range of 200 kPa to 350 kPa, preferably 250 kPa to 330 kPa, in this case equal to 270 kPa.

[0093] The tire 11 has a substantially annular shape around a rotationally symmetric axis R that is substantially parallel to the axial direction Y. The tire 11 is intended for passenger vehicles. In various figures, the tire 11 is depicted as new, i.e., as not yet driven.

[0094] The tire 11 comprises two sidewalls 30 having markings indicating the size of the tire 11, as well as a speed rating and speed code. In this example, the tire 11 has a nominal section width SW in the range of 225 to 315, preferably in the range of 245 to 315, in which case equal to 255. The tire 11 also has a nominal aspect ratio AR in the range of 25 to 55, in this example equal to 40. The tire 11 has a nominal rim diameter in the range of 18 to 23, in this example equal to 21. Thus, the tire 11 has a sidewall height H = 102, defined as SW × AR / 100, which is 95 or greater and 155 or less, preferably 130 or less, more preferably 120 or less, in this example 110 or less.

[0095] According to the present invention, the marking also includes a load index LI in the range of 98 to 116, such that LI ≥ LI'+1 when LI' is the load index of an EXTRA LOAD tire of the same size in accordance with the ETRTO Standard Manual (2019). Preferably, LI'+1 ≤ LI ≤ LI'+4, and even more preferably LI'+2 ≤ LI ≤ LI'+4.

[0096] A tire of size 255 / 40R21 in the EXTRA LOAD version has a load index equal to 102, as shown on page 34 of the "Passenger Car Tyres - Tyres with Metric Designation" section of the ETRTO Standard Manual (2019). Therefore, the load index LI of tire 11 is such that LI ≥ 103, preferably 103 ≤ LI ≤ 106, and even more preferably 104 ≤ LI ≤ 106, in which case LI = 105. This load index equal to 105 corresponds to the load index of a high load capacity tire of size 255 / 40R21 as shown in the ETRTO Manual (2021). Therefore, tire 11 is clearly a high load capacity type.

[0097] For tire 11, the ratio 0.88 ≤ H / LI ≤ 0.98, and in this case, H / LI = 0.97.

[0098] For this size, the ETRTO standard manual (2019), on page 34 of the section "Passenger car tires - metric tires," specifies a measuring rim with a rim width code equal to 9. Therefore, the rim 200 of the mounting assembly 10 is selected from the following: - The rim width code is equal to the standard rim width code for the tire size, and the rim is defined in accordance with the ETRTO standard manual (2019). - Rims whose rim width code is equal to the standard rim width code for the tire size minus 0.5, and - A rim whose rim width code is equal to the standard rim width code for the tire size plus 0.5.

[0099] In this case, the rim 200 of the mounting assembly 10 is a rim whose rim width code is equal to the standard rim width code for the tire size minus 0.5, and therefore equal to 8.5 in this case. The rim 200 has a type J outer shape and rim width A in accordance with the ETRTO standard manual (2019). In this example, since the outer shape of the rim 200 is type 8.5J, its rim width A, expressed in mm, is equal to 215.90 mm.

[0100] Referring to Figure 2, the tire 11 comprises a crown 12, which includes a tread 14 intended to contact the ground during driving, and a crown reinforcement 16 extending circumferentially X within the crown 12. The tire 11 also comprises an airtight layer 18 against expansion gas, which is intended to define an internal cavity with respect to the tire 11 that is closed by the mounting support 100 once the tire 11 is mounted to the mounting support 100.

[0101] The crown reinforcement 16 comprises a working reinforcement 20 and a hoop reinforcement 22. The working reinforcement 16 comprises at least one working layer, in this case two working layers: a radially outer working layer 26 and a radially inner working layer 24 located radially inside it. Of the radially inner layer 24 and the radially outer layer 26, the radially outer layer 26 is the narrowest layer in the axial direction.

[0102] The hoop reinforcement 22 comprises at least one hooping layer, in this case, one hooping layer 28.

[0103] The crown reinforcement 16 has the tread 14 mounted on it in the radial direction. In this case, the hoop reinforcement 22, in this example the hooping layer 28, is positioned radially outside the working reinforcement 20 and is therefore inserted radially between the working reinforcement 20 and the tread 14.

[0104] The two sidewalls 30 extend the crown 12 radially inward. The tire 10 also has two beads 32 radially inward of the sidewalls 30. Each sidewall 30 connects each bead 32 to the crown 12.

[0105] The tire 11 includes a carcass reinforcement 34, which is fixed to each bead 32 and in this case forms a winding around the bead wire 33. The carcass reinforcement 34 extends radially in each sidewall 30 and axially in the crown 12, radially inward of the crown reinforcement 16. The crown reinforcement 16 is positioned radially between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 comprises at least one carcass layer 36, in this case comprising first and second carcass layers 36, 37. The first and second carcass layers 36, 37 extend within each sidewall 30 and radially inward of the crown reinforcement 16 within the crown 12.

[0106] The hoop reinforcement 22, in this example the hooping layer 28, is separated by two axial edges 281 and 282 and comprises one or more hooping fibrous reinforcing elements, which are spirally wound around the circumferential direction between the axial edges 281 and 282 along the main direction which forms an angle AF of 10° or less, preferably 7° or less, and more preferably 5° or less in absolute value, with respect to the circumferential direction X of the tire 10. In this case, AF = -5°.

[0107] Each radially inner working layer 24 and radially outer working layer 26 are axially separated by two axial edges 241, 242, 261, and 262 of each working layer 24 and 26, respectively. The radially inner working layer 24 has an axial width T1 = 224.00 mm, and the radially outer working layer 26 has an axial width T2 = 210.00 mm, making the radially outer working layer 26 the narrowest working layer in the axial direction.

[0108] It should be noted that SW=255 and T2=210.00 satisfy the following relationships: T2≧SW-75, preferably T2≧SW-70, and T2≦SW-27, preferably T2≦SW-30.

[0109] As shown in Figure 1, the mounting assembly 10 is configured such that the tire 11 has a radially straight sidewall. Specifically, the ratio T2 / A is 0.85 ≤ T2 / A ≤ 1.00, preferably 0.90 ≤ T2 / A ≤ 1.00, and more preferably 0.93 ≤ T2 / A ≤ 0.97, in which case T2 / A = 0.97.

[0110] Each working layer 24, 26 is provided with working fibrous reinforcing elements that extend substantially parallel to each other along the principal direction, forming opposite angles AT1 and AT2, respectively, from one axial edge 241, 261 to the other axial edge 242, 262, such that the angles are, in absolute value, greater than 10° in the circumferential direction X of the tire 10, preferably in the range of 15° to 50°, more preferably in the range of 20° to 35°. In this case, AT1 = -26° and AT2 = +26°.

[0111] Each of the first and second carcass layers 36 and 37 has two axial directions end It is divided axially by 361, 362, 371, and 372, and each of them is in one axial direction end The tire 10 is provided with carcass fabric fibrous reinforcing elements 360, 370 extending along the main direction D3, forming an angle AC, from 361, 371 to the other axial edge 362, 372, where the angle is in the range of 80° to 90° in absolute value with respect to the circumferential direction X of the tire 10, in which case AC = +90°.

[0112] The first carcass layer 36 forms a winding around each circumferential reinforcing element 33 of each bead 32 such that the axially inner portions 3611, 3621 of the first carcass layer 36 are positioned inside the axially outer portions 3612, 3622 of the first carcass layer 36 in the axial direction, and the axial ends 361, 362 of the first carcass layer 36 are positioned outside the circumferential reinforcing elements 33 in the radial direction. The axial ends 371, 372 of the second carcass layer 37 are positioned radially inside the axial edges 361, 362 of the first layer, and are positioned axially between the axially inner portions 3611, 3621 and the axially outer portions 3612, 3622 of the first carcass layer 36.

[0113] Each axial end 361, 362 of the first carcass layer 36 is positioned radially inward from the tire's equator E. More specifically, each axial end 361, 362 of the first carcass layer 36 is positioned at a radial distance RNC of 30 mm or less from the radially inward end 331 of each circumferential reinforcing element 33 of each bead 32. In this case, RNC = 23 mm.

[0114] Each working layer 24, 26, hooping layer 28, and carcass layer 36 comprises a calendered base material for the fibrous reinforcing elements of the corresponding layer. Preferably, the calendered base material is a polymer, more preferably an elastomer, as is commonly used in the field of tires.

[0115] Conventionally, each hooping fibrous reinforcement element comprises two multifilament strands, each multifilament strand composed of a spun yarn of aliphatic polyamide, in this case nylon monofilament, with a count of 140 tex. These two multifilament strands are individually twisted spirally at 250 turns per meter, and then twisted together spirally in the opposite direction at 250 turns per meter. These two multifilament strands are then spirally wound around each other. As a variation, a hooping fibrous reinforcement element can be used comprising one multifilament strand composed of aliphatic polyamide, in this case nylon monofilament, with a count of 140 tex, and another multifilament strand composed of aromatic polyamide, in this case aramid monofilament, with a count of 167 tex. These two multifilament strands are individually twisted spirally in one direction at 290 turns per meter, and then twisted spirally in the opposite direction at 290 turns per meter. These two multifilament strands are spirally wound around each other. As an alternative, a hooping fibrous reinforcement element can be used, comprising two multifilament strands, each composed of spun monofilament yarn of aromatic polyamide, in this case aramid, with a count equal to 330 tex, and one multifilament strand, each composed of spun monofilament yarn of aliphatic polyamide, in this case nylon, with a count equal to 188 tex, each of these multifilament strands being individually spirally twisted in one direction at 270 turns per meter, and then spirally twisted in the opposite direction at 270 turns per meter. These two multifilament strands are spirally wound around each other.

[0116] Generally, the use of high loads leads to a decrease in the tire's permissible speed limit and a reduction in its behavior, such as cornering stiffness. Therefore, by using one or more highly elastic hooping fibrous reinforcing elements, such as those described in the last two variations above which include one or more aromatic polyamide strands, it is possible to increase the tire's permissible speed limit and improve its behavior, particularly its cornering stiffness.

[0117] Each working fibrous reinforcing element is an assembly 4.26 of four steel monofilaments, comprising an inner layer of two monofilaments and an outer layer of two monofilaments spirally wound together around the inner layer, for example, in the S direction at a pitch of 14.0 mm. Such an assembly 4.26 has a breaking force equal to 640 N and a diameter equal to 0.7 mm. Each steel monofilament has a diameter equal to 0.26 mm and a mechanical strength equal to 3250 MPa. As a modified form, it is also possible to use an assembly of six steel monofilaments, having a diameter equal to 0.23 mm and comprising an inner layer of two monofilaments spirally wound together around each other in a first direction, for example in the Z direction at a pitch of 12.5 mm, and an outer layer of four monofilaments spirally wound around the inner layer in a second direction opposite to the first direction, for example in the S direction at a pitch of 12.5 mm.

[0118] As shown in Figure 3, each of the first and second carcass layers 36 and 37, each of the carcass fabric fibrous reinforcing elements 360 and 370 comprises an assembly of at least two multifilament strands 363, 364 and 373 and 374. Each multifilament strand 363, 364, 373 and 374 is selected from polyester multifilament strands, aromatic polyamide multifilament strands, and aliphatic polyamide multifilament strands, preferably selected from polyester multifilament strands and aromatic polyamide multifilament. In this example, the assembly is selected from an assembly of two polyester multifilament strands, and an assembly of one polyester multifilament strand and one aromatic polyamide multifilament strand, which in this example consists of two PET multifilament strands, these two multifilament strands are individually spirally twisted in one direction at 420 turns per meter, and then spirally twisted together in the opposite direction at 420 turns per meter. Since each of these multifilament strands has a count equal to 114 tex, the total count of the assembly is 475 tex or less, which in this case is equal to 228 tex.

[0119] Each carcass fabric fibrous reinforcing element 360, 370 has average diameters D1 and D2 such that, when expressed in mm, D1 ≤ 0.90 mm and D2 ≤ 0.90 mm, preferably D1 ≤ 0.85 mm and D2 ≤ 0.85 mm, more preferably D1 ≤ 0.75 mm and D2 ≤ 0.75 mm, and D1 ≥ 0.55 mm and D2 ≥ 0.55 mm, preferably D1 ≥ 0.60 mm and D2 ≥ 0.60 mm. In this case, D1 = D2 = 0.62 mm.

[0120] Official Exam

[0121] To demonstrate the advantages of the present invention, the inventors simulated both the running of the tires and the tension of each fibrous reinforcing element in the carcass of these same tires.

[0122] Driving test simulation

[0123] For each of these tests, a driving simulation similar to the load / speed performance test described in Annex VII of UN / ECE Regulation No. 30 was performed, but under more severe conditions, particularly with greater loads. Various tire sizes, 255 / 40R21, 235 / 60R18, and 255 / 60R18, were simulated as follows: - The tire conforms to the present invention (represented by reference numbers INV1 and INV2), - The tire comprises first and second carcass layers not arranged according to the present invention, wherein each axial end of the second carcass layer is positioned outside the axial outer portions of the first carcass layer in the axial direction (represented by reference numerals COMP1, COMP2, and COMP3).

[0124] During these simulations, the maximum volumetric energy dissipation DNRJ was recorded for a portion of the calendered base material of the first and second carcass layers. This portion is located on the sidewall between the axial directions of the first and second carcass layers and is expressed in units of daN / mm2. A higher value indicates greater energy dissipation due to the tire structure and a greater temperature rise. The results of these simulations are summarized in Table 1 below. [Table 1]

[0125] It should be noted that a specific arrangement of the carcass reinforcement is necessary to reduce energy dissipation, and that an arrangement in which each axial end of the second carcass layer is located outside each axial outer portion of the first carcass layer in the axial direction leads to increased energy dissipation. This is particularly advantageous when the sidewall height H ≤ 130, preferably H ≤ 120, and more preferably H ≤ 110. Specifically, at such sidewall heights, the maximum volumetric energy dissipation DNRJ is relatively high, so the use of the present invention makes it possible to significantly reduce energy dissipation to an acceptable level in absolute terms.

[0126] Even if, in absolute terms, energy dissipation is smaller when the sidewall height exceeds 130 than when it is 130 or less, the present invention still makes it possible to reduce this energy dissipation by approximately 50%.

[0127] Tension simulation

[0128] For each of these tests, the tension of each carcass fibrous reinforcing element was simulated for a tire inflated to a pressure equivalent to 2.8 bar, subjecting it to a load far greater than that used in the load / speed performance tests described in Annex VII of UN / ECE Regulation 30.

[0129] We simulated various tires of the following sizes, 235 / 60R18 and 255 / 60R18, as follows: - The tire has the arrangement of carcass reinforcements according to the present invention (represented by reference numbers INV2 and INV3), - The tire comprises a single carcass layer and therefore does not conform to the present invention (COMP2', COMP3').

[0130] The tension of each carcass fibrous reinforcing element is measured at the edge of the single carcass layer for tires with a single carcass layer, and at the edge of the first carcass layer that forms a winding around the circumferential reinforcing element of each bead for tires with two carcass layers.

[0131] The results of these simulations are summarized in Table 2 below. [Table 2]

[0132] First, it has been shown that in the case of tires having first and second carcass layers, the tension of the carcass fibrous reinforcing elements is significantly reduced compared to tires having a single carcass layer.

[0133] In particular, note that for a given number of carcass layers, the tension increases as the sidewall height increases. Thus, by keeping the sidewall height below 155, the tension of the carcass reinforcement is reduced to a reasonable level.

[0134] Static testing

[0135] To illustrate the effect of straightening the sidewall, which is advantageous but optional within the scope of the present invention, Figure 4 shows the results of a static compression test on a size 255 / 40R21 tire, which is identical to the tire described above, but with a ratio T2 / A equal to 1.04 (tire shown on the left, in this case T1=T2=224mm) and a ratio T2 / A equal to 0.97 (tire shown on the right). The load applied to each tire was equal to 925kg at a pressure of 250kPa.

[0136] Note that the deflection of the left tire is much greater than that of the right tire. Specifically, the distance DR1 from the axis of rotation R to the ground for the left tire is smaller than the distance DR2 from the axis of rotation R to the ground for the right tire.

[0137] In particular, note that the sidewall of the right tire is straighter radially than the sidewall of the left tire. This can be seen by comparing the distances DF1 and DF2 at the same radial point on each sidewall, between the outer surface of the sidewall opposite the contact surface and the plane SA that is perpendicular to the tire's axis of rotation R and passes through the rim's support surface that defines the axial width A of the rim. This can also be seen by comparing the distances DF1' and DF2' between the outer surface of the sidewall and the perpendicular plane SA at the same radial point on each sidewall located parallel to the contact surface. It will be observed that DF1 > DF2 and DF1' > DF2'.

[0138] The present invention is not limited to the embodiments described above.

Claims

1. A passenger car tire (11) comprising a crown (12), two beads (32), two sidewalls (30) connecting each bead (32) to the crown (12), and carcass reinforcements (34) fixed to each bead (32), wherein the crown (12) comprises a crown reinforcement (16) and a tread (14), the carcass reinforcement (34) extends within each of the sidewalls (30) and extends radially inward of the crown reinforcement (16) within the crown (12), and the tire (11) is a high load capacity type in accordance with the ETRTO standard manual (2021). The tire (11) has a sidewall height H defined as H = SW × AR / 100, where SW is the nominal section width of the tire and AR is the nominal aspect ratio of the tire, in accordance with the ETRTO standard manual (2019), and H ≤ H ≤ 155. The carcass reinforcement (34) comprises first and second carcass layers (36, 37), wherein the first carcass layer (36) forms a winding around each circumferential reinforcing element (33) of each bead (32), the axial inner portion (3611, 3621) of the first carcass layer (36) is positioned axially inside the axial outer portion (3612, 3622) of the first carcass layer (36), each of the axial ends (361, 362) of the first carcass layer (36) is positioned radially outside each of the circumferential reinforcing elements (33), and each of the axial ends (371, 372) of the second carcass layer (37) is positioned radially inside each of the axial ends (361, 362) of the first carcass layer (36), further - Between the axial inner portion (3611, 3612) and the axial outer portion (3612, 3622) of the first carcass layer (36) in the axial direction, or - Displaced in the axial direction inside the axial inner portion (3611, 3621) of the first carcass layer (36), Each of the axial ends of the first carcass layer is positioned at a radial distance of 30 mm or less from each of the radially inner ends of each of the circumferential reinforcing elements of the bead. A tire (11) characterized by the following.

2. Each of the axial ends (371, 372) of the second carcass layer (37) is positioned in the axial direction between the axial inner portion (3611, 3621) and the axial outer portion (3612, 3622) of the first carcass layer (36). The tire (11) according to claim 1.

3. H ≤ 130. The tire (11) according to claim 1 or 2.

4. Each of the first and second carcass layers (36, 37) is axially separated by two axial ends (361, 362, 371, 372) of the carcass layer (36, 37) and includes carcass fabric fibrous reinforcing elements (360, 370) that extend axially from one axial end of the carcass layer (36, 37) to the other axial end, along the circumferential direction (X) of the tire (11) and the principal direction, which forms an angle in the range of 80° to 90° in absolute value. A tire (11) according to any one of claims 1 to 3.

5. It has a nominal aspect ratio in the range of 30 to 45, a nominal rim diameter in the range of 18 to 23, and a load index LI in the range of 98 to 116. A tire (11) according to any one of claims 1 to 4.

6. 0.88 ≤ H / LI ≤ 0.98 A tire (11) according to any one of claims 1 to 5.

7. The following sizes and load indices are available: 225 / 55R18 105, 225 / 55ZR18 105, 205 / 55R19 100, 205 / 55ZR19 100, 235 / 45R21 104, 235 / 45ZR21 104, 285 / 45R22 116, 285 / 45ZR22 116, 245 / 40R19 101, 245 / 40ZR19 101, 255 / 40R20 104, 255 / 40ZR20 104, 245 / 40R21 103, 245 / 40ZR21 103, 255 / 40R21 105, 255 / 40ZR21 A size and load index LI selected from among 105, 265 / 40R21, 108, 265 / 40ZR21, 108, 255 / 40R22, 106, 255 / 40ZR22, 106, 275 / 35R21, 105, 275 / 35ZR21, 105, 285 / 35R21, 108, 285 / 35ZR21, 108, 295 / 35R22, 111, 295 / 35ZR22, 111, 275 / 35R23, 108, 275 / 35ZR23, 108, 325 / 30R21, 111, 325 / 30ZR21, 111, has a load index LI. A tire (11) according to any one of claims 1 to 6.

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