Heavy-duty tires with sidewall stiffening inserts

Abstract

The present invention relates to a tire (10) of the HIGH LOAD CAPACITY type, comprising a crown (12), two beads (32) and two sidewalls (30) connecting each bead (32) to the crown (12). The sidewalls (30) are provided with a sidewall insert (90) comprising a so-called hard elastomer composition (92) having a modulus at 10% elongation of at least 6 MPa and a maximum thickness (Emax) of at most 5.0 mm.

Description

[Technical field]

[0001] The present invention relates to a tire. The term "tire" should be understood to mean a tire casing intended to cooperate with a support element, for example a rim, to form a cavity, said cavity being pressurizable to a pressure above atmospheric pressure. The tire according to the invention has a substantially toroidal structure exhibiting rotational symmetry about the main axis of the tire. [Background technology]

[0002] The advent of electric or hybrid passenger cars has led to an increase in vehicle weight, in particular due to the batteries, whose weight is relatively large and substantially proportional to the range (autonomy) of the vehicle. Thus, for example, to increase the range of an electric vehicle, the size of the battery needs to be increased, resulting in an increase in the weight of the vehicle.

[0003] Simply put, it is currently estimated that for every kilometer of range added by an electric propulsion system, the vehicle's weight increases by one kilogram. Therefore, to achieve a range of 500 km, an internal combustion engine vehicle would need to increase in weight by approximately 500 kg. Such vehicles would need to be fitted with tyres that can withstand very high loads.

[0004] Conventionally, a tire for passenger cars capable of withstanding a relatively high load is known. This tire is available commercially as the MICHELIN™ Pilot Sport 4 series and has a size of 255 / 35R18. This tire is offered in an EXTRA-LOAD (abbreviated as XL, representing a tire with extra load-bearing capacity) version within the meaning of the ETRTO Standards Manual 2019, which has a load index equal to 94. This means that at a pressure of 290 kPa, the tire can withstand a load of 670 kg. This load-bearing capacity is relatively high compared to a tire of the same size classified as STANDARD LOAD (abbreviated as SL, representing a tire with standard load-bearing capacity), which has a load index equal to 90 and can withstand a load of 600 kg at a pressure of 250 kPa.

[0005] In order for such tires to be placed on the market, they must pass legal tests: in Europe, for example, tires must pass the load / speed performance tests set out in Annex VII of the Economic Commission for Europe of the United Nations (UN / ECE) Regulation No. 30.

[0006] Nevertheless, in the EXTRA-LOAD version, and even more so in the STANDARD LOAD version, such tires are not able to withstand the additional load corresponding to the batteries required to achieve the desired driving range. Tire manufacturers therefore had to come up with new solutions to meet this new need.

[0007] One solution envisaged by tyre manufacturers is to use a tyre of a larger size for a given vehicle, capable of withstanding a larger load. A given vehicle can therefore be fitted with a tyre having a higher load index. For example, a vehicle fitted with the above-mentioned tyre in an EXTRA-LOAD version can be fitted with a tyre of size 275 / 35R19 in an EXTRA-LOAD version, which has a load index equal to 100 and can withstand a load of 800 kg at a pressure of 290 kPa, much higher than the load of 670 kg.

[0008] On the other hand, such an increase in tire size necessarily results in a reduction in interior space or an increase in the vehicle's outer track width, both of which are undesirable for reasons of vehicle habitability and compactness.

[0009] On the other hand, such an increase in tire size would require a new vehicle chassis design, which is also undesirable for obvious cost reasons.

[0010] Finally, such an increase in tire size, and in particular an increase in nominal section width, leads to an increase in external noise generated by the tire and to an increase in rolling resistance, both of which are undesirable if one wishes to reduce noise pollution and vehicle energy consumption.

[0011] Therefore, another solution envisaged by tire manufacturers is to recommend higher air pressures for a given size and version of tire: the higher the air pressure, the higher the tire can withstand a higher load.

[0012] However, using a relatively high recommended inflation pressure increases tire stiffness and reduces comfort for vehicle occupants, which is obviously undesirable for certain vehicle manufacturers where occupant comfort takes priority over load carrying capacity.

[0013] Thus, tire manufacturers decide to create a new type of tire, now known by the name "HIGH LOAD CAPACITY" (or high load) in the ETRTO Standards Manual 2021. This new type of tire ensures that a tire of a given size can withstand a load greater than that of a tire of the same size but in its EXTRA-LOAD version. Thus, for a size of 255 / 35R18, a tire of type HIGH LOAD CAPACITY has a load index equal to 98, indicating that it can withstand a load of 750 kg at a pressure of 290 kPa.

[0014] One of the problems faced has to do with the fact that, for the same size, a HIGH LOAD CAPACITY type tire must withstand a relatively high load, which leads to a deterioration in the vehicle's maneuverability, especially when the vehicle is yawed. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] International Publication No. 2021 / 123522 [Patent Document 2] International Publication No. 2014 / 184158 [Patent Document 3] International Publication No. 2018 / 111773 Summary of the Invention [Problem to be solved by the invention]

[0016] SUMMARY OF THE PRESENT EMBODIMENT It is therefore an object of the present invention to provide a vehicle equipped with HIGH LOAD CAPACITY type tires with sufficient maneuverability. [Means for solving the problem]

[0017] The invention therefore relates to a tyre for passenger vehicles comprising a crown, two beads and two sidewalls connecting each bead to the crown, the tyre being of the HIGH LOAD CAPACITY type in accordance with the ETRTO Standards Manual 2021, the tyre comprising a sidewall insert 90 arranged axially between the outer face of at least one of the sidewalls and the inner face of the sidewall, each sidewall insert 90 comprising at least one elastomeric composition, termed hard, the or each hard elastomeric composition of the sidewall insert having a modulus of elasticity at 10% elongation equal to or greater than 6 MPa, and the maximum thickness of the hard elastomeric composition or of the assembly of hard elastomeric compositions equal to or less than 5.0 mm.

[0018] In order to carry out the invention, the inventors had to understand why the handling characteristics obtained were not satisfactory. After many tests, the inventors discovered that the sidewall of the tire forms a flexible portion lying between two rigid portions formed at one end by the crown reinforcement and at the other end by each of the beads.

[0019] Thus, when a tire is subjected to high forces, and in particular when the tire is subjected to high loads, the stiff parts formed by the crown reinforcement and the beads transmit a relatively high proportion of these forces to the parts of the tire that are least hard or stiff, in this case the sidewalls, which, being located radially between the beads and the crown, now deflect with relatively large deflection amplitudes, and therefore the handling performance is impaired.

[0020] Once the reasons for maneuverability were understood, the inventors behind the present invention also needed to find a technical solution to make a vehicle equipped with HIGH LOAD CAPACITY type tires maneuverable well.

[0021] Thus, the inventors have discovered that by using a relatively stiff sidewall insert (in any case stiffer than the stiffness of the elastomeric composition normally present in the sidewall of a tire), the deflection amplitude of each sidewall can be reduced, thereby improving vehicle handling.

[0022] Furthermore, the use of the sidewall insert according to the invention, unlike other solutions such as, for example, the use of reinforced carcass reinforcements, presents the advantage of offering a better compromise between its manufacturing costs and its effect on handling: in particular, since the sidewall insert at least partially replaces the material already present in the sidewall of the tire, the manufacturing costs of a tire according to the invention are not significantly increased compared to a tire without the sidewall insert.

[0023] With regard to the modulus at 10% elongation, commonly referred to as MA10, this is the modulus of elasticity of the mixture measured during a uniaxial tensile test at an elongation value of 0.1 (i.e. 10% elongation expressed as a percentage). The specimen is subjected to a uniaxial tension at a constant rate and the elongation and force are measured. The measurements are carried out with an INSTRON® type tensile tester at a temperature of 23° C. and a relative humidity of 50% (as per the ISO 23529 standard). The conditions for carrying out the measurements and using their results to determine the elongation and stress are as described in the NF ISO 37:2012-03 standard. The stress is determined for an elongation of 0.1 and the tensile modulus at 10% elongation is calculated as the ratio between this stress value and the elongation value. A person skilled in the art knows how to select and adapt the dimensions of the specimens depending on the amount of the mixture available and available, especially when taking specimens from tires.

[0024] The elastomeric composition of the sidewall insert is based on one or more elastomers and may contain fillers and other ingredients routinely used in the field of tire compositions.

[0025] The tire according to the invention is not suitable for run-flat. A tire suitable for run-flat is suitable for running when the pressure in the internal cavity of the tire is equal to atmospheric pressure (often, due to the use of improper language, the pressure is said to be zero, which is an overpressure relative to atmospheric pressure). A tire suitable for run-flat has a self-supporting sidewall, i.e. a sidewall that is capable of withstanding the same load as the tire can withstand when inflated to a normal pressure, e.g. the nominal pressure as indicated in the European Tire and Rim Technical Organisation (ETRTO) Standards Manual 2021, over a distance of a certain threshold at a speed of 80 km / h or more, in the presence of a pressure equal to atmospheric pressure. A tire suitable for run-flat preferably has a specific marking indicating the tire's ability to run flat. Thus, for example, the following markings in the form of acronyms are used, although this list is not exhaustive: "ZP" for "Zero Pressure", "SST" for "Self Supporting Technology", "SSR" for "Self Supporting Runflat Tyre", "RF" for "Run Flat", "RFT" for "Run Flat Tyre", "EXT" for "Extended", "ZP-SR" for "Zero Pressure Short Range" or even "ZPS" for "Zero Pressure System". Another specific indication of the tire's ability to run flat is the inclusion of the letter "F" in the tire size number. Thus, a tire of the dimensions 225 / 40R18 or 225 / 40ZR18, if suitable for runflat, is marked 225 / 40RF18 or 225 / 40ZRF18.

[0026] According to the invention, the tire is a tire for passenger cars. Such tires are, for example, specified in the ETRTO (European Tire and Rim Technical Organisation) Standards Manual 2021. Such tires generally have, on at least one of the sidewalls, a marking indicating the size of the tire in accordance with the markings of the ETRTO Standards Manual 2021 in the form of X / YαVUβ, where X designates the nominal section width, Y designates the nominal aspect ratio, α designates the structure and may be R or ZR, V designates the nominal rim diameter, U designates the load index, and β designates the speed symbol.

[0027] By increasing the load index of the tire compared to the load index of a tire of the same size in an EXTRA-LOAD version, the present invention can increase the load-bearing performance of the tire without resulting in changes in the habitability, compactness and comfort of the vehicle using the tire. In particular, since the size of the tire of the present invention is the same as that of the tire of the EXTRA-LOAD version, the tire does not take up more space than the tire of the EXTRA-LOAD version. The tire of the present invention can have a distinctive marking, such as, for example, the marking HL (HIGH LOAD) or XL+ (EXTRA LOAD+), so that it can be distinguished from its STANDARD LOAD and EXTRA-LOAD versions. Such markings are specifically disclosed in the ETRTO Standards Manual 2021, on page 3 in the section entitled "General Notes - Tires for Passenger Cars", for designating tires of the HIGH LOAD CAPACITY type. Also, examples of sizes are disclosed in the ETRTO Standards Manual 2021, on page 44, in the section entitled "Tires for Passenger Cars - Tires by Metric Designation", in paragraph 9.1.

[0028] A tire of the HIGH LOAD CAPACITY type 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 Standards Manual 2021. The load index LI' is the load index of an EXTRA-LOAD tire of the same size, i.e. of 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 Standards Manual 2021, in particular in the part entitled "Passenger Car Tires - Tires with Metric Designations", pages 22 to 43. Depending on the size, LI=LI'+1, or LI=LI'+2, or LI=LI'+3, or LI=LI'+4. In most embodiments, LI'+1≦LI≦LI'+4, or even LI'+2≦LI≦LI'+4.

[0029] The maximum thickness of the hard elastomer composition or the hard elastomer composition aggregate is the maximum value of the thickness of the hard elastomer composition or the hard elastomer composition aggregate, which thickness can be constant or variable. The thickness of the hard elastomer composition or the hard elastomer composition aggregate is defined as the thickness of the hard elastomer composition or the hard elastomer composition aggregate at a point on the inner surface of the tire in a meridian section. The thickness of the hard elastomer composition or the hard elastomer composition aggregate at this point on the inner surface is the linear distance between the radially innermost point of the hard elastomer composition or the hard elastomer composition aggregate and the radially outermost point of the hard elastomer composition or the hard elastomer composition aggregate along the normal to the inner surface at this point on the inner surface, these points on the sidewall insert being aligned along the normal to this point on the inner surface.

[0030] The inner surface defines the tire's internal cavity, which is intended to be pressurized with inflation gas once the tire is mounted on a mounting support, such as a rim. The inner surface of the sidewall is thus that portion of the sidewall which defines the tire's internal cavity.

[0031] The outer surface is the surface of the tire that is in contact with air at atmospheric pressure and is visible from the outside of the tire. Thus, the outer surface of the sidewall is that part of the sidewall that is in contact with air at atmospheric pressure and is visible from the outside of the tire.

[0032] In a preferred embodiment, the or each sidewall insert comprises a hard elastomeric composition. In a particular variant, the or each sidewall insert is made of a hard elastomeric composition. In another variant, the or each sidewall insert comprises a hard elastomeric composition and one or more elastomeric compositions, called flexible, whose modulus at 10% elongation is strictly less than 6 MPa. In these embodiments, the maximum thickness is the thickness of the hard elastomeric composition.

[0033] However, in other embodiments, it is also conceivable that the or each sidewall insert comprises a plurality of hard elastomeric compositions. In these embodiments, the maximum thickness is the maximum value with respect to the maximum thickness of the collection of hard elastomeric compositions, i.e. the sum of the thicknesses of each hard elastomeric composition measured along the same normal to the inner surface of the tire. In certain variants of these embodiments comprising a plurality of hard elastomeric compositions, all of the elastomeric compositions of the sidewall insert are hard elastomeric compositions. In other variants of these embodiments comprising a plurality of hard elastomeric compositions, the sidewall insert comprises, in addition to the hard elastomeric compositions, one or more elastomeric compositions, called flexible, whose modulus at 10% elongation is strictly less than 6 MPa. In these other variants, the maximum thickness does not take into account the thickness of the or each flexible elastomeric composition, and the maximum thickness is defined as the maximum thickness of the collection of hard elastomeric compositions.

[0034] The tire according to the invention has a substantially toroidal shape about an axis of rotational symmetry substantially coinciding with the axis of rotation of the tire, which axis of rotational symmetry defines the three directions conventionally used by those skilled in the art: axial, circumferential and radial.

[0035] The expression "axially" means the axis of rotational symmetry of the tire, i.e. the direction substantially parallel to the axis of rotation of the tire.

[0036] The expression "circumferential" means a direction substantially perpendicular to both the axial direction and the radius of the tire (in other words, tangent to a circle about the axis of rotation of the tire).

[0037] The term "radial" means any direction along the radius of the tire, i.e., any direction intersecting the axis of rotation of the tire and substantially perpendicular to that axis.

[0038] The expression "median plane of the tire (denoted M)" means a plane perpendicular to the axis of rotation of the tire, located axially midway between the two beads and passing through the axial center of the crown reinforcement.

[0039] The expression "equatorial circumferential plane of the tire" means the combination of a plane passing through the tire's equator (designated E) in each meridian section and perpendicular to the median plane and to the radial direction. The equator of the tire is the axis, in a meridian section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions), parallel to the tire's axis of rotation and equidistant between the radially outermost point of the tread intended to come into contact with the ground and the radially innermost point of the tire intended to come into contact with a support, for example the rim, the distance between these two points being equal to H.

[0040] The expression "meridian plane" means a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0041] The expressions "radially inward / inside of" and "radially outward / outside of" mean "closer to the tire's axis of rotation than" and "further from the tire's axis of rotation than", respectively. The expressions "axially inward / inside of" and "axially outward / outside of" mean "closer to the tire's median plane than" and "further from the tire's median plane than", respectively.

[0042] "Bead" means the part of the tire intended to enable the tire to be fixed to a mounting support, for example a wheel with a rim. Each bead is therefore intended in particular to be in contact with the flange of the rim enabling the tire to be mounted. The radially outer edge of the outer bead surface of a tire is therefore defined as the radially outermost point of the outer surface of the tire that is in contact with a reference rim when the tire is inflated to its rated pressure on the reference rim in accordance with the ETRTO Standards Manual 2021.

[0043] A range of values ​​expressed by the expression "between a and b" denotes a range of values ​​extending from greater than a to less than b (i.e. excluding the endpoints a and b), whereas a range of values ​​expressed by the expression "from a to b" means a range of values ​​extending from a to b (i.e. including the precise endpoints a and b).

[0044] In a particular preferred embodiment of the invention, the tire is intended for passenger vehicles as defined in the ETRTO Standards Manual 2021. Such a tire has a cross section in a meridian section characterized by a section height H and a nominal section width S as defined in the ETRTO Standards Manual 2021, optionally such that the ratio H / S, expressed as a percentage, is at most equal to 90, preferably at most equal to 50, more preferably at most equal to 40, at least equal to 20, preferably at least equal to 25, and the nominal section width S is at least equal to 155 mm, preferably at least equal to 205 mm, more preferably at least equal to 225 mm, at most equal to 385 mm, preferably at most equal to 335 mm. Furthermore, the rim flange diameter D, which defines the diameter of the rim for mounting the tire, is at least equal to 12 inches, preferably at least equal to 16 inches and at most equal to 24 inches.

[0045] In one optional embodiment, each sidewall comprises a sidewall insert axially disposed between an outer surface of the sidewall and an inner surface of the sidewall, each sidewall insert comprising at least one elastomeric composition referred to as hard, the or each hard elastomeric composition of each sidewall insert having a modulus of elasticity at 10% elongation of 6 MPa or greater, and the maximum thickness of the hard elastomeric composition or assembly of hard elastomeric compositions being 5.0 mm or less.

[0046] Thus, in a first variant, two sidewall inserts may be arranged in the two sidewalls of the tire, these two sidewall inserts having the same maximum thickness and the same hard elastomer composition(s).

[0047] In a second variant, two sidewall inserts can be arranged on the two sidewalls of the tire, these two sidewall inserts having one or more hard elastomer compositions with different maximum thicknesses and / or different moduli at 10% elongation. In particular, when the tire has a mounting direction pointing to the outside and to the inside when it is mounted on the vehicle, preference is given to the scenario in which the insert of the sidewall intended for the outside has one or more hard elastomer compositions with a maximum thickness and / or moduli at 10% elongation greater than the insert of the sidewall intended for the inside.

[0048] In an advantageous embodiment, the or each hard elastomeric composition has a modulus at 10% elongation of not more than 20 MPa, preferably not more than 15 MPa, more preferentially not more than 13 MPa. This improves the handling of the vehicle, but excessive stiffness may still reduce the comfort of the vehicle. Moreover, excessive stiffness may impair flattening and reduce the surface area of ​​the ground contact patch. It is therefore preferable to use a sidewall insert that is not too stiff.

[0049] In an advantageous embodiment, the maximum thickness of the hard elastomer composition or of the mass of hard elastomer compositions is in the range of 1.0 mm to 5.0 mm, preferably 1.0 mm to 3.5 mm, more preferably 1.0 mm to 2.5 mm, and even more preferably 1.2 mm to 1.7 mm. This stiffness is considerably greater than that of compositions conventionally used in tire sidewalls, but the greater the maximum thickness, the greater the improvement in vehicle handling. However, exceeding a maximum thickness that is too great reduces the comfort of the vehicle, as well as flattening, which leads to a reduction in the surface area of ​​the contact patch.

[0050] In another advantageous embodiment, if the or each sidewall has a minimum thickness at point I, the thickness of the sidewall at a point on the inner surface is defined as the linear distance between this point on the inner surface and a point on the outer surface of the tire aligned with this point on the inner surface along the normal to the inner surface at this point on the inner surface, and the point on the inner surface at which the thickness of the hard elastomeric composition or of the aggregate of hard elastomeric compositions is maximum is defined as: - a radially outer straight line formed by a normal to the inner surface passing through a point on the inner surface located 10 mm radially outside point I; - a radially outer straight line formed by a normal to the inner surface passing through a point on the inner surface located 10 mm radially outside point I; The electrodes are arranged radially between the electrodes.

[0051] In other words, the thickness of the hard elastomeric composition or mass of hard elastomeric compositions is greatest near the area where the sidewall has a minimum thickness. In fact, for the same stiffness or hardness, the sidewall will deflect the most at the point where its thickness is at a minimum. Therefore, in order to effectively improve the vehicle's handling, it is advantageous to stiffen the sidewall in this area that may experience a high degree of deflection.

[0052] Optionally, the thickness of the hard elastomeric composition or mass of hard elastomeric compositions is greatest radially outward of the equator of the tire.

[0053] In an advantageous embodiment, the radially outer end of the sidewall insert is located radially outward of the equator of the tire.

[0054] Advantageously, optionally, the radially outer end of the sidewall insert is disposed radially and axially inward of a line perpendicular to the inner surface and passing through the axially outer end of the axially widest crown layer of the crown reinforcement.

[0055] In fact, the sidewall insert would unnecessarily increase the weight and rolling resistance of the tire by extending beyond the axially outer end of the axially widest crown layer.

[0056] In some embodiments, the radially outer end is the radially outer end of the hard elastomeric composition or the radially outer end of the hard elastomeric composition of the mass, while in other embodiments, the radially outer end is the radially outermost end of the hard elastomeric composition or the flexible elastomeric composition of the insert.

[0057] In another advantageous embodiment, the radially inner end of the sidewall insert is located radially inward of the equator of the tire.

[0058] Advantageously, and optionally, the radially inner end of the sidewall insert is disposed radially and axially outboard of a line perpendicular to the inner surface and passing through the radially outer end of the outer surface of the bead of the tire.

[0059] In fact, the sidewall insert does not need to extend too far radially inward, especially into the bead, because, as pointed out in the introduction, this area of ​​the tire is already sufficiently stiff, which would result in the tire being unnecessarily heavy.

[0060] In some embodiments, the radially inner end is the radially inner end of the hard elastomeric composition or the radially inner end of the hard elastomeric composition of the mass, while in other embodiments, the radially inner end is the radially innermost end of the hard elastomeric composition or the flexible elastomeric composition of the insert.

[0061] Optionally but advantageously, the or each sidewall insert has a generally crescent-shaped cross-section such that the cross-sectional width of the sidewall insert is smallest at its radially inner and outer ends and greatest therebetween.

[0062] Optionally, the tire comprises a carcass reinforcement including at least one carcass layer anchored to the or each bead and extending radially within the or each sidewall and axially within the crown radially inward of the crown reinforcement.

[0063] Optionally, the or each carcass layer is axially bounded by two axial ends and optionally and preferably comprises carcass reinforcing elements extending axially from one axial end to the other axial end of the carcass layer in a main direction which forms an angle, expressed in absolute value, with the circumferential direction of the tire of at least 60°, preferably in the range 80° to 90°.

[0064] In a particular embodiment, the tire includes an inner liner layer supporting an inner surface thereof, the sidewall insert being axially disposed between the inner liner layer and the axially innermost carcass layer.

[0065] In other embodiments, it is envisioned that the sidewall insert is disposed axially between the axially outermost carcass layer and the outer surface of the tire.

[0066] In particular variants, the carcass reinforcement comprises a single carcass layer anchored to the or each bead and extending radially in the respective sidewall and axially in the crown radially inside the crown reinforcement. In these variants, the invention makes it possible in particular to avoid the addition of a second carcass layer, or indeed the use of reinforced carcass reinforcing elements, in order to improve the vehicle's handling. The expression "single carcass layer anchored to the or each bead" means that the carcass reinforcement is not provided with any layer reinforced with reinforcing elements anchored to the or each bead, apart from this carcass layer. Reinforcing elements of such a reinforcing layer excluded from the carcass reinforcement of the tire include metal reinforcing elements and textile reinforcing elements. Very preferably, the carcass reinforcement is made up of a single carcass layer. Even more preferably, the tire does not have a sidewall reinforcing layer as defined below.

[0067] In a first configuration of the carcass reinforcement comprising a single carcass layer, the carcass layer anchored to each bead is wrapped around the circumferential reinforcing elements of each bead such that its axially inner portion is positioned axially inside its axially outer portion.

[0068] In a second configuration of the carcass reinforcement comprising a single carcass layer, each bead comprises an axially inner circumferential reinforcing element arranged axially inside the carcass layer and an axially outer circumferential reinforcing element arranged axially outside the carcass layer, as described, for example, in WO 2021 / 123522.

[0069] In another variant, the carcass reinforcement comprises a first and a second carcass layer anchored to the or each bead and extending radially in each sidewall and axially in the crown radially inside the crown reinforcement, the sidewall insert being arranged axially inside the first carcass layer. In these other variants, the invention makes it possible in particular to avoid the use of a sidewall reinforcing layer to improve the handling of the vehicle or the use of reinforced carcass reinforcing elements. At the same time, the presence of two carcass layers in the crown of the tire results in improved performance of the tire in the regulatory "breaking energy test".

[0070] As mentioned above, it is envisaged that the sidewall insert is located axially inward of the axially innermost carcass ply. It is also envisaged that the sidewall insert is located axially between the first and second carcass plies.

[0071] In a first configuration of a carcass reinforcement comprising first and second carcass layers, the first carcass layer is wrapped around the circumferential reinforcing element of each bead such that its axially inner portion is positioned axially inside its axially outer portion and each of its axial ends is positioned radially outside each of the circumferential reinforcing elements, and each of the axial ends of the second carcass layer is positioned radially inside each of the axial ends of the first carcass layer.

[0072] In a first variation of the first configuration, each axial end of the second carcass layer is axially disposed between the axially inner and outer portions of the first carcass layer, and in this variation, the second carcass layer is disposed radially outward of the first carcass layer at the crown.

[0073] In a second variation of the first configuration, each axial end of the second carcass layer is disposed axially inward of an axially inner portion of the first carcass layer, and in this variation, the second carcass layer is disposed radially inward of the first carcass layer at the crown and axially inward of the first carcass layer at each sidewall.

[0074] Such an arrangement of the first and second carcass layers in the first and second variants makes it possible to obtain an effective mechanical bond between the first and second carcass layers and to reduce the shear effects between the first and second carcass layers, which then reduces the energy dissipation and the increase in tire temperature, taking into account that the shear effects are particularly significant, especially at high loads.

[0075] Moreover, thanks to the special arrangement of the first and second carcass layers, a tire is obtained that, surprisingly, exhibits an optimal energy dissipation in the sidewall and an optimal operating temperature, especially under high loads and at pressures below the recommended pressure for tires of the same size in the standard load or extra load versions. This is all the more surprising considering that the specific arrangement of the first and second carcass layers in one area of ​​the tire, in this case in or near the bead, allows a reduction in the energy dissipation in another area of ​​the tire remote from the bead, in this case the sidewall. It has been found that the specific arrangement of the carcass reinforcement, i.e. the axial ends of the second carcass layer are arranged axially between the axially inner and axially outer parts of the first carcass layer or axially inside the axially inner part of the first carcass layer, allows a reduction in the difference in tension between the first and second carcass layers. However, the smaller the tension difference between the first and second carcass layers, the smaller the shear action occurring between the first and second carcass layers and the less energy dissipation.

[0076] In a third variation of the first configuration, the axial ends of the second carcass layer are disposed axially outward of the axially outer portions of the first carcass layer, and the second carcass layer is disposed radially outward of the first carcass layer at the crown and axially outward of the first carcass layer at each sidewall.

[0077] This third variant is particularly advantageous for tires with relatively high sidewalls. In particular, for tires of the HIGH LOAD CAPACITY type with relatively high sidewalls, due to the high tensions at the ends of the first carcass layer, it is preferable to envisage carcass reinforcements arranged axially outside the respective axially outer portions of the first carcass layer, different from the arrangements described in the first and second configurations. Such an arrangement of the carcass reinforcements reduces the tensions at the ends of the first carcass layer to a lower level.

[0078] In a second configuration of the carcass reinforcement comprising first and second carcass layers, where each bead comprises at least a first and a second circumferential reinforcing element, a portion of each of the first and second carcass layers is arranged axially between at least two of the first and second circumferential reinforcing elements. Such a configuration is described in particular in WO 2021 / 123522.

[0079] Regardless of the number of carcass layers in each first configuration, in a particular variant, each axial end of the carcass layer or of the first carcass layer is positioned radially inside the equator of the tire and, even more preferentially, at a radial distance of not more than 30 mm from the radially inner end of each circumferential reinforcing element of each bead.

[0080] By locating the axial ends of the wound carcass layers inside the equator of the tire, the mass of the carcass reinforcement is significantly reduced. Moreover, the majority of rims currently used for passenger car tires have J-shaped flanges that are in all cases less than 30 mm high. The highly preferential location of the axial ends in a region that corresponds substantially radially to the flange of the rim makes it possible to mechanically protect them. In particular, if the axial ends are located too high radially above the circumferential reinforcing elements of the beads, i.e. at a radial distance strictly more than 30 mm from the radially inner end of the circumferential reinforcing elements, they will be located in flexible regions of the tire that are subject to excessive stresses, which are excessively high for tires of the HIGH LOAD CAPACITY type.

[0081] Regardless of the number of carcass layers in each first configuration, in other variants, the axial end of the carcass layer or the first carcass layer is arranged radially outside the equator of the tire. Advantageously, in these alternative embodiments, the axial end of the carcass layer or the first carcass layer is arranged with a great preference axially inside the axial end of at least one of the crown layers or crown layers of the crown reinforcement.

[0082] In yet another variant, the carcass reinforcement comprises a single carcass ply anchored to each bead and extending radially in each sidewall and axially in the crown radially inward of the crown reinforcement, the tire comprising at least one carcass ply extending radially in each sidewall and having: a radially inner end located radially inside the equator of the tire; a radially outer end located radially outside the equator of the tire; The sidewall reinforcing layer has

[0083] In these further variants, the invention makes it possible in particular to dispense with the use of a second carcass layer extending axially within the crown, radially inside the crown reinforcement, so that the sidewall reinforcing layer is discontinuous under the crown of the tire.

[0084] The sidewall reinforcing layer is not anchored to the bead of the tire, and therefore the radially inner end of the sidewall reinforcing layer is disposed radially outward of the bead.

[0085] In some advantageous embodiments, the crown reinforcement comprises a working reinforcement including at least one working layer and one hoop reinforcement including at least one hoop layer, the hoop reinforcement being positioned radially outward of the working reinforcement.

[0086] Optionally, the or each hoop layer is axially bounded by two axial ends, the or each hoop layer comprising one or more hoop reinforcing elements spirally wound in the circumferential direction so as to extend axially in a main direction from one axial end of the hoop layer to the other axial end of the hoop layer, optionally and preferably this main direction forms an angle with the circumferential direction of the tire that is equal to or smaller than 10°, preferably equal to or smaller than 7° and more preferentially equal to or smaller than 5° in absolute value.

[0087] Optionally, the or each working layer is axially delimited by two axial ends, the or each working layer comprising working reinforcing elements extending axially from one axial end to the other axial end, substantially parallel to one another in a main direction which forms an angle with the circumferential direction of the tire strictly greater than 10° in absolute value, preferably lying in the range from 15° to 50°, more preferentially in the range from 25° to 45°.

[0088] Suitably the or each hoop, working and carcass reinforcing element is a thread-like reinforcing element.

[0089] The term "reinforcing element" means an element that provides mechanical reinforcement to the polymer matrix in which it is intended to be embedded.

[0090] Preferably, each reinforcing element is thread-like, i.e. each reinforcing element has a length at least 10 times greater than the largest dimension of its cross-section, regardless of whether the cross-sectional shape is circular, elliptical, oval, polygonal, in particular rectangular or square or oval. In the case of a rectangular cross-section, the thread-like reinforcing elements are strip-like.

[0091] In an optional but advantageous embodiment, the tire has a sidewall height H defined as H=SW×AR / 100, where SW is the nominal section width and AR is the nominal aspect ratio of the tire, and the load index LI satisfies H / LI≧0.85, preferably H / LI≧0.90, where SW, AR and LI are defined in accordance with the ETRTO Standards Manual 2021. The invention is therefore preferentially applicable to tires whose maneuverability is easily impaired due to the sidewall height. In particular, the higher the sidewall, the more likely it is to deflect relatively more, especially if its load index is high. The invention allows for a satisfactory maneuverability to be obtained for these tires.

[0092] The nominal section width SW and the nominal aspect ratio AR are from a size marking imprinted on the sidewall of the tire, e.g., in accordance with the ETRTO Standards Manual 2021.

[0093] The invention will be better understood on reading the following description, given purely by way of non-limiting example and in conjunction with the drawings, in which: [Brief description of the drawings]

[0094] [Figure 1] 1 is a meridian section, parallel to the axis of rotation of a tire, of a tire according to a first embodiment of the invention; FIG. [Diagram 2] FIG. 2 is a detailed view of one of the sidewalls of the tire of FIG. 1. [Diagram 3] FIG. 2 is a view similar to FIG. 1 for a tire according to a second embodiment of the invention. [Figure 4] FIG. 2 is a view similar to FIG. 1 for a tire according to a third embodiment of the invention. [Diagram 5]FIG. 2 is a view similar to FIG. 1 for a tire according to a fourth embodiment of the invention. [Figure 6] FIG. 2 is a view similar to FIG. 1 for a tire according to a fifth embodiment of the invention. [Figure 7] FIG. 2 is a view similar to FIG. 1 for a tire according to a sixth embodiment of the invention. [Figure 8] 2 is a graph showing cornering stiffness for the tire of FIG. 1 and a control tire not according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0095] Reference systems X, Y, Z, which correspond respectively to the normal axial (Y), radial (Z) and circumferential (X) directions of the tire, are shown in the diagram for the tire.

[0096] FIG. 1 shows a tire according to the invention, designated by the general reference number 10. The tire 10 has a substantially toroidal shape around an axis of rotation substantially parallel to an axial direction Y. The tire 10 is intended for passenger cars and has the dimensions 305 / 35R23. In the various figures, the tire 10 is shown as new, i.e. before it has been driven. The tire 10 has a sidewall height H defined by H=SW×AR / 100, where FW is the nominal section width, in this case 305, AR is the nominal aspect ratio of the tire, in this case 35, and the load index LI is in this case equal to 114. The load index therefore satisfies H / LI≧0.85, preferably H / LI≧0.90, in this case H / LI=0.94. SW, AR and LI are defined in accordance with the ETRTO Standards Manual 2021.

[0097] The tire 10 comprises a crown 12 with a tread 14 intended to come into contact with the ground during running, and a crown reinforcement 16 extending within the crown 12 in a circumferential direction X. The tire 10 also comprises an airtight inner liner layer 18 that is impermeable to inflation gas and that, once the tire 10 is mounted on a mounting support, for example a rim, is intended to delimit, together with the mounting support of the tire 10, an internal cavity that is intended to be pressurized with inflation gas. This inner liner layer 18 bears against an inner surface 19 of the tire 10. The tire 10 also has an outer surface 31.

[0098] The crown reinforcement 16 comprises a working reinforcement 20 and a hoop reinforcement 22, each of which comprises at least one crown layer. The working reinforcement 20 comprises at least one working layer, here two working layers, a radially outer working layer 26 and a radially inner working layer 24 disposed radially inwardly thereof.

[0099] The hoop reinforcement 22 comprises at least one hoop layer, in this case one hoop layer 28 .

[0100] The crown reinforcement 16 is arranged radially inside the tread 14. In this case, the hoop reinforcement 22, in this case the hoop layer 28, is arranged radially outside the working reinforcement 20 and is thus interposed radially between the working reinforcement 20 and the tread 14.

[0101] The tire 10 comprises two sidewalls 30 extending radially inwardly from the crown 12. The tire 10 further comprises two beads 32 radially inwardly of the sidewalls 30. Each sidewall 30 connects each bead 32 to the crown 12. Each sidewall 30 bears on a portion of its outer surface 31.

[0102] The tire 10 includes a carcass reinforcement 34. The crown reinforcement 16 is disposed radially between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 includes at least one carcass layer 36, in this case a single carcass layer 36 anchored to each bead 32. The carcass layer 36 extends radially at each sidewall 30, axially at the crown 12, and radially inward of the crown reinforcement 16.

[0103] For anchoring the carcass layer 36, the tire 10 comprises an axially inner circumferential reinforcing element 38 arranged axially inside the carcass layer 36 and an axially outer circumferential reinforcing element 40 arranged axially outside the carcass layer 36. Here, each reinforcing element 38, 40 comprises a continuous thread-like reinforcing element wound multiple times in the circumferential direction, as described, for example, in WO 2021 / 123522.

[0104] The crown reinforcement 16 comprises two axial ends 161 , 162 which here coincide with the ends of the axially widest layer of the crown reinforcement 16 .

[0105] Each working layer 24, 26, hoop layer 28 and carcass layer 36 comprises a polymer matrix, in this case an elastomeric matrix, in which one or more reinforcing elements of the corresponding layer are embedded, in this case thread-like reinforcing elements. This matrix is ​​said to be polymeric because it is based on a polymer composition, which may for example be one or more polymers chosen from thermoplastic polymers, thermoset polymers, elastomers, thermoplastic elastomers, but also fillers and other ingredients routinely used in the field of tire compositions, in particular compositions for embedding reinforcing elements.

[0106] The hoop reinforcement 22, in this case the hoop layer 28, is axially delimited by two axial ends, in this case axial ends 161, 162. The hoop reinforcement 22 comprises one or more filamentary hoop reinforcing elements spirally wound in the circumferential direction so as to extend axially in a main direction D0 from one axial end to the other axial end of the hoop layer 28. The main direction D0 forms an angle AF with the circumferential direction X of the tire 10, the absolute value of which is less than or equal to 10°, preferably less than or equal to 7°, more preferably less than or equal to 5°. In this case AF=-5°.

[0107] The radially inner working layer 24 is delimited axially by two axial ends. The radially inner working layer 24 comprises filamentary working reinforcing elements which extend axially from one axial end to the other axial end in a main direction D1 substantially parallel to each other. Similarly, the radially outer working layer 26 is delimited axially by two axial ends. The radially outer working layer 26 comprises filamentary working reinforcing elements which extend axially from one axial end to the other axial end in a main direction D2 substantially parallel to each other. Each of the main directions D1, D2 respectively form an angle AT1, AT2 with respect to the circumferential direction X of the tire 10, which have opposite senses. Each of the main directions D1, D2 respectively form an angle AT1, AT2 with respect to the circumferential direction X of the tire 10, the absolute value of which is strictly greater than 10°, preferably lying in the range of 15° to 50°, more preferentially lying in the range of 25° to 45°. In this case AT1=-33°, AT2=+33°.

[0108] The carcass layer 36 is axially delimited by two axial ends 361, 362. The carcass layer 36 comprises filamentary carcass reinforcing elements extending axially from one axial end 361, 362 to the other axial end in a main direction D3 that makes an angle AC with an absolute value greater than or equal to 60°, preferably in the range from 80° to 90°, with AC=+90°, relative to the circumferential direction X of the tire 10, in this case.

[0109] Each filamentous hoop reinforcing element, working reinforcing element and carcass reinforcing element is, for example, identical to those described in WO 2021 / 123522.

[0110] The tread 14 includes a tread surface 38 by which the tread 14 contacts the ground. The tread 14 includes a plurality of circumferential cuts, here a plurality of circumferential grooves, including first, second, third and fourth circumferential cuts designated by reference characters 52, 54, 56 and 58, respectively.

[0111] The tread 14 also includes a plurality of central ribs, here first, second and third central ribs, designated by reference characters 62, 64, 66, respectively. Each central rib 62, 64, 66 is axially disposed between and axially separated by two of adjacent circumferential cuts 52-58. The tread 14 also includes first and second lateral ribs 68, 70.

[0112] Although not visible in FIG. 1, each of the central ribs 62,64,66 and each of the side ribs 68,70 includes a transverse cut formed therein.

[0113] The tire comprises two sidewall inserts 90. Each sidewall insert 90 is arranged axially between the outer surface 31 of one of the sidewalls 30 and the inner surface 19 of said sidewall 30. More precisely, each sidewall insert 90 is arranged axially between the airtight inner liner layer 18 and the axially innermost carcass layer (in this case the single carcass layer 36). Each sidewall insert 90 has a generally crescent-shaped cross section.

[0114] Each sidewall insert 90 comprises at least one elastomer composition, called hard. In this case, each sidewall insert 90 comprises a hard elastomer composition 92, which in this particular case is made of the hard elastomer composition 92. The hard elastomer composition 92 of each sidewall insert 90 has a modulus of elasticity at 10% elongation MA10 of 6 MPa or more and 20 MPa or less, preferably 15 MPa or less and more preferably 13 MPa or less. In this case MA10=8 MPa. To compound this hard elastomer composition, for example, the teachings of WO 2014 / 184158 or WO 2018 / 111773 can be used.

[0115] Each sidewall insert 90 has a radially outer end 94 and a radially inner end 96. Each radially outer end 94 is disposed radially outward of the equator E, perpendicular to the inner surface 19, and radially and axially inward of a straight line N1 passing through each axially outer end 161, 162 of the axially widest crown layer of the crown reinforcement 16, in this case the hoop layer 28. Each radially inner end 96 is disposed radially inward of the equator E, perpendicular to the inner surface 19, and radially and axially outward of a straight line N2 passing through the radially outer end 33 of the outer surface 31 of each bead 32.

[0116] 2, the thickness of the hard elastomer composition 92, and therefore of the sidewall insert 90 in this case, is maximum radially outside the equator E. In this case, the thickness of the hard elastomer composition 92, and therefore of the sidewall insert 90 in this case, is maximum between, on the one hand, a radially outer straight line formed by a normal N3 to the inner surface 19 passing through a point 93 on the inner surface 19 located 10 mm radially outside of point I, and, on the other hand, a radially inner straight line formed by a normal N4 to the inner surface 19 passing through a point 95 on the inner surface 19 located 10 mm radially inside of this same point I. Point I is a point on each sidewall 30 that has a minimum thickness at this point I, and the thickness of the sidewall 30 at a point on the inner surface 19 is defined as the straight-line distance, along the normal N to the inner surface 19 at this point on the inner surface 19, between this point on the inner surface 19 and a point on the outer surface of the tire aligned with this point on the inner surface 19 along the normal N. In this case, point 97 is the point on the inner surface 19 where the thickness of the hard elastomeric composition 92, and therefore in this case the thickness of the sidewall insert 90, is at a maximum, and this point 97 on the inner surface 19 is located radially between the radially outer line N3 and the radially inner line N4. The radial distance D between point I and point 97 is equal to 7.6 mm.

[0117] The maximum thickness Emax of the hard elastomeric composition 92, and thus in this case the sidewall insert 90, is less than or equal to 5.0 mm, preferably in the range of 1.0 to 5.0 mm, more preferably 1.0 to 3.5 mm, even more preferably 1.0 to 2.5 mm, and most preferably 1.2 to 1.7 mm, where Emax=1.5 mm and the minimum thickness Emin of each sidewall 30 is Emin=6.5 mm.

[0118] Tyres according to second, third, fourth, fifth and sixth embodiments of the invention will now be described with reference to Figures 3 to 7 respectively, in which elements similar to those shown in the previous figures are designated by the same reference numerals.

[0119] Unlike the tire according to the first embodiment, the tire 10 according to the second embodiment of Fig. 3 is such that the carcass layer 36 anchored to each bead 32 is wound around the circumferential reinforcing elements 35 of each bead 32, in this case bead wires, such that the axially inner parts 3611, 3621 of the carcass layer 36 anchored to each bead 32 are arranged axially inside the axially outer parts 3612, 3622 of the carcass layer 36 anchored to each bead 32, and furthermore the axial ends 361, 362 axially delimiting the carcass layer 36 anchored to each bead 32 are arranged radially outside the circumferential reinforcing elements 35. The axial ends 361, 362 of the carcass layer 36 anchored to each bead 32 are arranged radially inside the equator E of the tire. More precisely, each axial end 361, 362 of the carcass layer 36 anchored to each bead 32 is located at a radial distance RNC of less than or equal to 30 mm from the radially inner end 351 of each circumferential reinforcing element 33 of each bead 32. In this case, RNC=23 mm.

[0120] Unlike the tire according to the second embodiment, the tire 10 according to the third embodiment of Fig. 4 is arranged such that the axial ends 361, 362 of the carcass layer 36 are arranged radially outward of the equator E. In this case, it is highly preferred that the axial ends 361, 362 of the carcass layer 36 are arranged axially inward of the axial ends 161, 162 of the hoop layer 28.

[0121] Unlike the tires according to the preceding embodiments, the carcass reinforcement 34 of the tire 10 according to the fourth embodiment of Fig. 5 comprises first and second carcass layers 36, 37 anchored to each bead 32 and extending radially in each sidewall 30 and axially in the crown 12 radially inside the crown reinforcement 16. The second carcass layer 37 is arranged axially outside the first carcass layer 36 at each sidewall and radially outside the first carcass layer 37 at the crown 12.

[0122] The second carcass layer 37 is axially delimited by two axial ends 371, 372. The second carcass layer 37 comprises filamentary carcass reinforcing elements extending axially from one axial end 371, 372 to the other axial end of the second carcass layer 37 along a main direction D4 that makes an angle AC with respect to the circumferential direction X of the tire 10 that is greater than or equal to 60° in absolute value, preferably ranging from 80° to 90°, here AC=+90°.

[0123] The sidewall insert 90 is disposed axially inward of the first carcass layer 36. A portion of each of the first and second carcass layers 36,37 is disposed axially between the circumferential reinforcing elements 38,40.

[0124] Unlike the tire according to the fourth embodiment, the tire 10 according to the fifth embodiment of Fig. 6 has the first carcass layer 36 arranged similarly to the second embodiment shown in Fig. 3. Furthermore, each axial end 371, 372 of the second carcass layer 37 is axially arranged between the axially inner portion 3611, 3621 and the axially outer portion 3612, 3622 of the first carcass layer 36. The second carcass layer 37 is arranged radially outward of the first carcass layer 36 in the crown 12.

[0125] As noted above in the general description of the application, other variations regarding the placement of the second carcass layer 37 are possible.

[0126] Different from the first and second embodiments, the tire 10 according to the sixth embodiment of Fig. 7 comprises two sidewall reinforcing layers 42, 43 extending at least radially in each sidewall 30 and having radially inner ends 421, 431 arranged radially inside the equator E and radially outer ends 422, 432 arranged radially outside the equator E. The tire 10 therefore comprises two sidewall reinforcing layers 42, 43 that are discontinuous under the crown 12.

[0127] Comparative Test

[0128] A comparison was made between a tire 10 according to the invention, according to a first embodiment, and a reference tire T1, not according to the invention, without a sidewall insert.

[0129] The tires 10 and T1 were tested to measure their cornering stiffness and their handling in a subjective test allowing the handling of the vehicle fitted with the tires to be evaluated.

[0130] The subjective tests were carried out on a circular circuit using a Range Rover Sport SVR vehicle fitted with two different tyres, T1 and T2, on the rear axle of which the load on the rear axle was equivalent to approximately 1576 kg, i.e. approximately 788 kg per tyre.

[0131] Concerning the cornering stiffness, Figure 8 shows the cornering stiffness Dz expressed in N / ° as a function of the applied load C expressed in N. The dashed line shows the evolution of the cornering stiffness of the control tire T1, and the continuous line shows the evolution of the cornering stiffness of the tire 10. It is noted that above a load approximately equal to 5000 N, the tire 10 according to the invention provides a significantly improved cornering stiffness compared to the control tire T1. It is noted that the higher the applied load, the more the cornering stiffness improves, especially at the load applied to each tire when the tires are mounted on the vehicle (7730 N in this case).

[0132] With regard to the subjective tests, the driver concluded that when the vehicle was fitted with the control tire T1, the vehicle was unstable in yaw and its cornering response was very non-linear. The rear axle was characterized by a lack of thrust, a long relaxation length and a lack of yaw damping. Relaxation length is a measure of the time it takes for cornering thrust to be established. When the vehicle was fitted with the tire 10 according to the invention, the driver concluded that the rear axle felt stiffer, resulting in a short relaxation length.

[0133] Thus, the subjective tests confirm the improvement in vehicle maneuverability due to increased cornering stiffness.

[0134] The present invention is not limited to the above-described embodiments. [Explanation of symbols]

[0135] 10 Tires 12 crowns 14 Tread 16 Crown Reinforcement 18 Airtight inner liner layer 19 Inner 20 Working Reinforcement 22 Hoop reinforcement 24 Radial inner working layer 26 Radial outer working layer 28 Hoop Layer 30 Sidewall 31 Exterior 32 Bead 33 Radial outer edge of the outer surface of each bead 34 Carcass reinforcement 36 Carcass layer 38 Tread surface 38 Axial inner circumferential reinforcing element 40 Axial outer circumferential reinforcement element 52 First circumferential cut 54 Second circumferential cut 56 3rd circumferential cut 58 4th circumferential cut 62 First center rib 64 Second center rib 66 Third center rib 68 First side rib 70 Second side rib 90 Sidewall Insert 92 Hard elastomer composition 94 Radially outer end of sidewall insert 96 Radially inner end of sidewall insert 161 Axial end of crown reinforcement 162 Axial end of crown reinforcement 361 Axial end of carcass layer 362 Axial end of carcass layer E Tire Equator M median plane N1 A straight line perpendicular to the inner surface and passing through the outer ends of each axial direction of the hoop layer N2 A straight line perpendicular to the inner surface and passing through the radially outer end of the outer surface of each bead X Circumferential direction of the tire Y Axial direction of the tire Z radial direction of the tire

Claims

1. A tire (10) for a passenger vehicle, comprising a crown (12), two beads (32), and two sidewalls (30) connecting each of the beads (32) to the crown (12), The tire (10) is a high load capacity type that complies with ETRTO Standard Manual 2021, The tire (10) comprises a sidewall insert (90) axially disposed between at least one outer surface (31) of the sidewall (30) and an inner surface (19) of the sidewall (30); said sidewall insert (90) comprises at least one elastomer composition (92) called hard, said or each hard elastomer composition (92) of said sidewall insert (90) having a modulus of elasticity at 10% elongation (MA10) of 6 MPa or more, and said hard elastomer composition (92) or the assembly of said hard elastomer compositions having a maximum thickness (Emax) of 5.0 mm or less; A tire (10) characterized in that

2. 2. A tyre (10) according to claim 1, wherein the or each hard elastomeric composition (92) has a modulus at 10% elongation (MA10) of less than or equal to 20 MPa.

3. 2. Tire (10) according to claim 1, wherein the maximum thickness (Emax) of the hard elastomeric composition (92) or of the mass of hard elastomeric compositions is in the range of 1.0 mm to 3.5 mm.

4. When the or each sidewall (30) has a minimum thickness (Emin) at point I, the thickness of said sidewall at a point on its inner surface (19) is defined as the straight-line distance, along a normal (N) to said inner surface (19) at said point on said inner surface (19), between said point on said inner surface (19) and a point on the outer surface (31) of the tire aligned with said point on said inner surface (19) along said normal (N); The point (97) on the inner surface (19) where the thickness of the hard elastomer composition (92) or the mass of hard elastomer composition is greatest is: - a radially outer straight line formed by a normal (N3) to the inner surface (19) passing through a point (93) on the inner surface (19) located 10 mm radially outside of point I; - a radially inner straight line formed by a normal (N4) to the inner surface (19) passing through a point (95) on the inner surface (19) located 10 mm radially inside of point I; The tire (10) of claim 1, wherein the tire (10) is radially disposed between

5. 2. The tire (10) of claim 1, wherein the thickness of the hard elastomeric composition (92) or of the mass of hard elastomeric compositions is greatest radially outward of the equator (E) of the tire.

6. The tire (10) of claim 1, wherein a radially outer end (94) of the sidewall insert (90) is disposed radially outward of an equator (E) of the tire.

7. The tire (10) of claim 1, wherein a radially inner end (96) of the sidewall insert (90) is disposed radially inward of an equator (E) of the tire.

8. 2. The tire (10) of claim 1, comprising a carcass reinforcement (34) including at least one carcass layer (36) anchored to the or each bead (32) and extending radially within the or each sidewall (30) and axially within the crown (12) radially inward of the crown reinforcement (16).

9. 9. The tire (10) of claim 8, comprising an inner liner layer (18) supporting the inner surface (19) of the tire, the sidewall insert (90) being axially disposed between the inner liner layer (18) and the axially innermost carcass layer (36).

10. 2. The tire (10) of claim 1, having a sidewall height H defined as H=SW*AR / 100, where SW is the nominal section width and AR is the nominal aspect ratio of the tire, and a load index LI satisfying H / LI≧0.85, where SW, AR, and LI are defined in accordance with ETRTO Standards Manual 2021.

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