Heavy-duty tire with molded elements

Abstract

The present invention relates to a tire of the HIGH LOAD CAPACITY type for passenger cars, comprising a smooth reference surface (44) and at least one molding element (46) concave and at least one molding element convex relative to the smooth reference surface (44). The maximum thickness Emax, the maximum depth Pmax of each concave molding element (46) and / or the maximum height Hmax of each convex molding element satisfy Emax^(0.4) x Pmax ≦ 1.1 and Emax^(0.4) x Hmax ≦ 1.1, Pmax and Hmax being expressed in mm. Emax is the maximum distance between the axially outermost reinforcing layer (36) and the smooth reference surface (44). Emax is equal to or less than 3.0 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. The tire is commercially available as the MICHELIN (trademark) Pilot Sport 4 series, and has a size of 255 / 35R18. The tire has an EXTRA-LOAD (abbreviated as XL) version as specified in the ETRTO Standard Manual 2019, and the EXTRA-LOAD version has a load index equal to 94. That is, at a pressure of 290 kPa, the tire can support a load of 670 kg. This load-bearing performance is relatively high compared to a tire of the same size called STANDARD LOAD (abbreviated as SL), which has a load index equal to 90 and can support 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 described 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 is a 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" 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 the HIGH LOAD CAPACITY type has a load index equal to 98, indicating that it can withstand a load of 750 kg at a pressure of 290 kPa.

[0014] When using these HIGH LOAD CAPACITY tires, it has been observed that cracks appear on the sidewall surface of the tire, especially in the upper radial direction included between the equator of the tire on the one hand and the normal to the inner surface passing through the circumferential boundary line marking the boundary between the sidewall and the crown on the other hand. It has been noticed that these cracks appear especially when driving over deep potholes or large bumps in the road, when riding over curbs suddenly, when using inflation pressures significantly lower than the recommended pressure, or when using the tire under loads significantly higher than the maximum load.

[0015] While such cracks do not pose a danger to the tire user, they do mar the tire's appearance and therefore its aesthetic appeal, and may also cause unnecessary anxiety to tire users. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] International Publication No. 2021 / 123522 [Patent Document 2] European Patent No. 1954463 [Patent Document 3] European Patent No. 2204296 [Patent Document 4] European Patent No. 2483088 [Patent Document 5] European Patent No. 2483088 [Patent Document 6] International Publication No. 2012 / 131089 [Patent Document 7] International Publication No. 2021 / 250331 [Patent Document 8] International Publication No. 2019 / 097175 [Patent Document 9] International Publication No. 2018 / 100080 [Patent Document 10] International Publication No. 2018 / 091841 [Patent Document 11] International Publication No. 2019 / 229323 Summary of the Invention [Problem to be solved by the invention]

[0017] The object of the present invention is to provide a tire that can withstand higher loads than existing tires and at the same time reduce or eliminate the risk of sidewall cracking. [Means for solving the problem]

[0018] The subject of the invention is therefore a passenger tyre comprising a crown, two beads and two sidewalls connecting each bead to the crown, at least one of the sidewalls comprising at least one reinforcing layer including reinforcing elements embedded in a polymer matrix, the or each sidewall comprising: -The tire equator and a normal to the inner surface, passing through a circumferential boundary line that marks the interface between the sidewall and the crown; a radially upper portion radially included between The upper part in the radial direction is a smooth reference surface; at least one shaped concave element and / or at least one shaped convex element, which is concave or convex relative to a smooth reference surface; and having an outer surface comprising The tire (10) is a HIGH LOAD CAPACITY type that complies with the ETRTO Standard Manual 2021. The maximum thickness Emax, the maximum depth Pmax of the or each formed concave element in the radial direction relative to a smooth reference surface, and / or the maximum height Hmax of the or each formed convex element in the radial direction relative to a smooth reference surface satisfy Emax^(0.4) x Pmax ≦ 1.1 and Emax^(0.4) x Hmax ≦ 1.1, Emax, Pmax and Hmax being expressed in mm; Emax is measured at the top radial direction along a line perpendicular to the inner surface, - in the radial upper part, an axially outer surface passing through the axially outermost points of each reinforcing element of the or each part of the or each axially outermost reinforcing layer; a smooth reference surface; and Emax is 3.0 mm or less.

[0019] According to the present 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 a marking on at least one of the sidewalls indicating the size of the tire in the form of X / YαVUβ in accordance with the marking of the ETRTO Standards Manual 2021, where X represents the nominal section width, Y represents the nominal aspect ratio, α represents the structure and may be R or ZR, V represents the nominal rim diameter, U represents the load index, and β represents the speed symbol.

[0020] By increasing the load index of the tire according to the invention compared to the load index of a tire of the same size in the EXTRA-LOAD version, the invention allows the tire-wheel assembly to increase its load-bearing capacity without changing the capacity, compactness and comfort of the vehicle in which it is used. In particular, since the size of the tire according to the invention is the same as that of the tire in the EXTRA-LOAD version, the tire-wheel assembly does not take up more space than the tire in the EXTRA-LOAD version. The tire of the invention can be marked with a distinctive marking, for example with the marking HL (HIGH LOAD) or XL+ (EXTRA LOAD+), so as to distinguish it from its STANDARD LOAD and EXTRA-LOAD versions. Such markings are disclosed in particular in the ETRTO Standards Manual 2021, on page 3 in the section "General Notes - Tires for Passenger Cars". Also, examples of sizes of tires of the HIGH LOAD CAPACITY type are disclosed in the ETRTO Standards Manual 2021, on page 44, in the section "Tires for Passenger Cars - Tires by Metric Designation", in paragraph 9.1.

[0021] 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 Designation", 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.

[0022] The inventors behind the present invention understand that due to the relatively high loads that HIGH LOAD CAPACITY type tires must withstand, the radially upper portion of the sidewall is subject to very high stresses, especially during the high stress events mentioned above. This radially upper portion includes the portion of the outer surface of the sidewall that has the smallest radius of curvature during a high stress event, resulting in high stress concentrations. This portion of the outer surface of the sidewall can be easily identified, for example, by inflating the tire to a pressure below the nominal pressure and subjecting it to a load significantly higher than the nominal load, for example 120% or more of the nominal load (the pressures and nominal loads are those indicated in the ETRTO Standards Manual 2021).

[0023] The inventors have also realized that these extremely high stresses are localized near areas of the sidewall that exhibit very large local thickness variations.

[0024] Thus, the inventors have found that by reducing these local thickness variations that are essentially present in the vicinity of concave or convex molding elements present on the outer surface of the radially outer portion, for example in the form of imprints, the risk of sidewall cracking is reduced or even eliminated.

[0025] The inventors have also observed that the greater the maximum thickness Emax of a HIGH LOAD CAPACITY type tire, the more sensitive the sidewall is to the appearance of the above-mentioned cracks. Thus, the inventors have determined relationships that make it possible either to limit the maximum depth Pmax or the maximum height Hmax of the moulding elements for a given maximum thickness Emax, or to limit the maximum thickness Emax for a given maximum depth Pmax and / or a given maximum height Hmax of the moulding elements.

[0026] In addition to satisfying the relationship determined by the inventors, the maximum thickness Emax will be reduced as much as possible to reduce the risk of cracking, which, as mentioned above, increases with increasing maximum thickness Emax.

[0027] The concave or convex molding elements include, in particular, inscriptions, vent spew hairs and / or vent spew holes, preferably selected from among these elements. The inscriptions include, in particular, regulatory inscriptions, decorative inscriptions and tire monitoring inscriptions, preferably selected from among these elements. The regulatory inscriptions include, in particular, regulatory inscriptions required by various regulations, including, inter alia, the tire manufacturer, the commercial name and the DOT number. The decorative inscriptions include inscriptions essentially for decorating the appearance of the tire. The tire monitoring inscriptions include, in particular, coded matrix symbols (QR Codes (registered trademark)).

[0028] Bent pew hairs are elements molded as protrusions having an elongated shape that result from the elastomer composition that supports the tire's outer surface escaping into vent holes in the mold while the tire is being molded. Similarly, vent pew holes are elements molded as recesses having the general shape of a well when the tire is molded.

[0029] The circumferential boundary line between the sidewall and the crown is generally a molded line since it corresponds to the boundary between the two mold elements used to mold the sidewall and the crown. If there are multiple circumferential lines, the circumferential boundary line is the radially innermost circumferential line. If there are no molded lines, the boundary line between the sidewall and the crown is generally the - A radial distance, measured from the radially inner edge of the tyre, equal to 65% of the tyre's sidewall height H (for tyres with H<95), - A radial distance, measured from the radially inner edge of the tyre, equal to 70% of the tyre's sidewall height H (for tyres with H ≥ 95), It is an imaginary circumferential line located at the position.

[0030] The sidewall height H is 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, e.g., as set forth in the ETRTO Standards Manual 2021.

[0031] A smooth surface is a surface of a tire that does not have any concave or convex molding elements and that follows the curvature of the tire's outer surface without any sharp local variations. This smooth surface serves as a reference for determining the maximum depth Pmax and / or the maximum height Hmax. A smooth reference surface is therefore an entity formed by a smooth surface passing through the surface of the tire without any concave or convex molding elements, as well as by a virtual surface that follows the curvature of the tire's outer surface forming an uninterrupted continuation of the smooth surface, without taking into account any concave or convex molding elements. The smoothness of a reference surface characterizes it in that it has a much smaller roughness than the molding elements, and in any case a roughness that is not perceptible to the human touch. In general, a smooth reference surface is characterized by a lightness that is much greater than the lightness of the molding elements that themselves have to be contrasted with this smooth reference surface.

[0032] Molding elements are elements that are formed as one material with the rest of the tire sidewall during tire molding. Each concave or convex molding element is continuous. Thus, as soon as two concave elements or two convex elements are at least partially in contact with each other and are joined to each other by an element that is also concave or convex, these concave or convex elements will all be considered to be joined together and form one and the same single concave or convex molding element. In contrast, as soon as two concave elements or two convex elements are completely cut off from each other and separated from each other by a part of a smooth reference surface, these two concave elements or two convex convex elements will be considered to be two different molding elements.

[0033] The maximum depth Pmax of the concave molding element under consideration is the maximum of the distances measured between the smooth reference plane and the various points on the bottom surface of the concave molding element.Similarly, the maximum height Hmax of the convex molding element under consideration is the maximum of the distances measured between the smooth reference plane and the various points on the outer surface of the convex molding element.

[0034] Preferably, the radially upper portion extends circumferentially continuously around the entire circumference of the tire.

[0035] Outside the upper radial portion, there may be other concave or convex molding elements on the tire sidewall. These other molding elements may not follow the relationships we have determined. In particular, the stresses outside the upper radial portion are not as high, so there is less or no risk of cracking.

[0036] The maximum radial upper thickness Emax is the maximum value of the radial upper thickness and can be constant or variable.

[0037] For each reinforcing layer of the or sidewall, a continuous surface is defined, called the axially outer surface (SAE) of the layer, passing through the axially outermost points of each reinforcing element, and a continuous surface, called the axially inner surface (SAI) of the layer, passing through the axially innermost points of each reinforcing element.

[0038] In some embodiments, the radial top comprises a single, identical, axially outermost reinforcing layer throughout its radial height. In other embodiments, the radial top comprises multiple reinforcing layers that are axially outermost depending on the point in its radial height. In these other embodiments, the axially outer surface SAE used to calculate the maximum distance Emax is the axially outer surface of each portion of each axially outermost reinforcing layer relative to the point in the radial height where the thickness between the axially outer surface and the smooth surface is measured.

[0039] The expression "reinforcing element" means an element that provides mechanical reinforcement to the polymer matrix in which it is intended to be embedded.

[0040] Preferably, the reinforcing elements are 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.

[0041] The matrix is ​​said to be polymeric because it is based on a polymer composition, for example one or more polymers chosen from thermoplastic polymers, thermosetting polymers, elastomers, thermoplastic elastomers, but also fillers and other components routinely used in the field of tire compositions, in particular compositions for embedding reinforcing elements.

[0042] The inner surface defines an interior cavity of the tire that is intended to be pressurized with inflation gas once the tire is mounted on a mounting support, such as a rim.

[0043] The exterior 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.

[0044] The tyre according to the invention has a substantially toroidal shape about an axis of rotational symmetry substantially coinciding with the axis of rotation of the tyre, which axis of rotational symmetry defines the three directions conventionally used by those skilled in the art: axial, circumferential and radial.

[0045] The expression "axial" means the axis of rotational symmetry of the tire, i.e. a direction substantially parallel to the axis of rotation of the tire.

[0046] 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).

[0047] 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.

[0048] 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.

[0049] 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 (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 be in contact with the ground and the radially innermost point of the tire intended to be in contact with a support, for example the rim, the distance between these two points being equal to H.

[0050] The expression "meridian plane" means a plane parallel to and containing the axis of rotation of the tire and perpendicular to the circumferential direction.

[0051] 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.

[0052] "Bead" means the part of a 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 come into contact with the flange of the rim enabling the mounting of the tire.

[0053] An interval 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 an interval 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).

[0054] In embodiments that allow for a reduced risk of cracking, the radially upper portion bearing the outer surface comprises one or more concave forming elements and / or one or more convex forming elements, at least some of the concave forming elements or at least some of the convex forming elements or at least some of the convex forming elements are such that Emax^(0.4) x Pmax > 1.1 and Emax^(0.4) x Hmax > 1.1. In these embodiments, the invention applies only to the part of the forming elements in the radially upper portion.

[0055] In embodiments that allow further reducing the risk of cracking, the radially upper portion bearing the outer surface comprises one or more concave forming elements and / or one or more convex forming elements, the concave forming element or all of the concave forming elements or the convex forming element or all of the convex forming elements are such that Emax^(0.4) x Pmax ≦ 1.1 and Emax^(0.4) x Hmax ≦ 1.1. In these embodiments, the invention applies to all of the forming elements in the radially upper portion.

[0056] In certain embodiments that allow for a reduced risk of cracking, bearing in mind the relatively small size of the vented pew hairs and vented pew holes, the concave and / or convex molding elements to which the present invention relates are concave and / or convex molding elements excluding vented pew hairs and vented pew holes.

[0057] In some embodiments, the concave and / or convex molding elements to which the invention pertains comprise concave and / or convex molding elements that include circumferentially oriented lines, where lines refer to lines that separate the concave and / or convex molding elements. Thus, the characters are separated by lines oriented in different directions, one or more of which are oriented in the circumferential direction. Other examples include stripe-like inscriptions that can be circumferentially oriented.

[0058] In an advantageous embodiment making it possible to reduce the risk of cracking, Emax^(0.4)×Pmax≦0.9 and Emax^(0.4)×Hmax≦0.9, more preferentially Emax^(0.4)×Pmax≦0.8 and Emax^(0.4)×Hmax≦0.8, and even more preferentially Emax×Pmax≦0.6 and Emax×Hmax≦0.6.

[0059] The tire is intended for passenger vehicles as defined in the ETRTO Standards Manual 2021. Such tire has, in meridian section, a cross section characterized by a section height H and a nominal section width S as intended by the ETRTO Standards Manual 2021, optionally with an aspect ratio H / S expressed as a percentage at most equal to 90 and at least equal to 20, and with the nominal section width S at least equal to 225 mm and at most equal to 385 mm. Furthermore, the flange diameter D, which defines the diameter of the rim on which the tire is mounted, is optionally at least 16 inches and at most 24 inches. Finally, further optionally, the load index LI is in the range from 98 to 116.

[0060] In some advantageous embodiments making it possible to reduce the risk of cracking, the or each radially upper part of the sidewall bears against the outer surface of said radially upper part of the sidewall and comprises an elastomeric composition having a modulus of elasticity at 10% elongation of less than or equal to 10 MPa, preferably less than or equal to 5 MPa, and more preferentially ranging from 1 MPa to 5 MPa. The higher the risk of cracking of the tire, the more preference there will be given to an elastomeric composition having a lower modulus of elasticity at 10% elongation.

[0061] The elastomeric composition supporting the outer surface specifies the elastomeric composition that is in contact with air at atmospheric pressure and is visible from the outside of the tire. Thus, in an embodiment in which the radially upper portion of the sidewall comprises a plurality of elastomeric compositions arranged axially side by side, it is the modulus at 10% elongation of the axially outermost composition supporting the outer surface that is characterized.

[0062] The elastomeric composition supporting the outer surface is based on one or more elastomers. It may also contain fillers and other ingredients routinely used in the field of tire compositions.

[0063] 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% (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.

[0064] In some optional embodiments, Pmax is 0.8 mm or less, preferably 0.5 mm or less, and Hmax is 0.8 mm or less, preferably 0.5 mm or less. In order to eliminate the risk of cracking, it is preferred that the maximum depth Pmax and / or maximum height Hmax are as small as possible, in addition to satisfying the relationships determined by the inventors.

[0065] In some advantageous but optional embodiments, Pmax is 0.3 mm or more and Hmax is 0.3 mm or more. Since the contrast between the molding elements is all the greater the greater the maximum depth Pmax and / or the greater the maximum height Hmax, a sufficient maximum depth Pmax and / or maximum height Hmax is preferred.

[0066] In some advantageous but optional embodiments, Emax is equal to or greater than 1.0 mm, and preferably ranges from 1.5 mm to 2.5 mm.

[0067] Advantageously, the tire has a sidewall height H defined by 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 0.72≦H / LI≦0.85, preferably 0.72≦H / LI≦0.90, where SW, AR and LI are defined in accordance with the ETRTO Standards Manual 2021. The invention is therefore preferably applied to tires that are expected to have relatively large deflections, since they have, in terms of this load index, a relatively high load index for a relatively low sidewall height. In particular, in such cases, the radially outer portion of the sidewall forms a relatively short hinge that is subject to large deflections, especially in the high stress situations described herein above, and is therefore very susceptible to the appearance of cracks.

[0068] The nominal section width SW, the nominal aspect ratio AR and the load index LI are specifically indicated in the size marking in accordance with the ETRTO Standards Manual 2021 on the sidewall of the tire.

[0069] In a first configuration, the tire comprises a carcass reinforcement including at least one carcass ply anchored to each bead, the crown comprises a crown reinforcement, the carcass ply anchored to each bead extends radially in each sidewall and axially in the crown radially inward of the crown reinforcement, the or each portion of the or each axially outermost reinforcing layer is formed by at least a portion of the carcass ply anchored to each bead and is radially upper and axially outermost.

[0070] In a first variant of the first configuration, the carcass reinforcement comprises a single carcass ply anchored in each bead.

[0071] In a particular embodiment of this first variant, the carcass layer anchored in each bead is wrapped around the circumferential reinforcing element of each bead such that an axially inner portion of the carcass layer anchored in each bead is arranged axially inside an axially outer portion of the carcass layer anchored in each bead, and each axial end of the carcass layer anchored in each bead is arranged radially outside a respective circumferential reinforcing element, the or each portion of the or each axially outermost reinforcing layer is formed by at least a part of its radially upper and axially innermost portion; and / or the or each portion of the or each axially outermost reinforcing layer is formed by at least a part of its radially upper, axially outermost portion;

[0072] In another embodiment of this first variant, 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.

[0073] In a second variant of the first configuration, the carcass reinforcement comprises first and second carcass layers anchored in each bead.

[0074] In a particular embodiment of this second variant, the first carcass layer is wrapped around the circumferential reinforcing element of each bead such that an axially inner portion of the first carcass layer is positioned axially inside an axially outer portion of the first carcass layer, each axial end of the first carcass layer is positioned radially outside each circumferential reinforcing element, and each axial end of the second carcass layer is positioned radially inside each axial end of the first carcass layer.

[0075] In a first variant of these embodiments, each axial end of the second carcass layer is arranged axially between the axially inner and outer portions of the first carcass layer, and the or each portion of the axially outermost reinforcing layer is formed by at least a portion of the second carcass layer at the radially upper portion. In this first variant, the second carcass layer is arranged radially outside the first carcass layer in the crown.

[0076] In a second variant of these embodiments, the axial ends of the second carcass layer are arranged axially inside the axially inner portions of the first carcass layer, and the or each portion of the axially outermost reinforcing layer is formed by at least a portion of the first carcass layer at the radially upper portion. In this variant, the second carcass layer is arranged radially inside the first carcass layer in the crown and axially inside the first carcass layer in each sidewall.

[0077] In a third variant of these embodiments, the axial ends of the second carcass layer are arranged axially outside the axially outer portions of the first carcass layer, and the or each portion of the axially outermost reinforcing layer is formed by at least a portion of the second carcass layer at the radially upper portion. In this variant, the second carcass layer is arranged radially outside the first carcass layer in the crown and axially outside the first carcass layer in each sidewall.

[0078] In another embodiment of this second variant, each bead comprises a plurality of circumferential reinforcing elements and at least a portion of each of the first and second carcass layers is axially arranged between at least two of the plurality of circumferential reinforcing elements, as described, for example, in WO 2021 / 123522.

[0079] In a second configuration, the tire comprises: a carcass reinforcement comprising at least one carcass ply anchored to each bead, the crown comprising a crown reinforcement, the carcass ply anchored to each bead extending radially in each sidewall and axially in the crown radially inward of the crown reinforcement; A sidewall reinforcing layer disposed axially outward of the carcass reinforcement; Equipped with The or each portion of the axially outermost reinforcing layer is formed radially above by at least a part of the sidewall reinforcing layer.

[0080] Unlike the carcass layer, which is anchored to each bead, the sidewall reinforcing layer is not anchored to each bead. Thus, each radially inner end of the sidewall reinforcing layer is disposed radially outward of each bead. The sidewall reinforcing layer extends at least radially within each sidewall, a radially inner end disposed radially inward of an equator of the tire; a radially outer end disposed radially outward of an equator of the tire; has.

[0081] In a particular embodiment in which the carcass layer or the first carcass layer forms a turn, the axial ends of said carcass layer are arranged radially inside the equator of the tire, and even more preferably at a radial distance of not more than 30 mm from the radially inner end of the circumferential reinforcing element of each bead. By arranging the axial ends of the carcass layer or the first carcass layer inside the equator of the tire, the mass of the carcass reinforcement is significantly reduced. Moreover, the majority of rims currently used for passenger tires have a J-shaped rim flange that is in all cases less than 30 mm high. The highly preferential arrangement of the axial ends in a region substantially corresponding radially to the rim flange makes it possible to mechanically protect them. In particular, if the axial ends are arranged too high radially above the circumferential reinforcing elements of each bead, i.e. at a radial distance strictly more than 30 mm from the radially inner end of the circumferential reinforcing element, they will be located in a flexible region of the tire that is subjected to excessively high stresses, which stresses are particularly high for tires of the HIGH LOAD CAPACITY type.

[0082] In another embodiment in which the carcass layer or the first carcass layer forms a turn, the axial ends of said carcass layer are arranged radially outside the equator of the tire. Advantageously, in these other embodiments, the axial ends of the carcass layer or the first carcass layer are arranged with a high degree of preference axially inside the axial end of at least one of said crown layer or crown layers of the crown reinforcement.

[0083] Optionally, the or each carcass layer anchored in each bead comprises a carcass reinforcing element bounded axially by two axial ends of the carcass layer and extending axially from one axial end of the carcass layer to the other axial end of the carcass layer.

[0084] Optionally, each carcass reinforcing element extends in a main direction which forms an angle, in absolute value, with the circumferential direction of the tire of greater than or equal to 60°, preferably ranging from 80° to 90°.

[0085] In some embodiments, the crown comprises a crown reinforcement including a radially inner working layer and a radially outer working layer disposed radially outward of the radially inner working layer.

[0086] Optionally, each working layer comprises working reinforcing elements bounded axially by two axial ends of the working layer and extending axially from one axial end of the working layer to the other axial end of the working layer substantially parallel to each other.

[0087] Optionally, each working reinforcing element extends along a main direction which makes an angle with the circumferential direction of the tire strictly greater than 10° in absolute value, preferably in the range from 15° to 50°, more preferably in the range from 20° to 35°.

[0088] Preferably, in an embodiment in which the working reinforcement comprises a radially innermost working layer and a radially outermost working layer arranged radially outside the radially innermost layer, the main directions in which each working reinforcing element of the radially innermost working layer extends and the main directions in which each working reinforcing element of the radially outermost working layer extends form opposite angles with respect to the circumferential direction of the tire.

[0089] Optionally, the crown reinforcement comprises a hoop reinforcement comprising at least one hoop reinforcement element axially separated by two axial ends of the hoop reinforcement and spirally wound circumferentially so as to extend axially between the axial ends of the hoop reinforcement.

[0090] Preferably, the hoop reinforcement is located radially outward of the working reinforcement.

[0091] Advantageously, the or each hoop reinforcing element extends in a main direction which makes an angle with the circumferential direction of the tire of less than or equal to 10°, preferably less than or equal to 7° and more preferentially less than or equal to 5° in absolute value.

[0092] Suitably the or each carcass, working and hoop reinforcing element is a thread-like reinforcing element.

[0093] In an advantageous embodiment, the or each concave shaping element and / or the or each convex shaping element has a lightness L in the range from 6 to 15, preferably in the range from 8 to 10. * 1, and the smooth reference surface has a lightness L ≥ 18, preferably in the range of 18 to 30. * 2. These advantageous embodiments make it possible to obtain a relatively high level of contrast even when the maximum depth Pmax and / or maximum height Hmax are relatively small. In particular, in general, all other factors being equal, the smaller the maximum depth Pmax and / or maximum height Hmax, the lower the contrast between the shaping element and the smooth reference surface.

[0094] Thus, a strong contrast between the shaped elements and the smooth reference surface is guaranteed. By "lightness" is meant the parameter that characterizes the ability of a circuit to reflect light. Lightness is defined as the L value adopted by the International Commission on Illumination (CIE) in 1976. * a * b * According to the color model, it is expressed using a scale from 0 to 100, where a value of 100 represents white or total reflection and a value of 0 represents black or total absorption. * 1 and L * 2 is measured using a spectrophotometer, for example a Konica Minolta CM700D spectrophotometer. This instrument is positioned above the area whose lightness is to be measured and the lightness of this area is measured directly. This measurement is made in particular using the SCI (specular component included) mode, with an angle set at 10° and with D65 type illuminant settings (settings defined by the CIE). Lightness L * To improve the determination of 2, it is possible to make several measurements on the tire and from them infer the average lightness of the smooth reference surface.

[0095] In some advantageous embodiments, the or each concave shaping element and / or the or each convex shaping element has a texture comprising a plurality of elements protruding relative to a bottom surface of the concave shaping element and / or the convex shaping element.

[0096] Optionally, the protruding elements of the plurality of protruding elements are separate and distinct elements spread across the texture at a density equal to at least one element per square millimeter. In one variation, the plurality of protruding elements comprises threads, each thread having a length of 0.003 mm. 2 and 1mm 2 and . Examples of strands are described, for example, in EP 1954463, EP 2204296 or EP 2483088. In another variant, the plurality of projecting elements are configured as ridges, as can be found in Dunlop tires sold under the name V EURO. In another variant, the plurality of projecting elements are configured as stars, as can be found in Bridgestone tires sold under the name POTENZA SPORT.

[0097] Optionally, the protruding elements of the plurality of protruding elements are lamellae substantially parallel to one another, the spacing of the lamellae in the texture being at most equal to 0.5 mm, and each lamellae having an average width between 0.03 mm and 0.25 mm. Examples of lamellae are described, for example, in EP 2 483 088 and WO 2012 / 131089.

[0098] The invention will be understood more clearly 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]

[0099] [Figure 1] 1 is a meridian section of a tire according to a first embodiment of the invention; FIG. [Diagram 2] 2 is a side view of the outer surface of the tire of FIG. 1 in the direction II-II' shown in FIG. 1. [Diagram 3] 3 is a detailed view of meridian section III-III' shown in FIG. 2, illustrating a radially outer portion of a sidewall of the tire of FIG. 1; FIG. [Figure 4] 4 is a detailed view of meridian section IV-IV' shown in FIG. 2, illustrating the radially outer portion of the sidewall of the tire of FIG. 1; FIG. [Diagram 5]FIG. 2 is a view similar to FIG. 1 for a tire according to a second embodiment. [Figure 6] FIG. 2 is a view similar to FIG. 1 for a tire according to a third embodiment. [Figure 7] FIG. 2 is a view similar to FIG. 1 for a tire according to a fourth embodiment. [Figure 8] FIG. 2 is a view similar to FIG. 1 for a tire according to a fifth embodiment. [Figure 9] FIG. 2 is a view similar to FIG. 1 for a tire according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0100] Reference systems X, Y, Z are shown in the figures corresponding to the conventional axial (Y), radial (Z) and circumferential (X) directions of the tire or tire-wheel assembly, respectively.

[0101] Figure 1 shows a tire according to the invention, designated by the general reference number 10. The tire 10 has a substantially toroidal shape about an axis of rotation substantially parallel to an axial direction Y. The tire 10 is intended for passenger cars and has the dimensions 255 / 35R20. In the various figures, the tire 10 is shown as new, i.e. before it has been driven.

[0102] The tire 10 comprises a crown 12 with a tread 14 intended to come into contact with the ground when running, and a crown reinforcement 16 extending in the crown 12 in a circumferential direction X. The tire 10 also comprises an airtight inner liner 18 which is impermeable to inflation gas and which, once the tire 10 is mounted on a mounting support, for example a rim, is intended to define, together with the mounting support of the tire 10, an internal cavity which is intended to be pressurized with inflation gas. This airtight inner liner 18 bears against an inner surface 19 of the tire 10.

[0103] The crown reinforcement 16 includes a working reinforcement 20 and a hoop reinforcement 22. The working reinforcement 16 includes at least one working layer, and in this case includes two working layers, a radially outer working layer 26 and a radially inner working layer 24 disposed radially inwardly thereof.

[0104] The hoop reinforcement 22 comprises at least one hoop layer, in this case one hoop layer 28 .

[0105] 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.

[0106] The tire 10 includes two sidewalls 30 that continue radially inwardly from the crown 12. The tire 10 also includes two beads 32 radially inwardly of the sidewalls 30. Each sidewall 30 connects a respective bead 32 to the crown 12.

[0107] 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 within each sidewall 30 and axially within the crown 12, radially inward of the crown reinforcement 16.

[0108] The carcass layer 36 anchored to each bead 32 is wound around the circumferential reinforcing element 33 of each bead 32 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 the axial ends 361, 362 axially delimiting the carcass layer 36 anchored to each bead 32 are arranged radially outside the circumferential reinforcing element 33. 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 331 of each circumferential reinforcing element 33 of each bead 32. In this case, RNC=23 mm.

[0109] 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, in this case thread-like reinforcing elements, are embedded. Each thread-like hoop reinforcing element, working reinforcing element and carcass reinforcing element is, for example, identical to those described in WO 2021 / 250331 A1.

[0110] The hoop reinforcement 22, here the hoop layer 28, is axially delimited by two axial ends 281, 282. The hoop reinforcement 22 comprises one or more filamentary hoop reinforcing elements wound helically in the circumferential direction, extending axially from one axial end to the other in a main direction D0, which main direction D0 forms an angle with the circumferential direction X of the tire that is less than or equal to 10°, preferably less than or equal to 7°, more preferably less than or equal to 5° in absolute value, in this case AF=-5°.

[0111] The radially inner working layer 24 is delimited axially by two axial ends 241, 242. 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 261, 262. 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 has an opposite sense. 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 is strictly greater than 10° in absolute value, preferably lying in the range from 15° to 50°, more preferentially lying in the range from 20° to 35°. In this case, AT1 = -26° and AT2 = +26°.

[0112] The carcass layer 36 comprises filamentary carcass reinforcing elements extending axially from one end to the other in a main direction D3 which forms with the circumferential direction X of the tire 10 an angle AC greater than or equal to 60°, preferably ranging from 80° to 90°, in absolute value, where AC=+90°.

[0113] Each sidewall 30 carries an inscription indicating the size of the tire 10 as well as a speed rating and a speed code. In this case, the tire 10 has a nominal section width SW equal to 255, a nominal aspect ratio AR equal to 35 and a nominal rim diameter equal to 20. The tire 10 therefore has a sidewall height H defined by SW x AR / 100, which in this case is equal to 89. According to the invention, the inscription also includes 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 2019. Preferably, LI' + 1 ≤ LI ≤ LI' + 4, and even LI' + 2 ≤ LI ≤ LI' + 4. A tire of size 225 / 35R20 in the EXTRA-LOAD version has a load index equal to 97, as indicated on page 36 of the ETRTO Standards Manual 2019 in the section "Passenger Car Tires - Tires with Metric Designations". The load index LI of the tire 10 is therefore such that LI≧98, preferably 98≦LI≦101, or even 99≦LI≦101, in which case LI=100. This load index equal to 100 corresponds to the load index of a HIGH LOAD CAPACITY tire of size 255 / 35R20, as indicated in the ETRTO Manual 2021. The tire 10 is therefore indeed of the HIGH LOAD CAPACITY type.

[0114] The tire 10 is such that 0.72≦H / LI≦0.95, preferably 0.72≦H / LI≦0.90, where H / LI=0.89.

[0115] 1-4, each sidewall 30 includes a radial upper portion 38 radially included between the tire's equator E and an inner surface normal N passing through a circumferential boundary line 40 that marks the boundary between each sidewall 30 and the crown 12. The radial upper portion 38 has an outer surface 42, visible in FIG. 2, that includes a smooth reference surface 44, a concave molding element 46, and a convex molding element 47. In the example shown in FIG. 2, the concave molding element 46 includes a regulatory inscription "R20" and the convex molding element 47 includes a "Tire Manufacturer's Name (TIRE Co.)" inscription and a decorative inscription stripe including circumferentially oriented lines.

[0116] Each sidewall 30 also includes a molding element 48 disposed outwardly of the outer surface 42 of the radially upper portion 38 .

[0117] As shown in Figures 3 and 4, the radially upper portion 38 comprises an elastomeric composition 50 bearing on its outer surface 52. The elastomeric composition 50 has an elastic modulus MA10 at 10% elongation of less than or equal to 10 MPa, preferably less than or equal to 5 MPa, more preferentially in the range of 1 MPa to 5 MPa. In this case, MA10 = 3 MPa. Examples of compositions meeting these MA10 elastic modulus values ​​are the control composition T1 of WO 2019 / 097175, Comparative Example A described in WO 2018 / 100080, the compositions described in WO 2018 / 091841 and WO 2019 / 229323.

[0118] Each sidewall 30 comprises a reinforcing layer including reinforcing elements embedded in a polymer matrix, in this example a carcass layer 36 including carcass reinforcing elements 360 embedded in a polymer matrix 363. The carcass layer 36 comprises an axially outer surface SAE passing through the axially outermost point of each carcass reinforcing element 360 and an axially inner surface SAI passing through the axially innermost point of each carcass reinforcing element 360. The carcass layer 36 is separated from adjacent compositions with which it is in contact by an axially inner interface IAI and an axially outer interface IAE, respectively.

[0119] At any point on the inner surface 19 of the radially upper portion 38, the thickness EP is measured along a straight line N1 perpendicular to the inner surface 19 at that point. The thickness EP is the distance measured along each perpendicular straight line N1 between, on the one hand, the axially outer surface SAE of the portion PC of the axially outermost reinforcing layer at the radially upper portion 38, in this example the portion PC of the axially inner portion 3611 of the carcass layer 36 at the radially upper portion 38, and, on the other hand, the smooth reference surface 44. The maximum value of the thickness measured at the radially upper portion 38 is the maximum thickness Emax. Emax is equal to or smaller than 3.0 mm and equal to or larger than 1.0 mm, preferably in the range of 1.5 mm to 2.5 mm. In this case, Emax=2.4 mm.

[0120] 3, the concave molding element 46 has a maximum depth Pmax relative to the smooth reference surface 44. Pmax is 0.8 mm or less, preferably 0.5 mm or less and 0.3 mm or more. In this case, Pmax=0.5 mm.

[0121] 4, each convex molding element 47 has a maximum height Hmax relative to the smooth reference surface 44. Hmax is equal to or less than 0.8 mm, preferably equal to or less than 0.5 mm and equal to or greater than 0.3 mm. In this case, Hmax=0.5 mm.

[0122] Therefore, Pmax, Hmax and Emax satisfy Emax^(0.4)×Pmax≦1.1 and Emax^(0.4)×Hmax≦1.1, preferably Emax^(0.4)×Pmax≦0.9 and Emax^(0.4)×Hmax≦0.9, more preferably Emax^(0.4)×Pmax≦0.8 and Emax^(0.4)×Hmax≦0.8. In this case, Emax^(0.4)×Hmax=Emax^(0.4)×Pmax=0.7. In another embodiment, Emax and / or Hmax and Pmax can be reduced such that Emax^(0.4)×Pmax≦0.6 and Emax^(0.4)×Hmax≦0.6.

[0123] Tyres according to second, third, fourth, fifth and sixth embodiments of the invention will now be described with reference to Figures 5 to 9 respectively. Elements similar to those shown in the previous figures are represented by the same reference numerals.

[0124] Unlike the tire according to the first embodiment, the carcass reinforcement 36 of the tire 10 according to the second embodiment of FIG. 5 comprises a first and a second carcass layer 36, 37 anchored to each bead 32. The first carcass layer 36 is wrapped around each circumferential reinforcing element 33 of each bead 32 such that the axially inner parts 3611, 3621 of the first carcass layer 36 are arranged axially inside the axially outer parts 3612, 3622 of the first carcass layer 36, and the axial ends 361, 362 of the first carcass layer 36 are arranged radially outside the respective circumferential reinforcing elements 33. The axial ends 371, 372 of the second carcass layer 37 are arranged radially inside the axial ends 361, 362 of the first layer and are arranged axially between the axially inner parts 3611, 3621 and the axially outer parts 3612, 3622 of the first carcass layer 36. In this second embodiment, the portion PC of the axially outermost reinforcing layer is formed by the portion PC of the second carcass layer 37 in the radially upper portion 38 .

[0125] Unlike the tire according to the second embodiment, in the tire 10 according to the third embodiment shown in Figure 6, the respective axial ends 371, 372 of the second carcass layer 37 are arranged axially inside the respective axially inner portions 3611, 3621 of the first carcass layer 36. In this third embodiment, the portion PC of the axially outermost reinforcing layer is formed by the portion PC of the first carcass layer 36 in the radial upper part 38.

[0126] Unlike the tire according to the second embodiment, in the tire 10 according to the fourth embodiment shown in Figure 7, the respective axial ends 371, 372 of the second carcass layer 37 are arranged axially outward of the respective axially outer portions 3612, 3622 of the first carcass layer 36. In this fourth embodiment, the portion PC of the axially outermost reinforcing layer is formed by the portion PC of the second carcass layer 37 in the radially upper portion 38.

[0127] Unlike the tire according to the first embodiment, in the tire 10 according to the fifth embodiment shown in Figure 8, the axial ends 361, 362 of the carcass layer 36, anchored to each bead and wound to form a turn-up, are arranged radially outside the equator E, and even more preferably axially inside the axial ends 141, 281 of the working layer 24 and the hoop layer 28 of the crown reinforcement 16. In this fifth embodiment, the portion PC of the axially outermost reinforcing layer is formed by the portion PC of the axially outermost portion 3612 of the carcass layer 36 in the radial upper portion 38.

[0128] Unlike the tire according to the first embodiment, in the tire 10 according to the sixth embodiment shown in Figure 9, in addition to the carcass reinforcement 34, the tire 10 comprises two sidewall reinforcing layers 39 arranged axially outside the carcass reinforcement 34. Each sidewall reinforcing layer 39 extends at least radially in each sidewall 30 and has a radially inner end 391 arranged radially inside the equator E and a radially outer end 392 arranged radially outside the equator E. The radially inner end 391 of each sidewall reinforcing layer 39 is arranged radially outside the respective bead 32 and is therefore not anchored to this bead.

[0129] Comparative Test

[0130] Different tyres, inflated to nominal pressure and subjected to loads significantly higher than the nominal loads specified in the ETRTO Standards Manual 2021, were run through the load / speed performance test specified in Annex VII of Regulation No. 30 of the United Nations Economic Commission for Europe (UN / ECE).

[0131] A first control tire of size HL255 / 35R20 had a thickness Emax=3.1 mm and concave and convex molding elements with a maximum depth Pmax and a maximum height Emax both equal to 0.8 mm. At the end of the test, this first tire had a crack in the radial upper part of at least one of the sidewalls.

[0132] The second tire according to the invention, size HL255 / 35R20, had a thickness Emax=2.4 mm and concave and convex molding elements with a maximum depth Pmax and a maximum height Emax both equal to 0.8 mm. At the end of the test, this tire according to the invention showed no cracks.

[0133] The present invention is not limited to the above-described embodiments. [Explanation of symbols]

[0134] 19 Tire inner surface 36 Carcass layer 38 Radial upper part of sidewall 42 Radial upper outer surface of sidewall 44 Smooth reference surface 46 Concave molding element 50 Elastomer composition 52 Outer surface of sidewall 360 carcass reinforcement elements 363 Polymer matrix E Tire Equator Emax Maximum thickness measured at the top radial position IAE axial outer interface IAI axial inner interface N1 A straight line perpendicular to the inner surface at a point on the inner surface PC Radial upper part of the outermost axial reinforcement layer Pmax Maximum depth of a concave molding element relative to a smooth reference surface SAE Axial outer surface passing through the axially outermost points of the carcass reinforcing elements SAI Axial inner surface passing through the axially innermost point of the carcass reinforcing element

Claims

1. A tire (10) for a passenger vehicle, comprising a crown (12), two beads (32), and two sidewalls (30) connecting each of said beads (32) to said crown (12), at least one of said sidewalls (30) comprising at least one reinforcing layer (36, 37, 39) comprising reinforcing elements (360) embedded in a polymer matrix (363), said or each sidewall (30) comprising: the equator (E) of said tire; - a normal (N) to the inner surface (19) passing through a circumferential boundary line (40) marking the boundary between said sidewall (30) and said crown (12); a radially upper portion (38) radially included between The radially upper portion (38) - a smooth reference surface (44); at least one shaped concave element (46) and / or at least one shaped convex element (48), which is concave or convex relative to said smooth reference surface (44); and an outer surface (42) comprising: The tire (10) It is a high load capacity type that complies with ETRTO Standard Manual 2021. a maximum thickness Emax, a maximum depth Pmax of the or each shaped concave element (46) of the radial upper portion (38) relative to the smooth reference surface (44), and / or a maximum height Hmax of the or each shaped convex element of the radial upper portion (38) relative to the smooth reference surface (44) satisfy Emax^(0.4) x Pmax≦1.1 and Emax^(0.4) x Hmax≦1.1, wherein Emax, Pmax and Hmax are expressed in mm; Emax is measured at the upper radial position (38) along a line (N1) perpendicular to the inner surface (19); an axially outer surface (SAE) passing through the axially outermost point of each of said reinforcing elements (360) of said or each part (PC) of said or each axially outermost reinforcing layer (36, 37, 39) in said radially upper part (38); - said smooth reference surface (44); is the maximum distance between A tire (10) in which Emax is 3.0 mm or less.

2. 2. The tire (10) of claim 1, wherein Emax^(0.4) x Pmax ≦ 0.9 and Emax^(0.4) x Hmax ≦ 0.9 are satisfied.

3. A tire (10) as described in claim 1, satisfying Emax^(0.4) × Pmax≦0.8 and Emax^(0.4) × Hmax≦0.

8.

4. 2. The tire (10) of claim 1, wherein the radially upper portion (38) of the or each sidewall (30) comprises an elastomer composition (50) bearing against the outer surface (52) of the radially upper portion of the sidewall (30), the elastomer composition having a modulus at 10% elongation (MA10) of 10 MPa or less.

5. 2. The tire (10) of claim 1, wherein Pmax is less than or equal to 0.8 mm.

6. 2. The tire (10) of claim 1, wherein Pmax is greater than or equal to 0.3 mm and Hmax is greater than or equal to 0.3 mm.

7. 2. The tire (10) of claim 1, wherein Emax is greater than or equal to 1.0 mm.

8. 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 0.72≦H / LI≦0.95, wherein SW, AR, and LI are defined in accordance with ETRTO Standards Manual 2021.

9. 2. A tire (10) according to claim 1, comprising a carcass reinforcement (34) including at least one carcass ply (36, 37) anchored to each of the beads (32), the crown (12) comprising a crown reinforcement (16), the carcass ply (36, 37) anchored to each of the beads (32) and extending radially within each of the sidewalls (30) and axially within the crown (12) radially inward of the crown reinforcement (16), the or each portion (PC) of the or each axially outermost reinforcing layer (36, 37) being formed by at least a part (PC) of the carcass ply (36, 37) anchored to each of the beads (32) and being axially outermost at the radially upper part (38).

10. a carcass reinforcement (34) comprising at least one carcass layer anchored to each of the beads, the crown (12) comprising a crown reinforcement (16), the carcass layer (36) anchored to each of the beads (32) extending radially within each of the sidewalls (30) and axially within the crown (12) radially inward of the crown reinforcement (16); a sidewall reinforcing layer (39) disposed axially outward of the carcass reinforcement (34); Equipped with 2. Tyre (10) according to claim 1, wherein the or each portion (PC) of the or each axially outermost reinforcing layer (39) is formed by at least a portion (PC) of the sidewall reinforcing layer (39) in the radially upper portion (38).

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