Tire with sidewall inserts

Abstract

The subject of the present invention is a tire (1) comprising at least one sidewall (3) intended to cooperate with a sidewall insert (9) through fastening means (6), the goal being to customize the design of said sidewall. According to the invention, the fastening means (6) comprising a recess (7) formed in the axially outer sidewall layer (30) comprises a protrusion (8) projecting relative to the bottom surface of the recess (71) and extending from the bottom surface of the recess (71) to the vicinity of the axially outer surface of the sidewall (31), said protrusion (8) being stepped in such a way that its first narrow portion (81) has a minimum width Lpmin and its second wide portion (82) has a maximum width Lpmax, the difference Lpmax-Lpmin being at least equal to 1 mm and at most equal to 4 mm.

Description

[Technical Field]

[0001] The present invention relates to a tire more particularly intended to equip light four-wheeled vehicles (cars, vans) or two-wheeled vehicles (motorcycles), comprising at least one sidewall with a sidewall insert intended to individualize the design of the tire sidewall. [Background technology]

[0002] A continuing concern of vehicle manufacturers and users is the individualization of tire sidewall designs using coloring means and / or using additional elements, referred to herein as inserts.

[0003] Known coloring means are, for example, white colored rubber compositions present on the sidewall of a tire, which contrast with the black color of the adjacent rubber composition. However, this technical solution has certain drawbacks. First of all, certain chemical components, such as protective ingredients, present in the rubber composition adjacent to the coloring means may migrate toward the colored rubber composition, causing it to gradually lose its color over time. In addition, deformation of the sidewall throughout the tire's service life may cause cracks in the colored rubber composition, deteriorating its appearance. Furthermore, the mechanical means used to mount a tire on its rim may also deteriorate the colored rubber composition by rubbing it against it. Finally, the production of tires with different colored sections is more complex from an industrial point of view.

[0004] Among known inserts, EP 2692542 describes a decorative ring intended to be mounted between the tire bead and the rim. However, mounting this ring is tricky due to its positioning. In addition, the presence of the ring between the tire bead and the rim can modify the mechanical behavior of the tire and, therefore, that of the vehicle. Finally, to properly install it, this ring runs the risk of requiring an adaptation of the rim's shape, which would then no longer fit the rim profile specifications for which the tire was designed.

[0005] U.S. Pat. No. 3,128,815 describes another insert in the form of a tire lining element intended to be removably engaged with the sidewall. This lining element may be fixed to the sidewall by various means, such as engagement of its ends with the sidewall or attachment of its ends by means of fastening means raised or recessed relative to the sidewall. Furthermore, the described lining element covers a significant portion of the sidewall, typically at least one-third of the sidewall's surface area, and is more specifically positioned on the radially inner segment of the sidewall between the axially outermost point of the sidewall and the rim flange. However, because this lining element is positioned in a zone of high flexure in the tire, it is prone to deformation and separation from the sidewall when the tire is running.

[0006] JP 11-151918 A also describes a removable collar insert intended to be fixed to the tire sidewall near the tread in the radially outer segment of the sidewall by means of mounting means recessed relative to the surface of the sidewall. However, such mounting means do not allow the insert to be easily mounted on the tire when the tire is mounted on its rim and inflated, because the shape of the insert there, depending on the inflation pressure or the width of the rim, may be insufficient compared to the shape of the recess of the mounting means. In addition, when the tire is running, the locking of the insert in the sidewall may be modified, for example, under strong transverse acceleration, with the risk of the insert being ejected. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent No. 2692542 [Patent Document 2] U.S. Patent No. 3,128,815 [Patent Document 3] Japanese Patent Application Publication No. 11-151918 Summary of the Invention [Problem to be solved by the invention]

[0008] The objective that the inventor has set himself is to propose a tire that can be equipped with at least one sidewall insert that has improved mounting on the sidewall and attachment thereto. [Means for solving the problem]

[0009] This object is achieved by a tire for light vehicles, intended to be mounted on a rim and which can be equipped with at least one sidewall insert, said tire having a nominal cross section of height H and two side walls each intended to connect the crown to two beads and to come into contact with the rim; at least one side wall provided with fastening means intended to interact with at least one side wall insert; Equipped with the anchoring means extends at least partially circumferentially around the tire, and the anchoring means comprises a recess formed in the axially outer sidewall layer comprising at least one rubber material and extending axially from the axially outer sidewall surface towards the inside of the sidewall; the recess is bounded axially inwardly by a recess bottom surface and radially by two recess walls; the recess has a depth Pc, being the maximum distance measured perpendicularly between the axially outer sidewall surface and the bottom of the recess, equal to at least 2 mm in any meridian plane containing the tire's axis of rotation, and a width Lc, measured at the axially outer sidewall surface between the two recess walls, equal to at most 15% of the tire's nominal section height H, the fastening means comprises a protrusion that rises relative to the bottom surface of the recess and extends from the bottom surface of the recess to the vicinity of the axially outer side wall surface; the protrusion is constituted by a stepped arrangement of a first narrow portion extending axially outward from the bottom of the recess and having a minimum width equal to the minimum protrusion width Lpmin, and a second wide portion extending axially outward from the first narrow portion and having a maximum width equal to the maximum protrusion width Lpmax, such that in any meridian plane the difference Lpmax-Lpmin is at least equal to 1 mm and at most equal to 4 mm.

[0010] A principle of the present invention is to have a fastening means for the sidewall insert, the fastening means comprising a circumferential recess formed in the axially outer sidewall layer and a protrusion formed in the recess.

[0011] The recesses may be circumferentially continuous or circumferentially discontinuous, i.e. formed in separate circumferential portions.

[0012] The axially outer sidewall layer in which the recess is formed extends axially from its axially outer sidewall surface in contact with the atmosphere to the axially outermost reinforcing layer formed of a reinforcing material, most often a fabric. More specifically, the axially outer sidewall layer is in axially inner contact with a rubber compound, usually called a coating compound, which coats the reinforcing material of the axially outermost reinforcing layer.

[0013] The recesses make it possible to secure the sidewalls by locking the edges of the sidewall insert between them, which in turn helps to keep the sidewall insert in place, which would otherwise be prone to being expelled when the tire is running.

[0014] The recesses also allow the sidewall insert to engage the thickness of the sidewall without creating a significant protrusion relative to the axially outer sidewall surface, and therefore without disrupting the airflow near the sidewall in this zone. As a result, the aerodynamic resistance of the tire is not increased, and correspondingly, the rolling resistance and therefore fuel consumption of the tire are not increased.

[0015] According to the invention, the depth Pc of the recess is at least equal to 2 mm.

[0016] If the depth Pc is less than 2 mm, the fastening means do not ensure sufficient attachment of the sidewall insert to enable the tire to withstand the various mechanical stresses applied to it in the course of its use throughout its service life.

[0017] Also according to the invention, the width Lc of the recess is equal to at most 15% of the nominal section height H of the tire.

[0018] The recess width Lc must remain limited because the greater it is, the greater the deflection of the zone of the sidewall insert during use, which causes significant deformation of the sidewall insert and potential fatigue problems. The deformation at the recess specifically increases with the recess width Lc, the width of which can be expressed as a percentage of the nominal section height H of the tire or as an absolute value. The nominal section height H is defined by the usual standards relating to tires, such as, for example, the "European Tyre and Rim Technical Organisation" or "ETRTO" standard.

[0019] The protrusion formed in the recess from the bottom surface of the recess is intended to contact the axial inner surface of the sidewall insert and, due to its specific shape, allows the sidewall insert to be fixed. The protrusion is configured in a stepped arrangement, in any meridian plane, of a first narrow portion extending axially outward from the bottom surface of the recess and having a minimum width equal to the minimum protrusion width Lpmin, and a second wide portion extending axially outward from the first narrow portion and having a maximum width equal to the maximum protrusion width Lpmax. Such a protrusion is essentially mushroom-shaped, with its stem being the first narrow portion and its cap being the second wide portion. This protrusion configuration allows the sidewall insert to be substantially fastened on the protrusion and ensures that it remains in place under the mechanical bending and centrifugal stresses applied to the tire when it is running.

[0020] Advantageously, the depth Pc of the recess is: at least Equals 3mm.

[0021] More advantageously, the depth Pc of the recess is at most equal to 7 mm, preferably at most equal to 5 mm.

[0022] If the depth Pc is greater than 7 mm, the thickness of the layer of rubber material axially inside the recess bottom is not sufficient to ensure mechanical disconnection between the sidewall insert intended to be engaged in this recess and the axially outermost reinforcing layer. This leads to stress concentrations at the recess bottom that are prone to cracking and reduced durability of the sidewall. Furthermore, in terms of manufacturing, a recess with a limited depth ensures the presence of a thickness of the layer of rubber material axially inside the recess bottom, despite the presence of significant movement of material present in this zone during the stages of assembling and subsequently finishing the tire. In other words, a recess depth that is not excessively high makes it possible to guarantee manufacturing tolerances.

[0023] With the axially outer sidewall layer having a width W at the fastening means, the difference between the thickness W of the axially outer sidewall layer and the depth Pc of the recess is at least equal to 1 mm, preferably at least equal to 2 mm.

[0024] The thickness W is measured between the axially outer sidewall surface and the axially outer fibers of the reinforcement of the axially outermost reinforcing layer, and this thickness therefore takes into account the actual axially outer sidewall layer and the axially outer coating layer of the axially outermost reinforcing layer. The difference between the thickness W of the axially outer sidewall layer and the depth Pc of the recess, in turn, determines the thickness of the layer of rubber material provided between the bottom surface of the recess and the axially outermost reinforcing layer.

[0025] The thickness of 1 mm is the minimum thickness of the layer of rubber material that ensures a mechanical disconnection between the sidewall insert intended to be engaged in said recess at its interface with the axially outer sidewall layer and the axially inner reinforcement of the reinforcement, thereby avoiding stress concentrations at the bottom of the recess that are prone to cracking and a decrease in the durability of the sidewall.

[0026] Advantageously, the width Lc of the recess is equal to at most 10% of the nominal section height H of the tire.

[0027] Also advantageously, the width Lc of the recess is at most equal to 20 mm, preferably at most equal to 12 mm.

[0028] Preferably, the recesses are formed in an axially outer sidewall layer made of a single rubber material.

[0029] As a result, no recesses are formed in the composite layer, which is made up of overlapping materials and is therefore potentially susceptible to mechanical strength problems at the interface between the materials.

[0030] Advantageously, a straight line lying in any meridian plane and passing through each of the two intersection points of each concave wall with the axially outer side wall surface forms with the radial direction an angle at most equal to 25°, preferably at most equal to 15°.

[0031] When the angle A is greater than 25°, the axially outer sidewall surface becomes excessively inclined relative to the radial direction, generally in the zone of the fastening means close to the tire bead, so that the lateral wall of the recess does not make it possible to retain the sidewall insert, which will deform under the action of centrifugal forces.

[0032] Preferably, the protrusion has a height Hp in any meridional plane at least equal to 2 mm less than the depth Pc of the recess.

[0033] The minimum height value Hp, equal to 2 mm less than the recess depth Pc, allows the sidewall insert to be positioned on the protrusion with sufficient anchoring height while still not protruding beyond the axially outer sidewall surface or only protruding very slightly beyond it. This configuration thus ensures effective anchoring of the sidewall insert while still protecting it from potential abrasion of the sidewall against the curb. Furthermore, the limited engagement of the sidewall insert within the thickness of the sidewall allows it to be viewed as a design measure.

[0034] Also preferably, the protrusion has a height Hp in any meridional plane that is at least equal to 2 mm greater than the depth Pc of the recess.

[0035] The maximum height value Hp, equal to 2 mm greater than the recess depth Pc, makes it possible to avoid the insert being raised relative to the axially outer sidewall surface. This configuration, in other words, makes it possible not to disturb the air flow in the vicinity of the sidewall in this zone. As a result, the aerodynamic resistance of the tire does not increase. Correspondingly, the rolling resistance of the tire and therefore its fuel consumption also do not increase. Furthermore, the susceptibility of the sidewall to potential abrasion against curbs remains limited.

[0036] If the side wall comprises a protective ridge on its axially outer side wall surface and near the radially outer side of the bead, and the fastening means has a circumferential mean line, the circumferential mean line of the fastening means is advantageously positioned in any meridian plane radially outside the edge corner of the protective ridge at a radial distance d1 at least equal to 4 mm.

[0037] The protective ridge is positioned on the axially outer sidewall surface and radially outwardly adjacent the bead. Positioning radially outwardly adjacent the bead means that the radially innermost point of the protective ridge is positioned at a radial distance of at least 4 mm radially outwardly of the rim flange on which the tire is intended to be mounted. Furthermore, the edge corners of the protective ridge are the apexes of the substantially triangular cross sections of the protective ridge that are not positioned on the axially outer sidewall surface.

[0038] Since the function of the protective ridge is to protect the flange of the rim on which the tire is intended to be mounted, it is the part of the tire that is most likely to rub against external elements such as curbs and stones, and also the part that is most likely to come into contact with the ground when the tire is removed. Consequently, the sidewall insert and therefore the corresponding fastening means must be far enough away from the protective ridge to avoid being damaged. Furthermore, fastening means closer to the protective ridge make it more visible.

[0039] Also advantageously, the circumferential mean line of the fastening means is positioned in any meridian plane radially inward of an axial straight line passing through the midpoint H / 2 of the nominal section height of the tyre at a radial distance d2 equal to at least 10% of the nominal section height H of the tyre.

[0040] If for certain tires with a small nominal section height H and therefore a small sidewall height the protective ridge is at the axially outermost part of the tire, for other tires the axially outermost point of the tire is positioned on an axial straight line passing through the midpoint H / 2 of the nominal section height of the tire. For these tires, in order to avoid degradation of the sidewall insert, especially when the sidewall is worn against a curb, the circumferential mean line of the corresponding fastening means is advantageously positioned radially radially inward of the axial straight line passing through the midpoint H / 2 of the nominal section height of the tire, at a radial distance d2 equal to at least 10% of the nominal section height H of the tire. Typically, the radial distance d2 is equal to at least 2 mm, preferably at least 8 mm.

[0041] The present invention also relates to a sidewall insert intended to be mounted on a tire sidewall.

[0042] The sidewall insert is intended to interact with a fastening means according to any of the above-mentioned embodiments by engaging in a recess in the fastening means and by clipping onto a protrusion in the fastening means.

[0043] In the case of fastening means comprising protrusions with an outer meridian profile, the side wall insert preferably has an inner meridian profile parallel to the outer meridian profile of the protrusions, such that the inner meridian profile of the side wall insert has a minimum insert width Limin at a minimum protrusion width Lpmin and a maximum insert width Limax at a maximum protrusion width Lpmax, in other words the side wall insert has a mushroom shape that constitutes a female part with which the male mushroom shape of the protrusions interlocks, which makes it possible to guarantee good fastening.

[0044] According to a first variant of the preferred embodiment of the sidewall insert, the difference Lpmax-Limin between the maximum protrusion width Lpmax and the minimum insert width Limin is at least equal to 1.5 mm.

[0045] According to a second variant of the preferred embodiment of the sidewall insert, the difference Lpmax-Limin between the maximum protrusion width Lpmax and the minimum insert width Limin is at most 2 * E, which is the distance between a line passing through the cross section of the minimum insert width Limin and the axially outer bearing surface of the insert that bears against the protrusion.

[0046] Specifically, to allow for effective fixation, i.e., having sufficient locking of the sidewall insert on the protrusion, the difference Lpmax-Limin between the maximum protrusion width Lpmax and the minimum insert width Limin should be in the range of values ​​[1.5 mm; 2 * E]. Below the lower limit, there is a risk that it will be difficult to mount the insert on the protrusion. Above the upper limit, there is a risk that the effectiveness of the fixation will be reduced.

[0047] This spacing defines a range of optimum locking between the sidewall insert and the protrusion, both at the maximum cross section corresponding to the respective maximum widths Lpmax and Limax, and at the minimum cross section corresponding to the respective minimum widths Lpmin and Limin. At the maximum cross section, the locking is defined by Lpmax - Limax. At the minimum cross section, the locking is defined by Lpmin - Limin.

[0048] The sidewall insert has a circumferential mean line with a mean diameter D2 that is at most equal to the mean diameter D1 of the circumferential mean line of the fastening means before the sidewall insert is fastened to the tire. In these conditions, the sidewall insert is fastened to the fastening means under prestress, which contributes to effectively holding the sidewall insert in place within the sidewall with a low risk of being released when the tire is running.

[0049] According to certain embodiments, the sidewall insert may have a variable width near the axially outer sidewall surface, which entails a variable width recess in the fastening means and therefore a fastening means that does not exhibit rotational symmetry about the axis of rotation of the tire.

[0050] According to a preferred embodiment, the sidewall insert comprises at least one polymeric material such as a rubber material, silicone, or a thermoplastic material, for example polyurethane.

[0051] The material or materials from which the sidewall insert is made must be sufficiently deformable so as not to create excessive stresses at the interface between the sidewall insert and the fastening means that would tend to induce cracks and fatigue failure in the tire sidewall. Polymeric materials such as rubber materials, silicones, or thermoplastic materials, e.g., polyurethanes, are believed to satisfy this requirement, as this list is not exhaustive.

[0052] If the sidewall insert is made of a material having a tensile modulus M2 at 10% elongation and is intended to interact with fastening means made of a rubber material having a tensile modulus M1 at 10% elongation, M2 is advantageously at least 0.4 * Equal to M1. The sidewall insert must be rigid enough to allow it to be installed on the sidewall.

[0053] If the sidewall insert is made of a material having a tensile modulus M2 at 10% elongation and is intended to interact with fastening means made of a rubber material having a tensile modulus M1 at 10% elongation, M2 may also advantageously be at most 5 * Equal to M1. The sidewall insert must not be too hard so as to not create excessive stresses in the tire sidewall that would make the sidewall prone to damage when subjected to bending stresses, and to reduce the risk of the sidewall insert being ejected by centrifugal forces when the tire is in motion.

[0054] The sidewall insert preferably has a different color and / or texture than that of the sidewall that comprises the fastening means. Since an object of the present invention is to individualize tire sidewall design, the sidewall insert preferably has a different color and / or texture than the sidewall.

[0055] Preferably, the colored sidewall inserts may have one or more differentiated colors relative to the normally black sidewall. Also preferably, the sidewall inserts are monochromatic to simplify their manufacture.

[0056] According to certain embodiment variations, the sidewall inserts are covered with graphics or, for example, a velvet-type texture to further differentiate the sidewalls.

[0057] Finally, the invention relates to an assembly made of a tire according to any one of the tire embodiments described above and at least one sidewall insert according to any one of the sidewall insert embodiments described above.

[0058] Features of the present invention are illustrated in schematic diagrams 1 through 5, which are not drawn to scale. [Brief explanation of the drawings]

[0059] [Figure 1] 1 shows a meridian semi-section through a tire according to the invention mounted on its rim; [Figure 2] 1 is a meridional section through a fastening means according to the invention; FIG. [Figure 3] 1 shows a meridian semi-section through a tire according to the invention mounted on its rim and equipped with sidewall inserts; FIG. [Figure 4] 1 is a meridional section through a fastening means according to the invention in combination with a side wall insert; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0060] 1 is a meridional semi-section through a tire 1 according to the invention mounted on its rim 2. The tire 1 for light vehicles is mounted on the rim 2 and can be equipped with at least one sidewall insert 9 (not shown). The tire 1 has a nominal section of height H within the meaning of the ETRTO (European Tire and Rim Technical Organisation) standard and comprises two sidewalls 3 each connecting a crown 4 to two beads 5 each intended to come into contact with the rim 2. The sidewall 3 shown comprises fastening means 6 intended to interact with the sidewall insert 9 (not shown). The fastening means 6 extend circumferentially in the circumferential direction XX' of the tire and are formed in an axially outer sidewall layer 30 comprising at least one rubber material and comprise a recess 7 extending from the axially outer sidewall surface 31 towards the axial inside of the sidewall 3. According to the invention, the fastening means 6 comprises a protrusion 8 raised relative to the recess bottom surface and extending from the recess bottom surface to the vicinity of the axially outer side wall surface 31, the protrusion 8 being constituted by a stepped arrangement in either meridian plane YZ of a first narrow portion extending axially outward from the recess bottom surface and having a minimum width equal to the minimum protrusion width Lpmin (not referenced) and a second wide portion extending axially outward from the first narrow portion and having a maximum width equal to the maximum protrusion width Lpmax. In the particular embodiment shown in Figure 1, the side wall 3 comprises a protective ridge 32 on its axially outer side wall surface 31 and near the radially outer side of the bead 5, with the edge corner 321 of the protective ridge 32 being the apex of a substantially triangular cross section of the protective ridge that is not located on the axially outer side wall surface 31. In the case of the fastening means 6 having a circumferential mean line 61, the circumferential mean line 61 of the fastening means 6 is positioned in the meridian plane YZ at a radial distance d1 equal to at least 4 mm radially outside the edge corners 321 of the protective ridge 32. Furthermore, the circumferential mean line 61 of the fastening means 6 is positioned in the meridian plane YZ at a radial distance d2 equal to at least 10% of the nominal section height H of the tire 1 radially inside an axial straight line D passing through the midpoint H / 2 of the nominal section height H of the tire 1.

[0061] 2 is a meridional section through the fastening means 6 according to the invention. This is a detail of FIG. 1. The fastening means 6 comprises a recess 7 and a protrusion 8. The recess 7 is delimited axially inwards by a recess bottom 71 and radially by two recess walls 72. The recess 7 has a depth Pc, which is the maximum distance measured perpendicularly between the axially outer sidewall surface 31 and the recess bottom 71 in a meridian plane YZ containing the tire's axis of rotation YY', and a width Lc, measured between the two recess walls 72 at the axially outer sidewall surface 31. The depth Pc of the recess 7 is at least equal to 2 mm and at most equal to 7 mm. The width Lc of the recess 7 is at most equal to 15%, preferably at most 10%, of the nominal section height H of the tire 1. If the axially outer sidewall layer 30 has a thickness W at the fastening means 6, the difference between the thickness W of the axially outer sidewall layer 30 and the depth Pc of the recess 7 is at least equal to 1 mm. Furthermore, a straight line T that lies in the meridian plane YZ and passes through two intersection points 721, 722 of each recessed wall 72 with the axially outer side wall surface 31 forms an angle A with the radial direction ZZ' that is at most equal to 25°. Finally, in any meridian plane YZ, the protrusion 8 is constituted by a stepped arrangement of a first narrow portion 81 that extends axially outward from the recess bottom surface 71 and has a minimum width equal to the minimum protrusion width Lpmin, and a second wide portion 82 that extends axially outward from the first narrow portion 81 and has a maximum width equal to the maximum protrusion width Lpmax.

[0062] 3 is a view of a meridian semi-section through a tire according to the invention mounted on a rim and equipped with a sidewall insert 9. This combines the tire of FIG.

[0063] 4 is a meridional section through the fastening means according to the invention shown in FIG. 2 in combination with a side wall insert. This is a detail of FIG. 4. The fastening means 6 comprising a protrusion has an outer meridional profile P. The side wall insert 9 has an inner meridional profile P' parallel to the outer meridional profile P of the protrusion 8. The inner meridional profile P' of the side wall insert 9 has a minimum insert width Limin at a minimum protrusion width Lpmin and a maximum insert width Limax at a maximum protrusion width Lpmax. Furthermore, with the preferred variant shown, the difference Lpmax-Limin between the maximum protrusion width Lpmax and the minimum insert width Limin is at least equal to 1.5 mm and at most 2. * E, which is the distance between the straight line G passing through the cross section of the minimum insert width Limin and the axially outer bearing surface 91 of the insert 9 bearing against the protrusion 8.

[0064] The inventor has examined the invention in more detail on a tire of size 245 / 45 R 18 100 W XL, intended to be inflated to a recommended pressure equal to 2.9 bar and to carry a recommended load equal to 800 kg.

[0065] The properties of the examples tested by the inventors are presented in Table 1 below.

[0066] [Table 1]

[0067] The inventors have been able to appreciate easier installation and more efficient mounting for sidewall inserts mounted in the sidewalls of tires according to the present invention. [Explanation of symbols]

[0068] 1 tire 2 rims 6 Fixing means 9 Sidewall Inserts H Nominal section height of tire

Claims

1. intended to be mounted on a rim (2) and which may be equipped with at least one sidewall insert (9), and which has a nominal cross section of height H; two side walls (3) respectively connecting the crown (4) to two beads (5) each intended to come into contact with said rim (2); at least one side wall (3) provided with fastening means (6) intended to interact with at least one side wall insert (9); Equipped with the fastening means (6) extending circumferentially in the circumferential direction (XX') of the tire and comprising recesses (7) formed in the axially outer sidewall layer (30) comprising at least one rubber material and extending axially from the axially outer sidewall surface (31) towards the inside of the sidewall (3), The recess (7) is bounded axially inward by a recess bottom surface (71) and radially by two recess walls (72), said recess (7) having a depth Pc, which is the maximum distance measured perpendicularly between said axially outer side wall surface (31) and said recess bottom surface (71), equal to at least 2 mm in any meridian plane (YZ) containing the tire's rotation axis (YY'), and a width Lc, measured on said axially outer side wall surface (31) between said two recess walls (72), equal to at most 15% of said nominal section height H of the tire (1), A tire (1) for a light vehicle, comprising: The fixing means (6) includes a protrusion (8) that protrudes from the recess bottom surface (71) and extends from the recess bottom surface (71) to the vicinity of the axially outer side wall surface (31), The protrusion (8) is constituted by a stepped arrangement of a first narrow portion (81) extending axially outward from the recess bottom surface (71) and having a minimum width equal to the minimum protrusion width Lpmin, and a second wide portion (82) extending axially outward from the first narrow portion (81) and having a maximum width equal to the maximum protrusion width Lpmax, such that the difference Lpmax-Lpmin is at least equal to 1 mm and at most equal to 4 mm in any meridian plane (YZ). A tire (1) characterized in that

2. Tyre (1) according to claim 1, characterized in that the depth Pc of the recess (7) is at least equal to 3 mm.

3. Tyre (1) according to claim 1 or 2, characterized in that the depth Pc of the recess (7) is at most equal to 7 mm.

4. said axially outer sidewall layer (30) having a thickness W at said fastening means (6); the difference between the thickness W of the axially outer sidewall layer (30) and the depth Pc of the recess (7) is at least equal to 1 mm; Tyre (1) according to any one of claims 1 to 3.

5. Tyre (1) according to any one of claims 1 to 4, characterized in that the width Lc of the recess (7) is equal to at most 10% of the nominal section height H of the tyre (1).

6. Tyre (1) according to any one of claims 1 to 4, characterized in that the width Lc of the recess (7) is at most equal to 20 mm.

7. Tyre (1) according to any one of the preceding claims, characterized in that the recess (7) is formed in an axially outer sidewall layer (30) made of a single rubber material.

8. 8. Tyre (1) according to any one of claims 1 to 7, characterized in that a straight line (T) lying in any meridian plane (YZ) and passing through two intersection points (721, 722) of each recessed wall (72) respectively with said axially outer side wall surface (31) forms with the radial direction (ZZ') an angle (A) equal to at most 25°.

9. 9. Tyre (1) according to any one of claims 1 to 8, characterized in that the protrusions (8) have a height Hp, in any meridian plane (YZ), at least equal to 2 mm less than the depth Pc of the recesses (7).

10. the side wall (3) comprises, on its axially outer side wall surface (31) and in the radially outer vicinity of the bead (5), a protective ridge (32) having an edge corner (321), the fastening means (6) having a circumferential mean line (61); the circumferential mean line (61) of the fastening means (6) is positioned in any meridian plane (YZ) radially outside the edge corners (321) of the protective ridge (32) at a radial distance d1 equal to at least 4 mm; Tyre (1) according to any one of claims 1 to 9.

11. 11. Tyre (1) according to claim 10, characterized in that the circumferential mean line (61) of the fastening means (6) is positioned in any meridian plane (YZ) radially inside an axial straight line (D) passing through the midpoint H / 2 of the nominal section height of the tyre (1) at a radial distance d2 equal to at least 10% of the nominal section height H of the tyre (1).

12. A sidewall insert (9) intended to interact with the fastening means (6) of a tire (1) according to any one of claims 1 to 11 by engaging in said recesses (7) of said fastening means (6) and by clipping onto said protrusions (8) of said fastening means (6).

13. 13. The sidewall insert (9) according to claim 12, characterized in that the fastening means (6) comprises a protrusion (8) with an outer meridional profile (P), and the sidewall insert (9) has an inner meridional profile (P') parallel to the outer meridional profile (P) of the protrusion (8), so that the inner meridional profile (P') of the sidewall insert (9) has a minimum insert width Limin at the minimum protrusion width Lpmin and a maximum insert width Limax at the maximum protrusion width Lpmax.

14. Sidewall insert (9) according to claim 12 or 13, characterized in that the difference Lpmax-Limin between the maximum protrusion width Lpmax and the minimum insert width Limin is at least equal to 1.5 mm.

15. The difference Lpmax-Limin between the maximum protrusion width Lpmax and the minimum insert width Limin is at most 2 * 15. A sidewall insert (9) according to any one of claims 12 to 14, characterized in that it is equal to E, E being the distance between a straight line (G) passing through a cross section of the minimum insert width Limin and an axially outer bearing surface (91) of the insert (9) bearing against said protrusion (8).

16. 16. A sidewall insert (9) according to any one of claims 12 to 15, characterized in that before the sidewall insert is fastened to the tire (1), it has a circumferential mean line with a mean diameter D2 at most equal to the mean diameter D1 of the circumferential mean line of the fastening means (6).

17. Sidewall insert (9) according to any one of claims 12 to 16, characterized in that it comprises at least one polymer material.

18. made of a material having a tensile modulus M2 at 10% elongation and intended to interact with fastening means (6) made of a rubber material having a tensile modulus M1 at 10% elongation, M2 is at least 0.4 * is equal to M1, Sidewall insert (9) according to any one of claims 12 to 17.

19. made of a material having a tensile modulus M2 at 10% elongation and intended to interact with fastening means (6) made of a rubber material having a tensile modulus M1 at 10% elongation, M2 is a maximum of 5 * is equal to M1, Sidewall insert (9) according to any one of claims 12 to 18.

20. 20. Side wall insert (9) according to any one of claims 12 to 19, characterized in that it has a different colour and / or texture to that of the side wall (3) comprising the fastening means (6).

21. An assembly (10) consisting of a tire (1) according to any one of claims 1 to 11 and at least one sidewall insert (9) according to any one of claims 12 to 20.

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