Pneumatic

Abstract

The invention relates to a tire comprising two sidewalls (106) connecting a crown to two beads respectively. At least one of the two sidewalls comprises an outer layer (120) which carries an external surface (124) in contact with atmospheric air, which extends radially between the crown and the corresponding bead, which extends axially from the external surface to an internal structure (122) of the sidewall, and which is made of a first elastomeric composition comprising a staining agent.The sidewall also includes an anchoring element (130), which consists of a second elastomeric composition that inhibits the migration of the staining agent. This element is integrated into the outer layer, forming with it a vulcanized bonding interface (132) extending from the outer surface into the thickness of the outer layer. This interface is adapted to mechanically retain a sidewall insert, attached externally to the tire, so as to keep the sidewall insert away from the outer layer. (See Figure 2 for abbreviations.)

Description

Title of the invention: Pneumatics

[0001] The present invention relates to a pneumatic tire.

[0002] The invention relates in particular, but not exclusively, to tires for light vehicles, especially passenger vehicles, including four-wheeled and two-wheeled vehicles. A tire is defined as a band designed to form a cavity by cooperating with a mounting support, for example, a rim, this cavity being capable of being pressurized to a pressure higher than atmospheric pressure. The tire has a substantially toroidal shape of revolution around an axis of revolution of the tire, which coincides with an axis of rotation around which the tire can be driven to rotate in order to roll on the ground. This axis of revolution defines three directions, namely an axial direction, a circumferential direction, and a radial direction, conventionally used by those skilled in the art to describe the tire according to the following conventions:

[0003] - by axial direction, we mean the direction substantially parallel to the axis of tire revolution, that is to say the axis of rotation of the tire;

[0004] - by radial direction, we mean the direction along a radius of the tire, that is to say any direction intersecting the axis of rotation of the tire and substantially perpendicular to this axis;

[0005] - by circumferential direction, we mean the direction which is substantially perpendicular to both the axial direction and a radius of the tire; in other words, the circumferential direction is tangent to a circle whose center is on the axis of rotation of the tire; the circumferential direction is thus tangent to a rolling surface of the tire;

[0006] - by median plane, we mean the plane perpendicular to the axis of rotation of the pneumatic, which passes through the axial middle of the tire's rolling surface;

[0007] - by meridian plane, we mean a plane containing the axis of rotation of the tire, the the meridian plane being thus perpendicular to the circumferential direction;

[0008] - by radially internal, respectively radially external, we mean more close to the tire's axis of rotation, respectively further from the tire's axis of rotation; and

[0009] - by axially internal, respectively axially external, we mean more close to the median plane of the tire, respectively further from the median plane of the tire.

[0010] Typically, the tire comprises a vertex extended radially inwards on each side of the tire's median plane by first and second sidewalls, and then by first and second bead sections intended to come into contact with a mounting surface, such as a wheel rim. The crown, the first and second sidewalls, and the first and second bead sections define a toroidal inflation cavity for the tire. Here, a bead section is understood to be the radial portion of the tire designed to allow the tire to be attached to the mounting surface, specifically the rim. Thus, each bead section is specifically designed to be in contact with a rim hook, enabling it to be attached. The bead section is therefore delimited radially internally by the inner radial end of the tire and radially externally by an axial line passing through the outermost radial point in contact with a standard rim as defined by the European Tyre and Rim Technical Organisation (ETRTO) standard, 2020. Furthermore, a sidewall section is understood to be the radial portion of the tire connecting the bead section to the crown.The sidewall is radially delimited externally by a straight line perpendicular to the outer surface of the tire passing through the point where the angle between the tangent to the outer surface of the tire and a line parallel to the axial direction passing through that point is equal to 30°. When there are several points on a meridian plane where this angle is equal to 30° in absolute value, the radially outermost point is retained. The sidewall is radially delimited internally by an axial line passing through the radially outermost point in contact with a standard rim as defined by the European Tyre and Rim Technical Organisation (ETRTO) standard, 2020.

[0011] The invention relates more specifically to tires in which at least one or both of the sidewalls are designed to receive and mechanically retain a sidewall insert, which is attached to the corresponding sidewall in order to personalize the aesthetic appearance of the corresponding sidewall and, thereby, of the tire.

[0012] WO2022 / 069831 and WO2022 / 069832, which describe such a pneumatic tire, disclose Each insert is designed to create a recess directly within the thickness of the outer layer of the sidewall. The sidewall insert is anchored into this recess by mechanically engaging, typically through clipping, with a raised protrusion at the bottom of the recess, which is molded from the outer layer of the sidewall. Once clipped to the protrusion, the sidewall insert aesthetically enhances the tire sidewall by covering only a portion of the outer layer. This allows for customization with color(s) and / or pattern(s) that contrast with the remaining outer layer, which is typically black and generally uniform except for peripheral marking areas.

[0013] It has been observed that, as soon as the side insert is clipped in, it tends to quickly become stained throughout, with the appearance of dark areas that seem to originate within the thickness of the side insert and spread to the surface, whether evenly or unevenly. These stains, which cannot be removed by simply cleaning the surface of the side insert, significantly degrade the desired aesthetic effect.

[0014] The aim of the present invention is to remedy this degraded situation, by proposing a solution which, without calling into question the use of a clipped side insert, guarantees a lasting aesthetic effect in a simple and effective manner.

[0015] For this purpose, the invention relates to a tire comprising two sidewalls connecting a top to respectively two ridges adapted to hook the tire onto a mounting support.At least one of the two sidewalls comprising (i) an outer layer, which carries an external surface in contact with atmospheric air, extends radially between the apex and the corresponding bead, extends axially from the external surface to an internal structure of the sidewall, and is made of a first elastomeric composition which includes at least one staining agent, and (ii) at least one anchoring member, which is made of a second elastomeric composition, which is different from the first elastomeric composition and which inhibits the migration of said at least one staining agent, integrated into the outer layer, by forming with it a vulcanized bonding interface which extends from the external surface into the thickness of the outer layer, and adapted to mechanically retain at least one sidewall insert, attached externally to the tire, so as to keep said at least one sidewall insert away from the outer layer.

[0016] One of the ideas underlying the invention is to anchor one or more sidewall inserts not directly into the outer layer of the sidewall to be covered, but into a dedicated anchoring element which, while being integrated, i.e., co-vulcanized, with the outer layer of the sidewall, is designed to prevent the sidewall insert(s) attached to the tire from undergoing the staining phenomenon mentioned above. Indeed, the inventors have established that the stains mentioned above, which tend to degrade the appearance of the sidewall insert(s) used on existing tires, originate from staining agents contained in the elastomeric composition of the outer layer of the sidewall. These staining agents include, in particular, antioxidants and / or their oxidation product(s), especially 6PPD and / or its oxidation product, namely 6PPDQ.Regardless of the chemical nature of these staining agents, their presence in the outer layer of the sidewall is justified by the effects they provide, for example, the crack-resistant effect of 6PPD. Therefore, omitting these staining agents from the outer layer of the sidewall to preserve the aesthetic effect of added sidewall inserts is undesirable, unless a complete reformulation of the elastomeric composition of the outer sidewall layer is considered. The invention cleverly relies on an anchoring element, the structural geometry of which allows it to receive and fix [the element]. Mechanically, one or more sidewall inserts are attached, preventing the insert(s) from contacting the outer layer of the sidewall. The elastomeric composition of these inserts, different from that of the outer layer, allows the anchoring element to be locally integrated within the thickness of the outer sidewall layer, being co-vulcanized with it. Furthermore, it prevents staining agents contained in the outer layer of the sidewall from migrating through the anchoring element to reach the sidewall insert(s). In doing so, the inventors departed from standard industry practices by placing this anchoring element in a region of the tire—namely, the outer part of the sidewalls—where a single elastomeric composition is typically used, prioritizing tear resistance and rolling resistance.Thus, the sidewall insert(s) attached to the tire according to the invention, which are mechanically held in place by the anchoring device(s), are protected by the latter from the staining agents present in the outer layer of the sidewall. This prevents the appearance of stains such as those mentioned above on the sidewall inserts and thereby preserves the aesthetic effect provided by this or these sidewall insert(s). It should be noted that this result of the invention is obtained regardless of the constituent material and / or dimensions of the sidewall insert(s), which underlines that the inventors' approach also departed from a simple attempt to manipulate the nature and / or thickness of the sidewall inserts to limit the extent or rate of staining on these inserts.

[0017] In practice, the invention is not limited to a specific elastomeric composition for the anchoring element(s), provided that this elastomeric composition ensures both the prevention of staining agent migration through the anchoring element and the co-vulcanization of the anchoring element into the thickness of the outer layer of the sidewall. It should be noted that "elastomeric composition" means a composition comprising, predominantly by weight, one or more elastomers; this composition may also include fillers and other components commonly used in the field of tire compounds. In this text, the terms "elastomer" and "rubber" are commonly used interchangeably.

[0018] Thus, as detailed below, according to a first possible characterization of the elastomeric composition constituting the anchoring element(s), the elastomer(s) of this elastomeric composition comprise predominantly by weight one or more butyl rubbers, which contribute to forming a barrier against the migration of the aforementioned staining agents. Preferably, this elastomeric composition also comprises one or more natural rubbers, which contribute to increasing the resistance of the vulcanized bonding interface between the anchoring element and the outer layer of the flank. As further detailed and quantified below, according to a second possible characterization of the elastomeric composition constituting the anchoring element(s), this elastomeric composition exhibits limited oxygen permeability, which helps to block the migration of the aforementioned staining agents. One or more other characterizations of the elastomeric composition constituting the anchoring element(s) are conceivable.

[0019] Furthermore, regardless of the specificities of the elastomeric composition constituting the anchoring element or each anchoring element, advantageous aspects of the anchoring element or each anchoring element will be detailed later, in particular in relation to (i) their positioning with respect to the rest of the tire according to the invention, in particular to limit in service the mechanical stresses of the vulcanized bonding interface between the anchoring element and the outer layer of the sidewall, (ii) their hollow structural geometry, in particular to reconcile resistant anchoring of the added sidewall insert(s) and permanent protection of the latter against staining agents present in the outer layer of the sidewall, etc.

[0020] Thus, according to advantageous optional characteristics of the tire according to the invention, taken individually or according to all technically possible combinations:

[0021] - said at least one staining agent comprises an antioxidant, in particular 6PPD, and / or an oxidation product of an antioxidant, in particular 6PPDQ;

[0022] - the second elastomeric composition comprises at least 50 parts of one or more butyl rubbers;

[0023] - the second elastomeric composition comprises at least 75 parts, preferably at least 80 pieces, more preferably at least 90 pieces, of butyl rubber(s);

[0024] - the second elastomeric composition also comprises one or more rubbers natural, preferably includes between 10 pc and 20 pc of natural rubber(s);

[0025] - the second elastomeric composition has an oxygen permeability of "î oii O 1 1 at most 450 cm . mm. m . j .bar , preferably at most 300 cm . mm. m . j .bar , more preferably at most 165 cm3, mm. m 2. j '.bar1 ;

[0026] - said at least one anchoring member is arranged entirely at a distance from the structure interior;

[0027] - the vulcanized bonding interface has a radially outermost point which is located, along a radial direction of the tire, at a distance of less than 100 mm, preferably less than 50 mm, from the innermost radial point of the tire;

[0028] - it is provided that, in any meridian plane of the pneumatic, passing through said at less one anchoring member, (i) the vulcanized bonding interface and the external surface join at a radially external point and a radially internal point, which are arranged radially on either side of said at least one anchoring member, (ii) at said radially external point, the tangent to the vulcanized bonding interface and the tangent to the external surface form an angle of at most 75°, and (iii) at said radially internal point, the tangent to the vulcanized bonding interface and the tangent to the external surface form an angle of at most 75°;

[0029] - said at least one anchoring member forms, at least in part, at least one hollow which is shaped to receive and cooperate by complementary shapes with said at least one sidewall insert so as to hold said at least one sidewall insert in place when said at least one sidewall insert is attached to the tire, has a contact surface, which is adapted to be applied against said at least one sidewall insert when said at least one sidewall insert is attached to the tire and which at least partially delimits said at least one hollow, and separates the contact surface and the vulcanized bonding interface from each other, by being physically interposed between them;

[0030] - said at least one anchoring member has a minimum interposition thickness between the contact surface and the vulcanized bonding interface, which is at least 0.3 mm and preferably at most 4 mm, more preferably at most 2 mm;

[0031] - said at least one anchoring member comprises an external rim, from which said at least one hollow extends inward, and which extends from the external surface to said at least one hollow, joining the external surface in a flush manner;

[0032] - the outer rim has, on the radially outer side of said at least one hollow, a radial dimension of at most 10 mm, preferably at most 5 mm;

[0033] - said at least one hollow comprises several hollows which are respectively associated to sidewall inserts of said at least one sidewall insert, are distributed along a circumferential direction of the tire, and are separated two by two by a circumferential portion of said at least one anchoring member, arranged substantially flush with the external surface;

[0034] - the outer layer passes through said at least one anchoring element to open directly into said at least one hollow outside the contact surface.

[0035] The invention will be better understood upon reading the following description, given solely by way of example and with reference to the drawings in which:

[0036] - [Fig. 1] [Fig. 1] is a partial schematic section of a conforming tire to the invention, this section being in a cutting plane corresponding to a meridian plane of the tire;

[0037] - [Fig.2] [Fig.2] is a larger-scale view of the circled part II on the [Fig.l];

[0038] - [Fig.3] [Fig.3] is an elevation view along arrow III of [Fig.1], showing only a circumferential portion of the tire;

[0039] - [Fig.4] [Fig.5] Figures 4 and 5 are views respectively similar to figures 2 and 3, illustrating the tire after sidewall inserts have been added; and

[0040] - [Fig.6] [Fig.6] is a view similar to [Fig.4], illustrating a variant of construction of the pneumatic system shown in figures 1 to 5.

[0041] Figures 1 to 5 show a tire 100, which, in Figures 1 to 3, is shown alone and which, in Figures 4 and 5, is associated with sidewall inserts 200 attached externally to the tire 100, as explained in more detail later. In the figures, a geometric coordinate system is shown whose X, Y, and Z directions correspond respectively to the circumferential, axial, and radial directions of the tire 100, as defined in the introductory part of this document.

[0042] The tire 100 has a substantially toroidal shape about an axis of revolution substantially parallel to the axial direction Y. In the example illustrated in the figures, the tire 100 is intended for a motor vehicle, typically a four-wheeled vehicle. However, the tire 100 is more generally intended for a light vehicle, particularly a passenger vehicle, possibly a two-wheeled vehicle.

[0043] As shown in [Fig.1], the tire 100 includes a top 102 having a tread 104, which extends in the circumferential direction X over the entire circumference of the tire 100 and which is intended to come into contact with the ground when rolling the tire 100.

[0044] The tire 100 also includes two sidewalls 106, each extending radially inward from the apex 102 and arranged axially on either side of a median plane M of the tire 100, this median plane being as defined in the introductory part of this document. The tire 100 further includes two bead 108, which are opposite each other with respect to the median plane M and which respectively extend the two sidewalls 106 radially inward. Thus, one of the two sidewalls 106 connects one of the two bead 108 to the apex 102, and the other sidewall 106 connects the other bead 108 to the apex 102. The bead 108 allows the tire 100 to be attached to a mounting support 10, for example a wheel rim, as schematically illustrated in dotted lines in [Fig. 1]. Note that, in [Fig. 1], only one of the two sidewalls 106 and its associated bead 108 are shown, the [Fig. 1].l] thus corresponding to a half meridional section of the 100 tire. .

[0045] The apex 102, the two flanks 106 and the two ridges 108 together define a toroidal cavity 110 of the tire 100, delimited by a surface internal 112 of the tire 100. This toroidal cavity 110 allows the tire 100 to be inflated when the latter is mounted on the mounting support 10. In the mounted state of the tire 100 on the mounting support 10, the toroidal cavity 110 is closed jointly by the tire 100 and the mounting support 10, so that it can be pressurized by an inflation gas, which is introduced into the toroidal cavity 110 and with which the internal surface 112 is then in contact.

[0046] The rest of the description relates to the flank 106 and its associated ridge 108, visible in [Fig.1].

[0047] As can be clearly seen in Figures 1 to 3, the flank 106 has an outer layer 120 which is separated from the toric cavity 110 by an inner structure 122 of the flank 106, which, opposite the outer layer 120, carries a part of the inner surface 112. Opposite the inner structure 122, the outer layer 120 carries an outer surface 124 which is in contact with the atmospheric air. Axially, the outer layer 120 extends from the outer surface 124 to the inner structure 122 with which it forms a vulcanized bonding interface 126. Radially, the outer layer 120 extends between the apex 102 and the bead 108, or, as here, from the apex 102 to the bead 108. In particular, the outer surface 124 and the vulcanized bonding interface 126 each extend radially from the apex 102 to the bead 108.

[0048] The outer layer 120 is made of an elastomeric composition whose specifications are not limiting, provided that this elastomeric composition is suitable for its use in the relevant part of the tire, namely the outer part of the sidewall. By way of non-limiting example, the elastomeric composition of the outer layer 120 comprises one or more natural rubbers and one or more butadiene rubbers, for example, 40 parts per cent of the natural rubber(s) and 60 parts per cent of the butadiene rubber(s). As is well known in the field, "part per cent" or "parts per cent of elastomer" means the weight portion of a constituent per hundred weight portions of the elastomer(s), that is, of the total weight of the elastomer(s) in the composition under consideration; thus, a 60-part constituent means, for example, sixty grams of that constituent per one hundred grams of elastomer(s).The elastomeric composition of the outer layer 120 also includes constituents other than elastomers, typically fillers and additives, although this is not a limiting factor. In all cases, among these other components, the elastomeric composition of the outer layer 120 includes one or more staining agents, that is, agents which, in use, tend to induce visible stains, in other words, color inconsistencies. In practice, these staining agents are present in the elastomeric composition of the outer layer 120 not for their staining effect, which is undesirable, but for at least one other desired effect. within this elastomeric composition. As an example, one or more of these staining agents is 6PPD and / or its oxidation product 6PPDQ: 6PPD, whose formula is N-(l,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, is a chemical antioxidant whose desired effect within the elastomeric composition of the outer layer 120 is to prevent the degradation / decomposition of this elastomeric composition, by inhibiting the appearance and propagation of cracking in the outer layer 120; when 6PPD is exposed to air, it can react with ozone to create 6PPDQ, otherwise known as 6PPD-quinone. Of course, other staining agents besides 6PPD and / or 6PPDQ may be present in the elastomeric composition of the outer layer 120, in particular one or more antioxidants, other than 6PPD, and / or one or more oxidation products of such antioxidants, other than 6PPDQ.

[0049] As regards the internal structure 122 of the flank 106, its compositional and structural specifications are not limiting, provided that this internal structure 122 forms, with the external layer 120, the vulcanized bonding interface 126. In a manner well known in the field, the internal structure 122 comprises several superimposed layers which succeed one another from the vulcanized bonding interface 126 to the internal surface 112. These superimposed layers of the internal structure 122 typically include one or more reinforcing layers, each of which comprises reinforcements embedded in an elastomeric mixture. Moreover, as is customary in the field and as schematically illustrated in [Fig.1], this internal structure 122 of the flank 106 extends both into the bulge 108 and the top 102, as well as to the other flank 106 and the other bulge 108.

[0050] As shown in [Fig.1] and as particularly visible in [Fig.2], the side 106 further includes an anchoring member 130 which, as explained in more detail later, allows the attached side inserts 200 to be mechanically retained.

[0051] The anchoring member 130 is made of an elastomeric composition, which, while being different from the elastomeric composition of the outer layer 120, allows the anchoring member 130 to be integrated into the outer layer 120, forming with the latter a vulcanized bonding interface 132 which, as clearly visible in [Fig.2], extends into the thickness of the outer layer 120 from the outer surface 124 of the latter. The anchoring member 130 thus occupies, along the axial direction Y, an axial portion of the outer layer 120, extending from the outer surface 124 towards the inner structure 122, and, along the radial direction Z, a radial portion of the outer layer 120, arranged between and at a distance from the apex 102 and the bead 108. Along the circumferential direction X, the anchoring member 130 extends over at least a circumferential portion of the outer layer, as clearly visible in the [Fig.3] : in the embodiment considered here, the anchoring member 130 thus runs continuously over the entire circumference of the tire 100, being . noted that other forms of implementation are conceivable, as mentioned at the end of the description.

[0052] The vulcanized bonding interface 132 and the external surface 124 meet on either side, along the radial direction Z, of the anchoring member 130, forming two circumferential lines that are radially separated from each other, namely a radially external circumferential line L1 and a radially internal circumferential line L2, as clearly visible in Figures 2 and 3. The circumferential lines L1 and L2 extend overall along the circumferential direction X, it being noted that, in practice, particularly in connection with considerations of tire manufacturing 100, the exact direction in which each of these circumferential lines L1 and L2 extends may deviate slightly, typically by only a few degrees, from the circumferential direction X per wheel revolution. In the plane of [Fig.[2], which corresponds to a meridian plane of the tire 100, the radially external circumferential line L1 and the radially internal circumferential line L2 intersect this meridian plane, forming points PI and P2 respectively. Here, the circumferential lines L1 and L2 are substantially circular and centered on the axis of rotation of the tire 100, thus being substantially parallel to each other; in unrepresented variants, other geometric specificities are conceivable for the circumferential lines L1 and L2. In all cases, in any meridian plane passing through the anchoring member 130, which, here, amounts to saying in any meridian plane of the tire 100, the tangents, at point PI, respectively to the vulcanized bonding interface 132 and to the external surface 124 form an angle Al and the tangents, at point P2, respectively to the vulcanized bonding interface 132 and to the external surface 124 form an angle A2, as shown in the [Fig.2] : advantageously, each of the angles Al and A2 is different from 90°, being preferably less than 75°, which, in use, delays or even avoids the initiation of cracking of the vulcanized bond interface 132 at the level of the circumferential lines L1 and L2. .

[0053] From the circumferential lines L1 and L2, the vulcanized bonding interface 132 is embedded in the thickness of the outer layer 120, thus approaching axially the inner structure 122. According to an advantageous arrangement, which is implemented in the embodiment illustrated in the figures, the vulcanized bonding interface 132 thus extends to the vicinity of the vulcanized bonding interface 126, without however coming into contact with the latter: in other words, the anchoring member 130 is arranged entirely at a distance from the inner structure 122, in particular without forming a contact interface with the latter, which reinforces the structural cohesion of the flank 106, in particular by preventing the anchoring member 130 from forming different bonding interfaces with the rest of the flank 106.

[0054] In practice, in particular to minimize in use the intensity of mechanical stresses at the vulcanized bonding interface 132 and thus strengthen, at the level of the latter, the structural cohesion of the flank 106, it is advantageously provided that the vulcanized bonding interface 132 does not have a protruding edge, but that it has, at every point, a radius of curvature of at least 0.5 mm, preferably of at least 1 mm.

[0055] Within the sidewall 106, it is preferable that the vulcanized bonding interface 132 be arranged as close as possible radially to the bead 108. In this way, during use, the mechanical stresses applied to the vulcanized bonding interface 132 remain as low as possible. Thus, an advantageous dimensioning provides that a distance Dl, measured along the radial direction Z between the innermost radial point P100 of the tire 100 and the outermost radial point of the vulcanized bonding interface 132, which, in the embodiment considered here, lies on the outermost radial circumferential line L1 and corresponds to the outermost radial point PI on [Fig. 2], is less than 100 mm, preferably less than 50 mm. In other words, the distance Dl is equal to or less than 100 mm, preferably 50 mm.

[0056] In all cases, the elastomeric composition of the anchoring element 130 is designed to inhibit the migration of the staining agents contained in the elastomeric composition of the outer layer 120. In other words, the elastomeric composition of the anchoring element 130 forms an anti-migration barrier against these staining agents, substantially limiting, or even blocking, their propagation within this elastomeric composition. In practice, the physicochemical mechanism(s) underlying this anti-migration barrier effect are not limiting, as long as the elastomeric composition of the anchoring element 130 implements them by reacting / interfering with the staining agents which, originating from the elastomeric composition of the outer layer 120, migrate towards the anchoring element through the vulcanized bonding interface 132.

[0057] According to a preferred embodiment, ensuring the anti-migration barrier effect, the elastomer(s) of the elastomeric composition of the anchoring member 130 comprise predominantly by weight one or more butyl rubbers. In other words, the elastomeric composition of the anchoring member 130 comprises at least 50 parts per cent of the butyl rubber(s). The anti-migration barrier effect is all the more pronounced as the proportion of butyl rubber(s) is greater in the elastomeric composition of the anchoring member 130: thus, the elastomeric composition of the anchoring member 130 preferably comprises at least 75 parts per cent, preferably at least 80 parts per cent, and more preferably at least 90 parts per cent, of the butyl rubber(s). In all cases, the butyl rubber(s) represent in practical at least 40%, or even at least 45%, by weight of the elastomeric composition of the anchoring organ 130.

[0058] It should be noted that, in this document, "butyl rubber" means an isobutylene homopolymer or an isobutylene-isoprene copolymer, as well as halogenated derivatives, in particular generally brominated or chlorinated, of these isobutylene homopolymers and isobutylene-isoprene copolymers. Preferably, the butyl rubber(s) usable in the elastomeric composition are selected from isobutylene rubbers, isobutylene-isoprene copolymers (IIR), bromobutyl rubbers such as bromoisobutylene-isoprene copolymer (BIIR), and chlorobutyl rubbers such as chloroisobutylene-isoprene copolymer (CIIR).By extension of the previous definition, the term "butyl rubber" will also include copolymers of isobutylene and styrene derivatives such as isobutylene and brominated methylstyrene (BIMS) copolymers, which notably include the elastomer called EXXPRO marketed by Exxon.

[0059] According to an advantageous optional provision, the elastomeric composition of the anchoring element 130 comprises, in addition to the butyl rubber(s), one or more natural rubbers which, by virtue of their remarkable adhesive properties, render the vulcanized bonding interface 132 particularly strong. Thus, the elastomeric composition of the anchoring element 130 preferentially comprises between 10 and 20 parts of the natural rubber(s). It should be noted that, in this document, "natural rubber" means a material obtained by processing the latex secreted by certain plants, such as the rubber tree. The natural rubber(s), which are usually designated NR, are as defined in ASTM D1418.

[0060] Alternative embodiments to the embodiment detailed above are conceivable for the elastomeric composition of the anchoring member 130. Thus, rather than characterizing the various possible embodiments for the elastomeric composition of the anchoring member 130 by its constituents, it is conceivable to characterize the elastomeric composition of the anchoring member 130 by physicochemical parameters which are relevant in relation to the anti-migration barrier effect.

[0061] A first possibility for corresponding characterizations is based on the oxygen permeability of the elastomeric composition of the anchoring element 130. By quantifying this oxygen permeability according to ASTM D3985 and under standardized temperature and pressure conditions, the oxygen permeability of the elastomeric composition of the anchoring element 130 is advantageously at most 450 cm⁻¹ mm⁻¹ m⁻¹ j⁻¹ bar, preferably at most 300 cm⁻¹ mm⁻¹ m⁻¹ j⁻¹ bar, plus preferably at most 165 cm3, mm. m2. j '.bar '. In other words, the oxygen permeability of the elastomeric composition of the anchoring element 130 is equal to or less than 450 cm . mm. m . j .bar , preferably 300 cm . mm. m . j .bar , more preferably 165 cm3, mm. m2. j '.bar '.

[0062] Other possibilities for corresponding characterizations may be based on other relevant physicochemical parameters.

[0063] As indicated above, the anchoring member 130 mechanically retains the sidewall inserts 200 attached to the tire 100. To this end, in the embodiment illustrated in Figures 1 to 5, the anchoring member 130 forms recesses 140, each extending through the thickness of the anchoring member 130, opening onto the outside of the sidewall 106 where they each communicate freely with the atmospheric air. As can be clearly seen by comparison between Figures 3 and 5, each of the recesses 140 is associated with one of the sidewall inserts 200 to be retained: thus, each recess 140 is capable of mechanically retaining one sidewall insert among the sidewall inserts 200, it being already noted that variations in this respect are conceivable, as mentioned at the end of the description.

[0064] In the illustrated embodiment, the hollows 140 are identical to each other, although this may be otherwise in variants not shown, and, as clearly visible in [Fig. 3], are distributed along the circumferential direction X of the tire 100, being separated in pairs by a circumferential portion 134 of the anchoring member 130. The circumferential portions 134 are thus distributed along the circumferential direction X. Here, the circumferential distribution of the hollows 140 and the circumferential portions 134 is regular, but this may be otherwise in variants.In all cases, when the anchoring element 130 is made from a strip, which is assembled to the rest of a raw band designed to obtain the tire 100 after curing and whose opposite circumferential ends are welded to each other during assembly to the rest of the raw band, the corresponding weld is advantageously provided in one of the circumferential portions 134 and not at the level of one of the hollows 140: indeed, the sidewall insert 200 associated with the latter would then risk being stained due to an alteration, or even a break in the anti-migration barrier effect at the level of the aforementioned weld. Furthermore, the circumferential portions 134 advantageously meet the external surface 124 of the outer layer 120, which, externally to the flank 106, gives an impression of continuity of material, along the radial direction Z, between the outer layer 120 and the anchoring element 130 at the level of the circumferential portions 134. .

[0065] Each hollow 140, which is here formed entirely by the anchoring member 130, is shaped to receive and cooperate by complementary shapes with the side insert 200 associated, so as to hold this sidewall insert 200 in place when the latter is attached to the tire 100. The sidewall inserts 200 are thus respectively clip-on or snap-on into the recesses 140. For this purpose, as clearly visible in [Fig. 2], each recess 140 is at least partially delimited by a contact surface 136 fully supported by the anchoring member 130. As clearly visible in [Fig. 4], this contact surface 136 is applied against the sidewall insert 200 when the latter is attached to the tire 100. Thus, to ensure the mechanical retention of the attached sidewall insert 200, the latter is wedged or clipped in place by contact / support with the contact surface 136, which then mechanically interferes with the sidewall insert 200 to prevent the latter from moving relative to the sidewall 106 and, therefore, relative to the tire 100.In practice, the contact surface 136 can thus be applied against the added sidewall insert 200 either in direct contact or with the localized interposition of an adhesive film. Furthermore, the complementary shape of the contact surface 136 and the sidewall insert 200 is advantageously reversible, making the sidewall insert 200 removable relative to the sidewall 106. Moreover, it is understood that, beyond the embodiment illustrated in the figures, multiple geometries are conceivable for the contact surface 136. In all cases, the contact surface 136 helps to hold the added sidewall insert 200 in place within the corresponding recess 140, particularly during the rolling of the tire 100, when this sidewall insert is liable to be ejected.Furthermore, each hollow 140 allows the associated side insert 200 to be arranged directly in the thickness of the anchoring element 130 and, thereby, indirectly in the thickness of the outer layer 120, so as not to disturb the airflow on the outside of the side 106 in the vicinity of the side insert 200.

[0066] In all cases, the anchoring member 130 is physically interposed between the contact surface 136 and the vulcanized bonding interface 132, so that the latter are materially separated from each other by the anchoring member 130. Thus, the anchoring member 130 forms between the contact surface 136 and the vulcanized bonding interface 132 a physical barrier within which the aforementioned anti-migration barrier effect protects the reported side insert 200 against the staining phenomenon mentioned above. In practice, as illustrated in the cross-section of [Fig.2], this physical barrier, formed by the anchoring member 130 between the contact surface 136 and the vulcanized bonding interface 132, has a thickness, measured at the shortest point between the contact surface 136 and the vulcanized bonding interface 132, which is variable when traversing the contact surface 136 and the vulcanized bonding interface 132.Following a preferential dimensioning, which makes the material separation between the contact surface 136 and the vulcanized bonding interface 132 reliable by the anchoring element 130, the latter has a minimum thickness Emin of interposition between. the contact surface 136 and the vulcanized bonding interface 132, which is at least 0.3 mm. To avoid oversizing the anchoring element 130, and thus limit its bulk relative to the rest of the tire 100, in particular the outer layer 120, this minimum thickness Emin is preferably at most 4 mm, more preferably at most 2 mm.

[0067] In practice, as in the embodiment illustrated in the figures, each groove 140 is bordered, here completely, by an external rim 138 of the anchoring member 130, from which the groove 140 extends inward. As clearly visible in [Fig. 2], each external rim 138 extends from the external surface 124 to the corresponding groove 140, advantageously joining the external surface flush. The presence of the anchoring member 130 thus does not induce any protruding discontinuity on the outside of the sidewall 106, which does not affect the aerodynamic drag of the tire 100 and, consequently, its resistance to forward motion.According to a preferred dimensioning, each external rim 138 has, on the radially external side of the corresponding hollow 140, a radial dimension D2 of at most 10 mm, preferably at most 5 mm: the anchoring element 30 thus has a radially external footprint, which is controlled, which helps to avoid applying strong mechanical stresses to the radially external part of the vulcanized bonding interface 132.

[0068] In the embodiment illustrated in Figures 1 to 5, each hollow 140 is delimited by:

[0069] - two lateral walls 142, which are radially separated from each other and which each extend from the outer rim 138 into the thickness of the anchoring member 130, it being noted that, here, these two lateral walls 142 carry part of the contact surface 136 associated with the hollow 140 and are formed entirely by the anchoring member 130,

[0070] - a bottom wall 144 which, opposite the opening of the hollow 140 onto the edge external 138, connects the two lateral walls 142 to each other, it being noted that, here, this bottom wall 144 carries part of the contact surface 136 associated with the hollow 140 and is formed entirely by the anchoring element 130,

[0071] - a protuberance 146, here mushroom-shaped, which extends outward from the bottom wall 144 towards the opening of the hollow 140 on the outer rim 138, and which is arranged between and at a distance from the lateral walls 142, it being noted that, here, this protrusion 146 carries part of the contact surface 136 associated with the hollow 140 and is formed entirely by the anchoring member 130, and

[0072] - two end walls 148, which are separated from each other along the direction circumferential X and which each connect to the other the two lateral walls 142, it being noted that, here, these two end walls 148 carry part of the contact surface 136 associated with the hollow 140 and are formed entirely by the anchoring element 130.

[0073] Here, as clearly seen in [Fig.3], the protuberance 146 extends, along the circumferential direction X, continuously from one to the other of the two end walls 148. In variants not shown, this protuberance extends, along the circumferential direction X, discontinuously, forming in particular two or more disjoint circumferential portions, one and / or the other of the two circumferential portions furthest from each other being either adjoining the two end walls 148, or separated from them.

[0074] Furthermore, preferred dimensions for the embodiment of the hollows 140, detailed just above, are provided in WO2022 / 069831 and WO2022 / 069832 to which the reader may refer, and are therefore not reproduced in full in this document.

[0075] The specifics of the side inserts 200 are not limiting as long as each insert is able to cooperate with the anchoring member 130 for the purpose of its mechanical retention to the latter, as explained above.

[0076] Thus, the constituent material of the side inserts 200 is not limiting. In practice, each side insert 200 preferably comprises one or more polymeric materials, in particular rubber, silicone and / or a thermoplastic polymer, such as polyurethane.

[0077] In all cases, each side insert 200 advantageously has a color and / or surface texture that differs from that of the anchoring member 130, for obvious aesthetic reasons of differentiation. At the same time, it is understood that, preferably, the anchoring member 130 and the external surface 124 have substantially the same color, typically black, and the same surface texture, so that, externally to the side 106, the anchoring member 130 is visually indistinguishable or virtually indistinguishable from the external surface 124.

[0078] Figure 6 shows, as an alternative embodiment of the tire 100, a tire 100' in which one sidewall 106' is distinguished from the sidewall 106 of the tire 100 by an outer layer 120' and an anchoring element 130', which are respectively functionally similar to the outer layer 120 and the anchoring element 130, while being structurally distinct from them. More specifically, the anchoring element 130' has a contact surface 136', which is functionally similar to the contact surface 136 and which partially delimits a groove 140', functionally similar to each groove 140 but formed only partially by the anchoring element 130'. The remainder of the 140' hollow is formed by the outer layer 120', more precisely is delimited by a part 121' of the latter, which crosses the anchoring element 130' to open directly into the hollow 140' outside the contact surface 136', as clearly visible in [Fig. 6]. Here, this portion 121' of the outer layer 120' partially forms both a bottom wall and a protrusion of the hollow 140', respectively similar to the bottom wall 144 and the protrusion 146, opening into the hollow 140' at the top of the protrusion, which is shaped here concavely so as not to bear the contact surface 136' and thus create a free volume between the portion 121' of the outer layer 120' and the side insert 200 when the latter is placed in the hollow 140'. The anchoring element 130' and the aforementioned free volume together prevent any direct contact between the outer layer 120', including its portion 121', and the placed side insert 200.Regardless of the specific geometry and / or arrangement of part 121' of the outer layer 120', the fact that the latter opens, through its part 121', into the hollow 140' limits the risk of trapping air or gas bubbles between the outer layer 120' and the anchoring element 130' during the curing of the tire 100'.

[0079] Furthermore, taking into account the explanations given so far in connection with the embodiment of figures 1 to 5 and with the variant embodiment of [Fig.6], it is understood that, whatever the embodiment of the anchoring members 130 and 130', the latter make it possible to mechanically retain the added flank inserts 200 so as to keep each of them at a distance from the outer layer 120, 120'. In the case of the anchoring element 130, this maintaining distance between each side insert 200 and the outer layer 120 is achieved essentially, or even exclusively, by materially interposing the anchoring element 130 between them, while, in the case of the anchoring element 130', this maintaining distance between each side insert 200 and the outer layer 120' is achieved partly by materially interposing the anchoring element 130' between them and partly by providing a free volume between them.

[0080] Finally, various modifications and variations to the 100 and 100' tires described so far are conceivable. For example:

[0081] - as alternatives to the embodiment of the hollows 140 and 140', detailed above, multiple forms of realization are conceivable for hollows 140 and 140', in particular with protuberance 146 other than in mushroom shape or without such a protuberance;

[0082] - rather than the anchoring member 130 or 130' forming several hollows 140 or 140', a single hollow may be provided, this single hollow extending over all or part of the circumference of the 100 or 100' tire and being associated with a single sidewall insert such as the 200 sidewall inserts;

[0083] - rather than the anchoring member 130 or 130' extending continuously over the entire The circumference of the tire, 100 or 100', the anchoring device extends either only over a single circumferential portion of the tire, or over several portions circumferential of the tire, disjointed in pairs, which, in the latter case, amounts to saying that the corresponding sidewall of the tire includes several anchoring elements distributed along the circumferential direction X, each of the latter forming one or more hollows similar to the hollows 140 and 140';

[0084] - to protect the peripheral edge of the mounting bracket 10, the side 106 or 106' advantageously incorporates a protective bead, which can either be formed at least in part by the anchoring element 130 or 130', as in the example illustrated in the figures, or be formed independently of the anchoring element 130 or 130', typically entirely by the outer layer 120 or 120'; in this respect, the various arrangement / positioning possibilities in connection with such a protective bead, which are disclosed in WO2022 / 069831, WO2022 / 069832 and PCT / EP2024 / 057909, are applicable to the flank 106 or 106', mutatis mutandis; and / or

[0085] - as mentioned above, what has been described so far for the first of the flanks 106 or 106' of the 100 or 100' tire may either not be applied to the second sidewall of the tire, typically when the tire is intended for a motor vehicle, or be applied to the second sidewall of the tire, typically when the tire is intended for a two-wheeled vehicle.

Claims

Demands

1. A tire (100; 100') comprising two sidewalls (106; 106') connecting a crest (102) to two ridges (108) adapted for attaching the tire to a mounting bracket (10), at least one of the two sidewalls (106; 106') comprising: - an outer layer (120; 120') which: - has an external surface (124) in contact with atmospheric air, - extends radially between the crest (102) and the corresponding ridge (108), - extends axially from the external surface (124) to an internal structure (122) of the sidewall (106; 106'), and - is made of a first elastomeric composition comprising at least one staining agent, and - at least one anchoring element (130; 130') which is: - made of a second composition elastomeric, which is different from the first elastomeric composition and which inhibits the migration of said at least one staining agent, - integrated into the outer layer (120;120'), forming with it a vulcanized bonding interface (132) which extends from the external surface (124) into the thickness of the outer layer, and - adapted to mechanically retain at least one sidewall insert (200), attached externally to the tire (100; 100'), so as to keep said at least one sidewall insert away from the outer layer (120; 120').;

2. Pneumatic according to claim 1, wherein said at least one staining agent comprises an antioxidant, in particular 6PPD, and / or an oxidation product of an antioxidant, in particular 6PPDQ.

3. Pneumatic according to any one of claims 1 or 2, wherein the second elastomeric composition comprises at least 50 parts of one or more butyl rubbers.

4. Pneumatic according to claim 3, wherein the second elastomeric composition comprises at least 75 parts, preferably at least 80 parts, more preferably at least 90 parts, of the butyl rubber(s).

5. Pneumatic according to any one of claims 3 or 4, wherein the second elastomeric composition also comprises a or natural rubbers, preferably comprising between 10 pc and 20 pc of the natural rubber(s).

6. Pneumatic according to any one of the preceding claims, wherein the second elastomeric composition has an oxygen permeability of at most 450 cm3, mm. m2. j '.bar ', preferably at most 300 cm3, mm. m2. j '.bar ', more preferably at most 165 cm3, mm. m 2. j '.bar '.

7. Pneumatic according to any one of the preceding claims, wherein said at least one anchoring member (130; 130') is arranged entirely at a distance from the internal structure (122).

8. Tire according to any one of the preceding claims, wherein the vulcanized bonding interface (132) has a radially outermost point (PI) which is located, along a radial direction (Z) of the tire (100; 100'), at a distance (Dl) of less than 100 mm, preferably less than 50 mm, from the radially innermost point (P 100) of the tire.

9. A tire according to any one of the preceding claims, wherein, in any meridian plane of the tire (100; 100'), passing through said at least one anchoring member (130; 130'): - the vulcanized bonding interface (132) and the external surface (124) join to form a radially external point (PI) and a radially internal point (P2), which are arranged radially on either side of said at least one anchoring member (130; 130'), - at said radially external point (PI), the tangent to the vulcanized bonding interface (132) and the tangent to the external surface (124) form an angle (A1) of at most 75°, and - at said radially internal point (P2), the tangent to the vulcanized bonding interface (132) and the tangent to the external surface (124) form an angle (A2) with a value of at most 75°.

10. A tire according to any one of the preceding claims, wherein said at least one anchoring member (130; 130'): - forms, at least in part, at least one recess (140; 140') which is shaped to receive and cooperate by complementary shapes with said at least one sidewall insert (200) so as to hold said at least one sidewall insert in place when said at least one sidewall insert is attached to the tire (100; 100'), - carries a contact surface (136; 136'), which is adapted to be applied against said at least one sidewall insert (200) when said at least one sidewall insert is attached to the tire (100; 100') and which at least partially delimits said at least one recess (140; 140'), and - separates the contact surface (136; 136') and the vulcanized bonding interface (132) from each other, by being physically interposed between them.

11. Pneumatic according to claim 10, wherein said at least one anchoring member (130; 130') has a minimum thickness (Emin) of interposition between the contact surface (136; 136') and the vulcanized bonding interface (132), which is at least 0.3 mm and preferably at most 4 mm, more preferably at most 2 mm.

12. Pneumatic according to any one of claims 10 or 11, wherein said at least one anchoring member (130; 13') has an external rim (138): - from which said at least one hollow (140; 140') extends in retreat, and - which extends from the external surface (124) to said at least one hollow (140; 140'), joining the external surface in a flush manner.

13. Pneumatic according to claim 12, wherein the outer rim (138) has, on the radially outer side of said at least one hollow (140; 140'), a radial dimension (D2) of at most 10 mm, preferably at most 5 mm.

14. A tire according to any one of claims 10 to 13, wherein said at least one hollow comprises several hollows (140; 140') which: - are respectively associated with sidewall inserts (200) of said at least one sidewall insert, - are distributed along a circumferential direction (X) of the tire (100; 100'), and - are separated two by two by a circumferential portion (134) of said at least one anchoring member (130; 130'), arranged substantially flush with the external surface (124).

15. Pneumatic according to any one of claims 10 to 14, wherein the outer layer (120') passes through said at least one anchoring member (130') to open directly into said at least one hollow (140') outside the contact surface (136').

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