Tire including a discontinuous-grip sidewall insert

Abstract

The present invention relates to a tire (1) comprising at least one sidewall (3), intended to cooperate with a discontinuous sidewall insert, comprising at least one insert portion, by means of an anchoring means (6) comprising at least one anchoring portion. Each anchoring portion comprises a recess (7), formed in an outer layer of sidewall and delimited by two circumferential walls, respectively radially inner (72) and radially outer (73), and a protrusion (8), projecting from the bottom of the recess. According to the invention, the protrusion (8) of any anchoring portion comprises at least two disjointed protrusion portions (81) distributed circumferentially along the circumferential mean line (Lm) of the anchoring portion. Fig. 3

Description

Title of the invention: Tire comprising a discontinuously hooked sidewall insert

[0001] The present invention relates to a tire, intended more particularly to equip a light four-wheeled vehicle (car, van), or a two-wheeled vehicle (motorcycle), and comprising at least one sidewall including a sidewall insert, intended to personalize the design of the tire sidewall.

[0002] A common concern of vehicle manufacturers and users is to personalize the design of tire sidewalls by means of colour and / or additional elements, referred to as inserts in this document.

[0003] A known colored means is a colored rubber compound, for example, white, contained in the sidewall of the tire and contrasting with the black color of the adjacent rubber compounds. However, this technical solution has several drawbacks. First, certain chemical components, such as protective compounds, contained in the rubber compounds adjacent to the colored means, can migrate into the colored rubber compound and cause it to gradually discolor over time. Furthermore, sidewall deformations during the tire's lifespan can initiate cracking in the colored rubber compound and degrade its appearance. In addition, the mechanical means used to mount the tire onto its rim, by rubbing against the colored rubber compound, can also degrade it.Finally, manufacturing a tire with sections of different colors is more complex industrially.

[0004] US patent 3128815 describes an insert in the form of a tire lining element intended to be removably engaged in a sidewall. This lining element can be attached to the sidewall by various means, such as engaging its ends in the sidewall, or hooking its ends by means of anchors that are 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 surface, and is positioned more particularly in the radially inner part of the sidewall, between the outermost axial point of the sidewall and the rim edge. However, this lining element is susceptible to deformation and detachment from the sidewall during tire rolling because it is positioned in an area of ​​high tire flex.

[0005] Document JPH11151918 describes another removable coloured insert intended to be fixed to a tire sidewall, in the radially outer part of the sidewall, near the tread, thanks to a recessed attachment mechanism relative to the sidewall surface. However, such an attachment mechanism does not allow for easy mounting of this insert on the tire when mounted on its rim and inflated, as the geometry of the insert may be mismatched with the geometry of the recess in the attachment mechanism, depending on the inflation pressure or the rim width. Furthermore, during driving, the tightness of the insert against the sidewall can change, for example under strong lateral acceleration, with a risk of the insert being ejected.

[0006] Document WO 2022069831Al describes a tire comprising at least one sidewall, intended to cooperate with a sidewall insert via an anchoring means, and aims to personalize the design of said tire sidewall. According to the invention, the anchoring means, comprising a recess formed in an outer layer of the sidewall, includes a protrusion, raised above the bottom of the recess and extending from the bottom of the recess to the vicinity of the outer face of the sidewall. The protrusion has, in any meridian plane, a minimum width Lpmin in the vicinity of the bottom of the recess so as to ensure the anchoring of the sidewall insert intended to cooperate with the anchoring means. The sidewall insert described in this document allows for easier mounting and improved attachment to the sidewall.

[0007] Document WO 2022069832A1 describes a particular embodiment of a tire, as described in document WO 2022069831A1, in which the anchoring means, comprising a hollow formed in an outer layer of sidewall, includes a protrusion, raised relative to the bottom of the hollow and extending from the bottom of the hollow to the vicinity of the outer face of the sidewall, and the protrusion is made up of a staggered arrangement of a first narrow portion having a minimum width Lpmin and a second wide portion having a maximum width Lpmax, such that the difference Lpmax-Lpmin is at least equal to 1 mm and at most equal to 4 mm.

[0008] Generally speaking, whatever the type of sidewall insert as described in the aforementioned documents, its retention on the sidewall of the tire, during the rolling of the tire, is a constant concern and requires a reliable anchoring means.

[0009] Furthermore, there are manufacturing tolerances for any sidewall insert. For example, for a sidewall insert with a theoretical length of 2000 mm, intended to cooperate with a tire sidewall over a circumferential length of the anchoring means equal to 2000 mm, a manufacturing tolerance of 1% for the sidewall insert leads to a variation in its length of up to 20 mm, either under- or over-. For a sidewall insert length greater than the circumferential length of the anchoring means, the excess sidewall insert length cannot be correctly positioned in the anchoring means. Conversely, for a sidewall insert length If the sidewall insert is shorter than the circumference of the anchoring device, it cannot fully cover its circumference. Therefore, mounting a sidewall insert on a tire sidewall remains a delicate operation.

[0010] Consequently, the inventors have set themselves the objective of proposing a tire suitable for being equipped with at least one sidewall insert, with an anchoring means facilitating the mounting of the sidewall insert and guaranteeing a satisfactory and lasting attachment to the sidewall while driving.

[0011] This objective has been achieved by a tire for a light vehicle, intended to be mounted on a rim and suitable for being equipped with at least one sidewall insert, said tire having a nominal section of height H and an axis of rotation defining an axial direction, and comprising: -two sides connecting a vertex to two ridges, each designed to come into contact with the rim, -at least one side comprising an anchoring means, intended to cooperate with a side insert, -the anchoring means comprising at least one anchoring portion having a circumferential mean line extending in a circumferential direction, -at least one anchoring portion comprising a hollow, formed in an outer flank layer, in contact with atmospheric air, said outer flank layer comprising at least one rubbery material and extending from an outer flank face towards the interior of the flank, -the hollow having a hollow bottom and being delimited by a radially inner circumferential wall, closest to the axis of rotation of the tire, and by a radially outer circumferential wall, furthest from the axis of rotation of the tire, -the hollow having, in any meridian plane containing the axis of rotation of the tire, a depth Pc, maximum distance measured perpendicularly between the outer face of the sidewall and the bottom of the hollow, at least equal to 2 mm, and a width Le, measured at the level of the outer face of the sidewall, along a line perpendicular to the two circumferential walls respectively radially inner and radially outer, -at least one anchoring portion including a protrusion, raised above the bottom of the hollow and extending from the bottom of the hollow to the vicinity of the outer face of the flank, -the protrusion of any anchoring portion comprising at least two disjointed protrusion portions distributed circumferentially along the circumferential mean line of the anchoring portion.

[0012] The object of the invention is to provide a tire in which at least one of the sidewalls can be equipped with a substantially circumferential sidewall insert, intended to personalize the tire's design, and in which the protrusion of any anchoring portion comprises at least two disjointed protrusion portions distributed circumferentially along the circumferential mean line of the anchoring portion. In other words, said protrusion has discontinuities.

[0013] In the particular case where the side insert, intended to cooperate with a given anchorage portion, includes additional fastening means, such as, for example, pins, a first advantage of these discontinuities in the protrusion of said anchorage portion, compared to a continuous protrusion, is to allow the introduction of the additional fastening means of the side insert into all or part of the discontinuities in the protrusion of the anchorage portion, which makes it easier to manage the variations in length of the side insert, inherent in the manufacturing tolerances of the side insert, when it is placed in the anchorage portion and to ensure a more aesthetic positioning of the side insert.

[0014] In this same cooperation configuration between a sidewall insert and its anchoring means via complementary fastening means, a second advantage is to ensure the durability of the sidewall insert's retention during tire rolling.

[0015] Assuming that a film of adhesive is applied between the protrusion of a given anchor portion and the side insert, in order to ensure better fixation of the latter to the anchor portion, a third advantage of these protrusion discontinuities is improved management of any excess adhesive. Indeed, when manually gluing a side insert, it is not always easy to perfectly control the amount of adhesive deposited on the protrusion. Excess adhesive may overflow and escape from the recess of the anchor portion, which could cause a stain on the side and / or the side insert. Thus, the presence of discontinuities in the protrusion acts as a reservoir, storing any excess adhesive and preventing it from overflowing outside the anchor portion and staining the side and / or the side insert.

[0016] According to a first embodiment, the anchoring means comprises a single anchoring portion continuous over the entire circumference. In this case, the anchoring means constitutes a complete ring on the sidewall of the tire.

[0017] According to a second embodiment, the anchoring means comprises at least one anchoring portion circumferentially delimited by a first end wall and a second end wall. In other words, the anchoring means comprises either a single anchoring portion or a plurality of disjoint anchoring portions. In the case of a single anchoring portion, the first and second end walls of said single anchorage portion are separated from each other by a flank portion. In the case of a plurality of disjoint anchorage portions, the first and second end walls of a given anchorage portion are separated from at least one adjacent anchorage portion by a flank portion.

[0018] According to a preferred variant of the second embodiment, the anchoring means comprises at least two disjoint anchoring portions.

[0019] A plurality of anchoring portions allows for anchoring portions with smaller average circumferential lengths, measured along their average circumferential lines, than in the case of a single anchoring portion, thus making them easier to mount. Furthermore, a plurality of anchoring portions allows for greater customization of the side panel design, with the possibility of differentiating the corresponding insert portions intended to cooperate with the anchoring portions.

[0020] According to an even more preferred variant, the at least two disjoint anchoring portions are distributed circumferentially along the same average line.

[0021] This even more preferred variant allows for the standardization of the manufacturing of the circumferentially distributed tire curing mold elements, since the anchor portions to be molded are always positioned on the same radius relative to the axis of rotation. Furthermore, the visual effect of the sidewall insert positioned on the same circumference is frequently desired.

[0022] However, the anchoring portions have their respective average circumferential lines not necessarily positioned on the same circumference, and can therefore be offset from each other in the height of the flank.

[0023] According to a first configuration of the ends of the anchor portion, the first and second end walls of at least one anchor portion are in direct interface with the protrusion of said anchor portion. In other words, the protrusion is extended to the end walls, such that there is continuity between the protrusion and the end walls.

[0024] According to a second configuration of the ends of the anchor portion, the first and second end walls of at least one anchor portion are separated from the protrusion of said anchor portion by an end discontinuity.

[0025] This end discontinuity allows for easier mounting of the opposite insert portion, in particular when the latter includes an additional end fixing means intended to cooperate with said end discontinuity.

[0026] Advantageously the depth Pc of the hollow is at least equal to 3 mm.

[0027] The recess allows the side insert to be anchored in the sidewall by locking the edges of the side insert between the walls of the recess. It therefore helps to hold the side insert in place during rolling, preventing it from being ejected. It also allows the side insert to be engaged within the thickness of the sidewall, so as not to create a significant protrusion. compared to the outer face of the side panel, and therefore not to disrupt the airflow near the side panel in this area. Consequently, the vehicle's aerodynamic drag is not increased. Correspondingly, the vehicle's drag coefficient is not affected, and therefore fuel consumption is not increased.

[0028] According to the invention, the depth Pc of the groove is at least 2 mm. If the depth Pc is less than 2 mm, the anchoring means does not guarantee sufficient grip of the sidewall insert to withstand the various mechanical stresses applied to the tire during its use, throughout its entire lifespan. A minimum groove depth Pc of 3 mm further improves the retention of the sidewall insert in its anchoring means during the various rolling stresses of the tire, and engages the sidewall insert even more deeply in the sidewall, which further reduces aerodynamic drag and, consequently, rolling resistance.

[0029] Even more advantageously the depth Pc of the hollow is at most equal to 7 mm, and preferably at most equal to 5 mm.

[0030] If the groove depth Pc exceeds 7 mm, the thickness of the rubber material layer inside the groove bottom is insufficient to guarantee mechanical decoupling between the sidewall insert, intended to be engaged in said groove, and the outermost tire reinforcement layer. This results in stress concentrations at the bottom of the groove, which can generate cracking and reduce the sidewall's durability. Furthermore, with regard to manufacturing, a groove of limited depth ensures the presence of a sufficient thickness of rubber material layer inside the groove bottom, despite significant material movement in this area during the tire manufacturing and finishing stages. In other words, a moderate groove depth helps guarantee manufacturing tolerances.

[0031] Also advantageously the difference between the thickness W of the outer layer of the flank and the depth Pc of the hollow is at least equal to 1 mm, preferably at least equal to 2 mm.

[0032] The thickness W is measured between the outer face of the sidewall and the reinforcements of the outermost reinforcing layer: it therefore takes into account the outer sidewall layer itself and the outer rubber coating layer of the outermost reinforcing layer. The difference between the thickness W of the outer sidewall layer and the depth Pc of the cavity thus defines the thickness of the layer of rubber material, located between the bottom of the cavity and the outermost reinforcing layer.

[0033] A thickness of 1 mm is the minimum thickness of the rubber material layer, ensuring mechanical decoupling between the side insert, intended to be engaged in said hollow, and the outermost reinforcing layer. This minimum thickness therefore avoids stress concentrations at the bottom of the hollow, which could generate cracking and a reduction in the strength of the flank.

[0034] Advantageously the width Le of the hollow is at most equal to 10% of the nominal section height H of the tire.

[0035] Even more advantageously the width Le of the hollow is at most equal to 20 mm, preferably at most equal to 12 mm.

[0036] The width Le of the groove must remain limited, because the larger it is, the greater the deflection of the sidewall insert area during use, which generates significant deformations and potential fatigue problems of the sidewall insert. Deformations at the groove increase with the width Le of the groove, 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 standard tire specifications, such as, for example, the European Tyre and Rim Technical Organisation (ETRTO) standard.

[0037] Advantageously the protuberance has, in any meridian plane, a height Hp at least equal to the depth Pc of the hollow less 2 mm.

[0038] The protuberance, formed in the hollow from the bottom of the hollow, is intended to come into contact with an inner face of the side insert, and allows the side insert to be supported.

[0039] A minimum height value Hp, equal to the depth Pc of the recess minus 2 mm, allows a side insert to be positioned on the protrusion with sufficient bearing height while not protruding, or only slightly protruding, beyond the outer face of the side. This configuration thus provides effective support for the side insert while protecting it from potential scraping of the side against the curbs. Furthermore, limited engagement of the side insert within the thickness of the side ensures its visibility as a design feature.

[0040] Even more advantageously the protuberance has, in any meridian plane, a height Hp at most equal to the depth Pc of the hollow plus 2 mm.

[0041] A maximum height value Hp, equal to the depth Pc of the groove plus 2 mm, prevents the insert from protruding beyond the outer face of the sidewall. This configuration thus avoids disrupting the airflow near the sidewall in this area. Consequently, the aerodynamic drag of the tire is not increased. As a result, the vehicle's rolling resistance, and therefore fuel consumption, is not increased. Furthermore, the susceptibility of the sidewall to potential sidewall scraping against curbs remains limited.

[0042] According to a particular embodiment of the protrusion, the protrusion is formed, in any meridional plane, by a stepped arrangement of a first narrow portion extending outwards from the bottom of the groove, and a second wide portion extending outwards from the first narrow portion. Such a protrusion thus has a substantially mushroom-like shape, the base of which is the first narrow portion and the head of the second wide portion, which gives it, in addition to its support function, an anchoring function. This mushroom-shaped protrusion configuration allows for effective clipping of the sidewall insert onto said protrusion and ensures that it remains in position during rolling, under the mechanical stresses of bending and centrifugal force applied to the tire.

[0043] The outer sidewall layer in which the cavity is formed extends from an outer sidewall face, in contact with atmospheric air, to an outermost reinforcing layer, most often made of textile reinforcements. More precisely, the outer sidewall layer is in internal contact with the rubber compound encasing the reinforcements of the outermost reinforcing layer, commonly called the coating compound.

[0044] Advantageously, the hollow is formed in an outer flank layer made of a single rubbery material. Consequently, the hollow is not generally formed in a composite layer, made up of a superposition of materials, and therefore potentially susceptible to problems of mechanical strength at the interfaces between said materials.

[0045] Advantageously the circumferential mean line of any anchorage portion is positioned, in any meridian plane, at a radial distance d of at least 5%, preferably at least 10% of the height of the nominal section H of the tire, radially inside an axial line passing at mid-height H / 2 of the nominal section of the tire.

[0046] In particular, for tires whose outermost axial point, on the outer sidewall face, is positioned on the axial line passing through mid-height H / 2 of the nominal tire section, such a positioning of the average circumferential line of any anchoring portion makes it possible to avoid damage to the sidewall insert, in particular during sidewall scraping against a curb,

[0047] The invention also relates to a sidewall insert intended to be mounted on a tire sidewall.

[0048] The sidewall insert includes at least one insert portion intended to cooperate with an anchoring portion of a tire anchoring means according to one of the tire embodiments previously described, by engaging at least one insert portion in the hollow of the corresponding anchoring portion and by bearing said insert portion on the protrusion of said anchoring portion. The ends of any insert portion coincide with the ends of the corresponding anchor portion. In other words, any insert portion and its opposite anchor portion have equal average curvilinear lengths.

[0049] Like the anchoring means, the sidewall insert can be continuous or discontinuous. A continuous insert, intended to cooperate with the first embodiment of the tire described above, forms a complete ring when placed on the sidewall. A discontinuous insert, intended to cooperate with the second embodiment of the tire described above, comprises at least one circumferentially delimited insert portion intended to cooperate with an anchoring portion also circumferentially delimited by a first end wall and a second end wall. In other words, in this case, the sidewall insert comprises either a single insert portion intended to cooperate with a single anchoring portion, or a plurality of insert portions intended to cooperate with a plurality of disjoint anchoring portions.

[0050] According to a preferred embodiment, the side insert comprising at least one insert portion includes additional fastening means intended to cooperate with discontinuities between two consecutive protrusion portions of the anchoring portion or between a protrusion portion and an end wall. These additional fastening means are, for example, pins intended to be driven into the discontinuities.

[0051] According to a particular embodiment, the insert portion may have a variable width in the vicinity of the outer face of the side. This implies a variable hollow width of the opposite anchoring portion.

[0052] Preferably the side insert comprises at least one polymeric material. This polymeric material can be chosen from a rubbery material, a silicone or a thermoplastic material, for example a polyurethane.

[0053] The material(s) constituting the sidewall insert must be sufficiently deformable so as not to generate excessive stresses at the interface between the sidewall insert and the anchoring means, which could induce cracking and fatigue failures in the tire sidewall. A polymeric material, such as, but not limited to, a rubbery material, silicone, or a thermoplastic material, for example, polyurethane, meets this requirement.

[0054] The side insert being made of a material having a modulus of elasticity in tension at 10% elongation M2 and being intended to cooperate with an anchoring means made of a rubbery material having a modulus of elasticity in tension at 10% elongation M1, M2 is advantageously at least equal to 0.4*M1. The side insert must be sufficiently rigid to allow its placement on the side.

[0055] The sidewall insert being made of a material having a tensile modulus of elasticity at 10% elongation M2 and being intended to cooperate with an anchoring means made of a rubbery material having a tensile modulus of elasticity at 10% elongation M1, M2 is advantageously at most equal to 5*M1. The sidewall insert must not be too rigid so as not to generate excessive stresses in the tire sidewall likely to damage the sidewall when it is subjected to bending stresses, and to reduce the risk of ejection by centrifugal force of the sidewall insert during rolling.

[0056] Advantageously, the sidewall insert has a different color and / or texture from the sidewall comprising the anchoring means. Since the objective of the invention is to personalize the design of tire sidewalls, the sidewall insert preferably has a different color and / or texture compared to the sidewall.

[0057] The preferably colored side insert may have one or more colors different from the usual black color of the side. Preferably, the side insert is monochrome for the purpose of simplifying its manufacture.

[0058] According to particular embodiment variants, to differentiate it further from the side, the side insert is covered with a graphic or a texture, for example of a velvet type.

[0059] In the case where the side insert comprises a plurality of insert portions, these advantageously have different colours and / or textures differentiated from each other, with a view to even more specific personalisation.

[0060] The invention finally relates to an assembly consisting 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.

[0061] The features of the invention are illustrated by schematic figures 1 to 9, which are not shown to scale: -[Fig.1]: Meridional half-section of a tire according to the invention, not equipped with a sidewall insert and mounted on its rim, -[Fig.2]: Meridian section of an anchoring means according to the invention, -[Fig.3]: Side view of a portion of a tire according to a first embodiment of a tire according to the invention, not equipped with a sidewall insert, -[Fig.4]: Side view of a portion of a tire according to a first variant of a second embodiment of a tire according to the invention, not equipped with a sidewall insert, -[Fig.5]: Side view of a portion of a tire according to a second variant of the second embodiment of a tire according to the invention, not equipped with a sidewall insert, -[Fig.6]: Side view of the respective ends of two consecutive anchoring portions of a tire according to the second variant of the second embodiment of a tire according to the invention, not equipped with a sidewall insert, -[Fig.7]: Meridional half-section of a tire according to the invention, equipped with a sidewall insert and mounted on its rim, -[Fig.8]: Meridian section of an assembly of a flank insert on its anchoring means according to the invention, -[Fig.9]: Side view of a portion of a tire according to the first variant of the second embodiment of a tire according to the invention, equipped with a discontinuous sidewall insert, -[Fig. 10]: Cross-sectional view of a portion of a tire according to the first variant of the second embodiment of a tire according to the invention, equipped with a discontinuous sidewall insert. -[Fig. 11]: Side view of a portion of a tire according to a first configuration of the second variant of the second embodiment of a tire according to the invention, equipped with a discontinuous sidewall insert, -[Fig. 12]: Cross-sectional view of a portion of a tire according to the first configuration of the second variant of the second embodiment of a tire according to the invention, equipped with a discontinuous sidewall insert. -[Fig. 13]: Side view of a portion of a tire according to a second configuration of the second variant of the second embodiment of a tire according to the invention, equipped with a discontinuous sidewall insert, -[Fig. 14]: Cross-sectional view of a portion of a tire according to the second configuration of the second variant of the second embodiment of a tire according to the invention, equipped with a discontinuous sidewall insert.

[0062] Figure 1 is a meridional half-section of a tire 1 according to the invention, not equipped with a sidewall insert and mounted on its rim 2. The tire 1 for a light vehicle is mounted on a rim 2 and is suitable for being equipped with at least one sidewall insert 9 (not shown) by means of an anchoring means 6. The tire 1 has a nominal section height H as defined by the ETRTO (European Tyre and Rim Technical Organisation) standard and comprises two sidewalls 3 connecting a vertex 4 respectively to two beads 5, each intended to come into contact with the rim 2. The sidewall 3 shown includes an anchoring means 6, intended to cooperate with a sidewall insert 9 (not shown). The anchoring means 6 extends circumferentially, along a circumferential direction XX' of the tire, and includes a hollow 7 formed in an outer layer of sidewall 30 comprising at least one rubbery material, extending from an outer face of sidewall 31 towards the interior of sidewall 3. The anchoring means 6 includes a protrusion 8, raised relative to the bottom of the hollow and extending from the bottom of the hollow to the vicinity of the outer face of sidewall 31. In addition, the circumferential mean line of the anchoring means 6 is positioned, in the meridian plane YZ, at a radial distance d of at least 5%, preferably at least 10% of the height of the nominal section H of the tire 1, radially inside an axial line D passing through a point P on the outer face of sidewall 31, at mid-height H / 2 of the nominal section of the tire 1, and perpendicular to the equatorial plane XZ of the tire 1.

[0063] The [Fig.2] is a meridian section of an anchoring means 6 according to the invention. This is a detailed view of [Fig. 1]. The anchoring means 6 comprises a recess 7 and a protrusion 8. The recess 7 is delimited internally by a recess bottom 71 and radially delimited by a radially inner circumferential wall 72, closest to the axis of rotation of the tire, and by a radially outer circumferential wall 73, furthest from the axis of rotation of the tire. The recess 7 has, in the meridian plane YZ containing the axis of rotation YY' of the tire, a depth Pc, the maximum distance measured perpendicularly between the outer face of the sidewall 31 and the recess bottom 71, and a width Le, measured at the level of the outer face of the sidewall 31, along a line perpendicular to the two radially inner circumferential walls 72 and radially outer circumferential walls 73, respectively. The depth Pc of the recess 7 is at least 2 mm and at most 7 mm.The width Le of the groove 7 is at most equal to 25%, preferably at most equal to 15%, and even more preferably at most equal to 10% of the nominal section height H of the tire 1. The outer sidewall layer 30 having a thickness W at the anchoring means 6, the difference between the thickness W of the outer sidewall layer 30 and the depth Pc of the groove 7 is at least equal to 1 mm. Furthermore, in the embodiment shown, the protrusion 8, having a height Hp, is formed, in any meridian plane YZ, by a stepped arrangement of a first narrow portion extending outwards from the bottom of the groove 71, and a second wide portion extending outwards from the first narrow portion, which gives it a mushroom shape.

[0064] Figure 3 is a side view of a portion of a tire 1 according to a first embodiment of a tire according to the invention, not equipped with a sidewall insert. The sidewall 3 extends between the apex 4 and the bead 5. The first embodiment is characterized by an anchoring means 6 comprising a single anchoring portion continuous over the entire circumference, forming a complete ring on the sidewall of the tire. The anchoring means 6 comprises a recess 7, formed in an outer layer of the sidewall, and a protrusion 8, raised above the bottom of the recess and extending from the bottom of the recess to the vicinity of the outer face of the sidewall. According to the invention, the protrusion 8 comprises a plurality of disjointed protrusion portions 81 distributed circumferentially along the circumferential mean line of the anchoring means 6.

[0065] Figure 4 is a side view of a portion of a tire 1 according to a first embodiment of a second embodiment of a tire according to the invention, not equipped with a sidewall insert. The second embodiment shown is characterized by an anchoring means 6 comprising a plurality of disjointed anchoring portions 61, distributed circumferentially along the same circumferential mean line. Each anchoring portion 61 is circumferentially delimited by a first end wall 74 and by a second end wall 75. In addition, each anchoring portion 61 comprises a recess 7, formed in an outer sidewall layer, and a protrusion 8, projecting from the bottom of the recess and extending from the bottom of the recess to the vicinity of the outer sidewall face.According to the invention, the protrusion 8 of any anchor portion comprises a plurality of disjointed protrusion portions 81 distributed circumferentially along the circumferential mean line of the anchor portion 61. The first variant of this second embodiment is characterized by first and second end walls (74, 75) of each anchor portion 61 in direct interface with the protrusion 8 of said anchor portion 61. In other words, in this first variant, the protrusion 8 is extended to the end walls (74, 75), such that there is continuity between the protrusion 8 and the end walls (74, 75).

[0066] Figure 5 is a side view of a portion of a tire 1 according to a second variant of the second embodiment of a tire according to the invention, not equipped with a sidewall insert. This second variant of the second embodiment differs from the first variant of the second embodiment, previously described in Figure 4, in that the first and second end walls (74, 75) of each anchoring portion 61 are separated from the protrusion 8 of said anchoring portion 61 by an end discontinuity 76.

[0067] Fig. 6 is a side view of the respective ends of two consecutive anchoring portions 61 of a tire 1 according to the second variant of the second embodiment, illustrated in Fig. 5, of a tire according to the invention, in which the first and second end walls (74, 75) of each anchoring portion 61 are separated from the protrusion 8 of said anchoring portion 61 by an end discontinuity 76.

[0068] Fig. 7 is a meridional half-section of a tire 1 according to the invention mounted on its rim 2 and equipped with a sidewall insert 9. It combines the tire of Fig. 1 with a sidewall insert 9. The common references in Figures 7 and 1 designate the same elements.

[0069] Figure 8 is a meridional cross-section of an assembly of a flank insert 9 on its anchoring means 6 according to the invention. It is a detailed view of Figure 7. The common reference numerals in Figures 8 and 2 designate the same elements.

[0070] Figure 9 is a side view of a portion of a tire 1 according to the first variant of the second embodiment, as shown in Figure 4, the tire being equipped with a discontinuous sidewall insert 9. The sidewall insert 9 comprises a plurality of insert portions 91 which cooperate with a plurality of anchoring portions 61, as shown in Figure 4. Each insert portion 91 cooperates with an anchoring portion 61 by engaging said insert portion 91 in the recess 7 of the corresponding anchoring portion 61 and by bearing said insert portion 91 on the protrusion 8 of said anchoring portion 61. In addition, each insert portion 91 comprises complementary fastening means 92, of the pin type, which cooperate with the discontinuities between two consecutive protrusion portions 81 of the anchoring portion 61.More specifically, these additional fixation means 92 are inserted into the discontinuities between two consecutive disjoint portions of protuberance.

[0071] Fig. 10 is a cross-sectional view of a portion of a tire 1 according to the first variant of the second embodiment of a tire according to the invention, as shown in Fig. 9. More precisely, it is a cross-section of Fig. 9 along the average line of the anchoring portion.

[0072] The [Fig. 11] is a side view of a portion of a tire 1 according to a first configuration of the second variant of the second embodiment of a tire according to the invention, as shown in the [Fig. 5], the tire being equipped with a discontinuous sidewall insert 9. The side insert 9 comprises a plurality of insert portions 91 which cooperate with a plurality of anchoring portions 61, as shown in Figures 5 and 6. Each insert portion 91 cooperates with an anchoring portion 61 by engaging said insert portion 91 in the recess 7 of the corresponding anchoring portion 61 and by bearing said insert portion 91 on the protrusion 8 of said anchoring portion 61. In addition, each insert portion 91 comprises complementary fastening means 92, of the pin type, which cooperate with the discontinuities between two consecutive protrusion portions 81 of the anchoring portion 61.More specifically, these additional fixation means 92 are embedded in the discontinuities between two consecutive disjoint protrusion portions. This first configuration is characterized by an insert portion. 91 not including additional fixing means 92 at the end and therefore not cooperating with end discontinuities 76.

[0073] Fig. 12 is a cross-sectional view of a portion of a tire according to the first configuration of the second variant of the second embodiment of a tire according to the invention, as shown in Fig. 11. More precisely, it is a cross-section of Fig. 11 along the mean line of the anchoring portion.

[0074] Fig. 13 is a side view of a portion of a tire 1 according to a second configuration of the second variant of the second embodiment of a tire according to the invention, as shown in Fig. 5, the tire being equipped with a discontinuous sidewall insert 9. This second configuration differs from the first configuration, illustrated in Figures 11 and 12, in that each portion of the insert 91 includes additional end-fixing means 92 which cooperate with the end discontinuities 76.

[0075] Fig. 14 is a cross-sectional view of a portion of a tire according to the second configuration of the second variant of the second embodiment of a tire according to the invention, as shown in Fig. 13. More precisely, it is a cross-section of Fig. 13 along the middle line of the anchoring portion.

[0076] The inventors have more particularly studied this invention for 3 types of tires: a PI tire of size 255 / 35 ZR 20, a P2 tire of size 275 / 35 ZR 21 and a P3 tire of size 305 / 30 ZR 21.

[0077] The characteristics of the three tire examples studied by the inventors are presented in Table 1 below: [Tables 1] Specifications Pneumatic PI Pneumatic P2 Pneumatic P3 Nominal cross-section H of the pneumatic 89.3 mm 96.3 mm 91.5 mm Radial distance d of the anchoring means at mid-height H / 2 of nominal cross-section 14.0 mm 16.6 mm 12.9 mm Depth Pc of the hollow 4.2 mm 4.2 mm 4.2 mm Width Le of the hollow 9.0 mm 9.0 mm 9.0 mm Height Hp of the protrusion 3.0 mm 3.0 mm 3.0 mm Curvilinear distance De of an anchoring portion 218.0 mm 258.0 mm 263.0 mm Number of anchoring portions 7 5 5 Number of protrusions per anchor segment (if anchoring method is discontinuous) Between 2 and 8 Between 2 and 8 Between 2 and 8 Total number of protrusions per anchor segment (if anchoring method is continuous around the entire circumference) 23 23 23 Circumferential length of a protrusion Between 20 mm and 80 mm Between 20 mm and 80 mm Between 20 mm and 80 mm Distance between two consecutive protrusions (= width of discontinuities) Between 3 and 4 mm Between 3 and 4 mm Between 3 and 4 mm

[0078] The inventors were able to observe an easy assembly and a satisfactory and lasting attachment to the sidewall during rolling, for a sidewall insert equipping a sidewall of a tire according to the invention.

Claims

1. Demands Tyre (1) for a light vehicle, intended to be mounted on a rim (2) and suitable for being fitted with at least one sidewall insert (9), said tyre (1), having a nominal section of height H and an axis of rotation defining an axial direction (YY'), and comprising: -two sidewalls (3) connecting a vertex (4) respectively to two beads (5), each intended to come into contact with the rim (2), -at least one sidewall (3) comprising an anchoring means (6), intended to cooperate with a sidewall insert (9), -the anchoring means (6) comprising at least one anchoring portion (61) having a circumferential mean line (Lm) extending in a circumferential direction (XX'), -at least one anchoring portion (61) comprising a hollow (7), formed in an outer flank layer (30), in contact with atmospheric air, said outer flank layer (30) comprising at least one rubbery material and extending from an outer flank face (31) towards the interior of the flank (3), -the hollow (7) having a hollow bottom (71) and being delimited by a radially inner circumferential wall (72), closest to the axis of rotation of the tire, and by a radially outer circumferential wall (73), furthest from the axis of rotation of the tire, -the hollow (7) having, in any meridian plane (YZ) containing the axis of rotation of the tire, a depth Pc, maximum distance measured perpendicularly between the outer face of the sidewall (31) and the bottom of the hollow (71), at least equal to 2 mm, and a width Le, measured at the level of the outer face of the sidewall (31), along a line perpendicular to the two circumferential walls respectively radially inner (72) and radially outer (73), at most equal to 15% of the nominal section height H of the tire (1), -at least one anchoring portion (61) further comprising a protrusion (8), raised above the bottom of the hollow (71) and extending from the bottom of the hollow (71) to the vicinity of the outer face of the flank (31), characterized in that the protrusion (8) of any anchoring portion (61) comprises at least two protrusion portions (81) disjoint and distributed circumferentially along the circumferential mean line (Lm) of the anchoring portion (61).

2. Pneumatic (1) according to claim 1, wherein the anchoring means (6) comprises a single anchoring portion (61) continuous over the entire circumference.

3. Pneumatic (1) according to claim 1, wherein at least one anchoring portion (61) is circumferentially delimited by a first end wall (74) and by a second end wall (75).

4. Pneumatic (1) according to any one of claims 1 or 3, wherein the anchoring means (6) comprises at least two disjoint anchoring portions (61).

5. Pneumatic (1) according to claim 4, wherein the at least two disjoint anchoring portions (61) are distributed circumferentially along the same mean line (Lm).

6. Pneumatic (1) according to any one of claims 3 to 5, wherein the first and second end walls (74, 75) of at least one anchoring portion (61) are in direct interface with the protrusion (8) of said anchoring portion (61).

7. Pneumatic (1) according to any one of claims 3 to 5, wherein the first and second end walls (74, 75) of at least one anchor portion (61) are separated from the protrusion (8) of said anchor portion (61) by an end discontinuity (76).

8. Pneumatic (1) according to any one of claims 1 to 7, wherein the depth Pc of the hollow (7) is at least equal to 3 mm.

9. Pneumatic (1) according to any one of claims 1 to 8, wherein the depth Pc of the hollow (7) is at most equal to 7 mm, and preferably at most equal to 5 mm.

10. Pneumatic (1) according to any one of claims 1 to 9, the outer sidewall layer (30) having a thickness W at the anchoring means (6), wherein the difference between the thickness W of the outer sidewall layer (30) and the depth Pc of the hollow (7) is at least equal to 1 mm, preferably at least equal to 2 mm.

11. Tire (1) according to any one of claims 1 to 10, wherein the width Le of the hollow (7) is at most equal to 10% of the nominal section height H of the tire (1).

12. Pneumatic (1) according to any one of claims 1 to 11, wherein the width Le of the hollow (7) is at most equal to 20 mm, preferably at most equal to 12 mm.

13. Pneumatic (1) according to any one of claims 1 to 12, wherein the protrusion (8) has, in any meridian plane (YZ), a height Hp at least equal to the depth Pc of the hollow (7) less 2 mm.

14. Pneumatic (1) according to any one of claims 1 to 13, wherein the protrusion (8) has, in any meridian plane (YZ), a height Hp at most equal to the depth Pc of the hollow (7) plus 2 mm.

15. Pneumatic (1) according to any one of claims 1 to 14, wherein the protrusion (8) is constituted, in any meridian plane (YZ), by a staggered arrangement of a first narrow portion extending outwards from the bottom of the hollow (71), and a second wide portion extending outwards from the first narrow portion.

16. Sidewall insert (9) comprising at least one insert portion (91) intended to cooperate with an anchoring portion (61) of an anchoring means (6) of a tire (1) according to any one of claims 1 to 15, by engaging at least one insert portion (91) in the hollow (7) of the corresponding anchoring portion (61) and by bearing said insert portion (91) on the protrusion (8) of said anchoring portion (61).

17. Side insert (9) according to claim 16 comprising at least one insert portion (91) comprising additional fastening means (92), intended to cooperate with discontinuities between two consecutive protrusion portions (81) of the anchoring portion (61) or between a protrusion portion (81) and an end wall (74, 75).

18. Side insert (9) according to any one of claims 16 or 17 comprising at least one polymeric material.

19. Side insert (9) according to any one of claims 16 to 18 having a colour and / or texture different from that of the side (3) comprising at least one anchoring means (6).

20. Side insert (9) according to any one of claims 16 to 19 comprising a plurality of insert portions (91) having different colours and / or textures differentiated between said insert portions (91). 20

21. Assembly (10) consisting of a tire (1) according to any one of claims 1 to 15 and at least one sidewall insert (9) according to any one of claims 16 to 20.

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