Tire including a sidewall insert

Abstract

The present invention relates to a tire (1) for a light vehicle, suitable for being fitted with a sidewall insert (9), said tire (1) comprising a protective bead (32) having an edge (321), the edge being the outermost axial area of ​​the sidewall, the measurement being taken on the tire mounted on a rim (2) at a pressure of 2 bar. The sidewall (3) comprises an anchoring means (6), having a circumferential mean line (61), intended to cooperate with at least the sidewall insert (9). The circumferential mean line (61) of the anchoring means (6) is positioned radially inside the edge (321) of the protective bead (32). Fig. 1

Description

Title of the invention: Tire comprising a sidewall insert

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

[0002] A constant 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] Since a tire has a geometry of revolution about an axis of rotation, the tire's geometry is generally described in a meridian plane containing the tire's axis of rotation. For a given meridian plane, the radial, axial, and circumferential directions respectively denote the directions perpendicular to the tire's axis of rotation, parallel to the tire's axis of rotation, and perpendicular to the meridian plane. The circumferential direction is tangent to the tire's circumference.

[0004] In what follows, the expressions "radially inside" and "radially outside" respectively mean "closer to" and "farthest from" the axis of rotation of the tire. "Axially inside" and "axially outside" respectively mean "closer to" and "farthest from" the equatorial plane of the tire, the equatorial plane of the tire being the plane passing through the midpoint of the tread and perpendicular to the axis of rotation. "An element A axially inside an element B by an axial distance D" means that element A is closer to the equatorial plane than element B and that the axial distance between the two elements is equal to the distance D. This type of sentence can be generalized to the radial and circumferential direction and the outside versus inside position of either element.

[0005] Generally, a tire comprises a tread, intended to come into contact with a ground by means of a tread surface, the two axial ends of which are connected by means of two sidewalls to two beads ensuring the mechanical connection between the tire and the rim on which it is intended to be mounted.

[0006] By "bead" of a tire, we mean a part of the tire intended to sit on a wheel rim.

[0007] A radial tire further comprises a reinforcing reinforcement, consisting of a crown reinforcement, radially inside the tread, and a carcass reinforcement, radially inside the crown reinforcement.

[0008] A known method for customizing the sidewall of a tire is a colored rubber compound, for example, white, contained within the tire sidewall 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 compound 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.

[0009] Document WO2022 / 069832 A1 describes an insert in the form of a tire lining element designed to be removably inserted into a sidewall. The lining element is positioned radially, specifically outside the edge of the protective cord. However, this lining element is susceptible to deformation and detachment from the sidewall, particularly during impacts with curbs or when cornering under high lateral thrust. Furthermore, such an insert causes significantly detrimental aerodynamic drag at high speeds, namely above 120 km / h. The tires most specifically concerned by this type of insert are luxury sports car tires with a speed rating of at least S (180 km / h).

[0010] The inventors have set themselves the objective of proposing a tire suitable for being equipped with at least one sidewall insert, with an improved mounting and attachment to the sidewall resistant to shocks and curb scrapes and to cornering with high transverse thrust and significantly reducing the aerodynamic drag of the insert.

[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 comprising: -two sides connecting a vertex to two ridges, each designed to come into contact with the rim, - at least one sidewall comprising, on its axially outer face of the sidewall, a protective bead having an edge, being the most axially outer area of ​​the sidewall, the measurement being taken on the tire mounted on a rim at a pressure of 2 bar, -at least one side comprising an anchoring means, intended to cooperate with at least one side insert, - the anchoring means extending circumferentially, along a circumferential direction (XX') of the tire, and comprising at least one hollow formed in an axially outer layer of the sidewall comprising at least one rubbery material, said hollow extending from an axially outer face of the sidewall axially towards the interior of the sidewall, - the anchoring means having a circumferential mean line, - the circumferential mean line of the anchoring means being positioned radially inside the edge of the protective cord.

[0012] The principle of the invention is to have an anchoring means for a flank insert comprising at least one circumferential cavity formed in an axially outermost layer of the flank. A cavity always comprises at least two walls connected by a bottom surface. A circumferential cavity on the flank comprises at least one outermost radially circumferential wall and one innermost radially circumferential wall. Therefore, the anchoring means comprises at least one outermost radially circumferential wall and one innermost radially circumferential wall, both of which may or may not belong to the same cavity.

[0013] The anchoring means may include a protrusion, formed in said hollow or between two hollows to improve the mechanical strength of the insert, particularly during rolling, or to improve the positioning of the insert, particularly centering at the time of insert assembly.

[0014] The tire according to the invention also includes a sidewall protection bead to protect the carcass against impacts or abrasions on the sidewall, particularly impacts against curbs. The protection bead is therefore the outermost axial area of ​​the tire. It consists of a circumferential axial overthickness of rubber, sometimes pyramidal, with a maximum radial thickness of approximately 5 mm over a radial height of 15 mm. A protection bead may have a variable axial overthickness of rubber around its circumference, with bumps, grooves, or any other pattern. The overthickness is evaluated by considering, for the tire sidewall, the difference between the local distance between the innermost axial layer of the carcass and the outer surface—that is, the surface in contact with the outside air—of the sidewall, and the average of this distance.At the level of the protective bead, this difference in thickness increases and then decreases over a radial height of approximately 10 mm to 15 mm from the height of the sidewall, with an axial thickness of approximately 2 to 5 mm. The edge of the protective bead is not necessarily protruding; the bead may be chamfered or rounded. measurements of the distances between the outermost axial layer of carcass and the external surface of the flank will be taken on a meridional section.

[0015] The anchoring means, i.e., the groove, can be circumferentially continuous or circumferentially discontinuous, that is, formed of circumferential portions disjointed from one another. The mean circumferential line of the anchoring means is located at the mean radius between the radius of the outermost radially outer circumferential wall and the radius of the innermost radially inner circumferential wall at their junctions with the outer surface of the sidewall. If a fillet exists at the junctions between said surfaces, the radius of each circumferential wall will be considered to be radially equidistant from the two ends of the fillet in question. In the case of a discontinuous groove, the calculation of the mean circumferential line of the groove will be performed on the portions of the tire in which a groove is present.

[0016] The hollow also allows the side insert to be engaged in the thickness of the side, so as not to create a significant protrusion in relation to the axially external face of the side, and therefore not to disturb the airflow in the vicinity of the side in this area.

[0017] The principle of the invention is that, contrary to the state of the art, the anchoring means suitable for receiving an insert is radially inside the protective cord because, unexpectedly, this position protects the insert much better from being pulled out, among other advantages of the invention.

[0018] The axially outermost flank layer in which the anchoring means is formed extends axially from an axially outermost flank face, in contact with atmospheric air, to a most axially outermost reinforcing layer, most often made of textile reinforcements. More precisely, the axially outermost flank layer is in axially inner contact with the rubber compound encasing the reinforcements of the most axially outermost reinforcing layer, commonly called the coating compound.

[0019] The hollow allows the insert to be anchored in the side panel by locking the edges of the side panel insert between its walls. It therefore contributes to holding the side panel insert in place, preventing it from being ejected during rolling.

[0020] According to the invention, a preferred solution is that, for the tire intended to be mounted on a rim of diameter D in mm, in any meridian plane (YZ), the circumferential mean line of the anchoring means is positioned at a diameter DI of at least D+44 mm and at most D+80 mm, preferably at most D+70 mm. The insert is positioned in the most optimal area of ​​the sidewall between the rim and the protective bead.

[0021] According to one embodiment of the invention, the edge of the protective cord is at a radial distance from the circumferential mean line of the anchoring means of at least 4 mm in order to optimize the protective effect of the protective cord with respect to the insert against curb impacts in particular.

[0022] For optimization of the effect of the insert with respect to the tire, it is advantageous that the edge of the protective cord be positioned at a diameter D2 of at least equal to D+52 mm and at most equal to D+96 mm, preferably at most equal to D+86 mm.

[0023] Furthermore, such a position of the anchoring means reduces its potential wear due to friction between the insert and the walls of the groove because it is not in the area of ​​greatest sidewall flex. Indeed, during use, the sidewall deforms, particularly as it passes over the contact patch with the ground. This deformation increases from the rim due to the rigidity of the rim and the bead. Since the spokes have different radii and the insert is not an integral part of the tire, the walls of the grooves and the walls of the insert deform differently, creating movement and friction at their contact points, thus causing wear. The recommendations given significantly reduce this phenomenon.The diameter D of a rim is defined by the usual standards relating to tires, such as, for example, the standard of the "European Tyre and Rim Technical Organisation" or "ETRTO" standard.

[0024] A protrusion, formed in the hollow from the bottom of the hollow, designed to come into contact with an axially inner face of the sidewall insert, can allow for better anchoring of the sidewall insert thanks to a specific shape. One solution for such a protrusion is to have a shape substantially resembling a mushroom, the base of which is axially inner to the head, the portion with the greatest radial width. This protrusion configuration allows for effective clipping of the sidewall insert onto the protrusion and ensures that it remains in position during rolling, under the mechanical stresses of bending and centrifugal force applied to the tire.

[0025] A thickness of 1 mm is the minimum thickness of the rubber layer, ensuring mechanical decoupling between the side insert, intended to be engaged in said hollow, and the nearest axially internal reinforcing bar. This minimum thickness prevents stress concentrations at the bottom of the hollow.

[0026] Preferably the hollow is formed in an axially external flank layer made of a single rubbery material.

[0027] Advantageously the hollow is not formed in a composite layer, made up of a superposition of materials, and, therefore, potentially sensitive to problems of mechanical strength of the interfaces between said materials.

[0028] Advantageously the line, contained in any meridian plane and passing through two points of intersection respectively of each wall of cavity with the axially external face of flank, forms, with the radial direction, an angle at most equal to 25°, preferably at most equal to 15°.

[0029] When angle A exceeds 25°, the axially external face of the sidewall becomes too inclined relative to the radial direction in the area of ​​the anchoring means, generally near the tire bead. Consequently, the insert becomes less visible and loses its effectiveness.

[0030] The sidewall insert is intended to cooperate with an anchoring means according to one of the pneumatic embodiments previously described, by engaging in the hollow of the anchoring means and possibly by clipping if the anchoring means is provided with a protrusion.

[0031] If the anchoring means includes a protrusion having an external meridian profile, the flank insert preferably has an internal meridian profile substantially parallel to the external meridian profile of the protrusion. In other words, in this configuration the flank insert has a mushroom shape that constitutes a female portion into which the male mushroom shape of the protrusion fits, thus ensuring secure anchoring.

[0032] According to a preferred embodiment, the side insert comprises at least one polymeric material, such as an elastomeric, rubbery, silicone or thermoplastic material.

[0033] The material(s) constituting the side insert must be sufficiently deformable so as not to generate excessive stresses at the interface between the side insert and the anchoring means, which could induce wear of the insert. A polymeric material, such as, but not limited to, an elastomeric, rubbery, silicone, or thermoplastic material, satisfies this requirement.

[0034] The sidewall insert preferably has a different color and / or texture from that of 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.

[0035] 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. The side insert may be continuous circumferentially or made of pieces.

[0036] According to particular embodiment variants, to differentiate it further from the side, the side insert is covered with a graphic or texture, for example of the microtexture or velvet type, suitable for creating contrast effects, or dyed in the mass.

[0037] Preferably, the tire is asymmetric and preferably non-directional, and includes an anchoring means designed to cooperate with at least one sidewall insert on only one of the tire's two sidewalls. It is not relevant to have a sidewall insert positioned on the inside of the vehicle, as it is not visible. Therefore, it is advantageous to have an anchoring means on only one sidewall of the tire. Since the tire is already asymmetric by virtue of its sidewalls, it is advantageous for this asymmetry to be reflected in the tread pattern, with one side of the tread being positioned, according to the manufacturer's recommendations, on the outside of the vehicle. To avoid having two tires, one for the right side and one for the left side of the vehicle, it is advantageous for the tire to be non-directional.Thus, to maintain the axisymmetry of the tire, it is sufficient to rotate the right tire relative to the left tire on the same axle, so that the right tire is the symmetrical image of the left tire with respect to the plane perpendicular to the axle.

[0038] 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.

[0039] The features of the invention are illustrated by the schematic [Fig.1] and not shown to scale.

[0040] Figure 1 is a meridional half-section of a tire 1 according to the invention mounted on a rim 2 of diameter D and equipped with a sidewall insert 9 clipped into the sidewall 3. The sidewall 3, connecting the apex 4 to the bead 5, comprises, on its axially outer sidewall face 31, a protective cord 32 having an edge 321 positioned at a diameter D2. This edge 321 is the outermost axial area of ​​the sidewall. The sidewall 3 also comprises an anchoring means 6, including at least one recess 7 and intended to cooperate with the sidewall insert 9. The anchoring means 6 has a circumferential centerline 61, having a diameter DI. The circumferential mean line 61 is positioned radially inside the edge 321 of the protective cord 32 and at a radial distance d from the edge 321. The radial distance d is at least equal to 4 mm.The line T passing through the two points of intersection 71 and 72 respectively of each cavity wall with the axially external flank face 31, forms, with the radial direction (ZZ'), an angle A of at most equal to 20°, preferably at most equal to 15°.

[0041] The inventors have more particularly studied this invention for a tire of size 275 / 35 R 21 103 Y XL, intended to be inflated to a recommended pressure of 2.9 bars and to carry a maximum load of 875 kg.

[0042] The tire according to the invention was compared to a prior art control tire. The anchoring means of both tires have the same geometry, as do the inserts, which are clipped onto protrusions. Only the position of the anchoring means relative to the protective cord differs. According to the invention, the mean line of the anchoring means is 7 mm from the edge of the protective cord but radially inside it. In the control tire, the mean line of the anchoring means is 4 mm from the edge of the protective cord but radially outside it.

[0043] Expert knowledge knowing that the position of the insert for the tire according to the invention masks the position of the edge of the insert by that of the cord makes it possible to know with certainty that the aerodynamic drag of the invention will be less than that of the control tire in the majority of vehicles.

[0044] Tests conducted under sporting conditions on a track with sharp turns and maximum lateral forces exceeding 1 g over a distance of 50 km resulted in local disengagement of the anchoring means on the test tire. The same test for the tire according to the invention showed that the insert remained clipped onto the tire according to the invention along its entire length.

[0045] These tests demonstrate the value of the invention.

Claims

Demands

1. A tire (1) for a light vehicle, intended to be mounted on a rim (2) of diameter D in mm and suitable for being fitted with at least one sidewall insert (9), said tire (1) comprising: - two sidewalls (3) connecting a crest (4) respectively to two beads (5), each intended to contact the rim (2), - at least one sidewall (3) comprising, on its axially outer sidewall face (31), a protective bead (32) having an edge (321), being the most axially outer area of ​​the sidewall, the measurement being taken on the tire mounted on a rim (2) at a pressure of 2 bar, - at least one sidewall (3) comprising an anchoring means (6) intended to cooperate with at least one sidewall insert (9), - the anchoring means (6) extending circumferentially, in a circumferential direction (XX') of the tire, and comprising at least one recess (7) formed in an axially outer layer of the sidewall (3) comprising at least one rubbery material,said hollow (7) extending from an axially external face of the flank (31) axially towards the interior of the flank (3), - the anchoring means (6) having a circumferential mean line (61), - characterized in that the circumferential mean line (61) of the anchoring means (6) is positioned radially inside the edge (321) of the protective cord (32), in that, in any meridian plane (YZ), the circumferential mean line (61) of the anchoring means (6) is positioned at a diameter DI of at least D+44 mm and at most D+80 mm, in that the edge (321) of the protective cord (32) is at a radial distance (d) from the circumferential mean line (61) of the anchoring means (6) of at least 4 mm, and in that the anchoring means (6) is circumferentially continuous.

2. Pneumatic (1) according to claim 1, wherein, in any meridian plane (YZ), the circumferential mean line (61) of the anchoring means (6) is positioned at a diameter DI not exceeding D+70 mm.

3. A tire (1) according to any one of claims 1 or 2, intended to be mounted on a rim of diameter D in mm in in which the edge (321) of the protective cord (32) is positioned at a diameter D2 of at least D+52 mm and at most D+96 mm, preferably at most D+86 mm.

4. Pneumatic (1) according to any one of claims 1 to 3, wherein a straight line (T), contained in any meridian plane (YZ) and passing through two points of intersection (71, 72) respectively of the outermost radially outer circumferential wall and the innermost radially inner circumferential wall of the hollow (7) with the axially outer sidewall face (31), forms, with the radial direction (ZZ'), an angle (A) at most equal to 20°, preferably at most equal to 15°.

5. A tire (1) according to any one of claims 1 to 4, wherein the tire is asymmetric and preferably non-directional and includes an anchoring means (6) for cooperating with at least one sidewall insert (9) on one of the two sidewalls of the tire.

6. Assembly consisting of a tire (1) according to any one of claims 1 to 5 and at least one sidewall insert (9) intended to cooperate with the anchoring means (6).

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