Tyre comprising a sidewall insert

Abstract

The invention relates to a tyre (1) for a light vehicle, which tyre is intended to be mounted on a rim (2) and provided with at least one sidewall insert (9), comprising an anchoring means (6), extending circumferentially, which comprises a recess (7) formed in the sidewall (30), and comprises a projection (8), in relief with respect to the bottom of the recess (71), the projection (8) consisting of a stepping of a first, narrow portion (81) and a second, wide portion (82) and each sidewall insert (9) engaging with the circumferential anchoring means (6) by insertion into the recess (7) and by clipping onto the projection (8). According to the invention, each sidewall insert (9) engages with the tyre (1) by adhesion, by means of an adhesive, to a total adhered surface made up 100% by a surface adhered to the projection (8) and at least 80% of the total adhered surface is located on the total surface Stpl of the second, wide portion (82) of the projection (8).

Description

Tire including 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 through colored means and / or additional elements, called inserts in this document.

[0003] A tire having a geometry of revolution with respect to an axis of rotation, the geometry of the tire is generally described in a meridian plane containing the axis of rotation of the tire. For a given meridian plane, the radial, axial and circumferential directions respectively designate the directions perpendicular to the axis of rotation of the tire, parallel to the axis of rotation of the tire and perpendicular to the meridian plane. The circumferential direction is tangent to the circumference of the tire.

[0004] In the following, the expressions "radially inward", respectively "radially outward" mean "closer", respectively "further from the axis of rotation of the tire". By "axially inward", respectively "axially outward", is meant "closer", respectively "further from the equatorial plane of the tire", the equatorial plane of the tire being the plane passing through the middle of the rolling surface and perpendicular to the axis of rotation. By "an element A axially inward to an element B by an axial distance D", is meant 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 with the radial and circumferential direction and the outer versus inner position of one or the other of the elements.

[0005] Generally speaking, a tire comprises a tread, intended to come into contact with the ground via a rolling surface, the two axial ends of which are connected via two sidewalls with 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 colored means for personalizing the sidewall of a tire is a colored rubber composition, for example white, contained in the sidewall of the tire and contrasting with the black color of the adjacent rubber compositions. However, this technical solution has a number of disadvantages. First of all, certain chemical components, such as protective components, contained in the rubber compositions adjacent to the colored means, can migrate to the colored rubber composition and cause it to gradually discolor over time. In addition, deformations of the sidewall during the life of the tire can initiate cracks in the colored rubber composition and degrade its appearance. Furthermore, the mechanical means used to mount the tire on its rim, by rubbing on the colored rubber composition, can also degrade it.Finally, the manufacture of a tire comprising portions of differentiated colors is more complex industrially.

[0009] Document WO2022 / 069832 A1 describes an insert in the form of a tire trim element intended to be removably engaged in a sidewall. The trim element is positioned more particularly radially outside the edge of the protective cord. However, this trim element is likely to deform and detach from the sidewall, particularly during impacts against curbs or when cornering with strong transverse thrust causing significant flexing of the sidewall.

[0010] The inventors set themselves the objective of proposing a tire capable of being equipped with at least one sidewall insert, with improved mounting and attachment to the sidewall, resistant to impacts and curb scraping and cornering with strong transverse thrust, this insert being easily replaceable.

[0011] This objective was achieved by a tire for a light vehicle, intended to be mounted on a rim and equipped with at least one sidewall insert, said tire having a nominal section of radial height H and comprising: -two sides connecting a summit respectively to two beads, each intended to come into contact with the rim, -at least one side comprising an anchoring means, intended to cooperate with at least one side insert, -the anchoring means extending continuously or discontinuously in a circumferential direction of the tire, and comprising a hollow formed in the sidewall, extending from an axially outer face of the sidewall axially towards the inside of the sidewall, -the hollow being delimited axially towards the inside by a hollow bottom and radially by two hollow walls, - the anchoring means comprising a protuberance, in relief relative to the bottom of the hollow and extending from the bottom of the hollow to the vicinity of the axially outer face of the flank, - the protuberance being constituted, in a meridian plane, by a step of a first narrow portion extending axially outwards from the bottom of the hollow and having a minimum width equal to the minimum protuberance width Lpmin, and of a second wide portion extending axially outwards from the first narrow portion and having a maximum width equal to a maximum protuberance width Lpmax, at least equal to 1.1 *Lpmin. and a total external surface Stpl, - each sidewall insert cooperating with the anchoring means by engagement in the hollow of the anchoring means and by clipping onto the protuberance of the anchoring means, - each sidewall insert cooperating with the anchoring means by adhesion, by means of an adhesive, on a total bonded surface consisting 100% of a surface bonded to the protuberance, - at least 80% of the total bonded surface being located on the total surface Stpl of the second wide portion of the protuberance.

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

[0013] The anchoring means comprises a protrusion, formed in said hollow to improve the mechanical strength of the insert, in particular during rolling, or to improve the positioning of the insert, in particular the centering when mounting the insert. To assist in the mechanical strength of the insert, the protrusion has a male shape which will cooperate with the insert comprising the corresponding female shape in order to ensure clipping allowing precise centering and a first solution for resisting the mechanical stresses applied to the insert during rolling.This male form is composed of a narrow foot or first narrow portion extending axially outwards from the bottom of the hollow and having a minimum width equal to the minimum protrusion width Lpmin and a blocking or force-recovery excess thickness wider than the foot, called the second portion extending axially outwards from the first narrow portion and having a maximum width equal to a maximum protrusion width Lpmax, at least equal to 1.1 *Lpmin. The foot of the protrusion has an outer surface that is substantially less visible due to the second portion of the protrusion. The second portion widens and ends with an axially outer surface visible from the outside of the tire. This axially outer surface is measured from a meridian section of the tire from the 2 measurement points of the width Lpmax.

[0014] The anchoring means, therefore the hollow, can be circumferentially continuous, going all the way around the tire, or circumferentially discontinuous, that is to say formed of circumferential portions which are separate from each other.

[0015] The recess allows the sidewall insert to be engaged in the thickness of the sidewall, so as not to create a significant protuberance relative to the axially outer face of the sidewall, and therefore not to disturb the flow of air in the vicinity of the sidewall in this area. To do this, the recess has, in a meridian plane (YZ) containing the axis of rotation (YY') of the tire, a depth Pc, maximum distance measured perpendicularly between the axially outer face of the sidewall and the bottom of the recess, preferably at least equal to 2 mm, preferably in each meridian plane (YZ) where the recess is present in the case of a discontinuous recess. For optimal operation of the sidewall, the recess which determines the width of the insert, has a width Le, measured, at the level of the axially external face of the sidewall, between the two hollow walls, in a plane containing the radial axis, at most equal to 15% of the nominal section height H of the tire.

[0016] The axially outer sidewall layer in which the anchoring means is formed extends axially from an axially outer sidewall face, in contact with atmospheric air, to an axially outermost reinforcing layer, formed of reinforcements, most often textile. More precisely, the axially outer sidewall layer is in axially internal contact with the rubber mixture coating the reinforcements of the axially outermost reinforcing layer, usually called the coating mixture.

[0017] The hollow anchors the insert in the sidewall by blocking the edges of the sidewall insert between its walls. It therefore helps to hold the sidewall insert in place, which may be ejected during rolling.

[0018] According to the invention, to improve the mechanical strength of the insert on the protuberance, each sidewall insert cooperates with the anchoring means by adhesion, by means of an adhesive, on a total bonded surface consisting 100% of a surface bonded to the protuberance. To allow good adhesion but also the possibility of changing the insert without damaging the sidewalls of the tire, in particular the edges of the hollow, it is advisable to locate the adhesive on the protuberance.

[0019] Still according to the invention, to preserve the integrity of the sides in the event of an insert change but also excellent mechanical strength of the glue and therefore of the insert, at least 80% of the total glued surface is located on the total surface Stpl of the second wide portion of the protuberance. Indeed, due to the particular shape of the protuberance, the deformations of the protuberance are very low so that they generate very little stress in the glue located at the interface of the insert. Indeed, the end of the protuberance is the part of the anchoring means whose mechanical behavior is closest to the insert. It constitutes the most effective and most resistant gluing zone over time. Furthermore, for aesthetic reasons, it is desirable that no excess glue appears. The glue placed on the second wide portion of the protuberance will be difficult to escape from the space between the partfemale part of the insert and the male part of the protrusion. Avoid placing glue on the walls of the hollow to prevent any glue from rising out of the hollow but also because of the shearing that the glue present in this area would undergo due to the deradialization of the sidewall which would harm its mechanical strength. The more the glue is placed on the second wide portion of the protrusion, the more effective the bonding is in its mechanical strength and without aesthetic impact. This is also the best place to place the glue in order to be able to remove the insert without damaging the tire, in particular the protrusion. Indeed, if minimal portions of the tire are removed with the insert when it is removed to be changed, this will not affect the strength of this area, the furthest from the reinforcements of the carcass layers and nevertheless the thickest, and moreover completely hidden by the new replacement insert.Furthermore, to replace the insert, by cutting the insert and pulling axially one of the cut ends, the glue will be made to work in extension, which is the best method of detachment, which is not possible with the other portions of the protrusion or the anchoring means. Having glue on the first narrow portion has the disadvantage of taking the risk of breaking this area in the event of detachment to change the insert and therefore of tearing off the protrusion, which would hinder the replacement of the insert or even make it impossible or weaken the mechanical strength of the replacement insert. Having glue on the walls of the hollow has the disadvantage of coupling the tire sidewalls to the insert and therefore transmitting shear deformations to it with the risk of cracking the insert.Furthermore, if the insert is replaced, if pieces of the walls come with the insert, the aesthetic appearance of the tire will be degraded, which is not acceptable.

[0020] Preferably, 100% of the total bonded surface is located on the total surface Stpl of the second wide portion of the protuberance.

[0021] According to one embodiment of the invention, the surface glued to the second wide portion of the protuberance constitutes between 3% and 80% of the total surface Stpl of the second wide portion of the protuberance, preferably between 10% and 40% of the total surface Stpl of the second wide portion of the protuberance. Depending on the mechanical strength of the glue, almost the entire total surface Stpl of the second wide portion of the protuberance will be coated except for the edges connecting to the first narrow portion of the protuberance, i.e. 80% of the surface Stpl or regular dots of surface glue will be placed negligible compared to the total surface area Stpl of the second wide portion of the protuberance. It will also be possible to proceed piece by piece with enlarged glue points or wide areas interspersed with areas without glue in order to ensure at the same time a very good bonding and areas without glue allowing with a cut of the insert to have a first traction zone to detach the insert by traction on the glue.

[0022] For these reasons, according to one of the embodiments of the invention, the glue is present discontinuously between the insert and the tire according to bonding zones distributed in a substantially regular circumferential manner, the bonding zones having a width of between 50 and 100% of the width Lpmax of the second wide portion of the protuberance and a circumferential length of between 0.5 times and 20 times the width of the bonding zone, preferably between 1 time and 3 times the width of the bonding zone.

[0023] To optimize the gluing of the insert, control the quantity of glue and the quality of the gluing, the total surface Stpl of the second wide portion of the protrusion includes recesses with a depth of between 0.1 and 2 mm, preferably between 0.1 and 0.5 mm and suitable for receiving glue. The operator who has to position the insert, therefore knows where and what maximum quantity of glue he must put to ensure mechanically and ecologically optimal gluing. By ecologically optimal we mean to use the right quantity of glue.

[0024] To ensure this optimum, the recesses on the surface of the second wide portion of the protuberance have a width of between 50 and 95% of the width Lpmax of the second wide portion of the protuberance and a circumferential length of between 0.5 times and 20 times the width of said recesses, preferably between 1 time and 3 times the width of said recesses.

[0025] To allow easy replacement of the insert, it is advantageous that the total surface Stpl of the second wide portion of the protuberance includes several series of recesses with a depth of between 0.1 and 2 mm and suitable for receiving glue, each series of recesses being optically differentiable from the other series. After the removal of a first insert, the recesses used are no longer easily usable either because glue or insert films still remain there, or because the damaged edges recesses are no longer able to hold the glue within their limits. It is useful to have at least a second set of recesses, and more if possible, distributed regularly over the second wide portion of the protrusion, in order to be able to proceed with the installation of another insert while maintaining the optimal quality of the bonding both in mechanical efficiency and in quantity of glue. To facilitate the use of these series of recesses, each series will be recognizable by optical means either its shape or a texture in the background of the recess with or without a difference in contrast of black, a color or other suitable optical means.

[0026] Tests have shown that the bonded surface area of ​​the second wide portion of the protrusion depends on the size of the tires and in particular on the height of their sidewalls. Thus, for a tire whose radial height H is less than 90 mm, the circumferential length of the bonded surface is preferably between 20 and 100% of the circumferential length of the anchoring means, preferably between 50 and 100% of the circumferential length of the anchoring means and more preferably between 70 and 100%. For a tire whose radial height H is between 90 mm and 110 mm, the bonding zones are preferably distributed circumferentially and located at circumferential distances of between 2 and 30 cm, preferably between 2 and 15 cm.Finally, for a tire whose radial height H is greater than 110 mm, the bonding zones are preferably distributed circumferentially and located at circumferential distances between 2 and 40 cm, preferably between 5 and 20 cm.

[0027] Indeed, during use, the sidewall deforms, particularly when it passes through the contact patch with the ground. This circumferential deformation increases from the bead wire, due to the relative rigidities of the bead wire, the sidewall and the crown, to the contact patch. Having different radii and the insert not being part of the tire, the walls of the hollows and the walls of the insert deform differently, creating movements, particularly in compression, which dislodge the insert from the anchoring means. Increasing the size of the sidewall greatly reduces this phenomenon. The height H of a tire is defined by the usual standards relating to tires, such as, for example, the standard of the "European Tire and Rim Technical Organization" or "ETRTO" standard.

[0028] The preferably colored sidewall insert may have one or more colors differentiated from the usually black color of the sidewall. Preferably again, the sidewall insert is monochrome in order to simplify its manufacture. The sidewall insert may be continuous circumferentially or in pieces.

[0029] According to particular embodiments, to further differentiate it from the sidewall, the sidewall insert is covered with a graphic or texture, for example microtexture or velvet, suitable for creating contrast effects, or tinted throughout.

[0030] Preferably, the tire is asymmetrical and preferably non-directional and comprises an anchoring means intended to cooperate with at least one sidewall insert on only one of the two sidewalls of the tire. It is not relevant to have an insert in the sidewall positioned on the inside of the vehicle, for a four-wheeled vehicle, because it is not visible. It is therefore advantageous to have an anchoring means only on one sidewall of the tire. The tire is therefore already asymmetrical by its sidewalls, it is therefore advantageous that this asymmetry is reflected on the sculpture, one side of the tread being to be placed 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 that the tire is not directional.So to respect the axisymmetry of the tire, it is enough to turn the right tire in relation to the left tire on the same axle, so that the right tire is symmetrical in relation to the plane perpendicular to the axle of the left tire.

[0031] In the case of a hollow and an insert being discontinuous and being made up of several parts each having 2 circumferential ends, the insert as a whole therefore having a series of circumferential ends, it is advantageous for good mechanical strength and in particular of said ends of the insert over all of its parts that the distance at each circumferential end of the insert to the nearest bonding zone is at most equal to 2 cm and preferably at most equal to 1 cm.

[0032] The characteristics of the invention are illustrated by schematic figures 1 to 3, not shown to scale.

[0033] Figure 1 is a half-meridian section of a tire 1 according to the invention mounted on a rim 2 and equipped with a sidewall insert 9 clipped into the sidewall 3. The sidewall 3, connecting the top 4 respectively to the bead 5, comprises, on its axially external flank face 31, a protective cord 32. The flank 3 also comprises an anchoring means 6, comprising at least one hollow 7 and a protuberance 8 in relief, and intended to cooperate with the flank insert 9.

[0034] Figure 2 is a detail of the half-section of Figure 1 showing the anchoring means 6, comprising at least one hollow 7, of a depth Pc, delimited axially inwards by a hollow bottom 71 and radially by two hollow walls 72, and a protuberance 8, in relief relative to the hollow bottom 71 and extending from the hollow bottom 71 to the vicinity of the axially outer face of the flank 31. The protuberance 8 is constituted by a step of a first narrow portion 81 extending axially outwards from the hollow bottom 71 and having a minimum width equal to the minimum protuberance width Lpmin, and a second wide portion 82 extending axially outwards from the first narrow portion 81 and having a maximum width equal to the maximum protuberance width Lpmax, and a total external surface Stpl. Figure 2 shows a recess 821 on the total external surface Stpl of the protrusion 8.The widths Le, Lpmin, Lpmax are substantially radial corrected for the angle of the surface of the flank 31 with the radial axis. Their measurements are made orthogonally to the circumferential axis along the direction of the surface of the flank, that is to say in a plane containing the radial direction.

[0035] Figure 3 shows an example of two series of recesses 821 on the total external surface Stpl of the protuberance 8 of the anchoring means 6, capable of receiving glue, each series of recesses 821 being optically differentiable by 2 different shapes, oval and rectangular, and by two different bottom surfaces, striated and tiled.

[0036] The inventors have more particularly studied this invention for a tire of dimension 275 / 35 R 21 103 Y XL, intended to be inflated to a recommended pressure equal to 2.9 bars and to carry a maximum load equal to 875 kg.

[0037] The tire according to the invention was compared to a control tire according to the state of the art. The anchoring means of the two tires have the same geometry as well as the inserts which are clipped onto protuberances. Only the use of glue changes for the tire according to the invention.

[0038] Tests on a sporting use on a circuit with strong bends for maximum lateral thrusts greater than 1 g over a distance of 50 km generated local dislocations outside the anchoring means on the control tire. The same test for the tire according to the invention showed that the insert remained clipped onto the tire according to the invention over its entire length.

[0039] Tests were carried out on 245 / 45 RI 8 tires with a sidewall height H of 110 mm. Tests were carried out on various uses with high transverse accelerations or under pressure conditions (-1.2 bar compared to the nominal pressure) on a test vehicle on a private circuit. The invention was tested with glue points all placed on the wide portion of the protuberance, with a distance of 3 cm between them and 7 cm. In both cases, the tire and the insert according to the invention, unlike the control tire, did not separate.

[0040] Insert change tests with gluing on a tire where 80% of the total glued surface is located on the total Stpl surface of the second wide portion of the protrusion, have shown that with this solution the insert change is possible without any impact on the tire. The first gluing tests with a significant deposit of glue in the hollow and on the walls of the hollow, showed a lower mechanical resistance at the interface between the insert and the anchoring means after rolling than for the areas of the protrusion and the insert change without damaging the aesthetics of the tire proved impossible.

[0041] These tests demonstrate the interest of the invention.

Claims

Claims 1. Tire (1) for a light vehicle, intended to be mounted on a rim (2) and equipped with at least one sidewall insert (9), said tire (1) having a nominal section of radial height H and comprising: -two sides (3) connecting a top (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 at least one sidewall insert (9), -the anchoring means (6) extending continuously or discontinuously in a circumferential direction (XX') of the tire, and comprising a hollow (7) formed in the sidewall (30), extending from an axially outer face of the sidewall (31) axially towards the inside of the sidewall (3), - the hollow (7) being delimited axially towards the inside by a hollow bottom (71) and radially by two hollow walls (72), - the anchoring means (6) comprising a protuberance (8), in relief relative to the hollow bottom (71) and extending from the hollow bottom (71) to the vicinity of the axially external face of the flank (31) - the protuberance (8) being constituted, in a meridian plane (YZ), by a staggering of a first narrow portion (81) extending axially outwards from the hollow bottom (71) and having a minimum width equal to the minimum protuberance width Lpmin, and of a second wide portion (82) extending axially outwards from the first narrow portion (81) and having a maximum width equal to a maximum protuberance width Lpmax, at least equal to 1.1 *Lpmin. and a total external surface Stpl, - each sidewall insert (9) cooperating with the anchoring means (6) by engagement in the hollow (7) of the anchoring means (6) and by clipping onto the protuberance (8) of the anchoring means (6) characterized in that each sidewall insert (9) cooperates with the tire (1) by adhesion, by means of an adhesive, on a total bonded surface consisting 100% of a surface bonded to the protuberance (8), and in that at least 80% of the total bonded surface is located on the total surface Stpl of the second wide portion (82) of the protrusion (8).

2. Tire (1) according to claim 1 wherein 100% of the total bonded surface is located on the total surface Stpl of the second wide portion (82) of the protuberance (8).

3. Tire (1) according to one of claims 1 or 2 wherein the surface bonded to the second wide portion (82) of the protuberance (8) constitutes between 3% and 80% of the total surface area Stpl of the second wide portion (82) of the protuberance (8), preferably between 10% and 40% of the total surface area Stpl of the second wide portion (82) of the protuberance (8).

4. Tire (1) according to any one of the preceding claims in which the glue is present discontinuously between the insert and the tire according to bonding zones distributed in a substantially regular manner circumferentially, the bonding zones having a width of between 50 and 100% of the width Lpmax of the second wide portion (82) of the protuberance (8) and a circumferential length of between 0.5 times and 20 times the width of the bonding zone, preferably between 1 time and 3 times the width of the bonding zone.

5. Tire (1) according to any one of the preceding claims in which the total surface Stpl of the second wide portion (82) of the protuberance (8) comprises recesses (821) with a depth of between 0.1 and 2 mm, preferably between 0.1 and 0.5 mm, and capable of receiving glue.

6. Tire (1) according to claim 5 wherein the recesses (821) of the surface of the second wide portion (82) of the protuberance (8) have a width of between 50% and 95% of the width Lpmax of the second wide portion (82) of the protuberance (8) and a circumferential length of between 0.5 times and 20 times the width of said recesses (821), preferably between 1 time and 3 times the width of said recesses (821).

7. Tire (1) according to one of claims 5 or 6 in which the total surface area Stpl of the second wide portion (82) of the protuberance (8) comprises several series of recesses (821) with a depth of between 0.1 and 2 mm and capable of receiving glue, each series of recesses (821) being optically distinguishable from the other series.

8. Tyre (1) according to any one of the preceding claims, the radial height H of which is less than 90 mm, in which the circumferential length of the bonded surface is between 20 and 100% of the circumferential length of the anchoring means, preferably between 50 and 100% of the circumferential length of the anchoring means and more preferably between 70 and 100% of the circumferential length of the anchoring means.

9. Tire (1) according to claim 4, the radial height H of which is between 90 mm and 110 mm, in which the bonding zones are distributed circumferentially and located at circumferential distances of between 2 and 30 cm and preferably 2 and 15 cm.

10. Tire (1) according to claim 4, the radial height H of which is greater than 110 mm, in which the bonding zones are distributed circumferentially and located at circumferential distances of between 2 and 40 cm and preferably 5 and 20 cm.

11. Tire (1) according to claim 4, the insert being discontinuous and having a series of circumferential ends, wherein the distance at each circumferential end of the insert to the nearest bonding zone is at most equal to 2 cm and preferably at most equal to 1 cm.

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