Method for placing a sidewall insert on a tyre

Abstract

The invention relates to a method for attaching a sidewall insert to a tyre (1) that is provided with an anchoring means (6) and comprises a recess formed in the sidewall (3) thereof, the insert being capable of being inserted and clipped into the recess. The tyre is mounted on its rim and inflated to a pressure of at least 1 bar, an adhesive is applied to a portion of the anchoring means, the insert is inserted into the recess at a first insertion point by clipping it onto the projection, and then, from the first insertion point, by a pressure exerted circumferentially, the entire insert is clipped onto the projection.

Description

Process for installing a sidewall insert on a tire

[0001] The present invention relates to the method of fixing a decorative insert intended to personalize the design of the tire sidewall, for 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.

[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" and "radially outward" respectively mean "closer" and "further" respectively from the axis of rotation of the tire. By "axially inward" and "axially outward" respectively, is meant "closer" and "further" respectively from the equatorial plane of the tire, the equatorial plane of the tire being the plane passing through the middle of the tread 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. providing the mechanical connection between the tire and the rim on which it is intended to be mounted, the most radially inner contact zone of the tire to the rim being made by the bead of the tire.

[0006] 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.

[0007] 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 bead. However, this trim element is likely to deform and detach from the sidewall, particularly when hitting curbs or when cornering with strong transverse thrust. It is therefore important to glue the insert without contaminating the tire, particularly its outer surface, with glue and in such a way as not to risk damaging the insert when clipping it in or when mounting the tire on its rim, with good quality installation of the insert.

[0008] The inventors set themselves the objective of proposing a method for fixing an insert to a tire capable of being equipped with at least one sidewall insert, meeting all of these criteria.

[0009] This objective was achieved by a method of fixing a sidewall insert to a tire provided with an anchoring means comprising a hollow formed in a sidewall, - the anchoring means extending continuously or discontinuously in a circumferential direction of the tire, - the insert being able to be inserted into the hollow and clipped by means of anchoring, - the method comprising: - a first preparation phase, during which the tire is mounted on a rim - a second gluing phase, during which part of the insert or anchoring means is glued with glue, - a third insertion phase, during which the insert is engaged in the hollow at a first insertion point by clipping it using anchoring means, then from the first point insertion, by pressure exerted progressively circumferentially, the entire insert is clipped onto the protuberance.

[0010] The anchoring means, for a flank insert, comprises 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 innermost circumferential wall. Therefore the anchoring means comprises at least one radially outermost circumferential wall and one radially innermost circumferential wall, both of which may or may not belong to the same hollow.

[0011] The insert is capable of being inserted into the hollow and clipped by anchoring means, namely that the anchoring means comprises mechanical means capable of retaining the insert in position in the hollow.

[0012] 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.

[0013] The hollow 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 hollow 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 hollow, at least equal to 2 mm, preferably in each meridian plane (YZ) where the hollow is present in the case of a discontinuous hollow. For correct operation of the sidewall, the hollow which determines the width of the insert, has a width Le, measured, at the axially outer 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.

[0014] The axially outer layer of flank in which the anchoring means is formed extends axially from an axially outer face of the flank, in contact with atmospheric air, to an axially most reinforcing layer outer, 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 reinforcement layer, usually called the coating mixture.

[0015] The anchoring means allows the insert to be clipped into the sidewall. By clipping, we mean that clipping the insert into the anchoring means requires the application of a force thereon capable of elastically deforming the anchoring means and / or the insert to allow movement of the insert in the anchoring means and that once clipping has been carried out, the separation of the insert from the anchoring means requires the application of a force at least twice greater than the force of gravity of the insert. It therefore contributes to maintaining the sidewall insert in the anchoring means during handling of the tire and during rolling. To improve the mechanical strength of the insert, an adhesive is used to secure the insert and the anchoring means, the adhesive being placed on the anchoring means or on the insert, "or" being inclusive in this case.A solution included in the invention is that the glue is already placed on the insert and protected by a film removed when carrying out the process during the bonding phase. It is essential to be able to correctly center the insert on the tire that the sidewalls of the latter have a fixed shape and a certain rigidity to pressure. Similarly, mounting on a rim, a tire in which the insert is already in place, using the usual steel tools, would risk damaging the insert or requiring the use of a more resistant material for the insert than necessary for a very short phase of its use. The first phase of the process therefore consists of mounting the tire on its rim, that is to say applying at least a pressure capable of positioning the beads of the beads on the rim. Such a pressure varies according to the type of tire and the geometry of the rim. A pressure of around 1 bar is generally sufficient.It is important to maintain this internal pressure to ensure sufficient rigidity of the tire sidewalls to facilitate clipping of the insert into the anchoring means. This phase can be completed if necessary by cleaning the anchoring means and the insert if necessary. In fact, when mounting the tire on its rim, it is customary to use grease, which must be removed if it has ever soiled the anchoring means or the insert. Similarly, dust and airborne pollution must be avoided as much as possible at the interface between the. anchoring means and the insert. Thus it is preferable that the tire and / or insert are cleaned during the preparation phase after mounting the tire on a rim, preferably by blowing with compressed air with or without spraying a degreaser. The inside of the insert can be protected by a film to be removed during this cleaning phase. The film simply protects the surface of the insert from dust or a glue placed beforehand, or a product improving adhesion with the glue or optimizing the setting time such as an activator. An activator can thus be applied before gluing on one of the surfaces to be glued, the glue is then deposited on the other opposite surface. The activator makes it possible to accelerate the polymerization, therefore to reduce the setting time.

[0016] Once the tire and insert are ready, the anchoring means is glued with glue. To prevent the glue from spreading over the entire sidewall by gravity, which would be unsightly and contrary to the objective of installing a sidewall insert, the tire will be placed on a means capable of positioning the tire such that its rotation axis is substantially vertical, preferably on a standard tire mounting machine with a substantially vertical rotation axis, preferably on a standard tire mounting machine with a motorized substantially vertical rotation axis. This means can be a simple table but also a mounting machine that allows the insert to be placed immediately after mounting the tire on its rim. This equipment is all the more interesting because it prevents any movement of the tire and the rim and improves the ergonomics of insert installation.By substantially vertical, we mean any inclination of the axis allowing a better view of the tire during the operation. For greater ergonomics, the glue and the insert can be placed on a trolley near the means used to install the tire during the insertion process.

[0017] To avoid having to remove the tire from the rim used to fit the insert, then refit it on another rim, in this case that of a vehicle, in order not to damage the insert during the removal and then fitting operations, the insert should preferably be fitted once the tire has been fitted to the wheel intended to equip the vehicle.

[0018] It is always possible to glue the inside of the insert before gluing it to the tire, but the risk of spreading glue on the tire during this operation or when centering the insert before clipping it is very high and this does not correspond to the objectives of the invention. Conversely, placing the insert on the table and then placing the tire on it is not ergonomic.

[0019] The third phase of the process consists of engaging the insert in the hollow of the anchoring means at a first insertion point by clipping it onto the protuberance, then from the first insertion point, by pressure exerted circumferentially, the entire insert is clipped onto the protuberance. This allows for optimal centering.

[0020] In a preferred embodiment, in the insertion phase, a tool is used which is capable of exerting pressure on the insert circumferentially from the first clipping point, and of clipping the entire insert onto the protuberance, preferably a wheel. The wheel makes it possible to avoid shearing forces on the insert and to mainly generate forces for inserting the insert into the anchoring means. This makes it possible not to damage the insert during assembly. Preferably, the insertion phase comprises, after clipping, a circumferential pressing sub-phase capable of driving oxygen away from the interface between the insert and the anchoring means to improve the polymerization of the adhesive.

[0021] An advantageous solution is for the glue to have a setting time of no more than 2 minutes, preferably no more than 30 seconds and no less than 15 seconds. To proceed efficiently, the glue must set between the insert and the tire in a time compatible with a commercial operation on a tire. If the glue sets too quickly, i.e. before 15 seconds, the glue may set before the operator has finished mounting and therefore the adhesion of the insert to the anchoring means will not be optimal - particularly on the parts where the glue will have set without being at the interface of the insert and the anchoring means. A setting time of no more than 10 minutes, preferably no more than 3 minutes, must give the operator time to correctly carry out the installation with a glue capable of setting without having to wait too long before being able to mount the tire rim assembly on the vehicle or give the product to the customer.Complete drying is often achieved after 24 hours. Setting time is the time after which the bonding performance is sufficient for handling. The insert assembly is clipped into the tire in the garage without the bond breaking significantly. Under normal conditions, for certain adhesive formulations, atmospheric humidity initiates the polymerization process of the adhesive. Although the setting time is relatively short, it is often necessary to wait several hours before the chemical resistance of an adhesive is fully achieved. The setting time depends on the different materials, temperature and humidity. The setting time is defined as the time required to develop a shear strength of 0.1 N / mm2 at 23° and 50% humidity.

[0022] It is advantageous for a drying phase to follow the insertion phase, lasting at most two days and at least 2 minutes before mounting the tire on the vehicle, preferably at least 2 hours before mounting the tire on the vehicle, to allow optimal adhesion of the insert to the tire before use of the tire.

[0023] In a preferred solution, 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 measurement points of the width Lpmax.

[0024] Preferably, the gluing is carried out on all or part of the external surface Stpl of the second wide portion of the protuberance, in order to optimize the gluing. For better mechanical strength, it is important that the second wide portion of the protuberance includes glue. 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 have difficulty escaping from the space between the female part of the insert and the male part of the protuberance during clipping.We will avoid placing glue on the walls of the hollow in order 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 protuberance, up to 100%, 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 protuberance. Indeed, if minimal portions of the tire are removed with the insert, this will in no way impact the strength of this area, the furthest from the reinforcements of the carcass layers and nevertheless thick, 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 prevent any replacement of the insert. Having glue on the walls of the hollow has the disadvantage of coupling the sidewalls of the tire to the insert and therefore of transmitting the shear deformations to it with the risk of cracking the insert. Furthermore, in the event of replacement of the insert, if pieces of the walls come with the insert, the aesthetic appearance of the tire will be degraded, which is not acceptable.

[0025] Depending on the mechanical strength of the glue, almost the entire Stpl surface area 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 Stpl surface area, or glue dots of negligible surface area will be regularly placed compared to the total Stpl surface area of ​​the second wide portion of the protuberance. It will also be possible to proceed piece by piece with enlarged glue dots or wide areas interspersed with glue-free areas in order to ensure at the same time very good bonding and glue-free areas allowing, with a cut of the insert, to have a first traction area to detach the insert by traction on the glue.

[0026] For these reasons, according to one of the embodiments of the invention, the glue is present discontinuously between the insert and the tire in 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 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.

[0027] 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 protuberance includes recesses with a depth of between 0.1 and 2 mm, preferably between 0.1 and 0.5 mm, suitable for receiving glue. The operator who has to place the insert thus 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. In this case, the gluing phase consists of placing the glue only in said recesses.

[0028] 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.

[0029] The preferably colored sidewall insert may have one or more colors differentiated from the usually black color of the sidewall. Even more preferably, the sidewall insert is monochrome in order to simplify its manufacture. The sidewall insert may be continuous circumferentially or in pieces.

[0030] 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.

[0031] 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.

[0032] The invention also applies to piecewise circumferential inserts. The insertion phase will need to be repeated for each piece of the insert.

[0033] The characteristics of the invention are illustrated by schematic figures 1 to 2, not shown to scale.

[0034] Figure 1 is a half-meridian section of a tire 1 usable in the method 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 crown 4 respectively to the bead 5, comprises, on its axially outer sidewall face 31, a protective cord 32. The sidewall 3 also comprises an anchoring means 6, comprising at least one hollow 7 and a raised protuberance 8, and intended to cooperate with the flank insert 9.

[0035] 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.

[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, provided with a hollow on its sidewall comprising an anchoring means with a hollow and a protuberance, was fitted with an insert using the method according to the invention. The tire was mounted on a standard wheel according to ETRTO, "European Tire and Rim Technical Organization" on a commercially available motorized mounting machine with a vertical rotation axis. The operator degreased the parts to be bonded. The operator then glues the recesses suitable for receiving the glue, present on the protuberance. He then positions the insert on the hollow. With a roller - a tool equipped with a handle and ending in a wheel with a diameter between 3 and 10 cm - he pushes the insert into the hollow, until it clips at this point, then while maintaining pressure, he starts the rotation of the mounting table while keeping the roller under pressure and following the insert so as to roll the wheel without generating shear in the insert. The gluing time is about ten seconds, the clipping time about 15 seconds. The tires are left to dry for around 2 hours. The tires thus equipped with inserts have undergone rolling tests without showing any failure of the insert-tire connection.

[0038] These tests demonstrate the interest of the invention.

Claims

Claims 1. Method for fixing a sidewall insert (9) on a tire (1) provided with an anchoring means (6) comprising a hollow (7) formed in a sidewall (3) and a raised protuberance (8), - the anchoring means (6) extending continuously or discontinuously in a circumferential direction (XX') of the tire, - the insert (9) being capable of being inserted into the hollow (7) and clipped by means of anchoring (6), characterized in that the method comprises: - a first preparation phase, during which the tire (1) is mounted on a rim (2), - a second gluing phase, during which part of the insert (9) or the anchoring means (8) is glued with glue, - a third insertion phase, during which the insert (9) is engaged in the hollow (7) at a first insertion point by clipping it using the anchoring means (6), then from the first insertion point, by pressure exerted progressively circumferentially, the entire insert is clipped onto the protuberance.

2. Method for fixing a sidewall insert on a tire (1) according to claim 1, in which the tire (1) and / or the insert (9) are cleaned during the preparation phase after mounting the tire (1) on a rim (2).

3. Method for fixing a sidewall insert (9) on a tire (1) according to any one of the preceding claims, in which the method is implemented on a means capable of arranging the tire such that its axis of rotation (YY') is substantially in a vertical position, preferably on a standard tire mounting machine with a vertical axis of rotation, preferably a standard tire mounting machine with a motorized vertical axis of rotation.

4. Method for fixing a sidewall insert (9) on a tire (1) according to any one of the preceding claims, in which, in the insertion phase, a tool is used capable of exerting pressure on the insert (9) of circumferentially from the first clipping point, and clip the entire insert onto the protrusion, preferably a wheel.

5. Method for fixing a sidewall insert (9) on a tire (1) according to any one of the preceding claims, in which the insertion phase comprises, after clipping, a circumferential pressing sub-phase.

6. Method for fixing a sidewall insert (9) on a tire (1) according to any one of the preceding claims, in which the glue has a setting time at most equal to 10 minutes, preferably at most equal to 3 minutes and at least equal to 15 seconds.

7. Method for fixing a sidewall insert (9) on a tire (1) according to any one of the preceding claims, comprising a drying phase, following the insertion phase, of a duration at most equal to two days and at least equal to 2 minutes before mounting the tire on the vehicle, preferably at least equal to 2 hours before mounting the tire on the vehicle.

8. Method for fixing a sidewall insert (9) on a tire (1), the tire having an anchoring means (6) comprising a protuberance (8), in relief relative to a hollow bottom (71), extending from the hollow bottom (71) to the vicinity of the axially outer face of the sidewall (31), the protuberance (8) being constituted, in a meridian plane (YZ), by a step of a first narrow portion (81) extending axially outward 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 outward 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, the insert (9) being capable of being clipped onto the protuberance (8) of the anchoring means (6), according to any one of the preceding claims, in which, during the bonding phase, the bonding is carried out on all or part of the external surface Stpl of the second wide portion of the protuberance.

9. Method for fixing a sidewall insert on a tire (1) according to claim 8, the tire having an anchoring means (6) having a protuberance (8) comprising a second wide portion (82) comprising recesses (821) circumferentially distributed on its external surface Stpl and capable of receiving glue, in which the gluing phase consists of placing the glue only in said recesses (821).

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