Patent ID: 12240193

In order to make them easier to understand, the figures are not shown to scale.

DETAILED DESCRIPTION OF THE INVENTION

In what follows, the terms “rubber gum”, “rubber compound”, “rubber” and “compound” are used interchangeably to identify rubber constituents of the tyre.

The circumferential direction of the tyre, or longitudinal direction, is the direction corresponding to the periphery of the tyre and defined by the direction of running of the tyre.

The transversal or axial direction of the tyre is parallel to the axis of rotation of the tyre.

The radial direction is a direction which crosses the axis of rotation of the tyre and is perpendicular thereto.

The axis of rotation of the tyre is the axis about which it turns in normal use.

A radial or meridian plane is a plane which contains the axis of rotation of the tyre.

The circumferential median plane, or equatorial plane, is a plane perpendicular to the axis of rotation of the tyre and which divides the tyre into two halves.

FIG.1shows a half-view of a tyre which extends symmetrically relative to the circumferential median plane, or equatorial plane, of a tyre.

InFIG.1, the tyre1is of size 12 R 22.5. The tyre1comprises a radial carcass reinforcement2anchored in two beads3. The carcass reinforcement2is hooped at the crown of the tyre by a crown reinforcement5, itself capped by a tread6.

The carcass reinforcement2, formed by a single layer of metal cords, is wound, in each of the beads3, around a bead wire4and forms, in each of the beads3, a turn-up of the carcass reinforcement layer7having an end8.

The carcass reinforcement2is formed of reinforcing elements between two skim layers.

FIG.1illustrates the tyre fitted on its nominal rim J; the axially outermost point E of the main part of the carcass reinforcement layer2is thus determined with the tyre inflated to its nominal pressure, for example by tomography.

FIG.2illustrates, in an enlargement, a schematic cross-sectional depiction of a bead3of the tyre ofFIG.1in which a part of the carcass reinforcement layer2is wound around a bead wire4in order to form a turn-up7having an end8.

The turn-up7of the carcass reinforcement layer2is separated from the main part of the carcass reinforcement layer2by a first layer of rubber compound9having a radially outer end10.

The first layer of rubber compound9is profiled in order to bear against the bead wire4and ensure the coupling and decoupling between the turn-up of the carcass reinforcement layer7and the main part of the carcass reinforcement layer2.

Shown axially on the outside of the turn-up7of the carcass reinforcement layer is a fourth layer of rubber compound11, the radially outer end12of which is radially on the inside of the end8of the turn-up7of the carcass reinforcement layer. According to another embodiment which has not been depicted, the radially outer end of the fourth layer of rubber compound is radially on the outside of the end8of the turn-up7of the carcass reinforcement layer.

The radially inner end13of the fourth layer of rubber compound11is radially comprised between the points A and B, which are the radially innermost and radially outermost points, respectively, of the circle circumscribed on the bead wire T.

In contact with the fourth layer of rubber compound11and radially under the bead wire, there is a second layer of rubber compound14, the axially outermost end15of which is radially on the inside of the end12of the fourth layer of rubber compound11.

Axially in contact with the first layer of rubber compound9, with the fourth layer of rubber compound11, and with the second layer of rubber compound14, there is a third layer of rubber compound16. The radially inner end17of the third layer of rubber compound16is radially on the inside of the end15of the second layer of rubber compound14.

The bead3also comprises a radio-frequency communication module20arranged axially on the outside relative to the interface between the carcass reinforcement turn-up7and the fourth layer of rubber compound11. This communication module20is positioned radially at the region of coupling between the main part2of the carcass reinforcement and the turn-up7of this carcass reinforcement, namely between the two points C and D inFIG.2. The communication module20is preferably arranged substantially in the middle of this coupling region, between C and D. The communication module20is embedded inside the fourth layer of rubber compound11at a distance greater than 2 mm and preferably greater than 3 mm from the interface.

This position affords the radio-frequency transponder of the communication module good mechanical protection and the Applicant has found experimentally that the distance greater than 2 mm from the metal threads of the turn-up7of the carcass reinforcement2provides good robustness of communication with an external reader even if the reading distances are practically identical or very similar compared with a communication module arranged at the interface between the turn-up7and the fourth layer of rubber compound. The reading distance is thus less subject to the random features of industrial scale manufacture than when the communication module is placed directly at the interface between the second communication layer and the skim layer of the layer of metal reinforcers of the turn-up7.

FIG.2also shows communication modules20a,20band20cplaced in alternative positions. The communication module20ais embedded inside the second layer of rubber compound radially on the outside relative to the point B; the communication modules20band20care both embedded in the third layer of rubber compound, the one that forms the surface of the sidewall of the tyre. These last two positions are highly beneficial from the viewpoint of communication between the communication module and an external reader, and of very good mechanical strength of the communication module that allows it to withstand the particularly harsh in-service mechanical stresses in the vicinity of the point E on the sidewall in particular.

FIG.6is an exploded view of a communication module20. This module20comprises a radio-frequency transponder30embedded between two layers22aand22bof a non-vulcanized electrically insulating rubber compound. The thickness of each layer is of the order of 1 to 2 mm, the length is of the order of 50 to 70 mm and its width is of the order of 10 to 20 mm. Such a communication module is a semi-finished product that can be incorporated into the structure of the tyre1during the manufacture of the latter.

The rubber compound22for encapsulating the radio-frequency transponder30contains 100 phr (parts by weight per 100 parts of rubber) of a polymer such as EPDM (ethylene propylene diene monomer rubber), butyl rubber, neoprene or a diene elastomer such as SBR (styrene-butadiene rubber), polybutadiene, natural rubber or polyisoprene.

The compound may contain fillers such as silica, carbon black, chalk and kaolin fillers:with a silica filler in a maximum amount of 50 phr;with a carbon black filler of ASTM grade higher than 700, in an amount lower than 50 phr;with a carbon black filler of grade lower than or equal to 500, in a maximum amount of 20 phr.It is possible to add or replace these fillers with chalk or kaolin.

Such amounts and types of fillers make it possible to guarantee a relative permittivity lower than 6.5, in particular at a frequency of 915 MHz.

The stiffness in the cured state of the encapsulating compound is preferably lower than or close to those of the adjacent rubber compounds.

FIG.7shows an alternative embodiment of the communication module20. In this embodiment, the radio-frequency transponder30is embedded in an electrically insulating rubber compound22and the assembly has a substantially cylindrical shape. The outside diameter of the radiating antenna31is of the order of 2 mm, and advantageously, the thickness of the layer of electrically insulating rubber between the exterior surface of the radiating antenna31and the exterior surface of the communication module is of the order of 1 mm. The semi-finished product or communication module20ready to be inserted into the slots in the profiled elements of suitable rubber compound therefore has a diameter of the order of 4 mm with a length of the order of 50 mm.

The radio-frequency transponder30of the communication module20such as shown inFIGS.6and7corresponds to the one described in document WO 2016/193457 A1, that will now be described.

The radio-frequency transponder30according to this embodiment of the communication module20comprises an electronic portion32and a radiating antenna31able to communicate with an external radio-frequency reader. It additionally comprises (seeFIG.8) a primary antenna34electrically connected to the electronic chip36and inductively coupled to the radiating antenna31. The radiating antenna is a dipole antenna consisting of a single-strand helical spring defining a first longitudinal axis39.

FIGS.6and7show a radio-frequency transponder30in a preferred configuration in which the electronic portion32is located inside the radiating antenna31. The geometric shape of the electronic portion32is circumscribed in a cylinder the diameter of which is smaller than or equal to the inside diameter of the helical spring. The introduction of the electronic portion32into the radiating antenna31is facilitated thereby. The median plane of the primary antenna is located in the central region of the radiating antenna and substantially superposed on the median plane of the radiating antenna.

It is also possible to arrange the electronic portion on the outside of the radiating antenna31.

FIG.8shows the electronic portion32of a radio-frequency transponder30intended for a configuration in which the electronic portion32is located in the interior of the radiating antenna31. The electronic portion32comprises an electronic chip36and a primary antenna34that is electrically connected to the electronic chip36via a printed circuit board40. The primary antenna here consists of a surface-mount-device (SMD) microcoil. The components on the printed circuit board are electrically connected using copper tracks37terminated by copper pads41. The components on the printed circuit board are electrically connected using the wire-bonding technique by gold wires42running between the component and the pads41. The assembly consisting of the printed circuit board40, of the electronic chip36and of the primary antenna34is embedded in a rigid mass43made of electrically insulating high-temperature epoxy resin forming the electronic portion32of the radio-frequency transponder30.

This radio-frequency transponder30has the advantage of being mechanically far stronger than conventional transponders.

Methods for installing a communication module20embedded inside the fourth layer of rubber compound are now described. The methods corresponding to the other three positions shown inFIG.2are entirely similar.

According to a first method for building a green form of tyre comprising a radio-frequency communication module20:a cylindrical green form comprising an annular bead wire interposed between an annular carcass reinforcement and a first layer of rubber compound is manufactured,a part of the carcass reinforcement is folded around the bead wire onto the first layer of rubber compound to form a turn-up of the carcass reinforcement; anda second profiled element consisting of at least a fourth layer of rubber compound which, comprises a communication module embedded within it, is applied to the turn-up.

Advantageously, before the second profiled element is laid on the turn-up of the carcass reinforcement, a slot is created starting from the surface of the fourth layer of rubber compound and the communication module or, as the case may be the radio-frequency transponder, is introduced into the slot.

As illustrated inFIG.9, it is possible when building the tyre to use a complex profiled element50and it is then very easy, before placing this complex, to create, for example by means of an ultrasound cutting device, a slot of dimensions and orientation suited to the rapid and repeatable placement of the radio-frequency transponder and, where appropriate, of its encapsulating rubbers.

This profiled element50comprises, on the free surface of the fourth rubber compound11, which surface is intended to come to bear against the turn-up of the carcass reinforcement, a slot52of dimensions suited to accommodating a communication module as depicted inFIGS.6and7. The slot52is also produced in such a way that the axis of symmetry39defined by the radiating antenna of the passive radio-frequency transponder of the communication module is oriented circumferentially. This slot52is produced using an ultrasound cutting device or vibrating blade defining an incision, for example in the shape of a U on the exterior surface of the complex profiled element50made up of two arms and a base. The orientation of the cutting device changes according to the altitude of the arms of the U so as to describe a radius about a fixed axis of the profiled element. Thus is created a V-shaped slot52or incision that may be seen in dotted line. This slot52opens by pivoting of the material about axis joining the two free ends of the U so that the communication module can be inserted into the slot52and so that the slot52can close again over the communication module when the latter is positioned in the slot. The profiled element50is then pressed down using a wheel in the region of the slot52in order to create anew a connection at the disjointed portions of the profiled element which are delimited by the slot52once the communication module has been introduced into the profiled element50.

As a preference, this slot52is oriented circumferentially when the profiled element50mounted on the green form of the tyre is shaped. The slot52has a long dimension in the future circumferential direction, which is parallel to the first longitudinal axis of the radiating antenna of the radio-frequency transponder. The depth of the slots52into the thickness of the profiled element50allows the radio-frequency transponder to be introduced to a depth of at least 2 millimetres from the exterior surface of the profiled element50that comprises the slot52. The slot52will be covered over by the carcass reinforcing layer turn-up in the case of the architecture of the tyre ofFIG.2. This will prevent any movement of the communication module within the profiled element50when the green form of the tyre is being manipulated up to the point at which the tyre in the cured state is finally completed.

According to another method for building the tyre:an inner rubber is placed on a cylindrical drum;the profiled elements of the second, third and fourth layers of rubber compound are applied in succession or as a complex;the two bead wires and the two profiled elements of the first layer of rubber compound are laid;the carcass is shaped to press it firmly against the interior surface of the two bead wires and profiled elements of the first layer;the second, third and fourth layers of rubber compound are folded around the bead wire and folded down onto the first layer of rubber compound; andthe manufacture of the green form of the tyre is completed then this green form is vulcanized to yield a tyre.

This method is such that before the second, third and fourth layers of rubber compound are folded around the bead wire, a slot is created starting from the surface of the profiled element of the fourth layer of rubber compound and the communication module is introduced into the slot.

In the aforementioned two methods for building a green form of a tyre, the slot at the surface of the fourth layer of rubber compound can be created before the profiled element is placed on the green form of the tyre or during this building of the green form of the tyre.

It is advantageous to use a semi-finished product that exhibits cylindrical symmetry for inserting the communication module into the slot, because of the greater ease of manipulation and placement: the only requisite being to correctly orientate to the axis of symmetry of the semi-finished product.

Such a semi-finished product with an axis of rotational symmetry is shown inFIG.7.

FIG.3shows a bead3of a tyre, chiefly for passenger vehicles. The carcass reinforcement2is anchored in the bead3by being turned up around the bead wire4. The carcass reinforcement reinforcing threads are textile threads; the first layer of compound9separates the main part of the carcass reinforcement2from the turn-up7. The turn-up7of the carcass reinforcement2extends up in the sidewall region beyond the radially exterior end of the first layer of compound9. The second layer of compound14, the layer that is in contact with the rim when the tyre is mounted thereon, and the third layer of compound16that forms the exterior surface of the tyre in the sidewall region, are in direct contact with the turn-up7. There is no fourth layer of rubber compound. This bead comprises a communication module20embedded in the second layer of rubber compound at a position that is radially exterior in relation to the bead wire4so as to be radially on the outside of the flange of the rim J once the tyre has been mounted, so as to ensure good communication between the communication module and an external reader. This figure also shows two alternative positions20aand20bin which the communication module is embedded in the third layer of rubber compound. As before, these two positions are rendered possible on account of the good mechanical strength of the communication module used.

FIG.4shows a bead3of a tyre, chiefly for vehicles of the van type. The carcass reinforcement2of the bead of this tyre is made up of two carcass plies2aand2b. The ply2ais anchored around the bead wire4by a turn-up7, and the ply2bis positioned externally relative to the ply2a. The two plies2aand2bare adjacent as far as the bead, where the ply2bcomes into contact axially on the outside with the turn-up7. The first layer of rubber compound9is thus applied between the main part of the ply2aand its turn-up7followed radially on the outside by the second ply2b. This bead comprises a fourth layer of rubber compound11applied axially between the second ply2band the second14and third16layers of rubber compound. This bead comprises a communication module20preferably embedded in the fourth layer of rubber compound11and very preferably radially at the level of the radially outer end10of the first layer of rubber compound9. This figure shows an alternative position for the communication module20a. This position is embedded in the third layer of rubber compound16in the vicinity of the point E (seeFIG.1).

FIG.5shows a tyre bead3usually used for heavy duty vehicles, in which the carcass reinforcement2comprises metal reinforcing threads and in which the end8of the turn-up7is positioned radially on the inside relative to the radially exterior end of the first layer of rubber compound9. This bead3comprises, as in the examples ofFIGS.2and4, a fourth layer of rubber compound11positioned axially between the first layer of rubber compound9and the second14and third16layers of rubber compound. ThisFIG.5shows the preferred position of the communication module20: embedded in the fourth layer of rubber compound11radially on the outside relative to the end8of turn-up7of the carcass reinforcement, or of any metal reinforcer that might be present in the bead3, so as to guarantee good electromagnetic communication.

Note the alternative position20afor the communication module, in which position said module is embedded in the first layer of rubber compound9. This position is very well protected mechanically, but also sufficiently distant from the carcass reinforcement (the communication module should preferably be at a distance greater than 2 mm and highly preferably of 3 mm away from the metal reinforcers) to guarantee industrially robust communication of the communication module with an external reader. The best position illustrated as20or20awill be selected according to the actual green tyre building method in order to disrupt this building as little as possible.

ThisFIG.5also shows a second alternative position for the communication module20b, embedded in the third layer16. As indicated previously, this position of the communication module is rendered possible because of the good resistance to stress loading of the communication module used.

In all the examples shown, it must be understood that each layer of rubber compound may comprise one or more layers of compound, of identical or different compound makeup, or may even contain metal or textile reinforcers if necessary.

Likewise, the examples given are nonlimiting and the method that forms the subject of the invention can be applied to any other type or field of application, such as notably to agricultural, construction plant, aircraft, tyres or to tyres for two-wheeled vehicles.

The method for inserting a communication module in a slot made in a profiled element before or whilst the constituent parts of the tyre are built into an assembly thus allows the communication module to be arranged in a large number of positions without disrupting the building of the green form of the tyre. This method is particularly advantageous when use is being made of a communication module that is cylindrical in shape with or without electrically insulating compound.