Heavy-duty pneumatic tires equipped with a high-frequency communication module

Description

Field of invention

[0001] The present invention relates to tires, and more particularly to a tire equipped with a radiofrequency communication module. State of the art

[0002] Already known in the state of the art, in particular from EP 1 977 912 B1, is a heavy goods vehicle tire equipped with a radio frequency communication module. In this document, the radio frequency communication module comprises a passive radio frequency identification transponder equipped with a helical radiating antenna forming a dipole. This type of transponder is generally designated by the English acronym RFID. Such a transponder can store data, for example relating to the identification, type and / or date of manufacture of the tire. WO 2016 / 060851 A, WO 2016 / 193457 A and WO2017 / 046245 A also describe tires equipped with radio frequency communication modules.

[0003] The tire described in WO 2018 / 011510 A comprises a single layer of radial carcass reinforcement anchored in each of the beads by turning up around a bead wire to form a main part and a turn-up, the turn-up being separated from the main part of the carcass reinforcement layer by a first layer of rubber compound and being axially outwardly in contact with a second layer of rubber compound, itself at least in contact with a third layer of rubber compound forming the outer surface of the tire in the bead area, the third layer of rubber compound being radially outwardly in contact with a fourth layer of rubber compound forming the outer surface of the sidewall of the tire. The tire described in EP 1 977 912 B1, as illustrated in figures 1 to 3, is intended to be mounted on a hollow rim (15° drop center). This tire comprises a radial carcass reinforcement, consisting of a single layer of carcass reinforcement formed of reinforcing elements inserted between two layers of rubber compound calendering, a crown reinforcement, itself radially capped with a tread, the tread being joined to two beads by means of two sidewalls. The layer of reinforcing elements of the carcass reinforcement is anchored in each of the beads by turning up around a bead wire to form a main part of the carcass reinforcement layer extending from one bead wire to the other and a turn up of the carcass reinforcement layer in each of the beads.The turn-up of the carcass reinforcement layer is separated from the main part of the carcass reinforcement layer by a first layer of rubber compound extending radially from the bead wire to beyond the end of the turn-up of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer extends axially outwards in contact with a second layer of rubber compound, itself at least in contact with a third layer of rubber compound forming the outer surface of the tire in the bead area, the third layer of rubber compound being intended in particular to come into contact with the rim. The third layer of rubber compound is radially outwards in contact with a fourth layer of rubber compound forming the outer surface of a sidewall. This tire is such that, in a meridian section: . the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire is of the order of 30% of the distance between the axially outermost point of the main part of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire, and the radiofrequency communication module is arranged in the bead at the interface between the first and second layers of rubber compound and radially between the end of the turn-up of the carcass ply and the radially outer end of the first layer of rubber compound.

[0004] This document specifies that this position allows optimal transmission of the data recorded in the radiofrequency communication module, in particular by preventing part of the communication module from extending into the volume of the bead located radially between the end of the turn-up and the rod. Brief description of the invention

[0005] The subject of the invention is a tire according to claim 1.

[0006] The applicant noted that this position of the radiofrequency communication module in the immediate vicinity of the metal reinforcement wires allows, despite this proximity, satisfactory radiofrequency communication with an external reader.

[0007] This position also has the advantage of being very favorable for the installation of the communication module during the manufacture of the tire. Indeed, the communication module is positioned on the turn-up of the carcass reinforcement layer which is mechanically stable ensuring a quality orientation of the communication module within the tire. And, the communication module is buried within the structure of the tire which protects it from potential aggressions coming from the outside such as impacts from sidewalks for example. In addition, the positioning at the interface between the second layer of rubber compound and the turn-up of the carcass reinforcement layer ensures that the communication module is sufficiently distant from the end of the turn-up of the carcass reinforcement layer which constitutes a singularity of rigidity within the architecture of the tire. This distance is beneficial to the endurance of the tire.Finally, this positioning of the communication module can allow coextrusion of all or part of the assembly consisting of the second, third and fourth layers of rubber mixture which provides a significant productivity gain in the production of a raw tire blank.

[0008] For the purposes of the invention, a hollow rim (15° drop center) or wedged seat rim is a one-piece rim, as defined in the ETRTO, the seats of which intended to receive the beads of the tire have a truncated cone shape, the angle formed with the axial direction being substantially equivalent to 15°. These seats are also extended by rim hooks of reduced height compared to rim hooks with flat bases whose rim seats have substantially cylindrical shapes.

[0009] The position of the axially outermost point E of the main part of the carcass reinforcement is determined on a tire mounted and inflated according to the nominal conditions. This determination can be carried out, for example, using a tomography technique.

[0010] The positions of the radially innermost points A and radially outermost points B of the circle circumscribed to the bead can also be determined using a tomography technique or are determined on a section of a tire, the bead spacing of which is the same as when the tire is mounted on the mounting rim recommended by ETRTO, the latter therefore being neither mounted nor inflated.

[0011] The distance between the axially outermost point of the main part of the carcass reinforcement layer and the radially innermost point A of the circle circumscribing the bead wire is measured on a tire mounted and inflated according to the nominal conditions. This measurement can be carried out, for example, using a tomography technique.

[0012] The other distances, in particular those measured from the radially innermost point A of the circle circumscribed by the bead, can also be measured using a tomography technique or are measured on a section of a tyre, the bead spacing of which is the same as when the tyre is mounted on the mounting rim recommended by ETRTO, the tyre therefore being neither mounted nor inflated.

[0013] The term "axially outward" is understood herein to mean that this is located outside the tire relative to the main part of the carcass reinforcement layer in a direction parallel to the natural axis of rotation of the tire.

[0014] Here, the first layer of rubber compound is a mixture of filling the space delimited by the main part of the carcass reinforcement layer and the turn-over of the carcass reinforcement layer called bead filler.

[0015] The second layer of rubber compound is a buffer element used to ensure the geometry of the turn-up of the carcass reinforcement layer, particularly at the coupling and decoupling zones between the main part and the turn-up of the carcass reinforcement layer.

[0016] Finally, the third layer of rubber compound is a protective rubber ensuring contact between the tire and the wheel during assembly.

[0017] Advantageously, the first layer of rubber compound being profiled, the turn-up of the carcass reinforcement layer and the main part of the carcass reinforcement layer are coupled radially outwards from a point C of the turn-up of the carcass reinforcement layer located at a distance of between 30 and 55%, of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point A of the circle circumscribed to the bead wire and the radiofrequency communication module is arranged radially outwards beyond point C.

[0018] This positioning of the communication module radially outside point C makes it possible to move the communication module away from the maximum bending zone of the bead which is located between the radially upper end of the bead wire, point B, and the coupling zone delimited by point C. Consequently, the mechanical stresses undergone by the communication module are less strong thanks to its radial positioning beyond point C. In addition, the first layer of rubber compound is profiled to ensure coupling and decoupling between the turn-up of the carcass reinforcement layer and the main part of the carcass reinforcement layer. As a result, the turn-up of the carcass reinforcement layer, which is thin by nature, follows this profile making it possible to position the communication module radially relative to the singular points of this profile easily.Thus, the accuracy of installation of the communication module on the turn-over of the carcass reinforcement layer is improved by the proximity of reference points constituted by the singular points of the profile of the first layer of rubber compound. It is therefore easy to locate point C to position the communication module radially external to it when producing the raw tire roughing.

[0019] According to a preferred embodiment, radially outwardly from point C of the turn-up of the carcass reinforcement layer, the turn-up of the carcass reinforcement layer and the main part of the carcass reinforcement layer are coupled over a length of between 15 and 65% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point A of the circle circumscribed to the bead wire, to then be decoupled by the first layer of rubber compound up to the end of the turn-up of the carcass reinforcement layer and the radiofrequency communication module is arranged radially opposite this coupling zone and the radiofrequency communication module is arranged radially opposite this coupling zone between the turn-up and the main part of the carcass reinforcement.

[0020] This positioning of the communication module is ideal as it distances the communication module from both the maximum flexion zone of the bead and the end of the turn-up of the carcass reinforcement layer. Thus, the presence of the communication module has no effect on the endurance of the tire but also preserves the physical integrity of the communication module while ensuring good radio communication performance. Finally, it is particularly easy to locate this coupling zone when producing the raw tire blank to position the communication module.

[0021] According to a preferred embodiment, the decoupling length is between 5 and 40% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point A of the circle circumscribed to the bead wire and preferably between 15 and 35% of said distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point A of the circle circumscribed to the bead wire.

[0022] Preferably according to the invention, the turn-up of the carcass reinforcement layer and the main part of the carcass reinforcement layer are coupled over a length of between 25 and 40% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point A of the circle circumscribed around the bead wire.

[0023] For the purposes of the invention, the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer are said to be coupled if the respective reinforcing elements of the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer are separated by a substantially constant thickness of rubber compound of at most 5 mm over a length greater than 15% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point A of the circle circumscribed to the bead wire. The thickness of rubber compound separating the respective reinforcing elements of the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer is measured in the direction normal to the reinforcing elements of the main part of the carcass reinforcement layer.Advantageously according to the invention, the respective reinforcing elements of the main part of the carcass reinforcement layer and of the turn-up of the carcass reinforcement layer are separated by a substantially constant thickness of rubber mixture of at most 3.5 mm and preferably they are separated by a substantially constant thickness of rubber mixture of at least 0.8 mm and more preferably by a substantially constant thickness of rubber mixture of at least 2.5 mm.

[0024] For the purposes of the invention, a substantially constant thickness of rubber mixture separating the respective reinforcing elements of the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer is a thickness which does not vary by more than 0.5 mm. The variations in thickness are then only due to creep phenomena during the manufacture and curing of the tire.

[0025] For the purposes of the invention, the first layer of rubber mixture may consist of several rubber mixtures whose stiffness properties and more specifically whose moduli of elasticity under tension at 10% elongation may vary. In the case of several rubber mixtures constituting the first layer, they advantageously form a stiffness gradient decreasing from the bead wire towards the radially outer end of said first layer.

[0026] According to a preferred embodiment of the invention, the crown reinforcement comprising at least one layer of reinforcing elements, the ratio of the radial distance between the axially outermost point of the main part of the carcass reinforcement layer and the radially outermost point of the nominal rim, i.e. the radially outermost point of the rim hook, to the radial distance between the axially outer end of the axially widest layer of reinforcing elements of the crown reinforcement and the radially outermost point of the nominal rim is less than or equal to 55%.

[0027] The radial distance between the axially outermost point of the main part of the carcass reinforcement layer and the radially outermost point of the nominal rim is measured on a tire mounted and inflated according to the nominal conditions. This measurement can be carried out, for example, using a tomography technique.

[0028] The radial distance between the axially outer end of the axially widest layer of crown reinforcement elements and the radially outermost point of the nominal rim may also be measured using a tomographic technique with the tire mounted and inflated to nominal conditions.

[0029] More preferably according to the invention, the ratio of the radial distance between the axially outermost point E of the main part of the carcass reinforcement layer and the radially outermost point of the nominal rim to the radial distance between the axially outer end of the axially widest layer of reinforcing elements of the crown reinforcement and the radially outermost point of the nominal rim is less than 53%.

[0030] The tests have shown that the tires thus produced according to the invention and whose mass is lower than that of tires of more usual design, comprising for example layers of additional reinforcement elements of the stiffener type, have performances in terms of endurance, and in particular in terms of endurance of the bead zones, at least as good as those of said tires of more usual design, or even superior.

[0031] Advantageously according to the invention, the radially inner end of the second layer of rubber mixture is radially between the radially outermost point of the circle circumscribed to the bead wire and the radially innermost point of the circle circumscribed to the bead wire. This positioning is determined on a section of a tire, the bead spacing of which is the same as when the tire is mounted on the mounting rim recommended by the ETRTO, the latter therefore being neither mounted nor inflated.

[0032] According to a preferred embodiment of the invention, the modulus of elasticity under tension at 10% elongation of the calendering layers of the carcass reinforcement layer is between 4 and 16 MPa and preferably between 8 and 12 MPa. These values ​​make it possible in particular to define the desired compromise between the endurance performance of the tire and its performance in terms of rolling resistance.

[0033] Preferably according to the invention, the modulus of elasticity under tension at 10% elongation of the first layer of rubber mixture is less than or equal to the modulus of elasticity under tension at 10% elongation of the calendering of the carcass reinforcement layer. This choice makes it possible in particular to concentrate the shear forces within the first layer of rubber mixture.

[0034] More preferably according to the invention, the modulus of elasticity under tension at 10% elongation of the first layer of rubber mixture is greater than 50% of the modulus of elasticity under tension at 10% elongation of the calendering of the carcass reinforcement layer and preferably is greater than 70% of the modulus of elasticity under tension at 10% elongation of the calendering of the carcass reinforcement layer. This choice makes it possible to maintain the shear forces within the first layer of rubber mixture while ensuring good endurance performance.

[0035] Advantageously according to the invention, the modulus of elasticity under tension at 10% elongation of the second layer of rubber compound is less than 150% of the modulus of elasticity under tension at 10% elongation of the calendering of the carcass reinforcement layer. According to this advantageous embodiment of the invention, the second layer of rubber compound provides sufficient rigidity to ensure good endurance performance of the tire when pressed on the rim hooks while ensuring satisfactory rolling resistance performance.

[0036] According to a preferred embodiment of the invention, to promote the compromise between endurance and rolling resistance performance, the modulus of elasticity under tension at 10% elongation of the first layer of rubber mixture is greater than or equal to the modulus of elasticity under tension at 10% elongation of the third layer of rubber mixture which is itself greater than or equal to the modulus of elasticity under tension at 10% elongation of the fourth layer of rubber mixture.

[0037] For the purposes of the invention, the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer are said to be decoupled if, radially outside the coupling zone, the thickness of the rubber mixture separating the respective reinforcing elements of the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer is greater than that of the coupling zone.The respective reinforcing elements of the main part of the carcass reinforcement layer and of the turn-up of the carcass reinforcement layer are then advantageously separated by a thickness of rubber mixture of between 3 and 8 mm, said thickness of rubber mixture being measured in the direction normal to the reinforcing elements of the main part of the carcass reinforcement layer between the respective reinforcing elements of the main part of the carcass reinforcement layer and of the turn-up of the carcass reinforcement layer. Preferably according to the invention, in the decoupling zone, the respective reinforcing elements of the main part of the carcass reinforcement layer and of the turn-up of the carcass reinforcement layer are separated by at most 6 mm and preferably they are separated by at least 4 mm.

[0038] According to an advantageous embodiment of the invention, the decoupling zone may consist of a first part, called a transition part, extending the coupling zone in which the thickness of the rubber mixture separating the respective reinforcing elements of the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer increases and a second, radially outermost part in which the thickness of the rubber mixture separating the respective reinforcing elements of the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer is substantially constant.

[0039] According to this variant embodiment of the invention, the increase in the thickness of the first layer of rubber mixture makes it possible to compensate for the reduction in tension in the reinforcing elements of the carcass reinforcement when approaching the end of its turn-up in order to absorb the shear stresses between the main part of the carcass reinforcement layer and its turn-up.

[0040] Advantageously, the decoupling length is between 5 and 40% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire and preferably between 15 and 35% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire.

[0041] According to a preferred embodiment of the invention, in any meridian plane, over a length of the turn-up of the carcass reinforcement layer delimited radially between the end of said turn-up of the carcass reinforcement layer and a point located at a distance from the radially innermost point of the circle circumscribed to the bead wire equal to 65% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire, any point of the turn-up of the carcass reinforcement layer is at a distance from the outer surface of the tire of less than 10 mm.More preferably, any point of the turn-up of the carcass reinforcement layer is at a distance from the outer surface of the tire of less than 10 mm over a length of the turn-up of the carcass reinforcement layer delimited radially between the end of said turn-up and a point located at a distance from the radially innermost point of the circle circumscribed to the bead wire equal to 50% of the distance between the end of the turn-up of the carcass reinforcement layer and the radially innermost point of the circle circumscribed to the bead wire.

[0042] Advantageously still according to the invention, in any meridian plane, over a radial distance greater than 4 mm, and preferably greater than 10 mm, starting radially outside the end of the turn-up of the carcass reinforcement layer and at a radial distance from the end of the turn-up of the carcass reinforcement layer equal to 2.5 times the diameter of a reinforcing element of the carcass reinforcement and extending radially outwards, the thickness, measured in the direction normal to the reinforcing elements of the turn-up of the carcass reinforcement layer at the end of the turn-up of the carcass reinforcement layer, of the fourth layer of rubber mixture forming the outer surface of a sidewall is substantially constant.

[0043] Advantageously still according to the invention, in any meridian plane, over a radial distance greater than 4 mm, and preferably greater than 10 mm, starting radially inside the end of the turn-up of the carcass reinforcement layer and at a radial distance from the end of the turn-up of the carcass reinforcement layer equal to 2.5 times the diameter of a reinforcing element of the carcass reinforcement and extending radially inwards, the thickness, measured in the direction normal to the reinforcing elements of the turn-up of the carcass reinforcement layer at the end of the turn-up of the carcass reinforcement layer, of the fourth layer of rubber mixture forming the outer surface of a sidewall is substantially constant.

[0044] For the purposes of the invention, the expression a substantially constant thickness means that it does not vary by more than 0.5 mm. These variations in thickness are only due to creep phenomena during the manufacture and curing of the tire.

[0045] The fourth layer of rubber mixture thus produced according to the invention appears to contribute to the better positioning of the first layer of rubber mixture and to its installation to ensure the coupling and possibly the decoupling of the main part of the carcass reinforcement layer and the turning of the carcass reinforcement layer.

[0046] According to an advantageous embodiment of the invention, in any meridian plane, in each bead, the tire comprises a containment reinforcement surrounding the bead wire and a volume of rubber mixture directly in contact with the bead wire.

[0047] Such a containment reinforcement makes it possible, during use of the tire, to limit changes in the shape of the bead and thus to maintain satisfactory performance, particularly in terms of endurance. Indeed, the tire according to the invention, the structure of which leads to its lightening, could, in certain cases of use or types of rolling, lead to a geometric evolution in the bead area that is potentially detrimental to the tire's endurance performance. The presence of a containment reinforcement such as proposed makes it possible to delay or even prevent such a geometric evolution. Advantageously still according to the invention, the containment reinforcement is made up of a layer of textile reinforcing elements of the aliphatic polyamide type.

[0048] Advantageously according to the invention, the rods are packet rods, that is to say rods formed from an assembly of gummed wires wound around a shape, preferably hexagonal in shape.

[0049] According to one embodiment of the invention, in particular to further improve the tire's endurance performance, the carcass reinforcement is formed of cables whose structure is heavily penetrated by rubber compounds. These may, for example, be cables whose construction makes it possible to increase their penetrability by the rubber compounds. They may also be cables into which rubber compounds are inserted during the manufacture of the cables themselves. These are, for example, cables with at least two layers, at least one internal layer being sheathed with a layer consisting of a non-crosslinkable, crosslinkable or crosslinked rubber composition, preferably based on at least one diene elastomer.

[0050] According to an alternative embodiment of the invention, the crown reinforcement of the tire is formed from at least two working crown layers of inextensible reinforcing elements, crossed from one layer to the other making angles of between 10° and 45° with the circumferential direction.

[0051] According to other variant embodiments of the invention, the crown reinforcement also comprises at least one layer of circumferential reinforcing elements.

[0052] A preferred embodiment of the invention also provides that the crown reinforcement is completed radially on the outside by at least one additional layer, called a protective layer, of so-called elastic reinforcing elements, oriented relative to the circumferential direction with an angle of between 10° and 45° and in the same direction as the angle formed by the inextensible elements of the working layer which is radially adjacent to it.

[0053] The protective layer may have an axial width less than the axial width of the narrowest working layer. Said protective layer may also have an axial width greater than the axial width of the narrowest working layer, such that it covers the edges of the narrowest working layer and, in the case of the radially upper layer being the narrowest, such that it is coupled, in the axial extension of the additional reinforcement, with the widest working crown layer over an axial width, to then be, axially on the outside, decoupled from said widest working layer by profiles of thickness at least equal to 2 mm.The protective layer formed of elastic reinforcing elements may, in the case cited above, be on the one hand possibly decoupled from the edges of said narrower working layer by profiles of thickness substantially less than the thickness of the profiles separating the edges of the two working layers, and on the other hand have an axial width less than or greater than the axial width of the widest top layer.

[0054] According to any of the embodiments of the invention mentioned above, the crown reinforcement can also be supplemented, radially inside between the carcass reinforcement and the radially inner working layer closest to said carcass reinforcement, by a triangulation layer of inextensible metallic steel reinforcing elements making, with the circumferential direction, an angle greater than 60° and in the same direction as that of the angle formed by the reinforcing elements of the layer radially closest to the carcass reinforcement.

[0055] Preferably, the communication module consists of the radio frequency transponder encapsulated in a mass of electrically insulating coating rubber. For example, the radio frequency transponder may be sandwiched between two plates of insulating coating rubber.

[0056] Advantageously, the extension modulus of the coating rubber mass is less than or equal to the extension modulus of the adjacent rubber mixtures. This limits the stresses at the interfaces between the communication modulus and the adjacent rubber mixtures.

[0057] Similarly, advantageously the relative dielectric constant of the coating rubber mass is lower than the relative dielectric constant of the adjacent rubber mixtures, this facilitates radio frequency communication between the module and an external reader.

[0058] Preferably, the transponder comprising an electronic chip coupled to a radiating antenna defining a first longitudinal axis, this first longitudinal axis is oriented circumferentially.

[0059] This orientation is perpendicular to the wires of the carcass ply and is very favorable for the mechanical strength of the transponder as well as for the reading quality of the transducer.

[0060] According to a first embodiment of the communication module, the radiating antenna comprising two sections of helical antennas, the electronic chip is galvanically connected to the two sections of helical antennas.

[0061] According to a second embodiment of the communication module, the radiofrequency transponder of the communication module further comprises a primary antenna electrically connected to the electronic chip, the primary antenna is inductively coupled to the radiating antenna, and the radiating antenna is a dipole antenna consisting of a single-strand helical spring defining the first longitudinal axis.

[0062] The primary antenna may be a coil having at least one turn defining a second longitudinal axis which is circumscribed in a cylinder whose axis of revolution is parallel to the second longitudinal axis and whose diameter is between one third and three times, preferably between one half and two times, the average diameter of the helical spring of the radiating antenna.

[0063] According to a very preferred embodiment, the primary antenna is arranged inside the single-strand helical spring of the radiating antenna. Description of Figures

[0064] The various objects of the invention will be better understood by means of the detailed description which follows, in conjunction with the appended figures in which the same reference numbers designate identical parts throughout, and in which: there Figure 1 illustrates a meridian view of a diagram of a tire according to an embodiment of the invention; the Figure 2 , presents an enlarged schematic representation of the bead area of ​​the tire of the Figure 1 ; there Figure 3 has a standard radio frequency transponder; Figure 4 presents a schematic exploded view of a communication module; the Figure 5 shows a perspective view of a radiofrequency transponder according to an embodiment of the invention in a configuration where the electronic part is located inside the radiating antenna; the Figure 6 shows a perspective view of a radiofrequency transponder according to the invention in a configuration where the electronic part is located outside the radiating antenna; and the Figure 7 shows a perspective view of the electronic part of a radio frequency transponder in a configuration where the electronic part is located inside the radiating antenna.

[0065] Figures are not drawn to scale to simplify understanding. Detailed description of the invention

[0066] In the following, the terms "rubber compound", "rubber mixture", "rubber" and "mixture" are used interchangeably to identify rubber constituents of the tire.

[0067] Cables are said to be inextensible when, under a tensile force equal to 10% of the breaking force, the said cables exhibit a relative elongation of at most 0.2%.

[0068] Cables are said to be elastic when said cables exhibit, under a tensile force equal to the breaking load, a relative elongation at least equal to 3% with a maximum tangent modulus less than 150 GPa.

[0069] Circumferential reinforcing elements are reinforcing elements which make angles with the circumferential direction in the range +2.5°, -2.5° around 0°.

[0070] The circumferential direction of the tire, or longitudinal direction, is the direction corresponding to the periphery of the tire and defined by the rolling direction of the tire.

[0071] The transverse or axial direction of the tire is parallel to the tire's axis of rotation.

[0072] The radial direction is a direction intersecting the tire's axis of rotation and perpendicular to it.

[0073] The tire's axis of rotation is the axis around which it rotates during normal use.

[0074] A radial or meridian plane is a plane that contains the tire's axis of rotation.

[0075] The circumferential median plane, or equatorial plane, is a plane perpendicular to the tire's axis of rotation and which divides the tire into two halves.

[0076] For metal wires or cables, the measurements of breaking force (maximum load in N), breaking strength (in MPa), elongation at break (total elongation in %) and modulus (in GPa) are carried out in tension according to the ISO 6892 standard of 1984.

[0077] As regards rubber compositions, the modulus measurements are carried out in tension according to the AFNOR-NFT-46002 standard of September 1988: the nominal secant modulus (or apparent stress, in MPa) is measured in second elongation (i.e., after an accommodation cycle) at 10% elongation (normal temperature and humidity conditions according to the AFNOR-NFT-40101 standard of December 1979).

[0078] There Figure 1represents only a half-view of a tire that extends symmetrically about the circumferential median plane, or equatorial plane, of a tire.

[0079] On the Figure 1 , the tire 1 is of dimension 12 R 22.5. The tire 1 comprises a radial carcass reinforcement 2 anchored in two beads 3. The carcass reinforcement 2 is hooped to the top of the tire by a crown reinforcement 5, itself topped with a tread 6.

[0080] The carcass reinforcement 2, formed from a single layer of metal cables, is wound in each of the beads 3 around a bead wire 4 and forms in each of the beads 3 a turn-up of the carcass reinforcement layer 7 having an end 8.

[0081] The carcass reinforcement 2 consists of reinforcing elements between two calendering layers whose modulus of elasticity under tension at 10% elongation is equal to 9.8 MPa.

[0082] The reinforcing elements of the carcass reinforcement 2 are 19.18 cables with an elongation at break of 2.5%.

[0083] The carcass reinforcement cords of the tire 1 are metal cords with 1+6+12 structure layers, not banded, consisting of a central core formed by one wire, an intermediate layer formed by six wires and an outer layer formed by twelve wires.

[0084] There Figure 1 illustrates the tire mounted on its nominal rim J; the axially outermost point E of the main part of the carcass reinforcement layer 2 is thus determined with the tire inflated to its nominal pressure, for example by tomography.

[0085] There Figure 2illustrates in an enlarged manner a schematic cross-sectional representation of a bead 3 of the tire in which we find a part of the carcass reinforcement layer 2 wound around a bead wire 4 to form a turn-up 7 with an end 8.

[0086] On this Figure 2 , the circle T circumscribed to the bead 4 is materialized and the radially innermost point A of said circle T appears. This point A is defined on a radial section of the tire, the bead spacing of which is the same as when the tire is mounted on the mounting rim recommended by the ETRTO, the latter not being mounted on a rim.

[0087] We also determine the radially outermost point B of the circle T.

[0088] The distance d E between point E and point A is equal to 128 mm.

[0089] The distance d R between point 8 and point A is equal to 90 mm.

[0090] The ratio of the distance d R to the distance d E is equal to 70% and therefore between 45 and 90%.

[0091] The radial distance d CJ between the axially outermost point E of the main part of the carcass reinforcement layer and the radially outermost point of the nominal rim is equal to 108.2 mm.

[0092] The radial distance d SJ between the axially outer end of the axially widest layer of reinforcing elements of the crown reinforcement and the radially outermost point of the nominal rim is equal to 206.7 mm.

[0093] The ratio of the distance d CJ to the distance d SJ is equal to 52.3% and therefore less than 53%.

[0094] The turn-up 7 of the carcass reinforcement layer is coupled to the main part of the carcass reinforcement layer 2 from point C, such that the distance d C between point C and point A is equal to 37 mm.

[0095] The ratio of the distance d C to the distance d R is equal to 41% and therefore between 30 and 55%.

[0096] The turn-up 7 of the carcass reinforcement layer is then decoupled from the main part of the carcass reinforcement layer 2 from point D, such that the distance d D between point D and point A is equal to 66 mm and such that the coupling length between point C and point D is equal to 29 mm and therefore between 25 and 40% of the distance d R . The coupling length is measured along the straight line passing through points C and D.

[0097] The coupling thickness between the main part of the carcass reinforcement layer 2 and the turn-up 7 of the carcass reinforcement layer, measured in the direction normal to the reinforcing elements of the main part of the carcass reinforcement layer 2 between the respective reinforcing elements of the main part of the carcass reinforcement layer and the turn-up of the carcass reinforcement layer 2, is substantially constant and equal to 2.9 mm.

[0098] The decoupling length between point D and point 8 is equal to 21 mm and therefore between 15 and 35% of the distance d R . The decoupling length is measured along the straight line passing through points D and 8.

[0099] The turn-up 7 of the carcass reinforcement layer 2 is separated from the main part of the carcass reinforcement layer 2 by a first layer of rubber mixture 9, having a radially outer end 10 at a distance d 10 from point A equal to 117 mm. The first layer of rubber mixture 9 has a modulus of elasticity under tension at 10% elongation equal to 7.8 MPa and therefore lower than the modulus of elasticity under tension at 10% elongation of the calendering layers of the carcass reinforcement 2.

[0100] The first layer of rubber mixture 9 is profiled to bear on the bead wire 4 and ensure coupling and decoupling between the turn-up of the carcass reinforcement layer 7 and the main part of the carcass reinforcement layer 2.

[0101] Axially outside the turn-up 7 of the carcass reinforcement layer is shown the second layer of rubber mixture 11, the radially outer end 12 of which is radially inside the end 8 of the turn-up 7 of the carcass reinforcement layer. According to another embodiment not shown, the radially outer end of the second layer of rubber mixture is radially outside the end 8 of the turn-up 7 of the carcass reinforcement layer.

[0102] The radially inner end 13 of the second layer of rubber mixture 11 is radially between points A and B, respectively radially the innermost and radially the outermost of the circle circumscribed to the bead wire.

[0103] The second layer of rubber mixture 11 has a modulus of elasticity under tension at 10% elongation equal to 12.5 MPa and therefore greater than the modulus of elasticity under tension at 10% elongation of the calendering layers of the carcass reinforcement 2.

[0104] In contact with the second layer of rubber mixture 11 and radially under the bead wire, there is the third layer of rubber mixture 14, the axially outermost end 15 of which is radially inside the end 12 of the second layer of rubber mixture 11.

[0105] The third layer of rubber mixture 14 has a modulus of elasticity under tension at 10% elongation equal to 7.1 MPa.

[0106] Axially in contact with the first layer of rubber mixture 9, the second layer of rubber mixture 11, and the third layer of rubber mixture 14, is the fourth layer of rubber mixture 16. The radially inner end 17 of the fourth layer of rubber mixture 16 is radially inner to the end 15 of the third layer of rubber mixture 14.

[0107] The fourth layer of rubber mixture 16 has a modulus of elasticity under tension at 10% elongation equal to 3.1 MPa.

[0108] In areas located on either side of the end 8 of the turn-up 7 of the carcass reinforcement layer, the profile of the fourth layer of rubber mix 16 is such that said fourth layer of rubber mix 16 has a thickness, measured in the direction normal to the reinforcing elements of the carcass reinforcement 2 at the end 8 of the turn-up 7, substantially constant and equal to 3.3 mm, over two radial lengths of approximately 5 mm from each of the two points located on either side of the end 8 at distances from said end 8 equal to 2.5 mm corresponding to more than 2.5 times the diameter of the carcass reinforcement cables, the latter being equal to 0.9 mm.

[0109] The bead 3 also comprises a radiofrequency communication module 20 arranged axially at the interface between the upturn of the carcass reinforcement 7 and the second layer of rubber compound 11. This communication module 20 is placed radially at the coupling zone between the main part 2 of the carcass reinforcement and the upturn 7 of this carcass reinforcement, that is to say between the two points C and D of the Figure 2 . This position mechanically protects the radiofrequency transponder of the communication module well and the applicant has found experimentally that the close presence of the metal wires of the turn-up 7 of the carcass reinforcement 2 did not prevent good communication with an external reader. The communication module 20 is preferably arranged substantially in the middle of the coupling zone, between C and D. As indicated on the Figure 2, the communication module is placed in the tire so that its dipole-type radiofrequency antenna is positioned circumferentially. Thus, the radiofrequency antenna is perpendicular to the reinforcing elements of the radial-type carcass reinforcement layer. Thus, the radiofrequency antenna then rests on a large number of reinforcing elements, which improves its mechanical stability. In addition, although the reinforcing elements may be metallic, the relative perpendicularity of the orientation of the radiofrequency antenna with respect to the metallic reinforcing elements minimally disrupts the radiofrequency operation of the antenna.

[0110] There Figure 4shows an exploded view of a communication module 20. This module 20 comprises a radiofrequency transponder 30 embedded between two layers 22a and 22b of an unvulcanized electrically insulating rubber compound. The thickness of each layer is of the order of 1 mm, the length of the order of 50 to 70 mm and its width of the order of 10 to 20 mm. Such a communication module is a semi-finished product capable of being integrated into the structure of the tire 1 during the manufacture thereof.

[0111] The position chosen for placing the communication module 20 is particularly favorable. The unvulcanized semi-finished product is deposited on the surface of the turn-up 7 of the carcass reinforcement 2 during the manufacture of the tire before the installation of a complex combining the second, third and fourth layers of rubber mixture.

[0112] The rubber mixture 22 for coating the radio frequency transponder 30 contains 100 pce (parts per 100 parts of elastomer by mass) of polymer such as EPDM (ethylene propylene diene monomer rubber), butyl rubber, neoprene or diene elastomer such as SBR (styrene-butadiene rubber), polybutadiene, natural rubber, or polyisoprene.

[0113] The mixture may contain fillers such as silica, carbon black, chalk, kaolin: with a silica type filler at a maximum rate of 50 pce, with a carbon black type filler of ASTM grade greater than 700, at a rate less than 50 pce; with a carbon black type filler of grade less than or equal to 500, at a maximum rate of 20 pce. It is possible to add or replace these fillers with chalk or kaolin.

[0114] Such rates and types of charges make it possible to guarantee a relative permittivity lower than 6.5, in particular at a frequency of 915 MHz.

[0115] The cured stiffness of the coating mixture is preferably less than or close to that of adjacent rubber mixtures.

[0116] In a first embodiment, the radiofrequency transponder of the communication module 20 is a standard radiofrequency transponder, as shown in FIG. Figure 3 and described in document WO 2012 / 030321 A1. This transponder 100 comprises an electronic chip 120 fixed on a support or PCB (printed circuit board) 102 and galvanically connected via the conductive tracks 104 and the solders 130 to two half-antennas 110 and 112. The antennas are helical springs with a steel wire core. The electronic part and at least part of the antennas are embedded in an insulating rubber mixture 150. The antennas define an axis of symmetry 39.

[0117] The radio frequency transponder 30 of the communication module 20 as shown in the Figure 4corresponds to a second embodiment of the communication module 20 which will now be described.

[0118] The radiofrequency transponder 30 according to this second embodiment of the communication module 20 comprises an electronic part 32 and a radiating antenna 31 capable of communicating with an external radiofrequency reader. It further comprises (see Figure 7 ) a primary antenna 34 electrically connected to the electronic chip 36 and inductively coupled to the radiating antenna 31. The radiating antenna is a dipole antenna consisting of a single-strand helical spring defining a first longitudinal axis.

[0119] There Figure 5has a radiofrequency transponder 30 in a configuration where the electronic part 32 is located inside the radiating antenna 31. The geometric shape of the electronic part 32 is circumscribed in a cylinder whose diameter is less than or equal to the internal diameter of the helical spring. This makes it easier to insert the electronic part 32 into the radiating antenna 31. The median plane of the primary antenna is located in the central zone of the radiating antenna and substantially superimposed on the median plane of the radiating antenna.

[0120] There Figure 6has a radiofrequency transponder 30 in a configuration where the electronic part 32 is located outside the radiating antenna 31. The geometric shape of the electronic part 32 has a cylindrical cavity 38 whose diameter is greater than or equal to the external diameter of the radiating antenna 31. The threading of the radiating antenna 31 into the cylindrical cavity 38 of the electronic part is thus facilitated. The median plane of the primary antenna is located in the central zone of the radiating antenna and substantially in the median plane of the radiating antenna 31.

[0121] There Figure 7shows the electronic part 32 of a radiofrequency transponder 30 intended for a configuration where the electronic part 32 is located inside the radiating antenna 31. The electronic part 32 comprises an electronic chip 36 and a primary antenna 34 electrically connected to the electronic chip 36 via a printed circuit 40. The primary antenna is here constituted by a CMS micro coil (acronym for Surface Mounted Component). The electrical connection between the components on the printed circuit is made using copper tracks 37 terminated by copper pads 41. The electrical connection of the components on the printed circuit is made using the technique known as “wire bonding” by gold wires 42 between the component and the pads 41.The assembly consisting of the printed circuit 40, the electronic chip 36 and the primary antenna 34 is embedded in a rigid mass 43 made of electrically insulating high-temperature epoxy resin constituting the electronic part 32 of the radiofrequency transponder 30.

[0122] This 30 radiofrequency transponder has the advantage of being much more mechanically resistant than conventional transponders.

Claims

1. Tyre (1) intended to be mounted on a drop-centre rim (J) (15° drop centre), comprising a radial carcass reinforcement (2), made up of a single carcass reinforcement layer formed of reinforcing elements inserted between two skim layers of rubber compound, said tyre (1) comprising a crown reinforcement (5), itself radially capped by a tread (6), said tread (6) being connected to two beads (3) by two sidewalls, the layer of reinforcing elements of the carcass reinforcement (2) being anchored in each of the beads (3) by being turned up around a bead wire (4) to form a main part of the carcass reinforcement layer (2), extending from one bead wire (4) to the other, and a turn-up (7) of the carcass reinforcement layer (2) in each of the beads (3), said turn-up (7) of the carcass reinforcement layer (2) being separated from the main part of the carcass reinforcement layer (2) by a first layer of rubber compound (9) extending radially from the bead wire (4) to beyond the end (8) of the turn-up (7) of the carcass reinforcement layer (2), and said turn-up (7) of the carcass reinforcement layer (2) being, axially towards the outside, in contact with a second layer of rubber compound (11), itself at least in contact with a third layer of rubber compound (14) that forms the exterior surface of the tyre (1) in the region of the bead, said third layer of rubber compound (14) notably being intended to come into contact with the rim (J), said third layer of rubber compound (14) being, radially towards the outside, in contact with a fourth layer of rubber compound (16) that forms the exterior surface of said sidewall, in meridian section of said tyre: - the distance (dR) between the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the radially innermost point (A) of the circle (T) circumscribed on the bead wire (4) being between 45 and 90% of the distance (dE) between the axially outermost point (E) of the main part of the carcass reinforcement layer (2) and the radially innermost point (A) of the circle (T) circumscribed on the bead wire (4), - the turn-up (7) of the carcass reinforcement layer (2) and the main part of the carcass reinforcement layer (2) being the only layers of reinforcing elements of which the elongation at break is less than 6% that are present in a sidewall region making up at least 90% of the region comprised between the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the radially outermost point (B) of the bead wire (4), and the tyre being characterized in that the radiofrequency communication module (20) is positioned in the bead (3) at the interface between the turn-up (7) of the carcass reinforcement layer (2) and the second layer of rubber compound (11).

2. Tyre (1) according to Claim 1, wherein, with the first layer of rubber compound (9) being profiled, the turn-up (7) of the carcass reinforcement layer (2) and the main part of the carcass reinforcement layer (2) are coupled radially towards the outside starting from a point C on the turn-up (7) of the carcass reinforcement layer (2), which point is situated at a distance between 30 and 55% of the distance (dR) between the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the radially innermost point (A) of the circle (T) circumscribed on the bead wire (4),that is to say the respective reinforcing elements of the main part of the carcass reinforcement layer (2) and of the turn-up (7) of the carcass reinforcement layer are separated by a thickness of rubber compound not varying by more than 0.5 millimeters and at most 5 mm along a length greater than 15% of the distance (dR) and wherein the radiofrequency communication module (20) is positioned radially on the outside beyond the point C.

3. Tyre (1) according to Claim 2, wherein, radially towards the outside, starting from said point C of the turn-up (7) of the carcass reinforcement layer (2), the turn-up (7) of the carcass reinforcement layer (2) and the main part of the carcass reinforcement layer (2) are coupled along a length of between 15 and 65% of the distance (dR) between the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the radially innermost point A of the circle (T) circumscribed on the bead wire (4), and are then decoupled by the first layer of rubber compound (9) as far as the end (8) of the turn-up (7) of the carcass reinforcement layer (2), that is to say the thickness of rubber compound (9) separating the respective reinforcing elements of the main part of (2) the carcass reinforcement layer and of the turn-up (7) of the carcass reinforcement layer is greater than the thickness of said rubber compound (9) of the coupling region and wherein the radiofrequency communication module (20) is placed radially facing said region of coupling between the turn-up (7) and the main part of the carcass reinforcement (2).

4. Tyre (1) according to Claim 3, wherein the decoupling length, that is to say the length of the straight line passing through the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the point D which is the most outermost end of the coupling region from the bead wire (4), is between 5 and 40% of thedistance (dR) between the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the radially innermost point (A) of the circle (T) circumscribed on the bead wire (4), and is preferably between 15 and 35% of the distance (dR) between the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the radially innermost point (A) of the circle (T) circumscribed on the bead wire (4).

5. Tyre (1) according to one of Claims 2 to 4, wherein the turn-up (7) of the carcass reinforcement layer (2) and the main part of the carcass reinforcement layer (2) are coupled along a length of between 25 and 40% of the distance (dR) between the end (8) of the turn-up (7) of the carcass reinforcement layer (2) and the radially innermost point (A) of the circle (T) circumscribed on the bead wire (4).

6. Tyre (1) according to one of Claims 2 to 5, wherein, in the coupling region, the thickness of the first layer of rubber compound (9) is substantially constant and between 0.8 and 5 mm, and preferably between 2.5 and 3.5 mm.

7. Tyre (1) according to any one of the preceding claims, wherein the radially inner end (13) of the second layer of rubber compound (11) is radially comprised between the radially outermost point (B) of the circle (T) circumscribed on the bead wire (4) and the radially innermost point (A) of the circle (T) circumscribed on the bead wire (4).

8. Tyre (1) according to any one of the preceding claims, wherein the tensile elastic modulus at 10% elongation of the skim layers of the carcass reinforcement layer (2) is between 4 and 16 MPa and preferably between 8 and 12 MPa.

9. Tyre (1) according to one of the preceding claims, wherein the tensile elastic modulus at 10% elongation of the first layer of rubber compound (9) is less than or equal to the tensile elastic modulus at 10% elongation of the skim rubber of the carcass reinforcement layer (2).

10. Tyre (1) according to one of the preceding claims, wherein the tensile elastic modulus at 10% elongation of the first layer of rubber compound (9) is greater than 50% of the tensile elastic modulus at 10% elongation of the skim rubber of the carcass reinforcement layer (2) and preferably is greater than 70% of the tensile elastic modulus at 10% elongation of the skim rubber of the carcass reinforcement layer (2).

11. Tyre (1) according to one of the preceding claims, wherein the tensile elastic modulus at 10% elongation of the second layer of rubber compound (11) is less than 150% of the tensile elastic modulus at 10% elongation of the skim rubber of the carcass reinforcement layer (2).

12. Tyre (1) according to any one of the preceding claims, wherein the communication module (20) consists of said radiofrequency transponder (30) encapsulated in an electrically insulating encapsulating rubber mass (22).

13. Tyre (1) according to the preceding claim wherein the radiofrequency transponder (30) comprising a electronic chip (36) coupled with a radiating antenna (31) defining a first longitudinal axis, said first longitudinal axis is oriented circumferentially.

14. Tyre (1) according to the preceding claim, wherein, with said radiating antenna (31) comprising two helical antenna segments, said electronic chip (36) is galvanically connected to said two helical antenna segments.

15. Tyre (1) according to Claim 13, wherein the radiofrequency transponder (30) of the communication module (20) additionally comprises a primary antenna (34) electrically connected to the electronic chip (36), wherein the primary antenna (34) is inductively coupled to the radiating antenna (31), and wherein the radiating antenna (31) is a dipole antenna consisting of a single-strand helical spring defining said first longitudinal axis.