WO2022148922A1

WO2022148922A1 - Tyre comprising a bracing ply having a hydrophobic weft and a reduced decoupling thickness

Info

Publication number: WO2022148922A1
Application number: PCT/FR2022/050003
Authority: WO
Inventors: Arnaud Delbast; Laure GALLARD; Pascal BONNAMAIN
Original assignee: Compagnie Generale Des Etablissements Michelin
Priority date: 2021-01-07
Filing date: 2022-01-03
Publication date: 2022-07-14
Also published as: CN116685477A; FR3118606A1; CA3203677A1; EP4274744A1

Abstract

The tyre (10) comprises a crown reinforcement (16) comprising a working reinforcement (20) that includes a radially outermost working ply (26) and a bracing reinforcement (22) comprising a plurality of filamentary textile bracing elements (220) wound radially in a helix around the working reinforcement (20) and linked to one another by one or more filamentary weft element(s) (42). In the axially central portion (P0) of the crown (12), the mean radial distance E2 between the filamentary textile bracing elements (220) and the metal wire working reinforcements (260) is such that E2 ≤ 0.40 mm. Each filamentary weft element (42) comprises multiple textile monofilaments and/or multiple textile fibres selected from among the synthetic organic polymer monofilaments and fibres, the synthetic inorganic polymer monofilaments and fibres and the assemblies of these monofilaments and fibres.

Description

Tire comprising a hooping layer with a hydrophobic weft and reduced decoupling thickness

[001] The present invention relates to a tire. By tire is meant a tire intended to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure greater than atmospheric pressure. A tire according to the invention has a structure of substantially toroidal shape of revolution around a main axis of the tire.

[002] The state of the art is known for tires for passenger vehicles comprising a crown comprising a tread as well as a crown reinforcement. The crown reinforcement conventionally comprises a hooping reinforcement and a working reinforcement. The hooping reinforcement is arranged radially outside the working reinforcement and radially inside the tread.

[003] The working reinforcement comprises a radially inner working layer and a radially outer working layer arranged radially outside the radially inner working layer. Each radially inner and outer working layer is delimited axially by two axial edges of said working layer and comprises metallic working wire reinforcement elements extending axially from one axial edge to the other axial edge of said working layer substantially parallel to each other.

[004] The hooping reinforcement is delimited axially by two axial edges and comprises a strip wound helically over several circumferential turns so as to extend axially between the axial edges of the hooping reinforcement. The strip comprises several textile hooping wire reinforcement elements substantially parallel to each other extending along a main hooping direction.

[005] On the one hand, it has been noted that, despite their excellent performance, these tires showed, after running in very aggressive conditions and in the presence of corrosive agents, pockets of oxidation on the working reinforcement, in particular on the radially outer working layer. Such very aggressive conditions are encountered in particular when rolling the tires on stony roads. Oxidation pockets, if they do not threaten the safety of use, can generate vibrations for the driver of the vehicle which constitutes a discomfort of comfort which it is desirable to remove.

[006] On the other hand, in order to reduce the mass of the tires as well as their rolling resistance and therefore their environmental footprint, it is sought to reduce the quantity of materials used, in particular in the crown of the tires. Nevertheless, by reducing the quantities of materials used in the crown, it is foreseeable that we would then expose the hooping reinforcement and the working reinforcement to increased penetration of corrosive agents and therefore to the faster formation and greater number of oxidation pockets previously described. One would then obtain, admittedly, lighter tires but with an amplified vibratory discomfort which is not desirable.

[007] The object of the invention is to obtain a tire with a better compromise between the vibrational discomfort generated by the pockets of oxidation and the mass of the tire, and consequently, its rolling resistance.

[008] To this end, the subject of the invention is a tire comprising a crown comprising a tread carrying a tread surface, the crown comprising an axially central part extending over an axial width equal to 50% of the axial width of the running surface and axially centered on the median plane of the tire, the axially central part of the tread comprising at least one deepest cutout of the axially central part of the tread, the crown comprising a crown reinforcement including:

- a working reinforcement comprising at least one radially outermost working layer of the working reinforcement, the radially outermost working layer comprising metallic working wire reinforcement elements,

- a hooping reinforcement comprising several textile hooping wire reinforcement elements wound helically radially around the working reinforcement and connected to each other by one or more weft wire element(s), the hooping being arranged radially outside the working reinforcement and radially inside the tread, tire in which, in the axially central part of the crown, the mean radial distance E2 between:

- the radially inner surface passing through the radially innermost points of the most radially inner textile hooping wire reinforcement elements among the textile hooping wire reinforcement elements,

- the radially outer surface passing through the radially outermost points of the metallic working wire reinforcement elements of the radially outermost working layer of the working reinforcement, is such that E2 < 0.40 mm, and pneumatic in which, the or at least one of the filamentary weft element(s) comprises several textile monofilaments and/or several textile fibers chosen from monofilaments and organic polymeric synthetic fibers, monofilaments and inorganic polymeric synthetic fibers and assemblies of these monofilaments and fibers.

[009] In order to achieve the object of the invention, the inventors at the origin of the invention had to demonstrate the mechanism leading to the formation of oxidation pockets. Thus, the inventors have observed that the very aggressive conditions encountered when rolling the tire on stony pavement are such that the pebbles coating the pavement form indenters attacking the tread of the tire and go so far as to perforate the latter and reach the vertex frame. Once these aggressions have been suffered by the tread, the corrosive agents, in particular water and salt, first penetrate the crown reinforcement via the hooping reinforcement. Within the hooping reinforcement of tires of the state of the art, it has been observed that the corrosive agents were, in a second stage, conducted into the hooping reinforcement not by the wired textile hooping reinforcement elements. but by the weft wire elements connecting to each other the textile hooping wire reinforcement elements. This conduction of corrosive agents is made possible by the very nature of these weft wire elements which comprise an assembly comprising cotton monofilaments. The use of cotton was, until the discovery of the inventors, guided only by the relatively low cost of cotton and by the fact that such weft wire elements were useful only during the manufacturing process of the reinforcement of shrinking described below and had no effect on the formation of oxidation pockets.

[010] Indeed, in the tires of the state of the art, such weft wire elements are substantially parallel to each other in a main weft direction that is not collinear with the main hooping direction. The main weft direction and the main hooping direction are substantially perpendicular. Such weft wire elements are used during the method of manufacturing the strip during which, during a step of manufacturing a very wide fabric, the wire reinforcing hooping elements are arranged substantially parallel to each other textiles and they are connected together by one or more weft wire elements, each weft wire element extending over the entire width of the wide fabric. During a subsequent sizing step, the textile hooping wire reinforcing elements and the weft wire elements are coated with one or more layers of one or more adhesive compositions, then the fabric is heat treated to a high width previously obtained so as to obtain a large width fabric glued. Then, during a subsequent calendering step, the bonded wide-width fabric is embedded in an elastomeric matrix so as to obtain a wide-width calendered fabric. Next, during a cutting step, the large-width calendered fabric is cut so as to obtain several small-width strips in which the textile hooping wire reinforcing elements extend in a direction substantially parallel to the direction of the largest strip length.

[011] Thus, as explained above, until the discovery of the inventors, it was thought that the weft wire elements had the sole function of maintaining the textile hooping wire reinforcement elements relative to each other during the different gluing, calendering and die-cutting stages.

[012] Once discovered the essential role of the weft wire elements in the formation of oxidation pockets in the tires of the state of the art, the inventors therefore proposed to eliminate the conduction means formed by the weft wire elements. cotton weft and, in accordance with the invention, identified that the weft wire element(s) comprising as little as possible of monofilaments and fibers that conduct corrosive agents made it possible to limit the formation of oxidation pockets. Thus, the invention teaches the use of monofilaments and/or organic and/or inorganic synthetic fibers which, by their very nature, do not or very little conduct water and no or very little corrosive agents and in in any case, much less than cotton.

[013] Indeed, monofilaments and/or organic and/or inorganic synthetic fibers have a relatively low rate of moisture uptake. Thus, the or at least one of the filamentary weft element(s) has a moisture absorption rate typically strictly less than 5.0%, preferably less than or equal to 3.0% and even more preferably less or equal to 2.0%. The moisture pick-up rate is measured in accordance with ASTM D 885/D 885MA of January 2010 (paragraph 10) and is defined as the ratio of the mass of water contained in the weft wire element to the dry mass of the weft wire element, expressed as a percentage and is equal to [(W - M)/M] x 100 where W is the mass, in grams, of the weft wire element subjected to a temperature of 23°C ±2°C under 50%±10% relative humidity for 48 hours according to standard IS023529:2016, and M is the mass, in grams, of the weft wire element after drying in the oven.

[014] In accordance with the invention, the textile hooping wire reinforcement elements are connected to each other by one or more weft wire element(s). Thus, the weft wire element(s) are interlaced with the textile hooping wire reinforcement elements in contact with the textile hooping wire reinforcement elements so as to maintain each textile hooping wire reinforcement element at a given distance from the element(s) of textile hooping wire reinforcements which is or are adjacent to it. The intertwining of the textile hooping wire reinforcing elements and the wire frame element(s) defines a weave. A well-known weave is linen weave also called plain weave.

[015] Textile monofilaments and fibers are usually classified into two main categories, natural monofilaments and fibers and chemical monofilaments and fibers. Natural monofilaments and fibers include monofilaments and fibers of vegetable origin (including in particular cotton), of animal origin and of mineral origin. Chemical monofilaments and fibers include man-made monofilaments and fibers and synthetic monofilaments and fibers. Monofilaments and artificial fibers are made from natural raw materials and include in particular viscose made from wood cellulose. Synthetic monofilaments and fibers include organic polymeric monofilaments and fibers (eg, polyesters and polyamides) as well as inorganic polymeric monofilaments and fibers (eg, glass and carbon).

[016] Thus, in accordance with the invention, the presence of natural monofilaments and natural fibers as well as the presence of artificial monofilaments and artificial fibers will be avoided as much as possible and preferably completely.

[017] Each hooping wire reinforcement element is textile insofar as it comprises, for at least 50% of its mass, one or more textile monofilaments and/or one or more textile fibers and preferably consists of one or more of several textile monofilaments and/or of one or more textile fibres.

[018] A monofilament is a unitary wire element of very long and continuous length, generally obtained by spinning a molten material. A fiber is a unitary wired element of short length. Several fibers are spun together to obtain a continuous thread. Thus, in the case where the assembly comprises polymeric synthetic fibers alone or in combination with polymeric synthetic monofilaments, the assembly comprises one or more continuous thread(s), each continuous thread being formed by a yarn (or assembly) of these polymeric synthetic fibers.

[019] In order to improve the compromise between the vibratory discomfort generated by the pockets of oxidation and the mass of the tire and therefore its rolling resistance, the invention proposes to take advantage of the wired element(s) of weft conductive little or not at all to corrosive agents to reduce the thickness of the material(s) separating the textile hooping wire reinforcement elements from the axially central part of the tread and the metal working wire reinforcement elements from the radially outermost working layer and therefore radially closest to the textile hooping wire reinforcement elements of the axially central part of the rolling. This thickness is represented by the mean radial distance E2. Thus, even if the risk of seeing the corrosive agents reach the radially outermost working layer is increased by reducing the average radial distance E2 separating it from the hooping reinforcement, the fact of preventing the conduction of the corrosive agents by the or the wire frame elements make it possible not to increase, or even to reduce, the total surface area of the oxidation pockets.

[020] Thus, in a first improved compromise compared to the state of the art, it is possible to choose to greatly reduce the average radial distance E2. The increase in the total surface of the oxidation pockets will then be prevented without necessarily reducing it, but the tire will be greatly lightened and its rolling resistance will therefore be reduced. In a second improved compromise compared to the state of the art, it is possible to choose to moderately reduce the average radial distance E2. The total surface of the oxidation pockets will then be reduced and the tire will be moderately lightened and its rolling resistance will be moderately reduced. The choice of compromise will be chosen by those skilled in the art according to the use for which the tire is intended.

[021] The determination of the average radial distance E2 is done on the axially central part of the crown by measuring, between the surfaces, several radial distances axially distributed over the width of the axially central part of the crown. For example, a distance will be measured every centimeter in the axial direction starting from an end plane axially delimiting the axially central part of the vertex. These measurements will be taken in several meridian section planes evenly distributed over the circumference of the tire, for example in four meridian section planes. The average of the radial distances thus measured will then be averaged in order to obtain the average radial distance E2.

[022] Radial distance between two surfaces means the straight distance between a point on one of the surfaces and its projection onto the other of the surfaces in the radial direction of the tire.

[023] The axially central part of the tread is the axial part of the tread of the axially central part of the crown. These axially central parts of the crown and of the tread are delimited axially by the same first and second end planes, each first and second end plane being perpendicular to the axial direction of the tire and passing through first and second points located axially at an axial distance from the median plane of the tire equal to 25% of the width of the running surface.

[024] Conventionally, the rolling surface is determined on a tire mounted on a measuring rim and inflated to the nominal pressure (250 kPa or 290 kPa depending on whether it is a standard or reinforced tyre) within the meaning of the ETRTO (European Tire and Rim Technical Organization) standard manual, 2020. In the case of a clear boundary between the running surface and the rest of the tire, the axial width of the running surface is simply measured. In the case where the running surface is continuous with the outer surfaces of the sidewalls of the tire, the axial limit of the running surface passes through the point for which the angle between the tangent to the running surface and a straight line parallel to the axial direction passing through this point is equal to 30°. When there are several points on a meridian section plane for which said angle is equal in absolute value to 30°, the radially outermost point is retained.

[025] Optionally and preferably, the tire according to the invention is for a vehicle selected from passenger vehicles, light commercial vehicles and motorhomes and even more preferably the tire according to the invention is for a passenger vehicle.

[026] A passenger vehicle tire is a passenger car or passenger car tire as defined within the meaning of the ETRTO standard manual, 2020. Such a tire has a section in a meridian section plane characterized by a section height H and a nominal section width SW within the meaning of the ETRTO standard manual, 2020. More preferably and optionally, the passenger vehicle tires to which the invention will advantageously be applied are such that the H/S ratio, expressed as a percentage , is at most equal to 90, preferably at most equal to 80 and more preferably at most equal to 70 and is at least equal to 20, preferably at least equal to 30, and the nominal section width SW is at least equal to 115 mm, preferably at least equal to 155 mm and more preferably at least equal to 175 mm and at most equal to 385 mm, preferably at most equal to 315 mm, more preferably at most equal to 285 mm. In addition, the hook diameter D, defining the diameter of the mounting rim of the tire, is at least equal to 12 inches, preferably at least equal to 16 inches and at most equal to 24 inches, preferably at most equal to 21 inches. The nominal section width SW, the nominal aspect ratio H/S and the hook diameter D are those of the dimension marking on the sidewall of the tire and in accordance with the ETRTO 2020 standard manual.

[027] A tire for a light commercial vehicle or motor home is as defined within the meaning of the manual of the ETRTO standard in sections 10 to 12 of the part relating to tires for commercial vehicles.

[028] The depth of a cutout is, on a new tire, the maximum radial distance between the bottom of the cutout and its projection on the ground when rolling the pneumatic. The maximum value of the depths of the cutouts is called the tread height. In most tires, the deepest cutout in the axially central part of the tread is also the deepest cutout in the tread and therefore defines the tread height.

[029] A cut designates either a groove or an incision and forms a space opening onto the running surface.

[030] An incision or a groove has, on the rolling surface, two main characteristic dimensions: a width and a curvilinear length such that the curvilinear length is at least equal to twice the width. An incision or a groove is therefore delimited by at least two main side faces determining its curvilinear length and connected by a bottom face, the two main side faces being distant from each other by a non-zero distance, called width of the cutout.

[031] The width of a cutout is, on a new tire, the maximum distance between the two main lateral faces measured, in the case where the cutout does not include a bevel, at a radial dimension coinciding with the rolling surface, and in the case where the cutout comprises a chamfer, at the most radially outer radial dimension of the cutout and radially inner to the chamfer. The width is measured substantially perpendicular to the main side faces.

[032] The axial width of a cutout is, for its part, measured along the axial direction of the tire, for example in a meridian section plane of the tire. [033] An incision is such that the distance between the main side faces is appropriate to allow at least partial contact between the main side faces delimiting said incision when passing through the contact area, in particular when the tire is at the in new condition and under normal driving conditions, including in particular the fact that the tire is at nominal load and at nominal pressure.

[034] A groove is such that the distance between the main side faces is such that these main side faces cannot come into contact with one another under normal driving conditions, including in particular the fact that the tire is at rated load and rated pressure.

[035] A cutout can be transverse or circumferential.

[036] A transverse cutout is such that the cutout extends along an average direction forming an angle strictly greater than 30°, preferably greater than or equal to 45° with the circumferential direction of the tire. The mean direction is the shortest curve joining the two ends of the cutout and parallel to the running surface. A transverse cutout can be continuous, i.e. not be interrupted by a carving block or other cutout so that the two main side faces determining its length are uninterrupted along the length of the transverse cutout. A transverse cutout may also be discontinuous, i.e. interrupted by one or more tread blocks and/or one or more cutouts so that the two main side faces determining its length are interrupted by one or more tread blocks and/or one or more cutouts.

[037] A circumferential cutout is such that the cutout extends along an average direction forming an angle less than or equal to 30°, preferably less than or equal to 10° with the circumferential direction of the tire. The mean direction is the shortest curve joining the two ends of the cutout and parallel to the running surface. In the case of a continuous circumferential cutout, the two ends coincide with each other and are joined by a curve making a complete turn of the tire. A circumferential cutout may be continuous, that is to say not be interrupted by a tread block or other cutout so that the two main lateral faces determining its length are uninterrupted over the whole of one revolution of the tire . A circumferential cutout may also be discontinuous, i.e. interrupted by one or more tread blocks and/or one or more cutouts such that the two main side faces determining its length are interrupted by one or more tread blocks and/or one or more cutouts over the whole of one revolution of the tire.

[038] In the case of a circumferential cutout located outside the median plane of the tire, the side faces are called the axially inner faces and the axially outer face, the axially inner face being arranged, at a given azimuth, axially inside the face axially exterior with respect to the median plane.

[039] Each circumferential cutout includes axially inner and outer axial ends. Whether in the case of a circumferential cutout without a chamfer or provided with a chamfer, each axially inner and outer end is located respectively on each axially inner or outer edge. [040] In the case of a transverse cutout, the lateral faces are called the leading face and the trailing face, the leading face being that whose edge, for a given circumferential line, enters the contact area before the edge of the trailing face.

[041] In embodiments, the or each circumferential cutout, whether main or not, is provided with chamfers. A chamfer of a circumferential cutout can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a planar face inclined relative to the axially inner and outer face it extends to the axially inner or outer edge axially delimiting the circumferential cutout. A rounded chamfer is formed by a curved face joining tangentially to the axially inner or outer face that it extends. A chamfer of a circumferential cutout is characterized by a height and a width equal respectively to the radial distance and to the axial distance between the common point between the axially inner or outer face extended by the chamfer and the axially inner or outer edge axially delimiting circumferential cutout. [042] In embodiments, the or each transverse cutout is provided with chamfers. In other words, each transverse cutout being delimited radially by leading and trailing faces circumferentially delimiting said transverse cutout and interconnected by a bottom face radially inwardly delimiting said transverse cutout. A chamfer of a crosscut can be a straight chamfer or a rounded chamfer. A straight chamfer is formed by a flat face inclined with respect to the leading or trailing face which it extends as far as the leading or trailing edge circumferentially delimiting the transverse cutout. A rounded chamfer is formed by a curved face connecting tangentially to the leading or trailing face which it extends. A chamfer of a transverse cutout is characterized by a height and a width equal respectively to the radial distance and to the distance in a direction perpendicular to the leading or trailing faces between the common point between the leading or trailing face extended by the chamfer and the leading or trailing edge circumferentially delimiting the transverse cutout.

[043] The tire according to the invention has a substantially toroidal shape around an axis of revolution substantially coinciding with the axis of rotation of the tire. This axis of revolution defines three directions conventionally used by those skilled in the art: an axial direction, a circumferential direction and a radial direction.

[044] By axial direction is meant the direction substantially parallel to the axis of revolution of the tire or of the mounted assembly, that is to say the axis of rotation of the tire or of the mounted assembly.

[045] Circumferential direction means the direction which is substantially perpendicular both to the axial direction and to a radius of the tire or of the mounted assembly (in other words, tangent to a circle whose center is on the axis of rotation of the tire or of the mounted assembly).

[046] The term radial direction means the direction along a radius of the tire or the mounted assembly, that is to say any direction intersecting the axis of rotation of the tire or the mounted assembly and substantially perpendicular to this axis.

[047] The median plane of the tire (denoted M) means the plane perpendicular to the axis of rotation of the tire which is located at the axial mid-distance of the two beads and passes through the axial center of the crown.

[048] By equatorial circumferential plane of the tire is meant, in a meridian section plane, the plane passing through the equator of the tire, perpendicular to the median plane and to the radial direction. The equator of the tire is, in a meridian section plane (plane perpendicular to the circumferential direction and parallel to the radial and axial directions) the axis parallel to the axis of rotation of the tire and located equidistant between the radially most outside of the tread intended to be in contact with the ground and the radially innermost point of the tire intended to be in contact with a support, for example a rim.

[049] Meridian plane means a plane parallel to and containing the axis of rotation of the tire or of the mounted assembly and perpendicular to the circumferential direction. [050] By radially inner, respectively radially outer, is meant closer to the axis of rotation of the tire, respectively further from the axis of rotation of the tire. By axially inside, respectively axially outside, is meant closer to the median plane of the tire, respectively further from the median plane of the tire.

[051] By bead, we mean the portion of the tire intended to allow the attachment of the tire to a mounting support, for example a wheel comprising a rim. Thus, each bead is in particular intended to be in contact with a hook of the rim allowing it to be attached.

[052] By carcass or working layer, we mean a layer comprising continuous wire reinforcement elements from one edge to the other of the carcass or working layer. Thus, a carcass or working layer can be turned over in the tire so as to form a double thickness of said carcass or working layer. Two different carcass or working layers include discontinuous wire reinforcement elements from one layer to the other. Two superposed carcass or working layers form a thickness equal to the sum of the thicknesses of the two carcass or working layers.

[053] Any interval of values denoted by the expression "between a and b" represents the range of values going from more than a to less than b (i.e. limits a and b excluded) while any interval of values designated by the expression “from a to b” means the range of values going from a to b (that is to say including the strict limits a and b).

[054] The characteristics of the textile hooping wire reinforcement elements as well as the weft wire element(s) can be determined by extracting these elements from the tire, for example according to a method in accordance with standard ASTM D885/D885M - 10a - paragraph 6.4.

[055] Unless explicitly stated to the contrary, the geometric characteristics of the tire are produced on an unloaded and uninflated tire or on a section of the tire in a meridian plane when possible.

[056] Optionally and preferentially, at least 50%, preferably at least 75% and even more preferentially 100% of the mass of the or each weft wire element is constituted by the textile monofilaments and/or textile fibers chosen ( e) from monofilaments and organic polymeric synthetic fibers, monofilaments and inorganic polymeric synthetic fibers and assemblies of these monofilaments and fibers. In other words, when 100% of the mass of the or each filamentary weft element is made up of textile monofilaments and/or textile fibers chosen from monofilaments and organic polymeric synthetic fibers, monofilaments and inorganic polymeric synthetic fibers and the assemblies of these monofilaments and fibres, the or each weft thread element consists of the textile monofilaments and/or textile fibers chosen from among the monofilaments and the organic polymeric synthetic fibers, the monofilaments and the inorganic polymeric synthetic fibers and assemblies of these monofilaments and fibers. In this case, the or each weft wire element is devoid of natural monofilament, natural fibers, artificial monofilament and artificial fibers.

[057] By maximizing the mass proportion of the monofilaments and/or of the non-conductive fibers of the corrosive agents in the or each weft wire element, the risk of conducting the corrosive agents is reduced.

[058] The proportion of the mass of the monofilaments and the fibers considered is determined by measuring the mass of the weft wire element then separating the monofilaments and the fibers considered and measuring their mass. The ratio of the two masses is equal to the proportion of mass sought.

[059] Optionally and advantageously, at least 50%, preferably at least 75% and even more preferably 100% of the cumulative length of the weft wire element(s) comprises several textile monofilaments and/or textile fibers chosen from monofilaments and organic polymeric synthetic fibers, monofilaments and inorganic polymeric synthetic textile fibers and assemblies of these monofilaments and fibers. By maximizing the length of weft wire elements that do not conduct corrosive agents, the risk of conducting corrosive agents is reduced.

[060] The proportion of cumulative length of the wire frame element(s) considered is determined on a representative portion of the tire and if necessary on the entire tire by measuring the cumulative length of the wireframe element(s) and by measuring the cumulative length of the wireframe element(s) s) frame considered. The ratio of the two cumulative lengths is equal to the proportion of cumulative length sought.

[061] In optional embodiments making it possible to maximize the lightening of the tire, E2 <0.30 mm, preferably E2 <0.20 mm.

[062] Optionally, in a first variant, E2>0.05 mm, preferably E2>0.10 mm. The presence of a thickness of non-zero material(s) makes it possible to avoid direct contact between the textile hooping wire reinforcement elements and the metal working wire reinforcement elements and therefore excessive propagation of corrosive agents from the shrink-fit reinforcement towards the working reinforcement. Such a non-zero thickness also makes it possible to ensure mechanical decoupling of the working reinforcement and the shrink-fit reinforcement.

[063] Optionally, in a second variant, E2<0.05 mm. Contrary to the first variant, it will be sought here to minimize the thickness of material(s), or even to eliminate it so as to bring the textile hooping wire reinforcement elements into direct contact with the working wire reinforcement elements. metallic. Even if a propagation of the corrosive agents could take place on the metal work wire reinforcement elements crossing the textile hooping wire reinforcement element(s) possibly leading these corrosive agents, the weft wire reinforcement element(s) of the invention will reduce or even suppress the spread of corrosive agents on the metal working wire reinforcement elements that do not cross the textile hooping wire reinforcement element(s) conducting the corrosive agents.

[064] Whether in the first or the second variant, at least one of the textile hooping wire reinforcement elements is, in certain possible but non-limiting embodiments, in contact with at least one of the wire reinforcement elements of metal workings of the radially outermost working layer. As explained previously, the bringing into contact of the textile hooping wire reinforcement elements and at least one of the metal working wire reinforcement elements only leads to a limited spread of corrosive agents in the working reinforcement thanks to the or to the weft wire reinforcement elements of the invention.

[065] Optionally and advantageously, the or at least one of the wireframe element(s) comprises several monofilaments and/or organic polymeric synthetic textile fibers. Such monofilaments and fibers are particularly inexpensive. [066] Optionally and preferentially, at least 50%, preferably at least 75% and even more preferentially 100% of the mass of the or each weft wire element is constituted by the textile monofilaments and/or textile fibers chosen ( e) from monofilaments and organic polymeric synthetic fibers. In other words, when 100% of the mass of the or each filamentary weft element consists of the textile monofilaments and/or textile fibers chosen from among the monofilaments and the organic polymeric synthetic fibers, the or each element weft yarn consists of textile monofilaments and/or textile fibers chosen from monofilaments and organic polymeric synthetic fibers. In this case, the or each weft wire element is devoid of natural monofilament, natural fibers, artificial monofilament and artificial fibers. The proportion of mass is determined as previously described.

[067] Optionally and advantageously, at least 50%, preferably at least 75% and even more preferably 100% of the cumulative length of the weft wire element(s) comprises several monofilaments and/or fibers organic polymeric synthetics. The proportion of cumulative length is determined as previously described.

[068] In an optional and advantageous embodiment, the monofilaments and the organic polymeric synthetic fibers are chosen from among the monofilaments and the polyester fibers, the monofilaments and the polyamide fibers, the monofilaments and the polyketone fibers , polyurethane monofilaments and fibers, acrylic monofilaments and fibers, polyolefin monofilaments and fibers, polyetheretherketone monofilaments and fibers and assemblies of these monofilaments and these fibers, preferably from monofilaments and the polyester fibers, the monofilaments and the polyamide fibers and the assemblies of these monofilaments and of these fibers and more preferably the monofilaments and the organic synthetic fibers are monofilaments and polyester fibers. Among the polyesters, PET (poly(ethylene terephthalate), PEN (poly(ethylene naphthalate) and PEF (polyethylene 2,5-furandicarboxylate) and more particularly PET will be chosen. Among the polyamides, will preferably choose aliphatic polyamides and aromatic polyamides, and more particularly aliphatic polyamides.

[069] In certain optional and preferred embodiments, in the axially central part of the crown, the average radial distance E1 between: - the surface passing through the radially innermost point of the or each deepest cutout of the axially central part of the tread and substantially parallel to the tread surface, and

- the radially outer surface passing through the radially outermost points of the most radially outer textile hooping wire reinforcement elements among the textile hooping wire reinforcement elements, is such that E1 < 2.00 mm, preferably E1 < 1 80 mm, more preferably E1 <1.50 mm, even more preferably E1 <1.40 mm and very preferably E1 <1.20 mm.

[070] In fact, so as to also improve the compromise between the vibratory discomfort generated by the pockets of oxidation and the mass of the tire, these embodiments propose to also take advantage of the wired element(s) of weft with little or no conductor(s) of corrosive agents to reduce not only the thickness of the material(s) separating the textile hooping wire reinforcement elements from the axially central part of the tread and the metal work wire reinforcement elements of the radially outermost working layer of the axially central part of the tread, but also to reduce the thickness of the material or materials separating the bottom of the deepest cutout of the axially central part of the tread and the textile hooping wire reinforcing elements of the axially central part of the tread. This thickness is represented by the mean radial distance E1. Thus, similarly to E2, even if the risk of seeing the corrosive agents reach the hooping reinforcement is increased by reducing the average radial distance E1, the fact of preventing the conduction of the corrosive agents by the wire element(s) of frame makes it possible not to increase, or even to reduce the total surface of the oxidation pockets.

[071] Analogously to what has been described for E2, in a first improved compromise compared to the state of the art, it is possible to choose to greatly reduce the average radial distance E1. The increase in the total surface of the oxidation pockets will then be prevented without necessarily reducing them, but the tire will be considerably lightened. In a second improved compromise compared to the state of the art, it is possible to choose to moderately reduce the average radial distance E1. The total surface of the oxidation pockets will then be reduced and the tire will be moderately lightened. The choice of compromise will be chosen by those skilled in the art according to the use for which the tire is intended.

[072] The determination of the average radial distance E1 is done on the axially central part of the vertex by measuring, between the surfaces, several radial distances axially distributed over the width of the axially central part of the vertex. For example, a distance will be measured every centimeter along the axial direction starting from an end plane axially delimiting the axially central part of the crown. Of course, if the radially outermost point of the radially outermost textile hooping wire reinforcing element among the textile hooping wire reinforcing elements is radially outside the surface passing through the radially innermost point of the or each deepest cut in the axially central part of the tread and substantially parallel to the tread surface, the measured radial distance is considered to be negative in order to take into account the greater probability of the effect of corrosive agents . Conversely, and in the vast majority of cases, if the radially outermost point of the most radially outer textile hooping wire reinforcement element among the textile hooping wire reinforcement elements is radially inside of the surface passing through the radially innermost point of the or each deepest cutout of the axially central part of the tread and substantially parallel to the tread surface, the measured radial distance is considered to be positive.

[073] These measurements will be taken in several meridian section planes evenly distributed over the circumference of the tire, for example in four meridian section planes. The average of the radial distances thus measured will then be averaged in order to obtain the average radial distance E1.

[074] Optionally and advantageously, E1>0.20 mm, preferably E1>0.50 mm and more preferably E1>1.00 mm. The presence of a non-zero thickness of material(s) makes it possible to protect the wired textile hooping reinforcement elements from too many attacks and too much penetration of corrosive agents into the crown reinforcement.

[075] In optional embodiments, in the axially central part of the crown, the average radial distance H between:

- the surface passing through the radially innermost point of the or each deepest cutout of the axially central part of the tread and substantially parallel to the tread surface, and

- the radially outer surface passing through the radially outermost points of the metallic working wire reinforcement elements of the radially outermost working layer of the working reinforcement, is such that H < 3.00 mm, preferably H <2.75 mm, more preferably H <2.50 mm and even more preferably H <2.35 mm.

[076] The relatively low value of E2 and optionally, the relatively low value of E1 make it possible, if desired, to reduce the average radial distance H and therefore to lighten the tire. In other embodiments, it will be possible, by reducing E2 and optionally, by reducing E1, to keep a relatively high value of H by increasing the tread height, in particular to increase the number of kilometers that the tire is capable of covering.

[077] In one embodiment, the hooping reinforcement is delimited axially by two axial edges of the hooping reinforcement and comprises a strip wound helically over several circumferential turns so as to extend axially between the axial edges of the hooping reinforcement.

[078] In a first variant of this embodiment, the strip is wound helically over several circumferential turns so that, in the axially central part of the crown, two adjacent circumferential turns of the strip do not overlap axially and radially with each other. Thus, the strip having two longitudinal axial edges, in the axially central part of the crown, the adjacent longitudinal axial edges of the two adjacent circumferential turns are axially contiguous without forming an axial and radial overlap or are axially distant from each other without form an axial and radial overlap between the two circumferential towers. This avoids forming a double thickness in the hooping reinforcement. In the case where the adjacent longitudinal axial edges of the two adjacent circumferential towers are spaced apart from each other without forming an axial and radial overlap between the two circumferential towers, the compromise between high-speed endurance and the mass of the tire by shrinking more the parts most sensitive to high speed which are in particular the parts axially external to the axially central part and by shrinking less the parts less sensitive to high speed which is in particular the axially central part.

[079] In a second variant of this embodiment, in the axially central part of the crown, two adjacent circumferential turns form an axial and radial overlap between them. In this second variant, one generally speaks of tiling because of the covering of the turns of the strips with each other in the manner of roofing tiles.

[080] In order to make the tire manufacturing process as productive as possible, the strip comprises several textile hooping wire reinforcing elements substantially parallel to each other and embedded in a polymer matrix, preferably an elastomeric matrix.

[081] Advantageously, each textile hooping wire reinforcement element extends along a main hooping direction forming, with the circumferential direction of the tire, an angle, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°.

[082] In an advantageous embodiment, the textile hooping wire reinforcement elements are connected to each other by several weft wire elements substantially parallel to each other in a main weft direction that is non-collinear with the main weft direction. hooping, the weft wire elements being discontinuous with each other.

[083] Optionally, the main weft direction forms an angle greater than or equal to 45°, preferably greater than or equal to 75° with the main hooping direction. [084] In order to manufacture the hooping reinforcement and the strip of the embodiments described above, a strip is manufactured which, once wound helically around the working reinforcement, forms the hooping reinforcement. During a step in the manufacture of a very wide fabric, the textile hooping wire reinforcement elements are arranged substantially parallel to each other. Then, the textile hooping wire reinforcement elements are separated into a first and a second ply of textile hooping wire reinforcement elements.

[085] Then, the textile hooping wire reinforcement elements are connected together by one or more weft wire elements, each weft wire element extending over the entire width of the wide fabric. To do this, the weft wire elements are interlaced alternately with the textile hooping wire reinforcement elements of the first ply of warp wire elements and of the second ply of warp wire elements.

[086] During a subsequent sizing step, the textile hooping wire reinforcement elements and the weft wire elements are coated with one or more layers of one or more adhesive compositions, then the large-width fabric previously obtained so as to obtain a large-width glued fabric.

[087] Then, during a subsequent calendering step, the bonded wide-width fabric is embedded in an elastomeric matrix so as to obtain a wide-width calendered fabric.

[088] Then, during a cutting step, the large-width calendered fabric is cut so as to obtain several small-width strips in which the textile hooping wire reinforcing elements extend in a direction substantially parallel to the direction of the longest length of the strip.

[089] It will be noted that during the step in which the textile hooping wire reinforcement elements are connected together by one or more weft wire elements, it is possible, in certain embodiments, to use a loom without a shuttle, for example a projectile loom, a flexible or rigid lance loom or a projection loom. In the case of a projection loom, an air-jet loom will very advantageously be used in combination with tousled weft wire elements. By ruffled weft wire element is meant a wire element comprising monofilaments, fibers or threads coming out of the circle circumscribed to a theoretical wire element corresponding to the weft wire element from which the monofilaments, fibers or threads have been removed outside the circumscribed circle. By ruffled weft wire element, it is meant that the weft wire element is neither smooth nor textured as described in application WO2015016791.

[090] In other embodiments, a shuttle loom may be used that does not specifically require tousled weft wire elements.

[091] In embodiments, each textile hooping wire reinforcement element comprises one or more organic synthetic monofilament(s), preferably an assembly comprising several organic synthetic monofilaments. Thus, the wired textile hooping elements are non-conductive of corrosive agents and the propagation of these corrosive agents is avoided as far as possible along the wired textile hooping elements arranged close to or in contact with the attacks.

[092] Optionally, the organic polymeric synthetic monofilaments are chosen from polyester monofilaments, aliphatic polyamide monofilaments, aromatic polyamide monofilaments, polyketone monofilaments and assemblies of these monofilaments, preferably from polyester monofilaments , aliphatic polyamide monofilaments, aromatic polyamide monofilaments and assemblies of these monofilaments and even more preferably among polyester monofilaments, aliphatic polyamide monofilaments and assemblies of aliphatic polyamide monofilaments and aromatic polyamide monofilaments. Among the polyesters, PET (poly(ethylene terephthalate), PEN (poly(ethylene naphthalate) and PEF (polyethylene 2,5-furandicarboxylate) and more particularly PET will be chosen. Among the aliphatic polyamides, aliphatic polyamides 6 or 6.6 will preferably be chosen Among the aromatic polyamides, poly(metaphenylene isophthalamides) and poly(paraphenylene terephthalamide) will be preferably chosen.

[093] In advantageous embodiments, the or each working layer is delimited axially by two axial edges of the or each working layer and comprises metallic working wire reinforcement elements extending axially from one axial edge to the other axial edge of the or each working layer substantially parallel to each other.

[094] Optionally and whatever the configuration of the working reinforcement, each metallic work wire reinforcement element extends along a main direction forming, with the circumferential direction of the tire, an angle, in absolute value, strictly greater than 10°, preferably ranging from 15° to 50° and more preferably ranging from 20° to 35°.

[095] In a first configuration of the working reinforcement, the working reinforcement comprises a radially inner working layer and a radially outer working layer arranged radially outside the radially inner working layer. In this variant, the main direction in which each working wire reinforcement element of the radially innermost working layer extends and the main direction in which each working wire reinforcement element of the radially innermost working layer extends the outermost form, with the circumferential direction of the tire, angles of opposite orientations. The angles may have identical or different absolute values.

[096] In a second configuration of the working reinforcement, the working reinforcement comprises a single working layer. In this second configuration, the radially outermost working layer is therefore the only working layer. The presence of a single working layer makes it possible in particular to lighten the tire, therefore to reduce the energy dissipated by hysteresis of the crown and therefore to reduce the rolling resistance of the tire. Thus, the working reinforcement is, with the exception of the working layer, devoid of any layer reinforced by wire reinforcing elements. The wire reinforcement elements of such reinforced layers excluded from the working reinforcement of the tire include metal wire reinforcement elements and textile wire reinforcement elements. Very preferably, the working reinforcement consists of the single working layer.

[097] In one embodiment making it possible to reduce the mass of the metallic working wire reinforcement elements, each metallic working wire reinforcement element of the or each working layer consists of a metallic monofilament.

[098] Optionally, the tire comprising two beads, two sidewalls each connecting each bead to the crown and a carcass reinforcement anchored in each bead, the carcass reinforcement extends radially in each sidewall and axially in the crown radially internally to the top frame.

[099] In a first configuration of the carcass reinforcement, the carcass reinforcement comprises a single carcass layer. In this first configuration, the carcass reinforcement is, with the exception of the single carcass layer, devoid of any layer reinforced by wire reinforcement elements. The wire reinforcing elements of such reinforced layers excluded from the tire carcass reinforcement include metallic wire reinforcement elements and textile wire reinforcement elements. Very preferably, the carcass reinforcement consists of the single carcass layer

In a second configuration of the carcass reinforcement, the carcass reinforcement comprises two layers of carcass. In this second configuration, the main directions of the carcass wire reinforcement elements of the two carcass layers are preferably substantially parallel to each other.

[0101] Advantageously, the carcass reinforcement comprising at least one carcass layer, the or each carcass layer is delimited axially by two axial edges of the or each carcass layer and comprises carcass textile cord reinforcement elements extending axially from one axial edge to the other axial edge of the or each carcass layer.

[0102] In a first variant of the carcass reinforcement usable in combination with the first and the second configuration of the carcass reinforcement as well as with the first and the second configuration of the working reinforcement, each reinforcing element carcass cord extends along a main direction of each carcass cord reinforcement element forming, with the circumferential direction of the tire, a substantially constant angle between each axial edge of the or each carcass layer and, in absolute value, greater than or equal to 60°, preferably ranging from 80° to 90°.

[0103] In a second variant of the carcass reinforcement that can be used in combination with the first and the second configuration of the carcass reinforcement, the working reinforcement comprising a single working layer, each carcass wire reinforcement element extends in a main direction of each carcass wire reinforcement element forming, with the circumferential direction of the tire:

- an angle, in absolute value, strictly less than 80° in an axially central portion of the carcass layer extending axially radially plumb with the working layer,

- an angle, in absolute value, ranging from 80° to 90° in two axially lateral portions of the carcass layer extending radially axially between the axially central portion and each axial edge of the carcass layer.

The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which: FIG. 1 is a view, in a sectional plane meridian, of a tire according to a first embodiment of the invention, Figure 2 is a schematic cut-away view of the tire of Figure 1 illustrating the arrangement of the wire reinforcing elements in the crown, Figure 3 is a top view of the tread of the tire of Figure 1, Figure 4 is a detail view of the axially central part of the crown of the tire of FIG. 1, FIG. 5 is a view of the hooping reinforcement of the tire of FIG. 1, FIG. 6 is a photograph of a wire element of weft and several textile hooping wire reinforcing elements of the hooping reinforcement of FIG. 5, FIG. 7 and FIG. 8 are views similar to those of FIG. 1 and FIG. 4 of a tire according to a second embodiment, Figure 9 is a view similar to that of Figure 4 of a tire according to a third embodiment, Figure 10 is a view similar to that of Figure 5 of the tire according to the third embodiment realization, figure 11 and fig re 12 are views similar to those of Figure 9 and Figure 10 of a tire according to a fourth embodiment.

[0105] In the figures, an X, Y, Z mark has been shown corresponding to the usual axial (Y), radial (Z) and circumferential (X) directions respectively of a tire.

There is shown in Figures 1 to 6 a tire according to the invention and designated by the general reference 10. The tire 10 has a substantially toroidal shape around an axis of revolution substantially parallel to the axial direction Y The tire 10 is intended for a passenger vehicle and has dimensions 225/45 R17. In the various figures, the tire 10 is shown in new condition, that is to say not having been driven yet.

The tire 10 comprises a crown 12 comprising a tread 14 carrying a tread surface 15 intended to come into contact with the ground when the tire 10 is rolling. The tread surface 15 is delimited axially by first and second axial ends 151, 152 passing through each point N arranged on either side of the median plane M and for which the angle between the tangent T to the running surface 15 and a straight line R parallel to the axial direction Y passing through this point is equal to 30°. The rolling surface 15 has an axial width L measured as the axial distance from the first axial end 151 to the second axial end 152. The crown 12 comprises an axially central part PO as well as two parts axially lateral P1 and P2 arranged axially on either side of the axially central part PO with respect to the median plane M.

The axially central portion PO extends axially over an axial width LO equal to 50% of the axial width L of the rolling surface 15. Each first and second axially lateral portion P1, P2 has an axial width L1, L2 equal to 25% of the axial width L of the rolling surface 15. The axially central portion PO is axially centered on the median plane M.

[0109] Referring to Figure 1, Figure 3 and Figure 4, the tread 14 comprises cutouts comprising main circumferential cutouts 72, 74, 76, 78, secondary circumferential cutouts 80, 82, 84 as well as transverse cutouts 90, 92, 94, 96, 98. The main circumferential cutouts 72, 74, 76, 78 are circumferential grooves.

Referring to Figure 4, each main circumferential cutout 72, 74, 76, 78 comprises two side faces Fr1, Fr2 and a bottom face Frd. Each main circumferential cutout 72, 74, 76, 78 has a depth He ranging from 4.00 mm to the tread height Hs, preferably ranging from 5.00 mm to the tread height Hs and more preferably ranging from 5.50 mm at tread height Hs. Each depth is greater than or equal to 50% of the tread height Hs. Here, Hs=6.50 mm and here each main circumferential cutout 74, 76 has an equal depth He=Hs=6.50 mm and each main circumferential cutout 72, 78 has a depth equal to 6.00 mm. Thus, each main circumferential cutout 74, 76 is the deepest cutout of the tire 10 and in particular of the axially central part PO.

The crown 12 also comprises a crown reinforcement 16 extending in the crown 12 along the circumferential direction X. The tire 10 also comprises a sealing layer 18 to an inflation gas being intended to delimit a closed internal cavity with a tire mounting support 10 once the tire 10 is mounted on the mounting support, for example a rim.

The crown reinforcement 16 comprises a working reinforcement 20 and a hooping reinforcement 22.

The working reinforcement 20 comprises two working layers 24, 26. The radially outer working layer 26 is arranged radially outside the radially inner working layer 24. The radially outer working layer 26 is therefore the radially outermost working layer of the working reinforcement 20.

The hooping reinforcement 22 comprises at least one hooping layer and here comprises a hooping layer 28. The crown reinforcement 16 is surmounted radially by the tread 14. Here, the hooping reinforcement 22, here the hooping layer 28, is arranged radially outside the working reinforcement 20 and radially inside the tread 14. The hooping reinforcement 22 is therefore radially interposed between the working reinforcement 20 and the tread 14.

The tire 10 comprises two sidewalls 30 extending the crown 12 radially inwards. The tire 10 further comprises two beads 32 radially inside the sidewalls 30. Each sidewall 30 connects each bead 32 to the crown 12.

The tire 10 comprises a carcass reinforcement 34 anchored in each bead 32, in this case is wrapped around two bead wires 33. The carcass reinforcement 34 extends radially in each sidewall 30 and axially in the crown 12 radially internally to the crown reinforcement 16. The crown reinforcement 16 is arranged radially between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 comprises at least one carcass layer and here comprises a single carcass layer 36. In this case, the carcass reinforcement 34 consists of the single carcass layer 36.

Referring to Figure 4, each working layer 24, 26, hooping 28 and carcass 36 comprises a polymer matrix, here an elastomeric matrix in which are embedded one or more wire reinforcement elements of the corresponding layer. The interfaces between two adjacent layers different layers are represented by dotted lines. These layers will now be described with reference to FIGS. 2 to 5.

The hooping reinforcement 22, here the hooping layer 28, is delimited axially by two axial edges 221, 222 of the hooping reinforcement 22. The hooping reinforcement 22 comprises a strip 40 wound helically over several circumferential turns Ci so as to extend axially between the axial edges 221, 222 of the hooping reinforcement 22. Several turns C1 to C4 have been shown in FIG. 5 arranged in the axially central part PO of the crown 12 The strip 40 comprises several textile hooping wire reinforcement elements 220 substantially parallel to each other and embedded in the elastomeric matrix of the hooping layer 28 described above so that the textile hooping wire reinforcement elements 220 are wound in a helix radially around the working reinforcement 20. The strip 40 is wound in a helix over several circumferential turns Ci so that, in the axially central part PO of the top 12, two turns s adjacent circumferential Ci of the strip 40 do not overlap axially and radially with each other. Thus, as can be seen in Fig. 5, in the axially central part PO of the crown 12, there is no radial superposition between one of the textile hooping reinforcing wire elements of a circumferential turn Ci of the strip 40 and one of the hooping reinforcing wire elements textiles of a circumferential turn Cj adjacent to the circumferential turn Ci.

[0121] Each wired textile hooping reinforcing element 220 extends along a main hooping direction DO forming, with the circumferential direction X of the tire 10, an angle AF, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°. Here, AF=-5°. The strip 40 comprises a density of 120 textile hooping wire reinforcing elements per decimeter of strip 40, this density being measured perpendicular to the direction D0.

[0122] Within the strip 40, the textile hooping wire reinforcement elements 220 are connected to each other by several weft wire elements 42 substantially parallel to each other in a main weft direction DT non-collinear with the main shrinking direction D0. The weft wire elements 42 are discontinuous with each other. The main weft direction DT forms an angle AT greater than or equal to 45°, preferably greater than or equal to 75° with the main hooping direction D0 and here substantially equal to 90°.

[0123] The radially inner working layer 24 is delimited axially by two axial edges 241, 242. The radially inner working layer 24 comprises metallic working wire reinforcement elements 240 extending axially from the axial edge 241 to the other axial edge 242 substantially parallel to each other in a main direction D1. Similarly, the radially outer working layer 26 is delimited axially by two axial edges 261, 262. The radially outer working layer 26 comprises metallic working wire reinforcement elements 260 extending axially from the axial edge 261 to the another axial edge 262 substantially parallel to each other in a main direction D2. The main direction D1 along which each wired working reinforcement element 240 of the radially inner working layer 24 extends and the main direction D2 along which each wired working reinforcement element 260 of the radially outer working layer extends 26 form, with the circumferential direction X of the tire 10, angles AT1 and AT2 respectively of opposite orientations. Each main direction D1, D2 forms, with the circumferential direction X of the tire 10, an angle AT1, AT2 respectively, in absolute value, strictly greater than 10°, preferably ranging from 15° to 50° and more preferably ranging from 20° at 35°. Here, AT1=-26° and AT2=+26°.

[0124] The carcass layer 36 is delimited axially by two axial edges 361, 362. The carcass layer 36 comprises carcass wire reinforcement elements 360 extending axially from the axial edge 361 to the other axial edge 362 of the carcass layer 36 along a main direction D3 forming with the circumferential direction X of the tire 10, a substantially constant angle AC between each axial edge 361, 362, in absolute value, greater than or equal to 60°, preferably ranging from 80° to 90° and here AC=+90°.

There is shown in Figure 6 a sectional view of the hooping armature 22 in a section plane perpendicular to the direction D0 and comprising one of the weft wire elements 42. With reference to Figure 6, each element hooping wire reinforcement 220 comprises one or more organic synthetic monofilament(s), preferably comprises an assembly comprising several organic synthetic monofilaments. The organic polymeric synthetic monofilaments are chosen from polyester monofilaments, aliphatic polyamide monofilaments, aromatic polyamide monofilaments, polyketone monofilaments and assemblies of these monofilaments, preferably from polyester monofilaments, aliphatic polyamide monofilaments, aromatic polyamide monofilaments and assemblies of these monofilaments and even more preferably among polyester monofilaments, aliphatic polyamide monofilaments and assemblies of aliphatic polyamide monofilaments and aromatic polyamide monofilaments. In this case, each hooping wire reinforcement element 220 conventionally comprises two multifilament strands, each multifilament strand being made up of a yarn of aliphatic polyamide monofilaments, here of nylon with a count equal to 94 tex, these two multifilament strands being individually twisted at 320 rpm in one direction and then twisted together at 320 rpm in the opposite direction. These two multifilament strands are wound in a helix around each other. As a variant, it is possible to use a hooping wire reinforcement element 220 comprising a multifilament strand made up of a yarn of monofilaments of aliphatic polyamide, here of nylon with a title equal to 140 tex and a multifilament strand made up of a yarn of monofilaments of aromatic polyamide, here of aramid with a titer equal to 167 tex, these two multifilament strands being twisted individually at 290 turns per meter in one direction then twisted together at 290 turns per meter in the opposite direction. These two multifilament strands are wound in a helix around each other. In this variant, we will have AT1=-29° and AT2=+29°.

Still, with reference to FIG. 6, each weft wire element 42 comprises several textile monofilaments and/or several textile fibers chosen from monofilaments and organic polymeric synthetic fibers, monofilaments and polymeric synthetic fibers inorganic materials and assemblies of these monofilaments and fibers. More precisely, at least 50%, preferably at least 75% and here 100% of the mass of each weft wire element 42 is constituted by the textile monofilaments and/or textile fibers chosen from monofilaments and fibers organic polymeric synthetics, monofilaments and inorganic polymeric synthetic fibers and assemblies of these monofilaments and fibers. In addition, at least 50%, preferably at least 75% and here 100% of the cumulative length of the weft wire elements 42 comprises several textile monofilaments and/or textile fibers chosen from monofilaments and polymeric synthetic fibers monofilaments and inorganic polymeric synthetic textile fibers and assemblies of these monofilaments and fibers.

At least one of the weft wire elements 42 comprises several monofilaments and/or organic polymeric synthetic textile fibers. More precisely, at least 50%, preferably at least 75% and here 100% of the mass of each weft wire element 42 is constituted by the textile monofilaments and/or textile fibers chosen from monofilaments and fibers organic polymeric synthetics. Furthermore, at least 50%, preferably at least 75% and here 100% of the cumulative length of the weft thread elements 42 comprises several monofilaments and/or organic polymeric synthetic fibers.

The organic polymer monofilaments and synthetic fibers are chosen from polyester monofilaments and fibers, polyamide monofilaments and fibers, polyketone monofilaments and fibers, polyurethane monofilaments and fibers, acrylic monofilaments and fibres, polyolefin monofilaments and fibres, polyetheretherketone monofilaments and fibers and assemblies of these monofilaments and these fibres, preferably among polyester monofilaments and fibres, monofilaments and polyamide fibers and the assemblies of these monofilaments and these fibers and here, the monofilaments and the organic synthetic fibers are monofilaments and polyester fibers.

In this case, each weft wire element 42 comprises, here consists of, two strands each comprising a core and a layer covering the core, the core comprising several polyester monofilaments and the layer comprising several fibers of polyester. The sum of the titles of the strands of each wire frame element 42 is equal to 22 tex. The title of each strand of weft wire element 42 ranges from 1 to 20 tex and preferably from 10 to 15 tex. Here it is 11 tex. In order to manufacture each weft wire element 42, the two strands are helically wound around each other at a twist of 1100 turns per meter, then each weft wire element 42 has a twist equal to 1100 turns per meter . The moisture pick-up rate of each weft wire element 42 is equal to 1.8%.

[0130] The density of the weft wire elements 42 ranges from 3.0 to 8.0 weft wire elements per dm of length of the strip 40, preferably from 3.0 to 6.0 weft wire elements per dm of length of the strip 40 and more preferably from 3.0 to 5.5 weft wire elements per dm of length of the strip 40. Here, the density of the weft wire elements 42 is equal to 5.0 weft wire elements per dm strip length 40.

Each metallic work wire reinforcement element 240, 260 comprises an assembly of two steel monofilaments wound helically at a pitch of 14 mm, each steel monofilament having a diameter equal to 0.30 mm. In FIG. 4, for reasons of clarity, the circle circumscribed to this assembly has been shown, the diameter of which is equal to the diameter of each metallic work wire reinforcement element 240, 260. In a variant, each wire reinforcement element metal working 240, 260 consists of a steel monofilament having a diameter equal to 0.30 mm. More generally, steel monofilaments have diameters ranging from 0.25 mm to 0.32 mm. In yet another variant, it is possible to use an assembly of six steel monofilaments having a diameter equal to 0.23 mm and comprising an internal layer of two monofilaments wound together in a helix at a pitch of 12.5 mm in a first direction, by for example the Z direction, and an outer layer of four monofilaments wound together in a helix around the inner layer at a pitch of 12.5 mm in a second direction opposite to the first direction, for example the S direction.

Each carcass wire reinforcement element 360 conventionally comprises two multifilament strands, each multifilament strand consisting of a yarn of polyester monofilaments, here of PET, these two multifilament strands being twisted individually at 240 turns per meter in one direction then helixed together at 240 rpm in the opposite direction. Each of these multifilament strands has a titer equal to 220 tex. In other variants, it is possible to use titles equal to 144 tex and twists equal to 420 turns per meter or titles equal to 334 tex and twists equal to 270 turns per meter.

In Figure 4, there is shown:

- the surface 100 passing through the radially innermost point of each deepest cutout 74, 76 of the axially central part PO of the tread 14 and substantially parallel to the tread surface 15, and

- the radially outer surface 102 passing through the radially outermost points of the most radially outer textile hooping wire reinforcement elements 220 among the textile hooping wire reinforcement elements 220, - the radially inner surface 104 passing through the radially innermost points of the most radially inner textile hooping wire reinforcement elements 220 among the textile hooping wire reinforcement elements 220,

- the radially outer surface 106 passing through the radially outermost points of the metallic working wire reinforcement elements 260 of the radially outermost working layer 26 of the working reinforcement 20.

In the axially central part PO of the crown 12, the mean radial distance E1 between the surface 100 and the radially outer surface 102 is such that E1<2.00 mm. Here, E1 <1.80 mm, preferably E1 <1.50 mm. Furthermore, E1>0.20 mm, preferably E1>0.50 mm and more preferably E1>1.00 mm. In this case E1 =1.50 mm.

In the axially central part PO of the crown 12, the mean radial distance E2 between the radially inner surface 104 and the radially outer surface 106 is such that E2<0.40 mm and preferably E2<0.30 mm. Further, E2 > 0.05 mm, preferably E2 > 0.10 mm. In this case, E2=0.23 mm.

In the axially central part PO of the crown 12, the average radial distance H between the surface 100 and the radially outer surface 106 is such that H <3.00 mm, preferably H <2.75 mm, more preferably H <2.50 mm and even more preferably H<2.35 mm. In this case, H=2.34 mm.

A tire according to a second embodiment will now be described with reference to FIG. 7 and FIG. 8. Elements similar to those of the first embodiment are designated by identical references.

Unlike the tire according to the first embodiment, the working reinforcement 20 of the tire 10 according to the second embodiment comprises a single working layer 26, which is therefore the radially outermost working layer of the working reinforcement 20.

In addition, each carcass wire reinforcement element 360 extends along a main direction D3 of each carcass wire reinforcement element 360 forming, with the circumferential direction X of the tire 10:

- an angle, in absolute value, strictly less than 80° in an axially central portion of the carcass layer extending axially radially plumb with the working layer 26,

- an angle, in absolute value, ranging from 80° to 90° in two axially lateral portions of the carcass layer 36 extending radially axially between the axially central portion and each axial edge of the carcass layer 36.

[0140] Tires comprising a single working layer as well as a carcass as described above as well as their manufacturing methods are known in particular from EP3489035, FR2797213 and FR1413102.

A tire according to a third embodiment will now be described with reference to FIG. 9 and FIG. 10. Elements similar to those of the preceding embodiments are designated by identical references.

Unlike the first embodiment, two adjacent circumferential turns Ci of strip 40 form a radial and axial overlap between them.

[0143] In Figure 9, there is shown the textile hooping wire reinforcement elements in the shape of a white circle when they belong to a given circumferential turn Ci and in the shape of a circle filled with small dots when they belong to the turn circumferential Ci+1 adjacent to circumferential tower Ci.

In this embodiment, the radially outer surface 102 is, in accordance with the invention, the surface passing through the radially outermost points of the most radially outer textile hooping wire reinforcing elements 220 among the reinforcing elements. textile hooping wire reinforcement elements 220. Here the textile hooping wire reinforcement elements 220 the most radially outer among the textile hooping wire reinforcement elements 220 are the textile hooping wire reinforcement elements 220 of each circumferential turn radially covering the reinforcement elements textile hooping cords 220 of the adjacent circumferential lap.

In addition, in this embodiment, the radially inner surface 104 is, in accordance with the invention, the surface passing through the radially innermost points of the radially innermost textile hooping wire reinforcing elements 220 among the textile hooping wire reinforcement elements 220. Here the textile hooping wire reinforcement elements 220 the most radially interior among the textile hooping wire reinforcement elements 220 are, on the one hand, the textile hooping wire reinforcement elements 220 of each circumferential turn being covered radially by the wired textile hooping reinforcing elements 220 of the adjacent circumferential turn and, on the other hand, the wired textile hooping reinforcing elements 220 of each circumferential turn not covered by other wired reinforcing elements of textile hooping 220.

A tire according to a fourth embodiment will now be described with reference to FIG. 11 and FIG. 12. Elements similar to those of the preceding embodiments are designated by identical references.

Analogously to the first and second embodiments, the tire 10 according to the fourth embodiment is such that the strip 40 is wound helically over several circumferential turns Ci so that, in the axially central PO of the crown 12, two adjacent circumferential turns Ci of the strip 40 do not overlap axially and radially with each other. Thus, as can be seen in FIG. 11 and FIG. 12, there is no radial superposition in the axially central part PO of the crown 12 between one of the textile hooping reinforcing wire elements of a circumferential turn Ci of the strip 40 and one of the textile hooping reinforcing wire elements of a circumferential lap Cj adjacent to the circumferential lap Ci.

[0148] Unlike the first and second embodiments, in the axially central part of the crown, the adjacent longitudinal axial edges of the two adjacent circumferential turns are axially spaced from each other without forming an axial and radial overlap between the two circumferential towers.

[0149] COMPARATIVE TESTS [0150] First comparative test

Two identical control tires T0 and T1 were compared with each other with the exception of their hooping reinforcement as well as the radial distance E2 during an aggressive rolling test described below.

The control tire T0 comprises a hooping reinforcement in which the textile weft wire reinforcement elements are not connected to each other by any weft wire element. In other words, the hooping reinforcement of the control tire T0 has no weft wire element. Further, E2=0.11mm.

The control tire T1 comprises a hooping reinforcement in which the textile weft wire reinforcement elements are connected to each other by the weft wire elements comprising cotton fibers. Also, E2=0.30mm.

Each tire tested was inflated to a pressure equal to 80% of its nominal inflation pressure on a passenger vehicle on which it is intended and capable of being fitted. This vehicle was driven on a circuit comprising a portion of paved road and a portion of road surfaced with crushed pebbles so as to present projecting edges and ends making it possible to attack the tread of the tire tested. The vehicle performs several laps of this circuit so as to allow the tread to be attacked by the crushed pebbles whether it is when passing over the portion of road surfaced with crushed pebbles or when passing over the portion of tarred road in in case crushed stones get stuck in the tread. The circuit also includes a wet portion comprising a saline water tank allowing the entry of corrosive agents in the aggressions caused by the stones. After a ride sufficient, for example several thousand kilometres, the tread and the hooping reinforcement are removed from each tire tested and the radially outermost working layer of the working reinforcement is analyzed.

During this analysis, the number Np of attacks present on the radially outermost working layer of the working reinforcement is first counted. In addition, for each oxidation pocket, the surface area of each oxidation pocket is measured. Then, we deduce the total surface St of all the oxidation pockets of the radially outermost working layer of the working reinforcement.

The various characteristics of the control tires T0, T1 as well as the results of the aggressive running test described above have been brought together in table 1 below.

The number of attacks Np is given in base 100 with respect to the control tire T1. A number Np greater than 100 means that the radially outermost working layer of the tire tested presents more damage than the control tire T1.

Similarly, the total area St is given in base 100 with respect to the control tire T1. A total surface area St greater than 100 means that the radially outermost working layer of the tire tested has a total surface area of oxidation pockets greater than that of the control tire T1.

Table 1

This first comparative test shows that the presence of threaded cotton weft elements in the control tire T1 generates a significant increase in the total surface St of oxidation pockets compared to the control tire T0 in which no threaded element of frame is present in the hooping reinforcement.

It will be noted that this is all the more unexpected since, on the one hand, the number of attacks Np is much higher in the control tire T0 than in the control tire T1 and that, on the other hand, the distance mean radial E2 is significantly lower in the control tire T0 compared to the tire witness T1. Indeed, with a higher number of attacks Np, one would have expected a higher number of oxidation pockets and therefore a higher total surface area St of oxidation pockets in the control tire T0 than in the tire witness T1. In addition, with a lower average radial distance E2 and therefore a lower thickness of material(s), one would have expected an easier propagation of corrosive agents and therefore a higher total area St of oxidation pockets in control tire T0 than in control tire T1.

[0161] Second comparative test

[0162] Control tires T2, T3 and a tire 10 according to the first embodiment described above were compared.

[0163] The control tire T3 comprises corded hooping reinforcement elements identical to those of the tire 10 according to the first embodiment. In the control tire T2, each wired hooping reinforcing element comprises two multifilamentary strands, each multifilamentary strand being made up of a yarn of monofilaments of aliphatic polyamide, here of nylon with a denier equal to 140 tex, these two multifilamentary strands being individually twisted at 250 rpm in one direction and then twisted together at 250 rpm in the opposite direction.

[0164] Furthermore, in the control tire T3 and the tire 10 according to the first embodiment, E1=1.50 mm. In the control tire T2, E1=2.30 mm.

In addition, we have E2=0.44 mm in the control tire T2, E2=0.38 mm in the control tire T3 whereas E2=0.23 mm in the tire 10 according to the first embodiment.

In addition, the weft wire elements comprise cotton fibers for the control tires T2 and T3, whereas the weft wire elements of the tire 10 according to the first embodiment are as described above.

The control tires T2, T3 and 10 according to the first embodiment were compared in the aggressive running test described above. The masses of the tires and their rolling resistance were also measured in accordance with appendix 6 of regulation 117 of the United Nations Economic Commission for Europe.

The different characteristics of the control tires T2, T3 and 10 according to the first embodiment as well as the results of the aggressive rolling test and of the mass and rolling resistance measurements have been collated in Table 2 below.

By comparing the control tires T2 and T3, it can be seen that the mean radial distance E1 and the mean radial distance E2 have been significantly reduced so as to lighten the control tire T3 relative to the control tire T2. Thus, the thickness of the material(s) protecting the wired reinforcing elements for textile hooping from attacks and the thickness of the material(s) protecting the wired reinforcing elements of metal work from attacks has been significantly reduced. corrosive agents propagated by the weft wire elements. A significant increase in the number of attacks Np is thus observed and, consequently, an increase in the total surface St of the oxidation pockets in the control tire T3 due to the significant propagation of corrosive agents via the wire elements of cotton weft as demonstrated in the first aggressive ride test. It should also be noted that this is all the more remarkable in that the wire-based hooping reinforcing elements of the control tire T2 being larger than those of the tires T3 and 10 according to the first embodiment, these wire-based hooping reinforcing elements of the control tire T2 are more likely to spread corrosive agents.

By comparing the control tire T3 and the tire 10 according to the first embodiment, it can be seen that, for an identical mean radial distance E1, the number of attacks Np is substantially the same. However, a much smaller total area St of the oxidation pockets is observed for the tire 10 according to the first embodiment, despite a lower value of E2 compared to the control tire T3. In accordance with the invention, this is due to the presence of wire frame elements limiting or even eliminating the spread of corrosive agents in the hooping reinforcement. By comparing the control tire T2 and the tire 10 according to the first embodiment, it is found that, for average radial distances E1 and E2 much less for the tire 10 according to the first embodiment, the tire 10 according to the first embodiment has a total area St of oxidation pockets which is not significantly greater than the total area St of oxidation pockets of the control tire T2 and in any case, the increase in the total surface St of the oxidation pockets of which is disproportionate to the lightening of the tire and disproportionate to the gain in rolling resistance.

[0172] Thus, it is concluded that by reducing E2 and/or E1 and therefore by lightening the tire and therefore by reducing its rolling resistance, it is possible to limit or even reduce the formation of oxidation pockets by using elements frame cords according to the invention preventing the spread of corrosive agents.

The invention is not limited to the embodiments described above.

It will be understood that it is possible, in order to obtain the technical effect of the invention, to further reduce the thicknesses E1 and E2. Thus, one could envisage tires in which E1<1.40 mm and even more preferably E1<1.20 mm, which would make it possible to further lighten the tire. One could also consider tires in which E2 < 0.20 mm which would, again, make it possible to further lighten the tire.

In cases where it proves necessary to reinforce the carcass reinforcement 34, it is also possible to envisage a carcass reinforcement 34 comprising two layers of carcass.

Claims

1. A tire (10) comprising a crown (12) comprising a tread (14) carrying a tread surface (15), the crown (12) comprising an axially central part (PO) extending over an axial width ( L0) equal to 50% of the axial width (L) of the tread surface (15) and axially centered on the median plane (M) of the tire (10), the axially central part (PO) of the tread ( 14) comprising at least one cutout (74, 76) deepest in the axially central part (PO) of the tread (14), the crown (12) comprising a crown reinforcement (16) comprising:

- a working reinforcement (20) comprising at least one radially outermost working layer (26) of the working reinforcement (20), the radially outermost working layer (26) comprising wire reinforcement elements of metal work (260),

- a hooping reinforcement (22) comprising several wired textile hooping reinforcing elements (220) wound helically radially around the working reinforcement (20) and connected to each other by one or more wired element(s) ( s) of weft (42), the hooping reinforcement (22) being arranged radially outside the working reinforcement (20) and radially inside the tread (14), characterized in that that, in the axially central part (PO) of the crown (12), the mean radial distance E2 between:

- the radially inner surface (104) passing through the radially innermost points of the radially innermost textile hooping wire reinforcement elements (220) among the textile hooping wire reinforcement elements (220),

- the radially outer surface (106) passing through the radially outermost points of the metallic working wire reinforcement elements (260) of the radially outermost working layer (26) of the working reinforcement (20), is such that E2 <0.40 mm, and in that the or at least one of the filamentary weft element(s) (42) comprises several textile monofilaments and/or several textile fibers chosen from monofilaments and organic polymeric synthetic fibers, monofilaments and inorganic polymeric synthetic fibers and assemblies of these monofilaments and fibers.

2. Tire (10) according to the preceding claim, in which E2 <0.30 mm, preferably E2 <0.20 mm.

3. Tire (10) according to any one of the preceding claims, in which E2>0.05 mm, preferably E2>0.10 mm.

4. A tire (10) according to any one of the preceding claims, in which the or at least one of the corded weft element(s) (42) comprises several monofilaments and/or organic polymeric synthetic textile fibers.

5. A tire (10) according to any one of the preceding claims, in which the monofilaments and the organic polymeric synthetic fibers are chosen from among the monofilaments and the polyester fibers, the monofilaments and the polyamide fibers, the monofilaments and polyketone fibres, polyurethane monofilaments and fibres, acrylic monofilaments and fibres, polyolefin monofilaments and fibres, polyetheretherketone monofilaments and fibers and assemblies of these monofilaments and these fibres, preferably among the monofilaments and the polyester fibers, the monofilaments and the polyamide fibers and the assemblies of these monofilaments and these fibers and more preferably the monofilaments and the organic synthetic fibers are monofilaments and polyester fibers.

6. Tire (10) according to any one of the preceding claims, in which, in the axially central part (PO) of the crown (12), the mean radial distance E1 between:

- the surface (100) passing through the radially innermost point of the or each deepest cutout (74, 76) of the axially central part (PO) of the tread (14) and substantially parallel to the surface of bearing (15), and

- the radially outer surface (102) passing through the radially outermost points of the most radially outer textile hooping wire reinforcement elements (220) among the textile hooping wire reinforcement elements (220), is such that E1 < 2 0.00 mm, preferably E1 <1.80 mm, more preferably E1 <1.50 mm, even more preferably E1 <1.40 mm and very preferably E1 <1.20 mm.

7. Tire (10) according to the preceding claim, in which E1>0.20 mm, preferably E1>0.50 mm and more preferably E1>1.00 mm.

8. A tire (10) according to any one of the preceding claims, in which at least one of the textile hooping wire reinforcing elements (220) is in contact with at least one of the metal working wire reinforcing elements (260). of the radially outermost working layer (26).

9. A tire (10) according to any one of the preceding claims, in which, in the axially central part (PO) of the crown (12), the mean radial distance H between:

- the surface (100) passing through the radially innermost point of the or each deepest cutout (74, 76) of the axially central part (PO) of the tread (14) and substantially parallel to the surface of bearing (15), and - the radially outer surface (106) passing through the radially outermost points of the metallic working wire reinforcement elements (260) of the radially outermost working layer (26) of the working reinforcement (20), is such that H<3.00 mm, preferably H<2.75 mm, more preferably H<2.50 mm and even more preferably H<2.35 mm.

10. A tire (10) according to any one of the preceding claims, in which the hooping reinforcement (22) is delimited axially by two axial edges (221, 222) of the hooping reinforcement (22) and comprises a strip (40) wound helically over several circumferential turns (C1, C2, C3, C4, C5) so as to extend axially between the axial edges (221, 222) of the hooping reinforcement (22).

11. Tire (10) according to the preceding claim, in which the strip (40) is wound helically over several circumferential turns (C1, C2, C3, C4, C5) so that, in the axially central part (PO ) of the crown (12), two adjacent circumferential turns (C1, C2, C3, C4, C5) of the strip (40) do not overlap axially and radially with each other.

12. A tire (10) according to claim 10 or 11, in which the strip (40) comprises several textile hooping wire reinforcement elements (220) substantially parallel to each other and embedded in a polymer matrix, preferably an elastomeric matrix. .

13. A tire (10) according to any one of the preceding claims, in which each wired textile hooping reinforcing element (220) extends along a main hooping direction (D0) forming, with the circumferential direction (X) of the tire (10), an angle, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°.

14. A tire (10) according to the preceding claim, in which the textile hooping wire reinforcing elements (220) are connected to each other by several weft wire elements (42) substantially parallel to each other along a main direction of weft (DT) non-collinear with the main hooping direction (D0), the weft wire elements (42) being discontinuous with each other.

15. A tire (10) according to claim 14, in which the main weft direction (DT) forms an angle greater than or equal to 45°, preferably greater than or equal to 75° with the main hooping direction (D0).