Bicycle tire with woven fabric casing and crown reinforcements

Abstract

The present invention relates to a tire (1) comprising a tread (6) joined by means of two sidewalls (7) to two beads (4), a composite layer (9) formed of parallel reinforcements (100) embedded in an elastomeric compound, forming a carcass reinforcement (2) by winding around a bead (8) in each bead (4) to create a inversion, said composite layer (9) extending radially outward from the carcass reinforcement (2) to form a crown reinforcement (5) comprising two crown layers (51, 52) radially superimposed internally to the tread (6), the reinforcements (100) of the composite layer (9) are connected by weft yarns (110) such that the reinforcements and the weft yarns (110) form a woven fabric whose weft yarn density is at least equal to half the density of the reinforcements. woven fabric. Figure from the abstract: Figure 1-A

Description

Title of the invention: Bicycle tire with carcass and crown reinforcements made of woven fabric Scope of the invention

[0001] The present invention relates to a bicycle tire, designed to have a carcass reinforcement and a crown reinforcement optimized for performance such as puncture resistance, and while having a minimized manufacturing cost, compared to usual designs.

[0002] Furthermore, the invention applies to all types of bicycles or bikes, such as road bikes, mountain bikes, hybrid bikes, bikes with electric motors, for example.

[0003] The invention also applies to tubeless tires, that is, tires mounted directly on a rim without an inner tube, or to tube-type tires requiring an inner tube. Definitions

[0004] By convention, we consider a frame (O, OX, OY, OZ), whose center O coincides with the center of the tire, the circumferential directions OX, axial OY, and radial OZ respectively designate a direction tangent to the rolling surface of the tire in the direction of rotation, a direction parallel to the axis of rotation of the tire, and a direction orthogonal to the axis of rotation of the tire.

[0005] By radially inside, respectively radially outside, we mean closer, respectively further from the axis of rotation of the tire.

[0006] By axially inside, respectively axially outside, we mean closer, respectively further from the equatorial plane of the tire, the equatorial plane of the tire being the plane passing through the middle of the tread of the tire and perpendicular to the axis of rotation of the tire.

[0007] The structure of a tire is usually described by a representation of its components in a meridian plane, that is, a plane containing the tire's axis of rotation. This choice is motivated by the axisymmetry of the tire's geometry around its axis of rotation. The tire also includes a plane of symmetry orthogonal to the axis of rotation and passing through the center of the tread: this is the equatorial plane.

[0008] Typically, a tire comprises a tread intended to be in contact with the ground, and radially inwardly, a crown reinforcement. The crown reinforcement and the tread constitute the crown of the tire. A carcass reinforcement radially inwardly to the crown reinforcement provides the pneumatics provide the necessary strength to carry the intended load.

[0009] An elastomeric blend is defined as an elastomeric material obtained by mixing its various constituents. An elastomeric blend typically comprises an elastomeric matrix with at least one diene elastomer of the natural or synthetic rubber type, at least one reinforcing filler of the carbon black and / or silica type, a crosslinking system most often sulfur-based, and protective agents. For certain applications, the elastomers considered may also include thermoplastics (TPEs).

[0010] The expression "based on" composition means a composition comprising the mixture and / or reaction product of the different constituents used, some of these basic constituents being capable of, or intended to, react with each other, at least in part, during the different phases of manufacturing the composition, in particular during its crosslinking or vulcanization.

[0011] The expression "part by weight per hundred parts by weight of elastomer" (or pce) is to be understood in the context of the present invention as the part, by mass per hundred parts of elastomer present in the rubber composition considered.

[0012] An elastomeric blend can be mechanically characterized, particularly after curing, by its dynamic properties, such as a dynamic shear modulus G* = (G'² + G”²)l / ², where G' is the elastic shear stiffness modulus and G” is the viscous shear modulus, and a dynamic loss Tanô = G” / G'. The dynamic shear modulus G* and the dynamic loss Tanô are measured on a Metravib VA4000 viscoalyzer, according to ASTM D 5992-96. The response of a vulcanized elastomeric blend sample in the shape of a u is recorded under a sinusoidal alternating simple shear load at a frequency of 10 Hz and a temperature of 100°C. A strain amplitude sweep is performed from 0.1% to 50% (forward cycle), then from 50% to 0.1% (return cycle). For the outward cycle, the maximum value of tan(ô) observed is indicated, denoted Tan(ô)max.

[0013] An elastomeric compound can also be characterized by static mechanical properties. Tensile tests allow the determination of elastic stresses and breaking properties. Unless otherwise specified, they are carried out in accordance with French standard NFT 46-002 of September 1988. The so-called "nominal" secant moduli (or apparent stresses, in MPa) are measured at 10% elongation (denoted "MA10") and 100% elongation ("MA100") at the second elongation (i.e., after one accommodation cycle). All these tensile measurements are carried out under normal temperature (23±2°C) and humidity (50±5% relative humidity) conditions, according to French standard NF T 40-101 (December 1979). The breaking stresses (in MPa) and elongations at break (in %) are also measured at a temperature of 23°C. Previous technique

[0014] A bicycle tire must meet a wide variety of demands depending on its intended use. Users of urban or mountain bikes have expectations related to their specific use; however, performance characteristics such as puncture resistance, pinch flats, and tire airtightness are common expectations for all users.

[0015] Furthermore, users of bicycle tires share the desire to maximize tire efficiency, which is the tire's ability to return the energy supplied by the cyclist under riding conditions. In other words, it is the ratio of the energy returned under riding conditions divided by the energy supplied by the cyclist.

[0016] This performance will depend on several factors, including the tread pattern, rolling resistance, and inflation pressure. Performance also depends on the choice of materials used and the tire's design.

[0017] Tire architecture refers to the stacking of profiles, material layers, and their relative positioning to obtain a tire that meets given technical and industrial performance specifications. The design of the architecture often proceeds through successive iterations with performance simulation phases.

[0018] According to a first known design, in the case of a carcass reinforcement comprising a single carcass layer, the free ends of each inversion can extend to the top of the tire, where they are positioned radially inside the tread and radially outside the carcass layer; furthermore, they are radially overlapped, so as to form a partial overlap of the two inversions. In an overlap design, an additional reinforcing layer, connecting the two inversions, can be positioned between the carcass layer and its inversions. For example, such an additional layer can be made of nylon fabric. This additional reinforcement improves the resistance of the carcass reinforcement to punctures and cuts, as well as to pinch impacts.

[0019] According to a second known design, each bead comprises a filling element made of an elastomeric compound, extending radially outside the bead and axially between the carcass layer and its reversal. The axial direction being the direction of the tire's axis of rotation, "axially inside, respectively outside" means "closer to, respectively farther from, the equatorial plane of the "Pneumatic, along the axial direction," the equatorial plane of the tire passing through the center of the tread and being perpendicular to the tire's axis of rotation. Such a filler element stiffens the bead. Through its deformation capacity and the decoupling it induces between the carcass layer and its inversion, it also allows for better absorption of the deformation energy generated by a pinch flat. Consequently, it is a solution that also improves resistance to pinch flats.

[0020] According to a third known design, the carcass reinforcement of a bicycle tire consists of at least two carcass layers wrapped around a bead in each bead, from the inside out, to form a inversion. Preferably, the reinforcements of one carcass layer are crossed from one carcass layer to the next, forming an angle of 45° with the circumferential direction of the tire. The free ends of the respective inversions of each carcass layer are radially overlapped, radially inside the tread, at the apex, to form an overlap. In addition, each bead includes an elastomeric compound filler element extending radially outside the bead and axially between the outermost axially external carcass layer and the corresponding innermost axially internal inversion.The combination of a carcass frame comprising at least two carcass layers and a filling element in each rim advantageously resists pinch impacts.

[0021] Document EP3797040B1 deals with bicycle tires comprising an anti-puncture system consisting of a tread with a protective layer capable of providing resistance to the penetration of foreign bodies.

[0022] However, there is a need to simplify the design of bicycle tires with the same performance while lowering the industrial production cost.

[0023] The inventors have set themselves the objective of simplifying the architecture of bicycle tires while improving endurance, more specifically resistance to puncture, without degrading the industrial production cost. Description of the invention

[0024] This goal was achieved by the design of a bicycle tire comprising a tread intended to be in contact with a road surface, said tread being joined by means of two sidewalls to two beads intended to be in contact with a rim, a composite layer formed of parallel reinforcements, making an angle between 40° and 60° with a circumferential direction, and coated in an elastomeric mixture, forming a carcass reinforcement by wrapping in each bead around a bead to achieve a reversal, said composite layer extending radially outwards from the carcass reinforcement to form a crown reinforcement comprising two crown layers radially superimposed internally to the tread, and resulting from the overlap of the ends of said composite layer, said tire is characterized in that the parallel reinforcements of the composite layer are connected by weft yarns so that the parallel reinforcements and the weft yarns form a woven fabric whose weft yarn density is at least equal to half the density of the reinforcements of the woven fabric, the yarn or reinforcement density being the number of yarns or reinforcements per decimeter.

[0025] The architecture of the tire of the invention has been simplified to the point that a single composite layer forming a woven fabric constitutes both the carcass reinforcement and the crown reinforcement. The overlapping of the two radially superimposed ends of the composite woven fabric layer forms the crown reinforcement.

[0026] The density of the reinforcements in the composite layer is determined by counting the number of parallel reinforcements per decimeter in the direction normal to that defined by the parallel reinforcements. Similarly, the density of the weft yarns in the composite layer is determined by counting the number of weft yarns per decimeter in the direction normal to the direction of the weft yarns. The direction of the weft yarns is oblique to that of the reinforcements and preferably orthogonal to the direction of the reinforcements.

[0027] The combination of the overlapping architecture of a bicycle tire and the use of a high-density woven fabric is central to the invention. A high density of weft threads is defined as a number of threads per decimeter significantly higher than usual, being at least equal to half the number of reinforcements per decimeter. In this way, the advantages of these two technologies are combined, resulting in both a simplified tire design and reduced production costs.

[0028] Innovative and unexpected technical effects give advantageous properties to the tires of the invention. The overlap architecture results in a crown reinforcement with at least three passes of the composite layer under the crown, and two passes at the sidewalls. The woven fabric of the composite layer comprises weft yarns with a count greater than 10 tex, but more importantly, said woven fabric may have a weft yarn density greater than half the density of the reinforcements.

[0029] With a high density of weft yarns, the composite layer that forms both the carcass reinforcement and the crown reinforcement constitutes, in a way, an effective mesh to protect the crown against punctures. This protective mesh is also found on the transverse walls of the tire along the sidewalls where the layer The composite passes twice due to the "overlap" architecture.

[0030] An example of reinforcement used is a single-strand nylon cable with a thread count of 47 tex. This cable is used to form a fabric with 160 reinforcements per decimeter. The weft yarn density in this example is also 160 threads per decimeter.

[0031] There are two main methods for obtaining composite fabrics used in pneumatic design. One is fabric produced by direct calendering of a network of parallel and equidistant reinforcements, which consists of applying a layer of elastomeric mixture on either side of the network of parallel reinforcements to obtain a composite layer. This is the so-called "straight grain" method.

[0032] Another approach involves connecting the reinforcements with a weft yarn, often orthogonally to the direction of said reinforcements, so that the parallel reinforcements and the weft yarns form a woven fabric. A calendering step is then carried out on both sides of the woven fabric to produce a composite layer.

[0033] The use of woven fabrics in the design of passenger car, aircraft, and agricultural tires is well-established. Weft yarns were initially introduced to improve the productivity of fabric manufacturing compared to straight grain processes. To obtain a fabric, the textile must undergo a treatment including a sizing and drying phase, followed by thermomechanical treatment before the final calendering stage. Using the textile in the form of a woven fabric facilitates these various manufacturing steps.

[0034] However, in the case of the bicycle tires of the invention, the woven fabric is characterized by a high density of weft threads and contributes to the mechanical behavior of the carcass and crown reinforcements. This additional stiffness in the plane of the woven composite layer simplifies the tire's architecture by eliminating certain material layers used in conventional designs based on straight-grain fabrics. This results in a significant reduction in the tire's mass, which translates into a direct decrease in material costs, directly impacting the tire's industrial production cost.

[0035] A mass reduction of 16% is observed on the mass of a tire of the invention.

[0036] The combination of the main features of the invention, namely the choice of The "overlap" architecture, combined with the use of a high-density woven fabric, leads to the pneumatic system of the invention which solves the technical problem stated above.

[0037] Other features of the invention related to the nature of the woven fabric on both the reinforcements and the weft yarn, combined with the "overlap" architecture, make it possible to further optimize the compromise between the technical and industrial performance of the tires of the invention.

[0038] Advantageously, the weft yarn has a count between 10 tex and 60 tex. The use of cotton weft yarn is the classic situation encountered in the woven fabric trade. For technical and economic reasons, it is advantageous for the weft yarn to be made of the same material as the reinforcements, meaning that the textile used for both the weft yarn and the reinforcement is the same. In the example mentioned earlier, with a 47-tex nylon reinforcement, the weft yarn is also nylon, but possibly with a different count.

[0039] Another surprising result is the improved sealing of the tire to retain the internal inflation air, such that the internal sealing layer, usually made of a butyl material, can be eliminated from the design of a tire of the invention. Indeed, the inventors observed that the elastomeric coating layer of the composite layer ensures effective sealing of the internal inflation air. Therefore, advantageously, the coating mixture of the reinforcements of the composite layer constitutes the internal sealing layer within the tire cavity.

[0040] Thanks to the overlap architecture, advantageously, the cross-woven crown layers are formed by the overlap of the axial ends of the composite layer forming the crown reinforcement. This superposition of woven composite layers under the crown, namely the overlap of the carcass layer plus the overlap of the axial ends of the composite layer, strengthens the tire crown against punctures. In conventional designs without woven fabrics, a protective layer is added to the crown, but in the context of this invention, this addition is no longer generally necessary. However, for very specific applications where the tires are subjected to particularly high stress, for example on off-road roads, it is advantageous for the crown reinforcement to include at least one protective composite layer, arranged radially on the outside of the crown reinforcement and radially on the inside of the tread.

[0041] Advantageously, the protective composite layer is made of the same material as the composite layer forming the top reinforcement. This means that all the constituent elements of the composite layer are identical to those of the protective composite layer (nature of the reinforcements, nature of the weft yarns, fiber counts, twist, densities, nature of the coating mixture, layer thicknesses, etc.). In this embodiment, the advantage is to standardize the materials used to reduce material costs.

[0042] Another benefit of the overlap architecture is visible through the sidewalls. Advantageously, each sidewall comprises at least two woven composite layers. As a result, the lateral protection of the tires of the invention is enhanced.

[0043] Advantageously, the rod is made of a metallic material. Two categories of pneumatic tires are distinguished, the appearance of which depends on the nature of the rods. One The first category of tires is made with metal beads, consisting of a winding of a metal wire, the number of turns depending on the size and use of the tire, and in particular its operating pressure. These tires then take their final form, that is to say, a tire forming a torus and therefore of considerable size when it comes to transport or storage.

[0044] For a second category of tire, the bead is made of a textile material. To simplify the storage and transport of bicycle tires, a second category of tires has been proposed that can be folded to reduce their size. Such tires are made with beads of a textile material that can be elastically deformed without affecting their performance when they return to their original shape. Preferably, the bead is made of an aromatic polyamide material.

[0045] Advantageously, the woven composite layer forming the carcass reinforcement, and the top reinforcement has a circumferential length between 1200 mm and 2000 mm, and an axial width between 120 mm and 450 mm.

[0046] The circumferential length of the composite layer refers to its unrolling in the circumferential direction before it is placed on the manufacturing drum. Similarly, the axial width corresponds to its axial extent.

[0047] The inventors have maximized the standardization of the materials used to manufacture a tire. A tire of the invention can be assembled with a woven composite fabric surface area of ​​only between 0.144 m² and 0.9 m². This same woven composite fabric can be used when the tire has a protective layer.

[0048] Preferably, the reinforcements of the composite layer are textile cables, each cable being obtained by twisting N strands of a textile material with a twist T2 in a given direction DI (respectively direction S or Z), with N>1, each strand resulting from overtwisting a twist T1 of a yarn of said textile material, in an opposite direction D2 (respectively Z or S).

[0049] The raw material used in the manufacture of a textile cable is yarn stored by winding onto spools weighing 4 to 12 kg. This is a flat strand composed of continuous elementary filaments, identical in both appearance and mechanical properties; said strand comes directly from the spinning mills. A yarn is generally defined by the nature of the material that constitutes the filaments (PET, Nylon, Rayon, Aramid); its linear density, expressed in tex, which represents the mass in grams of 1000 m of yarn; the number of elementary filaments constituting the yarn (200 to 1500); and the degree of interlacing of the elementary filaments.

[0050] From the yarns, double-twisted textile cables (T1, T2) are produced, which are prepared by a process called twisting, in which: - during a first step, overtwisting, each yarn or multifilament fiber (in English "yarn") constituting the final cable is first individually twisted on itself (according to an initial twist Tl) in a given direction DI (respectively direction S or Z), to form a strand in which the elementary filaments are subjected to a helical deformation around the fiber axis (or strand axis); - then, during a second stage, the twisting, several strands, generally two, three or four, of identical or different natures in the case of so-called hybrid or composite cables, are then twisted together according to a final twist T2 (which may be equal to or different from T1) in opposite direction D2 (respectively direction Z or S, according to a recognized nomenclature designating the orientation of the turns according to the crossbar of an S or a Z), to obtain the cable (in English "cord") or final assembly with several strands.

[0051] The role of twisting is to adapt the material properties in order to create transverse cohesion of the reinforcement, improve resistance to compressive stresses, and distribute stresses across all filaments. This step in the twisting process is accompanied by a decrease in breaking strength and longitudinal modulus, and an increase in fatigue strength with increasing torsion. Ultimately, the process is parameterized to obtain a compromise between fatigue resistance and breaking strength.

[0052] The cable production process continues with a gluing phase to ensure bonding between the cable and the surrounding elastomeric compound. The quality of the textile / compound interface influences the fatigue performance of the glued cable.

[0053] Advantageously, the number N of strands of a textile cable is between 1 and 6, and preferably N = 1. An example of such a cable is the N 47 / 1, which means that the cable is composed of the assembly of a strand of Nylon with a count of 47 tex.

[0054] When N=2, an industrial direct cabling process allows for overtwisting and retwisting in a single manufacturing step, resulting in a significant productivity gain. However, when N=3, overtwisting and retwisting are performed in two separate operations to produce 3-strand constructions.

[0055] Advantageously, the yarns are made up of a hybrid assembly of filaments of textile materials such as an aliphatic polyamide, a polyester, a rayon, an aromatic polyamide.

[0056] Advantageously, the fiber count of the aliphatic polyamide (Nylon) cables composing the woven composite layer is greater than or equal to 10 tex, preferably greater than or equal to 14 tex, and even more preferably greater than or equal to 47 tex, the fiber count being the linear mass of the cable, that is to say the mass expressed in grams per thousand meters of cable. Brief description of the drawings

[0057] Other details and advantageous features of the invention will become apparent from the description of exemplary embodiments of the invention with reference to the figures, which represent meridian views of diagrams of a tire according to various embodiments. The figures are not drawn to scale for the sake of simplicity.

[0058] Fig. 1 includes a view 1-A which shows a section of a tire of the invention in a meridian plane, and a view 1-B which represents a magnification of a woven fabric.

[0059] Fig. 2 shows an embodiment of the invention with the presence of a protective layer in the top reinforcement.

[0060] The [Fig.3] is a schematic diagram of the weaving to obtain the high density weft fabric of the invention.

[0061] Figure 4 comprises two views, 4-A and 4-B, showing the principle of reinforcement for the woven composite fabric of the invention. Figure 4-A illustrates the overtwisting of two aramid yarns to form two strands, showing the two possible overtwisting directions, "S" or "Z". Figure 4-B shows the retwisting of the two preceding strands to form a cable, used in a composite fabric of the invention. Detailed description of the invention

[0062] The invention has been implemented on a tire of size 25-622, according to the specification standard of the ETRTO (European Technical Organisation for Rims and Tires).

[0063] In [Fig. 1]-A, the general reference tire 1 comprises a composite layer 9 which forms a carcass reinforcement 2 and a crown reinforcement 5 with two crown layers (51, 52). The carcass reinforcement 2 consists of a first carcass layer which wraps around a bead 8 in each bead 4 so as to form a loop, and then extends into the crown reinforcement 5 to form crown layers (51, 52) made up of the axial ends of the composite layer 9. The bead 4s are connected to the tread 6 by means of two sidewalls 7.

[0064] Fig. 1-B represents a piece of woven fabric with reinforcing threads 100 in textiles connected orthogonally by weft threads 110.

[0065] The [Fig.2] is an embodiment of the invention where a protective layer 10 reinforces the top reinforcement 5, positioned radially externally to the top layers.

[0066] Figure 3 shows the principle of the general reference weaving process 200 for obtaining the woven fabric 9. The cable reels 220 are installed in the creel 210 which, after unwinding the cables, provides a network of parallel cables 100. A cable separation system 250 precedes the passage through the reed 240 for the insertion of the weft yarns 110. The particularity here is having, on the one hand, a high density of weft yarns which is greater than half the cable density of the fabric, and on the other hand, the weft yarns and the cables are of the same type.

[0067] Fig. 4 shows views 4-A and 4-B. View 4-A shows two strands obtained, one by an S-twisting and the other by a Z-twisting of yarns composed of bundles of textile filaments.

[0068] Fig. 4-C illustrates the principle of manufacturing the textile cable, with, for example, the overtwisting of two yarns in a Z shape, which are then twisted in the opposite direction in an S shape to obtain a cable.

[0069] The dimensional data of the tire manufactured according to the invention show a sidewall height of 35 mm and a bead width of 25 mm. The angles of the reinforcements of the top layers with the circumferential direction vary from 40° to 60°. The bead is made of textile with an assembly of 18 aramid threads.

[0070] The tire is used with an inflation pressure of 800 kPa.

[0071] The composite layer constituting the carcass and top reinforcements is made of Nylon 6.6 reinforcements with a count of 47 tex. These nylon reinforcements are single-strand cables. Their breaking strength is 2.3 daN at 23% elongation, and the cable density of one composite layer is 40 threads per inch. The cable diameter is 0.39 mm, and the composite layer has a thickness of 0.41 mm. The weft threads connecting the cables are also made of Nylon with a count of 47 tex. The weft thread density of the woven composite layer is 40 threads per inch.

[0072] For the studied pneumatic dimension, the circumferential length of the composite layer forming the carcass and crown reinforcement is 1944 mm, and its axial width is 168 mm. These dimensions of the composite layer are sufficient to form both the carcass and crown reinforcements. These values ​​guarantee optimal performance of the composite layer as both carcass and crown reinforcement.

[0073] The elastomeric coating compound for the composite layer has a composition as described below in the following table:

[0074] [Tables 1] Compositions: NR (Natural Rubber) Elastomer, Non-reinforcing filler, Protective agent, Vulcanizing agent, Composite layer coating mix, Kaolin (25 pcs), Wax / SP C (5.5 pcs), S (2.75 pcs), CBS (1.05 pcs)

[0075] The coating mixture of the composite layer forming the carcass and top reinforcement is characterized by the following mechanical properties:

[0076] [Tables2] Composite layer coating mix Properties Modulus of stiffness G* 0.74 G' (MPa) 0.73 tan (φ) 0.04

[0077] The thickness of the cable coating layer of the composite layer is less than or equal to 0.1 mm.

[0078] Tire configurations of the invention have been tested to clearly highlight the performance provided by the invention. The results of these tests are compared to those obtained on a reference tire of the same size, namely: 25-622.

[0079] The witness T conforms to the diagram in [Fig. 1]-A, and corresponds to a conventionally designed tire with an overlap architecture, but without a woven fabric. This tire differs from the invention in that the composite layer forming the carcass reinforcement and the crown reinforcement is not a woven fabric, but a straight-grain fabric.

[0080] First, an endurance test was carried out on each of the tires. This test consists of measuring the resistance to failure of a tire in contact with a rotating flywheel, equipped with severance bars and subjected to cycles of stress in loads, pressure and speed.

[0081] The "breaking energy" test, also known as the polar test, consists of pushing a polar into the sidewall of a tire inflated to the nominal pressure and mounted on a measuring rim. The applied force is measured at the point where the sidewall breaks.

[0082] Rolling resistance tests were carried out according to the principles of ISO 28580. For a tested tire, the result is the rolling resistance coefficient which represents the ratio of the force resisting the forward movement of the vehicle due to tire hysteresis divided by the load carried.

[0083] A leak test comparing the test tire and the tire of the invention was carried out. The test consists of mounting a tire on a rim, inflating it to a set pressure and monitoring the evolution of the internal pressure over time.

[0084] A result greater than (respectively less than) 100% means an improvement (respectively a degradation) of the performance considered.

[0085] The results obtained are summarized in the following table:

[0086] [Tables3] Endurance Mass Rolling resistance Sealing Breaking Energy Sidewall Indicator 100 100 100 100 100 Tire invention 100 116 105 200 120

[0087] The tires of the invention are at an identical level of performance in endurance, but they are distinguished from the state of the art by the advantageous compromise of performances other than endurance such as rolling resistance and especially the sealing against leakage of the internal inflation air, the mass and by a very significant gain in industrial production cost.

[0088] The invention can also be applied, for example, to motorized two-wheeled vehicles, wheelchairs or strollers.

Claims

Claims

1. A bicycle tire (1) comprising a tread (6) intended to be in contact with a rolling surface, said tread (6) being joined by means of two sidewalls (7) to two beads (4) intended to be in contact with a rim, a composite layer (9) formed of reinforcements (100) parallel to each other, making an angle of between 40° and 60° with a circumferential direction, and coated in an elastomeric mixture, forming a carcass reinforcement (2) by winding in each bead (4) around a bead wire (8) to produce a turn-over, said composite layer (9) extending radially outside the carcass reinforcement (2) to form a crown reinforcement (5) comprising two crown layers (51, 52) radially superimposed inside the tread (6), and resulting from the overlapping of the ends of said composite layer (9),said tire (1) is characterized in that the parallel reinforcements (100) of the composite layer (9) are connected by weft threads (110) so that the parallel reinforcements (100) and the weft threads (110) form a woven fabric whose density of weft threads is at least equal to half the density of the reinforcements of the woven fabric, the density of threads or reinforcements being the number of threads or reinforcements per decimeter.,

2. Tire (1) according to claim 1 wherein the weft yarn (110) has a count between 10 tex and 60 tex.

3. Tire (1) according to the preceding claim in which the weft thread (110) is made of a material of the same nature as the reinforcements (100).

4. Tire (1) according to one of the preceding claims, in which the coating mixture of the reinforcements (100) of the composite layer (9) constitutes the internal sealing layer in the cavity of the tire (1).

5. Tire (1) according to one of the preceding claims in which the crown reinforcement (5) comprises at least one composite protective layer (10), arranged radially outside the crown reinforcement (5), and radially inside the tread (6).

6. Tire (1) according to claim 5 wherein the protective composite layer (10) is made of the same material as the composite layer (9) forming the crown reinforcement (5).

7. Tire (1) according to one of the preceding claims in which each sidewall (7) comprises at least two composite woven layers.

8. A tire (1) according to any preceding claim wherein the bead wire (8) is made of a metallic material.

9. Tire (1) according to one of claims 1 to 7 in which the bead wire (8) is made of a textile material.

10. A tire (1) according to claim 9 wherein the bead wire (8) is made of an aromatic polyamide material.

11. Tire (1) according to one of the preceding claims in which the composite layer (9) formed by weaving the carcass reinforcement (2), and the crown reinforcement (5) has a circumferential length of between 1200 mm and 2000 mm.

12. Tire (1) according to one of the preceding claims in which the composite layer (9) formed by weaving the carcass reinforcement (2), and the crown reinforcement (5) has an axial width of between 120 mm and 450 mm.

13. Tire (1) according to one of the preceding claims, in which the reinforcements (100) of the composite layer (9) are textile cables, each cable being textile obtained by twisting a twist T2 of N strands of a textile material in a given direction DI (respectively direction S or Z), with N>1, each strand resulting from overtwisting a twist T1 of a yarn of said textile material, in an opposite direction D2 (respectively Z or S).

14. Tire (1) according to claim 13, in which the number N of strands of each textile cable is between 1 and 6, and preferably N is equal to 1.

15. Tire (1) according to one of claims 13 to 14 in which the yarns are made up of a hybrid assembly of filaments of textile materials such as an aliphatic polyamide, a polyester, a rayon, an aromatic polyamide. Tire (1) according to one of claims 13 to 15, in which the count of the aliphatic polyamide (Nylon) cables making up the woven composite layer (9) is greater than or equal to 10 tex, preferably greater than or equal to 14 tex, and even more preferably, greater than or equal to 47 tex, the count being the linear mass of the cable, that is to say the mass expressed in grams per thousand meters of cable.

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