WO2016202622A1

WO2016202622A1 - Multi-strand metal cable

Info

Publication number: WO2016202622A1
Application number: PCT/EP2016/062806
Authority: WO
Inventors: Natacha PIRONNEAU; Emmanuel Clement; Thibault RAPENNE
Original assignee: Compagnie Generale Des Etablissements Michelin; Michelin Recherche Et Technique S.A.
Priority date: 2015-06-16
Filing date: 2016-06-06
Publication date: 2016-12-22
Also published as: FR3017885A1

Abstract

The two-layer multi-strand cable (31) comprises: - an inner layer (CI) of the cable (31) consisting of an inner strand (TI), - and a compact outer layer (CE) of the cable (31) consisting of L>1 outer strands (TE). Each internal and external strand (TI, TE) comprises an internal layer and an external layer of wires. The inter-wire distance D3' of the wires of the external layer of each external strand (TE) is greater than or equal to 25 µm.

Description

Multi-strand wire rope

[001] The invention relates to multi-strand cables used in particular for the reinforcement of tires, particularly tires for heavy industrial vehicles.

[002] A radial carcass reinforcement tire comprises a tread, two inextensible beads, two flanks connecting the beads to the tread and a belt, or crown reinforcement, arranged circumferentially between the carcass reinforcement and the band. rolling.

[003] This crown reinforcement comprises several rubber plies, possibly reinforced by reinforcing elements such as cables or monofilaments, of metal or textile type.

[004] The crown reinforcement generally comprises at least two superimposed vertex plies, sometimes called working plies or crossed plies, whose reinforcement elements, generally metallic, are arranged substantially parallel to each other inside the plywood. a web, but crossed from one web to another, that is to say inclined, symmetrically or otherwise, with respect to the median circumferential plane, an angle which is generally between 10 ° and 45 °. The working plies generally comprise reinforcement elements having a very low elongation so as to ensure their function of guiding the tire.

[005] The crown reinforcement may also comprise various other layers or layers of auxiliary rubber, of variable widths depending on the case, with or without reinforcing elements. By way of example, mention may be made of so-called protection plies responsible for protecting the rest of the belt from external aggressions, perforations, or so-called shrinking plies comprising reinforcement elements oriented substantially in the circumferential direction, whether they are radially external or internal with respect to the working plies. The protective plies generally comprise reinforcing elements having a high elongation so as to be deformed under the effect of a stress exerted by an indenter, for example a rock.

[006] The carcass reinforcement comprises, in turn, at least one rubber ply, said working, reinforced by reinforcing elements such as metal cables. A working sheet reinforcement element comprising a multi-strand wire rope with two layers of structure 189.23 is known from the state of the art. This cable comprises an inner layer of the cable consisting of an inner strand and an outer layer of the cable consisting of six outer strands wound helically around the inner layer of the cable. [007] Each inner and outer strand comprises an inner layer of the strand consisting of three internal son, an intermediate layer consisting of nine son and an outer layer of the strand consisting of fifteen external son. Each wire has a diameter equal to 0.23 mm.

[008] A tire of heavy industrial vehicle, including civil engineering, is subject to many attacks. Indeed, the rolling of this type of tire is usually done on a rough surface sometimes leading to perforations of the tread. These perforations allow the entry of corrosive agents, for example air and water, which oxidize the metal reinforcing elements of the crown reinforcement and sometimes of the carcass reinforcement, which considerably reduces the service life. of the tire.

[009] Concerning the carcass reinforcement, the inventors at the origin of the invention have identified that the most detrimental effect of the corrosive agents was not so much the alteration of the mechanical properties of the cable, in particular its force at rupture, that the loss of adhesion between the wires located at the periphery of the cable (the outer wires of the outer strands) and the adjacent rubber subsequent to the corrosion of the adhesion interface by these corrosive agents. When it occurs, this loss of adhesion leads to a separation of the cable of its adjacent eraser. Once disconnected, the cable then slides in a sheath formed by the adjacent rubber and no longer takes the forces exerted on the tire.

[010] A solution to increase the life of the tire is to fight against the action of corrosive agents within each strand. It is thus possible to cover each inner and intermediate layer of each strand with gum during the cable manufacturing process. During this process, the deposited gum penetrates the capillaries present between each layer of each strand and thus prevents the propagation of corrosive agents. Such cables, generally called cables gummed in situ, are well known in the state of the art. However, the manufacturing process of these cables gummed in situ requires control of many industrial constraints to avoid including the overflow of the eraser at the periphery of each strand.

Another solution to increase the life of the tire is to increase the breaking force of the cables of the state of the art. Generally, the breaking force is increased by increasing the diameter of the wires constituting the cable and / or the number of wires and / or the unit resistance of each wire. However, further increasing the diameter of the wires, for example beyond 0.50 mm, necessarily causes a decrease in the flexibility of the cable which is not desirable for a cable used in the carcass reinforcement. Increasing the number of wires leads to most of the time a decrease in the penetrability of the strands by the rubber. Increasing the unit resistance of each wire requires significant investment in wire manufacturing facilities. However, increasing the breaking force also does not compensate for the loss of adhesion between each metallic reinforcing element and the adjacent mixture.

The object of the invention is to provide a cable having improved breaking force and adhesion compared with cables of the state of the art while avoiding the aforementioned disadvantages.

[013] For this purpose, the subject of the invention is a multi-strand cable with two strand layers, comprising:

an inner layer of the cable consisting of a single inner strand,

an outer layer of the compact cable consisting of L> 1 outer strands, each inner and outer strand comprising:

an internal and external strand inner layer consisting respectively of M and M 'internal wire (s),

an outer layer of the inner and outer strand respectively consisting of P and P 'external wires wound helically around each inner layer respectively of the inner and outer strand,

wherein the interfering distance D3 'of the outer layer wires of each outer strand is greater than or equal to 25 μηη.

[014] The cable according to the invention has a breaking force and an improved adhesion with respect to cables of the state of the art 189.23 while avoiding the disadvantages described above.

[015] Beforehand, it is necessary to recall that, in the cable 189.23 of the state of the art, the outer strands are contiguous and thus form a vault around the inner strand giving the cable a relatively high breaking force. Breaking this vault, for example by increasing the diameter of the inner strand relative to those of the outer strands, would result, unless further modification, in a drop in the breaking force. Indeed, by removing the vault around the inner strand, the outer son of each outer strand would, during the pulling of the cable, exert a radial force directed towards the inside of the cable on the outer son of the inner strand while the arch allowed a distribution of this force both in a longitudinal component between the outer strands and in a radial component between the outer strands and the inner strand.

[016] In the cable according to the invention, as the outer layer of the cable is compact, the inventors at the origin of the invention have maintained the vault, thus giving the cable a relatively high breaking strength or higher than the cables of the state of the art.

[017] By definition, a compact layer is such that there is theoretically no gap of the gum between the strands of the layer.

[018] In addition, unlike the cables of the state of the art, the inventors at the origin of the invention discovered that adhesion problems could be solved using external strands highly penetrable by the eraser, each outer strand comprising an outer layer having a relatively high interfering distance D3 '. Indeed, the gum penetrating the outer strands relatively well between the son of the outer layer, the latter prevents the action of corrosive agents between the adjacent mixture and this outer layer. Thus, the cable according to the invention thus cooperates with the rubber to take up the forces exerted on the tire and is therefore more resistant to compression.

[019] In addition, even if the outer layer of the cable is compact, the rubber manages to penetrate, through the outer strands, into contact with the inner strand because of the interfilar distance D3 'relatively high. Thus, it limits the propagation of corrosive agents along the cable while maintaining the vault created by the outer strands and thus the high breaking force of the cable.

[020] The interleaf distance of a layer is defined, on a section of the cable perpendicular to the main axis of the cable, as the smallest distance separating, on average on said layer, two adjacent son of said layer. Thus, channels allow the passage of the gum through the outer layer to effectively penetrate the eraser in each outer strand but also through the outer strands to reach the inner strand.

[021] Preferably, each wire of the cable is metallic. The invention is preferably implemented with steel wires, more preferably carbon pearlitic (or ferritic-pearlitic) steel, hereinafter referred to as "carbon steel", or else stainless steel (by definition, steel comprising at least one minus 1 1% chromium and at least 50% iron). But it is of course possible to use other steels or other alloys.

[022] When carbon steel is used, its carbon content (% by weight of steel) is preferably between 0.4% and 1.2%, especially between 0.5% and 1.1%. ; these levels represent a good compromise between the mechanical properties required for the tire and the feasibility of the wires. It should be noted that a carbon content of between 0.5% and 0.6% makes such steels ultimately less expensive because easier to draw. Another advantageous embodiment of the invention may also consist, depending on the applications concerned, of using steels with a low carbon content, for example between 0.2% and 0.5%, in particular because of a cost lower and easier to draw.

[023] The metal or steel used, whether it is in particular a carbon steel or a stainless steel, may itself be coated with a metal layer improving, for example, the setting properties. implementation of the wire rope and / or its constituent elements, or the properties of use of the cable and / or the tire themselves, such as adhesion properties, corrosion resistance or resistance to aging.

[024] According to a preferred embodiment, the steel used is covered with a layer of brass (Zn-Cu alloy) or zinc. It is recalled that during the manufacturing process of the son, the coating of brass or zinc facilitates the drawing of the wire, as well as the bonding of the wire with the eraser. But the son could be covered with a thin metal layer other than brass or zinc, having for example the function of improving the corrosion resistance of these son and / or their adhesion to the gum, for example a thin layer Co, Ni, Al, an alloy of two or more of Cu, Zn, Al, Ni, Co, Sn.

[025] The skilled person knows how to manufacture steel son having such characteristics, in particular by adjusting the composition of the steel and the final work hardening rates of these son, according to his own particular needs, in for example using micro-alloyed carbon steels containing specific addition elements such as Cr, Ni, Co, V, or various other known elements (see for example Research Disclosure 34984 - "Micro-alloyed steel cord constructions for tires" - May 1993, Research Disclosure 34054 - "High tensile strength steel cord constructions for tires" - August 1992).

[026] Preferably, each strand is of the tubular or cylindrical layer type. The term "tubular or cylindrical layer strand" thus means strands consisting of a core comprising an inner layer, and optionally a core or a core, and one or more concentric layers, here the intermediate and outer layers, each of form cylindrical or tubular, arranged around this core, such that, at least in the strand at rest, the thickness of each intermediate and outer layer is substantially equal to the diameter of the son constituting it; As a result, the cross section of the strand has a substantially circular outline or envelope.

[027] Thus, the strands with cylindrical or tubular layers should not in particular be confused with so-called "compact" strands, wire assemblies wound at the same pitch and in the same direction of winding. In such compact strands, the compactness is such that virtually no distinct layer of wires is visible; it follows that the cross section of such strands has an outline that is no longer circular, but polygonal.

[028] A tubular or cylindrical layer strand, also called non-compact strand, is a strand in which at least two layers of strands have a pitch or direction of winding different from each other.

[029] Preferably, the son of the same layer of a predetermined strand (internal or external) all have a substantially identical diameter. In particular, all the son of the same strand all have a substantially identical diameter. Advantageously, the outer strands are substantially all identical and in particular all have a substantially identical diameter. "Substantially identical" or "substantially equal" means that the yarns and strands respectively have diameters equal to the close industrial tolerances, that is to say that the difference between the diameter of the smallest yarn, respectively the smaller strand, and the largest wire, respectively the largest strand, is less than or equal to 10% compared to the average value of the diameters of the strands or strands respectively.

[030] Advantageously, the interfilential distance D'3 is greater than or equal to 30 μηη, preferably 35 μηη and more preferably 40 μηη. By increasing the interfering distance D3 ', the passage of the gum through the outer layer and thus the adhesion with the adjacent mixture and, on the other hand, the penetrability of the cable by the rubber.

[031] Preferably, the diameter Dl of each inner strand is substantially equal to the diameter DE of each outer strand.

[032] In one embodiment, L = 6.

[033] In one embodiment, each inner and outer strand comprises an intermediate layer of the inner and outer strand respectively consisting of N and N 'intermediate wires spirally wound around each inner layer respectively of the inner and outer strand, the outer layer. inner and outer strand being wound helically around each intermediate layer respectively of the inner and outer strand.

[034] Advantageously, Μ = Μ ', N = N' and P = P '. Thus, the cable is industrially easier to manufacture.

[035] Advantageously, the interfering distance D2 'of the wires of the intermediate layer of each outer strand is greater than or equal to 25 μηι, preferably 30 μηη and more preferably 35 μηη. By increasing the interfering distance D2 ', the passage of the gum through the intermediate layer is favored. This prevents or even prevents the propagation of corrosive agents from the inner layer of the strand to the outer layer of the strand and thus the adhesion with the strand is further preserved. adjacent mixture.

[036] In a preferred embodiment, D3 '> D2'. As the adhesion between the cable and the adjacent mixture is predominantly between the adjacent mixture and the outer layer of each strand, the adhesion is maximized by promoting the passage of the gum between the strands of the outer layer with respect to its passage between the son of the middle layer.

[037] In an advantageous embodiment, the ratio D27D3 'satisfies 0.5 <D27D3' <1, 5, preferably 0.7 <D27D3 '<1, 3, more preferably 0.8 <D27D3' <1, 2. The passage channels of the eraser comprise an external opening allowing the rubber to penetrate from the outside of the cable towards the inside of the cable and an internal opening allowing the rubber to open into the heart of the cable, for example in contact with the cable. inner layer. In order to ensure maximum penetration of the rubber, the outer and inner openings preferably have relatively close dimensions. Thus, the penetration of the rubber is optimized by avoiding that one of the external and internal openings of each passage channel limits the flow of gum.

[038] Advantageously, each inter-son distance D2 ', D3' is less than or equal to 100 μηι, preferably 60 μηι.

[039] Optionally, the intermediate layer of each outer strand is non-compact and unsaturated.

[040] Optionally, the outer layer of each outer strand is non-compact and unsaturated.

[041] Non-compact layer means that each wire of the layer is distant from the son of the layer that are adjacent thereto. Thus, each wire of the layer is, in the case of a homogeneous distribution of the son of the layer, not in contact with the son of the layer that are adjacent thereto.

[042] By definition, an unsaturated layer of son is such that there is sufficient space in this layer to add at least one (X + 1) th thread of the same diameter as the X son of the layer, several son can then be in contact with each other.

[043] Preferably, N 'and P' are such that N '+ P'> 22.

[044] Thus, the breaking force of the cable is maximized by using a large number of wires on the outer and intermediate layers to take up the pressures. Indeed, when pulling the cable the outer son of each outer strand come to exert a radial force directed towards the inside of the cable on the outer son of the inner strand. By using a sufficient number of wires on the outer layers of each inner and outer strand, it is ensured that the radial force is sufficiently distributed to reduce the pressure on each single wire. However, the presence of a large number of wires does not prevent the penetrability of the outer layers of the outer strands which ensures good adhesion with the adjacent mixture.

[045] Preferably, M '= 2, 3 or 4, N' = 7, 8, 9 or 10 and P '= 13, 14, 15 or 16.

[046] In one embodiment, P '= 14 or 15. Thus, each outer strand is preferably of structure 2 + 7 + 14, 2 + 7 + 15, 2 + 8 + 14, 2 + 8 + 15, 2 + 9 + 14, 2 + 9 + 15, 2 + 10 + 14, 2 + 10 + 15, 3 + 7 + 14, 3 + 7 + 15, 3 + 8 + 14, 3 + 8 + 15, 3 + 9 + 14, 3 + 9 + 15, 3 + 10 + 14, 3 + 10 + 15, 4 + 7 + 14, 4 + 7 + 15, 4 + 8 + 14, 4 + 8 + 15, 4+ 9 + 14, 4 + 9 + 15, 4 + 10 + 14, 4 + 10 + 15.

[047] In one embodiment, M '= 2, N' = 7, 8, 9 or 10 and P '= 13, 14, 15 or 16, preferably M' = 2, N '= 7, 8 or 9 and P-14, and more preferably M '= 2, N' = 9 and P '= 14. Thus, each outer strand preferably has a structure 2 + 7 + 14, 2 + 8 + 14 and 2 + 9 + 14 and more preferably a structure 2 + 9 + 14.

[048] In another embodiment, M '= 3, N' = 7, 8, 9 or 10 and P -13, 14, 15 or 16, preferably M '= 3, N' = 8 or 9 and P-14 or 15, and more preferably M '= 3, N' = 9 and P '= 14. Thus, each outer strand preferably has a structure 3 + 8 + 14, 3 + 9 + 14, 3 + 8 + 15, 3 + 9 + 15 and more preferably a structure 3 + 9 + 14.

[049] In another embodiment, M '= 4, N' = 7, 8, 9 or 10 and P -13, 14, 15 or 16, preferably M '= 4, N' = 7, 8, 9 or 10 and P-14 or 15, and more preferably M '= 4, N' = 9 and P-14. Thus, each outer strand preferably has a structure 4 + 7 + 14, 4 + 7 + 15, 4 + 8 + 14, 4 + 8 + 15, 4 + 9 + 14, 4 + 9 + 15, 4+ 10 + 14, 4 + 10 + 15 and more preferably a 4 + 9 + 14 structure.

[050] Advantageously, each diameter d1 ', d2', d3 'of each wire respectively of each inner, intermediate and outer layer of each outer strand satisfies 0.15 <d1 \ d2 \ d3' <0.5 mm, preferably 0.18 <d1 \ d2 \ d3 '<0.30 mm, more preferably 0.20 <d1', d2 ', d3' <0.28 mm. These diameters make it possible to obtain an optimized compromise of compressive strength and endurance when the cable is used in particular in a carcass reinforcement.

[051] Preferably, each diameter d2 ', d3' of each wire respectively of each intermediate and outer layer of each outer strand satisfies d2 '= d3'.

[052] Preferably, each diameter d1 ', d2' of each wire respectively of each inner and intermediate layer of each outer strand verifies d1 '= d2'.

[053] In a variant, provision may be made for d1 '>d2'. Thus, this makes it possible to reinforce the intermediate layer by adding a wire with respect to the case where d1 '= d2' and thus to increase the breaking force of the cable. This also makes it possible to further increase the unsaturation of the outer layer with respect to the case where d1 '= d2' and thus to further improve the adhesion with the adjacent mixture. [054] Advantageously, each diameter d1, d2, d3 of each wire respectively of each inner, intermediate and outer layer of each inner strand satisfies 0.15 <d1, d2, d3 <0.5 mm, preferably 0.18 < d1, d2, d3 <0.30 mm, more preferably 0.20 <d1, d2, d3 <0.28 mm. These diameters make it possible to obtain an optimized compromise of resistance and endurance when the cable is used in particular in a carcass reinforcement.

[055] Preferably, each diameter d2, d3 of each wire respectively of each intermediate and outer layer of each inner strand verifies d2 = d3.

[056] Preferably, each diameter d1, d2 of each wire respectively of each inner and intermediate layer of each inner strand verifies d1 = d2.

[057] In a variant, provision may be made for d1> d2. Thus, this reinforces the intermediate layer by adding a wire relative to the case where d1 = d2 and thus increase the breaking strength of the cable. This also makes it possible to further increase the unsaturation of the outer layer with respect to the case where d1 = d2 and thus to further improve the adhesion with the adjacent mixture.

[058] Preferably, N and P are such that N + P> 22.

[059] Preferably, M = 2, 3 or 4, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16.

[060] In one embodiment, P = 14 or 15. Thus, each inner strand is preferably of structure 2 + 7 + 14, 2 + 7 + 15, 2 + 8 + 14, 2 + 8 + 15 , 2 + 9 + 14, 2 + 9 + 15, 2 + 10 + 14, 2 + 10 + 15, 3 + 7 + 14, 3 + 7 + 15, 3 + 8 + 14, 3 + 8 + 15, 3 + 9 + 14, 3 + 9 + 15, 3 + 10 + 14, 3 + 10 + 15, 4 + 7 + 14, 4 + 7 + 15, 4 + 8 + 14, 4 + 8 + 15, 4 + 9 +14, 4 + 9 + 15, 4 + 10 + 14, 4 + 10 + 15.

[061] In one embodiment, M = 2, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16, preferably M = 2, N = 7, 8 or 9 and P = 14 , and more preferably M = 2, N = 9 and P = 14. Thus, each inner strand preferably has a structure 2 + 7 + 14, 2 + 8 + 14 and 2 + 9 + 14 and more preferably a structure 2 + 9 + 14.

[062] In another embodiment, M = 3, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16, preferably M = 3, N = 8 or 9 and P = 14 or 15. Thus, each inner strand preferably has a structure 3 + 8 + 14, 3 + 9 + 14, 3 + 8 + 15, 3 + 9 + 15 and more preferably a structure 3 + 9 + 14.

[063] In another embodiment, M = 4, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16, preferably M = 4, N = 7, 8, 9 or 10 and P = 14 or 15, and more preferably M = 4, N = 9 and P = 14. Thus, each inner strand preferably has a structure 4 + 7 + 14, 4 + 7 + 15, 4 + 8 + 14, 4 + 8 + 15, 4 + 9 + 14, 4 + 9 + 15, 4+ 10 + 14, 4 + 10 + 15 and more preferably a 4 + 9 + 14 structure.

[064] Advantageously, the inter-wire distance D2 of the wires of the intermediate layer of each inner strand is greater than or equal to 25 μηι, preferably 30 μηι, more preferably 35 μηη. [065] Advantageously, the inter-wire distance D3 of the wires of the outer layer of each inner strand is greater than or equal to 25 μηι, preferably 30 μηι, more preferably 35 μηη and even more preferably 40 μηη.

[066] Thus, the rubber can penetrate inside each inner strand to slow down, or even prevent the propagation of corrosive agents within each inner strand.

[067] Advantageously, each inter-son distance D2, D3 is less than or equal to 100 μηι, preferably 60 μηι.

[068] Optionally, the intermediate layer of each inner strand is non-compact and unsaturated.

[069] Optionally, the outer layer of each inner strand is non-compact and unsaturated.

[070] In a preferred embodiment, the son, including the son of the inner layer of each inner and / or outer strand, are non-preformed. By avoiding preformation, it avoids the industrial steps necessary for preforming the son.

The complexity of the process is reduced while maintaining a cable having high breaking strength and excellent adhesion with the adjacent mixture.

[071] For the following, it is recalled that, in a known manner, the pitch represents the length, measured parallel to the axis of the cable, at the end of which a wire having this step performs a complete revolution about said axis of the cable.

[072] According to optional features independent of each other relating to the pitch of each wire of each layer:

The wires of the inner layer of each inner strand are wound at a pitch p1 which satisfies 4 <p1 <11 mm, preferably 5 <p1 <9 mm.

The wires of the inner layer of each outer strand are wound at a pitch p1 'which satisfies 4 <p1' <11 mm, preferably 5 <p1 '<9 mm.

The wires of the intermediate layer of each inner strand are wound at a pitch p2 which satisfies 6 <p2 <20 mm, preferably 8 <p2 <18 mm.

The wires of the intermediate layer of each outer strand are wound at a pitch p2 'which satisfies 6 <p2' <20 mm, preferably 8 <p2 '<18 mm.

The wires of the outer layer of each inner strand are wound at a pitch p3 which satisfies 10 <p3 <30 mm, preferably 14 <p3 <22 mm.

The wires of the outer layer of each outer strand are wound at a pitch p3 'which checks 10 <p3' <30 mm, preferably 14 <p3 '<22 mm.

[073] According to another optional feature, the outer strands are wound at pitch P which satisfies 30 <P <80 mm, preferably 40 <P <70 mm.

[074] Preferably, the cable comprises a hooping layer comprising a wire of fret wrapped around the outer layer of the cable. In a variant, the cable does not have a shrinking layer.

[075] In the case where it is desired to confer on the cable, in addition to the self-locking properties described above, an even further improved compressive strength, a frettage layer is added which relieves the outer layer of the cable. vis-à-vis the compression and thus improves the endurance of the cable.

[076] Such a hooping layer consists for example of a single wire, metallic or not, coated or not with a metal layer, for example brass. It is advantageous to choose a stainless steel hoop wire in order to reduce the fretting wear of the wires of the outer layer of the outer strands in contact with the stainless steel hoop, the stainless steel wire possibly being replaced, in an equivalent manner. , by a composite thread of which only the skin is made of stainless steel and the core made of carbon steel.

[077] Preferably, the winding direction of the wire of the hooping layer is different from the winding direction of the outer strands.

[078] In one embodiment, the outer wires of the outer layer of each outer strand are wound in a winding direction identical to that of the outer wires of the outer layer of each inner strand.

[079] Optionally, the outer strands are wound around the inner strand in a winding direction opposite to that of the outer wires of the outer layer of each outer strand.

[080] Another object of the invention is a tire comprising at least one cable as defined above.

[081] Preferably, the tire comprises a carcass reinforcement anchored in two beads, said carcass reinforcement comprising at least one reinforcing element, called carcass, comprising a cable as defined above.

[082] Advantageously, the carcass reinforcement comprises at least one carcass ply comprising reinforcement elements, referred to as carcass elements, the carcass reinforcement elements making an angle greater than or equal to 65 °, preferably 80 ° relative to to the circumferential direction of the tire.

[083] The cable is particularly intended for industrial vehicles chosen from heavy vehicles such as "heavy goods vehicles" - ie, metro, buses, road transport vehicles (trucks, tractors, trailers), off-the-road vehicles - agricultural or civil engineering machinery, other transport or handling vehicles.

[084] In a preferred embodiment, the tire has a WRU-type dimension with U≥35, preferably U≥49 and more preferably U≥57. So, preferably, the tire is for civil engineering type vehicle. Thus, the tire has a dimension in which the diameter, in inches, of the seat of the rim on which the tire is to be mounted is greater than or equal to 35 inches, preferably 49 inches and more preferably 57 inches.

[085] In one embodiment, the tire comprises a crown reinforcement arranged radially inside the tread and radially outside the carcass reinforcement, the crown reinforcement comprising:

- a protective armor, and

a working armature arranged radially inside the protective armature.

[086] In one embodiment, the protective armature is interposed radially between the tread and the armature work.

[087] Advantageously, the protective reinforcement comprising at least one protective ply comprising reinforcing elements, said protective elements, the protective reinforcing element or elements forming an angle of at least 10 °, preferably ranging from 10 ° at 35 ° and more preferably from 15 ° to 30 ° with the circumferential direction of the tire.

[088] In one embodiment, the working reinforcement comprising at least one working ply comprising so-called working reinforcement elements, the work reinforcing elements forming an angle at most equal to 60 °, preferably ranging from from 15 ° to 40 ° with the circumferential direction of the tire.

[089] Advantageously, the crown reinforcement comprises a hooping reinforcement comprising at least one hooping sheet.

[090] In one embodiment, each hoop comprises reinforcing elements, said hooping elements, the hooping reinforcing elements making an angle at most equal to 10 °, preferably ranging from 5 ° to 10 ° with the circumferential direction of the tire.

[091] Preferably, the hooping frame is arranged radially inside the working frame and radially outside the carcass reinforcement. [092] The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings in which:

Figure 1 is a sectional view perpendicular to the circumferential direction of a tire according to the invention;

FIG. 2 is a detailed view of zone I of FIG. 1;

Figure 3 is a schematic sectional view perpendicular to the axis of the cable (assumed rectilinear and at rest) of a cable according to the invention;

Figure 4 is a schematic view similar to that of Figure 3 of the inner strand of the cable according to the invention;

Figure 5 is a schematic view similar to that of Figure 3 of an outer strand of the cable according to the invention;

Figure 6 is a photograph of the cable according to the invention of Figure 3; and Figure 7 is a photograph similar to that of Figure 6 of the prior art cable 189.23. [093] EXAMPLE OF PNEUMATIC ACCORDING TO THE INVENTION

[094] Any range of values designated by the expression "from a to b" means the range of values going from the "a" terminal to the "b" terminal, that is to say including the strict " a "and" b ".

[095] In the figures, there is shown a reference X, Y, Z corresponding to the usual orientations respectively axial (X), radial (Y) and circumferential (Z) of a tire. There is also shown a median circumferential plane M (plane perpendicular to the axis of rotation of the tire which is located midway between the two beads and passing through the middle of the crown reinforcement).

[096] There is shown in Figures 1 and 2 a tire according to the invention and designated by the general reference 10.

[097] The tire 10 is heavy vehicle type civil engineering, for example type "dumper". The tire 10 has a dimension of the type W R U, U with U≥35, preferably U≥49 and more preferably U≥57. For example, the size of the tire 10 could be 40.00 R 57 or even 59/80 R 63.

[098] In a manner known to those skilled in the art, W, designates:

when it is in the H / B form, the nominal H / B aspect ratio as defined by the ETRTO (H being the height of the section of the tire and B being the width of the section of the tire)

when it is in the form H.00 or B.00, in which H = B, H and B being as defined above.

U represents the diameter, in inches, of the seat of the rim on which the tire is intended to be mounted, R denotes the type of carcass reinforcement of the tire, here radial.

[099] The tire 10 has a vertex 12 reinforced by a crown reinforcement 14, two sidewalls 16 and two beads 18, each of these beads 18 being reinforced with a rod 20. The top 12 is radially surmounted by a strip of bearing 22 joined to the beads 18 by the flanks 16. A carcass reinforcement 24 is anchored in the two beads 18, and is here wound around the two rods 20 and comprises a reversal 26 disposed towards the outside of the tire 20 which is represented here mounted on a rim 28. The carcass reinforcement 24 is radially surmounted by the crown reinforcement 14.

The carcass reinforcement 24 comprises at least one carcass ply 30 comprising reinforcing elements, called carcass elements. Each carcass reinforcement element comprises a cable 31 according to the invention. The carcass reinforcement elements are arranged substantially parallel to each other and extend from one bead 18 to the other so as to form an angle greater than or equal to 65 °, preferably 80 ° and more preferably between 80 ° and 90 ° with the circumferential direction Z of the tire 10.

The tire 10 also comprises a sealing ply 32 made of an elastomer (commonly called inner liner) which defines the radially inner face 34 of the tire 10 and which is intended to protect the carcass ply 30 from the diffusion of the tire. air from the interior space to the tire 10.

The crown reinforcement 14 comprises, radially from the outside towards the inside of the tire 10, a protective reinforcement 36 arranged radially inside the tread 22, a working reinforcement 38 arranged radially at the inside of the protective armature 36 and an additional armature 40 arranged radially inside the armature 38. The armature 36 is thus radially interposed between the tread 22 and the armature of the armature. work 38.

The protective armature 36 comprises first and second protective plies 42, 44 comprising protective metal reinforcing elements, the first ply 42 being arranged radially inside the second ply 44. Optionally, the protective metal reinforcing elements form an angle of at least 10 °, preferably ranging from 10 ° to 35 ° and preferably from 15 ° to 30 ° with the circumferential direction Z of the tire.

The working armature 38 comprises first and second working plies 46, 48, the first ply 46 being arranged radially inside the second ply 48. Each ply 46, 48 comprises at least one metallic reinforcing element working comprising a cable 50 according to the invention. Optionally, the metal reinforcing elements of work are crossed from one working ply to another and make an angle at most equal to 60 °, preferably ranging from 15 ° to 40 ° with the circumferential direction Z of the tire .

The additional armature 40, also called limiter block, whose function is to partially recover the mechanical stresses of inflation, includes, for example and in a manner known per se, additional metal reinforcing elements, for example as described in FR 2 419 181 or FR 2 419 182 making an angle at most equal at 10 °, preferably ranging from 5 ° to 10 ° with the circumferential direction Z of the tire 10.

EXAMPLE OF CABLE ACCORDING TO THE INVENTION

There is shown in Figures 3, 4 and 5 a cable 31 according to the invention.

The cable 31 is metallic and is of the multi-strand type with two cylindrical layers of strands. Thus, it is understood that the strand layers constituting the cable 31 are two in number. The layers of strands are adjacent and concentric. The cable 31 is devoid of rubber when it is not integrated with the tire.

The cable 31 comprises an inner layer C1 of the cable 31 and an outer layer CE of the cable 31. The inner layer C1 consists of a single inner strand

Tl. The outer layer CE consists of L> 1 outer strands, that is to say several outer strands TE wound helically around the inner layer C1 in a pitch P. The cable 31 also comprises a fret F constituted a single wire wound helically around the outer layer CE. Here L = 6.

In the embodiment described, the inner and outer strands are identical. In other embodiments, the inner strand is different from each outer strand.

Each inner and outer strand has a diameter D1, DE, respectively. Preferably, the inner and outer strands are identical or not, DI = DE.

The inner strand T1 has an infinite pitch. The outer strands TE are helically wound. The pitch P of the outer strands TE is such that 30 mm <P <80 mm and preferably 40 mm <P <70 mm. Here p = 70 mm.

The hoop F is wound helically around the outer strands TE in a winding direction, here the direction Z, opposite that of the outer strands TE.

The inner strand T1 has a diameter D1 substantially equal to the diameter DE of each outer strand TE.

The outer layer CE of the cable 31 is compact. By definition, a compact layer of strands is such that there is theoretically no space for passage of the eraser between the strands of the layer.

[0116] INTERNAL TORON Tl

The inner strand T1 comprises an inner layer C1 of the strand T1 consisting of M internal thread (s) F1, an intermediate layer C2 of the strand Tl consisting of N intermediate threads F2 wound helically around the inner layer C1 in a pitch p2, and an outer layer C3 of the strand T1 consisting of P threads external F3 helically wrapped around the intermediate layer C2 in step p3. When the inner layer C1 comprises several internal threads (M> 1), the inner threads M are helically wound in a pitch p1.

Here we have N and P such that N + P> 22. On the other hand, M = 2, 3 or 4, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16. In the embodiment described, M = 4, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16, preferably M = 4, N = 7, 8, 9 or 10 and P = 14 or 15, and more preferably M = 4, N = 9 and P = 14 .

We have p1 which satisfies 4 <p1 <11 mm, preferably 5 <p1 <9 mm and here p1 = 6.5 mm. We have p2 which satisfies 6 <p2 <20 mm, preferably 8 <p2 <18 mm and here p2 = 12 mm. We have p3 which satisfies 10 <p3 <30 mm, preferably 14 <p3 <22 mm and here p3 = 16 mm.

Each internal wire F1, intermediate F2 and external F3 of the inner strand Tl respectively has a diameter d1, d2 and d3. Each wire has a breaking strength, denoted Rm, such that 2500 <Rm <3100 MPa. The steel of these threads is said to be of grade NT ("Normal Tensile"). Each diameter d1, d2, d3 of each wire respectively of each inner layer C1, intermediate C2 and outer C3 of the inner strand T1 satisfies 0.15 <d1, d2, d3 <0.5 mm, preferably 0.18 <d1, d2, d3 <0.30 mm, more preferably 0.20 <d1, d2, d3 <0.28 mm. Other steel grades leading to yarns having a higher tensile strength than NT grade yarns can be used, for example HT (High Tensile) or Super High Tensile (SHT) yarns. ).

Preferably, here d1 = d2 = d3 = 0.26 mm. Alternatively, one could have d1> d2.

In each intermediate layer C2 and outer C3, on a section of the cable perpendicular to the main axis of the cable, at least two adjacent son are respectively separated by a channel P2, P3 of the gum. Two adjacent wires of the same layer C2, C3 are separated, on average on each layer C2, C3, by an inter-wire distance D2, D3 defined as the smallest distance separating these two adjacent wires. D2 is greater than or equal to 25 μηη. Advantageously, D2 is greater than or equal to 30 μηι, preferably 35 μηι. D3 is greater than or equal to 25 μηι. Advantageously, D3 is greater than or equal to 30 μηι, preferably 35 μηη and more preferably 40 μηη. In addition, each inter-son distance D2, D3 is less than or equal to 100 μηι, preferably 60 μηι.

The inter-son distance D2 between the intermediate M son F2 is here equal to 38.2 μηι. The inter-son distance D3 between the N external wires F3 is here equal to 44.2 μηι. Each intermediate layer C2 and outer C3 of the inner strand T1 is non-compact and unsaturated.

Here we have D3> D2 and the ratio D2 / D3 satisfying 0.5 <D2 / D3 <1, 5, preferably 0.7 <D2 / D3 <1, 3, more preferably 0.8 <D2 / D3 <1, 2. In this case, D2 / D3 = 0.86.

EXTERNAL TORONS TE

Each outer strand TE comprises an inner layer C1 'of the strand TE consisting of M' internal thread (s) F1 ', an intermediate layer C2' of the strand TE consisting of N 'intermediate threads F2' wound helically around the inner layer C1 'in a pitch p2', and an outer layer C3 'of the strand TE consisting of P' external wires F3 'helically wound around the intermediate layer C2' in a pitch p3 '. When the inner layer C1 'comprises several internal wires (M'> 1), the inner threads M 'are helically wound in a pitch p1'.

Here we have N 'and P' such that N '+ P'> 22. On the other hand, M '= 2, 3 or 4, N' = 7, 8, 9 or 10 and P-13, 14, 15 or 16. In the embodiment described, M '= 4, N' = 7, 8, 9 or 10 and P '= 13, 14, 15 or 16, preferably M' = 4, N '= 7, 8, 9 or 10 and P' = 14 or 15, and more preferably M '= 4, N '= 9 and P-14.

For each outer strand TE, considered unwound from around the inner layer C1, p1 'which verifies 4 <p1' <11 mm, preferably 5 <p1 '<9 mm and here p1' = 6.5 mm. We have p2 'which satisfies 6 <p2' <20 mm, preferably 8 <p2 '<18 mm and here p2' = 12 mm. P3 'which verifies 10 <p3' <30 mm, preferably 14 <p3 '<22 mm and here p3' = 16 mm.

Each internal thread F1 ', intermediate F2' and external F3 'of each outer strand TE respectively has a diameter d1', d2 'and d3'. Each wire has a breaking strength, denoted Rm, such that 2500 <Rm <3100 MPa. The steel of these threads is said to be of grade NT ("Normal Tensile"). Each diameter d1 ', d2', d3 'of each wire respectively of each inner layer C1', intermediate C2 'and outer C3' of each outer strand TE satisfies 0.15 <d1 ', d2', d3 '<0.5 mm, preferably 0.18 <d1 \ d2 ', d3' <0.30 mm, more preferably 0.20 <d1 ', d2', d3 '<0.28 mm.

[0130] Preferably, d1 '= d2' = d3 '= 0.26 mm is used here. Alternatively, one could have d1 '> d2'.

In a similar way to the inner strand T1, two adjacent wires of the same layer C2 ', C3' are separated, on average on each layer C2 ', C3', by an interfering distance D2 ', D3' defined as the smaller distance separating these two adjacent wires. D2 'is greater than or equal to 25 μηι. Advantageously, D2 'is greater than or equal to 30 μηι, preferably 35 μηι. D3 'is greater than or equal to 25 μηι. Advantageously, D3 'is greater than or equal to 30 μηι, preferably 35 μηη and more preferably 40 μηι. In addition, each inter-wire distance D2 ', D3' is less than or equal to 100 μηι, preferably 60 μηι.

The inter-son distance D2 'between the intermediate son M F2' is here equal to 38.2 μηη. The inter-wire distance D3 'between the N external wires F3' is here equal to 44.2 μηη. Each intermediate layer C2 and outer C3 of the inner strand T1 is non-compact and unsaturated.

Here we have D3 '> D2' and the ratio D27D3 'satisfying 0.5 <D27D3' <1, 5, preferably 0.7 <D27D3 '<1, 3, more preferably 0.8 <D27D3' < 1, 2. In this case, D27D3 '= 0.86.

In the example described, the external wires F3 'of the outer layer C3' of each outer strand TE are wound in a winding direction identical to that of the outer wires F3 of the outer layer C3 of each inner strand T1. .

In addition, the outer strands TE are wound around the inner strand T1 in a winding direction opposite to that of the wires F3 'of the outer layer C3' of each outer strand TE. Thus, the outer strands TE are wound around the inner strand T1 in the direction S and the wires F3 'of the outer layer C3' of each outer strand TE are wound in the direction Z.

Still in the example described, the wires F1, F2 respectively of the inner and intermediate layers C1, C2 of each inner strand T1 are wound in identical winding directions, here in the direction Z. Similarly, the son F1 ', F2' respectively of the inner and intermediate layers C1 ', C2' of each outer strand TE are wound in identical winding directions, here in the direction Z.

The wires F3, F3 'respectively of the outer layers C3, C3' of each inner strand T1 and outer TE are wound in the same winding directions as the wires F2, F2 'respectively of the intermediate layers C2, C2' each inner strand T1 and outer TE, here in the direction Z.

The cable according to the invention is manufactured by a process comprising steps that are well known to those skilled in the art. Thus, it is recalled that there are two possible techniques for assembling wires or metal strands:

or by wiring: in such a case, the son or strands do not undergo torsion around their own axis, due to a synchronous rotation before and after the point of assembly;

- Or by twisting: in such a case, the son or strands undergo both a collective twist and an individual twist around their own axis, which generates a pair of detorsions on each of the wires or strands.

The cable 31 is incorporated by calendering with composite fabrics formed of a known composition based on natural rubber and carbon black as reinforcing filler, conventionally used for the manufacture of radial tire crown reinforcement. This composition essentially comprises, in addition to the elastomer and the reinforcing filler (carbon black), an antioxidant, stearic acid, an extension oil, cobalt naphthenate as adhesion promoter, finally a vulcanization system (sulfur, accelerator, ZnO).

Composite fabrics reinforced by these cables comprise a rubber matrix formed of two thin layers of rubber which are superimposed on both sides of the cables and which respectively have a thickness of between 1 and 4 mm inclusive. The calender pitch (no laying of the cables in the rubber fabric) is between 4 mm and 8 mm inclusive.

These composite fabrics are then used as a web in the tire, in particular as a web in the carcass reinforcement during the manufacturing process of the tire, the steps of which are otherwise known to those skilled in the art.

[0142] Measurements and comparative tests

[0143] A control cable T1 and a cable 11 according to the invention were compared.

The cable 11, is a cable 189.26 FR according to the invention of structure [(4 + 9 + 14) x0.26) + 6x (4 + 9 + 14) x0.26)] + 0.26 and whose wires are of grade NT. The cable 11 is the cable 31 previously described and shown in FIG. 3 and photographed in FIG.

The control cable T1, photographed in FIG. 7, is a cable 189.23 FR of structure [(3 + 9 + 15) x0.23 + 6x (3 + 9 + 15) x0.23] +0.26 and whose sons are of grade NT.

[0146] Dynamometric measurements

The measure of force at break noted Fm (maximum load in N) is performed in tension according to the ISO 6892-1 standard of 2009. Table 1 below shows the results obtained of force at break Fm.

[0148] Facies note

This test makes it possible to note the penetrability of the tested cable in order to evaluate the adhesion of the latter in a tire. In this test, cables from manufacturing and unaged are used. The raw cables are previously coated from the outside with a so-called coating gum. For this, a series of 5 cables arranged in parallel (inter-cable distance: 20 mm) is placed between two layers or "skims" (two rectangles of 80 x 200 mm) of a diene rubber composition in the green state, each skim having a thickness of 5 mm; the whole is then locked in a mold, each of the cables being kept under a sufficient tension (for example 3 daN) to ensure its straightness during the establishment in the mold, using clamping modules; then the vulcanization (baking) is carried out for about 10 to 12 hours at a temperature of about 120 ° C and a pressure of 15 bar (rectangular piston 80 x 200 mm). After that, the assembly is demolded and 5 specimens of cables thus coated, in the form of parallelepipeds of dimensions 7x7x60 mm, are cut for observation under the microscope (magnification 40 for the cable and magnification 120 for each strand).

A conventional rubber diene rubber composition based on natural rubber (peptized) and carbon black N330 (65 phr), comprising the following usual additives: sulfur (7 phr), is used as a coating rubber. ), sulfenamide accelerator (1 phr), ZnO (8 phr), stearic acid (0.7 phr), antioxidant (1.5 phr), cobalt naphthenate (1.5 phr) (phr parts per hundred parts) elastomer); the E10 module of the coating gum is approximately 10 MPa.

When observed under the microscope, the following notes are given to each outer strand:

0: the outer layer of the outer strand has a capillary opening on the adhesive interface between the cable and the adjacent mixture.

1: the intermediate layer of the outer strand has a capillary opening on the outer layer of the outer strand. The outer layer is isolated.

- 2: the intermediate layer has a capillary does not open on the outer layer. The capillaries of the outer strand are located at the periphery of the central strand opposite the adhesive interface between the cable and the adjacent mixture.

3: the intermediate layer of the outer strand does not have a capillary. The capillary is only inside the inner layer.

Then, we sum the scores obtained for each strand and for each cable tested, a total of 25 notes. The sum is reported at the maximum possible score of 75.

The results of the tests carried out on the cable 11 according to the invention and the control cable T1 are summarized in Table 1 below.

Table 1

It is noted that the cable 11 according to the invention has both an improved breaking force and an adhesion that can be considered as improved due to the lower presence of capillaries at the adhesive interface than for the T1 indicator cable as shown by the presence of many capillaries in Figure 7 (T1 control cable) and the absence of these capillaries in Figure 6 (cable of the invention 11).

Of course, the invention is not limited to the previously described embodiment.

For example, some son could be non-circular section, for example plastically deformed, including a substantially oval section or polygonal, for example triangular, square or rectangular.

The son, of circular section or not, for example a corrugated wire, may be twisted, twisted helical or zig-zag. In such cases, it must of course be understood that the diameter of the wire represents the diameter of the cylinder of imaginary revolution which surrounds the wire (space diameter), and no longer the diameter (or any other transverse size, if its section is not circular) of the core wire itself.

For reasons of industrial feasibility, cost and overall performance, it is preferred to implement the invention with linear son, that is to say right, and conventional circular cross section.

It is also possible to combine the characteristics of the different embodiments described or envisaged above provided that they are compatible with each other.

It will thus be possible to envisage embodiments in which each inner strand is such that M = 2, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16, preferably M = 2, N = 7, 8 or 9 and P = 14, and more preferably M = 2, N = 9 and P = 14 or in which each inner strand is such that M = 3, N = 7, 8, 9 or 10 and P = 13, 14, 15 or 16, preferably M = 3, N = 8 or 9 and P = 14 or 15, and more preferably M = 3, N = 9 and P = 14.

Embodiments may also be envisaged in which each outer strand is such that M -2, N '= 7, 8, 9 or 10 and P -13, 14, 15 or 16, preferably M -2, N -7, 8 or 9 and P '= 14, and more preferably M -2, N -9 and P-14 or in which each outer strand is such that M -3, N -7, 8, 9 or 10 and P '= 13, 14, 15 or 16, preferably M' = 3, N '= 8 or 9 and P' = 14 or 15, and more preferably M -3, N-9 and P-14.

Finally, it is possible to envisage embodiments in which each inner and / or outer strand is in two layers, that is to say that the outer layer is wound directly in contact with the inner layer of each inner strand. and / or external. Each inner and / or outer strand is devoid of intermediate layer.

Claims

1. Multi-strand cable (31) with two strand layers, characterized in that it comprises:

an inner layer (Cl) of the cable (31) consisting of a single inner strand (Tl),

an outer layer (CE) of the cable (31) compact and consisting of L> 1 outer strands (TE),

each inner and outer strand (T1, TE) comprising:

an internal and external strand inner layer (C1, C1 ') (T1, TE) respectively consisting of M and M' internal thread (s) (F1, F1 '),

an outer layer (C3, C3 ') of the inner and outer strand (Tl, TE) respectively consisting of P and P' external wires (F3, F3 ') helically wound around each inner layer (C1, C1') respectively internal and external strand (Tl, TE),

in which the inter-wire distance D3 'of the wires of the outer layer (C3') of each outer strand (TE) is greater than or equal to 25 μητ

2. Cable (31) according to the preceding claim, wherein the interfil distance D'3 is greater than or equal to 30 μηι, preferably 35 μηη and more preferably 40 μηη.

3. Cable (31) according to any one of the preceding claims, wherein the diameter Dl of each inner strand (T1) is substantially equal to the diameter DE of each outer strand (TE).

4. Cable (31) according to any one of the preceding claims, wherein L = 6.

5. Cable (31) according to any one of the preceding claims, wherein each inner and outer strand (Tl, TE) comprises an intermediate layer (C2, C2 ') of the inner and outer strand (Tl, TE) respectively constituted of N and N 'intermediate wires (F2, F2') helically wound around each inner layer (C1, C1 ') respectively of the inner and outer strand (Tl, TE), the outer layer (C3, C3') of the strand internal and external (Tl, TE) being wound helically around each intermediate layer (C2, C2 ') respectively of the inner and outer strand (ΤΙ, ΤΕ).

6. Cable (31) according to claim 5, wherein Μ = Μ ', N = N' and P = P '.

The cable (31) according to claim 5 or 6, wherein the interfering distance D2 'of the wires of the intermediate layer (C2') of each outer strand (TE) is greater than or equal to 25 μηι, preferably 30 μηι and more preferably 35 μηι.

8. Cable (31) according to the preceding claim, wherein the ratio D27D3 'verifies 0.5 <D27D3' <1, 5, preferably 0.7 <D27D3 '<1, 3, more preferably 0.8 <D27D3' <1, 2.

9. Cable (31) according to any one of claims 5 to 8, wherein N 'and P' are such that N '+ P'> 22.

10. Cable (31) according to any one of claims 5 to 9, wherein M '= 2, 3 or 4, N' = 7, 8, 9 or 10 and P '= 13, 14, 15 or 16.

1 1. Cable (31) according to the preceding claim, in which M '= 4, N' = 7,

8, 9 or 10 and P '= 13, 14, 15 or 16, preferably M' = 4, N '= 7, 8, 9 or 10 and P' = 14 or 15, and more preferably M '= 4, N '= 9 and P-14.

12. Cable (31) according to any one of claims 5 to 1 1, wherein each diameter d1 ', d2', d3 'of each wire respectively of each inner layer (C1'), intermediate (C2 ') and external (C3 ') of each outer strand (TE) satisfies 0,15 <d1', d2 ', d3' <0,5 mm, preferably 0,18 <d1 ', d2', d3 '<0,30 mm, more preferably 0.20 <d1 ', d2', d3 '<0.28 mm.

13. Cable (31) according to any one of claims 5 to 12, wherein each diameter d2 ', d3' of each wire (F2 ', F3') respectively of each intermediate layer (C2 ') and external (C3' ) of each outer strand (TE) satisfies d2 '= d3'.

14. Cable (31) according to any one of claims 5 to 13, wherein each diameter d1 ', d2' of each wire (F1 \ F2 ') respectively of each inner layer (C1') and intermediate (C2 ') each outer strand (TE) checks d1 '= d2'.

15. Pneumatic tire (10), characterized in that it comprises at least one reinforcing element comprising a cable (31) according to any one of claims 1 to 14.

16. Pneumatic tire (10) according to the preceding claim, comprising a carcass reinforcement (24) anchored in two beads (18), said carcass reinforcement (24) comprising at least one reinforcement element, called carcass, comprising a cable ( 31) according to any one of claims 1 to 14.

17. A tire (10) according to the preceding claim, wherein the carcass reinforcement (24) comprises at least one carcass ply (30) comprising reinforcement elements, said carcass, the carcass reinforcement elements forming an angle greater than or equal to 65 °, preferably greater than 80 ° preferably between 80 ° and 90 ° with respect to the circumferential direction (Z) of the tire (10).

18. Pneumatic tire (10) according to any one of claims 15 to 17, having a dimension of type W R U with U≥35, preferably U≥49 and more preferably U≥57.