Double-layer multi-strand rope with improved permeability

Description

[0001] The invention relates to multi-strand cables which can be used in particular for reinforcing tires, particularly tires for heavy industrial vehicles.

[0002] A radial carcass reinforcement tire comprises a tread, two inextensible beads, two sidewalls connecting the beads to the tread and a belt, or crown reinforcement, arranged circumferentially between the carcass reinforcement and the tread. The carcass reinforcement and the crown reinforcement comprise several plies of elastomeric composition, possibly reinforced by reinforcing elements such as cables or monofilaments, of metallic or textile type.

[0003] The carcass reinforcement is anchored in each bead and radially surmounted by the crown reinforcement. The carcass reinforcement comprises a carcass ply comprising metallic carcass reinforcing wire elements. Each metallic carcass reinforcing wire element makes an angle of between 80° and 90° with the circumferential direction of the tire.

[0004] The crown reinforcement generally comprises at least two superimposed crown plies, sometimes called working plies or crossed plies, the reinforcing elements of which, generally metallic, are arranged practically parallel to each other within a ply, but crossed from one ply to the other, that is to say inclined, symmetrically or not, with respect to the median circumferential plane, at an angle which is generally between 10° and 45°. The working plies generally comprise reinforcing elements having a very low elongation so as to ensure their function of guiding the tire.

[0005] The crown reinforcement may also comprise various other auxiliary plies or layers of elastomeric composition, of variable widths depending on the case, comprising or not reinforcing elements. Examples include so-called protective plies intended to protect the rest of the belt from external attacks, perforations, or so-called hoop plies comprising reinforcing elements oriented substantially in the circumferential direction (so-called zero-degree plies), whether radially external or internal relative to the working plies. The protective plies generally comprise reinforcing elements having a high elongation so as to deform under the effect of a stress exerted by an indenter, for example a rock.

[0006] Known from the prior art is a reinforcing element for the plies described above comprising a two-layer multi-strand metal cable as disclosed in the examples of WO2011064065, WO2016202622 and WO2009048054. These cables comprise 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.

[0007] Each inner and outer strand comprises an inner layer of the strand consisting of two, three or four inner wires, an intermediate layer consisting of seven to nine intermediate wires and an outer layer consisting of twelve to fifteen outer wires. The intermediate and outer layers of the inner strand are wound in the Z direction around the inner and intermediate layers of the inner strand respectively. The intermediate and outer layers of each outer strand are wound in the Z direction around the inner and intermediate layers of each outer strand respectively. The outer strands are wound helically around the inner strand in one direction of winding of the rope, this being the S direction.

[0008] Also known from the prior art are multi-strand cables as disclosed in WO2014090996, WO2011144472, JP2008260409, JP2006291419 and WO2015193099.

[0009] A tire for a heavy industrial vehicle, particularly a civil engineering vehicle, is subject to numerous attacks. Indeed, the rolling of this type of tire is usually done on uneven surfaces, sometimes leading to perforations in the tread. These perforations allow the entry of corrosive agents, for example air and water, which oxidize the metal reinforcing elements of the various reinforcements, particularly the crown plies, and considerably reduce the tire's lifespan.

[0010] One solution to increase the tire's lifespan is to combat the spread of these corrosive agents. It is therefore possible to cover each inner and intermediate layer with an elastomeric composition during the manufacture of the cable. During this process, the elastomeric composition penetrates the capillaries present between each layer of each strand and thus prevents the spread of corrosive agents. Such cables, generally called in situ rubberized cables, are well known in the state of the art.

[0011] Another solution to increase the tire's lifespan is to increase the breaking force of the cord. Generally, breaking force is increased by increasing the diameter of the cords constituting the cord and / or the number of cords and / or the unit strength of each cord. However, increasing the cord diameter further, for example beyond 0.50 mm, necessarily leads to a decrease in the flexibility of the cord, which is not desirable. Increasing the number of cords most often leads to a decrease in the penetrability of the strands due to the elastomer composition. Finally, increasing the unit strength of each cord requires significant investment in cord manufacturing facilities.

[0012] The aim of the invention is to provide a cable having better penetrability of each internal strand due to the elastomer composition compared to the cable of the prior art, thus making it possible to reduce the entry and propagation of corrosive agents into and along the cable. CABLE ACCORDING TO THE INVENTION

[0013] For this purpose, the invention relates to a two-layer multi-strand cable according to claim 1.

[0014] It is recalled that, as is known, the pitch of a strand represents the length of this strand, measured parallel to the axis of the cable, at the end of which the strand having this pitch makes a complete turn around said axis of the cable. Similarly, the pitch of a wire represents the length of this wire, measured parallel to the axis of the strand in which it is located, at the end of which the wire having this pitch makes a complete turn around said axis of the strand.

[0015] The winding direction of a layer of strands or wires means the direction formed by the strands or wires relative to the axis of the cable or strand. The winding direction is commonly designated by the letter either Z or S.

[0016] The pitches, winding directions and diameters of wires and strands are determined in accordance with ASTM D2969-04 of 2014.

[0017] According to the invention, the outer layer of the cable is desaturated.

[0018] By definition, a desaturated layer of strands is such that there is sufficient space between the strands to allow the passage of an elastomer composition. A desaturated outer layer of strands means that the outer strands do not touch each other and there is sufficient space between two adjacent outer strands to allow the passage of an elastomer composition to the inner strands. In contrast, a saturated layer of strands is such that there is not sufficient space between the strands of the layer to allow the passage of an elastomer composition, for example because the strands of the layer touch each other in pairs.

[0019] According to the invention, the inter-strand distance of the outer layer of outer strands defined, on a section of the cable perpendicular to the main axis of the cable, as the shortest distance which separates, on average, the circular envelopes in which two adjacent outer strands are inscribed, is greater than or equal to 30 µm.

[0020] Preferably, the average inter-strand distance E separating two adjacent external strands is greater than or equal to 200 µm.

[0021] By "at least two layers" is meant that each outer strand may be, in some embodiments, two-layered, i.e., each outer strand comprises only two layers but does not comprise only one or three; and in other embodiments, each outer strand may be three-layered, i.e., each outer strand comprises only three layers but does not comprise only two or four.

[0022] In the invention, the cable is two-layer stranded, that is, it comprises an assembly consisting of two layers of strands, no more and no less, that is, the assembly has two layers of strands, not one, not three, but only two. The outer layer of the cable is wound around the inner layer of the cable in contact with the inner layer of the cable.

[0023] The cable according to the invention has improved penetrability compared to a cable whose ratio (p3-p2) / p3 is outside the range of ratios according to the invention. The inventors behind the invention hypothesize that this ratio makes it possible to obtain relatively large radial passage windows for the elastomer composition within each inner strand. The radial passage windows are defined as the intersection between, on the one hand, the space projected onto a plane parallel to the main axis of the cable between two adjacent wires of the outer layer of each inner strand and, on the other hand, the space projected onto a plane parallel to the main axis of the cable between two adjacent wires of the intermediate layer of each inner strand. Such a radial passage window is illustrated in Figure 25.

[0024] In addition, thanks to the desaturation of the outer layer of the cable, the cable according to the invention has spaces between the outer strands allowing the passage of the elastomer composition. In the prior art, cables are known having a relatively high breaking force due to the saturation of the outer layer of the cable (the outer strands are in contact with each other in pairs) which then forms an arch taking up the tensile forces exerted on the cable. In the cable according to the invention, although the arch is broken around the inner layer, the high penetrability of each inner strand made possible by the ratio (p3-p2) / p3 and the desaturation of the outer layer of the cable allows the elastomer composition to penetrate on the one hand, between the outer strands and, on the other hand, between the outer strands and each inner strand.Thus, the arch is at least partially restored and therefore the loss of breaking force of the cable is limited while ensuring its excellent penetrability. In addition, this characteristic allows the elastomer composition to infiltrate between the outer layers of the internal and external strands so as to create a mattress of elastomer composition absorbing at least partially the radial component of the force between the internal and external strands.

[0025] In a cable of the prior art comprising an inner layer of the cable consisting of a single inner strand, a significant desaturation of the outer layer of the cable for the purpose of promoting the penetrability of the cable results in a significant loss of metal mass and therefore a relatively significant drop in the breaking force of the cable. In the cable of the invention, a significant desaturation of the outer layer of the cable for the purpose of promoting the penetrability of the cable results, due to the presence of K inner strands, in a less significant drop in the metal mass and therefore a controlled drop in the breaking force, unlike the cables of the prior art in which the contribution of each outer strand to the breaking force is greater than in the cables according to the invention.

[0026] By the invention and the relationship between p2 and p3 and by the relationship between p1, p2 and the directions of the inner and intermediate layers of each inner strand, each inner strand is cylindrically layered. Very advantageously, each outer strand is cylindrically layered whether this outer strand is two- or three-layered. A cylindrically layered strand is very highly penetrable unlike a compactly layered strand in which the pitches of all the layers are equal and the winding directions of all the layers are identical and has much lower penetrability.

[0027] Optionally and preferably, in one embodiment, the cable is devoid of any polymeric composition, in particular the cable is devoid of a sheath of any polymeric composition covering each internal strand. In another embodiment, the cable is devoid of any elastomeric composition, in particular the cable is devoid of a sheath of any elastomeric composition covering each internal strand.

[0028] Advantageously, the cable is metallic. By definition, a metallic cable is meant a cable formed of wires consisting mainly (i.e., more than 50% of these wires) or entirely (100% of the wires) of a metallic material. Such a metallic cable is preferably implemented with a steel cable, more preferably pearlitic (or ferrito-pearlitic) carbon steel, hereinafter referred to as "carbon steel", or even stainless steel (by definition, steel comprising at least 11% chromium and at least 50% iron). But it is of course possible to use other steels or other alloys.

[0029] When a carbon steel is advantageously used, its carbon content (% by weight of steel) is preferably between 0.4% and 1.2%, in particular between 0.5% and 1.1%; these contents represent a good compromise between the mechanical properties required for the tire and the feasibility of the wires.

[0030] The metal or steel used, whether in particular carbon steel or stainless steel, may itself be coated with a metallic layer improving, for example, the processing properties of the metal cable and / or its constituent elements, or the usage properties of the cable and / or the tire themselves, such as adhesion properties, corrosion resistance or even resistance to aging. According to a preferred embodiment, the steel used is covered with a layer of brass (Zn-Cu alloy) or zinc.

[0031] Preferably, the wires of the same layer of a predetermined strand (inner or outer) all have substantially the same diameter. Advantageously, the outer strands all have substantially the same diameter. By "substantially the same diameter" is meant that the wires or strands have the same diameter within industrial tolerances.

[0032] Advantageously, each wire of each strand has a diameter ranging from 0.15 mm to 0.60 mm, preferably from 0.20 mm to 0.50 mm, more preferably from 0.22 mm to 0.40 mm and even more preferably from 0.24 mm to 0.35 mm.

[0033] By polymer composition or polymeric composition is meant that the composition comprises at least one polymer. Preferably, such a polymer may be a thermoplastic, for example a polyester or a polyamide, a thermosetting polymer, an elastomer, for example natural rubber, a thermoplastic elastomer or a mixture of these polymers.

[0034] By elastomer composition or elastomeric composition, it is meant that the composition comprises at least one elastomer or rubber (the two terms being synonymous) and at least one other component. Preferably, the elastomer composition also comprises a vulcanization system, a filler. More preferably, the elastomer is diene.

[0035] Advantageously: 0.38 ≤ (p3-p2) / p3 in the case where Q=2, 0.38 ≤ (p3-p2) / p3 in the case where Q=3.

[0036] The higher the ratio (p3-p2) / p3, in other words the greater the difference between p3 and p2, the better the architectural stability of each internal strand. In fact, the more the intermediate and external layers of each internal strand have different pitches, the more the intermediate and external wires are crossed in relation to each other (the contacts between the intermediate and external wires are then relatively punctual), the better the external wires will mechanically hold the intermediate wires and the better the penetrability of each internal strand, the wires of the intermediate and external layers of which will then be regularly distributed within each intermediate and external layer.This mechanical strength makes it possible to prevent, on the one hand, during the manufacture of the cable, all the wires of the intermediate layer from grouping together in contact with each other under the effect of the mechanical forces exerted by the assembly tools and, on the other hand, during the manufacture of a ply comprising the cable or of the tire comprising the cable, all the wires of the intermediate layer from grouping together in contact with each other under the effect of the pressure of the elastomer composition penetrating the cable.

[0037] Furthermore, for a given pitch p3, by increasing the ratio (p3-p2) / p3, the inter-wire distance of the intermediate layer of each internal strand is reduced. A person skilled in the art would have expected to observe a reduction in the penetrability of each internal strand. However, completely unexpectedly, as shown by the comparative tests described below, by increasing the ratio (p3-p2) / p3, the inter-wire distance of the intermediate layer of each internal strand is certainly reduced but the size of the radial passage windows of the elastomer composition is increased so that the penetrability of each internal strand is significantly improved.

[0038] Advantageously: (p3-p2) / p3 ≤ 0.42 and preferably (p3-p2) / p3 ≤ 0.40 in the case where Q=2, (p3-p2) / p3 ≤ 0.40 in the case where Q=3, (p3-p2) / p3 ≤ 0.40 and preferably (p3-p2) / p3 ≤ 0.38 in the case where Q=4. Below these values, the dimension of the radial passage windows of the elastomer composition is maximum and allows the penetrability of each internal strand to be optimized.

[0039] Advantageously, the pitch p1 is such that 3 mm ≤ p1 ≤ 16 mm, preferably 4 mm ≤ p1 ≤ 13 mm and more preferably 5 mm ≤ p1 ≤ 10 mm.

[0040] Advantageously, the pitch p2 is such that 8 mm ≤ p2 ≤ 20 mm, preferably 9 mm ≤ p2 ≤ 18 mm and more preferably 10 mm ≤ p2 ≤ 16 mm.

[0041] Advantageously, the pitch p3 is such that 10 mm ≤ p3 ≤ 40 mm, preferably 12 mm ≤ p3 ≤ 30 mm and more preferably 15 mm ≤ p3 ≤ 25 mm.

[0042] Steps p1, p2 and p3 in these preferred ranges make it possible to obtain a cable with mechanical properties compatible with pneumatic use, at a relatively low cost and linear mass of the cable.

[0043] Advantageously, K=2, 3 or 4, preferably K=3 or 4.

[0044] In one embodiment, L is equal to 7, 8, 9 or 10, preferably L=8, 9 or 10 and more preferably L=8 or 9.

[0045] In a first variant, K=2 and L=7 or 8.

[0046] In a second variant, K=3 and L=7, 8 or 9, preferably K=3, L=8 or 9. In the case where L=8, the desaturation of the outer layer of the cable is favored and therefore the penetrability of the cable between the outer strands. In the case where L=9, the number of outer strands is maximized and therefore the breaking strength of the cable.

[0047] In a third variant, K=4 and L=7, 8, 9 or 10, preferably K=4, L=9 or 10.

[0048] In these embodiments, in particular those where K=3 or 4, there is a risk of seeing a very strong propagation of the corrosive agents between the K=3 or 4 internal strands which delimit a central capillary very favorable to their propagation along the cable, when the cable is insufficiently penetrated. This drawback can be overcome by making the cable penetrable by the elastomer composition which then prevents the corrosive agents from accessing the central capillary, and in the best case where the central capillary is itself penetrated, the propagation of these corrosive agents along the cable.

[0049] As already explained above, the cables according to the invention having an architecture in which K>1, the most severe transverse forces exerted in the cable when it is tensioned are the transverse forces exerted between the internal strands, unlike a cable in which K=1 and in which the most severe transverse forces are the transverse forces exerted by the external strands on the internal strands. In the state of the art, cables are known having an architecture in which K>1 and comprising a number of external strands such that the external layer of the cable is saturated so as to maximize the breaking force by adding a maximum number of external strands. Here, thanks to the desaturation of the external layer of the cable, the cable has, on the one hand, spaces between the external strands allowing the passage of the elastomer composition and therefore making the cable less sensitive to corrosion.On the other hand, although the number of external strands is reduced, the desaturation of the external layer of the cable allows the elastomer composition to penetrate, on the one hand, between the external strands and, on the other hand, between the internal strands so as to form a cushion of elastomer composition absorbing at least partially the transverse forces exerted between the internal strands. Thus, compared to a similar cable having a saturated external layer of the cable, a better compromise between breaking strength and corrosion resistance is obtained.

[0050] In one embodiment promoting cable penetrability, the outer layer of the cable is completely unsaturated.

[0051] By definition, a completely unsaturated layer of strands is, as opposed to an incompletely unsaturated layer, such that there is sufficient space in this layer to add at least one (X+1) th< strand of the same diameter as the X strands of the layer, several strands then being able to be in contact with each other or not. In this case, there is sufficient space in the outer layer of the cable to add at least one (L+1) th< strand of the same diameter as the L outer strands of the outer layer of the cable.

[0052] Thus, advantageously, the sum SIE of the interstrand distances E of the outer layer of the cable is such that SIE ≥ DE. The sum SIE is the sum of the interstrand distances E separating each pair of adjacent strands of the layer. The interstrand distance of a layer is defined, on a section of the cable perpendicular to the main axis of the cable, as the shortest distance which separates, on average, two adjacent strands of the layer. Thus, the interstrand distance E is calculated by dividing the sum SIE by the number of spaces separating the strands of the layer.

[0053] In another embodiment favoring the compromise between penetrability and breaking strength, the outer layer of the cable is incompletely unsaturated.

[0054] An incompletely unsaturated layer of strands is such that there is not enough room in this layer to add at least one (X+1) th< strand of the same diameter as the X strands of the layer. In this case, there is not enough room in the outer layer to add at least one (L+1) th< outer strand of the same diameter as the L outer strands of the outer layer of the cable.

[0055] By definition, the diameter of an inner strand DI is the diameter of the smallest circle in which the inner strand is circumscribed. The diameter of an outer strand DE is the diameter of the smallest circle in which the outer strand is circumscribed.

[0056] In a preferred embodiment, the inner layer of the cable is helically wound at a non-zero pitch pi and the outer layer of the cable is helically wound around the inner layer of the cable at a non-zero pitch pe.

[0057] In a particularly advantageous embodiment for the penetrability of the cable, the inner layer of the cable is wound in a helix in a direction of the inner layer of the cable with a pitch pi, the outer layer of the cable is wound in a helix in a direction of the outer layer of the cable with a pitch pe, the cable satisfies one and / or the other of the following characteristics: the direction of inner layer of cable is different from the direction of outer layer of cable, pi is different from pe.

[0058] In this embodiment, the cable has a cylindrical layered structure (as opposed to a compact structure), promoting the penetrability of the cable.

[0059] In another embodiment, the inner layer of the cable is wound in a helix in a direction of the inner layer of the cable with a pitch pi, the outer layer of the cable is wound in a helix in a direction of the outer layer of the cable with a pitch pe, the cable meets the following characteristics: the direction of the inner layer of the cable is the same as the direction of the outer layer of the cable, pi is equal to pe.

[0060] In this embodiment, despite the compact structure of the cable which is difficult to penetrate, the high penetrability of the internal strands nevertheless makes it possible to obtain a satisfactorily penetrated cable.

[0061] Optionally, each outer wire of each inner strand has a diameter d3 greater than or equal to the diameter d3' of each outer wire of each outer strand, preferably each outer wire of each inner strand has a diameter d3 greater than the diameter d3' of each outer wire of each outer strand. Preferably, thanks to the characteristic d3>d3', each outer wire of each inner strand can withstand the radial component of the force exerted by the outer strands on each inner strand during traction of the cable. This characteristic d3>d3' makes it possible to restore, or even improve, the breaking force of the cable compared to a cable comprising an arch formed by the outer strands or compared to a cable in which d3≤d3'. Preferably, 1 < d3 / d3' ≤ 2, more preferably 1 < d3 / d3' ≤ 1.5 and even more preferably 1 < d3 / d3' ≤ 1.25 or 1.25 < d3 / d3' ≤ 1.5.

[0062] In an advantageous embodiment, the outer layer of the cable is wound around the inner layer of the cable in a winding direction of the outer layer of the cable and each outer layer of each inner and outer strand is wound respectively around the intermediate and inner layer respectively of each inner and outer strand in the same winding direction opposite to the winding direction of the cable. In this embodiment, the winding direction of the cable opposite to the winding directions of each outer layer of each inner and outer strand allows better penetrability of the cable, in particular between the outer strands.The inventors hypothesize that thanks to these winding directions, the outer wires of the outer strands cross the outer wires of each inner strand, forming a relatively point-like contact zone, unlike cables in which the winding direction of the cable would be identical to the winding directions of the outer layers of each inner and outer strand and in which the outer wires of the outer strands would cross the outer wires of the inner strand, forming a less point-like and more linear contact zone, preventing the passage of the elastomer composition to the inner layer. Internal strand of the cable according to the invention

[0063] In embodiments, M=7, 8, 9 or 10, N=12, 13, 14 or 15.

[0064] In a first variant, Q=2, M=7 or 8 and N=12 or 13. In the case where M=7 and / or N=12, the desaturation of the intermediate or external layer of each internal strand is favored and therefore the penetrability of each internal strand. In the case where M=8 and / or N=13, the number of intermediate or external wires is maximized and therefore the breaking strength of the cable.

[0065] In a second variant, Q=3, M=8 or 9 and N=13 or 14. In the case where M=8 and / or N=13, the desaturation of the intermediate or external layer of each internal strand is favored and therefore the penetrability of each internal strand. In the case where M=9 and / or N=14, the number of intermediate or external wires is maximized and therefore the breaking strength of the cable.

[0066] In a third variant, Q=4, M=9 or 10 and N=14 or 15. In the case where M=9 and / or N=14, the desaturation of the intermediate or external layer of each internal strand is favored and therefore the penetrability of each internal strand. In the case where M=10 and / or N=15, the number of intermediate or external wires is maximized and therefore the breaking strength of the cable.

[0067] In these embodiments, in particular those where Q=3 or 4, there is a risk of seeing a very strong propagation of the corrosive agents between the Q=3 or 4 internal wires which delimit a central capillary very favorable to their propagation along the strand, when the strand is insufficiently penetrated. This drawback can be overcome by making the strand penetrable by the elastomer composition which then prevents the corrosive agents from accessing the central capillary, and in the best case where the central capillary is itself penetrated, the propagation of these corrosive agents along the strand.

[0068] Advantageously, the sum SI2 of the inter-wire distances of the intermediate layer is such that SI2 < d3 with d3 being the diameter of each external wire of each internal strand, preferably SI2 ≤ 0.8 x d3. The sum SI2 is the sum of the inter-wire distances separating each pair of adjacent wires of the intermediate layer. The inter-wire distance of a layer is defined, on a section of the cable perpendicular to the main axis of the cable, as the shortest distance which separates, on average, two adjacent wires of the layer. Thus, the inter-wire distance is calculated by dividing the sum SI2 by the number of spaces separating the wires of the intermediate layer. The diameter d3 of the external wires of the external layer of each internal strand being preferably greater than the sum SI2, the external wires are prevented from penetrating into the intermediate layer.This ensures good architectural stability, which also reduces the risk of modification of the radial passage windows of the elastomer composition and therefore the risk of degrading the good penetrability of each internal strand.

[0069] Advantageously, the intermediate layer of each internal strand is desaturated.

[0070] By definition, a desaturated layer of yarns is such that there is sufficient space between the yarns to allow the passage of an elastomer composition. Thus, a desaturated layer means that the yarns in that layer do not touch each other and there is sufficient space between two adjacent yarns in the layer to allow the passage of an elastomer composition through the layer. In contrast, a saturated layer of yarns is such that there is not sufficient space between the yarns in the layer to allow the passage of an elastomer composition, for example because the yarns in the layer touch each other in pairs.

[0071] Advantageously, the inter-wire distance of the intermediate layer of each internal strand is greater than or equal to 5 µm. Preferably, the inter-wire distance of the intermediate layer of each internal strand is greater than or equal to 15 µm, more preferably greater than or equal to 35 µm, even more preferably greater than or equal to 50 µm and very preferably greater than or equal to 60 µm.

[0072] The desaturation of the intermediate layer of each internal strand advantageously facilitates the passage of the elastomer composition to the center of each internal strand and therefore makes each internal strand less sensitive to corrosion.

[0073] In an embodiment favoring the compromise between penetrability of each internal strand and breaking strength, the intermediate layer of each internal strand is incompletely unsaturated.

[0074] By definition, an incompletely unsaturated layer of wires is such that there is not enough space in this layer to add at least one (X+1)th< wire of the same diameter as the X wires of the layer. In this case, there is not enough space in the intermediate layer to add at least one (M+1)th< intermediate wire of the same diameter as the M intermediate wires of the intermediate layer. In other words, by incompletely unsaturated inner strand intermediate layer, it is meant that the sum SI2 of the inter-wire distances I2 of the intermediate layer is less than the diameter d2 of the intermediate wires of the intermediate layer. Thus, advantageously, the sum SI2 of the inter-wire distances of the intermediate layer of each inner strand is such that SI2 < d2.

[0075] The incomplete unsaturation of the intermediate layer of each internal strand ensures architectural stability of the intermediate layer. This reduces the risk of an external wire penetrating the intermediate layer, which would modify the radial passage windows of the elastomer composition and therefore degrade the good penetrability of each internal strand. In addition, the incomplete unsaturation of the intermediate layer of each internal strand ensures that each internal strand comprises a relatively high number of intermediate wires and therefore has a relatively high breaking strength.

[0076] In another embodiment promoting the penetrability of each inner strand, the intermediate layer of each inner strand is completely unsaturated.

[0077] By definition, a completely unsaturated layer of wires is such that there is enough space in this layer to add at least one (X+1)th wire of the same diameter as the X wires of the layer, several wires then being able to be in contact with each other or not. In this case, there is enough space in the intermediate layer of each internal strand to add at least one (M+1)th intermediate wire of the same diameter as the M intermediate wires of the intermediate layer. In other words, by completely unsaturated internal strand intermediate layer, it is meant that the sum SI2 of the inter-wire distances I2 of the intermediate layer is greater than or equal to the diameter d2 of the intermediate wires of the intermediate layer. Thus, advantageously, the sum SI2 of the inter-wire distances of the intermediate layer of each external strand is such that SI2 ≥ d2.

[0078] Advantageously, the outer layer of each inner strand is desaturated, preferably completely unsaturated. Similarly to the intermediate layer, desaturation of the outer layer of each inner strand advantageously facilitates the passage of the elastomer composition into and through each inner strand and therefore makes each inner strand less susceptible to corrosion.

[0079] Advantageously, the inter-wire distance of the outer layer of each inner strand is greater than or equal to 5 µm. Preferably, the inter-wire distance of the outer layer of each inner strand is greater than or equal to 15 µm, more preferably greater than or equal to 35 µm, even more preferably greater than or equal to 50 µm and very preferably greater than or equal to 60 µm.

[0080] By definition, a completely unsaturated layer of wires is such that there is enough space in this layer to add at least one (X+1)th< wire of the same diameter as the X wires of the layer, several wires then being able to be in contact with each other or not. In this case, there is enough space in the outer layer of each inner strand to add at least one (N+1)th< outer wire of the same diameter as the N outer wires of the outer layer. In other words, by completely unsaturated outer layer of inner strand, it is meant that the sum SI3 of the inter-wire distances I3 of the outer layer is greater than or equal to the diameter d3 of the outer wires of the outer layer. Thus, advantageously, the sum SI3 of the inter-wire distances of the outer layer of each inner strand is such that SI3 ≥ d3. The sum SI3 is the sum of the inter-wire distances separating each pair of adjacent wires of the outer layer.The inter-wire distance of a layer is defined, on a section of the cable perpendicular to the main axis of the cable, as the shortest distance which separates, on average, two adjacent wires of the layer. Thus, the inter-wire distance is calculated by dividing the sum SI3 by the number of spaces separating the wires of the outer layer.

[0081] Complete unsaturation of the outer layer of each inner strand maximizes the penetration of the elastomer composition into each inner strand and therefore makes each inner strand even less susceptible to corrosion.

[0082] In preferred embodiments, each internal wire of each internal strand has a diameter d1 greater than or equal to the diameter d2 of each intermediate wire of each internal strand and very preferably 1≤d1 / d2≤1.10. The use of diameters such that d1>d2 makes it possible to promote the penetrability of the elastomer composition through the intermediate layer. When d1>d2, it is very preferably d1 / d2≤1.10 which makes it possible, on the one hand, to control the architectural stability of the intermediate layer and, on the other hand, to make the present invention of even greater interest due to the relatively low desaturation created by the difference between d1 and d2. The use of diameters such that d1=d2 makes it possible to limit the number of different wires to be managed during the manufacture of the cable but also to make the present invention of even greater interest due to the lack of desaturation created by the equality between d1 and d2.

[0083] In preferred embodiments, each inner wire of each inner strand has a diameter d1 greater than or equal to the diameter d3 of each outer wire of each inner strand and very preferably 1≤d1 / d3≤1.10. The use of diameters such that d1>d3 makes it possible to promote the penetrability of the elastomer composition through the outer layer. When d1>d3, it is very preferentially d1 / d3≤1.10 which makes it possible, on the one hand, to control the architectural stability of the outer layer and, on the other hand, to make the present invention of even greater interest due to the relatively low desaturation created by the difference between d1 and d3. The use of diameters such that d1=d3 makes it possible to limit the number of different wires to be managed during the manufacture of the cable but also to make the present invention of even greater interest due to the lack of desaturation created by the equality between d1 and d3.

[0084] In preferred embodiments, each intermediate wire of each inner strand has a diameter d2 equal to the diameter d3 of each outer wire of each inner strand. The use of diameters such that d2=d3 makes it possible to limit the number of different wires to be managed during the manufacture of the cable.

[0085] Advantageously, each internal strand is of the non-rubberized in situ type. By non-rubberized in situ, it is meant that before assembly of the external layer of the cable and before assembly of the cable, each internal strand is made up of the wires of the different layers and is free of polymer composition, in particular elastomer composition. External strands of the cable according to the invention

[0086] Advantageously, the outer layer of each outer strand is desaturated, preferably completely unsaturated. Desaturation of the outer layer of each outer strand advantageously facilitates the passage of the elastomer composition to the center of each outer strand and therefore makes each outer strand less susceptible to corrosion.

[0087] Advantageously, the inter-wire distance of the outer layer of each outer strand is greater than or equal to 5 µm. Preferably, the inter-wire distance of the outer layer of each outer strand is greater than or equal to 15 µm, more preferably greater than or equal to 35 µm, even more preferably greater than or equal to 50 µm and very preferably greater than or equal to 60 µm.

[0088] The outer layer of each outer strand is preferably completely unsaturated.

[0089] By definition, a completely unsaturated layer of wires is such that there is enough space in this layer to add at least one (X'+1)th wire of the same diameter as the X' wires of the layer, several wires then being able to be in contact with each other or not. In this case, there is enough space in the outer layer to add at least one (N'+1)th wire of the same diameter as the N' wires of the outer layer. In other words, by completely unsaturated outer layer of outer strand, it is meant that the sum SI3' of the inter-wire distances I3' of the outer layer is greater than or equal to the diameter d3' of the outer wires of the outer layer. Thus, advantageously, the sum SI3' of the inter-wire distances of the outer layer of each outer strand is such that SI3' ≥ d3'. The sum SI3' is the sum of the inter-wire distances separating each pair of adjacent wires of the outer layer.The inter-wire distance of a layer is defined, on a section of the cable perpendicular to the main axis of the cable, as the shortest distance which separates, on average, two adjacent wires of the layer. Thus, the inter-wire distance is calculated by dividing the sum SI3' by the number of spaces separating the wires of the outer layer.

[0090] Complete unsaturation of the outer layer of each outer strand maximizes the penetration of the elastomer composition into each outer strand and therefore makes each outer strand even less susceptible to corrosion.

[0091] In preferred embodiments, each inner wire of each outer strand has a diameter d1' greater than or equal to the diameter d3' of each outer wire of each inner outer strand and very preferably 1≤d1' / d3'≤1.10. The use of diameters such that d1'>d3' makes it possible to promote the penetrability of the elastomer composition through the outer layer. When d1'>d3', d1' / d3' is very preferably ≤1.10, which makes it possible, on the one hand, to control the architectural stability of the outer layer and, on the other hand, to make the good penetrability of each outer strand of even greater interest due to the relatively low desaturation created by the difference between d1' and d3'.The use of diameters such as d1'=d3' makes it possible to limit the number of different wires to be managed during the manufacture of the cable but also to make the present invention of even greater interest due to the lack of desaturation created by the equality between d1' and d3'.

[0092] In one embodiment, each outer strand is of the in-situ gummed type. Such a strand comprises, before assembly of the cable, a layer of a polymer composition, in particular an elastomer composition arranged between at least two radially adjacent layers of wires, optionally between each radially adjacent layer of wires. Such an in-situ gummed strand is described in particular in WO2010054790.

[0093] In another embodiment, each outer strand is of the non-rubberized in situ type. By non-rubberized in situ, it is meant that before assembly of the cable, each outer strand is made up of the wires of the different layers and is free of polymer composition, in particular elastomer composition. Two-layer outer strands

[0094] In one embodiment that favors the compromise between cable diameter and breaking strength, each outer strand is two-layered. In this embodiment, the outer layer of each outer strand is wrapped around the inner layer of the outer strand in contact with the inner layer of the outer strand. In this embodiment, each outer strand comprises a wire assembly consisting of two layers of wires, no more and no less, that is, the wire assembly has two layers of wires, not one, not three, but only two.

[0095] In preferred embodiments, Q'=1, 2, 3 or 4.

[0096] In one embodiment, Q'=1, N'=5 or 6, preferably Q'=1, N'=6.

[0097] In preferred embodiments making it possible to increase the breaking strength of the cable compared to the embodiment in which Q'=1, Q'=2, 3 or 4, preferably Q'=3 or 4. Unlike the embodiment in which Q'=1 and in which there is a risk of seeing, under the effect of repeated compression forces applied to the cable, the internal wire of each external strand coming out radially from each external strand and even from the cable, the presence of several wires in the internal layer of each internal strand (Q'>1), makes it possible to reduce this risk, the compression forces then being distributed over the plurality of wires of the internal layer.

[0098] In these embodiments in which Q'>1, each outer strand advantageously has cylindrical layers, i.e. in which the Q' inner wires are wound at a pitch p1' and in an inner layer direction of each outer strand and the N' outer wires are wound around the intermediate layer at a pitch p3' and in an outer layer direction of each outer strand, p1' being different from p3' and / or the inner layer direction of each outer strand being different from the outer layer direction of each inner strand.

[0099] In these preferred embodiments in which Q'>1, in particular those where Q'=3 or 4, there is a risk, when the strand is insufficiently penetrated, of seeing a very strong propagation of the corrosive agents between the Q'=3 or 4 internal wires which delimit a central capillary very favorable to their propagation along each strand. This drawback can be overcome by making the strand penetrable by the elastomer composition which then prevents the corrosive agents from accessing the central capillary, and in the best case where the central capillary is itself penetrated, the propagation of these corrosive agents along the strand.

[0100] In preferred embodiments wherein Q'>1, N'=7, 8, 9 or 10, preferably N'=8, 9 or 10 and more preferably N'=8 or 9.

[0101] In a first variant, Q'=2 and N'=7 or 8, preferably Q'=2, N'=7.

[0102] In a second variant, Q'=3 and N'=7, 8 or 9, preferably Q'=3, N'=8.

[0103] In a third variant, Q'=4 and N'=7, 8, 9 or 10, preferably Q'=4, N'=9.

[0104] In a first embodiment of the cable, the intermediate layer of each inner strand is wound around the inner layer of each inner strand in a winding direction identical to the winding direction of the cable.

[0105] Advantageously, the inner layer of the cable is wound in an inner layer direction of the cable and each intermediate and outer layer of each inner strand is wound in the same winding direction as the inner layer direction of the cable.

[0106] Advantageously, the outer layer of the cable is wound in one direction of the outer layer of the cable and each inner (when Q'>1), intermediate and outer layer of each outer strand is wound in the same winding direction as the direction of the outer layer of the cable.

[0107] In one embodiment, the direction of the inner layer of the cable and the direction of the outer layer of the cable are the same. In this embodiment, manufacturing is relatively easy because it is not necessary, unlike in the previous embodiment, to differentiate the winding directions between the inner and outer layers of the cable. However, the contacts between the outer wires of the outer layers of the inner and outer strands are relatively long, which can, in certain combinations of pitches, diameters and cable architectures, generate assembly defects due, for example, to unwanted sliding of the outer strands in the grooves formed between the inner strands.

[0108] In another embodiment, the direction of the inner layer of the cable and the direction of the outer layer of the cable are opposite. In this embodiment, the risk of possible unwanted sliding of the outer strands in grooves formed between the inner strands due to a crossing between the inner and outer strands is reduced. Three-layer outer strands

[0109] In another particularly advantageous embodiment improving the breaking strength of the cable, each outer strand is three-layered and comprises: an inner layer consisting of Q'≥1 inner threads, an intermediate layer consisting of M'>1 intermediate threads wound around the inner layer, and an outer layer consisting of N'>1 outer threads wound around the intermediate layer.

[0110] In this embodiment, the outer layer of each outer strand is wrapped around the intermediate layer of the outer strand in contact with the intermediate layer of the outer strand and the intermediate layer of the outer strand is wrapped around the inner layer of the outer strand in contact with the inner layer of the outer strand. In this embodiment, each inner strand comprises a wire assembly consisting of three layers of wires, no more and no less, i.e., the wire assembly has three layers of wires, not two, not four, but only three.

[0111] In preferred embodiments, Q'=1, 2, 3 or 4.

[0112] In embodiments, Q'=1. In the embodiment where Q'=1 and when the cable is insufficiently penetrated, there is a risk of seeing, under the effect of repeated compression forces applied to the cable, the internal wire of each external strand exiting radially from each external strand and even from the cable. Thanks to good penetration of each external strand, and despite Q'=1, the elastomer composition acts as a hooping layer around each external strand, in particular around the external and intermediate layers of each external strand preventing the exit of the internal wire even under repeated compression forces.

[0113] In these embodiments in which Q'=1, each outer strand advantageously has cylindrical layers, i.e. in which the M' intermediate wires are wound around the inner layer at a pitch p2' and in an intermediate layer direction of the outer strand and the N' outer wires are wound around the intermediate layer at a pitch p3' and in an external layer direction of the outer strand, p2' is different from p3' and / or the intermediate layer direction of the outer strand is different from the external layer direction of the outer strand.

[0114] In one embodiment, Q'=1, M'=5 or 6 and N'=10, 11 or 12, preferably Q'=1, M'=5 or 6 and N'=10 or 11 and more preferably Q'=1, M'=6 and N'=11.

[0115] In preferred embodiments allowing to increase the breaking force of the cable compared to the embodiment in which Q'=1, Q'=2, 3 or 4, preferably Q'=3 or 4.

[0116] In these embodiments in which Q'>1, each outer strand advantageously has cylindrical layers, i.e. in which the Q' inner wires are wound at a pitch p1' and in an inner layer direction of the outer strand, the M' intermediate wires are wound around the inner layer at a pitch p2' and in an intermediate layer direction of the outer strand, the N' outer wires are wound around the intermediate layer at a pitch p3' and in an outer layer direction of the outer strand, p1', p2' and p3' are different two by two and / or the directions of the adjacent layers of the outer strand are different.

[0117] Preferably, we also have the M' intermediate wires wound around the inner layer at a pitch p2' and the N' external wires wound around the intermediate layer at a pitch p3', the pitches p2' and p3' verifying: 0.33 ≤ (p3'-p2') / p3' ≤ 0.45 in the case where Q'=2, 0.35 ≤ (p3'-p2') / p3' ≤ 0.42 in the case where Q'=3, 0.28 ≤ (p3'-p2') / p3' ≤ 0.43 in the case where Q'=4.

[0118] Such a ratio (p3'-p2') / p3' makes it possible to obtain relatively large radial passage windows for the elastomer composition within each external strand.

[0119] Advantageously, steps p2' and p3' verify: 0.36 ≤ (p3'-p2') / p3', preferably 0.38 ≤ (p3'-p2') / p3' in the case where Q'=2, 0.36 ≤ (p3'-p2') / p3', preferably 0.38 ≤ (p3'-p2') / p3' in the case where Q'=3, 0.32 ≤ (p3'-p2') / p3', preferably 0.36 ≤ (p3'-p2') / p3' in the case where Q'=4.

[0120] In a similar way to the internal strand, the greater the ratio (p3'-p2') / p3', in other words the greater the difference between p3' and p2', the better the architectural stability of each external strand.

[0121] Advantageously, steps p2' and p3' verify: (p3'-p2') / p3' ≤ 0.42 and preferably (p3'-p2') / p3' ≤ 0.40 in the case where Q'=2, (p3'-p2') / p3' ≤ 0.40 in the case where Q'=3, (p3'-p2') / p3' ≤ 0.40 and preferably (p3'-p2') / p3' ≤ 0.38 in the case where Q'=4.

[0122] Below these values, the dimension of the radial passage windows of the elastomer composition is maximum and allows the penetrability of each external strand to be optimized.

[0123] Advantageously, the pitch p1' is such that 3 mm ≤ p1' ≤ 16 mm, preferably 4 mm ≤ p1' ≤ 13 mm and more preferably 5 mm ≤ p1' ≤ 10 mm.

[0124] Advantageously, the pitch p2' is such that 8 mm ≤ p2' ≤ 20 mm, preferably 9 mm ≤ p2' ≤ 18 mm and more preferably 10 mm ≤ p2' ≤ 16 mm.

[0125] Advantageously, the pitch p3' is such that 10 mm ≤ p3' ≤ 40 mm, preferably 12 mm ≤ p3' ≤ 30 mm and more preferably 15 mm ≤ p3' ≤ 25 mm.

[0126] Steps p1', p2' and p3' in these preferred ranges make it possible to obtain a cable with mechanical properties compatible with pneumatic use, at a relatively low cost and linear mass of the cable.

[0127] In these preferred embodiments in which Q'>1, in particular those where Q'=3 or 4, there is a risk, when the strand is insufficiently penetrated, of seeing a very strong propagation of the corrosive agents between the Q'=3 or 4 internal wires which delimit a central capillary very favorable to their propagation along each strand. This drawback can be overcome by making the strand penetrable by the elastomer composition which then prevents the corrosive agents from accessing the central capillary, and in the best case where the central capillary is itself penetrated, the propagation of these corrosive agents along the strand.

[0128] In preferred embodiments wherein Q'>1, Q'=2, 3 or 4, M'=7, 8, 9 or 10, N'=13, 14 or 15, preferably Q'=3 or 4, M'=8, 9 or 10, N'=14 or 15, more preferably Q'=3, M'=8 or 9 and N'=14 or 15 and even more preferably Q'=3, M'=9 and N'=15.

[0129] Advantageously, the sum SI2' of the inter-wire distances of the intermediate layer is such that SI2' < d3' with d3' being the diameter of each external wire of each external strand, preferably SI2' ≤ 0.8 x d3'. In a similar manner to the internal strand, the diameter d3' of the external wires of the external layer of each external strand being preferably greater than the sum SI'2, the external wires are prevented from penetrating into the intermediate layer. This ensures good architectural stability, which reduces the risk of modification of the radial passage windows of the elastomer composition and therefore the risk of degrading the good penetrability of each external strand. The sum SI2' is the sum of the inter-wire distances separating each pair of adjacent wires of the intermediate layer.The inter-wire distance of a layer is defined, on a section of the cable perpendicular to the main axis of the cable, as the shortest distance which separates, on average, two adjacent wires of the layer. Thus, the inter-wire distance is calculated by dividing the sum SI2' by the number of spaces separating the wires of the intermediate layer.

[0130] Advantageously, the intermediate layer of each outer strand is desaturated.

[0131] Advantageously, the inter-wire distance of the intermediate layer of each outer strand is greater than or equal to 5 µm. Preferably, the inter-wire distance of the intermediate layer of each outer strand is greater than or equal to 15 µm, more preferably greater than or equal to 35 µm, even more preferably greater than or equal to 50 µm and very preferably greater than or equal to 60 µm.

[0132] The desaturation of the intermediate layer of each outer strand advantageously facilitates the passage of the elastomer composition to the center of each outer strand and therefore makes each outer strand less sensitive to corrosion.

[0133] In an embodiment favoring the compromise between penetrability of each outer strand and breaking strength, the intermediate layer of each outer strand is incompletely unsaturated.

[0134] By definition, an incompletely unsaturated layer of wires is such that there is not enough space in this layer to add at least one (X'+1)th< wire of the same diameter as the X' wires of the layer. In this case, there is not enough space in the intermediate layer to add at least one (M'+1)th< intermediate wire of the same diameter as the M' intermediate wires of the intermediate layer. In other words, by incompletely unsaturated outer strand intermediate layer, it is meant that the sum SI2' of the inter-wire distances I2' of the intermediate layer is less than the diameter d2' of the intermediate wires of the intermediate layer. Thus, advantageously, the sum SI2' of the inter-wire distances of the intermediate layer of each outer strand is such that SI2' < d2'.

[0135] The incomplete unsaturation of the intermediate layer of each outer strand ensures architectural stability of the intermediate layer. In addition, the incomplete unsaturation of the intermediate layer of each outer strand ensures that the outer strand comprises a relatively high number of intermediate wires and therefore has a relatively high breaking strength.

[0136] In another embodiment promoting the penetrability of each outer strand, the intermediate layer of each outer strand is completely unsaturated.

[0137] By definition, a completely unsaturated layer of wires is such that there is enough space in this layer to add at least one (X'+1)th wire of the same diameter as the X' wires of the layer, several wires then being able to be in contact with each other or not. In this case, there is enough space in the intermediate layer of each outer strand to add at least one (M'+1)th intermediate wire of the same diameter as the M' intermediate wires of the intermediate layer. In other words, by completely unsaturated outer strand intermediate layer, it is meant that the sum SI2' of the inter-wire distances I2' of the intermediate layer is greater than or equal to the diameter d2' of the intermediate wires of the intermediate layer. Thus, advantageously, the sum SI2' of the inter-wire distances of the intermediate layer of each outer strand is such that SI2' ≥ d'2.

[0138] In preferred embodiments, each inner wire of each outer strand has a diameter d1' greater than or equal to the diameter d2' of each intermediate wire of each outer strand and very preferably 1≤d1' / d2'≤1.10. The use of diameters such that d1'>d2' makes it possible to promote the penetrability of the elastomer composition through the intermediate layer. When d1'>d2', d1' / d2' is very preferably ≤1.10, which makes it possible, on the one hand, to control the architectural stability of the intermediate layer and, on the other hand, to make the good penetrability of each outer strand of even greater interest due to the relatively low desaturation created by the difference between d1' and d2'.The use of diameters such as d1'=d2' makes it possible to limit the number of different wires to be managed during the manufacture of the cable but also to make the present invention of even greater interest due to the lack of desaturation created by the equality between d1' and d2'.

[0139] In preferred embodiments, each intermediate wire of each outer strand has a diameter d2' equal to the diameter d3' of each outer wire of each outer strand. The use of diameters such that d2'=d3' makes it possible to limit the number of different wires to be managed during the manufacture of the cable. PNEUMATIC ACCORDING TO THE INVENTION

[0140] Another object of the invention is a tire comprising a cable as defined above.

[0141] The cable is particularly intended for industrial vehicles chosen from heavy vehicles such as "Heavy Goods Vehicles" - i.e., metro, bus, road transport equipment (trucks, tractors, trailers), off-road vehicles -, agricultural or civil engineering equipment, other transport or handling vehicles.

[0142] Preferably, the tire is for a civil engineering type vehicle. The tire has a WRU type dimension in which, in a manner known to those skilled in the art, W denotes: the nominal aspect ratio H / B as defined by ETRTO, when in the form H / B, H being the height of the tyre section and B being the width of the tyre section, H.00 or B.00, when 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 rim seat on which the tire is intended to be mounted, R designates the type of carcass reinforcement of the tire, here radial. Examples of such dimensions are for example 40.00 R 57 or 59 / 80 R 63.

[0143] We preferably have U≥35, more preferably U≥49 and more preferably U≥57.

[0144] In one embodiment, the tire comprises a carcass reinforcement anchored in two beads and surmounted radially by a crown reinforcement itself surmounted by a tread, the crown reinforcement being joined to said beads by two sidewalls, the carcass reinforcement comprising at least one cable as defined above.

[0145] In another embodiment, the tire comprises a carcass reinforcement anchored in two beads and surmounted radially by a crown reinforcement itself surmounted by a tread, the crown reinforcement being joined to said beads by two sidewalls and comprising at least one cable as defined above.

[0146] Advantageously, the carcass reinforcement comprises at least one carcass ply comprising metallic carcass reinforcing wire elements, each metallic carcass reinforcing wire element making an angle of between 80° and 90° with the circumferential direction of the tire.

[0147] Advantageously, the crown reinforcement comprises a working reinforcement comprising at least one cable as defined above.

[0148] Advantageously, the working reinforcement comprises at least one working ply comprising metallic working reinforcing wire elements arranged substantially parallel to each other, each metallic working reinforcing wire element making an angle at most equal to 60°, preferably ranging from 15° to 40° with the circumferential direction of the tire and being formed by a cable as defined above.

[0149] In an advantageous embodiment, the working reinforcement comprises at least first and second working plies, each first and second working ply respectively comprising first and second working metallic reinforcing wire elements arranged substantially parallel to each other in each first and second working ply, each first and second working metallic reinforcing wire element making an angle at most equal to 60°, preferably ranging from 15° to 40° with the circumferential direction of the tire and being formed by a cord as defined above.Optionally, the first and second working metal reinforcing wire elements are crossed from one working ply to the other, that is to say that the orientation of the angle made by the first working metal reinforcing wire elements with the circumferential direction of the tire is opposite to the orientation of the angle made by the second working metal reinforcing wire elements with the circumferential direction of the tire.

[0150] Advantageously, the crown reinforcement comprises a protective reinforcement comprising at least one protective ply comprising protective metallic reinforcing wire elements arranged substantially parallel to each other, each protective metallic reinforcing wire element making an angle at least equal to 10°, preferably ranging from 10° to 35° and preferentially from 15° to 30° with the circumferential direction of the tire.

[0151] In an advantageous embodiment, the protective reinforcement comprises first and second protective plies, each first and second protective plies respectively comprising first and second protective metallic reinforcing wire elements arranged substantially parallel to each other in each first and second protective ply, each first and second protective metallic reinforcing wire element making an angle at least equal to 10°, preferably ranging from 10° to 35° and preferentially from 15° to 30° with the circumferential direction of the tire.

[0152] In a preferred embodiment, the protective reinforcement is radially interposed between the tread and the working reinforcement.

[0153] Advantageously, the crown reinforcement comprises an additional reinforcement comprising at least one additional ply comprising additional metallic reinforcing wire elements arranged substantially parallel to each other in the additional ply, each additional metallic reinforcing wire element making an angle at most equal to 10°, preferably ranging from 5° to 10° with the circumferential direction of the tire.

[0154] In an advantageous embodiment, the additional reinforcement comprises first and second additional plies, each first and second additional ply respectively comprising first and second additional metallic reinforcing wire elements arranged substantially parallel to each other in each first and second additional ply, each first and second additional metallic reinforcing wire element making an angle at most equal to 10°, preferably ranging from 5° to 10° with the circumferential direction of the tire.

[0155] The invention will be better understood upon reading the following description, given solely as a non-limiting example and with reference to the drawings in which: there figure 1 is a sectional view perpendicular to the circumferential direction of a tire according to the invention; figure 2 is a detailed view of area II of the figure 1; THE figures 3 , 4 and 5 are schematic sectional views perpendicular to the axis of the cable (assumed to be rectilinear and at rest) of cables according to respectively first, second and third embodiments of the invention; figures 6, 7 and 8 are views similar to those of the figures 3 , 4 and 5 of cables according to respectively fourth, fifth and sixth embodiments of the invention; the figures 9, 10 and 11 are views similar to those of the figures 3 , 4 and 5 of cables according to the seventh, eighth and ninth embodiments of the invention respectively; figures 12, 13 and 14 are views similar to those of the figures 3 , 4 and 5 of cables according to respectively tenth, eleventh and twelfth embodiments of the invention; the figures 15, 16 and 17 are views similar to those of the figures 3 And 4 of cables according to respectively thirteenth, fourteenth and fifteenth embodiments of the invention; the figure 18 is a schematic projection view on a plane comprising the axis of an external strand before assembly of the cable according to the first embodiment of the invention; and the figure 19 is a detail view of zone XVIII showing a radial passage window delimited by wires of an intermediate layer and wires of an external layer of each internal strand of figure 24.

[0156] Any interval of values designated by the expression "between a and b" represents the domain of values from more than a to less than b (i.e., excluding limits a and b), while any interval of values designated by the expression "from a to b" means the domain of values from the limit "a" to the limit "b", i.e., including the strict limits "a" and "b". EXAMPLE OF A TIRE ACCORDING TO THE INVENTION

[0157] In the figures, a reference X, Y, Z is shown corresponding to the usual axial (X), radial (Y) and circumferential (Z) orientations of a tire.

[0158] The “median circumferential plane” M of the tire is the plane which is normal to the axis of rotation of the tire and which is located equidistant from the annular reinforcement structures of each bead and passes through the middle of the crown reinforcement.

[0159] It has been represented on the Figures 1 and 2 a tire according to the invention and designated by the general reference 10.

[0160] The 10 tire is for heavy vehicles of the civil engineering type, for example of the “dumper” type. Thus, the 10 tire has a dimension of type 53 / 80R63.

[0161] The tire 10 comprises a crown 12 reinforced by a crown reinforcement 14, two sidewalls 16 and two beads 18, each of these beads 18 being reinforced with an annular structure, here a bead wire 20. The crown reinforcement 14 is radially surmounted by a tread 22 and joined to the beads 18 by the sidewalls 16. A carcass reinforcement 24 is anchored in the two beads 18, and is here wound around the two bead wires 20 and comprises a turn-up 26 arranged towards the outside of the tire 20 which is here shown mounted on a rim 28. The carcass reinforcement 24 is radially surmounted by the crown reinforcement 14.

[0162] The carcass reinforcement 24 comprises at least one carcass ply 30 comprising metallic carcass reinforcing wire elements 31 and extending from one bead 18 to the other so as to make an angle of between 80° and 90° with the circumferential direction Z of the tire 10.

[0163] The tire 10 also comprises a sealing ply 32 made of an elastomer (commonly called inner rubber) 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 air coming from the space inside the tire 10.

[0164] The crown reinforcement 14 comprises, radially from the outside to the inside of the tire 10, a protective reinforcement 36 arranged radially inside the tread 22, a working reinforcement 38 arranged radially inside the protective reinforcement 36 and an additional reinforcement 80 arranged radially inside the working reinforcement 38. The protective reinforcement 36 is thus radially interposed between the tread 22 and the working reinforcement 38. The working reinforcement 38 is radially interposed between the protective reinforcement 36 and the additional reinforcement 80.

[0165] The protective reinforcement 36 comprises first and second protective plies 42, 44, the first ply 42 being arranged radially inside the second ply 44. Each first and second protective ply 42, 44 respectively comprises first and second protective metallic reinforcing wire elements 43, 45 arranged substantially parallel to each other in each first and second protective ply 42, 44. Each first and second protective metallic reinforcing wire element 43, 45 makes an angle at least equal to 10°, preferably ranging from 10° to 35° and preferentially from 15° to 30° with the circumferential direction Z of the tire.

[0166] The working reinforcement 38 comprises first and second working plies 46, 48, the first ply 46 being arranged radially inside the second ply 48. Each first and second working ply 46, 48 respectively comprises first and second working metallic reinforcing wire elements 47, 49 arranged substantially parallel to each other in each first and second working ply 46, 48. Each first and second working metallic reinforcing wire element 47, 49 makes an angle at most equal to 60°, preferably ranging from 15° to 40° with the circumferential direction Z of the tire 10.Optionally, the first and second working metal reinforcing wire elements 47, 49 are crossed from one working ply to the other, that is to say that the orientation of the angle made by the first working metal reinforcing wire elements 47 with the circumferential direction Z of the tire 10 is opposite to the orientation of the angle made by the second working metal reinforcing wire elements 49 with the circumferential direction Z of the tire 10.

[0167] The additional reinforcement 80, also called a limiting block, the function of which is to partially absorb the mechanical stresses of inflation, comprises first and second additional plies 82, 84, each first and second additional ply 82, 84 respectively comprising first and second additional metallic reinforcing wire elements 83, 85 arranged substantially parallel to each other in each first and second additional ply 82, 84. Each first and second additional metallic reinforcing wire element 83, 85 makes an angle at most equal to 10°, preferably ranging from 5° to 10° with the circumferential direction Z of the tire 10. The additional metallic reinforcing wire elements are for example as described in FR 2 419 181 or FR 2 419 182.

[0168] In one embodiment, each first and second working metal reinforcing wire element 47, 49 is formed by a cable according to the invention, for example the cable 50 described below.

[0169] In another embodiment, each metal wire reinforcement element of the carcass 31 is formed by a cable according to the invention, for example the cable 50 described below.

[0170] In yet another embodiment, each first and second working metal reinforcing wire element 47, 49 and each carcass metal reinforcing wire element 31 is formed by a cable according to the invention, these cables being able to be identical or different depending on whether they are metal reinforcing wire elements 31, 47 or 49. CABLE ACCORDING TO A FIRST EMBODIMENT OF THE INVENTION

[0171] It has been represented on the figure 3 the cable 50 according to a first embodiment of the invention.

[0172] The cable 50 is metallic and is of the multi-strand type with two cylindrical layers. Thus, it is understood that the layers of strands constituting the cable 50 are two in number, neither more nor less. The layers of strands are adjacent and concentric. The cable 50 is devoid of polymeric composition and elastomer composition when it is not integrated into the tire.

[0173] The cable 50 comprises an inner layer CI of the cable 50 as well as an outer layer CE of the cable 50. The inner layer CI is made up of K>1 inner strands TI wound in a helix. The outer layer CE is made up of L>1 outer strands, i.e. several outer strands TE. In this case, K=2, 3 or 4, preferably K=3 or 4 and here K=3. The outer layer CE is made up of L>1 outer strands TE wound around the inner layer CI of the cable. In this case, L=7, 8, 9 or 10, preferably L=8, 9 or 10 and more preferably L=8 or 9 and in this case L=9. The cable 50 also comprises a hoop F made up of a single hoop wire.

[0174] The inner layer CI of the cable is wound in a helix according to an inner layer direction of the cable, here Z, according to a pitch pi and here pi=80 mm and the outer layer CE is wound in a helix according to an outer layer direction of the cable, here Z according to a pitch pe and here pe=100 mm. As pi is different from pe, the cable has cylindrical layers.

[0175] The hoop F is wound around the outer layer CE in a hoop winding direction, here opposite to the winding direction of the cable, in this case in the direction S. The hoop wire is wound helically around the outer strands TE in a pitch pf such that 2 mm ≤ pf ≤ 10 mm and preferably 3 mm ≤ pf ≤ 8 mm. Here pf=5.1 mm.

[0176] The assembly consisting of the inner CI and outer CE layers, i.e. cable 50 without the band F, has a diameter D. Here, D= 6.0 mm.

[0177] The outer layer CE of the cable 50 is desaturated. The average inter-strand distance E separating two adjacent outer strands TE is greater than or equal to 150 µm and very preferably greater than or equal to 200 µm. In this embodiment, the inter-strand distance of the outer layer of outer strands is greater than or equal to 200 µm. Here, E=271 µm.

[0178] Each inner strand TI has a diameter DI and each outer strand TE has a diameter DE. In this case, here DI=1.56 mm and DE=1.32 mm.

[0179] The CE outer layer of the 50 cable is incompletely unsaturated. In fact, SIE=9 x 0.271= 2.44 mm, a value greater than DE=1.32 mm. External TE strands of cable 50

[0180] Each outer TE strand is at least two-layer. In this case, each outer TE strand is three-layer. Each outer TE strand comprises, here is made up of, three layers, no more, no less.

[0181] Each outer strand TE comprises an inner layer C1' consisting of Q' inner wire(s) F1', an intermediate layer C2' consisting of M' intermediate wires F2' wound helically around the inner layer C1' and an outer layer C3' consisting of N' outer wires F3' wound helically around the inner layer C1' and around and in contact with the intermediate layer C2'.

[0182] Q'=1, 2, 3 or 4 and more preferably here Q'=1.

[0183] With Q'=1, M'= 5 or 6 and N'=10, 11 or 12, preferably Q'=1, M'=5 or 6 and N'=10 or 11 and here Q'=1, M'=6 and N'=11.

[0184] The internal thread F1' has an infinite pitch.

[0185] The intermediate layer C2' of each outer strand TE is wound around the inner layer C1' of the outer strand TE in a winding direction of the intermediate layer of the outer strand, here in the direction Z, opposite to the winding direction of the cable S. The M' intermediate wires F2' are wound helically around the inner wire F1' in a pitch p2' such that 8 mm ≤ p2' ≤ 20 mm, preferably 9 mm ≤ p2' ≤ 18 mm and more preferably 10 mm ≤ p2' ≤ 16 mm. Here p2'=14 mm.

[0186] The outer layer C3' of each outer strand TE is wound around the inner layers C1' and intermediate C2' of the outer strand TE in a winding direction of the outer layer of the outer strand, here in the direction Z, opposite to the winding direction of the cable S and in the same direction Z as the intermediate layer C2' of each outer strand TE. The N outer wires F3' are wound helically around the M' intermediate wires F2' in a pitch p3' such that 10 mm ≤ p3' ≤ 40 mm, preferably 12 mm ≤ p3' ≤ 30 mm, more preferably 15 mm ≤ p3' ≤ 25 mm. Here p3'=20 mm.

[0187] Since p1' is different from p2' and p2' is different from p3', each outer strand TE is cylindrically layered.

[0188] The intermediate layer C2' of each outer strand TE is desaturated and incompletely unsaturated. The inter-wire distance I2' of the intermediate layer C2' separating on average the M' intermediate wires is advantageously greater than or equal to 5 µm and here equal to 9 µm. The intermediate layer C2' being incompletely unsaturated, the sum SI2' of the inter-wire distances I2' of the intermediate layer C2' is less than the diameter d2' of the intermediate wires F2' of the intermediate layer C2'. Here, the sum SI2'=6 x 0.009 = 0.05 mm, a value strictly less than d2'=0.26 mm.

[0189] The sum SI2' of the inter-wire distances I2' of the intermediate layer C2' is less than the diameter d3' of the external wires F3' of the external layer C3' and preferably less than or equal to 0.8 x d3'. Here, the sum SI2'=6 x 0.009=0.05 mm, a value strictly less than d3'=0.26 mm.

[0190] The outer layer C3' of each outer strand TE is desaturated and completely unsaturated. The inter-wire distance I3' of the outer layer C3' separating on average the N' outer wires is advantageously greater than or equal to 5 µm, preferably greater than or equal to 15 µm, more preferably greater than or equal to 35 µm and here equal to 36 µm. The sum SI3' of the inter-wire distances I3 of the outer layer C3' is greater than the diameter d3' of the outer wires F3' of the outer layer C3'. Here, the sum SI3'=11 x 0.036=0.39 mm, a value strictly greater than d3'=0.26 mm.

[0191] Each inner, intermediate and outer wire of each outer strand TE has a diameter d1', d2' and d3' respectively. Each diameter of the inner wires d1', intermediate wires d2' and outer wires d3' of each outer strand TE ranges from 0.15 mm to 0.60 mm, preferably from 0.20 mm to 0.50 mm, more preferably from 0.22 mm to 0.40 mm and even more preferably from 0.24 mm to 0.35 mm.

[0192] The inner wire F1' of each outer strand TE has a diameter d1' greater than or equal to the diameter d2' of each intermediate wire F2' of each outer strand TE and very preferably 1≤d1' / d2'≤1.10. The inner wire F1' of each outer strand TE has a diameter d1' greater than or equal to the diameter d3' of each outer wire F3' of each outer strand TE and very preferably 1≤d1' / d3'≤1.10. Each diameter d2' of each intermediate wire F2' of each outer strand TE and each diameter d3' of each outer wire F3' of each outer strand TE are such that d2'=d3'.

[0193] In this case, d1'>d2' and d1'>d3', d1' / d2'=d1' / d3'=1.08 and d1'=0.28 mm, d2'=d3'=0.26 mm. Internal strand TI of cable 50

[0194] Each TI inner strand is three-layered. Thus, each TI inner strand comprises, here is made up of, three layers, no more, no less.

[0195] Each inner strand TI comprises an inner layer C1 consisting of Q=2, 3 or 4 inner wires, an intermediate layer C2 consisting of M intermediate wires F2 wound helically around the inner layer C1 and an outer layer C3 consisting of N outer wires F3 wound helically around the inner layer C1 and around and in contact with the intermediate layer C2.

[0196] M=7, 8, 9 or 10, N=12, 13, 14 or 15 and here Q=2, M=7 or 8 and N=12 or 13. In this case, cable 50 is such that Q=2, M=7 and N=12.

[0197] The inner layer C1 of each inner strand TI is wound helically according to a winding direction of the inner layer of each inner strand, here according to the direction Z, opposite to the winding direction S of the cable. The Q inner wires F1 are wound helically according to a pitch p1 such that 3 mm ≤ p1 ≤ 16 mm, preferably 4 mm ≤ p1 ≤ 13 mm and more preferably 5 mm ≤ p1 ≤ 10 mm. Here, p1 = 6 mm.

[0198] The intermediate layer C2 of each inner strand TI is wound around the inner layer C1 of each inner strand TI in a winding direction of the intermediate layer of each inner strand, here in the direction Z, opposite to the winding direction S of the cable. The M intermediate wires F2 are wound helically around the inner wires F1 in a pitch p2 such that 8 mm ≤ p2 ≤ 20 mm, preferably 9 mm ≤ p2 ≤ 18 mm and more preferably 10 mm ≤ p2 ≤ 16 mm. Here p2 = 11 mm.

[0199] The outer layer C3 of each inner strand TI is wound around the intermediate layer C2 of each inner strand TI in a winding direction of the outer layer of each inner strand TI, here in the direction Z, opposite to the winding direction S of the cable and in the same direction Z as the inner layers C1 and intermediate C2 of each inner strand TI and in the same direction Z as the outer layer C3' of each outer strand TE. The N outer wires F3 are wound helically around the M intermediate wires F2 in a pitch p3 such that 10 mm ≤ p3 ≤ 40 mm, preferably 12 mm ≤ p3 ≤ 30 mm, more preferably 15 mm ≤ p3 ≤ 25 mm. Here p3 = 18 mm.

[0200] The steps p2 and p3 verify 0.33 ≤ (p3-p2) / p3≤ 0.45, the ratios lower than 0.36 (not included) not being part of the object of the protection of the invention as claimed.

[0201] 0.36 ≤ (p3-p2) / p3, preferably 0.38 ≤ (p3-p2) / p3.

[0202] (p3-p2) / p3 ≤ 0.42 and preferably (p3-p2) / p3 ≤ 0.40.

[0203] In this case, (p3-p2) / p3=0.39.

[0204] Since p1 is different from p2 and p2 is different from p3, each inner strand is cylindrically layered.

[0205] The intermediate layer C2 of each internal strand TI is desaturated and here completely unsaturated. The inter-wire distance I2 of the intermediate layer C2 separating on average the M intermediate wires is advantageously greater than or equal to 5 µm, preferably greater than or equal to 15 µm, more preferably greater than or equal to 35 µm and even more preferably to 50 µm and in this embodiment, the inter-wire distance I2 is very preferably greater than or equal to 60 µm and here equal to 75 µm. The intermediate layer C2 being completely unsaturated, the sum SI2 of the inter-wire distances I2 of the intermediate layer C2 is less than the diameter d2 of the intermediate wires F2 of the intermediate layer C2. Here, the sum SI2 = 7 x 0.075 = 0.52 mm, a value strictly greater than d2 = 0.26 mm.

[0206] The outer layer C3 of each inner strand TI is desaturated and completely unsaturated. The inter-wire distance I3 of the outer layer C3 separating on average the N outer wires is advantageously greater than or equal to 5 µm, preferably greater than or equal to 15 µm, more preferably greater than or equal to 35 µm and even more preferably to 50 µm and in this embodiment, the inter-wire distance I2 is very preferably greater than or equal to 60 µm and here equal to 71 µm. The sum SI3 of the inter-wire distances I3 of the outer layer C3 is greater than the diameter d3 of the outer wires F3 of the outer layer C3. Here, the sum SI3 = 12 x 0.071 = 0.85 mm, a value strictly greater than d3 = 0.26 mm.

[0207] Each inner, intermediate and outer wire of each inner strand TI has a diameter d1, d2 and d3 respectively. Each diameter of the inner wires d1, intermediate d2 and outer d3 of each inner strand TI ranges from 0.15 mm to 0.60 mm, preferably from 0.20 mm to 0.50 mm, more preferably from 0.22 mm to 0.40 mm and even more preferably from 0.24 mm to 0.35 mm.

[0208] The inner wire F1 of each inner strand TI has a diameter d1 greater than or equal to the diameter d2 of each intermediate wire F2 of each inner strand TI and very preferably 1≤d1 / d2≤1.10. The inner wire F1 of each inner strand TI has a diameter d1 greater than or equal to the diameter d3 of each outer wire F3 of each inner strand TI and very preferably 1≤d1 / d3≤1.10. Each diameter d2 of each intermediate wire F2 of each inner strand TI and each diameter d3 of each outer wire F3 of each inner strand TI are such that d2=d3.

[0209] In this case, d1=d2=d3 and d1=d2=d3=0.26 mm.

[0210] Each outer wire F3 of each inner strand TI has a diameter d3 greater than or equal to the diameter d3' of each outer wire F3 of each outer strand TE. Here d3=0.26 mm = d3'=0.26 mm

[0211] Each wire has a breaking strength, denoted Rm, such that 2500 ≤ Rm ≤ 3100 MPa. The steel of these wires is said to be of SHT (“Super High Tensile”) grade. Other wires may be used, for example lower grade wires, for example NT (“Normal Tensile”) or HT (“High Tensile”) grade, as well as higher grade wires, for example UT (“Ultra Tensile”) or MT (“Mega Tensile”) grade. METHOD FOR MANUFACTURING THE CABLE ACCORDING TO THE INVENTION

[0212] The cable according to the invention is manufactured using a method comprising steps well known to those skilled in the art.

[0213] Each internal strand previously described is manufactured according to known processes comprising the following steps, preferably carried out in line and continuously: firstly, a first assembly step by cabling the Q internal wires F1 of the internal layer C1 at pitch p1 and in the Z direction to form the internal layer C1 at a first assembly point; followed by a second assembly step by cabling or twisting the M intermediate wires F2 around the Q internal wires F1 of the internal layer C1 at pitch p2 and in the Z direction to form the intermediate layer C2 at a second assembly point; followed by a third assembly step by cabling or twisting the N external wires F3 around the M intermediate wires F2 of the intermediate layer C2 at pitch p3 and in the Z direction to form the external layer C3 and each internal strand TI at a third assembly point; preferably a final twist balancing step.

[0214] In a manufacturing stage of the external strands using the following stages preferably operated in line and continuously: firstly, in the case where Q'>1, a first assembly step by wiring the Q internal wires F1 of the internal layer C1 at pitch p1 and in the Z direction to form the internal layer C1 at a first assembly point; in the embodiments where Q'=1, the first assembly step is avoided; followed by a second assembly step by wiring the M' intermediate wires F2' around the Q' internal wires F1' of the internal layer C1' at pitch p2' and in the Z direction to form the intermediate layer C2' at a first assembly point; followed by a third assembly step by wiring the N' external wires F3' around the M' intermediate wires F2' of the intermediate layer C2' at pitch p3' and in the Z direction to form the external layer C3' and each external strand TE at a second assembly point; preferably a final twist balancing step.

[0215] By "torsion balancing" is meant here, in a manner well known to those skilled in the art, the cancellation of residual torsional torques (or elastic return of torsion) exerted on each wire of the strand, in the intermediate layer as in the external layer.

[0216] After this final twist balancing step, the strand manufacturing is complete. Each strand is wound onto one or more receiving reels for storage, before the subsequent operation of assembling the individual strands by cabling to obtain the multi-strand cable.

[0217] In a manufacturing step of the inner layer CI, the K inner strands TI are assembled by wiring at pitch pi and in the Z direction to form the inner layer CI at a first assembly point.

[0218] Then, in a subsequent manufacturing step, the L external strands TE are assembled by wiring around the internal layer CI at pitch pe and in the Z direction to form the assembly of the layers CI and CE. Optionally, in a final assembly step, the hoop F is wound at pitch pf in the S direction around the previously obtained assembly.

[0219] The cable is then incorporated by calendering into composite fabrics formed from a known composition based on natural rubber and carbon black as a reinforcing filler, conventionally used for the manufacture of crown reinforcements of radial tires. This composition essentially comprises, in addition to the elastomer and the reinforcing filler (carbon black), an antioxidant, stearic acid, an extender oil, cobalt naphthenate as an adhesion promoter, and finally a vulcanization system (sulfur, accelerator, ZnO).

[0220] The composite fabrics reinforced by these cables comprise an elastomeric composition matrix formed by two thin layers of elastomeric composition which are superimposed on either side of the cables and which respectively have a thickness of between 1 and 4 mm inclusive. The calendering pitch (cable laying pitch in the elastomeric composition fabric) ranges from 4 mm to 8 mm.

[0221] These composite fabrics are then used as a working ply in the crown reinforcement during the tire manufacturing process, the steps of which are otherwise known to those skilled in the art. CABLE ACCORDING TO A SECOND EMBODIMENT OF THE INVENTION

[0222] It has been represented on the figure 4 a 50' cable according to a second embodiment of the invention. Elements similar to the first embodiment are designated by identical references.

[0223] Unlike the first embodiment described above, the cable 50' according to the second embodiment is such that K=2 and L=8. CABLE ACCORDING TO A THIRD EMBODIMENT OF THE INVENTION

[0224] It has been represented on the Figure 5 a 50" cable according to a third embodiment of the invention. Elements similar to the first embodiment are designated by identical references.

[0225] Unlike the first embodiment of the cable 50 described previously, the cable 50" according to the third embodiment is such that K=4 and L=10.

[0226] Table A below summarizes the characteristics for the different 50, 50' and 50" cables. CABLES ACCORDING TO THE FOURTH TO FIFTEENTH MODES OF EMBODIMENT OF THE INVENTION

[0227] It has been represented on the figures 6 to 17the cables 51, 51', 51", 52, 52', 52", 60, 60', 60", 61, 61' and 61" according to the fourth to fifteenth embodiments of the invention.

[0228] Tables B and C below summarize the characteristics of the different cables 51, 51', 51", 52, 52', 52", 60, 60', 60", 61, 61' and 61" according to the fourth to fifteenth embodiments of the invention. COMPARATIVE TESTS Indicator of penetrability of strands by an elastomeric composition

[0229] In the following tests, the ability of a strand to be penetrable by an elastomeric composition was determined by simulating the size of the radial passage windows formed by two adjacent wires F2 of the intermediate layer C2 and by two adjacent wires F3 of the outer layer C3. Such windows are illustrated in figure 18on which a schematic view of each internal strand is shown along its main axis P and on the figure 19 which represents the radial passage window S defined previously.

[0230] Such a strand penetrability indicator is an image of the strand's impermeability to air. Indeed, the larger the size of the windows, the higher the penetrability indicator, the more the elastomer composition is likely to penetrate into the strand and the more the strand is impermeable to air. Permeability could also be determined by the permeability test to determine the longitudinal air permeability of tested strands or cables, by measuring the volume of air passing through a test piece under constant pressure for a given time. The principle of such a test, well known to those skilled in the art, is to demonstrate the effectiveness of the treatment of a strand or cable to make it impermeable to air; it has been described for example in the ASTM D2692-98 standard. Such a test is carried out on strands or cables from manufacturing and not aged.The raw strands or cables are first coated from the outside with an elastomeric composition known as a coating. To do this, a series of 10 strands or 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 elastomeric composition in the raw state, each skim having a thickness of 5 mm; the whole is then blocked in a mold, each of the strands or cables being maintained under sufficient tension (for example 3 daN) to guarantee its straightness when placed in the mold, using clamping modules; then vulcanization (baking) is carried out for approximately 10 to 12 hours at a temperature of approximately 120°C and under a pressure of 15 bar (rectangular piston of 80 x 200 mm). After which, the assembly is removed from the mold and 10 specimens of strands or cables thus coated are cut into parallelepipeds measuring 7x7x60 mm for characterization.The elastomeric coating composition used is a conventional diene elastomer(s) composition for tires, based on natural rubber (peptized) and carbon black N330 (65 pce), further comprising the following usual additives: sulfur (7 pce), sulfenamide accelerator (1 pce), ZnO (8 pce), stearic acid (0.7 pce), antioxidant (1.5 pce), cobalt naphthenate (1.5 pce) (pce meaning parts by weight per hundred parts of elastomer); the E10 modulus of the elastomeric coating composition is approximately 10 MPa. The test is carried out on a 6 cm length of strand or cable, therefore coated by its surrounding elastomeric composition (or elastomeric coating composition) in the cooked state, in the following manner: air is sent to the inlet of the strand or cable, under a pressure of 1 bar, and the volume of air at the outlet is measured, using a flow meter (calibrated for example from 0 to 500 cm 3 < / min).During the measurement, the strand or cable sample is blocked in a compressed airtight seal (e.g. a dense foam or rubber seal) in such a way that only the quantity of air passing through the strand or cable from one end to the other, along its longitudinal axis, is taken into account by the measurement; the airtightness of the airtight seal itself is checked beforehand using a specimen of solid elastomeric composition, i.e. without strand or cable. The average air flow rate measured (average over the 10 specimens) is lower the higher the longitudinal impermeability of the strand or cable. Since the measurement is made with an accuracy of ± 0.2 cm3 / min, measured values less than or equal to 0.2 cm3 / min are considered zero; they correspond to a strand or cable that can be described as airtight (totally airtight) along its axis (i.e., in its longitudinal direction).

[0231] However, for the sake of speed in evaluating the strands, the inventors favored the simulation and calculation of S windows over the permeability test. Evaluation of the penetrability indicator of the external strands as a function of the pitch p3 of the cable 50

[0232] Different internal strands similar to the internal strand of cables 50, 51 and 52 according to the invention were simulated by varying the value of p2 for different values of p3, all other structural characteristics of the cable remaining unchanged from the previous description.

[0233] The results of these simulations are gathered in the various tables 50.1 to 52.6 in base 100 in relation to a control strand such that (p3-p2) / p3=0.31 for Q=2, (p3-p2) / p3=0.33 for Q=3 and (p3-p2) / p3=0.25 for Q=4. Thus for a window size value St for the tested strand and a window size value S0 for the control strand, the penetrability indicator is equal to St*100 / S0. Thus, a result greater than 100 means that the tested strand has a greater penetrability than the corresponding control strand. It is estimated that the window size is significantly higher when the penetrability indicator is greater than or equal to 120, i.e. the window size of the tested strand is 20% greater than that of the control strand.

[0234] Each table 50.1 to 52.6 corresponds respectively to a step p3 equal to 12, 14, 16, 18, 20 and 23 mm.

[0235] It is noted that, although the inter-wire distance I2 increases when p2 increases, the maximum value of the radial passage windows is obtained for values of I2 which are not necessarily the highest. Thus, before the invention was made, the person skilled in the art, starting from the assumption that the smaller I2, the less penetrable the strand was, could hardly predict maximum penetrability for values of p2 giving relatively low values of I2.

[0236] In the range of the ratio (p3-p2) / p3 from 0.33 to 0.45 in the case where Q=2, from 0.35 to 0.42 in the case where Q=3 and from 0.28 to 0.43 in the case where Q=4, and for each value of p3 tested, the value of the penetrability indicator is significantly higher than that obtained for the corresponding control strand. Ratios lower than 0.36 (not included) are not part of the subject of the protection of the invention. Evaluation of the penetrability indicator of the internal strands of 50', 50", 51', 51", 52', 52", 60, 60', 60", 61, 61' and 61" cables

[0237] In a manner analogous to cables 50, 51 and 52, different external strands of cables 60 and 61 were simulated according to the different embodiments of the invention by varying the value of p2 while fixing the value of p3 to that described above, all the other structural characteristics of each cable remaining unchanged compared to the previous description.

[0238] The external strands of the 50', 50", 51', 51", 52' and 52" cables being identical respectively to those of the 50 cables for the 50' and 50" cables, 51 for the 51' and 51" cables and 52 for the 52' and 52" cables, the conclusion remains the same, i.e. the interval of the ratio (p3'-p2') / p3' ranging from 0.33 to 0.45 in the case where Q'=2, ranging from 0.35 to 0.42 in the case where Q'=3 and ranging from 0.28 to 0.43 in the case where Q'=4.

[0239] The results of these simulations are gathered in the different tables 60 and 61 in base 100 in relation to a control strand such that (p3-p2) / p3=0.31 for Q=2 and (p3-p2) / p3=0.33 for Q=3. Thus for a window size value St for the tested strand and a window size value S0 for the control strand, the penetrability indicator is equal to St*100 / S0. Thus, a result greater than 100 means that the tested strand has a greater penetrability than the corresponding control strand. It is estimated that the window size is significantly higher when the penetrability indicator is greater than or equal to 120, i.e. the window size of the tested strand is 20% greater than that of the control strand.

[0240] It is noted that, although the inter-wire distance I2 increases when p2 increases, the maximum value of the size of the radial passage windows is obtained for values of I2 that are not necessarily the highest. Thus, before the invention was made, the person skilled in the art, starting from the assumption that the smaller I2, the less penetrable the strand was, could hardly predict maximum penetrability for values of p2 giving relatively low values of I2.

[0241] In the range of the ratio (p3-p2) / p3 from 0.33 to 0.45 in the case where Q=2, from 0.35 to 0.42 in the case where Q=3 and from 0.28 to 0.43 in the case where Q=4, and for each value of p3 tested, the value of the penetrability indicator is significantly higher than that obtained for the corresponding control strand. Ratios lower than 0.36 (not included) are not part of the subject of the protection of the invention.

[0242] Tables 60 and 61 show that, for various cable constructions, the penetration of the elastomeric composition into the outer strands, and therefore the accessibility of each inner strand by this elastomeric composition, is significantly improved for a ratio (p3-p) / p3 ranging from 0.33 to 0.45 in the case where Q=2, ranging from 0.35 to 0.42 in the case where Q=3, and ranging from 0.28 to 0.43 in the case where Q=4 compared to the control cables for which (p3-p2) / p3=0.31 for Q=2, (p3-p2) / p3=0.33, for Q=3 and (p3-p2) / p3=0.25 in the case where Q=4. Ratios lower than 0.36 (not included) are not part of the subject of the protection of the invention.

[0243] Of course, the invention is not limited to the embodiments described above.

[0244] For reasons of industrial feasibility, cost and overall performance, it is preferred to implement the invention with linear wires, i.e. straight, and of conventional circular cross-section.

[0245] It is also possible to combine the characteristics of the different embodiments described or envisaged above, provided that they are compatible with each other.

Claims

1. Two-layer multi-strand cord (50), comprises: - an internal layer (CI) of the cord made up of K>1 internal strands (TI) wound in a helix, each internal strand (TI) being a three-layer (C1, C2, C3) strand and comprising: • an internal layer (C1) made up of Q=2, 3 or 4 internal threads (F1) wound with a pitch p1, the internal layer (C1) being wound in an internal-layer (C1) direction of each internal strand (TI), • an intermediate layer (C2) made up of M intermediate threads (F2), wound around the internal layer (C1) with a pitch p2, the intermediate layer (C2) being wound in an intermediate-layer (C2) direction of each internal strand (TI), and • an external layer (C3) made up of N external threads (F3) wound around the intermediate layer (C2) with a pitch p3, - an external layer (CE) of the cord made up of L>1 external strands (TE) wound around the internal layer (CI) of the cord, each external strand (TE) being an at least two-layer (C1', C3') strand and comprising: • an internal layer (C1') made up of Q' internal thread(s) (F1'), and • an external layer (C3') made up of N' external threads (F3') wound around the internal layer (C1'), wherein: - p1 is different from p2 and / or the internal-layer (C1) direction of each internal strand (TI) is different from the intermediate-layer (C2) direction of each internal strand (TI); - the intermediate layer (C2) of each internal strand (TI) is desaturated; - the external layer (C3) of each internal strand (TI) is desaturated; and characterized in that: - the pitches p2 and p3 satisfy the relationship: - 0.36 ≤ (p3-p2) / p3≤ 0.45 in instances in which Q=2, - 0.36 ≤ (p3-p2) / p3≤ 0.42 in instances in which Q=3, - 0.36 ≤ (p3-p2) / p3 ≤ 0.43 in instances in which Q=4 and the mean inter-strand distance E separating two adjacent external strands (TE) is greater than or equal to 150 µm.

2. Cord (50) according to the preceding claim, in which the mean inter-strand distance E separating two adjacent external strands is greater than or equal to 200 µm.

3. Cord (50) according to either one of the preceding claims, in which: - 0.38 ≤ (p3-p2) / p3 in instances in which Q=2, - 0.38 ≤ (p3-p2) / p3 in instances in which Q=3.

4. Cord (50) according to any one of the preceding claims, in which: - (p3-p2) / p3 ≤ 0.42 and preferably (p3-p2) / p3 ≤ 0.40 in instances in which Q=2, - (p3-p2) / p3 ≤ 0.40 in instances in which Q=3, - (p3-p2) / p3 ≤ 0.40 and preferably (p3-p2) / p3 ≤ 0.38 in instances in which Q=4.

5. Cord (50) according to any one of the preceding claims, in which the pitch p1 is such that 3 mm ≤ p1 ≤ 16 mm, for preference 4 mm ≤ p1 ≤ 13 mm and more preferably 5 mm ≤ p1 ≤ 10 mm.

6. Cord (50) according to any one of the preceding claims, in which the pitch p2 is such that 8 mm ≤ p2 ≤ 20 mm, for preference 9 mm ≤ p2 ≤ 18 mm and more preferably 10 mm ≤ p2 ≤ 16 mm.

7. Cord (50) according to any one of the preceding claims, in which the pitch p3 is such that 10 mm ≤ p3 ≤ 40 mm, for preference 12 mm ≤ p3 ≤ 30 mm and more preferably 15 mm ≤ p3 ≤ 25 mm.

8. Cord (50) according to any one of the preceding claims, in which K=2, 3 or 4, and preferably K=3 or 4.

9. Cord (50) according to any one of the preceding claims, in which L=7, 8, 9 or 10, preferably L=8, 9 or 10 and more preferably L=8 or 9.

10. Cord (50) according to any one of the preceding claims, in which the internal layer (CI) of the cord is wound in a helix in a cord internal-layer direction with a pitch pi, the external layer (CE) of the cord is wound in a helix in a cord external-layer direction with a pitch pe, and the cord satisfies one and / or the other of the following features: - the cord internal-layer direction is different from the cord external-layer direction, - pi is different from pe.

11. Cord (50) according to any one of the preceding claims, in which M=7, 8, 9 or 10 and N=12, 13, 14 or 15.

12. Cord (50) according to any one of the preceding claims, in which the sum SI2 of the inter-thread distances (I2) of the intermediate layer (C2) of each internal strand (TI) is such that SI2 < d3 where d3 is the diameter of each external thread (F3) of each internal strand (TI), preferably SI2 ≤ 0.8 x d3.

13. Cord (50) according to any one of the preceding claims, in which the external layer (C3) of each internal strand (TI) is completely unsaturated.

14. Cord (50) according to any one of the preceding claims, in which the external layer (C3') of each external strand (TE) is desaturated, preferably completely unsaturated.

15. Tyre (10), characterized in that it comprises the cord (50) according to any one of the preceding claims