Single-layer extracted cable with optimized wire distribution

Abstract

The invention relates to an extracted cable (50) from a polymer matrix, the extracted cable (50) comprising a single layer (52) consisting of N metal wire elements (54) wound in a helix, each metal wire element (54) of the layer (52) describing, when the cable (50) extends in a substantially rectilinear direction, a helix-shaped trajectory around a main axis (A) substantially parallel to the substantially rectilinear direction, such that, in a section plane substantially perpendicular to the main axis (A), the distance between the center of each metal wire element (54) of the layer (52) and the main axis (A) is equal to half the helix diameter Dh and is substantially constant and equal for all the metal wire elements (54) of the layer (52), the metal wire elements (54) defining an internal arch (58) of the cable of diameter Dv,each metal wire element (54) having a diameter Df and a helix radius of curvature Rf defined by Rf=P / (π x Sin(2α)) with P the pitch of each metal wire element expressed in millimeters and α the helix angle of each metal wire element (54),in which, Dh, D, Dv, Df and Rf being expressed in millimeters:9 ≤ Rf / Df ≤ 30, and1.30 ≤ Dv / Df ≤ 4.5; andthe space between the wires is the relative clearance defined by the relative clearance Jr =(π x Dh) / N x (Dh x Sin(π / N) – (Df / Cos(α x π / 180))), with α being the helix angle, expressed in degrees, of each metal wire (54). The maximum space available between the extreme wires Jr max = N x Jr is such that 0.35 x π x Dh ≤ Jr max ≤ 0.60 x π x Dh. Figure for abbreviation: Fig.4,

Description

Title of the invention: Single-layer extracted cable with optimized wire distribution

[0001] The present invention relates to metal cables which can be used for reinforcing articles such as vehicle tires and preferably in a tire for a civil engineering vehicle. By tire is meant a bandage intended to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure higher than atmospheric pressure. A tire according to the invention has a structure of substantially toroidal shape.

[0002] Known from the state of the art is a cable with a structure of n + N metal wires with a diameter of 0.30 mm, with n being a PVA textile core by the application of a hot water jet device which dissolves to obtain a cable with a structure of 4 wires with a diameter of 0.30 mm, at least 2 wires of which are spaced apart (figure 11 and the cables described on page 8 of WO2021124138). Such aeration via a system for passing the cable over a plurality of cylinders having a reduced diameter results in better penetration of the cable and also modifies the rigidity of the cable. Such a cable is in particular intended to be used in tires, for example tires for motorcycle-type vehicles.

[0003] In addition to requiring a step of dissolving the textile core by water jet, this cable has risks of undergoing corrosion and the complexities of the characteristics of the core which must be soluble in water and in addition have mechanical properties in terms of rigidity and resistance is necessary for the implementation of the cable.

[0004] Also known from the state of the art and in particular from document WO2016 / 131862 is a cable comprising a single layer of N=4 strands wound in a helix at a pitch p3=20 mm. Each strand comprises, on the one hand, an inner layer of M=3 inner wires wound in a helix at a pitch p1=6.7 mm and an outer layer of P=8 outer wires wound in a helix around the inner layer at a pitch p2=10 mm. Each inner and outer wire has a diameter equal to 0.35 mm and an elongation at break of 3.3%.

[0005] Such a cable is notably used in a tire for a civil engineering vehicle comprising a protective reinforcement. This protective reinforcement comprises one or more protective plies comprising several cables as described above. The disadvantage of this type of cable is that its structural elongation can be improved to improve its deformability for its resistance to attacks.

[0006] The invention aims to provide extracted cables comprising a single layer of N metallic wire elements wound in a helix and making it possible to limit the rigidity of the cable under low elongation.

[0007] For this purpose, the invention relates to a cable extracted from a polymer matrix, the extracted cable comprising a single layer consisting of N metal wire elements wound in a helix, each metal wire element of the layer describing, when the cable extends in a substantially rectilinear direction, a helix-shaped trajectory around a main axis (A) substantially parallel to the substantially rectilinear direction, so that, in a section plane substantially perpendicular to the main axis (A), the distance between the center of each metal wire element of the layer and the main axis (A) is equal to half the helix diameter Dh and is substantially constant and equal for all the metal wire elements of the layer, the metal wire elements defining an internal arch of the cable of diameter Dv,each metallic wire element having a diameter Df and a helix curvature radius Rf defined by Rf=P / (ir x Sin(2a)) with P the pitch of each metallic wire element expressed in millimeters and a the helix angle of each metallic wire element (54), in which, Dh, D, Dv, Df and Rf being expressed in millimeters: 9 <Rf / Df <30, et , 1.30 < Dv / Df < 4.5; and the space between the wires is the relative clearance defined by the relative clearance Jr = (ji x Dh) / N x (Dh x Sin(ir / N) - (Df / Cos(ax jt / 1 80))), with a being the helix angle, expressed in degrees, of each metal wire (54); in which the maximum space available between the extreme wires Jr max = N x Jr is such that 0.35 x ir x Dh < Jr max < 0.60 x ir x Dh.

[0008] Thanks to this maximum space available between the extreme wires Jr max, the cable according to the invention makes it possible to reduce perforations and therefore to extend the life of the tire. Indeed, the original inventors discovered that a less rigid cable than that of the state of the art is more efficient against obstacles. The inventors found that it was more effective to fit the obstacle using a cable having less rigidity rather than trying to stiffen and reinforce the cables as much as possible to oppose the deformations imposed by the obstacles as is generally taught in the state of the art. By fitting the obstacles, the force opposing the obstacles is reduced and therefore the risk of perforating the tire.

[0009] The cable extracted according to the invention has an optimized distribution of the wires, the advantage of which is to limit the rigidity of the cable under low elongation, which makes it possible to maximize the breaking energy.

[0010] The values ​​of the characteristics Df, Dv and Rf as well as the other characteristics described below are measured on or determined from the cables extracted from an elastomeric matrix, for example from a tire, and having then undergone a cleaning step during which any elastomeric matrix, in particular any material present inside the cable, is removed from the cable. To guarantee an original condition, the adhesive interface between each metallic wire element and the elastomeric matrix must be removed, for example by an electrochemical process in a sodium carbonate bath. The effects associated with the shaping step of the tire manufacturing process described below, in particular the elongation of the cables, are cancelled out by the extraction of the ply and the cable which, during extraction, substantially regain their characteristics from before the shaping step.

[0011] The cable according to the invention comprises a single layer of helically wound metal wire elements. In other words, the cable according to the invention comprises a single, not two, nor more than two layers of helically wound metal wire elements. The layer is made up of metal wire elements, i.e. several metal wire elements, not a single metal wire element. In one embodiment of the cable, for example when the cable is derived from its manufacturing process, the cable according to the invention is made up of the layer of wound metal wire elements.

[0012] The cable according to the invention is single helix. By definition, a single helix cable is a cable in which the axis of each metal wire element of the layer describes a single helix, unlike a double helix cable in which the axis of each metal wire element describes a first helix around the axis of the cable and a second helix around a helix described by the axis of the cable. In other words, when the cable extends in a substantially rectilinear direction, the cable comprises a single layer of metal wire elements wound together in a helix, each metal wire element of the layer describing a helix-shaped path around the substantially rectilinear direction so that the distance between the center of each metal wire element of the layer and the axis of the substantially rectilinear direction is substantially constant and equal for all the metal wire elements of the layer.In contrast, when a double helix cable extends in a substantially straight direction, the distance between the center of each wire element in the layer and the substantially straight direction is different for all wire elements in the layer.

[0013] The cable according to the invention is devoid of a central metal core. It is also referred to as an IxN structure cable in which N is the number of metal wire elements or even an open-cord cable. In the cable according to the invention defined above, the internal vault is empty and therefore devoid of any filling material, in particular devoid of any com elastomeric position. We then speak of a cable without filling material.

[0014] The arch of the cable according to the invention is delimited by the metallic wire elements and corresponds to the volume delimited by a theoretical circle, on the one hand, radially inside each metallic wire element and, on the other hand, tangent to each metallic wire element.

[0015] By wire element is meant an element extending longitudinally along a main axis and having a section perpendicular to the main axis whose largest dimension G is relatively small compared to the dimension L along the main axis. By relatively small is meant that L / G is greater than or equal to 100, preferably greater than or equal to 1000. This definition covers both wire elements of circular section and wire elements of non-circular section, for example of polygonal or oblong section. Very preferably, each metal wire element has a circular section.

[0016] By definition, the term metallic means a wire element consisting mainly (i.e. for more than 50% of its mass) or entirely (for 100% of its mass) of a metallic material. Each metallic wire element is preferably made of steel, more preferably of pearlitic or ferrito-pearlitic carbon steel, commonly called carbon steel by those skilled in the art, or even of stainless steel (by definition, steel comprising at least 10.5% chromium).

[0017] As a reminder, a force-elongation curve comprises, moving towards increasing elongations, a structural part, an elastic part and a plastic part. The structural part corresponds to a structural elongation of the cable resulting from the bringing together of the different metallic reinforcing elements constituting the cable. In certain embodiments, the layer of N metallic reinforcing elements deconstructs at the end of the structural part, due to the relatively large relative radial clearance Jrmax, causing a punctual drop in the modulus of the cable. The elastic part corresponds to an elastic elongation resulting from the construction of the cable, in particular the angles of the different layers and the diameters of the wires. The plastic part corresponds to the plastic elongation resulting from the plasticity (irreversible deformation beyond the elastic limit) of one or more metallic reinforcing elements of the reinforced product.

[0018] The relative radial clearance Jr is representative of the distance separating each pair of adjacent metal wire elements reduced to the length available for positioning the metal wire elements on the layer. Thus, the higher Jr, the greater the space separating two adjacent metal wire elements compared to the maximum number of metal wire elements that the layer could accommodate. Conversely, the smaller Jr, the greater the space separating two metal wire elements adjacent is small compared to the maximum number of metallic wire elements that the layer could accommodate. In the interval according to the invention, Jrmax makes it possible to limit the rigidity of the cable under low elongation and on the other hand to maximize the elongation at break.

[0019] The helix angle a is a quantity well known to those skilled in the art and can be determined by the following iterative calculation comprising 3 iterations and in which the index i indicates the number of iteration 1, 2 or 3. Knowing the structural elongation As expressed in %, the helix angle a(i) is such that a(i)=Arcos [ (100 / (100+As) x Cos [ Arctan ( (ji x Df) / (P x Cos(a(i-1)) x Sin(ir / N)) ] ], formula in which P is the pitch expressed in millimeters at which each metal wire element is wound, N is the number of metal wire elements in the layer, Df is the diameter of each metal wire element expressed in millimeters, Arcos, Cos, Arctan and Sin denoting respectively the arcosine, cosine, arctangent and sine functions. For the first iteration, i.e. for the calculation of a(l), we take a(0)=0. At the third iteration, we obtain a(3)=a with at least one significant figure after the decimal point when a is expressed in degrees.

[0020] The helix diameter Dh, expressed in millimeters, is calculated according to the relation Dh=P x Tan(a) / ir in which P is the pitch expressed in millimeters at which each metal wire element is wound, a is the helix angle of each metal wire element determined above and Tan the tangent function. The helix diameter Dh corresponds to the diameter of the theoretical circle passing through the centers of the metal wire elements of the layer in a plane perpendicular to the axis of the cable.

[0021] The arch diameter Dv, expressed in millimeters, is calculated according to the relation Dv=Dh-Df in which Df is the diameter of each metallic wire element and Dh the helix diameter, both expressed in millimeters.

[0022] The radius of curvature Rf, expressed in millimeters, is calculated according to the relation Rf=P / (ir x Sin(2a)) in which P is the pitch expressed in millimeters, a is the helix angle of each metallic wire element and Sin the sine function.

[0023] It is recalled that the pitch at which each metallic wire element is wound is the length traveled by this wire element, measured parallel to the axis of the cable in which it is located, at the end of which the wire element having this pitch makes a complete turn around said axis of the cable.

[0024] The optional features described below may be combined with each other to the extent that such combinations are technically compatible.

[0025] In an advantageous embodiment, all the metallic wire elements have the same diameter Df.

[0026] The cable according to the invention is manufactured in accordance with a method and by implementing implements an installation described in documents WO2016083265 and WO2016083267. Such a method implementing a fractionation step is to be distinguished from a conventional assembly method comprising a single assembly step in which the metal wire elements are wound in a helix, the assembly step being preceded by a step of preforming the metal wire elements in order in particular to increase the value of the structural elongation. Such methods and installations are described in documents EP0548539, EP1000194, EP0622489 or EP0143767. During these methods, in order to obtain the highest possible structural elongation, the metal monofilaments are individually preformed.However, this step of individual preforming of the metal monofilaments, which requires a special installation, on the one hand, makes the process relatively unproductive compared to a process without a preforming step without however allowing high structural elongations to be achieved and, on the other hand, alters the metal monofilaments thus preformed due to friction with the preforming tools. Such an alteration creates incipient breaks on the surface of the metal monofilaments and is therefore detrimental to the endurance of the metal monofilaments, in particular to their endurance in extension and compression. The absence or presence of such preforming marks can be observed under an electron microscope at the end of the manufacturing process, or more simply, by knowing the manufacturing process of the cable.

[0027] Preferably, the polymeric matrix is ​​an elastomeric matrix.

[0028] The polymeric matrix, preferably elastomeric, is based on a polymeric composition, preferably elastomeric.

[0029] By polymeric matrix is ​​meant a matrix comprising at least one polymer. The polymeric matrix is ​​thus based on a polymeric composition.

[0030] By elastomeric matrix is ​​meant a matrix comprising at least one elastomer. The preferred elastomeric matrix is ​​thus based on the elastomeric composition.

[0031] By the expression "based on", it is meant that the composition comprises the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacture of the composition; the composition thus being able to be in the totally or partially crosslinked state or in the non-crosslinked state.

[0032] By 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.

[0033] By elastomeric composition is meant that the composition comprises at least one elastomer and at least one other component. Preferably, the composition comprising at least one elastomer and at least one other component comprises an elastomer, a crosslinking system and a filler. The compositions which can be used for these plies are conventional compositions for calendering reinforcing filamentary elements and comprise a diene elastomer, for example natural rubber, a reinforcing filler, for example carbon black and / or silica, a crosslinking system, for example a vulcanization system, preferably comprising sulfur, stearic acid and zinc oxide, and optionally a vulcanization accelerator and / or retarder and / or various additives. The adhesion between the metal wires and the matrix in which they are embedded is ensured for example by a metal coating, for example a layer of brass.

[0034] The values ​​of the characteristics described in the present application for the extracted cable are measured on or determined from cables extracted from a polymeric matrix, in particular an elastomeric one, for example from a tire. Thus, for example on a tire, the strip of material is removed radially outside the cable to be extracted so as to see the cable to be extracted radially flush with the polymeric matrix. This removal can be done by peeling using pliers and knives or by planing. Then, the end of the cable to be extracted is released using a knife. Then, the cable is pulled so as to extract it from the matrix by applying a relatively small angle so as not to plasticize the cable to be extracted.The extracted cables are then carefully cleaned, for example using a knife, so as to detach the remains of polymer matrix locally attached to the cable and taking care not to damage the surface of the metal wires.

[0035] Preferably, 0.40 x ir x Dh < Jr max < 0.55 x ir x Dh.

[0036] Advantageously, the structural elongation As is such that As > 4.0% determined by the ASTM D2969-04 standard of 2014.

[0037] The structural elongation As, a quantity well known to those skilled in the art, is determined for example by applying the ASTM D2969-04 standard of 2014 to a cable tested so as to obtain a force-elongation curve. The As is deduced on the curve obtained as the elongation, in %, corresponding to the maximum slope of the force-elongation curve, that is to say that the As obtained by the intersection of the maximum slope of the curve with the abscissa axis. As a reminder, a force-elongation curve comprises, moving towards increasing elongations, a structural part, an elastic part and a plastic part. The structural part corresponds to the structural elongation As resulting from the aeration of the cable, that is to say the vacant space between the different metallic wire elements constituting the cable. The elastic part corresponds to an elastic elongation resulting from the construction of the cable, including the angles of the different layers, the diameters and the nature of the wires. The plastic part corresponds to the plastic elongation resulting from the plasticity (irreversible deformation beyond the elastic limit) of one or more metallic wire elements.

[0038] Advantageously, the total elongation At is such that At > 10.0% determined by the ASTM D2969-04 standard of 2014.

[0039] Advantageously, 9 < Rf / Df < 17.

[0040] Preferably, 1.30 < Dv / Df < 4.0, preferably 1.30 < Dv / Df < 3.60.

[0041] Advantageously, the helix radius of curvature Rf is such that 2 mm < Rf < 7 mm, preferably 2 mm < Rf < 5 mm and more preferably 3 mm < Rf < 5 mm.

[0042] In one embodiment of a cable intended for reinforcing a tire for passenger vehicles, but also for two-wheeled vehicles such as motorcycles, and preferably for passenger vehicles, there is 2 mm < Rf < 5 mm and preferably 3 mm < Rf < 5 mm.

[0043] In one embodiment of a cable intended for reinforcing a tire for industrial vehicles chosen from vans, "Heavy goods vehicles", for example metro, bus, road transport vehicles (trucks, tractors, trailers), we have 4 mm < Rf < 6 mm and preferably 4 mm < Rf < 5 mm.

[0044] In one embodiment of a cable intended for reinforcing a tire for off-road vehicles, for example agricultural or civil engineering machinery, there is 4 mm < Rf < 7 mm and preferably 4.5 mm < Rf < 6.5 mm.

[0045] Advantageously, the helix diameter Dh of each metallic wire element (54) is such that 0.40 mm < Dh < 2.00 mm, preferably 0.50 mm < Dh < 1.80 mm.

[0046] In one embodiment of a cable intended for reinforcing a tire for industrial vehicles chosen from vans, "Heavy goods vehicles", for example metro, bus, road transport vehicles (trucks, tractors, trailers), there is 0.85 mm < Dh < 1.20 mm and preferably 0.90 mm < Dh <1.15 mm.

[0047] In one embodiment of a cable intended for reinforcing a tire for off-road vehicles, for example agricultural or civil engineering machinery, there is 0.95 mm < Dh < 1.40 mm and preferably 1.00 mm < Dh < 1.35 mm.

[0048] Advantageously, Df is such that 0.10 mm < Df < 0.50 mm, preferably 0.25 mm < Df < 0.45 mm and more preferably 0.25 mm < Df < 0.40 mm.

[0049] In one embodiment of a cable intended for reinforcing a tire for passenger vehicles, but also for two-wheeled vehicles such as motorcycles, and preferably for passenger vehicles, there is 0.20 mm < Df < 0.35 mm and preferably 0.25 mm < Df < 0.33 mm.

[0050] In one embodiment of a cable intended for reinforcing a tire for industrial vehicles chosen from vans, "Heavy goods vehicles", for example metro, bus, road transport vehicles (trucks, tractors, trailers), we have 0.22 mm < Df < 0.40 mm and preferably 0.25 mm < Df < 0.38 mm.

[0051] In one embodiment of a cable intended for reinforcing a tire for off-road vehicles, for example agricultural or civil engineering machinery, there is 0.32 mm < Df < 0.50 mm and preferably 0.35 mm < Df < 0.50 mm.

[0052] Advantageously, Dv is such that Dv > 0.46 mm, preferably 0.46 mm < Dv < 1.50 mm.

[0053] In one embodiment of a cable intended for reinforcing a tire for passenger vehicles, but also for two-wheeled vehicles such as motorcycles, and preferably for passenger vehicles, we have 0.46 mm < Dv < 0.70 mm.

[0054] In one embodiment of a cable intended for reinforcing a tire for industrial vehicles chosen from vans, "Heavy goods vehicles", for example metro, bus, road transport vehicles (trucks, tractors, trailers), we have 0.50 mm < Dv < 0.80 mm.

[0055] In one embodiment of a cable intended for reinforcing a tire for off-road vehicles, for example agricultural or civil engineering machinery, there is 0.55 mm < Dv < 1.00 mm.

[0056] Advantageously, each metallic wire element is wound at a pitch P such that 3 mm < P < 15 mm, preferably 3 mm < P < 12 mm.

[0057] In one embodiment of a cable intended for reinforcing a tire for passenger vehicles, but also for two-wheeled vehicles such as motorcycles, and preferably for passenger vehicles, we have 3 mm < P < 9 mm.

[0058] In one embodiment of a cable intended for reinforcing a tire for industrial vehicles chosen from vans, "Heavy goods vehicles", for example metro, bus, road transport vehicles (trucks, tractors, trailers), we have 7 mm < P < 15 mm.

[0059] In one embodiment of a cable intended for reinforcing a tire for off-road vehicles, for example agricultural or civil engineering machinery, 9 mm < P < 15 mm is present.

[0060] Advantageously, the diameter D is such that D < 2.50 mm, preferably 0.75 mm < D < 2.40 mm and more preferably 1.00 mm < D < 2.00 mm.

[0061] The diameter or apparent diameter, noted D, is measured by means of a thickness comparator whose contact diameter is at least equal to 1.5 times the pitch P of winding of the wire elements (one can cite for example the model JD50 of the KAEFER brand allowing to reach a precision of 1 / 100 of a millimeter, equipped with a type a contact, and having a contact pressure close to 0.6N). The measurement protocol consists of three repetitions of a series of three measurements (carried out perpendi cularly to the axis of the cable and under zero tension) of which the second and third of these measurements are carried out in a direction angularly offset from the previous one by a third of a turn, by the rotation of the measurement direction around the axis of the cable.

[0062] In one embodiment of a cable intended for reinforcing a tire for passenger vehicles, but also for two-wheeled vehicles such as motorcycles, and preferably for passenger vehicles, there is 0.75 mm < D < 1.40 mm and preferably 1.00 mm < D < 1.30 mm.

[0063] In one embodiment of a cable intended for reinforcing a tire for industrial vehicles chosen from vans, "Heavy goods vehicles", for example metro, bus, road transport vehicles (trucks, tractors, trailers), we have 1.15 mm < D < 1.55 mm.

[0064] In one embodiment of a cable intended for reinforcing a tire for off-road vehicles, for example agricultural or civil engineering machinery, 1.5 mm < D < 2 mm is present.

[0065] In one embodiment, each metal wire element comprises a single metal monofilament. Here, each metal wire element is advantageously made of a metal monofilament. In a variant of this embodiment, the metal monofilament is directly coated with a layer of a metal coating comprising copper, zinc, tin, cobalt or an alloy of these metals, for example brass or bronze. In this variant, each metal wire element is then made of the metal monofilament, for example steel, forming a core, directly coated with the layer of metal coating.

[0066] In this embodiment, each elementary metallic monofilament is, as described above, preferably made of steel, and has a mechanical strength ranging from 1000 MPa to 5000 MPa. Such mechanical strengths correspond to the steel grades commonly encountered in the field of tires, namely, the grades NT (Normal Tensile), HT (High Tensile), ST (Super Tensile), SHT (Super High Tensile), UT (Ultra Tensile), UHT (Ultra High Tensile) and MT (Mega Tensile), the use of high mechanical strengths possibly allowing improved reinforcement of the matrix in which the cable is intended to be embedded and a lightening of the matrix thus reinforced.

[0067] Advantageously, the layer being made up of N metallic wire elements wound in a helix, N ranges from 3 to 12.

[0068] Advantageously, the ratio K of the pitch P to the diameter Df of each metallic wire element, P and Df being expressed in millimeters, is such that 19 < K < 44.

[0069] Advantageously, the helix angle a of each metallic wire element (54) is such that 13° < a < 30.

[0070] Advantageously, each metal wire element is free of pre-marks. formation. In other words, the cable is obtained by a process without individual pre-forming steps for each of the metal wire elements.

[0071] As described above, the cable according to the invention is manufactured in accordance with a method and by implementing an installation described in documents WO2016083265 and WO2016083267. This method comprises a step of assembling M metal wire elements together in a layer of the M metal wire elements around a transient core to form a transient assembly, and a step of splitting the transient assembly into at least first and second assemblies of M1 metal wire elements and M2 metal wire elements. At least one of the first and second assemblies then forms the cable according to the invention, i.e. M1=N and / or M2=N.

[0072] Advantageously, in a first embodiment, the step of splitting the transient assembly comprises a step of separating the transient core from the first and second assemblies. In this embodiment, the first assembly consists of M1 metal wire elements wound together and distributed in a single layer around the axis of the first assembly. Similarly, the second assembly of this embodiment consists of M2 metal wire elements wound together and distributed in a single layer around the axis of the second assembly. In other words, in this first embodiment, the transient core comprising at least one wire element, each wire element of the transient core does not belong to the first and second assemblies of M1 metal wire elements and M2 metal wire elements. We therefore have M1+M2=M.

[0073] In a first preferred variant of this first embodiment, during the splitting step, the first assembly is separated from a transient assembly formed by the second assembly and the transient core, then the second assembly and the transient core are separated from each other. In a second variant, during the splitting step, the transient core, the first assembly and the second assembly are simultaneously separated two by two from each other.

[0074] Advantageously, the method comprises a step of recycling the transient core during which: - the transient nucleus is recovered downstream of the fractionation step, and - the transient core recovered previously is introduced upstream of the step assembly.

[0075] In a preferred embodiment, the step of recycling the transient core can be carried out continuously, i.e. in which the transient core leaving the separation step is reintroduced into the assembly step without an intermediate storage step of the transient core. In another embodiment, the step of recycling the transient core is discontinuous, i.e. with a storage step. intermediate of the transient nucleus.

[0076] More preferably, a textile transitional core is used.

[0077] In a second embodiment, the step of splitting the transient assembly comprises a step of splitting the transient core between at least the first and second assemblies. Thus, in this second embodiment, two assemblies of metallic wire elements are obtained, each comprising a layer of P1, P2 metallic wire elements wound together in a helix, and for at least one of the assemblies, a central core comprising or consisting of at least a portion of the transient core around which the metallic wire elements of the layer are wound. In other words, in this second embodiment, the transient core comprising K metallic wire element(s), at least one of the K metallic wire element(s) of the transient core belongs to at least one of the first and second assemblies of M1 metallic wire elements and M2 metallic wire elements.

[0078] Advantageously, during the fractionation step, at least a first part of the transient core is fractionated with first metallic wire elements of the transient assembly so as to form the first assembly.

[0079] Thus, the first assembly comprises a layer of PI metallic wire elements wound together in a helix and a central core comprising or consisting of a first part (K1 wire element(s)) of the K metallic wire elements of the transitional core and around which the PI metallic wire elements are wound together in a helix. We have P1+K1=M1.

[0080] Advantageously, during the fractionation step, at least a second part of the transient core is fractionated with second metallic wire elements of the transient assembly so as to form the second assembly.

[0081] Thus, the second assembly comprises a layer of P2 metallic wire elements wound together in a helix and a central core comprising or constituted by a second part (K2 wire element(s)) of the K wire elements of the transient core and around which the P2 metallic wire elements are wound together in a helix. We have P2+K2=M2.

[0082] Preferably, the first and second assemblies are formed simultaneously.

[0083] Preferably, before the splitting step, the first and second parts of the transient core constitute the transient core. Thus, the first and second parts of the transient core are complementary. We therefore have K1+K2=K. In a variant, we could have K1+K2 <k.

[0084] In a variant, the first assembly comprises a layer of PI metallic wire elements wound together in a helix around a central core comprising or consisting of the transitional core and the second assembly comprises a layer of P2=M2 metallic wire elements wound together in a helix and without a central core.

[0085] In one embodiment, the assembly step is carried out by twisting. In such a case, the metal wire elements undergo both collective twisting and individual twisting around their own axis, which generates an untwisting torque on each of the metal wire elements.

[0086] Preferably, in the case of a twisting assembly step, the method comprises a step of balancing the transient assembly. Thus, the balancing step being carried out on the assembly consisting of the M metallic wire elements and the transient core, the balancing step is implicitly carried out upstream of the fractionation step.

[0087] REINFORCED PRODUCT ACCORDING TO THE INVENTION

[0088] The invention also relates to a reinforced product comprising a polymer matrix and at least one extracted cable as defined above.

[0089] Advantageously, the reinforced product comprises one or more cables according to the invention embedded in the polymer matrix, and in the case of several cables, the cables are arranged side by side in a main direction.

[0090] PNEUMATIC ACCORDING TO THE INVENTION

[0091] The invention also relates to a tire comprising at least one extracted cable as defined above or a reinforced product as defined above.

[0092] Preferably, 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.

[0093] In a preferred embodiment, the crown reinforcement comprises a protective reinforcement and a working reinforcement, the working reinforcement comprising at least one cable as defined above, the protective reinforcement being radially interposed between the tread and the working reinforcement.

[0094] The cable is particularly intended for industrial vehicles chosen from heavy vehicles such as "Heavy Goods Vehicles" - i.e., metro, bus, road transport vehicles (trucks, tractors, trailers), off-road vehicles -, agricultural or civil engineering vehicles, other transport or handling vehicles.

[0095] Preferably, the tire is for a civil engineering type vehicle. Thus, the tire has a dimension in which the diameter, in inches, of the seat of the rim on which the tire is intended to be mounted is greater than or equal to 30 inches.

[0096] The invention also relates to a rubber article comprising an assembly according to the invention, or an impregnated assembly according to the invention. By rubber article outchouc means any type of rubber article such as a ball, a non-pneumatic object such as a non-pneumatic tire, a conveyor belt or a caterpillar.

[0097] The invention will be better understood by reading the examples which follow, given solely as non-limiting examples and made with reference to the drawings in which: - [Fig.l] is a sectional view perpendicular to the circumferential direction of a tire according to the invention; - [Fig.2] is a detailed view of zone II of [Fig.l]; - [Fig.3] is a sectional view of a reinforced product according to the invention; - [Fig.4] is a sectional view perpendicular to its axis of an extracted cable 50 of the invention (assumed to be rectilinear and at rest); - [Fig.5] is a sectional view perpendicular to its axis of a comparative cable C1 (assumed to be rectilinear and at rest) and of the cable 80 according to the invention; and - [Fig.6] represents a photograph of the cable 50 according to the invention. EXAMPLE OF A TIRE ACCORDING TO THE INVENTION

[0098] In Figures 1 and 2, a reference X, Y, Z is shown corresponding to the usual axial (X), radial (Y) and circumferential (Z) orientations of a tire.

[0099] 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.

[0100] Figures 1 and 2 show a tire according to the invention and designated by the general reference P.

[0101] The P tire is for heavy vehicles of the civil engineering type, for example of the “dumper” type. Thus, the P tire has a dimension of type 53 / 80R63.

[0102] The tire P 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.

[0103] The carcass reinforcement 24 comprises at least one carcass ply 30 reinforced by radial carcass cables (not shown). The carcass cables are arranged substantially parallel to each other and extend from one bead 18 to the other so as to form an angle of between 80° and 90° with the circumferential plane. median differential M (plane perpendicular to the axis of rotation of the tire which is located midway between the two beads 18 and passes through the middle of the crown reinforcement 14).

[0104] The tire P also comprises a sealing ply 32 made of an elastomer (commonly called inner rubber) which defines the radially inner face 34 of the tire P and which is intended to protect the carcass ply 30 from the diffusion of air coming from the space inside the tire P.

[0105] The crown reinforcement 14 comprises, radially from the outside towards the inside of the tire P, 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 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.

[0106] The protective reinforcement 36 comprises first and second protective plies 42, 44 comprising protective metal cables, the first ply 42 being arranged radially inside the second ply 44. Optionally, the protective metal cables make 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.

[0107] 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 ply 46, 48 comprises at least one cable 50. Optionally, the working metal cables 50 are crossed from one working ply to the other and make an angle at most equal to 60°, preferably ranging from 15° to 40° with the circumferential direction Z of the tire.

[0108] The additional reinforcement, also called a limiter block, the function of which is to partially absorb the mechanical stresses of inflation, comprises, for example and in a manner known per se, additional metal reinforcing elements, for example as described in FR 2 419 181 or FR 2 419 182 making an angle at most equal to 10°, preferably ranging from 5° to 10° with the circumferential direction Z of the tire P.

[0109] EXAMPLE OF REINFORCED PRODUCT ACCORDING TO THE INVENTION

[0110] [Fig. 3] shows a reinforced product according to the invention and designated by the general reference R. The reinforced product R comprises at least one cable 50, in this case several cables 50, embedded in the polymer matrix Ma.

[0111] In [Fig.3], the polymer matrix Ma is shown, the cables 50 in a X, Y, Z coordinate system in which the Y direction is the radial direction and the X and Z directions are the axial and circumferential directions. In [Fig.3], the reinforced product R comprises several cables 50 arranged side by side along the main direction X and extending parallel to each other within the reinforced product R and collectively embedded in the polymer matrix Ma.

[0112] Here, the polymeric matrix Ma is an elastomeric matrix based on an elastomeric composition.

[0113] CABLE ACCORDING TO AN EMBODIMENT OF THE INVENTION

[0114] The extracted cable 50 according to the embodiment of the invention is in [Fig.4] and the comparative cable C1 having the same characteristics as the cable 80 except the Jrmax in [Fig.5].

[0115] [Fig.6] represents a photograph of the cable 50 according to the invention.

[0116] Each protective reinforcement element 43, 45 and each hoop reinforcement element is formed, after extraction from the tire P, by an extracted cord 50 as described below. The cord 50 is obtained by embedding in a polymer matrix, in this case in a polymer matrix respectively forming each polymer matrix of each protective ply 42, 44 and of each hoop layer 52, 54 in which the protective reinforcement elements 43, 45 and hoop are respectively embedded.

[0117] The extracted cable 50 is single-layer metallic.

[0118] The cable 50 comprises a layer of structure IxN comprising a single layer 52 of N = 5 metallic wire elements 54 wound in a helix around a main axis A extending substantially parallel to the direction in which the cable extends along its greatest length.

[0119] In the illustrated embodiment, each metal wire element 54 comprises a single metal monofilament. Each metal wire element 54 also comprises a layer (not shown) of a metal coating comprising copper, zinc, tin, cobalt or an alloy of these metals, here brass. Each metal monofilament is made of carbon steel and has a mechanical strength here equal to 3100 MPa.

[0120] As described previously, the As value is determined by plotting a stress-strain curve of the extracted cable 50 by applying the ASTM D2969-04 standard of 2014.

[0121] The characteristics of the extracted cable 50 as well as the extracted cables 60, 70 and 80 according to the invention are reported in table 1 below as well as the characteristics of the cable of the state of the art EDT and of a comparative cable C1, comparative cable with respect to the cable 80.

[0122] [Tables 1] Cable EDT 50 60 70 80 Cl N / M / P 4 / 3 / 8 - - - - - N / cable direction SSS 5 / S 8 / S 4 / S 6 / S 6 / S Df(mm) 0.35 0.35 0.35 0.35 0.35 0.30 Dh (mm) 2.47 1.53 1.55 1.10 1.53 0.93 D (mm) 3.9 1.88 1.90 1.45 1.88 1.23 a(°) 23.3 28.3 26.2 19.1 26.2 17.3 Jr 0.38 2.43 1.33 1.42 1.82 0.44 As (%) 1.17 11.88 7.2 7.2 9 2.8 Dv (mm) 1.03 1.18 1.20 0.75 1.18 0.63 Rf (mm) 7.89 3.41 3.86 5.15 3.94 5.26 P (mm) 18 8.9 9.7 9.7 9.8 9.4 Dv / Df 0.72 3.40 3.46 2.17 3.40 2.10 Rf / Df 5.50 9.80 11.09 14.79 11.33 17.53 0.35 x ir x Dh 2.32 1.68 1.71 1.21 1.68 1.02 0.60 x ir x Dh4.65 2.89 2.93 2.08 2.83 1.75

[0123] Thus, the cables according to the invention make it possible to solve the problems mentioned in the preamble. The cables according to the invention (50, 60, 70 and 80) thanks to this maximum space available between the extreme wires Jr max, make it possible to improve the structural elongation compared to the cable of the state of the art and to the comparative cable Cl.

[0124] The invention is not limited to the embodiments previously described.

Claims

Claims

1. Cable extracted (50) from a polymer matrix, the extracted cable (50) comprising a single layer (52) consisting of N metallic wire elements (54) wound in a helix, each metallic wire element (54) of the layer (52) describing, when the cable (50) extends in a substantially rectilinear direction, a helix-shaped trajectory around a main axis (A) substantially parallel to the substantially rectilinear direction, such that, in a section plane substantially perpendicular to the main axis (A), the distance between the center of each metallic wire element (54) of the layer (52) and the main axis (A) is equal to half the helix diameter Dh and is substantially constant and equal for all the metallic wire elements (54) of the layer (52), the metallic wire elements (54) defining an internal arch (58) of the cable of diameter Dv,each metallic wire element (54) having a diameter Df and a helix curvature radius Rf defined by Rf=P / (ir x Sin(2a)) with P the pitch of each metallic wire element expressed in millimeters and a the helix angle of each metallic wire element (54), in which, Dh, D, Dv, Df and Rf being expressed in millimeters: 9 <Rf / Df<30, et 1,30 <Dv / Df< 4,5 ; et l’espace entre les fils est le jeu relatif défini par le jeu relatif Jr =(ji x Dh) / N x (Dh x Sin(ir / N) - (Df / Cos(a x jt / 1 80))), avec a étant l’angle d’hélice, exprimé en degrés, de chaque fil métallique (54) ; caractérisé en ce que : l’espace maximal disponible entre les fils extrêmes Jr max = N x Jr est tel que 0,35 x ir x Dh < Jr max < 0,60 x ir x Dh.,

2. Extracted cable (50) according to the preceding claim, in which 0.40 x ir x Dh < Jr max < 0.55 x ir x Dh.

3. An extracted cable (50) according to any preceding claim, wherein the structural elongation As is such that As > 4.0% determined by ASTM D2969-04 of 2014.

4. An extracted cable (50) according to any preceding claim, wherein the total elongation At is such that At > 10.0% determined by ASTM D2969-04 of 2014.

5. An extracted cable (50) according to any one of the preceding claims. preceding, in which 9 < Rf / Df < 17.

6. Extracted cable (50) according to any one of the preceding claims, wherein 1.30 < Dv / Df < 4.0, preferably 1.30 < Dv / Df < 3.

60.

7. Extracted cable (50) according to any one of the preceding claims, wherein the helix curvature radius Rf is such that 2 mm < Rf < 7 mm, preferably 2 mm < Rf < 5 mm and more preferably 3 mm < Rf < 5 mm.

8. Extracted cable (50) according to any one of the preceding claims, wherein the helix diameter Dh of each metallic wire element (54) is such that 0.40 mm < Dh < 2.00 mm, preferably 0.50 mm < Dh < 1.80 mm.

9. Extracted cable (50) according to any one of the preceding claims, wherein Df is such that 0.10 mm < Df < 0.50 mm, preferably 0.25 mm < Df < 0.45 mm and more preferably 0.25 mm < Df < 0.40 mm.

10. Extracted cable (50) according to any one of the preceding claims, wherein Dv is such that Dv > 0.46 mm, preferably 0.46 mm < Dv < 1.50 mm.

11. Extracted cable (50) according to any one of the preceding claims, wherein each metallic wire element (54) is wound at a pitch P such that 3 mm < P < 15 mm, preferably 3 mm < P < 12 mm.

12. Extracted cable (50) according to any one of the preceding claims, having a diameter D such that D < 2.50 mm, preferably 0.75 mm < D < 2.40 mm and more preferably 1.00 mm < D < 2.00 mm.

13. An extracted cable (50) according to any preceding claim, wherein the helix angle α of each wire element (54) is such that 13° < a < 30°.

14. Reinforced product (R), characterized in that it comprises a polymer matrix (Ma) and at least one extracted cable (50) according to any one of claims 1 to 13.

15. Tire (P), characterized in that it comprises at least one extracted cable (50) according to any one of claims 1 to 13 or a reinforced product according to claim 14.

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