Multi-strand cable with two multi-strand layers

Abstract

The present invention relates to a multi-strand cable (50) having two multi-strand layers, the cable (50) comprising an inner layer (CI) of a cable composed of a multi-strand (M1) with X = 1, comprising a plurality of strands (T1) with K>1 spirally wound around a main axis (A), each strand (T1) being a strand with at least two layers (C1, C3), an outer layer (CE) of the cable composed of a plurality of multi-strands (M2) with Y>1 wound around the inner layer (CI) of the cable, each multi-strand (M2) comprising a strand (T2) with L>1 spirally wound around an axis (A'), each strand (T2) being a strand with at least two layers (C1', C3'), and the multi-strand (M2) being spirally wound around the main axis (A). The cable (50) comprises TIFF2025519870000013.tif6157. The cable (50) has a structural elongation As such that As≧1.0%.

Description

Technical Field

[0001] The present invention relates to cords and tires provided with these cords.

Background Art

[0002] Cords of the 1×N structure are known from the prior art as described in International Publication No. WO 2016 / 131862. These cords comprise a single layer of N = 4 strands helically wound with a pitch of 20 mm. Each strand comprises an inner layer containing three inner wires helically wound with a pitch p1 = 6.7 mm for a part thereof, and an outer layer containing eight outer wires helically wound around the inner layer with a pitch p3 = 10 mm. The structural elongation of the cord is 2.8%, the diameter is 3.8 mm, the linear mass is 36.4 g / m, and the endurance criterion is equal to 3635 N·m / g.

[0003] These cords have the advantage of having a relatively high structural elongation, but there is room for improving the endurance criterion in order to improve the durability performance of the reinforcement while reducing shear in the polymer matrix.

[0004] Today, there is a need to develop new cords for application to crown plies, especially zero-degree plies such as hoop crown plies. The purpose of these plies is to hoop the tire in order to reduce shear at the edge of the ply and at the same time reduce the rigidity of the crown block against attack at the center.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The object of the present invention is to provide a cord with sufficient flexibility and structural elongation to enable the construction of a tire, reduce the rigidity of the crown blocks, and have improved durability criteria to withstand repeated tensile stress loading.

Means for Solving the Problems

[0007] For this purpose, one subject of the present invention is a multi-strand cord comprising two layers of multi-strand elements, the cord comprising an inner layer of the cord composed of a multi-strand element with X = 1 having a plurality of strands with K>1 wound helically around a main axis, each strand comprising an inner layer composed of Q1 internal metal wires (plural possible) with a diameter d1, and an inner layer of the cord comprising an outer layer composed of Q3 external metal wires with a diameter d3 wound around the inner layer, and an outer layer of the cord composed of a plurality of multi-strand elements with Y>1 wound around the inner layer of the cord, each multi-strand element comprising a plurality of strands with L>1 wound helically around an axis, each strand comprising an inner layer composed of Q1' internal metal wires (plural possible) with a diameter d1' and an outer layer of the cord having at least two layers comprising an outer layer composed of Q3' external metal wires with a diameter d3' wound around the inner layer, and comprising, the multi-strand elements are wound helically around the main axis, the cord

Number

Number

[0008] Thanks to this multi-strand cord configuration with a two-layer multi-strand element, the cord according to the present invention can obtain a cord having a sufficient mass of metal and keeping the metal fine wires in an elongated state, achieving an improvement in durability performance, and thus improving the compromise point between shear in the polymer matrix and the durability performance of the cord, and making it possible to improve the resistance to fracture.

[0009] On the other hand, thanks to its relatively low bending durability standard, the cord according to the present invention can reduce the stress level of the cord subjected to tensile stress load, and thus make it possible to extend the life of the tire. Specifically, the inventors of the present invention have found that the first criterion for improving the durability performance of the cord in a corrosive environment is not only the breaking force widely taught in the prior art, but also a durability criterion expressed by an index equal to the combination of bending stress, cord diameter and the mass of metal in the cord in the present application, that is: - The bending stress per unit curvature received by the internal and external fine wires of the strand [Number] When it is the maximum bending stress per unit curvature that the metal fine wire undergoes, in this type of cord, the inventors of the present invention have found that the tensile stress load on the cord generates both tensile stress and bending stress. Therefore, the reduction of this bending stress criterion has a favorable effect on the tensile durability performance of the cord by removing the share of the load caused by bending from the cord; - When the value obtained by dividing the metal mass in the cord by the diameter of the cord increases, the tensile stress of the cord can be mainly relaxed; where M is the linear mass of the cord (unit: g / m), which can be simply defined as the sum of the metal cross-sectional areas of all individual metal fine wires in the cord multiplied by the density of steel Rho = 7.79 g / cm3. In that case, the sum of the cross-sectional areas is determined by image processing related to the cross-section of the cord; The diameter D of the cord is measured on the cord in accordance with ASTM standard D2969-04.

[0010] By definition, the diameter of the cord is the diameter of the smallest circle that a cord without a trumpet can circumscribe on its inside.

[0011] The structural elongation As, which is a parameter well-known to those skilled in the art, is determined, for example, by applying ASTM standard D2969-04 (2014) to the cord tested to obtain a force-elongation curve. As is derived from the obtained curve as the elongation (unit: %) corresponding to the intersection point between the tangent line of the elastic part of the force-elongation curve and the elongation axis of the force-elongation curve. It should be recalled that the force-elongation curve includes a structural part, an elastic part, and a plastic part in the increasing direction of elongation. The structural part corresponds to the structural elongation of the cord caused by the different strands and metal fine wires constituting the cord moving together. The elastic part corresponds to the elastic elongation caused by the configuration of the cord, particularly the configuration of the angles of the various layers and the configuration of the diameters of the metal fine wires. The plastic part corresponds to the plastic elongation caused by the plasticity of the metal fine wires (irreversible deformation beyond the elastic limit).

[0012] In the present invention, the cord comprises a two-layer multi-strand element, which means that it comprises an assembly composed of a single-layer multi-strand element with Y>1 layers wound around a single-layer multi-strand element, where the cord has neither more nor less than this, and this assembly has a two-layer multi-strand element, meaning that it has neither one layer nor three layers, but only two layers.

[0013] In the present invention, the multi-strand element has a single layer of strands, which means that it comprises an assembly having a single layer of strands, where the multi-strand element has neither more nor less than this, and this assembly has a single layer of strands, meaning that it has neither zero layers nor two layers, but only one layer.

[0014] In one embodiment, the inner multi-strand element of the cord is surrounded by a polymer composition and subsequently by an outer layer.

[0015] Advantageously, each strand has a cylindrical layer.

[0016] Advantageously, each strand within the multi-strand element has two layers, which means that each strand comprises an assembly composed of two layers of metal wires, where the strand has neither more nor less than this, and this assembly has two layers of metal wires, meaning that it has neither one layer nor three layers, but only two layers. The outer layer of each strand contacts and is wound around the inner layer of that strand.

[0017] Very advantageously, each strand of the inner layer and each strand of the outer layer have cylindrical layers. It should be recalled that such cylindrical layers can be obtained when the various layers of the strand are wound with different pitches and / or when the winding directions of these layers are different for each layer. A strand with cylindrical layers has a very high permeability, unlike a strand with a dense layer with a much lower permeability where the pitch of all layers is the same and the winding direction of all layers is the same.

[0018] Advantageously, each strand of the inner layer and each strand of the outer layer are unsaturated, which means that there is sufficient space between the fine wires of the outer layer for the elastomer compound to penetrate each strand.

[0019] Preferably, the strands do not undergo preforming.

[0020] Advantageously, the cord as defined above is "bare" in the sense that it does not contain a polymer composition, and in particular the cord does not contain an elastomer composition.

[0021] The metal fine wire is understood to be a single metal fiber having a core mainly (i.e., more than 50% of its weight) or completely (100% of its weight) composed of a metal material such as carbon steel. The metal fine wire can advantageously comprise a layer of metal coating covering the core, and the metal coating is selected from zinc, copper, tin, and alloys of these metals such as brass, etc. Each fine wire is preferably made of pearlitic carbon steel or ferrite-pearlitic carbon steel.

[0022] The characteristic values described in this application for the bare cord are measured or determined from the cord as it is immediately after being manufactured, i.e., the cord before any step of embedding it in a polymer matrix, particularly an elastomer matrix.

[0023] In this application, the range of values denoted by the expression "between a and b" represents a range of values greater than a and less than b (i.e., excluding the end points a and b), whereas the range of values denoted by the expression "from a to b" means a range of values from the end point "a" to the end point "b", i.e., including the exact end points "a" and "b".

[0024] Advantageously, As ≧ 1.5%, preferably As ≧ 2.0%.

[0025] Another main subject of the present invention is a cord extracted from a polymer matrix, and this extracted cord A core inner layer composed of a multi-strand element with X = 1 having K > 1 strands spirally wound around a spindle, each strand being an inner layer composed of Q1 internal metal wire(s) of diameter d1, a core inner layer having at least two layers including an outer layer composed of Q3 external metal wires of diameter d3 wound around the inner layer, a code outer layer composed of a multi-strand element with Y > 1 wound around the core inner layer, each multi-strand element comprising L > 1 strands spirally wound around an axis, each strand being an inner layer composed of Q1' internal metal wire(s) of diameter d1', a code outer layer having at least two layers including an outer layer composed of Q3' external metal wires of diameter d3' wound around the inner layer, comprising The multi-strand element is spirally wound around the spindle, The extraction code (50) is

Number

Number

[0026] Preferably, the polymer base material is an elastomer base material.

[0027] The polymer base material, preferably an elastomer base material, is based on a polymer composition, preferably an elastomer composition.

[0028] It is understood that the polymer base material is a base material containing at least one polymer. Therefore, the polymer base material is based on a polymer composition.

[0029] What the elastomer base material means is a base material containing at least one elastomer. Therefore, a preferred elastomer base material is based on an elastomer composition.

[0030] The expression “based on” should be understood to mean that the composition contains the compounds of the various components used and / or the products of in-situ reactions, and some of these components are at least partially capable of reacting with each other and / or are intended to react during the various stages of composition manufacture, and thus the composition can be in a completely or partially cross-linked state or in an uncross-linked state.

[0031] It is understood that a polymer composition means that this composition contains at least one polymer. Preferably, such a polymer can be a thermoplastic substance, such as polyester or polyamide, a thermosetting polymer, an elastomer, such as natural rubber, a thermoplastic elastomer, or a combination of these polymers.

[0032] An elastomer composition is understood to mean that the composition contains at least one elastomer and at least one other component. Preferably, a composition containing at least one elastomer and at least one other component includes an elastomer, a crosslinking system, and a filler. Compositions that can be used for these plies are conventional compositions for skimming fibrous reinforcing elements, including diene elastomers such as natural rubber, reinforcing fillers such as carbon black and / or silica, crosslinking systems such as vulcanization systems, preferably sulfur, stearic acid, and zinc oxide, and optionally vulcanization accelerators and / or retarders and / or various additives. Adhesion between the metal wire and the matrix in which they are embedded is provided, for example, by a metal coating such as a brass layer.

[0033] The characteristic values described in this application for the extraction code are measured or determined on the code extracted from the polymer matrix, particularly the elastomer matrix, for example, with respect to a tire. Thus, for example, in the case of a tire, a piece of material on the outer side in the radial direction of the code to be extracted is removed so that the code to be extracted can be seen at the same height in the radial direction as the polymer matrix. This removal can be done by peeling using a cutter and a gripper, or otherwise by planing. Next, the end of the code to be extracted is cut off using a knife. Next, the code is pulled out of the matrix while applying a relatively shallow angle so as not to plasticize the code to be extracted. Next, the extracted code is carefully cleaned, for example, using a knife, taking care not to damage the surface of the metal wire, so as to separate any remaining polymer matrix locally adhering to the code.

[0034] To determine the linear mass of the extraction code, the cross-section of the code in the elastomer matrix is photographed, the surface area of the steel is determined using image processing, and then multiplied by the density of the steel.

[0035] In order to measure the linear mass of the extracted code, after the operations described above, it is also possible to measure the weight of 1 meter of the cleaned code and determine the average linear mass of the cleaned code over 10 measurements.

[0036] The advantageous features described below apply to both bare code and code extracted from a polymer matrix.

[0037] Advantageously, the reference V1 is 1000 N×m / g or more, preferably 1500 N×m / g or more.

[0038] Advantageously, the reference V1 is 2500 N×m / g or less.

[0039] Advantageously, M is in the range from 30 g / m to 150 g / m, preferably from 40 g / m to 120 g / m.

[0040] Preferably, the code has a code diameter such that D ranges from 3 mm to 9 mm, preferably from 4 mm to 7 mm.

[0041] By definition, the diameter of a strand is the diameter of the smallest circle that the strand can circumscribe on its inside.

[0042] Preferably, the diameters of the fine metal wires are, independently of each other, in the range from 0.15 mm to 0.50 mm, preferably from 0.18 mm to 0.35 mm, more preferably from 0.20 mm to 0.30 mm.

[0043] Preferably, all the fine wires of one and the same layer for a given strand have substantially the same diameter. Advantageously, all the outer strands have substantially the same diameter. What "substantially the same diameter" means is that the fine wires or strands have the same diameter within the range of industrial tolerances.

[0044] Advantageously, Y is equal to 6, 7, 8, 9 or 10, preferably Y = 6, 7 or 8, more preferably Y = 6.

[0045] Advantageously, K = 2, 3 or 4, preferably K = 3 or 4.

[0046] Advantageously, L = 2, 3 or 4, preferably L = 3 or 4.

[0047] In the first embodiment, each strand of the inner layer has two layers.

[0048] Advantageously, each strand of the outer layer has two layers.

[0049] Advantageously, in this first embodiment, in a preferred variant, each strand of the inner layer and the outer layer has two layers.

[0050] In the second embodiment, each strand of the inner layer has three layers, an intermediate layer composed of intermediate metal wires Q2 wound around the inner layer, and an outer layer composed of outer metal wires Q3 wound around the intermediate layer. and is provided with.

[0051] Advantageously, each strand of the outer layer has three layers, an intermediate layer composed of intermediate metal wires Q2' wound around the inner layer, and an outer layer composed of outer metal wires Q3' wound around the intermediate layer. and is provided with.

[0052] Advantageously, in this second embodiment, in a preferred variant, each strand of the inner layer and the outer layer has three layers.

[0053] Advantageously, each strand is of the type where in-situ gumming is not performed. Not performing in-situ gumming means that before the strands are combined with each other, each strand is composed of fine wires of various layers and does not show any polymer composition, especially any elastomer composition.

[0054] Strands of the internal multi-strand element of the cord according to the present invention

[0055] Advantageously, Q1 = 1, 2, 3 or 4, preferably Q1 = 1, 2 or 3, more preferably Q1 = 1 or 3.

[0056] Advantageously, Q3 = 5, 6, 7, 8, 9 or 10, preferably Q3 = 6, 7, 8 or 9, more preferably Q3 = 6 or 9.

[0057] In one embodiment, Q1 = 1.

[0058] Advantageously, Q3 = 5, 6 or 7, preferably Q3 = 6.

[0059] In another preferred embodiment, Q1> 1, preferably Q1 = 2, 3 or 4.

[0060] Advantageously, Q3 = 7, 8, 9 or 10, preferably Q3 = 7, 8 or 9.

[0061] In the first variant, Q1 = 2, Q3 = 7 or 8, preferably Q1 = 2, Q3 = 7.

[0062] In the second variant, Q1 = 3, Q3 = 7, 8 or 9, preferably Q1 = 3, Q3 = 8.

[0063] In the third variant, Q1 = 4, Q3 = 7, 8, 9 or 10, preferably Q1 = 4, Q3 = 9.

[0064] Strands of the external multi-strand element of the cord according to the present invention

[0065] Advantageously, Q1' = 1, 2, 3 or 4, preferably Q1' = 1, 2 or 3, more preferably Q1' = 1 or 3.

[0066] Advantageously, Q3’ = 5, 6, 7, 8, 9 or 10, preferably Q3’ = 6, 7, 8 or 9, more preferably Q3’ = 6 or 9.

[0067] In one embodiment, Q1’ = 1.

[0068] Advantageously, Q3’ = 5, 6 or 7, preferably Q3’ = 6.

[0069] In another preferred embodiment, Q1’ > 1, preferably Q1’ = 2, 3 or 4.

[0070] Advantageously, Q3’ = 7, 8, 9 or 10, preferably Q3’ = 7, 8 or 9.

[0071] In the first variant, Q1’ = 2, Q3’ = 7 or 8, preferably Q1’ = 2, Q3’ = 7.

[0072] In the second variant, Q1’ = 3, Q3’ = 7, 8 or 9, preferably Q1’ = 3, Q3’ = 8.

[0073] In the third variant, Q1’ = 4, Q3’ = 7, 8, 9 or 10, preferably Q1’ = 4, Q3’ = 9.

[0074] Advantageously, Q1 = 1 and Q3 = 6, Q1’ = 1 and Q3’ = 6.

[0075] Reinforcement product according to the present invention

[0076] Another subject of the invention is a reinforcing product comprising a polymer matrix and at least one code or extraction code as defined above.

[0077] Advantageously, the reinforcing product comprises one or more codes according to the invention embedded in the polymer matrix, and in the case of a plurality of codes, the codes are arranged side by side in the main direction.

[0078] Tire according to the present invention

[0079] Another subject of the present invention is a tire comprising at least one extraction code or reinforcement product as defined above.

[0080] A tire with an extraction code means a tire with a code whose characteristics measured before extraction from the tire are the characteristics of the extracted code, and this code, before being incorporated into the tire, is a code such as the code described above in this specification.

[0081] Preferably, the tire has a carcass reinforcement on which a crown reinforcement is radially mounted, the crown reinforcement being anchored to two beads and itself carrying a tread, and the crown reinforcement being joined to the beads by two sidewalls and comprising at least one code as defined above.

[0082] In one preferred embodiment, the crown reinforcement comprises a protection reinforcement, a working reinforcement, and a hoop reinforcement comprising at least one code as defined above, the protection reinforcement being sandwiched radially between the tread and the working reinforcement, and the hoop reinforcement preferably being sandwiched between two plies of the working reinforcement.

[0083] The code is in particular intended for industrial vehicles selected from "large vehicles" (i.e., subways, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles), agricultural vehicles or plant construction vehicles, or other transport or handling vehicles.

[0084] Preferably, the present tire is for a vehicle of the plant construction type. Thus, the present tire has a size such that the diameter of the seat portion of the rim intended to receive the tire is 40 inches or more in inches.

[0085] The present invention also relates to an assembly according to the present invention, or a rubber article provided with the impregnated assembly according to the present invention. What the rubber article means is any kind of article made of rubber such as a ball, a non-pneumatic object such as a non-pneumatic tire casing, a conveyor belt or an endless track. A better understanding of the present invention should be obtained by reading the following examples, which are given merely as non-limiting examples and made with reference to the drawings.

Brief Description of the Drawings

[0086]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0087] Example of a tire according to the present invention

[0088] Reference systems X, Y, Z corresponding to the normal axial direction (X), radial direction (Y) and circumferential direction (Z) of the tire are shown in FIGS. 1 and 2.

[0089] The "median circumferential surface" M of the tire is a plane perpendicular to the rotation axis of the tire and equidistant from the annular reinforcing structures of each bead.

[0090] Figures 1 and 2 depict a tire, generally referenced by the numeral 10, according to the present invention.

[0091] The tire 10 is for large vehicles of the plant construction type, e.g. the "dump truck" type. Accordingly, the tire 10 has dimensions of size 53 / 80R63.

[0092] The tire 10 has a crown 12 reinforced by a crown reinforcement 14, two sidewalls 16, and two beads 18, each of these beads 18 being reinforced using an annular structure, in this example a bead wire 20. The crown reinforcement 14 radially supports the tread 22 and is connected to the beads 18 by the sidewalls 16. The carcass reinforcement 24 is firmly fixed by the two beads 18, in this example wound around the two bead wires 20 and provided with a turn-up 26 positioned towards the outside of the tire 20, the turn-up 26 being shown here mounted on a wheel rim 28. The carcass reinforcement 24 radially supports the crown reinforcement 14.

[0093] The carcass reinforcement 24 comprises at least one carcass ply 30 reinforced by radially disposed carcass cords (not shown). The carcass cords are positioned substantially parallel to each other and form an angle between 80° and 90° with respect to the median circumferential plane M (a plane perpendicular to the axis of rotation of the tire, located midway between the two beads 18 and passing through the center of the crown reinforcement 14), extending from one bead 18 to the other.

[0094] The tire 10 also comprises a sealing ply 32, made of elastomer (commonly known as the "inner liner"), which defines the radially inner surface 34 of the tire 10 and is intended to protect the carcass ply 30 from the diffusion of air coming from the inner space of the tire 10.

[0095] The crown reinforcement 14 includes a protection reinforcement 36 disposed radially inward of the tread 22 from the outside to the inside of the tire 10, a working reinforcement 38 disposed radially inward of the protection reinforcement 36, and a hoop reinforcement 40 sandwiched between two plies 48, 46 of the working reinforcement 38 in the radial direction. Accordingly, the protection reinforcement 36 is sandwiched between the tread 22 and the working reinforcement 38 in the radial direction.

[0096] The protection reinforcement 36 includes first and second protection plies 42, 44 provided with protection metal cords, and the first ply 42 is disposed radially inward of the second ply 44. Optionally, the protection metal cords form an angle with the circumferential direction Z of the tire in a range equal to at least 10°, preferably from 10° to 35°, more preferably from 15° to 35°.

[0097] The working reinforcement 38 includes first and second working plies 46, 48, and the first ply 46 is disposed radially inward of the second ply 48.

[0098] The hoop reinforcement 40, also called a limiter unit, includes at least one cord 50 forming an angle in a range equal to at most 10°, preferably from 0° to 5°, with respect to the circumferential direction Z of the tire 10.

[0099] Example of a Reinforcement Product According to the Invention

[0100] FIG. 3 represents a reinforcement product, generally designated by reference numeral 100, according to the invention. The reinforcement product 100 includes at least one cord 50, a plurality of cords 50 in this example, embedded in a polymer matrix 102.

[0101] Figure 3 shows the polymer matrix 102 and the cords 50 in the reference system X, Y, Z, where the direction Y is the radial direction, and the directions X and Z are the axial and circumferential directions. In Figure 3, the reinforcing product 100 includes a plurality of cords 50 arranged side by side in the main direction X, extending parallel to each other within the reinforcing product 100, and collectively embedded in the polymer matrix 102. Here, the polymer matrix 102 is an elastomeric matrix based on an elastomer composition.

[0102] Cord according to the first embodiment of the present invention

[0103] Figure 4 shows the cord 50 according to the first embodiment of the present invention.

[0104] Referring to Figure 5, each peripheral hoop reinforcing element is formed by the extraction cord 50' described below after extraction from the tire 10. The cord 50 is obtained by embedding it in the polymer matrix, in this example, in the polymer matrix forming each polymer matrix of each working ply respectively.

[0105] Figure 7 shows a photograph of the cord 50 in the polymer matrix.

[0106] The cord 50 and the extraction cord 50' are made of metal and are of the multi-strand type with two multi-strand cylindrical layers. Therefore, it will be understood that the number of layers of strand elements from which the cord 50 or 50' is made is two, neither more nor less.

[0107] At least 50%, preferably at least 60%, more preferably at least 70%, and most preferably, each metal wire of the cord has a steel core with a composition conforming to NF-EN standard 10020 (September 2000) and a carbon content C > 0.80%, preferably C ≥ 0.82%. At least 50%, preferably at least 60%, more preferably at least 70%, and most preferably, each metal wire of the cord has a steel core with a composition conforming to NF-EN standard 10020 (September 2000) and a carbon content C ≤ 1.20%, preferably C ≤ 1.10%. Here, each metal wire has a steel core with a composition conforming to NF-EN standard 10020 (September 2000) and a carbon content C = 0.86%.

[0108] Each wire has a breaking strength denoted as Rm such that 2500 ≤ Rm ≤ 3100 MPa. The steel for these wires is considered to be of the SHT ("super high tension") grade. Lower grade wires, such as those of the NT ("normal tension") or HT ("high tension") grades, can be used in exactly the same way as other wires, for example, higher grade wires such as the UT ("ultra high tension") or MT ("mega tension") grades.

[0109] Method for manufacturing the cord according to the present invention

[0110] Here, an example of a method for manufacturing the multi-strand cord 50 will be described.

[0111] Each of the above internal strands T1 is manufactured according to a known method involving the following steps, preferably continuously in-line: - First, a first assembly step of cabling or twisting six external wires F3 around the internal wire F1 of the internal layer C1 in the S direction at a pitch p3 to form the external layer C3 at the first assembly point. - Preferably, a final twist balancing step. That is. Each of the above external strands T2 is manufactured according to a known method involving the following steps, preferably continuously in-line: - First, a first assembly step of forming an outer layer C3' at a first assembly point by twisting or winding six external fine wires F3' around an internal fine wire F1' of an internal layer C1' in the S direction with a pitch p3'. - Preferably, a final twist balance step. That's it.

[0112] Here, what "twist balance" means is well-known to those skilled in the art, but it is the elimination of the residual torque (or elastic recovery of the twist) applied to each fine wire of the strand in the outer layer.

[0113] After this final twist balance step, the manufacture of the strand is completed. Each strand is wound onto one or more receiving reels for storage prior to subsequent operations of twisting and assembling the basic strands to obtain a multi-strand cord.

[0114] To manufacture the multi-strand cord of the present invention, the method is, as is well-known to those skilled in the art, to twist the previously obtained strands using a twisting machine rated for strand assembly.

[0115] In the step of manufacturing the multi-strand element M1 of the internal layer CI, the internal strands T1 with K = 3 are assembled in the S direction with a pitch P1 by twisting to form the multi-strand element M1 of the internal layer CI at the first assembly point.

[0116] In the step of manufacturing the multi-strand element M2 of the external layer CE, the external strands T2 with L = 3 are assembled in the S direction with a pitch P2 by twisting to form the multi-strand element M2 of the external layer CE at the first assembly point.

[0117] Next, in a subsequent manufacturing process, the external multi-strand elements M2 with Y = 6 are assembled in the Z direction with a pitch pe by twisting to form an assembly of the layers CI and CE. Perhaps, in the last assembly step, the horn F is wound around the previously obtained assembly in the S direction with a pitch pf.

[0118] Next, cord 50 is incorporated by calendering into a composite base fabric formed from a known composition based on natural rubber and carbon black as reinforcing fillers, which has been conventionally used in the production of the crown reinforcement of radial tires. This composition essentially contains, in addition to an elastomer and a reinforcing filler (carbon black), an antioxidant, stearic acid, extender oil, cobalt naphthenate as an adhesion promoter, and finally a vulcanization system (sulfur, accelerator, and ZnO).

[0119] The composite base fabric reinforced by these cords has an elastomer composition base material formed from two thin skim layers of an elastomer composition having a thickness in the range of between 1 mm and 4 mm each, which are laminated on both sides of the cords. The calendering pitch (the interval at which the cords are laid on the elastomer composition fabric) is in the range of from 4 mm to 8 mm.

[0120] Next, these composite base fabrics are used as working plies in the crown reinforcement during the method of manufacturing a tire, and the method steps are known to those skilled in the art in another way.

[0121] The cord according to the second embodiment of the present invention

[0122] FIG. 6 shows cord 60 according to the second embodiment of the present invention.

[0123] Unlike the first embodiment described above, cord 60 according to the second embodiment is such that Q1 = Q1' = 1; Q2 = Q2' = 5; and Q3 = Q3' = 10.

[0124] Table 1 below summarizes the characteristics of various cords 50, 50' and 60.

[0125]

Table 1

[0126] In addition, Table 2 below summarizes the features of the codes of the prior art described in International Publication No. 2016 / 131862.

[0127]

Table 2

[0128] It can be seen that the cords 50, 50' and 60 according to the present invention exhibit sufficient flexibility and structural elongation, enable the construction of tires, reduce the rigidity of the crown blocks, and make it possible to obtain cords with improved durability standards compared to the cords of the prior art to cope with repeated tensile stress loads.

[0129] The present invention is not limited to the above-described embodiments.

Explanation of Reference Numerals

[0130] 50 Cord according to the first embodiment A Spindle A' Axis C1 Inner layer of the cord inner layer C1' Inner layer of the cord outer layer C3 Outer layer of the cord inner layer C3' Outer layer of the cord outer layer CE Cord outer layer CI Cord inner layer F1 Inner metal fine wire of the inner layer of the cord inner layer F1' Inner metal fine wire of the inner layer of the cord outer layer F3 Outer metal fine wire of the outer layer of the cord inner layer F3' Outer metal fine wire of the outer layer of the cord outer layer M1 Multi-strand element of the cord inner layer M2 Multi-strand element of the cord outer layer T1 Inner strand T2 Outer strand

Claims

1. A multistrand code (50) having two multistrand layers, wherein the code (50) is A code interior layer (CI) composed of a multi-strand element (M1) with X=1, having multiple strands (T1) with K>1 wound spirally around a main axis (A), wherein each strand (T1) is An inner layer (C1) composed of internal metal fine wires (F1) of Q1 with diameter d1, The outer layer (C3) is composed of an outer metal fine wire (F3) with diameter d3 and Q3 wound around the inner layer (C1), The code interior layer (CI) has at least two layers (C1, C3) equipped with, The outer cord layer (CE) is composed of a plurality of multi-strand elements (M2) with Y > 1 wound around the inner cord layer (CI), wherein each multi-strand element (M2) comprises a strand (T2) with L > 1 wound spirally around an axis (A'), and each strand (T2) is An inner layer (C1') composed of internal metal nanowires (F1') of diameter d1' Q1' and A cord outer layer (CE) having at least two layers (C1', C3'), comprising: an outer layer (C3') composed of an outer metal fine wire (F3') of diameter d3' and Q3' wound around the inner layer (C1'), Equipped with, The multi-strand element (M2) is wound spirally around the main shaft (A), The aforementioned code (50) is, [Math 1] It has; here [Math 2] (Unit: MPa.mm) is the maximum bending stress per unit curvature experienced by the internal and external fine wires of the internal and external strands, di and di' are the diameters of the metal fine wires, i and i' are in the range of 1 to 3, and Msteel = 200,000 MPa. M is the wire mass (in g / m) of the code (50), and M is obtained by multiplying the sum of the metal cross-sectional areas of all the fine metal wires in the code by the density Rho of steel, where Rho = 7.79 g / cm³. 3 And, D is the diameter (in mm) of the aforementioned code (50), The code (50) has a structural elongation As such that As ≥ 1.0%, the structural elongation As is determined by applying ASTM standard D2969-04 (2014) to the code (50) to obtain a force-elongation curve, and the structural elongation As is equal to the elongation (in %) corresponding to the intersection of the tangent to the elastic portion at a certain point along the elastic portion of the force-elongation curve and the elongation axis of the force-elongation curve.

2. Code (50) according to claim 1, wherein As ≥ 1.5%.

3. A multi-strand cord (50') having two multi-strand layers extracted from a polymer base material (102), wherein the extracted cord (50') is A code interior layer (CI) composed of a multi-strand element (M1) with X=1, having multiple strands (T1) with K>1 wound spirally around a main axis (A), wherein each strand (T1) is An inner layer (C1) composed of internal metal fine wires (F1) of Q1 with diameter d1, A code inner layer (CI) having at least two layers (C1, C3), comprising: an outer layer (C3) composed of an outer metal fine wire (F3) with diameter d3 and Q3 wound around the inner layer (C1); The outer cord layer (CE) is composed of a plurality of multi-strand elements (M2) with Y > 1 wound around the inner cord layer (CI), wherein each multi-strand element (M2) comprises a strand (T2) with L > 1 wound spirally around an axis (A'), and each strand (T2) is An inner layer (C1') composed of internal metal nanowires (F1') of diameter d1' Q1' and A cord outer layer (CE) having at least two layers (C1', C3'), comprising: an outer layer (C3') composed of an outer metal fine wire (F3') of diameter d3' and Q3' wound around the inner layer (C1'), Equipped with, The multi-strand element (M2) is wound spirally around the main shaft (A), The aforementioned code (50') is, [Math 3] It has; here [Math 4] (Unit: MPa.mm) is the maximum bending stress per unit curvature experienced by the internal and external fine wires of the internal and external strands, di and di' are the diameters of the metal fine wires, i and i' are in the range of 1 to 3, and Msteel = 200,000 MPa. M is the wire mass (in g / m) of the aforementioned code (50'), and is obtained by multiplying the sum of the metal cross-sectional areas of all the fine metal wires in the code by the density Rho of steel, where Rho = 7.79 g / cm³. 3 And, D is the diameter (in mm) of the aforementioned code (50'), The code (50') has a structural elongation As' such that As'≧0.3%, and the structural elongation As' is determined by applying ASTM standard D2969-04 (2014) to the code (50') to obtain a force-elongation curve, and is equal to the elongation (in %) corresponding to the intersection of the tangent to the elastic portion at a certain point along the elastic portion of the force-elongation curve and the elongation axis of the force-elongation curve.

4. The aforementioned standard V1 is 1000 N × m / g or more, the code (50; 50') according to claim 1 or 3.

5. The code (50; 50') according to claim 1 or 3, wherein the standard V1 is 2500 N × m / g or less.

6. M is the code (50; 50') according to claim 1 or 3, in the range of 30 g / m to 150 g / m.

7. Each strand (T1) of the inner layer (CI) has two layers (C1, C3), the code (50; 50') according to claim 1 or 3.

8. Each strand (T2) of the outer layer (CE) has two layers (C1', C3'), the code (50; 50') according to claim 1 or 3.

9. A reinforced product (100) comprising an elastomer matrix (102) and at least one code (50') such that the properties measured after extraction are the properties of the extraction code (50') described in claim 3.

10. A tire (10) comprising at least one code (50') such that the characteristics measured after extraction are the characteristics of the extracted code (50') described in claim 3, or the reinforcing product described in claim 9.

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