Two-layer multi-strand cable with improved surface breakdown energy

Abstract

The present invention relates to a multi-strand cable (50) comprising an inner cable layer (CI) consisting of K=1 inner strands (TI) with two plies (C1, C3) of which the inner ply (C1) consists of Q wires (F1) and the outer ply (C3) consists of N outer wires (F3), and an outer cable layer (CE) consisting of L>1 outer strands (TE) wound on the inner cable layer (CI), with the inner ply (C1) consisting of Q' inner wires (FT) and the outer ply (C3') consisting of two plies (CT, C3') of which the inner ply (C3') consists of N' outer wires (F3'). The cable (50) has a surface rupture energy ES≥145 N.mm -1 and TIFF2023503055000027.tif21153 where TIFF2023503055000028.tif21153 is the total breaking force of Nc metal wires, TIFF2023503055000029.tif21153 is the sum of the total elongation rates of the Nc metal wires, Cfrag is the embrittlement factor of the cable (50), and D is the diameter of the cable (50).

Description

[Technical Field]

[0001] This invention relates to cords and tires including these cords. [Background technology]

[0002] Prior art, particularly from International Publication No. 2016 / 017655, provides a tire for a plant construction vehicle having a radial carcass reinforcement comprising a tread section, two non-stretchable bead sections, two sidewall sections connecting the bead sections to the tread section, and a crown reinforcement positioned circumferentially between the carcass reinforcement and the tread section. This crown reinforcement comprises four plies reinforced with reinforcing elements such as metal cords, the cords of one ply being embedded in the elastomer matrix of the ply.

[0003] This crown reinforcement includes multiple working plies, each containing multiple filamentary reinforcing elements. Each working filamentary reinforcing element is a two-layer multi-strand cord having an inner layer of a cord composed of K=1 two-layer internal strands, including an inner layer composed of Q=3 internal metal threads with a diameter d1=0.25 mm and an outer layer composed of N=8 external metal threads with a diameter d3=0.33 mm wound around the inner layer, and an outer layer of L=6 two-layer external strands, including an inner layer composed of Q=3 internal metal threads with a diameter d1'=0.29 mm and an outer layer composed of N'=9 external metal threads with a diameter d3'=0.29 mm wound around the inner layer. At a breaking force of 17,572 N, the diameter of the unwrapped cord is equal to 3.72 mm.

[0004] On the other hand, when a tire passes over an obstacle, such as a stone, there is a risk that these obstacles will puncture the tire down to the crown reinforcement. These punctures allow corrosive agents to penetrate the tire's crown reinforcement, shortening the tire's lifespan.

[0005] On the other hand, it has been found that the crown ply cord may show damage due to relatively significant deformation and load being applied to the cord, especially when the tire passes over an obstacle.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] One subject of the present invention is a cord that enables reduction or elimination of the number of damages and perforations.

Means for Solving the Problems

[0008] For this purpose, one subject of the present invention is a two-layer multi-strand cord, an inner layer composed of Q = 2, 3 or 4 internal metal threads, and, an outer layer composed of N external metal threads with a diameter d3 wound around the inner layer, the inner layer of the cord composed of K = 1 two-layer internal strand including, an inner layer composed of Q' = 2, 3 or 4 internal metal threads, and, an outer layer composed of N' external metal threads with a diameter d3' wound around the inner layer, and an outer layer of the cord composed of L>1 two-layer external strands wound around the inner layer of the cord, the cord has a breaking energy ES per unit area of ES≧150N.mm ,

[0008] , , , , , , , , , , , , , , , , , -1 , , ,

[0007] , , , , having, TIFF2023503055000002.tif21153 where, TIFF2023503055000003.tif21153 is the sum of the breaking forces in Newton units of Nc threads, Nc = Q + N + L×(Q’ + N’) is the total number of metal threads, D is the diameter of the cord in mm units, TIFF2023503055000004.tif21153 is the sum of the total elongation rates of Nc threads and is dimensionless, Cfrag is the dimensionless weakening coefficient of the cord, TIFF2023503055000005.tif22153 where, d3 and d3’ are expressed in mm units, αf is the contact angle between the outer metal threads of the inner strand and the outer metal threads of the outer strand and is expressed in radians, αt is the helix angle of each outer strand and is expressed in radians, Cste = 1500N.mm -2 is the cord.

[0009] The cord according to the present invention has a relatively high breaking energy per unit area, so it reduces perforation, thus extending the life of the tire and also making it possible to reduce the number of damages. Specifically, the inventors of the present invention have found that the criterion for reducing the breakage of the cord is not only the breaking force widely taught in the prior art, but also an index equal to the product of the breaking force, the breaking elongation, and the weakening coefficient of the cord divided by the diameter of the cord, which is the breaking energy per unit area.

[0010] The weakening coefficient is designed to account for the loss of tensile behavior of the cord resulting from the lateral weakening of inter-thread contact at the level of the outer metal threads in the inner and outer layers. This weakening coefficient depends on the number of outer metal threads in the inner layer, the contact angle between the inner strand and the or each outer strand, the diameter d3 of the outer metal threads in the inner layer and the diameter d3' of the outer metal threads in the outer layer, the helical angle of the outer strands, and the breaking force of the outer strands. Thus, a strong cord has a weakening coefficient close to 1, while a weakened cord has a suboptimal weakening coefficient closer to 0.5.

[0011] Specifically, prior art codes either have a relatively high breaking force but an insufficient weakening coefficient, or, as in Example 8 of International Publication No. 2016 / 017655, the weakening coefficient is optimal, i.e., close to 1, but the breaking force is relatively low. In either case, prior art codes have a relatively low breaking energy per unit area. The code according to the present invention exhibits a relatively high breaking elongation and a relatively high breaking energy per unit area, due to its relatively high weakening coefficient and relatively high breaking force.

[0012] A numerical range expressed as "between a and b" represents a range greater than a and less than b (i.e., excluding endpoints a and b), while a numerical range expressed as "from a to b" means a numerical range from endpoint a to endpoint b (i.e., including the exact endpoints a and b).

[0013] By definition, the diameter of a strand is the diameter of the smallest circle that can circumscribe the strand.

[0014] The diameter of the cord is preferably the diameter of the smallest circle circumscribing the cord, excluding the wrapper. The cord should have a diameter D such that D ≤ 6.0 mm, and preferably a diameter D such that 5.0 mm ≤ D ≤ 5.5 mm. The diameter D is measured on the cord according to ASTM standard D2969-04.

[0015] In this invention, the code has two strands, that is, it includes an assembly made up of exactly two strands, meaning the assembly has only two strands and not one or three.

[0016] In one embodiment, the inner strands of the cord are surrounded by a polymer compound and then surrounded by an outer layer.

[0017] It is advantageous for the internal strand to have a cylindrical layer.

[0018] It is advantageous for each outer strand to have a cylindrical layer.

[0019] It is highly advantageous for the inner strands and each outer strand to have a cylindrical layer. Such a cylindrical layer can be conceivable when the various layers of the strand are wound at different pitches and / or when the winding direction of these layers differs from layer to layer. Unlike strands containing dense layers where all layers have the same pitch and winding direction and exhibit much lower permeability, strands containing a cylindrical layer are highly permeable.

[0020] The internal strand is a two-layer strand. The internal strand contains a group of threads that are strictly composed of two layers of threads; that is, a group of threads has only two layers of threads, not one or three layers.

[0021] The outer strand is a two-layer strand. The outer strand contains a group of threads that are strictly composed of two layers of threads; that is, a group of threads has only two layers of threads, not one or three layers.

[0022] As is well known, the pitch of a strand represents the length of that strand measured parallel to the axis of the cord, and it will be recalled that a strand having this pitch will subsequently rotate 180° around the axis of the cord. Similarly, the pitch of a thread represents the length of that thread measured parallel to the axis of the strand on which it is located, and a thread having this pitch will subsequently rotate 180° around the axis of the strand.

[0023] The winding direction of a strand or thread layer is the direction in which the strand or thread is formed relative to the axis of the cord or strand. The winding direction is generally represented by the letters Z or S.

[0024] The thread and strand pitch, winding direction, and diameter are determined according to the 2014 ASTM standard D2969-04.

[0025] The contact angle between the outer metal threads of the inner strand and the outer metal threads of the outer strand is the angle αf shown in Figure 7. The schematic diagram of the cord according to this invention shows the axis A-A' of the cord with the inner and outer layers wound around it. In this diagram, only the two metal threads of the outer layer of the outer strand are held in place so that the angle αf, which is the contact angle between the outer metal threads of the inner strand and the outer metal threads of the outer strand, is clearly visible. This contact angle is one of the relevant parameters in determining the cord weakening coefficient, as a smaller angle reduces cord weakening.

[0026] The helical angle αt of each outer strand is a parameter well known to those skilled in the art and can be calculated using the formula tanαt = 2 × π × Re / Pe, where pe is the winding pitch of each outer strand in millimeters, re is the helical radius of each outer strand in millimeters, and tan is the tangent function. αt is expressed in degrees.

[0027] By definition, the spiral radius Re of the outer layer of a code is the radius of a theoretical circle that passes through the center of the outer strand of the outer layer in a plane perpendicular to the axis of the code.

[0028] The total elongation rate At, a parameter well known to those skilled in the art, is determined by applying the 2014 ASTM standard D2969-04 to a thread being tested, for example, by obtaining a force-elongation curve. From this obtained curve, At is estimated as the elongation rate in percentage units corresponding to the projection onto the elongation axis of the thread's fracture point on the force-elongation curve, i.e., the point where the load increases to the maximum value of the fracture force (Fm) and then decreases sharply after failure. If the decrease with respect to Fm exceeds a certain level, it means that the thread has failed.

[0029] It is preferable that the strands are not preformed.

[0030] It is advantageous for the cord to be made of metal. The term “metallic cord” is understood, by definition, to mean a cord formed of threads that are primarily (i.e., more than 50% of these threads) or entirely (100% of the threads) made of metallic material. Such metallic material is preferably implemented using steel material, and more preferably using pearlite (or ferrite-pearlite) carbon steel material, which will be referred to below as “carbon steel,” or stainless steel material (by definition, stainless steel containing at least 11% chromium and at least 50% iron). On the other hand, it is of course possible to use other steels or other alloys.

[0031] When carbon steel is advantageously used, its carbon content (weight %) is preferably 0.4% to 1.2%, particularly 0.5% to 1.1%, as these content levels represent a good compromise between the mechanical properties required for the tire and the workability of the threads.

[0032] The metal or steel used, whether specifically carbon steel or stainless steel, can be coated with a metal layer that improves the workability of the metal cord and / or its components, or the usability of the cord and / or tire itself, such as adhesion, corrosion resistance, or aging resistance. According to one preferred embodiment, the steel used is covered with a layer of brass (Zn-Cu alloy) or zinc.

[0033] It is preferable that all threads in one identical layer of a given (internal or external) strand have substantially the same diameter. It is advantageous for external strands to all have substantially the same diameter. "Substantially the same diameter" means that the threads or strands have the same diameter within the range of industrial tolerances.

[0034] It is advantageous for the outer strands to be spirally wound around the inner strands with a pitch PE ranging from 40 mm to 100 mm, preferably ranging from 50 mm to 90 mm.

[0035] The code according to the present invention is 120 N. mm -1 The present invention has significantly improved energy per unit area compared to prior art codes which have energy per unit area. Specifically, the inventors of the present invention assume the theory that the more inter-thread contact there is in the most stressed inter-strand region, that is, the more contact there is between the external metal threads of the inner strands and the external metal threads of the outer strands, the more the weakening load is suppressed over the number of contacts. This contact load depends on the load that each strand can react to, i.e., the code load divided by the number of strands. In order to optimize these contacts, the inventors of the present invention assume the theory that in order to optimize the contact within the code, it is necessary for the contact between the external metal threads of the inner strands and the external metal threads of the outer strands, specifically the contact angle, to have good geometric properties.

[0036] ES ≥ 160 N. mm -1It is advantageous that ES ≥ 165 N. mm -1 Preferably, ES ≥ 170 N. mm -1 It is even more preferable that this be the case.

[0037] Breaking force: TIFF2023503055000006.tif21153 It is advantageous for Fr ≥ 25,000 N, preferable for Fr ≥ 26,000 N, and even more preferable for Fr ≥ 28,000 N. The breaking force is measured according to ASTM standard D2969-04. As mentioned above, this code has a relatively high breaking force to maximize the breaking energy per unit area.

[0038] Another subject of the present invention is an extracted code extracted from a polymer matrix, Q = an inner layer composed of 2, 3, or 4 internal metal threads, and The outer layer consists of N outer metal threads with a diameter of d3 wound around the inner layer. The inner layer of the code consists of K=1 2-layer internal strands, Q' = an inner layer composed of 2, 3, or 4 internal metal threads, and The outer layer consists of N' outer metal threads with a diameter d3' wound around the inner layer, The outer layer of the code consists of L>1 2-layer outer strands wrapped around the inner layer of the code, The extraction code is equipped with a fracture energy ES' ≥ 150 N. mm -1 It has, TIFF2023503055000007.tif21153 And here, TIFF2023503055000008.tif21153 This is the sum of the breaking forces in Newtons of Nc threads, Nc = Q + N + L × (Q' + N') is the total number of metal threads. D is the diameter of the cord in millimeters. TIFF2023503055000009.tif21153 is the sum of the total elongation ratios of Nc threads and is dimensionless, Cfrag’ is the dimensionless weakening coefficient of the code, TIFF2023503055000010.tif22153 and, where Cp is the penetration coefficient of the code, d3 and d3’ are expressed in mm units, αf is the contact angle between the external metal threads of the internal strand and the external metal threads of the external strand and is expressed in radians, αt is the helix angle of the external strand and is expressed in radians, Cste = 1500 N.mm -2 is the code.

[0039] ES’ ≥ 155 N.mm -1 is preferably, and ES’ ≥ 160 N.mm -1 is more preferably.

[0040] The total elongation ratio At of the extracted code is measured in the same way as the total elongation ratio At of the code defined above.

[0041] The extracted code preferably has a diameter D such that D ≤ 6.0 mm, and more preferably has a diameter D such that 5.0 mm ≤ D ≤ 5.5 mm. The diameter D is measured on the code in accordance with ASTM standard D2969-04.

[0042] The weakening coefficient Cfrag' considers the degree of penetration of the polymer matrix into the code through the use of the interstrand penetration coefficient Cp. To calculate this penetration coefficient, a cross-section is formed on the extracted code using a saw. This process is repeated 10 times to obtain 10 cross-sections, and the average penetration coefficient Cp is calculated on these cross-sections. Next, an electron microscope is used to observe the polymer-filled regions of each extracted code, and image processing software is used to quantify the ratio of the non-metallic surface area free of the polymer compound to the surface area filled with the polymer compound in the contact region Sc between the outer and inner strands, as shown in Figure 8. Thus, a well-penetrated code has a penetration coefficient close to 1, and a less-penetrated code has a penetration coefficient close to 0.5.

[0043] The polymer matrix is ​​preferably an elastomer matrix.

[0044] The polymer matrix, which is preferably an elastomer matrix, is based on a polymer compound, which is preferably an elastomer compound.

[0045] A polymer matrix refers to a matrix containing at least one polymer. Therefore, a polymer matrix is ​​based on a polymer compound.

[0046] An elastomer matrix means a matrix containing at least one elastomer. Therefore, a preferred elastomer matrix is ​​based on an elastomer compound.

[0047] The expression "based on ~" should be understood to mean that the compound includes a mixture of various components used and / or the products of situ reactions, some of which can and / or are intended to react with each other at least partially during various stages of the compound's production, and therefore the compound can be fully or partially crosslinked or uncrosslinked.

[0048] A polymeric compound means that the compound contains at least one polymer. Such polymers are preferably thermoplastics such as polyester or polyamide, thermosetting polymers, elastomers such as natural rubber, thermoplastic elastomers, or combinations thereof.

[0049] An elastomer compound means that the compound contains at least one elastomer and at least one other component. Compounds containing at least one elastomer and at least one other component preferably include an elastomer, a crosslinking system and a filler. Compounds that can be used in these plies are conventional compounds for skim coating filamentous reinforcing elements, preferably containing sulfur, stearic acid and zinc oxide, and optionally containing vulcanization accelerators and / or retarders and / or various additives, including diene elastomers such as natural rubber, reinforcing fillers such as carbon black and / or silica, and crosslinking systems such as vulcanizing systems. Adhesion between the metal threads and the matrix in which they are embedded is achieved by a metal coating, such as a layer of brass.

[0050] The characteristic values ​​of the extracted code described in this application are measured on or determined from code extracted from, for example, a polymer matrix of a tire, particularly an elastomer matrix. Therefore, in a tire, for example, the material piece radially outside the code to be extracted is removed so that the code to be extracted, which is at the same radial height as the polymer matrix, can be seen. This removal can be done by peeling it off using a cutter and gripper, or by planing. Next, the end of the code to be extracted is exposed using a knife. Then, the code is pulled out from the matrix, applying a relatively shallow angle so as not to plasticize the code to be extracted. After that, the extracted code is carefully cleaned, for example, using a knife, taking care not to damage the surface of the metal threads, to cut off any remaining polymer matrix locally attached to the code.

[0051] The extracted code is: breaking force: TIFF2023503055000011.tif21153 It is advantageous for Fr' ≥ 24,000 N, preferable for Fr' ≥ 25,000 N, and even more preferable for Fr' ≥ 27,000 N. The breaking force is measured on the extract code according to ASTM standard D2969-04.

[0052] The advantageous features described below apply equally to the code and extraction code defined above.

[0053] αf should ideally be 0° or greater, and preferably 5° or greater.

[0054] αf should ideally be 25° or less, and preferably 20° or less.

[0055] Within this contact angle range of 0° to 25°, the contact area is maximized, allowing the polymer compound to penetrate the code relatively well.

[0056] αt should ideally be 0° or greater, and preferably 5° or greater.

[0057] αt should ideally be 20° or less, preferably 15° or less, and even more preferably 10° or less.

[0058] Within this helical angle range, the contact load between the outer and inner strands is minimized when tension is applied to the cord.

[0059] The metal threads of the cord are advantageously comprised of at least 50%, preferably at least 60%, more preferably at least 70%, of a steel core, where each metal thread of the cord has a composition conforming to NF-EN Standard 10020 September 2000, with a carbon content C > 0.80%, preferably C ≥ 0.82%. Such steel compounds are combinations of non-alloy steel (items 3.2.1 and 4.1 of NF-EN Standard 10020 September 2000), stainless steel (items 3.2.2 and 4.2 of NF-EN Standard 10020 September 2000), and other alloy steels (items 3.2.3 and 4.3 of NF-EN Standard 10020 September 2000). The relatively high carbon content enables the achievement of the mechanical strength of the metal threads of the cord according to the present invention. Furthermore, the manufacturing method of the metal threads could also be modified to increase the mechanical strength of the metal threads, in particular by further work-hardening each metal thread. Modifying the manufacturing method of metal threads requires relatively significant industrial investment, whereas using relatively high carbon content requires no investment. Furthermore, unlike methods that further work-harden metal threads, which significantly reduce their flexural compression durability, using relatively high carbon content allows for the maintenance of the metal thread's flexural compression durability.

[0060] The metal threads of the cord are advantageously comprised of at least 50%, preferably at least 60%, and more preferably at least 70%, a steel core having a composition conforming to NF-EN Standard 10020 of September 2000, with a carbon content of C ≤ 1.20%, and preferably C ≤ 1.10%. The use of excessively high carbon content is, on the one hand, relatively expensive, and on the other hand, reduces the corrosion fatigue resistance of the metal threads.

[0061] d1, d1', d3, and d3' are preferably independent of each other and in the range of 0.25 mm to 0.50 mm, more preferably in the range of 0.30 mm to 0.45 mm, and even more preferably in the range of 0.32 mm to 0.42 mm.

[0062] It is advantageous for the outer layer of the code to be saturated such that the inter-strand distance of the outer strands is strictly less than 20 μm.

[0063] By definition, a saturated layer of a cord is one in which the inter-strand distance of the outer strands is strictly less than 20 μm. The inter-strand distance of the outer layer of the outer strands is defined as the shortest distance that, on average, separates two adjacent circular envelopes inscribed within the outer strands in a cross-section of the cord perpendicular to the main axis of the cord. Thus, the structure of this cord can ensure good structural stability of the outer layer, and the saturation of the outer layer can ensure that the outer layer contains a relatively large number of outer strands and therefore exhibits relatively high breaking strength.

[0064] The strand-to-strand distance E is calculated by subtracting the diameter of the outer strand from the distance between the two centers of two adjacent outer strands, points A and B, as shown in Figure 9.

[0065] It is preferable that all threads in one identical layer of a given (internal or external) strand have substantially the same diameter. It is advantageous for external strands to all have substantially the same diameter. "Substantially the same diameter" means that the threads or strands have the same diameter within the range of industrial tolerances.

[0066] For this purpose, in an orthonormal 2-D reference system, i.e., in the cross-section of the code, if the direction of the horizontal axis with the center of the code at O ​​is OA, then in the case where all the outer strands have substantially the same diameter, the coordinates of the centers of the two strands A and B are A = [Re TE ,0], B=[Re TE It is calculated as ×cos(2π / L),ReTE×sin(2π / L), where L is the number of outer strands, Re TE is the helical radius of each outer strand, expressed in millimeters.

[0067] The helical radius of each outer strand is Re TEIt is calculated using the formula =max(Re_minTE;ReTEunsaturated), where Re_minTE is the winding radius obtained when the layer is supersaturated. This radius is the minimum radius at which all strands make contact: Re_minTE = 1 / [(sin 2 (π / L) / D TE / 2) 2 -cos 2 (π / L) × (2π / pe) 2 ], where L is the number of outer strands, pe is the winding pitch of each outer strand expressed in millimeters, DTE is the diameter of the outer strand (in mm), Re TEunsaturated This corresponds to an unsaturated or strictly saturated structure, Re TEunsaturated =D TI / 2+D TE / 2, where DTI is the diameter of the internal strand in mm, D TE This is the diameter of the outer strand in millimeters.

[0068] The diameter of the outer strand is D TE It is calculated as =2×Re1'+d1'+2×d3'. Here, Re1' is the winding radius of the inner layer of the outer strand. - If the inner layer of the outer strand contains only one internal metal thread, then Re1'=0, - Otherwise, Re1'=1 / [(sin 2 (π / Q') / d1' / 2) 2 -cos 2 (π / Q')×(2π / p1') 2 ] and Here, Q' is the number of metal threads in the inner layer of the outer strand, d1' is the diameter in millimeters of the metal threads in the inner layer of the outer strand, and pitch p1' is the pitch in millimeters of the inner layer of the outer strand.

[0069] Next, AB = [(xb-xa) 2 +(yb-ya) 2 ] 1 / 2The distance AB in the reference frame is calculated using the following formula, and then the strand distance is given by E = AB - D TE The value is calculated in μm units as / cos(αt) × 1000, and D here TE αt = atan(2πReTE / pe) is the diameter of the outer strand, αt = atan(2πReTE / pe) is the helical angle of the outer strand, and pe is the winding pitch of each outer strand, expressed in millimeters.

[0070] In contrast, an unsaturated layer of the code is one in which the distance between strands of the outer strands is 20 μm or more.

[0071] It is advantageous for the outer layer of the inner strand to be desaturated.

[0072] By definition, an unsaturated layer is one in which sufficient space remains between the threads to allow a polymer compound, preferably an elastomer compound, to pass through. An unsaturated layer means that the threads do not touch each other, and sufficient space exists between two adjacent threads to allow the polymer compound, preferably an elastomer compound, to pass through. In contrast, a saturated layer is one in which, for example, each pair of threads in the layer is in contact with each other, and therefore there is no sufficient space between the threads of the layer to allow the polymer compound, preferably an elastomer compound, to pass through.

[0073] By definition, the strand distance of a layer is defined as the shortest distance that, on average, separates two adjacent threads of the layer in a cross-section of the code perpendicular to the main axis of the code.

[0074] The distance between threads in a layer is calculated as follows: The winding radius of the outer layer of the outer strand is, Re3' = Re1' + d1 / 2 + d3 / 2 It is calculated as follows, where Re1' is the winding radius of the inner layer of the outer strand as defined above.

[0075] The inter-thread distance I3' is calculated by subtracting the thread diameter from the distance between the two centers of the metal threads, as shown in Figure 9, and the calculation method is the same as that used for the outer strand. A'=[Re 3’ ,0] B'=[Re 3’ ×cos(2π / N'),Re3'×sin(2π / N')] A'B'=[(xb'-xa')] 2 +(yb'-ya') 2 ] 1 / 2

[0076] Next, this gives us I3'=A'B'-d3' / cos(αC3')×1000, where αC3'=atan(2πR3' / p3') is the helical angle of the outer layer of the outer strand.

[0077] The total SI3' is the sum of the inter-thread distances that separate each pair of adjacent outer threads in the outer layer.

[0078] It is advantageous for the thread spacing between the outer layers of the inner strands to be 5 μm or more. Preferably, the thread spacing between the outer layers of the inner strands is 15 μm or more, more preferably 35 μm or more, even more preferably 50 μm or more, and very preferably 60 μm or more.

[0079] The distance between threads in the outer layer of the inner strand is preferably 100 μm or less.

[0080] It is advantageous for the sum of the inter-thread distances I3 in the inner strands of the outer layer, SI3, to be greater than the diameter d3 of the outer threads of the outer layer.

[0081] It is advantageous that each strand is of the type that is not rubberized in situ. Not rubberized in situ means that each strand is composed of various layers of thread before being assembled with the other strands, and does not contain any polymer compounds, especially elastomer compounds.

[0082] It is advantageous for the outer layer of each outer strand to be desaturated.

[0083] It is advantageous for the distance between threads in the outer layer of each outer strand to be 5 μm or more. Preferably, the distance between threads in the outer layer of each outer strand is 15 μm or more, more preferably 35 μm or more, even more preferably 50 μm or more, and very preferably 60 μm or more.

[0084] The distance between threads in the outer layer of each outer strand is preferably 100 μm or less.

[0085] It is advantageous for the sum of the inter-thread distances I3' of the outer layer of each outer strand, SI3', to be greater than or equal to the diameter d3' of the outer thread of the outer layer.

[0086] Each internal metal thread in the internal strand preferably has a diameter d1 that is at least as large as the diameter d3 of each external metal thread in the internal strand, and it is preferable that 1.00 ≤ d1 / d3 ≤ 1.20.

[0087] Each internal metal thread in each external strand preferably has a diameter d1' that is greater than or equal to the diameter d3' of each external metal thread in each external strand (TE), and it is preferable that 1.00 ≤ d1' / d3' ≤ 1.20.

[0088] In one embodiment, each internal thread has a diameter d1 or d1' greater than or equal to the diameter d3 or d3' of each external thread. Using diameters such that d1>d3 or d1'>d3' can facilitate the penetration of polymer compounds, such as elastomer compounds, through the outer layer. In another embodiment, where d1=d3 and d1'=d3', it is possible to limit the number of different threads that need to be managed in the production of the code.

[0089] The outer layer of the inner strand is preferably wound around the inner layer of the inner strand in contact with it.

[0090] It is advantageous for L to be 6, 7, or 8, preferred for L to be 6 or 7, and even more preferred for L to be 6.

[0091] It is preferable that K=1 and L=6. In a code where K=1, the largest lateral load is the lateral load exerted by the outer strands on the inner strands.

[0092] The internal strand of the code according to the present invention In one preferred embodiment, Q > 1, preferably Q = 2, 3, or 4. In the case where Q is equal to 1, there is a risk of witnessing the internal threads of the internal strands radially separating from the internal strands and the code under the influence of the repetitive compressive load applied to the code. The presence of multiple (Q > 1) threads in the inner layer of the internal strand reduces this risk, as the compressive load is distributed across multiple threads in the inner layer.

[0093] It is advantageous for N to be 7, 8, 9, or 10, and it is preferable for N to be 8 or 9.

[0094] In the first alternative form, Q=2 and N=7 or 8, with Q=2 and N=7 being preferred.

[0095] In the second alternative form, Q=3 and N=7, 8, or 9, with Q=3 and N=8 being preferred.

[0096] In the third alternative form, Q=4 and N=7, 8, 9, or 10, with Q=4 and N=9 being preferred.

[0097] It is highly advantageous for each internal thread of an internal strand to have a diameter d1 equal to the diameter d3 of each external thread of the internal strand. Therefore, it is preferable to use threads of the same diameter in the inner and outer layers of an internal strand, thereby limiting the number of different threads that need to be managed during code manufacturing.

[0098] External strand of code according to the present invention It is advantageous for N' to be 7, 8, 9, or 10, and it is preferable for N' to be 8 or 9.

[0099] In the first alternative form, Q'=2 and N'=7 or 8, with Q'=2 and N'=7 being preferable.

[0100] In the second alternative form, Q'=3 and N'=7, 8, or 9, with Q'=3 and N'=8 being preferred.

[0101] In the third alternative form, Q'=4 and N'=7, 8, 9, or 10, with Q'=4 and N'=9 being preferable.

[0102] It is highly advantageous for each internal thread of an outer strand to have a diameter d1' equal to the diameter d3' of each external thread of the outer strand. Therefore, it is preferable to use threads of the same diameter in the inner and outer layers of an internal strand, thereby limiting the number of different threads that need to be managed during code manufacturing.

[0103] It is advantageous that Q=4 and N=9, Q'=4 and N'=9, and d1=d3=d1'=d3'.

[0104] Reinforcement product according to the present invention Another subject of the present invention is a reinforcement product comprising a polymer matrix and at least one code or extracted code as defined above.

[0105] This reinforcing product comprises one or more codes according to the present invention embedded in a polymer matrix, and in the case of multiple codes, it is advantageous that the codes are arranged side by side in the principal direction.

[0106] Tire according to the present invention Another subject of the present invention is a tire comprising at least one cord or reinforcing product as defined above.

[0107] Preferably, this tire has a carcass reinforcement fixed within two bead portions, on which a crown reinforcement, which includes at least one cord as defined above and is coupled to the bead portion by two sidewall portions, rests radially, and on which the tread portion rests.

[0108] In one preferred embodiment, the crown reinforcement includes a working reinforcement comprising at least one cord as defined above, and a protective reinforcement sandwiched radially between the tread portion and the working reinforcement.

[0109] This code applies in particular to "heavy vehicles," that is, industrial vehicles selected from heavy vehicles such as subways, buses, road transport vehicles (tanleys, tractors, trailers), off-road vehicles, agricultural vehicles or plant construction vehicles, or other transport or delivery vehicles.

[0110] This tire is preferably intended for construction plant type vehicles. Therefore, the tire has a size such that the diameter of the rim seat to which the tire is intended is 40 inches or larger.

[0111] The present invention also relates to rubber items comprising assemblies according to the present invention, or impregnated assemblies according to the present invention. Rubber items mean any type of rubber item, such as a ball, a non-pneumatic object such as a non-pneumatic tire casing, a conveyor belt, or a track.

[0112] The present invention can be better understood by reading the following embodiments, which are presented merely as non-limiting examples while referring to the drawings. [Brief explanation of the drawing]

[0113] [Figure 1] This is a cross-sectional view of the tire according to the present invention, perpendicular to the circumferential direction. [Figure 2] This is a detailed view of area II in Figure 1. [Figure 3]This is a cross-sectional view of the reinforcing product according to the present invention. [Figure 4] This is a schematic diagram of a cross-section of the cord (50) perpendicular to the cord axis (assuming it is straight and stationary), according to a first embodiment of the present invention. [Figure 5] This is a schematic diagram of a cross-section perpendicular to the axis of the extracted code (50') according to a first embodiment of the present invention (assuming the code is straight and stationary). [Figure 6] This figure is similar to that of Figure 4, showing code (60) according to a second embodiment of the present invention. [Figure 7] Figure 4 is a schematic diagram of the angle αf of code (50). [Figure 8] This is a photograph of code (50) according to the first embodiment of the present invention. [Figure 9] This is a schematic diagram of different geometric parameters of the code. [Modes for carrying out the invention]

[0114] Examples of tires according to the present invention Figures 1 and 2 show the reference frames X, Y, and Z corresponding to the normal axial (X), radial (Y), and circumferential (Z) directions of a tire, respectively.

[0115] The "median circumferential surface" M of the tire is a plane that is perpendicular to the tire's axis of rotation and equidistant from the annular reinforcing structures of each bead.

[0116] Figures 1 and 2 show a tire according to the present invention, indicated by general reference number 10.

[0117] Tire 10 is intended for heavy construction plant vehicles, such as dump trucks. Therefore, tire 10 has dimensions of the 53 / 80R63 type.

[0118] The tire 10 has a crown 12 reinforced by a crown reinforcement 14, two sidewall sections 16, and two bead sections 18, each of which is reinforced by an annular structure, which in this case is a bead thread 20. The crown reinforcement 14 has a tread section 22 mounted radially on it, which is connected to the bead sections 18 by the sidewall sections 16. The carcass reinforcement 24 is fixed to the two bead sections 18 and, in this case, is wrapped around the two bead threads 20 and positioned outward from the tire 20, and includes a turn-up section 26 shown here as being mounted on the wheel rim 28. The carcass reinforcement 24 has the crown reinforcement 14 mounted radially on it.

[0119] The carcass reinforcement 24 includes at least one carcass ply 30 reinforced by radial carcass cords (not shown). The carcass cords are arranged substantially parallel to each other and extend from one bead portion 18 to the other bead portion 18 so as to form an angle of 80° to 90° with the median circumferential plane M (a plane perpendicular to the axis of rotation of the tire, located midway between the two bead portions 18 and passing through the center of the crown reinforcement 14).

[0120] The tire 10 also includes a sealing ply 32 made of elastomer, which is intended to define the radial inner surface 34 of the tire 10 and protect the carcass ply 30 from the diffusion of air from the internal space of the tire 10 (commonly known as an "inner liner").

[0121] The crown reinforcement 14 includes a protective reinforcement 36 positioned radially inward of the tread portion 22, extending from the outside of the tire 10 toward the radially inward side of the tire 10; a working reinforcement 38 positioned radially inward of the protective reinforcement 36; and an additional reinforcement 40 positioned radially inward of the working reinforcement 38. Therefore, the protective reinforcement 36 is positioned radially midway between the tread portion 22 and the working reinforcement 38. The working reinforcement 38 is positioned radially midway between the protective reinforcement 36 and the additional reinforcement 40.

[0122] The protective reinforcement 36 includes first and second protective plies 42, 44, each containing a protective metal cord, the first ply 42 being positioned radially inward of the second ply 44. Optionally, the protective metal cord forms an angle with respect to the circumferential direction Z of the tire equal to at least 10°, preferably in the range of 10° to 35°, and more preferably in the range of 15° to 30°.

[0123] The working reinforcement 38 includes first and second working prisms 46, 48, the first ply 46 being positioned radially inward of the second ply 48. Each ply 46, 48 includes at least one cord 50. Optionally, the working metal cord 50 intersects one working ply with the other working ply, forming an angle with respect to the circumferential direction Z of the tire that is at most equal to 60°, preferably in the range of 15° to 40°.

[0124] The additional reinforcing members 40, also called limiting blocks and intended to partially absorb mechanical expansion stress, include, for example, additional metal reinforcing elements that are themselves well known, forming an angle with respect to the circumferential Z of the tire 10 that is up to 10°, preferably in the range of 5° to 10°, as described in, for example, French Patent No. 2419181 or French Patent No. 2419182.

[0125] Examples of reinforcing products according to the present invention Figure 3 shows a reinforced product according to the present invention, indicated by general reference number 100. The reinforced product 100 includes at least one code 50, which in this example is a plurality of codes 50, embedded in a polymer matrix 102.

[0126] Figure 3 shows the polymer matrix 102 and code 50 within a reference system X, Y, Z where direction Y is radial and directions X and Z are axial and circumferential, respectively. In Figure 3, the reinforcing product 100 is arranged side by side in the main direction X and contains multiple codes 50 that extend parallel to each other within the reinforcing product 100 and are embedded together in the polymer matrix 102. In this example, the polymer matrix 102 is an elastomer matrix based on an elastomer compound.

[0127] Code according to the first embodiment of the present invention Figure 4 shows Code 50 according to the first embodiment of the present invention.

[0128] As can be seen with reference to Figure 5, each protective reinforcing element 43, 45 and each hoop reinforcing element 53, 55, when extracted from the tire 10, are formed by the extraction code 50' described later. In this example, the code 50 is obtained by embedding the protective reinforcing elements 43, 45 and the hoop reinforcing elements 53, 55 into polymer matrices, which are polymer matrices that form the polymer matrices of each protective ply 42, 44 and each hoop layer 52, 54, respectively.

[0129] Code 50 and extracted code 50' are made of metal and are of the multi-strand type, containing two cylindrical layers. Therefore, it will be understood that there are no more or less strands than two layers that make up code 50 or 50'.

[0130] Code 50 or Code 50' includes an inner layer CI of the code, which consists of K ≥ 1 inner strand TI. The outer layer CE consists of L > 1 outer strand TE wound around the inner layer CI of the code. In this particular case, L = 6, 7, or 8, preferably L = 6 or 7, more preferably L = 6, and here L = 6.

[0131] Code 50 represents the fracture energy per unit area: TIFF2023503055000012.tif41155 It holds.

[0132] TIFF2023503055000013.tif21153 That is the case.

[0133] Code 50 also includes a wrapper F (not shown) consisting of a single wrapping thread.

[0134] Extraction code 50' represents the fracture energy per unit area: TIFF2023503055000014.tif48155 It holds. To calculate Cp, for example, using the photograph of code 50' in the composite material in Figure 8, software can be used to determine the ratio of the non-metallic surface area free of the polymer compound to the surface area filled with the polymer compound in the contact zone Scp between the outer and inner strands. Here, the ratio averaged over 10 cross-sections is equal to 0.9.

[0135] TIFF2023503055000015.tif21153 That is the case.

[0136] The outer layers of Code 50 and 50' are saturated. Therefore, the inter-strand distance E of the outer strands is strictly less than 20 μm. Here, E = 0 μm.

[0137] αf is 0° or greater, preferably 5° or greater, and 25° or less, preferably 20° or less. Here, αf = 18.9°.

[0138] αt is 0° or greater, preferably 5° or greater, and 20° or less, preferably 15° or less, and even more preferably 10° or less. Here, αt = 9.1°.

[0139] Code 50 and 50' internal strand TI Each internal strand TI is a two-layer strand, comprising an inner layer C1 composed of 2, 3, or 4 internal metal threads F1, and an outer layer C3 composed of N external metal threads F3 wound around the inner layer C1.

[0140] Here, Q = 4.

[0141] It is advantageous for N to be 7, 8, 9, or 10, and it is preferable for N to be 8 or 9; in this case, N=9.

[0142] The outer layer C3 of each inner strand TI is desaturated. The inter-thread distance of the outer layer of the inner strands is 15 μm or more, more preferably 35 μm or more, even more preferably 50 μm or more, and very preferably 60 μm or more, which is equal to 61 μm here. The sum SI3 of the inter-thread distances I3 of the outer layer is greater than the diameter d3 of the outer threads F3 of the outer layer C3. Here, the sum SI3 = 0.061 × 9 = 0.55 mm, and this value is greater than d3 = 0.40 mm.

[0143] Each internal and external thread in each internal strand TI has diameters d1 and d3, respectively. Each internal metal thread F1 in each internal strand TI has a diameter d1 that is greater than or equal to the diameter d3 of each external metal thread in each internal strand TI, preferably 1.00 ≤ d1 / d3 ≤ 1.20.

[0144] d1 and d3 are independent of each other and range from 0.25 mm to 0.50 mm, preferably from 0.30 mm to 0.45 mm, and more preferably from 0.32 mm to 0.42 mm. Here, d1 = d3 = 0.40 mm.

[0145] Code 50 and 50' external strand TE Each outer strand TE has two layers, including an inner layer C1' composed of Q'=2, 3, or 4 inner metal threads F1', and an outer layer C3' composed of N' outer metal threads F3' wound around the inner layer C1'.

[0146] Here, Q'=4.

[0147] N'=7, 8, 9, or 10, preferably N'=8 or 9, and in this case N'=9.

[0148] The outer layer C3' of each outer strand TE is desaturated. Because the outer layer C3' is desaturated, the inter-thread distance I3' of the outer layer C3' that averages out to separate N' outer threads is 5 μm or more. The inter-thread distance I3' of the outer layer of each outer strand is 15 μm or more, more preferably 35 μm or more, even more preferably 50 μm or more, and very preferably 60 μm or more, which is equal to 61 μm here. The sum SI3' of the inter-thread distances I3' of the outer layer C3' is greater than the diameter d3' of the outer threads F3' of the outer layer C3'. Here, the sum SI3' = 0.061 × 9 = 0.55 mm, and this value is greater than d3' = 0.40 mm.

[0149] Each inner and outer layer C1' and C3' of each outer strand TE is wound in the same direction as the winding direction of the cord and the inner and outer layers C1 and C3 of the inner strand TI. Here, the winding direction of each layer of the cord and the winding direction of the cord itself are Z.

[0150] Each internal thread and external thread of each external strand TE has diameters d1' and d3', respectively. Each internal metal thread F1' of each external strand TE has a diameter d1' that is greater than or equal to the diameter d3' of each external metal thread F3' of each external strand TE, preferably 1.00 ≤ d1' / d3' ≤ 1.20.

[0151] d1' and d3' are independent of each other and range from 0.25 mm to 0.50 mm, preferably from 0.30 mm to 0.45 mm, and more preferably from 0.32 mm to 0.42 mm. Here, d1' = d3' = 0.40 mm.

[0152] Codes 50 and 50' are those where Q=4 and N=9, Q'=4 and N'=9, and d1=d3=d1'=d3'. Here, d1=d3=d1'=d3'=0.40mm.

[0153] The metal threads of the cord consist of at least 50%, preferably at least 60%, more preferably at least 70%, each metal thread having a steel core having a composition conforming to NF-EN Standard 10020 of September 2000, with a carbon content C > 0.80%, preferably C ≥ 0.82%. The metal threads of the cord consist of at least 50%, preferably at least 60%, more preferably at least 70%, each metal thread having a steel core having a composition conforming to NF-EN Standard 10020 of September 2000, with a carbon content C ≤ 1.20%, preferably C ≤ 1.10%. Here, each metal thread consists of a steel core having a composition conforming to NF-EN Standard 10020 of September 2000, with a carbon content C = 1%.

[0154] Each thread has a breaking strength expressed in Rm such that 2500 ≤ Rm ≤ 3100 MPa. The steel used for these threads is called SHT ("Super High Tension") grade. Other threads can also be used, such as lower-grade threads like NT ("Normal Tension") or HT ("High Tension") grade, as well as higher-grade threads like UT ("Super Tension") or MT ("Mega Tension") grade.

[0155] Method for manufacturing code according to the present invention Next, an example of a manufacturing method for the multi-strand cord 50 will be described.

[0156] Each of the internal strands described above is preferably executed inline and sequentially. - First, the first step is to assemble the inner layer C1 at a first assembly point by cable braiding the four internal threads F1 of the inner layer C1 at a pitch p1 in the Z direction, - Next, a second step is to assemble N external threads F3 around Q internal threads F1 of the inner layer C1 in the Z direction at a pitch p3 by cable braiding or twisting to form the outer layer C3 at the second assembly point. - Preferably a final twist balance adjustment step, It is manufactured according to known methods, including [specific method].

[0157] Each of the above-mentioned external strands is preferably executed inline and sequentially. - First, the internal threads F1' of the inner layer C1' with Q'=2, 3, or 4 are assembled in the Z direction at a pitch p1' by cable braiding to form the inner layer C1' at the first assembly point. - Next, a second step is to assemble N' outer threads F3' around Q' internal threads F1' of the inner layer C1' in the Z direction at a pitch p3' by cable braiding or twisting to form the outer layer C3' at the second assembly point, - Preferably a final twist balance adjustment step, It is manufactured according to known methods, including [specific method].

[0158] As is well known to those skilled in the art, "twist balance adjustment" here means eliminating the residual torque applied to each thread of the strand in the intermediate layer, as well as in the outer layer (or restoring the elasticity of the twist).

[0159] The production of the strands is completed after this final twist balancing step. Each strand is wound onto one or more storage reels for storage before the subsequent work of cable braiding the base strands together to obtain a multi-strand cord.

[0160] A method well known to those skilled in the art for producing the multi-strand cord of the present invention is to cable-braid or twist together pre-obtained strands using a cable braiding machine or twisting machine that has been evaluated for assembling strands.

[0161] Therefore, L outer strands TE are assembled around the inner strand TI in the Z direction with a pitch pe to form the cord 50. In some cases, in the final assembly step, a wrapper F is wound around the already obtained assembly in the S direction with a pitch pf.

[0162] Next, Code 50 is incorporated by calendering into a composite fabric formed from a known composite based on natural rubber and carbon black as reinforcing fillers, which is conventionally used in the manufacture of crown reinforcements for radial tires. Basically, this composite contains an elastomer and reinforcing filler (carbon black), as well as antioxidants, stearic acid, spreader, cobalt naphthenate as an adhesion promoter, and finally a vulcanizing agent (sulfur, accelerator, and ZnO).

[0163] The composite fabric reinforced by these cords has an elastomer composite matrix formed from two thin layers of elastomer composite, each with a thickness of 1 mm to 4 mm, overlapping on both sides of the cord. The skim pitch (the spacing between the cords within the elastomer composite fabric) ranges from 4 mm to 8 mm.

[0164] Subsequently, these composite fabrics are used as working plies in the crown reinforcement during the tire manufacturing process, a step that is also well known to those skilled in the art.

[0165] Code according to a second embodiment of the present invention Figure 6 shows code 60 according to a second embodiment of the present invention.

[0166] Unlike the first embodiment described above, the code 60 according to the second embodiment is such that Q=3 and N=8, and Q'=3 and N'=8.

[0167] Table 1 below summarizes the characteristics of various codes 50, 50', and 60.

[0168] [Table 1]

[0169] Official Exam Evaluation of fracture energy per unit area Various parallel codes and prior art codes were simulated.

[0170] Table 2 summarizes the characteristics of the control code T1 and the characteristics of the prior art code EDT (Example 8 of International Publication No. 2016 / 017655).

[0171] [Table 2]

[0172] Tables 1 and 2 show that codes 50, 50', and 60 exhibit improved fracture energy per unit area compared to the prior art codes EDT and EDT'. Specifically, codes EDT and EDT' have relatively high weakening coefficients but relatively low fracture forces, and therefore their fracture energy per unit area is insufficient to reduce the number of broken and perforated tire cords. Accordingly, the cords according to the present invention have a sufficiently high fracture energy per unit area ES ≥ 150 N.mm² to overcome these disadvantages. -1 It holds.

[0173] The present invention is not limited to the embodiments described above. [Explanation of Symbols]

[0174] 50 Codes CE Code Outer Layer Inner layers of CI code C1 Inner layer of the internal strand C1' Inner layer of outer strand C3 Outer layer of the inner strand C3' Outer layer of the outer strand F1 Internal Strand Internal Metal Thread F1' Internal metal threads of the external strands F3 Internal Strand External Metal Thread F3' External metal thread of external strand TE external strand TI internal strand

Claims

1. A two-layer multi-strand cord (50), an inner layer (CI) of said cord consisting of K=1 inner strand (TI) having two layers (C1, C3), The two layers (C1, C3) are an inner layer (C1) consisting of Q=2, 3 or 4 internal metal threads (F1); an outer layer (C3) consisting of N outer metal threads (F3) of diameter d3 wound around said inner layer (C1); Including, The two-layer multi-strand cord (50) is an outer layer (CE) of the cord consisting of L>1 outer strands (TE) wound around the inner layer (CI) of the cord, the outer layer (CE) having two layers (C1', C3'), The two layers (C1', C3') are an inner layer (C1') consisting of Q'=2, 3 or 4 internal metal threads (F1'); an outer layer (C3) consisting of N' outer metal threads (F3') of diameter d3' wound around said inner layer (C1'); Including, The cord (50) has a breaking energy per unit area ES≧155 N.mm -1 having where: is the total breaking force in Newtons of Nc threads, Nc=Q+N+L×(Q′+N′) is the total number of metal threads; D is the diameter of the cord in mm, is the sum of the total elongation of the Nc threads and is dimensionless; Cfrag is the dimensionless weakening factor of the code (50), where: d3 and d3' are expressed in mm; αf is the contact angle between the outer metal thread (F3) of the inner strand (TI) and the outer metal thread (F3′) of the outer strand (TE), expressed in radians; αt is the helix angle of each outer strand (TE) expressed in radians; Cste=1500N. mm -2 and Each thread has a breaking strength, in Rm, such that 2500≦Rm≦3100 MPa. A code (50).

2. ES≧160N. mm -1 That is, The cord (50) of claim 1.

3. Breaking force such that Fr≧25,000 N: Showing, The cord (50) of claim 1.

4. An extraction cord (50') extracted from a polymer matrix, an inner layer (CI) of said cord consisting of K=1 inner strand (TI) having two layers (C1, C3), The two layers (C1, C3) are an inner layer (C1) consisting of Q=2, 3 or 4 internal metal threads (F1); an outer layer (C3) consisting of N outer metal threads (F3) of diameter d3 wound around said inner layer (C1); Including, The extraction code (50') is an outer layer (CE) of the cord consisting of L>1 outer strands (TE) wound around the inner layer (CI) of the cord, the outer layer (CE) having two layers (C1', C3'), The two layers (C1', C3') are an inner layer (C1') consisting of Q'=2, 3 or 4 internal metal threads (F1'); an outer layer (C3) consisting of N' outer metal threads (F3') of diameter d3' wound around said inner layer (C1'); Including, The extraction cord (50') has a breaking energy ES'≧150 N.mm -1 having where: is the total breaking force in Newtons of Nc threads, Nc=Q+N+L×(Q′+N′) is the total number of metal threads; D is the diameter of the cord in mm, is the sum of the total elongation of the Nc threads and is dimensionless; Cfrag' is the dimensionless weakening factor of the cord (50'), where: Cp is the permeability coefficient of the cord, d3 and d3' are expressed in mm; αf is the contact angle between the outer metal thread (F3) of the inner strand (TI) and the outer metal thread (F3′) of the outer strand (TE), expressed in radians; αt is the helix angle of the outer strand (TE) expressed in radians; Cste=1500N. mm -2 and Each thread has a breaking strength, in Rm, such that 2500≦Rm≦3100 MPa. A cord (50') characterized in that

5. The cord (50, 50') according to claim 1 or 4, wherein αf is equal to or greater than 0° and αf is equal to or less than 25°.

6. αt is equal to or greater than 0° and αt is equal to or less than 20°; A cord (50, 50') according to claim 1 or 4.

7. The outer layer (C3) of the inner strand (TI) is desaturated; A cord (50, 50') according to claim 1 or 4.

8. The outer layer C3' of each outer strand (TE) is desaturated; A cord (50, 50') according to claim 1 or 4.

9. A polymer matrix (102) and at least one extraction code (50') according to claim 4. A reinforced product (100).

10. It comprises at least one extraction cord (50') according to claim 4 or a reinforcement product according to claim 9. A tire (10).

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