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    • 专利摘要:
    The invention relates to a tire comprising a crown reinforcement consisting of at least three reinforcement element working crown layers, wherein at least two layers of rubber compound Ci are disposed between the ends of the at least three working crown layers. . According to the invention, in a meridian plane, the thickness of said at least three working crown layers measured in the equatorial plane is less than 5 mm, the reinforcing elements of said at least three working crown layers being metal wires units of diameter less than 0.50 mm, the distance between the reinforcing elements, measured as normal to the direction of the mean line of the wire, being strictly less than 1 mm and the axial width of each of the at least three layers of being greater than 60% of the axial width of the tread, the modulus of elasticity under tension at 10% elongation of at least one layer Ci being less than 8 MPa and the maximum value of tan (δ) , denoted tan (δ) max, of said at least one layer Ci being less than 0.100.
    公开号:FR3036315A1
    申请号:FR1554394
    申请日:2015-05-18
    公开日:2016-11-25
    发明作者:Claudia Navarro-Losada；Aurore Lardjane；Jean Francois Parmentier；Vincent Martin；Nathalie Salgues
    申请人:Michelin Recherche et Technique SA Switzerland ；Compagnie Generale des Etablissements Michelin SCA；Michelin Recherche et Technique SA France；
    IPC主号:
    专利说明:

    [0001] The present invention relates to a pneumatic tire with a radial carcass reinforcement and more particularly to a tire intended to equip vehicles carrying heavy loads, such as, for example, trucks. The invention relates to a pneumatic tire with a radial carcass reinforcement. , tractors, trailers or road buses. [0002] In general, in heavy-vehicle tires, the carcass reinforcement is anchored on both sides in the bead zone and is radially surmounted by a crown reinforcement consisting of at least two layers, superimposed and formed of son or parallel cables in each layer and crossed from one layer to the next in making with the circumferential direction angles between 10 ° and 45 °. Said working layers, forming the working armature, can still be covered with at least one so-called protective layer and formed of advantageously metallic and extensible reinforcing elements, called elastic elements. It may also comprise a layer of low extensibility wires or metal cables forming with the circumferential direction an angle of between 45 ° and 90 °, this so-called triangulation ply being radially located between the carcass reinforcement and the first ply of plywood. so-called working top, formed of parallel wires or cables having angles at most equal to 45 ° in absolute value. The triangulation ply forms with at least said working ply a triangulated reinforcement, which presents, under the different stresses it undergoes, few deformations, the triangulation ply having the essential role of taking up the transverse compression forces of which the object all the reinforcing elements in the area of the crown of the tire. Cables are said to be inextensible when said cables have under a tensile force equal to 10% of the breaking force a relative elongation at most equal to 0.2%. Cables are said elastic when said cables have under tensile force equal to the breaking load a relative elongation of at least 3% with a maximum tangent modulus of less than 150 GPa. [0005] Circumferential reinforcing elements are reinforcing elements which make angles with the circumferential direction in the range + 2.5 °, -2.5 ° around 0 °. [0006] The circumferential direction of the tire, or longitudinal direction, is the direction corresponding to the periphery of the tire and defined by the rolling direction of the tire. [0007] The transverse or axial direction of the tire is parallel to the axis of rotation of the tire. The radial direction is a direction intersecting the axis of rotation of the tire 10 and perpendicular thereto. The axis of rotation of the tire is the axis around which it rotates in normal use. A radial or meridian plane is a plane which contains the axis of rotation of the tire. The circumferential mid-plane, or equatorial plane, is a plane perpendicular to the axis of rotation of the tire and which divides the tire into two halves. As regards the metal wires or cables, the measurements of force at break (maximum load in N), tensile strength (in MPa) and elongation at break (total elongation in%) are carried out in tension according to the ISO 6892 standard of 1984. [0013] As regards the rubber compositions, the modulus measurements are made in tension according to the AFNOR-NFT-46002 standard of September 1988: the second elongation is measured ( ie, after an accommodation cycle) the nominal secant modulus (or apparent stress, in MPa) at 10% elongation (normal conditions of temperature and hygrometry according to the AFNOR-NFT-40101 standard of December 1979). Some current tires, called "road", are intended to run at high average speeds and on longer and longer journeys, due to the improvement of the road network and the growth of the network. highway in the world. The set of conditions under which such a tire is called to roll, undoubtedly allows an increase in the number of kilometers traveled, the wear of the tire being less. This increase in life in terms of mileage, combined with the fact that such conditions of use are likely to result, under heavy load, in relatively high peak temperatures, necessitate an at least proportional increase in endurance potential. of the frame crown of the tires. Indeed, there are constraints at the level of the crown reinforcement and more particularly shear stresses between the crown layers which, in the case of a too high rise in the operating temperature at the ends. of the axially shorter crown layer, result in the appearance and propagation of cracks in the rubber at said ends. The same problem exists in the case of edges of two layers of reinforcement elements, said other layer not necessarily being radially adjacent to the first. In order to improve the endurance of the crown reinforcement of the tires, the French application FR 2 728 510 proposes to have, on the one hand, between the carcass reinforcement and the reinforcement work web. radially closest to the axis of rotation, an axially continuous ply formed of non-extensible metal ropes forming with the circumferential direction an angle at least equal to 60 °, and whose axial width is at least equal to axial width of the shortest working crown ply, and secondly between the two working crown plies an additional ply formed of metal elements, oriented substantially parallel to the circumferential direction. In addition, the French application WO 99/24269 proposes, on either side of the equatorial plane and in the immediate axial extension of the additional ply 25 of reinforcement elements substantially parallel to the circumferential direction, to couple , over a certain axial distance, the two working crown plies formed of reinforcing elements crossed from one ply to the next one and then decoupling them with rubber mixing profiles at least over the remainder of the width common to said two sheets of work. The layer of circumferential reinforcing elements is usually constituted by at least one wire rope wound to form a turn whose laying angle relative to the circumferential direction is less than 8 °. The cables initially manufactured are coated with a rubbery mixture before being put in place. This rubbery mixture then penetrates the cable under the effect of pressure and temperature during the baking of the tire. The results thus obtained in terms of endurance and wear during prolonged runs on high speed roads are most often satisfactory. However, it appears that under certain driving conditions, some tires sometimes show a more pronounced wear on part of their tread. This phenomenon is accentuated when the width of the tread increases. In addition, whatever the solutions envisaged as presented above, the presence of a layer of additional reinforcing elements leads to a greater mass of the tire and to greater manufacturing costs for the tires. WO 10/069676 proposes a layer of circumferential reinforcing elements distributed in a variable pitch. According to the chosen steps, more spaced in the central and intermediate portions of the layer of circumferential reinforcing elements, it is possible to produce tires whose performance in terms of endurance is satisfactory with improved wear performance. . In addition, with respect to a tire comprising a layer of circumferential reinforcing elements distributed in a constant pitch, it is possible to reduce the mass and the cost of such tires, although it is necessary to fill the absence of elements. reinforcement by polymeric masses. An object of the invention is to provide tires for "heavy-duty" vehicles whose endurance and wear performance are maintained or even improved for road use whatever the conditions of use. use, whose mass is further reduced compared to that of the tires as described above and whose performance in terms of rolling resistance is improved to contribute to lower fuel consumption by vehicles equipped with such tires. This object is achieved according to the invention by a radial carcass reinforcement tire for a heavy vehicle type vehicle comprising a crown reinforcement comprising at least three reinforcing element working crown layers, crossed over. from one layer to another by making with the circumferential direction angles between 5 10 ° and 45 °, itself capped radially of a tread, said tread being joined to two beads via two flanks, at least two layers of rubber mix C 1 being disposed between the ends of said at least three working crown layers, in a meridian plane, the thickness of said at least three working crown layers measured in the equatorial plane being less than 10 5 mm, the reinforcement elements of said at least three working crown layers being unit metal wires of diameter less than 0.50 mm, the distance between the reinforcing elements, measured according to the normal to the direction of the mean line of the wire, being strictly less than 1 mm, the axial width of each of said at least three working crown layers being greater than 60% of the axial width of the tread, the modulus of elasticity under tension at 10% elongation of at least one layer Ci of rubber mix is less than 8 MPa and the maximum value of tan (8), noted tan ( 5). ,, of said at least one layer Ci is less than 0.100. Preferably, according to the invention, in a meridian plane, the thickness of said at least three working crown layers measured in the equatorial plane is less than 3.5 mm. Also preferably according to the invention, the distance between the reinforcing elements, measured according to the normal to the direction of the average line of the wire, is less than 0.5 mm. [0026] More preferably according to the invention, the axial width of each of said at least three working crown layers is greater than 80 and preferably less than 95% of the axial width of the tread. The axial widths of the reinforcing element layers are measured on a cross section of a tire, the tire is therefore in a non-inflated state. The axial width of the tread is measured between two shoulder ends when the tire is mounted on its service rim and inflated to its nominal pressure. [0029] A shoulder end is defined in the area of the shoulder of the tire by the orthogonal projection on the outer surface of the tire of the intersection of the tangents to the surfaces of an axially outer end of the tire strip. bearing (top of the sculptures) on the one hand and the radially outer end of a flank on the other. [0030] The tan loss factor (8) is a dynamic property of the rubbery mixture layer. It is measured on a viscoanalyzer, known under the trade name "Metravib VA4000", according to ASTM D 5992-96. The response of a sample of vulcanized composition (cylindrical specimen 2 mm thick and 78 mm 2 in section), subjected to a sinusoidal stress in alternating simple shear, at the frequency of 10 Hz, at a temperature of 100 °, is recorded. vs. A strain amplitude sweep of 0.1 to 50% (forward cycle) is performed, followed by 50% to 1% (return cycle). For the return cycle, the maximum value of tan (8) observed, noted tan (8), is indicated. [0031] The rolling resistance is the resistance that appears when the tire is rolling. It is represented by the hysteretic losses related to the deformation of the tire during a revolution. The frequency values related to the revolution of the tire 20 correspond to values of tan (8) measured between 30 and 100 ° C. The value of tan (8) at 100 ° C thus corresponds to an indicator of the rolling resistance of the rolling tire. [0032] It is still possible to estimate the rolling resistance by measuring energy losses by rebound energy samples imposed at temperatures of 60 ° C and expressed as a percentage. Advantageously according to the invention, the loss at 60 ° C, denoted P60, said at least one layer of rubber mix Ci is less than 20%. [0034] Said at least two layers of rubber compound Ci make it possible to obtain a decoupling of the two working crown layers respectively at their contact in order to distribute the shear stresses over a greater thickness. These shear stresses occur in particular due to circumferential stresses during passage into the contact area. Within the meaning of the invention, the coupled layers are layers whose respective reinforcing elements are radially separated from one another by the mere presence of the calendering layers of said layers. In other words, coupled layers are in contact with each other. The most common tire designs provide layers of rubber mixture disposed between the ends of the working crown layers 10 with tensile modulus of elasticity at 10% elongation greater than 8.5 MPa, in particular to limit the shear stresses between the ends of the working crown layers, the circumferential stiffnesses of said working crown layers being zero at their end. Such modules, which are often even greater than 9 MPa, make it possible to avoid the primers and crack propagation in the rubber mixes at the ends of said working crown layers and more particularly at the end of the working layer. more narrow. [0037] Preferably, according to the invention, the crown reinforcement comprises four working crown layers of reinforcement elements and three layers of rubber mix C1, C2, C3 are respectively disposed between the ends of said four top layers. the thickness of said four working crown layers measured in the equatorial plane being less than 5 mm. More preferably according to the invention, the tensile modulus of elasticity at 10% elongation of the three layers of rubber mix C1, C2, C3 are less than 8 MPa and the maximum values of tan (8), noted tan (5). ,, said three layers of rubber mix Cl, C2, C3 are less than 0.100. The results obtained with tires according to the invention have indeed shown that at least equivalent performance in terms of endurance and wear, the tires according to the invention have a lower mass and therefore costs reduced manufacturing. The inventors have demonstrated that this lightening of the tire is related to a decrease in the thickness of the crown reinforcement due to the reduction of the diameter of the reinforcement elements of the working layers. This reduction in the diameter of the reinforcing elements is associated with reduced polymer compound thicknesses compared to those of the usual tires and thus an overall thickness of the crown reinforcement lower than that of the usual tires despite the presence of four top layers. working. The inventors have in particular been able to demonstrate that it was possible to reduce the distances between the reinforcing elements within the same working crown layer with respect to more usual designs without harming the properties of the endurance of the tire. It is indeed usual to maintain a minimum distance between the reinforcing elements of the same working layer to limit the phenomena of propagation of cracks from one element to another. The inventors believe that the presence of at least three working layers 15 reduces the risk of cracks appearing at the ends of the working layers because of the distribution of the stresses between the different pairs of working layers submitted. to cleavage effects. This reduction of the crack initiation thus leads to the possibility of reducing the distances between the reinforcing elements. This reduction in the distances between the reinforcing elements of the same working layer contributes to the reduction of the volume of polymer mixture and thus promotes the reduction of the mass of the tire. Furthermore, the distance between the reinforcing elements, defined according to the invention, associated with the number of working crown layers make it possible to retain properties of circumferential rigidity similar to those of a tire of more conventional design. At the shoulders of the tire, the circumferential stiffness imparted by the crown reinforcement is even greater than that obtained with conventional tires. The inventors believe that once again the presence of at least three working layers, leading to a distribution of stresses between the different pairs of working layers subjected to cleavage effects and therefore to a reduction of the stresses. between each pair of working layers, makes it possible to limit the relative displacements of two working layers forming an adjacent pair and thus ensures an efficient coupling as close as possible to the ends of said working layers. The inventors have been able to demonstrate that the presence of at least three working layers makes it possible to maintain performance, particularly in terms of endurance but also in terms of satisfactory wear, with a modulus of elasticity under tension. 10% elongation of at least one layer Ci less than 8 MPa. The inventors have also been able to demonstrate that the cohesion of said at least one Ci layer, when it has a modulus of elasticity under tension at 10% elongation less than 8 MPa, remains satisfactory. For the purposes of the invention, a cohesive rubbery mixture is a rubbery mixture particularly resistant to cracking. The cohesion of a mixture is thus evaluated by a fatigue cracking test performed on a specimen "PS" (pure shear).
    [0002] It consists in determining, after notching the specimen, the crack propagation speed "Vp" (nm / cycle) as a function of the energy release rate "E" (J / m2). The experimental area covered by the measurement is in the range -20 ° C and + 150 ° C in temperature, with an air or nitrogen atmosphere. The biasing of the specimen is a dynamic displacement imposed amplitude ranging between 0.lmm and 10mm in the form of impulse type loading (tangential "haversine" signal) with a rest time equal to the duration of the pulse; the frequency of the signal is of the order of 10 Hz on average. The measurement comprises 3 parts: - An accommodation of the specimen "PS" of 1000 cycles at 27% deformation. - an energetic characterization to determine the law "E" = f (deformation). The energy recovery ratio "E" is equal to W0 * h0, with WO = energy supplied to the material per cycle and per unit volume and h0 = initial height of the test piece. The exploitation of acquisitions "force / displacement" thus gives the relation between "E" and the amplitude of the solicitation. 3036315 -10- - The cracking measurement, after notching of the "PS" test piece. The information collected leads to determining the propagation velocity of the crack "Vp" as a function of the imposed stress level "E". The inventors have in particular demonstrated that the presence of at least three working layers contributes to a lesser evolution of the cohesion of said at least one layer Ci. In fact, the most usual tire designs comprising in particular layers of rubber mixture disposed between the ends of the working crown layers with tensile modulus of elasticity at 10% elongation greater than 8.5 MPa, lead to a change in the cohesion of said layers of rubber mix disposed between the ends layers of working top, the latter tending to weaken. The inventors find that the presence of at least three working layers which limit the displacements between the ends of the working crown layers associated with a maximum value of tan (δ) of at least one layer Ci less than 0.100 leads to a the cohesion of said at least one layer Ci is small because of a limitation of temperature increases. The inventors thus consider that the cohesion of said at least one layer Ci, which is smaller than that which exists in the more usual tire designs, is satisfactory in the design of the tire according to the invention. The inventors further note that three layers C1, C2, C3 of rubber mix associated with four working layers having a tensile modulus of elasticity at 10% elongation less than 8 MPa and a maximum value of tan ( 8), noted tan (5) 'less than 0.100 have improved rolling resistance performance while maintaining satisfactory endurance and wear properties. The inventors have further demonstrated that the greater circumferential stiffness at the shoulders makes it possible to improve the properties of the tire in terms of wear. Indeed, the appearance of wear inhomogeneities between the center and the edge of the tread appearing under certain driving conditions is reduced compared to what can be observed on more usual designs. The reduction in the diameters of the reinforcing elements of the working layers further makes it possible to reduce the sensitivity of the tire to the aggressions of the tread, the overall architecture being more flexible than with tires. more usual. According to a preferred embodiment of the invention, said at least one layer Ci of rubber compound is an elastomeric mixture based on natural rubber or synthetic polyisoprene, predominantly with cis-1,4 linkages and optionally with at least one other diene elastomer, the natural rubber or the synthetic polyisoprene in case of cutting being present at a majority rate with respect to the rate of the other diene elastomer (s) used and a reinforcing filler constituted: a) with carbon black of BET specific surface area greater than 60 m 2 / g, 10 i. used at a rate of between 20 and 40 phr when the Black Structure Index (COAN) is greater than 85, ii. employed at a rate of between 20 and 60 phr when the black structure index (COAN) is less than 85; (b) with carbon black with a BET specific surface area of less than 60 m 2 / g, whatever its structure number, employed at a level of between 20 and 80 phr, and preferably between 30 and 50 phr, c) either with a white filler of silica and / or alumina type having SiOH and / or AlOH surface functions chosen from the group formed by the precipitated or pyrogenic silicas, the aluminas or aluminosilicates or else the modified carbon blacks in progress or after the BET surface area synthesis of between 30 and 260 m 2 / g employed at a rate of between 20 and 80 phr, and preferably between 30 and 50 phr, d) either by a cut of carbon black described in (a) and / or carbon black described in (b) and / or a white charge described in (c) , in which the overall loading rate is between 20 and 80 phr, and of between 40 and 60 pce. BET specific surface measurement is carried out according to the method of BRUNAUER, EMMET and TELLER described in "The Journal of the American Chemical Society", vol. 60, page 309, February 1938, corresponding to standard NFT 45007 of November 1987. The structure index of black COAN (Compressed Oil Absorption Number) is measured according to the ASTM D3493 standard. In the case of using a clear charge or a white charge, it is necessary to use a coupling and / or covering agent chosen from agents known to those skilled in the art. Examples of preferential coupling agents that may be mentioned are sulphurised alkoxysilanes of the bis (3-trialkoxysilylpropyl) polysulfide type, and of these, in particular, bis (3-triethoxysilylpropyl) tetrasulfide marketed by the company DEGUSSA under the Si69 denominations for pure liquid product and X50S for solid product (50/50 by weight blend with N330 black). Examples of coating agents that may be mentioned are a fatty alcohol, an alkylalkoxysilane such as hexadecyltrimethoxy or triethoxysilane respectively marketed by DEGUSSA under the names Sil16 and Si216, diphenylguanidine, a polyethylene glycol, an optionally modified silicone oil. by OH or alkoxy functions. The coating and / or coupling agent is used in a weight ratio relative to 1/100 and 20/100 loading, and preferably between 2/100 and 15/100 when the clear charge represents the totality. of the reinforcing filler and between 1/100 and 20/100 when the reinforcing filler is constituted by a cutting of carbon black and clear charge. [0057] Other examples of reinforcing fillers having the morphology and the SiOH and / or AlOH surface functions of the silica and / or alumina materials previously described and which can be used according to the invention as partial or total replacement thereof. here, the modified carbon blacks may be mentioned either during the synthesis by addition to the feed oil of the oven of a silicon and / or aluminum compound or after synthesis by adding, to an aqueous suspension of carbon black in a solution of silicate and / or sodium aluminate, an acid so as to at least partially cover the surface of the carbon black of SiOH and / or A10H functions. As non-limiting examples of this type of carbonaceous feedstock with SiOH and / or A10H functions at the surface, mention may be made of the CSDP type feeds described in Conference No. 24 of the ACS Meeting, Rubber Division, Anaheim, California, May 6-9. 1997 as well as those of the patent application EP-A-0 799 854. [0058] When a clear filler is used as the only reinforcing filler, the hysteresis and cohesion properties are obtained using a precipitated or pyrogenic silica, or a precipitated alumina or even a BET surface area aluminosilicate of between 30 and 260 m 2 / g. Nonlimiting examples of this type of filler are silicas KS404 from Akzo, Ultrasil VN2 or VN3 and BV3370GR from Degussa, Zeopol 8745 from Huber, Zeosil 175MP or Zeosil 1165MP from Rhodia, HI-SIL 2000 from the PPG Company, etc. Among the diene elastomers that can be used in a blend with natural rubber or a synthetic polyisoprene with a majority of cis-1,4 linkages, mention may be made of a polybutadiene ( BR) preferably with a majority of cis-1,4 linkages, a styrene-butadiene copolymer (SBR) solution or emulsion, a butadiene-isoprene copolymer (BIR) or even a styrene-butadiene-isoprene terpolymer (SBIR). These elastomers may be modified elastomers during polymerization or after polymerization by means of branching agents such as divinylbenzene or starch agents such as carbonates, halogenotins, halosilicons or else by means of agents. functionalization leading to grafting on the chain or at the end of the chain of oxygen functions carbonyl, carboxyl or an amine function such as for example by the action of dimethyl or diethylamino benzophenone. In the case of blends of natural rubber or synthetic polyisoprene with a majority of cis-1,4 linkages with one or more of the diene elastomers mentioned above, the natural rubber or synthetic polyisoprene is preferably used at a rate of majority and more preferentially at a rate greater than 70 phr. According to this preferred embodiment of the invention, a lower modulus of elasticity is generally accompanied by a lower viscous modulus G ", this evolution 25 being favorable to a reduction in rolling resistance. Advantageously according to the invention, to obtain satisfactory circumferential stiffnesses, whatever the rolling conditions, the diameter of the unitary metal wires of the four working crown layers is greater than or equal to 0.25 mm. [0062] Advantageously according to the invention, the stiffness per unit width of each of the working crown layers is between 35 and 70 daN / mm. The stiffness per unit width of a layer of reinforcement elements is determined from the measurements made on the reinforcing elements and the density of reinforcement elements of the layer, itself defined by the number of elements of r The density measurement is performed by visually counting the number of threads present on a sample of undistorted fabric with a width of 10 cm. The number of counted yarns is directly the density value of the yarn / dm fabric. According to a preferred embodiment of the invention, in particular to optimize the gains in mass of the tire, a working crown layer of reinforcing elements comprising two calendering layers between which the reinforcing elements are positioned, the calender thickness measured in a radial direction on either side of a reinforcing element is less than 0.30 mm. On a tire, the measurement of the calender thickness is obtained by halving the distance between the reinforcing elements of two layers of reinforcement elements in contact with each other. More preferably according to the invention, the average angle formed by the reinforcing elements of said at least two working layers with the circumferential direction is less than 30 °. Such angle values further limit the relative displacements of two working layers due to greater circumferential rigidity. The layers of rubber mixture Ci arranged between the ends of two working crown layers may be identical or may have thicknesses measured in the radial direction at the end of the narrowest layer varying from a pair of layers. working summit to another. According to a first embodiment of the invention in the case of four working crown layers, the two working crown layers radially between a radially innermost working crown layer and a crown top layer. radially outermost work axially are narrower than the two radially innermost and radially outermost working crown layers. The radially innermost working crown layer is then advantageously the axially widest layer 3036315 - 15 -. This first embodiment of the invention promotes less heat dissipation at the shoulder area of the tire. According to a second variant embodiment of the invention, in the case of four working crown layers, the two radially innermost and radially outermost working crown layers are axially narrower than the two radially working top between the radially innermost working crown layer and the radially outermost working crown layer. This second embodiment is particularly relevant for limiting damage due to sidewalk impacts. That is, the working crown layer adjacent to the radially innermost layer is the axially widest layer; such a configuration makes it possible to move the ends of the working layers away from the impact zone. That is, the working crown layer adjacent to the radially outermost layer is the axially widest layer; such a configuration then allows to move the ends subjected to the impact of the carcass reinforcement that could be impacted. According to other embodiments of the invention in the case of four working crown layers, a working crown layer radially inner or outer to the other working crown layers and a working crown layer radially between the radially inner and outer working crown layers are axially wider than the other two working crown layers. According to an alternative embodiment of the invention, the modulus of elasticity under tension at 10% elongation of at least one calendering layer of at least one working crown layer is less than 8, 5 MPa and the maximum value of tan (8), denoted tan (5). ,, of said at least one calender layer of at least one working crown layer is less than 0.100. [0072] Usually, the tensile modulus of elasticity at 10% elongation of the calendering layers of the working crown layers is greater than 10 MPa. Such elastic moduli are required to make it possible to limit the compressing of the reinforcing elements of the working crown layers, especially when the vehicle is following a winding path, when maneuvering in the car parks or during the passage of 30 rounds. points. Indeed, the shears along the axial direction that occur on the tread band in the area of the ground contact surface result in the compression of the reinforcing elements of a top layer. job. The inventors have also been able to demonstrate that the presence of at least three working layers in accordance with the invention allows lower modulus of elasticity without adversely affecting the endurance properties of the tire due to compressions of the reinforcement elements of the working crown layers as previously described. As in the case of the layers of rubber mixture Ci, the use of at least one calendering layer of at least one working crown layer whose modulus of elasticity is less than or equal to 8.5 MPa and whose value tan (8)., Is less than 0.100 will improve the properties of the tire in terms of rolling resistance retaining satisfactory endurance properties. According to a preferred embodiment of the invention, said at least one calendering layer of at least one working crown layer is an elastomeric mixture based on natural rubber or synthetic polyisoprene, mostly with chains. cis-1,4 and optionally at least one other diene elastomer, the natural rubber or the synthetic polyisoprene in the case of cutting being present at a majority rate relative to the rate of the other diene elastomer or diene elastomers used; a reinforcing filler consisting of: a) carbon black with a BET specific surface area greater than 60 m 2 / g, i. used at a rate of between 20 and 40 phr when the Black Structure Index (COAN) is greater than 85, ii. used at a rate of between 20 and 60 phr when the black structure index (COAN) is less than 85, 25 b) or with carbon black with a BET specific surface area of less than 60 m 2 / g, irrespective of its structure number, employed at a level of between 20 and 80 phr, and preferably between 30 and 50 phr, c) either with a white filler of silica and / or alumina type having SiOH and / or AlOH surface functions chosen from the group formed by precipitated or fumed silicas, aluminas or aluminosilicates or alternatively modified carbon blacks in progress or after the BET surface area synthesis of between 30 and 260 m 2 / g employed at a rate comprised between 20 and 80 phr, and preferably between 30 and 50 phr, d) either by a carbon black cutting described in (a) and / or carbon black described in (b) and / or a white charge described in (c), in which the overall charge rate is between 20 and 80 phr, and preferably between 40 and 60 phr. In the case of using a clear charge or a white charge, it is necessary to use a coupling and / or covering agent chosen from agents known to those skilled in the art. Examples of preferential coupling agents that may be mentioned are sulphurised alkoxysilanes of the bis (3-trialkoxysilylpropyl) polysulfide type, and of these, in particular, bis (3-triethoxysilylpropyl) tetrasulfide marketed by DEGUSSA under the Si69 denominations for pure liquid product and X5OS for solid product (50/50 by weight blend with N330 black). Examples of coating agents that may be mentioned are a fatty alcohol, an alkylalkoxysilane such as hexadecyltrimethoxy or triethoxysilane respectively marketed by the company DEGUSSA under the names Sil16 and Si216, diphenylguanidine, a polyethylene glycol, an optionally modified silicone oil. by OH or alkoxy functions. The coating and / or coupling agent is used in a weight ratio with respect to the feed at 1/100 and 20/100, and preferably between 2/100 and 15/100 when the light load represents the totality. of the reinforcing filler and between 1/100 and 20/100 when the reinforcing filler is constituted by a cutting of carbon black and clear charge. Other examples of reinforcing fillers having the morphology and the SiOH and / or AlOH surface functions of the silica and / or alumina type materials previously described and which can be used according to the invention as partial or total replacement thereof are here, the modified carbon blacks may be mentioned either during the synthesis by addition to the feed oil of the oven of a silicon and / or aluminum compound or after synthesis by adding, to an aqueous suspension carbon black in a solution of silicate and / or sodium aluminate, an acid so as to at least partially cover the surface of the carbon black of SiOH and / or A10H functions. As non-limiting examples of this type of carbonaceous fillers with SiOH and / or A10H functions at the surface, mention may be made of the CSDP type charges described in Conference No. 24 of the ACS Meeting, Rubber Division, Anaheim, California. 6-9 May 1997 as well as those of the patent application EP-A-0 799 854. [0078] When a clear filler is used as the only reinforcing filler, the hysteresis and cohesion properties are obtained using a precipitated or pyrogenic silica, or a precipitated alumina or even a BET surface area aluminosilicate of between 30 and 260 m 2 / g. As non-limiting examples of this type of filler, mention may be made of the silicas KS404 from Akzo, Ultrasil VN2 or VN3 and 10 BV3370GR from Degussa, Zeopol 8745 from Huber, Zeosil 175MP or Zeosil 1165MP from Rhodia, HI-SIL 2000 from the PPG Company, etc. Among the diene elastomers that can be used in a blend with natural rubber or a synthetic polyisoprene with a majority of cis-1,4 linkages, mention may be made of a polybutadiene (BR ) preferably with a majority of cis-1,4 linkages, a styrene-butadiene copolymer (SBR) solution or emulsion, a butadiene-isoprene copolymer (BIR) or even a styrene-butadiene-isoprene terpolymer (SBIR). These elastomers may be modified elastomers during polymerization or after polymerization by means of branching agents such as divinylbenzene or starch agents such as carbonates, halogenotins, halosilicons or else by means of agents. functionalization leading to grafting on the chain or at the end of the chain of oxygen functions carbonyl, carboxyl or an amine function such as for example by the action of dimethyl or diethylamino benzophenone. In the case of blends of natural rubber or synthetic polyisoprene with a majority of cis-1,4 linkages with one or more of the diene elastomers mentioned above, the natural rubber or the synthetic polyisoprene is preferably used at a specific rate. majority and more preferentially at a rate greater than 70 phr. Advantageously again according to the invention, the difference between the modulus of elasticity under tension at 10% elongation of a layer Ci and the modulus of elasticity under tension at 10% elongation of said at least one A calender layer of at least one working crown layer in contact with said at least one layer Ci is less than 2 MPa. According to a first embodiment, the modulus of elasticity of the calendering of a working crown layer whose end is in contact with a layer Ci of rubber compound is greater than that of said layer Ci of rubber mix so that the stack of said layers has a modulus of elasticity gradient favorable to the fight against the crack initiation at the end of the narrower working crown layer. According to a second embodiment, the elasticity moduli of the calendering of the working crown layers and that of said rubber compound layer Ci are identical and advantageously the rubber compounds are the same to simplify the industrial conditions. manufacturing of the tire. The tire according to the invention as it has just been described in its alternative embodiments thus has improved rolling resistance compared to conventional tires while maintaining performance in terms of endurance and wear comparable. . In addition, the lower elasticity moduli of the various rubber mixes further make it possible to soften the crown of the tire and thus to limit the risks of attacking the crown and corrosion of reinforcing elements of the reinforcing layers. of summit when for example pebbles are retained in the funds of sculpture. According to one embodiment of the invention, the crown reinforcement is completed by a layer of circumferential reinforcing elements. The presence of a layer of circumferential reinforcing elements is contrary to the lightening of the tire and then shifts the performance compromise between the lightening and the endurance properties of the tire; the layer of circumferential reinforcing elements can make it possible to improve the endurance of the tire for particularly demanding uses. [0087] Preferably, at least one layer of circumferential reinforcing elements is radially arranged between two working crown layers. According to an advantageous embodiment of the invention, the reinforcing elements of at least one layer of circumferential reinforcing elements are metal reinforcing elements having a secant modulus at 0.7% d. elongation of between 10 and 120 GPa and a maximum tangent modulus of less than 150 GPa. According to a preferred embodiment, the secant modulus of the reinforcing elements at 0.7% elongation is less than 100 GPa and greater than 20 GPa, preferably between 30 and 90 GPa and more preferably less than 80 GPa. GPa. Also preferably, the maximum tangent modulus of the reinforcing elements is less than 130 GPa and more preferably less than 120 GPa. The moduli expressed above are measured on a tensile stress versus elongation curve, the tensile stress corresponding to the measured tension, with a pre-tension of 5N, brought back to the metal section of the the reinforcing element. According to a preferred embodiment, the reinforcing elements of at least one layer of circumferential reinforcing elements are metal reinforcing elements having a tensile stress curve as a function of the relative elongation having small slopes. for the low elongations and a substantially constant and strong slope for the higher elongations. Such reinforcing elements of the additional ply are usually referred to as "bi-module" elements. According to a preferred embodiment of the invention, the substantially constant and strong slope appears from a relative elongation of between 0.4% and 0.7%. The various characteristics of the reinforcing elements mentioned above are measured on reinforcing elements taken from tires. Reinforcing elements that are more particularly suitable for producing at least one layer of circumferential reinforcing elements according to the invention are, for example, assemblies of 3 × construction (0.26 + 6 × 0.23) 5.0 / 7.5 SS. Such a cable has a secant module at 0.7% equal to 45 GPa and a maximum tangent modulus equal to 100 GPa, measured on a tensile stress curve as a function of the elongation, the tensile stress corresponding to the voltage measured, with a pre-tension of 5N, brought back to the metal section of the reinforcing element, of 0.98 mm 2 in the case of the example in question. According to a second embodiment of the invention, the circumferential reinforcing elements may be formed of metal elements and cut so as to form sections of length much shorter than the circumference of the least long layer, but preferably greater than 0.1 times said circumference, the cuts between sections being axially offset with respect to each other. More preferably, the tensile modulus of elasticity per unit width of the additional layer is less than the modulus of tensile elasticity, measured under the same conditions, of the most extensible working crown layer. Such an embodiment makes it possible to confer, in a simple manner, on the layer of circumferential reinforcement elements a module which can easily be adjusted (by the choice of intervals between sections of the same row), but in all cases weaker. the module of the layer 15 consisting of the same metallic elements but continuous, the modulus of the additional layer being measured on a vulcanized layer of cut elements, taken from the tire. According to a third embodiment of the invention, the circumferential reinforcing elements are corrugated metal elements, the ratio a / X of the waving amplitude over the wavelength being at most equal to 0. 09. Preferably, the tensile modulus of elasticity per unit width of the additional layer is smaller than the tensile modulus of elasticity, measured under the same conditions, of the most extensible working crown layer. [0098] A preferred embodiment of the invention further provides that the crown reinforcement is completed radially on the outside by at least one additional protective layer of reinforcing elements oriented with respect to the circumferential direction. with an angle between 10 ° and 45 ° and in the same direction as the angle formed by the elements of the working layer which is radially adjacent thereto. According to a first embodiment of the invention, corresponding to usual tire designs, the reinforcing elements of the protective layer are elastic cables. According to a second embodiment of the invention, the reinforcing elements of the protective layer are single metal wires with a diameter of less than 0.50 mm, the distance between the reinforcing elements, measured according to the normal to the direction of the average line of the wire, being strictly less than 1.5 mm. Other details and advantageous features of the invention will emerge below from the description of the exemplary embodiments of the invention with reference to FIGS. 1 to 3 which represent: FIG. 1, a meridian view of a FIG. 2, a meridian view of a diagram of a tire according to a second embodiment of the invention, FIG. 3, a meridian view. of a diagram of a tire according to the prior art. [00102] The figures are not represented in scale to simplify understanding. The figures represent only a half-view of a tire which extends symmetrically with respect to the axis XX 'which represents the circumferential median plane, or equatorial plane, of a tire. In the figures, the tires 1-31, of size 385/55 R 22.5, have an H / S form ratio equal to 0.55, H being the height of the tire 1 on its mounting rim and S its maximum axial width. Said tires 1-31 comprise a radial carcass reinforcement 2-32 anchored in two beads, not shown in the figures. The carcass reinforcement 2-32 is formed of a single layer of wire ropes.
    [0003] They still have a tread 5-35. In FIG. 1, the carcass reinforcement 2 is shrunk in accordance with the invention by a crown reinforcement 4, formed radially from the inside to the outside: a first layer of work 41 formed of metal son oriented at an angle equal to -18 °, - a second working layer 42 formed of metal son oriented at an angle equal to 18 °, 5 - a third working layer 43 formed of metal wires oriented at an angle equal to -18 °, - a protective layer 45 formed of elastic metal cables 6.35, parallel to the metal son of the working layer 43. [00105] The metallic son constituting the elements The reinforcing layers of the three working layers are UHT type wires having a diameter of 0.35 mm. SHT or higher grade yarns could still be used. They are distributed in each of the working layers with a distance between the reinforcing elements, measured according to the normal to the direction of the average line of the wire equal to 0.35 mm. The axial width L41 of the first working layer 41 is equal to 300 mm. The axial width L42 of the second working layer 42 is equal to 320 mm. The axial width L43 of the third working layer 43 is equal to 300 mm. The axial width L44 of the protective layer 44 is equal to 220 mm. The axial width of the tread L5 is equal to 312 mm. The thickness of the three working crown layers measured in the equatorial plane is equal to 2.5 mm and therefore less than 5 mm. The ends of the working layers 41 and 42 are separated by a layer of Cl rubber compound according to the invention. The ends of the working layers 42 and 43 are separated by a layer of rubber mix C2 according to the invention. In FIG. 2, the carcass reinforcement 22 is fretted in accordance with the invention by a crown reinforcement 24, formed radially from the inside to the outside: of a first layer of work 241 formed of metal wires oriented at an angle equal to 18 °, 5 - a second working layer 242 formed of metal wires oriented at an angle equal to -18 °, - a third working layer 243 formed of metal wires oriented at an angle equal to 18 °, a fourth working layer 244 formed of metal wires oriented at an angle equal to -18 °, a protective layer 245 formed of cables. elastic metal 6.35, parallel to the metal son of the working layer 244. [00115] The metal son constituting the reinforcing elements of the four working layers are UHT type wires having a diameter of 0.35 mm. SHT or higher grade yarns could still be used. They are distributed in each of the working layers with a distance between the reinforcing elements, measured according to the normal to the direction of the average line of the wire equal to 0.35 mm. The axial width L241 of the first working layer 241 is equal to 300 mm. The axial width L242 of the second working layer 242 is equal to 320 mm. The axial width L 243 of the third working layer 243 is equal to 300 mm. The axial width L244 of the fourth working layer 244 is equal to 280 mm. The axial width L245 of the protective layer 245 is equal to 220 mm. The axial width of the tread L25 is equal to 312 mm. The thickness of the four working crown layers measured in the equatorial plane is equal to 3.3 mm and therefore less than 5 mm. In accordance with the invention, three layers of rubber mix C 1, C 2, C 3 respectively decouple the ends of the working crown layers 241, 242, 243 and 244. [00124] In FIG. the carcass reinforcement 32 is fretted by a crown reinforcement 34 formed radially from the inside to the outside of: a first triangulation layer 340 formed of unreflected metal cables 9.35 oriented at an angle equal to 50 °, - a first working layer 341 formed of unreflected metal cables 9.35, continuous over the entire width of the web, oriented by an angle equal to 18 °, 10 - a second working layer 342 formed 9.35 unstretchable wire ropes, continuous over the entire width of the ply, oriented at an angle equal to 18 ° and crossed with the metal cables of the layer 341, - a protective layer 343 formed of elastic metal cables 6.35 . The inextensible metal cables 9.35 of the working layers 341 and 342 are distributed in each of the working layers with a distance between the reinforcing elements, measured according to the normal to the direction of the mean line of the thread equal to 1. mm. The axial width L340 of the triangulation layer 340 is equal to 302 mm. The axial width L341 of the first working layer 341 is equal to 318 mm. The axial width L342 of the second working layer 342 is equal to 296 mm. The axial width L343 of the protective layer 343 is equal to 220 mm. The axial width of the tread L35 is equal to 312 mm. The thickness of the three top layers 340, 341, 342 measured in the equatorial plane is equal to 6.5 mm. The cumulative mass of the four working layers 241, 242, 243 and 244 of the tire according to the invention produced in accordance with the representation of FIG. 2, comprising the mass of the metal wires and calendering mixtures, The mass of the tire according to the invention produced in accordance with the representation of FIG. 2 is equal to 61 Kg. [00133] The cumulative mass of the crown layers 340, 341, 342 of the tire produced in accordance with FIG. to the representation of Figure 3, comprising the mass of the metal cables and calendering mixtures, amounts to 12.6 Kg. The mass of the tire produced in accordance with the representation of Figure 3 is equal to 67 Kg. [00134] tests were performed with each of these tires, the tire made according to Figure 3 being the reference tire. [00135] First endurance tests were performed on a test machine requiring each tire to run a straight line at a speed equal to the maximum speed index prescribed for said tire (speed index) under an initial load of 4000 Kg gradually increased to reduce the duration of the test. Other endurance tests were performed on a test machine imposing cyclically a transverse force and a dynamic overload to the tires. The tests were carried out for the tires according to the invention with conditions identical to those applied to the reference tires. [00137] The tests thus carried out have shown that the distances traveled during each of these tests are substantially identical for the tires according to the invention and the reference tires. It therefore appears that the tires according to the invention have substantially equivalent performance in terms of endurance to those of the reference tires. [00138] Other tests have been carried out to evaluate, in real conditions on vehicles, the wear performance of the tires. The driving conditions, in particular the circuit taken, are determined to be representative of a particular type of use, in the circumstance a use of motorway type more penalizing vis-à-vis the irregular wear. At the end of rolling, there is a better regularity of the wear of the tires according to the invention which results in an additional life potential. Moreover, rolling resistance measurements have been carried out. These tests are carried out with tires according to the invention by varying the characteristics of the mixtures of the layers C1, C2, C3, especially their tensile modulus of elasticity at 10% elongation and the tan value (5%). in accordance with the invention. [00141] Other tests are also carried out with tires according to the invention by also varying the characteristics of the mixtures of the calenders of the working layers 41 and 43, in particular their modulus of elasticity under tension at 10% elongation. and the value tan (5) 'according to the invention. The various mixtures used are listed below, expressing for each the modulus of elasticity under tension at 10% elongation as well as the values tan (8). ,,, and P60. Mixture RI Mixture R2 Mixture 1 Mixture 2 Mixture 3 Mixture 4 Mixture 5 NR 100 100 100 100 100 100 100 Black N347 52 50 33 Black N683 44 30 Black N326 47 Silica I65G 46 Antioxidant (6PPD) 1 1.8 1.5 1 2 1 1 Stearic acid 0.65 0.6 0.9 0.65 1 0.65 0.65 Zinc oxide 9.3 9.3 7.5 9.3 8 9.3 9.3 Cobalt salt (AcacCo) 1.12 1.12 1.12 1.1 1.12 1.12 Cobalt salt 4.5 (AbietateCo) Silane on black 8.3 Sulfur 6.1 5.6 4.5 6.1 4.8 6.1 6.1 3036315 - 28- Accelerator DCBS 0.93 0.8 0.8 0.93 0.93 0.93 Accelerator TBBS 1.01 Co-accelerator DPG 1.1 Retarder CTP PVI 0.25 0.15 0.25 0.2 0.25 0.25 MAI ° (MPa) 10.4 8.5 5.99 5.56 7.25 6.16 4.4 tan (8) '' x 0.130 0.141 0.099 The values of the constituents are expressed in phr (parts by weight per hundred parts of elastomeres). first layer C consists of the mixture R2 and the layers of the layers of tr avail consist of the mixture Rl. Different tires according to the invention have been tested. A first series of tires Si according to the invention was made with layers C1, C2, C3 consisting of mixtures 1 to 5, the calendering of the working layers being constituted by the mixture R1. A second series of tires S2 according to the invention was made with layers C1, C2, C3 consisting of mixtures 1 to 5, the calendering of the working layers also consisting of mixtures 1 to 5. Some tires of this series S2 were made with identical mixtures for the first layer C and the calenders of the working layers and others with different mixtures. The results of the measurements are presented in the following table; they are expressed in Kg / t, a value of 100 being attributed to the tire T1. Pneumatic Ti Pneumatic S1 Pneumatic S2 100 99 96
    权利要求:
    Claims (13)
    [0001]
    CLAIMS1 - A radial carcass reinforcement tire for a heavy vehicle comprising a crown reinforcement comprising at least three reinforcing element working crown layers, crossed from one layer to the other, making with the circumferential direction angles between 10 ° and 45 °, itself capped radially with a tread, said tread being joined to two beads by means of two sidewalls, at least two layers of rubber mix Ci being disposed between ends of said at least three working crown layers, characterized in that, in a meridian plane, the thickness of said at least three working crown layers measured in the equatorial plane is less than 5 mm, in that the elements of reinforcements of said at least three working crown layers are unitary wires having a diameter of less than 0.50 mm, in that the distance between the reinforcing elements, measured as normal to the direction of the mean line of the wire, is strictly less than 1 mm, in that the axial width of each of the at least three working crown layers is greater than 60% of the axial width of the tread and in that the modulus of elasticity under tension at 10% elongation of at least one layer Ci is less than 8 MPa and in that the maximum value of tan (8), noted tan (5). ,, of said at least one layer Ci is less than 0.100.
    [0002]
    2 - A tire according to claim 1, characterized in that the diameter of the unit metal son of the four working crown layers is greater than or equal to 0.25 20 mm.
    [0003]
    3 - A tire according to claim 1 or 2, a working crown layer of reinforcing elements comprising two calendering layers between which the reinforcing elements are positioned, characterized in that the calender thickness measured in a radial direction of both sides of a reinforcing element is less than 0.30 mm. 25
    [0004]
    4 - A tire according to one of claims 1 to 3, characterized in that the rigidity per unit width of each of the working crown layers is between 35 and 70 daN / mm.
    [0005]
    5 - A tire according to one of the preceding claims, characterized in that the crown reinforcement comprises four working crown layers of reinforcement elements and in this only three layers of rubber mix Cl, C2, C3 are respectively disposed between the ends of said four working crown layers.
    [0006]
    6 - A tire according to claim 5, characterized in that the tensile modulus of elasticity at 10% elongation of the three layers of rubber mix C1, C2, C3 are less than 8 MPa and that the maximum values of tan (8), noted tan (8). of the three layers of rubber mix C1, C2, C3 are less than 0.100.
    [0007]
    7 - tire according to one of the preceding claims, characterized in that said at least one layer Ci of rubbery mixture is an elastomeric mixture based on natural rubber or synthetic polyisoprene with a majority of sequences cis-1,4 and possibly 10 at least one other diene elastomer, the natural rubber or the synthetic polyisoprene in case of cutting being present at a majority rate with respect to the content of the other diene elastomer (s) used and a reinforcing filler consisting of: either with carbon black of BET specific surface area greater than 60 m 2 / g, 15 i. used at a rate of between 20 and 40 phr when the Black Structure Index (COAN) is greater than 85, ii. used at a rate of between 20 and 60 phr when the black structure index (COAN) is less than 85, or (b) with carbon black with a BET specific surface area of less than 60 m2 / g, irrespective of its index of structure, employed at a level of between 20 and 80 phr, and preferably between 30 and 50 phr, c) either with a white filler of silica and / or alumina type having SiOH and / or AlOH surface functions chosen from group formed by precipitated or pyrogenic silicas, aluminas or aluminosilicates or else carbon blacks in progress or after BET specific surface area synthesis between 30 and 260 m 2 / g employed at a rate of between 20 and 80 phr , and preferably between 30 and 50 phr, d) by a carbon black cutting described in (a) and / or carbon black described in (b) and / or a white charge described in (b). c), in which the overall charge rate is between 20 and 80 phr, and preferably between 40 and 60 phr.
    [0008]
    8 - A tire according to one of the preceding claims, said at least three working crown layers being each formed of reinforcing elements inserted between two layers of calendering rubber mix, characterized in that the modulus of elasticity under tension at 10% elongation of at least one calendering layer of at least one working crown layer is less than 8.5 MPa and in that the maximum value of tan (8), denoted tan (8) max at least one calendering layer of at least one working crown layer is less than 0.100.
    [0009]
    9 - A tire according to claim 8, characterized in that said at least one calender layer of at least one working crown layer is an elastomeric mixture based on natural rubber or synthetic polyisoprene with a majority of cis-1 linkages , 4 and possibly at least one other diene elastomer, the natural rubber or the synthetic polyisoprene in the case of cutting being present at a majority rate relative to the rate of the other diene elastomer or diene elastomers used and a reinforcing agent consisting of: a) carbon black with a BET specific surface area greater than 60 m 2 / g, i. employed at a rate of between 20 and 40 phr when the Black Structure Index (COAN) is greater than 85, ii. used at a rate of between 20 and 60 phr when the black structure index (COAN) is less than 85, or (b) with carbon black with a BET specific surface area of less than 60 m2 / g, irrespective of its index of structure, employed at a level of between 20 and 80 phr, and preferably between 30 and 50 phr, c) either with a white filler of silica and / or alumina type having SiOH and / or AlOH surface functions chosen from the group formed by precipitated or pyrogenic silicas, aluminas or aluminosilicates, or alternatively modified carbon blacks in progress or after the BET specific surface area synthesis of between 30 and 260 m 2 / g employed at a rate included between 20 and 80 phr, and preferably between 30 and 50 phr, d) either by a carbon black cutting described in (a) and / or carbon black described in (b) and / or a white charge described in (c), wherein the overall loading rate is between 20 and 80 phr, and preferably between 40 and 60 phr.
    [0010]
    10 - A tire according to one of the preceding claims, characterized in that the crown reinforcement is completed by a layer of circumferential reinforcing elements.
    [0011]
    11 - A tire according to claim 10, characterized in that the layer of circumferential reinforcing elements is radially disposed between two working crown layers.
    [0012]
    12 - A tire according to one of claims 10 or 11, characterized in that the reinforcing elements of at least one layer of circumferential reinforcing elements are metal reinforcing elements having a secant modulus at 0.7% of elongation of between 10 and 120 GPa and a maximum tangent modulus of less than 150 GPa. 15
    [0013]
    13 - A tire according to one of the preceding claims, characterized in that the crown reinforcement is completed radially on the outside by at least one additional ply, called protection ply, of reinforcing elements, oriented relative to the direction. circumferential with an angle of between 10 ° and 45 ° and in the same direction as the angle formed by the reinforcing elements of the working crown layer which is radially adjacent thereto.
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    同族专利:
    公开号 | 公开日
    EP3297849B1|2019-07-03|
    WO2016184754A1|2016-11-24|
    FR3036315B1|2017-05-12|
    EP3297849A1|2018-03-28|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2004076205A1|2003-02-17|2004-09-10|Societe De Technologie Michelin|Crown reinforcement for a radial tyre|
    WO2008046749A1|2006-10-18|2008-04-24|Societe De Technologie Michelin|Heavy goods vehicle tyre|
    WO2012017399A1|2010-08-06|2012-02-09|Pirelli Tyre S.P.A.|Tyre for wheels of heavy transport vehicles|CN107415591A|2017-05-08|2017-12-01|安徽佳通乘用子午线轮胎有限公司|A kind of Pneumatic belt tire for lifting endurance performance|FR2728510A1|1994-12-23|1996-06-28|Michelin & Cie|T / H SHAPE TIRE LESS THAN OR EQUAL TO 0.6|
    WO1997015620A1|1995-10-25|1997-05-01|The Yokohama Rubber Co., Ltd.|Rubber composition comprising carbon black having surface treated with silica|
    FR2770458B1|1997-11-05|1999-12-03|Michelin & Cie|SUMMIT FRAME FOR TIRE-HEAVY TIRE|
    FR2939722B1|2008-12-17|2010-12-31|Michelin Soc Tech|TIRE FOR HEAVY VEHICLES WITH TOP FRAME COMPRISING AT LEAST ONE LAYER OF CIRCUMFERENTIAL REINFORCING ELEMENTS|FR3059597A1|2016-12-05|2018-06-08|Compagnie Generale Des Etablissements Michelin|PNEUMATIC COMPRISING AN OVERLAPPED REINFORCEMENT FRAME|
    CA3081605A1|2017-11-17|2019-05-23|Compagnie Generale Des Etablissements Michelin|Tyre comprising a carcass reinforcement layer having improved endurance properties|
    WO2019097141A1|2017-11-17|2019-05-23|Compagnie Generale Des Etablissements Michelin|Tyre comprising a carcass reinforcement layer having improved endurance properties|
    CN112004691A|2018-04-17|2020-11-27|米其林集团总公司|Protective reinforcement comprising different layers for a pneumatic tire for a heavy civil engineering vehicle|
    法律状态:
    2016-05-20| PLFP| Fee payment|Year of fee payment: 2 |
    2016-11-25| PLSC| Search report ready|Effective date: 20161125 |
    2017-05-23| PLFP| Fee payment|Year of fee payment: 3 |
    2018-05-22| PLFP| Fee payment|Year of fee payment: 4 |
    2020-02-14| ST| Notification of lapse|Effective date: 20200108 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1554394A|FR3036315B1|2015-05-18|2015-05-18|PNEUMATIC COMPRISING WORKING LAYERS CONSISTING OF UNIT THREADS|FR1554394A| FR3036315B1|2015-05-18|2015-05-18|PNEUMATIC COMPRISING WORKING LAYERS CONSISTING OF UNIT THREADS|
    PCT/EP2016/060594| WO2016184754A1|2015-05-18|2016-05-11|Tyre comprising working layers formed by individual wires|
    EP16721450.1A| EP3297849B1|2015-05-18|2016-05-11|Tyre comprising working layers formed by individual wires|
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