Tire with low rolling resistance and manufacturing method thereof

Abstract

A tire comprising a crown reinforcement including a working reinforcement including a single working layer and a hoop reinforcement including at least one hooping filament reinforcing element (170) disposed radially outward of the working reinforcement and spirally wound circumferentially so as to extend axially from one axial end of the hoop reinforcement to the other axial end of the hoop reinforcement. The or each hooping filament reinforcing element (170) comprises two multifilament strands (1701, 1702) of aromatic polyamide or aromatic copolyamide and one multifilament strand (1703) of aliphatic polyamide or polyester, or three polyester multifilament strands, each multifilament strand (1701, 1702, 1703) spirally wound about a major axis (W) common to the three multifilament strands (1701, 1702, 1703). The hoop reinforcement has a tangent modulus at 1.3% elongation ranging from 200 to 650 daN / mm.

Description

[Technical field]

[0001] The present invention relates to a tire and a method for manufacturing such a tire. [Background technology]

[0002] The prior art, specifically WO 2019 / 122621 and WO 2019 / 180367, discloses a tire comprising a crown, two sidewall portions and two bead portions, each sidewall portion connecting a respective bead portion to the crown, each bead portion comprising at least one circumferential reinforcing element, generally in the form of a bead wire.

[0003] The tire also includes a carcass reinforcement secured to each bead portion and extending in each sidewall portion and in the crown, the carcass reinforcement including a single carcass ply including a portion wrapped around each circumferential reinforcing element.

[0004] The crown includes a tread portion that contacts the ground when the tire is rolling, and a crown reinforcement disposed radially intermediate the tread portion and the carcass reinforcement, the crown reinforcement including a single working layer.

[0005] The crown reinforcement also includes a hoop reinforcement arranged radially outward of the working reinforcement, the hoop reinforcement being axially bounded by two axial ends and including at least one hooping filamentary reinforcing element spirally wound circumferentially so as to extend axially from one axial end of the hoop reinforcement to the other axial end in the main direction of the or each hooping filamentary reinforcing element.

[0006] As mentioned above, a particular feature of the tires described in WO 2019 / 122621 and WO 2019 / 180367 is the elimination of one working layer compared to conventional tires in which the working reinforcement comprises two working layers, each working layer comprising working filament reinforcing elements axially bounded by two axial ends of said working layer and extending substantially parallel to one another from one axial end to the other axial end of said working layer in a main direction of the working filament reinforcing elements that forms an angle with the circumferential direction of the tire strictly greater than 10°, for example equal to 26°, in absolute value. The main direction of the working filament reinforcing elements of one of the working layers and the main direction of the working filament reinforcing elements of the other working layer form opposite angles with the circumferential direction of the tire, i.e. here +26° and -26°, in the parts of the tire bounded axially by the axial ends of the working reinforcing elements. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2019 / 122621 [Patent Document 2] International Publication No. 2019 / 180367 [Patent Document 3] US Patent Publication No. 20160167438 [Patent Document 4] International Publication No. 2013 / 017421 [Patent Document 5] International Publication No. 2017 / 168107 [Patent Document 6] French Patent No. 2797213 [Patent Document 7] French Patent No. 1413102 [Patent Document 8] U.S. Pat. No. 5,702,548 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the tyres described in WO 2019 / 122621 and WO 2019 / 180367 have a rolling resistance that could be improved.

[0009] The object of the present invention is to improve the rolling resistance of such tires. [Means for solving the problem]

[0010] Tire according to the invention To this end, the invention provides a tire comprising a crown, two sidewall portions and two bead portions, each sidewall portion connecting each bead portion to the crown, the tire comprising a carcass reinforcement fixed to each bead portion and extending in each sidewall portion and radially inwardly at the crown, the carcass reinforcement including a carcass layer, the crown comprising: - a tread portion intended to come into contact with the ground when the tire is rotating; a crown reinforcement disposed radially intermediate the tread portion and the carcass reinforcement, the crown reinforcement comprising: - a working reinforcement body comprising a single working layer; - a hoop reinforcement arranged radially outside the working reinforcement; wherein the hoop reinforcement is axially bounded by two axial ends of the hoop reinforcement and includes at least one hooping filament reinforcing element helically wound in the circumferential direction so as to extend axially from one axial end of the hoop reinforcement to the other axial end of the hoop reinforcement.

[0011] According to the invention, the or each hooping filament reinforcing element comprises: - two multifilament strands of an aromatic polyamide or aromatic copolyamide and one multifilament strand of an aliphatic polyamide or polyester, or - Consists of three polyester multifilament strands, Each multifilament strand is helically wound around a main axis common to the three multifilament strands.

[0012] Further according to the invention, the hoop reinforcement has a tangent modulus at 1.3% elongation in the range of 200 to 650 daN / mm.

[0013] The tire according to the invention has an improved rolling resistance, i.e., less than that of the prior art tires. For the purposes of their investigation, the inventors of the present invention have determined that the tangent modulus at 1.3% elongation is representative of the tire's behavior with respect to rolling resistance for a tire that includes a single working ply. The relevance of the tangent modulus at 1.3% elongation is demonstrated in the comparative testing section.

[0014] The tire described in WO 2019 / 122621 comprises a hoop reinforcement with a relatively low tangent modulus at 1.3% elongation, always less than 200 daN / mm. The inventors have determined that for a tire with a single working layer, if the tangent modulus at 1.3% elongation is too low, sufficient hooping function cannot be ensured, especially since the presence of only a single working layer further reduces the hooping ability of the crown reinforcement compared to conventional tires with two working layers. A relatively low tangent modulus at 1.3% elongation makes the crown reinforcement of the tire too dissipative, thus increasing the rolling resistance of the tire. In contrast, the tire according to the invention has a sufficiently high tangent modulus at 1.3% elongation, which allows sufficient hooping of the tire despite the presence of only one working layer.

[0015] The tire described in WO 2019 / 180367 includes a hoop reinforcement with a relatively high tangent modulus at 1.3% elongation, always above 650 daN / mm. The inventors have determined that in tires with a single working layer, a too high tangent modulus at 1.3% elongation prevents good flattening of the tire. In fact, a relatively high tangent modulus at 1.3% elongation makes the crown reinforcement of the tire very hard, which requires the application of relatively large forces to this crown reinforcement to ensure good flattening of the tire. Such forces generate shear forces in materials such as the elastomer matrix present near the axial ends of the hoop reinforcement in order to flatten the tire. These shears cause further dissipation, increasing the rolling resistance of the tire. In contrast, the tire according to the invention has a sufficiently high but moderate tangent modulus at 1.3% elongation, which allows good flattening of the tire despite the presence of only a single working layer.

[0016] A fundamental feature of the invention is the use of a hooping filament reinforced element constructed by helically winding together three multifilament strands on a common axis. Indeed, such a filament reinforced element requires at most two twisting steps, thus allowing a fast and cheap manufacturing process. In contrast, the hooping filament reinforced element described in WO 2019 / 122621 requires a twisting step for each core strand and layer strand and a twisting step for the core strand and layer strands together, thus making the process relatively long or requiring numerous twisting means. The hooping filament reinforced element described in WO 2019 / 180367 requires three successive twisting steps to be performed and requires numerous twisting means to do this, thus making the process long and requiring numerous twisting means.

[0017] The inventors of the present invention have also determined that, unlike tires comprising two working layers in which the hoop reinforcement exclusively serves the function of hooping the crown reinforcement of the tire, the hoop reinforcement of the tire according to the invention must perform other functions in addition to its hooping function, such as ensuring that it takes up a greater proportion of the circumferential tensions of the tire during inflation, rotation and centrifugation, and that it contributes more significantly to the guiding function of the tire through its cornering stiffness. To perform these other functions, it is necessary to have available hooping filament reinforcing elements with a force-elongation curve that can be adjusted as a function of the performance compromises desired for the tire. Each hooping filament reinforcing element consisting of three strands has a force-elongation curve that can be adjusted by modifying one or more parameters selected from at least four parameters, namely the count of each multifilament strand and the twist of these multifilament strands forming the hooping filament reinforcing element. In contrast, the force-elongation curve of a hooping filament reinforcing element consisting of two multifilament strands could not be adjusted as well, in the sense that only a smaller number of parameters can be modified.

[0018] According to the invention, the working reinforcement comprises a single working layer. The presence of a single working layer makes it possible, inter alia, to lighten the tire and therefore reduce the energy dissipated by crown hysteresis and therefore to reduce the rolling resistance of the tire. The working reinforcement therefore does not comprise any layer reinforced by filament reinforcing elements other than the working layer. The filament reinforcing elements of such reinforcing layers excluded from the working reinforcement of the tire include metal filament reinforcing elements and textile filament reinforcing elements. It is highly preferred that the working reinforcement is formed by a single working layer.

[0019] In the tire according to the invention, a hoop reinforcement is radially interposed between the working reinforcement and the tread portion.

[0020] Each multifilament strand comprises a number of monofilaments, which usually have a diameter in the range of 2 to 30 μm. Each multifilament strand of monofilaments comprises at least two elementary filaments, typically more than 10 elementary filaments, preferably more than 100 elementary filaments, more preferably more than 200 elementary filaments. Monofilament denotes a monolithic filament formed of a given material and resulting from the spinning of this material, for example by melt spinning, solution spinning or gel spinning.

[0021] The term "multifilament strand of aromatic polyamide or aromatic copolyamide" is understood to mean a multifilament strand consisting of monofilaments of linear macromolecules, at least 85% of which are formed by aromatic groups linked together by amide bonds directly attached to two aromatic rings, in particular a poly(p-phenylene terephthalamide) (or PPTA) fiber produced over a long period of time from an optically anisotropic spinning composition. Among the aromatic polyamides or aromatic copolyamides, mention may be made of polyallylamide (or PAA, known in particular under the trade name Ixef from Solvay), poly(metaxylylene adipamide), polyphthalamide (or PPA, known in particular under the trade name Amodel from Solvay), amorphous semi-aromatic polyamide (or PA 6-3T, known in particular under the trade name Trogamid from Evonik), or para-aramid (or poly(paraphenylene terephthalamide), or PA PPD-T, known in particular under the trade name Kevlar from Du Pont de Nemours, or Twaron from TEIJIN).

[0022] The term "polyester multifilament strand" is understood to mean a multifilament strand consisting of monofilaments of linear polymers formed from groups linked together by ester bonds. Polyesters are produced by polycondensation by esterification between a dicarboxylic acid or one of its derivatives and a diol. For example, polyethylene terephthalate can be produced by polycondensation of terephthalic acid and ethylene glycol. Among the known polyesters, mention may be made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polypropylene terephthalate (PPT) or polypropylene naphthalate (PPN).

[0023] The term "multifilament strand of an aliphatic polyamide" is understood to mean a multifilament strand consisting of monofilaments of linear macromolecules of polymers or copolymers that do not contain aromatic rings and contain amide functions and that can be synthesized by polycondensation between carboxylic acids and amines. Among the aliphatic polyamides, mention may be made of nylon PA4.6, PA6, PA6.6 or PA6.10, in particular Zytel from DuPont, Technyl from Solvay or Rilsamid from Arkema.

[0024] The tangent modulus of the hoop reinforcement at 1.3% elongation is calculated from the force-elongation curve obtained by applying the standard ASTM D 885 / D 885M-10a of 2014 to the hooping filament reinforcement element extracted from the tire or bonded before incorporation into the elastomeric matrix. From this force-elongation curve of the hooping filament reinforcement element, the tangent modulus of the hooping filament reinforcement element, expressed in daN / %, is deduced by calculating the derivative of the curve at the point of elongation equal to 1.3%. The tangent modulus of the hooping filament reinforcement element at 1.3% elongation, expressed in daN / mm, is obtained by multiplying this tangent modulus of the hooping filament reinforcement element by the average axial density of the hooping filament reinforcement element. The average axial density of the (single or multiple) hooping filament reinforcement element is equal to the average number of turns of the hooping filament reinforcement element per mm of the hoop reinforcement in the case of a single hooping filament reinforcement element and is equal to the average number of hooping filament reinforcement elements per mm of the hoop reinforcement in the case of a multiple hooping filament reinforcement element. The average axial density of the hooping filament reinforcing element(s) is determined in the axial direction of the tire. The determination of the axial density of the hooping filament reinforcing element(s) is performed over an axial width equivalent to 50% of the axial width of the tire axially centered on the median plane of the tire. The average axial density of the hooping filament reinforcing element(s) therefore takes into account the possibility of radial overlap of the hooping filament reinforcing elements, for example following wrapping or following the presence of two radially overlapping hooping layers in the hoop reinforcement. The average axial density of the hooping filament reinforcing element(s) does not take into account the possibility of radial overlap of the hooping filament reinforcing elements located in the axially outer parts of the tire, i.e. outside the central part having an axial width equal to 50% of the axial width of the tire axially centered on the median plane of the tire.

[0025] The tire of the invention is preferably for passenger cars, having a cross section in meridian section, characterized in that for the section width S and the section height H within the meaning of the European Tire and Rim Technical Organisation or "ETRTO", the ratio H / S, expressed as a percentage, is at most equal to 90, preferably at most equal to 80, more preferably at most equal to 70, at least equal to 30, preferably at least equal to 40, the section width S is at least equal to 115 mm, preferably at least equal to 155 mm, more preferably at least equal to 175 mm, at most equal to 385 mm, preferably at most equal to 315 mm, more preferably at most equal to 285 mm, even more preferably at most equal to 255 mm, and the diameter at the hook D, which defines the diameter of the tire mounting rim, is at least equal to 12 inches, preferably at least equal to 16 inches, at most equal to 24 inches, preferably at most equal to 20 inches.

[0026] The term axial means a direction substantially parallel to the main axis of the tire, i.e., the axis of rotation of the tire.

[0027] The term circumferential means a direction substantially perpendicular to both the axial direction and the radius of the tire (in other words, a tangent to a circle about the axis of rotation of the tire).

[0028] The term radial means any direction along the radius of the tire, i.e., intersecting the axis of rotation of the tire and substantially perpendicular to this axis.

[0029] The term median plane (designated M) of a tire means the plane perpendicular to its axis of rotation, located at the axial mid-distance between the two bead portions and passing axially midway through the crown reinforcement.

[0030] The term equatorial circumferential plane of a tire (designated E) means a theoretical cylindrical plane perpendicular to the median plane and the radial direction, passing through the equator of the tire. The equator of a tire is an axis parallel to the axis of rotation of the tire in a meridian section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions) equidistant between the radially outermost point of the tread intended to be in contact with the ground and the radially innermost point of the tire intended to be in contact with a support, for example the rim, the distance between these two points being equal to H.

[0031] The term meridian plane means a plane perpendicular to the circumferential direction of the tire, parallel to and containing the tire's axis of rotation.

[0032] The term bead portion means the portion of the tire intended to enable the tire to be hooked to a mounting support, such as a wheel including a rim, and each bead portion is therefore intended in particular to contact and hook onto a hook of the rim.

[0033] The term main direction of extension of a filament reinforcing element means the direction in which the filament reinforcing element extends along its maximum length. The main direction of extension of the filament reinforcing element can be straight or curved, and the reinforcing element can present a straight or wavy path along that main direction.

[0034] The part of an assembly, layer or tire lying between the axial ends of a wound assembly or layer or reinforcement is understood to be the part of the assembly, layer or tire which extends axially between and lies between radial planes passing through the axial ends of the wound assembly or layer or reinforcement.

[0035] A part of a winding assembly intended to extend axially, a part of a winding assembly extending axially, or a part of a layer extending axially in radial coincidence with a reference assembly or layer, is understood to be the part of said assembly or layer that is present between the radial projections of the axial ends of the reference assembly or layer on said assembly or layer.

[0036] Any numerical range expressed as "between a and b" denotes a numerical range greater than a and less than b (i.e., excluding the limits a and b), whereas any numerical range expressed as "from a to b" means a numerical range from a to b (i.e., including the precise limits a and b).

[0037] The angle considered in a tire is the smaller of the two angles, in absolute value, defined between a reference straight line, which here is the circumferential direction of the tire, and the main direction in which the filament reinforcing element considered extends.

[0038] In tires and during the method, the term orientation of an angle means the clockwise or counterclockwise direction that must be rotated from a reference straight line, here the circumferential direction of the support or tire, that defines the angle to arrive at the main direction of extension of the filament reinforcing elements considered.

[0039] During the method, the angles considered to be formed by the main directions of extension of the working filament reinforcing elements and the carcass filament reinforcing elements are conventionally opposite angles, the angle formed by the main direction of extension of each working filament reinforcing element being the smaller in absolute value of the two angles determined between a reference line, here the circumferential direction of the support or of the tire, and the main direction of extension of the working filament reinforcing element. The angle formed by the main direction of extension of each working filament reinforcing element thus determines an orientation opposite to that determined by the angle of the main direction of extension of each carcass filament reinforcing element.

[0040] In a variant in which the or each hooping filament reinforcing element consists of two multifilament strands of aromatic polyamide or aromatic copolyamide and one multifilament strand of aliphatic polyamide or polyester, - each multifilament strand of aromatic polyamide or aromatic copolyamide has a yarn count ranging from 150 tex to 350 tex; - each multifilament strand of aliphatic polyamide or polyester has a count ranging from 120 tex to 250 tex; - the assembly twist of the three multifilament strands about a common main axis is in the range of 150 turns per meter to 400 turns per meter; These properties can be considered individually or, preferably, in combination with one another.

[0041] In the variant in which the or each hooping filament reinforcing element consists of two multifilament strands of aromatic polyamide or aromatic copolyamide and one multifilament strand of aliphatic polyamide or polyester, it is advantageous that the twist factor K of the or each hooping filament reinforcing element, defined by K=R×[(T / (1000.ρ)]1 / 2, where R is the assembled twist of the three multifilament strands around a common main axis expressed in turns per meter, T is the total yarn count of the or each hooping filament reinforcing element expressed in tex and ρ is the average density of the material constituting the or each hooping filament reinforcing element, ranges from 140 to 260, preferably from 180 to 220 and even more preferably from 205 to 220. The term average density means the density of each multifilament strand weighted by its yarn count.

[0042] In a variation in which the or each hooping filament reinforcing element comprises three polyester multifilament strands, - each polyester multifilament strand has a count ranging from 300 tex to 500 tex; - the assembled twist of the three multifilament strands about a common main axis is in the range of 100 turns per meter to 250 turns per meter; These properties can be considered individually or, preferably, in combination with one another.

[0043] In the variant in which the or each hooping filament reinforcing element consists of three polyester multifilament strands, it is advantageous that the twist factor K of the or each hooping filament reinforcing element, defined by K=R×[(T / (1000.ρ)]1 / 2, where R is the winding twist of the three multifilament strands around a common main axis expressed in turns per meter, T is the total yarn count of the or each hooping filament reinforcing element expressed in tex and ρ is the density of the polyester constituting the or each hooping filament reinforcing element, is in the range from 120 to 260, preferably in the range from 130 to 200 and even more preferably in the range from 130 to 160.

[0044] The twist and count (or linear density) of each strand are determined according to standard ASTM D 885 / D 885M-10a, 2014. The count is given in tex (gram weight of 1000m of product - for reference 0.111 tex is equal to 1 denier).

[0045] Whatever variants are envisaged, it is preferred that the hooping filament reinforcing element is twist-balanced. The term twist-balanced means that every monofilament has the same twist around its own axis, regardless of the multifilament strand to which it belongs. To obtain such a twist-balanced hooping filament reinforcing element, the or each hooping filament reinforcing element is - twisting each multifilament strand in a first twist direction according to a number of turns per meter N1; - assembling the three multifilament strands by twisting them around a common main axis in a second twist direction opposite to the first twist direction according to a number of turns per meter N2; Preferably, N1=N2, such that each monofilament exhibits substantially zero twist about its own axis.

[0046] In a particularly preferred embodiment that allows to have even more means of adjusting the force-elongation curve of the or each hooping filament reinforcing element, the or each hooping filament reinforcing element consists of two multifilament strands of aromatic polyamide or aromatic copolyamide and one multifilament strand of aliphatic polyamide or polyester, each multifilament strand being wound helically on a main axis common to the three multifilament strands. In particular, on the one hand, the two different materials make it easier to adjust the mechanical properties of the or each hooping filament reinforcing element. On the other hand, since the tire according to the invention only has a single working layer, the hoop reinforcement is subjected to much higher stresses than tires comprising two hooping layers. Thus, a hooping filament reinforcing element comprising two multifilament strands of aromatic polyamide or aromatic copolyamide takes on more forces and thus allows compensation of losses of the working layer.

[0047] Thus, the ratio of the total yarn count, expressed in tex, of the aromatic polyamide or aromatic copolyamide to the total yarn count, expressed in tex, of the or each hooping filament reinforcing element is in the range from 0.60 to 0.90, and even more preferably in the range from 0.65 to 0.80.

[0048] To ensure improved hooping of the tire, the hoop reinforcement advantageously has a tangent modulus at 1.3% elongation of greater than or equal to 220 daN / mm.

[0049] To further improve the flattening of the tire, the hoop reinforcement advantageously has a tangent modulus at 1.3% elongation of less than or equal to 600 daN / mm, preferably less than or equal to 500 daN / mm.

[0050] In one embodiment, which allows achieving the expected volume of the tire and in particular accommodating the increase in volume during tire inflation, the hoop reinforcement exhibits a tangent modulus in the range of 150 to 400 daN / mm under a force equal to 2 daN / mm.

[0051] The inventors of the present invention have also determined that the tangent modulus under a force equal to 2 daN / mm represents the force exerted on the hoop reinforcement during inflation of a tire containing a single working ply. The relevance of the tangent modulus under a force equal to 2 daN / mm of elongation is demonstrated in the section on comparative tests.

[0052] The tangent modulus is calculated under a force equal to 2 daN / mm from the force-elongation curve obtained by applying the standard ASTM D 885 / D 885M-10a of 2014 to the hoop filament reinforcing elements of the hoop reinforcement. The axial density of the (single or multiple) hoop filament reinforcing elements per mm of the hoop reinforcement is also determined. This axial density is determined in the axial direction of the tire. Then, by dividing 2 daN / mm by the axial density of the (single or multiple) hoop filament reinforcing elements per mm of the hoop reinforcement, the force of the hoop filament reinforcing elements equivalent to the force of 2 daN / mm of the hoop reinforcement is obtained. By calculating the derivative of the curve at the point of this equivalent force, the tangent modulus M2'D of the hoop filament reinforcing elements, expressed in daN / %, is deduced therefrom, by multiplying the tangent modulus M2'D by the axial density of the (single or multiple) hoop filament reinforcing elements per mm of the hoop reinforcement, expressed in daN / mm.

[0053] The inventors have determined that in tires with a single working layer, a hoop reinforcement that exhibits an excessively low tangent modulus under a force equal to 2 daN / mm is unable to form a hoop reinforcement that provides a sufficient hooping function, all the more so since in a single working layer the hooping capacity of the crown reinforcement is further reduced compared to conventional tires comprising two working layers. An important consequence is that with a tangent modulus that is too low, the hoop reinforcement of a tire with a single working layer is unable to accommodate its volume when the tire is pressurized. This results in the tire achieving external dimensions that are significantly different from the expected dimensions that allow the tire to obtain the expected performance.

[0054] The inventors have also determined that in tires with a single working layer, a hooping ply exhibiting an excessively high tangent modulus under a force equal to 2 daN / mm can lead to the or each hooping filament reinforcing element being pushed radially inwards during the molding step.

[0055] To improve the hooping of a tire, it is advantageous for the hoop reinforcement to exhibit a tangent modulus of greater than or equal to 200 daN / mm under a force equal to 2 daN / mm.

[0056] To limit the risk of the or each hooping filament reinforcing element penetrating into the working reinforcement, it is advantageous for the hoop reinforcement to exhibit a tangent modulus of less than or equal to 350 daN / mm under a force equal to 2 daN / mm.

[0057] To improve the performance of the tyre, particularly with regard to cornering stiffness and high speed driving, it is advantageous for the or each hoop filament reinforcing element to extend axially in its main direction from one axial end of the hoop reinforcement to the other axial end thereof, forming an angle with the circumferential direction of the tyre of an absolute value of less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°.

[0058] Advantageously, the working layer is axially delimited by two axial ends of the working layer and comprises working filament reinforcing elements which extend axially substantially parallel to one another from one axial end to the other axial end of the working layer in a main direction of each working filament reinforcing element, the main direction of each working filament reinforcing element of the working layer forming an angle with the circumferential direction of the tire strictly greater than 10° in absolute value, preferably in the range from 15° to 50°, and even more preferably in the range from 18° to 30°.

[0059] In an advantageous embodiment which makes it possible to retain the advantages of a tire in which the carcass filament reinforcing elements extend substantially radially in each sidewall portion and the crown reinforcement has a triangular mesh, the or each carcass layer comprises carcass filament reinforcing elements delimited in the axial direction by two axial ends of the or each carcass layer and extending in the axial direction from one axial end of the or each carcass layer to the other axial end of the or each carcass layer, each carcass filament reinforcing element extending in a main direction of the or each carcass filament reinforcing element, the main direction of each carcass filament reinforcing element of the or each carcass layer being between the circumferential direction of the tire, - forming an angle, in absolute value, of strictly less than 80° in the portion of the carcass layer which extends radially in coincidence with the working layer; It is preferred that at least one portion of the radially extending carcass ply in each sidewall portion forms an angle ranging in absolute value from 80° to 90°.

[0060] In one variant of this embodiment, in which the angle of each carcass filament reinforcing element varies between the sidewall portion and the radial direction corresponding to the working layer, the carcass reinforcement comprises a single carcass layer. In this variant, the carcass reinforcement does not have any layer reinforced by filament reinforcing elements other than the single carcass layer. The filament reinforcing elements of such reinforcing layers that are excluded from the carcass reinforcement of the tire include metal filament reinforcing elements and textile filament reinforcing elements. It is highly preferred that the carcass reinforcement consists of a single carcass layer.

[0061] In another variation of this embodiment, in which the angle of each carcass filament reinforcing element differs between the sidewall portion and the radial direction corresponding to the working layer, the carcass reinforcement comprises two carcass layers, the main directions of the carcass filament reinforcing elements of the two carcass layers being substantially parallel to each other.

[0062] In the embodiment having a transition zone in which the main direction of each carcass filament reinforcing element varies substantially in angle between these portions, the or each carcass layer portion extending axially in line with the working layer and in which the main direction of each carcass filament reinforcing element forms an angle with the circumferential direction of the tire strictly less than 80° in absolute value has an axial width at least equal to 40% of the axial width of the working layer, preferably at least equal to 50%.

[0063] In embodiments having transition zones in which the main direction of each carcass filament reinforcing element varies substantially in angle between these portions, the or each carcass layer portion extending axially in line with the working layer and in which the main direction of each carcass filament reinforcing element forms an angle with the circumferential direction of the tire strictly less than 80° in absolute value has an axial width at most equal to 90% of the axial width of the working layer, preferably at most equal to 80%.

[0064] Preferably, the median plane of the tire intersects that portion of the or each carcass ply that extends axially coincident with the working ply, and more preferably, that portion of the or each carcass ply that extends axially coincident with the working ply is axially centered about the median plane of the tire.

[0065] In the embodiment having a transition zone in which the main direction of each carcass filament reinforcing element has a substantially variable angle between these portions, each portion of the or each carcass layer extending radially in each sidewall portion and in which the main direction of each carcass filament reinforcing element forms an angle with the circumferential direction of the tire of between 80° and 90° in absolute value has a radial height equal to at least 5% of the radial height of the tire, preferably at least 15% and more preferably at least 30%.

[0066] In the embodiment in which the main direction of each carcass filament reinforcing element has a transition zone in which the angle between these portions is substantially variable, each portion of the or each carcass layer extending radially in each sidewall portion and in which the main direction of each carcass filament reinforcing element forms an angle with the circumferential direction of the tire of between 80° and 90° in absolute value has a radial height at most equal to 80% of the radial height of the tire, preferably at most equal to 70% and more preferably at most equal to 60%.

[0067] Preferably, the equatorial circumferential plane of the tire intersects each of these portions of the or each carcass ply located in each sidewall portion.

[0068] In the embodiment in which the angle of each carcass filament reinforcing element varies between the sidewall portion and the radial direction coincident with the working layer, a preferential compromise of tire performance is obtained when the main direction of each carcass filament reinforcing element in the portion of the carcass layer extending axially and radially coincident with the working layer forms an angle with the circumferential direction of the tire of an absolute value of 10° or more, preferably in the range of 20° to 75°, more preferably in the range of 35° to 70°.

[0069] In the tire according to the invention, the crown comprises a tread portion and a crown reinforcement. - radially outwards by the surface intended to come into contact with the ground, and - radially inwards by the crown reinforcement, It is understood to be a strip of separated polymeric, preferably elastomeric, material.

[0070] The strip of polymeric material may be formed by a layer of polymeric, preferably elastomeric, material or by a stack of multiple layers, each layer being made of a polymeric, preferably elastomeric, material.

[0071] In an advantageous embodiment, the crown reinforcement comprises a single hoop reinforcement and a single working reinforcement. The crown reinforcement therefore does not comprise any reinforcement reinforced by filament reinforcing elements other than the hoop reinforcement and the working reinforcement. The filament reinforcing elements of such reinforcement excluded from the crown reinforcement of the tire comprise metal filament reinforcing elements and textile filament reinforcing elements. It is highly preferred that the crown reinforcement consists of a hoop reinforcement and a working reinforcement.

[0072] In a highly preferred embodiment, the crown does not have any reinforcement reinforced by filament reinforcing elements other than the crown reinforcement. The filament reinforcing elements of such reinforcement excluded from the crown of the tire include metal filament reinforcing elements and textile filament reinforcing elements. Highly preferred, the crown consists of the tread portion and the crown reinforcement.

[0073] In a highly preferred embodiment, the carcass reinforcement is placed in direct radial contact with the crown reinforcement, which in turn is placed in direct radial contact with the tread portion, with the advantage that the hoop reinforcement and the working layer are placed in direct radial contact with each other.

[0074] The expression direct radial contact means that the objects in direct radial contact with each other, in this case layers, reinforcements or tread portions, are not radially separated by any object, for example any layer, reinforcement or strip intervening radially between the objects in direct radial contact with each other.

[0075] In order to preferentially ensure an effective triangulation of the crown of the tire, the main direction of each hooping filament reinforcing element, the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form paired angles of different absolute values ​​with the circumferential direction of the tire in the portion of the tire that is axially intermediate the axial ends of the axially narrowest of the working and hoop reinforcements, also referred to as the triangular mesh formed by the hooping, working and carcass filament reinforcing elements.

[0076] In other words, for the or each hooping filament reinforcing element extending in the main hoop direction, each working filament reinforcing element extending in the main working direction, and each carcass filament reinforcing element extending in the main carcass direction, these hoop, working and carcass directions are in different pairs in the portion of the tire bounded axially by the axial ends of the axially narrowest of the working and hoop reinforcements.

[0077] In embodiments having a transition zone in which the main direction of each carcass filament reinforcing element has a substantially variable angle between these portions, the portions of the tire that are axially intermediate the axial ends of the working layer and the hoop reinforcement and in which the main direction of the or each hooping filament reinforcing element, the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form paired angles of different absolute values ​​with the circumferential direction of the tire have an axial width equal to at least 40%, preferably at least 50%, of the axial width of the working layer.

[0078] In an embodiment having a transition zone in which the main direction of each carcass filament reinforcing element has a substantially variable angle between these portions, the portions of the tire that are axially intermediate the axial ends of the working layer and the hoop reinforcement and in which the main direction of the or each hooping filament reinforcing element, the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form paired angles of different absolute values ​​with the circumferential direction of the tire have an axial width equal to at most 90%, preferably at most 80%, of the axial width of the working layer.

[0079] Preferably, the median plane of the tire intersects this portion of the tire axially intermediate the axial ends of the narrowest of the working and hoop reinforcements, and more preferably, this portion of the tire axially intermediate the axial ends of the narrowest of the working and hoop reinforcements is axially centered about the median plane of the tire.

[0080] To further improve the triangulation of the crown of the tire in embodiments where the angle of each carcass filament reinforcing element is different between the sidewall portion and the radial direction coincident with the working layer, the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form oppositely oriented angles with the circumferential direction of the tire in a portion of the tire that is axially intermediate the axial ends of the working layer.

[0081] In embodiments having transition zones in which the main direction of each carcass filament reinforcing element varies substantially in angle between these portions, the portions of the tire axially intermediate the axial ends of the working layer in which the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form opposite angles with the circumferential direction of the tire have an axial width equal to at least 40%, preferably at least 50%, of the axial width of the working layer.

[0082] In embodiments having transition zones in which the main direction of each carcass filament reinforcing element varies substantially in angle between these portions, the portions of the tire axially intermediate the axial ends of the working layer and in which the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form opposite angles with the circumferential direction of the tire have an axial width at most equal to 90%, preferably at most equal to 80%, of the axial width of the working layer.

[0083] Preferably, the median plane of the tire intersects this portion of the tire axially intermediate the axial ends of the working layer, and more preferably, this portion of the tire axially intermediate the axial ends of the working layer is axially centered about the median plane of the tire.

[0084] In one embodiment making it possible to easily fix the carcass reinforcement in each bead section, each bead section comprises at least one circumferential reinforcing element, said or at least one carcass layer comprising a portion of said or at least one carcass layer wound around the respective circumferential reinforcing element, the main direction of each carcass filament reinforcing element forming an angle of each carcass filament reinforcing element in the winding portion of said or at least one carcass layer with the circumferential direction of the tire strictly greater than 0° in absolute value, preferably in the range of 27° to 150°, more preferably in the range of 56° to 123°.

[0085] The filament reinforcing elements of each layer are advantageously embedded in an elastomeric matrix. The different layers may comprise the same elastomeric matrix or different elastomeric matrices.

[0086] An elastomeric matrix is ​​understood to mean a matrix that exhibits elastomeric behavior in the crosslinked state. Such a matrix is ​​advantageously obtained by crosslinking a composition comprising at least one elastomer and at least one other component. The composition comprising at least one elastomer and at least one other component preferably comprises an elastomer, a crosslinking system and a filler. The compositions used in these layers are conventional compositions for calendering reinforcing materials, usually based on natural rubber or other diene elastomers, reinforcing fillers such as carbon black, a curing system and conventional additives. The adhesion between the filament reinforcing elements and the matrix in which they are embedded is ensured by conventional adhesive compositions, for example RFL type adhesives or equivalent adhesives.

[0087] Each working filament reinforcing element is advantageously metallic. The term metallic filament element is understood to mean a filament element formed from one or an assembly of a plurality of elementary monofilaments entirely (100% of the thread) formed of metallic material. Such a metallic filament element is preferably implemented with one or more threads made of steel, more preferably made of pearlitic (or ferritic-pearlitic) carbon steel, hereinafter referred to as "carbon steel", or made of stainless steel (a steel that by definition contains at least 11% chromium and at least 50% iron). However, it is of course possible to use other steels or other alloys. When carbon steel is advantageously used, its carbon content (% by weight of steel) is preferably in the range of 0.05% to 1.2%, in particular in the range of 0.5% to 1.1%, these contents representing a good compromise between the mechanical properties required for the tire and the feasibility of the thread. The metal or steel used, whether specifically carbon steel or stainless steel, can itself be coated with a metal layer improving, for example, the mounting properties of the metal cord and / or the properties of its components, or the use properties of the cord and / or the tire itself, such as adhesive properties, corrosion resistance or ageing resistance. According to a preferred embodiment, the steel used is coated with a layer of brass (Zn-Cu alloy) or zinc. As mentioned above, the monofilament of each metal elementary filament comprises carbon steel and preferably has a mechanical strength ranging from 1000 MPa to 5000 MPa. Such mechanical strength corresponds to the steel types commonly encountered in the field of tires, namely NT (normal tensile), HT (high tensile), ST (super tensile), SHT (super high tensile), UT (extreme tensile), UHT (extremely high tensile) and MT (mega tensile), the use of a high mechanical strength potentially allowing an improved reinforcement of the matrix for embedding the cords and a reduction in the weight of the matrix thus reinforced. The elementary monofilament or an assembly of multiple elementary monofilaments can be coated with a polymeric material, for example as described in US Patent Publication No. 20160167438.

[0088] Method according to the invention Another object of the present invention is a method for producing a tire as described above, comprising the steps of: - forming one or more wound carcass assemblies intended to form a carcass layer by winding one or more carcass plies on a support having a substantially cylindrical shape around a main axis, - forming a wound working assembly intended to form a working layer by winding one or more working plies radially outwardly of a wound carcass assembly; the wrapped carcass assembly and the wrapped working assembly form a substantially cylindrical assembly about a major axis of the support; - deforming a substantially cylindrical assembly around a main axis of the support to obtain a substantially annular assembly around a main axis of the support, a method in which, after the deformation step, a wound hooping assembly intended to form a hoop reinforcement is radially arranged around the substantially annular assembly around the main axis of the support, the wound hooping assembly being formed by spirally winding the or each hooping filament reinforcing element or a hooping ply obtained by embedding the or each hooping filament reinforcing element in an elastomeric matrix.

[0089] The carcass assembly may be intended to form a single carcass layer, or may be intended to form two carcass layers by wrapping the carcass assembly around the sealing assembly two turns. Thus, in one embodiment where the tire includes two carcass layers, a single carcass assembly may be formed wrapped around the sealing assembly two turns, or a first radially inner carcass assembly may be formed wrapped around the sealing assembly and a second radially outer carcass assembly may be formed wrapped around the first radially inner carcass assembly, with each first and second carcass assembly forming a respective carcass layer.

[0090] In the context of the present invention, a working assembly is intended to form a single working layer.

[0091] In a simplified manner, in which only one carcass ply has to be handled to form each wound carcass assembly and in which circumferential joints between multiple carcass plies of an axial width smaller than the axial width of each wound carcass assembly to be formed are avoided, each wound carcass assembly is made up of the carcass plies intended to form each carcass layer, in other words each carcass ply is axially continuous.

[0092] When each wound carcass assembly is formed of multiple carcass plies, it is preferred to use multiple carcass plies whose main directions of the carcass filament reinforcing elements are all parallel to one another.

[0093] Likewise, in a simplified manner in which only one working ply needs to be handled to form a wound working assembly and circumferential joints between multiple working plies of smaller axial width than the axial width of the wound working assembly to be formed are avoided, the wound working assembly is made up of working plies intended to form a single working layer, in other words the working plies are axially continuous.

[0094] If the wound working assembly is formed from a number of working plies, it is preferred to use a number of working plies in which the main directions of the working filament reinforcement elements are all parallel to one another. Of course, it is also possible to consider the main directions of the working filament reinforcement elements not parallel to one another for each working ply.

[0095] In the method according to the invention, the step of forming a hooping assembly is carried out such that the or each hooping filament reinforcing element extends axially from one axial end to the other axial end of the hooping assembly in a main direction of the or each hooping filament reinforcing element, the angle which the main direction of the hooping filament reinforcing element forms with the circumferential direction of the support advantageously has an absolute value of less than or equal to 10°, preferably less than or equal to 7° and even more preferably less than or equal to 5°.

[0096] The term median plane of an assembly (denoted by m) means a plane perpendicular to the main axis of the support located at the axial mid-distance between the axial ends of the assembly.

[0097] The term equatorial circumferential plane of the assembly (denoted by e) means a theoretical cylindrical plane passing through the equator of the assembly, perpendicular to the median plane and to the radial direction. The equator of the assembly is an axis parallel to the main axis of the support in a meridian section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions) and located equidistant between the radially outermost point of the assembly and the radially innermost point of the assembly, the distance between these two points being equal to h.

[0098] The method is: - forming the green blank by radially and circumferentially expanding the green blank so as to press a radially outer surface of the green blank of the tire formed from the preformed assembly and the wound hooping assembly against a forming wall of a bridge mold; - crosslinking the green blank in a crosslinking mould to obtain a tyre; It is preferred that the compound contains

[0099] In order to prevent the or each hooping filament reinforcing element from penetrating its radially inner working reinforcement during the forming step, it is highly advantageous for the wound hooping assembly to exhibit a tangent modulus in the range of 155 to 420 daN / mm under a force equal to 2 daN / mm.

[0100] Before the embedding step, the hooping filament reinforced elements are glued. The glued filament reinforced elements are such that the fibrous material(s) constituting the filament reinforced elements are directly or indirectly (in the case of pre-glued filament reinforced elements) coated with an external layer intended to ensure adhesion between the raw or pre-glued filament reinforced elements and the matrix. Thus, conventional aqueous adhesive compositions of the RFL (elastomeric resorcinol-formaldehyde-latex(s)) type or as described in WO 2013017421 or WO 2017 / 168107 can be used.

[0101] The term prebonded refers to a filamentary reinforcing element in which the fibrous material(s) constituting the filamentary reinforcing element are directly coated with an intermediate layer of a composition intended to promote adhesion between the fibrous material(s) constituting the filamentary reinforcing element and an outer layer of a composition intended in itself to ensure adhesion between the prebonded fibrous filamentary element and the matrix in which the filamentary reinforcing element is embedded when bonded. The intermediate composition layer of a prebonded filamentary reinforcing element cannot in itself ensure the same quality of adhesion as the outer layer. An intermediate layer is advantageously used in the case of relatively non-polar fibrous materials, for example aromatic polyamides or aromatic copolyamides or certain polyesters.

[0102] In one variant, when the wound hooping assembly is formed by helical winding of the hooping filament reinforcement element, one can take into account the fact that the hooping filament reinforcement element is glued.

[0103] In another variant, one can envisage the fact that when the wound hooping assembly is formed by helical winding of the hooping filament reinforcing elements, the latter are glued and the outer composition layer intended to ensure the glue is covered with a layer of elastomeric composition.

[0104] To improve the hooping of the tire, it is advantageous if, prior to the winding step, the hooping assembly exhibits a tangent modulus of greater than or equal to 210 daN / mm under a force equal to 2 daN / mm.

[0105] To limit the risk of the or each hooping filament reinforcing element penetrating into the working reinforcement, it is advantageous for the hooping assembly prior to the winding step to exhibit a tangent modulus of less than or equal to 368 daN / mm under a force equal to 2 daN / mm.

[0106] The tangent modulus is calculated under a force equal to 2 daN / mm from a force-elongation curve obtained by applying the standard ASTM D 885 / D 885M-10a of 2014 to the hooping filament reinforced elements of the wound hooping assembly. The axial density of the (single or multiple) hooping filament reinforced elements per mm of the wound hooping assembly is also determined. This axial density is determined in the axial direction of the support. Then, by dividing 2 daN / mm by the axial density of the hooping filament reinforced elements per mm of the wound hooping assembly, the force of the hooping filament reinforced elements equivalent to the force of 2 daN / mm of the wound hooping assembly is obtained. By calculating the derivative of the curve at the point of this equivalent force, the tangent modulus M2'D of the hooping filament reinforcing element, expressed in daN / %, is deduced, and then by multiplying the tangent modulus M2'D by the axial density of the (single or multiple) hooping filament reinforcing elements per mm of the wound hooping assembly, the tangent modulus M2D of the wound hooping assembly, expressed in daN / mm, is deduced therefrom.

[0107] As with tires, the average axial density of the hooping filament reinforcing element (single or multiple) is equal to the average number of turns of the hooping filament reinforcing element per mm of the wound hooping assembly in the case of a single hooping filament reinforcing element, and the average number of hooping filament reinforcing elements per mm of the wound hooping assembly in the case of multiple hooping filament reinforcing elements. The determination of the average axial density of the hooping filament reinforcing element (single or multiple) is carried out over an axial width that corresponds to 50% of the axial width axially centered on the median plane of the support or assembly of the tire to be manufactured. The average axial density therefore takes into account the possibility of radial overlap of multiple hooping filament reinforcing elements, for example following wrapping or the presence of two radially overlapping hooping assemblies.

[0108] Prior to the molding step, a strip of polymeric material intended to form the tread portion is preferably positioned radially outward of the hooping assembly to form a green blank.

[0109] In one embodiment making it possible to preserve the properties of a radial tire provided by radial carcass filament reinforcing elements in the sidewall portion and the properties of a tire including a triangular crown reinforcement, the or each wound carcass assembly comprises carcass filament reinforcing elements which are delimited in the axial direction by two axial ends of the or each wound carcass assembly and which extend substantially parallel to one another in the axial direction from one axial end of the or each wound carcass assembly to the other axial end of the or each wound carcass assembly, each carcass filament reinforcing element extending in the or each carcass ply in a main direction of each carcass filament reinforcing element in the or each carcass ply, the main direction of each carcass filament reinforcing element forming an initial angle of each carcass filament reinforcing element with the circumferential direction of the support, the substantially cylindrical assembly being deformed to obtain a substantially toroidal assembly, - a final angle of each carcass filament reinforcing element in a portion of the or each wound carcass assembly extending axially in radial coincidence with the wound working assembly, the final angle being strictly less than 80° in absolute value; - a final angle of each carcass filament reinforcing element in the portion of the or each carcass assembly intended to extend radially in each sidewall section ranging in absolute value from 80° to 90°; It becomes possible to form.

[0110] In an embodiment in which the main direction of each carcass filament reinforcing element has a transition zone in which the angle between these portions is substantially variable, the or each carcass assembly portion extending axially in radial coincidence with the winding working assembly and in which the main direction of each carcass filament reinforcing element forms a final angle with the circumferential direction of the support body that is strictly less than 80° in absolute value has an axial width that is at least equal to 40% of the axial width of the winding working assembly, preferably at least equal to 50%.

[0111] In an embodiment in which the main direction of each carcass filament reinforcing element has a transition zone in which the angle between these portions is substantially variable, the or each carcass assembly portion extending axially in radial coincidence with the winding working assembly and in which the main direction of each carcass filament reinforcing element forms a final angle with the circumferential direction of the support body that is strictly less than 80° in absolute value has an axial width at most equal to 90%, preferably at most equal to 80%, of the axial width of the winding working assembly.

[0112] Preferably, the median plane of the assembly intersects that portion of the or each wrapped carcass assembly which extends axially in radial coincidence with the wrapping working assembly, and more preferably, that portion of the or each wrapped carcass assembly which extends axially in radial coincidence with the wrapping working assembly is axially centred on the median plane of the assembly.

[0113] The axial width of the or each wound carcass assembly portion depends, inter alia, on the deformation speed and the initial angle, and a person skilled in the art will know how to vary one and / or the other of these parameters to vary the axial width of the or each wound carcass assembly portion concerned.

[0114] In an embodiment having a transition zone in which the main direction of each carcass filament reinforcing element has a substantially variable angle between these portions, each portion of the or each wound carcass assembly intended to extend radially in each sidewall portion and in which the main direction of each carcass filament reinforcing element forms a final angle with the circumferential direction of the support in the range of 80° to 90° absolute, has a radial height at least equal to 5% of the radial height of the tire to be manufactured, preferably at least equal to 15%, more preferably at least equal to 30%.

[0115] In an embodiment in which the main direction of each carcass filament reinforcing element has a transition zone in which the angle between these portions is substantially variable, each portion of the or each wound carcass assembly intended to extend radially in each sidewall portion and in which the main direction of each carcass filament reinforcing element forms a final angle with the circumferential direction of the support in the range of 80° to 90° in absolute value has a radial height at most equal to 80%, preferably at most equal to 70%, more preferably at most equal to 60% of the radial height of the tire to be manufactured.

[0116] The equatorial circumferential plane of the assembly preferably intersects each portion of the or each wrapped carcass assembly intended to be placed in each sidewall portion.

[0117] Similarly, the radial height of the or each wrapped carcass assembly portion depends, inter alia, on the deformation speed and the initial angle, and a person skilled in the art will know how to vary the radial height of the or each wrapped carcass assembly portion involved by varying one and / or the other of these parameters.

[0118] In order to obtain a final angle at the end of the deformation step that allows a preferential compromise of the tire's performance, the initial angle that the main direction of each carcass filament reinforcing element forms with the circumferential direction of the support is strictly greater than 0° in absolute value and preferably ranges from 27° to 150°, more preferably from 56° to 123°.

[0119] Such a preferential compromise in tire performance is obtained when, in the portion of the or each wound carcass assembly extending axially in radial coincidence with the wound working assembly, the final angle that the main direction of each carcass filament reinforcing element forms with the circumferential direction of the support has an absolute value of at least 10°, preferably within the range of 20° to 75°, more preferably within the range of 35 to 70°.

[0120] In one embodiment making it possible to maintain the properties of a tire including a triangular crown reinforcement, the winding working assembly comprises working filament reinforcing elements which are axially delimited by two axial ends of the winding working assembly and which extend substantially parallel to one another in the axial direction from one axial end of the winding working assembly to the other axial end of the winding working assembly, each working filament reinforcing element extending in said or each working ply in a main direction of each working filament reinforcing element in said or each working ply, which main direction of each working filament reinforcing element in said or each working ply forms an initial angle of each working filament reinforcing element with the circumferential direction of the support, and by deformation of the substantially cylindrical assembly around the main axis of the support to obtain a substantially toroidal assembly around the main axis of the support, the main direction of each working filament reinforcing element forms a final angle of each working filament reinforcing element with the circumferential direction of the support that is strictly greater than 10° in absolute value.

[0121] In order to obtain a final angle at the end of the deformation step which allows a preferential compromise of the performance of the tire, the initial angle which the main direction of each working filament reinforcing element forms with the circumferential direction of the support is strictly greater in absolute value than 0° and preferably ranges from 4° to 60°, more preferably from 16° to 47°.

[0122] Such a preferential compromise in tire performance is obtained when the final angle that the main direction of each working filament reinforcing element forms with the circumferential direction of the support is in the range of 15° to 50°, preferably in the range of 18° to 30°, in absolute value.

[0123] In some embodiments, the final angle that the main direction of each working filament reinforcing element forms with the circumferential direction of the support is substantially equal to the angle that the main direction of each working filament reinforcing element of the working layer forms with the circumferential direction of the tire when the tire is manufactured.Similarly, in these same embodiments, the final angle that the main direction of each carcass filament reinforcing element forms with the circumferential direction of the support in the portion of the wound carcass assembly extending axially radially in line with the wound working assembly is substantially equal to the angle that the main direction of each carcass filament reinforcing element of the carcass layer(s) forms with the circumferential direction of the tire in the portion of the carcass layer(s) extending axially radially in line with the working layer after the tire is manufactured.

[0124] In other embodiments, during the step of forming the green blank in the mold, the green blank is pressed against the forming surface of the mold and undergoes a radial forming deformation that is not negligible compared to the deformation undergone during the deformation step, and a slight reduction in the final angle may occur while changing the assembly of the wound carcass assembly and the wound working assembly from a substantially cylindrical shape to a substantially toroidal shape.

[0125] In a preferred embodiment allowing an effective triangular shape to be obtained, the main direction of the or each hooping filament reinforcing element, the main direction of each working filament reinforcing element and the main direction of each carcass-like filament reinforcing element form paired angles of different absolute value with the circumferential direction of the support in the part of the wound working assembly and the wound hooping assembly which is axially present between the axial ends of the wound assembly which is the narrowest in the axial direction of the wound hooping assembly.

[0126] The parts of the wound working assembly and the wound hooping assembly which lie axially between the axial ends of the axially narrowest of the wound assemblies and in which the main direction of the or each hooping filament reinforcing element, the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form paired angles of different absolute values ​​with the circumferential direction of the support, have an axial width equal to at least 40%, preferably at least 50%, of the axial width of the wound working assembly.

[0127] The parts of the wound working assembly and the wound hooping assembly which lie axially between the axial ends of the axially narrowest of the wound assemblies and in which the main direction of the or each hooping filament reinforcing element, the main direction of each working filament reinforcing element and the main direction of each carcass filament reinforcing element form paired angles of different absolute values ​​with the circumferential direction of the support, have an axial width equal to at most 90%, preferably at most 80%, of the axial width of the wound working assembly.

[0128] Preferably, the median plane of the assembly intersects with this portion of the assembly and the wound hooping assembly that is axially intermediate between the axial ends of the one of the wound working assembly and the wound hooping assembly that is the narrowest in the axial direction.More preferably, this portion of the assembly and the wound hooping assembly that is axially intermediate between the axial ends of the one of the wound working assembly and the wound hooping assembly that is the narrowest in the axial direction is axially centered on the median plane of the assembly.

[0129] In the above-described method, the initial angle that the main direction of the carcass and working filament reinforcing elements forms with the circumferential direction of the support changes during the deformation step to reach a final angle, except for the turns of the carcass assembly wound on the circumferential reinforcing elements, where the main direction of the carcass filament reinforcing elements remains substantially the same relative to the circumferential direction of the support and therefore of the tire.

[0130] The skilled person can determine the variation of the angle of the main direction of the carcass and of the working filament reinforcing elements as a function of the speed of deformation used during the method, which is determined in a manner known to those skilled in the art as a function of the axial draw of the axial end(s) of the wound carcass assembly and the radial expansion of the assembly between the cylindrical and toroidal shapes. The determination of the initial angle as a function of the final angle depends on the speed of deformation in a manner known to those skilled in the art, as described in patents FR 2 797 213 and FR 1 413 102.

[0131] In one embodiment that allows easy fixing of the carcass reinforcement in each bead portion, after the step of forming the or at least one wound carcass assembly, - two circumferential reinforcing elements are arranged around the or at least one wound carcass assembly; - each axial end of the or at least one wound carcass assembly is bent axially inwardly so as to radially cover each circumferential reinforcing element with one of the axial ends of the or at least one wound carcass assembly to form a part of the or at least one wound carcass assembly wound around each circumferential reinforcing element; - the substantially cylindrical assembly is deformed to obtain a substantially toroidal assembly, such that a main direction of each carcass filament reinforcing element forms, in the winding portion of the or at least one wound carcass assembly, a final angle of each carcass filament reinforcing element with the circumferential direction of the support body that is strictly less than 80° in absolute value.

[0132] In the above-described embodiment, the wound portion of the or at least one wound carcass assembly is fixed around the circumferential reinforcing element so that the final angle that the main direction of each carcass filament reinforcing element in this portion forms with the circumferential direction of the support is substantially identical to the initial angle formed by the main direction of each carcass filament reinforcing element before the deformation step.

[0133] The present invention and its advantages will be readily understood in light of the following detailed description and non-limiting exemplary embodiments, and from FIGS. 1-20 in conjunction with these examples. [Brief description of the drawings]

[0134] [Figure 1] 1 is a cross-sectional view of a tire according to the present invention in a meridian section; [Diagram 2] FIG. 2 is a schematic cutaway view of the tire of FIG. 1 showing the arrangement of radially extending filament reinforcing elements in radial alignment with the working layer. [Diagram 3] FIG. 2 is a schematic diagram of a carcass filament reinforcing element disposed in a sidewall portion of the tire of FIG. 1. [Figure 4] 2 is a cross-sectional view perpendicular to the axial direction of a portion of the crown of the tire of FIG. 1. [Diagram 5]FIG. 2 is a cross-sectional view perpendicular to the main direction of extension of each hooping filament reinforcing element of the tire of FIG. 1. [Figure 6] 2 is a force-elongation curve of the hooping filament reinforcing element of the tire of FIG. 1. [Figure 7] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 8] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 9] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 10] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 11] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 12] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 13] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 14] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 15] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 16] 2A-2D are diagrams illustrating the steps of a method according to the invention making it possible to manufacture the tire of FIG. 1; [Figure 17] FIG. 13 shows the correlation coefficient R2 between the rolling resistance and the tangent modulus of the hoop reinforcement of a tire according to the invention simulated under applied forces for different models. [Figure 18] FIG. 13 shows the correlation coefficient R2 between the rolling resistance and the tangent modulus of the hoop reinforcement of a tire according to the invention simulated under imposed elongation for different models. [Figure 19]FIG. 13 shows the correlation coefficient R2 between the rolling resistance and the tangent modulus of the hoop reinforcement of a conventional tire simulated under applied force for different models. [Figure 20] FIG. 1 shows the correlation coefficient R2 between the rolling resistance and the tangent modulus of the hoop reinforcement of a conventional tire simulated under elongation for different models. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0135] The tire diagrams show reference frames X, Y, Z corresponding to the tire's normal axial (X), radial (Y) and circumferential (Z) directions, respectively. The method diagrams show reference frames x, y, z corresponding to the normal axial (x), radial (y) and circumferential (z) directions, respectively, of a manufacturing support deformable between a substantially cylindrical and a toroidal shape about an x-axis.

[0136] Figure 1 shows a tire according to the invention, designated by the reference number 10. The tire 10 rotates about an axis substantially parallel to an axial direction X. Here, the tire 10 is intended for passenger cars and has the dimensions 245 / 45R18.

[0137] The tire 10 comprises a crown 12 including a tread portion 20 intended to come into contact with the ground during rotation, and a crown reinforcement 14 extending in the circumferential direction Z at the crown 12. The tire 10 also comprises a sealing layer 15 intended to seal in an inflation gas and to define a closed internal cavity between the tire 10 and a mounting support, for example a rim, when the tire 10 is mounted on the mounting support. The sealing layer 15 comprises an elastomeric composition comprising an elastomeric matrix comprising at least 50 phr of one or more butyl elastomers.

[0138] The crown reinforcement 14 includes a working reinforcement 16 including a working layer 18 and a hoop reinforcement 17 including a single hooping layer 19. Here, the working reinforcement 16 includes a single working layer 18, which in this case consists of a single working layer 18. In the following description, for the sake of simplicity, reference will be made to the single working layer 18 without restating each time that there is one. The hoop reinforcement 17 consists of a hooping layer 19.

[0139] The crown reinforcement 14 is radially borne by a tread portion 20. In this case, a hoop reinforcement 17, here a hooping layer 19, is arranged radially outside the working reinforcement 16 and is therefore radially interposed between the working reinforcement 16 and the tread portion 20. In the embodiment shown in Figure 2, the hoop reinforcement 17 has an axial width that is smaller than the axial width of the working layer 18. The hoop reinforcement 17 is therefore the axially narrowest of the working layer 18 and the hoop reinforcement 17.

[0140] The tire 10 includes two sidewall portions 22 extending radially inward from the crown 12. The tire 10 further includes two bead portions 24 radially inward from the sidewall portions 22. Each sidewall portion 22 connects a respective bead portion 24 to the crown 12.

[0141] Each bead portion 24 comprises at least one circumferential reinforcing element 26, in this case a bead wire 28 radially bearing a mass of filling rubber 30.

[0142] The tire 10 includes a carcass reinforcement 32 secured to each bead portion 24. The carcass reinforcement 32 extends in each sidewall portion 22 and radially inwardly at the crown 12. The crown reinforcement 14 is disposed radially intermediate the tread portion 20 and the carcass reinforcement 32.

[0143] The carcass reinforcement 32 includes a carcass layer 34. Here, the carcass reinforcement 32 includes a single carcass layer 34, and in this case consists of a single carcass layer 34. In this embodiment, for the sake of simplicity, we will refer to this layer without restating the fact that there is one carcass layer 34 each time.

[0144] The carcass layer 34 includes a portion 34T of the carcass layer 34 wound around each circumferential reinforcing element 26 to form an axially inner portion 38 and an axially outer portion 40 in each bead 24. Between the axially inner portion 38 and the axially outer portion 40 is interposed a mass of filled rubber 30. Other methods of fastening the carcass layer 34 are possible, as described, for example, in US Pat. No. 5,702,548.

[0145] Each of the working layer 18, hooping layer 19 and carcass layer 34 comprises an elastomeric matrix having embedded therein one or more filament reinforcing elements of the corresponding layer. These layers will now be described with reference to Figures 1-4.

[0146] The hoop reinforcement 17, here a hoop layer 19, is axially delimited by two axial ends 17A, 17B of the hoop reinforcement 17. The hoop reinforcement 17 comprises a number of hoop filament reinforcing elements 170 spirally wound in the circumferential direction so as to extend axially from the axial end 17A of the hoop layer 17 to the other axial end 17B in the main direction D1 of each hoop filament reinforcing element 170. The main direction D1 forms an angle AF with the circumferential direction Z of the tire 10 of less than or equal to 10°, preferably less than or equal to 7°, more preferably less than or equal to 5° in absolute value, here AF=-5°. The hoop reinforcement has an average axial density of 69 threads per decimeter, i.e. 0.69 threads per mm.

[0147] The working layer 18 is axially delimited by two axial ends 18A, 18B of the working layer 18. The working layer 18 includes working filament reinforcing elements 180 that extend axially from the axial end 18A to the other axial end 18B of the working layer 18 substantially parallel to each other. Each working filament reinforcing element 180 extends in a main direction D2 of each working filament reinforcing element 180. The direction D2 forms an angle AT with the circumferential direction Z of the tire 10 strictly greater than 10° in absolute value, preferably in the range of 15° to 50°, more preferably in the range of 18° to 30°. Here, AT=24°.

[0148] The carcass layer 34 is bounded axially by two axial ends 34A, 34B of the carcass layer 34. The carcass layer 34 includes a carcass filament reinforcing element 340 that extends axially from the axial end 34A of the carcass layer 34 to the other axial end 34B.

[0149] Each carcass filament reinforcing element 340 extends in a main direction D3 of each carcass filament reinforcing element 340 and forms an angle ACS with the circumferential direction Z of the tire 10 strictly less than 80° in absolute value in a portion 34S of the carcass layer 34 extending in an axial direction radially coincident with the working layer 18. In this portion 34S of the carcass layer 34 extending in an axial direction radially coincident with the working layer 18, it is advantageous for the main direction D3 of each carcass filament reinforcing element 340 to form an angle ACS with the circumferential direction Z of the tire 10 of 10° or more in absolute value, preferably in the range from 20° to 75°, more preferably in the range from 35° to 70°. Here ACS=43°.

[0150] The portion 34S of the carcass layer 34, which extends axially in line with the working layer 18, has an axial width equal to at least 40%, preferably at least 50%, of the axial width L of the working layer 18 and at most 90%, preferably at most 80%, in this case 60% of the axial width L of the working layer 18. The median plane M of the tire 10 intersects this portion 34S. More preferably, this portion 34S is axially centered on the median plane M of the tire 10.

[0151] 1 and 3, the main direction D3 of each carcass filament reinforcing element 340 forms an angle ACF with the circumferential direction Z of the tire 10 in at least a portion 34F of the radially extending carcass layer 34 in each sidewall portion 22 ranging from 80° to 90° in absolute value, where ACF=90°.

[0152] Each portion 34F of the carcass layer 34 extending radially in each sidewall portion 22 has a radial height equal to at least 5%, preferably at least 15%, more preferably at least 30% of the radial height H of the tire 10 and at most 80%, preferably at most 70%, more preferably at most 60%, in this case equal to 41% of the radial height H of the tire 10. An equatorial circumferential plane E of the tire 10 intersects each portion 34F of the carcass layer 34 located in each sidewall portion 22.

[0153] The main direction D3 of each carcass filament reinforcing element 340 forms with the circumferential direction Z of the tire 10 in the winding portion 34T of the carcass layer 34 an angle ACT strictly greater than 0° in absolute value, preferably in the range of 27° to 150°, more preferably in the range of 56° to 123°.

[0154] As shown in Fig. 2, the main direction D1 of each hooping filament reinforcing element 170, the main direction D2 of each working filament reinforcing element 180 and the main direction D3 of each carcass filament reinforcing element 340 form pairs of angles with different absolute values ​​with the circumferential direction Z of the tire 10 in the portion PS' of the tire 10 axially present between the axial ends 17a, 17b of the hoop reinforcement 17. Also, the main direction D2 of each working filament reinforcing element 180 and the main direction D3 of each carcass filament reinforcing element 340 form opposite angles AT and ACS with the circumferential direction Z of the tire 10 in the portion PS of the tire 10 axially present between the axial ends 18A, 18B of the working layer 18. In this case, AT = -24° and ACS = +43°.

[0155] In the described embodiment, each portion PS, PS' of tire 10 has an axial width equal to at least 40%, preferably at least 50%, of the axial width L of working layer 18 and at most 90%, preferably at most 80%, in this case equal to 60% of the axial width L of working layer 18. A median plane M of tire 10 intersects each portion PS, PS' of tire 10. Further preferably, each portion PS, PS' of tire 10 is axially centered about median plane M of tire 10.

[0156] Each working filament reinforcing element 180 is an assembly of two steel monofilaments, each having a diameter equal to 0.30 mm, wound together with a pitch of 14 mm.

[0157] Conventionally, each carcass filament reinforcing element 340 comprises two multifilament strands, each comprising a monofilament yarn of polyester, here PET, which are individually over-twisted in one direction with 240 turns per meter and then twisted together in the opposite direction with 240 turns per meter. These two multifilament strands are spirally wound around each other. These multifilament strands each have a count equal to 220 tex.

[0158] 5, each hooping filament reinforcing element 170 consists of three multifilament strands 1701, 1702, 1703, in this case two multifilament strands 1701, 1702 of aromatic polyamide or aromatic copolyamide and one multifilament strand 1703 of aliphatic polyamide or polyester, here two multifilament strands 1701, 1702 of aromatic polyamide, for example Kevlar from Dupont Maydown, and one multifilament strand 1703 of aliphatic polyamide, for example Nylon T728 from Kordsa. Each multifilament strand 1701, 1702, 1703 is wound helically around a main axis W common to the three multifilament strands.

[0159] The yarn count of each multifilament strand of aromatic polyamide 1701, 1702 ranges from 150 tex to 350 tex, in this case equal to 330 tex, the yarn count of the multifilament strand of aliphatic polyamide 1703 ranges from 120 tex to 250 tex, in this case equal to 188 tex, the ratio of the total yarn count, expressed in tex, of the aromatic polyamide to the total yarn count, expressed in tex, of each hooping filament reinforcing element 170 ranges from 0.60 to 0.90, preferably ranges from 0.65 to 0.80, here equal to 0.78.

[0160] Each hooping filament reinforcement element 170 is twist-balanced and is obtained by a method comprising a first step of twisting each multifilament strand 1701, 1702, 1703 in a first twist direction according to a number of turns per meter N1. The method comprises a second step of assembling the three multifilament strands 1701, 1702, 1703 by twisting them around a common main axis W in a second twist direction opposite to the first twist direction according to a number of turns per meter N2, where N1=N2. The assembled twist N2 of the three multifilament strands 1701, 1702, 1703 around the common main axis W ranges from 150 turns per meter to 400 turns per meter, in this case N2=270 turns per meter.

[0161] With an aromatic polyamide density equal to 1.44 and an aliphatic polyamide density equal to 1.14, and with an average density of the constituent material of each hooping filament reinforcing element 170 equal to 1.37, the twist factor K of each of the above-mentioned hooping filament reinforcing elements 170 ranges from 140 to 260, preferably from 180 to 220, and more preferably from 205 to 220, here equal to 212.

[0162] The hoop reinforcement 17 also has a tangent modulus M13% at 1.3% elongation ranging from 200 to 650 daN / mm. The tangent modulus M13% is determined by multiplying the tangent modulus M13'% at 1.3% elongation of each hooping filament reinforcing element 170 shown in FIG. 6 by the average axial density of the hooping filament reinforcing elements 170 per mm of the hoop reinforcement, which is here the average number of turns of the hooping filament reinforcing element per mm of the hoop reinforcement 17. Here, M13'%=4.67 daN / %, where N=0.69 turns per mm. More precisely, the tangent modulus M13% is greater than or equal to 220 daN / mm and less than or equal to 600 daN / mm, preferably less than or equal to 500 daN / mm, here equal to 322 daN / mm.

[0163] The hoop reinforcement 14 exhibits a tangent modulus M2D in the range of 150 to 400 daN / mm under a force equal to 2 daN / mm. More precisely, the hoop reinforcement 14 exhibits a tangent modulus M2D of 200 daN / mm or more and 350 daN / mm or less under a force equal to 2 daN / mm. In the illustrated example, taking into account an average axial density of the hooping filament reinforcing elements 170 equal to 0.69 elements per mm, a force equal to 2 daN / mm represents a force equivalent to 2.9 daN / hooping filament reinforcing element, which in FIG. 6 results in an equivalent tangent modulus M2′D equal to 4.35 daN / %, i.e. a modulus M2D of 300 daN / mm of the hoop reinforcement 14.

[0164] The tire 10 is obtained by the method according to the invention which will be described with reference to Figures 7 to 13.

[0165] First, each assembly 50, 52 is manufactured by placing the filament reinforcing elements 180 and 340 of the wound working assembly 50 and wound carcass assembly 52 parallel to one another and embedding them, for example by calendering, in an uncrosslinked composition comprising at least one elastomer intended to form an elastomeric matrix when crosslinked. Plies known as straight plies are obtained in which the filament reinforcing elements are parallel to one another and to the main direction of the ply. Then, a portion of each straight ply is cut at a certain cutting angle and these portions are butted against one another to obtain plies known as angled plies in which the filament reinforcing elements of the ply are parallel to one another and form an angle with the main direction of the ply equal to the cutting angle.

[0166] In the embodiment described, on the one hand a single working ply 49 and a single carcass ply 51 are obtained, each of which has an axial width, i.e. the dimension perpendicular to the longitudinal ends of each ply, equal to the axial width of each subsequently formed wound working assembly 50 and carcass assembly 52, respectively.

[0167] 7, in a first step of assembling the green blank, a wound seal assembly 72 intended to form the sealing layer 15 is formed by winding the seal ply 70 on a support 60 having a substantially cylindrical shape around its main axis A. The support 60 has a substantially cylindrical laying surface with a radius equal to 235 mm.

[0168] 8, the carcass ply 51 is wound around the support 60 to form a wound carcass assembly 52 intended to form the carcass layer 34 radially outside the wound seal assembly 72. The wound carcass assembly 52 is axially delimited by two axial ends 52A, 52B of the carcass assembly 52 and includes carcass filament reinforcing elements 340 that extend axially substantially parallel to each other from the axial end 52A to the other axial end 52B of the wound carcass assembly 52. ​​Each carcass filament reinforcing element 340 extends in the carcass ply 51 in a main direction K3 of each carcass filament reinforcing element 340. The main direction K3 forms an initial angle A3 of each carcass filament reinforcing element 340 with the circumferential direction z of the support 60 strictly greater than 0° in absolute value, preferably ranging from 27° to 150°, more preferably ranging from 56° to 123°. Here, A3=75°.

[0169] 9 and 10, the two circumferential reinforcing elements 26 are then placed around the wound carcass assembly 52, and each of the axial ends 52A, 52B of the wound carcass assembly 52 is bent axially inward so that each of the axial ends 52A, 52B of the wound carcass assembly 52 radially wraps around each of the circumferential reinforcing elements 26 to form a portion 59 of the wound carcass assembly 52 wrapped around each of the circumferential reinforcing elements 26. The portion 59 of the wound carcass assembly 52 is intended to form the portion 34T of the carcass layer 34 wrapped around each of the circumferential reinforcing elements 26 in the tire.

[0170] 11 shows a diagram illustrating the arrangement of the carcass filament reinforcing element 340 at the end of the step of axially bending the axial ends 52A, 52B of the wound carcass assembly 52 around the circumferential reinforcing element 26. In this figure, the initial angle A3 and the portions 59 described above are shown.

[0171] Then, as can be seen with reference to FIG. 12, the working ply 49 is wound to form a wound working assembly 50 intended to form a working layer 18 radially outside the wound carcass assembly 52. ​​The wound working assembly 50 is axially delimited by two axial ends 50A, 50B of the wound working assembly 50 and includes working filament reinforcing elements 180 that extend axially substantially parallel to each other from the axial end 50A to the other axial end 50B of the wound working assembly 50. Each working filament reinforcing element 180 extends in the working ply 49 in a main direction K2 of each working filament reinforcing element 180 of the working ply 49. With reference to FIG. 13, the main direction K2 forms an initial angle A2 of each working filament reinforcing element 180 with the circumferential direction z of the support 60 strictly greater than 0° in absolute value, preferably ranging from 4° to 60°, more preferably ranging from 16° to 47°. Here, A2=35°.

[0172] The wound carcass assembly 52 and the wound working assembly 50 then form a substantially cylindrical assembly 58 about the major axis A of the support 60 .

[0173] Figure 13 shows a view similar to Figure 11 illustrating the arrangement of the carcass filament reinforcing element 340 and the working filament reinforcing element 180 at the end of the step of forming the wound working assembly 50. In this figure, the initial angles A2 and A3 are shown.

[0174] The main direction K2 of each working filament reinforcing element 180 and the main direction K3 of each carcass filament reinforcing element 340 form opposite initial angles A2 and A3 with the circumferential direction z of the support 60 in the portion AC of the assembly 58 present between the axial ends 50A, 50B of the wound working assembly 50, where the axial width of the portion AC is substantially equal to the axial width of the wound working assembly 50. In this case A2=-35° and A3=+75°.

[0175] The substantially cylindrical assembly 58 around the main axis A of the support 60 is then deformed so as to obtain a substantially toroidal assembly 58 around the main axis A of the support 60. The deformed assembly 58 shown in Figure 14 is obtained. The laying surface of the support 60 then has a radius equal to 327 mm at the level of the median plane of the support.

[0176] With reference to FIG. 15, the substantially cylindrical assembly 58 around the main axis A of the support 60 is deformed to obtain a substantially annular assembly 58 around the main axis A of the support 60, so that the main direction K3 of each carcass filament reinforcing element 340 forms a final angle B3S of each carcass filament reinforcing element 340 with the circumferential direction z of the support 60 in the part 52S of the wound carcass assembly 52 extending axially in radial coincidence with the winding working assembly 50, the absolute value of which is strictly less than 80°. The final angle B3S is advantageously greater than or equal to 10°, preferably ranging from 20° to 75°, more preferably ranging from 35° to 70°. Here, B3S=43°. The part 52S of the wound carcass assembly 52 is intended to form the part 34S of the carcass layer 34.

[0177] The portion 52S of the winding carcass assembly 52, extending axially in radial coincidence with the winding working assembly 50, has an axial width equal to at least 40%, preferably at least 50%, of the axial width l of the winding working assembly 50 and equal to at most 90%, preferably at most 80%, in this case equal to 60% of the axial width l of the winding working assembly 50. The median plane m of the assembly 58 intersects this portion 52S. It is even more preferred that this portion 52S is axially centered on the median plane m of the assembly 58.

[0178] The substantially cylindrical assembly 58 around the main axis A of the support 60 is deformed to obtain a substantially annular assembly 58 around the main axis A of the support 60 such that the main direction K3 of each carcass filament reinforcing element 340 forms a final angle B3F of each carcass filament reinforcing element 340 ranging from 80° to 90° in absolute value with the circumferential direction z of the support 60 in the portion 52F of the wound carcass assembly 52 intended to extend radially in each sidewall portion 22 of the tire 10. Each portion 52F of the wound carcass assembly 52 is intended to form each portion 34F of the carcass layer 34.

[0179] Each portion 52F of the wound carcass assembly 52 intended to extend radially in each sidewall portion 22 has a radial height equal to at least 5%, preferably at least 15%, more preferably at least 30% of the radial height H of the manufactured tire and at most 80%, preferably at most 70%, more preferably at most 60%, in this case equal to 41% of the radial height H of the manufactured tire. The equatorial circumferential plane e of the assembly 58 intersects each portion 52F of the wound carcass assembly 52 intended to be placed in each sidewall portion 22.

[0180] The final angle B3T that the main direction K3 of each carcass filament reinforcing element 340 in the wound portion 59 of the wound carcass assembly 52 forms with the circumferential direction z of the support 60 during the deformation step is substantially identical to the initial angle A3 before the deformation step.

[0181] The substantially cylindrical assembly 58 around the main axis A of the support 60 is deformed to obtain a substantially annular assembly 58 around the main axis A of the support 60, such that the main direction K2 of each working filament reinforcement element 340 forms with the circumferential direction z of the support 60 a final angle B2 of each working filament reinforcement element 340 strictly greater than 10° in absolute value. Advantageously, the final angle B2 ranges from 15° to 50°, preferably from 18° to 30° in absolute value, here B2=24°.

[0182] The main direction K2 of each working filament reinforcing element 180 and the main direction K3 of each carcass filament reinforcing element 340 form opposite final angles B2 and B3S with the circumferential direction z of the support 60 in the portion AC of the assembly 58 that is axially present between the axial ends 50A, 50B of the wound working assembly 50. In this case B2=-24° and B3S=+43°.

[0183] During this process, a plurality of hooping filament reinforcing elements 170 , preferably bonded together, are embedded in an elastomeric matrix to form the hooping ply 74 .

[0184] Next, as shown in Figure 16, a wrapped hooping assembly 76 intended to form the hoop reinforcement 17 is placed radially around the assembly 58 already formed on the support 60. Here, the wrapped hooping assembly 76 is formed by spirally winding the hooping ply 74 on a toroidal shape, and then the wrapped hooping assembly 76 is transferred using a transfer ring radially outside the already formed assembly 58. Alternatively, the hooping ply 74 can be spirally wound circumferentially directly around the already formed assembly 58 to form the wrapped hooping assembly 76.

[0185] The wound hooping assembly 76 exhibits a tangent modulus M2D in the range of 155 to 420 daN / mm under a force equal to 2 daN / mm. More precisely, the hooping assembly 76 exhibits a tangent modulus M2Dc of 210 daN / mm or more and 368 daN / mm or less under a force equal to 2 daN / mm. In the illustrated example, the average axial density of the hooping filament reinforcement elements 170 in the wound hooping assembly 76 is slightly less than the average axial density of the hoop reinforcement 17, in this case equal to 0.66 elements per mm, and a force equal to 2 daN / mm represents an equivalent force of 3.03 daN / hooping filament reinforcement element, which corresponds to an equivalent tangent modulus M2'Dc equal to 4.57 daN / %, i.e. a modulus M2Dc equal to 301 daN / mm of the wound hooping assembly 76.

[0186] In the illustrated embodiment, the wrapped hooping assembly 76 has an axial width that is smaller than the axial width of the wrapped working assembly 50. Thus, the wrapped hooping assembly 76 is the axially narrowest of the wrapped working assembly 50 and the wrapped hooping assembly 76.

[0187] The angle A1 that the main direction K1 of each hooping filament reinforcing element 170 forms with the circumferential direction z of the support 60 has an absolute value of less than or equal to 10°, preferably less than or equal to 7°, more preferably less than or equal to 5°, here equal to 5°.

[0188] The main direction K1 of each hooping filament reinforcing element 170, the main direction K2 of each working filament reinforcing element 180 and the main direction D3 of each carcass filament reinforcing element 340 form paired angles with different absolute values ​​with the circumferential direction z of the support 60 at a portion AC' that is axially midway between the axial ends 76A, 76B of the assembly 58 and the wound hooping assembly 76.

[0189] The assembly 58 and the portion AC' of the wound hooping assembly 76, present axially intermediate the axial ends 76A, 76B, have an axial width equal to at least 40%, preferably at least 50% and at most 90%, preferably at most 80%, of the axial width L of the wound working assembly 50, in this case equal to 60% of the axial width L of the wound working assembly 50. The median plane m of the assembly 58 intersects this portion AC'. It is even more preferred that this portion AC' is axially centered on the median plane m of the assembly 58.

[0190] A strip of polymeric material intended to form the tread portion 20 is then placed radially outward of the wrapped hooping assembly 76 to form a green blank of the tire 10. In one variation, after the strip of polymeric material intended to form the tread portion 20 is placed radially outward of the hooping assembly 76, the assembly can be moved radially outward of the assembly 58 already formed on the support 60. In another variation, the wrapped hooping assembly 76 can be placed radially around the assembly 58 already formed on the support 60, after which the strip of polymeric material intended to form the tread portion 20 is placed.

[0191] The green blank of tire 10 formed from the already formed assembly 58 and wound hooping assembly 76 is then molded by expanding the green blank radially and circumferentially so as to press the radially outer surface of the green blank against the molding walls of the bridge mold.

[0192] The green blank is then crosslinked in a crosslinking mould, for example by vulcanisation, so as to obtain the tyre 10 .

[0193] Comparative Test In the present invention, the optimal descriptor for evaluating the rolling resistance of a tire with a single working layer was first determined. For this purpose, various correlation functions conventionally used by those skilled in the art, such as linear, quadratic or cubic functions (function 1, function 2, function 3, function 4), were used to show the correlation between the tangent modulus of a hoop reinforcement simulated on a tire with a single working layer similar to tire 10 described above and various hooping filament reinforcing elements and the rolling resistance. Thus, rolling resistance simulations were performed for hooping filament reinforcing elements with different tangent modulus values. Then, a scan was performed for various forces for which this tangent modulus could be calculated. Then, an attempt was made to transfer each correlation function to a simulated cloud of rolling resistance points, and the correlation coefficient R2 was recorded for each correlation function at each level of force. The results of these simulations are shown in FIG. 17. A similar approach was performed by scanning various elongations for which the tangent modulus could be calculated. The results of these simulations are shown in FIG. 18. From these FIG. 17 and FIG. 18, it is confirmed that the tangent modulus M13% at elongation equal to 1.3%, correlated using correlation function 1, is the optimal descriptor.

[0194] The same approach was reproduced for a conventional tire of the prior art, comprising a carcass layer with carcass filament reinforcing elements extending in a main direction forming a substantially constant angle equal to 90° with the circumferential direction of the tire, and two working layers with working filament reinforcing elements. The main direction of extension of each working filament reinforcing element of the radially innermost working layer and the main direction of extension of each working filament reinforcing element of the radially outermost working layer form opposite angles with the circumferential direction of the tire, the absolute value of which is equal to 26°. The results of these simulations are shown in Figures 19 and 20. It is confirmed that the tangent modulus M1% at elongation equal to 1%, correlated using the correlation function 1, is the best descriptor.

[0195] Table 1 below summarizes the tangent modulus M13% at 1.3% for nine hooping filament reinforcement elements and the corresponding rolling resistance RR13 for a tire including a single working layer similar to the simulated working layer. Table 1 below further summarizes the tangent modulus M1% at 1% elongation simulated for a hooping assembly including the same nine hooping filament reinforcement elements and the corresponding rolling resistance R1 for a tire including two working layers similar to the simulated working layer.

[0196] Element 1 is the hooping filament reinforcing element 170 described above.

[0197] Element 2 consists of two multifilament strands of aromatic polyamide of 250 tex each, and one multifilament strand of aliphatic polyamide of 140 tex, wound individually and then helically wound together with a twist equal to 300 turns per meter.

[0198] Element 3 consists of two aromatic polyamide multifilaments of 250 tex each and one aliphatic polyamide multifilament of 210 tex wound individually and then helically wound together with a twist equal to 300 turns per meter.

[0199] Element 4 consists of two multifilament strands of aromatic polyamide, each of 250 tex, and one multifilament strand of polyethylene terephthalate, of 220 tex, wound individually and then helically wound together with a twist equal to 300 turns per meter.

[0200] Element 5 consists of two multifilament strands of aromatic polyamide, each of 167 tex, and one multifilament strand of aliphatic polyamide, of 140 tex, wound individually and then helically wound together with a twist equal to 360 turns per meter.

[0201] Element 6 consists of three multifilament strands of polyethylene terephthalate, each of 440 tex, wound individually and then helically wound together with a twist equal to 160 turns per meter.

[0202] Elements 7 and 8 have a "core-insertion" type structure as described in WO 2019 / 122621. Element 7 comprises an aliphatic polyamide core strand of 47 tex wound individually at 340 turns per meter and three aromatic polyamide layer strands of 167 tex wound individually at 315 turns per meter, wound together at 315 turns per meter. Element 8 comprises an aliphatic polyamide core strand of 47 tex wound individually at 300 turns per meter and three aromatic polyamide layer strands of 167 tex wound individually at 270 turns per meter, wound together at 270 turns per meter.

[0203] Element 9 has a triple twist structure A110 / 1 / 2 / 3 as described in WO 2019 / 180367. TIFF0007657788000001.tif62155 Table 1

[0204] In a conventional tire comprising two working layers, the elements 1 to 6 do not allow obtaining a significantly improved rolling resistance with respect to the elements 7 to 9, and in particular with respect to the elements 7 and 8 (significantly improved here means at least 0.05 kg / t lower). In contrast, and unexpectedly, in a tire comprising a single working layer, these elements 1 to 6 allow obtaining a significantly improved rolling resistance with respect to the elements 7 to 9 (at least 0.05 kg / t lower). Thus, there is no doubt that the elements 1 to 6 allow improving the rolling resistance of the tire according to the invention, even if the tangent modulus at 1% elongation is significantly different with respect to the elements 7 to 9.

[0205] The same procedure was also reproduced to determine the capacity of a tire to reach and accommodate a predicted volume under a given inflation pressure. For this purpose, as in the case of rolling resistance, various correlation functions (Function 1, Function 2, Function 3, Function 4) were used to show the correlation between the tangent modulus and the radial elongation CF of the hoop reinforcement of tires with a single working layer similar to tire 10 and various hooping filament reinforcing elements under a pressure of 2.5 bar. The same was done for tires with two working layers. As a result of this investigation, - the best descriptor to simulate the capacity of a tire with a single working layer to reach and accommodate the expected volume under a given inflation pressure is the tangent modulus M2D at a force of 2 daN / mm; - the best descriptor to simulate the capacity of a tire with two working layers to reach and accommodate the expected volume under a given inflation pressure is the tangent modulus M1D at a force of 1 daN / mm; I found out that...

[0206] Simulation results of tires including hooping filament reinforcing elements 1 to 9 are summarized in Table 2. TIFF0007657788000002.tif62154 Table 2

[0207] In conventional tires with two working layers, elements 1 to 6 presented a risk of not reaching the expected volume, especially for element 8. In contrast and unexpectedly, these elements 1 to 6 make it possible to reach the expected volume without the risk of not containing it, unlike element 9, which does not make it possible to obtain the expected volume in tires with a single working layer. Thus, there is no doubt that elements 1 to 6 make it possible to reach and contain the expected volume of the tire under a given inflation pressure, even if the tangent modulus at 1% elongation is significantly different for elements 7 to 9.

[0208] The present invention is not limited to the above-described embodiments.

[0209] In particular, the invention may also be practiced by using two carcass layers instead of a single carcass layer.

[0210] It is also possible to envisage a variant of the above-mentioned element 6, in which the or each hooping filament reinforcing element consists of three polyester multifilament strands, in which the yarn count of each polyester multifilament strand is preferably in the range from 300 tex to 500 tex, for example equal to 440 tex, and the assembled twist of the three polyester multifilament strands around a common main axis is preferably in the range from 100 turns per meter to 250 turns per meter, for example equal to 160 turns per meter. The twist factor K of the or each hooping filament reinforcing element of this variant is in the range from 120 to 260, preferably in the range from 130 to 200, even more preferably in the range from 130 to 160, for example equal to 156.

Claims

1. A tire (10) comprising a crown (12), two sidewall portions (22) and two bead portions (24), each sidewall portion (22) connecting a respective bead portion (24) to said crown (12), said tire (10) comprising a carcass reinforcement (32) fixed to each bead portion (24) and extending in each sidewall portion (22) and extending radially inwardly in said crown (12), said carcass reinforcement (32) including a carcass layer (34), said crown (12) comprising: a tread portion (20) intended to come into contact with the ground when said tire (10) is rotating; a crown reinforcement (14) arranged radially intermediate said tread portion (20) and said carcass reinforcement (32), The crown reinforcement body (14) is a working reinforcement (16) comprising a single working layer (18); - a hoop reinforcement (17) arranged radially outside said working reinforcement (16), The hoop reinforcement (17) is The hoop reinforcement (17) is axially separated by two axial ends (17A, 17B) of the hoop reinforcement (17) and has at least one hooping filament reinforcing element (170) spirally wound in the circumferential direction so as to extend axially from one axial end (17A, 17B) of the hoop reinforcement (17) to the other axial end (17A, 17B), The or each of said hooping filament reinforcing elements (170) - two multifilament strands (1701, 1702) of an aromatic polyamide or aromatic copolyamide and one multifilament strand (1703) of an aliphatic polyamide or polyester, or - 3 polyester multifilament strands, It consists of Each multifilament strand (1701, 1702, 1703) is wound helically around a main axis (W) common to the three multifilament strands (1701, 1702, 1703); The hoop reinforcement (17) has a tangent modulus at 1.3% elongation (M13%) in the range of 200 to 650 daN / mm. A tire (10).

2. One or each of the hooping filament reinforcing elements (170) consists of two multifilament strands (1701, 1702) of aromatic polyamide or aromatic copolyamide and one multifilament strand (1703) of aliphatic polyamide or polyester, each multifilament strand (1701, 1702, 1703) being wound helically around a main axis (W) common to the three multifilament strands (1701, 1702, 1703), A tire (10) according to claim 1.

3. The hoop reinforcement (17) has a tangent modulus (M13%) at 1.3% elongation of 220 daN / mm or more. A tire (10) according to claim 1 or 2.

4. The hoop reinforcement (17) has a tangent modulus (M13%) at 1.3% elongation of 600 daN / mm or less. A tire (10) according to any one of claims 1 to 3.

5. said hoop reinforcement (17) exhibiting a tangent modulus (M2D) in the range of 150 to 400 daN / mm under a force equal to 2 daN / mm; A tire (10) according to any one of claims 1 to 4.

6. The hoop reinforcement (17) exhibits a tangent modulus (M2D) under a force equal to 2 daN / mm of 200 daN / mm or more and 300 daN / mm or less. A tire (10) according to any one of claims 1 to 5.

7. the working layer (18) comprises working filament reinforcing elements (180) that are axially delimited by two axial ends (18A, 18B) of the working layer (18) and extend axially substantially parallel to one another from one axial end (18A, 18B) of the working layer (18) to the other axial end (18A, 18B) in a main direction (D2) of each working filament reinforcing element (180), the main direction (D2) of each working filament reinforcing element (180) of the working layer (18) forming an angle (AT) with the circumferential direction (Z) of the tire (10) that is strictly greater than 10° in absolute value, A tire (10) according to any one of claims 1 to 6.

8. One or each of the carcass layers (34) is axially separated by two axial ends (34A, 34B) of the or each carcass layer (34) and includes a carcass filament reinforcing element (340) extending axially from one axial end (34A, 34B) of the or each carcass layer (34) to the other axial end (34A, 34B), each carcass filament reinforcing element (340) extending in a main direction (D3) of the respective carcass filament reinforcing element (340), the main direction (D3) of each of the carcass filament reinforcing elements (340) of the or each carcass layer (34) being spaced apart from the circumferential direction (Z) of the tire (10), - forming an angle (ACS) strictly less than 80° in absolute value in a portion (34S) of said carcass layer (34) extending axially in radial coincidence with said working layer (18); - forming an angle (ACF) ranging in absolute value from 80° to 90° in at least a portion (34F) of said carcass layer (34) extending radially in each sidewall portion (22); A tire (10) according to any one of claims 1 to 7.

9. the main direction (D3) of each carcass filament reinforcing element (340) forms an angle (ACS) with an absolute value of 10° or more with the circumferential direction (Z) of the tire (10) in the portion (34S) of the carcass layer (34) extending axially in coincidence with the radial direction of the working layer (18); A tire (10) according to claim 8.

10. A method for manufacturing a tire (10) according to any one of claims 1 to 9, comprising the steps of: - forming one or more wound carcass assemblies (52) intended to form a carcass layer (34) by winding one or more carcass plies (51) on a support (60) having a substantially cylindrical shape around a main axis (A); - forming a wound working assembly (50) intended to form a working layer (18) by winding a working ply (49) or a number of working plies (50) radially outside said wound carcass assembly (52); the wound carcass assembly (52) and the wound working assembly (50) form a substantially cylindrical assembly (58) around the main axis (A) of the support (60); - deforming said substantially cylindrical assembly (58) around said main axis (A) of said support (60) so as to obtain a substantially annular assembly (58) around said main axis (A) of said support (60); radially arranging, after said deformation step, around said substantially annular assembly (58) around said main axis (A) of said support (60), a wound hooping assembly (76) intended to form a hoop reinforcement (17), said wound hooping assembly (76) being formed by helically winding one or each of said hooping filament reinforcing elements, or a hooping ply (74) obtained by embedding one or each of said hooping filament reinforcing elements (170) in an elastomeric matrix, A method comprising:

Images