Pneumatics featuring an optimized shrink-fit reinforcement arrangement

Abstract

The present invention relates to a tire (1) comprising a crown (7) including a shrink-fit reinforcement (17) formed by winding a strip over several circumferential turns. The winding of the strip forms first (45) and second (46) shrink-fit arrangements comprising a singular axial zone (Z1). The singular axial zone (Z1) is arranged axially above a rib (19C) of the tread (33) of the tire (1). Figure for the abstract: Fig 1

Description

Title of the invention: Pneumatics featuring an optimized shrink-fit armature arrangement

[0001] The technological field of the invention is that of the tire, in particular for passenger vehicles and vans.

[0002] The invention relates to a tire comprising a crown, two sidewalls, and two bead ribs, each sidewall connecting each bead to the crown. The crown of the tire comprises a tread and also a crown reinforcement arranged radially internally to the tread and a carcass reinforcement arranged radially internally to the crown reinforcement in the crown and anchored in each bead.

[0003] The top reinforcement comprises a working reinforcement and a shrink-fit reinforcement. The working reinforcement is arranged radially internally to the shrink-fit reinforcement. The working reinforcement comprises at least one working layer. The shrink-fit reinforcement comprises a strip wound in several circumferential turns and extends axially within the top reinforcement.

[0004] Document KR101148609B1 discloses a shrink-fitting frame in which the strip is wound in several circumferential turns so as to form first and second shrink-fitting arrangements radially superimposed on one another, the second shrink-fitting arrangement being arranged radially externally to the first shrink-fitting arrangement. The strip includes a circumferential starting edge and a circumferential ending edge.

[0005] The shrink-fitting reinforcement of KR101148609B1 comprises a first portion of the first shrink-fitting arrangement extending axially from the circumferential starting edge to a first strip reversal zone. The shrink-fitting reinforcement also comprises a first portion of the second shrink-fitting arrangement, in contact with the first portion of the first shrink-fitting arrangement, extending axially from the first reversal zone to a strip release zone. The shrink-fitting reinforcement then comprises a second portion of the first shrink-fitting arrangement, extending axially from the first portion of the second shrink-fitting arrangement from the release zone to a second strip reversal zone.The shrink-fitting armature finally comprises a second portion of the second shrink-fitting arrangement, in contact with the second portion of the first shrink-fitting arrangement, extending axially from the second turning zone to the circumferential arrival edge.

[0006] It was noted that the tire disclosed in KR101148609B1, despite the presence of two shrink-fit arrangements, showed traces of penetration of corrosive agents into the top reinforcement via the shrink-fit reinforcement.

[0007] Thus, the invention aims to define an arrangement of the apex allowing to limit the entry of corrosive agents.

[0008] The invention relates first to a tire comprising a crown, two sidewalls, two beads, each sidewall connecting each bead to the crown, the crown comprising a tread including at least one rib, the crown comprising a crown reinforcement including a shrink-fit reinforcement arranged radially inside the tread, the shrink-fit reinforcement comprising a strip wound in several circumferential turns so as to form first and second shrink-fit arrangements and comprising a circumferential starting edge and a circumferential finishing edge, the second shrink-fit arrangement being arranged radially externally to the first shrink-fit arrangement, a first portion of the first shrink-fit arrangement, in contact with a bearing surface, extending axially from the circumferential starting edge to a first zone of the strip turning over,a first portion of the second shrink-fit arrangement, in contact with the first portion of the first shrink-fit arrangement, extending axially from the first turning zone to a strip release zone, a second portion of the first shrink-fit arrangement, in contact with the bearing surface, extending axially from the first portion of the second shrink-fit arrangement from the release zone to a second strip turning zone, a second portion of the second shrink-fit arrangement, in contact with the second portion of the first shrink-fit arrangement, extending axially from the second turning zone to the circumferential end edge, the shrink-fit reinforcement includes a singular axial zone comprising the circumferential start and / or end edge and comprising: , - a portion of the first shrink-fit arrangement in which the first shrink-fit arrangement is not radially covered by the second shrink-fit arrangement, and / or - a portion of a third shrink-fit arrangement in which the third shrink-fit arrangement radially covers the second shrink-fit arrangement, the singular axial zone ZI being partly arranged axially in line with at least one rib.

[0009] The invention also relates to a second object: a tire comprising a crown, two sidewalls, two ribs, each sidewall connecting each rib to the crown, the crown comprising a tread including at least one rib, the apex comprising an apex reinforcement comprising a shrink-fit reinforcement arranged radially inside the tread, the shrink-fit reinforcement comprising a strip A and a strip B wound in several circumferential turns so as to form first and second shrink-fit arrangements, each strip A and strip B comprising a circumferential starting edge and circumferential finishing edge, the second shrink-fit arrangement being arranged radially externally to the first shrink-fit arrangement, a first portion of the first shrink-fit arrangement, in contact with a bearing surface, comprising several circumferential turns of strip A and extending axially from the circumferential starting edge of strip A to a turning zone of strip A, a first portion of the second shrink-fit arrangement, in contact with the first portion of the first shrink-fit arrangement,comprising several circumferential turns of strip A and extending axially from the turning zone of strip A to the circumferential arrival edge of strip A, a second portion of the first shrink-fit arrangement, in contact with the bearing surface, comprising several circumferential turns of strip B and extending axially from the circumferential starting edge of strip B to a turning zone of strip B, a second portion of the second shrink-fit arrangement, in contact with the second portion of the first shrink-fit arrangement, comprising several circumferential turns of strip B and extending axially from the turning zone of strip B to the circumferential arrival edge of strip B, a singular axial zone,including at least one of the circumferential starting and / or ending edges of strip A or strip B and including: , - a portion of the first shrink-fit arrangement in which the first shrink-fit arrangement is not radially covered by the second shrink-fit arrangement and / or - a portion of a third shrink-fit arrangement in which the third shrink-fit arrangement radially covers the second shrink-fit arrangement, the singular axial zone ZI being partly arranged axially in line with at least one rib.

[0010] The arrangement of the singular axial zone axially aligned with the rib ensures protection of the apex reinforcement thanks to the thickness of the rib material. To this end, the singular axial zone may have an axial portion aligned with the rib and a complementary portion that is not aligned with the rib. In order to maximize the protective effect of the apex reinforcement, the inventors recommend maximizing the axial portion of the singular axial zone that is aligned with the rib.

[0011] The thickness of the rib material thus prevents the entry of corrosive agents into the top reinforcement but also offers increased resistance to perforations.

[0012] The term "in line with a rib" means the axial part between the two radial projections of the two lateral faces of the rib.

[0013] In a first variant of the first and second objects of the invention, the singular axial zone comprises the portion of the first shrink-fit arrangement which is not radially covered by the second shrink-fit arrangement and which forms a portion in underthickness.

[0014] In a second variant of the first and second objects of the invention, the singular axial zone comprises the portion of the third shrink-fit arrangement in which the third shrink-fit arrangement radially covers the second shrink-fit arrangement and which forms an overthick portion.

[0015] In a third variant of the first and second objects of the invention, the singular axial zone comprises a portion with less thickness and a portion with more thickness as described above.

[0016] Thus, whatever the object and variant, the singular axial zone has at least one portion with a thickness strictly less than the thickness of the assembly of the first and second arrangements and / or a portion with a thickness strictly greater than the thickness of the assembly of the first and second arrangements.

[0017] In the first variant of each first and second object of the invention, the thickness of the rib compensates for the void created by the portion under thickness in order to maintain a sufficient level of protection of the top reinforcement.

[0018] In the second embodiment of each of the first and second objects of the invention, the thickness of the rib allows the thicker portion to be sufficiently distanced from the surface of the tread that is in contact with the ambient air. Thus, the thickness of the tread prevents perforation and the propagation of potential corrosive agents into the thicker portion.

[0019] The first shrink-fit arrangement has radially internal and external boundaries formed respectively by a radially internal and external surface of the first arrangement. The second shrink-fit arrangement has radially internal and external boundaries formed respectively by a radially internal and external surface of the second arrangement. The thickness of the assembly of the first and second arrangements is the radial distance between the radially internal surface of the first arrangement and the radially external surface of the second arrangement. In the case of a variable thickness, the thickness considered is an average thickness.

[0020] Each first and second object of the invention comprises at least two first and second shrink-fit arrangements forming at least a portion of the shrink-fit reinforcement. Each first and second shrink-fit arrangement is formed from at least one strip wound in several circumferential turns. The first arrangement extends from the circumferential starting edge of the strip in question and externally into contact with a bearing surface of the first arrangement. Preferably, the bearing surface of the first arrangement is formed at least in part by the radially external surface of the working reinforcement. The second arrangement extends to a circumferential ending edge of the strip in question and externally into contact with a bearing surface. Preferably, the bearing surface of the second arrangement is formed at least in part by a radially external surface of the first arrangement.The second shrink-fit arrangement is thus arranged radially externally to the first arrangement and radially internally to the tread.

[0021] The starting circumferential edge of the strip(s) corresponds to a first end of the strip in question, and the ending circumferential edge corresponds to the second end of the strip in question, the strip being continuous between the first and second ends. Generally, a strip comprises two longitudinal edges extending along the longitudinal direction of the strip and two starting and ending circumferential edges extending along the transverse direction of the strip.

[0022] Each detachment zone is a zone in which the strip changes its bearing surface without changing its axial winding direction, the strip passing from the bearing surface formed by, preferably, the radially external surface of the first arrangement to the bearing surface of the first arrangement, which preferably is the radially external surface of the working reinforcement.

[0023] Each turning zone is a zone in which the strip changes its bearing surface while changing its axial direction of winding, the strip passing from the bearing surface formed by the bearing surface of the first arrangement, which preferably is the radially outer surface of the working frame to the bearing surface of the second arrangement formed, preferably, by the radially outer surface of the first arrangement.

[0024] A rib is a raised portion of the tread in the radial direction, as opposed to a cut, which is recessed in the radial direction. Due to their delimitation by at least one circumferential cut, each rib extends substantially circumferentially. A rib may be circumferentially continuous or circumferentially discontinuous because it is interrupted by transverse cuts, whether these transverse cuts are blind or opening into at least one circumferential groove. We distinguish between so-called central ribs, delimited axially by two adjacent circumferential grooves, and so-called lateral ribs, delimited axially by one circumferential groove and by one of the axial edges of the tread surface. Each lateral rib is the outermost axial rib of the tread on each side of the tire's median plane.

[0025] A cut forms a space opening onto the tread surface and is formed from a circumferential, axial, or oblique radial cut in the tread. A cut has two main characteristics: a width and a curvilinear length such that the curvilinear length is at least twice the width. A cut is therefore delimited by at least two principal lateral faces, connected by a bottom face called the cut bottom, the two principal lateral faces being separated from each other by a non-zero distance called the cut width. A cut is such that the principal lateral faces cannot come into contact with each other, particularly when the tire is new. A cut oriented in a predominantly circumferential direction is called a "circumferential cut," and a cut oriented in a predominantly axial direction is called a "transverse cut."In cases where the main lateral faces can come into contact with each other, particularly when the tire is new, the cut is a circumferential, radial or oblique notch depending on the main direction of said notch.

[0026] In particular and optional embodiments, the singular axial zone includes a portion devoid of a first shrink-fit arrangement.

[0027] In particular and optional embodiments of the first object of the invention, the step-off zone is arranged axially between the first and second turning zones. In particular and optional embodiments of the second object of the invention, each circumferential arrival edge is arranged axially within each corresponding turning zone.

[0028] In particular and optional embodiments of the first variants, the second shrink-fit arrangement axially covers at least 75%, preferably at least 90%, of the axial width of the first shrink-fit arrangement. This particularly minimizes the axial width of the singular axial zone, thus facilitating an arrangement directly above the rib.

[0029] The tire has a substantially toroidal shape around an axis of revolution, substantially coinciding with the axis of rotation of the tire. This axis of revolution defines three directions classically used by those skilled in the art: an axial direction, a circumferential direction and a radial direction.

[0030] By axial direction, we mean the direction parallel to the axis of revolution of the tire, that is to say the axis of rotation of the tire.

[0031] By circumferential direction, we mean the direction which is perpendicular to the axial direction and to a radius of the tire.

[0032] By radial direction, we mean the direction along a radius of the tire, that is to say any direction intersecting the axis of rotation and perpendicular to this axis.

[0033] By meridian plane, we mean a plane containing the axis of rotation of the tire.

[0034] By median plane of the tire (denoted M), we mean the plane perpendicular to the axis of rotation of the tire and which passes through the axial midpoint of the tire.

[0035] By circumferential equatorial plane of the tire, we mean the theoretical cylindrical surface passing through the equator of the tire, perpendicular to the median plane and to the radial direction. The equator of the tire is, in a meridian cutting plane (plane perpendicular to the circumferential direction and parallel to the radial and axial directions), the axis parallel to the axis of rotation of the tire and located equidistant between the outermost radial point of the tread intended to be in contact with the ground and the innermost radial point of the tire intended to be in contact with a support, for example a rim.

[0036] By radially inside, and radially outside respectively, we mean closer to the axis of rotation of the tire, and further from the axis of rotation of the tire respectively. By axially inside, and axially outside respectively, we mean closer to the median plane of the tire, and further from the median plane of the tire respectively.

[0037] In preferred embodiments of the invention, the tires are intended for passenger vehicles as defined in the European Tyre and Rim Technical Organisation (ETRTO) standard, 2023. Preferably and optionally, such a tire has a cross-section in a meridional plane characterized by a section height H and a nominal section width or bead size S as defined in the European Tyre and Rim Technical Organisation (ETRTO) standard, 2023, such that the H / S ratio, expressed as a percentage, is at most 90 and at least 20, and the nominal section width S is at least 115 mm and at most 385 mm. Furthermore, the hook diameter D, defining the diameter of the tire mounting rim, is at least 12 inches and at most 30 inches.

[0038] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (i.e. excluding bounds a and b) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (i.e. including the strict bounds a and b).

[0039] In advantageous and optional embodiments, the singular axial zone is entirely arranged axially in line with the rib.

[0040] In other words, the axial width of the rib is strictly greater than the axial width of the singular axial zone. Thus, the singular axial zone is optimally protected.

[0041] The width of a rib on a new tire is the maximum distance measured between the two main lateral faces, in the case where the rib does not include a chamfer or fillet, at a radial height coinciding with the tread surface, and in the case where the cut includes a chamfer or fillet, at the innermost radial height of the cut and radially inner to the chamfer or fillet. The width is measured substantially perpendicular to the main lateral faces.

[0042] The width of the singular axial zone is determined as the maximum axial distance of the singular axial zone.

[0043] In advantageous and optional embodiments, the singular axial zone is arranged in an axial portion of the shrink-fitting frame centered on a median plane of the tire and extending axially over an axial width less than or equal to 30%, preferably 20% and more preferably 10% of the axial width of the tire's tread surface.

[0044] Thus, the position of the starting and / or finishing circumferential edge can be common for several tire sizes, particularly for tires with different tread widths. Therefore, by positioning the starting and / or finishing circumferential edge in the axial portion centered on the median plane, the axial position of the starting and / or finishing circumferential edge is no longer dependent on the tread width of the tire.

[0045] Conventionally, the tread surface is axially delimited by first and second axial edges coinciding respectively with the first and second axial edges of the tread. The axial width of the tread surface is the distance measured along the axial direction between the first and second axial edges. The first and second axial edges are determined on a tire mounted on a nominal rim and inflated to the nominal pressure as defined in the ETRTO 2023 standard manual. The first and second axial edges are arranged on either side of the median plane of the tire and are formed by lines substantially parallel to the circumferential direction of the tire. In the case of a clear boundary between the tread surface and the rest of the tire, the first and second axial edges are determined simply. In the case where the tread surface is continuous with the outer surfaces of the tire sidewalls, the following are determined: usually the first and second axial edges by loading the tire to 80% of its load capacity according to the ETRTO 2023 standard manual and the first and second axial edges are identified as the axial limits of the tread in contact with the ground.

[0046] In advantageous and optional embodiments, the singular axial zone is arranged vertically above the rib closest axially to the median plane.

[0047] Thus, advantageously, the shrink-fitting reinforcement approaches symmetry with respect to the median plane and allows the design of a particularly uniform tire whose high-speed performance is ensured while offering the desired protection against the penetration of corrosive agents.

[0048] In advantageous and optional embodiments, the portion of the third shrink-fit arrangement extends continuously and circumferentially over at least 75%, preferably at least 90% and more preferably 100% of the circumference of the tire.

[0049] Thus, advantageously, the positioning of the third shrink-fit arrangement arranged vertically above the rib closest axially to the median plane makes it possible to improve the performance of the tire in indentation tests.

[0050] To perform these indentation tests (called "breaking energy tests"), the tire assembly (tire mounted on a rim) is pressurized and successively rests on a series of standardized indenters (the cylindrical shape of the indenters has a height greater than its diameter, and the end of the side exposed to the tire tread is generally rounded). These tests quantify the energy (in Joules) required for the maximum permissible indentation of the tire assembly as a function of the applied load (in kilograms) and the vertical displacement (in mm) of the tire assembly toward the indenter. Such tests are described in standards such as FMVSS-139 proposed by the NHTSA (National Highway Traffic Safety Administration - USA), where the indenter must, in particular, be aligned with the protective raised element closest to the median plane.

[0051] In advantageous and optional embodiments, the portion of the third shrink-fit arrangement extends axially over at least 80% of the axial width of the rib closest axially to the median plane. This optimizes the tire's resistance to indentation.

[0052] In advantageous and optional embodiments, the singular axial zone is arranged in line with the rib having the lowest volumetric notching ratio or in line with one of the ribs having the lowest volumetric notching ratio.

[0053] Each rib is delimited by its two lateral faces and one face of the running surface. The total volume VT of each rib corresponds to the volume that would occupy The elastomeric material between the different faces described previously is in the theoretical case where each rib has no notches. Thus, we have the following relationship: VT = VE + VC, where VC is the volume of elastomeric material actually contained in each rib, and VE is the volume of notches in each rib. The ratio of the notch volume VE to the total volume VT determines a volumetric notching ratio TEV such that TEV = VE / VT.

[0054] Thus, by choosing such an arrangement, we prioritize a particularly improved protection of the top reinforcement by taking into account the volumetric notching rate of each rib.

[0055] In advantageous and optional embodiments, the strip, or each strip A and strip B, comprises at least one wire reinforcement element for shrinking.

[0056] Optionally, the wire reinforcement element or elements of the wire cage are textile.

[0057] A textile yarn reinforcing element is defined as at least one textile monofilament. Such monofilaments are obtained, for example, by melt spinning, solution spinning, or gel spinning. Textile monofilaments are usually classified into two main categories: natural monofilaments and chemical monofilaments. Natural monofilaments include monofilaments of plant origin (including cotton), animal origin, and mineral origin. Chemical monofilaments include artificial monofilaments and synthetic monofilaments. Artificial monofilaments are manufactured from natural raw materials and include, in particular, viscose made from wood cellulose. Synthetic monofilaments include organic polymeric monofilaments (e.g., polyesters and polyamides) as well as inorganic polymeric monofilaments (e.g., glass and carbon).For reasons of protection against corrosive agents, the textile monofilament(s) used here are preferably chosen from among chemical monofilaments, preferably from synthetic monofilaments, and most preferably from organic polymeric monofilaments. Examples include aliphatic polyamides, particularly polyamide 6-6, polyesters, particularly polyethylene terephthalate, and aromatic polyamides, particularly aramid.

[0058] Optionally, the wire reinforcement element(s) is also embedded in a polymer matrix, preferably an elastomeric matrix. The compositions used for these matrices are conventional compositions for calendering reinforcements, typically based on natural rubber or other diene elastomer, a reinforcing filler such as carbon black, a vulcanizing system, and standard additives. The adhesion between the element(s) of wire reinforcement and the matrix in which they are embedded is ensured for example by a usual adhesive composition, for example an RFL (Resorcinol-Formaldehyde-Latex) type glue or an equivalent glue, for example as described in WO2013017421 or WO2017168109.

[0059] In advantageous and optional embodiments, the tire comprises a carcass layer anchored in each bead, the carcass layer extending radially in each sidewall and extending radially inwardly to the crown reinforcement in the crown, the carcass layer comprising carcass wire reinforcement elements extending along a principal direction of each carcass wire reinforcement element forming, with the circumferential direction of the tire: - an angle, in absolute value, from 80° to 90° in a portion of the carcass layer extending radially in each sidewall, and - an angle strictly less than 80° in a portion of the carcass layer extending axially in the crown.

[0060] In advantageous and optional embodiments, the top reinforcement includes a working reinforcement comprising a single working layer.

[0061] The presence of a single working layer necessitates reinforcement of the tire's mechanical structure, a reinforcement notably provided by the shrink-fit reinforcement, which comprises the first and second shrink-fit arrangements. In addition to its shrink-fit function, the shrink-fit reinforcement absorbs a greater proportion of the tire's circumferential stresses during inflation, rolling, and centrifugal forces, and thus, through its drift stiffness, contributes more effectively to the tire's guiding function. Brief description of the figures

[0062] The invention and its advantages will be readily understood in light of the following non-limiting detailed description with reference to Figures 1 to 8, in which: - [Fig. 1] is a cross-sectional view in a meridian plane of a tire according to a first configuration of a first embodiment of the invention, the first embodiment corresponding to the first object described above, - [Fig. 2] is a top view of the tread of the tire of [Fig. 1] comprising circumferentially continuous ribs, - [Fig. 3] is a view similar to that of [Fig. 2] of a tire according to an alternative embodiment of the tread comprising circumferentially discontinuous ribs including transverse cutouts, - [Fig. 4] is a detail view of zone IV of [Fig. 1] illustrating a step-off zone of the tread, - [Fig.5] illustrates a schematic top view of the shrink-fit armature as well as a view in a meridian section plane AA' including the axis of rotation of the tire of [Fig.1], - [Fig. 6] is a view analogous to that of [Fig. 4] of a tire according to a second configuration of the first embodiment, and - Fig.7 and Fig.8 are views similar to that of Fig.4 of tires respectively according to first and second configurations of a second embodiment of the invention, the second embodiment corresponding to the second object described previously.

[0063] In the figures relating to the tire, a coordinate system X, Y, Z is shown, corresponding to the usual circumferential (X), axial (Y), and radial (Z) directions of a tire, respectively. Figure 1 shows a tire 1, conforming to the first variant of the first embodiment of the invention. The tire 1 is substantially of revolution about an axis substantially parallel to the axial direction Y. The tire 1 is intended for a passenger vehicle and has a tire size of 245 / 45R18. The tire 1 is intended to be mounted on a mounting support, for example, a rim.

[0064] The tire 1 includes a vertex 7 comprising a tread 33 comprising a tread surface 31 intended to come into contact with a road surface and a vertex reinforcement 13 extending into the vertex 7 in the circumferential direction X. The vertex reinforcement 13 and the tread 33 are arranged in contact with each other. The apex reinforcement 13 is arranged radially inside the tread 33. The tread 33 also has several circumferential cutouts 21. The tread 33 includes two circumferentially continuous lateral ribs 19A, 19E and circumferentially continuous central ribs 19B, 19C, 19D illustrated in [Fig.2], each axially delimited by at least one of the circumferential cutouts 21. Each rib 19A, 19B, 19D, 19E includes transverse cutouts 20 while rib 19C is devoid of transverse cutouts.Rib 19C is the rib closest axially to the median plane M and the one with the lowest notching ratio.

[0065] In one embodiment of the tread and with reference to [Fig. 3], the tread 33 comprises several circumferentially discontinuous ribs 25A, 25B, 25C, 25D, including transverse cutouts 39 creating a circumferential discontinuity in the rib. In this embodiment, ribs 25B and 25C are the ribs closest axially to the median plane M.

[0066] The tire 1 comprises two sidewalls 3 extending radially inwards from the apex 7. The tire 10 further comprises two beads 5 radially inwards from the sidewalls 3. Each sidewall 3 connects each bead 5 to the apex 7.

[0067] The top reinforcement 13 comprises a working reinforcement 15 and a shrink-fit reinforcement 17. The shrink-fit reinforcement 17 is arranged radially outside the working reinforcement 15 and radially inside the tread 33. The shrink-fit reinforcement 17 is therefore radially interposed between the working reinforcement 15 and the tread 33.

[0068] The tire 1 includes a carcass reinforcement 10 anchored in each bead 5. In this case, the carcass reinforcement 10 comprises at least one carcass layer 11 and here comprises a single carcass layer 11 wound around two beads 9. The carcass reinforcement 10, here the carcass layer 11, extends radially in each sidewall 3 and axially in the crown 7 radially internally to the crown reinforcement 13 in the crown 7. The crown reinforcement 13 is arranged radially between the tread 33 and the carcass reinforcement 10.

[0069] The carcass layer 11 comprises wire carcass reinforcement elements extending along a principal direction of each wire carcass reinforcement element forming, with the circumferential direction X of the tire 1, an angle, in absolute value, ranging from 80° to 90° in a portion of the carcass layer extending radially in each sidewall, and an angle strictly less than 80° in a portion of the carcass layer extending axially in the crown. Examples of such carcass layers are described in particular in WO2021074511.

[0070] The working reinforcement 15 comprises at least one working layer 16. Here, the working reinforcement 15 comprises a single working layer 16. Such working reinforcements are described in particular in WO2021074511.

[0071] The shrink-fitting frame 17 comprises a first shrink-fitting arrangement 45 in contact with the working frame 15 and a second shrink-fitting arrangement 46 in contact with the first shrink-fitting arrangement 45. The second shrink-fitting arrangement 46 is arranged radially externally to the first shrink-fitting arrangement 45.

[0072] The first shrink-fit arrangement 45 is arranged in contact with a bearing surface of the first shrink-fit arrangement 45 formed at least in part by a radially external surface 27 of the working frame 15 forming the bearing surface of the shrink-fit frame 17.

[0073] The second shrink-fit arrangement 46 is arranged in contact with a bearing surface of the second shrink-fit arrangement 46 formed at least in part by a radially external surface 28 of the first arrangement 45.

[0074] With reference to [Fig. 1], [Fig. 4] and [Fig. 5], in the first embodiment, the shrink-fit armature 17 comprises a single continuous wound strip 41 over several circumferential turns so as to form the first and second shrink-fit arrangements 45, 46. The second shrink-fit arrangement 46 axially covers at least 75%, preferably at least 90% of the axial width of the first shrink-fit arrangement 45.

[0075] The strip 41 comprises, a circumferential starting edge 43 and a circumferential ending edge 44, positioned in the vicinity of the median plane M as well as two longitudinal edges 54, 55.

[0076] The strip 41 here comprises eight to ten wire reinforcement elements embedded in an elastomeric matrix to form a strip with a width ranging from 5.0 mm to 15.0 mm and a thickness ranging from 0.5 mm to 1.0 mm. Each wire reinforcement element comprises two multifilament strands of aromatic polyamide and one strand of polyester, for example as described in WO2021074511.

[0077] The first shrink-fit arrangement 45 comprises a first portion 47 of the first shrink-fit arrangement 45 and a second portion 49 of the first shrink-fit arrangement 45. The second shrink-fit arrangement 46 comprises a first portion 51 of the second shrink-fit arrangement 46 and a second portion 53 of the second shrink-fit arrangement 46.

[0078] For the sake of clarity in [Fig. 5] to [Fig. 8], vertical hatching represents the second arrangement, while oblique hatching represents the first arrangement. For example, each turning zone includes an uncovered portion of the first shrink-fit arrangement, which is therefore represented by oblique hatching. Finally, the bearing surface 27 formed by the radially outer surface of the single working layer 16 is shown without hatching.

[0079] The first portion 47 of the first shrink-fit arrangement 45 is in contact with the bearing surface 27 and extends axially from the circumferential starting edge 43 to a first reversal zone 59A of the strip 4L. The first reversal zone 59A corresponds to a first change in the axial winding direction of the strip 4L.

[0080] The first portion 51 of the second shrink-fit arrangement 46 is in contact with the first portion 47 of the first shrink-fit arrangement 45 and extends axially from the first reversible zone 59A to a step-off zone 57 of the strip 4L

[0081] The second portion 49 of the first shrink-fit arrangement 45 is in contact with the bearing surface 27 and axially extends the first portion 51 of the second shrink-fit arrangement 46 from a step-off zone 57 of the strip 41 to a second reversal zone 59B of the strip 4L. The second reversal zone 59B corresponds to a second change in the axial winding direction of the strip 4L.

[0082] The second portion 53 of the second shrink-fit arrangement 46 is in contact with the second portion 49 of the first shrink-fit arrangement 45 and extends axially from the second turning zone 59B to the circumferential arrival edge 44.

[0083] The detachment zone 57 is arranged axially between the first and second reversing zones 59A, 59B.

[0084] As illustrated in [Fig.5], the shrink-fit armature 17 includes a singular axial zone ZI comprising the circumferential starting edge 43 and the circumferential ending edge 44. In the first configuration of the first embodiment, the singular axial zone ZI includes a portion 65 of the first shrink-fit arrangement 45 in which the first shrink-fit arrangement 45 is not radially covered by the second shrink-fit arrangement 46.

[0085] Portion 65 is said to be under-thick. Indeed, as can be seen in [Fig.5], portion 65 has a thickness strictly less than the thickness of the assembly of the first and second arrangements 45, 46.

[0086] The singular axial zone ZI is arranged in an axial portion centered on a median plane M of the tire and extends axially over an axial width less than or equal to 30%, preferably 20% and more preferably 10% of the axial width of the tread surface 31 of the tire 1.

[0087] With reference to [Fig. 1] and [Fig. 2], the singular axial zone ZI is arranged axially partly perpendicular to one of the ribs 19A to 19E and here entirely arranged perpendicular to rib 19C. With reference to [Fig. 5], the portion 65 of the first shrink-fit arrangement 45 comprises a portion 65A arranged circumferentially between the starting and ending edges 43, 44, as well as portions 65B extending from the step-off zone 58 to each longitudinal edge 54, 55 of the strip 4L

[0088] We will now describe a second configuration of the first embodiment with reference to [Fig. 6] by difference with respect to the pneumatic version according to the first variant of the first embodiment. Elements analogous to those described previously are designated by identical reference numerals.

[0089] In the second configuration of the first embodiment, the shrink-fitting frame 17 includes a third shrink-fitting arrangement 48 arranged radially externally to the second shrink-fitting arrangement 46. The singular axial zone ZI includes a portion 67 of the third shrink-fitting arrangement 48.

[0090] Portion 67 is said to be thicker. Indeed, as can be seen in [Fig.6], portion 67 has a thickness strictly greater than the thickness of the assembly of the first and second arrangements 45, 46.

[0091] In addition, the singular axial zone ZI comprises a portion 65 of the first shrink-fit arrangement 45 not radially covered by the second shrink-fit arrangement 46 extending here from the step-off zone 57 to each end zone 54 of the strip 41.

[0092] Just as in the first configuration, the singular axial zone ZI is arranged axially partly in line with one of the ribs 19A to 19E and here entirely arranged in line with rib 19C.

[0093] We will now describe a first configuration of the second embodiment with reference to [Fig. 7] by contrasting it with the configurations described previously. Elements analogous to those described previously are designated by identical reference numerals.

[0094] The shrink-fit armature 17 of the first configuration of the second embodiment comprises a separate strip A and a strip B, i.e., not continuous with each other. Each strip A and strip B is continuous and wound on several circumferential turns so as to form the first and second arrangements 45, 46. Each strip A and strip B comprises respectively a circumferential starting edge 43A, 43B and a circumferential ending edge 44A, 44B positioned here in the vicinity of the median plane M.

[0095] The first portion 47 of the first shrink-fit arrangement 45, in contact with the bearing surface 27, comprises several circumferential turns of the strip A and extends axially from the starting circumferential edge 43A to a turning zone 59A of the strip A. The first portion 51 of the second shrink-fit arrangement 46 comprises several circumferential turns of the strip A and extends axially from the turning zone 59A to the ending circumferential edge 44A.

[0096] The second portion 49 of the first shrink-fit arrangement 45, in contact with the bearing surface 27, comprises several circumferential turns of the strip B and extends axially from the starting circumferential edge 43B to a turning zone 59B of the strip B. The second portion 53 of the second shrink-fit arrangement 46 comprises several circumferential turns of the strip B and extends axially from the turning zone 59B to the ending circumferential edge 44B.

[0097] Each circumferential arrival edge 44A, 44B is arranged axially inside each corresponding turning zone 59A, 59B.

[0098] The shrink-fitting frame 17 includes a singular axial zone ZI comprising a portion 65 of the first shrink-fitting arrangement 45 in which the first shrink-fitting arrangement 45 is not radially covered by the second shrink-fitting arrangement 46. In this case, the portion 65 of the first shrink-fitting arrangement 45 comprises four portions 65C, 65D, 65E and 65F extending between the step-off zone 57A, the longitudinal edge 54A and the step-off zone 57B and the longitudinal edge 55B. The singular axial zone ZI also includes here a portion 66 lacking a first clamping arrangement 45.

[0099] Just as in the previous configurations, the singular axial zone Zlest is arranged axially partly in line with one of the tread ribs.

[0100] We will now describe a second configuration of the second embodiment with reference to [Fig. 8] by contrasting it with the configurations previously described. Elements analogous to those described previously are designated by identical reference numerals.

[0101] The shrink-fitting frame 17 comprises a third shrink-fitting arrangement 48 arranged radially externally to the second shrink-fitting arrangement 46. The singular axial zone ZI comprises a portion 67 of the third shrink-fitting arrangement 48 in which the third shrink-fitting arrangement 48 radially overlaps the second shrink-fitting arrangement 46. The portion 67 is arranged circumferentially between the circumferential starting edge 43A of the strip A and the circumferential ending edge 44B of the strip B. The portion 67 of the third shrink-fitting arrangement 48 is here formed by a portion of the strip B which partially overlaps the first portion 47 of the first shrink-fitting arrangement 45 and partially overlaps the first portion 51 of the second shrink-fitting arrangement 46.

[0102] The singular axial zone ZI also includes a portion 65H, 651 of the first shrink-fit arrangement 45 in which the first shrink-fit arrangement 45 is not covered by the second shrink-fit arrangement 46.

[0103] Just as in the previous configurations, the singular axial zone Zlest is arranged axially partly in line with one of the tread ribs.

[0104] The invention is not limited to the configurations and embodiments previously described.

[0105] In particular, the structure constituting the strip is not limited to that described above. Other wire reinforcement elements for the shrink-fitting may be considered in addition to those described. A strip made from cut wire reinforcement elements may also be considered.

[0106] It may also be possible to consider sculptures more complex than those described above and including in particular circumferential cutouts presenting general directions of varying size.

[0107] Embodiments in which the working reinforcement comprises two working layers may also be considered. Such working reinforcements and associated frame reinforcements are described in particular in WO2021250331.

[0108] Unlike the configurations and embodiments described above in which the winding pitch of the strip is substantially equal to the width of the strip, embodiments may be considered in which the winding pitch of the strip is strictly greater or strictly less than the width of the strip, and this over all or part of the top.

[0109] It may also be envisaged that embodiments may be envisaged in which, contrary to the second configuration of the first embodiment illustrated in [Fig.6] in which the portion 67 of the third shrink-fit arrangement 48 is relatively reduced, the portion 67 of the third shrink-fit arrangement 48 extends continuously and circumferentially over at least 75%, preferably at least 90% and more preferably 100% of the circumference of the tire.

[0110] The tires described above can be obtained by a tire manufacturing process known elsewhere. The process includes a step of forming an intermediate blank lacking the shrink-fit reinforcement and the tread. This forming step is carried out on a forming support. The process also includes a helical winding step of the strip.

[0111] In a first variant, the helical winding step of the strip is done directly on the intermediate blank.

[0112] In a second embodiment, the helical winding step of the strip is carried out on a winding support separate from the forming support and separate from the blank. The winding support includes a strip anchoring device for anchoring the strip at an anchor point located axially near the median plane of the winding support. Such an anchoring device is described, for example, in document FR3083475. The process then includes a step of transferring the helical winding of the strip to the intermediate blank by means of a transfer device. Such a transfer device is described, for example, in document EP3554817.

[0113] Thanks to the positioning of the starting edge of the strip(s) in the vicinity of the median plane, the only parameters to modify to determine the axial width of the shrink-fit reinforcement are the positions of the turning zones, or in other words, the number of turns required to reach the turning zones. Thus, when two tires have shrink-fit reinforcements with different axial widths, for example, because the tires have different cross-sectional widths, it is possible to use the same process and devices described above for both tires by changing only the parameters indicated previously.

[0114] In the first embodiment, a person skilled in the art will be able to take a relevant reference point on the intermediate blank and / or the assembly of the winding device relative to the winding device to position the starting edge of the strip. In the second embodiment, a person skilled in the art will be able to take a relevant reference point on the winding device and / or the winding support and / or the wound shrink-wrap assembly relative to the intermediate blank and / or the assembly of the winding device to position the starting edge of the strip.

Claims

1. Demands A tire (1) comprising a crown (7), two sidewalls (3), two bead ribs (5), each sidewall (3) connecting each bead rib (5) to the crown (7), the crown (7) comprising a tread (33) comprising at least one rib (19), the crown (7) comprising a crown reinforcement (13) comprising a shrink-fit reinforcement (17) arranged radially inside the tread (33), the shrink-fit reinforcement (17) comprising a strip (41) wound in several circumferential turns so as to form first (45) and second (46) shrink-fit arrangements and comprising a circumferential starting edge (43) and a circumferential finishing edge (44), the second shrink-fit arrangement (46) being arranged radially external to the first shrink-fit arrangement (45), a first portion (47) of the first shrink-fit arrangement (45) extending axially to starting from the circumferential starting edge (43) to a first turning zone (59A) of the strip (41),a first portion (51) of the second shrink-fit arrangement (46), in contact with the first portion (47) of the first shrink-fit arrangement (45), extending axially from the first turning zone (59A) to a step-off zone (57) of the strip (41), a second portion (49) of the first shrink-fit arrangement (45) extending axially from the first portion (51) of the second shrink-fit arrangement (46) from the step-off zone (57) to a second turning zone (59B) of the strip (41), a second portion (53) of the second shrink-fit arrangement (46), in contact with the second portion of the first shrink-fit arrangement (49), extending axially from the second turning zone (59B) to the circumferential arrival edge (44), characterized in that the shrink-fit reinforcement (17) comprises an axial zone singular (Zl) comprising the circumferential starting edge (43) and / or arrival edge (44) and comprising:, - a portion (65) of the first shrink-fit arrangement (45) in which the first shrink-fit arrangement (45) is not radially covered by the second shrink-fit arrangement (46), and / or

2. - a portion (67) of a third shrink-fit arrangement (48) in which the third shrink-fit arrangement (48) radially covers the second shrink-fit arrangement (46), and in that the singular axial zone (Zl) is partly arranged axially in line with at least one rib (19). Tire (1) comprising a crown (7), two sidewalls (3), two bead ribs (5), each sidewall (3) connecting each bead rib (5) to the crown (7), the crown (7) comprising a tread (33) comprising at least one rib (19), the crown (7) comprising a crown reinforcement (13) comprising a shrink-fit reinforcement (17) arranged radially inside the tread (33), the shrink-fit reinforcement (17) comprising a strip A and a strip B wound over several circumferential turns so as to form first (45) and second (46) shrink-fit arrangements, each strip A and strip B comprising a circumferential starting edge (43A, 43B) and circumferential finishing edge (44A, 44B), the second shrink-fit arrangement (46) being arranged radially externally to the first shrink-fit arrangement (45),a first portion (47) of the first shrink-fit arrangement (45) comprising several circumferential turns of the strip A and extending axially from the starting circumferential edge (43A) of the strip A to a turning zone (59A) of the strip A, a first portion (51) of the second shrink-fit arrangement (46), in contact with the first portion (47) of the first shrink-fit arrangement (45), comprising several circumferential turns of the strip A and extending axially from the turning zone (59A) of the strip A to the ending circumferential edge (44A) of the strip A, a second portion (49) of the first shrink-fit arrangement (45) comprising several circumferential turns of the strip B, and extending axially from the starting circumferential edge (43B) of the strip B to a turning zone (59B) of strip B, a second portion (53) of the second shrink-fit arrangement (46),in contact with the second portion (49) of the first shrink-fit arrangement (45), comprising several circumferential turns of, strip B and extending axially from the turning zone (59B) of strip B to the circumferential arrival edge (44B) of strip B, characterized in that the shrink-fit reinforcement (17) comprises a singular axial zone (Zl), comprising at least one of the circumferential starting edges (43A, 43B) and / or arrival edges (44A, 44B) of strip A or strip B and comprising: - a portion (65A, 65B) of the first shrink-fit arrangement (45) in which the first shrink-fit arrangement (45) is not radially covered by the second shrink-fit arrangement (46) and / or - a portion (67) of a third shrink-fit arrangement (48) in which the third shrink-fit arrangement (48) radially covers the second shrink-fit arrangement (46), and in that the axial zone singular (Zl) being partly arranged axially in line with at least one rib (19).

3. Pneumatic (1) according to any one of the preceding claims, wherein the singular axial zone (Zl) is fully arranged axially in line with at least one rib (19).

4. Tire (1) according to any one of the preceding claims, wherein the singular axial zone (Zl) is arranged in an axial portion of the shrink-fitting frame centered on a median plane (M) of the tire and extending axially over an axial width less than or equal to 30%, preferably 20% and more preferably 10% of the axial width of the tread surface of the tire (1).

5. Pneumatic (1) according to any one of the preceding claims, wherein the singular axial zone (Zl) is arranged vertically above the rib (19) closest axially to the median plane (M).

6. Tire (1) according to any one of the preceding claims, wherein the portion (67) of the third shrink-fit arrangement (48) extends continuously and circumferentially over at least 75%, preferably at least 90% and more preferably 100% of the circumference of the tire.

7. Pneumatic (1) according to any one of the preceding claims, wherein the singular axial zone (Zl) is arranged at the vertical line of the rib (19) having the lowest notching rate or vertically of one of the ribs (19) having the lowest notching rate.

8. Pneumatic (1) according to any one of the preceding claims, wherein the strip (41) or each strip A and strip B comprises at least one wire reinforcement element for shrinking.

9. A tire (1) according to any one of the preceding claims, comprising a carcass layer (11) anchored in each bead, the carcass layer extending radially in each sidewall and extending radially inwardly to the crown reinforcement in the crown, the carcass layer (11) comprising carcass wire reinforcement elements extending along a principal direction of each carcass wire reinforcement element forming, with the circumferential direction of the tire: - an angle, in absolute value, from 80° to 90° in a portion of the carcass layer extending radially in each sidewall, and - an angle strictly less than 80° in a portion of the carcass layer extending axially in the crown.

10. Pneumatic (1) according to any one of the preceding claims, wherein the top reinforcement comprises a working reinforcement (15) comprising a single working layer.

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