Tyre and method for manufacturing such a tyre
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
- Filing Date
- 2026-01-22
- Publication Date
- 2026-08-06
Smart Images
Figure EP2026051541_06082026_PF_FP_ABST
Abstract
Description
[0001] Pneumatics and the manufacturing process of such a pneumatic
[0002] The present invention relates to a tire, as well as a method for manufacturing such a tire.
[0003] The invention relates in particular, but not exclusively, to tires for light vehicles, such as passenger vehicles, including four-wheeled and two-wheeled vehicles, and vans. A tire is defined as a band designed to form a cavity by cooperating with a mounting support, commonly referred to as a "rim," this cavity being capable of being pressurized to a pressure greater than atmospheric pressure. The tire has a substantially toroidal structure of revolution around an axis of revolution, which coincides with an axis of rotation around which the tire can rotate to roll on the ground. This axis of revolution defines three directions: an axial direction, a circumferential direction, and a radial direction, conventionally used by those skilled in the art to describe the tire according to the following conventions:
[0004] - by axial direction, we mean the direction substantially parallel to the axis of revolution of the tire, that is to say the axis of rotation of the tire;
[0005] - by radial direction, we mean the direction along a radius of the tire, that is to say any direction intersecting the axis of rotation of the tire and substantially perpendicular to this axis;
[0006] - by circumferential direction, we mean the direction which is substantially perpendicular to both the axial direction and to a radius of the tire; in other words, the circumferential direction is tangent to a circle whose center is on the axis of rotation of the tire; the circumferential direction is thus tangent to a tread surface of the tire;
[0007] - by median plane, we mean the plane perpendicular to the axis of rotation of the tire, which passes through the axial midpoint of the tire's rolling surface;
[0008] - by meridian plane, we mean a plane containing the axis of rotation of the tire, the meridian plane thus being perpendicular to the circumferential direction;
[0009] - by radially inside, respectively radially outside, we mean closer to the axis of rotation of the tire, respectively further from the axis of rotation of the tire; and- by axially inside, respectively axially outside, we mean closer to the median plane of the tire, respectively further from the median plane of the tire.
[0010] Typically, a tire consists of a crown, which radially forms the outer tread that contacts the ground as the tire rolls. This crown extends radially inward, on either side of the tire's median plane, into the first and second sidewalls, and then into the first and second bead sections that contact the wheel rim. The crown, the first and second sidewalls, and the first and second bead sections define a toroidal inflation cavity for the tire. A bead section is the radial portion of the tire designed to secure it to the rim. Each bead section is specifically designed to engage with a rim hook for this purpose.Each bead is thus delimited radially internally by the innermost radial end of the tire and radially externally by an axial line passing through the outermost radial point in contact with a standard nominal rim as defined by the European Tyre and Rim Technical Organisation (ETRTO) standard, 2023. Furthermore, sidewalls are defined as the radial portions of the tire connecting the beads to the crown. Each sidewall is delimited radially externally by an edge of the tread. The axial edges of the tread are determined on a tire mounted on a nominal rim and inflated to the nominal pressure as defined by ETRTO, 2023. The edges are arranged on either side of the tire's median plane and formed by lines substantially parallel to the tire's circumferential direction.In the case of a clear boundary between the tread and the sidewalls of the tire, the edges are easily determined. Where the tread is continuous with the sidewalls, the edges are usually determined by loading the tire to 80% of its load capacity according to ETRTO 2023. The edges are identified as the axial limits of the tread in contact with the ground. Each sidewall is delimited radially on its inner side by an axial line passing through the outermost radial point in contact with a standard nominal rim as defined by ETRTO 2023.
[0011] For reinforcement purposes, the tire has a carcass reinforcement, which is anchored in each of the beads and extends from the beads in the sidewalls to the crown. In addition, the crown often includes a crown reinforcement, which strengthens the crown and is arranged radially between the tread and the carcass reinforcement.
[0012] The invention relates to tires whose carcass structure includes at least one layer of carcass, referred to as a "reversed" layer, which is anchored in each bead by being reversed, from the inside to the outside of the tire, around a bead of the corresponding bead, allowing the tire to be attached to the rim. This reversed carcass layer thus forms both a main part, which extends from one or both of the beads respectively in the sidewalls to the crown, and two reversals, which are arranged axially outside the main part and which extend from the main part to two edges of the reversed carcass layer, respectively, axially opposed to each other.Each of these two edges of the inverted carcass layer is arranged in the corresponding bead and / or sidewall of the tire, being enveloped by one or more elastomeric layers of the tire, that is to say, one or more layers made of an elastomeric compound. By "elastomeric" compound, layer, or matrix, we mean a material that consists mainly by weight of one or more diene elastomers, of the natural or synthetic rubber type, and which generally also includes, in the matrix formed by this or these diene elastomers, fillers and other components commonly used in tire compounds, such as at least one reinforcing filler of the carbon black and / or silica type, a crosslinking system most often sulfur-based, and protective agents.
[0013] The invention relates more specifically to tires whose inverted carcass layer comprises textile thread reinforcements, extending lengthwise from one edge of the inverted carcass layer to the other and usually encased along their length in an elastomeric coating matrix. Unless the carcass reinforcement includes another carcass layer which, in the sidewalls and bead sections, is arranged axially outside the two edges of the inverted carcass layer, the elastomeric layer(s) that respectively encase these two edges of the inverted carcass layer are usually dimensioned with a significant thickness towards the outside of the tire.In this way, each edge of the inverted carcass layer is kept away from the rim hook by the considerable thickness of the aforementioned elastomeric layer(s), which, in use, limits mechanical stresses, particularly compression, and therefore the deterioration of the interface between each of these edges and the aforementioned elastomeric layer(s). Although effective, this approach nevertheless increases the tire's weight and production cost.
[0014] An alternative approach involves adding, between the outer axial side of each of the two edges of the inverted carcass layer and the aforementioned elastomeric layer(s), a rim strip comprising a reinforcement embedded in an elastomeric compound. However, these added rim strips increase the number of parts to be assembled within the tire and complicate tire manufacturing, thereby increasing its production cost.
[0015] The aim of the present invention is to propose a tire which, while effectively limiting the risks of deterioration of the interfaces between the edges of its inverted carcass layer and the elastomeric layers enveloping these edges, is improved with regard to, among other things, its cost price.
[0016] To this end, the invention relates to a tire comprising a crown, two sidewalls each extending radially inward from the crown, two bead ribs extending radially inward from the two sidewalls respectively and each comprising a bead for attaching the tire to a rim, and a carcass reinforcement extending from each bead rib in the sidewalls to the crown. The carcass reinforcement comprises a layer of carcass called the "reversed" layer, which (i) is anchored in each bead by being reversed around the bead of the corresponding bead so that the reversed carcass layer forms a main part extending from each bead rib in the sidewalls to the crown, and two reversals,(ii) are arranged axially outside the main part and extend from the main part to two axially opposed edges of the inverted carcass layer, respectively arranged in the ribs and / or sidewalls; (iii) delineate, on each of its edges, an end slice that is wrapped by at least one elastomeric layer of the tire; and (iv) include textile wire reinforcements that extend lengthwise from one edge of the inverted carcass layer to the other and are, on the end slice of each edge of the inverted carcass layer, transversely interrupted to form respective end sections of the textile wire reinforcements that are exposed to the rest of the inverted carcass layer. The tire further comprises, for each edge of the inverted carcass layer,an adhesive interlayer which is interposed between the end edge of the inverted carcass layer and said at least one corresponding elastomeric layer, by gluing the respective sections of the textile wire reinforcements.
[0017] One of the ideas behind the invention is to prevent interfacial damage, particularly cracking, from initiating on the respective end edges of the two edges of the inverted carcass layer. To achieve this, the invention provides for interposing, between the end edge of each of the two edges of the inverted carcass layer and the elastomeric layer(s) of the tire that encase this edge, an adhesive interlayer which, on this end edge, bonds the respective sections of the textile thread reinforcements of the inverted carcass layer.
[0018] The inventors have indeed identified that, in the absence of dedicated gluing, at least some of the sections of the textile wire reinforcements, which result from the interruption of the latter on the end edge of each of the two edges of the inverted carcass layer and which are exposed there vis-à-vis the rest of the inverted carcass layer, lack structural cohesion, in the sense that, while one or more textile monofilaments of each textile wire reinforcement remain, over substantially the entire length of the textile wire reinforcement, united to each other and to an elastomeric matrix coating the inverted carcass layer, this or these textile monofilaments of each textile wire reinforcement tend to separate from each other and / or from the elastomeric matrix coating at the level of the two opposite end sections of the textile wire reinforcement.In practice, this intrinsic decohesion of each textile wire reinforcement, located at the level of its end sections, can result from an operation of preparing a carcass sheet intended to form the reversed carcass layer, which is implemented upstream of the assembly of this carcass sheet with the rest of the parts constituting the tire and which typically consists of cutting this carcass sheet from a master strip and, thereby, cutting the textile wire reinforcements transversely, forming the aforementioned sections of the latter.
[0019] In all cases, the inventors have established, through tests and observations, that by gluing, that is to say by coating with glue, the end sections of the textile wire reinforcements and thus forming the aforementioned adhesive interlayer between the end edge of each edge of the reversed carcass layer and the surrounding elastomeric layer(s) of the tire, the decohesion mentioned above is neutralized.The inventors have indeed observed that such a bonding makes it possible, when using the tire according to the invention, to significantly limit, or even prevent, cracks and, more generally, structural deterioration from initiating through the end sections of the textile wire reinforcements at the interface between the edges of the inverted carcass layer and the rest of the tire, which is surprising at first glance given that the intrinsic mechanical resistance of this bonding is a priori low compared to the intense stresses to which the edges of the inverted carcass layer are subjected during the use of the tire.Without wishing to be bound by any theory or preconceptions, the inventors consider that by limiting or preventing such initiation of damage, in particular cracking, one subsequently avoids the coalescence between the deteriorations / cracks respectively linked to the textile wire reinforcements on the end edge of each of the edges of the inverted carcass layer, and therefore the occurrence of macro-damage which can propagate to the outer face of the tire, including when the elastomeric layer(s) of the tire which envelop the edges of the inverted carcass layer have a limited thickness.
[0020] Thanks to the aforementioned bonding process, the tire according to the invention makes it possible to reconcile (i) a limited risk of deterioration of the interfaces between the edges of the inverted carcass layer and the elastomeric layers of the tire that encase these edges, and (ii) a low production cost, due to the absence of oversizing the thickness of these elastomeric layers and the inherently low cost of the adhesive used for bonding. By avoiding oversizing the thickness of the aforementioned elastomeric layers, the mass of the tire is advantageously reduced. Furthermore, by limiting the risk of deterioration of the aforementioned interfaces, the invention advantageously makes it possible, for the carcass reinforcement, to avoid using, in addition to the inverted carcass layer, a carcass layer that, in the sidewalls and bead sections, is arranged axially outside the two edges of the inverted carcass layer.
[0021] In practice, the tire according to the invention can be manufactured by any suitable process. That being said, advantageously, the invention also relates to a process for manufacturing a tire according to the foregoing, in which:
[0022] - in a parent strip comprising textile thread reinforcements intended to form the textile thread reinforcements of the inverted carcass layer, a sheet of carcass intended to form the inverted carcass layer is cut so as to delimit the sheet of carcass by two selvedges, which are intended to form respectively the two edges of the inverted carcass layer and at each of which the textile thread reinforcements of the parent strip are cut transversely forming respective sections of the textile thread reinforcements of the parent strip, which are exposed vis-à-vis the rest of the carcass sheet, then
[0023] - around a cylindrical support centered on an axis, the carcass sheet is wound so that the edges of the carcass sheet extend circumferentially to the axis, then
[0024] - while the cylindrical support carries the carcass layer, the rods are brought axially around the carcass layer between the two edges of the carcass layer, then
[0025] - while the cylindrical support carries the carcass layer and the rods, a portion of the carcass layer is folded around each rod, the two folded portions of the carcass layer including respectively the two edges of the carcass layer and being intended to form respectively the two folds of the folded carcass layer, then
[0026] - each edge of the carcass layer is wrapped by at least one elastomeric strip, arranged around the corresponding folded part of the carcass layer and intended to form at least partially said at least one corresponding elastomeric layer.
[0027] Furthermore, after cutting the carcass layer from the parent strip and before wrapping the edges of the carcass layer with the elastomeric strips, at each edge of the carcass layer, at least the respective sections of the textile wire reinforcements of the parent strip are covered with a sizing agent intended to form each adhesive interlayer.
[0028] The process according to the invention makes it possible to manufacture the tire of the invention easily and economically. In particular, the process according to the invention differs advantageously from existing manufacturing processes only in one step, where each edge of the carcass ply is glued, and the implementation of this step has no significant impact on the implementation of the other steps of the process.
[0029] Advantageous aspects of the invention will be detailed later, in particular in connection with the nature of the glue used for bonding, with specificities of the textile thread reinforcements of the reversed carcass layer, with dimensional and structural specifications of the carcass reinforcement, etc. Thus, according to advantageous optional characteristics of the tire and / or the manufacturing process according to the invention, taken individually or according to all technically possible combinations: - each adhesive interlayer is made of a latex glue, in particular resorcinol-formaldehyde latex, or a cyanoacrylate glue;
[0030] - each textile wire reinforcement consists of one or more monofilaments of polyester, in particular polyethylene terephthalate, and / or aliphatic polyamide, in particular nylon, and / or aromatic polyamide, in particular aramid, and / or rayon;
[0031] - each textile wire reinforcement has a diameter ranging from 0.4 mm to 1.0 mm; - the end edge of each of the edges of the inverted carcass layer is located at a radial distance from the radially innermost point of the corresponding bead, this radial distance being between 0.1*H and 0.95*H, preferably between 0.1*H and 0.4*H, where H is the section height of the tire as defined in the ETRTO 2023 standard;
[0032] - each edge of the inverted carcass layer is axially separated from an external face of the tire exclusively by an elastomeric mass of the tire;
[0033] - the carcass reinforcement consists of the reversed carcass layer; - the carcass reinforcement also includes a so-called non-reversed carcass layer, which is totally arranged radially outside the rods and axially inside the reversals;
[0034] - a ratio, expressed as a percentage, between the section height and the nominal section width of the tire as defined in the ETRTO 2023 standard is at most equal to 90 and is at least equal to 20, and in which the nominal section width is at least equal to 115 mm and at most equal to 385 mm.
[0035] The invention will be better understood upon reading the following description, given solely by way of example and with reference to the drawings in which:
[0036] - Figure 1 is a schematic section of a tire according to the invention, this section being in a cutting plane corresponding to a meridian plane of the tire;
[0037] - Figure 2 is a larger scale view of the circled detail II in Figure 1; - Figure 3 is a partial schematic section along line lll-lll of Figure 2;
[0038] - Figure 4 is a partial schematic cross-section along line IV-IV of Figure 3;
[0039] - Figures 5 to 9 are diagrams illustrating successive operations of a manufacturing process for the tire in the preceding figures; and - Figures 10 and 11 are views similar to Figure 1, illustrating respectively two variants of the tire, according to the invention.
[0040] Figures 1 to 4 show a tire 100 and a geometric coordinate system whose X, Y, and Z directions correspond respectively to the radial, axial, and circumferential directions of the tire 100, as defined in the introductory section of this document. The tire 100 has a substantially toroidal shape around an axis of revolution, which is substantially parallel to the axial direction Y and coincides with an axis of rotation of the tire 100 around which the latter can be driven to rotate and roll on the ground.
[0041] In Figure 1, the tire 100 is associated with a nominal rim 10, as defined by the European Tyre and Rim Technical Organisation (ETRTO) standard, 2023, on which the tire 100 can be mounted, as schematically illustrated by the dotted lines. The rim 10 thus forms a mounting surface for the tire 100.
[0042] The 100 tire is preferably intended for passenger vehicles as defined by ETRTO 2023. Such a tire has a cross-section in a meridian plane, such as that schematically illustrated in Figure 1, which is characterized by a section height H and a nominal section width S, as defined by ETRTO 2023. The section height H and the nominal section width S are as indicated in Figure 1, their respective definitions being detailed later. In practice, the values of S and H are generally indicated on the tire sidewall marking. Preferably, the 100 tire is 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.Also preferentially, the diameter at the hook of the tire 100, defining the diameter of the nominal rim 10 on which the tire is mountable, is at least equal to 12 inches and at most equal to 30 inches.
[0043] As schematically represented in Figure 1, the tire 100 comprises a crown 110 having a tread 111, intended to come into contact with the ground during the rolling of the tire 100. Along the circumferential direction Z, the tread 111 extends over the entire circumference of the tire 100, and along the axial direction Y, the tread 111 extends on either side of a median plane M of the tire 100, this median plane M being as defined in the introductory section of this document. The crown 110 also includes, for the purpose of its reinforcement, a crown reinforcement 112 which extends within the crown 110 along the circumferential direction Z over the entire circumference of the tire 100, being radially superimposed on the tread 111.The top reinforcement 112 here includes a working reinforcement 113, which comprises, or is made up of, at least one working layer and which, here, consists of two radially superimposed working layers 114 and 115. In practice, each of the working layers 114 and 115:
[0044] - is axially delimited by two axial edges of the relevant working layer, arranged axially on either side of the median plane M, and
[0045] - includes wire reinforcements, not detailed in the figures, which are embedded in an elastomeric matrix of the relevant working layer, and which extend lengthwise from one to the other of the axial edges of the relevant working layer in a substantially parallel manner to each other along a principal direction forming, with the circumferential direction Z of the tire 100, an angle ranging, in absolute value, from 10° to 50°, it being noted that the angle associated with the working layer 114 and that associated with the working layer 115 have respective orientations which are opposite to each other.
[0046] The structural and dimensional specifications of the wire reinforcements in each of the working layers 114 and 115 are not limiting. Thus, each of these wire reinforcements can be made of metal and / or textile.
[0047] In the embodiment considered here, the top reinforcement 112 also includes a shrink-fit reinforcement 116, which comprises, or is made up of, at least one shrink-fit layer and which, here, consists of a single shrink-fit layer 117. The shrink-fit reinforcement 116, here the shrink-fit layer 117, is arranged radially outside the working reinforcement 113 and is therefore radially interposed between the working reinforcement 113 and the tread 111. In practice, the shrink-fit reinforcement 116, here the shrink-fit layer 117:
[0048] - is axially delimited by two axial edges of the shrink-fit reinforcement, arranged axially on either side of the median plane M, and
[0049] - includes one or more wire reinforcements, not detailed in the figures, which are embedded in an elastomeric matrix of the shrink-fit reinforcement, and which are circumferentially wound in a helix from one to the other of the axial edges of the shrink-fit reinforcement extending lengthwise along a principal direction forming, with the circumferential direction Z of the tire 100, an angle which, in absolute value, is less than or equal to 10°, preferably less than or equal to 5°.
[0050] The structural and dimensional specifications of the wire reinforcement(s) of the shrink-fit reinforcement 116, here of the shrink-fit layer 117, are not limiting. Thus, each of these wire reinforcements can be made of metal and / or textile. The tire 100 further comprises two sidewalls 120A and 120B, each of which extends radially inwards from the apex 110 and which are arranged axially on either side of the median plane M.
[0051] The 100 tire also features two ribs 130A and 130B, which radially extend inwards the sidewalls 120A and 120B respectively. Thus, the sidewall 120A connects the bead 130A to the apex 110 while the sidewall 120B connects the bead 130B to the apex 110, the two bead 130A and 130B being opposite each other with respect to the median plane M. Each of the bead 130A and 130B is provided with a bead, respectively 131 A and 131 B, which extends in the corresponding bead along the circumferential direction Z and whose specific features of realization are not limiting as long as these bead 131 A and 131 B allow the tire 100 to be attached to the nominal rim 10, as illustrated schematically in figure 1.
[0052] The top 110, the sidewalls 120A and 120B and the bead 130A and 130B together define a toroidal cavity 140 of the tire 100, delimited by an internal surface 141 of the tire 100. This toroidal cavity 140 allows the tire 100 to be inflated when the latter is mounted on the nominal rim 10. In the mounted state of the tire 100 on this rim, the toroidal cavity 140 is jointly closed by the tire 100 and the rim so as to be able to be pressurized by an inflation gas, which is introduced into the toroidal cavity 140 and with which the internal surface 141 is then in contact. In practice, all or part of the internal surface 141 is advantageously supported by a sealing layer 142 of the tire 100, which is substantially impermeable to the inflation gas and whose composition includes, for example, one or more butyl rubbers, such as that described in WO2016 / 001226.
[0053] The top 110, the sidewalls 120A and 120B and the bead 130A and 130B together delimit an external surface 143 of the tire 100, which is in direct contact with atmospheric air when the tire 100 is mounted on the nominal rim 10.
[0054] The section height H in the sense of the ETRO 2023 standard, as mentioned above, corresponds to the radial distance separating, in meridional section, the outermost radial point of the tire 100, which is carried by the tread 111 and which is here located at the intersection between the median plane M and the outer surface 143, and the innermost radial point of the tire 100, which is carried by one of the two beads 130A and 130B and which is here located on the innermost axial circumferential line of this bead. The nominal section width S in the sense of the ETRO 2023 standard, as mentioned above, corresponds to the axial distance separating, in meridian section, the two outermost axial points of the tire 100 arranged on either side of the median plane M, which belong to the external surface 143 and which are respectively carried here by the sidewalls 120A and 120B.
[0055] As schematically represented in Figure 1, the tire 100 also includes a carcass reinforcement 150 extending from one of the two beads 130A and 130B, respectively in the sidewalls 120A and 120B, to the crown 110. Here, the carcass reinforcement 150 thus extends continuously from one bead 130A to the other. In the crown 110, the carcass reinforcement 150 is arranged radially inside the crown reinforcement 112, more precisely within the working reinforcement 113 of the latter. Here, the carcass reinforcement 150 is arranged radially outside the sealing layer 142.
[0056] The carcass reinforcement 150 comprises, or is made up of, at least one layer of so-called inverted carcass and, in this case, consists of a single layer of inverted carcass 151, which is anchored in each bead 130A, 130B by being inverted around the bead 131A, 131B of the corresponding bead. In other words, for the purpose of its anchoring, the inverted carcass layer 151 wraps around each of the two bead 131A and 131B, from the inside to the outside of the tire 100.The inverted carcass layer 151 thus forms a main part 152 and two inverted sections 153A and 153B: as shown schematically in Figure 1 and as shown in more detail in Figure 2, on which only part of the main part 152 and the inverted section 153A are visible, but not the inverted section 153B, the main part 152 extends from either of the rods 131A and 131B respectively in the flanks 120A and 120B to the top 110, running here continuously from one rod 131A and 131B to the other, while the inverted sections 153A and 153B are arranged axially outside the main part 152 and extend from this main part 152 to two edges 151A and 153B respectively. 151 B of the inverted carcass layer 151, which are axially opposed to each other, being arranged axially on either side of the median plane M.Edge 151 A belongs to the 153A flip and edge 151 B belongs to the 153B flip.
[0057] In practice, the edge 151 A is arranged in the bead 130A and / or the side 120A, being embedded in the mass of materials constituting this bead 130A and / or this side 120A, while the edge 151 B is arranged in the bead 130B and / or the side 120B, being embedded in the mass of materials constituting this bead 130B and / or this side 120B: here, the edges 151 A and 151 B of the inverted carcass layer 151 are thus arranged respectively in the side 120A and in the side 120B; in an unrepresented variant, it is otherwise.
[0058] In all cases, according to an advantageous arrangement which is illustrated in figures 1 to 4, each of the edges 151 A and 151 B of the inverted carcass layer 151 is axially separated from the external surface 143 of the tire 100 exclusively by an elastomeric mass of the tire 100: here, as clearly visible in figure 2, the elastomeric mass of the tire 100, which axially separates the edge 151 A from the external surface 143, is formed of a cluster of two elastomeric layers which, axially facing the edge 151 A, are superimposed one on the other along the axial direction Y, namely a sidewall elastomeric layer 160A and a protective elastomeric layer 161 A. The sidewall elastomeric layer 160A constitutes an external portion of the sidewall 120A and carries a corresponding part of the external surface 153.The protective elastomeric layer 161 A constitutes a portion of the bead 130A, by which the latter is brought into contact with the nominal rim 10 when the tire 100 is mounted on this nominal rim, and extends radially outwards into the sidewall 120A, so that this protective elastomeric layer 161 A surrounds both the whole of the reversal 153A, being arranged on the axially outer side of this reversal 153A, and a most radially inner portion of the main part 152, being arranged on the axially inner side of this most radially inner portion of the main part 152.Although not shown in detail in Figure 1, the elastomeric mass of the tire 100, which axially separates the edge 151 B from the external surface 143, is formed of a cluster of two elastomeric layers, which are respectively similar to the sidewall elastomeric layer 160A and the protective elastomeric layer 161 A and which are respectively symmetrical to the latter with respect to the median plane M. Insofar as the aforementioned elastomeric masses and the aforementioned elastomeric layers are "elastomeric" in the sense defined in the introductory part of this document, it is understood that these masses and layers are devoid of reinforcement, in particular wire reinforcement. Thus, the carcass reinforcement 150 is notably devoid of a so-called "embedded" carcass layer, that is to say, one which would be axially external to each of the edges 151 A and 151 B of the inverted carcass layer 151.
[0059] Also, according to an advantageous arrangement illustrated in Figures 1 to 4, each of the edges 151A and 151B of the inverted carcass layer 151 is axially separated from the main part 152 by an elastomeric layer of the tire 100, called the packing layer: as clearly visible in Figure 2, the edge 151A is axially separated from the main part 152 by an elastomeric packing layer 162A, which extends radially outwards from the bead 131A, axially separating the entire inverted section 153A from the main part 152. Here, the elastomeric packing layer 162A thus extends radially into the bead 130A as far as the sidewall 120A, where this elastomeric packing layer 162A runs alongside the protective elastomeric layer 161A. until it reaches the 160A flank elastomeric layer.
[0060] The inverted carcass layer 151 includes wire reinforcements which are visible in figures 3 and 4 where these wire reinforcements are referenced 151 R. These wire reinforcements 151 R are embedded in an elastomeric coating matrix 151 M of the inverted carcass layer 151 and extend lengthwise from one edge to the other 151 A and 151 B in a principal direction which, at least in the principal part 152, forms with the circumferential direction Z an angle which, in absolute value, is greater than or equal to 60°, preferably from 80° to 90°, and this at least in all or part of the flanks 120A and 120B.In embodiments enabling the performance of so-called radial tires as defined by ETRTO, each wire reinforcement 151 R of the carcass layer 151 extends lengthwise, at least in the main part 152, along a principal direction forming an angle with the circumferential direction Z of 80° to 90° in absolute value. Alternatively, this angle is variable, ranging from 80° to 90° in at least a portion of each of the two sidewalls 120A and 120B and being strictly less than 80° in at least a portion of the crown 110.
[0061] In all cases, 151 R wire reinforcements are textile wire reinforcements. By textile, we mean that each 151 R wire reinforcement consists of a textile monofilament, i.e., a non-metallic one, or, preferably, an assembly of textile monofilaments, i.e., non-metallic ones. This textile monofilament or these monofilaments are advantageously made of polyester, particularly polyethylene terephthalate, or aliphatic polyamide, particularly nylon, or aromatic polyamide, particularly aramid, or rayon, or a combination of at least two of these textile materials. For various reasons, including practical and economic ones, this textile monofilament or these monofilaments are preferably made of polyethylene terephthalate.
[0062] Regardless of the textile material constituting the 151 R wire reinforcements, each of these 151 R wire reinforcements advantageously has a diameter ranging from 0.4 mm to 1.0 mm. This dimensioning reconciles good performance in terms of, among other things, reinforcement and size. In all cases, on each of its edges 151 A and 151 B, the inverted carcass layer 151 delimits an end slice which, by definition, forms a terminal surface of the inverted carcass layer 151, at which the inverted carcass layer 151 is interrupted radially outwards, and which axially connects the two opposite principal faces of the inverted carcass layer 151. The end slice of edge 151 A is clearly visible in Figures 2 and 3 where it is referenced as 154A, while the end slice of edge 151 B is not visible in the figures in as much detail as the end slice 154A of edge 151 A.Subsequently, we will describe in more detail the end slice 154A of the edge 151 A, it being understood that the end slice of the edge 151 B has arrangements which are similar to those of the end slice 154A and which are deduced in particular by symmetry with respect to the median plane M.
[0063] As shown in Figure 2, the end edge 154A of the edge 151A of the inverted carcass layer 151 is located at a radial distance H154A from the innermost radial point of the bead 131A. This radial distance H154A is advantageously between 0.1*H and 0.95*H, preferably between 0.1*H and 0.4*H. In practice, this radial distance H154A quantifies the radial dimension of the inverted 153A. When the radial distance H154A is less than 0.1*H, the anchoring of the inverted carcass layer 151 in the bead 130A may be insufficient. When the radial distance H154A is greater than 0.95*H, or even 0.4*H, the tire 100 becomes heavier.
[0064] In all cases, as can be clearly seen in figures 2 to 4, the end edge 154A of the edge 151 A of the inverted carcass layer 151 is wrapped, here over the entire circumference of the tire 100, by at least one elastomeric layer of the tire 100: here, the end edge 154A is thus wrapped jointly by the protective elastomeric layer 161 A and by the elastomeric filling layer 162A; in variants not shown, only one or the other of these protective elastomeric layers 161 A and filling layer 162A wraps the end edge 154A.
[0065] Furthermore, on the end edge 154A of the edge 151A of the inverted carcass layer 151, the elastomeric coating matrix 151M of the inverted carcass layer 151 forms an end end 151MA, and the wire reinforcements 151R are transversely interrupted so that, as clearly visible in Figures 3 and 4, each of these wire reinforcements 151R forms an end section 151RA. The end edge 154A is thus formed by the respective end sections 151RA of the wire reinforcements 151R and the end end 151MA of the elastomeric coating matrix 151M, which separates the respective end sections 151RA of the wire reinforcements 151R from one another.Each of the respective end sections 151 RA of the wire reinforcements 151 R of the inverted carcass layer 151 is exposed vis-à-vis the rest of the inverted carcass layer 151, in the sense that each of these respective end sections 151 RA is not covered by a constituent of the inverted carcass layer 151, in particular by the elastomeric coating matrix 151 M of the latter.
[0066] To prevent the textile monofilament(s) constituting each wire reinforcement 151R from separating from each other and from the elastomeric coating matrix 151M at the end edge 154A of the edge 151A of the inverted carcass layer 151, the tire 100 includes an adhesive interlayer 170A which is interposed between the end edge 154A of the edge 151A and the protective elastomeric layers 161A and the padding 162A that envelop this end edge 154A. As clearly visible in Figures 2 to 4, this adhesive interlayer 170A thus directly covers all or part of the end edge 154A so as to bond the respective end sections 151RA of the wire reinforcements 151R.The adhesive forming the adhesive interlayer 170A is thus applied to the end edge 154A of the edge 151 A and coats each of the respective end sections 151 RA of the wire reinforcements 151 R, where necessary by locally penetrating between the elastomeric coating matrix 151M and the textile monofilament(s) constituting each wire reinforcement 151 R, as well as between the latter. This makes it possible to prevent or significantly delay the initiation of decohesion of this or these textile monofilaments from each other and from the elastomeric coating matrix 151M on the end edge 154A of the edge 151 A.
[0067] In practice, the adhesive interlayer 170A consists of a mass of adhesive material, which is thin in the radial direction X and which is applied directly between the end edge 154A of the rim 151 A and the surrounding elastomeric layer(s) of the tire 100, here the protective elastomeric layer 161 A and the filling elastomeric layer 162A. The form, in particular solid or viscous liquid or fluid liquid, in which this adhesive material is integrated into the tire 100 during its manufacture is irrelevant, as long as, at the end of this manufacture, this adhesive material forms a mass or a film, which is interposed between the end edge 154A of the rim 151 A and the elastomeric layer(s) enveloping this end edge 154A, by gluing the end sections 151 RA of the wire reinforcements 151 R.
[0068] Of course, an adhesive interlayer 170B, which is schematically visible only in figure 1 and which is similar to the adhesive interlayer 170A, is interposed between the end slice of the edge 151 B and the elastomeric layer(s) enveloping this end slice of the edge 151 B, by gluing the end sections formed respectively by the wire reinforcements 151 R on this end slice of the edge 151 B.
[0069] In practical, efficient, and economical forms, each of the 170A and 170B adhesive interleaves is advantageously made of a latex-based adhesive, in particular a so-called "RFL" adhesive, i.e., resorcinol-formaldehyde latex, or a cyanoacrylate adhesive. In practice, other adhesive formulations are possible.
[0070] With reference to figures 5 to 9, we will now describe a manufacturing process for manufacturing tire 100.
[0071] To implement this manufacturing process, a master tape 20, otherwise called a "straight grain web" in the field, is initially available, shown schematically in Figure 5. The master tape 20 comprises an uncrosslinked elastomeric coating matrix 21, which is intended to form the elastomeric coating matrix 151M once crosslinked, and textile wire reinforcements 22, which are embedded in the elastomeric coating matrix 21 and which are intended to form the wire reinforcements 151R. Within the master tape 20, the textile wire reinforcements 22 extend lengthwise parallel to each other and parallel to two opposite edges 20A and 20B of the master tape 20.In practice, the master tape 20 is made available by being wound on itself in the form of a reel centered on an axis 20C around which the edges 20A and 20B are wound circumferentially: by means of at least partial unwinding of this reel, a terminal portion of the master tape 20 is made available flat.
[0072] In the first stage of the manufacturing process, schematically illustrated in Figure 5, a layer of carcass 30 is cut from the aforementioned terminal portion of the master strip 20 to form the inverted carcass layer 151. This cutting of the master strip 20, indicated by long dashed lines in Figure 5, creates two selvedges 30A and 30B of the carcass layer 30, delimiting the latter. The textile thread reinforcements 22 extend lengthwise between these selvedges, here substantially perpendicular to the selvedges 30A and 30B. These selvedges 30A and 30B of the carcass layer 30 are intended to form the two edges 151A and 151B of the inverted carcass layer 151, respectively.During this cutting of the master strip 20, each of the textile wire reinforcements 22 is cut along a direction transverse to the longitudinal direction of the wire reinforcement 22 at each selvage 30A, 30B of the carcass layer 30 and forms a section which is thus exposed vis-à-vis the rest of the carcass layer 30.
[0073] In practice, in the first step mentioned above and as schematically illustrated in Figure 5, the carcass sheet 30 is made up of several sections, which are successively cut from the master strip 20 as explained above, then joined end-to-end and welded together. The carcass sheet 30 is then advantageously wound onto itself in the form of a coil centered around an axis 30C around which the selvedges 30A and 30B are wound circumferentially.
[0074] In a second step of the manufacturing process, schematically illustrated in Figure 6, the carcass ply 30 is wound around a cylindrical support 40 centered on an axis 40C, such that the selvedges 30A and 30B of the carcass ply extend circumferentially around the axis 40C of the cylindrical support 40. The cylindrical support 40 is a well-known manufacturing tool in the field and will therefore not be described further, it being simply noted that its axis 40C extends in a direction intended to form the axial Y direction of the tire 100. In practice, the cylindrical support 40 is advantageously rotatable around its axis 40C so that the carcass ply 30 can be progressively wound around the cylindrical support 40 in one revolution, before the carcass ply 30 is cut parallel to each other along its selvedges 30A and 30B. to the wire reinforcements 22, for example by a cutting tool 41.
[0075] Here, in the second step mentioned above and as schematically illustrated in figure 5, the carcass sheet 30 is, before being wound around the cylindrical support 40, made available flat by first unwinding at least part of the coil formed by this carcass sheet 30 at the end of the first step mentioned above, then the formation of at least one decoupling undulation by the carcass sheet 30, then the flattening of the carcass sheet 30 on a conveyor table 42.
[0076] Similarly, according to an advantageous arrangement of the second step mentioned above, which is not illustrated in the figures, before the carcass sheet 30 is wound around the cylindrical support 40, a sealing sheet intended to form the sealing layer 142 is wound around the latter. In a third step of the manufacturing process, illustrated schematically in figure 7, the rods 131 A and 131 B are each attached around the carcass sheet 30 held supported by the cylindrical support 40. The rods 131 A and 131 B are thus attached axially between the two edges 30A and 30B of the carcass sheet 30.
[0077] In a fourth step of the manufacturing process, schematically illustrated in Figure 8, a portion 31A of the carcass layer 30, which includes the selvedge 30A, is folded around the rod 131A, and a portion 31B of the carcass layer 30, which includes the selvedge 30B, is folded around the rod 131B, while the cylindrical support 40 continues to carry the rods 131A and 131B and the remainder of the carcass layer 30, as in the third step. The two folded portions 31A and 31B of the carcass layer 30 are intended to form, respectively, the two inversions 153A and 153B of the inverted carcass layer 151.
[0078] In practice, during the aforementioned fourth step, two non-crosslinked elastomeric strips, not shown in the figures and intended to form, once crosslinked, respectively the two elastomeric stuffing layers respectively associated with the rods 131 A and 131 B, such as the elastomeric stuffing layer 162A, are brought respectively around the rods 131A and 131 B before the parts 31 A and 31 B of the carcass sheet 30 are folded down. In a fifth step of the manufacturing process, schematically illustrated in Figure 9, the selvedge 30A of the carcass ply 30 is wrapped by non-crosslinked elastomeric strips 50A and 51A, which are arranged at least around the folded part 31A of the carcass ply 30 and which are intended to form, once crosslinked, respectively the protective elastomeric layer 161A and the sidewall elastomeric layer 160A of the tire 100.Similarly, the edge 30B of the carcass ply 30 is wrapped by non-crosslinked elastomeric strips 50B and 51B, which are arranged at least around the folded part 31B of the carcass ply 30 and which are intended to form, once crosslinked, respectively the protective elastomeric layer and the sidewall elastomeric layer of the tire 100, associated with the edge 151B of the carcass layer 151.
[0079] In a sixth step of the manufacturing process, not illustrated in the figures and usually called the shaping step in the field, the assembly comprising the carcass sheet 30 and the elastomeric strips 50A, 51A, 50B and 51B is deformed so as to change this assembly from a substantially cylindrical shape around the axis 40C, which this assembly has at the end of the aforementioned fifth step, to a substantially toric shape around the axis 40C.
[0080] The assembly, substantially toroidal in shape around the 40C axis, obtained at the end of the aforementioned sixth step, forms part of a raw blank for the 100 tire, in the sense that this assembly contains crosslinkable compositions in their uncrosslinked state. This raw blank is then placed in a curing mold to mold the raw blank and crosslink the crosslinkable compositions. During this molding of the raw blank, it is expanded radially and circumferentially, for example by pressurizing a deformable membrane, so as to press the raw blank against surfaces of the curing mold.
[0081] In practice, the first step mentioned above can be carried out separately from the other steps mentioned above in the manufacturing process, typically during a preparation phase. The second, third, fourth, and fifth steps are carried out successively during the same phase of the manufacturing process, which can be described as the production phase.
[0082] In all cases, after cutting the carcass layer 30 from the parent strip 20 in the first step and before wrapping the selvedges 30A and 30B of the carcass layer 30 with the elastomeric strips 50A, 51A, 50B and 51B in the fifth step, at least the respective sections of the textile thread reinforcements 22 at each of the selvedges 30A and 30B of the carcass layer 30 are covered with a sizing agent 60 intended to form the adhesive interlayers 170A and 170B. The sizing agent 60 thus consists of the adhesive for the adhesive interlayers 170A and 170B. This 60 sizing agent is applied to the 30A and 30B selvedges by any appropriate means, as schematically indicated by wavy arrows in figures 5 to 8.
[0083] Multiple possibilities exist regarding the moment(s) when the sizing agent 60 is applied to the edges 30A and 30B:
[0084] - as illustrated in Figure 5, the sizing agent 60 is applied during the aforementioned first step, after the carcass sheet 30 has been cut from the master strip 20 and before the carcass sheet 30 is wound onto itself in the form of the reel centered around the axis 30C; and / or
[0085] - as illustrated in Figure 6, the gluing agent 60 is applicable during the second step mentioned above, in particular during the formation of the decoupling corrugation(s) and / or during the flattening of the carcass sheet 30 on the conveyor table 42 and / or during the winding of the carcass sheet 30 around the cylindrical support 40; and / or
[0086] - the gluing agent 60 is applicable to the selvedges 30A and 30B after the carcass sheet 30 has been wrapped around the cylindrical support 40, and before the parts 31 A and 31 B of the carcass sheet 30 have been folded down, as illustrated in figure 7, and / or after these parts 31 A and 31 B have been folded down, as illustrated in figure 8.
[0087] In practice, the moment(s) when the sizing agent 60 is thus applied to the edges 30A and 30B are chosen, among other things, to minimize the consequences of the corresponding application operations on the rest of the manufacturing process and / or to take into account the specificities of the glue constituting the sizing agent 60.
[0088] Figure 10 shows a variant of tire 100, referenced as 200. Tire 200 is similar, if not identical, to tire 100, except that its carcass reinforcement 250, which is functionally similar to carcass reinforcement 150, comprises both:
[0089] - a layer of inverted carcass 251, which is similar to the layer of inverted carcass 151 and which thus includes a main part 252, similar to the main part 152, and two inverted parts 253A and 253B, respectively similar to the inverted parts 153A and 153B, and
[0090] - another layer of carcass 255, described as non-reversed in the sense that this layer of carcass 255 does not wrap around beads 231 A and 231 B of the tire 200, respectively similar to beads 131 A and 131 B.
[0091] The unturned carcass layer 255 is thus totally arranged radially outside the rods 231 A and 231 B and axially inside the turns 253A and 253B of the turned carcass layer 251. More precisely, the unturned carcass layer 255 is interposed on the one hand axially between the turn 253A and the main part 252 of the turned carcass layer 251 and on the other hand axially between the turn 253B and the main part 252 of the turned carcass layer 251.
[0092] Figure 11 shows a variant of tire 100, referenced as 300. Tire 300 is similar, if not identical, to tire 100, except that its carcass reinforcement 350, which is functionally similar to carcass reinforcement 150, comprises both:
[0093] - a layer of inverted carcass 351, which is similar to the layer of inverted carcass 151 and which thus includes a main part 352, similar to the main part 152, and two inverted parts 353A and 353B, respectively similar to the inverted parts 153A and 153B, and
[0094] - another layer of carcass 356, described as non-reversed in the sense that this layer of carcass 356 does not wrap around the beads 331 A and 331 B of the tire 300, respectively similar to the beads 131 A and 131 B.
[0095] The unreversed carcass layer 356 is thus fully arranged radially outside the rods 331 A and 331 B and axially inside the reversals 353A and 353B of the reversed carcass layer 351. More precisely, the unreversed carcass layer 356 is arranged radially inside the main part 352 of the reversed carcass layer 351.
[0096] Thus, multiple forms of realization of the tire carcass reinforcement, such as carcass reinforcements 150, 250 and 350, are compatible with adhesive interlayers such as adhesive interlayers 170A and 170B, such adhesive interlayers being referenced 270A and 270B on figure 10 for the 200 tire and being referenced 370A and 370B on figure 11 for the 300 tire.
[0097] In practice, tires 200 and 300 can be manufactured by a process similar to that described opposite figures 5 to 9, subject to adjustments to this process to take into account the unturned carcass layers 255 and 356.
[0098] The invention is not limited to the embodiments described above. In particular, new embodiments can be derived by combining all or part of each of the embodiments described so far with all or part of the other embodiments.
Claims
23 Demands 1. Pneumatic (100; 200; 300), comprising: - a summit (110), - two flanks (120A, 120B) which each extend radially inwards from the apex, - two ridges (130A, 130B), which extend radially inwards along the two sidewalls respectively and which each include a bead (131 A, 131 B; 231 A, 231 B; 331 A, 331 B) intended to allow the tire to be attached to a rim (10), and - a carcass frame (150; 250; 350), which extends from either of the ridges respectively in the flanks to the top, in which the carcass frame (150; 250; 350) comprises a so-called inverted carcass layer (151; 251; 351), which: - is anchored in each bead (130A, 130B) by being turned around the rod (131 A, 131 B ; 231 A, 231 B ; 331 A, 331 B) of the corresponding bead so that the turned-over carcass layer forms: - a main part (152; 252; 352) which extends from either of the rods respectively in the flanks (120A, 120B) to the top (110), and - two inversions (153A, 153B; 253A, 253B; 353A, 353B), which are arranged axially outside the main part and which extend from the main part to respectively two edges (151 A, 151 B) of the inverted carcass layer, axially opposed to each other and respectively arranged in the ridges and / or sides, - delimits, on each of its edges, an end slice (154A) which is enveloped by at least one elastomeric layer (161 A, 162A) of the tire (100; 200; 300), and - includes textile wire reinforcements (151 R) which: - extend lengthwise from one edge (151 A, 151 B) to the other of the layer of inverted carcass, and - are, on the end edge (154A) of each edge of the inverted carcass layer, transversely interrupted to form respective end sections (151 RA) of the textile thread reinforcements, which are exposed vis-à-vis the rest of the inverted carcass layer, characterized in that the tire (100; 200; 300) further comprises, for each edge (151 A, 151 B) of the inverted carcass layer (151; 251; 351), an adhesive interlayer (170A, 170B; 270A, 270B; 370A, 370B) which is interposed between the end edge (154A) of the edge of the inverted carcass layer and said at least one corresponding elastomeric layer (161 A, 162A), by gluing the respective sections (151 RA) textile wire reinforcements (151 R).
2. Pneumatic according to claim 1, wherein each adhesive interlayer (170A, 170B; 270A, 270B; 370A, 370B) is made of a latex adhesive, in particular resorcinol-formaldehyde latex, or a cyanoacrylate adhesive.
3. Pneumatic according to any one of the preceding claims, wherein each textile wire reinforcement (151 R) is made of one or more monofilaments of polyester, in particular polyethylene terephthalate, and / or aliphatic polyamide, in particular nylon, and / or aromatic polyamide, in particular aramid, and / or rayon.
4. Pneumatic according to any one of the preceding claims, wherein each textile wire reinforcement (151 R) has a diameter ranging from 0.4 mm to 1.0 mm.
5. Tire according to any one of the preceding claims, wherein the end slice (154A) of each of the edges (151 A, 151 B) of the inverted carcass layer (151; 251; 351) is located at a radial distance (H154A) from the radially innermost point of the corresponding bead (131 A, 131 B; 231 A, 231 B; 331 A, 331 B), this radial distance being between 0.1*H and 0.95*H, preferably between 0.1*H and 0.4*H, where H is the section height of the tire (100; 200; 300) as defined in ETRTO 2023.
6. A tire according to any one of the preceding claims, wherein each of the edges (151 A, 151 B) of the inverted carcass layer (151; 251; 351) is axially separated from an external face (143) of the tire (100; 200; 300) exclusively by an elastomeric mass (160A, 161 A) of the tire.
7. A tire according to any one of the preceding claims, wherein the carcass reinforcement (150) is constituted by the inverted carcass layer (151).
8. Pneumatic according to any one of claims 1 to 6, wherein the carcass reinforcement (250; 350) further comprises a so-called non-reversed carcass layer (255; 356), which is totally arranged radially outside the beads (231 A, 231 B; 331 A, 331 B) and axially inside the reversals (253A, 253B; 353A, 353B).
9. Tire according to any one of the preceding claims, wherein a ratio, expressed as a percentage, between the section height (H) and the nominal section width (S) of the tire (100; 200; 300) as defined in ETRTO 2023 is at most equal to 90 and is at least equal to 20, and wherein the nominal section width (S) is at least equal to 115 mm and at most equal to 385 mm.
10. A method for manufacturing a tire (100; 200; 300) according to any one of the preceding claims, wherein: - in a parent strip (20) comprising textile wire reinforcements (22) intended to form the textile wire reinforcements (151 R) of the inverted carcass layer (151; 251; 351), a sheet of carcass (30) intended to form the inverted carcass layer (151; 251; 351) is cut so as to delimit the sheet of carcass (30) by two selvedges (30A, 30B), which are intended to form respectively the two edges (151 A, 151 B) of the inverted carcass layer and at each of which the textile wire reinforcements (22) of the parent strip (20) are cut transversely, forming respective sections of the textile wire reinforcements of the parent strip, which are exposed vis-à-vis the rest of the sheet of carcass, then - around a cylindrical support (40) centered on an axis (40C), the carcass sheet (30) is wound so that the edges (30A, 30B) of the carcass sheet extend circumferentially around the axis (40C), then - while the cylindrical support (40) carries the frame layer (30), the rods (131 A, 131 B; 231 A, 231 B; 331 A, 331 B) are brought axially around the frame layer between the two edges (30A, 30B) of the frame layer, then - while the cylindrical support (40) carries the carcass layer (30) and the rods (131 A, 131 B; 231 A, 231 B; 331 A, 331 B), a portion (31 A, 31 B) of the carcass layer is folded around each rod, the two folded portions of the carcass layer including respectively the two edges (30A, 30B) of the carcass layer and being intended to form respectively the two folds (153A, 153B; 253A, 253B; 353A, 353B) of the folded carcass layer (151; 251; 351), then - each selvedge (30A, 30B) of the carcass ply (30) is wrapped by at least one elastomeric strip (50A, 50B), arranged around the corresponding folded portion (31A, 31B) of the carcass ply and intended to form at least partially said at least one corresponding elastomeric layer (161A, 162A), and wherein, after cutting the carcass ply (30) from the parent strip (20) and before wrapping the selvedges (30A, 30B) of the carcass ply with the elastomeric strips (50A, 50B), at least the respective sections of the textile thread reinforcements (22) of the parent strip (20) are covered at each selvedge of the carcass ply with a sizing agent (60) intended to form each adhesive interlayer (170A, 170B; 270A, 270B; 370A, 370B).