TIRE HAVING IMPROVED UNIFORMITY AND METHOD FOR MANUFACTURING SAME

Abstract

A method for manufacturing a tire comprising a carcass reinforcement comprising a carcass layer and a working reinforcement comprising a single working layer comprising forming, around a support, a wound carcass assembly (52) intended to form the carcass layer and a wound working assembly intended to form the working layer, and then deforming the support. The wound carcass assembly (52) is formed so as to form either a junction (56) by abutment without forming a superposition, or a junction (56) by overlapping, or without forming a junction.

Claims

1.-15. (canceled)

16. A method for manufacturing a tire (10) comprising a crown (12), two sidewalls (22) and two beads (24), each sidewall (22) connecting each bead (24) to the crown (12), a carcass reinforcement (32) anchored in each bead (24) and extending in each sidewall (22) and radially internally at the crown (12), the carcass reinforcement (32) comprising at least one carcass layer (34), and the crown (12) comprising a tread (20) intended to come into contact with the ground when the tire (10) is rolling and a crown reinforcement (14) arranged radially between the tread (20) and the carcass reinforcement (32), the crown reinforcement (14) comprising a working reinforcement (16) comprising a single working layer (18), the method comprising: winding a carcass ply (51) or a plurality of carcass plies (51) around a support (60) having a substantially cylindrical shape around a main axis (A), to form at least one wound carcass assembly (52) intended to form the carcass layer (34), the wound carcass assembly (52) being axially delimited by two axial edges (52A, 52B) of the wound carcass assembly (52) and comprising carcass filamentary reinforcing elements (340) extending substantially parallel to one another axially from one axial edge (52A, 52B) to the other axial edge (52A, 52B) of the wound carcass assembly (52), each carcass filamentary reinforcing element (340) extending, in the or each carcass ply (51), in a main direction (K3) of each carcass filamentary reinforcing element (340), the main direction (K3) of each carcass filamentary reinforcing element (340) in the or each carcass ply (51) forming, with the circumferential direction (Z) of the support (60), an initial angle (A3) of each carcass filamentary reinforcing element (340); winding a working ply (49) or a plurality of working plies (50), radially outside the wound carcass assembly (52), to form a wound working assembly (50) intended to form the working layer (18), the wound working assembly (50) being axially delimited by two axial edges (50A, 50B) of the wound working assembly (50) and comprising working filamentary reinforcing elements (180) extending substantially parallel to one another axially from one axial edge (50A, 50B) to the other axial edge (50A, 50B) of the wound working assembly (50), each working filamentary reinforcing element (180) extending, in the or each working ply (49), in a main direction (K2) of each working filamentary reinforcing element (180) in the or each working ply (49), the main direction (K2) of each working filamentary reinforcing element (180) in the or each working ply (49) forming, with the circumferential direction (Z) of the support (60), an initial angle (A2) of each working filamentary reinforcing element (180), the wound carcass assembly (52) and the wound working assembly (50) forming an assembly (58) of substantially cylindrical shape around the main axis (A) of the support (60); and deforming the assembly (58) of substantially cylindrical shape around the main axis (A) of the support (60) so as to obtain an assembly (58) of substantially toric shape around the main axis (A) of the support (60) so that: the main direction (K3) of each carcass filamentary reinforcing element (340) forms, with the circumferential direction (z) of the support (60): a final angle (B3 S) of each carcass filamentary reinforcing element (340), in absolute value, strictly less than 80°, in a portion (52S) of the wound carcass assembly (52) extending axially in radial line with the wound working assembly (50), and a final angle (B3F) of each carcass filamentary reinforcing element (340) ranging, in absolute value, from 80° to 90°, in a portion (52F) of the wound carcass assembly (52) intended to extend radially in each sidewall (22), and the main direction (K2) of each working filamentary reinforcing element (180) forms, with the circumferential direction (z) of the support (60), a final angle (B2) of each working filamentary reinforcing element (180), in absolute value, strictly greater than 10°, wherein, during the step of forming the wound carcass assembly (52), the wound carcass assembly (52) having two circumferential end edges (54A, 54B) extending axially from one of the axial edges (52A, 52B) to the other of the axial edges (52A, 52B) of the wound carcass assembly (52), one of the following alternatives I, II, III is implemented: I—the wound carcass assembly (52) is formed so as to form a junction (56) between the two circumferential end edges (54A, 54B) of the wound carcass assembly (52) by abutment without forming a superposition between a carcass filamentary reinforcing element (340) of one of the circumferential end edges (54A, 54B) of the wound carcass assembly (52) and a carcass filamentary reinforcing element (340) of the other of the circumferential end edges (54A, 54B) of the wound carcass assembly (52), at least in a portion (52S) of the wound carcass assembly (52) intended to extend axially in radial line with the wound working assembly (50), II—the wound carcass assembly (52) is formed so as to form a junction (56) between the two circumferential end edges (54A, 54B) of the wound carcass assembly by overlapping so as to form a radial superposition between at least one carcass filamentary reinforcing element (340) of one of the circumferential end edges (54A, 54B) of the wound carcass assembly and at least one carcass filamentary reinforcing element (340) of the other of the circumferential end edges (54A, 54B) of the wound carcass assembly, at least in the portion (52S) of the wound carcass assembly (52) intended to extend axially in radial line with the wound working assembly (50), so that, without a step of forming the wound working assembly (50) prior to the deformation step, the deformation step would lead to an opening of the junction (56), and III—the wound carcass assembly (52) is formed so that the two circumferential end edges (54A, 54B) of the wound carcass assembly are circumferentially spaced from one another at least in the portion (52S) of the wound carcass assembly (52) intended to extend axially in radial line with the wound working assembly (50).

17. The method according to claim 16, wherein, during the step of forming the wound carcass assembly (52), one of the alternatives I or II is implemented.

18. The method according to claim 17, wherein, during the step of forming the wound carcass assembly (52), the alternative I is implemented.

19. The method according to claim 16, wherein, subsequent to the step of deforming the assembly (58), there is arranged, radially outside the assembly (58) of substantially toric shape, a wound hooping assembly intended to form a hoop reinforcement (17), the wound hooping assembly being formed by helical winding of at least one hooping filamentary reinforcing element (170) or of a hooping ply obtained by embedding one or more hooping filamentary reinforcing elements (170) in an elastomeric matrix, so as to extend axially from one axial edge to the other axial edge of the wound hooping assembly.

20. The method according to claim 16, wherein the initial angle (A2) formed by the main direction (K2) of each working filamentary reinforcing element (180) with the circumferential direction (z) of the support (60) is, in absolute value, strictly greater than 0°.

21. The method according to claim 16, wherein the initial angle (A3) formed by the main direction (K3) of each carcass filamentary reinforcing element (340) with the circumferential direction (z) of the support (60) is, in absolute value, strictly greater than 0°.

22. The method according to claim 16, wherein the final angle (B2) formed by the main direction (K2) of each working filamentary reinforcing element (180) with the circumferential direction (z) of the support (60) ranges, in absolute value, from 15° to 50°.

23. The method according to claim 16, wherein the final angle (B3S) formed by the main direction (K3) of each carcass filamentary reinforcing element (340) with the circumferential direction (z) of the support (60) is, in absolute value, greater than or equal to 10° in the portion (52S) of the wound carcass assembly (52) extending axially in radial line with the wound working assembly (50).

24. A tire obtained by the method according to claim 16.

25. The tire (10) according to claim 24, wherein the working layer (18) is axially delimited by two axial edges (18A, 18B) of the working layer (18) and comprises the working filamentary reinforcing elements (180) extending axially from one axial edge (18A, 18B) to the other axial edge (18A, 18B) of the working layer (18) substantially parallel to one another in a main direction (D2) of each working filamentary reinforcing element (180) forming, with the circumferential direction (Z) of the tire (10), an angle (AT), in absolute value, strictly greater than 10°, and wherein the carcass layer (34) is axially delimited by two axial edges (34A, 34B) of the carcass layer (34) and comprises the carcass filamentary reinforcing elements (340) extending axially from one axial edge (34A, 34B) to the other axial edge (34A, 34B) of the carcass layer (34), each carcass filamentary reinforcing element (340) extending in a main direction (D3) of each carcass filamentary reinforcing element (340) forming, with the circumferential direction (Z) of the tire (10): an angle (ACS), in absolute value, strictly less than 80° in a portion (34S) of the carcass layer (34) extending axially in radial line with the working layer (18), and an angle (ACF), in absolute value, ranging from 80° to 90° in at least one portion (34F) of the carcass layer (34) extending radially in each sidewall (22).

26. The tire according to claim 24, wherein the crown reinforcement (14) comprises a hoop reinforcement (17) arranged radially outside the working reinforcement (16), the hoop reinforcement (17) being axially delimited by two axial edges (17A, 17B) of the hoop reinforcement (17) and comprising at least one hooping filamentary reinforcing element (170) wound circumferentially helically so as to extend axially from one axial edge (17A, 17B) to the other axial edge (17A, 17B) of the hoop reinforcement (17) in a main direction (D1) of the or each hooping filamentary reinforcing element (170).

27. The tire according to claim 26, wherein the main direction (D1) of the or each hooping filamentary reinforcing element (170), the main direction (D2) of each working filamentary reinforcing element (180) and the main direction (D3) of each carcass filamentary reinforcing element (340) form, with the circumferential direction (Z) of the tire (10), in a portion (PS′) of the tire (10) lying axially between the axial edges of the axially narrowest layer or reinforcement among the working layer (18) and the hoop reinforcement (17), paired angles (D1, D2, D3) different in absolute value.

28. The tire (10) according to claim 24, wherein the main direction (D2) of each working filamentary reinforcing element (180) and the main direction (D3) of each carcass filamentary reinforcing element (340) form, with the circumferential direction (Z) of the tire (10), in a portion (PS) of the tire (10) lying axially between the axial edges (18A, 18B) of the working layer (18), angles (D2, D3) of opposite orientations.

29. The tire (10) according to claim 24, wherein the main direction (D2) of each working filamentary reinforcing element (180) forms, with the circumferential direction (Z) of the tire (10), an angle (AT) ranging, in absolute value, from 15° to 50°.

30. The tire according to claim 24, wherein the main direction (D3) of each carcass filamentary reinforcing element (340) forms, with the circumferential direction (Z) of the tire (10), an angle (ACS), in absolute value, greater than or equal to 10°, in the portion (34S) of the carcass layer (34) extending axially in radial line with the working layer (18).

Description

[0154] The invention as well as its advantages will be easily understood in the light of the detailed description and of the nonlimiting exemplary embodiments which follow, as well as of FIGS. 1 to 19 relating to these examples in which:

[0155] FIG. 1 is a view in section in a meridian section plane of a tyre according to the invention;

[0156] FIG. 2 is a schematic cutaway view of the tyre of FIG. 1 illustrating the arrangement of the filamentary reinforcing elements in radial line with and radially overhanging the working layer;

[0157] FIG. 3 is a schematic view of the carcass filamentary reinforcing elements arranged in the sidewall of the tyre of FIG. 1;

[0158] FIG. 4 is a view in a section plane perpendicular to the axial direction of a portion of the crown of the tyre of FIG. 1;

[0159] FIGS. 5 to 13 illustrate the different steps of a method according to a first embodiment of the invention making it possible to manufacture the tyre of FIG. 1;

[0160] FIGS. 14 to 16 illustrate steps of a method according to a second embodiment of the invention similar to those illustrated by FIGS. 4 to 6; and

[0161] FIGS. 17 to 19 illustrate steps of a method according to a third embodiment of the invention similar to those illustrated by FIGS. 4 to 6.

[0162] In the figures relating to the tyre, there is shown a reference frame X, Y, Z corresponding to the usual axial (X), radial (Y) and circumferential (Z) directions, respectively, of a tyre. In the figures relating to the method, there is shown a reference frame x, y, z corresponding to the usual axial (x), radial (y) and circumferential (z) directions, respectively, of a manufacturing support deformable between a substantially cylindrical shape and a toric shape around the x axis.

[0163] FIG. 1 shows a tyre according to the invention and denoted by the general reference 10. The tyre 10 is substantially of revolution about an axis substantially parallel to the axial direction X. The tyre 10 is here intended for a passenger vehicle and has dimensions 245/45R18.

[0164] The tyre 10 comprises a crown 12 comprising a tread 20 intended to come into contact with the ground during rolling and a crown reinforcement 14 extending in the crown 12 in the circumferential direction Z. The tyre 10 also comprises a sealing layer 15 for sealing against an inflation gas and being intended to delimit an internal cavity closed with a mounting support for the tyre 10 once the tyre 10 has been mounted on the mounting support, for example a rim. The sealing layer 15 is based on butyl.

[0165] The crown reinforcement 14 comprises a working reinforcement 16 comprising a working layer 18 and a hoop reinforcement 17 comprising a single hooping layer 19. Here, the working reinforcement 16 comprises a single working layer 18 and is, in this case, made up of the single working layer 18. In what follows, mention will be made, for the sake of simplification, of the working layer 18 without restating each time that this layer is unique. The hoop reinforcement 17 consists of the hooping layer 19.

[0166] The crown reinforcement 14 is surmounted radially by the tread 20. Here, the hoop reinforcement 17, here the hooping layer 19, is arranged radially outside the working reinforcement 16 and is therefore radially interposed between the working reinforcement 16 and the tread 20. In the embodiment illustrated in FIG. 2, the hoop reinforcement 17 has an axial width smaller than the axial width of the working layer 18. Thus, the hoop reinforcement is axially the narrowest of the working layer 18 and of the hoop reinforcement 17.

[0167] The tyre 10 comprises two sidewalls 22 extending the crown 12 radially inwards. The tyre 10 further comprises two beads 24 radially inside the sidewalls 22. Each sidewall 22 connects each bead 24 to the crown 12.

[0168] Each bead 24 comprises at least one circumferential reinforcing element 26, in this case a bead wire 28 surmounted radially by a mass of filling rubber 30.

[0169] The tyre 10 comprises a carcass reinforcement 32 anchored in each bead 24. The carcass reinforcement 32 extends in each sidewall 22 and radially internally at the crown 12. The crown reinforcement 14 is arranged radially between the tread 20 and the carcass reinforcement 32.

[0170] The carcass reinforcement 32 comprises a carcass layer 34. Here, the carcass reinforcement 32 comprises at least one carcass layer 34, and in this case comprises a single carcass layer 34 and here consists of the single carcass layer 34.

[0171] The carcass layer 34 comprises a portion 34T of the carcass layer 34 wound around each circumferential reinforcing element 26 so as to form in each bead 24 an axially inner portion 38 and an axially outer portion 40. The mass of filling rubber 30 is interposed between the axially inner and outer portions 38, 40. Other methods of anchoring the carcass layer 34 are possible, for example as described in U.S. Pat. No. 5,702,548.

[0172] Each working 18, hooping 19 and carcass 34 layer comprises an elastomeric matrix in which are embedded one or more filamentary reinforcing elements of the corresponding layer. These layers will now be described with reference to FIGS. 1 to 3.

[0173] The hoop reinforcement 17, here the hooping layer 19, is axially delimited by two axial edges 17A, 17B of the hoop reinforcement 17. The hoop reinforcement 17 comprises a plurality of hooping filamentary reinforcing elements 170 wound circumferentially helically so as to extend axially from the axial edge 17A to the other axial edge 17B of the hooping layer 17 in a main direction D1 of each hooping filamentary reinforcing element 170. The main direction D1 forms, with the circumferential direction Z of the tyre 10, an angle AF, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5°. Here, AF=5°.

[0174] The working layer 18 is axially delimited by two axial edges 18A, 18B of the working layer 18. The working layer 18 comprises working filamentary reinforcing elements 180 extending axially from the axial edge 18A to the other axial edge 18B of the working layer 18 substantially parallel to one another. Each working filamentary reinforcing element 180 extends in a main direction D2 of each working filamentary reinforcing element 180. The direction D2 forms, with the circumferential direction Z of the tyre 10, an angle AT, in absolute value, strictly greater than 10°, preferably ranging from 15° to 50° and more preferably ranging from 18° to 30°. Here, AT=24°.

[0175] The carcass layer 34 is axially delimited by two axial edges 34A, 34B of the carcass layer 34. The carcass layer 34 comprises carcass filamentary reinforcing elements 340 extending axially from the axial edge 34A to the other axial edge 34B of the carcass layer 34.

[0176] Each carcass filamentary reinforcing element 340 extends in a main direction D3 of each carcass filamentary reinforcing element 340 forming, with the circumferential direction Z of the tyre 10, an angle ACS, in absolute value, strictly less than 80° in a portion 34S of the carcass layer 34 extending axially in radial line with the working layer 18. Advantageously, in this portion 34S of the carcass layer 34 extending axially in radial line with the working layer 18, the main direction D3 of each carcass filamentary reinforcing element 340 forms, with the circumferential direction Z of the tyre 10, an angle ACS, in absolute value, greater than or equal to 10°, preferably ranging from 20° to 75° and more preferably ranging from 35° to 70°. Here, ACS=43°.

[0177] The portion 34S of the carcass layer 34 extending axially in line with the working layer 18 has an axial width equal to at least 40%, preferably at least 50%, of the axial width L of the working layer 18 and equal to at most 90%, preferably at most 80%, of the axial width L of the working layer 18 and in this case equal to 60% of the working layer 18. The median plane M of the tyre 10 intersects this portion 34S. More preferably, this portion 34S is axially centred on the median plane M of the tyre 10.

[0178] As illustrated in FIGS. 1 and 3, the main direction D3 of each carcass filamentary reinforcing element 340 forms, with the circumferential direction Z of the tyre 10, an angle ACF ranging, in absolute value, from 80° to 90° in at least one portion 34F of the carcass layer 34 extending radially in each sidewall 22. Here, ACF=90°.

[0179] Each portion 34F of the carcass layer 34 extending radially in each sidewall 22 has a radial height equal to at least 5%, preferably at least 15% and more preferably at least 30%, of the radial height H of the tyre 10 and equal to at most 80%, preferably at most 70% and more preferably at most 60%, of the radial height H of the tyre 10 and in this case equal to 41% of the radial height H of the tyre 10. The equatorial circumferential plane E of the tyre 10 intersects each portion 34F of the carcass layer 34 located in each sidewall 22.

[0180] The main direction D3 of each carcass filamentary reinforcing element 340 forms, with the circumferential direction Z of the tyre 10, an angle ACT, in absolute value, strictly greater than 0°, preferably ranging from 27° to 150° and more preferably ranging from 56° to 123°, in the wound portion 34T of the carcass layer 34.

[0181] Referring to FIG. 4, the carcass layer 34 has two circumferential end edges 35A, 35B facing each other and being in contact with one another. In this first embodiment, the carcass layer 34 extends circumferentially, forming a junction 56 by abutting face to face between the circumferential end edges 35A, 35B of the carcass layer 34 without forming a radial superposition between a carcass filamentary reinforcing element 340 of one of the circumferential end edges 35A, 35B and a carcass filamentary reinforcing element 340 of the other of the circumferential end edges 35A, 35B at least in the portion 34S of the carcass layer 34 extending axially in radial line with the working layer 18. In this case, the junction 56 by abutting face to face between the circumferential end edges 35A, 35B of the carcass layer 34 without forming a radial superposition between a carcass filamentary reinforcing element 340 of one of the circumferential end edges 35A, 35B and a carcass filamentary reinforcing element 340 of the other of the circumferential end edges 35A, 35B is present over the entire axial width of the carcass layer 34 between the two axial edges 34A, 34B of the carcass layer 34.

[0182] Thus, as illustrated in FIG. 2, the main direction D1 of each hooping filamentary reinforcing element 170, the main direction D2 of each working filamentary reinforcing element 180 and the main direction D3 of each carcass filamentary reinforcing element 340 form, with the circumferential direction Z of the tyre 10, in a portion PS′ of the tyre 10 lying axially between the axial edges 17A, 17B of the hoop reinforcement 17, paired angles different in absolute value. In addition, the main direction D2 of each working filamentary reinforcing element 180 and the main direction D3 of each carcass filamentary reinforcing element 340 form, with the circumferential direction Z of the tyre 10, in a portion PS of the tyre 10 lying axially between the axial edges 18A, 18B of the working layer 18, angles AT and ACS of opposite orientations. In this case, AT=−24° and ACS=+43°.

[0183] In the embodiment described, each portion PS, PS′ of the tyre 10 has an axial width equal to at least 40%, preferably at least 50%, of the axial width L of the working layer 18 and equal to at most 90%, preferably at most 80%, of the axial width L of the working layer 18 and in this case equal to 60% of the axial width L of the working layer 18. The median plane M of the tyre 10 intersects each portion PS, PS′ of the tyre 10. More preferably, each portion PS, PS′ of the tyre 10 is axially centred on the median plane M of the tyre 10.

[0184] Each working filamentary reinforcing element 180 is an assembly of two steel monofilaments that each have a diameter equal to 0.30 mm, the two steel monofilaments being wound together at a pitch of 14 mm.

[0185] Each carcass filamentary reinforcing element 340 conventionally comprises two multifilament strands, each multifilament strand consisting of a monofilament yarn of polyesters, here of PET, these two multifilament strands being individually over-twisted at 240 turns per metre in one direction and then twisted together at 240 turns per metre in the opposite direction. These two multifilament strands are wound in a helix around one another. Each of these multifilament strands has a count equal to 220 tex.

[0186] Each hooping filamentary reinforcing element 170 is formed for example by a cord as described in WO2016166056, WO2016166057, WO2019122620, WO2016091809, WO2016091810, WO2016091811 or WO2016091812.

[0187] The tyre 10 is obtained by a method which will be described with reference to FIGS. 5 to 13.

[0188] First, a wound working assembly 50 and a wound carcass assembly 52 are made by arranging the filamentary reinforcing elements 180 and 340 of each assembly 50 and 52 parallel to one another and embedding them, for example by calendering, in an uncrosslinked composition comprising at least one elastomer, the composition being intended to form an elastomeric matrix once crosslinked. A ply known as a straight ply is obtained, in which the filamentary reinforcing elements are parallel to one another and are parallel to the main direction of the ply. Then, portions of each straight ply are cut at a cutting angle and these portions are butted against one another so as to obtain a ply known as an angled ply, in which the filamentary reinforcing elements of the ply are parallel to one another and form an angle with the main direction of the ply equal to the cutting angle.

[0189] In the embodiment described, there is obtained on the one hand a single working ply 49 and a single carcass ply 51, the axial width of each of which, that is to say the dimension in a direction perpendicular to the longitudinal edges of each ply, is equal to the axial width respectively of each wound working 50 and carcass 52 assembly which will be formed subsequently.

[0190] In a first assembly step of a green blank, there is formed, by winding a sealing ply around a support 60 having a substantially cylindrical shape around its main axis A, the sealing layer 15 (not shown in FIG. 5). The support 60 has a substantially cylindrical laying surface with a radius equal to 235 mm.

[0191] Then, with reference to FIG. 5, radially outside the sealing layer, there is formed, by winding the carcass ply 51 around the support 60, the wound carcass assembly 52 intended to form the carcass layer 34. The wound carcass assembly 52 is axially delimited by two axial edges 52A, 52B of the carcass assembly 52 and comprises the carcass filamentary reinforcing elements 340 extending substantially parallel to one another axially from the axial edge 52A to the other axial edge 52B of the wound carcass assembly 52. Each carcass filamentary reinforcing element 340 extends, in the carcass ply 51, in a main direction K3 of each carcass filamentary reinforcing element 340 of the carcass ply 51. Referring to FIG. 9, the main direction K3 forms, with the circumferential direction z of the support 60, an initial angle A3 of each carcass filamentary reinforcing element 340, in absolute value, strictly greater than 0°, preferably ranging from 27° to 150° and more preferably ranging from 56° to 123°. Here, A3=75°.

[0192] Referring to FIG. 6, the wound carcass assembly 52 has two circumferential end edges 54A, 54B extending axially from the axial edge 52A to the other axial edge 52B of the carcass assembly 52. Each circumferential end edge 54A, 54B of the carcass assembly 52 is intended to form, in the tyre 10, each circumferential end edge 35A, 35B of the carcass layer 34.

[0193] During the step of forming the carcass assembly 52, the wound carcass assembly 52 is formed so as to form the junction 56 between the two circumferential end edges 54A, 54B by abutting face to face without forming a superposition between a carcass filamentary reinforcing element 340 of one of the circumferential end edges 54A, 54B and a carcass filamentary reinforcing element 340 of the other of the circumferential end edges 54A, 54B, at least in the portion 52S of the wound carcass assembly 52 intended to extend axially in radial line with the wound working assembly 50 and here over the entire axial width of the wound carcass assembly 52 between the two axial edges 52A, 52B of the wound carcass assembly 52.

[0194] The portion 52S of the wound carcass assembly 52 is intended to form the portion 34S of the carcass layer 34.

[0195] Referring to FIGS. 7 and 8, then, the two circumferential reinforcing elements 26 are arranged around the wound carcass assembly 52 and each axial edge 52A, 52B of the wound carcass assembly 52 is turned axially inwards so as to radially cover each circumferential reinforcing element 26 by each axial edge 52A, 52B of the wound carcass assembly 52 and to form a portion 59 of the wound carcass assembly 52 wound around each circumferential reinforcing element 26. The portion 59 of the wound carcass assembly 52 is intended to form the portion 34T of the carcass layer 34 wound around each circumferential reinforcing element 26 in the tyre.

[0196] There is shown in FIG. 9 a diagram illustrating the arrangement of the carcass filamentary reinforcing elements 340 at the end of the step of axially turning the axial edges 52A, 52B of the wound carcass assembly 52 around the circumferential reinforcing elements 26. This figure shows the initial angle A3 described above as well as the various portions 52S and 59.

[0197] Then, with reference to FIG. 10, there is formed, by winding the working ply 49, radially outside the wound carcass assembly 52, the wound working assembly 50 intended to form the working layer 18. The wound working assembly 50 is axially delimited by two axial edges 50A, 50B of the wound working assembly 50 and comprises the working filamentary reinforcing elements 180 extending substantially parallel to one another axially from the axial edge 50A to the other axial edge 50B of the wound working assembly 50. Each working filamentary reinforcing element 180 extends, in the working ply 49, in a main direction K2 of each working filamentary reinforcing element 180 in the working ply 49. With reference to FIG. 11, the main direction K2 forms, with the circumferential direction z of the support 60, an initial angle A2 of each working filamentary reinforcing element 180, in absolute value, strictly greater than 0°, preferably ranging from 4° to 60° and more preferably ranging from 16° to 47°. Here, A2=35°.

[0198] The wound carcass assembly 52 and the wound working assembly 50 then form an assembly 58 of substantially cylindrical shape around the main axis A of the support 60.

[0199] There is shown in FIG. 11 a diagram similar to that of FIG. 9 illustrating the arrangement of the carcass filamentary reinforcing elements 340 and the working filamentary reinforcing elements 180 at the end of the step of forming the wound working assembly 50. In this figure, the initial angles A2 and A3 have been shown.

[0200] The main direction K2 of each working filamentary reinforcing element 180 and the main direction K3 of each carcass filamentary reinforcing element 340 form, with the circumferential direction z of the support 60, in a portion AC of the assembly 58 lying axially between the axial edges 50A, 50B of the wound working assembly 50, initial angles A2 and A3 of opposite orientations. In this case, A2=−35° and A3=+75°.

[0201] Then, the assembly 58 of substantially cylindrical shape around the main axis A of the support 60 is deformed so as to obtain the assembly 58 of substantially toric shape around the main axis A of the support 60. The deformed assembly 58 illustrated in FIGS. 12 and 13 is obtained. The laying surface of the support 60 then has, at the level of the median plane of the support, a radius equal to 327 mm.

[0202] The assembly 58 of substantially cylindrical shape around the main axis A of the support 60 is deformed so as to obtain an assembly 58 of substantially toric shape around the main axis A of the support 60 so that the main direction K3 of each carcass filamentary reinforcing element 340 forms, with the circumferential direction z of the support 60, a final angle B3S of each carcass filamentary reinforcing element 340, in absolute value, strictly less than 80°, in the portion 52S of the wound carcass assembly 52 extending axially in radial line with the wound working assembly 50. Advantageously, the final angle B3S is, in absolute value, greater than or equal to 10°, preferably ranges from 20° to 75° and more preferably ranges from 35° to 70°. Here, B3S=43°.

[0203] The portion 52S of the wound carcass assembly 52 extending axially in radial line with the wound working assembly 50 has an axial width equal to at least 40%, preferably at least 50%, of the axial width I of the wound working assembly 50 and equal to at most 90%, preferably at most 80%, of the axial width I of the wound working assembly 50 and in this case is equal to 60% of the axial width I of the wound working assembly 50. The median plane m of the assembly 58 intersects this portion 52S. More preferably, this portion 52S is axially centred on the median plane m of the assembly 58.

[0204] The assembly 58 of substantially cylindrical shape around the main axis A of the support 60 is deformed so as to obtain the assembly 58 of substantially toric shape around the main axis A of the support 60 also so that the main direction K3 of each carcass filamentary reinforcing element 340 forms, with the circumferential direction z of the support 60, a final angle B3F of each carcass filamentary reinforcing element 340 ranging from 80° to 90°, in a portion 52F of the wound carcass assembly 52 intended to extend radially in each sidewall 22 of the tyre 10. Each portion 52F of the wound carcass assembly 52 is intended to form each portion 34F of the carcass layer 34.

[0205] Each portion 52F of the wound carcass assembly 52 intended to extend radially in each sidewall 22 has a radial height equal to at least 5%, preferably at least 15% and even more preferably at least 30%, of the radial height H of the manufactured tyre and equal to at most 80%, preferably at most 70% and even more preferably at most 60%, of the radial height H of the manufactured tyre, and in this case is equal to 41% of the radial height H of the manufactured tyre. The equatorial circumferential plane e of the assembly 58 intersects each portion 52F of the wound carcass assembly 52 intended to be located in each sidewall 22.

[0206] During the deformation step, the final angle B3T formed by the main direction K3 of each carcass filamentary reinforcing element 340, with the circumferential direction z of the support 60, in the wound portion 59 of the wound carcass assembly 52, is substantially identical to the initial angle A3 before the deformation step.

[0207] Finally, the assembly 58 of substantially cylindrical shape around the main axis A of the support 60 is deformed so as to obtain the assembly 58 of substantially toric shape around the main axis A of the support 60 also so that the main direction K2 of each working filamentary reinforcing element 340 forms, with the circumferential direction z of the support 60, a final angle B2 of each working filamentary reinforcing element 340, in absolute value, strictly greater than 10°. Advantageously, the final angle B2 ranges, in absolute value, from 15° to 50°, preferably from 18° to 30° and here B2=24°.

[0208] The main direction K2 of each working filamentary reinforcing element 180 and the main direction K3 of each carcass filamentary reinforcing element 340 form, with the circumferential direction z of the support 60, in a portion AC of the assembly 58 lying axially between the axial edges 50A, 50B of the wound working assembly 50, final angles B2 and B3 of opposite orientations. In this case, B2=−24° and B3=+43°.

[0209] During the method, a plurality of hooping filamentary reinforcing elements 170, preferably adhered, are embedded in an elastomeric matrix to form a hooping ply.

[0210] Then, there is arranged, radially around the assembly 58 previously formed on the support 60, a wound hooping assembly intended to form the hoop reinforcement 17. Here, the wound hooping assembly is formed by helical winding of the hooping ply on a toric shape and then the wound hooping assembly is transferred using a transfer ring radially outside the assembly previously formed. As a variant, the hooping ply may be directly wound circumferentially helically around the assembly previously formed so as to form the wound hooping assembly.

[0211] In the illustrated embodiment, the wound hooping assembly has an axial width smaller than the axial width of the wound working assembly 50. Thus, the wound hooping assembly is axially the narrowest of the wound working 50 and wound hooping assemblies.

[0212] The angle Al formed by the main direction K1 of each hooping filamentary reinforcing element 170 with the circumferential direction z of the support 60 is, in absolute value, less than or equal to 10°, preferably less than or equal to 7° and more preferably less than or equal to 5° and here equal to 5°.

[0213] The main direction K1 of each hooping filamentary reinforcing element 170, the main direction K2 of each working filamentary reinforcing element 180 and the main direction D3 of each carcass filamentary reinforcing element 340 form, with the circumferential direction z of the support 60, in a portion AC of the assembly 58 and of the wound hooping assembly lying axially between the axial edges of the wound hooping assembly, paired angles different in absolute value.

[0214] The portion AC′ of the assembly 58 and of the wound hooping assembly lying axially between the axial edges of the wound hooping assembly has an axial width equal to at least 40%, preferably at least 50%, of the axial width L of the wound working assembly 50 and at most 90%, preferably at most 80%, of the axial width L of the wound working assembly 50 and in this case 60% of the axial width L of the wound working assembly 50. The median plane m of the assembly 58 intersects this portion AC′. More preferably, this portion AC′ is axially centred on the median plane m of the assembly 58. Then, there is arranged, radially outside the wound hooping assembly, a strip of polymeric material intended to form the tread 20, so as to form a green blank of the tyre 10. In a variant, the strip of polymeric material intended to form the tread 20 may be arranged radially outside the hooping assembly, then this assembly may be transferred radially outside the assembly 58 previously formed on the support 60. In another variant, it is possible, after having arranged the wound hooping assembly radially around the assembly 58 previously formed on the support 60, to arrange the strip of polymeric material intended to form the tread 20.

[0215] The assembly thus formed, called the green blank of the tyre due to the presence of crosslinkable compositions in the uncrosslinked state, is then placed in a mould in order to proceed, on the one hand, to a moulding step and, on the other hand, to a step of crosslinking the crosslinkable compositions. During the moulding step, the green blank is radially and circumferentially expanded, for example by pressurizing a deformable membrane, so as to press the green blank against surfaces of a curing mould.

[0216] A second embodiment will now be described with reference to FIGS. 14 to 16. Elements similar to those of the first embodiment are denoted by identical references.

[0217] Unlike the tyre according to the first embodiment, the carcass layer 34 extends circumferentially, forming the junction 56 by overlapping so as to form a radial superposition between at least one carcass filamentary reinforcing element 340 of one of the circumferential end edges 35A, 35B and at least one carcass filamentary reinforcing element 340 of the other of the circumferential end edges 35A, 35B at least in the portion 34S of the carcass layer 34 extending axially in radial line with the working layer 18, and here over the entire axial width of the carcass layer 34 between the two axial edges 34A, 34B of the carcass layer 34.

[0218] In this case, the radially outermost circumferential end edge 35A of the carcass layer 34 covers the radially innermost circumferential end edge 35B of the carcass layer 34 with at most 4 carcass filamentary reinforcing elements 340, preferably at most 3 carcass filamentary reinforcing elements 340 and even more preferably at most 2 carcass filamentary reinforcing elements 340 and with at least 1 carcass filamentary reinforcing element 340 at least in the portion 34S of the carcass layer 34 extending axially in radial line with the working layer 18 and here over the entire axial width of the carcass layer 34 between the two axial edges 34A, 34B of the carcass layer 34. In this case, the radially outermost circumferential end edge 35A covers the radially innermost circumferential end edge 35B with 2 carcass filamentary reinforcing elements 340 over the entire axial width of the carcass layer 34 between the two axial edges 34A, 34B of the carcass layer 34. In order to determine the number of carcass filamentary reinforcing elements 340 of the radially outermost circumferential end edge 35A covering the radially innermost circumferential end edge 35B, there is determined the meridian plane N perpendicular to the axis of rotation of the tyre passing through the axial end of the carcass filamentary reinforcing element 340 of the radially innermost circumferential end edge 35B closest axially to the axial end face of this edge 35B. Any carcass filamentary reinforcing element 340 of the radially outermost circumferential end edge 35A located on the side of this meridian plane N overhanging the radially innermost circumferential end edge 35B is a carcass filamentary reinforcing element 340 of the radially outermost circumferential end edge 35A covering the radially innermost circumferential end edge 35B.

[0219] Unlike the method according to the first embodiment, in the second embodiment, the wound carcass assembly 52 is formed so as to form the junction 56 between the two circumferential end edges 54A, 54B by overlapping so as to form a radial superposition between at least one carcass filament reinforcing element 340 of one of the circumferential end edges 54A, 54B and at least one carcass filamentary reinforcing element 340 of the other of the circumferential end edges 54A, 54B, at least in the portion 52S of the wound carcass assembly 52 intended to extend axially in radial line with the wound working assembly 50. In this case, the wound carcass assembly 52 extends circumferentially, forming the junction 56 by overlapping so as to form a radial superposition between at least one carcass filamentary reinforcing element 340 of one of the circumferential end edges 54A, 54B and at least one carcass filamentary reinforcing element 340 of the other of the circumferential end edges 54A, 54B over the entire axial width of the wound carcass assembly 52 between the two axial edges 52A, 52B of the wound carcass assembly 52.

[0220] This forming step is carried out so that, if a step for forming the wound working assembly 50 was not carried out prior to the deformation step, the deformation step, carried out under identical deformation conditions, would lead to an opening of the junction 56. Here, as the step of forming the wound working assembly 50 is carried out prior to the deformation step, no opening of the junction 56 is observed despite a reduced number of filamentary reinforcing elements of the radially outermost circumferential end edge 54A of the wound carcass assembly 52 radially covering the radially innermost circumferential end edge 54B of the wound carcass assembly 52.

[0221] Athird embodiment will now be described with reference to FIGS. 17 to 19. Elements similar to those of the previous embodiments are denoted by identical references.

[0222] Unlike the tyre according to the first embodiment, the two circumferential end edges 35A, 35B are circumferentially spaced from one another at least in the portion of the carcass layer 34S extending axially in radial line with the working layer 18 and here over the entire axial width of the carcass layer 34 between the two axial edges 35A, 35B of the carcass layer 34. In the example, the circumferential end edges 35A, 35B of the carcass layer 34 are circumferentially spaced apart by an average distance of at most 2.5 mm, preferably of at most 2 mm and more preferably of at most 1 mm, in the portion 34S of the carcass layer 34 extending axially in radial line with the working layer 18 and here over the entire axial width of the carcass layer 34 between the two axial edges 35A, 35B of the carcass layer 34. In this case, the circumferential end edges 35A, 35B of the carcass layer 34 are circumferentially spaced apart by an average distance equal to 1 mm in the portion 34S of the carcass layer 34 extending axially in radial line with the working layer 18 and here over the entire axial width of the carcass layer 34 between the two axial edges 35A, 35B of the carcass layer 34. The average distance is calculated by taking the average of ten distances D measured equally distributed over the axial width of the portion 34S of the carcass layer 34 extending in radial line with the working layer 18. Each distance D is the straight distance between the two meridian planes N1, N2 parallel to the axis of rotation of the tyre and passing respectively through the circumferential end point of each circumferential end edge 35A, 35B.

[0223] Unlike the method according to the first embodiment, the wound carcass assembly 52 is formed so that the two circumferential end edges 54A, 54B are circumferentially spaced from one another at least in the portion 52S of the wound carcass assembly 52 intended to extend axially in radial line with the wound working assembly 50, and here over the entire axial width of the wound carcass assembly 52 between the two axial edges 52A, 52B of the wound carcass assembly 52. Similarly to the tyre, the circumferential end edges 54A, 54B of the wound carcass assembly 52 are circumferentially spaced apart by an average distance of at most 2.5 mm, preferably of at most 2 mm and more preferably of at most 1 mm, at least in the portion 52S of the wound carcass assembly 52 intended to extend axially in radial line with the wound working assembly 50, and here over the entire axial width of the wound carcass assembly 52 between the two axial edges 52A, 52B of the wound carcass assembly 52. In this case, the circumferential end edges 54A, 54B of the wound carcass assembly 52 are circumferentially spaced apart by an average distance substantially equal to the average distance measured in the tyre 10, that is to say 1 mm, in the portion 52S of the wound carcass assembly 52 intended to extend axially in radial line with the wound working assembly 50 and here over the entire axial width of the wound carcass assembly 52 between the two axial edges 52A, 52B of the wound carcass assembly 52. Similarly to the tyre 10, the average distance is calculated by taking the average of ten distances D measured equally distributed over the axial width of the portion 52S of the wound carcass assembly 52 intended to extend in radial line with the wound working assembly 50. Each distance D is the straight distance between the two meridian planes N1, N2 parallel to the main axis A of the support 60 and passing respectively through the axial end point of each circumferential end edge 52A, 52B.

[0224] The invention is not limited to the above-described embodiments.