TIRE COMPRISING A CIRCUMFERENTIAL CUT-OUT AND A DURABLE STIFFENING STRUCTURE AND ENABLING OPTIMIZED FLATTENING OF THE TREAD

Abstract

A tire (10) includes a stiffening structure (50) comprising stiffening elements (52) anchored in the crown (12) and extending into the toroidal cavity (35) between a radially inner anchor point (54A, 54B) and a radially outer anchor point (56A, 56B). The tread (14) has a profile height and comprises a plurality of ribs (102, 104, 106, 108, 110), two adjacent ribs being axially separated from each other by a main circumferential cut-out (112, 114, 116, 118) having a depth greater than or equal to 50% of the profile height. The radially outer anchor point (56A, 56B) is aligned with one of the ribs (102, 104, 106, 108, 110).

Claims

1.-13. (canceled)

14. A tire (10) comprising a crown (12) extended radially inward by two sidewalls (30A, 30B) then by two beads (32A, 32B), the crown (12) comprising a tread (14), the tire (10) having an internal surface (33) delimiting a toroidal inflation cavity (35) of the tire and a stiffening structure (50) comprising at least one stiffening element (52; 52A, 52B; 53) extending continuously in the toroidal cavity (35) from at least one of the sidewalls (30A, 30B) of the beads (32A, 32B) at least as far as the crown (12), wherein the or each stiffening element (52; 52A, 52B; 53) is anchored in the sidewall (30A, 30B) and/or the bead (32A, 32B) in or around at least one radially inner reinforcing structure in the sidewall (30A, 30B) and/or the bead (32A, 32B), wherein the or each stiffening element (52; 52A, 52B; 53) is anchored in the crown (12) in or around at least one radially outer reinforcing structure (70A, 70B; 73) in the crown (12), wherein the or each stiffening element (52; 52A, 52B; 53) comprises a portion (523) extending in the toroidal cavity (35) between: a radially inner anchor point (54A, 54B; 55A, 55B) at which the or each stiffening element (52; 52A, 52B; 53) passes through the internal surface (33) to be anchored in or around the or one of the radially inner reinforcing structures (60A; 60B; 61A, 61B), a radially outer anchor point (56A, 56B; 57A, 57B) at which the or each stiffening element (52; 52A, 52B; 53) passes through the inner surface (33) to be anchored in or around the or one of the radially outer reinforcing structures (70A, 70B; 73), and wherein the tread (14) has a profile height (Hs) and comprises a plurality of ribs (102, 104, 106, 108), two adjacent ribs being separated axially from one another by a main circumferential cut-out (112, 114, 116, 118) having a depth (Hr1, Hr2, Hr3, Hr4) greater than or equal to 50% of the profile height (Hs), the radially outer anchor point (56A, 56B; 57A, 57B) being aligned with one of the ribs (102, 104, 106, 108).

15. The tire (10) according to claim 14, wherein each bead (32A, 32B) comprises at least one circumferential reinforcing element (40A, 40B) intended to enable attachment of the tire (10) onto a mounting support of the tire (10), and wherein the radially inner reinforcing structure (60A, 60B; 61A, 61B) is distinct from the or each circumferential reinforcing element (40A, 40B) situated on a same side of a median plane (M) of the tire (10) as the sidewall (30A, 30B) and/or the bead (32A, 32B).

16. The tire (10) according to claim 14, wherein the stiffening structure (50) comprises a plurality of stiffening elements (52; 52A, 52B; 53) circumferentially distributed in the toroidal cavity (35).

17. The tire (10) according to claim 14, wherein the or each rib (102, 104, 106, 108) with which the or each radially outer anchor point (56A, 56B; 57A, 57B) is aligned is delimited axially by two axial edges (141, 142, 143, 144, 145, 146, 147, 148, 149, 150) defining a width L of the rib (102, 104, 106, 108), wherein a median plane (M1, M2, M3, M4, M5) of the rib is situated axially equidistantly from the two axial edges, and wherein the or each radially outer anchor point (56A, 56B; 57A, 57B) is at an axial distance l from the median plane of the rib such that 2?l/L?0.90.

18. The tire (10) according to claim 14, wherein the crown (12) is extended radially inward on each side of a median plane (M) of the tire (10) by respective first and second sidewalls (30A, 30B) and then by first and second beads (32A, 32B), wherein the or each stiffening element (52, 53) is anchored in or around: a first radially inner reinforcing structure (60A; 61A) arranged in the first sidewall (30A) and/or the first bead (32A), the or a plurality of the radially outer reinforcing structures (70A, 70B; 73) in the crown (12), a second radially inner reinforcing structure (60B; 61B) in the second sidewall (30B) and/or the second bead (32B), so that the or each stiffening element (52, 53) extends continuously from the first sidewall (30A) and/or the first bead (32A) as far as the second sidewall (30B) and/or the second bead (32B) in the crown (12), wherein the or each stiffening element (52, 53) comprises a portion (523) extending in the toroidal cavity (35) between: a first radially inner anchor point (54A, 55A) at which the or each stiffening element (52, 53) passes through the internal surface (33) to be anchored in or around the first radially inner reinforcing structure (60A, 61A), a first radially outer anchor point (56A, 57A) at which the or each stiffening element (52, 53) passes through the internal surface (33) to be anchored in or around the or a plurality of the radially outer reinforcing structures (70A, 70B; 73), and wherein the or each stiffening element (52, 53) comprises a portion (524) extending in the toroidal cavity (35) between: a second radially inner anchor point (54B, 55B) at which the or each stiffening element (52, 53) passes through the internal surface (33) to be anchored in or around the second radially inner reinforcing structure (60B, 61B), a second radially outer anchor point (56B, 57B) at which the or each stiffening element (52, 53) passes through the internal surface (33) to be anchored in or around the or a plurality of the radially outer reinforcing structures (70A, 70B; 73), each of the first and second radially outer anchor points (56A, 56B; 57A, 57B) being aligned with one of the ribs (102, 104, 106, 108).

19. The tire (10) according to claim 18, wherein the or each stiffening element (52; 53) is anchored in or around: the first radially inner reinforcing structure (60A; 61A), first and second radially outer reinforcing structures (70A, 70B; 73) in the crown (12), the second radially inner reinforcing structure (60B; 61B).

20. The tire (10) according to claim 14, wherein, the crown (12) being extended radially inward on each side of a median plane (M) of the tire (10) by a first and second sidewall (30A, 30B) and then by a first and a second bead (32A, 32B), the stiffening structure (50) comprises at least first and second stiffening elements (52A, 52B), wherein the or each first stiffening element (52A) is anchored in or around: a first radially inner reinforcing structure (60A, 61A) in the first sidewall (30A) and/or the first bead (32A), the or a plurality of the radially outer reinforcing structures (70A, 70B; 73) in the crown (12), wherein the or each second stiffening element is anchored in or around: a second radially inner reinforcing structure (60B, 61B) in the second sidewall (30B) and/or the second bead (32B), and the or a plurality of the radially outer reinforcing structures (70A, 70B; 73) in the crown (12), so that the or each of the first and second stiffening elements (52A, 52B) extends continuously in the toroidal cavity (35) from the first sidewall (30A) and/or the first bead (32A) and the second sidewall (30B) and/or the second bead (32B) as far as the crown (12) in the toroidal cavity (35), wherein the or each first stiffening element (52A) comprises a portion (523A) extending in the toroidal cavity (35) between: a first radially inner anchor point (54A; 55A) at which the or each stiffening element (52A) passes through the internal surface (33) to be anchored in or around the first radially inner reinforcing structure (60A; 61A), a first radially outer anchor point (56A; 57A) at which the or each first stiffening element (52A) passes through the internal surface (33) to be anchored in or around the or a plurality of the radially outer reinforcing structures (70A, 70B; 73), and wherein the or each second stiffening element (52B) comprises a portion (523B) extending in the toroidal cavity (35) between: a second radially inner anchor point (54B; 55B) at which the or each second stiffening element (52B) passes through the internal surface (33) to be anchored in or around the second radially inner reinforcing structure (60B; 61B), a second radially anchor point (56B; 57B) at which the or each second stiffening element (52B) passes through the internal surface (33) to be anchored in or around the or a plurality of the radially outer reinforcing structures (70A, 70B; 73), each of the first and second radially outer anchor points (56A, 56B; 57A, 57B) is aligned with one of the ribs (102, 104, 106, 108).

21. The tire (10) according to claim 20, wherein the or each first stiffening element (52A) is anchored in or around: the first radially inner reinforcing structure (60A, 61A), and a first radially outer reinforcing structure (70A, 70B) in the crown (12), and wherein the or each second stiffening element (52B) is anchored in or around: the second radially inner reinforcing structure (60B, 61B), and a second radially outer reinforcing structure (70A, 70B) in the crown (12) distinct from the first radially outer reinforcing structure (70A, 70B).

22. The tire (10) according to claim 19, wherein the first and second radially outer reinforcing structures (70A, 70B) are axially on either side of the median plane (M) of the tire (10).

23. The tire (10) according to claim 18, wherein each of the first and second radially inner anchor points (54A, 54B; 55A, 55B) and radially outer anchor points (56A, 56B; 57A, 57B) is such that: the first radially outer anchor points (56A; 57A) and radially inner anchor points (54A; 55A) are axially on a same side of the median plane (M) of the tire (10), the second radially outer anchor points (56B; 57B) and radially inner anchor points (54B; 55B) are axially on a same other side of the median plane (M) of the tire (10), and the portion (523; 533) extending between the first radially outer anchor points (56A; 57A) and radially inner anchor points (54A; 55A) and the portion (524; 534) extending between the second radially outer anchor points (56B; 57B) and radially inner anchor points (54B; 55B) do not cross over in the toroidal cavity (35).

24. The tire (10) according to claim 18, wherein each of the first and second beads (32A, 32B) comprises at least one circumferential reinforcing element (40A, 40B) intended to enable attachment of the tire (10) onto a mounting support of the tire (10), wherein the first radially inner reinforcing structure (60A; 61A) is distinct from the or each circumferential reinforcing element (40A) situated on a same first side of the median plane (M) of the tire (10) as the first sidewall (30A) and/or the first bead (32B), and wherein the second radially inner reinforcing structure (60B; 61B) is distinct from the or each circumferential reinforcing element (40B) situated on a same second side of the median plane (M) of the tire (10) as the second sidewall (30B) and/or the second bead (32B).

25. The tire (10) according to claim 18, wherein, the plurality of ribs (102, 104, 106, 108) comprising at least first and second ribs separated axially by the, one of the or a plurality of the main circumferential cut-outs (112, 114, 116, 118), each of the first and second radially outer anchor points (56A, 56B; 57A, 57B) is respectively aligned with each of the first and second ribs (102, 104, 106, 108).

26. The tire (10) according to claim 18, wherein each of the first and second radially outer anchor points (56A, 56B; 57A, 57B) is respectively aligned with the same rib (102, 104, 106, 108) of the plurality of ribs (102, 104, 106, 108).

27. The tire (10) according to claim 21, wherein the first and second radially outer reinforcing structures (70A, 70B) are axially on either side of the median plane (M) of the tire (10).

28. The tire (10) according to claim 20, wherein each of the first and second radially inner anchor points (54A, 54B; 55A, 55B) and radially outer anchor points (56A, 56B; 57A, 57B) is such that: the first radially outer anchor points (56A; 57A) and radially inner anchor points (54A; 55A) are axially on a same side of the median plane (M) of the tire (10), the second radially outer anchor points (56B; 57B) and radially inner anchor points (54B; 55B) are axially on a same other side of the median plane (M) of the tire (10), and the portion (523; 533) extending between the first radially outer anchor points (56A; 57A) and radially inner anchor points (54A; 55A) and the portion (524; 534) extending between the second radially outer anchor points (56B; 57B) and radially inner anchor points (54B; 55B) do not cross over in the toroidal cavity (35).

29. The tire (10) according to claim 20, wherein each of the first and second beads (32A, 32B) comprises at least one circumferential reinforcing element (40A, 40B) intended to enable attachment of the tire (10) onto a mounting support of the tire (10), wherein the first radially inner reinforcing structure (60A; 61A) is distinct from the or each circumferential reinforcing element (40A) situated on a same first side of the median plane (M) of the tire (10) as the first sidewall (30A) and/or the first bead (32B), and wherein the second radially inner reinforcing structure (60B; 61B) is distinct from the or each circumferential reinforcing element (40B) situated on a same second side of the median plane (M) of the tire (10) as the second sidewall (30B) and/or the second bead (32B).

30. The tire (10) according to claim 20, wherein, the plurality of ribs (102, 104, 106, 108) comprising at least first and second ribs separated axially by the, one of the or a plurality of the main circumferential cut-outs (112, 114, 116, 118), each of the first and second radially outer anchor points (56A, 56B; 57A, 57B) is respectively aligned with each of the first and second ribs (102, 104, 106, 108).

31. The tire (10) according to claim 20, wherein each of the first and second radially outer anchor points (56A, 56B; 57A, 57B) is respectively aligned with the same rib (102, 104, 106, 108) of the plurality of ribs (102, 104, 106, 108).

Description

[0239] Following the generic description that has just been given, the invention will be better understood on reading the following detailed description given by way of non-limiting example only and with reference to the drawings, in which:

[0240] FIG. 1, comprising FIGS. 1A, 1B, 10, depicts a tyre in accordance with a first embodiment of the invention, FIG. 1A being a view in a meridian section plane parallel to the axis of rotation of the tyre, FIGS. 1B and 10 being views of the interior of the tyre from FIG. 1A in different directions,

[0241] FIG. 2 is a cutaway view of the tyre from FIG. 1 depicting the arrangement of the filar reinforcing elements in the crown,

[0242] FIG. 3 is a diagram depicting the arrangement of the stiffening structure of the tyre from FIG. 1,

[0243] FIGS. 4 and 5 are detail views of the zones IV and V in FIG. 1A, respectively,

[0244] FIGS. 6 to 10 are views analogous to that of FIG. 1A of tyres in accordance with second, third, fourth, fifth and sixth embodiments, respectively,

[0245] FIGS. 11 to 13 are views analogous to FIGS. 3 to 5 of the tyre from FIG. 10 in accordance with the sixth embodiment,

[0246] FIGS. 14 and 15 are views analogous to that of FIG. 1A of tyres in accordance with seventh and eighth embodiments,

[0247] FIGS. 16 and 17 are views on a meridian section plane parallel to the axis of rotation of the tyre, respectively of the tyre from FIG. 1A and a control tyre not conforming to the invention subjected to a lateral force F,

[0248] FIGS. 18 and 19 are views of the contact area of the tyre from FIG. 1A and of the control tyre not conforming to the invention subjected to the lateral force F, and

[0249] FIG. 20 comprising FIGS. 20A, 20B, FIG. 21 comprising FIGS. 21A, 21B, FIG. 22 and FIG. 23 comprising FIGS. 23A and 23F depict tooling and a method for manufacturing the tyre according to the first embodiment.

[0250] In the figures relating to the tyre there has been represented a system of axes X, Y, Z corresponding to the usual axial direction (Y), radial direction (Z) and circumferential direction (X), respectively, of a tyre.

[0251] A tyre conforming to the invention and designated by the general reference 10 has been represented in FIGS. 1A, 1B, 10. The tyre 10 has a substantially toroidal shape about an axis of revolution substantially parallel to the axial direction Y. The tyre 10 is intended for a passenger vehicle and has a dimension 275/35ZR19. The tyre 10 is represented in the various figures in the new state, that is to say as yet unused.

[0252] The tyre 10 includes a crown 12 including a tread 14 intended to come into contact with the ground when rolling and a crown reinforcement 16 extending in the crown 12 in the circumferential direction X. The tyre 10 also includes a layer 18 gastight for an inflation gas.

[0253] The tread 14 is delimited axially by axial edges 141, 142 passing through each point N arranged on either side of the median plane M and for which the angle between the tangent T to the rolling surface 15 and a straight line segment R parallel to the axial direction Y passing through this point is equal to 30?. The tread 14 comprises five ribs 102, 104, 106, 108, 110 comprising two lateral ribs 102, 110 and three central ribs 104, 106, 108. The tread 14 also comprises four main circumferential cut-outs 112, 114, 116, 118 and five secondary circumferential cut-outs 122, 124, 126, 128, 130 each formed in a respective one of the ribs 102, 104, 106, 108, 110.

[0254] The lateral rib 102 is arranged axially between the axial edge 141 and the main circumferential cut-out 112 adjacent to the axial edge 141. The lateral rib 102 is delimited axially by an axially outer axial edge 141 coinciding with the axial edge 141 and by an inner axial edge 143 defining a width Ln1 of the lateral rib 102.

[0255] The lateral rib 110 is arranged axially between the axial edge 142 and the main circumferential cut-out 118 adjacent to the axial edge 142. The lateral rib 110 is delimited axially by an axially outer axial edge 142 coinciding with the axial edge 142 and by an inner axial edge 144 defining a width Ln5 of the lateral rib 110.

[0256] The central rib 104 is arranged axially between the main circumferential cut-outs 112, 114. The central rib 104 is delimited axially by an axially outer axial edge 145 and by an inner axial edge 146 defining a width Ln2 of the central rib 104.

[0257] The central rib 106 is arranged axially between the main circumferential cut-outs 114, 116. The central rib 106 is delimited axially by an axially outer axial edge 147 and by an inner axial edge 148 defining a width Ln3 of the central rib 106.

[0258] The central rib 108 is arranged axially between the main circumferential cut-outs 116, 118. The central rib 108 is delimited axially by an axially outer axial edge 149 and by an inner axial edge 150 defining a width Ln4 of the central rib 108.

[0259] The lateral rib 102 and the central rib 104 are adjacent and separated axially from one another by the main circumferential cut-out 112. The central ribs 104, 106 are adjacent to and separated axially from one another by the main circumferential cut-out 114. The central ribs 106, 108 are adjacent to and axially separated from one another by the main circumferential cut-out 116. The lateral rib 110 and the central rib 108 are adjacent to and separated axially from one another by the main circumferential cut-out 118.

[0260] When new, the tyre 10 has a profile height Hs equal here to 8.6 mm. Each main circumferential cut-out 112 to 118 has a respective depth Hr1, Hr2, Hr3, Hr4 greater than or equal to 50%, preferably greater than or equal to 75%, of the profile height Hs. In this instance Hr1=Hr4=7.7 mm and Hs=Hr2=Hr3=8.6 mm. Each main circumferential cut-out 112 to 118 has a width designated by the reference Lr1, Lr2, Lr3, Lr4m, respectively, and greater than or equal to 1.0 mm, preferably greater than equal to 5.0 mm, more preferably greater than or equal to 8.0 mm and even more preferably from 8.0 mm to 15.0 mm. Here Lr1=Lr4=7.7 mm and Lr2=11.5 mm and Lr3=13.5 mm.

[0261] Each axial width Ln2, Ln3, Ln4 is from 20 mm to 60 mm. Here Ln2=Ln3=Ln4=35 mm and each axial width Ln1, Ln5 is from 20 mm to 100 mm. Here Ln1=48 mm Ln5=43 mm. Each rib 102 to 110 has a median plane designated by the reference M1, M2, M3, M4, M5, respectively, and situated axially equidistantly from each axial edge of said rib.

[0262] The crown reinforcement 16 comprises a working reinforcement 20 and a wrapping reinforcement 22. The working reinforcement 20 comprises at least one working layer and here comprises two working layers 24, 26. In this instance the working reinforcement 20 consists of two working layers 24, 26. The radially inner working layer 24 is arranged radially inside the radially outer working layer 26.

[0263] The wrapping reinforcement 22 comprises at least one wrapping layer and here comprises a wrapping layer 28. Here the wrapping reinforcement 22 consists of the wrapping layer 28.

[0264] The crown reinforcement 16 is surmounted radially by the tread 14. Here the wrapping reinforcement 22, here the wrapping layer 28, is arranged radially outside the working reinforcement 20 and is therefore radially interleaved between the working reinforcement 20 and the tread 14.

[0265] The tyre 10 comprises first and second sidewalls 30A, 30B extending the crown 12 radially inwards. The second sidewall 30B is situated on the other side of the median plane M to the first sidewall 30A. The tyre 10 further includes first and second beads 32A, 32B respectively extending each first and second sidewalls 30A, 30B radially inwards. The second bead 32B is situated on the other side of the median plane M to the first bead 32A. Each of the first and second sidewalls 30A, 30B connects each first and second bead 32A, 32B respectively to the crown 12. An internal surface 33 intended to be in contact with the inflation gas of the tyre 10 delimits a toroidal inflation cavity 35 of the tyre. Here the internal surface 33 is borne by the gastight layer 18. Each of the first and second beads 32A, 32B respectively comprises first and second circumferential reinforcing elements 40A, 40B, here a bead wire enabling attachment of the tyre 10 onto a mounting support of the tyre 10, for example a rim.

[0266] The tyre 10 comprises a carcass reinforcement 34 anchored in each of the first and second beads 32A, 32B, and in this instance is wound around each of the first and second circumferential reinforcing elements 40A, 40B. The carcass reinforcement 34 extends radially in each sidewall 30 and radially inside the axial crown reinforcement 16 in the crown 12. The crown reinforcement 16 is arranged radially between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 comprises at least one carcass layer and here comprises only one carcass layer 36. In this instance the carcass reinforcement 34 consists of the only carcass layer 36.

[0267] Each of the working layers 24, 26, the wrapping layer 28 and the carcass layer 36 comprise an elastomer matrix in which are embedded one or more filar reinforcement elements of the corresponding layer. These layers are described next with reference to FIG. 2.

[0268] The wrapping reinforcement 22, here the wrapping layer 28, is delimited axially by two axial edges 28A, 28B of the wrapping reinforcement 22. The wrapping reinforcement 22 comprises one or more wrapping filar reinforcing elements 280 wound circumferentially and helically so as to extend axially from the axial edge 28A to the other axial edge 28B of the wrapping layer 28 in a main direction DO of each wrapping filar reinforcing element 280. The main direction DO forms with the circumferential direction X of the tyre 10 an angle AF with 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?.

[0269] The radially inner working layer 24 is delimited axially by two axial edges 24A, 24B. The radially inner working layer 24 comprises working filar reinforcing elements 240 extending axially from the axial edge 24A to the other axial edge 24B substantially parallel to one another in a main direction D1. In an analogous manner the radially outer working layer 26 is delimited axially by two axial edges 26A, 26B. The radially outer working layer 26 comprises working filar reinforcing elements 260 extending axially from the axial edge 26A to the other axial edge 26B substantially parallel to one another in a main direction D2. The main direction D1 in which each working filar reinforcement element 240 of the radially inner working layer 24 extends and the main direction D2 in which each working filar reinforcing element 260 of the other radially outer working layer 26 extends form with the circumferential direction X of the tyre 10 respective angles AT1 and AT2 with opposite orientations. Each main direction D1, D2 forms with the circumferential direction X of the tyre 10 a respective angle AT1, AT2 with absolute value strictly greater than 10?, preferably from 15? to 50? and more preferably from 15? to 30?. Here AT1=?26? and AT2=+26?.

[0270] The carcass layer 36 is delimited axially by two axial edges 36A, 36B. The carcass layer 36 comprises carcass filar reinforcing elements 340 extending axially from the axial edge 36A to the other axial edge 36B of the carcass layer 36 in a main direction D3 forming with the circumferential direction X of the tyre 10 an angle AC with absolute value greater than or equal to 60?, preferably from 80? to 90?, and here AC=+90?.

[0271] Each wrapping filar reinforcing element 280 conventionally comprises two multifilament plies comprising a multifilament ply consisting of an aliphatic polyamide monofilament ply, here of nylon with denier equivalent to 140 tex and a multifilament ply consisting of an aromatic polyamide monofilament ply, here of aramide with a denier equivalent to 167 tex, these two multifilament plies being advantageously coiled at 290 turns per metre in one direction and then coiled together at 290 turns per metre in the opposite direction. These two multifilament plies are wound helically around one another. Obviously, any other wrapping filar reinforcing element known to the person skilled in the art could be used.

[0272] Each working filar reinforcing element 240, 260 is an assembly of four steel monofilaments comprising an internal layer of two steel monofilaments initially wound helically with an infinite pitch and an outer layer of two steel monofilaments initially wound helically with a pitch of 14.3 mm in one direction, the four monofilaments then being wound at the pitch of 14.3 mm in the opposite direction, each steel monofilament having a diameter equal to 0.26 mm. In another variant each working filar reinforcing element 240, 260 consists of a steel monofilament having a diameter equal to 0.30 mm. In a further variant each working filar reinforcing element is an assembly of two monofilaments wound helically together having a diameter equal to 0.30 mm. More generally, the steel monofilaments have diameters from 0.25 mm to 0.32 mm. Obviously, any other working filar reinforcing element known to the person skilled in the art could be used.

[0273] Each carcass filar reinforcing element 340 conventionally comprises two multifilament plies, each multifilament ply consisting of a polyester, here PET, monofilament ply, these two multifilament plies being wound helically and individually at 270 turns per metre in one direction and then coiled helically together at 270 turns per metre in the opposite direction. Each of these multifilament strands has a denier equivalent to 334 tex. In other variants deniers equivalent to 144 tex and twists equal to 420 turns per metre or deniers equivalent to 220 tex and twists equal to 240 turns per metre could be used.

[0274] Referring to FIGS. 1A, 1B and 10, the tyre 10 comprises a stiffening structure 50 comprising a plurality of stiffening elements 52 extending continuously in the toroidal cavity 35. The stiffening elements 52 are distributed circumferentially in the toroidal cavity 35. The stiffening elements 52 are distributed circumferentially with a repetition angular pitch preferably between 1 degree and 5 degrees inclusive, preferably between 1 degree and 3 degrees inclusive. Depending on the dimensions of the tyre 10, the stiffening structure 50 therefore has between 72 and 360 stiffening elements 52, preferably between 120 and 360 stiffening elements 52, and here 240 stiffening elements 52. The number of stiffening elements 52 makes it possible to achieve a good trade-off between a number of stiffening elements 52 that is on the one hand sufficiently high to obtain effective stiffening of the tyre 10 and on the other hand sufficiently moderate to be able to arrange a corresponding number of passages 1500 in the core 1000 without excessively weakening the structure of the core 1000 or complicating extraction from the mould, as explained hereinafter.

[0275] Each stiffening element 52 is a textile filar stiffening element, consisting here of an assembly of three polyester, here PET, multifilament plies, these three multifilament plies being individually wound at 220 turns per metre in one direction and then wound together at 220 turns per metre in the opposite direction. Each of these multifilament plies has a denier equivalent to 220 tex.

[0276] Each filar stiffening element 52 extends continuously from the first sidewall 30A and/or the first bead 32A as far as the second sidewall 30B and/or the second bead 32B in the crown 12 and here from the first sidewall 30A as far as the second sidewall 30B in the crown 12. The main direction in which each stiffening element 52 extends in the toroidal cavity 35 forms with the circumferential direction X an angle in absolute value from 85? to 90?.

[0277] The stiffening structure 50 also comprises radially inner first and second reinforcing structures 60A, 60B respectively in the first and second sidewalls 30A, 30B and/or the first and second beads 32A, 32B, and here respectively in each of the first and second sidewalls 30A, 30B. Each of the radially inner first and second reinforcing structures 60A, 60B is respectively distinct from each of the first and second circumferential reinforcing elements 40A, 40B situated on the same side of the median plane as each of the first and second sidewalls 30A, 30B, respectively. In this instance each of the radially inner first and second reinforcing structures 60A, 60B is respectively arranged radially outside each of the first and second circumferential reinforcing elements 40A, 40B.

[0278] Each of the radially inner first and second reinforcing structures 60A, 60B respectively comprises first and second metal filar reinforcing elements 62A, 62B here comprising an assembly of an inner layer of four 0.35 mm metal elementary monofilaments wound helically at the pitch of 5 mm and an outer layer of 0.35 mm metal elementary monofilaments wound helically around the internal layer at the pitch of 10 mm. Each filar reinforcing element 62A, 62B extends in a main direction forming with the circumferential direction X an angle less than or equal to 10?, preferably less than or equal to 5? and here substantially zero, as can be seen in FIGS. 3 and 4. Each of the first and second filar reinforcing elements 62A, 62B of each of the first and second radially inner reinforcing structures 60A, 60B is wound circumferentially over at most two complete turns and here over at most one complete turn around the axis of revolution Y.

[0279] In order to ensure optimum anchoring of each stiffening element 52, each of the first and second radially inner reinforcing structures 60A, 60B has relatively high stiffness in extension and in flexing. Moreover, and still with the aim of optimising the anchoring of each stiffening element 52, each of the first and second radially inner reinforcing structures 60A, 60B is buried in a mass of one or more, preferably elastomer, materials, the nominal secant modulus at 10% extension is greater than or equal to 20 MPa, preferably to 30 MPA and here equal to 56 MPa. The measurement is effected in accordance with French standard NF T 46-002 of September 1988. There is measured in second elongation (that is to say after accommodation) the calculated nominal secant modulus with respect to the initial section of the test specimen (or apparent stress in MPa) at 10% elongation. This measurement in tension is effected under normal conditions of temperature (23?2? C.) and of relative humidity (50?5%) in accordance with French standard NF T 40-101 (December 1979).

[0280] The stiffening structure 50 further comprises first and second radially outer reinforcing structures 70A, 70B in the crown 12. The first and second radially outer reinforcing structures 70A, 70B are arranged axially on either side of the median plane M of the tyre 10 and here substantially symmetrically with respect to the median plane M of the tyre 10. Each of the radially outer reinforcing structures 70A, 70B is arranged radially inside the carcass reinforcement 34.

[0281] The first and second radially outer reinforcing structures 70A, 70B respectively comprise first and second textile filar reinforcing elements 72A, 72B here comprising an assembly of two multifilament plies each consisting of an aromatic polyamide monofilament ply here of aramide with a denier equivalent to 330 tex, and a multifilament ply consisting of an aliphatic polyamide monofilament ply, here of nylon with a denier equivalent to 188 tex, each of the multifilament plies being individually coiled helically at 270 turns per metre in one direction and then coiled helically together at 270 turns per metre in the opposite direction. These three multifilament strands are helically wound one around the other. Each of the filar forcing elements 72A, 72B extends in a main direction forming with the circumferential direction X an angle less than or equal to 10?, preferably less than or equal to 5?, and here substantially zero, as can be seen in FIGS. 3 and 5. Each of the first and second filar reinforcing elements 72A, 72B of each of the first and second radially outer reinforcing structures 70A, 70B is wound circumferentially over at least two complete turns and at most ten complete turns about the axis of revolution Y, and here over four complete turns about the axis of revolution.

[0282] In order to ensure optimum anchoring of each stiffening element 52, each of the first and second radially outer reinforcing structures 70A, 70B has a stiffness in extension that is relatively high and a stiffness in flexing that is relatively low in order to limit overwrapping of the crown 12 and not to risk deterioration of the flattening of the tread 14. Moreover, still with the aim of optimising the anchoring of each stiffening element 52, each of the first and second radially outer reinforcing structures 70A, 70B is buried in a mass of one or more, preferably elastomer, materials the nominal secant modulus of which at 10% elongation is greater than or equal to 2.5 Mpa, preferably less than or equal to 15 MPa, more preferably less than or equal to 10 MPa and even more preferably less than or equal to 5 Mpa, and here equal to 3 MPa.

[0283] Each stiffening element 52 is anchored in the first sidewall 30A around the first radially inner reinforcing structure 60A and in the second sidewall 30B around the second radially inner reinforcing structure 60B. Here each stiffening element 52 is wound at least in part around each of the first and second filar reinforcing elements 62A, 62B. Each stiffening element 52 is also anchored, in the crown 12, around each of the first and second radially outer reinforcing structures 70A, 70B. Here each stiffening element 52 is wound at least in part around each of the first and second filar reinforcing elements 72A, 72B.

[0284] Each stiffening element 52 passes through the internal surface 33 at a first radially inner anchor point 54A to be anchored around the first radially inner reinforcing structure 60A and a first radially outer anchor point 56A to be anchored around the first radially outer reinforcing structure 70A. The stiffening element 52 passes through the internal surface 33 at a second radially inner anchor point 54B to be anchored around the second radially inner reinforcing structure 60B and at a second radially outer anchor point 56B to be anchored around the second radially outer reinforcing structure 70B.

[0285] Accordingly, each stiffening element 52 comprises portions 521, 522 respectively buried in each sidewall 30A, 30B, first and second portions 523, 524 extending in the toroidal cavity 35 respectively between the first radially inner anchor point 54A and radially outer anchor point 56A and between the second radially inner anchor point 54B and radially outer anchor point 56B as well as a portion 525 buried in the crown 12 between the first and second portions 523, 524.

[0286] In order to ensure optimal anchoring of each stiffening element, each portion 521, 522 has a relatively long length, here greater than or equal to 20 mm, and is coupled to a length greater than or equal to 1 mm of each of the radially inner reinforcing structures 60A, 60B.

[0287] As depicted in FIG. 1A the first radially outer anchor point 56A is axially on the same side as the first radially inner anchor point 54A and the first radially inner structure 60A relative to the median plane M. The second radially outer anchor point 56B is axially on the same other side as the second radially inner anchor point 54B and the second radially inner structure 60B relative to the median plane M. Each of the first and second radially inner anchor points 54A, 54B and the first and second radially outer anchor points 56A, 56B is arranged so that the first and second portions 523, 524 do not cross over in the toroidal cavity 35.

[0288] Each of the first and second radially outer anchor points 56A, 56B is at a respective axial distance D1, D2 at most equal to 0.45?SW, preferably from 0.05?SW to 0.45?SW, from the median plane M of the tyre 10, SW being the nominal section width of the tyre 10. The nominal section width is as defined in the manual of the ETRTO 2020 standard and can in particular be seen in the markings applied to at least one of the sidewalls 30A, 30B of the tyre 10 in the form SW/AR ? V?? where SW designates the nominal section width, AR designates the nominal aspect ratio, ? designates the structure and is either R or ZR, V designates the nominal rim diameter, ? designates the load index and ? designates the speed symbol. Here D1=D2=45 mm.

[0289] Each of the first and second radially inner anchor points 54A, 54B is at a respective radial distance B1, B2 from 0.10?H to 0.50?H, preferably from 0.10?H to 0.35?H, from the radially innermost point of the tyre 10, H being the section height of the tyre defined by H=SW?AR/100 where SW is the nominal section width and AR is the nominal aspect ratio of the tyre in accordance with manual of the ETRTO 2020 standard. The nominal section width SW and the nominal aspect ratio AR are those in the dimensions marking on the sidewall of the tyre and conform to the manual of the ETRTO 2020 standard. Here B1=B2=30 mm.

[0290] The first and second radially outer anchor points 56A, 56B are aligned with one of the ribs and here respectively with the central ribs 104 and 108 that are separated by two circumferential cut-outs 114, 116. The first and second radially outer anchor points 56A, 56B are at a respective axial distance l2, l4 from each median plane M2, M4 such that 2?l2/Ln2 0.90 and 2?l4/Ln4?0.90, preferably 2?l2/Ln2?0.75 and 2?l4/Ln4?0.75, more preferably 2?l2/Ln2?0.50 and 2?l4/Ln4?0.50 and even more preferably 2?l2/Ln2?0.25 and 2?l4/Ln2?0.25. Here l2=l4=1 mm and 2?l2/Ln2=2?l4/Ln4=0.06.

[0291] As is depicted in FIGS. 3 and 4, the stiffening elements 52 form a continuous stiffening element so as to trace out a boustrophedon path between the first sidewall 30A and the second sidewall 30B in the crown 12. Alternatively, separate and therefore discontinuous stiffening elements 52 could equally well be envisaged.

[0292] There has been represented in FIG. 6 a tyre in accordance with a second embodiment of the invention. Elements analogous to those of the tyre in accordance with the first embodiment are designated by identical references.

[0293] Unlike the tyre in accordance with the first embodiment, the stiffening structure 50 of the tyre 10 in accordance with the second embodiment comprises first and second stiffening elements 52A, 52B distinct from one another. Each first stiffening element 52A is anchored around the first radially inner reinforcing structure 60A arranged in the first sidewall 30A and around the first radially outer reinforcing structure 70A arranged in the crown 12. Each second stiffening element 52B is anchored around a second radially inner reinforcing structure 60B arranged in the second sidewall 30B and around the second radially outer reinforcing structure 70B arranged in the crown 12 so that each first stiffening element 52A extends continuously in the toroidal cavity 35 from the first sidewall 30A as far as the crown 12 and so that each second stiffening element 52B extends continuously in the toroidal cavity 35 from the second sidewall 30B to the crown 12.

[0294] The first stiffening elements 52A form a first continuous stiffening element so as to trace out a boustrophedon path between the first sidewall 30A and the crown 12. The second stiffening elements 52B form a second continuous stiffening element so as to trace out a boustrophedon path between the first sidewall 30B and the crown 12.

[0295] Each of the first and second stiffening elements 52A, 52B comprises first and second portions 521A, 521B respectively buried in the first and second sidewalls 30A, 30B, first and second portions 523A, 524B extending in the toroidal cavity 35 respectively between the first radially inner anchor point 54A and the first radially exterior anchor point 56A and between the second radially inner anchor point 54B and the second radially outer anchor point 56B, as well as first and second portions 525A, 525B buried in the crown 12. For clarity there has been represented in FIG. 6 a part of each of the first and second portions 523A, 523B of stiffening elements 52A, 52B continuous with each of the first and second stiffening elements 52A, 52B but outside the meridian plane of FIG. 6.

[0296] Just as in the first embodiment, the first radially outer anchor point 56A is axially on the same side as the first radially inner anchor point 54A and as the first radially inner structure 60A relative to the median plane M. The second radially outer anchor point 56B is arranged on the same side as the second radially inner anchor point 54B and as the second radially inner structure 60B relative to the median plane M. Each of the first and second radially inner anchor points 54A, 54B and radially outer anchor points 56A, 56B is arranged so that the first and second portions 523A, 523B do not cross over in the toroidal cavity 35.

[0297] In a variant of the second embodiment that is not represented there could be envisaged an embodiment analogous to the second embodiment but in which the stiffening structure 50 does not comprise two radially outer reinforcing structures but a single radially outer reinforcing structure, as is the case for the third embodiment described hereinafter.

[0298] There has been represented in FIG. 7 a tyre in accordance with a third embodiment of the invention. Elements analogous to those of the tyres in accordance with the previous embodiments are designated by identical references.

[0299] Unlike the tyre in accordance with the first embodiment, the stiffening structure of the tyre 10 in accordance with the third embodiment comprises a single radially outer reinforcing structure 73. Each stiffening element 52 is anchored around the first radially inner reinforcing structure 60A, around the radially outer reinforcing structure 73 in the crown 12 and around the second radially inner reinforcing structure 60B so that each stiffening element 52 extends continuously from the first sidewall 30A to the second sidewall 30B in the crown 12.

[0300] Unlike the first embodiment, each of the first and second radially outer anchor points 56A, 56B is aligned with the same rib, here the central rib 106.

[0301] There has been represented in FIG. 8 a tyre in accordance with a fourth embodiment of the invention. Elements analogous to those of the tyres in accordance with the previous embodiments are designated by identical references.

[0302] Unlike the first embodiment, the stiffening structure 50 comprises axially outer anchor stiffening elements 52 and axially inner anchor stiffening elements 53. The stiffening structure 52 comprises first and second radially outer reinforcing structures 70A, 70B arranged on either side of and substantially symmetrical with respect to the median plane M.

[0303] Each axially outer anchor stiffening element 52 is anchored around the first radially inner reinforcing structure 60A, around the first and second radially outer reinforcing structure 70A, 70B and around the second radially inner reinforcing structure 60B so that each axially outer anchor stiffening element 52 extends continuously from the first sidewall 30A to the second sidewall 30B in the crown 12. Each axially outer anchor stiffening element 52 comprises a first portion 523 extending in the toroidal cavity 35 between a first radially inner anchor point 54A at which each axially outer anchor stiffening element 52 passes through the internal surface 33 to be anchored around the first radially inner reinforcing structure 60A and a first radially outer anchor point 56A at which each axially outer anchor stiffening element 52 passes through the internal surface 33 to be anchored around the first and second radially outer reinforcing structures 70A, 70B. Each axially outer anchor stiffening element 52 comprises a second portion 524 extending in the toroidal cavity 35 between a second radially inner anchor point 54B at which each axially outer anchor stiffening element 52 passes through the internal surface 33 to be anchored around the second radially inner reinforcing structure 60B and a second radially outer anchor point 56B at which each axially outer anchor stiffening element 52 passes through the internal surface 33 to be anchored around the first and second radially outer reinforcing structures 70A, 70B.

[0304] Each axially inner anchor stiffening element 53 is anchored around the first radially inner reinforcing structure 60A, around the first and second radially outer reinforcing structures 70A, 70B and around the second radially inner reinforcing structure 60B so that each second stiffening element 53 extends continuously from the first sidewall 30A as far as the second sidewall 30B in the crown 12. Each axially inner anchor stiffening element 53 comprises a first portion 533 extending in the toroidal cavity 35 between a first radially inner anchor point 55A at which each axially inner anchor stiffening element 53 passes through the internal surface 33 to be anchored around the first radially inner reinforcing structure 60A and a first radially outer anchor point 57A at which each axially inner anchor stiffening element 53 passes through the internal surface 33 to be anchored in the first and second radially outer reinforcing structures 70A, 70B. Each axially inner anchor stiffening element 53 comprises a second portion 534 extending in the toroidal cavity 35 between a second radially inner anchor point 55B at which each axially inner anchor stiffening element 53 passes through the internal surface 33 to be anchored around the second radially inner reinforcing structure 60B and a second radially outer anchor point 57B at which each axially inner anchor stiffening element 53 passes through the internal surface 33 to be anchored in the first and second radially outer reinforcing structures 70A, 70B.

[0305] In a manner analogous to the first embodiment each of the first and second radially inner anchor points 54A, 55A, 54B, 55B and the first and second radially outer anchor points 56A, 57A, 56B, 57B of each axially inner anchor stiffening element 53 and axially outer anchor stiffening element 52 is arranged so that the portion 533 and the portion 534 do not cross over in the toroidal cavity, the portion 523 and the portion 524 not crossing over in the toroidal cavity, the first radially outer anchor points 56A, 57A and the first radially inner anchor points 54A, 55A are axially on the same side of the median plane of the tyre and the second radially outer anchor points 56B, 57B and second radially inner anchor points 54B, 55B are axially arranged on the same other side of the median plane of the tyre.

[0306] Each of the first and second radially outer anchor points 57A, 57B of each axially inner anchor stiffening element 53 is axially and respectively inside each of the first and second radially outer anchor points 56A, 56B of each axially outer anchor stiffening element 52.

[0307] Each of the first and second radially outer anchor points 57A, 57B, 56A, 56B of each axially inner anchor stiffening element 53 and the axially outer anchor stiffening elements 52 is aligned with one of the ribs, here with each of the ribs 104 and 108.

[0308] It will be noted that each first radially inner anchor point 55A and each first radially inner anchor point 54A are radially and axially aligned with the same circumferential line. In an analogous manner each second radially inner anchor point and each second radially inner anchor point 54B are radially and axially aligned on the same circumferential line.

[0309] It will also be noted that each of the first and second radially inner and outer anchor points 55A, 55B, 57A, 57B is in the same meridian section plane as each of the first and second radially inner anchor points and the first and second radially outer anchor points 54A, 54B, 56A, 56B. In a variant that is not depicted it could equally well be envisaged that each of the first and second radially inner and outer anchor points 55A, 55B, 57A, 57B is in a different meridian section plane than each of the first and second radially inner and outer anchor points 54A, 54B, 56A, 56B.

[0310] In this fourth embodiment each of the first and second radially inner anchor reinforcing structures 60A, 60B of each axially inner anchor stiffening element 53 is each of the first and second radially inner anchor reinforcing structures 60A, 60B of each axially outer anchor stiffening element 52. Moreover, the first and second radially outer anchor reinforcing structures 70A, 70B of each axially inner anchor stiffening element 53 are the radially outer anchor reinforcing structures 70A, 70B of each radially outer anchor stiffening element 52. In a variant, it could be envisaged that they are distinct.

[0311] There has been represented in FIG. 9 a tyre in accordance with a fifth embodiment of the invention. Elements analogous to those of tyres in accordance with the previous embodiments are designated by identical references.

[0312] Unlike the fourth embodiment, the stiffening structure 50 comprises radially and axially outer anchor stiffening elements 52 and radially and axially inner anchor stiffening elements 53. The stiffening structure 50 comprises a first radially outer anchor reinforcing structure 60A of each radially and axially outer anchor stiffening element 52 in the first sidewall 30A and a first radially inner anchor reinforcing structure 61A of each radially and axially inner stiffening element 53 in the first sidewall 30A and distinct from the first radially outer reinforcing structure 60A and the first circumferential reinforcing element 40A. The stiffening structure 50 also comprises a second radially outer anchor reinforcing structure 60B of each radially and axially outer anchor stiffening element 52 in the second sidewall 30B and a second radially inner anchor reinforcing structure 61B of each radially and axially inner anchor stiffening element 53 in the second sidewall 30B and distinct from the second radially outer reinforcing structure 60B and the second circumferential reinforcing element 40B.

[0313] Unlike the fourth embodiment, each of the first and second radially inner anchor points 55A, 55B of each radially and axially inner anchor stiffening element 53 is radially inside each first and second radially inner anchor point 54A, 54B of each radially and axially outer anchor stiffening element 52.

[0314] Just like in the fourth embodiment, each of the first and second radially outer anchor points 57A, 57B, 56A, 56B of each of the radially and axially inner anchor stiffening elements 53 and the radially and axially outer anchor stiffening elements 52 is aligned with one of the ribs, here with each of the ribs 104 and 108.

[0315] It will be noted that each of the first and second radially outer anchor points 57A, 57B and each of the first and second first radially outer anchor points 56A, 56B are axially offset relative to one another. In a variant, it could be envisaged that they are radially and axially aligned with the same circumferential line.

[0316] It will be noted that each of the first and second radially inner reinforcing structures 60A, 60B is distinct from each of the first and second radially inner reinforcing structures 61A, 61B. In this instance each radially inner reinforcing structure 60A, 60B, 61A, 61B comprises a respective filar reinforcing element 62A, 62B, 63A, 63B distinct from and discontinuous with respect to the filar reinforcing element of the other radially inner reinforcing structure in the same sidewall and/or the same bead. In a variant, it could be envisaged that these radially inner reinforcing structures are the same.

[0317] There have been represented in FIGS. 10 to 13 a tyre in accordance with a sixth embodiment of the invention. Elements analogous to those of the tyres in accordance with the previous embodiments are designated by identical references.

[0318] Unlike the previous embodiments, each of the first and second radially inner reinforcing structures 60A, 60B comprises a respective portion 34A1, 34B1 of the carcass reinforcement 34 extending radially in each of the sidewalls 30A, 30B. In this instance each stiffening element 52A, 52B is wound at least in part around a carcass filar reinforcing element 340 of each portion 34A1, 34B1 of the carcass reinforcement 34 extending radially in each of the sidewalls 30A, 30B.

[0319] In an analogous manner each of the first and second radially outer reinforcing structures 70A, 70B comprises a respective portion 34A2, 34B2 of the carcass reinforcement 34 extending axially in the crown 12. In this instance each stiffening element 52B is wound at least in part around a carcass filar reinforcing element 340 of each portion 34A2, 34B2 of the carcass reinforcement 34 extending axially in the crown 12.

[0320] Unlike the previous embodiments, in this sixth embodiment each of the first and second stiffening elements 52A, 52B is anchored in, and not around, each of the first and second radially inner reinforcing structures 60A, 60B and each of the first and second radially outer reinforcing structures 70A, 70B formed by each corresponding portion 34A1, 34B1, 34A2, 34B2 of the carcass reinforcement 34.

[0321] There has been represented in FIG. 14 a tyre in accordance with a seventh embodiment of the invention. Elements analogous to those of the tyres in accordance with the previous embodiments are designated by identical references.

[0322] Unlike the first embodiment, the first and second beads 32A, 32B comprise respective circumferential reinforcing elements 40A1, 40A2 and 40B1, 40B2 enabling anchoring of the carcass reinforcement 34. Each of these circumferential reinforcing elements is a continuous filar reinforcing element comprising a plurality of circumferential turns around the axis of revolution, radially superposed on one another.

[0323] Obviously, embodiments could be envisaged comprising circumferential reinforcing elements identical to those of the seventh embodiment combined with the stiffening structures of the second, third, fourth, fifth and sixth embodiments.

[0324] There has been represented in FIG. 15 a tyre in accordance with an eighth embodiment of the invention. Elements analogous to those of the tyres in accordance with the previous embodiments are designated by identical references.

[0325] The crown reinforcement 16 comprises working layers 24, 26 and wrapping layers 28 comprising undulations. Undulations of this kind are described in particular in the documents WO2018/073546, WO2018/073547, WO2018/073548 and WO2018/224743.

[0326] Comparative Tests

[0327] In order to demonstrate the benefit of the invention with regard to the durability of the stiffening structure the tyre 10 in accordance with the first embodiment and a prior art tyre R as described in WO2020/128225 but with the dimension 275/35R19 have been compared. Each of the tyres 10 and R is mounted on a nominal rim and inflated to a pressure equal to 250 kPa. A test was then conducted analogous to the load/speed performance test described in appendix VII of EEC-UNO Rule No. 30, but under load and speed conditions that were more constraining. There was then noted the number of kilometres travelled before observing the first separation of the stiffening elements. This number of kilometres travelled was referred to a base 100 corresponding to the number of kilometres travelled by the prior art tyre R so that a number of kilometres travelled greater than 100 indicates improvement of the durability of the stiffening structure.

[0328] The test is passed if the tyre is fit for use after a kilometre threshold that each manufacture sets as a function of their specifications, for example between 10000 and 50000 kilometres. The prior art tyre R was tested under the conditions previously described and after a number of kilometres below the fixed kilometre threshold the prior art tyre R was no longer fit for use because of a loss of pressure following deterioration of its structure. To the contrary, the tyre 10 in accordance with the first embodiment crossed the kilometre threshold with no deterioration and was fit for numerous further kilometres.

[0329] The radial stiffness Kzz, axial stiffness Kyy and the cornering stiffness D(z) of the tyre 10 in accordance with the first embodiment and of the tyre R were also compared. These stiffnesses are substantially identical to those of the tyre described in WO2020/128225 with the dimension 275/35R19 and much better than those of a conventional prior art tyre with no stiffening structure.

[0330] In order to demonstrate the benefit of the invention concerning good flattening of the tread, the tyre 10 in accordance with the first embodiment and a control tyre R not conforming to the invention in which each of the first and second radially outer anchor points is aligned with a main circumferential cut-out were compared. The area of contact of each tyre 10 and R with the ground was simulated with each of the tyres 10 and R subjected to a given lateral force F, mounted on a nominal rim, inflated to a pressure equal to 250 kPa and under a load greater than the nominal load so as to simulate a transfer of load equivalent to the transfer of load that would be observed on an outer wheel of a vehicle negotiating a turn. Note that in FIGS. 16 and 17 the number of axial flexing zones is lower for the tyre 10 than for the control tyre R. There have been represented in dashed line in FIGS. 18 and 19 the axial limits of each rib of the tread of the tyre 10 in order to be able to compare the areas of contact with one another. It is seen that each rib of the tread of the tyre 10 has a contact area width significantly greater than that of the corresponding rib of the tyre R. As explained above, the fact that each of the first and second radially outer anchor points is aligned with one of the main circumferential cut-outs leads to the appearance of a plurality of axial flexing zones of the tread and therefore a reduction of the axial width of the ribs in contact with the ground, in particular by virtue of a displacement of the axial edges of each rib radially in the space formed by the main circumferential cut-outs of the tread delimited by the axial edges of each rib.

[0331] There will now be described tooling and a method enabling manufacture of the tyre according to the invention.

[0332] In order to manufacture the tyre 10 in accordance with the first embodiment tooling and a method that will be described hereinafter are used.

[0333] As depicted in FIGS. 20A, 20B and 21A, 21B the tooling comprises a toroidal core 1000 having, around its main axis Z10, a convex outer receiving surface 1000_out and a radially external crown zone 1100 intended to receive the components constituting the crown 12, a first lateral zone 1200 curved toward the main axis Z10 of the core and intended to receive constituent components of the first sidewall 30A and the first bead 32A and a second lateral zone 1300 curved toward the main axis Z10 of the core and intended to receive constituent components of the second sidewall 30B and the second bead 32B.

[0334] As a result, the core 1000 defines a so-called reserved volume that is delimited externally by the receiving surface 1000_out and corresponds to the internal cavity 35. The core 1000 is thus able to occupy, and thus to reserve temporarily during manufacture of the tyre, the volume of which the shape and the dimensions correspond to those of the internal cavity 35, which volume will become the internal cavity 35.

[0335] The core 1000 has a plurality of passages 1500 that extend inside the reserved volume, under the receiving surface 1000_out, and open onto said receiving surface 1000_out so that each of said passages 1500 connects the crown zone 1100 of the receiving surface 1000_out to one of the first and second lateral zones 1200, 1300 in order for the core 10 to be able to receive the stiffening elements 52 in said passages 1500. The grooves 1500 are blind grooves and have a solid bottom 1900 situated under the receiving surface 1000_out in the reserved volume.

[0336] As can be seen in FIG. 21A in particular, the core 1000 comprises an assembly made up of a plurality annular sub-assemblies 2100, 2200, 2300 including: i) a first annular sub-assembly 2100 termed the central crown 2100, which forms a central portion of the crown zone 1100 of the receiving surface 1000_out intended to receive one or more constituent components of the crown 12, ii) a second annular sub-assembly 2200 termed the left ear 2200 containing the grooves 1500 forming the passages intended for the stiffening elements 52 that connect the first sidewall 30A to the crown 12, and iii) a third annular sub-assembly 2300 termed the right ear 2300 containing the grooves 1500 forming the passages intended for the stiffening elements 52 that connect the second sidewall 30B to the crown 12.

[0337] Each of said annular sub-assemblies 2100, 2200, 2300 is angularly divided into sectors 2400, 2500, 2600, 2700, 2800, 2900 in azimuth around the main axis Z10 with alternating so-called key sectors 2400, 2600, 2800 and so-called vault sectors 2500, 2700, 2900 retained and locked in position by the keys 2400, 2600, 2800 and designed to become manoeuvrable after they have been freed by removing the keys 2400, 2600, 2800. The central ring 2100 is divided into a plurality of ring keys 2400 and ring vaults 2500. Both the ear keys 2600, 2800 and the ear vaults 2700, 2900 are preferably made of metal alloy, more preferably aluminium alloy.

[0338] The method for manufacturing the tyre 10 amounts in practice to using tooling as described above. The method comprises a preparation step (S0) during which the tooling is prepared. During said preparation step (S0) the keys 2400 and the vaults 2500 will be assembled to form said central ring, as depicted in FIGS. 21A and 21B, after which there will be fixed onto each of the clearance faces 3200, 3300 a succession of ear keys 2600, 2800 and ear vaults 2700, 2900 to form the ears 2200, 2300.

[0339] The method thereafter comprises a step (S2) of fitting the stiffening elements 52 during which the stiffening element 52 is passed through each passage 1500. To this end, a stiffening element 52 is disposed continuously along a boustrophedon path through the successive passages 1500, here by inserting the continuous stiffening element 52 in the grooves 1500 and causing the continuous stiffening element 52 to emerge above the receiving surface 1000_out in the crown zone 1100 and in the lateral zones 1200, 1300, at the level of the radially inner anchor points 54A, 54B and radially outer anchor points 56A, 56B, as can be seen in FIG. 22. Then, in a step that is not depicted, the method comprises a protection step (S3) during which an anti-penetration device (not depicted) is used which during the mounting step (S4) and the curing step (S5) cooperates with the core 1000 to constitute an obstacle to penetration of the constituent components of the crown 12, the sidewalls 30A, 30B and the beads 32A, 32B into the grooves 1500 in which the stiffening elements 52 are engaged. An anti-penetration device of this kind could comprise elements for filling the grooves 1500 or masking bands or shells placed over the grooves so as to cover the grooves 1500.

[0340] The method then comprises a mounting step (S4) during which there are disposed on the receiving surface 1000_out the constituent components of the crown 12, the sidewalls 30A, 30B and the beads 32A, 32B. Said components comprise bands or layers based on polymer compounds and the filar reinforcing elements enable the various layers of the tyre 10 to be formed.

[0341] The method then comprises a curing step (S5) during which the core 1000 and the preform of the tyre 10 carried by said core 1000 are placed in a curing mould in order to vulcanise the components.

[0342] The method then comprises a step (S6) of extraction from the mould during which the core 1000 of the tyre 10 is disengaged, leaving the stiffening elements 52 in place in the internal cavity 35, as depicted in particular in the sequences of FIGS. 23A to 23F. Said parts are demounted and progressively extracted to free the tyre 10. The step (S6) of extraction from the mould comprises first a first sub-step of removal of the central ring 2100 during which the keys 2400 are removed radially from the central ring, followed by the vaults 2500 of the central ring, in order to free the ears 2200, 2300, so that the configuration is such that the sectors 2600, 2700, 2800, 2900 of the ears 2200, 2300 are accessible from the interior of the tyre 10 as depicted in FIG. 23A, then a second sub-step of extraction of a first ear 2200 during which the keys 2600 of one of the left and right ears are extracted from the internal cavity 35, after which the vaults 2700 of said ear 2200 are extracted from the internal cavity 35, in order to free the corresponding portion of the internal cavity 35 and the stiffening elements 52 that are located in said portion, then a third sub-step of extraction of the other ear 2300 carried out in an analogous manner to the second sub-step. Here the sectors 2600, 2700, 2800, 2900 are effected by means of an axial extraction movement in translation M_A, if the lateral walls of the grooves 1500 are generated in an axial generatrix direction DG_A colinear with the main axis Z10, as depicted in FIG. 23B; said axial extraction movement in translation M_A may be followed by a movement of tilting in pitch M_B about an axis normal to the sagittal meridian plane of the sector 2600, 2700, 2800, 2900 concerned, as depicted in FIGS. 23D, 23E. When the sector 2600, 2700, 2800, 2900 has been disengaged from the stiffening element 52, the extraction sequence may be completed freely from the interior of the tyre 10, for example, as depicted in FIG. 23F, by a radial movement that moves the sector 2600, 2700, 2800, 2900 concerned toward the main axis Z10 so that said sector is completely removed from the tyre 10. When the sectors 2600, 2700 of an ear 2200 have been extracted, or after each of the ears 2200, 2300 has been freed, the anti-penetration device may in turn be extracted. For example, in the case of masking bands, the latter may be extracted by spiral sliding that causes them to enter the space comprised between two successive stiffening elements 52.

[0343] After the preparation step (S0) and before the step (S2) said method comprises a pre-mounting step (S1) during which, as depicted in FIG. 22, the radially inner reinforcing structures 60A, 60B and the radially outer reinforcing structures 70A, 70B are placed on the lateral zones 1200, 1300 and the crown zone 1100 of the receiving surface 1000_out of the core 1000, facing the radially inner anchor points 54A, 54B and the radially outer anchor points 56A, 56B. The loops forming the portions 521, 522 will be found to be captive on the radially inner reinforcing structures 60A, 60B and other adjacent components of the tyre 10 placed on the lateral zones 1200, 1300, while the portions 525 will be found to be captive on the radially outer reinforcing structures 70A, 70B and other adjacent components of the tyre 10. The invention is not limited to the embodiments described above.

[0344] In fact, combining the second embodiment with the fourth and fifth embodiments could indeed be envisaged.

[0345] Without departing from the scope of the invention, there could be envisaged using a cavity noise absorber, for example fixed to the mounting support of the tyre or to the tyre itself so as to reduce the cavity noise of the tyre. Noise absorbers of this kind are described in particular in WO2018046376, WO2013182477, WO2011051203, EP2660075, EP1253025, EP1876038 and EP3406462.