Assembly for tire including impregnated woven or knitted fabric(s) and a sacrificial holder

Abstract

A tire assembly includes an assemblage formed of first and second impregnated woven or knitted structures, a bearing structure, and at least one sacrificial holder. The first impregnated woven or knitted structure includes a first woven or knitted fabric and a first layer of a first polymeric composition. The second impregnated woven or knitted structure includes a second woven or knitted fabric and a second layer of a second polymeric composition. The bearing structure includes bearing elements connecting the first and second woven or knitted fabrics together. Each sacrificial holder is structured to hold temporarily the first and second impregnated structures in contact with each other, connecting the first and second woven or knitted fabrics together. When the first and second impregnated woven or knitted structures are separated from each other, each sacrificial holder breaks before any breakage of the bearing elements.

Claims

1. A tire assembly comprising an assemblage that includes: a first impregnated woven or knitted structure including a first woven or knitted fabric and a first layer of a first polymeric composition, the first woven or knitted fabric being impregnated, at least in part, with the first polymeric composition; a second impregnated woven or knitted structure including a second woven or knitted fabric and a second layer of a second polymeric composition, the second woven or knitted fabric being impregnated, at least in part, with the second polymeric composition; a bearing structure including bearing elements connecting the first and second woven or knitted fabrics together; and at least one sacrificial holder for temporarily holding the first and second impregnated woven or knitted structures in contact with each other, and connecting the first and second woven or knitted fabrics together, wherein each sacrificial holder is unbroken in the tire assemblage and structured such that, when the first and second impregnated woven or knitted structures are separated from one another during a tire manufacturing process, each sacrificial holder breaks before any breakage of the bearing elements, wherein each sacrificial holder includes a threadlike sacrificial temporary holding element, and wherein each threadlike sacrificial temporary holding element extends along a length thereof in an alternating pattern from the first woven or knitted fabric toward the second woven or knitted fabric and then from the second woven or knitted fabric toward the first woven or knitted fabric.

2. The tire assembly according to claim 1, wherein: the first impregnated woven or knitted structure includes a first external face, the second impregnated woven or knitted structure includes a second external face, the first and second external faces are substantially parallel to each other, and each sacrificial holder is structured to break before any breakage of the bearing elements when the first and second impregnated woven or knitted structures are separated from each other along a direction substantially perpendicular to the first and second external faces.

3. The tire assembly according to claim 1, wherein each threadlike sacrificial temporary holding element is interlaced with each of the first and second woven or knitted fabrics.

4. The tire assembly according to claim 1, wherein each threadlike sacrificial temporary holding element includes: at least one threadlike binding portion for binding the first and second woven or knitted fabrics to each other, and at least one pair of first and second threadlike gripping portions arranged to prolong the at least one threadlike binding portion.

5. The tire assembly according to claim 4, wherein each bearing element is a threadlike bearing element that includes: at least one threadlike bearing portion extending between the first and second woven or knitted fabrics, and at least one pair of first and second threadlike anchor portions for anchoring the threadlike bearing element respectively in the first and second woven or knitted fabrics, prolonging the at least one threadlike bearing portion respectively into the first and second woven or knitted fabrics, wherein each threadlike sacrificial temporary holding element and each bearing element are arranged so that: at breaking of the threadlike sacrificial temporary holding element, a breaking length is achieved for each threadlike binding portion, and a surface breaking force (Fs′) of each threadlike binding portion is less than a surface breaking force (Fs) of each threadlike bearing portion.

6. The tire assembly according to claim 1, wherein each bearing element is a threadlike bearing element.

7. The tire assembly according to claim 6, wherein each threadlike bearing element extends along a length thereof in an alternating pattern from the first woven or knitted fabric towards the second woven or knitted fabric and then from the second woven or knitted fabric towards the first woven or knitted fabric.

8. The tire assembly according to claim 6, wherein each threadlike bearing element is interlaced with each of the first and second woven or knitted fabrics.

9. The tire assembly according to claim 7, wherein each threadlike bearing element includes: at least one threadlike bearing portion extending between the first and second woven or knitted fabrics, and at least one pair of first and second threadlike anchoring portions structured to anchor the threadlike bearing element respectively in the first and second woven or knitted fabrics to prolong the at least one threadlike bearing portion respectively into the first and second woven or knitted fabrics.

10. The tire assembly according to claim 9, wherein: the first woven or knitted fabric is a first woven fabric that includes intertwinings of a first family of threadlike elements, which are substantially parallel to one another, and a second family of threadlike elements, which are substantially parallel to one another, the second woven or knitted fabric is a second woven fabric that includes intertwinings of a first family of threadlike elements, which are substantially parallel to one another, and a second family of threadlike elements, which are substantially parallel to one another, and each of the first and second threadlike anchoring portions is wound, at least in part, around at least one threadlike element of at least one of the first and second families of threadlike elements respectively of each of the first and second woven fabrics.

11. The tire assembly according to claim 1, wherein the first woven or knitted fabric is a first woven fabric that includes intertwinings of a first family of threadlike elements, which are substantially parallel to one another, and a second family of threadlike elements, which are substantially parallel to one another.

12. The tire assembly according to claim 1, wherein the second woven or knitted fabric is a second woven fabric that includes intertwinings of a first family of threadlike elements, which are substantially parallel to one another, and a second family of threadlike elements, which are substantially parallel to one another.

13. The tire assembly according to claim 11, wherein: the first woven fabric extends along a main general direction, and the threadlike elements of at least one of the first and second families extend along a direction forming an angle at least equal to 10° and at most equal to 45° with the main general direction of the first woven fabric.

14. The tire assembly according to claim 12, wherein: the second woven fabric extends along a main general direction, and the threadlike elements of at least one of the first and second families extend along a direction forming an angle at least equal to 10° and at most equal to 45° with the main general direction of the second woven fabric.

15. A tire comprising an assemblage that includes: a first impregnated woven or knitted structure including a first woven or knitted fabric and a first layer of a first polymeric composition, the first woven or knitted fabric being impregnated, at least in part, with the first polymeric composition; a second impregnated woven or knitted structure including a second woven or knitted fabric and a second layer of a second polymeric composition, the second woven or knitted fabric being impregnated, at least in part, with the second polymeric composition; a bearing structure including bearing elements connecting the first and second woven or knitted fabrics together; and at least one sacrificial holder for temporarily holding the first and second impregnated woven or knitted structures in contact with each other, and connecting the first and second woven or knitted fabrics together, wherein each sacrificial holder is unbroken in the tire assemblage and structured such that, when the first and second impregnated woven or knitted structures are separated from one another during a tire manufacturing process, each sacrificial holder breaks before any breakage of the bearing elements, wherein each sacrificial holder includes a threadlike sacrificial temporary holding element, and wherein each threadlike sacrificial temporary holding element extends along a length thereof in an alternating pattern from the first woven or knitted fabric toward the second woven or knitted fabric and then from the second woven or knitted fabric toward the first woven or knitted fabric.

16. The tire according to claim 15, further comprising: a first structure of revolution formed by the first impregnated woven or knitted structure; a second structure of revolution formed by the second impregnated woven or knitted structure arranged radially internal to the first structure of revolution; a crown structure of revolution arranged radially external to the first structure of revolution; an interior annular space delimited by an internal face of the first structure of revolution and an internal face of the second structure of revolution; and two sidewalls connecting together each axial end of the first structure of revolution and each axial end of the second structure of revolution, the two sidewalls delimiting the interior annular space such that the interior annular space forms a closed cavity that can be pressurized by an inflation gas.

17. A fitted assembly comprising: a tire; and a fitting apparatus structured to fit the tire on a vehicle, wherein the tire includes an assemblage that includes: a first impregnated woven or knitted structure including a first woven or knitted fabric and a first layer of a first polymeric composition, the first woven or knitted fabric being impregnated, at least in part, with the first polymeric composition, a second impregnated woven or knitted structure including a second woven or knitted fabric and a second layer of a second polymeric composition, the second woven or knitted fabric being impregnated, at least in part, with the second polymeric composition, a bearing structure including bearing elements connecting the first and second woven or knitted fabrics together, and at least one sacrificial holder for temporarily holding the first and second impregnated woven or knitted structures in contact with each other, and connecting the first and second woven or knitted fabrics together, wherein each sacrificial holder is unbroken in the tire assemblage and structured such that, when the first and second impregnated woven or knitted structures are separated from one another during a tire manufacturing process, each sacrificial holder breaks before any breakage of the bearing elements, wherein each sacrificial holder includes a threadlike sacrificial temporary holding element, and wherein each threadlike sacrificial temporary holding element extends along a length thereof in an alternating pattern from the first woven or knitted fabric toward the second woven or knitted fabric and then from the second woven or knitted fabric toward the first woven or knitted fabric.

18. A process for manufacturing a tire, the process comprising steps of: winding an assembly around a confection cylinder substantially of revolution around an axis of revolution, the assembly including an assemblage that includes: a first impregnated woven or knitted structure including a first woven or knitted fabric and a first layer of a first polymeric composition, the first woven or knitted fabric being impregnated, at least in part, with the first polymeric composition, a second impregnated woven or knitted structure including a second woven or knitted fabric and a second layer of a second polymeric composition, the second woven or knitted fabric being impregnated, at least in part, with the second polymeric composition, a bearing structure including bearing elements connecting the first and second woven or knitted fabrics together, and at least one sacrificial holder for temporarily holding the first and second impregnated woven or knitted structures in contact with each other, and connecting the first and second woven or knitted fabrics together, wherein, when the first and second impregnated woven or knitted structures are separated from one another, each sacrificial holder breaks before any breakage of the bearing elements, wherein each sacrificial holder includes a threadlike sacrificial temporary holding element, and wherein each threadlike sacrificial temporary holding element extends along a length thereof in an alternating pattern from the first woven or knitted fabric toward the second woven or knitted fabric and then from the second woven or knitted fabric toward the first woven or knitted fabric; and moving at least one of the first and second impregnated woven or knitted structures radially with respect to the axis of revolution to separate the first and second impregnated woven or knitted structures from each other so as to break the at least one sacrificial holder.

19. The process according to claim 18, wherein the tire includes: a first structure of revolution formed by the first impregnated woven or knitted structure, a second structure of revolution formed by the second impregnated woven or knitted structure arranged internal to the first structure of revolution, and two sidewalls connecting together each axial end of the first structure of revolution and each axial end of the second structure of revolution, and wherein the process further comprises steps of: forming an interior annular space delimited by an internal face of the first structure of revolution, an internal face of the second structure of revolution, and the two sidewalls, such that the interior annular space forms a closed cavity that can be pressurized by an inflation gas, and opening out the interior annular space so as to break the at least one sacrificial holder.

20. The process according to claim 19, wherein the interior annular space is formed by joining each sidewall to each axial end of the first and second structures of revolution.

21. The process according to claim 19, wherein the interior annular space is opened out by pressurizing the interior annular space using the inflation gas.

22. The process according to claim 19, further comprising a step of, after the interior annular space has been opened out, winding a crown structure of revolution radially external to the first structure of revolution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood on reading the description which will follow, given solely as nonlimiting example and made with reference to the drawings, in which:

(2) FIG. 1 is a view in perspective and in partial section of a tire according to a first embodiment of the invention;

(3) FIG. 2 is a view in circumferential section of the tire of FIG. 1, in the squashed state;

(4) FIG. 3 is a view in meridian section of the tire of FIG. 1;

(5) FIG. 4 is a top view of one of the woven fabrics of an assembly according to the invention;

(6) FIG. 5 is a view in section of the assembly according to the invention of FIG. 4 along a sectional plane P-P;

(7) FIG. 6 is a view of a bearing element of a bearing structure of the tire of FIG. 1;

(8) FIG. 7 is a view in partial meridian section of the tire of FIG. 1 which makes it possible to see a part of the assembly of FIGS. 4 and 5 after manufacture of the tire;

(9) FIG. 8 illustrates comparative standard curves of the change in the load applied as a function of the deflection for the tire of FIG. 1 and a reference tire of the state of the art;

(10) FIG. 9 illustrates comparative standard curves of the change in the cornering stiffness as a function of the load applied for the tire of FIG. 1 and a reference tire of the state of the art;

(11) FIGS. 10A to 10C illustrate the opening out of the assembly according to the invention during the manufacturing process according to the invention;

(12) FIG. 11 is a view analogous to that of FIG. 1 of a tire according to a second embodiment of the invention;

(13) FIG. 12 is a view analogous to that of FIG. 7 of the tire of FIG. 11.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Examples of Tires According to the Invention

(14) A frame of reference X, Y, Z corresponding to the usual respectively axial (along the YY′ direction), radial (along the ZZ′ direction) and circumferential (along the XX′ direction) orientations of a tire has been represented in the figures.

(15) A tire in accordance with a first embodiment of the invention and denoted by the general reference 20 has been represented in FIG. 1. The tire 20 is substantially of revolution around an axis substantially parallel to the axial direction YY′. The tire 20 is in this instance intended for a passenger vehicle. In FIG. 1, the tire 20 is fitted to a fitting means 22, in this instance a wheel rim, thus forming a fitted assembly 23 according to the invention for a vehicle.

(16) The tire 20 comprises an assemblage 24 comprising a first impregnated woven or knitted structure 25 and a second impregnated woven or knitted structure 27. The second impregnated woven or knitted structure 27 is arranged radially on the inside, with respect to the first impregnated woven structure 25. In the case in point, each first and second structure 25, 27 is an impregnated woven structure. In an alternative form, each first and second structure 25, 27 is an impregnated knitted structure.

(17) As illustrated in FIG. 5, the first impregnated woven structure 25 comprises a first woven or knitted fabric 26, in this instance a woven fabric 26, and a first layer 33 of a first polymeric composition 34, the first woven fabric 26 being impregnated, at least in part, with the first polymeric composition 34. The second impregnated woven structure 27 comprises a second woven or knitted fabric 28, in this instance a woven fabric 28, and a second layer 35 of a second polymeric composition 36, the second woven fabric 28 being impregnated, at least in part, with the second polymeric composition 36. In an alternative form, each first and second structure 25, 27 comprises a knitted fabric impregnated, at least in part, respectively with each polymeric composition 34, 36.

(18) In the tire 20, the first woven fabric 26 is arranged radially on the outside, with respect to the second woven fabric 28. Each first and second polymeric composition 34, 36 comprises, for example, an elastomeric composition comprising at least one elastomer, preferably a diene elastomer, for example natural rubber.

(19) Within the tire 20, the first impregnated woven structure 25 forms a first structure of revolution 25′ and the second impregnated woven structure 27 forms a second structure of revolution 27′ arranged radially on the inside of the first structure of revolution 25′.

(20) The assemblage 24 also comprises a bearing structure 30 comprising bearing elements 32 connecting the first and second woven fabrics 26, 28 together. The bearing structure 30 is in this instance formed of a plurality of bearing elements 32.

(21) Furthermore, the tire 20 comprises a crown structure of revolution 55 arranged radially on the outside of the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′. The crown structure of revolution 55 comprises a circumferential reinforcement 54 and a tread 58, as illustrated in FIGS. 1 and 5. The crown structure of revolution 55 comprises a radially interior face 59 and a radially exterior face 60 formed by the exterior face of the tread 58.

(22) The circumferential reinforcement 54 comprises a polymeric composition, for example an elastomeric composition comprising at least one elastomer, preferably a diene elastomer, for example natural rubber, in which several metal or textile reinforcing elements 56, known to a person skilled in the art, are embedded.

(23) The circumferential reinforcement 54 is arranged radially on the outside of the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′ of the tire 20. The tread 58 is intended to come into contact with the ground. The tread 58 is formed of a polymeric composition, for example an elastomeric composition comprising at least one elastomer, preferably a diene elastomer, for example natural rubber. The tread 58 is arranged radially on the outside of the circumferential reinforcement 54.

(24) As illustrated in FIGS. 1 and 5, the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′ of the tire 20, the second impregnated woven structure 27 forming the second, radially interior, structure of revolution 27′ of the tire 20 and the crown structure of revolution 55 exhibit a common axis of revolution, in the case in point the axis of rotation YY′ of the tire 20.

(25) The first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′ of the tire 20 exhibits an internal face 42 and an external face 43 and also two axial ends 44. The internal face 42 is an internal face of the first woven fabric 26 and the external face 43 is an external face of the first layer 33. Within the tire 20, the internal face 42 is arranged radially on the inside of the external face 43 and the external face 43 is in contact with a radially interior face of the crown structure of revolution 55.

(26) The second impregnated woven structure 27 forming the second, radially interior, structure of revolution 27′ of the tire 20 exhibits an internal face 46 and an external face 47 and also two axial ends 48. The internal face 46 is an internal face of the second woven fabric 28 and the external face 47 is an external face of the second layer 35. Within the tire 20, the internal face 46 is arranged radially on the outside of the external face 47.

(27) The two faces 42 and 46 face one another and are substantially parallel to one another. Within the tire 20, each surface 42, 46 describes a cylinder of revolution around the axis YY′ of the tire 20.

(28) With reference to FIG. 1, the tire 20 also comprises two sidewalls 50. Each sidewall 50 connects together each axial end 44 of the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′ of the tire 20 and each axial end 48 of the second impregnated woven structure 27 forming the second, radially interior, structure of revolution 27′ of the tire 20.

(29) The tire 20 also comprises an interior annular space 52 delimited, on the one hand, by each internal face 42 and 46 and, on the other hand, by the two sidewalls 50. The interior annular space 52 forms a closed cavity which can be pressurized by an inflation gas, for example air. The bearing elements 32 are in pairs independent in the interior annular space 52.

(30) In this first embodiment, the assemblage 24 extends axially in continuous fashion between the two sidewalls 50 of the tire 20. The assemblage 24 extends circumferentially over one turn around the axis of revolution YY′ of the tire 20 so as to form an axially continuous assemblage band 51, as illustrated in FIG. 7.

(31) The interior annular space 52 also comprises sacrificial means 62 for temporarily holding the first woven fabric 26 and the second woven fabric 28 with respect to one another represented in the broken state in FIG. 1 and in the unbroken state in FIG. 5 and which will be described in greater detail with reference the following figures. The same sacrificial temporary holding means 62 are represented in the unbroken state in FIGS. 10A and 10B.

(32) In FIGS. 2 and 3, the tire 20 is represented subjected to a nominal radial load Z.sub.N. The tire 20 is in contact with flat ground by a contact surface area A, having a circumferential length X.sub.A. The bearing elements 32, connected to the portion of the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′ of the tire 20 in contact with the ground via the tread, are subjected to buckling in compression, while at least a part of the bearing elements 32, connected to the portion of the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′ of the tire 20 not in contact with the ground, are in tension.

(33) An external face 53 of the first woven fabric 26, before it is placed in the tire 20, has been represented in FIG. 4. The representation of the first layer 33 of polymeric composition 34 has been deliberately omitted for reasons of clarity of the account. An assembly 90 according to the invention has been represented in FIG. 5.

(34) The first woven fabric 26 is a woven fabric comprising intertwinings of a first family of threadlike elements 64, known as warp threadlike elements, and of a second family of threadlike elements 66, known as weft threadlike elements. The warp threadlike elements 64 of the first woven fabric 26 are substantially parallel to one another and extend along a “warp” direction. The weft threadlike elements 66 of the first woven fabric 26 are substantially parallel to one another and extend along a “weft” direction.

(35) The second woven fabric 28 is a woven fabric comprising intertwinings of a first family of threadlike elements 68, known as warp threadlike elements, and of a second family of threadlike elements 70, known as weft threadlike elements. The warp threadlike elements 68 of the second woven fabric 28 are substantially parallel to one another and extend along a “warp” direction. The weft threadlike elements 70 of the second woven fabric 28 are substantially parallel to one another and extend along a “weft” direction.

(36) Within each first and second woven fabric 26, 28, the warp and weft directions form, with one another, an angle ranging from 70° to 90°. In the case in point, the angle is substantially equal to 90°.

(37) The threadlike elements 64, 66, 68, 70 are all substantially identical. Each threadlike element 64, 66, 68, 70 is a textile threadlike element, in this instance made of polyethylene terephthalate (PET). In the case in point, each threadlike element 64, 66, 68, 70 is a spun threadlike element exhibiting a linear density equal to 170 tex and a tenacity equal to 66 cN/tex.

(38) The bearing elements 32 are threadlike bearing elements. Each threadlike bearing element 32 extends alternately from the first woven fabric 26 towards the second woven fabric 28 and from the second woven fabric 28 towards the first woven fabric 26, on moving along the threadlike bearing element 32. In addition, each threadlike bearing element 32 is interlaced with the first woven fabric 26 and the second woven fabric 28. Each threadlike bearing element 32 is a textile threadlike bearing element, in this instance made of polyethylene terephthalate (PET). In the case in point, each bearing element is a spun threadlike element exhibiting a linear density equal to 55 tex and a tenacity equal to 54 cN/tex.

(39) Each threadlike bearing element 32 comprises a threadlike bearing portion 74 extending between the first and second woven fabrics 26, 28, in particular between the internal faces 42 and 46. Each threadlike bearing element 32 comprises first and second threadlike portions 76, 78 for anchoring the threadlike bearing element 32 respectively in the first woven fabric 26 and the second woven fabric 28. Each first and second threadlike anchoring portion 76, 78 prolongs a bearing portion 74 respectively into each first woven fabric 26 and second woven fabric 28. Each first and second threadlike anchoring portion 76, 78 is wound, at least in part, around several threadlike elements of the first families of warp threadlike elements 64, 68 respectively of each first woven fabric 26 and each second woven fabric 28. Thus, each threadlike anchoring portion 76, 78 connects two threadlike bearing portions 74 together.

(40) Each sacrificial temporary holding means 62 comprises a threadlike sacrificial temporary holding element 82. The threadlike sacrificial temporary holding elements 82 are represented in the unbroken state in FIGS. 5, 10A and 10B and in the broken state in FIG. 10C.

(41) In the unbroken state, and as is visible in FIGS. 10A and 10B, each threadlike sacrificial temporary holding element 82 extends alternately from the first woven fabric 26 towards the second woven fabric 28 and from the second woven fabric 28 towards the first woven fabric 26, on moving along the threadlike sacrificial temporary holding element 82. Each threadlike sacrificial temporary holding element 82 is interlaced with the first woven fabric 26 and the second woven fabric 28. Each threadlike sacrificial temporary holding element 82 is a textile threadlike element, in this instance identical to the threadlike bearing elements 32.

(42) In the unbroken state, as is visible in FIGS. 4 and 5, each threadlike sacrificial temporary holding element 82 comprises one or more threadlike portions 84 for binding the first woven fabric 26 and the second woven fabric 28 with respect to one another. Each threadlike sacrificial temporary holding element 82 comprises first and second threadlike gripping portions 86, 88 prolonging the threadlike binding portion 84 respectively into each first and second impregnated woven structure 25, 27, in this instance respectively into each first and second woven fabric 26, 28.

(43) The gripping portions 86 of the threadlike sacrificial temporary holding elements 82 and also the threadlike anchoring portions 76 of the threadlike bearing elements 32 are seen in FIGS. 4 and 7.

(44) In FIG. 4, the first woven fabric 26 and the second woven fabric 28 both extend along a main general direction G substantially parallel to the longitudinal edges of the first and second woven fabrics 26, 28. The warp threadlike elements 64 of the first, radially exterior, woven fabric 26 extend along a direction forming, with the main general direction of the first woven fabric 26, an angle A1 at least equal to 10° and at most equal to 45°. The weft threadlike elements 66 of the first, radially exterior, woven fabric 26 extend along a direction forming, with the main general direction of the first woven fabric 26, an angle A2 at least equal to 10° and at most equal to 45°.

(45) Analogously, the warp threadlike elements 68 of the second, radially interior, woven fabric 28 extend along a direction forming, with the main general direction of the second, radially interior, woven fabric 28, an angle A3 at least equal to 10° and at most equal to 45°. The weft threadlike elements 70 of the second, radially interior, woven fabric 28 extend along a direction forming, with the main general direction of the first woven fabric 26, an angle A4 at least equal to 10° and at most equal to 45°. In the case in point, A1=A2=A3=A4=45°.

(46) A threadlike bearing portion 74 of a threadlike bearing element 32 has been represented in FIG. 6. The threadlike bearing portion 74 exhibits a circular mean section S.sub.P, defined by a characteristic smallest dimension E and a characteristic largest dimension L which are both equal, in the example presented, to the diameter of the circle, and characterized by its aspect ratio K equal to L/E, and thus equal to 1 in the present case. In addition, the characteristic smallest dimension E of the mean section S.sub.P of the threadlike bearing portion 74, that is to say, in the present case, its diameter, is at most equal to 0.02 times the mean radial height H of the interior annular space 52. The bearing portion 74 has a length L.sub.P at least equal to the mean height H of the interior annular space 52. The threadlike anchoring portions 76, 78 exhibit the same circular mean section S.sub.P and the same characteristic smallest dimension E of the mean section S.sub.P.

(47) The tire 20 has been represented partially in FIG. 7 so as to see the external face 53 of the first woven fabric 26 when the latter is arranged within the tire 20.

(48) The warp threadlike elements 64 of the first woven fabric 26 extend along a direction forming, with the circumferential direction XX′ of the tire 20, an angle B1 which is less than the angle A1. Likewise, the weft threadlike elements 66 of the first woven fabric 26 extend along a direction forming, with the circumferential direction XX′ of the tire 20, an angle B2 which is less than the angle A2.

(49) The warp threadlike elements 68 of the second, radially interior, woven fabric 28 extend along a direction forming, with the circumferential direction XX′ of the tire 20, an angle B3. Likewise, the weft threadlike elements 70 of the second, radially interior, woven fabric 28 extend along a direction forming, with the circumferential direction XX′ of the tire 20, an angle B4.

(50) In the case in point, each angle B1, B2 is respectively less than each angle A1, A2 and is at least equal to 10° and less than 45° and in this instance B1=B2=38°. Each angle B3, B4 is respectively substantially equal to each angle A3, A4 and is at least equal to 10° and less than or equal to 45° and in this instance B3=B4=45°.

(51) The tire 20, the stiffness characteristics of which are presented in FIGS. 8 and 9, comprises first and second radially exterior and radially interior structures of revolution 25′, 27′ having respective mean radii equal to 333 mm and 298 mm, and axial widths both equal to 250 mm. The interior annular space 52 has a mean radial height H equal to 35 mm. The tire 20 is inflated to a pressure P of between 1.5 bar and 2.5 bar and is subjected to a radial load Z.sub.N equal to 600 daN.

(52) FIG. 8 presents two comparative standard curves of the change in the load applied Z, expressed in daN, as a function of deflection F, expressed in mm, for a tire according to the invention I and a reference tire R of the state of the art. FIG. 8 shows that, for a given radial load Z, the deflection F of a tire according to the invention I is smaller than that of the reference tire R. In other words, the radial stiffness of the tire according to the invention I is greater than the radial stiffness of the reference tire R.

(53) FIG. 9 presents two comparative standard curves of the change in the cornering stiffness Z.sub.D, expressed in N/°, as a function of the load applied, expressed in N, for a tire according to the invention I and a reference tire R of the state of the art. FIG. 9 shows that, for a given radial load Z, the cornering stiffness Z.sub.D of a tire according to the invention I is greater than that of the reference tire R.

(54) A manufacturing process according to the invention will now be described with reference to FIGS. 10A, 10B and 10C.

(55) The assembly 90 according to the invention has been represented in FIGS. 10A and 10B. The assembly 90 comprises the assemblage 24 and also the sacrificial temporary holding means 62 represented in the unbroken state. The assemblage 24 is a commercial product, for example available from Girmes International GmbH. In a stage of preparation of the assembly 90, the first woven fabric 26 and the second woven fabric 28 are connected to one another by virtue of the means 62, and the means 62 are arranged so as to hold the internal face 42 of the first woven fabric 26 in contact with the internal face 46 of the second woven fabric 28. Then, in a stage of impregnation of the first and second woven fabrics 26, 28, each first and second woven fabric 26, 28 is respectively impregnated with the first and second polymeric compositions 34, 36, so as to form the first and second bands 33, 35 and to constitute the first and second impregnated woven structures 25, 27.

(56) The assembly 90 according to the invention represented in FIG. 10A is then obtained. In FIG. 10A, each threadlike sacrificial temporary holding element 82 is tensed so as to hold the first and second woven fabrics 26, 28 with respect to one another, without, however, wrinkling the assemblage 24 in the main general direction of the first and second woven fabrics 26, 28. Each threadlike binding portion 84 then exhibits a length at rest L0. Each threadlike bearing portion 74 is in a folded or flexed state. Each threadlike sacrificial temporary holding element 82 is arranged so as to break before the bearing elements 32 when the first and second impregnated woven structures 33, 35 are separated from one another.

(57) The threadlike binding portions 84 are arranged according to a mean surface density D′ per unit of surface area of first impregnated woven structure 25, expressed in l/m.sup.2. Each threadlike binding portion 84 exhibits a breaking force Fr′, expressed in N. The surface breaking force Fs′ of the threadlike binding portions 84, and by extension of the threadlike sacrificial temporary holding elements 82, is then defined by Fs′=Fr′.D′. The surface breaking force Fs of the threadlike bearing portions 74, and by extension of the bearing elements 32, is defined by Fs=Fr.D, in which Fr is the breaking force, in N, of each threadlike bearing portion 74 and D is the mean surface density of the threadlike bearing portions 74 per unit of surface area of first impregnated woven structure 25, expressed in l/m.sup.2. The threadlike sacrificial temporary holding elements 82 and the threadlike bearing elements 32 are arranged so that Fs>Fs′.

(58) In the example of the first embodiment, the threadlike bearing elements 32 and the threadlike sacrificial temporary holding elements 82 are individually identical. Each bearing element 32 is made of polyethylene terephthalate (PET) and exhibits a mean section S.sub.P equal to 7*10.sup.−8 m.sup.2 and a breaking stress F.sub.r/S.sub.P equal to 470 MPa. The mean surface density D of the threadlike bearing portions 74 per unit of surface area of the first impregnated woven structure 25 and per unit of surface area of the second impregnated woven structure 27 is equal to 85 000 yarns/m.sup.2. The breaking forces Fr and Fr′ are equal to 33 N. The mean surface density D′ of the threadlike binding portions 84 per unit of surface area of the first impregnated woven structure 25 and per unit of surface area of the second impregnated woven structure 27 is equal to 200 yarns/m.sup.2.

(59) A confection cylinder is available, the diameter of which is equal to that of the fitting means on which the tire 20 is intended to be fitted. The confection cylinder is substantially of revolution around an axis of revolution coaxial with the axis of revolution YY′ of the tire 20. The assembly 90 of FIG. 10A is wound around this confection cylinder. The assembly 90 according to the invention then forms an axially continuous cylindrical winding around the axis of revolution YY′ of the tire 20, the axial width of which is greater than or equal to 50%, preferably greater than or equal to 75%, of the axial width of the tread 58. In this case, the assembly 90 is deposited according to a single cylindrical winding turn. The expression full-width laying is used, since the targeted axial width of the assembly 90 is obtained in a single cylindrical winding turn. The advantage of full-width laying is the manufacturing productivity. On the other hand, full-width laying necessarily implies the existence of at least one overlapping region, or welding region, along the circumferential direction, between the circumferential ends of the assembly 90, in particular at the end of winding. The assembly 90 is laid so that the warp threadlike elements 64, 68 and the weft threadlike elements 66, 70, which are substantially perpendicular to one another, form, with the circumferential direction XX′ of the tire 20, angles A1, A2, A3, A4 substantially equal to 45°.

(60) The interior annular space 52 is then formed. To do this, in the embodiment described, each sidewall 50 is joined to each axial end 44, 48 of the first impregnated woven structure 25 and of the second impregnated woven structure 27, so as to form the interior annular space 52.

(61) At least one of the first and second impregnated woven structures 25, 27, in the case in point solely the first impregnated woven structure 25, is then separated radially, with respect to the axis of revolution of the tire 20. To do this, in the embodiment described, the interior annular space 52 is opened out by pressurization with an inflation gas of the interior annular space 52, for example air. The assembly 90 according to the invention represented in FIG. 10B is then obtained. Each threadlike binding portion 84 then exhibits a length L1>L0. Each threadlike bearing portion 74 is still in a folded or flexed state.

(62) Subsequently, on continuing to radially separate at least one of the first and second impregnated woven structures 25, 27, in the case in point solely the first impregnated woven structure 25, with respect to the axis of revolution YY′ of the tire 20, the sacrificial temporary holding means 84 are broken. To do this, in the embodiment described, the interior annular space 52 is opened out, so as to break the sacrificial temporary holding means 62, still by pressurization with the inflation gas. When the pressure is sufficiently high, the threadlike sacrificial temporary holding elements 82 are broken without breaking the bearing elements 32, and the breaking length BL of each threadlike binding portion 84 is then achieved, BL being such that BL>L1>L0 and BL=L0(1+Eb′), where Eb′ is the elongation at break, expressed in %, of the threadlike binding portion 84. The assembly represented in FIG. 10C is then obtained, in which assembly the sacrificial means 62 are in a broken state and in which assembly each threadlike bearing portion 74 is in a substantially tensed state.

(63) During the radial separation of at least one of the first and second impregnated woven structures 25, 27 with respect to the axis of revolution YY′ of the tire 20, generally known as conformation, the diameter of the first impregnated woven structure 25 forming the first radially exterior structure of revolution 25′ of the tire 20, and thus of the first woven fabric 26, increases, whereas the diameter of the second impregnated woven structure 27 forming the second radially interior structure of revolution 27′ of the tire 20, and thus of the second woven fabric 28, remains substantially constant. The radial distance, with respect to the axis of revolution YY′ of the tire 20, of the first woven fabric 26 significantly increases during the conformation, as well as its circumferential length, and the angles formed by the warp threadlike elements 64 and the weft threadlike elements 66, with the circumferential direction XX′ of the tire 20, which are initially equal to 45°, decrease and become at least equal to 10° and at most equal to 45°, after conformation, in this instance equal to B1=B2=38°. The radial distance, with respect to the axis of revolution YY′ of the tire 20, of the second woven fabric 28 remains substantially constant during the conformation, its circumferential length does not vary substantially and the angles formed by the warp threadlike elements 68 and the weft threadlike elements 70, with the circumferential direction XX′ of the tire 20, which are initially equal to 45°, remain substantially equal to 45°, after conformation; in this instance; B3=B4=45°.

(64) The crown structure of revolution 55 is then wound radially on the outside of the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′.

(65) Subsequently, the interior annular space 52 is depressurized down to ambient atmospheric pressure. The tire 20 is then obtained in the raw state. Finally, the tire 20 is crosslinked, for example by vulcanization, in order to obtain the tire 20 in the cured state.

(66) A tire 20 according to a second embodiment has been represented in FIGS. 11 and 12. The elements analogous to those represented in the preceding figures are denoted by identical references.

(67) Unlike the tire according to the first embodiment, in the tire 20 according to the second embodiment, the assemblage 24 extends axially in a noncontinuous fashion between the two sidewalls 50 of the tire 20. The assemblage 24 extends circumferentially over several turns around the axis of revolution YY′ of the tire 20 so as to form a winding of an axially noncontinuous assemblage strip 92.

(68) Thus, as is illustrated in FIG. 12, the assembly 90 is wound around the axis of the tire 20 so as to form a helical winding of an assemblage strip 92, the axial portions 94 of the strip 92 being axially juxtaposed. Strip is understood to mean an assembly 90 having a limited axial width, at most equal to 30% of the axial width of the tread 58, and with a great length at least equal to twice the circumference of the tread 58, so that the strip to be laid can be stored in the form of a roll. Such a strip is thus unwound in a helix, having as axis of revolution the axis of revolution of the tire 20. The number of helical winding turns of the strip is determined by the total axial width of the targeted helical winding and by the density of bearing elements 32. The laying of the strip can be contiguous, that is to say that the strip portions are in contact in pairs by their axial edges, or non-contiguous, that is to say that the axial edges of the axial strip portions 94 are spaced out by a substantially nonzero space. The advantage of laying in strips is the absence of overlapping regions, or welding regions, in the circumferential direction, between axial strip portions, at the end of winding.

(69) In a design of strip type, the binding surface area S.sub.E of the external face 43 of the first impregnated woven structure 25 forming the first, radially exterior, structure of revolution 25′ of the tire 20 radially exterior woven fabric with the radially interior face 59 of the crown structure of revolution 55 is the sum of the binding surface areas of the juxtaposed strip 92 axial portions 94.

(70) The strip 92 is wound helically around the axis of revolution of the tire 20 so that, before conformation, the warp threadlike elements 64 and the weft threadlike elements 66 of the first woven fabric 26 extend along a direction forming, with the circumferential direction XX′, respectively an angle A1, A2 at least equal to 10° and at most equal to 45°, and so that the warp threadlike elements 68 and the weft threadlike elements 70 of the second, radially interior, woven fabric 28 extend along a direction forming, with the main general direction of the second, radially interior, woven fabric 28, respectively an angle A3, A4 at least equal to 10° and at most equal to 45°. In the case in point, A1=A2=A3=A4=45°.

(71) As in the first embodiment, after conformation, the angles formed by the warp threadlike elements 64 and the weft threadlike elements 66, with the circumferential direction XX′, which are initially equal to 45°, decrease and become at least equal to 10° and at most equal to 45°, after conformation, in this instance equal to B1=B2=38°. The angles formed by the warp threadlike elements 68 and the weft threadlike elements 70, with the circumferential direction XX′, of the tire 20, which are initially equal to 45°, remain substantially equal to 45°.

(72) The invention is not limited to the embodiments described above.

(73) It will be possible to envisage an embodiment in which the sacrificial temporary holding means is other than a threadlike element. For example, it will be possible to envisage for the sacrificial temporary holding means to be an adhesive composition connecting the first and second woven fabrics together by spots of this adhesive composition.

(74) In an alternative form, each threadlike sacrificial temporary holding element might, of course, be different from the threadlike bearing elements. Thus, for example, it might be possible to have threadlike bearing elements made of PET and threadlike sacrificial elements made of cotton.

(75) It will also be possible to imagine for the stage in which the first woven fabric and the second woven fabric are connected to one another by virtue of the sacrificial temporary holding means, and the sacrificial temporary holding means are arranged to hold the internal face of the first woven fabric in contact with the internal face of the second woven fabric, to be carried out after each first and second woven fabric is respectively impregnated with the first and second compositions.

(76) In the example described above, the binding part of each threadlike sacrificial temporary holding element breaks during the separation of the first and second structures 25, 27 from one another. It might also be possible to imagine breaking of the gripping part.