WO2020074846A1

WO2020074846A1 - Process for manufacturing a composite body, in particular a vehicle suspension element, having a given shape

Info

Publication number: WO2020074846A1
Application number: PCT/FR2019/052425
Authority: WO
Inventors: Antoine G. GRONIER; Brahim CHEIKH-BELLA; Stéphane E BETRANCOURT; Abderrahman OUAKKA
Original assignee: S.Ara Composite
Priority date: 2018-10-12
Filing date: 2019-10-11
Publication date: 2020-04-16
Also published as: WO2020074845A1; FR3087148A1; EP3863841A1; EP3863840A1

Abstract

Disclosed is a process (1) for manufacturing a composite body (60), in particular a vehicle suspension element, the composite body (60) having a given shape, the process involving the following steps: providing (2) an impregnated composite cord (51); placing (3), around the cord (51), a sheath (52) comprising an elastic sheathing material; shaping (4) the assembly (40) comprising the cord (51) and the sheath (52) so as to obtain the given shape; and curing (5) the shaped assembly (40) so as to harden the resin of the cord (51) and thus obtain the composite body (60).

Description

METHOD FOR MANUFACTURING A COMPOSITE BODY, IN PARTICULAR A VEHICLE SUSPENSION ELEMENT, HAVING A SHAPE

DATA

FIELD OF THE INVENTION

The present disclosure relates to a method of manufacturing a composite body having a given shape.

Such a method is particularly particularly useful for manufacturing a composite body forming an element for vehicle suspension, such as a spring for vehicle suspension or a stabilizer bar for vehicle suspension.

PRIOR STATE OF THE ART

The automotive industry requires the manufacture of large springs and high stiffness for the suspension of road vehicles. Historically, these automotive springs are made of metal. However, in recent years, in particular in order to obtain significant gains in mass, developments have been carried out to produce such springs in composite materials.

[0004] Such composite springs are thus produced from a composite cord, formed from a plurality of fibrous layers impregnated with resin, wound around one another, shaped and then solidified by polymerization of the resin. In some processes, the rope passes through a resin bath after each new fibrous layer is wound. In other more recent processes, the fibrous ribbons wound around the rope during manufacture are pre-impregnated with resin.

In the manufacturing methods described above, once the composite rope is formed, it must necessarily be moved to a shaping station and then to a baking oven. This movement is carried out either automatically or manually; in both cases, there is a risk that the composite rope will be damaged during its movement, more particularly if it is carried out manually. There is therefore a need for a manufacturing process which makes it possible to at least partially remedy this drawback. In addition, there is still a need for a manufacturing process which would improve the mechanical properties of the composite body obtained.

PRESENTATION OF THE INVENTION

The present disclosure relates to a method of manufacturing a composite body, in particular an element for vehicle suspension, the composite body having a given shape, the method comprising the following steps:

- supply of an impregnated composite rope;

- installation, around the rope, of a sheath comprising an elastic sheathing material;

- shaping of the assembly comprising the rope and the sheath, so as to obtain said given shape; and

- baking of the whole thus formed, so as to harden the resin of the rope and thus obtain the composite body.

The sheath installed around the rope tends to protect the rope during the later stages of the process, that is to say during the shaping step and the cooking step, and during any movements or handling the rope between these steps.

By "elastic" is meant that the sheathing material is deformable and tends to return to its original shape after extension. Thus, once installed on the rope, the sheath tends to resume the initial shape it presented before the installation step. It will be understood that the sheath therefore tends to compress the cord, before and during the cooking step. As a result, during and after the baking step, the fiber network and / or the crosslinked matrix of the composite are less porous and denser. This induces a significant improvement in the mechanical properties of the composite body.

After the baking step, the sheath can be left in place on the composite, and therefore provide protection for the composite during storage and transport of the composite body. It can also remain in place on the composite during its use, which can increase the life of the composite body, in particular when the latter is a vehicle suspension element. The sheath can adhere to the composite via the crosslinked matrix of the composite, which improves the protection it provides to the composite.

In some embodiments, the installation step includes applying a thermosetting resin on the rope and making said thermosetting resin harden so as to obtain the sheath.

In some embodiments, the installation step comprises applying a rubber to the cord and vulcanizing said rubber so as to obtain the sheath.

In some embodiments, the installation step comprises winding one or more films or one or more ribbons comprising said elastic sheathing material around the rope.

The installation step can then be carried out using known taping machines.

In some embodiments, the installation step includes braiding or knitting ribbons comprising said elastic sheathing material around the rope.

In some embodiments, the installation step comprises fitting the sheath onto the rope or co-extruding the sheath with the rope.

In some embodiments, the installation step includes fitting the sheath on the rope, and the sheath has an opening along its length.

In certain embodiments, said elastic sheathing material is chosen from the group consisting of natural rubbers, synthetic rubbers, thermoplastic resins, and glass fiber fabrics.

More particularly, in certain embodiments, said elastic sheathing material is a thermoplastic silicone resin.

Such a thermoplastic silicone resin makes it possible to give the sheath a smooth surface and a shiny visual appearance on the surface. In addition, the sheath confines almost all of the fibers of the rope, that is to say that almost all of the fibers of the rope are held inside the sheath. This decreases the wear of the fibers during the use of the body composite, which delays its damage and consequently increases its service life. Such a gain in service life is particularly appreciable in the case where the composite body is a spring for vehicle suspension.

In some embodiments, said elastic sheathing material is heat shrinkable.

By "heat shrinkable" is meant that the elastic sheathing material tends to decrease in size under the effect of a rise in temperature.

In this way, the sheath tends to compress the cord even more during the cooking step. As a result, during and after the firing step, the fiber network and / or the crosslinked matrix of the composite body are even less porous and denser. This further improves the mechanical properties of the composite body.

In some embodiments, the elastic sheathing material of the sheath is maintained in a stretched state during the baking step.

In this way, the sheath tends to compress the cord even more during the cooking step, with the same results as mentioned above.

In some embodiments, before the shaping step, a voltage is applied to at least one end of the sheath, so as to stretch the elastic sheathing material of the sheath; said tension being applied, means are installed to maintain the elastic sheathing material in its stretched state thus obtained; then we stop applying said voltage.

In some embodiments, said voltage is applied to the two ends of the sheath.

In some embodiments, the method further comprises a step of preheating the sheath, the preheating step being carried out before the shaping step.

The preheating step typically includes the fact of heating the sheath to a preheating temperature strictly below the cooking temperature used during the cooking step.

The preheating of the sheath leads to an increase in temperature of the impregnated composite cord which tends to make more fluid the resin (or matrix) of the impregnated composite cord. This tends to facilitate the sliding of the fibers of the impregnated composite cord with respect to each other, which in particular facilitates the shaping of the impregnated composite cord.

In certain embodiments, the impregnated composite cord is produced by braiding and / or winding prepreg ribbons.

In some embodiments, the shaping step includes winding the assembly comprising the rope and the sheath around a core.

In some embodiments, the core is made of a material capable of liquefying during the cooking step, in particular an eutectic material, more particularly an eutectic material chosen from the group consisting of the following mixtures: tin- bismuth, lead-tin-bismuth.

In this way, it is possible to recover almost all of the core material at the end of the cooking step. In addition, if the material is eutectic, its liquefaction requires a relatively moderate increase in energy expenditure. Tin-bismuth and lead-tin-bismuth mixtures are particularly advantageous in this regard.

The composite body can be any element for vehicle suspension, such as a stabilizer bar, a triangle, a connecting rod, or a spring.

The composite body may more particularly be a coil spring for vehicle suspension.

In this case, said given shape is a helix.

The aforementioned characteristics and advantages, as well as others, will appear on reading the detailed description which follows, of exemplary embodiments of the proposed manufacturing process. This detailed description refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are schematic and aim above all to illustrate the principles of the invention. In these drawings, from one figure (FIG) to another, identical elements (or parts of elements) are identified by the same reference signs.

FIG 1 is a block diagram illustrating the steps of a manufacturing process in accordance with this presentation.

FIG 2A is a perspective view of an assembly comprising an impregnated composite cord and a sheath installed around the cord, the assembly having been shaped.

FIG 2B is a sectional view of FIG 2A according to IIB-IIB.

FIG 2C is a view similar to FIG 2A schematically explaining how a voltage is applied to the sheath installed around the rope.

FIG 2D is a view similar to FIG 2A schematically explaining how the elastic sheathing material of the sheath is maintained in a stretched state.

FIG 2E is a view similar to FIG 2D explaining schematically how the elastic sheathing material of the sheath is maintained in a stretched state after the shaping step.

FIG 3 shows the assembly of FIG 2A installed on a core during its shaping.

FIG 4A is a perspective view of a composite body obtained by the manufacturing process described, the composite body having the same shape as the assembly shown in FIG 2A.

FIG 4B is a sectional view of FIG 4A according to IVB-IVB.

FIG 5A is a perspective view similar to FIG 2A, showing a variant of the sheath.

FIG 5B is a sectional view of FIG 5A along VB-VB.

DETAILED DESCRIPTION OF EMBODIMENT (S)

In order to make the invention more concrete, examples of manufacturing methods are described in detail below, with reference to the accompanying drawings. It is recalled that the invention is not limited to these examples.

FIG 1 is a block diagram representing the steps of a manufacturing method 1 of a composite body 60. The method 1 comprises a supply step 2, an installation step 3, a step forming 4, and a cooking step 5 which are described below in more detail.

Method 1 makes it possible to manufacture a composite body 60. The composite body 60 has a given shape, which is defined in advance according to the desired use of the composite body 60.

The composite body 60 may be a vehicle suspension element such as a stabilizer bar, a triangle, or a connecting rod. More particularly, the composite body 60 may be a spring for vehicle suspension. In the example shown in FIG and described below, the composite body 60 is a helical spring for vehicle suspension, so that the given shape is a helix. In other examples (not shown), the composite body 60 is a non-helical spring, such as a leaf spring.

The method 1 first comprises a supply step 2 in which there is provided an impregnated composite rope 51 (hereinafter simply referred to as "the rope 51" for convenience). By "impregnated" is meant here that the cord 51 comprises a fibrous reinforcement impregnated with an organic resin (or matrix).

The rope 51 can be made by braiding and / or winding prepreg ribbons. The methods for carrying out such braiding and / or winding are well known per se and are therefore not described in detail here. As an alternative, the rope 51 can be produced by in-line impregnation, that is to say that the organic resin or matrix is provided during the braiding and / or winding of the fibrous ribbons of the rope 51.

In one example, the ribbons include a glass fiber reinforcement impregnated with an epoxy resin. Each ribbon takes the form, for example, of a strip of constant width and thickness. Alternatively, some or all of the ribbons may be of variable width and / or thickness.

The method 1 also comprises an installation step 3 in which a sheath 52 is installed around the rope 51.

The sheath 52 comprises an elastic sheathing material, and can be made of the elastic sheathing material. By "elastic" is meant that the sheathing material is deformable and tends to return to its initial shape after extension. Alternatively, the sheath 52 is obtained by depositing and in situ polymerization of a thermosetting resin on the rope 51. In other words, the installation step 3 comprises applying a thermosetting resin on the rope 51 and the fact of hardening said thermosetting resin so as to obtain the sheath 52. The thermosetting resin can be applied, for example, by electrostatic spraying or by co-extrusion. In one example, the thermosetting resin is an epoxy-based resin.

The hardening of the thermosetting resin can be obtained by heating, for example by projection of infrared rays, and / or by projection of ultraviolet rays. The projection of ultraviolet is preferred because it allows better control of the degree of polymerization of the thermosetting resin and / or to obtain a shorter polymerization time.

In another variant, the sheath 52 is obtained by deposition and vulcanization in situ of a rubber on the rope 51. In other words, the installation step 3 comprises the fact of applying a rubber to the rope 51 and vulcanizing said rubber so as to obtain the sheath 52. The rubber can be chosen from natural rubbers, and synthetic rubbers, such as for example EPDM rubbers (“ethylene propylene diene monomer rubber” in English, also known under the name ethylene-propylene-diene monomer), NBR rubbers (“Nitrile Butadiene Rubber” in English, also known as “nitrile rubbers”), IIR rubbers (“Isobutylene Isoprene Rubber” in English, also known as "butyl rubbers").

According to yet another variant, the sheath 52 is formed by one or more elements which are installed on the rope 51 as will be detailed below. The elastic sheathing material can then be chosen from the group consisting of:

- natural rubbers,

- synthetic rubbers, such as for example EPDM rubbers (“ethylene propylene diene monomer rubber” in English, also known under the name ethylene-propylene-diene monomer), NBR rubbers (“Nitrile Butadiene Rubber” in English, also known as "nitrile rubbers"), IIR rubbers (“Isobutylene Isoprene Rubber” in English, also known as “butyl rubbers”);

- thermoplastic resins, such as for example silicone resins, polyamides (more particularly nylon 6,6), or thermoplastic fluoropolymers (more particularly polytetrafluoroethylene (PTFE)); and

- glass fiber fabrics, including as is known non-woven glass fiber veils (also known by the English name "glass veils") and woven glass fiber fabrics (also known by the English name from "woven glass fabric").

More particularly, the elastic sheathing material is a thermoplastic silicone resin. Such a thermoplastic silicone resin makes it possible to give the sheath 52 a smooth surface and a glossy visual appearance on the surface. In addition, the sheath 52 confines almost all of the fibers of the rope 51, that is to say that almost all of the fibers of the rope 51 are held inside the sheath 52. This reduces the wear of the fibers during use of the composite body 60, which delays its damage and consequently increases its service life. Such a gain in service life is particularly appreciable in the case where the composite body 60 is a spring for vehicle suspension.

In one example, the sheath 52 is obtained by winding one or more films or one or more ribbons comprising the elastic sheathing material around the rope 51. In other words, the installation step 3 comprises winding the film or films or the ribbon (s) around the rope 51, so as to obtain the sheath 52.

In another example, the sheath 52 is obtained by braiding or knitting several ribbons comprising the elastic sheathing material. In other words, the installation step 3 comprises braiding or knitting the ribbons around the rope 51, so as to obtain the sheath 52.

In yet another example, the sheath 52 is fitted onto or co-extruded with the rope 51. In other words, the installation step 3 comprises fitting the sheath 52 onto the rope 51 or co - extrude the sheath 52 with the rope 51.

In any event, at the end of the installation step 3, the sheath 52 surrounds the rope 51 as shown diagrammatically on the Figures 2A and 2B. The sheath 52 then tends to protect the rope 51 during the subsequent steps of method 1 described below, and during any movement or manipulation of the assembly comprising the rope 51 and the sheath 52 between these steps.

In addition, as mentioned above, the sheath 52 comprises an elastic sheathing material. Thus, once installed on the rope 51, the sheath 52 tends to resume the initial shape which it had before the installation step 3. It will be understood that the sheath 52 therefore tends to compress the rope 51. It will also be understood that the assembly 40 comprising the rope 51 and the sheath 52 can therefore be easily manipulated as a whole, without the risk that the sheath 52 will come off the rope 51.

The method 1 further comprises a step of shaping 4 of the assembly 40, so as to obtain the given shape.

FIG 3 illustrates an example of shaping step 4 to give the assembly 40 the shape shown in FIG 2A. In this example, after the installation step 3, the assembly 40 is wound around a core 90, so as to obtain a helical shape. As shown diagrammatically in FIG 3, the core 90 may include grooves 91 giving the assembly 40 its desired helical shape, the assembly 40 coming to wind in the grooves 91 during the shaping step 4.

In any event, at the end of the shaping step 4, the assembly 40 has the given shape.

In a variant, the supply step 2 is carried out continuously. In other words, the rope 51 is supplied or produced continuously. The installation step 3 is then preceded by a step (not shown) of cutting the rope 51, so as to obtain a segment of rope 51 of adequate dimensions.

In another variant, the supply step 2 and the installation step 3 are carried out continuously. In other words, the rope 51 is supplied or produced continuously, and the sheath 52 is installed continuously on the rope 51 thus supplied or produced. The shaping step 4 is then preceded by a step (not shown) of cutting the rope 51 provided with the sheath 52, so as to obtain an assembly 40 of adequate dimensions. In yet another variant, the supply step 2, the installation step 3 and the shaping step 4 are carried out continuously. In other words, the rope 51 is supplied or produced continuously, the sheath 52 is installed continuously on the rope 51 thus supplied or produced, and the assembly 40 thus obtained continuously is shaped continuously, for example around a core as described above. The cooking step 5 is then preceded by a step (not shown) of cutting the assembly 40 continuously shaped (and possibly of the core that served to shape it), so as to obtain an assembly 40 of adequate dimensions.

The method 1 further comprises a cooking step 5 of the assembly 40. In known manner, this cooking step 5 consists in bringing the assembly 40 to a sufficient temperature and for a time sufficient to harden the resin. the cord 51. Of course, said temperature is also low enough not to damage (for example by pyrolysis) the resin of the cord 51 or the material of the sheath 52.

At the end of the cooking step 5, the composite body 60 is obtained. As shown in FIGS 4A and 4B, the composite body 60 comprises a central composite structural part 61 resulting from the cooking of the rope 51 This central part 61 is surrounded by the sheath 52.

As mentioned above, the sheath 52 tends to compress the cord 51, before and during the cooking step 5. As a result, during and after the cooking step 5, the fiber network and / or the matrix cross-linked from the central part 61 are less porous and more dense. This induces an appreciable improvement in the mechanical properties of the composite body 60, which is particularly advantageous when the composite body 60 is an element for vehicle suspension, which it is desired to have the lowest possible mass.

After the cooking step 5, the sheath 52 is still in place on the composite of the central part 61.

The sheath 52 can, if desired, be removed by mechanical and / or chemical methods from the central part 61. However, it is advantageous to simply leave the sheath 52 in place on the central part 61, and this even possibly during the desired use of the composite body 60. This is particularly advantageous if the composite body 60 is an element for vehicle suspension, in particular a spring for vehicle suspension. Such elements are indeed subject to various external aggressions, and in particular to graveling. For such elements, the sheath 51 can provide additional protection against external aggressions. The sheath 52 can also adhere to the composite of the central part 61, via the crosslinked matrix, which improves the protection that it provides to the composite.

In the case where the assembly 40 has been shaped using the core 90 described above, the assembly 40 may be subjected to the cooking step 5 together with the core 90, it that is to say that the assembly 40 is not removed from the core 90 before the cooking step 5. In this case, it is advantageous that the core 90 is made of a material capable of liquefying during the cooking step 5. By “capable of liquefying”, is meant to include both the materials which become liquid by melting under the effect of the temperature applied during the cooking step 5 as well as the materials which become pasty. Thus, it is not necessary to mechanically remove the assembly 40 from the core 90, since the core 90 simply liquefies during the cooking step 5.

It is even more advantageous that the core 90 is made of a eutectic material. Such materials in fact have relatively low melting temperatures, which results in liquefaction imposing a relatively moderate increase in energy expenditure in the cooking step 5. It is even more particularly advantageous for the eutectic material to be chosen from the group consisting of the following mixtures: tin-bismuth, lead-tin-bismuth.

It is advantageous that the method 1 also comprises a preheating step (not shown) in which the sheath 52 is heated to a preheating temperature typically strictly lower than the cooking temperature used during the cooking step 5. This preheating step is typically carried out between the installation step 3 and the shaping step 4.

It is advantageous for the elastic sheathing material to be heat-shrinkable. As mentioned previously, by “heat shrinkable”, it is meant that the elastic sheathing material tends to decrease in size under the effect of a rise in temperature. More concretely and by way of nonlimiting example, if the elastic sheathing material is shaped in the form of a tube, this tube may tend to decrease in diameter under the effect of a rise in temperature. This temperature rise can be obtained by the preheating step which has just been described, the preheating temperature being sufficient to obtain the reduction dimension of the elastic sheathing material while remaining below the baking temperature used during the cooking step 5.

In any event, due to the reduction in size of the sheathing material, the sheath 52 tends to compress the cord 51 even more during the cooking step 5. It follows that during and after the step cooking 5, the network of fibers and / or the crosslinked matrix of the central part 61 are less porous and denser. This further improves the mechanical properties of the composite body 60.

Advantageously, the elastic sheathing material of the sheath 52 is maintained in a stretched state at least during the cooking step 5.

By "stretched state" means here a state of the elastic sheathing material which is obtained by stretching the elastic sheathing material from its state at rest. By "maintained in a stretched state" is meant that the elastic sheathing material is kept in the stretched state, rather than returning to its resting state due to its elastic properties.

In this way, during the cooking step 5, the sheath 52 tends to compress the cord 51 even more, with the same results as mentioned above. It is understood that this result is obtained when the elastic sheathing material is non-auxetic, that is to say when it has a strictly positive Poisson's ratio, so that it actually contracts when applying tension to at least one of its ends.

FIG 2C schematically shows an example in which a voltage is applied to the two ends of the sheath 52. More concretely, using an appropriate mechanical stressing means, a stress tension Tl is applied to a first end 52A of the sheath 52, and a stressing voltage T2 the second end 52B, opposite the end 52A, of the sheath 52. The voltages of stress Tl and T2 are in the opposite direction as indicated by the arrows in FIG 2C. It will thus be understood with reference to FIGS 2C and 2B that the sheath 52 tends to compress the cord 51 during the cooking step 5. The stress voltages T1 and T2 can be applied by any suitable mechanical stress means.

FIG 2D schematically shows an example in which the elastic sheathing material of the sheath 52 is maintained in a stretched state after the operation described in connection with FIG 2C. More concretely, the stress voltages Tl and T2 being always applied, a first flange 75A is installed at the first end 52A of the sheath 52, and a second flange 75B at the second end 52B of the sheath 52, and then we stop d 'apply the stress voltages T1 and T2 by the mechanical stress means mentioned above. The action of the flanges 75A and 75B maintains the elastic sheathing material of the sheath 52 in a stretched state, so that the sheath 52 continues to compress the cord 51 as described above. It goes without saying that instead of the flanges 75A and 75B, any means capable of maintaining the elastic sheathing material of the sheath 52 in a stretched state can be used.

After the flanges 75A and 75B have been installed, we proceed to the shaping step 4. We then obtain the set 40 shaped shown in FIG 2E. This shaped assembly 40 is then subjected to the cooking step 5 as described above.

In a variant not shown in the drawings, a voltage is applied to only one of the two ends of the sheath 52, that is to say that only one of the two stress voltages Tl is applied. and T2. The other end of the sheath 52 is then kept fixed while this stressing voltage T1 or T2 is applied, which in particular prevents the sheath 52 from sliding on the rope 51 before the shaping step 4.

FIGS 5A and 5B schematically represent a variant applicable in the case where the sheath 52 is fitted on the rope 51 during the installation step 3.

In this variant, the sheath 52 has an opening 53 extending along its length. The sheath 52 can thus have a cross section substantially in the shape of a "U", as shown in FIG 5B. The presence of such an opening 53 can make it easier to fit the sheath 52 onto the rope 51. In particular, the sheath 52 can more easily be fitted manually onto the rope 51.

After the sheath 52 has been fitted on the rope 51, the two opposite edges of the opening 53 can be brought together, and possibly be joined together, for example using an appropriate glue, before proceeding to the shaping step 4, or else between the shaping step 4 and the baking step 5.

Although the present invention has been described with reference to specific embodiments, modifications can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various illustrated / mentioned embodiments can be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than restrictive sense.

It is also obvious that all the characteristics described with reference to a method can be transposed, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a method.

Claims

1. Method (1) for manufacturing a composite body (60), in particular an element for vehicle suspension, the composite body (60) having a given shape, the method comprising the following steps:

- supply (2) of an impregnated composite cord (51);

- Installation (3), around the rope (51), of a sheath (52) comprising an elastic sheathing material;

- shaping (4) of the assembly (40) comprising the rope (51) and the sheath (52), so as to obtain said given shape; and

- Firing (5) of the assembly (40) thus formed, so as to harden the resin of the rope (51) and thus obtain the composite body (60). 2. Method according to claim 1, in which the installation step (3) comprises the fact of applying a thermosetting resin on the rope (51) and the fact of hardening said thermosetting resin so as to obtain the sheath ( 52). 3. Method according to claim 1, wherein the installation step (3) comprises applying a rubber to the rope

(51) and vulcanizing said rubber so as to obtain the sheath

(52). 4. The method of claim 1, wherein the installation step (3) comprises winding one or more films or one or more ribbons comprising said elastic sheathing material around the rope (51). 5. The method of claim 1, wherein the installation step (3) comprises braiding or knitting ribbons comprising said elastic sheathing material around the rope (51).

6. The method of claim 1, wherein the installation step (3) comprises fitting the sheath (52) on the rope (51) or co-extruding the sheath (52) with the rope ( 51).

7. The method of claim 6, wherein the installation step (3) comprises fitting the sheath (52) on the rope (51), and the sheath (52) has an opening (53) s 'extending along its length.

8. Method according to any one of claims 4 to 7, in which said elastic sheathing material is chosen from the group consisting of natural rubbers, synthetic rubbers, thermoplastic resins, and glass fiber fabrics.

9. The method of claim 8, wherein said elastic sheathing material is a thermoplastic silicone resin. 10. Method according to any one of claims 4 to 9, wherein said elastic sheathing material is heat shrinkable.

11. Method according to any one of claims 4 to 10, in which the elastic sheathing material of the sheath (52) is maintained in a stretched state at least during the cooking step (5).

12. Method according to any one of claims 1 to 11, further comprising a step of preheating the sheath (52), the step of preheating being carried out before the shaping step (4).

13. Method according to any one of claims 1 to 12, wherein the impregnated composite cord (51) is produced by braiding and / or winding of prepreg tapes. 14. The method of claim 13, wherein the shaping step comprises winding the assembly (40) comprising the rope (51) and the sheath (52) around a core (90).

15. The method of claim 14, wherein the core (90) is made of a material capable of liquefying during the cooking step (5), in particular a eutectic material, more particularly a material eutectic chosen from the group consisting of the following mixtures: tin-bismuth, lead-tin-bismuth.