EP3863841A1 - Process for manufacturing a composite body, in particular a vehicle suspension element, having a given shape - Google Patents

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

Info

Publication number
EP3863841A1
EP3863841A1 EP19813622.8A EP19813622A EP3863841A1 EP 3863841 A1 EP3863841 A1 EP 3863841A1 EP 19813622 A EP19813622 A EP 19813622A EP 3863841 A1 EP3863841 A1 EP 3863841A1
Authority
EP
European Patent Office
Prior art keywords
sheath
rope
sheathing material
composite body
elastic sheathing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19813622.8A
Other languages
German (de)
French (fr)
Inventor
Antoine G. GRONIER
Brahim CHEIKH-BELLA
Stéphane E BETRANCOURT
Abderrahman OUAKKA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
S ARA Composite SAS
Original Assignee
S ARA Composite SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by S ARA Composite SAS filed Critical S ARA Composite SAS
Publication of EP3863841A1 publication Critical patent/EP3863841A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/542—Placing or positioning the reinforcement in a covering or packaging element before or during moulding, e.g. drawing in a sleeve
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/02—Bending or folding
    • B29C53/12—Bending or folding helically, e.g. for making springs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/80—Component parts, details or accessories; Auxiliary operations
    • B29C53/82—Cores or mandrels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/06—Fibrous reinforcements only
    • B29C70/10—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres
    • B29C70/16—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of substantial or continuous length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F1/00—Springs
    • F16F1/36—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers
    • F16F1/366—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers made of fibre-reinforced plastics, i.e. characterised by their special construction from such materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/80—Component parts, details or accessories; Auxiliary operations
    • B29C53/84—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C63/00—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor
    • B29C63/02—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor using sheet or web-like material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
    • B29L2031/3055—Cars
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/774—Springs
    • B29L2031/7742—Springs helical springs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F1/00—Springs
    • F16F1/36—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers
    • F16F1/366—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers made of fibre-reinforced plastics, i.e. characterised by their special construction from such materials
    • F16F1/3665—Wound springs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F2226/00—Manufacturing; Treatments

Definitions

  • 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.
  • 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.
  • the rope passes through a resin bath after each new fibrous layer is wound.
  • the fibrous ribbons wound around the rope during manufacture are pre-impregnated with resin.
  • 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:
  • 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.
  • the sheathing material is deformable and tends to return to its original shape after extension.
  • 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.
  • 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.
  • 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.
  • the installation step includes applying a thermosetting resin on the rope and making said thermosetting resin harden so as to obtain the sheath.
  • the installation step comprises applying a rubber to the cord and vulcanizing said rubber so as to obtain the sheath.
  • 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.
  • the installation step includes braiding or knitting ribbons comprising said elastic sheathing material around the rope.
  • the installation step comprises fitting the sheath onto the rope or co-extruding the sheath with the rope.
  • the installation step includes fitting the sheath on the rope, and the sheath has an opening along its length.
  • said elastic sheathing material is chosen from the group consisting of natural rubbers, synthetic rubbers, thermoplastic resins, and glass fiber fabrics.
  • said elastic sheathing material is a thermoplastic silicone resin.
  • thermoplastic silicone resin makes it possible to give the sheath a smooth surface and a shiny visual appearance on the surface.
  • 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.
  • said elastic sheathing material is heat shrinkable.
  • heat shrinkable is meant that the elastic sheathing material tends to decrease in size under the effect of a rise in temperature.
  • the sheath tends to compress the cord even more during the cooking 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.
  • the elastic sheathing material of the sheath is maintained in a stretched state during the baking 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.
  • said voltage is applied to the two ends of the sheath.
  • 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.
  • the impregnated composite cord is produced by braiding and / or winding prepreg ribbons.
  • the shaping step includes winding the assembly comprising the rope and the sheath around a core.
  • 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.
  • 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.
  • said given shape is a helix.
  • 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.
  • 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).
  • the rope 51 an impregnated composite rope 51
  • 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.
  • 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.
  • 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.
  • elastic is meant that the sheathing material is deformable and tends to return to its initial shape after extension.
  • the sheath 52 is obtained by depositing and in situ polymerization of a thermosetting resin on the rope 51.
  • 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.
  • 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.
  • the sheath 52 is obtained by deposition and vulcanization in situ of a rubber on the rope 51.
  • 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”).
  • 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:
  • EPDM rubbers ethylene propylene diene monomer rubber
  • NBR rubbers Nirile Butadiene Rubber
  • 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
  • non-woven glass fiber veils also known by the English name “glass veils”
  • woven glass fiber fabrics also known by the English name from “woven glass fabric”
  • the elastic sheathing material is a thermoplastic silicone resin.
  • a thermoplastic silicone resin makes it possible to give the sheath 52 a smooth surface and a glossy visual appearance on the surface.
  • 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.
  • 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.
  • 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.
  • the sheath 52 is obtained by braiding or knitting several ribbons comprising the elastic sheathing material.
  • the installation step 3 comprises braiding or knitting the ribbons around the rope 51, so as to obtain the sheath 52.
  • the sheath 52 is fitted onto or co-extruded with the rope 51.
  • the installation step 3 comprises fitting the sheath 52 onto the rope 51 or co - extrude the sheath 52 with the rope 51.
  • 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.
  • the sheath 52 comprises an elastic sheathing material.
  • 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.
  • the assembly 40 is wound around a core 90, so as to obtain a helical shape.
  • 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.
  • the assembly 40 has the given shape.
  • the supply step 2 is carried out continuously.
  • 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.
  • the supply step 2 and the installation step 3 are carried out continuously.
  • 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.
  • the supply step 2, the installation step 3 and the shaping step 4 are carried out continuously.
  • 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.
  • 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.
  • 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.
  • 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.
  • the sheath 52 tends to compress the cord 51, before and during 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.
  • 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.
  • 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.
  • the core 90 is made of a material capable of liquefying during the cooking step 5.
  • 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.
  • the core 90 is made of a eutectic material.
  • 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.
  • the eutectic material to be chosen from the group consisting of the following mixtures: tin-bismuth, lead-tin-bismuth.
  • 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.
  • the elastic sheathing material it is advantageous for the elastic sheathing material to be heat-shrinkable.
  • 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.
  • 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.
  • the elastic sheathing material of the sheath 52 is maintained in a stretched state at least during the cooking step 5.
  • 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.
  • 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.
  • 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.
  • 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.
  • any means capable of maintaining the elastic sheathing material of the sheath 52 in a stretched state can be used.
  • 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.
  • 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.
  • the sheath 52 can more easily be fitted manually onto 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.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • General Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Ropes Or Cables (AREA)

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

PROCÉDÉ DE FABRICATION D'UN CORPS COMPOSITE, EN PARTICULIER UN ÉLÉMENT POUR SUSPENSION DE VÉHICULE, AYANT UNE FORME  METHOD FOR MANUFACTURING A COMPOSITE BODY, IN PARTICULAR A VEHICLE SUSPENSION ELEMENT, HAVING A SHAPE
DONNÉE  DATA
DOMAINE DE L'INVENTION FIELD OF THE INVENTION
[0001] Le présent exposé concerne un procédé de fabrication d'un corps composite ayant une forme donnée.  The present disclosure relates to a method of manufacturing a composite body having a given shape.
[0002] Un tel procédé est notamment particulièrement utile pour fabriquer un corps composite formant un élément pour suspension de véhicule, tel qu'un ressort pour suspension de véhicule ou une barre stabilisatrice pour suspension de véhicule.  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.
ÉTAT DE LA TECHNIQUE ANTÉRIEURE PRIOR STATE OF THE ART
[0003] L'industrie automobile requiert la fabrication de ressorts de grandes tailles et de fortes raideurs pour la suspension des véhicules routiers. Historiquement, ces ressorts automobiles sont réalisés en métal. Toutefois, depuis quelques années, afin notamment d'obtenir d'importants gains de masse, des développements ont été menés pour produire de tels ressorts en matériaux composites.  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] De tels ressorts composites sont ainsi réalisés à partir d'une corde composite, formée d'une pluralité de couches fibreuses imprégnées de résine, enroulées les unes autour des autres, mise en forme puis solidifiée par polymérisation de la résine. Dans certains procédés, la corde passe dans un bain de résine après l'enroulement de chaque nouvelle couche fibreuse. Dans d'autres procédés plus récents, les rubans fibreux enroulés autour de la corde en cours de fabrication sont pré-imprégnés de résine.  [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.
[0005] Dans les procédés de fabrication décrits ci-dessus, une fois que la corde composite est formée, elle doit nécessairement être déplacée vers un poste de mise en forme puis vers un four de cuisson. Ce déplacement est effectué soit automatiquement, soit manuellement ; dans les deux cas, il existe un risque que la corde composite soit endommagée pendant son déplacement, plus particulièrement si celui-ci est effectué manuellement. [0006] Il existe donc un besoin pour un procédé de fabrication permettant de remédier au moins en partie à cet inconvénient. En outre, il existe toujours un besoin pour un procédé de fabrication qui permettrait d'améliorer les propriétés mécaniques du corps composite obtenu. 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.
PRÉSENTATION DE L'INVENTION PRESENTATION OF THE INVENTION
[0007] Le présent exposé concerne un procédé de fabrication d'un corps composite, en particulier un élément pour suspension de véhicule, le corps composite ayant une forme donnée, le procédé comprenant les étapes suivantes :  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:
- fourniture d'une corde composite imprégnée ;  - supply of an impregnated composite rope;
- installation, autour de la corde, d'une gaine comprenant un matériau de gainage élastique ;  - installation, around the rope, of a sheath comprising an elastic sheathing material;
- mise en forme de l'ensemble comprenant la corde et la gaine, de façon à obtenir ladite forme donnée ; et  - shaping of the assembly comprising the rope and the sheath, so as to obtain said given shape; and
- cuisson de l'ensemble ainsi mis en forme, de façon à durcir la résine de la corde et ainsi obtenir le corps composite.  - baking of the whole thus formed, so as to harden the resin of the rope and thus obtain the composite body.
[0008] La gaine installée autour de la corde tend à protéger la corde pendant les étapes ultérieures du procédé, c'est-à-dire pendant l'étape de mise en forme et l'étape de cuisson, et pendant les éventuels déplacements ou manipulations de la corde entre ces étapes.  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.
[0009] Par « élastique », on entend que le matériau de gainage est déformable et tend à reprendre sa forme initiale après une extension. Ainsi, une fois installée sur la corde, la gaine tend à reprendre la forme initiale qu'elle présentait avant l'étape d'installation. On comprendra que la gaine tend donc à comprimer la corde, avant et pendant l'étape de cuisson. Il en résulte que pendant et après l'étape de cuisson, le réseau de fibres et/ou la matrice réticulée du composite sont moins poreux et plus denses. Ceci induit une amélioration appréciable des propriétés mécaniques du corps composite.  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.
[0010] Après l'étape de cuisson, la gaine peut être laissée en place sur le composite, et donc constituer une protection pour le composite pendant le stockage et le transport du corps composite. Elle peut en outre rester en place sur le composite pendant son utilisation, ce qui peut augmenter la durée de vie du corps composite, en particulier lorsque celui-ci est un élément pour suspension de véhicule. La gaine peut adhérer au composite via la matrice réticulée du composite, ce qui améliore la protection qu'elle procure au composite. 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.
[0011] Dans certains modes de réalisation, l'étape d'installation comprend le fait d'appliquer une résine thermodurcissable sur la corde et le fait de faire durcir ladite résine thermodurcissable de façon à obtenir la gaine.  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.
[0012] Dans certains modes de réalisation, l'étape d'installation comprend le fait d'appliquer un caoutchouc sur la corde et le fait de vulcaniser ledit caoutchouc de façon à obtenir la gaine.  In some embodiments, the installation step comprises applying a rubber to the cord and vulcanizing said rubber so as to obtain the sheath.
[0013] Dans certains modes de réalisation, l'étape d'installation comprend le fait d'enrouler un ou plusieurs films ou un ou plusieurs rubans comprenant ledit matériau de gainage élastique autour de la corde. 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.
[0014] L'étape d'installation peut alors être effectuée à l'aide de modules d'enrubannage (« taping machines » en anglais) connus.  The installation step can then be carried out using known taping machines.
[0015] Dans certains modes de réalisation, l'étape d'installation comprend le fait de tresser ou de tricoter des rubans comprenant ledit matériau de gainage élastique autour de la corde.  In some embodiments, the installation step includes braiding or knitting ribbons comprising said elastic sheathing material around the rope.
[0016] Dans certains modes de réalisation, l'étape d'installation comprend le fait d'emmancher la gaine sur la corde ou de co-extruder la gaine avec la corde.  In some embodiments, the installation step comprises fitting the sheath onto the rope or co-extruding the sheath with the rope.
[0017] Dans certains modes de réalisation, l'étape d'installation comprend le fait d'emmancher la gaine sur la corde, et la gaine présente une ouverture le long de sa longueur.  In some embodiments, the installation step includes fitting the sheath on the rope, and the sheath has an opening along its length.
[0018] Dans certains modes de réalisation, ledit matériau de gainage élastique est choisi dans le groupe constitué par les caoutchoucs naturels, les caoutchoucs synthétiques, les résines thermoplastiques, et les étoffes de fibres de verre. In certain embodiments, said elastic sheathing material is chosen from the group consisting of natural rubbers, synthetic rubbers, thermoplastic resins, and glass fiber fabrics.
[0019] Plus particulièrement, dans certains modes de réalisation, ledit matériau de gainage élastique est une résine thermoplastique de silicones.  More particularly, in certain embodiments, said elastic sheathing material is a thermoplastic silicone resin.
[0020] Une telle résine thermoplastique de silicones permet de conférer à la gaine une surface lisse et un aspect visuel brillant en surface. En outre, la gaine confine la quasi-totalité des fibres de la corde, c'est-à- dire que la quasi-totalité des fibres de la corde est maintenue à l'intérieur de la gaine. Ceci diminue l'usure des fibres pendant l'utilisation du corps composite, ce qui retarde son endommagement et accroît en conséquence sa durée de vie. Un tel gain en durée de vie est particulièrement appréciable dans le cas où le corps composite est un ressort pour suspension de véhicule. 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.
[0021] Dans certains modes de réalisation, ledit matériau de gainage élastique est thermorétractable.  In some embodiments, said elastic sheathing material is heat shrinkable.
[0022] Par « thermorétractable », on entend que le matériau de gainage élastique tend à diminuer de dimension sous l'effet d'une élévation de température.  By "heat shrinkable" is meant that the elastic sheathing material tends to decrease in size under the effect of a rise in temperature.
[0023] De cette manière, la gaine tend à comprimer encore davantage la corde pendant l'étape de cuisson. Il en résulte que pendant et après l'étape de cuisson, le réseau de fibres et/ou la matrice réticulée du corps composite sont encore moins poreux et plus denses. Ceci améliore encore les propriétés mécaniques du corps composite.  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.
[0024] Dans certains modes de réalisation, le matériau de gainage élastique de la gaine est maintenu dans un état étiré pendant l'étape de cuisson.  In some embodiments, the elastic sheathing material of the sheath is maintained in a stretched state during the baking step.
[0025] De cette manière, la gaine tend à comprimer encore davantage la corde pendant l'étape de cuisson, avec les mêmes résultats que mentionné précédemment.  In this way, the sheath tends to compress the cord even more during the cooking step, with the same results as mentioned above.
[0026] Dans certains modes de réalisation, avant l'étape de mise en forme, on applique une tension à au moins une extrémité de la gaine, de façon à étirer le matériau de gainage élastique de la gaine ; ladite tension étant appliquée, on installe des moyens pour maintenir le matériau de gainage élastique dans son état étiré ainsi obtenu ; puis on cesse d'appliquer ladite tension.  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.
[0027] Dans certains modes réalisation, on applique ladite tension aux deux extrémités de la gaine.  In some embodiments, said voltage is applied to the two ends of the sheath.
[0028] Dans certains modes de réalisation, le procédé comprend en outre une étape de préchauffage de la gaine, l'étape de préchauffage étant effectuée avant l'étape de mise en forme.  In some embodiments, the method further comprises a step of preheating the sheath, the preheating step being carried out before the shaping step.
[0029] L'étape de préchauffage comprend typiquement le fait de chauffer la gaine à une température de préchauffage strictement inférieure à la température de cuisson utilisée pendant l'étape de cuisson.  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.
[0030] Le préchauffage de la gaine conduit à une augmentation de température de la corde composite imprégnée qui tend à rendre plus fluide la résine (ou matrice) de la corde composite imprégnée. Ceci tend à faciliter le glissement des fibres de la corde composite imprégnée les unes par rapport aux autres, ce qui facilite notamment la mise en forme de la corde composite imprégnée. 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.
[0031] Dans certains modes de réalisation, la corde composite imprégnée est réalisée par tressage et/ou enroulement de rubans pré- imprégnés. In certain embodiments, the impregnated composite cord is produced by braiding and / or winding prepreg ribbons.
[0032] Dans certains modes de réalisation, l'étape de mise en forme comprend le fait d'enrouler l'ensemble comprenant la corde et la gaine autour d'un noyau.  In some embodiments, the shaping step includes winding the assembly comprising the rope and the sheath around a core.
[0033] Dans certains modes de réalisation, le noyau est réalisé en un matériau apte à se liquéfier pendant l'étape de cuisson, en particulier un matériau eutectique, plus particulièrement un matériau eutectique choisi dans le groupe constitué par les mélanges suivants : étain-bismuth, plomb-étain-bismuth.  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.
[0034] De cette manière, il est possible de récupérer la quasi-totalité du matériau du noyau à l'issue de l'étape de cuisson. En outre, si le matériau est eutectique, sa liquéfaction impose un surcroît de dépense d'énergie relativement modéré. Les mélanges étain-bismuth et plomb- étain-bismuth sont particulièrement avantageux à cet égard.  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.
[0035] Le corps composite peut être tout élément pour suspension de véhicule, tel qu'une barre stabilisatrice, un triangle, une bielle, ou un ressort.  The composite body can be any element for vehicle suspension, such as a stabilizer bar, a triangle, a connecting rod, or a spring.
[0036] Le corps composite peut plus particulièrement être un ressort hélicoïdal pour suspension de véhicule.  The composite body may more particularly be a coil spring for vehicle suspension.
[0037] Dans ce cas, ladite forme donnée est une hélice.  In this case, said given shape is a helix.
[0038] Les caractéristiques et avantages précités, ainsi que d'autres, apparaîtront à la lecture de la description détaillée qui suit, d'exemples de réalisation du procédé de fabrication proposés. Cette description détaillée fait référence aux dessins annexés.  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.
BRÈVE DESCRIPTION DES DESSINS BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Les dessins annexés sont schématiques et visent avant tout à illustrer les principes de l'invention. [0040] Sur ces dessins, d'une figure (FIG) à l'autre, des éléments (ou parties d'élément) identiques sont repérés par les mêmes signes de référence. 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.
La FIG 1 est un diagramme-blocs illustrant les étapes d'un procédé de fabrication conforme au présent exposé.  FIG 1 is a block diagram illustrating the steps of a manufacturing process in accordance with this presentation.
La FIG 2A est une vue en perspective d'un ensemble comprenant une corde composite imprégnée et d'une gaine installée autour de la corde, l'ensemble ayant été mis en forme.  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.
La FIG 2B est une vue en coupe de la FIG 2A selon IIB-IIB.  FIG 2B is a sectional view of FIG 2A according to IIB-IIB.
La FIG 2C est une vue analogue à la FIG 2A expliquant schématiquement comment une tension est appliquée à la gaine installée autour de la corde.  FIG 2C is a view similar to FIG 2A schematically explaining how a voltage is applied to the sheath installed around the rope.
La FIG 2D est une vue analogue à la FIG 2A expliquant schématiquement comment le matériau de gainage élastique de la gaine est maintenu dans un état étiré.  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.
La FIG 2E est une vue analogue à la FIG 2D expliquant schématiquement comment le matériau de gainage élastique de la gaine est maintenu dans un état étiré après l'étape de mise en forme.  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.
La FIG 3 représente l'ensemble de la FIG 2A installé sur un noyau pendant sa mise en forme.  FIG 3 shows the assembly of FIG 2A installed on a core during its shaping.
La FIG 4A est une vue en perspective d'un corps composite obtenu par le procédé de fabrication décrit, le corps composite ayant la même forme que l'ensemble représenté sur la FIG 2A.  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.
La FIG 4B est une vue en coupe de la FIG 4A selon IVB-IVB.  FIG 4B is a sectional view of FIG 4A according to IVB-IVB.
La FIG 5A est une vue en perspective analogue à la FIG 2A, montrant une variante de la gaine.  FIG 5A is a perspective view similar to FIG 2A, showing a variant of the sheath.
La FIG 5B est une vue en coupe de la FIG 5A selon VB-VB.  FIG 5B is a sectional view of FIG 5A along VB-VB.
DESCRIPTION DÉTAILLÉE D'EXEMPLE(S) DE RÉALISATION DETAILED DESCRIPTION OF EMBODIMENT (S)
[0041] Afin de rendre plus concrète l'invention, des exemples de procédés de fabrication sont décrits en détail ci-après, en référence aux dessins annexés. Il est rappelé que l'invention ne se limite pas à ces exemples. 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.
[0042] La FIG 1 est un diagramme-blocs représentant les étapes d'un procédé de fabrication 1 d'un corps composite 60. Le procédé 1 comprend une étape de fourniture 2, une étape d'installation 3, une étape de mise en forme 4, et une étape de cuisson 5 qui sont décrites ci-après plus en détail. 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.
[0043] Le procédé 1 permet de fabriquer un corps composite 60. Le corps composite 60 présente une forme donnée, qui est définie à l'avance en fonction de l'utilisation désirée du corps composite 60.  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.
[0044] Le corps composite 60 peut être un élément de suspension de véhicule tel qu'une barre stabilisatrice, un triangle, ou une bielle. Plus particulièrement, le corps composite 60 peut être un ressort pour suspension de véhicule. Dans l'exemple représenté sur les FIG et décrit ci- dessous, le corps composite 60 est un ressort hélicoïdal pour suspension de véhicule, de sorte que la forme donnée est une hélice. Dans d'autres exemples (non représentés), le corps composite 60 est un ressort non hélicoïdal, tel qu'un ressort à lame.  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.
[0045] Le procédé 1 comprend d'abord une étape de fourniture 2 dans laquelle on fournit une corde composite imprégnée 51 (ci-après simplement désignée par « la corde 51 » par commodité). Par « imprégnée », on entend ici que la corde 51 comprend un renfort fibreux imprégné d'une résine (ou matrice) organique.  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).
[0046] La corde 51 peut être réalisée par tressage et/ou enroulement de rubans pré-imprégnés. Les méthodes permettant de réaliser un tel tressage et/ou enroulement sont bien connues en soi et ne sont donc pas décrites en détail ici. En alternative, la corde 51 peut être produite par imprégnation en ligne, c'est-à-dire que la résine ou matrice organique est apportée pendant le tressage et/ou enroulement des rubans fibreux de la corde 51.  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.
[0047] Dans un exemple, les rubans comprennent un renfort de fibres de verres imprégné d'une résine époxy. Chaque ruban prend par exemple la forme d'une bande de largeur et d'épaisseur constantes. En alternative, certains des rubans ou tous les rubans peuvent être de largeur et/ou d'épaisseur variables.  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.
[0048] Le procédé 1 comprend en outre une étape d'installation 3 dans laquelle on installe, autour de la corde 51, une gaine 52.  The method 1 also comprises an installation step 3 in which a sheath 52 is installed around the rope 51.
[0049] La gaine 52 comprend un matériau de gainage élastique, et peut être constituée du matériau de gainage élastique. Par « élastique », on entend que le matériau de gainage est déformable et tend à reprendre sa forme initiale après une extension. [0050] Selon une variante, la gaine 52 est obtenue par dépôt et polymérisation in situ d'une résine thermodurcissable sur la corde 51. Autrement dit, l'étape d'installation 3 comprend le fait d'appliquer une résine thermodurcissable sur la corde 51 et le fait de faire durcir ladite résine thermodurcissable de façon à obtenir la gaine 52. La résine thermodurcissable peut être appliquée, par exemple, par projection électrostatique ou par co-extrusion. Dans un exemple, la résine thermodurcissable est une résine à base époxy. 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.
[0051] Le durcissement de la résine thermodurcissable peut être obtenu par chauffage, par exemple par projection d'infrarouges, et/ou par projection d'ultraviolets. La projection d'ultraviolets est préférée car elle permet de mieux contrôler le degré de polymérisation de la résine thermodurcissable et/ou d'obtenir une durée de polymérisation plus courte.  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.
[0052] Selon une autre variante, la gaine 52 est obtenue par dépôt et vulcanisation in situ d'un caoutchouc sur la corde 51. Autrement dit, l'étape d'installation 3 comprend le fait d'appliquer un caoutchouc sur la corde 51 et le fait de vulcaniser ledit caoutchouc de façon à obtenir la gaine 52. Le caoutchouc peut être choisi parmi les caoutchoucs naturels, et les caoutchoucs synthétiques, tels que par exemple les caoutchoucs EPDM (« ethylene propylene diene monomer rubber » en anglais, aussi connus sous l'appellation éthylène-propylène-diène monomère), les caoutchoucs NBR (« Nitrile Butadiene Rubber » en anglais, aussi connus sous l'appellation de « caoutchoucs nitrile »), les caoutchoucs IIR (« Isobutylene Isoprene Rubber » en anglais, aussi connus sous l'appellation de « caoutchoucs butyle »). 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").
[0053] Selon encore une autre variante, la gaine 52 est formée par un ou plusieurs éléments qui sont installés sur la corde 51 comme cela sera détaillé plus loin. Le matériau de gainage élastique peut alors être choisi dans le groupe constitué par :  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:
- les caoutchoucs naturels,  - natural rubbers,
- les caoutchoucs synthétiques, tels que par exemple les caoutchoucs EPDM (« ethylene propylene diene monomer rubber » en anglais, aussi connus sous l'appellation éthylène-propylène-diène monomère), les caoutchoucs NBR (« Nitrile Butadiene Rubber » en anglais, aussi connus sous l'appellation de « caoutchoucs nitrile »), les caoutchoucs IIR (« Isobutylene Isoprene Rubber » en anglais, aussi connus sous l'appellation de « caoutchoucs butyle ») ; - 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”);
- les résines thermoplastiques, telles que par exemple les résines de silicones, les polyamides (plus particulièrement le nylon 6,6), ou les fluoropolymères thermoplastiques (plus particulièrement le polytétrafluoroéthylène (PTFE)) ; et  - thermoplastic resins, such as for example silicone resins, polyamides (more particularly nylon 6,6), or thermoplastic fluoropolymers (more particularly polytetrafluoroethylene (PTFE)); and
- les étoffes de fibres de verre, comprenant comme cela est connu les voiles de fibres de verre non-tissées (aussi connus sous le nom anglais de « glass veils ») et les tissus de fibres de verre tissées (aussi connus sous le nom anglais de « woven glass fabric »).  - 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").
[0054] Plus particulièrement, le matériau de gainage élastique est une résine thermoplastique de silicones. Une telle résine thermoplastique de silicones permet de conférer à la gaine 52 une surface lisse et un aspect visuel brillant en surface. En outre, la gaine 52 confine la quasi- totalité des fibres de la corde 51, c'est-à-dire que la quasi-totalité des fibres de la corde 51 est maintenue à l'intérieur de la gaine 52. Ceci diminue l'usure des fibres pendant l'utilisation du corps composite 60, ce qui retarde son endommagement et accroît en conséquence sa durée de vie. Un tel gain en durée de vie est particulièrement appréciable dans le cas où le corps composite 60 est un ressort pour suspension de véhicule.  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.
[0055] Dans un exemple, la gaine 52 est obtenue par enroulement d'un ou plusieurs films ou d'un ou plusieurs rubans comprenant le matériau de gainage élastique autour de la corde 51. Autrement dit, l'étape d'installation 3 comprend le fait d'enrouler le ou les films ou le ou les rubans autour de la corde 51, de façon à obtenir la gaine 52. 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.
[0056] Dans un autre exemple, la gaine 52 est obtenue par tressage ou tricotage de plusieurs rubans comprenant le matériau de gainage élastique. Autrement dit, l'étape d'installation 3 comprend le fait de tresser ou de tricoter les rubans autour de la corde 51, de façon à obtenir la gaine 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.
[0057] Dans encore un autre exemple, la gaine 52 est emmanchée sur ou co-extrudée avec la corde 51. Autrement dit, l'étape d'installation 3 comprend le fait d'emmancher la gaine 52 sur la corde 51 ou de co- extruder la gaine 52 avec la corde 51.  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.
[0058] En tout état de cause, à l'issue de l'étape d'installation 3, la gaine 52 entoure la corde 51 comme représenté schématiquement sur les figures 2A et 2B. La gaine 52 tend alors à protéger la corde 51 pendant les étapes ultérieures du procédé 1 décrites ci-après, et pendant les éventuels déplacements ou manipulations de l'ensemble comprenant la corde 51 et la gaine 52 entre ces étapes. 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.
[0059] En outre, comme mentionné précédemment, la gaine 52 comprend un matériau de gainage élastique. Ainsi, une fois installée sur la corde 51, la gaine 52 tend à reprendre la forme initiale qu'elle présentait avant l'étape d'installation 3. On comprendra que la gaine 52 tend donc à comprimer la corde 51. On comprendra également que l'ensemble 40 comprenant la corde 51 et la gaine 52 peut de ce fait être facilement manipulé comme un tout, sans risque que la gaine 52 ne se décroche de la corde 51. 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.
[0060] Le procédé 1 comprend en outre une étape de mise en forme 4 de l'ensemble 40, de façon à obtenir la forme donnée.  The method 1 further comprises a step of shaping 4 of the assembly 40, so as to obtain the given shape.
[0061] La FIG 3 illustre un exemple d'étape de mise en forme 4 permettant de donner à l'ensemble 40 la forme représentée sur la FIG 2A. Dans cet exemple, après l'étape d'installation 3, on enroule l'ensemble 40 autour d'un noyau 90, de façon à obtenir une forme en hélice. Comme représenté schématiquement sur la FIG 3, le noyau 90 peut comprendre des gorges 91 donnant à l'ensemble 40 sa forme en hélice souhaitée, l'ensemble 40 venant s'enrouler dans les gorges 91 pendant l'étape de mise en forme 4. 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.
[0062] En tout état de cause, à l'issue de l'étape de mise en forme 4, l'ensemble 40 présente la forme donnée.  In any event, at the end of the shaping step 4, the assembly 40 has the given shape.
[0063] Dans une variante, l'étape de fourniture 2 est effectuée en continu. Autrement dit, la corde 51 est fournie ou produite en continu. L'étape d'installation 3 est alors précédée d'une étape (non représentée) de découpe de la corde 51, de façon à obtenir un segment de corde 51 de dimensions adéquates. 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.
[0064] Dans une autre variante, l'étape de fourniture 2 et l'étape d'installation 3 sont effectuées en continu. Autrement dit, la corde 51 est fournie ou produite en continu, et la gaine 52 est installée en continu sur la corde 51 ainsi fournie ou produite. L'étape de mise en forme 4 est alors précédée d'une étape (non représentée) de découpe de la corde 51 munie de la gaine 52, de façon à obtenir un ensemble 40 de dimensions adéquates. [0065] Dans encore une autre variante, l'étape de fourniture 2, l'étape d'installation 3 et l'étape de mise en forme 4 sont effectuées en continu. Autrement dit, la corde 51 est fournie ou produite en continu, la gaine 52 est installée en continu sur la corde 51 ainsi fournie ou produite, et l'ensemble 40 ainsi obtenu en continu est mis en forme en continu, par exemple autour d'un noyau tel que décrit ci-dessus. L'étape de cuisson 5 est alors précédée d'une étape (non représentée) de découpe de l'ensemble 40 mis en forme en continu (et éventuellement du noyau ayant servi à sa mise en forme), de façon à obtenir un ensemble 40 de dimensions adéquates. 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.
[0066] Le procédé 1 comprend en outre une étape de cuisson 5 de l'ensemble 40. De façon connue, cette étape de cuisson 5 consiste à porter l'ensemble 40 à une température suffisante et pendant un temps suffisant pour durcir la résine de la corde 51. Bien entendu, ladite température est aussi suffisamment basse pour ne pas endommager (par exemple par pyrolyse) la résine de la corde 51 ou le matériau de la gaine 52.  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.
[0067] À l'issue de l'étape de cuisson 5, on obtient le corps composite 60. Comme représenté sur les FIG 4A et 4B, le corps composite 60 comprend une partie structurelle centrale composite 61 issue de la cuisson de la corde 51. Cette partie centrale 61 est entourée de la gaine 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.
[0068] Comme mentionné précédemment, la gaine 52 tend à comprimer la corde 51, avant et pendant l'étape de cuisson 5. Il en résulte que pendant et après l'étape de cuisson 5, le réseau de fibres et/ou la matrice réticulée de la partie centrale 61 sont moins poreux et plus denses. Ceci induit une amélioration appréciable des propriétés mécaniques du corps composite 60, qui est particulièrement intéressante lorsque le corps composite 60 est un élément pour suspension de véhicule, dont on souhaite qu'il présente la masse la plus faible possible.  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.
[0069] Après l'étape de cuisson 5, la gaine 52 est encore en place sur le composite de la partie centrale 61. After the cooking step 5, the sheath 52 is still in place on the composite of the central part 61.
[0070] La gaine 52 peut, si on le souhaite, être retirée par des méthodes mécaniques et/ou chimiques de la partie centrale 61. Toutefois, il est avantageux de plus simplement laisser la gaine 52 en place sur la partie centrale 61, et ce même éventuellement pendant l'utilisation désirée du corps composite 60. Ceci est particulièrement avantageux si le corps composite 60 est un élément pour suspension de véhicule, en particulier un ressort pour suspension de véhicule. De tels éléments sont en effet sujets à diverses agressions extérieures, et en particulier au gravillonnage. Pour de tels éléments, la gaine 51 peut apporter une protection supplémentaire aux agressions extérieures. La gaine 52 peut en outre adhérer au composite de la partie centrale 61, via la matrice réticulée, ce qui améliore la protection qu'elle procure au composite. 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.
[0071] Dans le cas où l'ensemble 40 a été mis en forme à l'aide du noyau 90 décrit ci-dessus, l'ensemble 40 peut être soumis à l'étape de cuisson 5 ensemble avec le noyau 90, c'est-à-dire que l'on ne retire pas l'ensemble 40 du noyau 90 avant l'étape de cuisson 5. Dans ce cas, il est avantageux que le noyau 90 soit réalisé en un matériau apte à se liquéfier pendant l'étape de cuisson 5. Par « apte à se liquéfier », on entend englober aussi bien les matériaux qui deviennent liquides par fusion sous l'effet de la température appliquée pendant l'étape de cuisson 5 que les matériaux qui deviennent pâteux. Ainsi, il n'est pas nécessaire de retirer mécaniquement l'ensemble 40 du noyau 90, puisque le noyau 90 se liquéfie tout simplement pendant l'étape de cuisson 5.  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.
[0072] Il est encore plus avantageux que le noyau 90 soit réalisé en un matériau eutectique. De tels matériaux présentent en effet des températures de fusion relativement basses, d'où il résulte que la liquéfaction impose un surcroît de dépense d'énergie relativement modéré à l'étape de cuisson 5. Il est encore plus particulièrement avantageux que le matériau eutectique soit choisi dans le groupe constitué par les mélanges suivants : étain-bismuth, plomb-étain-bismuth. 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.
[0073] Il est avantageux que le procédé 1 comprenne en outre une étape de préchauffage (non représentée) dans laquelle on chauffe la gaine 52 à une température de préchauffage typiquement strictement inférieure à la température de cuisson utilisée pendant l'étape de cuisson 5. Cette étape de préchauffage est typiquement réalisée entre l'étape d'installation 3 et l'étape de mise en forme 4.  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.
[0074] Il est avantageux que le matériau de gainage élastique soit thermorétractable. Comme mentionné précédemment, par « thermorétractable », on entend que le matériau de gainage élastique tend à diminuer de dimension sous l'effet d'une élévation de température. Plus concrètement et à titre d'exemple non limitatif, si le matériau de gainage élastique est conformé sous forme de tube, ce tube peut tendre à diminuer de diamètre sous l'effet d'une élévation de température. Cette élévation de température peut être obtenue par l'étape de préchauffage qui vient d'être décrite, la température de préchauffage étant suffisante pour obtenir la dimension de diminution du matériau de gainage élastique tout en restant inférieure à la température de cuisson utilisée pendant l'étape de cuisson 5. 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.
[0075] En tout état de cause, du fait de la diminution de dimension du matériau de gainage, la gaine 52 tend à comprimer encore davantage la corde 51 pendant l'étape de cuisson 5. Il en résulte que pendant et après l'étape de cuisson 5, le réseau de fibres et/ou la matrice réticulée de la partie centrale 61 sont moins poreux et plus denses. Ceci améliore encore les propriétés mécaniques du corps composite 60.  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.
[0076] Avantageusement, le matériau de gainage élastique de la gaine 52 est maintenu dans un état étiré au moins pendant l'étape de cuisson 5. Advantageously, the elastic sheathing material of the sheath 52 is maintained in a stretched state at least during the cooking step 5.
[0077] Par « état étiré », on entend désigner ici un état du matériau de gainage élastique que l'on obtient en étirant le matériau de gainage élastique à partir de son état au repos. Par « maintenu dans un état étiré », on entend que le matériau de gainage élastique est maintenu dans l'état étiré, plutôt que de revenir à son état au repos du fait de ses propriétés élastiques.  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.
[0078] De cette manière, pendant l'étape de cuisson 5, la gaine 52 tend à comprimer encore davantage la corde 51, avec les mêmes résultats que mentionné précédemment. Il est bien entendu que ce résultat est obtenu dès lors que le matériau de gainage élastique est non-auxétique, c'est-à-dire dès lors qu'il présente un coefficient de Poisson strictement positif, de sorte qu'il se contracte effectivement lorsqu'on applique une tension à au moins une de ses extrémités.  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.
[0079] La FIG 2C représente schématiquement un exemple dans lequel on applique une tension aux deux extrémités de la gaine 52. Plus concrètement, à l'aide d'un moyen de sollicitation mécanique approprié, on applique une tension de sollicitation Tl à une première extrémité 52A de la gaine 52, et une tension de sollicitation T2 la deuxième extrémité 52B, opposée à l'extrémité 52A, de la gaine 52. Les tensions de sollicitation Tl et T2 sont en sens contraire comme indiqué par les flèches sur la FIG 2C. On comprendra ainsi en se référant aux FIG 2C et 2B que la gaine 52 tend à comprimer la corde 51 pendant l'étape de cuisson 5. Les tensions de sollicitation Tl et T2 peuvent être appliquées par tout moyen de sollicitation mécanique approprié. 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.
[0080] La FIG 2D représente schématiquement un exemple dans lequel le matériau de gainage élastique de la gaine 52 est maintenu dans un état étiré après l'opération décrite en rapport avec la FIG 2C. Plus concrètement, les tensions de sollicitation Tl et T2 étant toujours appliquées, on installe une première bride 75A à la première extrémité 52A de la gaine 52, et une deuxième bride 75B à la deuxième extrémité 52B de la gaine 52, et on cesse ensuite d'appliquer les tensions de sollicitation Tl et T2 par le moyen de sollicitation mécanique mentionné ci-dessus. L'action des brides 75A et 75B maintient le matériau de gainage élastique de la gaine 52 dans un état étiré, de sorte que la gaine 52 continue à comprimer la corde 51 comme décrit ci-dessus. Il va sans dire qu'au lieu des brides 75A et 75B, on peut utiliser tout moyen apte à maintenir le matériau de gainage élastique de la gaine 52 dans un état étiré.  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.
[0081] Après que les brides 75A et 75B ont été installées, on procède à l'étape de mise en forme 4. On obtient alors l'ensemble 40 mis en forme représenté sur la FIG 2E. Cet ensemble 40 mis en forme est ensuite soumis à l'étape de cuisson 5 comme on l'a décrit précédemment. 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.
[0082] Dans une variante non représentée sur les dessins, on applique une tension à une seule des deux extrémités de la gaine 52, c'est-à-dire qu'on n'applique qu'une seule des deux tensions de sollicitation Tl et T2. L'autre extrémité de la gaine 52 est alors maintenue fixe pendant qu'on applique cette tension de sollicitation Tl ou T2, ce qui évite notamment que la gaine 52 puisse glisser sur la corde 51 avant l'étape de mise en forme 4. 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.
[0083] Les FIG 5A et 5B représentent schématiquement une variante applicable dans le cas où la gaine 52 est emmanchée sur la corde 51 pendant l'étape d'installation 3.  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.
[0084] Dans cette variante, la gaine 52 présente une ouverture 53 s'étendant le long de sa longueur. La gaine 52 peut ainsi présenter une section transversale sensiblement en forme de « U », comme représenté sur la FIG 5B. La présence d'une telle ouverture 53 peut permettre de faciliter l'emmanchement de la gaine 52 sur la corde 51. Notamment, la gaine 52 peut plus facilement être emmanchée manuellement sur la corde 51. 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.
[0085] Après que la gaine 52 a été emmanchée sur la corde 51, les deux bords opposés de l'ouverture 53 peuvent être rapprochés l'un de l'autre, et éventuellement être solidarisés ensemble, par exemple à l'aide d'une colle appropriée, avant de procéder à l'étape de mise en forme 4, ou bien entre l'étape de mise en forme 4 et l'étape de cuisson 5. 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.
[0086] Bien que la présente invention ait été décrite en se référant à des exemples de réalisation spécifiques, des modifications peuvent être apportées à ces exemples sans sortir de la portée générale de l'invention telle que définie par les revendications. En particulier, des caractéristiques individuelles des différents modes de réalisation illustrés/mentionnés peuvent être combinées dans des modes de réalisation additionnels. Par conséquent, la description et les dessins doivent être considérés dans un sens illustratif plutôt que restrictif. 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.
[0087] Il est également évident que toutes les caractéristiques décrites en référence à un procédé sont transposables, seules ou en combinaison, à un dispositif, et inversement, toutes les caractéristiques décrites en référence à un dispositif sont transposables, seules ou en combinaison, à un procédé.  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

REVENDICATIONS
1. Procédé (1) de fabrication d'un corps composite (60), en particulier un élément pour suspension de véhicule, le corps composite (60) ayant une forme donnée, le procédé comprenant les étapes suivantes : 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:
- fourniture (2) d'une corde composite imprégnée (51) ;  - supply (2) of an impregnated composite cord (51);
- installation (3), autour de la corde (51), d'une gaine (52) comprenant un matériau de gainage élastique ;  - Installation (3), around the rope (51), of a sheath (52) comprising an elastic sheathing material;
- mise en forme (4) de l'ensemble (40) comprenant la corde (51) et la gaine (52), de façon à obtenir ladite forme donnée ; et  - shaping (4) of the assembly (40) comprising the rope (51) and the sheath (52), so as to obtain said given shape; and
- cuisson (5) de l'ensemble (40) ainsi mis en forme, de façon à durcir la résine de la corde (51) et ainsi obtenir le corps composite (60). 2. Procédé selon la revendication 1, dans lequel l'étape d'installation (3) comprend le fait d'appliquer une résine thermodurcissable sur la corde (51) et le fait de faire durcir ladite résine thermodurcissable de façon à obtenir la gaine (52). 3. Procédé selon la revendication 1, dans lequel l'étape d'installation (3) comprend le fait d'appliquer un caoutchouc sur la corde - 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) et le fait de vulcaniser ledit caoutchouc de façon à obtenir la gaine(51) and vulcanizing said rubber so as to obtain the sheath
(52). 4. Procédé selon la revendication 1, dans lequel l'étape d'installation (3) comprend le fait d'enrouler un ou plusieurs films ou un ou plusieurs rubans comprenant ledit matériau de gainage élastique autour de la corde (51). 5. Procédé selon la revendication 1, dans lequel l'étape d'installation (3) comprend le fait de tresser ou de tricoter des rubans comprenant ledit matériau de gainage élastique autour de la corde (51). (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. Procédé selon la revendication 1, dans lequel l'étape d'installation (3) comprend le fait d'emmancher la gaine (52) sur la corde (51) ou de co-extruder la gaine (52) avec la corde (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. Procédé selon la revendication 6, dans lequel l'étape d'installation (3) comprend le fait d'emmancher la gaine (52) sur la corde (51), et la gaine (52) présente une ouverture (53) s'étendant le long de sa longueur. 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. Procédé selon l'une quelconque des revendications 4 à 7, dans lequel ledit matériau de gainage élastique est choisi dans le groupe constitué par les caoutchoucs naturels, les caoutchoucs synthétiques, les résines thermoplastiques, et les étoffes de fibres de verre. 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. Procédé selon la revendication 8, dans lequel ledit matériau de gainage élastique est une résine thermoplastique de silicones. 10. Procédé selon l'une quelconque des revendications 4 à 9, dans lequel ledit matériau de gainage élastique est thermorétractable. 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. Procédé selon l'une quelconque des revendications 4 à 10, dans lequel le matériau de gainage élastique de la gaine (52) est maintenu dans un état étiré au moins pendant l'étape de cuisson (5). 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. Procédé selon l'une quelconque des revendications 1 à 11, comprenant en outre une étape de préchauffage de la gaine (52), l'étape de préchauffage étant effectuée avant l'étape de mise en forme (4). 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. Procédé selon l'une quelconque des revendications 1 à 12, dans lequel la corde composite imprégnée (51) est réalisée par tressage et/ou enroulement de rubans pré-imprégnés. 14. Procédé selon la revendication 13, dans lequel l'étape de mise en forme comprend le fait d'enrouler l'ensemble (40) comprenant la corde (51) et la gaine (52) autour d'un noyau (90). 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. Procédé selon la revendication 14, dans lequel le noyau (90) est réalisé en un matériau apte à se liquéfier pendant l'étape de cuisson (5), en particulier un matériau eutectique, plus particulièrement un matériau eutectique choisi dans le groupe constitué par les mélanges suivants : étain-bismuth, plomb-étain-bismuth. 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.
EP19813622.8A 2018-10-12 2019-10-11 Process for manufacturing a composite body, in particular a vehicle suspension element, having a given shape Withdrawn EP3863841A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1859476A FR3087148A1 (en) 2018-10-12 2018-10-12 METHOD FOR MANUFACTURING A COMPOSITE BODY, IN PARTICULAR A VEHICLE SUSPENSION ELEMENT, HAVING A GIVEN SHAPE
PCT/FR2019/052425 WO2020074846A1 (en) 2018-10-12 2019-10-11 Process for manufacturing a composite body, in particular a vehicle suspension element, having a given shape

Publications (1)

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EP3863841A1 true EP3863841A1 (en) 2021-08-18

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EP19813621.0A Withdrawn EP3863840A1 (en) 2018-10-12 2019-10-11 Process for manufacturing a composite body, in particular a vehicle suspension element, having a given shape
EP19813622.8A Withdrawn EP3863841A1 (en) 2018-10-12 2019-10-11 Process for manufacturing a composite body, in particular a vehicle suspension element, having a given shape

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Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1117326A (en) * 1954-01-04 1956-05-22 Thomson Houston Comp Francaise Improvements in methods of isolating large conductors
AU417025B2 (en) * 1967-04-10 1971-09-13 Vulcan Australia Limited Method and apparatus for enveloping elongated articles within an impermeable covering
US3560065A (en) * 1968-02-05 1971-02-02 Plas Steel Products Inc Reinforced plastic bearing
JPS5724215A (en) * 1980-07-18 1982-02-08 Kinugawa Rubber Ind Co Ltd Fitting of covering tube
US4991827A (en) * 1986-11-10 1991-02-12 Tayco Developments, Inc. Springs formed of rope pressure-saturated or impregnated with binder
EP0644383A1 (en) * 1993-09-17 1995-03-22 Atag Verwarming B.V. Intergrated unit for use in a heating apparatus
US20020190451A1 (en) * 2001-06-01 2002-12-19 The University Of Akron Fiber-reinforced composite springs
FR2918918A1 (en) * 2007-07-20 2009-01-23 Allevard Rejna Autosuspensions METHOD FOR ANTICORROSIVE TREATMENT OF A WIRE SPRING.
EP2837488A1 (en) * 2013-08-16 2015-02-18 SuperTEX composites GmbH Methode of producing a spring made of composite material

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FR3087148A1 (en) 2020-04-17
EP3863840A1 (en) 2021-08-18
WO2020074845A1 (en) 2020-04-16

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