EP3924117A1 - Hybrid forming method and corresponding forming device - Google Patents

Hybrid forming method and corresponding forming device

Info

Publication number
EP3924117A1
EP3924117A1 EP20709285.9A EP20709285A EP3924117A1 EP 3924117 A1 EP3924117 A1 EP 3924117A1 EP 20709285 A EP20709285 A EP 20709285A EP 3924117 A1 EP3924117 A1 EP 3924117A1
Authority
EP
European Patent Office
Prior art keywords
die
blank
punch
tank
sheet
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.)
Pending
Application number
EP20709285.9A
Other languages
German (de)
French (fr)
Inventor
Gilles Avrillaud
Fabrice BEGUET
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.)
Renault SAS
ADM28 SARL
Original Assignee
Renault SAS
ADM28 SARL
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 Renault SAS, ADM28 SARL filed Critical Renault SAS
Publication of EP3924117A1 publication Critical patent/EP3924117A1/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/06—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves
    • B21D26/10—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves generated by evaporation, e.g. of wire, of liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/06—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves
    • B21D26/12—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves initiated by spark discharge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/22—Deep-drawing with devices for holding the edge of the blanks

Definitions

  • the present invention relates to a hybrid method of forming a sheet and a corresponding forming device.
  • the sheet can for example be folded, rolled, stamped, ....
  • the present invention relates here to the formation of a part of complex shape from a sheet by implementing a combination of known methods.
  • electrohydraulic forming As a method of deforming a sheet, electrohydraulic forming is known, which deforms a sheet against a mold by applying dynamic pressure. To this end, an electric discharge is generated between at least two electrodes in a cavity filled with liquid, for example water. An electric arc is then formed between the two electrodes causing a high temperature gradient and vaporization of the liquid. A pressure wave, also commonly called a "shock wave", travels at high speed and presses the sheet against the mold. Electrohydraulic forming is particularly advantageous in comparison with other forming processes since it allows to have a reduced springback and to obtain etching type details and / or sharp angles and / or elongations before break improved on the parts to be formed.
  • the preforming of the part by applying a quasi-static pressure makes it possible to promote the swallowing of the sheet in the mold, therefore to reduce the deformation of the material to be produced by electrohydraulic forming and therefore to reduce the processing time. forming in the case where it is necessary to recharge the high-voltage pulse electric generator between two discharges or to reduce the size of the generator in the case where it is desired to carry out successive discharges without having to wait between discharges for the generator to recharge.
  • Document US2011 / 0088442 relates to a hydromechanical forming tool which may include electro-hydraulic forming chambers in which an electric discharge can be caused by electrodes in order to improve the level of detail that can be achieved in a mold.
  • Document DE 10019594 discloses a method and a device for the hydromechanical deformation of plastically deformable sheets, in particular for producing automobile body parts, in which the sheet is placed between a forming tool and a cushion of liquid and in which under the effect of a static pressure created in the liquid cushion, the sheet is pressed against the forming tool. Simultaneously with the application of static pressure, a shock wave generator disposed in the cushion of liquid is activated to locally create an increased downforce directed towards areas of the sheet.
  • Document US2012 / 103045 shows a system for the electrohydraulic forming of a sheet in an electrohydroforming machine.
  • the present invention therefore aims to provide a method and a corresponding device which makes it possible to produce simply, by implementing electro-hydro-forming, vertical walls.
  • the present invention provides a hybrid process for forming a material blank in which:
  • the material blank is deformed by stamping using at least one punch to obtain a pre-stamped material blank.
  • a cavity is filled with liquid in which there are, on the one hand, said at least one punch and, on the other hand, at least one pair of electrodes,
  • At least one electric discharge is generated between at least one pair of electrodes so as to deform the pre-stamped material blank against the die.
  • This method makes it possible to promote the swallowing of the material in the die while offering the possibility of creating so-called vertical walls using the punch and also to have a high quality of finish of the part thanks to the electro hydroforming.
  • the relative stroke of each punch relative to the die is limited so that the material blank when pushed by the punch (s) does not come into contact of the matrix.
  • the relative stroke of at least one punch relative to the die is such that the material blank when it is pushed by said at least one punch comes into contact with the die.
  • the hybrid process described above may further include a step during which the liquid at contact of the material blank is pressurized so in deforming the pre-stamped material blank.
  • a hydroforming step is then carried out which is preferably carried out after the deformation by the punch and before the electro-hydroforming.
  • the present invention also provides a device for implementing the hybrid training method described above. It thus offers a device for hybrid forming a material blank comprising:
  • a die cooperating with a blank holder the die being movable relative to the blank holder between a position called the open position in which the material blank can be placed between the die and the blank holder and be therefrom withdrawn, and another position called the closed position in which the blank holder cooperates with the die to maintain in a controlled manner the entire edge of a blank of material to be deformed,
  • the tank comprises at least one movable punch relative to an assembly formed by the blank holder and the die in the closed position between a position called the remote position in which the free end of the punch is at a distance from the die and a position called the close position in which the free end of the punch is at a distance from the die less than its distance away in the remote position.
  • the matrix makes it possible to define the final shape of the sheet to be deformed.
  • the punch is designed to be placed in the cavity and to deform the sheet in the direction of the die by coming into contact with said sheet and by deforming it.
  • the assembly formed by the blank holder and the die in the closed position is movable relative to the tank which remains fixed.
  • the tank has a bottom and a peripheral wall, and that the free edge of the peripheral wall forms a punch.
  • the tank and the at least one punch are preferably one piece.
  • the tank has a bottom and a peripheral wall
  • at least one punch is made on a free edge of a wall extending through the tank by dividing the latter into at least two compartments, and that at least one pair of electrodes is located in each of the two compartments.
  • a preferred variant of a device described above provides that the blank holder is fixed on vertical candles, that the die is mounted mobile in translation relative to the blank holder on the side opposite the candles, that the tank has a bottom and a peripheral wall, and that the tank is mounted fixed while the candles are sliding relative to the tank.
  • the candles can be mounted, for example, on hydraulic cushions. These candles can also be formed, for example, by a gas spring, a hydraulic cylinder or the like.
  • FIG. 1 shows a first step of a hybrid method for forming a sheet, the method being implemented with a hybrid forming device
  • FIG. 2 shows a second step of a hybrid sheet metal forming process, the process being implemented with a hybrid forming device
  • FIG. 3 shows a third step of a hybrid sheet forming process, the process being implemented with a hybrid forming device
  • FIG. 4 shows a fourth step of a hybrid sheet forming process, the process being implemented with a hybrid forming device
  • FIG. 5 shows a fifth step of a hybrid sheet forming process, the process being implemented with a hybrid forming device
  • Figure 1 shows a device for forming a blank of material in longitudinal section through a vertical plane. It will be assumed in the remainder of the description that the material blank to be deformed is a sheet 2, made of steel or a steel-based alloy, or else in another metal or metal alloy. Initially ( Figure 1), this sheet 2 is of a given shape, for example flat as shown in Figure 1. A sheet in the shape of a cap, for example, could also be considered.
  • the sheet 2 to be deformed is placed here between a blank holder 4 and a die 6.
  • the blank holder 4 is carried by candles 8 guided in housings made in a lower frame placed on the supposedly horizontal ground and on which a tank 10 is firmly fixed. It is assumed in the remainder of the description that the candles 8 extend vertically and that they support the blank holder 4 which is therefore located above the candles 8. In this way an up / down orientation is defined . It will be maintained throughout the remainder of the present description.
  • the blank holder 4 is arranged here below the sheet 2. It is an annular part having an upper edge 14 adapted to the die 6 and to the shape that the sheet 2 must take after a first deformation (optional preforming operation described below).
  • the blank holder 4 Around the upper edge 14, the blank holder 4 has a peripheral rim 16 serving as a support for compensating devices 18 intended to cooperate with the die 6 in order to control the clamping forces exerted by the die 6 and the clamp. blank 4 on the sheet 2.
  • the blank holder 4 has a cylindrical surface 20, of section adapted to the shape of the tank 10, of vertical axis. As explained below, this cylindrical surface 20 makes it possible to produce a seal between the blank holder 4 and the tank 10.
  • the blank holder 4 also has a lower base 22 which rests on the candles 8.
  • the latter serve to support the blank holder 4. They could also participate in guiding the blank holder 4 relative to the tank 10
  • These candles can be for example gas springs or hydraulic jacks. They can also be rods mounted on hydraulic cushions.
  • external guide means are preferably provided to provide translational guidance of the assembly formed by the blank holder 4, the die 6 and the sheet 2 clamped between these two elements, relative to the tank 10.
  • the die 6 is the main part of the device which determines the final shape of the sheet 2 after deformation.
  • the lower face of the die 6, that is to say that facing the blank holder 4, is intended to give the final shape of the sheet 2 after deformation.
  • the sheet 2 will be pushed against the die 6, more precisely against the underside of the die 6, in order to be plastically deformed and come to conform to the shape of the latter.
  • the lower face of the die 6, which corresponds to the face of the die 6 located opposite, on the one hand, the blank holder 4 and, on the other hand, the tank 10 also comprises an annular zone disposed facing the upper edge 14 of the hold-down 4. The edge of the sheet 2 will be maintained during the forming process between the upper edge of the hold-down 4 and the aforementioned annular zone of the lower face of matrix 6.
  • the die 6 is movable in a vertical translational movement so as to be able to approach and move away from the blank holder 4 which in a first step is intended to remain fixed.
  • the blank holder 4 remaining fixed the die 6 moves between a first position, called the open position, in which the free space between the blank holder 4 and the die 6 is sufficient to introduce a sheet 2 before deformation and to remove it. after deformation, and a second position called the closed position, in which it clamps the peripheral edge of the sheet 2 to be deformed between its annular zone and the upper edge 14 of the blank holder 4.
  • the compensating devices 18 ensure a constant play between the die 6 and the blank holder 4 corresponding to the thickness of the sheet 2, plus or minus an adjustment value.
  • the tank 10 fulfills here, in this preferred embodiment, the dual function of receptacle for containing a liquid (preferably water) and of punch. It is hereinafter called “tank” but could also be called “punch”. As a variant, these two functions could be dissociated, a separate punch being for example associated with a tank.
  • This tank 10 has in the illustrated embodiment a base plate 24 from which extends a peripheral wall 26. The base plate 24 forms the bottom of the tank 10.
  • the peripheral wall 26 extends vertically and defines with the base plate 24 (which extends substantially horizontally) a cavity which can be filled with liquid (generally water).
  • the outer surface of the wall peripheral 26 cooperates with the cylindrical surface 20 of the blank holder to provide a seal, for example using a seal 28, during a vertical translational movement of the blank holder 4 around the wall peripheral 26.
  • Specific means for example guide columns not shown, preferably provide guidance during a translational movement of the blank holder 4 relative to the tank 10. It is noted that the cylindrical surface 20 may come form the upper edge of the cavity defined by the tank 10 and thus extend this cavity according to the relative position of the blank holder 4 with respect to the tank 10.
  • the upper part of the tank 10 as mentioned above at least partially constitutes the upper face of the punch.
  • the free edge (opposite to the base plate 24) of the peripheral wall 26 has a contour of shape adapted to the deformation that one wishes to impose on the sheet 2. This free edge can thus comprise parts projecting and / or recessed.
  • a wall 30, substantially vertical is arranged in the tank 10, inside the peripheral wall 26. This wall 30 starts from the base plate 24 and extends vertically towards the die 6. The free end of the wall 30 forms a head 32 which is machined according to the shape to be given to the sheet 2.
  • the wall 30 preferably divides the interior cavity of the tank into compartments 34.
  • the compartments can be sealed relative to each other but communications (passages) can be provided between them.
  • each compartment 34 or at least in at least some of them, is arranged a pair of electrodes 36 which are supplied for example through the base plate 24 (connections and insulators not shown).
  • HOF stops 38 that is to say, Closed Tool Height stops, which, in a manner known to those skilled in the art, precisely limit the end of travel of the die 6 (and also of the set formed by the blank holder 4 and the sheet 2 driven by the die 6 during its movement).
  • the HOF stops are arranged on a fixed surface such as for example here an upper face of the lower frame carrying the tank 10, around the peripheral wall 26 and are arranged between this base plate 24 and the lower face of the die 6. They could also come to cooperate with the lower base 22 of the blank holder 4.
  • Figure 1 shows the hybrid forming device in a position corresponding to a first step of a forming process.
  • the die 6 is in the open position, that is to say in its position furthest from the blank holder 4 (and from the vessel 10 including the punch 26, 32).
  • the blank holder 4 and the die 6 are then sufficiently spaced from one another to allow in particular the introduction of a sheet 2 between them.
  • Figure 1 illustrates the placement of this sheet 2, this placement being suggested by the arrow 40 on the left of this figure 1.
  • the blank holder 4 is in a high position, that is to say a position in which the blank holder 4 which carries the sheet 2 is positioned such that the upper part of the tank 10 forming the punch cannot come into contact with the sheet 2. Water may already be present in the compartments 34 of the tank 10.
  • the die 6 is arranged above the sheet 2.
  • Figure 2 illustrates a subsequent step.
  • the die 6 is lowered as suggested by an arrow 42.
  • the peripheral edge of the sheet 2 is clamped between the annular zone of the die 6 and the upper edge of the blank holder 4.
  • the clamping force between the die 6 and the blank holder 4 is regulated by the compensating devices 18 which are arranged between the peripheral edge 16 of the blank holder 4 and an edge of the die 6 (also taking into account a compensation of forces which can be carried out at each of the candles 8).
  • the contact zones, on the one hand, between the sheet 2 and the die 6 and, on the other hand, between the sheet 2 and the blank holder 4 are preferably parallel.
  • the clamping of the die 6 on the sheet 2 could be used in order to perform a first preforming of the sheet 2, for example to bend this last and / or to conform its edge. It is thus possible (optionally) to cause a first deformation of the sheet 2.
  • the clamping of the die 6 on the blank holder 4 also makes it possible to guarantee a watertight seal between the sheet 2 and the blank holder 4.
  • a Peripheral ring can also optionally be formed on the sheet 2 between the die 6 and the blank holder 4 to guarantee a good seal between the sheet 2 and the blank holder 4.
  • An elastomeric seal can also fulfill this function of sealing.
  • the purpose of filling with water is to come and fill the cavity so that the liquid comes into contact with the possibly preformed sheet 2. It can be carried out for example by sucking in the air located below the sheet 2. A simultaneous suction of the air above the sheet 2 is also carried out to maintain substantially the same pressure on both sides of the sheet. 2.
  • the air suction between the sheet 2 and the die 6 is preferably maintained throughout the deformation process to prevent the air in this space interfering with the deformation of the sheet 2. As a variant, it is may provide for evacuating the air through evacuation holes located at a high point of the blank holder 4 when the water rises in the cavity.
  • pressurized air can be used to maintain a concavity in the sheet, thus limiting air bubbles beneath it.
  • the blank holder 4 remains during this filling in the same position as in Figure 1.
  • the die 6 continues to descend towards the tank 10, and causes the descent of the blank holder 4 relative to the tank 10-arrow 44.
  • the punch formed by the tank 10, more particularly the upper peripheral edge of the peripheral wall 26 and the head (s) 32 then come into contact with the sheet 2 and deform the latter plastically by stretching. During this movement, the punch exerts a force that pushes the sheet 2 towards the die 6.
  • the sheet 2 held between the blank holder 4 and the die 6 is placed between the punch and the die 6.
  • the punch and / or the tank 10 act as a male part which cooperates with the die 6, a female part which here has a housing for receiving the punch formed by the upper part of the tank 10.
  • the devices compensators 18 act here to regulate the tension at the edge of the sheet 2 and allow, if necessary, a displacement of material from the sheet 2 towards the interior of the system.
  • a second deformation step (the possible preforming mentioned above being the first deformation step) of the sheet 2 is carried out here.
  • This is a stamping step.
  • care is preferably taken, but not necessarily, that the sheet 2 does not come into contact with the die 6 in its central zone, that is to say in the zone located opposite. vis-à-vis the inside of the peripheral wall 26.
  • it is for example possible to provide in certain places a “complete” deformation of the sheet 2 during this stamping operation. This avoids having to provide electrodes to "cover" the entire surface of the sheet 2.
  • FIG. 4 illustrates an advantageous but optional step of the hybrid forming process. It is proposed here to have a virtually static hydroforming step of the sheet 2 during which this sheet 2 still comes close to the die 6 and can locally come into contact with it. This deformation of the sheet 2 is then obtained by putting the water in the tank 10 under pressure, for example by acting on the die 6 (arrow 42). The sheet 2 therefore separates at least locally from the punch formed by the upper part of the tank 10 and takes an intermediate position between the die 6 and the head (s) 32 and the upper edge of the peripheral wall 26 forming the punch.
  • FIG. 5 illustrates a subsequent step in the process for forming the sheet 2.
  • An electro-hydroforming is shown schematically here.
  • a discharge chamber is formed here and completely filled with water. It includes the cavity inside the tank and extends beyond to the deformed sheet 2 and to the seal produced between the tank and the blank holder 4.
  • the pairs of electrodes 36, arranged in said discharge chamber, are then supplied by a strong current from a discharge of capacitors.
  • this electric discharge creates in the liquid (water) contained in the tank 10 and in the contact with sheet 2 (it is important to have a good filling of water in tank 10 so that the water is in contact with sheet 2 for this electro-hydroforming step) an explosion creating a shock wave which propagates towards the sheet 2.
  • the wall (s) 30 and the peripheral wall 26 guide the shock waves and thus act to allow good deformation of the sheet 2 against the die 6.
  • the drawing does not represent the last steps which relate to the withdrawal of the part which was formed from the sheet 2, with the mold opening and the tank lowering to its position illustrated in FIG. 1.
  • the sheet after deformation can have vertical walls (up to the draft angle to be able to separate at the end of the process the sheet formed from the die 6), in other words, the part obtained by deformation of the sheet may have faces which extend substantially perpendicular to the orientation of the sheet before deformation.
  • the sheet is initially in a horizontal plane. After deformation, it can then have almost vertical faces (before the part is withdrawn from the system).
  • the forming process and the hybrid forming device proposed here make it possible to obtain by electro-hydroforming parts with almost vertical walls with a reduced cycle time.
  • the cost price of such parts can thus be limited.
  • the walls in the tank could for example form a honeycomb-type alveolar structure. It is provided in the illustrated embodiment that the peripheral wall of the tank is part of the punch intended to deform the sheet by stamping. This of course depends on the shape that one wishes to give to the sheet.
  • the peripheral wall of the tank is not necessarily part of the punch. Provision could for example be made in FIG. 3 for the blank holder to be flush with the upper edge of the peripheral wall of the tank.

Abstract

Disclosed is a method for hybrid forming of a material blank, in which: - the material blank (2) to be deformed is placed between a die (6) and a blank holder (4); - the material blank (2) is deformed by stamping using at least one punch (26, 32) in order to obtain a pre-stamped material blank (2); - a cavity, in which both the at least one punch (26, 32) having pre-stamped the material blank (2) as well as at least one pair of electrodes (36) are located, is filled with liquid, - the pre-stamped material blank (2) is placed in contact with the liquid of the cavity, and - at least one electrical discharge is generated between at least one pair of electrodes (36) in such a way as to deform the material blank (2) against the die (6). [Fig. 1]

Description

Description Description
Titre : Procédé de formage hybride et dispositif de Title: Hybrid forming process and device for
formage correspondant corresponding forming
[0001] La présente invention concerne un procédé hybride de formage d’une tôle et un dispositif de formage correspondant. [0001] The present invention relates to a hybrid method of forming a sheet and a corresponding forming device.
[0002] Il existe de nombreux procédés de formage d’une tôle pour lui donner une forme plus ou moins complexe. La tôle peut être par exemple pliée, roulée, emboutie, ... . La présente invention concerne ici la formation d’une pièce de forme complexe à partir d’une tôle en mettant en œuvre une combinaison de procédés connus. [0002] There are many methods of forming a sheet to give it a more or less complex shape. The sheet can for example be folded, rolled, stamped, .... The present invention relates here to the formation of a part of complex shape from a sheet by implementing a combination of known methods.
[0003] Comme procédé de déformation d’une tôle, on connaît le formage électrohydraulique qui vient déformer une tôle contre un moule par application d’une pression dynamique. À cet effet, on génère une décharge électrique entre au moins deux électrodes dans une cavité remplie de liquide, par exemple de l’eau. Un arc électrique est alors formé entre les deux électrodes provoquant un gradient de température élevé et la vaporisation du liquide. Une onde de pression, aussi communément appelée « onde de choc », se déplace à grande vitesse et vient plaquer la tôle contre le moule. Le formage électrohydraulique est particulièrement avantageux en comparaison avec les autres procédés de formage puisqu’il permet d’avoir un retour élastique réduit et d’obtenir des détails de type gravure et/ou des angles vifs et/ou des allongements avant rupture améliorés sur les pièces à former. [0003] As a method of deforming a sheet, electrohydraulic forming is known, which deforms a sheet against a mold by applying dynamic pressure. To this end, an electric discharge is generated between at least two electrodes in a cavity filled with liquid, for example water. An electric arc is then formed between the two electrodes causing a high temperature gradient and vaporization of the liquid. A pressure wave, also commonly called a "shock wave", travels at high speed and presses the sheet against the mold. Electrohydraulic forming is particularly advantageous in comparison with other forming processes since it allows to have a reduced springback and to obtain etching type details and / or sharp angles and / or elongations before break improved on the parts to be formed.
[0004] Dans certains cas, notamment lorsque les pièces à former sont particulièrement profondes, on réalise plusieurs décharges électriques successives. Afin de réduire le nombre de décharges électriques successives nécessaires et ainsi limiter le temps de formage d’une pièce, il a été proposé de réaliser une étape de préformage hydraulique avant le formage électrohydraulique de la pièce. Pour se faire, on remplit la cavité avec du liquide sous pression tel que décrit par exemple dans le document US7802457 B2. Lorsque la pression de liquide est suffisante, la tôle se déforme partiellement contre le moule. On génère ensuite des décharges électriques pour provoquer des ondes de choc et compléter le formage de la pièce jusqu’à atteindre la forme voulue. In certain cases, especially when the parts to be formed are particularly deep, several successive electric discharges are carried out. In order to reduce the number of successive electric discharges required and thus limit the time for forming a part, it has been proposed to carry out a hydraulic preforming step before the electrohydraulic forming of the part. To do this, the cavity is filled with pressurized liquid as described for example in document US Pat. No. 7,802,457 B2. When the liquid pressure is sufficient, the sheet partially deforms against the mold. We generate then electric discharges to cause shock waves and complete the shaping of the part until the desired shape is reached.
[0005] Le préformage de la pièce par application d’une pression quasi-statique permet de favoriser l’avalement de la tôle dans le moule, donc de réduire la déformation de la matière à réaliser par formage électrohydraulique et donc de réduire le temps de formage dans le cas où il faudrait recharger le générateur électrique impulsionnel à haute tension entre deux décharges ou de réduire la taille du générateur dans le cas où l’on souhaiterait réaliser les décharges successives sans avoir à attendre entre les décharges que le générateur se recharge. [0005] The preforming of the part by applying a quasi-static pressure makes it possible to promote the swallowing of the sheet in the mold, therefore to reduce the deformation of the material to be produced by electrohydraulic forming and therefore to reduce the processing time. forming in the case where it is necessary to recharge the high-voltage pulse electric generator between two discharges or to reduce the size of the generator in the case where it is desired to carry out successive discharges without having to wait between discharges for the generator to recharge.
[0006] Avec ces procédés, il est toutefois difficile de réaliser des pièces avec des parois verticales, c’est-à-dire des parois qui s’étendent perpendiculairement au plan de la tôle avant sa déformation. Pour pouvoir réaliser de telles parois verticales, il convient d’utiliser alors de très hautes pressions. With these methods, however, it is difficult to make parts with vertical walls, that is to say walls which extend perpendicularly to the plane of the sheet before it is deformed. In order to be able to produce such vertical walls, very high pressures should then be used.
[0007] Le document US2011/0088442 concerne un outil de formage hydromécanique qui peut comprendre des chambres de formage électrohydraulique dans lesquelles une décharge électrique peut être provoquée par des électrodes afin d’améliorer le niveau de détail qui peut être réalisé dans un moule. [0007] Document US2011 / 0088442 relates to a hydromechanical forming tool which may include electro-hydraulic forming chambers in which an electric discharge can be caused by electrodes in order to improve the level of detail that can be achieved in a mold.
[0008] Le document DE 10019594 divulgue un procédé et un dispositif pour la déformation hydromécanique de tôles déformables plastiquement, en particulier pour réaliser des pièces de carrosserie automobile, dans lesquels la tôle est placée entre un outil de formage et un coussin de liquide et dans lesquels sous l’effet d’une pression statique créée dans le coussin de liquide, la tôle est appuyée contre l’outil de formage. Simultanément à l’application de la pression statique, un générateur d’ondes de choc disposé dans le coussin de liquide est activé pour créer localement une force d’appui augmentée orientée vers des zones de la tôle. [0008] Document DE 10019594 discloses a method and a device for the hydromechanical deformation of plastically deformable sheets, in particular for producing automobile body parts, in which the sheet is placed between a forming tool and a cushion of liquid and in which under the effect of a static pressure created in the liquid cushion, the sheet is pressed against the forming tool. Simultaneously with the application of static pressure, a shock wave generator disposed in the cushion of liquid is activated to locally create an increased downforce directed towards areas of the sheet.
[0009] Le document US2012/103045 montre quant à lui un système pour le formage électrohydraulique d’une tôle dans une machine d’électrohydroformage. [0010] La présente invention vise alors à fournir un procédé et un dispositif correspondant qui permet de réaliser simplement, en mettant en œuvre de l’électro-hydro-formage, des parois verticales. [0009] Document US2012 / 103045 shows a system for the electrohydraulic forming of a sheet in an electrohydroforming machine. [0010] The present invention therefore aims to provide a method and a corresponding device which makes it possible to produce simply, by implementing electro-hydro-forming, vertical walls.
[0011] À cet effet, la présente invention propose un procédé hybride de formage d’un flan de matière dans lequel : [0011] To this end, the present invention provides a hybrid process for forming a material blank in which:
[0012] - on place le flan de matière à déformer entre une matrice et un serre-flan, [0012] - the blank of material to be deformed is placed between a die and a blank holder,
[0013] - on déforme par emboutissage à l’aide d’au moins un poinçon le flan de matière pour obtenir un flan de matière pré-embouti. [0013] The material blank is deformed by stamping using at least one punch to obtain a pre-stamped material blank.
[0014] Selon la présente invention, il est également prévu les étapes suivantes : [0014] According to the present invention, the following steps are also provided:
[0015] - on remplit de liquide une cavité dans laquelle se trouvent, d'une part, ledit au moins un poinçon et, d'autre part, au moins une paire d’électrodes, - a cavity is filled with liquid in which there are, on the one hand, said at least one punch and, on the other hand, at least one pair of electrodes,
[0016] - on met en contact le flan de matière pré-embouti avec le liquide de la cavité, et - the blank of pre-drawn material is brought into contact with the liquid of the cavity, and
[0017] - on génère au moins une décharge électrique entre au moins une paire d’électrodes de manière à déformer le flan de matière pré-embouti contre la matrice. [0017] - At least one electric discharge is generated between at least one pair of electrodes so as to deform the pre-stamped material blank against the die.
[0018] Ce procédé permet de favoriser l’avalement de la matière dans la matrice tout en offrant la possibilité de créer des parois dites verticales à l’aide du poinçon et d’avoir aussi une grande qualité de finition de la pièce grâce à l’électro hydroformage. This method makes it possible to promote the swallowing of the material in the die while offering the possibility of creating so-called vertical walls using the punch and also to have a high quality of finish of the part thanks to the electro hydroforming.
[0019] Selon une première variante de réalisation, la course relative de chaque poinçon par rapport à la matrice est limitée de telle sorte que le flan de matière lorsqu’il est poussé par le(s) poinçon(s) ne vienne pas au contact de la matrice. According to a first variant embodiment, the relative stroke of each punch relative to the die is limited so that the material blank when pushed by the punch (s) does not come into contact of the matrix.
[0020] Selon une autre variante de réalisation, la course relative d’au moins un poinçon par rapport à la matrice est telle que le flan de matière lorsqu’il est poussé par ledit au moins un poinçon vienne au contact de la matrice. [0020] According to another variant embodiment, the relative stroke of at least one punch relative to the die is such that the material blank when it is pushed by said at least one punch comes into contact with the die.
[0021] Pour améliorer encore la qualité de finition de la pièce réalisée et faciliter la mise au point des outillages en limitant la reprise manuelle du poinçon, le procédé hybride décrit ci-dessus peut comporter en outre une étape au cours de laquelle le liquide au contact du flan de matière est mis sous pression de manière à déformer le flan de matière pré-embouti. On réalise alors une étape d’hydroformage qui est réalisée de préférence après la déformation par le poinçon et avant l’électro-hydroformage. To further improve the quality of finish of the part produced and facilitate the development of the tools by limiting the manual recovery of the punch, the hybrid process described above may further include a step during which the liquid at contact of the material blank is pressurized so in deforming the pre-stamped material blank. A hydroforming step is then carried out which is preferably carried out after the deformation by the punch and before the electro-hydroforming.
[0022] Pour ne pas être gêné par de l’air qui resterait logé entre le flan de matière et la matrice, il peut être avantageusement prévu de créer une dépression entre le flan de matière et la matrice. [0022] In order not to be hampered by the air which would remain lodged between the material blank and the die, it can be advantageously provided to create a depression between the material blank and the die.
[0023] Afin de concentrer les ondes de choc créées par les décharges électriques, il a été constaté qu’il est préférable d’avoir une relativement grande proximité du poinçon avec le flan de matière lors de l’électro-hydroformage. Ainsi, on prévoit de préférence de n’éloigner le au moins un poinçon de la matrice qu’après avoir réalisé au moins une décharge électrique. [0023] In order to concentrate the shock waves created by the electric discharges, it has been found that it is preferable to have a relatively close proximity of the punch to the material blank during the electro-hydroforming. Thus, provision is preferably made to move the at least one punch away from the die only after having carried out at least one electric discharge.
[0024] La présente invention propose aussi un dispositif pour la mise en œuvre du procédé de formation hybride décrit ci-dessus. Elle propose ainsi un dispositif de formage hybride d’un flan de matière comprenant : The present invention also provides a device for implementing the hybrid training method described above. It thus offers a device for hybrid forming a material blank comprising:
[0025] - une matrice coopérant avec un serre-flan, la matrice étant mobile relativement au serre-flan entre une position dite position ouverte dans laquelle le flan de matière peut être mis en place entre la matrice et le serre-flan et en être retiré, et une autre position dite position fermée dans laquelle le serre-flan coopère avec la matrice pour maintenir de manière contrôlée tout le bord, d’un flan de matière à déformer, [0025] a die cooperating with a blank holder, the die being movable relative to the blank holder between a position called the open position in which the material blank can be placed between the die and the blank holder and be therefrom withdrawn, and another position called the closed position in which the blank holder cooperates with the die to maintain in a controlled manner the entire edge of a blank of material to be deformed,
[0026] - une cuve définissant une cavité apte à être remplie par un liquide, - a tank defining a cavity capable of being filled with a liquid,
[0027] - au moins deux électrodes placées dans la cavité, [0027] - at least two electrodes placed in the cavity,
[0028] dans lequel [0028] in which
[0029] - la cuve comporte au moins un poinçon mobile relativement à un ensemble formé par le serre-flan et la matrice en position fermée entre une position dite position éloignée dans laquelle l’extrémité libre du poinçon est à distance de la matrice et une position dite position rapprochée dans laquelle l’extrémité libre du poinçon est à une distance de la matrice inférieure à sa distance d’éloignement en position éloignée. [0030] Dans cette structure, la matrice permet de définir la forme finale de la tôle à déformer. Le poinçon est prévu pour être disposé dans la cavité et venir déformer la tôle en direction de la matrice en venant au contact de ladite tôle et en la déformant. - the tank comprises at least one movable punch relative to an assembly formed by the blank holder and the die in the closed position between a position called the remote position in which the free end of the punch is at a distance from the die and a position called the close position in which the free end of the punch is at a distance from the die less than its distance away in the remote position. In this structure, the matrix makes it possible to define the final shape of the sheet to be deformed. The punch is designed to be placed in the cavity and to deform the sheet in the direction of the die by coming into contact with said sheet and by deforming it.
[0031] Dans une variante préférée d’un tel dispositif de formage hybride, l’ensemble formé par le serre-flan et la matrice en position fermée est mobile par rapport à la cuve qui reste fixe. [0031] In a preferred variant of such a hybrid forming device, the assembly formed by the blank holder and the die in the closed position is movable relative to the tank which remains fixed.
[0032] Dans ce dispositif de formage hybride on peut également prévoir que la cuve présente un fond et une paroi périphérique, et que le bord libre de la paroi périphérique forme un poinçon. Ici la cuve et le au moins un poinçon sont de préférence une seule pièce. In this hybrid forming device it is also possible to provide that the tank has a bottom and a peripheral wall, and that the free edge of the peripheral wall forms a punch. Here, the tank and the at least one punch are preferably one piece.
[0033] Dans les cas où la cuve présente un fond et une paroi périphérique, alors on peut prévoir aussi qu’au moins un poinçon est réalisé sur un bord libre d’une paroi s’étendant à travers la cuve en divisant celle-ci en au moins deux compartiments, et qu’au moins une paire d’électrodes se situe dans chacun des deux compartiments. In cases where the tank has a bottom and a peripheral wall, then one can also provide that at least one punch is made on a free edge of a wall extending through the tank by dividing the latter into at least two compartments, and that at least one pair of electrodes is located in each of the two compartments.
[0034] Une variante préférée d’un dispositif décrit précédemment prévoit que le serre-flan est fixé sur des chandelles verticales, que la matrice est montée mobile en translation par rapport au serre-flan du côté opposé aux chandelles, que la cuve comporte un fond et une paroi périphérique, et que la cuve est montée fixe tandis que les chandelles sont coulissantes par rapport à la cuve. Les chandelles peuvent être montées par exemple sur des coussins hydrauliques. Ces chandelles peuvent être formées aussi par exemple par un ressort à gaz, un vérin hydraulique ou similaire. A preferred variant of a device described above provides that the blank holder is fixed on vertical candles, that the die is mounted mobile in translation relative to the blank holder on the side opposite the candles, that the tank has a bottom and a peripheral wall, and that the tank is mounted fixed while the candles are sliding relative to the tank. The candles can be mounted, for example, on hydraulic cushions. These candles can also be formed, for example, by a gas spring, a hydraulic cylinder or the like.
Brève description des dessins Brief description of the drawings
[0035] Des détails et avantages de la présente invention apparaîtront mieux de la description qui suit, faite en référence au dessin schématique annexé sur lequel : Details and advantages of the present invention will appear better from the following description, made with reference to the appended schematic drawing in which:
Fig. 1 Fig. 1
[0036] [Fig. 1] montre une première étape d’un procédé hybride de formage d’une tôle, le procédé étant mis en œuvre avec un dispositif de formage hybride ; Fig. 2 [0036] [Fig. 1] shows a first step of a hybrid method for forming a sheet, the method being implemented with a hybrid forming device; Fig. 2
[0037] [Fig. 2] montre une deuxième étape d’un procédé hybride de formage d’une tôle, le procédé étant mis en œuvre avec un dispositif de formage hybride ; [0037] [Fig. 2] shows a second step of a hybrid sheet metal forming process, the process being implemented with a hybrid forming device;
Fig. 3 Fig. 3
[0038] [Fig. 3] montre une troisième étape d’un procédé hybride de formage d’une tôle, le procédé étant mis en œuvre avec un dispositif de formage hybride ;[0038] [Fig. 3] shows a third step of a hybrid sheet forming process, the process being implemented with a hybrid forming device;
Fig. 4 Fig. 4
[0039] [Fig. 4] montre une quatrième étape d’un procédé hybride de formage d’une tôle, le procédé étant mis en œuvre avec un dispositif de formage hybride ; et [0039] [Fig. 4] shows a fourth step of a hybrid sheet forming process, the process being implemented with a hybrid forming device; and
Fig. 5 Fig. 5
[0040] [Fig. 5] montre une cinquième étape d’un procédé hybride de formage d’une tôle, le procédé étant mis en œuvre avec un dispositif de formage hybride ; [0040] [Fig. 5] shows a fifth step of a hybrid sheet forming process, the process being implemented with a hybrid forming device;
Description des modes de réalisation Description of embodiments
[0041] Le dessin et la description ci-après contiennent, pour l’essentiel, des éléments de caractère certain. Ils pourront donc non seulement servir à mieux faire comprendre la présente invention, mais aussi contribuer à sa définition, le cas échéant. [0041] The drawing and the description below contain, for the most part, elements of a certain nature. They can therefore not only serve to better understand the present invention, but also contribute to its definition, where appropriate.
[0042] La figure 1 représente un dispositif de formage d’un flan de matière en coupe longitudinale par un plan vertical. On supposera dans la suite de la description que le flan de matière à déformer est une tôle 2, en acier ou en alliage à base d’acier, ou bien dans un autre métal ou alliage métallique. Au départ (figure 1 ), cette tôle 2 est d’une forme donnée, par exemple plane comme illustré sur la figure 1. Une tôle en forme de calotte par exemple pourrait aussi être envisagée. [0042] Figure 1 shows a device for forming a blank of material in longitudinal section through a vertical plane. It will be assumed in the remainder of the description that the material blank to be deformed is a sheet 2, made of steel or a steel-based alloy, or else in another metal or metal alloy. Initially (Figure 1), this sheet 2 is of a given shape, for example flat as shown in Figure 1. A sheet in the shape of a cap, for example, could also be considered.
[0043] La tôle 2 à déformer est placée ici entre un serre-flan 4 et une matrice 6.The sheet 2 to be deformed is placed here between a blank holder 4 and a die 6.
Le serre-flan 4 est porté par des chandelles 8 guidées dans des logements réalisés dans un bâti inférieur posé sur le sol supposé horizontal et sur lequel une cuve 10 est solidement fixée. [0044] On suppose dans la suite de la description que les chandelles 8 s’étendent verticalement et qu’elles supportent le serre-flan 4 qui se trouve donc au-dessus des chandelles 8. De la sorte une orientation haut/bas est définie. Elle sera maintenue dans toute la suite de la présente description. The blank holder 4 is carried by candles 8 guided in housings made in a lower frame placed on the supposedly horizontal ground and on which a tank 10 is firmly fixed. It is assumed in the remainder of the description that the candles 8 extend vertically and that they support the blank holder 4 which is therefore located above the candles 8. In this way an up / down orientation is defined . It will be maintained throughout the remainder of the present description.
[0045] Le serre-flan 4 est disposé ici en dessous de la tôle 2. Il s’agit d’une pièce annulaire présentant un bord supérieur 14 adapté à la matrice 6 et à la forme que doit prendre la tôle 2 après une première déformation (opération de préformage optionnelle décrite plus bas). The blank holder 4 is arranged here below the sheet 2. It is an annular part having an upper edge 14 adapted to the die 6 and to the shape that the sheet 2 must take after a first deformation (optional preforming operation described below).
[0046] Autour du bord supérieur 14, le serre-flan 4 présente un rebord périphérique 16 servant de support pour des dispositifs compensateurs 18 destinés à coopérer avec la matrice 6 afin de maîtriser les efforts de serrage exercés par la matrice 6 et le serre-flan 4 sur la tôle 2. Around the upper edge 14, the blank holder 4 has a peripheral rim 16 serving as a support for compensating devices 18 intended to cooperate with the die 6 in order to control the clamping forces exerted by the die 6 and the clamp. blank 4 on the sheet 2.
[0047] Dans la forme de réalisation préférée illustrée au dessin, le serre-flan 4 présente une surface cylindrique 20, de section adaptée à la forme de la cuve 10, d’axe vertical. Comme expliqué plus loin, cette surface cylindrique 20 permet de réaliser une étanchéité entre le serre-flan 4 et la cuve 10. [0047] In the preferred embodiment illustrated in the drawing, the blank holder 4 has a cylindrical surface 20, of section adapted to the shape of the tank 10, of vertical axis. As explained below, this cylindrical surface 20 makes it possible to produce a seal between the blank holder 4 and the tank 10.
[0048] Le serre-flan 4 présente en outre une base inférieure 22 qui repose sur les chandelles 8. Ces dernières servent au supportage du serre-flan 4. Elles pourraient également participer au guidage du serre-flan 4 par rapport à la cuve 10. Ces chandelles peuvent être par exemple des ressorts à gaz ou bien des vérins hydrauliques. Il peut également s’agir de tiges montées sur coussins hydrauliques. Pour assurer un guidage en translation de l’ensemble formé par le serre-flan 4, la matrice 6 et la tôle 2 serrée entre ces deux éléments, par rapport à la cuve 10, des moyens de guidage extérieurs, non représentés par souci de simplification du dessin, sont préférentiellement prévus. The blank holder 4 also has a lower base 22 which rests on the candles 8. The latter serve to support the blank holder 4. They could also participate in guiding the blank holder 4 relative to the tank 10 These candles can be for example gas springs or hydraulic jacks. They can also be rods mounted on hydraulic cushions. To provide translational guidance of the assembly formed by the blank holder 4, the die 6 and the sheet 2 clamped between these two elements, relative to the tank 10, external guide means, not shown for the sake of simplicity of the drawing, are preferably provided.
[0049] La matrice 6 est la principale pièce du dispositif qui détermine la forme finale de la tôle 2 après déformation. La face inférieure de la matrice 6, c’est-à-dire celle faisant face au serre-flan 4, est destinée à donner la forme finale de la tôle 2 après déformation. Dans le procédé de formage, la tôle 2 sera poussée contre la matrice 6, plus précisément contre la face inférieure de la matrice 6, pour être déformée plastiquement et venir épouser la forme de celle-ci. [0050] La face inférieure de la matrice 6, qui correspond à la face de la matrice 6 se trouvant en vis-à-vis, d'une part, du serre-flan 4 et, d'autre part, de la cuve 10, comporte aussi une zone annulaire disposée face au bord supérieur 14 du serre- flan 4. Le bord de la tôle 2 sera maintenu durant le procédé de formage entre le bord supérieur du serre-flan 4 et la zone annulaire précitée de la face inférieure de la matrice 6. The die 6 is the main part of the device which determines the final shape of the sheet 2 after deformation. The lower face of the die 6, that is to say that facing the blank holder 4, is intended to give the final shape of the sheet 2 after deformation. In the forming process, the sheet 2 will be pushed against the die 6, more precisely against the underside of the die 6, in order to be plastically deformed and come to conform to the shape of the latter. The lower face of the die 6, which corresponds to the face of the die 6 located opposite, on the one hand, the blank holder 4 and, on the other hand, the tank 10 , also comprises an annular zone disposed facing the upper edge 14 of the hold-down 4. The edge of the sheet 2 will be maintained during the forming process between the upper edge of the hold-down 4 and the aforementioned annular zone of the lower face of matrix 6.
[0051] Dans la forme de réalisation illustrée dans laquelle il a été considéré que la cuve 10 était fixe, la matrice 6 est mobile dans un mouvement de translation verticale de manière à pouvoir se rapprocher et s’éloigner du serre-flan 4 qui dans un premier temps est destiné à rester fixe. Le serre-flan 4 restant fixe, la matrice 6 se déplace entre une première position, dite position ouverte, dans laquelle l’espace libre entre le serre-flan 4 et la matrice 6 est suffisant pour introduire une tôle 2 avant déformation et la retirer après déformation, et une seconde position dite position fermée, dans laquelle elle vient pincer le bord périphérique de la tôle 2 à déformer entre sa zone annulaire et le bord supérieur 14 du serre-flan 4. Les dispositifs compensateurs 18 assurent un jeu constant entre la matrice 6 et le serre-flan 4 correspondant à l’épaisseur de la tôle 2, plus ou moins une valeur de réglage. In the illustrated embodiment in which it was considered that the tank 10 was fixed, the die 6 is movable in a vertical translational movement so as to be able to approach and move away from the blank holder 4 which in a first step is intended to remain fixed. The blank holder 4 remaining fixed, the die 6 moves between a first position, called the open position, in which the free space between the blank holder 4 and the die 6 is sufficient to introduce a sheet 2 before deformation and to remove it. after deformation, and a second position called the closed position, in which it clamps the peripheral edge of the sheet 2 to be deformed between its annular zone and the upper edge 14 of the blank holder 4. The compensating devices 18 ensure a constant play between the die 6 and the blank holder 4 corresponding to the thickness of the sheet 2, plus or minus an adjustment value.
[0052] Dans un souci de simplification, le dessin ne montre pas les moyens mis en œuvre pour le déplacement de la matrice 6. De tels moyens sont connus de l’homme du métier du domaine technique de l’emboutissage classique par exemple. For the sake of simplicity, the drawing does not show the means implemented for moving the die 6. Such means are known to those skilled in the art of the technical field of conventional stamping, for example.
[0053] La cuve 10 remplit ici, dans cette forme de réalisation préférée, la double fonction de réceptacle pour contenir un liquide (de préférence de l’eau) et de poinçon. Elle est par la suite appelée « cuve » mais pourrait aussi être nommée « poinçon ». En variante, ces deux fonctions pourraient être dissociées, un poinçon distinct étant par exemple associé à une cuve. Cette cuve 10 présente dans la forme de réalisation illustrée une plaque de base 24 à partir de laquelle s’étend une paroi périphérique 26. La plaque de base 24 forme le fond de la cuve 10. [0053] The tank 10 fulfills here, in this preferred embodiment, the dual function of receptacle for containing a liquid (preferably water) and of punch. It is hereinafter called “tank” but could also be called “punch”. As a variant, these two functions could be dissociated, a separate punch being for example associated with a tank. This tank 10 has in the illustrated embodiment a base plate 24 from which extends a peripheral wall 26. The base plate 24 forms the bottom of the tank 10.
[0054] La paroi périphérique 26 s’étend verticalement et définit avec la plaque de base 24 (qui s’étend sensiblement à l’horizontale) une cavité pouvant être remplie avec du liquide (généralement de l’eau). La surface extérieure de la paroi périphérique 26 vient coopérer avec la surface cylindrique 20 du serre-flan pour assurer une étanchéité, par exemple à l’aide d’un joint d’étanchéité 28, lors d’un mouvement de translation verticale du serre-flan 4 autour de la paroi périphérique 26. Des moyens spécifiques, par exemple des colonnes de guidage non représentées, viennent de préférence assurer le guidage lors d’un déplacement en translation du serre-flan 4 par rapport à la cuve 10. On remarque que la surface cylindrique 20 peut venir former le bord supérieur de la cavité définie par la cuve 10 et ainsi venir prolonger cette cavité selon la position relative du serre-flan 4 par rapport à la cuve 10. The peripheral wall 26 extends vertically and defines with the base plate 24 (which extends substantially horizontally) a cavity which can be filled with liquid (generally water). The outer surface of the wall peripheral 26 cooperates with the cylindrical surface 20 of the blank holder to provide a seal, for example using a seal 28, during a vertical translational movement of the blank holder 4 around the wall peripheral 26. Specific means, for example guide columns not shown, preferably provide guidance during a translational movement of the blank holder 4 relative to the tank 10. It is noted that the cylindrical surface 20 may come form the upper edge of the cavity defined by the tank 10 and thus extend this cavity according to the relative position of the blank holder 4 with respect to the tank 10.
[0055] Dans la forme de réalisation illustrée, la partie supérieure de la cuve 10 comme mentionné plus haut constitue au moins partiellement la face supérieure du poinçon. Tout d’abord, le bord libre (opposé à la plaque de base 24) de la paroi périphérique 26 a un contour de forme adaptée à la déformation que l’on souhaite imposer à la tôle 2. Ce bord libre peut ainsi comporter des parties en saillie et/ou en creux. Ensuite, une paroi 30, sensiblement verticale, est disposée dans la cuve 10, à l’intérieur de la paroi périphérique 26. Cette paroi 30 part de la plaque de base 24 et s’étend verticalement vers la matrice 6. L’extrémité libre de la paroi 30 forme une tête 32 qui est usinée en fonction de la forme à donner à la tôle 2. In the illustrated embodiment, the upper part of the tank 10 as mentioned above at least partially constitutes the upper face of the punch. First of all, the free edge (opposite to the base plate 24) of the peripheral wall 26 has a contour of shape adapted to the deformation that one wishes to impose on the sheet 2. This free edge can thus comprise parts projecting and / or recessed. Then, a wall 30, substantially vertical, is arranged in the tank 10, inside the peripheral wall 26. This wall 30 starts from the base plate 24 and extends vertically towards the die 6. The free end of the wall 30 forms a head 32 which is machined according to the shape to be given to the sheet 2.
[0056] La paroi 30 divise de préférence la cavité intérieure de la cuve en compartiments 34. Les compartiments peuvent être étanches l’un par rapport à l’autre mais des communications (des passages) peuvent être prévus entre eux. [0056] The wall 30 preferably divides the interior cavity of the tank into compartments 34. The compartments can be sealed relative to each other but communications (passages) can be provided between them.
[0057] Bien entendu, selon la forme finale à donner à la tôle 2, plusieurs parois 30 peuvent être prévues dans la cuve. Elles peuvent être parallèles les unes par rapport aux autres, s’intersecter perpendiculairement ou selon tout angle, et plus généralement être de toute forme : droite, courbe, ondulée, ... . Of course, depending on the final shape to be given to the sheet 2, several walls 30 may be provided in the tank. They can be parallel to each other, intersect perpendicularly or at any angle, and more generally be of any shape: straight, curved, wavy, ....
[0058] Dans chaque compartiment 34, ou tout du moins dans au moins certains d’entre eux, est disposée une paire d’électrodes 36 qui sont alimentées par exemple à travers la plaque de base 24 (connections et isolants non représentés). [0058] In each compartment 34, or at least in at least some of them, is arranged a pair of electrodes 36 which are supplied for example through the base plate 24 (connections and insulators not shown).
[0059] On remarque sur le dessin la présence de butées HOF 38, c’est-à-dire des butées Hauteur Outil Fermé, qui, de manière connue de l’homme du métier, limitent précisément la fin de course de la matrice 6 (et aussi de l’ensemble formé par le serre-flan 4 et la tôle 2 entraîné par la matrice 6 lors de son déplacement). Les butées HOF sont disposées sur une surface fixe comme par exemple ici une face supérieure du bâti inférieur portant la cuve 10, autour de la paroi périphérique 26 et sont disposées entre cette plaque de base 24 et la face inférieure de la matrice 6. Elles pourraient également venir coopérer avec la base inférieure 22 du serre-flan 4. Note in the drawing the presence of HOF stops 38, that is to say, Closed Tool Height stops, which, in a manner known to those skilled in the art, precisely limit the end of travel of the die 6 (and also of the set formed by the blank holder 4 and the sheet 2 driven by the die 6 during its movement). The HOF stops are arranged on a fixed surface such as for example here an upper face of the lower frame carrying the tank 10, around the peripheral wall 26 and are arranged between this base plate 24 and the lower face of the die 6. They could also come to cooperate with the lower base 22 of the blank holder 4.
[0060] La figure 1 montre le dispositif hybride de formage dans une position correspondant à une première étape d’un procédé de formage. Dans cette position, la matrice 6 est en position ouverte, c’est-à-dire dans sa position la plus éloignée du serre-flan 4 (et de la cuve 10 incluant le poinçon 26, 32). Comme mentionné plus haut, le serre-flan 4 et la matrice 6 sont alors assez espacés l’un de l’autre pour permettre notamment l’introduction d’une tôle 2 entre eux. La figure 1 illustre la mise en place de cette tôle 2, cette mise en place étant suggérée par la flèche 40 sur la gauche de cette figure 1. [0060] Figure 1 shows the hybrid forming device in a position corresponding to a first step of a forming process. In this position, the die 6 is in the open position, that is to say in its position furthest from the blank holder 4 (and from the vessel 10 including the punch 26, 32). As mentioned above, the blank holder 4 and the die 6 are then sufficiently spaced from one another to allow in particular the introduction of a sheet 2 between them. Figure 1 illustrates the placement of this sheet 2, this placement being suggested by the arrow 40 on the left of this figure 1.
[0061] Dans la position de la figure 1 , le serre-flan 4 est dans une position haute, c’est-à-dire une position dans laquelle le serre-flan 4 qui porte la tôle 2 est positionné de telle sorte que la partie supérieure de la cuve 10 formant le poinçon ne peut pas venir au contact de la tôle 2. De l’eau peut être déjà présente dans les compartiments 34 de la cuve 10. La matrice 6 est disposée au-dessus de la tôle 2. In the position of Figure 1, the blank holder 4 is in a high position, that is to say a position in which the blank holder 4 which carries the sheet 2 is positioned such that the upper part of the tank 10 forming the punch cannot come into contact with the sheet 2. Water may already be present in the compartments 34 of the tank 10. The die 6 is arranged above the sheet 2.
[0062] La figure 2 illustre une étape ultérieure. Par rapport à la figure 1 , la matrice 6 est descendue comme suggéré par une flèche 42. Le bord périphérique de la tôle 2 est pincé entre la zone annulaire de la matrice 6 et le bord supérieur du serre-flan 4. La force de serrage entre la matrice 6 et le serre-flan 4 est réglée par les dispositifs compensateurs 18 qui sont disposés entre le rebord périphérique 16 du serre-flan 4 et un bord de la matrice 6 (en tenant compte aussi d’une compensation de forces qui peut être réalisée au niveau de chacune des chandelles 8). Dans le procédé illustré au dessin, il n’est pas prévu de déformation de la tôle 2 lors de cette étape. Les zones de contact, d'une part, entre la tôle 2 et la matrice 6 et, d'autre part, entre la tôle 2 et le serre-flan 4 sont de préférence parallèles. Figure 2 illustrates a subsequent step. Compared to Figure 1, the die 6 is lowered as suggested by an arrow 42. The peripheral edge of the sheet 2 is clamped between the annular zone of the die 6 and the upper edge of the blank holder 4. The clamping force between the die 6 and the blank holder 4 is regulated by the compensating devices 18 which are arranged between the peripheral edge 16 of the blank holder 4 and an edge of the die 6 (also taking into account a compensation of forces which can be carried out at each of the candles 8). In the process illustrated in the drawing, there is no provision for deformation of the sheet 2 during this step. The contact zones, on the one hand, between the sheet 2 and the die 6 and, on the other hand, between the sheet 2 and the blank holder 4 are preferably parallel.
[0063] En variante, le serrage de la matrice 6 sur la tôle 2 pourrait être utilisé afin de réaliser un premier préformage de la tôle 2, par exemple pour incurver cette dernière et/ou pour conformer son bord. On peut provoquer ainsi (optionnellement) une première déformation à la tôle 2. Le serrage de la matrice 6 sur le serre-flan 4 permet en outre de garantir une étanchéité à l’eau entre la tôle 2 et le serre-flan 4. Un jonc périphérique peut être aussi éventuellement formé sur la tôle 2 entre la matrice 6 et le serre-flan 4 pour garantir une bonne étanchéité entre la tôle 2 et le serre-flan 4. Un joint d’étanchéité élastomère peut également remplir cette fonction d’étanchéité. Alternatively, the clamping of the die 6 on the sheet 2 could be used in order to perform a first preforming of the sheet 2, for example to bend this last and / or to conform its edge. It is thus possible (optionally) to cause a first deformation of the sheet 2. The clamping of the die 6 on the blank holder 4 also makes it possible to guarantee a watertight seal between the sheet 2 and the blank holder 4. A Peripheral ring can also optionally be formed on the sheet 2 between the die 6 and the blank holder 4 to guarantee a good seal between the sheet 2 and the blank holder 4. An elastomeric seal can also fulfill this function of sealing.
[0064] De l’eau vient alors remplir tout l’espace délimité par l’intérieur de la cuve 10, la tôle 2, la surface cylindrique 20 du serre-flan 4 et le(s) joint(s) d’étanchéité 28. Le remplissage d’eau a pour but de venir remplir la cavité de telle sorte que le liquide vienne au contact de la tôle 2 éventuellement préformée. Il peut être réalisé par exemple en aspirant l’air se trouvant en-dessous de la tôle 2. Une aspiration simultanée de l’air au-dessus de la tôle 2 est également réalisée pour maintenir sensiblement une même pression des deux côtés de la tôle 2. L’aspiration d’air entre la tôle 2 et la matrice 6 est de préférence maintenue durant tout le procédé de déformation pour éviter que l’air se trouvant dans cet espace ne gêne la déformation de la tôle 2. En variante, on peut prévoir d’évacuer l’air par des trous d’évacuation situés à un point haut du serre-flan 4 lors de la montée de l’eau dans la cavité. Pendant cette phase, si la tôle présente une forme concave, de l’air pressurisé peut être utilisé pour maintenir une concavité à la tôle, limitant ainsi les bulles d’air sous celle-ci. Le serre-flan 4 reste lors de ce remplissage dans la même position que sur la figure 1. Water then fills the entire space delimited by the interior of the tank 10, the sheet 2, the cylindrical surface 20 of the blank holder 4 and the seal (s) 28 The purpose of filling with water is to come and fill the cavity so that the liquid comes into contact with the possibly preformed sheet 2. It can be carried out for example by sucking in the air located below the sheet 2. A simultaneous suction of the air above the sheet 2 is also carried out to maintain substantially the same pressure on both sides of the sheet. 2. The air suction between the sheet 2 and the die 6 is preferably maintained throughout the deformation process to prevent the air in this space interfering with the deformation of the sheet 2. As a variant, it is may provide for evacuating the air through evacuation holes located at a high point of the blank holder 4 when the water rises in the cavity. During this phase, if the sheet has a concave shape, pressurized air can be used to maintain a concavity in the sheet, thus limiting air bubbles beneath it. The blank holder 4 remains during this filling in the same position as in Figure 1.
[0065] Par la suite (figure 3), la matrice 6 continue de descendre vers la cuve 10, et entraîne la descente du serre-flan 4 par rapport à la cuve 10-flèche 44. Le poinçon formé par la cuve 10, plus particulièrement le bord périphérique supérieur de la paroi périphérique 26 et la (les) tête(s) 32 viennent alors au contact de la tôle 2 et déforment celle-ci plastiquement par étirage. Lors de ce mouvement, le poinçon vient exercer une force venant pousser la tôle 2 vers la matrice 6. La tôle 2 maintenue entre le serre-flan 4 et la matrice 6 est disposée entre le poinçon et la matrice 6. Le poinçon et/ou la cuve 10 agissent comme une pièce mâle venant coopérer avec la matrice 6, pièce femelle qui présente ici un logement pour recevoir le poinçon formé par la partie supérieure de la cuve 10. Les dispositifs compensateurs 18 agissent ici pour réguler la tension au bord de la tôle 2 et autoriser si nécessaire un déplacement de matière de la tôle 2 vers l’intérieur du système. Subsequently (Figure 3), the die 6 continues to descend towards the tank 10, and causes the descent of the blank holder 4 relative to the tank 10-arrow 44. The punch formed by the tank 10, more particularly the upper peripheral edge of the peripheral wall 26 and the head (s) 32 then come into contact with the sheet 2 and deform the latter plastically by stretching. During this movement, the punch exerts a force that pushes the sheet 2 towards the die 6. The sheet 2 held between the blank holder 4 and the die 6 is placed between the punch and the die 6. The punch and / or the tank 10 act as a male part which cooperates with the die 6, a female part which here has a housing for receiving the punch formed by the upper part of the tank 10. The devices compensators 18 act here to regulate the tension at the edge of the sheet 2 and allow, if necessary, a displacement of material from the sheet 2 towards the interior of the system.
[0066] Une deuxième étape de déformation (le préformage éventuel évoqué plus haut étant la première étape de déformation) de la tôle 2 est réalisée ici. Il s’agit ici d’une étape d’emboutissage. Au cours de cette étape de déformation, on veille de préférence, mais pas obligatoirement, à ce que la tôle 2 ne vienne pas toucher la matrice 6 dans sa zone centrale, c’est-à-dire dans la zone se trouvant en vis-à-vis de l’intérieur de la paroi périphérique 26. Toutefois, dans certains cas, on peut par exemple prévoir à certains endroits une déformation « complète » de la tôle 2 lors de cette opération d’emboutissage. Ceci permet d’éviter d’avoir à prévoir des électrodes pour « couvrir » toute la surface de la tôle 2. A second deformation step (the possible preforming mentioned above being the first deformation step) of the sheet 2 is carried out here. This is a stamping step. During this deformation step, care is preferably taken, but not necessarily, that the sheet 2 does not come into contact with the die 6 in its central zone, that is to say in the zone located opposite. vis-à-vis the inside of the peripheral wall 26. However, in certain cases, it is for example possible to provide in certain places a “complete” deformation of the sheet 2 during this stamping operation. This avoids having to provide electrodes to "cover" the entire surface of the sheet 2.
[0067] La figure 4 illustre une étape avantageuse mais optionnelle du procédé de formage hybride. Il est proposé ici d’avoir une étape d’hydroformage quasi- statique de la tôle 2 au cours de laquelle cette tôle 2 vient encore s’approcher de la matrice 6 et peut localement entrer en contact avec elle. Cette déformation de la tôle 2 est alors obtenue en mettant sous pression l’eau se trouvant dans la cuve 10, par exemple en agissant sur la matrice 6 (flèche 42). La tôle 2 se sépare donc au moins localement du poinçon formé par la partie supérieure de la cuve 10 et vient prendre une position intermédiaire entre la matrice 6 et la (les) tête(s) 32 et le bord supérieur de la paroi périphérique 26 formant le poinçon. FIG. 4 illustrates an advantageous but optional step of the hybrid forming process. It is proposed here to have a virtually static hydroforming step of the sheet 2 during which this sheet 2 still comes close to the die 6 and can locally come into contact with it. This deformation of the sheet 2 is then obtained by putting the water in the tank 10 under pressure, for example by acting on the die 6 (arrow 42). The sheet 2 therefore separates at least locally from the punch formed by the upper part of the tank 10 and takes an intermediate position between the die 6 and the head (s) 32 and the upper edge of the peripheral wall 26 forming the punch.
[0068] L’homme du métier aura déjà remarqué que les figures annexées sont schématiques et simplement illustratives. Les déformations et les détails ne sont pas à l’échelle. [0068] Those skilled in the art will have already noticed that the appended figures are schematic and merely illustrative. Distortions and details are not to scale.
[0069] La figure 5 illustre une étape ultérieure du procédé de formage de la tôle 2. Un électro-hydroformage est montré schématiquement ici. Une chambre de décharge est formée ici et entièrement remplie d’eau. Elle comprend la cavité à l’intérieur de la cuve et s’étend au-delà jusqu’à la tôle 2 déformée et jusqu’à l’étanchéité réalisée entre la cuve et le serre-flan 4. Les paires d’électrodes 36, disposées dans ladite chambre de décharge, sont alors alimentées par un fort courant issu d’une décharge de condensateurs. De manière connue, cette décharge électrique crée dans le liquide (eau) contenu dans la cuve 10 et au contact de la tôle 2 (il est important d’avoir un bon remplissage d’eau dans la cuve 10 de manière à ce que l’eau soit bien au contact de la tôle 2 pour cette étape d’électro-hydroformage) une explosion créant une onde de choc qui se propage vers la tôle 2. La (les) paroi(s) 30 et la paroi périphérique 26 viennent guider les ondes de choc et agissent ainsi pour permettre une bonne déformation de la tôle 2 contre la matrice 6. FIG. 5 illustrates a subsequent step in the process for forming the sheet 2. An electro-hydroforming is shown schematically here. A discharge chamber is formed here and completely filled with water. It includes the cavity inside the tank and extends beyond to the deformed sheet 2 and to the seal produced between the tank and the blank holder 4. The pairs of electrodes 36, arranged in said discharge chamber, are then supplied by a strong current from a discharge of capacitors. In a known manner, this electric discharge creates in the liquid (water) contained in the tank 10 and in the contact with sheet 2 (it is important to have a good filling of water in tank 10 so that the water is in contact with sheet 2 for this electro-hydroforming step) an explosion creating a shock wave which propagates towards the sheet 2. The wall (s) 30 and the peripheral wall 26 guide the shock waves and thus act to allow good deformation of the sheet 2 against the die 6.
[0070] Dans ce procédé, une seule décharge électrique dans les paires d’électrodes 36 est normalement suffisante pour obtenir la déformation souhaitée grâce aux déformations préalables de la tôle 2, avant l’étape d’électro hydroformage. In this process, a single electric discharge in the pairs of electrodes 36 is normally sufficient to obtain the desired deformation thanks to the prior deformations of the sheet 2, before the electro-hydroforming step.
[0071] Le dessin ne représente pas les dernières étapes qui concernent le retrait de la pièce qui a été formée à partir de la tôle 2, avec ouverture du moule et redescente de la cuve vers sa position illustrée sur la figure 1. The drawing does not represent the last steps which relate to the withdrawal of the part which was formed from the sheet 2, with the mold opening and the tank lowering to its position illustrated in FIG. 1.
[0072] Le procédé présenté ici permet donc de réaliser des pièces avec un temps de cycle réduit car une seule passe d’électro-hydroformage est nécessaire. Les opérations d’étirage sur poinçon (appelé aussi en anglais « stretch draw ») et éventuellement d’hydroformage sont réalisées quasiment en temps masqué. The process presented here therefore makes it possible to produce parts with a reduced cycle time because only one electro-hydroforming pass is necessary. The stretching operations on a punch (also called "stretch draw") and possibly hydroforming are carried out almost in masked time.
[0073] Un grand avantage du procédé présenté ici est que la tôle après déformation peut présenter des parois verticales (à l’angle de dépouille près pour pouvoir séparer en fin de processus la tôle formée de la matrice 6), autrement dit, la pièce obtenue par déformation de la tôle peut présenter des faces qui s’étendent sensiblement perpendiculairement à l’orientation de la tôle avant déformation. Dans l’exemple illustré sur le dessin, la tôle est initialement dans un plan horizontal. Après déformation, elle peut alors présenter des faces quasiment verticales (avant retrait de la pièce hors du système). A great advantage of the process presented here is that the sheet after deformation can have vertical walls (up to the draft angle to be able to separate at the end of the process the sheet formed from the die 6), in other words, the part obtained by deformation of the sheet may have faces which extend substantially perpendicular to the orientation of the sheet before deformation. In the example shown in the drawing, the sheet is initially in a horizontal plane. After deformation, it can then have almost vertical faces (before the part is withdrawn from the system).
[0074] Le procédé de formage et le dispositif de formage hybrides proposés ici permettent d’obtenir par électro-hydroformage des pièces avec des parois quasi- verticales avec un temps de cycle réduit. Le prix de revient de telles pièces peut ainsi être limité. The forming process and the hybrid forming device proposed here make it possible to obtain by electro-hydroforming parts with almost vertical walls with a reduced cycle time. The cost price of such parts can thus be limited.
[0075] Selon une variante de réalisation, les parois dans la cuve (le poinçon) pourraient par exemple former une structure alvéolaire de type nid d’abeille. [0076] Il est prévu dans la forme de réalisation illustrée que la paroi périphérique de la cuve soit une partie du poinçon destiné à déformer la tôle par emboutissage. Cela dépend bien entendu de la forme que l’on souhaite donner à la tôle. La paroi périphérique de la cuve ne fait pas forcément partie du poinçon. On pourrait par exemple prévoir sur la figure 3 que le serre-flan affleure avec le bord supérieur de la paroi périphérique de la cuve. According to an alternative embodiment, the walls in the tank (the punch) could for example form a honeycomb-type alveolar structure. It is provided in the illustrated embodiment that the peripheral wall of the tank is part of the punch intended to deform the sheet by stamping. This of course depends on the shape that one wishes to give to the sheet. The peripheral wall of the tank is not necessarily part of the punch. Provision could for example be made in FIG. 3 for the blank holder to be flush with the upper edge of the peripheral wall of the tank.
[0077] Dans le dispositif présenté, il a été supposé que la cuve était fixe. Il s’agit d’une forme de réalisation préférée mais on pourrait avoir une matrice fixe. L’homme du métier comprend bien que c’est le mouvement relatif entre les divers éléments constituant le système qui est important. In the device presented, it was assumed that the tank was fixed. This is a preferred embodiment but one could have a fixed die. Those skilled in the art understand that it is the relative movement between the various elements constituting the system that is important.
[0078] La présente invention ne se limite pas aux différentes formes de réalisation décrites et illustrées et aux variantes évoquées mais elle concerne également les formes de réalisation à la portée de l’homme du métier dans le cadre des revendications ci-après. [0078] The present invention is not limited to the various embodiments described and illustrated and to the variants mentioned, but it also relates to the embodiments within the reach of those skilled in the art within the framework of the claims below.

Claims

Revendications Claims
[Revendication 1] Procédé hybride de formage d’un flan de matière dans lequel : [Claim 1] Hybrid method of forming a material blank in which:
- on place un flan de matière (2) à déformer entre une matrice (6) et un serre-flan- a blank of material (2) to be deformed is placed between a die (6) and a blank holder
(4), (4),
- on déforme par emboutissage à l’aide d’au moins un poinçon (26, 32) le flan de matière (2) pour obtenir un flan de matière (2) pré-embouti, - the material blank (2) is deformed by stamping using at least one punch (26, 32) to obtain a pre-stamped material blank (2),
caractérisé en ce que characterized in that
- on remplit de liquide une cavité dans laquelle se trouvent, d'une part, le au moins un poinçon (26, 32) ayant pré-embouti le flan de matière (2) et, d'autre part, au moins une paire d’électrodes (36), - A cavity is filled with liquid in which there are, on the one hand, the at least one punch (26, 32) having pre-stamped the material blank (2) and, on the other hand, at least one pair of 'electrodes (36),
- on met en contact le flan de matière (2) pré-embouti avec le liquide de la cavité, et - the pre-stamped material blank (2) is brought into contact with the liquid in the cavity, and
- on génère au moins une décharge électrique entre au moins une paire d’électrodes (36) de manière à déformer le flan de matière (2) pré-embouti contre la matrice (6). - At least one electric discharge is generated between at least one pair of electrodes (36) so as to deform the material blank (2) pre-stamped against the die (6).
[Revendication 2] Procédé hybride selon la revendication 1 , caractérisé en ce que la course relative de chaque poinçon (26, 32) par rapport à la matrice (6) est limitée de telle sorte que le flan de matière (2) lorsqu’il est poussé par le(s) poinçon(s) ne vienne pas au contact de la matrice (6). [Claim 2] A hybrid method according to claim 1, characterized in that the relative stroke of each punch (26, 32) with respect to the die (6) is limited such that the material blank (2) when is pushed by the punch (s) does not come into contact with the die (6).
[Revendication 3] Procédé hybride selon la revendication 1 , caractérisé en ce que la course relative d’au moins un poinçon (26, 32) par rapport à la matrice (6) est telle que le flan de matière (2) lorsqu’il est poussé par ledit au moins un poinçon vienne au contact de la matrice (6). [Claim 3] A hybrid method according to claim 1, characterized in that the relative stroke of at least one punch (26, 32) with respect to the die (6) is such that the material blank (2) when is pushed by said at least one punch comes into contact with the die (6).
[Revendication 4] Procédé hybride selon l'une des revendications 1 à 3, caractérisé en ce qu’il comporte en outre une étape au cours de laquelle le liquide au contact du flan de matière (2) est mis sous pression de manière à déformer le flan de matière (2) pré-embouti. [Claim 4] Hybrid method according to one of claims 1 to 3, characterized in that it further comprises a step during which the liquid in contact with the blank of material (2) is pressurized so as to deform the pre-stamped material blank (2).
[Revendication 5] Procédé hybride selon l’une des revendications 1 à 4, caractérisé en ce qu’on crée un vide entre le flan de matière (2) et la matrice (6). [Revendication 6] Procédé hybride selon l'une des revendications 1 à 5, caractérisé en ce qu’on n’éloigne le au moins un poinçon (26, 32) de la matrice [Claim 5] Hybrid method according to one of claims 1 to 4, characterized in that a vacuum is created between the material blank (2) and the die (6). [Claim 6] Hybrid method according to one of claims 1 to 5, characterized in that the at least one punch (26, 32) is not moved away from the die
(6) qu’après avoir réalisé au moins une décharge électrique. (6) only after performing at least one electric shock.
[Revendication 7] Dispositif de formage hybride d’un flan de matière comprenant : [Claim 7] Device for hybrid forming a material blank comprising:
- une matrice (6) coopérant avec un serre-flan (4), la matrice (6) étant mobile relativement au serre-flan (4) entre une position dite position ouverte dans laquelle un flan de matière (2) peut être mis en place entre la matrice (6) et le serre-flan (4) et en être retiré et une autre position dite position fermée dans laquelle le serre- flan (4) coopère avec la matrice (6) pour maintenir de manière contrôlée un bord, de préférence tout le bord, d’un flan de matière (2) à déformer, - a die (6) cooperating with a blank holder (4), the die (6) being movable relative to the blank holder (4) between a position called the open position in which a material blank (2) can be placed place between the die (6) and the blank holder (4) and be withdrawn therefrom and another position called the closed position in which the blank holder (4) cooperates with the die (6) to maintain an edge in a controlled manner, preferably the entire edge of a blank of material (2) to be deformed,
- une cuve (10) définissant une cavité apte à être remplie par un liquide, - a tank (10) defining a cavity capable of being filled with a liquid,
- au moins deux électrodes (36) placées dans la cavité, - at least two electrodes (36) placed in the cavity,
caractérisé en ce que characterized in that
- la cuve (10) comporte au moins un poinçon (26, 32) mobile relativement à un ensemble formé par le serre-flan (4) et la matrice (6) en position fermée entre une position dite position éloignée dans laquelle l’extrémité libre du poinçon est à distance de la matrice (6) et une position dite position rapprochée dans laquelle l’extrémité libre du poinçon est à une distance de la matrice (6) inférieure à sa distance d’éloignement en position éloignée. - the tank (10) comprises at least one punch (26, 32) movable relative to an assembly formed by the blank holder (4) and the die (6) in the closed position between a position called the remote position in which the end free of the punch is at a distance from the die (6) and a position called the close position in which the free end of the punch is at a distance from the die (6) less than its distance away in the remote position.
[Revendication 8] Dispositif de formage hybride selon la revendication 7, caractérisé en ce que l’ensemble formé par le serre-flan (4) et la matrice (6) en position fermée est mobile par rapport à la cuve (10) qui reste fixe. [Claim 8] A hybrid forming device according to claim 7, characterized in that the assembly formed by the blank holder (4) and the die (6) in the closed position is movable relative to the tank (10) which remains fixed.
[Revendication 9] Dispositif de formage hybride selon l'une des revendications 7 ou 8, caractérisée en ce que la cuve (10) présente un fond (24) et une paroi périphérique (26), et en ce que le bord libre de la paroi périphérique (26) forme un poinçon. [Claim 9] A hybrid forming device according to one of claims 7 or 8, characterized in that the vessel (10) has a bottom (24) and a peripheral wall (26), and in that the free edge of the peripheral wall (26) forms a punch.
[Revendication 10] Dispositif de formage hybride selon l'une des revendications 7 à 9, caractérisé en ce que la cuve (10) présente un fond (24) et une paroi périphérique (26), [Claim 10] A hybrid forming device according to one of claims 7 to 9, characterized in that the vessel (10) has a bottom (24) and a peripheral wall (26),
en ce qu’au moins un poinçon est réalisé sur un bord libre d’une paroi (30) s’étendant à travers la cuve (10) en divisant celle-ci en au moins deux compartiments (34), et en ce qu’au moins une paire d’électrodes (36) se situe dans chacun des deux compartiments (34). in that at least one punch is made on a free edge of a wall (30) extending through the tank (10) dividing the latter into at least two compartments (34), and in that at least one pair of electrodes (36) is located in each of the two compartments (34).
[Revendication 11] Dispositif de formage hybride selon l'une des revendications 7 à 10, caractérisé en ce que le serre-flan (4) est fixé sur des chandelles (8) verticales, en ce que la matrice (6) est montée mobile en translation par rapport au serre-flan (4) du côté opposé aux chandelles (8), en ce que la cuve (10) comporte un fond et une paroi périphérique (26), et en ce que la cuve (10) est montée fixe tandis que les chandelles (8) sont coulissantes par rapport à la cuve (10). [Claim 11] Hybrid forming device according to one of claims 7 to 10, characterized in that the blank holder (4) is fixed on vertical candles (8), in that the die (6) is mounted mobile in translation with respect to the blank holder (4) on the side opposite to the candles (8), in that the tank (10) comprises a bottom and a peripheral wall (26), and in that the tank (10) is mounted fixed while the candles (8) are sliding relative to the tank (10).
EP20709285.9A 2019-02-13 2020-02-11 Hybrid forming method and corresponding forming device Pending EP3924117A1 (en)

Applications Claiming Priority (2)

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FR1901446A FR3092504B1 (en) 2019-02-13 2019-02-13 Hybrid forming process and corresponding forming device
PCT/FR2020/050247 WO2020165538A1 (en) 2019-02-13 2020-02-11 Hybrid forming method and corresponding forming device

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EP (1) EP3924117A1 (en)
JP (1) JP7418456B2 (en)
CN (1) CN113412169B (en)
FR (1) FR3092504B1 (en)
WO (1) WO2020165538A1 (en)

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FR3092504B1 (en) 2021-01-22
JP7418456B2 (en) 2024-01-19
US20220126350A1 (en) 2022-04-28
US11897017B2 (en) 2024-02-13
FR3092504A1 (en) 2020-08-14
JP2022523181A (en) 2022-04-21
CN113412169A (en) 2021-09-17
CN113412169B (en) 2023-11-03

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