EP1525062A1

EP1525062A1 - Method for making a tool for forming a material and tool obtainable by said method

Info

Publication number: EP1525062A1
Application number: EP03755631A
Authority: EP
Inventors: Philippe Chapuis
Original assignee: FINANC D ETUDES ET DE DEV IND; FINANCIERE D'ETUDES ET DE DEVELOPPEMENTS INDUSTRIELS ET TECHNOLOGIQUES Ste
Current assignee: ThyssenKrupp Sofedit SAS
Priority date: 2002-07-26
Filing date: 2003-07-25
Publication date: 2005-04-27
Also published as: FR2842753A1; CN1318158C; FR2842753B1; WO2004011171A1; US20060138698A1; CA2493801A1; CN1700960A; AU2003273471A1

Abstract

The invention concerns a method for making a material-shaping tool, in particular by hot pressing or injection moulding. The tool (2) consists of an integral assembly of sections (35, 36, 37, 38, 39, 40) mutually adjacent along junction surfaces (41, 42, 43, 44, 45, 46, 47, 48, 49, 50). Grooves (51, 52, 55, 56, 58, 59) provided in said junction surfaces (41, 42, 43, 44, 45, 46, 47, 48, 49, 50) and passages (53, 54, 57, 30, 62, 63, 64, 65, 66, 67) provided through said sections (36, 37, 38, 39) define a circuit (13) for circulating a heating medium. Each section (36, 37, 38, 39, 40) can be designed and produced, for example by moulding or machining in a bloc of heat-conducting material, so as to ensure an optimal configuration of the heating medium circuit (13) in the tool (2).

Description

METHOD FOR PRODUCING A TOOL FOR

FORMING A SUSCEPTIBLE MATERIAL AND TOOL

TO BE CARRIED OUT BY THIS PROCESS

The present invention relates to a method for producing a tool intended for forming a material, in particular by hot stamping or injection-molding, for the purpose of making it an object of determined shape, said tool having to present for this purpose a forming face of complementary shape of at least part of said determined shape, said method comprising an initial step a consisting in projecting an outline of the tool to be produced, comprising a projected forming face having said complementary shape, and in design inside said projected contour, as a function of said complementary shape, a projected circuit for circulation of a heat transfer fluid inside the tool to be produced, said projected circuit comprising a plurality of projected conduits, at least one of which '' constitutes a projected collector and of which at least another constitutes a projected derivation of the projected collector and runs along the project forming face e.

By way of nonlimiting examples of tool likely to be concerned by this process, mention may be made of the punches and dies used for the stamping of hot sheets and the parts which, in an injection-molding mold d '' a thermoplastic material, define a molding imprint. In these two examples, the heat transfer fluid which is circulated inside the tool is intended to cool the latter and, by thermal conduction through the latter, the object being produced, in order to cause it to soak in the case of hot stamping and to accelerate its solidification in the case of injection-molding. In other applications, such as thermoforming of thermoplastic materials, it is also possible to give the heat-transfer fluid a function of heating the object in progress by thermal conduction through the tool, or even to alternate circulation of heating fluid. and coolant.

In the current state of the art, after the abovementioned initial step, the tool is produced by traditional foundry techniques, which have certain drawbacks. One of these drawbacks lies in the high overall cost of producing a forming tool using these foundry techniques. Admittedly, these techniques are generally inexpensive in themselves, but their application to the production of a forming tool requires reworking of precision machining as for them delicate and expensive. In fact, the tool is generally produced in this case in the form of two mutually interlocking foundry pieces, on the basis of a comparatively fine piece, defining the forming face in its entirety and having, on the opposite side, a network of open channels. corresponding to the branches of the heat transfer fluid circuit, and of a comparatively massive part, serving as a support connection of the comparatively fine part on a sole or a bed base of a machine, for example hot stamping or injection -molding, on the one hand, closing the channels of the comparatively fine part and containing the rest of the conduits of the heat transfer fluid circuit, on the other hand. So, the need for as good a quality as possible of the mechanical support of the comparatively fine part on the comparatively massive part, by mutual interlocking faces of generally complex shape, and of the comparatively massive part on the sole or the box spring, certainly by mutual support faces of generally simpler shape, as well as the concern of mutually isolating the channels against leaks of heat transfer fluid from one to the other oblige to machine the faces d 'mutual interlocking and mutual support faces with great precision, particularly difficult with regard to at least the mutual interlocking faces due to their generally complex shape. In practice, experience shows that even with particularly careful machining, it is difficult to avoid leakage of heat transfer fluid between the channels, if only because of expansion phenomena can cause a certain play between the faces d 'mutual interlocking, so that it is difficult to control the circulation of heat transfer fluid and the action thereof on the workpiece when using the tools of the prior art. Another drawback lies in the fact that the foundry techniques and the raw materials capable of being treated by these techniques to produce the tools do not make it possible to give these tools mechanical resistance characteristics, in particular to abrasion, and heat conduction as good as would be desirable, especially in the case of hot stamping tools.

Yet another drawback lies in the fact that technical imperatives, in particular as regards the coring of foundry molds, impose limitations on the practical implementation of the circulation circuit of the heat-transfer fluid, that is to say do not allow '' optimizing the layout of this circuit as a function of the shape of the forming face and of the specific needs in circulation of heat transfer fluid, that is to say generally in cooling, of different zones of the forming face and of the object in progress, for example as a function of the thickness that the object may have with regard to these different zones, both in the case of hot stamping and in the case of injection molding, or as a function of friction forces undergone by these different zones, in the case of hot stamping.

The object of the present invention is to remedy these drawbacks, that is to say to allow the production of tools which, at the same time, have optimized mechanical characteristics depending on the process for forming a material to which they are intended, that is to say in particular in terms of resistance to abrasion by the material being formed, comprise a circuit for circulation of heat-transfer fluid which best respects an optimal configuration in terms of circulation needs of the heat-transfer fluid in particular according to the areas of the forming face, and have thermal conductivity characteristics as good as possible, in particular between this heat transfer fluid circuit and the forming face.

To this end, the present invention provides a method of the type indicated in the preamble, characterized: - in that the initial step a is implemented by placing at least one first conduit projected along an average surface as simple as possible, the mean surface of the or each first projected conduit being secant from the projected forming surface, by defining sections of the projected forming face therein, and of at least one second projected duct, by defining therein sections of the or each second projected duct, and

- in that the method then comprises the succession of steps consisting in: "b: producing tool slices, each of which is delimited in particular by at least one junction face, at least some junction faces reproducing at least approximately a surface respective mean, namely commonly by two junction faces reproducing at least approximately respectively one and the other of two respective mean surfaces, and by at least the outline of a useful face reproducing a respective section of face of projected forming, adjacent to said respective average surface, namely commonly a section of projected forming face delimited by said two respective medium surfaces, and comprises on the one hand, in its mass, a passage reproducing the respective section of or each second conduit projected and opening into the or each junction face and on the other hand, in the or each junction face, a groove connected as a branch on said passage and reproducing at least approximately one half of the first respective projected conduit, "c: juxtapose the tool edges by their junction faces and secure them mutually in a position relative in which the useful faces or said blanks, passages and grooves complement each other from one edge to the other to respectively constitute the forming face or a blank of forming face, the or each second conduit and the or each first conduit, and if necessary machine the forming face blank to produce the forming face. Insofar as the tool thus obtained has a structure in itself characteristic, the present invention extends to a tool capable of '' be produced by the method according to the invention and intended for the forming of a material, in particular by hot stamping or injection-molding, in order to make it a object of determined shape, said tool having for this purpose a forming face of complementary shape of at least part of said determined shape and an internal circuit for circulation of a heat-transfer fluid, said circuit comprising a plurality of conduits of which at least one constitutes a collector and of which at least another constitutes a derivation of the collector and runs along the forming face, characterized in that it consists of an integral assembly of tool edges mutually juxtaposed by junction faces of which at least some coincide at least approximately with a medium surface, as simple as possible, of a first conduit and which intersect the forming face, by defining sections of the forming face therein, and of at least one second conduit, by defining therein sections of second conduit .

A person skilled in the art will readily understand that it is certainly possible to produce at least one, or even each of the tool slices in foundry, during step b, from raw materials suitable for them if these allow to obtain in particular the mechanical and thermal characteristics desired for this or these tool wafers, but that it is also possible to produce the tool wafers, during step b, by machining in a preexisting block of a thermally conductive raw material, and in particular in such a raw material not suitable for the production of foundry parts, so that the method according to the invention considerably extends the choice of raw materials which can be used for the production of a tool for forming, for example by hot stamping or injection molding.

In particular, the raw material of the tool can thus be chosen from a group comprising cupro- Al ₂ 0 ₃ , cupro-cadmium, cupro-beryllium and stainless steels, which, in the current state of the art , do not lend themselves or lend themselves poorly to the production of tools in foundry work and are of much greater interest than that of materials suitable for foundry work, both in terms of thermal conductivity and in terms of mechanical strength, in particular abrasion. In addition, whether a tool section is made in a foundry or by machining in a preexisting block of thermally conductive raw material, the arrangement of a section of second pipe in each of the sections and of a first pipe at least approximately by half in each junction face between sections and the possibility of conforming at will each of the sections, in particular with regard to their junction faces, allow the positions of the average surfaces of the first conduits to be freely chosen one relative to the other as well as with respect to the forming face, and consequently to optimize the layout of the circulation circuit of the heat transfer fluid as a function of imperatives linked to the shape of the forming face, to the action which it exerts on the material of the object being produced and of the possibly different thickness that it has opposite different areas of the forming face.

The implementation of the method according to the invention thus makes it possible to optimize the working conditions of the tool, and consequently the quality of the object obtained by means of this tool.

In addition, whether a tool slice is produced in a foundry and then subjected to localized finishing machining or whether it is entirely produced by machining in a pre-existing block of a thermally conductive raw material, the machining operations can be carried out in a simpler and much less expensive than when it comes to performing machining on the parts of a tool made in a foundry in accordance with the prior art, since the implementation of the invention, in making it possible to machine slice by slice, generally makes it possible to limit machining to simple surfaces, in particular constituted by the junction faces, between which it is moreover easier to maintain a seal even during thermal expansion of the tool, and drilling and / or milling operations from these simple surfaces.

Thus, although it is in principle possible to give any desired conformation to the average surfaces of the elementary conduits, that is to say to the junction faces which coincide at least approximately with these average surfaces, it is preferred to the fullest extent of the possible to implement said initial step a of the method according to the invention by giving at least approximately planar shape to said average surfaces and to said junction faces, in which case, preferably, they are oriented respectively at least approximately parallel to each other if there is a plurality. The assembly of the different tool sections is also simplified, since this assembly can in this case be carried out by means acting on the end sections in a direction perpendicular to the different junction faces and clamping between these sections extreme the intermediate sections; among the means likely to be used for this purpose, mention may be made of the frets and the tie rods, these examples being in no way limiting. However, other modes of assembly of the tool slices can be chosen, in particular assembly modes, such as brazing, making it possible to choose freely the relative orientation of the average surfaces and of the junction faces, that is to say imposing no constraint in this respect, and providing without additional provision a seal between sections, that is to say a seal of the heat transfer fluid circuit, while it may be necessary to ensure this sealing by specific means such as seals reported when the mutual securing of the wafers is ensured by mutual tightening.

The first studies have shown that such an at least approximate flatness and an at least approximate mutual parallelism of the average surfaces of the first conduits will in most cases make it possible to optimally meet the needs for circulation of heat-transfer fluid in relation to the form of the forming face and with the needs in terms of heat exchanges between the heat transfer fluid and the object being formed, while simplifying the production of the tool slices and their assembly in a mutually juxtaposed state by the faces of junction.

The method according to the invention also makes it possible to conform in a particularly simple manner the or each second conduit as required while simplifying compliance with an optimal configuration, determined during the initial step a. Indeed, with a good approximation, we can allow each section of the second projected duct to be given, that is to say at each passage, a rectilinear or V shape, defined by two rectilinear branches offset angularly, particularly easy to perform as well by machining in the corresponding tool section as in foundry, it being understood that machining or production by coring in foundry makes it possible to comply with any changes in section and / or orientation of the or each second conduit, both between two sections only within a section, on the one hand, and that the mutual connection of sections or rectilinear passages slightly angularly offset or of rectilinear branches thus slightly angularly offset to respect a desired path of the or each second conduit does not have generally no disadvantage in terms of circulation of the heat transfer fluid.

In this regard, it is not departing from the scope of the present invention by providing an additional subdivision of a tool projected in slices having junction faces without grooves, that is to say not defining a first conduit when they are assembled by these junction faces. Such an additional subdivision can be chosen for example to facilitate the production of second projected conduits having changes in section and / or a non-rectilinear course, since it makes it possible to produce these second projected conduits by abutment of straight or V-shaped passages, possibly different section, arranged in respective tool sections, in a particularly simple manner both by machining and in foundry.

The most appropriate choice between the or each collector and the or each derivation as a first conduit, arranged approximately half in the junction faces of two adjacent tool sections, or as a second conduit, produced in the form of passages arranged in the mass of the tool sections, is within the normal abilities of a person skilled in the art and may vary depending on the shape of the object to be produced, namely more precisely of the shape of the forming face projected as a function of this shape of the object.

Thus, when, in the case of an object having the shape of a beam or a similar shape elongated in a determined longitudinal direction, the initial step a is implemented by giving the projected forming face an elongated shape according to a determined longitudinal direction, the initial step a is also implemented by orienting at least approximately longitudinally the or each projected manifold and at least approximately transversely the or each projected branch and the or each average surface and by choosing as first projected conduit the or each projected branch and as a second projected duct the or each collector, and step b is implemented by orienting at least approximately transversely the or each junction face and the or each groove and at least approximately longitudinally the or each passage. Then, the tool according to the invention is thus characterized in that the forming face has an elongated shape in a determined longitudinal direction, the or each junction face and the or each average surface are at least approximately transverse, the or each first conduit is at least approximately transverse and constitutes a bypass and the or each second conduit is at least approximately longitudinal and constitutes a manifold. In such a case, the or each collector most often has a generally linear shape, more or less rectilinear, and there are generally provided two copies, one of which is used for the arrival of the heat transfer fluid and the other for its return. and between which the or each branch forms a loop locally skirting the forming face.

When, on the other hand, in the case of an object having the shape of a pot or a similar shape, surrounding a determined longitudinal axis, the initial step a is carried out by giving the projected forming face a shape surrounding a determined longitudinal axis, the initial step a is also carried out by orienting at least approximately longitudinally the or each projected branch and at least approximately transversely the or each projected manifold and the or each average surface and by choosing as first projected conduit the or each manifold and as a second projected conduit the or each proposed diversion, and step b is implemented by orienting at least approximately transversely the or each junction face and the or each groove and at least approximately longitudinally the or each passage. Then, the tool according to the invention is characterized in that the forming face has a shape surrounding a determined longitudinal axis, the or each junction face and the or each average surface are at least approximately transverse, the or each first conduit is at least approximately transverse and constitutes a manifold and the or each second conduit is at least approximately longitudinal and constitutes a derivation. In such a case, the or each collector most often has a generally annular shape and there are generally provided two copies, one of which is used for the arrival of the heat transfer fluid and the other for its return and between which the or each derivation has a generally linear shape, more or less rectilinear.

These two examples correspond to frequent cases of application but are in no way limiting.

Other characteristics and advantages will emerge from the description below, relating to two nonlimiting examples of implementation of the invention, as well as from the appended drawings which accompany this description.

FIG. 1 shows a view of a punch intended for producing a part in the form of an axisymmetric pot by stamping a hot sheet, as well as a part view thus produced, during extraction of the punch, in section through a plane passing through a common axis of the punch and the part.

Figure 2 shows, in a sectional view similar to that of Figure 1, the corresponding matrix.

FIG. 3 shows a perspective view of the contour of a matrix according to the invention, intended for producing an elongated hollow beam, such as a bumper cross member for motor vehicles, by stamping a sheet metal hot, with illustration of the outline of the different sections of this matrix and illustration of the heat transfer fluid circuit inside it. Figure 4 shows a perspective view, similar to that of Figure 3, of one of the slices of this matrix, identified in IV in Figure 3;

FIG. 5 shows, in a view similar to that of FIG. 3, the corresponding punch and further illustrates the part produced by hot stamping by means of the matrix of FIG. 3 and the punch of FIG. 5, such as it occurs during extraction of the punch. Although the tools according to the invention which have been illustrated respectively in FIGS. 1 and 2 and in FIGS. 3 to 5 correspond to two cases of application of a tool according to the invention to the production of a part by stamping a hot sheet, a person skilled in the art will easily understand that one could produce in any similar way tools intended for the production of a part of the same respective shape by injection-molding of a thermoplastic material. The modifications to be made for this purpose to the tools which have been illustrated and which will be described relate to the normal skills of a person skilled in the art, an essential difference residing in the fact that the tools intended for injection-molding and corresponding respectively to the punch and to the die must define between them a closed cavity to receive the thermoplastic material whereas this condition does not have to be fulfilled between a punch and a hot stamping die.

Reference will firstly be made to FIGS. 1 and 2, where the part to be produced or produced has been designated by 1 and by 2 and 3 respectively the punch and the die used for this purpose. We have designated by 4 an axis longitudinal that the part 1, in the form of a pot, surrounds by presenting in this example a form of revolution around this axis 4, and there has been designated by the same reference an axis of symmetry of revolution respectively of the punch 2 and the matrix 3. A person skilled in the art will easily understand that the arrangements which will be described with regard to the punch 2 and the matrix 3, in relation to an axisymmetric part 1, can be adapted without difficulty to the case of a punch 2 and a matrix 3 intended for the production of a part 1 which, while having the general shape of a pot enveloping a longitudinal axis 4, have a shape different from a shape of revolution around this axis 4, while having a shape compatible with an embodiment by hot stamping; it would be the same if the tools constituted by the punch 2 and the matrix 3 in this example were intended for the production of the object 1 by injection-molding of a thermoplastic material. The shape of the object 1 and the shape, correlated, of the punch 2 and of the matrix 3 which will be described must therefore be considered as a simple illustration of the invention, without any limiting character as to the latter.

In the example illustrated, the object 1 has, in a single piece of sheet metal, a flat bottom 5, transverse and intersecting the axis 4, and an annular rim 6, longitudinal, surrounding the axis 4, bordering the bottom 5 and flaring from a curvilinear connection therewith.

More specifically, the rim 6 is delimited in this example, respectively towards the axis 4 and in the direction of a distance with respect thereto, by an inner peripheral face 7 and by a peripheral face outer 8 frustoconical of revolution around the axis 4, mutually parallel and flaring in a longitudinal direction 9 to a free edge 10 transverse, annular of revolution around the axis 4 and at least approximately planar and perpendicular to this axis 4. Opposite to direction 9, the faces 7 and 8 of the rim 6 are connected respectively to a flat inner face 11 of the bottom 5, by means of a concave curvature, and to a flat outer face 12 of this bottom 5, by means of a convex curvature, the two faces 11 and 12 being mutually parallel and perpendicular to the axis 4 which they intersect.

The punch 2 is intended to shape the inner faces 7 and 11 while the die 3 is intended to shape the outer faces 8 and 12, from a flat side, not shown, cut from a sheet of steel and heated to a suitable temperature, as is generally known in the field of hot stamping. The punch 2 and the die 3 are moreover intended to ensure, as is also known in this field, a soaking of the object 1 produced, by accelerated cooling by means of a circulation of a cooling fluid at l 'interior of the punch 2 and of the die 3, each of which internally comprises for this purpose a circuit 13, 14 for circulation of this fluid. As cooling fluid, water can be used, for example, but other fluids could be used, the nature of the heat transfer fluid circulating in a tool according to the present invention not being critical with regard to this- this. In relation to the shape of the interior faces 7 and 11 which it must shape, the punch 2 has in the illustrated example a generally frustoconical shape of revolution around the axis 4, this shape being defined by:

- a front face 15 turned in the opposite direction to direction 9 and complementary to the inner face 11 of the bottom 5, that is to say transverse, planar and intersecting the axis 4 at right angles, - an outer peripheral face 16 complementary to the inner peripheral face 7 of the rim 6, that is to say frustoconical of revolution about the axis 4 with a conicity identical to that of the face 7, this outer peripheral face 16 thus flares in the direction 9 from its curvilinear connection with the front face 15, which connection is convex and complementary to the concave curvilinear connection of the face 7 with the face 11, the external peripheral face 16 however having longitudinal dimensions greater than those of the internal peripheral face 7, and

another planar front face 17, perpendicular to the axis 4 and turned in direction 9, the external peripheral face 16 connecting to this front face 17 opposite, longitudinally, from its connection with the front face 15.

Thus, only a part of the peripheral face 16, namely its longitudinally closest part to the front face 15, is used for forming the inner peripheral face 7 of the rim 6 of the object 1 then that, during this forming, part of this face 16, adjacent to the face 17, remains exposed by the object 1.

The outline of the punch 2, with regard to the respective shapes and the relative arrangement of the front face 15 and the peripheral face 16, being determined as a function of the internal shape of the object 1 produced, as defined by the faces interior 7 and 11 thereof, the circuit 13 is designed, during the design of the punch 2, exclusively or practically exclusively as a function of a desired cooling effect of the object 1 in progress, by thermal conduction at through the material of the punch 2, from this circuit 13.

In the example illustrated, the circuit 13 includes a heat transfer fluid inlet pipe or manifold 18, arranged longitudinally and more precisely axially, having the shape of a blind hole opening into the front face 17 and closed in the immediate vicinity of the front face 15 by a transverse flat bottom 19. This collector 18 is delimited in the direction of a distance from the axis 4 by a first section of inner peripheral face 20 cylindrical of revolution around the axis 4 with a diameter determined not referenced, in its zone closest to the front face 17, and by a section 21 of inner peripheral face also cylindrical of revolution around the axis 4 but with a diameter slightly less than that of the section 20 in its zone the closer to the bottom 19, the two sections 20 and 21 being connected to each other by a flat shoulder 22, annular of revolution around the axis 4 and turned in the direction 9, at a longitudinal distance from the face 15 which corresponds substantially to the longitudinal distance mutually separating the free edge 10 of the rim 6 and the inner face 11 of the bottom 5 of the object 1 to be produced. In this respect, the longitudinal dimension of the section 21 is much greater than that of the section 20.

In close proximity to the bottom 19, the manifold 18 branches into eight bypass conduits 23 each of which is arranged in a respective mean half-plane defined by the axis 4 and which thus radiate radially with reference to this axis 4, with from a respective mouth in the inner peripheral face section 21 of the inlet manifold 18.

From this mouth into the inlet manifold 18, each of the bypass conduits 23 successively has:

a first rectilinear part 24 oriented radially with respect to the axis 4, that is to say in particular having a mean plane 29 perpendicular to this axis 4 and common to all the parts 24, and,

- From one end of the part 24 which is the furthest from the axis 4 while remaining set back towards the latter relative to the external peripheral face 26 of the punch 2, a respective rectilinear part, s '' moving away from its connection with part 24 along a respective axis 26 which progressively moves away from axis 4 in direction 9, forming with respect to axis 4 an unreferenced angle substantially identical to that which forms with respect to this axis the outer peripheral face of the punch 2, so that each of the parts 25 runs parallel to this face inner peripheral 16 inside the punch 2, as well as each part 24 runs parallel to the front face 15 of the tool 2 inside of it.

Each of the parts 24 and 25 has a circular current section, of the same diameter.

In contrast to its connection with the respective part 24, each part 25 is connected to an intermediate collector 27 also arranged inside the punch 2 and having, for its part, an annular shape of revolution around the axis 4, and more precisely toroidal in the example illustrated, with a circular section of diameter greater than that of the parts 24 and 25 and substantially identical to that of the section 20 of the inner peripheral face of the inlet manifold 18, that is to say slightly higher than that of the section 21 of the inner peripheral face thereof or even much higher than that of the parts 24 and 25.

The intermediate manifold 27 is disposed along a transverse mean plane 28 in which the shoulder 22 is also located, ensuring the connection between the sections 20 and 21 of the inner peripheral face of the manifold 18.

The intermediate collector 27 runs along the outer peripheral face 16 of the punch 2 in the same way as the part 25 of each bypass duct 23.

This intermediate manifold 27 is itself connected, by eight longitudinal conduits 30 cylindrical of revolution about respective longitudinal axes 31, parallel to the axis 4 and arranged in half-planes defined by this axis 4 and regularly distributed angularly around this one, to a collector of outlet or return 32 which has substantially the same shape as this intermediate collector 27 but is offset in the direction 9 relative to the latter, that is to say is located between this intermediate collector 27 and the front face 17 of the punch 2.

Preferably, the conduits 30 alternate, in circumferential direction around the axis 4, with the parts 25 of the branched conduits 23 to ensure optimal distribution of the heat transfer fluid inside the intermediate manifold 27, followed by an optimal passage towards the output collector 32.

The outlet manifold 32 is disposed in a transverse plane 33 thus offset towards the front face 17 of the punch 2 with respect to the transverse mean plane 28 of the manifold 27. In this same plane 33 is arranged a conduit 34 oriented radially with respect to the axis 4 and connecting the outlet manifold 32, in the direction of a distance with respect to the axis 4, to an outlet for the heat transfer fluid, located in the outer peripheral face 26 of the tool 2 but at the outside the area of this outer peripheral face 26 serving to form the inner peripheral face 7 of the rim 6 of the object 1.

In accordance with the present invention, once the circuit 13 is projected as a function of the thermal needs at the level of the external faces 15 and 16 of the punch 2, in particular as regards the bypass conduits 23, after the geometry of the faces has been projected 15 and 16 of the punch 2 as a function of the shape to be given to the inner faces 11 and 7 of the object 1, respectively, a subdivision of the punch 2 to be produced is projected. a plurality of sections which, in the example illustrated, are six in number respectively referenced 35, 36, 37, 38, 39, 40, oriented transversely with respect to axis 4 and successively longitudinally, in this order, in meaning 9.

The edge 35, or upstream end edge with reference to the direction 9, is delimited on the one hand by the front face 15 and the rounded connection thereof with the external peripheral face 16 of the punch 2, and on the other hand by a flat face 41 perpendicular to the axis 4, offset in the direction 9 with respect to the front face 15 and more precisely arranged along the mean plane 29, this face 41 constituting a junction face of the wafer 35 with the wafer 36 next in direction 9.

When the punch 2 is produced, this junction face 41 rests flat on a junction face 42 also flat, perpendicular to the axis 4 and arranged along the plane 29, which junction face 42 delimits the edge 36 in the direction opposite to direction 9. In this direction 9, the section 36 is delimited by a flat face 43, perpendicular to the axis 4 and constituting a junction face with the next section 37 in the direction 9. For this purpose, the section 37 is itself delimited in the opposite direction to direction 9 by a face 44 of junction with the edge 36, which face 44 is planar, perpendicular to the axis 4 and is applied flat on the face 43 when the tool 2 is realized.

In direction 9, section 37 is delimited by a flat face 45 perpendicular to axis 4 and serving as a junction with the following section 38 in direction 9, which is delimited in the opposite direction to direction 9 by a face 46 also flat and perpendicular to the axis 4, s' applying flat against the face 45 and thus constituting a junction face the edge 38 with the edge 37.

In the direction 9, the section 38 is delimited by a planar face 47 perpendicular to the axis 4 and arranged along the mean plane 28 of the manifold 27. This face 47 serves as a junction face with the following section 39 in the direction 9, which is delimited in opposite direction to direction 9 by a flat face 48, perpendicular to the plane 4 and arranged along the plane 28, this junction face 48 with the edge 38 being applied flat against the face 47 when the punch 2 is produced . In direction 9, the section 39 is delimited by a flat face 49 perpendicular to the axis 4 and located along the plane 33, which face 49 constitutes a junction face with the next section 40 in direction 9, which is delimited in opposite direction to direction 9 by a face 50 of junction with the edge 39, which face 50 is also plane, perpendicular to the axis 4 and arranged along the mean plane 33 of the collector 32 to be applied flat against the face 49 when the punch 2 is made. In direction 9, section 40, which constitutes the downstream limit section in direction 9, is delimited by face 17.

In the direction of a distance with respect to the axis 4, each of the sections 35, 36, 37, 38, 39, 40 is delimited by a respective annular section of the external peripheral face 16 of the punch 2 to be produced or realized, these sections of the peripheral face 16 are connecting each other to define the latter when the punch 2 is produced.

The faces 41 and 42 of junction between the sections 35 and 36 coinciding with the plane 29 which constitutes the mean plane of symmetry of the parts 24 of the different bypass conduits 23, each of these parts 24 is produced in half in each of these faces of junction 41 and 42, by fitting a respective groove 51, 52, of semi-circular section. When the sections 35 and 36, produced separately, are assembled by mutual application, flat, of the joining faces 41 and 42, the grooves 51 and 52 complement each other to form the respective parts 24.

In the section 36 are further arranged, along the axes 26, rectilinear passages 53 which thus cross the section 36 right through, longitudinally, that is to say from the junction face 42 to the junction face 43 , and constitute a respective section of a part 25 of each branch conduit 23.

Likewise, the wafer 37 is traversed longitudinally right through, along each of the axes 26, with a respective rectilinear passage 54 which opens into the junction faces 44 and 45 and corresponds to a section of part 25 of a conduit for lead 23 respective. It will be observed that no groove similar to the grooves 51 and 52 is arranged in the junction faces 43, 44, 45, and that it is the same in the junction face 46 of the wafer 38. On the other hand, in the face 47 of junction of the wafer 38 with the wafer 39, as well as in the face 48 at the junction of the wafer 39 with the wafer 38, which faces 47 and 48 coincide with the mean plane 28 of the manifold 27, a respective annular groove 55, 56 is provided, having a respective semicircular section and corresponding to a respective half of the manifold intermediate 27 as subdivided by its mean plane 28.

In addition is arranged in the section 38, along each axis 26, a respective longitudinal passage 57, rectilinear, opening on the one hand in the face 46 of junction with the section 37 and on the other hand in the groove 55 to form a part respective a section 25 of respective branch conduit 23.

Likewise, in each of the junction faces 49 and 50, which coincide with the mean plane 33 of the outlet manifold 32, are arranged on the one hand a respective annular groove 58, 59 of semicircular section, corresponding to one half of this manifold outlet 32 as subdivided by its mean plane 33, and on the other hand a rectilinear groove 60, 61, radial with reference to axis 2 and corresponding to a respective half of the outlet 34 as subdivided by the mean plane 33 .

When the different sections are assembled, the grooves 55 and 56 complement each other to form the intermediate collector 27, the grooves 58 and 59 complement each other to form the outlet collector 32 and the grooves 60 and 61 complement each other to form the outlet 34.

In addition, in the section 39 are arranged, along the axis 31, two longitudinal passages each of which integrally constitutes a respective conduit 30 and connects mutually the grooves 56 and 58 arranged respectively in the junction faces 48 and 49 of this section 39.

Furthermore, each of the sections 35 to 40 defines, by a respective longitudinal, axial passage 62, 63, 64, 65, 66, 67, a respective section of the inlet manifold 18. In this respect, the passage 62 is blind, arranged in a hollow in the connecting face 41 of the section 35 and it is delimited on the one hand in the direction opposite to the direction 9 by the bottom 19, set back with respect to the junction face 41 in the direction opposite to the direction 9, and on the other hand in the direction of a distance with respect to the axis 4 by a corresponding part of the inner peripheral face section 21 of the manifold 18. The sections 63, 64, 65, respectively cross the sections 36, 37, 38 right through and correspond to a respective part of the section 25 of the inner peripheral face of the inlet manifold 18. The passages 66 and 67 pass through right through respectively the section 39 and the section 40 and correspond to a respective part of section 20 of the peripheral face that inside the inlet manifold 18; in other words, they have with reference to the axis 4 a diameter greater than that of the passages 62, 63, 64, 65, the shoulder 22 being defined by a marginal zone of the junction face 47 of the wafer 38 , around the mouth of passage 65 in this face.

Once the punch 2 projected intellectually subdivided into the different sections 35 to 40, with the respective grooves and passages corresponding to parts of the projected circuit 13, these sections 35 to 40 are produced independently of each other, ie in foundry work with the corresponding grooves and / or passages, either by machining a respective preexisting block of a thermally conductive material, preferably chosen from the abovementioned materials when it comes to making a punch 2 for hot stamping ; in this regard, it is advantageous to use the cupro-Al ₂ 0 ₃ sold under the registered trademark GLIDCOP, under the references A115, A125 and Al60, by the company OMG AMERICA, which have high values in terms of elastic limit at 2% MPa and in terms of thermal conductivity, or cupro-cadmium, which also have good characteristics in this regard, these materials being however indicated only by way of nonlimiting example. Once the slices 35 to 40 thus produced either in the foundry or by machining, they are assembled together by mutual application, flat, of their joining faces 41 to 49, which constitutes the punch 2. This assembly can be carried out by different means, as indicated above, but it will be observed that the aforementioned materials lend themselves well to soldering which makes it possible at the same time to seal the circuit 13.

When the faces 15 and 16 intended to be used for forming the object 1 have a simple conformation, as illustrated, each of sections 69, 70, 71, 72, 73 can be produced in such a way that it has its conformation final at a respective useful face intended to constitute the face 15 or a respective section of the face 16; then we obtain directly the faces 15 and 16 of the tool 1 by mutual assembly of the slices. When, on the other hand, the faces intended for forming have a more or less complex shape, it may be preferable to produce on each wafer only the blank of a useful face, in which case only a blank is obtained during assembly. of the forming face and the assembly of the wafers is followed by a machining of this blank, in order to produce the forming face.

The matrix 3 is designed according to a similar intellectual approach, characteristic of the present invention, and is composed in the illustrated example of six sections 73 to 74 which follow one another longitudinally in the direction 9 of the axis 4 and are joined mutually to the mutually joined state by mutual junction faces 73 to 84 planes, perpendicular to the axis 4 and turned alternately in direction 9, as regards the faces 75, 77, 79, 81, 83, delimiting in this direction respectively the sections 69, 70, 71, 72, 73, and in the opposite direction to the direction 9 with regard to the faces 76, 78, 80, 82, 84, which respectively delimit the sections 70, 71, 72, 73, 74 in the opposite direction to the direction 9. The section 69, in the opposite direction 9, and the section 74, in the direction 9, are further defined respectively by a free face 85, 86 plane, perpendicular to the axis 4 and rotated respectively in opposite direction to direction 9 and in this direction 9, these faces 85 and 86 constituted nt of the external peripheral faces of the matrix 3.

Furthermore, in the direction of a distance with respect to the axis 4, the matrix 3 is delimited by an external peripheral face 87 which is for example cylindrical of revolution around the axis 4 and whose each section 69 to 74 forms a part, by a respective external peripheral face not referenced. This shape of the face 87 is, however, indifferent with regard to the forming of the object 1. Around the axis 4 and towards it, the matrix 3 defines a cavity 107 for hot stamping for the object 1 to be produced. , which cavity 107 is longitudinal and opens into the face 86 in the direction 9, while it is closed towards the face 85 in the opposite direction.

More specifically, the cavity 107 is delimited, in the direction of a distance with respect to the axis 4, by an inner peripheral face 88 frustoconical of revolution around the axis 4, flaring in the direction 9 with a taper identical to that of the outer peripheral face 8 of the rim 6 of the object 1 to be produced, between two geometric planes 89 and 90 perpendicular to the axis 4 and passing respectively inside the section 74, between the faces 84 and 86 thereof, and inside the section 71, between the faces 78 and 79 thereof and respectively closer to the face 84 than the face 86 and closer to the face 79 than the face 78. Between the plane 89 and the face 86, the inner peripheral face 88 of the cavity 107 widens even more, along a curvilinear profile, to facilitate the engagement of the sheet in the cavity 107 during stamping. Longitudinally opposite to its connection with the face 86, in the opposite direction to the direction 9, the inner peripheral face is connected, at the plane 90, to a plane inner face 91, perpendicular to the axis 4 and complementary to the outer face 12 of bottom 5 of the object 1 to be produced, the connection being curvilinear in a complementary manner to the mutual connection of the external peripheral face 8 of the rim 6 of the object 1 to be produced and of the external face 12 of the bottom 5 thereof.

The bottom face 91 of the cavity 107, its curvilinear connection with the face 88 and a section thereof are hollowed out in the face 79 of the section 71 and the rest of the face 91 is divided into sections between the sections 72, 73, 74 which, for this purpose, are drilled right through, axially, with a respective passage 92, 93, 94, while the wafer 71 is pierced with a blind axial hole 95 in its face 79 for constitute the bottom face 91, the corresponding part of the outer peripheral face 88 and their curvilinear mutual connection.

The circuit 14 for circulation of heat transfer fluid, namely a cooling fluid such as water in this example, is essentially arranged in sections 71, 72, 73, 74, around the cavity 107 and comprises two transverse collectors 96, 97, annular of revolution about the axis 4 and of the same circular section, arranged coaxially along the same transverse mean plane 98 along which the junction faces 77 and 78 are arranged between the sections 70 and 71. These collectors 96 and 97, respectively of inlet and outlet of heat-transfer fluid, are disposed respectively in the immediate vicinity of the outer peripheral face 87 of the matrix 3 and in the immediate vicinity of a geometric extension of the inner peripheral face 88 of the cavity 107, and each of them is defined for half by a respective annular groove 98, 99 arranged in the junction face 77 of the wafer 70, and for half by a respective annular groove 100, 101 arranged in the junction face 78 of section 71, the two halves of each collector 96, 97 being defined by the mean plane 98.

Similarly, an intermediate manifold 102, transverse, annular of revolution around the axis 4 and of circular section here slightly greater than that of the collectors 96 and 97, is arranged along a mean plane 103 perpendicular to the axis 4 and along which the junction faces 83 to 84 of the sections 73 and 74 are arranged, between the inner peripheral face 88 of the cavity 107 and the outer peripheral face 87 of the matrix 3, near the mouth of the cavity 107 in the face 86 of the section 74. The collector 102 is also produced in half in the form of an annular groove 104 arranged in the junction face 83 of the section 73 and in the form of an annular groove 105 arranged in the junction face 84 of tranche 94.

According to mean half-planes defined by axis 4 and angularly distributed around it, here eight in number, pairs of bypass conduits are arranged between the intermediate collector 2 and the inlet 96 and outlet collectors 97, each of these pairs comprising a rectilinear conduit 108, of axis 109 parallel to axis 4, mutually connecting the inlet manifold 96 and the intermediate manifold 102 along the inner peripheral face 87 of the matrix 3, and a rectilinear conduit 110, of longitudinal axis 111 but having an obliquity such that this conduit 110 runs along the outer peripheral face 88 of the cavity 107 by mutually connecting the intermediate manifold 102 and the outlet manifold 96. Each of the conduits 108 and 110, of the same circular section, have a smaller diameter than that of the collectors 96, 97 and 102.

In application of the present invention, each of the conduits 108 and 110 is formed from the alignment, along the respective axis 109, 110, of a passage 112, 113 arranged along the respective axis 109, 111 in the section 71 and opening on the one hand through the groove 100 or 101 and on the other hand in the junction face 79, of a respective passage 114, 115 arranged along the respective axis 109, 111 in the section 72 and crossing the latter of right through, that is to say from its face 80 to its face 81, and a respective passage 115, 116 arranged along the respective axis 109, 111 in the section 73 and opening on the one hand into the face 82 thereof and on the other hand in the groove 104 defining half of the intermediate manifold 102.

In addition, respectively for the arrival and return of the heat transfer fluid, in the section 70 are arranged two rectilinear passages 117, 118 of respective axis 119, 120 parallel to the axis 4, the passage 117 opening on the one hand into the groove 98 defining half of the inlet manifold 96 and on the other hand in the junction face 76 while the passage 118 opens on the one hand into the groove 99 defining half of the outlet manifold 87 and on the other hand in this same face 76. Along the same axis 119, 120, the section 69 is pierced right through, that is to say between its faces 75 and 85, with a respective rectilinear passage 121, 122 which has the same circular section that the passage 117, 118 respectively corresponding, the diameters of the different passages 117, 118, 121, 122 being identical and intermediate between the respective diameters of the collectors 96, 97, 102, on the one hand, and the bypass conduits 108, 110 , on the other hand. A person skilled in the art will readily understand that the various sections 69 to 74 can be produced, like the sections 35 to 40 of the punch 2, in foundry or by machining a pre-existing block of a thermally conductive material, for example chosen from the range previously indicated, the mutual assembly of the wafers 69 to 74 can also be achieved by one or the other of the aforementioned means, namely preferably by brazing in order to directly provide a seal to the circuit 14 for circulation of heat transfer fluid. Likewise, each of the sections 71 to 74 which together define the cavity 107 may present from its manufacture, respectively around the blind hole 95 or the corresponding passage 92, 93, 94, a useful face having the final geometry of a respectively corresponding part of the bottom 9 or of the inner peripheral face 88 of the cavity 107, but it can also be provided that each of the sections 71 to 74 has, during its manufacture, only a blank of such a useful face, and that the faces 91 and 88 are machined only after the slices have been assembled. It is understood that the punch 2 and the die 3 for hot stamping which have just been described cooperate in the manner known in the prior art with a flat side cut from a suitable sheet metal then heated, to form the object. 1 then cool it for the purpose of soaking it, so that the mode of use of the punch 2 and of the die 3 will not be described.

Likewise, the conformation of each of the circuits 13, 14 for circulation of a heat-transfer fluid respectively inside the punch 2 and of the matrix 3, will not be described further, for example in terms of section of these circuits 13 and 14 according to their areas, the most appropriate choices that can be made by those skilled in the art, and this independently of any limitation similar to that which was opposed in the prior art by the foundry methods used, and that each of the characteristic slices of the implementation of the present invention is carried out in a foundry or by machining a preexisting block of an appropriate material. Likewise, the shape of the cooling circuits 13 and 14 best suited to each geometry of the object 1 to be produced and to the geometry presented by the faces of the punch and of the matrix useful for this purpose will, in each case, be subject to aptitudes. normal of a skilled person.

In this respect, FIGS. 3 to 5, to which reference will now be made, illustrate a punch and a die which, while being suitable for producing, for example by hot stamping, an object having a conformation totally different from that of object 1 which has just been described, the punch, the matrix and the heat transfer fluid circuits which they contain themselves having for this purpose very different conformations, have the subdivision into mutually mutually assembled slices, characteristic of the present invention.

Figures 3 to 5 thus illustrate a punch 124 and a die 125 intended to cooperate to form by hot stamping, from an initially flat side cut from a sheet, an object 126 in the form of an elongated beam in a longitudinal direction 127 , which will serve as a reference for the description of this object 126 as for the description of the punch 124 and of the matrix 125. More precisely, the object 126 has a double curvature in this example, namely a curvature following a first plane of symmetry 128 which is longitudinal as well as, generally, a curvature along transverse planes and, in particular, along a transverse plane of symmetry 129. The object 126 is thus delimited by an external face 130 with double convex curvature, by a face interior 131 with double concave curvature, and by a peripheral edge 132 mutually connecting these two faces 130 and 131 which are approximately homothetic if we except certain localized thickness variations which may result from the application of the stamping to a flank of initially uniform thickness.

Like the longitudinal direction 127, the mean planes of symmetry 128 and 129 will serve as a reference to the description, which will follow, of the punch 124 and of the matrix 125, of which these planes also constitute respectively a mean longitudinal plane of symmetry and a mean transverse plane of symmetry.

As they are projected and then produced, the punch 124 and the die 125 have an outer contour comprising in particular a respective face for forming the object 126, namely respectively a face 133 for forming the inner face 131 and a face 134 for forming the external face 130, which faces 133 and 134 respectively have a shape complementary to that of the face 131 and a shape complementary to the face 130.

Around the respective forming face 133, 134, the punch 124 and the matrix 125 are delimited externally by a sidewalk 135, 136 bordering on all sides this forming face 133, 134 in the direction of a distance from the planes 128 and 129, each of these sidewalks 135, 136 being defined by generatrices perpendicular to the plane 128, from its connection to the respective forming face 133, 134. In the direction of a distance from the planes 128 and 129, the sidewalks 135 and 136 are connected to a respective external peripheral face 137, 138 set back with respect to the respectively corresponding sidewalk and to the respectively corresponding forming face and defined by generatrices parallel to the two planes 128 and 129.

Opposite their connection with the respective sidewalk 135, 136, the outer peripheral faces 137, 138 are connected to a flat back 139, 140, perpendicular to the two planes 128 and 129 and turned opposite to the forming face. respectively 133, 134 and respective sidewalk 135, 136. The connection of the external peripheral face 138 to the back 140 is direct in the case of the matrix 125, while the connection of the external peripheral face 137 to the back 139 is effected by means of a peripheral rim 141 in the case of the punch 124.

It will be observed that only the shape of the forming faces 133 and 134 and, in part, the sidewalks 135, 136 which border them respectively is of importance in the forming of the object 126 by hot stamping, so that the outline of the punch 124 and the matrix, 125 is otherwise indifferent in this regard.

As they are projected, the punch 124 and the die 125 internally comprise a respective circuit 142, 143 for the circulation of a heat transfer fluid, such as cooling water for the purposes of soaking the object 126 stamped at hot, and this respective circuit 142, 143 is projected as a function of the cooling requirements of the object 126, respectively at its faces 131 and 130, these requirements being able to vary according to the zones of the object 126.

In the example illustrated, each of the circuits 142, 143 thus comprises two collectors of respective general longitudinal orientation, arranged largely recessed in the mass of the punch 124 and of the matrix 125, respectively, relative to the respective sidewalk 135, 136. Thus, the circuit 142 of the punch 124 comprises two approximately longitudinal collectors 144, 145 parallel to the plane 128 and mutually symmetrical with respect to it, one of which serves as a collector inlet of the heat transfer fluid and the other of return manifold of this heat transfer fluid, and the circuit 143 comprises two approximately longitudinal manifolds 146, 147 also parallel to the plane 128 and mutually symmetrical with respect thereto, one of which serves as an inlet manifold and the other as a return manifold for the heat transfer fluid.

More specifically, each of the collectors 144 and 145 is subdivided longitudinally, in the example illustrated, into five elementary collectors, mutually insulated against a circulation of fluid from one to the other, at the rate of two collectors longitudinally extreme, respective elementaries which are furthest from plane 129, of a respective longitudinally central elementary collector, which straddles plane 129, and of two respective longitudinally intermediate elementary collectors each of which connects a longitudinally central elementary collector to a longitudinally collector respective respective. This subdivision takes account of specific cooling needs of the object 126 and may not exist, or exist in a different form, in the case of objects 126 shaped differently.

For the arrival of heat transfer fluid in each of the elementary collectors which constitute it, the inlet manifold 144 has a bypass, at each of the elementary collectors which constitute it, a pipe 148 for the arrival of heat transfer fluid, which pipe 148 connects this elementary collector to the back 139 of the punch 124, parallel to the two planes 128 and 129. Likewise, each collector elementary constituting the return collector 145 has a bypass 149 which connects it to the back 139 of the punch 124, parallel to the two planes 128 and 129. In addition, two elementary collectors which correspond by mutual symmetry with respect to the plane 128 are connected mutually by at least one, and preferably several bypass conduits 150 each of which has a transverse mean plane 154, that is to say perpendicular to the direction 127 and parallel to the plane 129, and symmetrically overlaps the plane 128 along the closer the sidewalk 135 and the forming face 133. Thus, by way of nonlimiting example, two conduits 150 have been illustrated connecting two longitudinally extreme elementary collectors, forming respectively part of the inlet manifold 144 and the return manifold 145 , four conduits 150 connecting the two longitudinally central elementary collectors and four conduits 150 rac mutually stringing two longitudinally intermediate elementary collectors, respectively forming part of the inlet manifold 144 and the return manifold 145, the conduits 150 being mutually symmetrical with respect to the plane 129 like the object 126.

In the case of the matrix 125, each of the collectors 146, or coolant inlet manifold, and 147, or coolant return manifold, is subdivided longitudinally into three elementary collectors isolated from one another. with respect to a circulation of heat-transfer fluid, at a rate of two longitudinally extreme elementary collectors, mutually symmetrical with respect to the plane 129, and a longitudinally central or intermediate elementary manifold, symmetrically overlapping the plane 129. Each of these elementary collectors has a conduit which connects it to the back 140 of the matrix 125 parallel to the two planes 128 and 129, at the rate of a pipe 151 for the arrival of heat transfer fluid respectively for each elementary collector constituting the inlet manifold 146, and a pipe

152 return of heat transfer fluid for each of the elementary collectors constituting the return collector 147.

In addition, two elementary collectors which correspond by mutual symmetry with respect to the plane

128 are connected to each other by at least one bypass duct 153 which symmetrically overlaps the plane 128, as close as possible to the sidewalk 136 and the forming face 134; in the nonlimiting example illustrated, four of these bypass conduits 153 mutually connect the longitudinally extreme elementary collectors which correspond by mutual symmetry with respect to the plane 128, and seven of these bypass conduits 153 mutually connect the two longitudinally central elementary collectors or intermediates, each of these bypass conduits

153 being located along a respective mean plane 155 transverse, that is to say perpendicular to the direction 127. The circuits 142 and 143 being thus projected, the punch 124 projected and the die 125 are decomposed projected into a plurality of sections 156, 157 each of which is delimited in particular by at least one face, and in a current manner by two faces 160, 161 of junction with an immediately adjacent slice, which faces 160, 161 of junction coincide with the plane means 154, 155 of a respective branch conduit 150, 153. Each of the sections 156 of the punch 124 is moreover delimited by a corresponding section of the forming face 133, of the sidewalk 135, of the outer peripheral face 137 and of the back 139, just as each section 157 of the matrix 125 is moreover delimited by respective sections of the forming face 134, of the sidewalk 136, of the outer peripheral face 138 and of the back 140. With the exception of the longitudinally extreme sections 156, 157, which have a single junction face, these sections respective are delimited by their connection to two respective junction faces, delimiting the same section 156 or 157. According to the present invention, each section 156, 157 is produced independently of the other sections, for example in foundry or by machining in a preexisting block of a thermally conductive material chosen for example from the aforementioned materials, in a manner which has been illustrated in FIG. 4 in connection with a longitudinally intermediate slice 138 of the matrix 125 and can be easily transposed to each of the longitudinally intermediate slices 156 of the punch 124, so as to present: - in each junction face 160, which coincides at least approximately with a mean plane 155, a throat respective 162 corresponding at least approximately to one half of a branch conduit 153 as subdivided by its mean plane 155, and

- In the mass of wafer 157, two passages or sections of collectors 158, 159, which cross wafer 157 right through, that is to say from one to the other of its junction faces 160 , to which each of the grooves 162 is connected and which respectively constitute a section of an elementary manifold of the inlet manifold 146 and a section of an elementary manifold of the return manifold 147.

In the case of longitudinally extreme sections 157, comprising a single junction face 160, and consequently a single groove 162, the sections 158 and 159 of the manifold are blind, that is to say open exclusively in this junction face 160 .

It will be observed in FIG. 4 that the implementation of the present invention makes it possible to communicate easily to each groove 162, that is to say to each bypass duct 153, for example by milling in the corresponding junction face 160, a section evolving in any desired manner, the groove 162 thus having a widening 163 located around the mean longitudinal plane of symmetry 128. We will also observe in FIG. 3, with reference to the elementary collectors longitudinally extreme, and more precisely at their ends closest to the elementary collectors longitudinally central or intermediate, that each section 158 and 159 of manifold can not only be straight and produced for example by drilling from one or the other of the junction faces 160, but also have a V shape, defined by two rectilinear branches mutually angularly offset and produced for example by drilling from each of the junction faces 160. Depending on their position, the conduits 151 for the arrival of heat transfer fluid and 152 for the return of fluid coolant can be arranged in the mass of a corresponding wafer 157, to lead into the section 158 or the section 159 of the collector, respectively; if they are arranged at least approximately along a mean plane 155 corresponding to a bypass duct 153, they can also be arranged like this bypass duct by half in two junction faces 160, belonging to mutually adjacent sections 157.

During the mutual assembly of the wafers 157, applied to each other flat by their junction faces 160, the grooves 162 complement each other from one wafer 157 to the other to constitute the bypass conduits 153 as well as the sections 158 and 159 , respectively, complement each other from one section 157 to the other to constitute the elementary collectors of the inlet manifold 146 and the return manifold 147 and, where appropriate, the same is true of the constituent halves of each conduit 151 or 152, which constitutes the circuit 143. A seal around it can be obtained by any appropriate means, as can the integral assembly of the wafers 157, mutual brazing of the wafers 157 being preferred in this regard if their constituent material lends itself to it insofar as such brazing makes it possible to obtain both mutual joining and sealing of the circuit 143.

In a similar way, that a person skilled in the art will easily deduce from what has just been described with respect to the matrix 125, with reference to FIGS. 3 and 4, the circuit 142 of the punch 124 is formed, during the mutual assembly of the wafers 156, on the one hand by grooves which, arranged in their junction faces 161 coinciding at least approximately with the mean planes 154, complement each other to constitute the bypass conduits 150 and, where appropriate, the conduits 148 and 149 which can also be arranged in the mass of the wafers 156, and on the other hand by passages constituting sections of the collectors 144, 145, which are arranged through the wafers 156, except as regards the longitudinally extreme wafers in which these sections are blind, and complement each other to constitute the elementary collectors constituting the collectors 144 and 145, respectively. When, as described, each collector

144, 145, 146, 147 is formed of several elementary collectors which are mutually independent as regards the circulation of the heat-transfer fluid, those of the sections 156 and 157 which correspond to the transition between two elementary collectors can be devoid of passage or through section such that 158 and 159, or provided with such sections in blind form in order to avoid any fluidic communication between the various elementary collectors constituting the same collector, as a person skilled in the art will readily understand. As a person skilled in the art will also readily understand, the forming faces 133 and 134 can be, also in the case of the punch 124 and of the die 125, machined after assembly of the different sections 156, 157, from a blank of forming face constituted by blanks of useful face of each wafer 156, 157; each wafer 156, 157 may also have, from its manufacture, a useful face having the final conformation of a section of forming face 133, 134, in which case the forming faces 133, 134 are formed by these useful faces, directly, during the assembly of the sections 156, 157. The same applies to the sidewalks 135 and 136.

Such a person skilled in the art will easily understand that, although the subdivision of a tool such as a punch 2 or 124 or a matrix such as 3 or 125 into slices delimited by faces of mutual junction parallel to each other is preferred, and may correspond to a conformation of the circuit 13, 14, 143, 144 generally satisfactory in most cases, that is to say for most of the shapes of objects 1 or 126 to be produced by hot stamping or, in a non- represented but easily understood by a person skilled in the art, by injection-molding of a thermoplastic material, other modes of subdivision, imposed by a more appropriate conformation of the heat-transfer fluid circuit, could be chosen without going out of the framework of the present invention, these modes of subdivision being able to result in the junction faces between sections, coinciding at least approximately with the average surfaces of certain conduits cons circuit members heat transfer fluid, are not parallel to each other, or even have a shape different from a planar shape.

A person skilled in the art will also easily transpose the provisions which have been described with reference to hot stamping tools to the production of thermoforming tools, with no fundamental difference as regards the design of these tools, the cooling fluid. being simply replaced by a heating fluid, or tools for injecting thermoplastic material into a molding cavity, the essential difference consisting in the fact that the mold parts corresponding respectively to the punch and to the die which have been described must , in a closed position of the mold, be mutually contiguous around an imprint which they delimit by their faces corresponding to the forming faces described, whereas this is not necessarily the case when it is a punch and a matrix at the end of the relative movement of hot stamping.

In general, the subject of the present application is susceptible of numerous variants, adapted to each form of objects to be produced and to the way in which the tools work to form these objects, without thereby leaving the scope of this invention as defined by the appended claims.

Claims

1. Method for producing a tool (2, 3, 124, 125) intended for forming a material, in particular by hot stamping or injection-molding, for the purpose of making it an object (1, 126) of defined shape, said tool 2, 3, 124, 125) having for this purpose a forming face (16, 88, 133, 134) of complementary shape of at least a part of said determined shape, said method comprising a initial step a consisting of projecting a contour of the tool 2, 3, 124, 125) to be produced, comprising a projected forming face having said complementary shape, and to design inside said projected contour, as a function of said shape complementary, a circuit (13, 14, 142, 143) projected for circulation of a heat transfer fluid inside the tool 2, 3, 124, 125) to be produced, said circuit (13, 14, 142, 143 ) projected comprising a plurality of conduits (18, 23, 27, 30, 32, 96, 97, 102, 108, 115, 144, 145, 146, 147, 150, 153) projected d have at least one constitutes a collector (18, 27, 32, 96, 97, 102, 144, 145, 146, 147) projected and at least one of which constitutes a bypass (23, 108, 115, 150, 153 ) projected from the collector (18, 27, 32, 96, 97, 102, 144, 145, 146, 147) projected and runs along the projected forming face (16, 88, 133, 134), characterized: - in that l '' the initial step a is implemented by having at least one first conduit (24, 27, 32, 96, 97, 105, 150, 153) projected along an average surface (28, 29, 33, 98, 103, 154, 155) as simple as possible, the average surface (28, 29, 33, 98, 103, 154, 155) of the or each first duct (24, 27, 32, 96, 97, 105, 150, 153) projected being secant from the face of projected forming (16, 88, 133, 134), by defining sections of projected forming face (16, 88, 133, 134) therein, and at least one second conduit (18, 25, 108, 115, 144 , 145, 146, 147) projected, by defining therein sections of the or each second conduit (18, 25, 108, 115) projected, and - in that the method then comprises the succession of the steps consisting in:

"b: make tool slices (35, 36, 39, 40,

71, 73, 74, 156, 157) each of which is delimited in particular by at least one junction face, at least certain junction faces (41, 42, 47, 48,

49, 50, 77, 78, 83, 84, 160, 161) reproducing at least approximately an average surface (28, 29,

33, 98, 103, 154, 155) respectively, namely commonly by two junction faces (48, 49, 160, 161) reproducing at least approximately respectively one and the other of two medium surfaces (28, 33, 154, 155) respectively, and by at least one blank of a useful face reproducing a respective section of projected forming face (16, 88, 133, 134), adjacent to said average surface

(28, 33, 154, 155) respective, namely commonly a section of forming face (16, 88, 133,

134) projected delimited by said two average surfaces (28, 33, 154, 155) respective, and comprises on the one hand, in its mass, a passage (53, 57, 62,

63, 112, 113, 115, 116, 158, 159) reproducing the respective section of the or each second conduit (18, 25, 108, 115, 144, 145, 146, 147) projected and opening into the or each junction face (41, 42, 47, 48, 49, 50, 77, 78, 83, 84) and on the other hand, in the or each junction face (41, 42, 47, 48, 49, 50, 77, 78, 83, 84), a groove (51, 52, 56, 58, 59, 96, 97, 100, 104, 105, 157) branched into said passage (53, 57, 62, 63, 112, 113, 115, 116, 158, 159) and reproducing at least approximately one half of the first duct (24,

27, 32, 96, 97, 105, 150, 153) projected respectively,

"c: juxtapose the tool edges (35, 36, 38, 39,

40, 70, 71, 73, 74, 156, 157) by their junction faces (41, 42, 47, 48, 49, 50, 77, 78, 83, 84) and secure them mutually in a relative position in which the useful faces or said blanks, the passages (53, 57, 62, 63, 112, 113, 115, 116, 158, 159) and the grooves (51, 52, 55, 56, 58, 59, 96, 97, 100, 101, 104, 105, 157) are completed from one edge (35, 36, 38, 39, 40, 70, 71, 74, 156, 157) to the other to respectively constitute the forming face or a blank for the forming face (16, 88, 133, 134), the or each second conduit (18, 25, 108, 115, 144, 145,, 146, 147) and the or each first conduit (24, 27, 32 , 96, 97, 105, 150, 153), and if necessary, machine the forming face blank to produce the forming face (16, 88, 133, 134).

2. Method according to claim 1, characterized in that said initial step is implemented by giving an at least approximately planar shape to the or each average surface (28, 29, 33, 98, 154, 155) and at or each junction face (41, 42, 47, 48, 49, 50, 77, 78, 83, 84, 150, 161) .

3. Method according to claim 2, characterized in that, in the case of a plurality of said average surfaces (28, 29, 33, 98, 103, 154, 155) and said junction faces (41, 42, 47, 48, 49, 50, 77, 78, 83, 84, 160, 161), said initial step (a) is implemented by orienting respectively said average surfaces (28, 29, 33, 98, 103, 154, 155) and said junction faces (41, 42, 47, 48, 49, 50, 77, 78, 83, 84, 160, 161) at least approximately parallel to each other.

4. Method according to any one of claims 1 to 3, characterized in that said initial step is implemented by giving each section of second conduit (18, 25, 108, 115, 144, 146, 147) projected a rectilinear shape or a V shape defined by two rectilinear branches offset angularly.

5. Method according to any one of claims 1 to 4, characterized in that when, in the case of an object (126) having the shape of a beam or a similar shape elongated in a determined longitudinal direction (127) , the initial step (a) is implemented by giving the projected forming face (133, 134) an elongated shape in a determined longitudinal direction, the initial step is also implemented by orienting at least approximately longitudinally the or each collector (144, 145, 146, 147) projected and at least approximately transversely the or each bypass (150, 153) projected and the or each surface (154, 155) average and by choosing as first conduit (150, 153) projected the or each branch (154, 155) projected and as second conduit (144, 145, 146 , 147) projected the or each collector (144, 145, 146, 147), and step b is implemented by orienting at least approximately transversely the or each junction face (160, 161) and the or each groove (157) and at least approximately longitudinally the or each passage (158, 159).

6. Method according to any one of claims 1 to 4, characterized in that when, in the case of an object (1) having the shape of a pot or a similar shape, surrounding a determined longitudinal axis (4) , the initial step a is carried out by giving the projected forming face (16, 88) a shape surrounding a determined longitudinal axis (4), the initial step is also carried out by orienting at least approximately longitudinally the or each branch (25, 108, 115) projected and at least approximately transversely the or each collector (27, 32, 96, 97, 102) projected and the or each average surface (28, 33) and choosing as the first conduit (27, 32, 96, 97, 102) projected the or each collector (27, 32, 96, 97, 102) projected and as a second conduit (25, 108, 115) projected the or each branch (25, 108, 115 ) projected, and step b is implemented by orienting at least approximately transversely the or each junction face (47, 49, 77, 83, 84) and the or each groove (55, 56, 58, 59, 96, 97, 100, 104, 105) and at least approximately longitudinally the or each passage (53, 57, 112, 113, 115, 116).

7. Method according to any one of claims 1 to 6, characterized in that the tool edges are produced (35, 36, 37, 38, 39, 40, 69, 70, 71, 72, 73, 74, 156, 157), during step b, by machining in a pre-existing block of thermally conductive raw material.

8. Method according to claim 7, characterized in that said raw material is chosen from a group comprising cupro-Al ₂ 0 ₃ , cupro-cadmium, cupro-beryllium and stainless steels.

9. Tool for forming a material, in particular by hot stamping or injection-molding, for the purpose of making it an object (126) of determined shape, said tool (2, 3, 124, 125) having this effect a forming face (16, 88, 133, 134) of shape complementary to at least a part of said determined shape and an internal circuit (13, 14, 142, 143) for circulation of a heat-transfer fluid, said circuit (13, 14, 142, 143 comprising a plurality of conduits (18, 23, 27, 30, 32, 96, 97, 102, 108, 115, 144, 145, 146, 147, 150, 153) of which at least one constitutes a collector (18, 27, 32, 96, 97, 102, 144, 145, 146, 147) and at least one of which constitutes a derivation (23, 108, 115, 150, 153) of the collector ( 18, 27, 32, 96, 97, 102, 144, 145, 146, 147) and runs along the forming face (16, 88, 133, 134), characterized in that it consists of an assembly integral with tool edges (35, 36, 38, 39, 40, 70, 71, 73, 74, 156, 157) mutually juxtaposed by joining faces, at least some of which (41, 42, 47, 48, 49, 50, 77, 78, 83, 84, 160, 161) coincide at least approximately with an average surface (28, 29, 33, 98 , 103, 154, 155), as simple as possible, of a first conduit (24, 27, 32, 96, 97, 105, 150, 153) and which are intersecting from the forming face (16, 88, 133 , 134), by defining sections of the forming face, and at least one second duct (18, 25, 108, 115, 144, 145, 146, 147), by defining sections of second duct therein.

10. Tool according to claim 9, characterized in that the or each junction face (41, 42, 47, 48, 49, 50, 77, 78, 83, 84, 160, 161) and the or each average surface ( 28, 29, 33, 98, 103, 154, 155) are at least approximately planar.

11. Tool according to claim 10, characterized in that, respectively, said junction faces (41, 42, 47, 48, 49, 50, 77, 78, 83, 84, 160, 161) and said average surfaces (28 , 29, 108, 115, 144, 145, 146, 147) are at least approximately parallel to each other.

12. Tool according to any one of claims 9 to 11, characterized in that each section of second conduit (18, 25, 108, 115, 144, 145, 146, 147) has a rectilinear shape or a defined V shape by two rectilinear branches offset angularly.

13. Tool according to any one of claims 9 to 12, characterized in that when, in the case of an object (126) having the shape of a beam or a similar shape, elongated in a determined longitudinal direction (127), the forming face (133, 134) has an elongated shape in a determined longitudinal direction (127), the or each junction face (160, 161) and the or each average surface (154, 155 ) are at least approximately transverse, the or each first conduit (150, 153) is at least approximately transverse and constitutes a bypass (150, 153) and the or each second conduit (144, 145, 146, 147) is at least approximately longitudinal and constitutes a manifold (144, 145, 146, 147).

14. Tool according to any one of claims 9 to 12, characterized in that when, in the case of an object (1) having the shape of a pot or a similar shape, surrounding a determined longitudinal axis (4) , the forming face (16, 88) has a shape surrounding a determined longitudinal axis (4), the or each junction face (47, 48, 49, 77, 78, 83, 84) and the or each average surface ( 28, 33) are at least approximately transverse, the or each first conduit (27, 32, 96, 97, 102) is at least approximately transverse and constitutes a manifold (27, 32, 96, 97, 102) and the or each second conduit (25, 108, 115) is at least approximately longitudinal and constitutes a bypass (25, 108, 115).

15. Tool according to any one of claims 9 to 14, characterized in that each tool edge (35, 36, 37, 38, 39, 40, 69, 70, 71, 72, 73, 74, 156, 157) comes from machining in a block of thermally conductive raw material.

16. Tool according to claim 15, characterized in that said raw material is chosen from a group comprising cupro-Al ₂ 0 ₃ , cupro-cadmium, cupro-beryllium and stainless steels.

17. Tool according to any one of claims 9 to 16, characterized in that it constitutes a hot stamping tool, chosen from a group comprising the punches (2, 124) and the dies (3, 125).

18. Tool according to any one of claims 9 to 16, characterized in that it constitutes a part of an injection-molding mold.