EP0484789A1 - Method and device for producing holes in the wall of a hollow bodied workpiece - Google Patents

Method and device for producing holes in the wall of a hollow bodied workpiece Download PDF

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Publication number
EP0484789A1
EP0484789A1 EP91118373A EP91118373A EP0484789A1 EP 0484789 A1 EP0484789 A1 EP 0484789A1 EP 91118373 A EP91118373 A EP 91118373A EP 91118373 A EP91118373 A EP 91118373A EP 0484789 A1 EP0484789 A1 EP 0484789A1
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EP
European Patent Office
Prior art keywords
workpiece
formation
tool
wall
opening
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Granted
Application number
EP91118373A
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German (de)
French (fr)
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EP0484789B1 (en
Inventor
Gerhard Dipl.-Ing. Schiessl
Horst Dipl.-Ing. Lindner
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Audi AG
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Audi AG
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Publication of EP0484789A1 publication Critical patent/EP0484789A1/en
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    • 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
    • B21D26/021—Deforming sheet bodies
    • B21D26/023—Deforming sheet bodies including an additional treatment performed by fluid pressure, e.g. perforating
    • 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
    • B21D22/10—Stamping using yieldable or resilient pads
    • B21D22/105—Stamping using yieldable or resilient pads of tubular products
    • 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
    • B21D28/00—Shaping by press-cutting; Perforating
    • B21D28/007—Explosive cutting or perforating

Definitions

  • the invention relates to a method for producing an opening in the wall of a workpiece designed as a hollow body.
  • the object of the invention is to add a further one to these working methods.
  • the method according to the invention is used during the forming of the workpiece using the internal high-pressure method. This allows two processing steps to be carried out separately on a workpiece to be combined into a single work step.
  • the hydroforming process is preferably used for the production of differently shaped hollow parts and is a material-saving process that meets the requirements of a resource-saving manufacturing technology.
  • the operation of this forming process is such that a blank workpiece is placed in a mold, subjected to high internal pressure with the aid of a suitable hydraulic fluid, and is formed while simultaneously applying axial pressure to the tube wall. Axial pressure and internal pressure cause the workpiece blank to lie against the inner contour of the mold.
  • the material is brought into the plastic state, which is maintained during the entire forming process, taking material hardening and any tool forces into account.
  • a tool used to carry out the method according to the invention has both a sharp cutting edge and braking contours in the edge region of a formation, the latter having the task of specifically preventing the material in the region of the cutting edge from flowing again, as stated in claim 3, a defined predetermined breaking line is reliably formed in an advantageous manner.
  • a support surface which is preferably arranged centrally in the formation, as described in claim 4, limits the material stretch in the inner region of the workpiece wall to be cut out and at the same time increases the material stretch in the cantilever region.
  • the cut workpiece wall which may still be stuck in the formation, can be pressed out.
  • the hydroforming process essentially knows three basic processes, namely partial bulging in the closed tool, rotationally symmetrical widening in the closed tool and rotationally symmetrical widening in the open tool.
  • 1 shows the latter method in a schematic form.
  • a workpiece 1 designed as a tube is placed in an open (distance a o )
  • Tool 2 composed of upper and lower tool 2.1, 2.2 and moved during the forming process is inserted.
  • a cavity 3 of the workpiece 1 is filled with a liquid active medium via an inflow opening 4.
  • the forming takes place, during which the upper and lower tools 2.1, 2.2 move towards one another with an axial force F a, with the simultaneous effect of an internal pressure p i generated by the active medium, until the desired expansion shape is reached in the workpiece 1.
  • the internal pressure p i is to be selected as a function of the material and wall thickness of the workpiece 1 in particular.
  • the upper and lower tool 2.1, 2.2 still have a distance a1.
  • Reference number X identifies that tool area in which an opening is made in the manner according to the invention during the forming process. Further details can be found in FIG. 2.
  • FIG. 2 shows a section of the lower tool 2.2, which has on its inner wall surface 5 a shape 6 corresponding to the contour (for example rotationally symmetrical) of the desired workpiece opening.
  • a plunger 8 which can be acted upon by compressive force F s, projects through a bore 7 in the lower tool 2.2 into the formation 6, its end face 9 (with a rounded peripheral edge) serving as a support surface for the workpiece 1 during the manufacture of the opening.
  • the end face 9 limits the material stretch in this area and at the same time increases the material stretch in the cantilevered area of the formation 6.
  • a peripheral edge 10 of the formation 6 is sharp-edged (90 °) and serves as a cutting edge. Furthermore, near this edge 10, the inner wall surface 5 of the lower tool 2.2 is also equipped with circumferential serrated elevations 13, which act as braking contours and are intended to prevent the workpiece material from tiling in order to prevent the workpiece wall from tearing along the cut edge (edge 10) when it reaches one to favor certain internal pressure P i .
  • a ratio of d / D 1/3 should be maintained with regard to the ram cross-section d, the exact ratio depending in particular on the workpiece material and wall thickness and should be selected accordingly.
  • the distance T by which the end face 9 of the plunger 8 is set back relative to the inner wall surface 5 of the lower tool 2.2 is to be selected taking into account the diameter d, D and the material properties (maximum elongation at break ⁇ in%) of the workpiece 1.
  • the height and foot width of the serrated elevations 13 should correspond approximately to the wall thickness s of the workpiece 1.
  • a depth T 1 should be selected, for which at least the following should apply: T 1 ⁇ 1.5 T.
  • the plunger 8 also serves as an ejector, since it can happen that when the workpiece area to be cut breaks, it jams within the formation 6.
  • the ejection takes place before or during the opening of the upper and lower tool 2.1, 2.2 by a corresponding mechanical device which actuates the plunger 8.
  • the tool opening movement could be used to initiate the ram movement.
  • the ejection could also take place in a second step.
  • a support element could possibly be dispensed with.
  • T ⁇ D should then be observed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Insertion Pins And Rivets (AREA)

Abstract

The invention proposes a method for producing a hole in the wall of a work piece (1) designed as a hollow body, in which the work piece (1) is inserted into a form tool (2) which limits its radial expansion and is provided in the region of the envisaged hole with a recess (6) having an edge contour corresponding to the hole. The cavity (3) of the work piece (1) is then pressurised with a working medium up to an internal pressure pi which causes the edge (10) of the recess (6) to cut into the wall of the work piece. This advantageously takes place during another forming operation performed on the work piece (1) using the internal high-pressure forming method. <IMAGE>

Description

Die Erfindung bezieht sich auf ein Verfahren zum Herstellen eines Durchbruches in der Wandung eines als Hohlkörper ausgebildeten Werkstückes.The invention relates to a method for producing an opening in the wall of a workpiece designed as a hollow body.

Im Stand der Technik sind eine Reihe von Möglichkeiten bekannt (Bohren, Stanzen usw.), um beispielsweise rotationssymmetrische oder auch eine bestimmte Formkontur aufweisende Durchbrüche in die Wandung eines Werkstückes einzubringen.A number of possibilities are known in the prior art (drilling, punching, etc.) in order, for example, to introduce openings that are rotationally symmetrical or also have a specific shape contour into the wall of a workpiece.

Aufgabe der Erfindung ist es, diese Arbeitsverfahren um ein weiteres zu ergänzen.The object of the invention is to add a further one to these working methods.

Gelost wird diese Aufgabe erfindungsgemäß durch eine Verfahrensweise, wie sie im Kennzeichen des Patentanspruches 1 angegeben ist.This object is achieved according to the invention by a procedure as specified in the characterizing part of patent claim 1.

Aus der DE 39 25 821 A1 ist zwar ein mit einem Schaum gefüllter Energieabsorber bekannt geworden, der Öffnungen aufweist, durch die bereits zusammenengedrückter Schaum bei einem weiteren Kraftanstieg unter Energieabsorption ausgepreßt wird. Dabei wird die Öffnung erst beim Erreichen eines vorbestimmten Kraftniveaus dadurch geschaffen, daß ein durch eine Schwachstelle des Wandabschnittes umgrenzter Bereich abgetrennt wird. Anregungen, die die Erfindung hätten nahelegen können, sind aus diesem Stand der Technik allerdings nicht ableitbar.From DE 39 25 821 A1, an energy absorber filled with a foam is known, which has openings through which already compressed foam is pressed out with a further increase in force with energy absorption. The opening is only created when a predetermined force level is reached by separating an area delimited by a weak point in the wall section. However, suggestions that might have suggested the invention cannot be derived from this prior art.

In besonders vorteilhafter Weiterbildung wird das erfindungsgemäße Verfahren während eines Umformens des Werkstückes unter Anwendung des Innenhochdruckverfahrens angewendet. Dadurch lassen sich zwei an einem Werkstück an sich getrennt vorzunehmende Bearbeitungsschritte zu einem einzigen Arbeitsschritt vereinigen.In a particularly advantageous development, the method according to the invention is used during the forming of the workpiece using the internal high-pressure method. This allows two processing steps to be carried out separately on a workpiece to be combined into a single work step.

Das Innenhochdruckumformen (von vorzugsweise rohrförmigen Werkstücken) ist im Stand der Technik bekannt und in der einschlägigen Literatur beschrieben (DE-Z "Bänder Bleche Rohre" 6/1986, Seiten 117 bis 120; DE-Z "Bleche Rohre Profile" 35 (1988) 3, Seiten 175 bis 180; "Fortschrittsberichte" VDI Reihe 2 Nr. 142, VDI-Verlag; jeweils mit Querverweisen zu weiterführendem Schrifttum).Internal high-pressure forming (of preferably tubular workpieces) is known in the prior art and described in the relevant literature (DE-Z "Bänder Bleche Rohr" 6/1986, pages 117 to 120; DE-Z "Bleche Rohr Profile" 35 (1988) 3, pages 175 to 180; "Progress Reports" VDI Row 2 No. 142, VDI-Verlag; each with cross-references to further literature).

Das Innenhochdruckumformverfahren wird vorzugsweise zur Herstellung unterschiedlich geformter Hohlteile angewendet und ist ein materialsparendes Verfahren, das den Forderungen einer ressourcensparenden Fertigungstechnik entspricht. Die Arbeitsweise dieses Umformverfahrens ist dabei dergestalt, daß ein Werkstück-Rohling in eine Form gelegt, unter Zuhilfenahme eines geeigneten Hydraulikfluids mit hohem Innendruck beaufschlagt und unter gleichzeitiger Beaufschlagung mit axialem Druck auf die Rohrwandung umgeformt wird. Axialdruck und Innendruck bewirken, daß sich der Werkstück-Rohling an die Innenkontur der Form anlegt. Dabei wird der Werkstoff in den plastischen Zustand versetzt, der während des gesamten Umformvorganges unter Berücksichtigung von Werkstoffverfestigung und etwaiger Werkzeugkräfte aufrechterhalten bleibt.The hydroforming process is preferably used for the production of differently shaped hollow parts and is a material-saving process that meets the requirements of a resource-saving manufacturing technology. The operation of this forming process is such that a blank workpiece is placed in a mold, subjected to high internal pressure with the aid of a suitable hydraulic fluid, and is formed while simultaneously applying axial pressure to the tube wall. Axial pressure and internal pressure cause the workpiece blank to lie against the inner contour of the mold. The material is brought into the plastic state, which is maintained during the entire forming process, taking material hardening and any tool forces into account.

Dadurch, daß ein zur Durchführung des erfindungsgemäßen Verfahrens verwendetes Werkzeug im Randbereich einer Ausformung sowohl eine scharfe Schnittkante als auch Bremskonturen aufweist, wobei letztere die Aufgabe haben, den Werkstoff im Bereich der Schnittkante gezielt am Nachfließen zu hindern, wie dies in Patentanspruch 3 angegeben ist, wird in vorteilhafter Weise eine definierte Sollbruchlinie zuverlässig gebildet.Characterized in that a tool used to carry out the method according to the invention has both a sharp cutting edge and braking contours in the edge region of a formation, the latter having the task of specifically preventing the material in the region of the cutting edge from flowing again, as stated in claim 3, a defined predetermined breaking line is reliably formed in an advantageous manner.

Eine in der Ausformung vorzugsweise mittig angeordnete Abstützfläche, wie in Patentanspruch 4 beschrieben, begrenzt die Werkstoffstreckung im inneren Bereich der auszuschneidenden Werkstückwandung und erhöht gleichzeitig die Werkstoffstreckung im frei tragenden Bereich.A support surface which is preferably arranged centrally in the formation, as described in claim 4, limits the material stretch in the inner region of the workpiece wall to be cut out and at the same time increases the material stretch in the cantilever region.

Ist die Abstützfläche gleichzeitig Teil eines Auswerfers, wie dies in Anspruch 5 angegeben ist, so kann nach Herstellung des Durchbruches die in der Ausformung gebenenenfalls noch festsitzende ausgeschnittene Werkstückwandung herausgedrückt werden.If the support surface is at the same time part of an ejector, as specified in claim 5, after the opening has been made, the cut workpiece wall, which may still be stuck in the formation, can be pressed out.

Die Einhaltung der Randbedingungen, wie sie mit den Patentansprüchen 6 bis 10 angegeben sind, gewährleisten eine zuverlässige Herstellung des Durchbruches.Compliance with the boundary conditions, as specified in claims 6 to 10, ensure reliable manufacture of the breakthrough.

Die Erfindung ist nachstehend anhand eines Ausführungsbeispieles beschrieben, wobei die Herstellung des Durchbruches während eines Umformens eines Werkstückes unter Anwendung des Innenhochdruckverfahrens erfolgt. Die zugehörige Zeichnung zeigt in

Fig. 1
eine schematische Darstellung von Werkstück und Werkzeug in der Anordnung für ein rotationssymmetrisches Aufweitstauchen im geöffneten Werkzeug als eines der Grundverfahren des Innenhochdruckumformens und
Fig. 2
eine vergrößerte Darstellung des Bereiches X gemäß Fig. 1, in dem im Werkstück ein Durchbruch hergestellt wird.
The invention is described below on the basis of an exemplary embodiment, the opening being produced during the shaping of a workpiece using the internal high-pressure method. The associated drawing shows in
Fig. 1
is a schematic representation of the workpiece and tool in the arrangement for a rotationally symmetrical upsetting in the open tool as one of the basic methods of hydroforming and
Fig. 2
an enlarged view of the area X of FIG. 1, in which an opening is made in the workpiece.

Das Innenhochdruckumformverfahren kennt im wesentlichen drei Grundverfahren, nämlich das partielle Ausbauchen im geschlossenen Werkzeug, das rotationssymmetrische Aufweiten im geschlossenen Werkzeug und das rotationssymmetrische Aufweitstauchen im geöffneten Werkzeug. Fig. 1 zeigt in schematisierter Form das letztgenannte Verfahren. Dabei wird ein als Rohr ausgebildetes Werkstück 1 in ein geöffnetes (Abstand ao), aus Ober- und Unterwerkzeug 2.1, 2.2 sich zusammensetzendes und während des Umformvorganges mitbewegtes Werkzeug 2 eingelegt. Nach dem Einspannen und der Abdichtung mittels geeigneter Dichtringe (nicht dargestellt) wird ein Hohlraum 3 des Werkstückes 1 über eine Zuflußöffnung 4 mit einem flüssigen Wirkmedium gefüllt. Anschließend erfolgt die Umformung, wobei sich während des Umformvorganges Ober- und Unterwerkzeug 2.1, 2.2 solange mit einer Axialkraft Fa bei gleichzeitiger Wirkung eines vom Wirkmedium erzeugten Innendruckes pi aufeinander zubewegen, bis die gewünschte Aufweitform im Werkstück 1 erreicht ist. Der Innendruck pi ist in Abhängigkeit von insbesondere Werkstoff und Wandstärke des Werkstückes 1 zu wählen. Nach Abschluß des Umformvorganges weisen Ober- und Unterwerkzeug 2.1, 2.2 noch einen Abstand a₁ auf.The hydroforming process essentially knows three basic processes, namely partial bulging in the closed tool, rotationally symmetrical widening in the closed tool and rotationally symmetrical widening in the open tool. 1 shows the latter method in a schematic form. Here, a workpiece 1 designed as a tube is placed in an open (distance a o ), Tool 2 composed of upper and lower tool 2.1, 2.2 and moved during the forming process is inserted. After clamping and sealing by means of suitable sealing rings (not shown), a cavity 3 of the workpiece 1 is filled with a liquid active medium via an inflow opening 4. Subsequently, the forming takes place, during which the upper and lower tools 2.1, 2.2 move towards one another with an axial force F a, with the simultaneous effect of an internal pressure p i generated by the active medium, until the desired expansion shape is reached in the workpiece 1. The internal pressure p i is to be selected as a function of the material and wall thickness of the workpiece 1 in particular. After completion of the forming process, the upper and lower tool 2.1, 2.2 still have a distance a₁.

Ein detaillierteres Eingehen auf das Innenhochdruckumformverfahren dürfte entbehrlich sein. Es genügt an dieser Stelle ein Verweis auf die eingangs angegebene, insgesamt sehr umfangreiche Literatur hierzu.A more detailed discussion of the hydroforming process may not be necessary. At this point, it is sufficient to refer to the very extensive literature given at the beginning.

Mit der Bezugsziffer X ist derjenige Werkzeugbereich näher gekennzeichnet, in dem während des Umformvorganges auf erfindungsgemäße Weise ein Durchbruch hergestellt wird. Nähere Einzelheiten ergeben sich aus Fig. 2.Reference number X identifies that tool area in which an opening is made in the manner according to the invention during the forming process. Further details can be found in FIG. 2.

Fig. 2 zeigt ausschnittsweise das Unterwerkzeug 2.2, welches auf seiner inneren Wandfläche 5 eine der Kontur (beispielsweise rotationssymmetrisch) des gewünschten Werkstück-Durchbruches entsprechende Ausformung 6 aufweist. In deren mittlerem Bereich ragt durch eine Bohrung 7 im Unterwerkzeug 2.2 ein mittels Druckkraft Fs beaufschlagbarer Stößel 8 in die Ausformung 6 hinein, wobei dessen Stirnfläche 9 (mit abgerundeter Umfangskante) dem Werkstück 1 während der Herstellung des Durchbruches als Stützfläche dient.2 shows a section of the lower tool 2.2, which has on its inner wall surface 5 a shape 6 corresponding to the contour (for example rotationally symmetrical) of the desired workpiece opening. In its central area, a plunger 8, which can be acted upon by compressive force F s, projects through a bore 7 in the lower tool 2.2 into the formation 6, its end face 9 (with a rounded peripheral edge) serving as a support surface for the workpiece 1 during the manufacture of the opening.

Die Stirnfläche 9 begrenzt die Werkstoffstreckung in diesem Bereich und erhöht gleichzeitig die Werkstoffstreckung im frei tragenden Bereich der Ausformung 6.The end face 9 limits the material stretch in this area and at the same time increases the material stretch in the cantilevered area of the formation 6.

Eine umlaufende Kante 10 der Ausformung 6 ist scharfkantig ausgeführt (90°) und dient insoweit als Schnittkante. Desweiteren ist nahe dieser Kante 10 die innere Wandfläche 5 des Unterwerkzeuges 2.2 mit ebenfalls umlaufenden zackenförmigen Erhebungen 13 ausgestattet, die als Bremskonturen wirken und ein Nachfliesen des Werkstück-Werkstoffes verhindern sollen, um das Einreißen der Werkstückwandung entlang der Schnittkante (Kante 10) bei Erreichen eines bestimmten Innendruckes Pi zu begünstigen.A peripheral edge 10 of the formation 6 is sharp-edged (90 °) and serves as a cutting edge. Furthermore, near this edge 10, the inner wall surface 5 of the lower tool 2.2 is also equipped with circumferential serrated elevations 13, which act as braking contours and are intended to prevent the workpiece material from tiling in order to prevent the workpiece wall from tearing along the cut edge (edge 10) when it reaches one to favor certain internal pressure P i .

Dabei kommt es bei zunehmendem Innendruck pi zu einem verstärktem Einschneiden des Werkstoffes. Außerdem ist in der Schneidkanteneinflußzone ein gleichmäßiger Festigkeitszustand gegeben, so daß an der Kante 10 die Beanspruchung steigt. Ist der Werkstoff etwa in der Größenordnung 1/3 s (s = Werkstück-Wandstärke) eingeschnitten, so kommt es zum Bruch.As the internal pressure p i increases, there is an increased incision in the material. In addition, there is a uniform state of strength in the cutting edge influence zone, so that the stress increases at the edge 10. If the material is cut in the order of 1/3 s (s = workpiece wall thickness), it breaks.

Ist die Ausformung 6 kreisförmig (Durchmesser D), so sollte bezüglich des Stößelquerschnittes d etwa ein Verhältnis von d/D = 1/3 eingehalten werden, wobei das genaue Verhältnis insbesondere von Werkstück-Werkstoff und -Wandstärke abhängig und entsprechend zu wählen ist.If the shape 6 is circular (diameter D), a ratio of d / D = 1/3 should be maintained with regard to the ram cross-section d, the exact ratio depending in particular on the workpiece material and wall thickness and should be selected accordingly.

Der Abstand T, um den die Stirnfläche 9 des Stößels 8 gegenüber der inneren Wandfläche 5 des Unterwerkzeuges 2.2 zurückversetzt ist, ist unter Berücksichtigung der Durchmesser d, D und der Werkstoffeigenschaften (maximale Bruchdehnung δ in %) des Werkstückes 1 zu wählen.The distance T by which the end face 9 of the plunger 8 is set back relative to the inner wall surface 5 of the lower tool 2.2 is to be selected taking into account the diameter d, D and the material properties (maximum elongation at break δ in%) of the workpiece 1.

Höhe und Fußbreite der zackenförmigen Erhebungen 13 sollten in etwa der Wandstärke s des Werkstückes 1 entsprechen. Im Übergangsbereich zwischen Mantelfläche 14 und Stirnfläche 9 des Stößels 8 sollte eine Rundung vorhanden sein, deren Radius R mindestens der Werkstückwandstärke s entsprechen sollte. Für die Ausformung 6 ist eine Tiefe T₁ zu wählen, für die zumindest gelten sollte: T₁ ≧ 1,5 T.The height and foot width of the serrated elevations 13 should correspond approximately to the wall thickness s of the workpiece 1. In the transition area between the outer surface 14 and the end face 9 of the plunger 8 there should be a rounding, the radius R of which should at least correspond to the workpiece wall thickness s. For the formation 6, a depth T 1 should be selected, for which at least the following should apply: T 1 ≧ 1.5 T.

Der Stößel 8 dient gleichzeitig als Auswerfer, da es durchaus passieren kann, daß beim Bruch des auszuschneidenden Werkstückbereiches sich dieser innerhalb der Ausformung 6 verklemmt. Das Auswerfen erfolgt vor oder während des Öffnens von Ober- und Unterwerkzeug 2.1, 2.2 durch eine entsprechende mechanische Einrichtung, die den Stößel 8 betätigt. Dabei könnte die Werkzeug-Öffnungsbewegung genutzt werden, um die Stößelbewegung einzuleiten. Selbstverständlich könnte das Auswerfen auch in einem zweiten Arbeitsschritt erfolgen.The plunger 8 also serves as an ejector, since it can happen that when the workpiece area to be cut breaks, it jams within the formation 6. The ejection takes place before or during the opening of the upper and lower tool 2.1, 2.2 by a corresponding mechanical device which actuates the plunger 8. The tool opening movement could be used to initiate the ram movement. Of course, the ejection could also take place in a second step.

Soweit die in das Werkstück 1 einzubringende Durchbrechung ein gewisses Maß (z. B. ø < 8 mm) unterschreitet, könnte gegebenenfalls auf ein Stützelement verzichtet werden. Für eine kreisförmige Ausformung sollte dann T ≧ D eingehalten werden.If the opening to be made in the workpiece 1 falls below a certain dimension (for example ø <8 mm), a support element could possibly be dispensed with. For a circular shape, T ≧ D should then be observed.

Claims (10)

Verfahren zur Herstellung eines Durchbruches in der Wandung eines als Hohlkörper ausgebildeten Werkstückes, dadurch gekennzeichent, - daß das Werkstück (1) in ein eine durch Einwirken von Verformungskräften hervorrufbare Aufweitung begrenzendes Formwerkzeug (2) eingesetzt wird, welches im Bereich des vorgesehenen Durchbruches mit einer Ausformung (6) mit einer dem Durchbruch entsprechenden Randkontur versehen ist, - daß der Hohlraum (3) des Werkstückes (1) mit einem Wirkmedium bis zu einem das Einschneiden der Werkstückwandung entlang einer Kante (10) der Ausformung (6) bewirkenden Inndendruck (pi) beaufschlagt wird. Method for producing an opening in the wall of a workpiece designed as a hollow body, characterized in that - The workpiece (1) is inserted into a shaping tool (2) which delimits an expansion which can be caused by the action of deformation forces and which is provided in the area of the intended opening with a formation (6) with an edge contour corresponding to the opening, - That the cavity (3) of the workpiece (1) with an active medium up to a cutting the workpiece wall along an edge (10) of the formation (6) causing internal pressure (p i ) is applied. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Herstellung des Durchbruches während eines Umformens des Werkstückes (1) unter Anwendung des Innenhochdruckumformverfahrens erfolgt.Method according to Claim 1, characterized in that the opening is produced during the forming of the workpiece (1) using the internal high-pressure forming method. Werkzeug zur Durchführung des Verfahrens nach Anspruch 1, gekennzeichnet durch das Werkstück (1) aufnehmende Ober- und Unterwerkzeuge (2.1, 2.2) mit einer Wirkmedium-Zuflußöffnung (4) und einer im Bereich des vorgesehenen Durchbruches angeordneten Ausformung (6), wobei der Übergang von einer inneren Werkzeug-Wandfläche (5) zur Ausformung (6) scharfkantig ist (Kante 10) und nahe dieser die Wandfläche (5) mit nach innen ragenden, entlang der Kante (10) verlaufenden zackenförmigen Erhebungen (13) ausgestattet ist.Tool for performing the method according to claim 1, characterized by the workpiece (1) receiving upper and lower tools (2.1, 2.2) with an active medium inflow opening (4) and a formation (6) arranged in the area of the intended opening, the transition from an inner tool wall surface (5) to the formation (6) is sharp-edged (edge 10) and near this the wall surface (5) is provided with inwardly projecting, jagged elevations (13) running along the edge (10). Werkzeug nach Anspruch 3, dadurch gekennzeichnet, daß im mittleren Bereich der Ausformung (6) durch eine Bohrung (7) des Unterwerkzeuges (2.2) ein Stößel (8) in die Ausformung (6) hineinragt, dessen Stirnfläche (9) das sich in diesem Bereich verformende Werkstück (1) abstützt.Tool according to claim 3, characterized in that in the central region of the formation (6) through a bore (7) of the lower tool (2.2) a plunger (8) protrudes into the formation (6), the end face (9) of which supports the workpiece (1) deforming in this area. Werkzeug nach Anspruch 4, dadurch gekennzeichnet, daß der Stößel (8) als Auswerfer dient und von einer Druckkraft Fs beaufschlagbar ist.Tool according to claim 4, characterized in that the plunger (8) serves as an ejector and can be acted upon by a pressure force F s . Werkzeug nach Anspruch 4, dadurch gekennzeichnet, daß bei kreisförmigem Querschnitt von Stößel (8) und Ausformung (6) das Verhältnis d : D ≈ 1:3 ist, wobei d der Stößeldurchmesser und D der Ausformungsdurchmesser ist.Tool according to claim 4, characterized in that in the case of a circular cross section of the plunger (8) and the molding (6), the ratio is d: D ≈ 1: 3, where d is the plunger diameter and D is the molding diameter. Werkzeug nach Anspruch 4, dadurch gekennzeichnet, daß der Übergang der Mantelfläche (14) des Stößels (8) zu dessen Stirnfläche (9) eine Rundung aufweist, für deren Radius R die Beziehung gilt:

R ≧ 1 x s
Figure imgb0001

wobei s die Werkstück-Wandstärke ist.Tool according to claim 4, characterized in that the transition from the lateral surface (14) of the plunger (8) to the end face (9) thereof has a rounding, for the radius R of which the relationship applies:

R ≧ 1 xs
Figure imgb0001

where s is the workpiece wall thickness. Werkzeug nach Anspruch 4, dadurch gekennzeichnet, daß für die Tiefe T₁ der Ausformung (6) die Beziehung gilt:

T₁ ≧ 1,5 x T
Figure imgb0002

wobei T das Maß darstellt, um welches die Stößel-Stirnfläche (9) gegenüber der inneren Wandfläche (5) des Werkstückes (1) zurückversetzt ist.Tool according to Claim 4, characterized in that the relationship applies to the depth T₁ of the formation (6):

T₁ ≧ 1.5 x T
Figure imgb0002

where T represents the amount by which the ram end face (9) is set back from the inner wall surface (5) of the workpiece (1). Werkzeug nach Anspruch 3, dadurch gekennzeichnet, daß bei einer kreisförmigen Ausformung (6) deren Tiefe T₁ stets größer ist, als ihr Durchmesser D.Tool according to Claim 3, characterized in that, in the case of a circular shape (6), its depth T₁ is always greater than its diameter D. Werkzeug nach Anspruch 3, dadurch gekennzeichnet, daß die zackenförmigen Erhebungen (13) jeweils eine Höhe und eine Fußbreite aufweisen, die höchstens der Werkstück-Wandstärke s entsprechen.Tool according to claim 3, characterized in that the serrated elevations (13) each have a height and a foot width which at most correspond to the workpiece wall thickness s.
EP91118373A 1990-11-09 1991-10-29 Method and device for producing holes in the wall of a hollow bodied workpiece Expired - Lifetime EP0484789B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4035625A DE4035625A1 (en) 1990-11-09 1990-11-09 METHOD FOR PRODUCING A BREAKTHROUGH IN THE WALL OF A WORKPIECE DESIGNED AS A HOLLOW BODY, AND TOOL FOR CARRYING OUT THE METHOD
DE4035625 1990-11-09

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EP0484789B1 EP0484789B1 (en) 1995-04-12

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FR2708220A1 (en) * 1993-07-02 1995-02-03 Schafer Maschinenbau Gmbh Co W A method of cutting a portion of a wall of a hollow body manufactured according to the forming method using a high internal pressure.
US5398533A (en) * 1994-05-26 1995-03-21 General Motors Corporation Apparatus for piercing hydroformed part
DE19506067C1 (en) * 1995-02-22 1996-06-20 Krupp Ag Hoesch Krupp Aperture cutter for pressure moulded items
US5666840A (en) * 1996-06-13 1997-09-16 General Motors Corporation Method for piercing two aligned holes in a hydroformed tube
WO1997039850A1 (en) * 1996-04-23 1997-10-30 Clf International Limited Techniques and apparatus for cutting a workpiece
EP0845312A1 (en) * 1996-12-02 1998-06-03 Forschungsgesellschaft Umformtechnik m.b.H. Flexibly applicable die for high pressure forming
US5996455A (en) * 1996-11-20 1999-12-07 Daimlerchrysler Ag Method and device for making holes at the circumference of a hollow shape
DE19724037C2 (en) * 1997-06-06 2000-08-31 Audi Ag Process for cutting a hollow body
US6430981B1 (en) * 2000-06-20 2002-08-13 Daimlerchrysler Ag Method and device for producing leadthroughs on hollow profiles
US6484551B1 (en) * 1996-11-20 2002-11-26 Daimlerchrysler Ag Process for manufacturing holes on the circumference of hollow sections
EP1430966A3 (en) * 2002-12-21 2005-03-09 Bayerische Motoren Werke Aktiengesellschaft Method for producing a metal workpiece and forming press for carrying out the method

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DE19532860A1 (en) * 1995-09-06 1997-03-13 Behr Gmbh & Co Method and tool for producing a one-piece manifold
DE19747607A1 (en) * 1997-10-28 1999-05-06 Forschungsges Umformtechnik Punching method for hollow workpieces
DE19805275B4 (en) * 1998-02-11 2004-07-15 Dr. Meleghy Hydroforming Gmbh & Co. Kg Method and device for making an opening in a wall
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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2708220A1 (en) * 1993-07-02 1995-02-03 Schafer Maschinenbau Gmbh Co W A method of cutting a portion of a wall of a hollow body manufactured according to the forming method using a high internal pressure.
US5398533A (en) * 1994-05-26 1995-03-21 General Motors Corporation Apparatus for piercing hydroformed part
DE19506067C1 (en) * 1995-02-22 1996-06-20 Krupp Ag Hoesch Krupp Aperture cutter for pressure moulded items
WO1997039850A1 (en) * 1996-04-23 1997-10-30 Clf International Limited Techniques and apparatus for cutting a workpiece
US5666840A (en) * 1996-06-13 1997-09-16 General Motors Corporation Method for piercing two aligned holes in a hydroformed tube
US5996455A (en) * 1996-11-20 1999-12-07 Daimlerchrysler Ag Method and device for making holes at the circumference of a hollow shape
US6484551B1 (en) * 1996-11-20 2002-11-26 Daimlerchrysler Ag Process for manufacturing holes on the circumference of hollow sections
EP0845312A1 (en) * 1996-12-02 1998-06-03 Forschungsgesellschaft Umformtechnik m.b.H. Flexibly applicable die for high pressure forming
DE19724037C2 (en) * 1997-06-06 2000-08-31 Audi Ag Process for cutting a hollow body
US6430981B1 (en) * 2000-06-20 2002-08-13 Daimlerchrysler Ag Method and device for producing leadthroughs on hollow profiles
EP1430966A3 (en) * 2002-12-21 2005-03-09 Bayerische Motoren Werke Aktiengesellschaft Method for producing a metal workpiece and forming press for carrying out the method

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DE59105166D1 (en) 1995-05-18
EP0484789B1 (en) 1995-04-12
ES2071886T3 (en) 1995-07-01

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