EP0438774B1 - Verfahren zum Ziehen von Blechen und hydraulische Presse zum Durchführen des Verfahrens - Google Patents

Verfahren zum Ziehen von Blechen und hydraulische Presse zum Durchführen des Verfahrens Download PDF

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Publication number
EP0438774B1
EP0438774B1 EP90125420A EP90125420A EP0438774B1 EP 0438774 B1 EP0438774 B1 EP 0438774B1 EP 90125420 A EP90125420 A EP 90125420A EP 90125420 A EP90125420 A EP 90125420A EP 0438774 B1 EP0438774 B1 EP 0438774B1
Authority
EP
European Patent Office
Prior art keywords
blank
holder
metal sheet
metal
hydraulic press
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP90125420A
Other languages
English (en)
French (fr)
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EP0438774A1 (de
Inventor
Mario Da Re'
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fiat Auto SpA
Original Assignee
Fiat Auto SpA
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Filing date
Publication date
Application filed by Fiat Auto SpA filed Critical Fiat Auto SpA
Publication of EP0438774A1 publication Critical patent/EP0438774A1/de
Application granted granted Critical
Publication of EP0438774B1 publication Critical patent/EP0438774B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
    • B21D24/10—Devices controlling or operating blank holders independently, or in conjunction with dies
    • 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
    • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
    • B21D24/10—Devices controlling or operating blank holders independently, or in conjunction with dies
    • B21D24/14—Devices controlling or operating blank holders independently, or in conjunction with dies pneumatically or hydraulically

Definitions

  • the present invention relates to a method of pressing sheet metal, including the steps of providing a press having a punch, a die, and a blank-holder for restraining a metal sheet at an edge region of the die by clamping it between the blank-holder and the edge region.
  • the present invention also relates to a hydraulic press for pressing sheet metal, of the type including at least one blank-holder operated by actuators through an hydraulic operating circuit.
  • the optimum clamping pressure for the blank-holder is determined empirically and, during normal production, is kept constant throughout the pressing period. With this constant-pressure method, difficulties are encountered with complex dies and deep drawing. Moreover, the characteristics of the metal sheets and their pre-treatment (for example, with lubricants) represent variables which may mean that the clamping pressure, which is determined empirically beforehand, is not at an optimum.
  • DE-A-3744177 discloses a method of pressing sheet metal in which the force having effect on the blank-holder is electronically controlled according to a predetermined law.
  • the control system used in such known process needs a central process unit and a sensor of the punch's travel in order to make the pressure acting on the blank-holder dependent from the position of the punch.
  • the object of the present invention is to provide a pressing method of the type specified at the beginning of the description which does not have the aforementioned disadvantages and which is simple and cheap to put into practice.
  • this object is achieved by virtue of the fact that the blank-holder is clamped onto the metal sheet with a force which can be alternated cyclically and repeatedly between minimum and maximum values during the deforming of a metal sheet.
  • the repeated alternation of the pressure of the blank-holder between a maximum value and a minimum value at a suitable frequency enables the metal sheet to adapt itself to the requirements of deformation during the pressing regardless of the nature of the metal sheet and its surface treatment.
  • the step of adjusting the clamping pressure is eliminated and the drawing depth can be increased.
  • the method according to the invention can be carried out on a hydraulic press for pressing sheet metal, of the type including at least one blank-holder operated by actuators through an hydraulic operating circuit, in which the hydraulic circuit includes valve means for alternately depressurising/pressurising the actuators of the blank-holder to cause the clamping pressure of the blank-holder to vary repeatedly according to a predetermined law.
  • a hydraulic press indicated 10, includes a die 12, a punch 14 and a blank-holder 16.
  • a flat metal sheet L is interposed between the blank-holder and the die 12 for drawing.
  • the press 10 has a special hydraulic circuit 18 for operating actuators 20 associated with the blank-holder 16.
  • the hydraulic circuit 18 includes a valve unit 22 for cutting off the flow supplied by a pump p for very short periods at a frequency which is variable in dependence on the type of die but is preferably between 20 and 30 Hz.
  • the valve unit 22 is not discussed in detail herein since it is of substantially the same type as is used, for example, in anti-lock braking systems for automatically pressurising/depressurising the hydraulic circuit associated with the brakes.
  • the pressure for operating the blank-holder 16 is applied and released within a range defined by a maximum value and a minimum value, or within a suitable interval between these values.
  • the valve means 22 may be associated with an electronic control system for modulating the pressurisation/depressurisation frequency in dependence on the various geometries of the dies, acting separately on the actuators 20 of the blank-holder 16. In this case, the optimum pressure interval and the individual control of the actuators 20 will be determined in dependence on the various geometries of the dies.
  • Figure 2 shows a second embodiment of the invention which uses a die 25 with two superposed cavities 25a acted on by two opposed punches 14.
  • the operation of the two blank-holders 16 is essentially identical to that described for Figures 1 and 3.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Laminated Bodies (AREA)

Claims (3)

  1. Verfahren zum Umformen von Blech, umfassend die Schritte des Bereitstellens einer Presse (10) mit einem Stempel (14), einer Form (12) und eines Formling-Halters (16) zum Festhalten eines Blechs (L) an einem Randbereich der Form (12) durch Klemmen desselben zwischen den Formling-Halter (16) und den Randbereich,
    dadurch gekennzeichnet, daß
    der Formling-Halter (16) auf das Blech (L) mit einer Kraft geklemmt wird, welche während der Verformung eines Blechs (L) mit einer geeigneten Frequenz, vorzugsweise 20 bis 30 Hz, zyklisch und in sich wiederholender Weise zwischen Minimal- und Maximalwerten alterniert wird, um zu ermöglichen, daß sich das Blech (L) den Verformungserfordernissen anpaßt.
  2. Hydraulische Presse zum Umformen von Blech, welche dem Typ angehört, der wenigstens einen von den Aktuatoren (20) durch einen hydraulischen Betätigungskreis (18) betätigten Formling-Halter (16) umfaßt,
    dadurch gekennzeichnet, daß
    der hydraulische Kreis (18) Ventilmittel (22) zum alternativen Druckverringern/Druckerhöhen der Aktuatoren (20) des Formling-Halters (16) umfaßt, um den Klemmdruck des Formling-Halters (16) während der Verformung eines Blechs (L) mit einer geeigneten Frequenz, vorzugsweise 20 bis 30 Hz, zwischen Minimal- und Maximalwerten zyklisch und in sich wiederholender Weise zu alternieren, um zu ermöglichen, daß sich das Blech (L) den Verformungserfordernissen anpaßt.
  3. Hydraulische Presse nach Anspruch 2,
    dadurch gekennzeichnet, daß
    die Ventilmittel (22) dazu ausgebildet sind, den Betätigungsdruck jedes Aktuators (20) des Formling-Halters (16) gemäß einer Gesetzmäßigkeit zu alternieren, welche sich von der jedes anderen Aktuators (20) unterscheidet.
EP90125420A 1990-01-24 1990-12-24 Verfahren zum Ziehen von Blechen und hydraulische Presse zum Durchführen des Verfahrens Expired - Lifetime EP0438774B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT67049A IT1239856B (it) 1990-01-24 1990-01-24 Procedimento per lo stampaggio di lamiere e pressa idraulica per la realizzazione di tale procedimento.
IT6704990 1990-01-24

Publications (2)

Publication Number Publication Date
EP0438774A1 EP0438774A1 (de) 1991-07-31
EP0438774B1 true EP0438774B1 (de) 1994-04-13

Family

ID=11299181

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90125420A Expired - Lifetime EP0438774B1 (de) 1990-01-24 1990-12-24 Verfahren zum Ziehen von Blechen und hydraulische Presse zum Durchführen des Verfahrens

Country Status (4)

Country Link
EP (1) EP0438774B1 (de)
DE (1) DE69008148T2 (de)
ES (1) ES2050928T3 (de)
IT (1) IT1239856B (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0536952A1 (de) * 1991-10-02 1993-04-14 Toyo Seikan Kaisha Limited Verfahren zum Tiefziehen von Metallblech mit einer filmartigen organischen Beschichtung
EP0703018A1 (de) 1994-09-26 1996-03-27 Maschinenfabrik Müller-Weingarten Ag Mechanische oder hydraulische Presse
DE10344941A1 (de) * 2003-09-27 2005-04-28 Karmann Gmbh W Steuervorrichtung für eine Presse zum Tiefziehen von Werkstücken
DE102006019502B3 (de) * 2006-04-26 2007-10-18 Moog Gmbh Verfahren zum Umformen von Blechen mit stochastischem Pulsationsmuster

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1260615B (it) * 1993-03-02 1996-04-22 Fiat Auto Spa Procedimento e pressa idraulica per lo stampaggio di lamiere
SE9301278L (sv) * 1993-04-19 1994-05-24 Ap & T Tranemo Ab Hydraulpress för djupdragning
EP1593443A1 (de) * 2004-05-07 2005-11-09 Walter, Neff GmbH Umformpresse
DE102008062850B4 (de) 2008-12-23 2013-11-21 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Verfahren zur Herstellung eines Tiefziehteils sowie ein Verfahren zur Steuerung einer Tiefziehvorrichtung und eine Tiefziehvorrichtung

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3640507C3 (de) * 1986-11-27 1998-01-29 Mueller Weingarten Maschf Einrichtung zur Steuerung bzw. Regelung der Blechhalterkraft während des Ziehvorganges
DE3735582C1 (de) * 1987-10-21 1988-04-28 Daimler Benz Ag Doppeltwirkende Presse zum Ziehen von Blechteilen
DE3735581C1 (de) * 1987-10-21 1988-05-11 Daimler Benz Ag Presse zum Ziehen von Blechteilen
DE3744177A1 (de) * 1987-12-24 1989-07-06 Audi Ag Verfahren zum tiefziehen von platinen, insbesondere von tiefziehblechen fuer karosserieelemente von kraftfahrzeugen

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0536952A1 (de) * 1991-10-02 1993-04-14 Toyo Seikan Kaisha Limited Verfahren zum Tiefziehen von Metallblech mit einer filmartigen organischen Beschichtung
US5433099A (en) * 1991-10-02 1995-07-18 Toyo Seikan Kaisha, Ltd. Method of draw-forming a metal sheet having an organic film
EP0703018A1 (de) 1994-09-26 1996-03-27 Maschinenfabrik Müller-Weingarten Ag Mechanische oder hydraulische Presse
DE10344941A1 (de) * 2003-09-27 2005-04-28 Karmann Gmbh W Steuervorrichtung für eine Presse zum Tiefziehen von Werkstücken
DE10344941B4 (de) * 2003-09-27 2006-09-28 Wilhelm Karmann Gmbh Vorrichtung zum Steuern einer Werkstückhaltekraft einer Presse zum Tiefziehen von Werkstücken
DE102006019502B3 (de) * 2006-04-26 2007-10-18 Moog Gmbh Verfahren zum Umformen von Blechen mit stochastischem Pulsationsmuster

Also Published As

Publication number Publication date
ES2050928T3 (es) 1994-06-01
DE69008148D1 (de) 1994-05-19
IT1239856B (it) 1993-11-15
DE69008148T2 (de) 1994-07-21
EP0438774A1 (de) 1991-07-31
IT9067049A1 (it) 1991-07-24
IT9067049A0 (it) 1990-01-24

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