EP0713735B1 - Clamping device between the upper and lower tool of a press - Google Patents

Clamping device between the upper and lower tool of a press Download PDF

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Publication number
EP0713735B1
EP0713735B1 EP95117213A EP95117213A EP0713735B1 EP 0713735 B1 EP0713735 B1 EP 0713735B1 EP 95117213 A EP95117213 A EP 95117213A EP 95117213 A EP95117213 A EP 95117213A EP 0713735 B1 EP0713735 B1 EP 0713735B1
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EP
European Patent Office
Prior art keywords
stroke
short
pressure
clamping arrangement
cylinder
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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.)
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EP95117213A
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German (de)
French (fr)
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EP0713735A1 (en
Inventor
Wieland Dr. Petter
Gregor Geist
Andreas Schlag
Markus Dr. Müller
Wolf-Eckehart Gödel
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Umformtechnik Erfurt GmbH
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Umformtechnik Erfurt GmbH
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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
    • 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 invention relates to a Clamping device according to the preamble of claim 1.
  • a hydraulic cushion assembly for a press which is intended to apply a cushion force that is uniform for a workpiece across all pressure bolts.
  • a plurality of short-stroke cylinders that are fluidly connected to one another and whose short-stroke pistons are operatively connected to the pressure bolts are arranged on a pressure-pin plate that can be moved by the die cushion.
  • the short-stroke cylinders are connected to a hydraulic supply device to supply them with pressure medium.
  • the hydraulic supply device contains elements for changing an initial pressure in the short-stroke cylinders. This pressure change takes place before the start of the pressing operation.
  • the problem underlying the invention is a compensation device to create that with simple technical Averaging ensures that all thrust bolts have the same force transfer the force of the short-stroke cylinder with each other before full adhesion is reached almost excluded between the functional elements and the contact pattern of all pressure bolts achieved in this way is reproducible is.
  • the prerequisite for this is that all pressure bolts under Experience the same compression. This in turn does on the condition that geometric deviations of the in Functional elements lying in the power flow can be compensated.
  • Push pin points of the push pin plate with short stroke cylinders can be occupied, but expediently only those necessary according to an empirical determination Push pin points within the framework of the standardized grid Short stroke cylinders are occupied. While adjusting the Number and position of the pressure bolts for each tool manually takes place in the known form when changing tools the not necessary but on the push pin plate Existing short stroke cylinders are depressurized and so from communicating system can be disconnected. Likewise can determine the pressure pin points required for the specific tool to be covered with pressure bolts and the ones that still exist Short stroke piston of the unnecessary pressure pin points "blind" continue to operate. Alternatively, you can all existing short stroke cylinders are operated and only the pressure pin points required for the specific tool Pressure bolts are occupied.
  • the equipment can also do so be designed so that the individual when changing tools Short stroke cylinders in their assignment to the pressure bolts can be moved or removed and retrofitted. When change the number of pressure bolts and / or geometry deviations of the functional elements is a change in volume of the Compensation room expedient in the compensation cylinder.
  • the short stroke cylinders can also be used with different Active areas are formed.
  • the press ram 1 with the upper tool of a mechanical or hydraulic press comes into operative connection with the lower tool arranged on the sliding table 2 in a known manner according to FIG. 1.
  • the upper and lower tools are not shown. Due to geometrical deviations of the functional elements lying in the power flow during the drawing process, which in total are expressed in terms of the length difference 8, each of the pressure bolts 7 with y 1 to y n , there is no simultaneous contact of all relevant components.
  • the pressure pin plate 3 guided in the press table 4 is operatively connected in a known manner to a die cushion arranged on the cross member 19.
  • the die cushion piston 18 is acted upon by the die cushion force 23.
  • the short-stroke cylinders 5 are arranged on the pressure pin plate 3 and are flow-connected to one another via connecting lines 20.
  • a pressure pin 7 can be assigned to each short-stroke piston 6.
  • the flow-connected short-stroke cylinders 5 are connected via a connecting line 14 to a compensation chamber 22 of a compensation cylinder 10 which is preferably rigidly arranged on the pressure pin plate 3.
  • This connecting line 14 is simultaneously connected via a directional valve 17, to which a pressure relief valve 24 is connected in parallel, to a pressure medium container 16 integrated in the compensation cylinder 10.
  • the pressure medium container 16 is operatively connected to a pressure regulating device 15 via a directional valve 21.
  • An adjustable stroke limiter 13 is arranged on the piston rod rigidly connected to the compensation piston 11. Before the introduction of force from the press ram 1 via the upper tool into the pressure bolts 7, the short-stroke pistons 6 are in their upper, mechanically limited starting position, into which they are brought and held by spring force.
  • the spring can be mechanical or generated by pneumatic pressure.
  • the compensation piston 11 is in its mechanical, lower end position. With the first contact between the driving system of press ram 1 with the upper tool and the stationary drawing cushion with the pressure pin plate 3, the drawing cushion piston 18, the short-stroke cylinders 5 and the pressure pin 7, the relevant short-stroke piston 6 is displaced by the displacement stroke 9.
  • This displacement stroke 9 is in each case Short stroke cylinder 5 different and designated x 1 to x n .
  • all pressure bolts 7 follow until the start of drawing and displace pressure medium via the connecting lines 20 and 14 into the compensation chamber 22 of the compensation cylinder 10.
  • the pressure piston is displaced from the short-stroke cylinders 5 and the compensation piston 11 is displaced by the compensation stroke 12
  • This compensation stroke 12 and thus the sum of the pressure medium displaced from the short stroke cylinders 5 is determined by the adjustable stroke limiter 13.
  • Due to the mechanically limited volume absorption in the compensation cylinder 10, the displacement stroke 9 of the short-stroke piston 6 is interrupted in the drawing direction.
  • the pressure bolts are thus driven further against the acting die cushion force 23, which is supported on the press table 4 via the crossmember 19.
  • the qualitative position of the functional elements at the start of drawing is shown in FIG. 2.
  • the directional control valve 17 is located in the blocking position from the connecting line 14 in the direction of the pressure medium container 16.
  • the pressure relief valve 24 is arranged parallel to the directional control valve 17 to protect the hydraulic system against overload.
  • the directional valve 17 can also be designed as a continuous valve.
  • the pressure medium is returned from the compensation space 22 into the short-stroke cylinders 5, whereby the short-stroke pistons 6 reach their starting position.
  • the pressure medium is acted upon by pneumatic pressure via the pressure control device 15 and the directional control valve 21.
  • the pressure in the pressure medium container 16 causes a corresponding force through the differential area, which causes the pressure medium to flow back from the compensation chamber 22 guaranteed.
  • the pressure pin plate 3 a standardized number of pressure pin points 25.
  • the Need these individual pressure pin points 25 per tool is known to be very different.
  • the assembly of all or only for one Tool required pressure pin points 25 with short-stroke cylinders 5 is suggested, according to an empirical determined necessary pin assignment for Tools in a certain period of time short-stroke cylinder 5 too operate and only according to the respective tool required pressure pin points 25 with pressure pin 7 equip or those that are not required Push pin points 25 by "depressurizing" the not to put the required short stroke cylinder 5 out of operation.
  • the directional control valves 26 and 27 are between the short-stroke cylinders 5 and the pressure medium container 16 arranged and connected in series. They allow that for a Tool not required short stroke cylinder 5 relieved of pressure and thus be put out of operation. If necessary, the Number of short-stroke cylinders 5 adapted for each tool become. For this purpose, the short-stroke cylinders 5 are spatially Arrangement can be changed or removed and retrofitted. At Change in the number of pressure bolts 7 and / or Part geometry or the length difference 8 is one Volume change of the compensation space 22 by means of Stroke limitation 13 expedient.

Description

Die Erfindung betrifft eine Klemmeinrichtung nach dem Oberbegriff des Patentanspruches 1.The invention relates to a Clamping device according to the preamble of claim 1.

Nach der EP 0 531 140 A1 ist ein hydraulisches Kissenaggregat für eine Presse bekannt, das eine für ein Werkstück einheitliche Kissenkraft über alle Druckbolzen aufbringen soll. Dazu sind auf einer vom Ziehkissen bewegbaren Druckbolzenplatte eine Mehrzahl von untereinander fließverbundenen Kurzhubzylindern angeordnet, deren Kurzhubkolben mit den Druckbolzen wirkverbunden sind. Die Kurzhubzylinder sind zu ihrer Versorgung mit Druckmittel mit einer Hydraulikversorgungseinrichtung verbunden. Die Hydraulikversorgungseinrichtung enthält Elemente, um einen Anfangsdruck in den Kurzhubzylindern zu ändern. Diese Druckänderung erfolgt vor Beginn der Preßoperation.
Bei dieser mit hohem technischen Aufwand betriebenen Lösung kommen die im Kraftfluß liegenden Funktionselemente durch im praktischen Pressenbetrieb gegebene verschleiß- und/oder fertigungsbedingte geometrische Abweichungen zu unterschiedlichen Zeitpunkten zur Wirkung. Durch die Federwirkung des Druckmittels entstehen nach dem Kontakt des ersten Druckbolzens bis zur Erreichung gleicher Druckbolzenkräfte Kippkräfte auf das gesamte System Stößel - Werkzeug - Druckbolzenplatte.According to EP 0 531 140 A1, a hydraulic cushion assembly for a press is known which is intended to apply a cushion force that is uniform for a workpiece across all pressure bolts. For this purpose, a plurality of short-stroke cylinders that are fluidly connected to one another and whose short-stroke pistons are operatively connected to the pressure bolts are arranged on a pressure-pin plate that can be moved by the die cushion. The short-stroke cylinders are connected to a hydraulic supply device to supply them with pressure medium. The hydraulic supply device contains elements for changing an initial pressure in the short-stroke cylinders. This pressure change takes place before the start of the pressing operation.
In this solution, which is operated with a high level of technical complexity, the functional elements located in the power flow come into effect at different times as a result of wear and / or production-related geometric deviations given in practical press operation. The spring action of the pressure medium creates tipping forces on the entire plunger - tool - pressure pin plate system after the first pressure pin comes into contact until the same pressure pin forces are reached.

Das der Erfindung zugrundeliegende Problem ist, eine Kompensationseinrichtung zu schaffen, die mit einfachen technischen Mitteln sichert, daß alle Druckbolzen die gleiche Kraft übertragen, die Kraftwirkung der Kurzhubzylinder untereinander vor Erreichen des vollen Kraftschlusses zwischen den Funktionselementen nahezu ausgeschlossen und das so erreichte Tragbild aller Druckbolzen reproduzierbar ist. Voraussetzung hierfür ist, daß alle Druckbolzen unter Last die gleiche Stauchung erfahren. Dies wiederum macht zur Bedingung, daß geometrische Abweichungen der im Kraftfluß liegenden Funktionselemente kompensiert werden.The problem underlying the invention is a compensation device to create that with simple technical Averaging ensures that all thrust bolts have the same force transfer the force of the short-stroke cylinder with each other before full adhesion is reached almost excluded between the functional elements and the contact pattern of all pressure bolts achieved in this way is reproducible is. The prerequisite for this is that all pressure bolts under Experience the same compression. This in turn does on the condition that geometric deviations of the in Functional elements lying in the power flow can be compensated.

Erfindungsgemäß wird das durch die im Patentanspruch 1 angegebenen Merkmale erreicht. Weitere Ausgestaltungen der Erfindung sind in den Ansprüchen 2 bis 7 beschrieben.According to the invention by the Claim 1 specified features reached. Further embodiments of the invention are in the Claims 2 to 7 described.

Der Vorteil dieser Lösung besteht darin, daß von Kontaktbis Ziehbeginn alle Geometrieabweichungen der während des Ziehprozesses im Kraftfluß liegenden Funktionselemente kompensiert werden durch nahezu druckloses Verdrängen von Druckmittel aus den zu einem kommunizierenden System zusammengeschlossenen Kurzhubzylindern in den mechanisch begrenzen Raum eines Kompensationszylinders. Dabei werden Kraftwirkungen der Kurzhubzylinder untereinander bis zum Erreichen des vollen Kraftschlusses zwischen Stößel und Ziehkissen oder Blechhalter weitgehend ausgeschlossen. Mit Ziehbeginn sichert das kommunizierende hydraulische System gleichen Druck in allen Kurzhubzylindern und damit die beabsichtigte gleiche Kraft aller Druckbolzen. In Abhängigkeit von der Anzahl der je Werkzeug im Einsatz befindlichen Druckbolzen und von der Summe der geometrischen Abweichung der im Kraftfluß liegenden Funktionselemente ist der mechanisch begrenzte Raum im Kompensationszylinder vorteilhafterweise veränderbar. Ein weiterer Vorteil der Lösung liegt darin, daß zwar alle Druckbolzenpunkte der Druckbolzenplatte mit Kurzhubzylindern belegt sein können, jedoch zweckmäßigerweise nur die nach einer empirischen Ermittlung notwendigen Druckbolzenpunkte im Rahmen des genormten Rasters mit Kurzhubzylindern belegt werden. Während die Anpassung der Anzahl und Lage der Druckbolzen für jedes Werkzeug manuell in der bekannten Form bei Werkzeugwechsel erfolgt, können die nicht notwendigen aber auf der Druckbolzenplatte vorhandenen Kurzhubzylinder drucklos geschaltet und so vom kommunizierenden System abgekoppelt werden. Ebenfalls können die werkzeugspezifisch notwendigen Druckbolzenpunkte mit Druckbolzen belegt werden und die weiterhin vorhandenen Kurzhubkolben der nicht notwendigen Druckbolzenpunkte "blind" weiter betrieben werden. Alternativ können auch alle vorhandenen Kurzhubzylinder betrieben werden und nur die werkzeugspezifisch notwendigen Druckbolzenpunkte mit Druckbolzen belegt werden. Die Ausrüstung kann auch so gestaltet werden, daß beim Werkzeugwechsel die einzelnen Kurzhubzylinder in ihrer Zuordnung zu den Druckbolzen verschiebbar bzw. ab- und nachrüstbar sind. Bei Veränderung der Anzahl der Druckbolzen und/oder Geometrieabweichungen der Funktionselemente ist eine Volumenänderung des Kompensationsraumes im Kompensationszylinder zweckmäßig. Die Kurzhubzylinder können auch mit unterschiedlichen Wirkflächen ausgebildet werden.The advantage of this solution is that from contact to All geometrical deviations of the during the Drawing process functional elements in the power flow are compensated for by almost pressure-free displacement of Pressure medium from the to a communicating system merged short-stroke cylinders in the mechanically limit the space of a compensation cylinder. In doing so Force effects of the short stroke cylinders with each other up to Reaching full adhesion between the plunger and Die cushion or sheet holder largely excluded. With The communicating hydraulic system secures the start of drawing same pressure in all short stroke cylinders and thus the intended same force of all pressure bolts. In Depends on the number of tools used per tool located pushpin and the sum of the geometrical deviation of those in the power flow Functional elements is the mechanically limited space in the Compensation cylinder advantageously changeable. A Another advantage of the solution is that everyone Push pin points of the push pin plate with short stroke cylinders can be occupied, but expediently only those necessary according to an empirical determination Push pin points within the framework of the standardized grid Short stroke cylinders are occupied. While adjusting the Number and position of the pressure bolts for each tool manually takes place in the known form when changing tools the not necessary but on the push pin plate Existing short stroke cylinders are depressurized and so from communicating system can be disconnected. Likewise can determine the pressure pin points required for the specific tool to be covered with pressure bolts and the ones that still exist Short stroke piston of the unnecessary pressure pin points "blind" continue to operate. Alternatively, you can all existing short stroke cylinders are operated and only the pressure pin points required for the specific tool Pressure bolts are occupied. The equipment can also do so be designed so that the individual when changing tools Short stroke cylinders in their assignment to the pressure bolts can be moved or removed and retrofitted. When change the number of pressure bolts and / or geometry deviations of the functional elements is a change in volume of the Compensation room expedient in the compensation cylinder. The short stroke cylinders can also be used with different Active areas are formed.

Die Erfindung soll nachstehend an einem Ausführungsbeispiel näher erläutert werden. Die zugehörigen Zeichnungen zeigen:

Fig. 1:
Prinzipdarstellung der Kraftübertragung zwischen Stößel und Ziehkissen einer mechanischen Presse bei Kontaktbeginn mit zusätzlich angegebener Pressenstößelstellung nach Figur 2.
Fig. 2:
Prinzipdarstellung der Kraftübertragung zwischen Stößel und Ziehkissen einer mechanischen Presse bei Ziehbeginn mit zusätzlich angegebener Pressenstößelstellung nach Figur 1.
Fig. 3:
Draufsicht auf eine Druckbolzenplatte mit Darstellung der Druckbolzenpunkte für verschiedene Werkzeuge
Fig: 4:
Schnitt A - A aus Fig. 3
The invention will be explained in more detail below using an exemplary embodiment. The associated drawings show:
Fig. 1:
Schematic diagram of the power transmission between the ram and die cushion of a mechanical press at the start of contact with the press ram position specified additionally according to FIG. 2.
Fig. 2:
Schematic representation of the power transmission between the ram and die cushion of a mechanical press at the start of drawing with the press ram position specified additionally according to FIG. 1.
Fig. 3:
Top view of a push pin plate showing the push pin points for different tools
Fig: 4:
Section A - A from FIG. 3

Der Pressenstößel 1 mit Oberwerkzeug einer mechanischen oder hydraulischen Presse kommt mit dem auf dem Schiebetisch 2 angeordneten Unterwerkzeug in bekannter Weise gemäß Fig. 1 in Wirkverbindung. Zur Verdeutlichung des Zusammenhanges zwischen geometrischer Abweichung und Kraftwirkung der im Kraftfluß liegenden Funktionselemente ist auf die Darstellung von Ober- und Unterwerkzeug verzichtet. Durch Geometrieabweichungen der während des Ziehprozesses im Kraftfluß liegenden Funktionselemente, die sich in der Summe in der Längendifferenz 8, je Druckbolzen 7 mit y1 bis yn bezeichnet, ausdrücken, kommt es nicht gleichzeitig zum Kontakt aller diesbezüglichen Bauteile. In diesem Ausführungsbeispiel steht die im Pressentisch 4 geführte Druckbolzenplatte 3 in bekannter Weise mit einem auf der Traverse 19 angeordneten Ziehkissen in Wirkverbindung. Dazu wird der Ziehkissenkolben 18 mit der Ziehkissenkraft 23 beaufschlagt. Auf der Druckbolzenplatte 3 sind die Kurzhubzylinder 5 angeordnet, die über Verbindungsleitungen 20 untereinander fließverbunden sind. Jedem Kurzhubkolben 6 ist ein Druckbolzen 7 zuordenbar. Die fließverbundenen Kurzhubzylinder 5 sind über eine Verbindungsleitung 14 mit einem Kompensationsraum 22 eines vorzugsweise starr an der Druckbolzenplatte 3 angeordneten Kompensationszylinders 10 verbunden. Diese Verbindungsleitung 14 ist gleichzeitig über ein Wegeventil 17, zu dem ein Druckbegrenzungsventil 24 parallel geschaltet ist, an einer im Kompensationszylinder 10 integrierten Druckmittelbehälter 16 angeschlossen. Über ein Wegeventil 21 steht der Druckmittelbehälter 16 mit einer Druckregulierungseinrichtung 15 in Wirkverbindung. An der mit dem Kompensationskolben 11 starr verbundenen Kolbenstange ist eine verstellbare Hubbegrenzung 13 angeordnet. Vor der Einleitung von Kraft vom Pressenstößel 1 über das Oberwerkzeug in die Druckbolzen 7 befinden sich die Kurzhubkolben 6 in ihrer oberen, mechanisch begrenzten Ausgangsstellung, in die sie durch Federkraft gebracht und gehalten werden. Dabei kann die Feder mechanisch sein oder durch pneumatischen Druck erzeugt werden. The press ram 1 with the upper tool of a mechanical or hydraulic press comes into operative connection with the lower tool arranged on the sliding table 2 in a known manner according to FIG. 1. In order to clarify the relationship between the geometric deviation and the force effect of the functional elements lying in the force flow, the upper and lower tools are not shown. Due to geometrical deviations of the functional elements lying in the power flow during the drawing process, which in total are expressed in terms of the length difference 8, each of the pressure bolts 7 with y 1 to y n , there is no simultaneous contact of all relevant components. In this exemplary embodiment, the pressure pin plate 3 guided in the press table 4 is operatively connected in a known manner to a die cushion arranged on the cross member 19. For this purpose, the die cushion piston 18 is acted upon by the die cushion force 23. The short-stroke cylinders 5 are arranged on the pressure pin plate 3 and are flow-connected to one another via connecting lines 20. A pressure pin 7 can be assigned to each short-stroke piston 6. The flow-connected short-stroke cylinders 5 are connected via a connecting line 14 to a compensation chamber 22 of a compensation cylinder 10 which is preferably rigidly arranged on the pressure pin plate 3. This connecting line 14 is simultaneously connected via a directional valve 17, to which a pressure relief valve 24 is connected in parallel, to a pressure medium container 16 integrated in the compensation cylinder 10. The pressure medium container 16 is operatively connected to a pressure regulating device 15 via a directional valve 21. An adjustable stroke limiter 13 is arranged on the piston rod rigidly connected to the compensation piston 11. Before the introduction of force from the press ram 1 via the upper tool into the pressure bolts 7, the short-stroke pistons 6 are in their upper, mechanically limited starting position, into which they are brought and held by spring force. The spring can be mechanical or generated by pneumatic pressure.

Ebenfalls durch Federkraft erzeugt, befindet sich der Kompensationskolben 11 in seiner mechanischen, unteren Endlage. Mit dem Erstkontakt zwischen den antreibenden System von Pressenstößel 1 mit Oberwerkzeug und dem ruhenden Ziehkissen mit der Druckbolzenplatte 3, dem Ziehkissenkolben 18, den Kurzhubzylindern 5 und den Druckbolzen 7 kommt es zur Verschiebung des diesbezüglichen Kurzhubkolbens 6 um den Verdrängerhub 9. Dieser Verdrängerhub 9 ist je Kurzhubzylinder 5 unterschiedlich und mit x1 bis xn bezeichnet. In der Reihenfolge der jeweiligen Geometrieabweichung bzw. Längendifferenz 8 folgen bis Ziehbeginn alle Druckbolzen 7 und verdrängen Druckmittel über die Verbindungsleitung 20 und 14 in den Kompensationsraum 22 des Kompensationszylinders 10. Durch die Druckmittelverdrängung aus den Kurzhubzylindern 5 erfolgt die Verschiebung des Kompensationskolbens 11 um den Kompensationshub 12. Dieser Kompensationshub 12 und damit die Summe des aus den Kurzhubzylindern 5 verdrängten Druckmittels, wird durch die verstellbare Hubbegrenzung 13 bestimmt. Durch die mechanisch begrenzte Volumenaufnahme im Kompensationszylinder 10 wird der Verdrängerhub 9 der Kurzhubkolben 6 in Ziehrichtung unterbrochen. Damit erfolgt der weitere Antrieb der Druckbolzen gegen die wirkende Ziehkissenkraft 23, die sich über die Traverse 19 am Pressentisch 4 abstützt. Die qualitative Lage der Funktionselemente bei Ziehbeginn ist in Figur 2 dargestellt. Durch die Verbindungsleitung 20 sind alle Kurzhubzylinder 5 zu einem kommunizierenden System zusammengeschlossen, so daß die in Schwimmstellung befindlichen Kurzhubkolben 6 vollen Formschluß der im Kraftfluß liegenden Funktionselemente herstellen und sich dadurch gleicher Druck in allen Kurzhubzylindern 5 einstellt. Diese Wirkung bleibt über den gesamten Ziehhub erhalten. Dabei befindet sich das Wegeventil 17 von der Verbindungsleitung 14 in Richtung Druckmittelbehälter 16 in sperrender Stellung. Parallel zum Wegeventil 17 ist das Druckbegrenzungsventil 24 angeordnet zur Absicherung des Hydrauliksystems vor Überlastung. Zur Realisierung "weicher" Druckübergänge bei Ziehbeginn kann das Wegeventil 17 auch als Stetigventil ausgebildet sein. Mit Entlastung der Druckbolzen 7 nach dem Ziehvorgang erfolgt die Rückförderung des Druckmittels aus dem Kompensationsraum 22 in die Kurzhubzylinder 5, wodurch die Kurzhubkolben 6 ihre Ausgangslage erreichen. Zur Rückführung der Kurzhubkolben 6 und des Kompensationskolbens 11 in ihre Ausgangslage erfolgt die Beaufschlagung des Druckmittels mit Pneumatikdruck über die Druckregeleinrichtung 15 und das Wegeventil 21. Der im Druckmittelbehälter 16 anliegende Druck bewirkt durch die Differenzfläche eine entsprechende Kraft, die den Rückfluß des Druckmittels aus dem Kompensationsraum 22 gewährleistet.Also generated by spring force, the compensation piston 11 is in its mechanical, lower end position. With the first contact between the driving system of press ram 1 with the upper tool and the stationary drawing cushion with the pressure pin plate 3, the drawing cushion piston 18, the short-stroke cylinders 5 and the pressure pin 7, the relevant short-stroke piston 6 is displaced by the displacement stroke 9. This displacement stroke 9 is in each case Short stroke cylinder 5 different and designated x 1 to x n . In the order of the respective geometry deviation or length difference 8, all pressure bolts 7 follow until the start of drawing and displace pressure medium via the connecting lines 20 and 14 into the compensation chamber 22 of the compensation cylinder 10. The pressure piston is displaced from the short-stroke cylinders 5 and the compensation piston 11 is displaced by the compensation stroke 12 This compensation stroke 12 and thus the sum of the pressure medium displaced from the short stroke cylinders 5 is determined by the adjustable stroke limiter 13. Due to the mechanically limited volume absorption in the compensation cylinder 10, the displacement stroke 9 of the short-stroke piston 6 is interrupted in the drawing direction. The pressure bolts are thus driven further against the acting die cushion force 23, which is supported on the press table 4 via the crossmember 19. The qualitative position of the functional elements at the start of drawing is shown in FIG. 2. Through the connecting line 20, all short-stroke cylinders 5 are combined to form a communicating system, so that the short-stroke pistons 6 in the floating position produce full positive locking of the functional elements located in the power flow, and the same pressure is thus set in all short-stroke cylinders 5. This effect is maintained over the entire drawing stroke. The directional control valve 17 is located in the blocking position from the connecting line 14 in the direction of the pressure medium container 16. The pressure relief valve 24 is arranged parallel to the directional control valve 17 to protect the hydraulic system against overload. In order to realize "soft" pressure transitions at the start of drawing, the directional valve 17 can also be designed as a continuous valve. When the pressure bolts 7 are relieved after the drawing process, the pressure medium is returned from the compensation space 22 into the short-stroke cylinders 5, whereby the short-stroke pistons 6 reach their starting position. To return the short-stroke piston 6 and the compensation piston 11 to their starting position, the pressure medium is acted upon by pneumatic pressure via the pressure control device 15 and the directional control valve 21. The pressure in the pressure medium container 16 causes a corresponding force through the differential area, which causes the pressure medium to flow back from the compensation chamber 22 guaranteed.

Wie aus Figur 3 ersichtlich, besitzt die Druckbolzenplatte 3 eine genormte Anzahl von Druckbolzenpunkten 25. Der Bedarf dieser einzelnen Druckbolzenpunkte 25 je Werkzeug ist bekanntlich sehr unterschiedlich. Neben den Möglichkeiten des Bestückens aller oder der jeweils nur für ein Werkzeug erforderlichen Druckbolzenpunkte 25 mit Kurzhubzylindern 5 wird vorgeschlagen, nach einer empirisch festgestellten notwendigen Druckbolzenpunktebelegung für Werkzeuge in einem bestimmten Zeitraum Kurzhubzylinder 5 zu betreiben und nur die nach jeweiligem Werkzeug erforderlichen Druckbolzenpunkte 25 mit Druckbolzen 7 auszustatten oder die jeweils nicht erforderlichen Druckbolzenpunkte 25 durch "Drucklosschalten" der nicht benötigten Kurzhubzylinder 5 außer Betrieb zu setzen. Dabei ist die Herausnahme der Druckbolzen aus der nicht dargestellten Werkzeugaufspannplatte keine Bedingung. Für den Anwendungsfall "Drucklosschalten" ist jedem Kurzhubzylinder 5 ein Wegeventil 26 und zusätzlich allen Kurzhubzylindern 5 gemeinsam das Wegeventil 27 zugeordnet. Die Wegeventile 26 und 27 sind zwischen den Kurzhubzylindern 5 und dem Druckmittelbehälter 16 angeordnet und in Reihe geschaltet. Sie ermöglichen, daß die für ein Werkzeug nicht benötigten Kurzhubzylinder 5 druckentlastet und damit außer Betrieb gesetzt werden. Bei Bedarf kann die Anzahl der Kurzhubzylinder 5 für jedes Werkzeug angepaßt werden. Dazu sind die Kurzhubzylinder 5 in ihrer räumlichen Anordnung veränderbar bzw. ab- und nachrüstbar. Bei Veränderung der Anzahl der Druckbolzen 7 und/oder der Teilegeometrie bzw. der Längendifferenz 8 ist eine Volumenänderung des Kompensationsraumes 22 mittels der Hubbegrenzung 13 zweckmäßig.As can be seen from Figure 3, the pressure pin plate 3 a standardized number of pressure pin points 25. The Need these individual pressure pin points 25 per tool is known to be very different. In addition to the possibilities the assembly of all or only for one Tool required pressure pin points 25 with short-stroke cylinders 5 is suggested, according to an empirical determined necessary pin assignment for Tools in a certain period of time short-stroke cylinder 5 too operate and only according to the respective tool required pressure pin points 25 with pressure pin 7 equip or those that are not required Push pin points 25 by "depressurizing" the not to put the required short stroke cylinder 5 out of operation. Here is the removal of the pressure bolts from the tool platen shown no condition. For the use case "depressurization" is everyone Short stroke cylinder 5 a directional control valve 26 and in addition all Short stroke cylinders 5 jointly assigned the directional control valve 27. The directional control valves 26 and 27 are between the short-stroke cylinders 5 and the pressure medium container 16 arranged and connected in series. They allow that for a Tool not required short stroke cylinder 5 relieved of pressure and thus be put out of operation. If necessary, the Number of short-stroke cylinders 5 adapted for each tool become. For this purpose, the short-stroke cylinders 5 are spatially Arrangement can be changed or removed and retrofitted. At Change in the number of pressure bolts 7 and / or Part geometry or the length difference 8 is one Volume change of the compensation space 22 by means of Stroke limitation 13 expedient.

Claims (7)

  1. Clamping arrangement between the upper and lower tool of a press for achieving the sheet holding force, with a thrust bolt plate (3) on which is arranged a plurality of continuously interconnected short-stroke cylinders (5) of which the short-stroke pistons (6) each cooperate with thrust bolts (7), wherein the thrust bolts (7) in cooperation can fix the sheet which is to be shaped between upper and lower tool, characterized in that the pressure chambers, located on the sides of the short-stroke pistons (6) remote from the pressure bolts (7), of the short-stroke cylinders (5) cooperate with a compensating cylinder (10) in such a way that the pressure medium displaced in the short-stroke cylinders (5) via the displacement stroke (9) before the beginning of drawing by the action of force in the thrust bolts (7) is received in the compensating chamber (22) of the compensating cylinder (10), and in that the pressure is identical in all pressure chambers.
  2. Clamping arrangement according to claim 1, characterized in that, for each thrust bolt point (25) provided in a tool fixing plate according to the various tools, a respective short-stroke cylinder (5) can be arranged on the thrust bolt plate (3).
  3. Clamping arrangement according to claim 1, characterized in that the short-stroke cylinders (5) can be varied in their arrangement on the thrust bolt plate (3) according to the tool requirements.
  4. Clamping arrangement according to one of claims 1 to 3, characterized in that each short-stroke cylinder (5) can be switched separately without pressure.
  5. Clamping arrangement according to one of claims 1 to 4, characterized in that the volume of the compensating chamber (22) and therefore the compensating stroke (12) can be varied by an adjustable stroke limiter (13).
  6. Clamping arrangement according to one of claims 1 to 5, characterized in that the short-stroke cylinder (5) and the compensating cylinder (10) are arranged in the same moving system and do not perform a movement relative to one another.
  7. Clamping arrangement according to one of claims 1 to 6, characterized in that, for achieving "soft" changes of pressure at the beginning of drawing, a direction-control valve (17) designed as a continuous valve is arranged between the connecting line leading to the pressure chambers and a pressure medium container (16).
EP95117213A 1994-11-23 1995-11-02 Clamping device between the upper and lower tool of a press Expired - Lifetime EP0713735B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4441562A DE4441562A1 (en) 1994-11-23 1994-11-23 Length compensation device in a clamping device between the upper and lower tool of a press
DE4441562 1994-11-23

Publications (2)

Publication Number Publication Date
EP0713735A1 EP0713735A1 (en) 1996-05-29
EP0713735B1 true EP0713735B1 (en) 1999-01-13

Family

ID=6533869

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95117213A Expired - Lifetime EP0713735B1 (en) 1994-11-23 1995-11-02 Clamping device between the upper and lower tool of a press

Country Status (3)

Country Link
EP (1) EP0713735B1 (en)
DE (2) DE4441562A1 (en)
ES (1) ES2126199T3 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2991608B1 (en) * 2012-06-07 2014-06-20 Peugeot Citroen Automobiles Sa FLANK STRIPE FOR A STRIPPING PRESS INCLUDING A PRESS CUSHION ACCOMMODATION DIALING INDICATOR.

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3476524D1 (en) * 1984-06-29 1989-03-09 Schuler Gmbh L Drawing device in a press
DE3735581C1 (en) * 1987-10-21 1988-05-11 Daimler Benz Ag Press for pulling sheet metal parts
DD298484A5 (en) * 1990-10-02 1992-02-27 Umformtechnik Erfurt Gmbh,De HYDRAULIC LEAD HOLDER FOR SIMPLE-ACTING PRESSES
EP0531140B1 (en) 1991-09-04 1995-07-26 Toyota Jidosha Kabushiki Kaisha Hydraulic cushioning system for press, having hydraulic power supply including means for adjusting initial pressure to pressure-pin cylinders
CA2077510C (en) * 1991-09-04 1997-01-28 Kazunari Kirii Hydraulic cushioning system for press, having shut-off valve for disconnection of pressure-pin cylinders from power supply upon contact of movable die with workpiece
JP2722937B2 (en) * 1992-04-07 1998-03-09 トヨタ自動車株式会社 Wrinkle press load measuring device for press machine
EP0596697B1 (en) * 1992-11-05 1997-04-09 Toyota Jidosha Kabushiki Kaisha Device and method for measuring and adjusting pressing load values on a press

Also Published As

Publication number Publication date
EP0713735A1 (en) 1996-05-29
DE59504805D1 (en) 1999-02-25
DE4441562A1 (en) 1996-05-30
ES2126199T3 (en) 1999-03-16

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