EP0748662B1 - Method for controlling a tube bending machine - Google Patents

Method for controlling a tube bending machine Download PDF

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Publication number
EP0748662B1
EP0748662B1 EP96109222A EP96109222A EP0748662B1 EP 0748662 B1 EP0748662 B1 EP 0748662B1 EP 96109222 A EP96109222 A EP 96109222A EP 96109222 A EP96109222 A EP 96109222A EP 0748662 B1 EP0748662 B1 EP 0748662B1
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EP
European Patent Office
Prior art keywords
bending
pipe
actual value
pressures
cylinder
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EP96109222A
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German (de)
French (fr)
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EP0748662A1 (en
Inventor
Rigobert Dipl.-Ing. Schwarze
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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
    • B21D7/00—Bending rods, profiles, or tubes
    • B21D7/02—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment
    • B21D7/024—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member
    • B21D7/025—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member and pulling or pushing the ends of the work

Definitions

  • the invention relates to a method for controlling a Pipe bending machine and a pipe bending machine.
  • DE 23 04 838 C2 describes a pipe bending process where the angle of rotation of the bending template and the Position of the slide rail can be determined. Corresponding the difference between the upsetting speed and the peripheral speed of the bending template an actual value is determined, which with a corresponding Setpoint value of the speed differences compared becomes.
  • the comparison result is a servo valve fed one of the two hydraulic drives influenced. There is mutual coordination of feed speed and bending speed, that are equal to each other or to a certain one Ratio can be set.
  • the invention has for its object a control method specify with which it is possible to use pipes with to bend gently with high accuracy and dimensional accuracy.
  • the method according to the invention provides force control for the feed force with which the slide rail is advanced will, before. With this force control a Setpoint value of the feed force depending on the Angle of rotation of the bending template and the actual value the feed force becomes according to the setpoint regulated. According to the programmed course of the The setpoint is dependent on the current bending angle the feed force of the slide rail changed.
  • the System is particularly suitable for thick-walled pipes and especially for pressure bending technology, where the unbent Pipe section in the direction during the bending process is pressed on the bending template, as well as for Extreme areas. As a result of the special pressure control the flow of force within the tube walls is influenced in a targeted manner. Variations in the material, its homogeneity and strength only affect the end product very low.
  • control method according to the invention are therefore minor Wall thickness rejuvenation, low ovality and less Tool wear.
  • One consequence of this is the possibility the reduction in pipe wall thickness, and thus a material saving, with the same strength of the finished pipe.
  • They are also suitable according to the method bent tubes excellent for a subsequent Hydroforming, where there is high uniformity of the starting product arrives.
  • the actual value of the feed force is thereby preferred determined that the pressures in the cylinder on both sides of the piston can be detected and from the pressures below Taking into account the sizes of the two piston surfaces the actual value of the feed force is determined. For this are only pressure sensors on the hydraulic cylinder required for the slide rail feed. Alternatively there is the possibility of a force sensor in to install the slide rail feed, however the stability of the slide rail feed is reduced.
  • the pressures in the cylinder are expediently increased both sides of the piston changed in opposite directions to each other. This means that if the Feed pressure the back pressure is reduced. Thereby there is the possibility of the maximum pump pressure for to take full advantage of the feed.
  • the method according to the invention does not necessarily have to be for a tube bending process from start to finish be performed. There is also the possibility the bending process partly according to the synchronous process and only in the critical areas with the invention Process, i.e. through force control.
  • the invention further relates to a pipe bending machine.
  • a device for recording the actual value the feed force applied by the cylinder provided and there is a controller that the Actual value of the feed force according to a setpoint readjusted depending on a setpoint generator from that of the position transmitter of the bending template supplied bending angle is generated.
  • the pipe bending machine shown schematically in Fig. 1 has one on a machine table (not shown) rotatably mounted bending template 10.
  • the with a vertical axis of rotation 11 arranged bending template 10 has essentially the shape of a cylindrical body, a bending groove 12 is formed on the peripheral surface thereof which is the cross section of the pipe to be bent 13 takes up about half.
  • a counter jaw 14 is attached with one Clamping jaw 15 cooperates to jointly pipe 13 to grasp and clamp for the bending process.
  • the clamping jaw 15 is attached to a swivel arm 16, which is pivotable about an axis, which with the axis of rotation 11 of the bending template 10 coincides.
  • the clamping jaw 15 is radial on this swivel arm 16 movable to clamp or release the pipe.
  • the unbent portion 13a of the tube 13 is one Pressing device 17 supported.
  • the pressing device has a carriage 18 which in the direction of the double arrow 19 transversely to the pipe section 13 is movable.
  • the carriage 18 carries a lower carriage 20, which is longitudinal to the unbent Pipe section 13a, that is in the direction of the double arrow 21, is movable, and a cylinder 22 for moving of the lower carriage 20.
  • the cylinder 22 is on the Carriage 18 fixed and in it is the piston 23 movable, the piston rod 24 on the lower slide 20 attacks to move it.
  • the cylinder 22 has a working chamber 25 and a return stroke chamber 26, which are separated by the piston 23.
  • a position transmitter 30 is arranged on the bending template 10.
  • the position transmitter 30 has, for example a rotary encoder on which the rotational position of the Bending template 10 indicates.
  • the bending template 10 is rotated by a (hydraulic) drive 31.
  • a slide rail 32 which of the the side facing away from the bending template against the pipe 13 presses and the unbent pipe section 13a at Supports the bending process. Furthermore is on the lower carriage 20 a thrust element 35 attached to the rear Part of the unbent pipe section 13a attacks.
  • the push element 35 can have a jaw 36, to clamp the pipe section 13a firmly. It is so trained that it acts on the tube without sliding.
  • the Thrust element 35 and the jaw 36 are for that Pressure bending required. If no pressure bending is applied the feed force is determined exclusively by the Transfer the slide rail 32 to the tube 13.
  • the straight tube is between the clamping jaw 15 and counter jaw 14 clamped. Then it will be the bending template 10 according to a predetermined program rotated, pulling the tube around the bending template and at the same time the straight pipe section 13a is moved forward. During the bending process the lower slide 20 is parallel to the pipe section 13a advanced by the hydraulic cylinder 22.
  • Position A connects valve 42 to lines 40 and 41 with a switching valve 43, which with a pump 44 and a sump 45 is connected and between one Pass position and a blocking position switched can be.
  • the position B of the valve 42 is used for the fast feed and position C for the return stroke piston 23.
  • a pressure transducer 46 is connected to line 40, which generates a current signal that corresponds to the hydraulic Pressure in line 40 corresponds.
  • a pressure transducer 47 is connected, the one Current signal generated that the hydraulic pressure in the Line 41 corresponds.
  • the outputs of the two pressure transducers 46 and 47 are connected to a controller 48, to the control line 39 the control signal for the Differential valve 42 delivers.
  • the controller 48 calculates from the pressures in chambers 25 and 26 and the sizes of the two piston surfaces A1 and A2 the actual value Fi Feeding force acting on the slide 20.
  • the controller 48 is also provided with a setpoint generator 49 connected, which is a target value Fs of the feed force delivers to the controller 48.
  • This setpoint Fs the Feed force varies depending on the angle of rotation ⁇ of the bending template 10, the position transmitter 30th is delivered.
  • Fig. 3 shows the control scheme.
  • the setpoint generator 49 contains several curves representing the setpoint Fs of the feed force depending on the angle of rotation ⁇ of the bending template Specify 10. Can on the setpoint generator the desired curve can be selected. Further can the value ⁇ for the start on the setpoint generator and the end of pipe machining can be entered.
  • the Setpoint generator 49 then delivers depending on ⁇ the associated setpoint Fs, of which in a Subtractor 50 the actual value Fi is subtracted.
  • the Subtraction result is fed to the controller 48 which for example a PID controller.
  • This controller delivers via the control line 39 a control signal to the Control path 51, which here consists of differential valve 42 and the cylinder 22 (Fig. 2).
  • the pressure P1 in the line 40 and the pressure P2 in the Line 41 are the respective converter 46 and 47th fed.
  • the output signal of converter 46 is shown in a multiplier 52 multiplied by a value, which corresponds to the area A1 of the piston 23.
  • the output signal of the converter 47 is in a multiplier 53 multiplied by a value equal to the size of the Surface A2 of the piston 23 corresponds.
  • the multiplier 52 thus forms the product P1 x A1 and the multiplier 53 forms the product P2 x A2. Any of these products is a measure of one of the two opposing forces interact with each other on the piston 23.
  • a subtractor 54 subtracts the two products from each other, so that the actual value Fi of the feed force arises. This actual value is in the subtractor 50 from the Setpoint Fs subtracted to the input signal for the Form controller 48.
  • the output signals of the two converters 46 and 47 are an error evaluation 55 fed an alarm signal generated or stops the pipe bending machine if the pressures P1 and P2 show abnormalities. It can also e.g. Total failures of the sensor are shown.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)

Description

Die Erfindung betrifft ein Verfahren zur Steuerung einer Rohrbiegemaschine sowie eine Rohrbiegemaschine.The invention relates to a method for controlling a Pipe bending machine and a pipe bending machine.

Beim Biegen von Rohren wird das Rohr mit einer Spannbacke seitlich gegen eine Biegeschablone gedrückt, die anschließend unter Mitnahme der Spannbacke gedreht wird. Beim Drehen der Biegeschablone wird das Rohr um die Biegeschablone herum gebogen. Der ungebogene Rohrabschnitt stützt sich dabei an einer Gleitschiene ab. Auf die Gleitschiene wirkt eine Vorschubvorrichtung ein, die die Gleitschiene während des Biegevorganges vorschiebt. Eine besondere Bedeutung kommt der gegenseitigen Abstimmung zwischen der Drehbewegung der Biegeschablone und der Vorschubbewegung der Gleitschiene zu. Wenn die Gleitschiene zu schnell oder zu langsam vorgeschoben wird, können an dem Rohr Risse, Wellungen oder ovale Verformungen entstehen. Ferner können sich Bereiche unterschiedlicher Wandstärke ausbilden. When bending pipes, the pipe is clamped with a jaw pressed laterally against a bending template that then turned with the jaw becomes. When the bending template is turned, the pipe is turned over the bending template bent around. The unbent pipe section is supported on a slide rail. A feed device acts on the slide rail one that the slide rail during the bending process advances. Mutual is of particular importance Coordination between the rotation of the bending template and the feed movement of the slide rail to. If the slide is too fast or too slow cracks, corrugations on the pipe or oval deformations. Furthermore, can Form areas of different wall thickness.

In DE 23 04 838 C2 ist ein Rohrbiegeverfahren beschrieben, bei dem der Drehwinkel der Biegeschablone und die Position der Gleitschiene ermittelt werden. Entsprechend der Differenz zwischen der Stauchgeschwindigkeit und der Umfangsgeschwindigkeit der Biegeschablone wird ein Istwert ermittelt, der mit einem entsprechenden Sollwert der Geschwindigkeitsdifferenzen verglichen wird. Das Vergleichsergebnis wird einem Servoventil zugeleitet, das einen der beiden hydraulischen Antriebe beeinflußt. Hierbei erfolgt eine gegenseitige Abstimmung von Vorschubgeschwindigkeit und Biegegeschwindigkeit, die einander gleichgemacht oder auf ein bestimmtes Verhältnis eingestellt werden.DE 23 04 838 C2 describes a pipe bending process where the angle of rotation of the bending template and the Position of the slide rail can be determined. Corresponding the difference between the upsetting speed and the peripheral speed of the bending template an actual value is determined, which with a corresponding Setpoint value of the speed differences compared becomes. The comparison result is a servo valve fed one of the two hydraulic drives influenced. There is mutual coordination of feed speed and bending speed, that are equal to each other or to a certain one Ratio can be set.

In DE 41 29 478 A1 nächster Stand der Technik ist ein Verfahren zur Steuerung einer Rohrbiegemaschine beschrieben, das als Synchronvorschub bezeichnet werden kann. Hierbei werden die Drehposition der Biegeschablone und die Vorschubposition der Gleitschiene ermittelt. Die so gewonnenen Meßgrößen werden miteinander verglichen. Der Differenzwert steuert einen Druckregler, der den der Vorschubeinrichtung zuzuführenden Druck verändert. Wenn bei einem derartigen Steuerverfahren die Ist-Position einmal hinter der Soll-Position herläuft, muß, um wieder synchron fahren zu können, die einwirkende Vorschubkraft ständig erhöht werden. Da hierbei keine Rücksicht auf das Fließverhalten des Rohrmaterials genommen wird, besteht die Gefahr der Faltenbildung. Ferner besteht die Gefahr, daß die Gleitschiene an dem Rohr rutscht, weil die auftretende Vorschubkraft die Reibungskraft der Gleitschiene an der Rohroberfläche übersteigt. DE 41 29 478 A1 closest prior art is a method for controlling a Pipe bending machine described as the synchronous feed can be designated. Here, the rotational position the bending template and the feed position the slide rail determined. The measured variables obtained in this way are compared with each other. The difference value controls a pressure regulator, that of the feed device pressure to be supplied changed. If with such Control procedure the actual position once behind the Target position runs up, must drive in sync again to be able to constantly increase the acting feed force become. Because here no consideration of the flow behavior of the pipe material, there is a risk the formation of wrinkles. There is also a risk that the Slide rail slips on the tube because of the occurring Feed force the frictional force of the slide rail on the Pipe surface exceeds.

Der Erfindung liegt die Aufgabe zugrunde, ein Steuerverfahren anzugeben, mit dem es möglich ist, Rohre mit hoher Genauigkeit und Maßhaltigkeit schonend zu biegen.The invention has for its object a control method specify with which it is possible to use pipes with to bend gently with high accuracy and dimensional accuracy.

Die Lösung dieser Aufgabe erfolgt erfindungsgemäß mit den Merkmalen des Verfahrensanpruchs 1 und des Vorrichtungsanspruch 4.This object is achieved with the invention the features of method claim 1 and Device claim 4.

Das erfindungsgemäße Verfahren sieht eine Kraftregelung für die Vorschubkraft, mit der die Gleitschiene vorgeschoben wird, vor. Bei dieser Kraftregelung wird ein Sollwert der Vorschubkraft in Abhängigkeit von dem Drehwinkel der Biegeschablone vorgegeben und der Istwert der Vorschubkraft wird entsprechend dem Sollwert geregelt. Entsprechend dem programmierten Verlauf des Sollwerts wird in Abhängigkeit vom momentanen Biegewinkel die Vorschubkraft der Gleitschiene verändert. Das System eignet sich besonders für dickwandige Rohre und speziell für die Druckbiegetechnik, bei der der ungebogene Rohrabschnitt während des Biegevorganges in Richtung auf die Biegeschablone gedrückt wird, sowie für Extrembereiche. Infolge der speziellen Druckregelung wird der Kraftfluß innerhalb der Rohrwände gezielt beeinflußt. Schwankungen des Materials, seiner Homogenität und Festigkeit wirken sich auf das Endprodukt nur sehr gering aus. Daher sind Ovalität und Faltenbildung an dem gebogenen Rohr ebenfalls gering. Die Vorteile des erfindungsgemäßen Steuerverfahrens sind also geringe Wandstärkenverjüngung, geringe Ovalität und geringer Werkzeugverschleiß. Eine Folge hiervon ist die Möglichkeit der Verringerung der Rohrwandstärke, und damit eine Materialersparnis, bei gleicher Festigkeit des fertigen Rohres. Ferner eignen sich die nach dem Verfahren gebogenen Rohre ausgezeichnet für eine nachfolgende Hydroverformung, bei der es auf hohe Gleichmäßigkeit des Ausgangsprodukts ankommt.The method according to the invention provides force control for the feed force with which the slide rail is advanced will, before. With this force control a Setpoint value of the feed force depending on the Angle of rotation of the bending template and the actual value the feed force becomes according to the setpoint regulated. According to the programmed course of the The setpoint is dependent on the current bending angle the feed force of the slide rail changed. The System is particularly suitable for thick-walled pipes and especially for pressure bending technology, where the unbent Pipe section in the direction during the bending process is pressed on the bending template, as well as for Extreme areas. As a result of the special pressure control the flow of force within the tube walls is influenced in a targeted manner. Variations in the material, its homogeneity and strength only affect the end product very low. Hence ovality and wrinkling also low on the bent tube. The advantages the control method according to the invention are therefore minor Wall thickness rejuvenation, low ovality and less Tool wear. One consequence of this is the possibility the reduction in pipe wall thickness, and thus a material saving, with the same strength of the finished pipe. They are also suitable according to the method bent tubes excellent for a subsequent Hydroforming, where there is high uniformity of the starting product arrives.

Vorzugsweise wird der Istwert der Vorschubkraft dadurch ermittelt, daß die Drücke im Zylinder auf beiden Seiten des Kolbens erfaßt werden und aus den Drücken unter Berücksichtigung der Größen der beiden Kolbenflächen der Istwert der Vorschubkraft bestimmt wird. Hierzu sind lediglich Drucksensoren an dem hydraulischen Zylinder für den Gleitschienenvorschub erforderlich. Alternativ besteht die Möglichkeit, einen Kraftsensor in den Gleitschienenvorschub einzubauen, jedoch wird hierdurch die Stabilität des Gleitschienenvorschubes verringert.The actual value of the feed force is thereby preferred determined that the pressures in the cylinder on both sides of the piston can be detected and from the pressures below Taking into account the sizes of the two piston surfaces the actual value of the feed force is determined. For this are only pressure sensors on the hydraulic cylinder required for the slide rail feed. Alternatively there is the possibility of a force sensor in to install the slide rail feed, however the stability of the slide rail feed is reduced.

Zweckmäßigerweise werden die Drücke im Zylinder auf beiden Seiten des Kolbens gegenläufig zueinander verändert. Dies bedeutet, daß im Falle einer Erhöhung des Vorschubdruckes der Gegendruck verringert wird. Dadurch besteht die Möglichkeit, den maximalen Pumpendruck für den Vorschub vollständig auszunutzen.The pressures in the cylinder are expediently increased both sides of the piston changed in opposite directions to each other. This means that if the Feed pressure the back pressure is reduced. Thereby there is the possibility of the maximum pump pressure for to take full advantage of the feed.

Das erfindungsgemäße Verfahren muß nicht notwendigerweise für einen Rohrbiegevorgang von Anfang bis Ende durchgeführt werden. Es besteht auch die Möglichkeit, das Biegeverfahren teilweise nach dem Synchronverfahren und nur in den kritischen Bereichen mit dem erfindungsgemäßen Verfahren, d.h. durch Kraftregelung, durchzuführen.The method according to the invention does not necessarily have to be for a tube bending process from start to finish be performed. There is also the possibility the bending process partly according to the synchronous process and only in the critical areas with the invention Process, i.e. through force control.

Die Erfindung betrifft ferner eine Rohrbiegemaschine. Hierbei ist eine Einrichtung zur Erfassung des Istwertes der von dem Zylinder aufgebrachten Vorschubkraft vorgesehen und es ist ein Regler vorhanden, der den Istwert der Vorschubkraft entsprechend einem Sollwert nachregelt, der von einem Sollwert-Generator in Abhängigkeit von dem vom Positionsgeber der Biegeschablone gelieferten Biegewinkel erzeugt wird.The invention further relates to a pipe bending machine. Here is a device for recording the actual value the feed force applied by the cylinder provided and there is a controller that the Actual value of the feed force according to a setpoint readjusted depending on a setpoint generator from that of the position transmitter of the bending template supplied bending angle is generated.

Im folgenden wird unter Bezugnahme auf die Zeichnungen ein Ausführungsbeispiel der Erfindung näher erläutert.The following is with reference to the drawings an embodiment of the invention explained in more detail.

Es zeigen:

Fig. 1
eine schematische Darstellung einer Rohrbiegemaschine in Draufsicht,
Fig. 2
ein Blockschaltbild der Regelung des Gleitschienenvorschubes und
Fig. 3
das Regelschema des Gleitschienenvorschubes.
Show it:
Fig. 1
1 shows a schematic illustration of a pipe bending machine in plan view,
Fig. 2
a block diagram of the control of the slide rail feed and
Fig. 3
the control scheme of the slide rail feed.

Die in Fig. 1 schematisch dargestellte Rohrbiegemaschine weist eine auf einem (nicht dargestellten) Maschinentisch drehbar montierte Biegeschablone 10 auf. Die mit vertikaler Drehachse 11 angeordnete Biegeschablone 10 hat im wesentlichen die Form ein zylindrischen Körpers, an dessen Umfangsfläche eine Biegerille 12 ausgebildet ist, die den Querschnitt des zu biegenden Rohres 13 etwa zur Hälfte aufnimmt. An der Biegeschablone 10 ist eine Gegenspannbacke 14 befestigt, mit der eine Spannbacke 15 zusammenwirkt, um gemeinsam das Rohr 13 zu umgreifen und für den Biegevorgang festzuspannen. Die Spannbacke 15 ist an einem Schwenkarm 16 angebracht, der um eine Achse schwenkbar ist, welche mit der Drehachse 11 der Biegeschablone 10 zusammenfällt. The pipe bending machine shown schematically in Fig. 1 has one on a machine table (not shown) rotatably mounted bending template 10. The with a vertical axis of rotation 11 arranged bending template 10 has essentially the shape of a cylindrical body, a bending groove 12 is formed on the peripheral surface thereof which is the cross section of the pipe to be bent 13 takes up about half. On the bending template 10 a counter jaw 14 is attached with one Clamping jaw 15 cooperates to jointly pipe 13 to grasp and clamp for the bending process. The clamping jaw 15 is attached to a swivel arm 16, which is pivotable about an axis, which with the axis of rotation 11 of the bending template 10 coincides.

An diesem Schwenkarm 16 ist die Spannbacke 15 radial bewegbar, um das Rohr einzuspannen oder freizugeben.The clamping jaw 15 is radial on this swivel arm 16 movable to clamp or release the pipe.

Der ungebogene Abschnitt 13a des Rohres 13 wird von einer Nachdrückvorrichtung 17 abgestützt. Die Nachdrückvorrichtung weist einen Schlitten 18 auf, der in Richtung des Doppelpfeiles 19 quer zu dem Rohrabschnitt 13 verfahrbar ist. Der Schlitten 18 trägt einen Unterschlitten 20, der in Längsrichtung zu dem ungebogenen Rohrabschnitt 13a, also in Richtung des Doppelpfeiles 21, verfahrbar ist, sowie einen Zylinder 22 zum Bewegen des Unterschlittens 20. Der Zylinder 22 ist an dem Schlitten 18 fest angeordnet und in ihm ist der Kolben 23 bewegbar, dessen Kolbenstange 24 an dem Unterschlitten 20 angreift, um diesen zu verschieben. Der Zylinder 22 weist eine Arbeitskammer 25 und eine Rückhubkammer 26 auf, die durch den Kolben 23 getrennt sind.The unbent portion 13a of the tube 13 is one Pressing device 17 supported. The pressing device has a carriage 18 which in the direction of the double arrow 19 transversely to the pipe section 13 is movable. The carriage 18 carries a lower carriage 20, which is longitudinal to the unbent Pipe section 13a, that is in the direction of the double arrow 21, is movable, and a cylinder 22 for moving of the lower carriage 20. The cylinder 22 is on the Carriage 18 fixed and in it is the piston 23 movable, the piston rod 24 on the lower slide 20 attacks to move it. The cylinder 22 has a working chamber 25 and a return stroke chamber 26, which are separated by the piston 23.

An der Biegeschablone 10 ist ein Positionsgeber 30 angeordnet. Der Positionsgeber 30 weist beispielsweise einen Drehwinkelkodierer auf, der die Drehposition der Biegeschablone 10 angibt. Die Biegeschablone 10 wird von einem (hydraulischen) Antrieb 31 gedreht.A position transmitter 30 is arranged on the bending template 10. The position transmitter 30 has, for example a rotary encoder on which the rotational position of the Bending template 10 indicates. The bending template 10 is rotated by a (hydraulic) drive 31.

An dem Unterschlitten 20 ist in der Nähe der Biegeschablone 10 eine Gleitschiene 32 angebracht, die von der der Biegeschablone abgewandten Seite her gegen das Rohr 13 drückt und den ungebogenen Rohrabschnitt 13a beim Biegevorgang abstützt. Ferner ist an dem Unterschlitten 20 ein Schubelement 35 angebracht, das an dem rückwärtigen Teil des ungebogenen Rohrabschnitts 13a angreift. Das Schubelement 35 kann eine Klemmbacke 36 aufweisen, um den Rohrabschnitt 13a fest einzuspannen. Es ist so ausgebildet, daß es an dem Rohr gleitfrei angreift. Das Schubelement 35 und die Klemmbacke 36 sind für das Druckbiegen erforderlich. Wenn kein Druckbiegen ausgeübt wird, wird die Vorschubkraft ausschließlich von der Gleitschiene 32 auf das Rohr 13 übertragen.On the lower slide 20 is near the bending template 10 attached a slide rail 32 which of the the side facing away from the bending template against the pipe 13 presses and the unbent pipe section 13a at Supports the bending process. Furthermore is on the lower carriage 20 a thrust element 35 attached to the rear Part of the unbent pipe section 13a attacks. The push element 35 can have a jaw 36, to clamp the pipe section 13a firmly. It is so trained that it acts on the tube without sliding. The Thrust element 35 and the jaw 36 are for that Pressure bending required. If no pressure bending is applied the feed force is determined exclusively by the Transfer the slide rail 32 to the tube 13.

Beim Biegevorgang wird das gerade Rohr zwischen Spannbacke 15 und Gegenspannbacke 14 eingespannt. Dann wird die Biegeschablone 10 nach einem vorgegebenen Programm gedreht, wobei das Rohr um die Biegeschablone herumgezogen wird und gleichzeitig der gerade Rohrabschnitt 13a nach vorne bewegt wird. Während des Biegevorganges wird der Unterschlitten 20 parallel zum Rohrabschnitt 13a durch den hydraulischen Zylinder 22 vorgeschoben.During the bending process, the straight tube is between the clamping jaw 15 and counter jaw 14 clamped. Then it will be the bending template 10 according to a predetermined program rotated, pulling the tube around the bending template and at the same time the straight pipe section 13a is moved forward. During the bending process the lower slide 20 is parallel to the pipe section 13a advanced by the hydraulic cylinder 22.

Gemäß Fig. 2 sind die Leitung 40, die an die Arbeitskammer 25 angeschlossen ist, und die Leitung 41, die an die Rückhubkammer 26 angeschlossen ist, mit einem Regelventil 42 verbunden, das drei unterschiedliche Stellungen A, B und C einnehmen kann. In der dargestellten Stellung A verbindet das Ventil 42 die Leitungen 40 und 41 mit einem Schaltventil 43, das mit einer Pumpe 44 und einem Sumpf 45 verbunden ist und zwischen einer Durchlaßstellung und einer Sperrstellung umgeschaltet werden kann. Die Stellung B des Ventils 42 dient für den schnellen Vorschub und die Stellung C für den Rückhub des Kolbens 23.2 are the line 40 to the working chamber 25 is connected, and the line 41 connected to the return stroke chamber 26 is connected with a control valve 42 connected, the three different positions A, B and C can take. In the illustrated Position A connects valve 42 to lines 40 and 41 with a switching valve 43, which with a pump 44 and a sump 45 is connected and between one Pass position and a blocking position switched can be. The position B of the valve 42 is used for the fast feed and position C for the return stroke piston 23.

In der Stellung A des Regelventils 42 werden die Durchlässe zu den Leitungen 40 und 41 proportional zu dem Signal einer Steuerleitung 39 verändert. Wenn das Signal der Steuerleitung 39 klein ist, sind der zur Leitung 40 führende Drosselquerschnitt und der mit der Leitung 41 verbundene Drosselquerschnitt ebenfalls klein. Je größer das Signal der Steuerleitung 39 ist, um so größer wird der mit der Leitung 40 verbundene Drosselquerschnitt und um so größer wird der mit der Leitung 41 verbundene Drosselquerschnitt. Die Drosselquerschnitte in Zulauf und Ablauf sind stets gleich. Die Drücke zu beiden Seiten des Kolbens werden gegenläufig zueinander verändert.In the position A of the control valve 42, the passages to lines 40 and 41 proportional to that Signal of a control line 39 changed. If the signal the control line 39 is small, are those to the line 40 leading throttle cross section and the one with the Line 41 connected throttle cross section also small. The larger the signal of the control line 39, the larger the one connected to line 40 becomes Throttle cross section and the larger the one with the Line 41 connected throttle cross section. The throttle cross sections the inlet and outlet are always the same. The pressures on both sides of the piston become opposite changed to each other.

An die Leitung 40 ist ein Druckwandler 46 angeschlossen, der ein Stromsignal erzeugt, welches dem hydraulischen Druck in der Leitung 40 entspricht. An die Leitung 41 ist ein Druckwandler 47 angeschlossen, der ein Stromsignal erzeugt, das dem hydraulischen Druck in der Leitung 41 entspricht. Die Ausgänge der beiden Druckwandler 46 und 47 sind mit einem Regler 48 verbunden, der an die Steuerleitung 39 das Steuersignal für das Differentialventil 42 liefert. Der Regler 48 berechnet aus den Drücken in den Kammern 25 und 26 und den Größen der beiden Kolbenflächen A1 und A2 den Istwert Fi der Vorschubkraft, die auf den Schlitten 20 einwirkt.A pressure transducer 46 is connected to line 40, which generates a current signal that corresponds to the hydraulic Pressure in line 40 corresponds. To the management 41, a pressure transducer 47 is connected, the one Current signal generated that the hydraulic pressure in the Line 41 corresponds. The outputs of the two pressure transducers 46 and 47 are connected to a controller 48, to the control line 39 the control signal for the Differential valve 42 delivers. The controller 48 calculates from the pressures in chambers 25 and 26 and the sizes of the two piston surfaces A1 and A2 the actual value Fi Feeding force acting on the slide 20.

Der Regler 48 ist ferner mit einem Sollwert-Generator 49 verbunden, welcher einen Sollwert Fs der Vorschubkraft an den Regler 48 liefert. Dieser Sollwert Fs der Vorschubkraft variiert in Abhängigkeit von dem Drehwinkel α der Biegeschablone 10, der vom Positionsgeber 30 geliefert wird.The controller 48 is also provided with a setpoint generator 49 connected, which is a target value Fs of the feed force delivers to the controller 48. This setpoint Fs the Feed force varies depending on the angle of rotation α of the bending template 10, the position transmitter 30th is delivered.

Fig. 3 zeigt das Regelschema. Der Sollwert-Generator 49 enthält mehrere Kurven, die den Sollwert Fs der Vorschubkraft in Abhängigkeit vom Drehwinkel α der Biegeschablone 10 angeben. An dem Sollwert-Generator kann die jeweils gewünschte Kurve ausgewählt werden. Ferner kann an dem Sollwert-Generator der Wert α für den Start und das Ende der Rohrbearbeitung eingegeben werden. Der Sollwert-Generator 49 liefert dann in Abhängigkeit von α den jeweils zugehörigen Sollwert Fs, von dem in einem Subtrahierer 50 der Istwert Fi subtrahiert wird. Das Subtraktionsergebnis wird dem Regler 48 zugeführt, der beispielsweise ein PID-Regler ist. Dieser Regler liefert über die Steuerleitung 39 ein Regelsignal an die Regelstrecke 51, die hier aus dem Differentialventil 42 und dem Zylinder 22 (Fig. 2) besteht.Fig. 3 shows the control scheme. The setpoint generator 49 contains several curves representing the setpoint Fs of the feed force depending on the angle of rotation α of the bending template Specify 10. Can on the setpoint generator the desired curve can be selected. Further can the value α for the start on the setpoint generator and the end of pipe machining can be entered. The Setpoint generator 49 then delivers depending on α the associated setpoint Fs, of which in a Subtractor 50 the actual value Fi is subtracted. The Subtraction result is fed to the controller 48 which for example a PID controller. This controller delivers via the control line 39 a control signal to the Control path 51, which here consists of differential valve 42 and the cylinder 22 (Fig. 2).

Der Druck P1 in der Leitung 40 und der Druck P2 in der Leitung 41 werden dem jeweiligen Wandler 46 bzw. 47 zugeführt. Das Ausgangssignal des Wandlers 46 wird in einem Multiplizierer 52 mit einem Wert multipliziert, der der Fläche A1 des Kolbens 23 entspricht. Das Ausgangssignal des Wandlers 47 wird in einem Multiplizierer 53 mit einem Wert multipliziert, der der Größe der Fläche A2 des Kolbens 23 entspricht. Der Multiplizierer 52 bildet also das Produkt P1 x A1 und der Multiplizierer 53 bildet das Produkt P2 x A2. Jedes dieser Produkte ist ein Maß für eine der beiden Kräfte, die gegensinnig zueinander auf den Kolben 23 einwirken. Ein Subtrahierer 54 subtrahiert die beiden Produkte voneinander, so daß der Istwert Fi der Vorschubkraft entsteht. Dieser Istwert wird in dem Subtrahierer 50 von dem Sollwert Fs subtrahiert, um das Eingangssignal für den Regler 48 zu bilden.The pressure P1 in the line 40 and the pressure P2 in the Line 41 are the respective converter 46 and 47th fed. The output signal of converter 46 is shown in a multiplier 52 multiplied by a value, which corresponds to the area A1 of the piston 23. The output signal of the converter 47 is in a multiplier 53 multiplied by a value equal to the size of the Surface A2 of the piston 23 corresponds. The multiplier 52 thus forms the product P1 x A1 and the multiplier 53 forms the product P2 x A2. Any of these products is a measure of one of the two opposing forces interact with each other on the piston 23. A subtractor 54 subtracts the two products from each other, so that the actual value Fi of the feed force arises. This actual value is in the subtractor 50 from the Setpoint Fs subtracted to the input signal for the Form controller 48.

Die Ausgangssignale der beiden Wandler 46 und 47 werden einer Fehlerauswertung 55 zugeführt, die ein Alarmsignal erzeugt oder die Rohrbiegemaschine stillsetzt, wenn die Drücke P1 und P2 Abnormalitäten zeigen. Es können auch z.B. Totalausfälle des Sensors aufgezeigt werden.The output signals of the two converters 46 and 47 are an error evaluation 55 fed an alarm signal generated or stops the pipe bending machine if the pressures P1 and P2 show abnormalities. It can also e.g. Total failures of the sensor are shown.

Claims (6)

  1. A method for controlling a pipe bending machine comprising a rotatable bending template (10), a clamping jaw (15) pressing the pipe (13) against the bending template (10), and a slide rail (32) engaging the unbent pipe section (13a) and being adapted to be advanced by a hydraulic cylinder (22), the slide rail transmitting a feed force on the pipe, wherein
       the respective bending angle (α) of the bending template (10) is measured,
    characterized in that
    a set value (Fs) for the advance force, corresponding to the bending angle (α), is outputted from a set value generator (49),
    the actual value (Fi) of the advance force is determined,
    and the pressures (P1,P2) in the cylinder (22) are varied such that the actual value (Fi) follows the set value (Fs) of the advance force.
  2. The method according to claim 1, wherein the actual value (Fi) of the advance force is determined by detecting the pressures (P1,P2) in the cylinder (22) on both sides of the piston (23) and determining the actual value (Fi) of the advance force from the pressures, taking into account the sizes of the two piston surfaces (A1,A2).
  3. The method according to claim 1 or 2, wherein the pressures (P1,P2) in the cylinder (22) on both sides of the piston (23) are varied contrary to one another.
  4. A pipe bending machine for bending a pipe (13), comprising a bending template (10) rotatable by a drive (33), a clamping jaw (15) pressing the pipe (13) against the bending template (10), a slide rail (32) engaging the unbent pipe section (13a) and being driven by a hydraulic cylinder (22), a position sensor (30) for detecting the rotational position of the bending template (10), and a means influencing the pressure in the cylinder (22) for the advance of the slide rail (32) in dependence on the signal of the position sensor (30),
    characterized in
    that a means (46,47,52,53) for determining the actual value (Fi) of the advance force (F) applied by the cylinder (22) is provided, and wherein a controller (48) adjusts the actual value (Fi) of the advance force in correspondence to a set value (Fs) generated by a set value generator (49) in dependence on the bending angle (α) supplied by the position sensor (30).
  5. The pipe bending machine according to claim 4, wherein the means (46,47,52,53) for determining the actual value (Fi) of the advance force (F) comprises two pressure sensors (46,47) detecting the pressures (P1,P2) on both sides of the piston (23).
  6. The pipe bending machine according to claim 4 or 5, wherein the controller (48) controls a control valve (42) having a continuous throttle characteristic and varying the pressures (P1,P2) on both sides of the piston (23) contrary to one another.
EP96109222A 1995-06-17 1996-06-08 Method for controlling a tube bending machine Expired - Lifetime EP0748662B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19522062 1995-06-17
DE19522062A DE19522062A1 (en) 1995-06-17 1995-06-17 Method for controlling a pipe bending machine

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EP0748662A1 EP0748662A1 (en) 1996-12-18
EP0748662B1 true EP0748662B1 (en) 2000-03-22

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Publication number Priority date Publication date Assignee Title
US5836188A (en) * 1997-04-09 1998-11-17 Pilot Industries, Inc. Method and apparatus for bending an elongated member to a target angle
US5907896A (en) * 1997-09-10 1999-06-01 Tseng; Shao-Chien Method for bending forging artistic metallic pipes
US6014884A (en) * 1997-12-11 2000-01-18 Proprietary Technology, Inc. Method of bending tubing
US6253595B1 (en) * 1999-09-21 2001-07-03 Crc-Evans Pipeline International, Inc. Automated pipe bending machine
US7765841B2 (en) * 2006-02-16 2010-08-03 Oes, Inc. Quality analysis of tube bending processes including mandrel fault detection
US7302823B1 (en) * 2006-07-06 2007-12-04 Crc-Evans Pipeline International, Inc. Gauge for pipe bending machine
CN102773319A (en) * 2012-08-07 2012-11-14 张家港市华舜机械制造有限公司 Auxiliary push device of pipe bender
CN106040807B (en) * 2016-08-10 2017-12-15 上虞市荣迪机械有限公司 Copper pipe bending machine

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US3303683A (en) * 1963-11-27 1967-02-14 Pines Engineering Co Inc Press die assembly for bending machines
DE2304838C2 (en) * 1973-02-01 1982-08-19 Deutsche Babcock Ag, 4200 Oberhausen Pipe bending device
US4201073A (en) * 1978-03-17 1980-05-06 Eaton-Leonard Corporation Reaction bender for pipe
JPS58205620A (en) * 1982-05-26 1983-11-30 Hitachi Ltd Pipe bending device
US4747283A (en) * 1987-08-24 1988-05-31 Teledyne Industries Boosted drive for pressure die of a tube bender
US4970885A (en) * 1989-06-12 1990-11-20 Vickers, Incorporated Tube bending apparatus
DE4129478A1 (en) * 1991-09-05 1993-03-11 Schwarze Rigobert METHOD FOR CONTROLLING A PIPE BENDING MACHINE
US5343725A (en) * 1993-07-07 1994-09-06 Eagle Precision Technologies Inc. Tube bending apparatus and method

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DE19522062A1 (en) 1996-12-19
DE59604728D1 (en) 2000-04-27
EP0748662A1 (en) 1996-12-18
CA2178985C (en) 2006-10-03
CA2178985A1 (en) 1996-12-18
US5682781A (en) 1997-11-04

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