EP2686161B1 - Drawing press having two couplable rams - Google Patents

Description

The invention relates to a drawing press, which is used for the production of Umformblechteilen, such as Karoserieteilen.

For deep drawing sheet metal parts double acting presses are known. In such presses, a sheet-metal retaining ring is arranged relatively movable to a drawing punch. The sheet holding ring is applied to the board to be reshaped and exerts a holding force or clamping force, while the drawing punch then forms the board in cooperation with a mold. Such a press is for example from the DE 24 19 389 known. There, a hydraulic drawing press is provided, in which both a drawing punch, as well as a sheet-metal retaining ring 12 are attached to a movable in the direction of the ram. During the downward movement of the plunger, therefore, first of all the sheet-metal retaining ring on the board strikes and only with continued downward movement is a forming of the board by the drawing punch.

DE 24 19 389 A1 describes a drawing press with a first plunger which is movably supported by a first plunger drive in a working direction in a press frame, and with a second plunger, which is mounted by a second plunger drive in the working direction movable in a press frame.

Out DE 199 43 441 A1 Furthermore, a double-acting forming machine with an inner tappet and an outer tappet is known. An eccentric drive has an eccentric shaft, which is connected via connecting rods with the outer tappet. One Toggle lever drive with two articulated levers connects the inner tappet via a further lever with the eccentric shaft.

Starting from the known presses, it can be regarded as an object of the present invention to make the possible applications of the press more flexible and to ensure a high quality of the formed parts produced. This object is achieved by a drawing press according to claim 1.

The drawing press has a first plunger, which can be driven by a first plunger drive in one working direction. Furthermore, the drawing press has a second plunger, which is drivable by means of a second plunger drive. The two plunger drives each have an electric motor. Both plunger drives can be activated independently of each other, so that the movements of the first plunger and the second plunger relative to the lower tool or to the board are independently feasible and specifiable. To control the plunger drives is a control unit. The drawing press also has a coupling means, which is switchable between a coupling state and a decoupling state. In the coupling state, a kinematic coupling is produced between the two tappets, which prevents a relative movement of the first tappet relative to the second tappet. Preferably, the coupling means is a mechanical coupling means, which in one embodiment produces a direct mechanical connection between the two tappets and, in another embodiment, effects a kinematic coupling of the two tappet drives. About the coupling means, the drawing press is therefore switchable between a single-acting mode in the coupling state and a double-acting mode in the decoupling state.

In the decoupling state, the second plunger can be used for example as a hold-down. Its position, its movement speed and / or its clamping force, with which it holds the board, is freely definable and independent of the position and / or the speed with which the first plunger moves, which can serve as a drawing punch, for example. The sheet holding force, which is exerted by the second plunger in this mode and their course during the drawing process are decisive for the quality of the produced Umformteils. Due to the independence of the two plunger movements, the sheet-holding force exerted by the second plunger on the board can be adapted to the requirements of the drawing operation, such as drawing. the material and the thickness of the board are adjusted. It is also possible to set this sheet holding force completely independent of the current position of the drawing punch formed by the first plunger. In this way, the sheet holding force can be adjusted, for example, to the speed of the first drawing punch. Regardless of the movement control of the first drawing punch also results in the ability to provide via the control unit switching between a position-controlled or position-controlled and a force-controlled or force-controlled control of the second ram drive.

If the coupling state is established via the coupling means, the two plungers move together in the working direction. This makes it possible to press the two plungers against the board with a large forming force. The forces provided in the working direction by the first ram drive and the second ram drive can be added in the coupling state to a high total force. Depending on the specific machining task, it may also be sufficient in the coupling state, if only one of the plunger drives is moved. The two plungers preferably form a common enlarged clamping surface in the coupling state. In the coupling state, the drawing press works as a single-acting press together with a drawing tool, which is mounted in this mode of operation on the press frame.

It is advantageous if the two plunger drives are kinematically identical. They can be designed, for example, as eccentric drives or joint drives. Due to the identical design of the two plunger drives is achieved that in the case of coupling by the control unit can easily be the same control of both plunger drives, if the pulling force required for the drawing process is greater than the force that can be applied by a single plunger drive. A complex control with different specifications for each ram drive is avoided in this case.

The coupling means can for example produce a kinematic connection between the two plunger drives. In this case, it can be configured as a switchable shaft coupling or as an intermediate gear between the two plunger drives. In particular, the coupling means is driven by the control unit to switch between the coupling state and the decoupling state. The operating state of the drawing press can be changed very quickly and easily in this way.

The electric motors of the plunger drives can be designed as servomotors or torque motors. These allow precise adjustment of the position and / or force of the plunger in the working direction. The ram drives are, so to speak, "dry" and require no hydraulic fluid. The two ram drives are in the preferred embodiment the drawing press designed as top drives and therefore arranged above the two plunger on the press frame. The ram in the direction opposite lower tool can be performed completely unpowered.

• Figur 1 eine schematische, blockschaltbildähnliche Seitenansicht eines Ausführungsbeispiels einer Ziehpresse im Entkopplungszustand,
• Figur 2 das Ausführungsbeispiel der Ziehpresse gemäß Figur 1 in gleicher Ansicht im Kopplungszustand,
• Figur 3 ein Blockschaltbild eines Ausführungsbeispiels eines Kopplungsmittels zur Kopplung der Stößelbewegung,
• Figur 4 ein Blockschaltbild eines anderen Ausführungsbeispiels eines Kopplungsmittels zur Kopplung der Stößelbewegung und
• Figur 5 eine schematische blockschaltbildähnliche Darstellung der Stößelantriebe in einer Ausgestaltung als Gelenkantriebe.

Advantageous embodiments of the drawing press according to the invention will become apparent from the dependent claims and the description. The description relates to advantageous embodiments of the drawing press according to the present invention. The drawing is to be used as a supplement. Show it:

• FIG. 1 FIG. 2 is a schematic, block diagram similar side view of an embodiment of a drawing press in the decoupling state,
• FIG. 2 the embodiment of the drawing press according to FIG. 1 in the same view in the coupling state,
• FIG. 3 a block diagram of an embodiment of a coupling means for coupling the plunger movement,
• FIG. 4 a block diagram of another embodiment of a coupling means for coupling the plunger movement and
• FIG. 5 a schematic block diagram similar representation of the plunger drives in one embodiment as a joint drives.

In the FIGS. 1 and 2 a drawing press 10 is shown, which has a press frame 11, which has a plurality of substantially vertically extending stand 12, which carry a head 13. The lower part of the press frame 11 includes a base 14 to which the supports 12 are connected. The base 14, the stand 12 and the head 13 form a closed, rigid frame.

On the press frame 11, a first plunger 17 and a second plunger 18 are arranged in a working direction A and, for example, substantially vertically movable. In the embodiment described here, the first plunger 17 is designed as an inner plunger, which is surrounded by the second plunger 18 annular. The two plungers 17, 18 are arranged coaxially with each other. On the first plunger 17, an upper tool part 19 is arranged, for example, which cooperates with a lower tool part 20 of a lower tool 21 for forming a circuit board 22.

To drive the first plunger 17, a first plunger drive 25 is present. The first plunger drive 25 has a first electric motor 26, for example a servomotor or a torque motor, which drives a first eccentric shaft 27. At least one eccentric 28 and, according to the example, two eccentrics 28 are arranged on the first eccentric shaft, on each of which rotatably a connecting rod 29 is mounted. Each connecting rod 29 is pivotally connected to the eccentric 28 side with the first plunger 17. Upon rotation of the eccentric shaft 27, the connecting rods 29 are displaced in the working direction A, whereby the up and down movement of the first plunger 17 in the working direction A can be caused.

A second ram drive 30 with a second Electric motor 31 serves to drive the second plunger 18. The two plunger drives are constructed kinematically identical. The second electric motor 31 thus drives a second eccentric shaft 32, on which at least one and, for example, two eccentrics 28 are arranged in a rotationally fixed manner. On this eccentric 28, 25 two connecting rods 29 are rotatably mounted analogously to the first eccentric, which are pivotally connected to the second plunger 28. The two plunger drives 25, 30 are constructed kinematically identical. They have the same electric motors 26, 31 and equal ratios, so that when driving the plunger drives 25, 30 with the same control variable, the same movement of the respective associated plunger 17, 18 is caused in the working direction A. The connecting rods 29 of the plunger drives 25, 30 are the same length. With the same control variable of the two plunger drives 25, 30, substantially equal forces of the plungers 17 and 18 in the working direction A result.

The two plunger drives 25, 30 are controlled by a control unit 33. The control unit 33 can independently set and specify the movement and / or position and / or force of each plunger 17, 18. In this way, the first plunger 17 and / or the second plunger 18, for example, position-controlled or position-controlled or force-controlled or force-controlled. The corresponding control of the plunger drive 25, 30 and the respective electric motor 26, 31 is carried out by the control unit 33rd

In addition, via the control unit 33, a coupling means 35 will be switched between a coupling state and a decoupling state. In the decoupling state, the two plungers 17, 18 can move completely independently of one another in the working direction A. In the coupling state, the coupling means 35 prevents a Relative movement between the two plungers 17, 18 in the working direction A. In the latter case, the two plungers 17, 18 move exclusively together.

In the exemplary embodiments described here, the coupling means 35 produces a mechanical and / or kinematic coupling between the two tappets 17, 18. In a first embodiment according to FIG. 3 For this purpose, the two plunger drives 25, 30 are kinematically coupled. For example, it is possible, the two eccentric shafts 27, 32 of the two plunger drives 25, 30 rotatably connected by a shaft coupling 36 in the coupling state with each other. The shaft coupling 36 is designed switchable and separates the two eccentric shafts 27, 32 in the decoupling state from each other. The shaft coupling 36 can be switched by the control unit 33. As an alternative to this preferred embodiment, it is also possible for the shaft coupling 36 or another coupling means 35 to be made mechanically switchable by an operator, so that a manual switching between the coupling state and the decoupling state takes place.

In FIG. 4 an alternative embodiment of the coupling means 35 is shown. There, a mechanical connection is made by the coupling means 35 directly between the first plunger 17 and the second plunger 18, when this is in the coupling state. In the decoupling state, the coupling means 35 releases the relative movement between the two plungers 17, 18. The mechanical connection in the coupling state can be achieved for example by a frictional and / or positive connection between the two plungers 17, 18, for example by latching means and / or clamping means. The coupling means 35 can also at this embodiment as shown schematically in FIG. 4 represented by the control unit 33 can be switched over or, alternatively, manually switched over.

The drawing press 10 can be operated depending on the state of the coupling means 35 either as a double-acting press or as a single-acting press. For operation as a single-acting press, the lower tool 21 has a pulling device 40 (FIG. FIG. 2 ). The drawing device 40 has, for example, a table cushion 41 with a floating plate 42, which can be positioned and / or moved in the working direction A of the drawing press 10 via a table cushion drive 43. On the floating plate 42 a plurality of push rods 46 are arranged, which pass through a press table 44 and at its the upper tool part 19 and the plungers 17, 18 facing the end of an annular plate holder 45 have. On the press table 44 below the plate holder 45, the lower tool part 20 is arranged.

The upper tool part 19 and the lower tool part 20 are complementary to each other. It is both possible to design the lower tool part 20 or the upper tool part 19 as a mold with a concave recess, as shown by way of example in FIGS FIGS. 1 and 2 is shown.

• Mit Bezug auf Figur 1 wird der Betrieb der Ziehpresse 10 im Entkopplungszustand des Kopplungsmittels 35 erläutert. Die Ziehpresse arbeitet hier als doppelt wirkende Presse. Der zweite Stößel 18 dient in diesem Fall als Niederhalter. Vor dem Umformvorgang der Platine 22 wird zunächst der zweite Stößel 18 nach unten bewegt bis er an der Platine 22 anliegt. Die Bewegung bis zur Platine 22 in Arbeitsrichtung A erfolgt durch die Steuerung oder Regelung der Position des zweiten Stößels 18. Sobald er die Platine 22 erreicht hat, schaltet die Steuereinheit 33 auf die Steuerung oder Regelung der Klemmkraft um, die der zweite Stößel 18 auf die Platine 22 ausübt. Diese wird zwischen dem zweiten Stößel 18 und einer am Unterwerkzeug 21 vorhandenen Klemmfläche gehalten.

The drawing press 10 works as follows:

• Regarding FIG. 1 the operation of the drawing press 10 in the decoupling state of the coupling means 35 will be explained. The drawing press works here as a double-acting press. The second plunger 18 serves as a hold-down in this case. Before the forming process of the board 22, the second plunger 18 is first moved down until it to the board 22 is applied. The movement up to the board 22 in the working direction A is carried out by the control or regulation of the position of the second plunger 18. Once he has reached the board 22, the control unit 33 switches to the control or regulation of the clamping force, the second plunger 18 on the Board 22 exerts. This is held between the second plunger 18 and an existing on the lower tool 21 clamping surface.

The control unit controls the second ram drive 30 independently of the first ram output 25 so that it only reaches the board 22 when the first ram 18 acts on the board 22 with the desired clamping force. About the control or regulation of the position and / or the speed of the first plunger 17 in the working direction A, the actual drawing process of the board 22 is performed. For this purpose, the upper tool part 19 and the lower tool part 20 work together and bring the board 22 in the desired shape. During this forming operation, the clamping force that the second plunger 18 exerts on the board 22 may vary. The clamping force can be adjusted according to the position and / or the speed of the first plunger 17. Because of the independence of the two plunger drives 25, 30 and because the plunger drives 25, 30 are designed as electrical drives, a corresponding control by the control unit 33 is very simple and accurate.

The drawing press 10 can also be operated as a single-acting press, as in FIG. 2 is shown. In this embodiment, the drawing tool 40 is additionally attached to the lower tool 21. In the operation of the drawing press 10 as a single-acting press the sheet holding ring 45 and the push rods 46 are connected to the floating plate 42. Should the operating mode be double acting press are set, the push rods 46 and the sheet holder ring 45 can be easily removed. The operating state as a single-acting press is further adjusted by the coupling means 35 is switched to its coupling state. In this case, the two plungers 17, 18 are coupled for movement. They form on their side facing the lower tool 21 side a common clamping surface 50. The moments of the two electric motors 26, 31 of the two plunger drives 25, 30 can be added in this state, so that the force with which the two plungers 17, 18 together against the board 22 can be moved may be greater than the force that can be applied by the first or second ram drive 25, 30 alone. As a result, forming processes with the drawing press 10 are feasible, requiring a large force of the plunger 17, 18 in the working direction A and can not be produced in the operating state as a double-acting press. Due to the coupling of the two plungers 17, 18, these move simultaneously in the working direction A and at the same time hit the board 22, which rests on the plate holder 45. Against the force of the sheet holder, which is applied over the table cushion drive 43, the two plungers 17, 18 move the board 22 together with the blank holder 45, the push rods 46 and the floating plate 42 in the working direction A, wherein the upper tool part 19 and the lower tool part 20 cooperate and a transformation of the board 22 takes place.

In the embodiments described here, the two plunger drives 25, 30 are designed as upper drives. According to the embodiment according to FIG. 1 and 2 are the plunger drives 25, 30 formed by eccentric drives. In a modification of the illustrated embodiment, each plunger drive 25, 30 also more than one Electric motor 26, 31 have.

Instead of the eccentric drives 25, 30 can be used as a ram drive and a joint drive 51. A joint drive 51 has two levers 52 connected to one another in an articulated manner, the one lever 52 being connected to the associated plunger 17 or 18 and the other lever 52 being connected in an articulated manner to the press position 11. At the articulated connection between the two levers 52 sits a drive lever 53 which is driven by an eccentric 54.

The invention relates to a drawing press 10 with a first plunger 17 and a second plunger 18. The first plunger 17 is moved by an electromotive first plunger drive 25 and the second plunger 18 by an electromotive second plunger drive in a working direction A. The drawing press 10 further includes a coupling means 35 which is switchable between a decoupling state and a coupling state. In the decoupling state, the two plungers 17, 18 can move independently of one another in the working direction A. In the coupling state, the coupling means 35 ensures that a relative movement between the two plungers 17, 18 is prevented. The drawing press 10 can therefore be operated as a single or double-acting press.

LIST OF REFERENCE NUMBERS

10

drawing press

11

press frame

12

stand

13

head

14

base

17

first pestle

18

second stamp

19

upper tool part

20

lower tool part

21

lower tool

22

circuit board

25

first ram drive

26

first electric motor

27

first eccentric shaft

28

eccentric

29

pleuel

30

second ram drive

31

second electric motor

32

second eccentric shaft

35

coupling agent

36

shaft coupling

40

puller

41

table cushion

42

floating plate

43

Table cushion drive

44

press table

45

blankholder

46

pushrod

50

clamping

51

joint drive

52

lever

53

drive lever

54

eccentric

A

working direction

Claims (14)

1. Drawing press (10),
   with a first slide (17), which is mounted in a press frame (11) to be movable in a working direction (A) by a first slide drive (25),
   with a second slide (18), which is mounted in a press frame (11) to be movable in a working direction (A) by a second slide drive (30),
   characterised in that the two slide drives (25, 20) respectively have an electric motor (26, 31) and are capable of being driven independently of one another,
   that a control unit (33) is provided for actuation of the two slide drives (25, 20),
   and that a coupling element (35) is provided, which can be switched over between a decoupled state that permits independent slide movements and a coupled state that prevents a relative movement of the two slides (17, 18).
2. Drawing press according to claim 1, characterised in that the two slide drives () are kinematically identical.
3. Drawing press according to claim 1, characterised in that the two slide drives (25, 30) are configured as cam drives (28, 29) or articulation drives (51).
4. Drawing press according to claim 1, characterised in that in the coupled state the slides (17, 18) move together in the working direction (A) and cooperate with a drawing device (41).
5. Drawing press according to claim 1, characterised in that in the coupled state the coupling element (35) creates a mechanical connection directly between the first slide (17) and the second slide (18).
6. Drawing press according to claim 1, characterised in that in the coupled state the coupling element (35) creates a kinematic connection between the first slide drive (25) and the second slide drive (30).
7. Drawing press according to claim 1, characterised in that in the coupled state a driving force caused by a slide drive (25, 20) acts on both slides (17, 18).
8. Drawing press according to claim 1, characterised in that in the coupled state only one or both slide drives (25, 30) are operated in dependence on the required pressing force.
9. Drawing press according to claim 1, characterised in that in the coupled state the two slides (17, 18) form a common clamping surface (50).
10. Drawing press according to claim 1, characterised in that the second slide (18) surrounds the first slide (17) in a ring shape.
11. Drawing press according to claim 1, characterised in that the two slide drives (25, 30) are configured as top drives.
12. Drawing press according to claim 1, characterised in that in the decoupled state the second slide (18) serves as holding element.
13. Drawing press according to claim 1, characterised in that the control unit (33) is fitted to actuate the second slide drive (30) either for controlling the position or controlling the power of the second slide (17).
14. Drawing press according to claim 13, characterised in that the control unit (33) is fitted to actuate the second slide drive (30) in dependence on the speed and/or the position of the first slide (17).

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