EP1981663B1 - Method and deep-drawing device for the deep drawing of sheet metal - Google Patents

Abstract

A method and a deep-drawing apparatus for the deep drawing of a metal sheet by means of a press, a table, a drawing punch, and also a drawing die and a counterpressure plate interacting with the drawing die, which together form a flow path for the metal sheet, wherein at least one drawing strip movable relative to the counterpressure plate is pushed transversely through the flow path of the metal sheet in order to deflect the metal sheet during a drawing phase (first deflection phase) and the drawing strip, for a stop phase, is pushed by a further short distance transversely through the flow path (F) (second deflection stage), wherein a deflection increased once again inhibits the flow of the metal sheet during the second deflection stage, and wherein the metal sheet is essentially plastically formed at the end of the deep-drawing operation, wherein the degree of deflection required during the first deflection stage is set by means of an interchangeable distance piece which is arranged between the counterpressure plate and the drawing strip and serves as a limit stop. Independently thereof, the degree of deflection required during the second deflection stage can be set by further distance elements which are arranged between the table and the drawing strips.

Description

The invention relates to a method for deep drawing metal sheet by means of a press, a table, a drawing die, and a drawing die and cooperating with the drawing die counter-pressure plate, which together form a flow path for the metal sheet, wherein at least one relative to the platen movable drawing strip across the flow path of the metal sheet is pushed to redirect the metal sheet during a drawing phase - first deflection - and the pull bar for a stop phase is pushed another piece across the flow path - second deflection -, wherein during the second deflection a further increased deflection the flow of the metal sheet 8, and wherein the metal sheet is substantially plastically deformed at the end of the deep drawing operation.

The flow path is a drawing gap formed between the drawing die and the counterpressure plate. The metal sheet slips through this drawing gap, being inhibited by the pressure of the counter-pressure plate.

In addition, the invention relates to a deep-drawing device for metal sheets with a table, a drawing punch, a press, a drawing die, a counter-pressure plate, a plurality of pull strips, which are mounted parallel to the pressing direction with the press movable in the counter-pressure plate, and provided with at the edge of the draw die Ziehrillen, in which the drawbars are gradually hineinbewegbar while maintaining a drawing gap, wherein for the purpose of stepwise deformation of the metal sheet a drawing phase is provided, during which the metal sheet receives a draw bead with low bead depth and at least one stop phase is provided during the Metal sheet receives a stop bead, which has a greater bead depth than the draw bead.

Usually very large mechanical or hydraulic presses with counter-holding devices are used for the production of body parts, which must ensure an exact adjustability of the pressing and holding force substantially because different drawn parts require different pressing and holding forces. The counter-holding devices can be designed in various ways, preferably the counter-holding force is applied hydraulically or by spring force.

Press and retainer provide the forces needed for forming. Moreover, a deep drawing apparatus is needed which has individual forming tools, such as drawing dies and drawing dies, as well as individual means of controlling the flow of material.

A generic method for deep drawing metal sheets and a thermoforming device is from the US 6,276,185 B1 known. Here, the material flow is controlled with two pull strips, which are arranged symmetrically to a drawing punch. The pull strips are pushed transversely into the flow path of the metal sheet to meter the flow of material. This first deflection stage is maintained until the lower ends of the pull strips, which protrude freely from a counter-pressure plate, strike a table. From this point on the drawing strips are pushed further across the flow path of the metal sheet, whereby the flow process is further inhibited.

A disadvantage of this prior art is the lack of variability of the thermoforming device. The known thermoforming device can be retrofitted or adjusted only with great effort, if the adjustment of the adjustment is necessary.

Another thermoforming device is from the DE 199 53 751 A1 known. This proposes pull bars to be moved via mechanical transmissions or hydraulic circuits, but it is not intended to push the pull bars for a pull phase and a stop phase in two steps across the flow path. The from the DE 199 53 751 A1 Known measures to drive the pull strips are complicated and prone to damage and therefore appear especially for mass production, as z. B. present in the automotive industry, little suitable.

The invention is therefore based on the object to provide a method for deep drawing of metal sheets, which ensures an exact repeatable deflection of the flow path of the metal sheet during a drawing phase, with a simple and quick adjustability value is set to vary the degree of deflection, if a fine adjustment z. B. during wear of the tool or when changing the material properties is necessary.

According to the invention the object is achieved by a generic method in which the required during the first deflection level degree of deflection is adjusted by means of an exchangeable spacer which is disposed between the platen and the pull bar and serves as a stop.

Pulling strips are usually arranged in sections around a metal sheet around and form a kind of frame that controls the pulling movement of the metal sheet. According to the new method, the extent to which the pull bar protrudes into the flow path of the metal sheet, set by a fixed stop. Since the spacer is very easily replaceable, that spacer can be changed if a different level is required by which the pull bar must traverse the flow path of the metal sheet.

Thus, in a simple manner, the commercial fluctuation of the material characteristics of thermoforming sheets or the deliberate change in the Material characteristics are compensated. With the invention, a fine adjustment of the deep-drawing tool even when pressing a batch, usually a steel roll (coil), are performed, since the time required is low and thus the production downtime is limited. But even if a readjustment is necessary because z. B. another deep-drawn part made of a different material in the same thermoforming tool to be produced, for. B. from another, firmer or softer steel grade, the conversion of the thermoforming tool can be done quickly and easily. This plays a role in the platform strategy in automotive companies, where different vehicles are built on the same platform, ie the shape of the corresponding deep-drawn parts is the same, while the strength adjustment of the deep-drawn parts to the respective vehicle on the selection of different materials, in particular here to name the most diverse high-strength steels.

The pull bar according to the invention may be a one-piece or a multi-part pull bar, wherein the multi-part pull bar has a carrier and at least one drawing tool, which is exchangeably received in the carrier.

Advantageously, the pull bar is detachably mounted in the counter-pressure plate. It can be quickly removed in this way to replace the spacer arranged underneath. To ensure the desired variability, spacers are provided with different distance measure, which can be used optionally. With each spacer an individual measure of the deflection of the metal sheet is achieved.

A development of the method provides that a pressure pin is provided between the table and pull bar, that the pressure pin is shorter than the distance between the table and pull bar during the drawing phase of each other, wherein the distance is reduced during the drawing phase and at the end of the drawing phase or Beginning of the stop phase of the pressure pin is clamped between the table and pull bar, whereby the pressure pin a compressive force in the moves movable pull bar and the pull bar is lifted from serving as a stop for the pull bar spacer, whereby the pull bar is moved to the second deflection.

During the displacement of the drawing strip from the first to the second deflection stage, the flow of the metal sheet in the flow path is delayed. The second deflection stage can cause an inhibition of the drawing process, which is so great that the metal sheet is stopped by the deflection and is transformed only plastically by continuing the deep drawing process.

Whether the second deflection phase starts sooner or later depends on the extension of the pressure bolt by the spacers. A long pushpin is more likely to get caught between the table and the pull bar than a short pushpin. In this way, it can be set how long the drawing phase lasts and when the stopping phase begins, wherein the relative movement of the pressure pin always begins at the same time.

The end of the movement of the pull bar, synonymous with the second deflection, is reached when the counter-pressure plate has come into frictional contact with the table. This can be done by direct or indirect contact.

The proposed method uses a pull bar, which can be variably used by combination with different spacers to individually tune the degree of deflection of the metal sheet during the drawing phase. In this way, different bead depths can be achieved without using a separate drive that would have to control the bead depth.

The drive for the movement of the drawing strips from the first to the second deflection takes place by adhesion between the table, pressure pin and pull bar.

From then on, the stop phase begins, during which the pull bar is pushed further through the flow path of the metal sheet.

To solve the problem, a generic deep-drawing device is further proposed, wherein according to the invention for the purpose of setting the bead depth of the pulling bead acting during the draw phase at least one replaceable spacer is provided, and that the spacer between the platen and the pull bar acts.

Since a pull bar may be a long tool, several spacers can be arranged side by side, which support the pull bar evenly. In this way, a bending of the pull bar is avoided.

The proposed thermoforming device is further designed to allow a rapid conversion for the purpose of producing different drawn parts, the depth of which must be adjusted individually. It is important to arrange the distance to be exchanged for adjustment easily accessible between the removable pull bar and the counter-pressure plate.

In addition, the inventive solution emphasizes the robustness of the device. The proposed way of controlling the movement of the pull bar is very low maintenance and easy to use and compared to that from the DE 199 53 751 A1 known fault-prone Ziehleistensteuerung particularly reliable.

Advantageously offset to the spacer between the drawing strip and the table, a pressure pin is arranged and is with the pressure pin a compressive force between the table and the pull bar transferable. The pushpin is easily removable after removal of the pull bar for conversion to another drawn part to be produced. He can be replaced with a pressure pin, which has a different length.

Suitably, the thermoforming device is designed so that the pressure pin is clamped during the stop phase between the table and pull bar and pressure-free during the drawing phase, because the distance between the table and pull bar during the drawing phase is greater than the length of the pressure bolt. With the inventive combination of spacer and pressure pin, the total path that the drawing die is pressed onto the punch can be variably divided into a drawing phase and a stopping phase.

The handling of the thermoforming device can be further improved if at least one spacer element is provided, which is arranged in addition to the pressure pin between the table and the drawing strip. The spacer element is connected in series with the table, the pressure pin and the drawing strip, and is desirably arranged so that it is easily accessible and replaceable without much effort. In this way, if the stop phase is to be changed, to dispense with an exchange of the pressure bolt. Alternatively, the spacer is replaced to vary the stop phase.

The spacer element may be a spacer with a fixed distance measure. In this case, individual spacers are provided with different distance measure for different drawn parts made of different materials. Alternatively, an adjustable distance device may be provided, which does not need to be replaced, because the Distanzmaß the distance device is variable. As distance device, an eccentric may be provided or a few spacer wedges, which allow by shifting against each other a variable distance dimension of the spacer device.

The pressure pin is simply axially movably mounted in the counter-pressure plate, namely movable parallel to the pressing direction of the press.

One embodiment of a pressure pin has at the end facing the pull bar on a radially projecting retaining collar whose diameter is larger as a bearing bore of the counter-pressure plate, in which the pressure pin is straight. In this way, the pressure pin is suspended in the counter-pressure plate. The pressure pin can be moved from this position in the counter-pressure plate in the direction of the pull bar. This happens when the lower end of the pressure pin strikes the table, namely a direct or indirect adhesion to the table is formed.

A further improvement provides that at least one spacer element between the table and the pull bar is arranged at both ends of the pressure bolt.

Through several spacer elements, which can be set together with the pressure pin between pull bar and table on block, the variability increases. For example, spacers that are stepped in increments of 1 mm can be combined with other spacers that have stepped spacers in increments of 0.5 mm. Of course, the grading of spacers may also be much finer than steps of 0.5 mm and substantially coarser than steps of 1 mm.

• Figur 1 eine Symmetriehälfte einer Tiefziehvorrichtung im Schnitt im geöffneten Zustand,
• Figur 2 die Tiefziehvorrichtung gemäß Fig. 1 während einer Ziehphase mit quer durch den Fließweg eines Metallblechs geschobene Ziehleiste,
• Figur 3 die Tiefziehvorrichtung gemäß Fig. 1 während einer Stoppphase am Ende des Tiefziehvorgangs,
• Figur 4 eine vergrößerte Darstellung einer Tiefziehvorrichtung mit einem direkt zwischen einer Ziehleiste und einem Tisch angeordneten Druckbolzen, das ganze als vergrößerter Ausschnitt,
• Figur 5 eine Seitenansicht der Tiefziehvorrichtung gemäß Fig. 4,
• Figur 6 die Tiefziehvorrichtung gemäß Fig. 4 während einer Stoppphase am Ende des Tiefziehvorgangs mit einem zwischen Ziehleiste und Tisch eingeklemmten Druckbolzen,
• Figur 7 eine Seitenansicht der Tiefziehvorrichtung in der Position gemäß Fig. 6,
• Figur 8 ein vergrößerter Ausschnitt einer alternativen Ausführungsform einer Tiefziehvorrichtung im Stadium einer Ziehphase gemäß Fig. 2,
• Figur 9 eine Seitenansicht der Tiefziehvorrichtung gemäß Fig. 8,
• Figur 10 eine ausschnittsweise Schnittdarstellung der Tiefziehvorrichtung gemäß der Fig. 8 und 9 im Stadium einer Stoppphase am Ende des Tiefziehvorgangs,
• Figur 11 eine Seitenansicht der Tiefziehvorrichtung gemäß Fig. 10,
• Figur 12 einen ausschnittsweisen Querschnitt durch eine Tiefziehvorrichtung mit einem von außerhalb des Werkzeuges einstellbaren Distanzelement in Reihe geschaltet mit einem Druckbolzen,
• Figur 13 eine Tiefziehvorrichtung mit einer Weiterbildung des Distanzelements gemäß Fig. 12,
• Fig. 14 einen ausschnittsweisen Querschnitt einer Tiefziehvorrichtung mit einem mit Druckbolzen in Reihe geschalteten einstellbaren Distanzelement, das einen Exzenter.

The invention is illustrated by way of example in a drawing and described in detail with reference to several schematic figures. Show it:

• FIG. 1 a symmetry half of a thermoforming device in section in the open state,
• FIG. 2 the thermoforming device according to Fig. 1 during a drawing phase with a pull bar pushed transversely through the flow path of a metal sheet,
• FIG. 3 the thermoforming device according to Fig. 1 during a stop phase at the end of the deep-drawing process,
• FIG. 4 an enlarged view of a thermoforming device with a directly between a pull bar and a table arranged pressure pin, the whole as an enlarged section,
• FIG. 5 a side view of the thermoforming device according to Fig. 4 .
• FIG. 6 the thermoforming device according to Fig. 4 during a stop phase at the end of the deep-drawing process with a pressure pin clamped between the pull bar and the table,
• FIG. 7 a side view of the thermoforming device in the position according to Fig. 6 .
• FIG. 8 an enlarged section of an alternative embodiment of a thermoforming device in the stage of a drawing phase according to Fig. 2 .
• FIG. 9 a side view of the thermoforming device according to Fig. 8 .
• FIG. 10 a partial sectional view of the thermoforming device according to the Fig. 8 and 9 in the stage of a stop phase at the end of the deep-drawing process,
• FIG. 11 a side view of the thermoforming device according to Fig. 10 .
• FIG. 12 a fragmentary cross-section through a thermoforming device with an adjustable distance from outside of the tool spacer in series with a pressure pin,
• FIG. 13 a deep drawing device according to a further development of the spacer element Fig. 12 .
• Fig. 14 a fragmentary cross section of a thermoforming device with a pressure pin in series adjustable spacer element, which has an eccentric.

In the FIGS. 1 to 3 a deep drawing process is shown in several steps. The sectional views each show a symmetry half of a thermoforming device 1. The thermoforming device 1 has a table 2. On the table 2 is a drawing punch 3, in addition to the drawing punch 3, a counter-pressure plate 4 is provided on the table 2, which directed away from the table can produce a counter-holding force. About the drawing punch 3 and the counter-pressure plate 4, the thermoforming device on a drawing die 5. The drawing die 5 is arranged on a press 6, with which a pressure in the direction of the table 2 is effected. In the counter-pressure plate 4, a pull bar 7 is arranged, which is movable transversely to the plane of a metal sheet 8 or transverse to a flow path F of the metal sheet 8 during the deep drawing operation. The flow path F is the path that, as in Fig. 2 shown between the drawing die 5 and the counter-pressure plate 4, orthogonal to the longitudinal extent of the pull bar towards the punch runs. The metal sheet 8 slips through this drawing as a flow path F drawing gap.

In Fig. 1 the thermoforming device 1 is shown in the open state. The drawing die 5 is arranged at a distance above the drawing die 3 and the counterpressure plate 4, so that a metal sheet 8 can be inserted into the deep drawing apparatus 1. The metal sheet 8 is initially only on the pull bar 7. The pull bar 7 projects to a certain extent from the counter-pressure plate 4. This measure is individually adjustable.

In Fig. 2 a drawing phase of the deformation is shown, during which the metal sheet 8 is pulled through the flow path F, which has formed between the drawing die 5 and the counter-pressure plate 4. For the deformation of the metal sheet 8, the drawing die 5 is moved by the force of the press 6 in the direction of the table 2. The Counterpressure plate 4 is pressed in the direction of the drawing die 5 and transmits a holding force in the metal sheet 8. It approach the drawing die 5 and the counter-pressure plate 4 in synchronous movement to the table 2, while the metal sheet 8 is clamped.

The pull bar 7 protrudes into a draw groove 9 provided in the draw die 5 and in this way effects a deflection of the flow path F of the metal sheet 8 Fig. 2 shown deflection of the metal sheet 8 through the pull bar 7 is bead-shaped and should be referred to as a draw bead 10 in the context of the invention. The bead depth of the draw bead 10 or in other words the amount of deflection remains constant during a drawing phase. The metal sheet 8 is pulled continuously through the draw bead 10. The end of the metal sheet, 8 moves closer and closer to the pull bar 7 zoom. The counter-pressure plate 4 and the drawing die 5 are approaching more and more the table 2. The thermoforming device 1 is constructed so that when lowering the counter-pressure plate 4, first a pressure pin 11 comes into contact with the table 2 and then with the pull bar 7. From this point, the drawing strip 7 is pushed deeper into the drawing groove 9 of the drawing die 5 to continue the thermoforming process, because the pressure pin 11 is clamped between the table 2 and pull bar 7. In other words, the pull bar 7 was lowered synchronously with the counterpressure plate 4 and the drawing die 5 during the drawing phase. The bead depth of the draw bead 10 remains constant. Once the pressure pin 11 has come into contact with the table 2 and the pull bar 7, the pull bar 7 can not be lowered further. If the drawing die 5 and the counter-pressure plate 4 are still lowered further, the depth of the bead increases and a bead is formed, which in the sense of the invention should be referred to as a stop bead 12. The deep-drawing process is completed at the latest when the drawing punch 3 with metal sheet 8 and drawing die 5 is positively or the counter-pressure plate 4 comes into contact with the table 2. For the two in Fig. 2 The distance D of the pressure bolt 11 to the table 2 is less than the distance G of the counter-pressure plate 4 to the table 2.

The end of the stop phase and the end of the deep drawing process is in Fig. 3 shown. In this position, both the drawing punch 3 and the drawing die 5 with the metal sheet 8 in contact. The pull bar 7 is shifted by its maximum distance in the drawing groove 9 of the drawing die 5.

In the Fig. 4 to 11 are enlarged sections of two embodiments of a thermoforming device 1 shown. Further embodiments are in the FIGS. 12 to 14 shown. All embodiments show a table 2, a counter-pressure plate 4, a pull bar 7 and pressure pin 11th

A drawing punch 3 and a drawing die 5 is only in the FIGS. 4 . 6 . 8th . 10 . 12 and 14 to see while they are hidden in the other figures.

The counter-holder 4 has a removable plate part 4a. This is easy to dismantle. When the plate member 4a is removed, the pull bar 7 can be taken out and replaced. In this way, the deep-drawing device 1 is particularly easy to convert, if other drawing parameters are set or the wear to be compensated.

The pull bar 7 has a pull bar tool 7a and a pull bar support 7b for the pull bar tool 7a. The pull bar tool 7a is detachably connected to pull bar support 7b. The strip carrier 7b is slidably received in a recess 4b of the counter-pressure plate 4, namely parallel to the direction of movement of the drawing die 5 slidably. In the recess 4b, a guide pin 4c is mounted, which forms a sliding fit with a guide bore 7c of the pull bar support 7b.

On the table facing side of the counter-pressure plate 4 quills 13 are mounted, which introduce a counter-holding force in the counter-pressure plate 4. The counter-holding force can be generated hydraulically, for example.

An embodiment of a deep drawing apparatus is described in greater detail in FIGS FIGS. 4 to 7 shown. This has a pressure pin 11, which is in direct contact with both the pull bar 7 and the table 2 during the stop phase. In operation, a head end of the pressure pin 11 comes into contact with the pull bar 7. A foot of the pressure pin 11 is seated with the table 2 when the stop phase of the deep drawing operation begins. The Fig. 4 and 5 belong together. Fig. 5 shows the same deep-drawing device 1 and the same stage of the deep-drawing process. In both illustrations, the pressure pin 11 in each case the same distance D to the table 2.

To adjust how deep the pull bar 7 is pushed through the flow path F of the metal sheet 8 during the initial drawing phase, as shown in FIG Fig. 5 shown, a spacer 14 is provided. By changing the thickness of the spacer 14, the bead depth of the draw bead can be varied. Of course, spacers can also be stacked to vary by changing the total thickness of a stack, the bead depth. The spacer 14 is arranged in the recess 4b of the counter-pressure plate 4. If the pull bar is inserted into the recess, it can not be lowered to the bottom of the recess, because the spacer 14 forms a stop. Depending on the thickness of the spacer 14, the pull bar projects beyond the level of the surface of the counter-pressure plate 4.

The same thermoforming device 1, as in Fig. 4 and Fig. 5 is again in the Fig. 6 and 7 shown. At this stage, the deep drawing process is completed.

Fig. 6 shows a section of the thermoforming device 1. The pull bar 7 can be seen in cross section. Fig. 7 shows the same stage of the thermoforming process, but as a side view. The metal sheet 8 is completely pulled around the drawing punch 3. The previous distance D of the pressure pin 11 from the table 2 is in Fig. 6 Shrunk to zero. The pressure pin 11 has first come into contact with the table 2. At the moment of this contact, there is still a gap between the Pressure pin 11 and the pull bar 7. By continuing the deep drawing process, the counter-pressure plate 4 further lowered and with her the pull bar 7 until the pull bar 7 abuts the pressure pin. This moment is the beginning of the stop phase of the drawing process. In a continuation of the deep drawing operation, the counter-pressure plate 4 is further lowered until the distance G between the counter-pressure plate 4 and the table 2 has shrunk to zero, as in Fig. 7 to see. During the lowering of the counter-pressure plate 4, the drawing strip 7 was pushed deeper into the drawing groove 9 of the drawing die 5.

The associated Fig. 7 shows a side view of the thermoforming device 1. The thermoforming process is in the same state as in Fig. 6 , The spacer 14 has been lowered with the counter-pressure plate 4 and the drawing die 5. Between the spacer 14 and the pull bar 7, because the pull bar 7 can not be lowered further, a gap S emerged. The pull bar 7, since the moment when it rests on the pressure pin 11, has been prevented from further lowering. In other words, the pressure pin 11 forms when it rests on the table 2, a stop for the pull bar 7. Once the pull bar 7 comes into contact with this stop, the drawing phase is completed and begins the stop phase of the deep drawing process. The existing at the end of the stop phase measure of the gap S between spacer 14 and pull bar 7 corresponds to the path by which the pull bar 7 is moved from the beginning of the stop phase to the end of the stop phase in the drawing groove 9 of the drawing die 5.

In the picture sections of the Figures 5 and 7 each two pressure pins 11 are shown side by side. Depending on the size of the pull bar 7, a plurality of pressure bolts 11 may be provided side by side to support the pull bar 7 evenly. The same applies to spacers 14, of which a plurality of side by side over the length of the pull bar 7 may be distributed in order to support these uniformly and to prevent deflection.

When in the deep-drawing device according to the Fig. 4 to 7 The depth of the initial drawing bead should be greater than in the example shown, it must be the spacer, which in the Fig. 5 and 7 is shown, to be replaced with a spacer with a different thickness.

If a draw part is to be made which requires an earlier or later start of the stop phase, this can be set. The beginning of the stop phase of the drawing process is in the deep drawing according to the Fig. 4 to 7 changed, in which the existing pressure pin 11 is replaced with a shorter or longer pressure pin eleventh

Since the stop phase always begins when the pressure pin 11 has come into contact both with the table 2 and with the pull bar 7, the distance D must be reduced to zero in the course of the drawing process first and also the distance K between the pressure pin 11 and Pull bar 7 to be zero. An earlier start of the stop phase can thus be achieved if at least one of the distances K or D is reduced. This can be done, for example, by using a longer pressure pin 11. The pressure pin 11 can be extended, with the purpose of reducing the dimension K or the dimension K remains and the pressure pin 11 is extended at the opposite end, with the purpose of reducing the dimension D. Of course, the pressure pin can also be extended at both ends.

On the other hand, the stop phase can be changed by bringing an additional spacer element with the pressure pin 11 in series between the pull bar 7 and the table 2. An embodiment of this is based on the 8 to 11 described. The 8 to 11 each show the same thermoforming device. The Fig. 8 and 9 belong together because they show the thermoforming device from two perspectives but at the same stage of the thermoforming process. In Fig. 8 is the pull bar 7 to see, which has deflected the flow path F of the metal sheet 8, in which the metal sheet has been pressed into a drawing groove 9 of the drawing die 5. Of the Drawing punch 3 has not caused any deformation of the metal sheet 8. The pressure pin 11 of the thermoforming device is formed shorter than the pressure pin 11 according to the Fig. 4 to 7 , in addition to the pressure pin 11, a spacer 15 between the pressure pin 11 and pull bar 7 is provided and also between the pressure pin 11 and table 2, an additional spacer 16 is arranged. The latter spacer 16 is arranged on a console which stands on the table 2. In this construction, the spacer 17 located on the bracket 17 forms a stop for the pressure pin 11 and the bracket 17 has a support surface 17 a, which is higher than the spacer 16, and forms a table-side stop for the counter-pressure plate 4. When the drawing die 5 and the counter-pressure plate 4 are lowered in the direction of the table 2 during the deep-drawing operation, initially the distance D between the pressure pin 11 and the spacer 16 is reduced to zero. The depth of the draw bead remains constant during this phase. Upon further lowering of the drawing die 5, the distance K between the spacer 15, which lies on the pressure pin 11, and the pull bar 7 decreases. When the distance K has become zero and the deep-drawing process is continued, the stop phase begins, while pushed the pull bar 7 deeper into the drawing groove 9 of the drawing die 5 and the deflection of the metal sheet 8 is increased. At the same time, a gap S will form between the pull bar 7 and the spacer 14, which in the Fig. 11 is drawn.

Fig. 10 shows the end of the thermoforming process. The drawing punch 3 has completely transformed the metal sheet 8. The pull bar 7 has been moved deeper into the drawing groove 9 of the drawing die 5, as during the drawing phase. During the final phase of the deep-drawing process, it brought about a stronger deflection of the flow path F of the metal sheet 8 and inhibited the flow movement or sliding movement of the metal sheet 8 in the flow path F.

The same stage of the thermoforming process is in Fig. 11 shown. By striking the counter-pressure plate 4 on the support surface 17 a of the console 17 of the deep drawing process is completed. The measure of the gap S between the spacer 14th and the pull bar 7 corresponds to the path by which the pull bar 7 is moved deeper into the draw groove 9 of the draw die 5 during the stop phase.

Further embodiments of thermoforming devices are in the FIGS. 12 to 14 shown. These have adjustable spacers. The same features are provided with the same reference numerals therein as in the previous embodiments.

Fig. 12 is an example of a deep-drawing device, which has a with a pressure pin 11 connected in series distance device 18, the distance measure is adjustable. There are provided two mutually opposed spacer wedges 18a and 18b, of which a spacer wedge 18a is displaceable in the wedge direction. In this way, the total thickness of the wedge pair 18a / 18b is changed. The spacer wedge 18b is attached to one end of the pressure pin 11. This spacer wedge 18b has a distance to the other spacer wedge 18a at the beginning of the deep-drawing process. As the deep drawing process progresses, both spacer wedges 18a and 18b meet, as in FIG Fig. 12 shown. Once a frictional connection between the table 2 and the pull bar 7 is made, the stop phase of the deep drawing process begins. The time of impact of the spacer wedges 18a and 18b is continuously variable by the adjustability of the spacer wedges 18a and 18b.

Fig. 13 shows an embodiment of an adjustable spacer device 19, in which a pair of spacer blocks 19a and 19b is provided, which are formed step-shaped. A spacer block 19b is attached to the pressure pin 11. The associated distance block 19a is arranged on the table 2. The embodiment according to Fig. 13 avoids by its incremental adjustability transverse forces on the pressure pin 11th

In Fig. 14 is between the pressure pin 11 and table 2, a spacer device 20 is arranged, which has an eccentric 20 a. The eccentric element 20a is in a bearing block 20b rotatably received. The point in time at which the pressure pin 11 comes into frictional connection with the table 2 during the deep-drawing process can be varied by rotation of the eccentric element 20a.

LIST OF REFERENCE NUMBERS

1

Deep-drawing device

2

table

3

drawing punch

4

Platen

4a

plate part

4b

recess

4c

guide pin

5

drawing die

6

Press

7

pull bar

7a

Drawing strip tool

7b

Drawing strip holder

7c

guide bore

8th

metal sheet

9

drawing groove

10

drawing bead

11

pushpin

12

stop bead

13

Pinole

14

spacer

15

spacer

16

spacer

17

console

17a

bearing surface

18

spacer device

18a

spacer wedge

18b

spacer wedge

19

spacer device

19a

distance block

19b

distance block

20

spacer device

20a

eccentric element

20b

bearing block

D

distance

F

flow path

G

distance

K

distance

S

gap

Claims (10)

1. Method for the deep drawing of metal sheet (8) by means of a press (6), a table (2), a drawing punch (3), and also a drawing die (5) and a counterpressure plate (4) interacting with the drawing die (5), which together form a flow path (F) for the metal sheet (8), wherein at least one drawing strip (7) movable relative to the counterpressure plate (4) is pushed transversely through the flow path (F) of the metal sheet (8) in order to deflect the metal sheet (8) during a drawing phase (first deflection phase) and the drawing strip (7), for a stop phase, is pushed by a further short distance transversely through the flow path (F) (second deflection stage), wherein a deflection increased once again inhibits the flow of the metal sheet (8) during the second deflection stage, and wherein the metal sheet (8) is essentially plastically formed at the end of the deep-drawing operation, characterized in that the degree of deflection required during the first deflection state is set by means of an interchangeable distance piece (14) which is arranged between the counterpressure plate (4) and the drawing strip (7) and serves as a limit stop.
2. Method according to Claim 1, characterized in that a pressure pin (11) is provided between table (2) and drawing strip (7), and in that the pressure pin (11) is shorter than the distance between the table (2) and the drawing strip (7) during the drawing phase, the distance being reduced during the drawing phase, and the pressure pin (11) being clamped in place between table (2) and drawing strip (7) at the end of the drawing phase or at the beginning of the stop phase, as a result of which the pressure pin (11) directs a pressure force into the movable drawing strip (7) and the drawing strip (7) is lifted from the distance piece (14) serving as a limit stop for the drawing strip (7), as a result of which the drawing strip (7) is displaced into the second deflection stage.
3. Deep-drawing apparatus (1) for metal sheets (8), comprising a table (2), a drawing punch (3), a press (6), a drawing die (5), a counterpressure plate (4), a plurality of drawing strips (7) which are mounted in the counterpressure plate (4) such as to be movable parallel to the press direction of the press (6), and drawing grooves (9) which are provided at the margin of the drawing die (5) and into which the drawing strips (7) can be moved step by step while maintaining a drawing gap, a drawing phase being provided for the purpose of step-by-step forming of the metal sheet (8), during which drawing phase the metal sheet (8) is given a drawing bead (10) having a small bead depth, and at least one stop phase being provided, during which the metal sheet (8) is given a stop bead which has a larger bead depth than the drawing bead (10), characterized in that at least one interchangeable distance piece (14) is provided for the purpose of setting the bead depth of the drawing bead (10) acting during the drawing phase, and in that the distance piece (14) acts between the counterpressure plate (4) and the drawing strip (7).
4. Deep-drawing apparatus according to Claim 3, characterized in that a pressure pin (11) is arranged offset from the distance piece (14) between the drawing strip (7) and the table (2), and in that a pressure force can be transmitted between the table (2) and the drawing strip (7) by the pressure pin (11).
5. Deep-drawing apparatus according to Claim 4, characterized in that the pressure pin (11) is clamped in place between table (2) and drawing strip (7) during the stop phase and is free of pressure during the drawing phase, since the distance between table (2) and drawing strip (7) during the drawing phase is greater than the length of the pressure pin (11).
6. Deep-drawing apparatus according to either of Claims 4 and 5, characterized in that at least one distance element (15, 16, 17, 18, 19, 20) is provided which is arranged in addition to the pressure pin (11) between the table (2) and the drawing strip (7).
7. Deep-drawing apparatus according to Claim 6, characterized in that the distance element provided is a further distance piece (15, 16, 17) having a fixed distance dimension or a distance device (18, 19, 20) having an adjustable distance dimension.
8. Deep-drawing apparatus according to one of Claims 4 to 7, characterized in that the pressure pin (11) is mounted in the counterpressure plate (4) such as to be axially movable, namely movable parallel to the press direction of the press (6).
9. Deep-drawing apparatus according to one of Claims 6 to 8, characterized in that at least one further distance element (15, 16, 17) is arranged between the table (2) and the drawing strip (7) at both ends of the pressure pin (11).
10. Deep-drawing apparatus according to one of Claims 7 to 9, characterized in that the drawing height, by means of the distance pieces (14) which can be used in a variable manner, and the stopping height, by means of the further distance pieces (15, 16, 17) or the distance devices (18, 19, 20), can be set independently of one another.

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