CN113145745A

CN113145745A - Double-station blanking thermoforming tool and method for producing thermoformed and press-quenched motor vehicle parts

Info

Publication number: CN113145745A
Application number: CN202110317918.9A
Authority: CN
Inventors: G·弗罗斯特; M·尼泽; O·吕特克迈尔; J·拉克曼; S·康拉德; U·胡申; J·克斯特
Original assignee: Benteler Automobiltechnik GmbH
Current assignee: Benteler Automobiltechnik GmbH
Priority date: 2015-02-05
Filing date: 2016-02-05
Publication date: 2021-07-23
Also published as: DE102015101668A1; CN105855380A; US20160228934A1

Abstract

The invention relates to a two-station blank-type thermoforming tool (1) for the simultaneous production of two thermoformed and press-quenched motor vehicle components (32), comprising a heating device and a forming device, characterized in that at least two contact heating tools (3) and at least two thermoforming press-quenching tools (4) are arranged parallel to one another on a press (2) in parallel, in order to heat two sheets (5) during the closing movement and to thermoform and press-quench the heated sheets (5.2) into two motor vehicle components (32). The invention also relates to a method for producing a hot-formed and press-quenched motor vehicle component (6, 32) using the double-station blank-type hot-forming die (3) according to the invention, characterized in that two mirror-inverted motor vehicle components (32) are produced simultaneously in one stamping cycle.

Description

Double-station blanking thermoforming tool and method for producing thermoformed and press-quenched motor vehicle parts

The present application is a divisional application of an invention patent application having an application date of 2016, 05/02, 201610236359.8, and entitled "method for producing a thermoformed and press-quenched automotive part by using a double-station blanking type thermoforming mold".

Technical Field

The invention relates to a two-station drop-type thermoforming tool for the simultaneous production of two thermoformed and press-quenched motor vehicle parts, according to the features of claim 1.

The invention also relates to a method for manufacturing a motor vehicle component according to the features of claim 14.

Background

It is known in the prior art to use steel for the manufacture of automotive parts as sheet-formed parts. The steel plate material is put into a stamping forming die, and is subjected to three-dimensional forming through die assembly of the stamping forming die, and then the motor vehicle part is formed.

In addition, the hot forming press quenching technology has been recognized in the prior art. The strength of the motor vehicle component can be increased by heat treatment with the same or even reduced wall thickness. For this purpose, the sheet material can be austenitized, heated to a temperature above the transformation point AC3 and hot-formed in this austenitized state. The method can produce the advantage of instant effect, and the forming freedom degree can be improved due to the heating of the plate. After the forming has ended, the finished motor vehicle component is quench-quenched in such a way that the austenitic material structure is at least partially, in particular completely, transformed into a martensitic material structure with very high strength. This particularly preferably takes place in the stamping die after the stamping process, so that this process is also referred to as press quenching.

EP 2014777B 1 discloses a method and an apparatus for annealing steel sheet bodies, which can heat the metal sheet in a contact heating manner by means of two contact plates. Here, heat can be introduced into the sheet material quickly and specifically, for example, in order to austenitize the sheet material in order to facilitate subsequent hot forming.

DE 102012021031 a1 also discloses a method for producing press-quenched sheet metal parts, in which at least one steel sheet is heated without a heating furnace by means of inductors or by pressing on a contact plate and is then transferred to one or more stamping stations arranged one behind the other.

Disclosure of Invention

The object of the present invention is to provide a method which, starting from the prior art described above, makes it possible to effectively reduce the production costs, the required production surface and the production time for producing hot-formed press-quenched components.

The object is achieved by a two-station drop-off combined thermoforming tool for the simultaneous production of two thermoformed and press-quenched motor vehicle parts according to the features of claim 1.

The method for producing a hot-formed and press-quenched motor vehicle component according to the features of claim 14 is also part of the technical process of this task.

The dependent claims describe advantageous embodiments of the invention.

A two-station blanking thermoforming mold for producing two thermoformed and press-quenched motor vehicle components comprises a region having a heating device and a region having a forming device. The method is characterized in that at least two contact heating dies and at least two hot forming and pressure quenching dies are arranged in parallel in the press, so that two plates can be heated during the die closing movement, and the hot forming and pressure quenching of two motor vehicle parts can be completed in one stamping cycle. The press drive is preferably controlled by one press drive or by a plurality of press drives which are driven synchronously, so that the heating device and the thermoforming device can be brought into a closed position at least for an overlap time or simultaneously.

"double station blanking" according to the present invention means that at least two hot forming press quench molds fall simultaneously, so that two parts can be manufactured simultaneously. The two contact heating dies fall and heat the two plates at the same time, then the two heated plates are transferred into a hot forming and pressure quenching die after the die is opened, and then the dies are closed again to form the plates. Then two new cold plates are put into a contact heating mould for heating. According to the invention, the thermoforming tool can also be designed as a three-station blank. Three parts can then be manufactured simultaneously in one stamping cycle. The thermoforming mold can also be designed to four-station blanking so that four parts can be manufactured simultaneously.

The hot forming die according to the invention for simultaneously manufacturing two hot formed press quenched components is particularly suitable for manufacturing left/right side components. For example, in the case of the production of a motor vehicle body, a left motor vehicle pillar and a right motor vehicle pillar can be produced. It is also possible to manufacture, for example, a door impact beam or a thermoformed compression-hardened reinforcement patch at the same time.

The resulting advantages are in particular a considerable saving in space in the production plant, since the two heating stations, the two conveyors and the two forming presses which are otherwise required for producing two different components are integrated into one combined thermoforming mold in a space-saving manner.

In a preferred embodiment, instead of a transfer device between a separate heating station and a separate forming device, a conveying device is also used. The operating space required for such a transport device, for example the pivoting space of an industrial robot, can thus also be saved in a space-saving manner in the device according to the invention. Furthermore, it is not necessary to drive the four presses which can be moved up and down independently, but all the functions can be integrated into one press. The time required for the transfer of the sheet from the separate heating device to the separate forming device by the transfer device is saved, so that the manufacturing time can be reduced at the same time, and the manufacturing cost of the components can be reduced by less operation cost on the whole. Another advantage is that it is ensured that at the time of delivery of a batch of slabs, in particular at the time of manufacture of the left/right hand parts, no manufacturing deviations of the semi-finished products or raw materials of different delivery batches occur, so that the left/right hand parts manufactured at the same time are of the same quality with respect to the delivery batch of slabs to be processed. Defective products can be reduced, and thus manufacturing costs can be reduced as a whole. The amplitude of the fluctuation of the intensity distribution in the component can be reduced by a shorter transport distance/time, thereby improving the manufacturing quality.

In order to compensate for tolerances which differ from one another and/or due to deformations of the press platen, both contact heating dies and/or both hot-forming press-hardening dies are mounted elastically, in particular elastically, on the upper die of the press. Thermal deformations during operation can be compensated for by elastic mounting or by mounting with another compensating element. The absolute contact time during the closing movement of the press can also be determined by different adaptation of the compensating elements or springs, in particular their length, and/or before the design of the compensating elements or springs. For example, a compensation element or resilient element that is longer than the compensation element or resilient element of the contact heated die may be used to support the hot forming press quench die. When the press performs the closing movement, the hot forming press-quenching die is first brought into contact with the sheet metal material, and the forming process sometimes ends before reaching the bottom dead center while continuing to perform the closing movement. The contact pressure is then increased by the compensating elements and/or springs, by the continued lowering of the press, thus ensuring perfect abutment of the formed sheet in the die cavity. And then the plate can be particularly effectively kept in a bottom dead center for chilling and pressure quenching, and the pressure per unit area is improved, so that the formed plate is in close contact with a corresponding forming half die of a hot forming and pressure quenching die, and the heat conduction is particularly facilitated. Contact heating can then take place simultaneously on the contact heating die during the pressure quenching time. The spring or the compensating element of the contact heating die can also be designed in such a way that the contact heating die is already in full close contact with the sheet to be heated if the press is not yet in the bottom dead center. The press is then closed to increase the contact pressure between the contact heating die and the sheet to be heated, which has a positive effect on the heat transfer due to the increased pressure per unit area and thus improved contact.

The relative support may be formed as follows.

The contact heating die and the hot forming and pressure quenching die can be respectively supported on the upper die or the lower die in a floating mode or together through hydraulic compensation pads. If supported individually, a compensation pad on the upper and/or lower die is provided for each die section, i.e., for each contact heating die and each hot forming press quenching die. If the support is combined, for example, the two contact heating dies can be supported by a common compensation pad, and the two hot-forming press-quenching dies can also be supported on the upper or lower die by a common compensation pad. All the dies can also be supported in a central manner by a common compensation pad on the upper and/or lower die of the press. A floating bearing may be provided so that a translational and/or rotational movement may be achieved with respect to the stroke direction of the press. The hydraulic compensation pads are designed such that a pad, in particular a metal pad, is formed between the rear side or back of the respective die and the punch of the upper die and/or the press platen of the lower die. The mat cover is then filled with a hydraulic medium, in particular a fluid. The pressure in the hydraulic cushion can be set beforehand, but can also be actively adjusted or regulated during the execution of the clamping movement and/or in the clamped state.

If the press is now closed, the contact heating dies and/or the hot forming press quenching dies can perform relative compensating movements when the press is closed, thereby eliminating skewing by the floating support achieved by the hydraulic compensating pads, and enabling perfect mutual alignment of the contact heating dies and the hot forming press quenching dies, which are respectively suspended on the upper die and the lower die of the press, and transferring the pressing force to the sheet to be heated and/or the formed sheet, thereby ensuring uniform close contact. The compensating pad itself is designed appropriately so that it can withstand the pressure occurring during stamping.

The advantages that result are, in particular, that it is possible to form the slides on the punch of the upper or upper die or on the press platen of the lower die, on which slides exchangeable contact heating dies and/or hot-forming press-hardening dies are then mounted so as to be movable relative to one another with the addition of a compensation pad, in order to change the production line. This facilitates the replacement of the die and, due to the floating bearing, does not require the troublesome readjustment or reworking of, in particular, the hot-forming press-quenching die, since relative self-centering is achieved by the floating bearings with respect to one another. It is conceivable that the compensating mat can also be actively controlled, so that the pressure in the compensating mat can be increased, for example, by means of a hydraulic cylinder. When the press is fully closed, high pressure can be injected into the compensation pad, thereby increasing the contact pressure of the contact heating die and/or the hot forming and pressure quenching die.

According to a further preferred embodiment of the support, the contact heating die and/or the hot-forming press-quenching die are mounted on the upper die and/or the lower die so as to be movable relative to one another with the addition of a plurality of spring elements. When the press is closed, the contact heating dies and/or the hot-forming press-quenching dies moving towards each other perform a relative movement due to the elastic elements, thereby ensuring almost complete close contact for contact heating or contact cooling during press-quenching. Even in this case, the contact heating die and/or the hot-forming press-quenching die can be supported, in particular, by the slide on the upper or lower die of the press in a floating manner, so that short assembly and adjustment times can be achieved when changing dies for changing the production line to another product, and complicated adjustment work can be omitted. A lockable spring can also be used.

It is furthermore particularly preferred to use guide means, in particular linear guide means, so that when the floating bearing contacts the heated and/or hot formed press quenching tool, centering can be carried out transversely to the vertical direction on the basis of the linear guide means in the closing direction of the press, so that lateral unintentional shifting of the hot formed press quenching tool and/or the contact heated tool is avoided.

In another preferred embodiment, two thermoforming press-quenching dies are each designed as a combined hot-cutting and hot-punching die. The plate is heated by a contact heating mould and then transferred into a hot forming and pressure quenching mould by a conveying device. The sheet is then shaped in a hot forming press and quenched die and cut and/or punched while still hot. After the forming process is complete, the formed part may be pressure quenched using chilling. Further reworking can then be omitted, which contributes to a reduction in production time and production costs. There is also little wear of the die because the hot cutting or punching is carried out on the relatively soft sheet metal after heating and then no further work is carried out on the already hardened motor vehicle parts. According to the invention, the contact heating die can be designed such that it is capable of heating the plate completely, in particular completely above the austenitizing temperature.

According to the invention, the contact heating die can also be annealed only locally. Some areas of the sheet are not heated at all or slightly below the AC3 temperature, while other areas are heated above the austenitizing temperature. According to the invention, it can also be provided that the sheet metal placed in the contact heating die is first preheated, for example uniformly, to a temperature of less than or equal to the temperature AC1 or to a temperature of less than AC 3. Certain regions are then spot heated in a contact heating die above the AC3 temperature, while regions below the AC3 temperature are either held at this temperature or not annealed at all, but are not intensely cooled.

According to the invention, it is also possible to design the hot-forming and pressure-quenching die in sections such that, for example, locally mutually different cooling takes place when the sheet is heated completely uniformly above the AC3 temperature. Not only annealing that is locally different from each other may occur in the contact heating die, but also quench hardening that is locally different from each other may occur in the hot forming press-quenching die. This makes it possible to manufacture components having regions of strength which locally differ from one another.

It is also conceivable according to the invention to design the contact heating die and/or the hot forming press quenching die separately in sections. The locally mutually different regions can then be annealed and/or quench-quenched by the individual segments, in particular by the separating gaps of the segments, which results in little heat conduction within the die and the sheet or within the hot-forming press-quenching die. The contact heating die and/or the hot forming press quenching die may also be composed of mutually different substances or materials, so that mutually different anneals may be achieved by different heat conduction capacities of each material.

In addition, a conveying device is adopted to transfer the heated plate from the contact heating die to the hot forming and pressure quenching die. The transfer device is especially designed as a linear transfer device which transfers the heated plate material into the hot forming and pressure quenching die in the press. The conveying device is preferably designed as a rack gear or as a 2-or 3-shaft gear. However, the conveying device can also be designed to convey the cold sheet material to the contact heating die and to discharge the finished hot-formed and press-quenched component from the press. However, it is also possible to supply cold plate material and to discharge the finished components by means of a corresponding handling device, for example by means of an industrial robot. It is also possible to provide a plurality of linear conveyors which can be moved simultaneously and which are arranged in succession in the conveying direction offset by the width of the heating or quenching mould.

The time required for the conveying device to transfer the heated sheet from the contact heating die to the hot forming press quenching die is less than or equal to the stamping cycle, preferably less than half of the stamping cycle, and particularly less than one third of the stamping cycle. The opening movement may be performed until top dead centre is reached, and then the closing movement of the press may be performed again, for example the heated sheet may be initially transferred to the hot forming press quench mould half or two thirds of the time the press is open, the press reaches top dead centre and the closing movement is performed again. Before reaching the middle die closing stroke, the conveying device puts the heated plate into a hot forming and pressure quenching die. This brings the advantage according to the invention of rationalizing the production time, in particular when contact heating is started already by the close contact before the bottom dead center is reached. The same principle is applicable to a hot forming press quenching die. The press quenching can be started as long as the forming is finished before the bottom dead center is reached. With both measures described above, the hold time of the press can be shortened again, preferably to zero, so that the manufacturing time as a whole can be shortened.

It is particularly preferred to use a servo press, or alternatively a hydraulic press can be used as the press. In particular, both presses are capable of specifically controlling the mold opening and closing movements and of readjusting the contact pressure in the closing position, so that not only the requirements for contact heating, but also the requirements for hot forming and press quenching in the press can be met.

In a further preferred embodiment, the contact heating die is designed such that it has at least one contact plate, preferably two contact plates, one on the upper die and one on the lower die, and the sheet can then be enclosed between the two contact plates when the press closes. The at least one contact plate may preferably be heated inductively.

In an alternative embodiment, the contact plate itself can also be designed as an electrical conductor which heats up when an electrical current passes through it on the basis of the resistive heating principle, wherein the electrical current is interrupted before it makes contact with the sheet metal in order to avoid short circuits. The close contact of the heating conductor can also ensure that the heat is transferred from the conductor to the plate to be heated.

According to the invention, segmented contact plates can also be used, so that locally mutually different sheet material regions can be heated in a targeted manner.

In the case of an electrical conductor, preferably a planar electrical conductor with one or more gaps is used, the parts separated by the slits or gaps then creating an electrical conductor or current path, through which an electrical current then flows and heats the electrical conductor when the electrodes are connected. It is conceivable that the contact plate may be formed by a plurality of electric conductors, and then the electric conductors may be subjected to different temperature adjustment processes, so that different regions may be formed in the sheet material. To avoid short circuits, the current may be interrupted at the latest just before the contact with the slab. The remaining heat is then released by thermal conduction.

The contact plate may also be heated by other heat sources, for example by thermal radiation or other means of thermal conduction. In the case of a contact plate, heating is preferably effected by means of an inductor. The contact plate itself can release its heat to the sheet metal to be heated by thermal conduction.

In a further preferred embodiment, the contact heating die is designed such that an electrical compensation element is formed. The conductive cross-sectional area is formed such that the contact heated mold becomes an electrical compensation element. The compensating element can be placed on the plate to be heated, then the conductive cross-sectional area of the compensating element and the conductive cross-sectional area of the plate to be heated are added to obtain the total conductive cross-sectional area, and the plate can be uniformly heated or locally and differently heated in a targeted manner through the design of the total conductive cross-sectional area. The contact heating die is designed as a combined heating die which utilizes the heat from the compensating element transferred by contact by heat conduction and the heat generated directly in the sheet by the current. In particular, it is possible to compensate for the changing width and/or thickness of the previously cut sheet material using the electrical compensation element in a targeted manner and/or to influence the heating in the sheet material by changing the electrically conductive cross-sectional area of the compensation element itself, in particular by conducting electrical energy using a uniform cross-sectional distribution.

In a further preferred embodiment, either the contact heating die itself or the hot-forming press-hardening die can also have additional cutting dies and/or punching dies, respectively, so that the punching and/or trimming can be integrated into the production process.

In a further advantageous embodiment, an elastic adjustment mechanism is arranged between the hot-forming press-quenching tool and the upper or lower tool of the press or press, so that the hot-forming process is completed before the press is completely closed and the remaining closing stroke of the press causes the elastic adjustment mechanism to compress. It is also conceivable to arrange such a spring adjustment between the press and the contact heating die. Preferably, multiple spring adjustment mechanisms can be used per die. This means that the thermoforming is finished and starts to remain closed before the press itself reaches the bottom dead centre or the reversal point. Furthermore, the holding closed ends during the upward movement of the press only after the complete passage through the lower reversal point or bottom dead point and the renewed lifting of the upper die. By this measure again the cycle time for the hot forming and press quenching of the sheet metal part is suitably reduced, since the forming has already started very early and ended before reaching the further bottom dead center, the holding time can be used to a maximum extent for the quench quenching of the formed sheet metal part. As a positive side effect, a spring adjustment mechanism may be used to compensate for skewed contact heated dies and/or hot formed press quenched dies. At the same time, the difference caused by the required different stamping forces in the press falling together between the contact heating die and the hot forming press quenching die can be compensated by the elastic adjusting mechanism. The elastic adjusting mechanism is mainly designed as a passive adjusting mechanism, in particular as a compression spring. However, it is also possible to form the active spring adjustment mechanism, for example, by means of an electric, hydraulic or pneumatic actuator. This has the advantage that the press hold-closed time in the bottom dead center can be reduced to zero.

Furthermore, it is particularly preferred to provide an elastic element between the contact heating die and the press platen, which elastic element can compensate for the thermal expansion of the contact heating die, in particular of a segment of the segmented contact heating die. When combined with the use of segmented contact heating dies for localized, mutually different contact heating, the thermal action causes the various elements to expand to different degrees. Due to different temperatures and/or different coefficients of thermal expansion, the segments expand to a different degree from one another. Deviations of a few mm can locally result in a failure to contact the sheet to be heated, so that the heating effect is poor and/or the heating boundary is unclear.

These different thermal expansions can be compensated for by elastic elements on the contact heating die, in particular on the contact heating die segments.

The object is also achieved according to the invention by a method for producing hot-formed and press-quenched motor vehicle components using a two-station blank-type thermoforming tool according to the above-mentioned features, wherein two mirror-inverted motor vehicle components are produced simultaneously in one stamping cycle. The two panels can be heated as well and shaped in a subsequent stamping cycle.

In particular, left/right components can thus be produced, namely a left B pillar and a right B pillar, as viewed in the direction of travel. In particular, the advantages of reduced production times and the use of synergistic effects result, since it is not necessary to use four separate heating or forming devices, but all components are produced simultaneously on one press.

According to the invention, the heating can be carried out on the contact heating mould within 3-20 seconds, especially within 4-10 seconds. At the same time, the forming is preferably carried out for 0.1 to 3 seconds, particularly 1 to 2 seconds, and immediately after the forming, the quench quenching is carried out for 4 to 20 seconds, particularly preferably 5 to 10 seconds.

The following description is directed to other advantages, features, characteristics and characteristics of the present invention. The drawings illustrate preferred embodiments of the invention and,

drawings

FIG. 1 is a side view of a two station drop-type thermoforming mold according to the present invention,

figure 2 the mould of figure 1 with the additional compensating element,

figure 3 is a cross-sectional view of a hot forming press quench die with resilient support,

figure 4 is a partial cross-sectional view of an alternative embodiment,

figure 5 is a schematic top view of a thermoforming mold according to the invention,

figure 6 is a top view of a contact plate designed as an electrical conductor,

figure 7 cross section of a contact heating mould with compensation elements according to the invention,

figure 8 is a detailed view of one embodiment of a hot forming die according to the present invention in relation to a hot forming press quench die,

FIG. 9 is a cross-sectional view of a contact heated mold according to the present invention,

figure 10 shows an embodiment of a three-station blanking die,

figure 11 shows an embodiment of a four-station blanking die,

FIGS. 12-14 are process flows of a thermoforming manufacturing line with a modular thermoforming mold according to the present invention,

figures 15a and b show the lifting function of a linear transport system with fixed gripper elements,

FIGS. 16a and b show the lifting function of a linear transport system with relatively movable gripper elements, an

Figures 17 a-c show an active clamp according to the invention.

Even if repeated descriptions are omitted for the sake of simplicity, the same reference numerals are used for the same or similar parts in the drawings.

Detailed Description

Fig. 1 shows a side view of a two-station blanking thermoforming mould 1 according to the invention. The heating and forming tool 1 has a central press 2, within which press 2 two contact heating tools 3 and two hot forming and pressure quenching tools 4 are arranged. The sheet 5 is placed from the stack into a thermoforming mould 1, heated and pre-formed into automotive parts 6 and press quenched. According to the invention, two motor vehicle components 6 are produced simultaneously using a two-station blanking thermoforming tool. Two sheets 5 are placed in the contact heating die 3. The two sheets 5 previously heated in the contact heating die 3 are simultaneously transferred into the hot forming press quenching die 4 by the conveying device 7 (here, a linear conveying device). When the press 2 of the heating forming die 1 is closed, two sheets 5 placed in the contact heating die 3 are heated, and the heated sheets transferred to the hot forming press quenching die 4 are formed into corresponding automotive vehicle parts 6.

The distance each sheet 5 travels between the contact heating die 3 and the hot forming press quenching die 4 is constant, so that the same temperature drop occurs in each part due to the transfer time.

The hot-forming press-quenching die 4 can also be designed as a hot-punching and/or hot-cutting die, so that punching and/or cutting can also take place simultaneously during forming.

Fig. 2 shows a two-station blank-type thermoforming mold 1 of fig. 1 with an additional arrangement of spring bearings 8. In this embodiment, both the hot-forming press-quenching die 4 and the contact-heating die 3 are elastically supported. The advantage of this is that the relative movement of the upper part 9 and the lower part 10 of the contact heating die 3 or the upper part 11 and the lower part 12 of the hot forming press quenching die 4 can be compensated by the spring support 8 when the press 2 is closed. This primarily relates to differential thermal expansion, but also to possible torsional deformations between the upper die 13 and the lower die 14 during operation of the press 2.

Fig. 3 shows a partial cross section of a press 2 according to the invention in relation to a hot forming press quench mould 4 having an upper part 11 and a lower part 12. The upper portion 11 of the hot formed press quench die 4 is supported on an upper die 13 and the lower portion 12 of the hot formed press quench die 4 is supported on a lower die 14 adjacent a press platen 15 of the lower die 14. The hot forming and quenching die 4 has cooling channels 16 on the one hand and creates a die cavity 17 between a die surface 18 of the upper part 11 and a die surface 19 of the lower part 12 of the hot forming and quenching die 4 on the other hand. As shown, misalignment of the upper and

lower portions

11, 12 of the hot forming press quench mold 4 may occur due to skew, particularly rotation relative to the direction of press stroke 20. To compensate for this misalignment, resilient elements 21 are arranged between the press platen 15 and the lower part 12 of the hot formed press quench mould 4, which spring elements, when continuing the closing movement, suitably compensate the position of the lower part 12 of the hot formed press quench mould 4, so that the formed (not shown in detail) sheet 5 is brought into close, approximately uniform contact with the corresponding mould surface 18 of the hot formed press quench mould 4 in the mould cavity 17. Very good heat dissipation is achieved by almost complete intimate contact. A control line 22 is also depicted, by means of which the elastic element 21 can be locked, for example. The spring element 21 itself can be designed as a mechanical spring, in particular as a helical spring or as a helical compression spring, but can also be designed as a hydraulic or pneumatic spring element.

Fig. 4 shows a partial cross-sectional view of another embodiment of the hot forming press quench mold 4 with a hydraulic pad 23 disposed between the upper mold 13 and the upper portion 11 of the hot forming press quench mold 4. The hydraulic cushion 23 has a cushion cover 24 which is in fluid-tight communication with the upper die 13 of the press 2 on a peripheral rim 25. The corresponding fluid is then arranged in the resulting cavity 26 so that the upper part 11 of the hot forming press quench mould 4 can be moved relative to the upper mould 13 of the press 2. In order to ensure substantial support and the transmission of the entire pressing force in the direction of the pressing stroke 20, a support strip 27 is also arranged such that, when the bottom dead center of the press 2 is reached, a rear face 28 of the upper part 11 of the hot-forming press-hardening tool 4 can be brought into close, form-fitting contact with the upper tool 13 of the press 2 on the basis of the support strip 27, and the entire pressing force can then be transmitted. However, since the relative movement can be carried out on the basis of the hydraulic pads 23, a perfect self-centering of the upper part 11 of the hot forming press quench mould 4 and the lower part not shown in the figures can be ensured before.

Alternatively or additionally, a corresponding floating bearing according to fig. 3 or fig. 4 can also be used on the contact heating die 3.

Fig. 5 is a schematic plan view of the thermoforming mold 1. The figure depicts a conveyor 7 in the form of a linear conveyor 29. After heating, the sheet 5 is conveyed in the conveying direction 30 to a press-hardening tool, which is not shown in any more detail. For this purpose, the transport device 29 is provided with supports 31 which can then grip the sheet 5 by means of contact or gripping devices, not shown in detail, and transport the sheet in the transport direction 30. Also as shown, the area of the slab 5 to the left of the reference drawing plane has been heated to an AC1 temperature, and the area of the slab 5 to the right of the reference drawing plane has been heated to an AC3 temperature. This produces mutually different temperature zones in the sheet 5, which then, after the end of the press-quenching process, produces two mutually

different zones

33, 34 in the finished motor vehicle part 32, the first zone 33 having a lower strength than the second zone 34. The two vehicle components 32 produced may be, for example, a left B-pillar and a right B-pillar of a vehicle body produced simultaneously in one stamping cycle.

Fig. 6 shows a top view of a contact plate 35 designed as an electrical conductor. The contact plate 35 itself has a rectangular structure, and various slits 36 are formed in the contact plate 35, which extend from the top surface to the bottom surface of the contact plate 35 with respect to the drawing direction. This causes the contact plates 35 to be electrically separated by the slits 36, thereby creating current paths 37 through the contact plates 35. If the two electrodes 38 are now connected and the contact plate 35 is energized, current flows through the current path 37 and heats the contact plate 35 as a result of the resistive heating. When the closing movement is performed and/or the panel 5 to be heated is placed on the contact plate 35, the current can be interrupted just before the surfaces come into contact, in order to avoid short circuits. The heat in the contact plate 35 is then released to the panel to be heated due to the close contact of the contact plate 35.

Fig. 7 shows a cross section of a contact heating mould 3 according to the invention. It is clear that on the one hand the sheet 5 to be heated has been inserted, whereas on the upper part 9 contacting the heating die 3 a compensating element 39 is arranged. The electrodes 38 are arranged on the outside on the compensation element 39 so that when the contact heating mold 3 is closed, in particular when the compensation element 39 and the sheet 5 are in close contact, preferably electrically conductive, an electric current is passed through, which not only makes it possible to resistively heat the compensation element 39, but also optionally the sheet 5. The compensating element 39, however, has a residual heat at the same time, so that heat can likewise be introduced into the panel 5 to be heated by heat conduction due to the close contact. It can be seen that the compensating elements 39 have mutually different cross-sectional areas in the transverse direction Q, the entire compensating element 39 being composed of an electrically conductive material. The mutually different cross-sectional areas result in mutually different cross-sectional areas of electrical conduction, so that locally mutually different degrees of heating occur as a result of the current density. Especially at the left and right ends, where the cross section is smaller, a stronger heating than in the middle area occurs due to the higher current density. Since the panel 5 has a constant cross-section, when the electrodes 38 are energized, more current flows through the panel 5 in the outer regions, and therefore more heating occurs there. The sum of the conductive cross-sectional area of the compensating element 39 and the conductive cross-sectional area of the sheet 5 is the total conductive cross-sectional area. Furthermore, an insulating shim plate 40 is depicted on the lower part 10 of the contact heating mold 3, and the insulating shim plate 40 is likewise depicted between the upper part 9 of the contact heating mold 3 and the compensating element 39.

Fig. 8 shows a detailed view of an embodiment of a hot forming die 1 according to the invention in relation to a hot forming press quench die 4. As can be seen again, the upper and

lower portions

11, 12 of the respective hot-forming press-quenching dies 4 are arranged on the upper die 13 and the lower die 14 of the press 2. The lower part 12 of the hot forming press quench mould 4 is supported in the press stroke direction 20 at a distance a relative to the press platen 15 of the lower mould 14. When the closing movement is performed, the upper and

lower portions

11 and 12 of the respective thermo-forming press-quenching dies 4 are brought into close contact with the addition of the sheet 5, and the forming process is finished before the bottom dead center is reached. Continued lowering then causes compression of the respective spring adjustment mechanism 41, causing the lower portion 12 of the hot formed press quench die 4 to move toward the press platen 15 of the lower die 14. The press quenching process has already started during this period because of the cooling flow channel 16 and again ensures that the upper die 11 is almost completely in close contact with the formed sheet 5 and the lower part 12 of the hot forming press quenching die 4 is in close contact with the formed sheet 5, thus ensuring that good heat conduction is established. Furthermore, there are centering devices 42 in the form of centering pins which project out of the lower part 12 of the hot forming press-quenching tool 4 and, when the clamping movement is carried out in the direction of the press stroke 20, project into centering grooves 43 in the upper part 11 of the hot forming press-quenching tool 4. This provides for linear guidance in the direction of the press stroke 20 and in particular avoids lateral deflection of the upper and

lower parts

11, 12 of the hot forming press quench mould 4 due to the resilient support provided by the actuator 41. This embodiment can also be used on contact heating dies 3.

Fig. 9 shows a cross-sectional view of a contact heating die 3 according to the invention, said contact heating die 3 having a plurality of

separate segments

44, 45. The section 44 is in particular a section which is not tempered, whereas the section 45 is a section which has been actively heated to a higher temperature than the section 44. All

segments

44, 45 are thermally isolated from each other by a separation gap 46. The actively heated section 45 expands more than the section 44, so that according to the invention, an elastic element 47, which is suspended from the lower section 45, is arranged on the press platen 15 of the lower die 14, so that thermal expansions can be compensated for by the elastic element 47, in particular in the stamping stroke direction 20. According to the invention, it is therefore also possible to individually support each

segment

44, 45 of the heating die 3 in contact with the spring element 47, in particular in a relatively movable manner, so that the different thermal expansions relative to one another can be compensated by the spring element 47, so that the

individual segments

44, 45 have an approximately full-face close contact with the sheet 5 to be heated. This embodiment may also be applied in turn to the hot forming press quenching die 4. Linear guides 48 are also used, which enable linear guidance in the direction of the punching stroke 20 and reduce shearing transverse to the direction of the punching stroke.

Fig. 10 is a top view of a three-station blanking type combined heating and forming die 1 according to the present invention. For this purpose, the individual sheets 5 are introduced into the heating and shaping tool 1 in the transport direction 30, three sheets 5.1 are first heated simultaneously on the contact heating tool 3, and in the following stamping cycle the three heated sheets 5.2 are simultaneously shaped in the three thermoforming press-hardening tools 4, so that three motor vehicle components 6 are produced simultaneously in one stamping cycle. In this case, a three-station blanking thermoforming mould 1 is described.

Fig. 11 shows an embodiment of a four-station blanking thermoforming mould 1 according to the invention. The slabs 5 are first placed in the heating and forming mould 1 in the transport direction 30 from the slab stack. However, from now on there are only two contact heating dies 3, each of which can heat two panels 5.1 to be heated simultaneously. Each heated sheet 5.2 is then placed on a separate hot-forming and quenching die 4 and four motor vehicle parts 6 are produced simultaneously during the closing movement of the press, i.e. in one press cycle. In this case, a small motor vehicle component 6, for example a reinforcing sheet or the like, is involved. The thermoforming mold 1 is designed in this case as a four-station blanking. It is also conceivable that the contact heating dies 3 may also be arranged side by side in the conveying direction 30 and that the four thermoforming press-quenching dies 4 may also be arranged side by side in the conveying direction 30.

Fig. 12 shows a heating and forming die 1 according to the invention with a contact heating die 3, a hot forming and pressure quenching die 4 and a linear transport system 49 arranged thereon. The contact heating mould 3 is in a double-station blanking form. This means that two sheet materials 5.1, 5.2 can be heated simultaneously in the contact heating die 3. The hot forming and pressure quenching die 4 is also in a double-station blanking form. This means that two heated slabs can be simultaneously hot formed and subsequently press quenched in the hot forming press quench mould 4. The gripping elements are preferably designed as slab grippers 51 and/or tempering grippers 52 and/or product grippers 53. The linear transport system 49 has two rails 50 arranged parallel to one another, on which rails 50 the gripper elements are arranged. Two sheet clamps 51 are arranged from left to right with respect to the plane of the drawing. Two tempering clamps 52 are arranged in the middle with respect to the drawing plane and two product clamps 53 are arranged on the right side with respect to the drawing plane. Therefore, the heating forming die 1 is in a double-station blanking form. But can also be designed into a single-station, three-station, four-station or multi-station blanking form. The total displacement travel G is also plotted in the figure.

According to the embodiment shown here, the clamping element is fixed in position relative to the guide rail 50 with reference to the axial direction 54 of the guide rail 50, the guide rail 50 being movable in its axial direction 54. It is contemplated that the clamping members may also be movable in the axial direction 54 relative to the rail 50.

As also shown, the rails 50 can perform a relative movement 55 inwards perpendicular to their axial direction 54, so that the respective clamping elements are in contact with the sheet 5.1, the heated sheet 5.2 or the motor vehicle component 6.

The linear transport system 49 then performs a transport movement in the axial direction 54 of the guide 50. The final position is shown in fig. 13. The shaped motor vehicle component 6 is placed on a schematically illustrated storage stack 56. And placing the heated sheet 5.2 on a hot forming and pressure quenching die 4. The newly picked sheet panel 5.1 is placed on the contact heating mould 3 and the new sheet panel 5.1 is again ready for heating. The rails 50 then execute a movement outwards, so that all rails 50 and the corresponding clamping elements move outwards in relation to the axial direction 54 of the rails 50 and no longer come into contact with the sheet metal blanks 5.1, 5.2 and the motor vehicle components 6.

A return movement 57 is then carried out in the axial direction 54 of the guide rails 50, in particular the return movement 57 is carried out simultaneously by the two guide rails 50, as shown in fig. 14. The process as shown in figure 12 then begins again. The return rails 50 are moved towards each other so that the jaw members are in contact with the heated sheet 5.2 and the vehicle part 6.

Figures 15a and b show the lifting of the slab by the slab clamp 51. The guide rails 50 have performed a relative movement 55 perpendicular to their axial direction 54 so that the sheet clamp 51 is located below the sheet panel 5.1 with reference to the vertical direction V. The lifting movement is then performed by means of the guide 50 as shown in fig. 15 b. This means that all the guide rails 50 are moved upwards in the vertical direction. The sheet panel 5.1 then lies flat on the panel clamp 51 and is also lifted.

Fig. 16a and b show another alternative embodiment. Here the guide rails 50 are not lifted in the vertical direction V, but only the slab clamp 51. The sheet grippers are supported on the guide rails 50 so as to be movable relative to each other in the vertical direction and can also be raised or lowered.

Figures 17 a-c show a relative movement similar to that of figures 16a and b, except that the sheet clamp 51 is shown here as an active clamp. The jaws are in the open position shown in fig. 17a, whereby the guide rails 50 have performed a relative movement 55 towards each other. The slab clamp 51, which is the active clamp, is then closed as shown in figure 17b and lifted in the vertical direction V as shown in figure 17 c.

Reference numerals

1 heating forming die

2 pressing machine

3 contact heating mould

4 thermal forming press quenching mould

5 sheet material

5.1 sheet to be heated

5.2 heated sheet Material

6 Motor vehicle parts

7 conveying device

8 spring support

Upper part of 93

103 lower part

114 upper part

124 lower part

132 upper die

142 lower die

1514 press platen

16 cooling flow passage

17 die cavity

1811 mould surface

1912 surface of mould

20 direction of stroke of press

21 elastic element

22 control circuit

23 Hydraulic cushion

24 cushion cover

25 frame

26 inner cavity

27 support strip

2811 Back side

29 straight line conveyor

30 direction of conveyance

31 support

32 Motor vehicle component

3332 first region

3432 second region

35 contact plate

36 slit

37 current path

38 electrode

39 compensating element

40 spacer plate

41 adjusting mechanism

42 centering device

43 centering groove

44 segmentation

45 segmentation

46 separation gap

47 elastic element

48 straight line guiding device

49 straight line conveying system

50 guide rail

51 plate clamp

52 temp. regulating clamp

53 product clamp

54 axial direction

55 relative movement

56 storage stack

57 return movement

a distance

G total travel

Transverse direction Q

V vertical direction.

Claims

1. A two-station drop-type thermoforming tool (1) for simultaneously producing two thermoformed and press-quenched motor vehicle components (6, 32) comprises at least two contact heating tools (3) and at least two thermoforming press-quenching tools (4) which are arranged parallel to one another in a press (2) in order to heat two sheets (5) during a closing movement and to thermoform and press-quench two heated sheets (5.2) into two motor vehicle components (32), the contact heating tools (3) having a plurality of segments which are tempered locally differently.

2. The heating and forming die of claim 1, characterized in that the two contact heating dies (3) and/or the two hot forming press quenching dies (4) are elastically supported, in particular on the upper die (13).

3. A thermoforming mould as claimed in claim 1 or 2, characterised in that resilient adjustment means (41) are arranged between the press (2) and the contact heating mould (3) so that the hold closed is started before bottom dead centre is reached and is ended during upward movement of the press (2) only after complete passage through bottom dead centre and the upper mould (13) is lifted.

4. A heated forming die according to any of claims 1 to 3 characterised in that a transfer means (7) is provided to transfer the heated sheet (5) from the contact heating die (3) into the hot forming press quench die (4), particularly from the contact heating die into the hot forming press quench die for a time equal to or less than a press cycle, preferably during a part of a press cycle.

5. Thermoforming tool according to one of claims 1 to 4, characterized in that a mechanical press (2), in particular a servo press, is used, or a hydraulic press (2) is used.

6. A heated forming die according to any of claims 1 to 5, characterised in that the contact heating die (3) has at least one contact plate (35), the contact plate (35) being preferably heated by means of an inductor, or the contact plate (35) being formed by an electrically heatable electrical conductor.

7. A heated forming tool according to any of claims 1-6, characterised in that the contact heating dies (3) each have an electrical compensating element (39), the electrical cross-sectional area of which (39) is the total electrical cross-sectional area, which is the sum of the electrical cross-sectional area of the sheet (5) to be heated, and by the design of which the uniform heating of the sheet (5) or the targeted local mutually different heating is achieved.

8. A heated forming die according to any of claims 1 to 7, characterised in that the contact heating die (3) and/or the hot forming press quenching die (4) are each supported in a relatively movable manner, in particular elastically, on a bed plate of the press (2).

9. A heated forming die according to any of claims 1 to 8, characterised in that the contact heating die (3) and/or the hot forming press quenching die (4) each have additional cutting dies and/or punching dies.

10. A thermoforming tool as claimed in any of claims 1 to 9, characterised in that a resilient adjustment mechanism (41) is arranged between the thermoforming press-quenching tool (4) and the press (2) so that thermoforming is completed before the press (2) is fully closed and the remaining closing stroke of the press (2) causes compression of the resilient adjustment member (41).

11. A heated forming die according to any of claims 1 to 10, characterised in that an elastic element (47) is added between the contact heating die (3) and the press platen (15), which elastic element (47) is able to compensate for the thermal expansion of the contact heating die (3), in particular of the segmented contact heating die (3).

12. A thermoforming mould as claimed in any of claims 1 to 11, characterized in that along the thermoforming mould (1) is provided a linear transport system (49) which is composed of at least two parallel, opposed guide rails (50) which are movable in at least one direction of translation, and on which guide rails (50) clamping elements (51, 52, 53) are arranged, which clamping elements (51, 52, 53) are movable in the axial direction (54) of the guide rails (50), and which clamping elements (51, 52, 53) can be raised and lowered in the vertical direction (V) perpendicular to the axial direction (54) of the guide rails (50).

13. A heated forming die according to any of claims 1-12, characterised in that the guide rails are movable perpendicular to their axial direction and outwards or inwards relative to the heated forming die (1) and/or in their axial direction (54) for conveying the sheet (5) and the motor vehicle parts (32).

14. Method for manufacturing thermoformed and press-quenched motor vehicle parts (6, 32) using the double-station blanked-hot forming die (3) according to at least the features of claim 1, characterized in that two mirror-inverted motor vehicle parts (32) are manufactured simultaneously in one stamping cycle, wherein the sheet (5) is first uniformly preheated, then locally annealed in the contact heating die (3), and then thermoformed and press-quenched.