EP3395965A1 - Hot forming line for producing thermoformed and press-hardened sheet steel products and method for operating the same - Google Patents

Abstract

The present invention relates to a hot forming line (1) and a method for operating the hot forming line (1) with a tempering station (2) and a hot forming and press hardening tool (3). According to the invention, a linear conveyor system (4) is provided to convey the sheet metal blank (11) or the formed sheet steel products (13) through the hot forming line (1).

Description

The present invention relates to a hot forming line for the production of hot-formed and press-hardened sheet steel products according to the features in the preamble of claim 1.

The present invention further relates to a method for operating a thermoforming line according to the features in the preamble of claim 11.

From the prior art it is known to produce steel sheet products by means of hot forming and press hardening. For this purpose, a metal sheet of a hardenable steel alloy is heated to at least a portion of a temperature above the Austenitisierungstemperatur. After heating, the sheet metal blank is placed in this warm state in a hot forming tool and hot formed. After completion of the hot forming process, the formed component is rapidly cooled in the hot forming tool, which uses a hardening of the material structure. This is called a press hardening process.

To carry out such a production process, a heating station, also referred to as a tempering station, is therefore required, as well as a hot-forming and press-hardening tool. Manipulators, usually in the form of industrial robots, are used between the individual stations or tools in order to transfer the board or components from one station to the next.

Such a thermoforming line is for example from the DE 10 2009 014 670 B4 known.

The object of the present invention is to provide a hot forming line and a method for its operation, in which the transport time between the various stations and the design effort for transport are optimized.

The aforementioned object is achieved according to the invention with a thermoforming line according to the features in claim 1.

The procedural part of the object is achieved with the features in claim 11.

Advantageous embodiments of the invention are described in the dependent claims.

The hot forming line for producing thermoformed and press-hardened sheet steel products has at least one tempering station for heating at least one sheet metal blank as well as at least one hot forming and press hardening tool for forming and hardening the heated sheet metal blank to a steel sheet product. It is characterized according to the invention in that along the thermoforming line a linear conveyor system is provided, which is formed of two parallel opposite rails, the rails themselves are translationally displaceable and on the rails gripping elements, below Also called gripper, are arranged, wherein the gripping elements in the axial direction of the rails are displaced and the gripping elements are orthogonal to or with the rails can be raised or lowered. It can also be arranged two rails per page. In this case, the displacement of the gripping elements in the axial direction of the rails can be done either by displacing the rails in the axial direction or by a relative movement of the gripping elements to the rails. The linear conveyor system is thus provided at least over a partial length of the hot forming line so that sinkers can be transported from the tempering station to the thermoforming tool or press hardening tool. Preferably, the linear conveyor system is provided along the entire hot forming line.

The linear conveyor system is thus provided along the entire hot forming line. Consequently, a sheet metal blank is picked up by a blank stack or a blank provided by a blanking device and transported through the hot forming line and deposited the finished sheet steel product at a storage location. It is thus possible to dispense with separate manipulators, in particular industrial robots, between the individual stations. According to the invention, the individual stations of the thermoforming line can thereby be locally moved closer to one another or adjoin one another immediately adjacent to one another. The space required in a production hall for setting up such a hot forming line is thereby reduced.

In particular, furthermore, the linear conveyor system can be operated synchronously with a plurality of gripping elements, in particular in the cycle time of the hot forming line. This makes it possible to optimize the cycle times of the entire hot forming line, in particular to shorten, and to reduce the transfer times. The energy required to operate the linear conveyor system but also z. B. to warm up the board and / or keeping the board warm can be reduced. The cycle time is preferably less than or equal to 10 seconds. The cycle time for the tempering can preferably be less than or equal to 6 s, in particular less than or equal to 4 s. The cycle time for the hot forming and press hardening is preferably less than or equal to 6 s, in particular between 4 s and 6 s.

In particular, the linear conveying system according to the invention is suitable for a multiple falling hot forming line, in particular two times or four times or even five times falling hot forming line. This means, in the context of the invention, that two sheet metal blanks are picked up in parallel and inserted into the tempering station. Following this, the two sheet-metal blanks heated at least in sections in the tempering station are in turn received in parallel, and placed in a hot-forming and press-hardening tool. The hot forming and press hardening tool has two shaping cavities, so that the two at least partially heated sheet metal blanks are hot worked together in parallel and also press hardened in parallel. The two steel sheet products produced thereby are then picked up in parallel and placed on a stack of stacks.

In particular, hardened steel sheet products are produced for the automotive industry, for example motor vehicle structural components or motor vehicle body components.

The linear conveyor system is particularly preferably further characterized in that active grippers are provided for gripping a metal sheet. The active grippers perform a clamping movement. In particular, these are provided, for example, as a scissor gripper. In particular, the active grippers are designed as platinum grippers and tempering grippers, very particularly preferably at least as gripper pairs on the two rails lying parallel to one another, one gripper each of the gripper pair being arranged on one of the two rails lying parallel to one another. Thus, in a circuit board, which sags in the raised state due to gravity with the clamping movement of the active gripper safe transport are possible.

For gripping a finished sheet steel product passive grippers are preferably provided. Passive grippers grab the sheet steel product in particular in the vertical direction from below and lift it. Due to the effect of gravity, the steel sheet product remains on the passive gripper. In particular, the passive grippers are designed as product grippers. The sheet steel product has a higher resistance to deflection, wherein a passive gripper is structurally less expensive compared to an active gripper and thus less error prone. The gripping elements, but especially the passive grippers are arranged to grip underneath the component.

The above-described gripping elements are arranged on the rails. Depending on the design variant of the rails themselves, this means that they slide from outside over the rails or else are arranged inside the rails. In particular, the gripping elements are coupled to the rails in such a way that, on the one hand, they can move in the axial direction of the rails, but at the same time are linearly guided.

The rails can themselves be made, for example, as an extruded profile. The gripping elements can be stored, for example, ball-bearing or roller bearings stored in or on the rails. However, they can also be coupled with a sliding bearing with the rails. Preferably, all the gripping elements are displaceable in the axial direction of the rails via a synchronous drive.

Thus, the movement of the gripping elements in the axial direction can be performed synchronously and thus in the same cycle. The synchronous drive can be, for example, a rack drive or even a belt drive.

Alternatively, the gripping elements can also be fixed in position with respect to the axial direction of the rails with these. This means a movement of the rails in the axial direction also causes the gripping elements to be moved in the axial direction. The rails are then also moved via a synchronous drive in the longitudinal direction.

In a further preferred embodiment variant, the main movement of the gripping elements for transport takes place by a movement of the rails in their longitudinal direction. For this purpose, it is possible for at least two gripper pairs, ie two grippers spaced in a longitudinal direction on a rail, to be mutually variable in their relative spacing in the longitudinal direction of the rails. Consequently, the grippers perform a relative movement in the longitudinal direction of the rails, so that, for example, a mutually different distance between two recorded by a temperature control boards for storing in a forming tool can be adjusted. However, the main transport movement is performed by the movement of the rails in the longitudinal direction.

However, the gripping elements are still preferably relative to the vertical direction relative to the rails displaced. Again, it is possible via an electric, hydraulic, pneumatic or even a belt drive, thus lifting a mechanical drive, the gripping elements relative to the rails relative to the vertical direction or lower. Also preferably, it is again possible here that the gripping elements are also arranged fixed in position with respect to the vertical direction on the rails. A lifting movement of blanks or sheet steel products is thus carried out by lifting the entire rails in the vertical direction.

Further preferably, the rails are orthogonal to their axial direction and relative to the hot forming line displaced outwards. This can also be done via a synchronous drive, so that both rails are simultaneously moved outward, thus perform an opposite movement. The inserted sheet metal blanks and the heated sheet metal blanks placed in the hot forming and press hardening tool can then be processed in the respective station, preferably in one cycle. When the processing, thus the cycle has ended, the tempering station and the hot forming and press-hardening tool are opened and the rails are displaced inwards and execute an aligned movement. Sheet metal blanks or steel sheet products can then be picked up with the gripping elements. Subsequently, the gripping elements perform the movement in the axial direction of the rails.

A translational travel of the rails in a horizontal plane orthogonal to the longitudinal direction is preferably only between 5 mm and 250 mm, preferably 10 mm to 50 mm from a rest position to a gripping position. Due to the very short time due to the small travel path of the rails themselves turn the time required for conveying, compared to an industrial robot significantly shortened. The cycle times between the press cycles can thereby be reduced and the energy required to extend the movement can also be reduced.

With particular preference the tempering station and the press frame with hot-forming and press-hardening tools are arranged close to one another. This means in the context of the invention that the distance between press frame and tempering is less than 2 m, preferably less than 1 m, in particular less than 50 cm. However, these are particularly preferably formed directly adjacent to each other. This means that the distance is a few centimeters or directly next to each other. Thus, the distance is less than 10 cm, in particular less than 5 cm remain so that the hot forming and press hardening tool is decoupled from the tempering. The decoupling relates in particular to vibrations and temperature lines and kinematic motion sequences. In particular, can be realized with the linear conveyor system according to the invention in the longitudinal direction of the rails, thus in the horizontal direction of Gesamtverlagerungsweg of recording the board to the filing of the manufactured component, a total length of less than 15 m, in particular less than 10 m. Thus, about 2 m for the tempering, 2.2 m for the press frame of the hot forming and press hardening tool, each 1 m for an inlet and outlet and the remaining remaining space in the longitudinal direction of the receptacle for temperature control and forming provided boards and a storage container used to store ready-made components. These data refer to double falling versions of tempering station and thermoforming tool. Preferably, tempering station and hot forming and press hardening tool are arranged on separate machine foundations. The advantage is that smaller standard presses can be used both for the tempering station and for the hot forming and press hardening tool. For example, for the hot forming and press hardening tool, a press having a pressing force of 1500 to 2500 t, especially 1800 to 2200 t, and preferably 2000 t, may be used. For the tempering a press with a pressing force of 20 to 100 t, in particular 30 to 70 t, preferably 50 t can be used.

In a further preferred embodiment variant, however, it is possible for the tempering station to be coupled directly to the hot-forming and press-hardening tool. In particular, the tempering station is flanged to the press frame. In addition, it is possible that the tempering station is controlled parallel to the drive of the hot forming and press hardening tool and both stations operate synchronously or in the same cycle. For this purpose, the temperature control, in particular the same control preferably also the same drive, have as the hot forming and press hardening tool in the press frame.

In particular, it is thus possible to synchronously open or close the tempering station and the hot forming and press hardening tool via the same drive. The opening or closing movement thus takes place in the same press cycle. Alternatively, it is also advantageous if the tempering station is opened with respect to the hot forming and press hardening tool delayed in time or downstream. Thus, in particular with contact heating due to the application of tempering plates, a better heat effect or, after opening of the tempering station, a lower cooling rate results. Only when the hot forming tool is open, or shortly before the start of the transport of the heated blanks in the hot forming tool thus the temperature control is opened.

The present invention further relates to a method of operating the hot forming line described above. For this purpose, a board is gripped and transported by axial movement of at least two opposing Platinengreifern in the tempering and stored in this. Parallel to this, a board heated in the tempering station is gripped by at least two opposing tempering grippers in the tempering station and conveyed into the hot-forming and press-hardening tool and deposited there. Again, in parallel, a hot worked and hardened steel sheet product from the hot forming and press hardening tool is gripped by at least two opposing product grippers and conveyed to a discard pile or the produced steel sheet products are conveyed to the discard pile by a downstream transfer system.

Figur 1 bis 3

den Verfahrensablauf einer erfindungsgemäßen Warmformlinie,

Figur 4a und b

ein Warmumform- und Presshärtewerkzeug mit seitlich angeflanschter Temperierstation,

Figur 5

ein Warmumform- und Presshärtewerkzeug mit seitlich angeflanschten Temperierstationen,

Figur 6

ein Warmumform- und Presshärtewerkzeug zu Figur 5 in alternativer Ausgestaltungsvariante,

Figur 7a und

b eine Anhebefunktion eines Linearfördersystems mit festen Greifelementen,

Figur 8a und

b eine Anhebefunktion eines Linearfördersystems mit relativbeweglichen Greifelementen,

Figur 9a bis c

erfindungsgemäße Aktivgreifer,

Figur 10

eine Warmformlinie mit teilbarer Schiene und

Figur 11

eine Warmformlinie mit Temperierstation und Warmumform- und Presshärtewerkzeug mit einem Abstand kleiner 50 cm zueinander.

Further advantages, features, characteristics and aspects of the present invention are explained in the following description. Preferred embodiments are shown in the schematic figures. These are for easy understanding of the invention. Show it:

Figure 1 to 3

the procedure of a hot forming line according to the invention,

FIGS. 4a and b

a hot forming and press hardening tool with laterally flanged tempering station,

FIG. 5

a hot forming and press hardening tool with laterally flanged tempering stations,

FIG. 6

a hot forming and press hardening tool FIG. 5 in alternative embodiment variant,

Figure 7a and

b a lifting function of a linear conveying system with fixed gripping elements,

Figure 8a and

b a lifting function of a linear conveying system with relatively movable gripping elements,

FIGS. 9a to c

active gripper according to the invention,

FIG. 10

a hot forming line with divisible rail and

FIG. 11

a hot forming line with tempering station and hot forming and press hardening tool with a distance of less than 50 cm to each other.

In the figures, the same or similar parts the same reference numerals are used, even if a repeated description is omitted for reasons of simplicity.

FIG. 1 shows a thermoforming line according to the invention 1 comprising a tempering 2 and a hot forming and press hardening tool 3 and arranged thereon a linear conveyor system 4. The linear conveyor system 4 has two mutually parallel rails 5, wherein 5 gripping elements are arranged on the rails. Based on the image plane from left to right two Platinengreifer 6 are arranged. Relative to the image plane in the middle, two tempering grippers 7 are arranged and two product grippers 8 are arranged on the image plane relative to the right side. The hot forming line 1 is thus two times falling. It can also be simple, triple, quadruple or multiple falling. Further, a Gesamtverlagerungsweg 6 is shown.

According to the variant shown here, the gripping elements are fixed in position relative to the rails 5 in the axial direction 9 of the rails 5, the rails 5 being movable in their axial direction 9. Alternatively, it would also be enforceable that the gripping elements in the axial direction 9 to the rails 5 are displaced.

Furthermore, it is shown that the rails 5 have a relative movement 10 with respect to the axial direction 9 orthogonal running inwards. The respective gripping elements are thus brought into engagement with the sheet metal blanks 11, the sheet metal blanks 12 or the sheet steel products 13 to be heated.

The linear conveyor system 4 then performs a transport movement 14 in the axial direction 9 of the rails 5. The end position is in FIG. 2 shown. The formed sheet steel products 13 are deposited on a storage stack 15 shown schematically. The heated sheet metal blanks 12 are deposited on the hot forming and press hardening tool 3. The newly recorded metal blanks 11 are deposited on the tempering 2 and there are again new metal blanks 11 ready. Following this, the rails 5 carry outward movement 16, so that the entire rails 5 with the respective gripping elements are moved outward relative to the axial direction 9 of the rails 5 and are no longer in engagement with the sheet metal blanks 11, 12 and sheet steel products 13 stand.

Then, in the axial direction 9 of the rails 5, a return movement 17 is performed, in particular, this return movement 17 is carried out synchronously with both rails 5, as in FIG. 3 shown. Thereafter, the process begins again as in FIG. 1 shown. The returned rails 5 are moved towards each other so that the gripping elements engage with the heated sheet metal blanks 12 and the sheet steel products 13.

FIGS. 4a and b show the hot forming line 1 according to the invention in each case in a side view. The rails 5 can be seen. Sheet metal blanks 11 received by a sheet metal blanks stack 18 are fed to the tempering station 2. The tempering station 2 is optionally flanged to the press frame 19. According to FIG. 4b have thermoforming and press hardening tool 3 and tempering station 2 synchronously performed a closing movement and heat the inserted into the tempering 2 sheet metal blanks 11 and form the heated sheet metal blanks 12 to the steel sheet products 13, which are stored on a storage stack 15. The tempering station 2 in this case has an actuator 20, so that the tempering 2 can be controlled independently of the hot forming and press hardening tool 3. The actuator 20 may be arranged at the top and / or bottom of the temperature control station 2.

FIG. 5 shows an alternative embodiment variant of the hot forming line 1 comprising a hot forming and press hardening tools and the downstream separate tempering station 21, the tempering stations 21 and the hot forming and press hardening tool 24 are connected to a common control unit 22. A control unit 22 controls all individual stations isochronous or even simultaneously. Preferably, in all units shown in the figures vibration damper 23 can be used in the coupling. The tempering station 21 is used for local softening or other local structural adjustment of the press-hardened steel sheet product.

FIG. 6 shows an embodiment variant according to FIG. 5 with the difference that the tempering station 2 and the tempering station 21 are coupled to an upper tool 25 of the hot forming and press hardening tool 24 or its press frame 19, so that the opening and closing movement of the upper tool 25 is performed isochronous and simultaneously with the tempering 2.

FIGS. 7a and b show a lifting operation of the rails 5 with the platinum grippers 6. The rails 5 have a movement 10 orthogonal to the axial direction 9 running towards each other, so that the Platinengreifer 6 are located in the vertical direction V below the sheet metal blank 11. Following this is a lifting movement, shown in FIG. 7b executed by the rails 5. This means that the entire rails 5 are moved upward in the vertical direction V. As it is then the sheet metal blank 11 on the platinum grippers 6 and is also raised.

FIGS. 8a and b show an alternative embodiment variant. Here are not the rails 5 are raised relative to the vertical direction V, but only the platinum gripper 6. These are thus relatively movable with respect to the rails 5 mounted on the vertical direction V and can also be raised or lowered.

FIGS. 9a to c indicate an analogue relative movement 10 FIGS. 8a and b with the difference that here the Platinengreifer 6 are shown as active gripper. These are in an open position according to FIG. 9a represented, so that the rails 5 have performed a mutually directed movement 10. According to FIG. 9b then the platinum grippers 6 are closed as active gripper and according to FIG. 9c again raised relative to the vertical direction V.

FIG. 10 shows the hot forming line 1 according to the invention in an idle state. The upper rail 5, which is related to the image plane, is displaced outwardly in the axial direction 9 in a doubly divided manner. This allows a free access 26 to the hot forming and press hardening tool 3 located behind it, so that a schematically indicated tool change 27 can take place. Following this, the two rail parts are again moved towards each other, coupled together and the hot forming line 1 operated.

Furthermore, it is shown that two gripper pairs arranged in the middle, relative to the image plane, which are in particular tempering grippers 7, are mutually variable in their distance A1. This makes it possible to record two tempered blanks 21 at a distance B1 from the tempering station 21 and to deposit them in the hot forming and press hardening tool 24 by increasing the distance A1 of the tempering grippers 7 relative to one another in the axial direction 9 of the rails 5 with a spacing B1. The width B2 is greater than the width B1.

FIG. 11 shows a thermoforming line 1. The tempering 2 and the hot forming and Presshärtewerkezug 3 are arranged close together with a distance 28 of less than 50 cm. The temperature control station 2 and the hot forming and press hardening tool 3 can be driven synchronously. This can be done via a common control or by superordinate control of two connected individual controls. Important is a common opening phase, so that the linear conveyor system 4 can make a respective transport in a short time.

Reference numerals:

1 -

Thermoforming line

2 -

heating station

3 -

Hot forming and press hardening tool

4 -

Linear conveyor system

5 -

rail

6 -

platinum gripper

7 -

Temperiergreifer

8th -

product gripper

9 -

Axial direction to 5

10-

relative movement

11 -

sheet metal blank

12 -

heated sheet metal plate

13 -

Steel sheet products

14 -

transport movement

15 -

discard pile

16 -

Movement to the outside

17 -

Return movement

18 -

Sheet metal blank stack

19 -

press frame

20 -

actuator

21 -

heating station

22 -

control unit

23 -

vibration

24 -

Hot forming and press hardening tool

25 -

upper tool

26 -

free access

27 -

tool change

28 -

distance

A1 -

distance

B1 -

distance

B2 -

distance

V -

vertical direction

Claims (14)

A thermoforming line (1) for producing thermoformed and press-hardened sheet steel products (13), comprising a tempering station (2) for heating at least one sheet metal blank (11) and a hot forming and press hardening tool (3), characterized in that along the thermoforming line (1) a linear conveying system (4) is provided, which is formed from at least two parallel opposing rails (5), wherein the rails (5) are displaceable in at least one translational direction and on the rails (5) gripping elements are arranged, wherein the gripping elements in the axial direction (9 ) of the rails (5) are displaceable and that the gripping elements orthogonal to the axial direction (9) of the rails (5) can be raised and lowered, wherein the hot forming and press hardening tool (3) and the tempering (2) at a distance of less than 2 m, preferably less than 1 m, in particular less than 50 cm are arranged. Thermoforming line according to claim 1, characterized in that the Gesamtverlagerungsweg of receiving a board to the filing of the manufactured component has a total length of less than 15 m, in particular less than 10 m. A thermoforming line according to claim 2, characterized in that a length of 2 m is used for the tempering station (2) and / or that a length of 2.2 m is used for the press frame (19) of the hot forming and press hardening tool (3) / or that each 1 m be used for an inlet and outlet. Thermoforming line according to one of claims 1 to 3, characterized in that for the hot forming and press hardening tool (3) a press with a pressing force of 1,500 t to 2,500 t, in particular 1,800 t to 2,200 t, preferably 2,000 t is used. Thermoforming line according to one of the preceding claims, characterized in that a press with a press force of 20 t to 100 t, in particular from 30 t to 70 t, preferably 50 t, is used for the tempering station (2). Hot forming line according to one of claims 1 to 5, characterized in that a translational travel of the gripping elements between 5 and 250 mm, in particular 10 to 50 mm is provided from a rest position to a gripping position. Thermoforming line according to one of claims 1 to 6, characterized in that the tempering station is flanged to the hot forming and press hardening tool (3) or that the tempering station and the hot forming and press hardening tool are arranged directly next to each other, with a distance (28) smaller than 50 cm , in particular less than 20 cm, preferably less than or equal to 10 cm. Hot forming line according to one of claims 1 to 7, characterized in that the tempering station (21) is controlled isochronous to the drive of the hot forming and press hardening tool (24) or that the tempering (21) for the opening movement relative to the hot forming and press hardening tool (24 ) is driven downstream. Hot forming line according to claim 1, characterized in that the tempering station (2) and the hot forming and press hardening tool (3) are opened or closed synchronously via the same drive. Thermoforming line according to claim 1, characterized in that the thermoforming line (1) is formed twice falling, so that 2 sheet metal blanks (11) are simultaneously heated and two steel sheet products (13) are simultaneously thermoformable and press-hardened. Method for operating a thermoforming line (1) having the features of at least claim 1, characterized in that a Sheet metal plate (11) is gripped and transported by axial movement of at least two opposing Platinengreifern (6) in the tempering (2) and stored in this, wherein in parallel a heated sheet metal plate (12) of at least two opposing Temperiergreifern (7) in the tempering (2) is gripped and conveyed into the hot working and press hardening tool (3), wherein two deformed and hardened steel products (13) are simultaneously taken from the hot working and press hardening tool (3) from at least two opposing product grippers (8) and be transported on a stack of trays (15) or that a downstream transfer of ready-made steel products (13) on a stack of trays (15). Method for operating a hot forming line according to claim 11, characterized in that an opening movement of the tempering station (2) is carried out downstream of the opening movement of the hot forming and press hardening tool (3). Method for operating a hot forming line according to claim 11 or 12, characterized in that in a twofold falling hot forming line (1) two transport movement of two sheet metal blanks (11) and / or steel products (13) exporting pairs of gripper elements in their distance (A1) in the axial direction (9 ) are mutually variable. Method for operating a hot forming line according to one of Claims 11 to 13, characterized in that a time for transporting a sheet metal blank (11) or the sheet steel product (13) is less than 5 s, in particular less than 3 s.

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