WO2015090590A1

WO2015090590A1 - Method, furnace installation, and system for hot stamping of workpieces

Info

Publication number: WO2015090590A1
Application number: PCT/EP2014/003410
Authority: WO
Inventors: Gmbh Ruhstrat; Tobias Meint; Axel WEILAND; Wilhelm Meyer; Peter Vervoort
Original assignee: Eisenmann Se
Priority date: 2013-12-19
Filing date: 2014-12-17
Publication date: 2015-06-25
Also published as: DE102013021584B4; DE102013021584A1

Abstract

During a method for hot stamping of workpieces, the workpieces (4) are heated in a furnace installation (8) to a shaping temperature before they are shaped in a shaping process. Individual workpieces (4) or workpiece groups made of two or more workpieces (4) are heated separately by means of an induction device (34) in a separate moveable furnace module (20) having an individual module housing (22). A furnace installation (8) for a system for hot stamping of workpieces (4) comprises multiple separate moveable furnace modules (20) having an individual module housing (22) and an induction device (34), wherein an individual workpiece (4) or a workpiece group made of two or more workpieces (4) can be inductively heated in each furnace module (20). In addition, a system is specified for hot stamping of workpieces using a furnace installation (8) of this type.

Description

Method, oven device and system for the form hardening of workpieces

The invention relates to a method for the form hardening of workpieces, in which the workpieces are heated in a furnace device to a ümformtemperatur before they are formed in a forming process.

In addition, the invention relates to a furnace device for a plant for the form hardening of workpieces, in which workpieces are heated to a forming temperature before they are formed in a forming process, and a plant for the form hardening of workpieces with a furnace device, in which workpieces are heated to a forming temperature , And a forming device in which the heated

Workpieces are deformable.

Form hardening has become particularly established as a method for hot working metal parts into components, in particular in the automotive industry, and is also familiar under the terms press hardening or hot stamping. The workpieces to be reshaped are heated in a furnace device, transferred by means of a transfer device, such as a multi-axis robot, from the furnace device to a shaping device, where they are shaped by a pressing tool into the desired component.

For example, workpieces made of sheet steel are heated to a forming temperature between about 800 ° C and 1100 ° C during so-called austenitization. In practice, the forming temperature for steel sheets made from common boron-manganese steel alloys is 930 ° C. Frequently, such steel sheets are provided with an aluminum-silicon coating (AlSi). Such a steel sheet workpiece, for example

CONFIRMATION COPY a flat steel sheet or board or even in a previous step, for example by cold drawing, be preformed sheet steel part. Subsequently, the heated workpiece is formed in the forming device with a cooled pressing tool and

at the same time deterred. As a result, the material structure changes during the molding process and the components obtained have a considerably higher strength and rigidity than components that have been cold-formed from the workpiece.

During the transfer of the workpiece from the oven device to the forming device, the previously heated workpiece cools down. The extent of this cooling depends on the period of time that elapses from the removal of the workpiece from the oven device to forming. However, the quality of the components obtained in the case hardening can vary considerably when different workpieces with different temperatures are formed. It is therefore important that the time required from removal from the oven device to forming in the forming device and the prevailing ambient conditions are as possible reproducible for all workpieces.

In order to heat the workpieces to the required forming temperature, various furnace concepts are known. At present there are especially continuous furnaces on the market where the workpieces are conveyed through a furnace tunnel with a conveyor system. Usual are roller kilns, in which the workpieces on a roller conveyor in the

Pass through the oven promoted.

The sampling point is always the same, so that a reproducible handling of the workpieces from the sampling point to the forming is guaranteed. On the one hand, however, the space required for such a continuous furnace is relatively high. On the other hand, the position and orientation of the workpieces on the rollers may change during transport through the oven. This is particularly the case with AlSi-coated steel sheets, as the AlSi coating may become loose on the rollers during transport and build up on the rollers over time. As a result, the rollers are deformed, which can lead to the rotation of the sheets during movement.

Another reason for a change of position of the workpieces on the rollers may be voltage changes in the workpieces and deformations caused thereby, whereby the contact areas of the workpieces may shift on the rollers. This in turn can lead to a movement of the workpieces on the rollers, by which they change their position.

As a result, the position and alignment of the workpiece must first be determined precisely in an automated removal so that a robot can pick up the workpiece correctly and a perfect transfer of the workpiece to the forming device is ensured, including the positioning of the workpiece in the pressing tool. Also, workpiece carriers for the workpieces often do not help here, since their position on the roller conveyor during the passage can also change accordingly.

However, during the required position detection, the heated workpiece already comes into contact with the environment and can cool down, at least in peripheral areas. This in turn leads to quality losses in the resulting components.

In addition to the continuous furnaces, so-called batch ovens have become established in which there are several stationary ovens in which The workpieces are not moved and their loading and unloading by robots. Although this technique ensures the position and alignment of the workpieces, they can be positioned on workpiece carriers. However, there is the way the workpieces from the sampling point to the forming device of each oven from different, so that no reliable reproducibility of the travel time of the workpieces to the forming device and thus the reproducibility of the components obtained can be guaranteed.

It is an object of the invention to provide a method, a furnace device and a system of the type mentioned, which take into account these ideas and in particular lead to a good throughput in the form hardening of workpieces.

This object is achieved in a method of the type mentioned in that individual workpieces or workpiece groups of two or more workpieces are heated separately in a separate, movable furnace module with its own module housing by means of an induction device.

In technical terms, both a single workpiece and a workpiece group with two or more workpieces are referred to as a "batch". In accordance with the invention movable furnace modules, one or more workpieces can be reproducibly placed in the furnace module, possibly also with the help of a workpiece carrier, which is anchored stationarily in the furnace housing.

Then a complete furnace module can be moved to a robot, where it can also be reproducibly positioned to the robot, so that the alignment of the Workpiece in the oven based on the robot is known. There is thus no delay in detecting and picking up a heated workpiece by a robot. In addition, the space required compared to a continuous furnace can be reduced.

By the induction device a particularly effective heating of the workpieces is possible. In particular, inductive heating can take place considerably faster in comparison to electrical heating units with heating coil, IR radiators or even gas burners, so that the overall throughput of the installation as a whole can be increased.

In this case, it is favorable in terms of material handling if several furnace modules are moved as a module group.

Particularly preferably, the furnace modules are moved alternately between a loading position in which the furnace modules are loaded with a workpiece and a transfer position in which a workpiece is removed from the furnace modules. The oven modules can be moved between the positions back and forth, for example, on a linear route. However, it is particularly advantageous if the oven modules are moved on a revolving path. The term "surrounding track" this case is basically just so To Hide ^¬ hen that the path is closed, does not mean that the furnace modules must also be moved absolutely outstanding and / or only in one direction on the surrounding track.

Preferably, however, the furnace modules are moved in circulation. In this case, there is an effective delivery circuit, which ensures a high throughput, which corresponds to the throughput of the Forming device can be adjusted.

Conveying technology, it is advantageous if the oven modules are moved in a horizontal plane on a horizontal circumferential path.

Alternatively, the oven modules may be moved in a vertical plane on a vertically circulating path.

In a further alternative, the furnace modules can also be largely rotated on the spot about an axis of rotation, in particular about a vertical axis of rotation. The loading position and the transfer position are then defined by the orientation of the furnace modules with respect to the axis of rotation.

The above object is achieved in a furnace device of the type mentioned above in that the furnace device comprises a plurality of separate, movable furnace modules with their own module housing and an induction device, wherein in each furnace module, a single workpiece or a workpiece group of two or more workpieces is inductively heated ,

The advantages correspond to the advantages explained above for the method.

Accordingly, it is favorable if a conveyor system having Wenig ^¬ least one conveyor is provided with a plurality of furnace modules are movable as a module group.

The at least one conveyor device is preferably set up in such a way that the oven modules can be loaded alternately between a loading position in which the oven modules can be loaded with a workpiece and a transfer position. wegbar are in which a workpiece can be removed from the furnace modules.

Advantageously, the conveyor is set up such that the oven modules are movable on a revolving path.

Again, it is advantageous if the circulating track is a horizontal circumferential path in a horizontal plane.

Alternatively, the orbiting track may be a vertically revolving track in a vertical plane.

Another type of movement is opened when the conveyor comprises a rotating device, with which the oven modules are largely on the spot about a rotation axis, in particular about a vertical axis of rotation, rotatable.

The throughput can be effectively increased if the conveyor comprises at least two floors in which oven modules are moved.

In order to be able to use each floor individually, it is favorable if for each at least two floors in each case a separate circulating horizontal conveyor is available.

Alternatively or additionally, the throughput can be increased by having at least two furnace units, each comprising a conveyor and an associated module group. In this case, two such furnace units are operated in parallel.

In a plant of the type mentioned above, the above object is achieved in that the furnace device is a furnace device with some or all of the features mentioned above for the furnace device.

The advantages correspond to the above-mentioned advantages mutatis mutandis.

In addition, it may be advantageous if at least two forming devices are present, to which workpieces can be supplied via a common furnace unit or a plurality of furnace units, wherein a furnace unit in each case comprises a conveying device and an associated module group.

Embodiments of the invention will be explained in more detail with reference to the drawings. In these show:

Figure 1 is a side view of a system for the molding of

Workpieces with a furnace device, which for a respective workpiece comprises a separate, movable furnace module, wherein a furnace unit according to a first embodiment comprises a module group of two furnace modules and a turntable on which the furnace modules are arranged in a common horizontal plane;

Figure 2 is a top view of the system of Figure 1;

Figure 3 is a top view of a modified plant with several furnace units according to Figures 1 and 2;

Figure 4 is a side view of a system with a furnace device with a furnace unit according to a second embodiment, comprising a module group of two furnace modules and a rotary column, in which the furnace modules arranged vertically one above the other are;

Figure 5 is a top view of the plant of Figure 4, wherein two furnace units are present;

Figure 6 is a top view of a system with a

Oven device in which a furnace unit according to a third embodiment comprises a module group with a plurality of furnace modules, which are movable in a horizontal plane on a revolving path;

Figure 7 is a top view of a modified plant with a furnace unit of Figure 6 and a furnace unit according to a fourth embodiment, the furnace modules rotate on a longer horizontal orbit;

Figure 8 is a side view of a system with a furnace device, in which a furnace unit according to a fifth embodiment comprises a module group of a plurality of vertically stacked furnace modules, which is movable on a linear vertical path;

Figure 9 is a side view of a plant with a furnace device, in which a furnace unit according to a sixth embodiment comprises a module group of a plurality of furnace modules, which are movable in a vertical plane on a revolving path;

Figure 10 is a top view of the system of Figure 9 with two oven units; Figure 11 is a side view of a modified plant, which corresponds to the system of Figures 9 and 10 and in which the circumferential path as a seventh embodiment is a circular path;

Figure 12 is a top view of the system of FIG

11, wherein two furnace units are present;

Figure 13 is a side view of a modified system, which corresponds to the system of Figures 11 and 12 and in which the oven units have a front cover as eighth embodiment;

Figure 14 is a top view of the system of FIG

13;

Figure 15 is a top view of a modified plant with a furnace unit according to Figures 11 and 12, wherein two forming means are present;

Figure 16 is a top view of a system with a

Furnace device in which a furnace unit according to a ninth embodiment comprises a module group of a plurality of furnace modules, which are movable on a linear horizontal path;

Figure 17 is a top view of a system with a

Oven device in which a furnace unit according to a tenth embodiment comprises a module group with a plurality of furnace modules, which are movable in a horizontal plane on a revolving path, wherein a Beladelücke remains on the web. The figures with 2 total a plant for Formhär referred to, in which workpieces 4 are formed into components 6. The workpieces 4 are, for example, workpieces made of sheet steel, as explained above.

The plant 2 comprises a furnace device 8, in which the workpieces are heated to a forming temperature. When a workpiece 4 has reached its forming temperature, it is removed from the oven device 8 with the aid of a transfer device 10 and transferred to a forming device 12. This comprises, in a manner known per se, a cooled pressing tool 14, with which the workpiece 4 is deformed and quenched into the component 6 in a forming process. After a predetermined residence time in the pressing tool 14, in which the now produced component 6 cools to a final temperature, the component 6 is released and removed by means of a removal device 16 from the forming device 12 and then its further determination, such as a mechanical post-processing supplied ,

Both as a transfer device 10 and as Entnahmeein ^¬ direction 16 multi-axis articulated robot 18 can be used, as they are known in and for themselves for handling Werkstü ^¬ bridges; In the present case, therefore, a transfer robot 18a and a removal robot 18b are present.

As can be seen in the figures, the oven device 8 comprises a plurality of separate oven modules 20, each with its own module housing 22, which delimits a furnace chamber 24. Optionally, various furnace modules are also referred to below as 20a, 20b and so on. In the figures, not all furnace modules 20 are always provided with reference numerals.

The oven chamber 24 is accessible from the outside via an opening 26 in the module housing 22, which is released via a module door 28 or can be closed. In the oven chamber 24 is a workpiece carrier 30, which stores a single workpiece 4 or a group of workpieces of two or more workpieces 4 during heating. The workpiece carrier 30 ensures proper positioning of the workpiece or workpieces 4 with respect to the oven module 20. The workpiece carrier 30 may in particular be made of reaction-bonded silicon-infiltrated silicon carbide SiSiC.

In all figures, furnace modules 20 are illustrated, in each of which only a single workpiece 4 can be heated. This basically reflects the ideal case, but can not always be achieved, taking into account the required space requirements and the throughput rate of Annex 2.

Therefore, if a workpiece group of two or more

Workpieces 4 are to be heated in a furnace module 20, builds the module housing 22 respectively correspondingly higher and the workpiece carrier 30 are several carrier floors before. In this case, the module housing 22 may have a respective opening 26 at the level of each of these carrier levels and comprise a module door 28 for each of these openings 26.

The furnace modules 20 of a system 2 need not be identical. There may also be various furnace modules 20 whose dimensions, in particular the volume of the furnace chamber 24 and the cross section of the opening or openings 26, are respectively adapted to different types of workpieces 4 or to a different number of workpieces 4 to be accommodated.

Each furnace module 20 operates autonomously and for this purpose carries at least one own heating device 32 with it. In the present case, the heating device 32 is an induction device 34 with an nem inductor 36, by means of which the or the workpieces 4 are heated inductively. For an effective inductive heating, the inductor 36 is adapted to the geometry and the dimension of the workpieces 4. In particular, when the workpiece 4 is present as a circuit board, the workpiece can also be accommodated between two contact plates of the induction device 34 not shown here, which in turn are heated by the inductor 36 and give off the heat to the workpiece 4, as in the article by Vasily Ploshikhin, "Tailor-made lightweight components made of steel", VDI-Z 155 (2013), No. 3, p. 18ff, is explained.

In a modification not specifically shown, a muffle may additionally be arranged in the furnace chamber 24 of a furnace module 20, which additionally encloses the workpiece carrier 30 tightly. The muffle can provide a uniform temperature distribution and protect the furnace chamber 24 and there special components of the heater 32 from impurities such as scale or coating components that can fall in the furnace module 20 from the workpieces 4. A protection of heating components can be done without muffle on an encapsulation of the components in question; with a muffle this is not necessary, so that this structural complexity can be omitted and costs can be reduced if necessary.

If a protective gas atmosphere is needed, the

Protective gas consumption is reduced because the muffle has a smaller volume than the furnace chamber 24. Also, the furnace walls must not be freed to the extent as usual of oxygen and water.

Each oven module 20 is supplied via a line bundle 38 with necessary to operate electrical or fluid resources. This includes, in particular, the energy supply of the heating device 32, to which the line bundle speaking at least one electrical line comprises. In special cases, a separate furnace atmosphere can be generated in the furnace modules 20, in which the workpieces 4 are heated and which is different than the ambient atmosphere. In this case, the line bundle also includes fluid lines, via which an atmosphere gas can be blown into the furnace chamber 24 or the furnace atmosphere can be sucked off. The individual lines of the line bundle 38 lead to the individual supply sources or delivery components, which are not shown here specifically.

A schematically indicated only in FIG. 1 process control 40 monitors the correct operation and the parameters of the individual furnace modules 20. Each furnace module 20 is equipped for this purpose with corresponding sensors which monitor the operating parameters of the furnace module 20 and send corresponding output signals to the process control 40. The line bundle 38 comprises for this purpose in addition to the mentioned supply lines corresponding data lines.

If a fault occurs in a particular furnace module 20, for example if the heater 32 of a particular furnace module 20 fails, that furnace module 20 can be selectively detected. The defective furnace module 20 can then be separated from the working process and maintained separately, without this significantly influencing the other course of the forming process or even temporarily leading to a standstill of the process. Through the individual furnace modules 20, an individual heating process can be run through from each workpiece 4, which can be controlled separately for each workpiece 4 via the process control 40. on the reference numerals 22 to 38 are only in Figure 1 all shown. In the remaining figures, the associated components are provided for clarity only with reference numerals if it appears useful in connection with the description.

The furnace modules 20 are guided past the transfer robot 18a by means of a conveyor system 42. The conveyor system 42 comprises one or more conveying devices 44, each of which can each move a plurality of oven modules 20 as a module group 46. A conveyor 44 and the associated module group 46 in turn form a furnace unit 48 of the oven device 8. Various embodiments of the oven units 48 are designated in the figures with 48.1, 48.2, 48.3, etc.

Generally speaking, the conveyor 44 is like a ^¬ mentioned passage configured such that the furnace modules 20, alternating between a loading position, in which the furnace modules 20 can be loaded with a workpiece 4, and a transfer position can be moved, in which a workpiece 4 from the furnace modules 20 can be removed. The loading can be done manually by a worker or automated; a loading device, with which a workpiece 4 can be moved into a furnace module 20, is not specifically shown in the figures.

The conveyor system 42 and the respective conveyors 44 are illustrated only very schematically in the figures; Drive or guide components or means for powering the conveyors 44 are not shown. The drive of the furnace modules 20 can be done for example by chain or cables. Given case is also a roller track in question, are placed on the rollers of the Ofenmo ^¬ modules 20, wherein the furnace modules optionally be gegebenen- 20 out laterally to a change in position currency to prevent transport. Also, a respective entrained by a furnace module 20 drive comes into consideration, so that the furnace modules 20 can be designed even driving with a corresponding chassis.

If in the embodiments described below, a plurality of identical furnace units 48 are present, they are labeled 48a, 48b, etc. Each furnace unit 48 defines a respective own transfer position and loading position for the furnace modules 20 of this furnace unit, wherein a furnace unit 48 can also specify different transfer positions and loading positions for different furnace modules 20 of their module group 46. This is the case, for example, in the embodiment of FIG. 4 explained below.

In principle, the system 2 operates in such a way that a furnace module 20 is loaded with a workpiece 4 in the loading position, while the transfer robot 18a removes a workpiece 4 heated to its forming temperature from a furnace module 20 in the transfer position.

While the freshly loaded oven module 20 is moving in the direction of the transfer position, the workpiece 4 located therein is heated to its forming temperature.

In a modification, the transfer robot 18a can simultaneously work as a loading device and bring workpieces 4 into furnace modules 20 from a workpiece depot. In this case, the loading position and the transfer position can also be identical; The robot then first removes a heated workpiece 4 from a furnace module 20, transfers this workpiece 4 to the forming device 12, removes a fresh workpiece 4 from a workpiece depot and introduces it into the now empty oven module 20. The module door 28 of a furnace module 20 can be operated by a motor and opened via a control command when the furnace module 20 reaches its transfer position in front of the transfer robot 18a. When the workpiece 4 has been removed, the module door 28 is closed again. In a mechanical way, the module door 28 can be actuated, for example, via a gate in which a stationary actuator at the transfer position causes the module door 28 to open when the furnace module 20 reaches its transfer position. When the furnace module 20 is again moved away from the transfer position, the module door 28 is again separated from the actuator and closes the opening 26. In Figures 1 and 2 is now in a system 2, a furnace device 8 with a furnace unit 48.1 according to a first embodiment shown. There, the conveyor 44 of the furnace unit 48.1 is a turntable 50 with a turntable 52, which is rotatable by a motor about a vertical axis of rotation. The turntable 52 carries two furnace modules 20a, 20b, the module doors 28, and thus also their openings 26, facing radially outward. The module group 46 thus comprises two furnace modules 20 there; However, more than two oven modules 20 may be positioned on the turntable 52. The movement of the oven modules 20 thus takes place in a horizontal plane on a horizontally circulating path, which is a circular path on the basis of the turntable 50.

The line bundle 38 of each oven module 20 is in a conventional manner by rotary feedthroughs through the

Rotary plate 52 passed. The power supply and data transmission can also be done via sliding contacts.

The oven module 20a assumes its transfer position while the opposite oven module 20b is in the loading position. tion is located. While a workpiece 4 is introduced into this furnace module 20b, an already heated workpiece 4 can be removed from the furnace module 20a and transferred to the forming device 12. Then, the turntable 50 is rotated and the oven module 20b is moved to the transfer position and the oven module 20a is moved to the loading position. The rotation time takes into account the time required for the heating of the workpiece 4. FIG. 3 shows a plant 2 in which the furnace device 8 comprises several, in the concrete case four, furnace units 48a.1, 48b.1, 48c.1 and 48d.l with turntable 50, which are arranged in a circle around the transfer robot 18a , The transfer positions in the individual furnace units 48.1 are thereby selected such that the time required for the movement of a workpiece 4 by the transfer robot 18a from a furnace module 20 into the pressing tool 14 of the converting device 12 is always substantially the same regardless of From which oven unit 48.1 the workpiece 4 was removed.

Thus, all heated workpieces 4 remain in the ambient atmosphere for the same duration and it is ensured that all components 6 obtained after forming have the same quality, regardless of which oven unit 48.1 they originate from.

If the movement paths for different workpieces 4 originating from different transfer positions differ considerably from those of the forming device 12, this can be compensated by the process control 40, which also communicates with the transfer robot 18a. This is then programmed for each transfer position with different motion ^¬ patterns, the duration of which, however, is the same length to the filing of the work-5 piece 4 in the pressing tool 14. This applies in principle to a system 2 for work hardening of workpieces and thus also for all embodiments and modifications described herein.

FIG. 4 shows in a system 2 a furnace device 8 with a furnace unit 48.2 according to a second exemplary embodiment. This comprises as a conveyor 44, a rotating device, which is here in the form of a rotary column 54 with two floors 56a, 56b. The furnace modules 20 are largely rotated in place about a vertical axis of rotation.

On each floor 56a, 56b, respectively, a furnace module 20a and 20b is arranged, wherein the module doors 28 have in opposite directions and the lower furnace module 20a in the e- days 56a its transfer and the upper furnace module 20b in the floor 56b assumes its loading position , In general, in the respective loading position of the oven modules 20, their module doors 28 are away from the transfer robot 18a, whereas they face the latter in the respective transfer position.

In a modification not specifically shown, in each floor 56a and 56b also a plurality of furnace modules 20 may be arranged, each forming a module group 46. Then the furnace modules 20 are again aligned so that their module doors 28 point radially outward. Then the movement of the oven modules 20 of a module group 46 is again a movement on a horizontally circulating path.

The height levels of the floors 56a and 56b are tuned so that the path of movement which a workpiece 4 travels from the lower furnace module 20a and the upper furnace module 20b to the former 12 is ideally mirror symmetric to a horizontal plane that is level with the position lies, in which the workpiece 4 during forming in the Pressing tool 14 is located. This ensures in a simple manner that the workpieces 4 have the same residence time in the ambient atmosphere, independently of the floor 56a or 56b of the oven unit 48.2, from which they are taken.

As can be seen in FIG. 4, the rotary column 54 comprises, for each floor 56a, 56a, a support plate 58 on which the respective furnace module 20a or 20b rests. In a modification not specifically shown, such support plates 58 can also be dispensed with and two furnace modules 20 can be placed directly on one another and fastened to one another.

FIG. 5 shows a plant 2 in which the furnace device 8 comprises several, in the concrete case two, oven units 48a.2 and 48b.2 with rotary column 54. These are related to the transfer robot 18a now arranged such that the time required for the movement of a workpiece 4 by the transfer robot 18a from a furnace module 20 into the pressing tool 14 of the forming device 12 is always the same, regardless of, from which rotary column 54 and which floors 56a, 56b, the workpiece 4 has been removed.

Figure 6 shows a system 2, wherein the furnace device 8 comprises, as a third embodiment of a furnace unit on ^¬ 48.3. There, the conveyor 44 is designed as a circulating horizontal conveyor 60, by means of which the oven modules 20 of the local module group 46 are moved in a horizontal plane on a horizontal circulating path 62. The openings 26 with the module doors 28 of the oven modules 20 always have a radially outward direction relative to the track 62 during the circulation.

The loading of the furnace modules 20 can take place there at different positions in the direction of circulation downstream from the transfer position, which depends, for example, on the duration of the transfer Heating of the workpieces 4 and the duration for a full rotation of a furnace module 20 can be selected.

In a modification not specifically shown, several, in particular two, such furnace units 48.3 with circulating horizontal conveyors 60 can be arranged next to each other and assigned to the transfer robot 18a, comparable to the arrangement according to FIG. 5, where two rotary columns 54 are present.

The transfer positions of the oven units 48.3 with circulating horizontal conveyor 60 are then again tuned so that the residence time of the workpieces 4 in the ambient atmosphere regardless of their sampling point can be the same size.

In another variation not specifically shown, the conveyor 44 of a furnace unit 48.3 may also include two or more recirculating horizontal conveyors 60 vertically stacked and each conveying furnace modules 20 to height levels corresponding to those of the two floors 56a, 56b at the pivot 54 (FIGS. see Figure 4). Generally speaking, at least two floors each have their own circulating horizontal conveyor 60 and the conveyor 44 thus comprises at least two floors in which oven modules 20 are moved. In this way, the oven modules 20 per floor can be moved independently of the one or the other floors.

In a further modification, which is also not shown, even with a circulating horizontal conveyor 60, two oven modules 20 with or without intermediate support plate can be arranged one above the other, as explained above for the rotary column 54, so that a circulation floor horizontal conveyor for the furnace modules 20 is formed. With such a conveyor 44, the oven modules 20 of all floors are moved in the same way. Figure 7 shows a system 2, wherein the furnace device ^¬ which the fourth embodiment includes 8 adjacent to the furnace unit 48.3 with a recirculating Horizontalför 60, a furnace unit 48.4, in which the conveyor 44 is formed as a long-circulating horizontal conveyor 64th With this example, longer heating times of the workpieces 4 can still be achieved with good number of cycles of Appendix 2.

Optionally, with such a long-distance circulating horizontal conveyor 64 and two forming devices 12 are operated in parallel, in which different components 6 are made of different workpieces 4.

Workpieces 4 with a long heating time are then heated in the oven unit 48.4 with the long-distance circulating horizontal conveyor 64. Workpieces 4, which are intended for a second forming device 12, are then moved past in their furnace module 20 to the transfer robot 18a for the first forming device 12 and thereafter arrive at a second

Transfer position. In principle, any horizontally circulating tracks 62 can be realized here, which can be adapted to the local circumstances and the desired process sequences. Even with the long-distance circulating horizontal conveyor 64, the openings 26 with the module doors 28 of the oven modules 20 in circulation with respect to the local track 62 always radially outward.

If the required number of cycles of the system 2 specifies it, during the time in which the furnace module 20 of the long-distance circulating horizontal conveyor 64 past the transfer robot 18 a ^¬ leads, a workpiece 4 from the transfer robot 18 a from the circulating horizontal conveyor 60 and transferred to the forming device 14. Also, workpieces 4 can be removed after forming in the forming device 12 and placed in an empty furnace module 20 of the long-distance circulation horizontal conveyor 64 in order to be promoted with this to a further treatment station. Thus, the workpiece 4 can be reheated on the way there again to a certain temperature. If appropriate, the further treatment station may be a second forming device 12, which again transforms the component then obtained from the first forming device 12.

In general, it may be the case that two forming devices may be present, to which workpieces can be fed via a common oven unit 48 or a plurality of oven units 48.

FIG. 8 shows a plant 2 in which the furnace device 8 comprises a furnace unit 48.5 according to a fifth exemplary embodiment. In this furnace unit 48.5, the conveyor 44 includes a linear vertical conveyor 66, which receives a plurality of furnace modules 20 arranged one above another and can move the thus formed module group 46 in the composite on a linea ^¬ ren vertical path.

The linear vertical conveyor 66 thus defines a number of floors 68a, 68b, etc. corresponding to the number of furnace modules 20 present. In the present Ausführungsbei ^¬ game four floors 68a, 68b, 68c and 68d are present. The individual oven modules 20 rest on support plates 70, which may optionally be dispensed with if the oven modules 20 can be stacked directly on one another.

The transfer robot 18a is located at ground level. Thus, the furnace modules can be passed in the vertical direction at the Überga ^¬ beroboter 18a 20, a pit 72 is provided, into which the module group 46 downward establis- ren, so that each furnace module 20 can get into the transfer position in front of the transfer robot 18a.

In order to reduce the lifting work to be performed for lifting the module group 46, it is also possible, for example, to move two such module groups 46 in opposite directions so that the two module groups 46 form a counterweight to one another.

In the plant 2 shown in FIG. 9, the oven device 8 comprises a furnace unit 48. 6 according to a sixth exemplary embodiment. There, the conveyor 44 has a circulation vertical conveyor 74, in which a module group 46 of a plurality of furnace modules 20 in a vertical orbital plane on a vertically revolving path 76 are movable. The oven modules 20 are mounted in such a way that they always remain aligned horizontally during circulation.

Here, the vertical orbit 76 defines a lower conveying path 78a and an upper conveying path 78b in which the oven modules 20 are moved in a horizontal direction, and two vertical conveying paths 80a, 80b connecting them, in which the oven modules 20 are moved in a vertical direction , The direction of rotation is indicated by a round arrow. Accordingly, a furnace module 20 arrives with a horizontal movement on the lower conveying path 78a into the transfer position in front of the transfer robot 18a; in FIG. 9, the furnace module labeled 20a assumes the transfer position.

The oven modules 20 are aligned so that their opening 26 with the module door 28 crosses the vertical orbital plane so that the opening 26 always faces the transfer robot 18a. Optionally, the oven modules 20 may also be rotatably mounted about a vertical axis on the rotary vertical conveyor 74 so that they can be rotated for loading with a workpiece 14 such that the respective opening 26 is arranged parallel to the orbital plane.

In a modification, all the oven modules 20 may be arranged such that the openings 26 are arranged parallel to the circulating plane, without in this case a

Rotatability of the furnace modules 20 is necessary.

In any case, the furnace module 20a moved to take the workpiece 4 to the transfer robot 18a is moved in a horizontal direction. This facilitates the correct positioning of the oven module 20 relative to the transfer robot 18a.

The loading position can be, for example, the position at the top of the vertical conveyor line 80a above the transfer position, which is assumed in FIG. 9 by the oven module labeled 20b. However, a furnace module 20 can also be loaded in other positions in the conveying direction away from the transfer position with a workpiece 4. FIG. 10 shows a plant 2 in which the furnace device 8 comprises two such furnace units 48a.6, 48b.6 with circulating vertical conveyors 74. There, the average of each three oven modules 20 to be recognized in the conveying planes 78a and 78b are omitted. The two furnace units 48a.6, 48b.6 are again arranged so that the paths of movement of the workpieces 4 of both furnace units 48a.6, 48b.6 are largely the same.

FIG. 11 shows a modified plant 2, in which, as the seventh exemplary embodiment, a furnace unit 48. run-vertical forerunner 82 specifies a vertical circumferential circular path 84. For this purpose, the circulating vertical conveyor 82 may, for example, comprise a type of vertical rotary carousel 86 with support arms 88 which can be rotated about a horizontal axis, wherein a furnace module 20 is suspended at the end of each support arm 86. Again, the furnace modules 20 always remain horizontally aligned during circulation.

In the variant shown in FIG. 11, the furnace modules 20 are arranged such that the openings 26 and the module doors 28 are arranged parallel to the circulating plane. The access of the transfer robot 18a to a furnace module 20a in the transfer position thus takes place to a certain extent from the side.

FIG. 12 shows an installation 2 in which the oven device 8 comprises two such oven units 48a.7, 48b.7 with a circulation vertical conveyor 82. The two furnace units 48a.7, 48b.7 are here laterally offset due to the access from the side to the transfer robot 18a arranged so that the movement paths of the workpieces 4 4 of both furnace units 48a.7, 48b.7 are substantially the same.

FIG. 13 shows a modified system 2 in which, as the eighth exemplary embodiment, a furnace unit 48.8 comprises a circulating vertical conveyor 90, which corresponds to the circulating vertical conveyor 82 according to FIG. 11, but additionally has a front cover 92 which encloses the openings 26 of all Furnace modules 20 of the module group 46 covers. In this case, one or more module doors 28 may be dispensed with in the oven modules 20. So that the workpieces 4 can be guided into and removed from the oven modules 20, the front cover 92 has a loading passage 94 matching the loading position and a removal passage 96 matching the transfer position, the transverse sections of which extend to the openings 26 of the module housing 22. are.

In this case, the furnace modules 20 carry sealing means 98, which are identified in FIG. 14 and which surround the respective opening 26 of a furnace module 20 and seal against the front cover 92 during the movement of the module group 46.

A functionally corresponding cover or Teileinhau- solution may also be provided in the other above-mentioned conveyors 4. In the turntable 50 and the rotary column 54 such a cover would, for example, a hollow cylinder and the respective module group 46 would be radially surrounded.

FIG. 14 shows an installation 2 in which the oven device 8 comprises two such oven units 48a.8, 48b.8 with circulating vertical conveyor 90 and front cover 92. The two furnace units 48a.8, 48b.8 are here again laterally offset due to the access from the side to the transfer robot 18a, so that the paths of movement of the workpieces 4 of both furnace units 48a.8, 48b.8 are largely the same.

FIG. 15 again shows a modified plant 2 with a furnace device 8, in which a furnace unit 48. 7 operates with a circulating vertical conveyor 82 according to FIG. There, instead of a forming device 12, two forming devices 12a, 12b are present, which has already been mentioned above. Basically, two more than a shaping device 12 may be present in all the above-mentioned Appendices ^¬ gen.

FIG. 16 illustrates a plant 2 in which the furnace device 8 comprises a furnace unit 48. 9 according to a ninth exemplary embodiment. In this furnace unit 48.9, the conveyor 44 comprises a linear horizontal conveyor 100, which is a module group 46 of several side by side arranged furnace modules 20 can move in a composite on a linear horizontal path. The loading position is located there next to the transfer position, which is occupied by the oven module 20a. The loading position can be provided directly next to the transfer position or even further away.

FIG. 17 shows a plant 2 in which the furnace device 8 has a furnace unit 48.10 as the tenth exemplary embodiment. There, the conveyor 44 is designed as a circulating cycle horizontal conveyor 102, by means of which the oven modules 20 of the local module group 46 are again moved in a horizontal plane on a horizontal circulating path 62, as it corresponds in principle to the oven unit 48.6 of Figure 6. The openings 26 with the module doors 28 of the oven modules 20, however, do not face radially outward in the circulation with respect to the web 62, but always point in the same direction towards the transfer robot 18a.

In the previously discussed rotary conveyors 60, 64, 74, 82 and 90, the furnace modules 20 of the associated module group 46 are arranged at the same distance from each other on the movement path 62, 76 or 84. In the circulating cascade horizontal conveyor 102, however, a gap 104 remains between two furnace modules 20a, 20b, so that a furnace module 20a adjacent to the gap, which is thus in the loading position, is accessible for loading with a workpiece 4.

The oven modules 20 are then cascaded and cyclically shifted by one place, wherein in a cascade cycle the first moving oven module 20 is first moved into the gap 102. At the end of a cascade cycle, this furnace module 20 is moved again, so that the gap 102 is released again. In the other circulating conveyors 60, 64, 74, 82 explained above, the furnace modules 20 can be moved continuously or intermittently in circulation, wherein a standstill of the furnace modules 20 in the loading position and the transfer position is favorable, since so a proper positioning of the workpieces 4 in the Oven modules 20 and a precise removal of the workpieces 4 is facilitated. But also a removal "on the fly" can be realized there, ie the furnace modules 20 do not have to come to a standstill, but can be unloaded during their movement simultaneously with the robot movement.

Claims

claims

1. A method for work hardening of workpieces, wherein the workpieces (4) in a furnace device (8) are heated to a forming temperature before they are formed in a forming process, characterized in that individual workpieces (4) or workpiece groups of two or more workpieces (4) are heated separately in a separate, movable furnace module (20) with its own module housing (22) by means of an induction device (34).

2. The method according to claim 1, characterized in that a plurality of furnace modules (20) are moved as a module group (46).

3. The method according to claim 1 or 2, characterized in that the furnace modules (20) in alternation between a loading position in which the furnace modules (20) are loaded with a workpiece (4), and a transfer position to be moved, in which a workpiece (4) is removed from the oven modules (20).

4. The method according to claim 2 or 3, characterized in that the furnace modules (20) on a revolving path (62, 76, 84) are moved.

5. The method according to claim 4, characterized in that the furnace modules (20) are moved in circulation.

6. The method according to claim 4 or 5, characterized in that the furnace modules (20) are moved in a horizontal plane on a horizontally revolving path (62).

7. The method according to claim 4 or 5, characterized in that the furnace modules (20) are moved in a vertical plane on a vertically revolving path (76, 84).

8. The method according to claim 2 or 3, characterized in that the furnace modules (20) are largely rotated in place about a rotational axis, in particular about a vertical axis of rotation.

9. furnace device for a system for the molding of

Workpieces in which workpieces (4) are heatable to a forming temperature before they are formed in a Umformpro- process, characterized in that the furnace means (8) a plurality of separate, movable furnace modules (20) with its own module housing (22) and a Induction device (34), wherein in each furnace module (20), a single workpiece (4) or a workpiece group of two or more workpieces (4) is inductively heated.

10. furnace device according to claim 9, characterized in that a conveyor system (42) with at least one conveyor (44) is provided, with the plurality of furnace modules (20) as a module group (46) are movable.

11. furnace device according to claim 9 or 10, characterized in that the at least one conveyor (44) is arranged such that the furnace modules (20) in alternation between a loading position, in which the furnace modules (20) loaded with a workpiece (4) can be moved, and a transfer position are movable, in which a workpiece (4) can be removed from the furnace modules (20).

12. Oven device according to claim 10 or 11, characterized in that the conveyor (44) is arranged such that the oven modules (20) on a continuous path (62, 76, 84) are movable.

13. Oven device according to claim 12, characterized in that the circumferential path (62) is a horizontal circumferential path in a horizontal plane.

14. Oven device according to claim 13, characterized in that the circulating path (76, 84) is a vertically circulating path in a vertical plane.

15. Oven device according to claim 10 or 11, characterized in that the conveying device (44) comprises a rotating device (54), with which the furnace modules (20) are largely in position about a rotation axis, in particular ^¬ special about a vertical axis of rotation, rotatable ,

16. furnace device according to claims 13 or 15, characterized in that the conveying device (44) comprises at least two floors, in which furnace modules (20) are moved.

17. Oven device according to claim 16, characterized in that for at least two floors each have their own circulating horizontal conveyor (60) is present.

Oven device according to one of claims 10 to 17, characterized in that at least two furnace units (48) are present, each comprising a conveyor (44) and an associated module group (46). 19. A plant for the form hardening of workpieces with a furnace device (8), in which workpieces (4) are heatable to a forming temperature, and a forming device (12) in which the heated workpieces (4) are malleable, characterized in that the furnace device (8) A furnace device according to any one of claims 1 to 18.

20. Installation according to claim 19, characterized in that at least two forming devices (12) are present, which workpieces via a common furnace unit (48) or a plurality of furnace units (48) can be fed, wherein a furnace unit (48) each have a conveyor

(44) and an associated module group (46).