METHOD FOR PRODUCING A COMPONENT AND TOOL THEREFOR

Abstract

The invention relates to a method for producing a component having a bottom region, optionally a bottom-body transition region, optionally a body region, optionally a body-flange transition region and optionally a flange region, wherein a semifinished product made of a plastically deformable material is provided, wherein the semifinished product has a longitudinal extent and a transverse extent having a circumferential edge contour having a separating surface, wherein the semifinished product is processed in one or more stages in one or more tools to produce the component. Moreover, the invention relates to a tool for producing a component.

Claims

1. A method for producing a component having a bottom region, wherein a semifinished product made of a plastically deformable material is provided, wherein the semifinished product has a longitudinal extent and a transverse extent having a circumferential edge contour having a parting surface, wherein the semifinished product is processed in at least one stage in at least one tool to produce the component, wherein the parting surface is in contact with the tool at least temporarily one of during or after the processing of the semifinished product to produce the component, and in at least one section.

2. The method as claimed in claim 1, wherein the semifinished product is prepared from a hardenable steel material, which is subjected to heat treatment in at least one region in the form of a shaped blank, wherein, the shaped blank is heated above an A.sub.c1 temperature, formed in at least one stage and hardened, at least in one region, by cooling.

3. The method as claimed in claim 1 wherein the semifinished product is cold-formed to give a preform having a bottom region, a transition region, a body region, wherein at least the geometry of the preform or individual preform regions differ, at least in one region, from the geometry of the component or of individual component regions.

4. The method as claimed in claim 3 wherein the preform has a bottom region, a bottom-body transition region and a body region, the preform is heated in a furnace, to at least A.sub.c1 temperature, the heated preform is placed in an open tool for hardening, said tool being actively cooled and comprising at least one female die and one punch, and the component produced is hardened, at least in one region through contact with the tool by closing the tool, wherein the punch acts to exert pressure, at least in one section on the parting surface of the body region, along the longitudinal extent of the component to be produced.

5. The method as claimed in claim 3 wherein the preform has a bottom region, a bottom-body transition region, a body region, a body-flange transition region and a flange region, the preform is heated in a furnace, to at least A.sub.c1 temperature, the heated preform is placed in an open tool, said tool being actively cooled and comprising at least one female die and one punch, and the sheet-metal component produced is hardened, at least in one region, through contact with the tool by closing the tool, wherein at least the female die and the punch acts to exert pressure, at least in one section, on the parting surface of the flange region along the longitudinal extent of the component to be produced.

6. The method as claimed in claim 5 wherein a punch consisting of a plurality of sub-punches is used, wherein, when the tool is closed, contact is established between a first sub-punch and the bottom region, the bottom-body transition region and the body region in a first step, and contact is established between a second sub-punch and the flange region in a second step.

7. The method as claimed in claim 2 wherein the shaped blank is heated in a furnace, to at least A.sub.c1 temperature, after heating the shaped blank is placed in an open tool, said tool being actively cooled and comprising at least one female die and a punch, the shaped blank being formed in at least one stage by shutting the tool, and the component produced is hardened, at least in one region, through contact with the hardening tool by closing the tool, wherein at least one of the punch and the female die acts to exert pressure, at least in one section, on the parting surface of the body region along the longitudinal extent of the component to be produced.

8. The method as claimed in claim 7 wherein the tool has at least a movable female die region and a leading punch, which, after the placing of the heated shaped blank in the tool, fixes the shaped blank, together with the punch, with a clamping action, at least in the bottom region to be formed, until the tool is closed.

9. The method as claimed in claim 8 wherein the tool has at least one heatable hold-down device, which, after the placing of the heated shaped blank in the tool, is lowered in a spaced manner in order to guide the shaped blank one of before and after the moving together of the movable female die region and the punch.

10. A tool for hardening as part of a process line for producing a component having a bottom region consisting of a semifinished product, which consists of a plastically deformable material, wherein the semifinished product has a longitudinal extent and a transverse extent having a circumferential edge contour having a parting surface, having a female die and having a punch, having means for moving at least one of the punch and the female die, having optional means for cooling the tool wherein the parting surface is in contact with the tool at least temporarily, at least one of during and after the processing of the semifinished product to produce the component.

11. The tool as claimed in claim 10 wherein at least one of the female die and the punch is configured in such a way that, at least in one section it acts to exert pressure on the parting surface of the bottom region along the longitudinal extent of the component to be produced.

12. The tool as claimed in claim 11 wherein at least one of the punch has a shoulder region for acting on the parting surface of the body region, and the female die has a shoulder region.

13. The tool as claimed in claim 12, wherein the tool has at least one heatable hold-down device.

14. The tool as claimed in claim 13, wherein the tool has a substantially vertically movable female die region.

15. The tool as claimed in claim 14, wherein the punch consists of a plurality of sub-punches.

16. The tool as claimed in claim 15, wherein the punch is coupled to a punch holder, wherein the punch is arranged in such a way that it can be moved toward and away from the punch holder in a working direction.

17. The tool as claimed in claim 16, wherein the female die has an outer female die part and an inner female die part, wherein the outer female die part, is horizontally movable.

18. The method as claimed in claim 1 wherein the semifinished product is first of all cold-formed into a preform, the preform is subjected to heat treatment in at least one region, wherein the preform is heated above an A.sub.c1 temperature and is then hardened by cooling, at least in one region.

19. The tool of claim 10, further comprising at least one of a bottom-body transition region, a body region, a body-flange transition region and, a flange region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention is explained in greater detail below with reference to drawings.

[0041] Identical parts are provided with identical reference signs. In the drawings:

[0042] FIG. 1 shows the first steps for indirect hot forming,

[0043] FIG. 2 shows the first steps for direct hot forming,

[0044] FIGS. 3 to 5 show further steps for the production of a flanged sheet-metal component, in particular a hardened component of this kind, by means of indirect hot forming,

[0045] FIGS. 6 to 8 show further steps for the production of a flangeless sheet-metal component, in particular a hardened component of this kind, by means of indirect hot forming,

[0046] FIGS. 9 to 12 show further steps for the production of a flanged sheet-metal component, in particular a hardened component of this kind, by means of direct hot forming,

[0047] FIGS. 13 to 16 show further steps for the production of a flangeless sheet-metal component, in particular a hardened component of this kind, by means of direct hot forming,

[0048] FIGS. 17 and 18 show another embodiment of a tool,

[0049] FIGS. 19 to 23 show further steps for the production of a flanged sheet-metal component, in particular a hardened component of this kind, by means of direct hot forming,

[0050] FIGS. 24 to 28 show further steps for the production of a flanged sheet-metal component, in particular a hardened component of this kind, by means of direct hot forming, and

[0051] FIGS. 29 to 33 show further steps for the production of a flangeless sheet-metal component, in particular a hardened component of this kind, by means of direct hot forming.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] The following explanations show methods and tools for the production of a component, in particular a hardened component or sheet-metal component, wherein, in the simplest embodiment thereof and for the sake of illustration, the sheet-metal component to be produced has a symmetrical cross section along its longitudinal extent. Owing to the resulting symmetry (mirror symmetry on the axis of symmetry S), only partial sections of the right-hand side are shown. Of course, any cross-sectional shapes are conceivable, particularly in combination with cross-sections that vary along the longitudinal extent of the sheet-metal component to be produced and with curvatures in all directions.

[0053] FIGS. 3 to 5 show a method sequence according to one embodiment of the invention. By means of indirect hot forming (FIG. 1), a hardened sheet-metal component (1) is produced, which has a bottom region (1.1), a bottom-body transition region, a body region (1.2), a body-flange transition region, and a flange region (1.3).

[0054] A hardenable steel material is generally unwound from a coil (not illustrated), cut to length and made available to the further process as a blank (step A, FIG. 1). From the blank, which can have a predefined precut, a preform (1′) is produced by means of cold forming, which already has a bottom region (1′.1), a bottom-body transition region, a body region (1′.2), a body-flange transition region, and a predefined flange region (1′.3) (step B, FIG. 1). The blank as a predefined precut blank and/or the preform (1′) can have an addition with a length (L′) which is developed in cross section, at least in some region or regions, and which is longer by between 0.5 to 4 mm, for example, than the developed length (L) of the finished, preferably hardened, sheet-metal component (1). It is possible for the addition to be provided only within the manufacturing process by ironed regions and/or as a material excess or material addition on the semifinished product. In particular, at least the geometry of the preform (1′), in particular of the flange region (1′.3) and/or of the body region (1′.2) deviates, at least in some region or regions, from the geometry of the sheet-metal component (1), in particular of the flange region (1.3) and/or of the body region (1.2). The preform (1′) is heated in a furnace, preferably in a continuous furnace, to at least the A.sub.c1 temperature, in particular fully to the A.sub.c3 temperature (step C, FIG. 1).

[0055] The heated preform (1′) is placed in an open tool (2) for hardening, which is actively cooled by suitable means, e.g. by means of cooling passages (2.X), which are supplied with a cooling fluid and are arranged or integrated in the tool (2), close to the contour surface, and comprises at least one female die (2.1) and one punch (2.2) (FIG. 3). The punch (2.2) consists of a plurality of sub-punches (2.21, 2.22), which are arranged in the working direction relative to one another and are individually controllable or movable, this being symbolized by the arrows.

[0056] Through the (increasing) closure of the tool (2), the preform (1′) is hardened, at least in some region or regions, by contact with the tool (2). The closure of the tool (2) takes place in several steps, wherein, in the first step, a first sub-punch (2.21) is moved into the female die (2.1) and contact is thereby established between the first sub-punch (2.21) and the bottom region (1′.1), the bottom-body transition region and the body region (1′.2) (FIG. 4). Before or after the bottom end position of the first sub-punch (2.21) is reached, a second sub-punch (2.22) is moved into the female die (2.1) in a second step in order to establish contact between the second sub-punch (2.22) and the flange region (1′.3). By virtue of the material addition, for example, there is an oversize in the flange region (1′.3), at least in some region or regions, in particular along the longitudinal orientation of the sheet-metal component (1) to be produced. Moving the second sub-punch (2.22) into the female die (2.1) presses the flange region (1′.3) in the direction of the female die (2.1). During this process, the parting surface (1′.4) of the flange region (1′.3) comes into contact with a shoulder region (2.13) of the female die (2.1), which, owing to further movement of the second sub-punch (2.22) into the female die (2.1), acts to exert pressure, at least in some section or sections, on the parting surface (1′.4) of the flange region (1′.3), in particular along the longitudinal extent of the sheet-metal component (1) to be produced, as a result the pressure is increased further and leads to thickening, at least in some region or regions, in particular along the longitudinal extent of the hardened sheet-metal component (1), in particular in the edge region close to the edge of the flange region (1.3) or in the flange region (1.3) and/or body region (1.2) (FIG. 5). The sheet-metal component (1) produced remains in the closed tool (2) until the desired microstructure has been established. After this, the tool (2) is opened, and the hardened sheet-metal component (1) can be removed.

[0057] In a further example of indirect hot forming, the steps mentioned in connection with FIG. 1 are carried out, although, in contrast to the previous example, a preform (1′) which does not have a flange region and a body-flange transition region is produced.

[0058] The heated preform (1′) having a bottom region (1′.1), a bottom-body transition region and a body region (1′.2) is placed in an open tool (2), which is actively cooled by suitable means, e.g. by means of cooling passages (2.X), which are supplied with a cooling fluid and are arranged or integrated in the tool (2), close to the contour surface, and comprises a female die (2.1) and a punch (2.2) (FIG. 6). The closing of the tool (2) takes place in one step by movement of the punch (2.2) into the female die (2.1) (FIG. 7). By virtue of the material excess which arises or of a deliberate material addition, there is an oversize in the body region (1′.2), at least in some region or regions, in particular along the longitudinal extent of the sheet-metal component (1) to be produced. Before the bottom end position of the punch (2.2) is reached, the parting surface (1′.4) of the body region (1′.2) comes into contact with a shoulder region (2.23) of the punch (2.2), which, owing to further movement of the punch (2.2) into the female die (2.1), acts to exert pressure, at least in some section or sections, on the parting surface (1′.4) of the body region (1′.2), in particular along the longitudinal extent of the sheet-metal component (1) to be produced, as a result the pressure is increased further and leads to thickening, at least in some region or regions, in particular along the longitudinal extent of the hardened sheet-metal component (1), in particular in the edge region close to the edge of the body region (1.2) or in the body region (1.2) itself (FIG. 8). The sheet-metal component (1) produced remains in the closed tool (2) until the desired microstructure has been established. After this, the tool (2) is opened, and the hardened sheet-metal component (1) can be removed. To accommodate the thickening material, a corresponding free space can be provided in the female die and/or punch.

[0059] In another example of direct hot forming, a hardenable steel material is unwound from a coil (not illustrated), cut to length and made available to the further process as a blank, wherein, as a particular preference, the blank corresponds to a shaped blank (step A, FIG. 2). The shaped blank (1′) can have a material addition with a length (L′) which is developed in cross section, at least in some region or regions, and which is longer by between 0.5 and 4 mm, for example, than the developed length (L) of the hardened sheet-metal component (1). The shaped blank (1′) is heated in a furnace, preferably in a continuous furnace, to at least the A.sub.c1 temperature, in particular fully to the A.sub.c3 temperature (step C, FIG. 2).

[0060] The heated preform (1′) is placed in an open tool (2) for hardening, which is actively cooled by suitable means, e.g. by means of cooling passages (2.X), which are supplied with a cooling fluid and are arranged or integrated in the tool (2), close to the contour surface, and comprises at least one female die (2.1), one punch (2.2) and one hold-down device (2.3), which is heatable if required (FIG. 9). The female die (2.1) comprises a female die region (2.11) that can be moved relative to the female die bearing surface, this being symbolized by the arrow.

[0061] Through the (increasing) closure of the tool (2), the shaped blank (1′) is first of all formed and then hardened, at least in some region or regions, by contact with the tool (2). The closure of the tool (2) takes place in several steps, wherein, in the first step, the hold-down device (2.3), which is heated if required, is lowered onto a spacer element (2.4) and held in order to provide supportive guidance for the shaped blank edge during hot forming. The spacer element (2.4) has the effect that only point contacts arise with the hot shaped blank (1′) and can also serve as a positioner for the placement of the hot shaped blank (1′). At the same time or at offset times, the female die region (2.11) and the punch (2.2) or punch region are moved relative to one another until they receive the shaped blank (1′) between them in a clamped manner (FIG. 10). The clamped region corresponds to the bottom region (1.1) to be formed on the sheet-metal component (1) to be produced. The punch (2.2) or punch region and the female die region (2.11) travel together with the clamped shaped blank (1′) into the female die (2.1), and a bottom-body transition region, a body region, a body-flange transition region and a flange region form as inward travel progresses (FIG. 11). Once the bottom region, the bottom-body transition region and substantially the body region have been formed, there remains an oversize in the flange region and/or in the body-flange transition region, at least in some region or regions, in particular along the longitudinal extent of the sheet-metal component (1) to be produced, by virtue of the material addition. Before the bottom end position is reached, the flange region is pushed in the direction of the female die (2.1). During this process, the parting surface (1′.4) of the flange region comes into contact with a shoulder region (2.13) of the female die (2.1), which, owing to further movement of the punch (2.2) into the female die (2.1), acts to exert pressure, at least in some section or sections, on the parting surface (1′.4) of the flange region, in particular along the longitudinal extent of the sheet-metal component (1) to be produced, as a result the pressure is increased further and leads to thickening, at least in some region or regions, in particular along the longitudinal extent of the hardened sheet-metal component (1), in particular in the edge region close to the edge of the flange region or in the flange region and/or body region and/or body-flange transition region (FIG. 12). The sheet-metal component (1) produced remains in the closed tool (2) until the desired microstructure has been established. After this, the hardening tool (2) is opened, and the hardened sheet-metal component (1) can be removed.

[0062] In a further example of direct hot forming, the steps mentioned in connection with FIG. 2 are carried out, although, in contrast to the previous example, a hardened sheet-metal component without a flange region and without a body-flange transition region is produced.

[0063] The heated shaped blank (1′) is placed in an open tool (2) for hardening, which is actively cooled by suitable means, e.g. by means of cooling passages (2.X), which are supplied with a cooling fluid and are arranged or integrated in the tool (2), close to the contour surface, and comprises at least one female die (2.1), one punch (2.2) and one hold-down device (2.3), which is heated if required (FIG. 13). The female die (2.1) comprises a movable female die region (2.11), symbolized by the arrow, and the punch (2.2) is coupled to a punch holder (2.24), wherein the punch (2.2) is arranged in such a way that it can be moved toward and away from the punch holder (2.24) in the working direction. A spring element (2.25) arranged between the punch (2.2) and the punch holder (2.24) holds the punch (2.2) at a distance from the punch holder (2.24).

[0064] Through the closure of the tool (2), the shaped blank (1′) is first of all formed and then hardened, at least in some region or regions, by contact with the tool (2). The closure of the tool (2) takes place in several steps, wherein, in the first step, the hold-down device (2.3), which is heated if required, is lowered onto a spacer element (2.4) and held in order to provide supportive guidance for the shaped blank edge during hot forming. The spacer element (2.4) has the effect that only a few point contacts arise with the hot shaped blank (1′). At the same time or at offset times, the female die region (2.11) and the punch (2.2) or punch region are moved relative to one another until they receive the shaped blank (1′) between them in a clamped manner. The clamped region corresponds to the bottom region (1.1) to be formed on the sheet-metal component (1) to be produced. The punch (2.2) or punch region and the female die region (2.11) travel together with the clamped shaped blank (1′) into the female die (2.1), and a bottom-body transition region and a body region form as inward travel progresses (FIG. 14). Once the bottom region, the bottom-body transition region and substantially the body region close to the bottom have been formed, there remains an oversize in the body region, at least in some region or regions, along the longitudinal orientation of the sheet-metal component (1) to be produced, by virtue of the material addition. Once the bottom end position has been reached, the parting surface (1′.4) of the body region comes into contact with a shoulder region (2.23) of the punch or punch holder (2.24) (FIG. 15). By increasing the pressure on the punch holder (2.24), the force of the spring element (2.25) is overcome, and the punch (2.2) and the punch holder (2.24) approach one another. As a result, the shoulder region (2.23) acts to exert a pressure, at least in some section or sections, on the parting surface (1′.4) of the body region, in particular along the longitudinal extent of the sheet-metal component (1) to be produced, and the further approach between the punch (2.2) and the punch holder (2.24) leads to thickening, at least in some region or regions, in particular along the longitudinal extent of the hardened sheet-metal component (1), in particular in the edge region close to the edge of the body region (1.2) or in the body region (1.2) (FIG. 16). The sheet-metal component (1) produced remains in the closed tool (2) until the desired microstructure has been established. After this, the tool (2) is opened, and the hardened sheet-metal component (1) can be removed.

[0065] FIGS. 17 and 18 illustrate another embodiment of a tool (2) or another procedure which can be used for cold forming and for hot forming, which, in contrast to the tool (2) and the procedure described in or with reference to FIGS. 9 to 12, has a split female die (2.1) comprising two female die parts, an outer female die part (2.121) and an inner female die part (2.122), which can be controllable and movable separately from one another and, if required, individually in a vertical orientation in the shoulder region (2.13). Before a shaped blank is placed in the tool (2), the outer female die part (1.121) is moved horizontally into a parked position, resulting in a certain spacing between the outer and the inner female die part (1.121, 1.122). After a shaped blank has been placed in the open tool (2) and forming has already been set in train by the lowering of the punch (2.2), the outer female die part (1.121), which has previously been moved to a distance from the inner female die part (1.122), enables the edge region close to the edge of the flange region to be transferred unhindered into a position such that, shortly before the bottom end position, the outer female die part (2.121), which is driven by means of wedge-type slides for example, can be driven against the parting surface (1.4′) of the flange region, in particular along the longitudinal extent of the component (1) to be produced (FIG. 17). The increase in the pressure on the parting surface (1′.4) forces the oversize or material excess of the semifinished product into the flange region (FIG. 18) and thereby acts to exert pressure, at least in some section or sections, as a result of which the component (1) receives a dimensionally accurate edge contour. To accommodate the thickening material, a corresponding free space can be provided in the female die and/or punch. After this, the tool (2) is opened, and the component (1) can be removed.

[0066] FIGS. 19 to 23 show a method sequence according to another embodiment of the invention for the production of a flanged sheet-metal component (1), in particular a hardened sheet-metal component of this kind.

[0067] FIGS. 24 to 28 show a method sequence according to another embodiment of the invention for the production of a flanged sheet-metal component (1), in particular a hardened sheet-metal component of this kind, having a body region (1.2) which extends obliquely in contrast to the other illustrative embodiments.

[0068] FIGS. 29 to 33 show a method sequence according to another embodiment of the invention for the production of a flangeless sheet-metal component (1), in particular a hardened sheet-metal component of this kind, having a body region (1.2) which extends obliquely in contrast to the other illustrative embodiments.

[0069] In the sectional illustration of the tool (2) in FIGS. 19 to 33, no cooling passages are illustrated. These are generally required in order to ensure sufficient heat dissipation to harden the sheet-metal component to be produced.

[0070] The invention is not restricted to the above-described embodiments and to the general description. In particular, all the features mentioned in relation to the method and in relation to the tool can be combined with one another. In the simplest embodiment, the component can be a substantially flat design and have only one bottom region and, in particular, can be thickened in the edge region close to the edge. Further embodiments of components having a bottom region, a bottom-body transition region, a body region, optionally a body-bottom transition region and optionally a flange region have been described. In addition to steel, which can be processed either cold or hot, other metals, such as aluminum, magnesium or other materials, e.g. thermoplastics, which can be processed especially in the cold or the hot state, can also be used. The preferably hardened sheet-metal component produced by the method according to the invention is used as a bodywork or chassis component in passenger cars, utility vehicles, commercial vehicles, heavy goods vehicles, special vehicles, buses, omnibuses, agricultural machines, construction machines, with or without an internal combustion engine and/or an electric drive, and trailers. Hardened sheet-metal components produced according to the invention can also be used in vehicle attachments, e.g. in assembled battery cases for electric or hybrid vehicles. Components produced according to the invention can also be used in applications that are not specific to vehicles.