METHOD FOR PRODUCING A COMPONENT FROM DIFFERENT MATERIALS, AND COMPONENT AND USE THEREFOF

Abstract

A method may be used to produce a component that includes at least two different materials. The method may involve providing a hardenable planar or preformed steel sheet or steel profile, completely or partially heating the steel sheet or steel profile to the austenitic temperature, inserting the heated steel sheet or steel profile into a first tool for hot forming and/or press hardening the steel sheet or steel profile to give a completely or partially hardened steel workpiece. In the course of the hot forming and/or press hardening at least one jog is made in the steel sheet or the steel profile. The jog may serve for fastening at least one second material thereto.”

Claims

1.-7. (canceled)

8. A method for producing a component that includes at least two different materials, the method comprising: providing a hardenable planar or preformed steel sheet or steel profile; at least partially heating the steel sheet or the steel profile to an austenitic temperature; inserting the heated steel sheet or the heated steel profile into a first tool for at least one of hot forming or press hardening the steel sheet or the steel profile to produce a first steel workpiece that is at least partially hardened, wherein during the at least one of hot forming or press hardening a jog is made in the steel sheet or the steel profile, wherein the jog serves for fastening a second material to the first steel workpiece; and fastening the second material to the first steel workpiece, wherein the second material comprises plastic and at least partially reinforces the first steel workpiece.

9. The method of claim 8 wherein the jog is hardened.

10. The method of claim 8 wherein the jog is not hardened.

11. The method of claim 8 further comprising: passing the jog through the second material; and turning a projecting part of the jog for a purpose of being received with positive engagement.

12. The method of claim 8 further comprising inserting the first steel workpiece into a second tool and injecting liquid plastic around and/or behind the first steel workpiece at least in a region of the jog.

13. The method of claim 12 wherein the second tool is an injection mold.

14. The method of claim 8 wherein a roller hearth furnace is used to at least partially heat the steel sheet or the steel profile.

15. The method of claim 8 wherein the steel sheet or the steel profile is completely austenitized.

16. The method of claim 8 wherein the first tool comprises a punch die.

17. A component including at least two different materials, the component comprising: a steel workpiece that is at least partially hardened, the steel workpiece comprising a jog; and a second material fastened to the steel workpiece by way of the jog, wherein the second material comprises plastic and at least partially reinforces the steel workpiece.

18. The component of claim 17 wherein the steel workpiece and the second material are configured as a crash-relevant component of a vehicle.

19. The component of claim 18 wherein the steel workpiece and the second material are configured as an A pillar, a B pillar, a C pillar, a D pillar, a side member, or a cross member of the vehicle.

20. The component of claim 17 wherein the steel workpiece and the second material are configured as an A pillar, a B pillar, a C pillar, a D pillar, a side member, or a cross member of a vehicle.

Description

[0015] The invention will be explained in more detail below with reference to a drawing that illustrates exemplary embodiments. Like parts are provided with like reference numerals. In the drawing:

[0016] FIG. 1 shows an embodiment of a method according to the invention,

[0017] FIG. 2a shows a perspective illustration of an embodiment of a component according to the invention, in front view,

[0018] FIG. 2b shows a first embodiment of a partial region of the component shown in FIG. 2a, in rear view, and

[0019] FIG. 2c shows a second embodiment of a partial region of the component shown in FIG. 2a, in rear view.

[0020] FIG. 1 illustrates an embodiment, in particular a step-by-step sequence of a method according to the invention. Planar hardenable steel sheets 1 are provided. As an alternative, and not illustrated here, it is also possible to provide already preformed that may comprise almost the final geometry of the steel workpiece to be produced, or may take the form of closed steel profiles. The steel sheets 1 may also be cut from a coil to an appropriate length before they are provided and, if cutting is not part of the hot forming process, may be trimmed to the appropriate dimensions or as an alternative cut by hard laser cutting of the completely or partially hardened steel workpiece (not illustrated here in any of the drawings). In the next step, the steel sheet 1 is heated to austenitic temperature, for example in a roller hearth furnace 2. Other heating devices are also conceivably suitable but are not illustrated here. In the example shown, the steel sheet 1 is completely austenitized. As an alternative and not illustrated here, it is also possible to austenitize only partially a region of the steel sheet.

[0021] After the heating, and after it has exited from the roller hearth furnace 2, the steel sheet 1 is removed from the roller conveyor 2′ by way of suitable devices (symbolized here by an arrow) and transferred to a first tool 3, and inserted therein. The tool 3 includes an upper die 4 that takes the form of a punch and a lower die 5 that takes the form of a cavity. If necessary, and not illustrated here, it is also possible for hold-down devices to be provided. Provided in the cavity 5, at 7, is at least one projection or elevated portion, wherein there is provided on the opposite side, in the punch 4, at 6, at least one notch or recess. Once the austenitized steel sheet 1 has been inserted into the tool 3, the two die halves 4, 5 are brought together, typically with the lower die 5 being constructed to be stationary and the upper die 4 being movable in relation to the lower die 5, symbolized by the double-headed arrow that is illustrated perpendicular thereto. Bringing the die halves together has the effect first that the hot steel sheet is shaped by hot forming and, as a result of the typically active cooling by integrated cooling circuits (not illustrated here) within the die halves 4, 5, the still hot steel sheet is cooled, with the heat extraction rate being set such that, once the bottom position is reached, press hardening ensures that the austenitic microstructure is converted into a preferably martensitic microstructure. Before the bottom position is reached, at which point the hardening process is not yet complete and the steel sheet, which is still in the hot condition, is relatively easy to work, the projection 7 in the cavity 5, in conjunction with the notch 6 in the punch 4, makes at least one jog 9 in the steel workpiece 8 as a result of further relative movement between the die halves 4, 5. Depending on the application or fastening of the plastics material thereto, the jog 9 may be hardened, in which case the projection 7 and the notch 6 are cooled or heat is extracted from the jog 9 (not illustrated here), or the jog 9 is not hardened, in which case for example the projection 7 and the notch 6 are insulated or subject to temperature control (not illustrated here).

[0022] Depending on the component or the use thereof, it is possible to perform complete or partial hardening, wherein, in the case of partial hardening, the regions in the steel workpiece that are not to be converted to a completely martensitic microstructure are acted upon by heat, preferably during the hot forming and/or press hardening, by heating elements (not illustrated here) that are integrated in the tool.

[0023] If the jog 9 is made and hardened in the course of the hot forming and/or press hardening projecting at an angle of in particular less than 90°, preferably less than 60° and particularly preferably less than 45°, from the plane of the steel workpiece 8, wherein an unhardened jog 9 is also conceivable, then in a further step a plastics material is fastened on, wherein the completely or partially hardened steel workpiece 8 is inserted into a second tool, which is an injection mold 10 and in turn includes a lower mold and an upper mold 11, and liquid plastics material that is conveyed or injected through lines 12 within the upper mold 11 is injected around and/or behind the steel workpiece 8, at least in the region of the jog 9. The in particular angled orientation of the jog provides a type of undercut which, in particular after curing of the plastics material, preferably the fiber-reinforced plastics material, ensures a permanent fastening to the steel material and provides a component 15 that is at least partially stronger, wherein the cured plastics material 18 completely covers the jog.

[0024] As an alternative, a plastics material that has already been preformed and preferably takes the form of a fiber-reinforced, precisely fitting plastics molding 13 is provided in order to be fastened to the steel material 8 and to make it at least partially stronger. Fastening to the plastics molding 13, which is at least partially arranged in the region of the jog 9, is performed by devices that are not illustrated here, wherein the jog 9 is passed through the plastics molding 13, which preferably comprises an opening or a slot 14 at the appropriate location (fastening location). The length of the jog 9 is selected such that, once the two materials 16 have been brought together, at least part of the jog 9′ projects out and in a further step is turned through 90° again to be parallel to, in particular making contact with, the plastics molding 13 for a positively engaging fastening thereto (cold).

[0025] In FIGS. 2a to 2c, examples of a component in the form of a B pillar are shown, in particular produced by a first and a second method according to the invention. The hot forming and/or press hardening of planar or preformed steel sheets to give steel workpieces has already been sufficiently described.

[0026] In FIG. 2a, in a perspective illustration of a steel workpiece 8 in the form of a B pillar 17, jogs 9 are shown that are made in pairs as prongs in the form of isosceles triangles, wherein the tips of the triangles are oriented into the plane of the drawing (not visible). As an alternative, not illustrated here, the jogs may also take a tab-like, collar-like and/or ring-shaped form. The location of the reinforcement of a crash-relevant component may preferably be determined by simulation. Taking the example of the B pillar, the upper third of the component 17 is to be made stronger, as a result of which intrusion in the direction of the passenger compartment and, associated herewith, the risk of injury to the upper body/head of the vehicle occupants on the driver and passenger side in the event of a side impact can be reduced to a minimum. As regards the appearance of the geometry of the kink, it is particularly preferred if no geometric notching effect is produced. The geometry of the jog may also be determined in the course of a simulation.

[0027] FIG. 2b shows a partial region of FIG. 2a in rear view. The reinforcement by means of plastics material, preferably by means of fiber-reinforced plastics material, is performed in the course of injection molding behind and/or around the part, wherein the cured plastics material 18 completely covers the jogs (cf. FIG. 1, component 15).

[0028] As an alternative, in FIG. 2c, as a partial region of FIG. 2a, there is illustrated in rear view the fastening to a plastics molding 13, wherein the length of the jog 9, which was not hardened in the course of hot forming and/or press hardening, is dimensioned such that, after the two materials have been brought together, at least one projecting part of the jog 9′ is turned in a further step to be parallel to and in contact with the plastics molding 13 for a positively engaging fastening thereto (cf. FIG. 1, component 16).

[0029] The invention may be applied to any crash-relevant components and is not restricted to the exemplary embodiment.

LIST OF REFERENCE NUMERALS

[0030] 1 Steel sheet [0031] 2 Roller hearth furnace [0032] 2′ Roller conveyor [0033] 3 Tool [0034] 4 Upper die/punch [0035] 5 Lower die/die block [0036] 6 Notch/recess [0037] 7 Projection/elevated portion [0038] 8 Steel workpiece [0039] 9 Jog [0040] 9′ Projecting part of the jog [0041] 10 Injection mold [0042] 11 Upper mold [0043] 12 Lines [0044] 13 Plastics molding [0045] 14 Opening/slot [0046] 15 Component [0047] 16 Component [0048] 17 B pillar [0049] 18 Cured plastics material