METHOD FOR PRODUCING A MOTOR VEHICLE COMPONENT BY HOT-FORMING WITH INTEGRATED CUT

Abstract

A method of making a motor vehicle component by hot-forming, hot-cutting, and press-hardening a plate made of a hardenable steel sheet alloy, heating to a temperature greater than Ac1, inserting in a combined forming and cutting tool, fixing the inserted plate in the forming and cutting tool using a stamp which is arranged in the inner region of the tool, at least partially circumferential edge cutting before beginning the forming operation or during a time period of up to 50% of the forming progression and/or at least 20% of the press stroke prior to the bottom dead center position, and hot-forming in a press stroke with the edge cut and optional press-hardening.

Claims

1-10. (canceled)

11. A method of making a motor vehicle component, the method comprising: heating a plate comprising a hardenable steel sheet alloy to a temperature greater than an Ac1 temperature or an Ac3 temperature of the steel alloy; inserting the heated plate in a combined forming-and-cutting tool; fixing the inserted plate in the forming-and-cutting tool using a stamp arranged in the forming-and-cutting tool; and performing, in a single press stroke of the forming-and-cutting tool, hot-cutting, hot-forming, and press-hardening of the fixed plate to obtain the motor vehicle component, wherein the hot-cutting comprises cutting at least partially a circumferential edge of the fixed plate before beginning the hot-forming, or during the hot-forming, in at least one of a time period of up to 50% of progression of the hot-forming, or a time period of greater than 20% of the press stroke prior to a bottom dead center position of the forming-and-cutting tool.

12. The method according to claim 11, wherein the cutting comprises cutting the entire circumferential edge of the fixed plate.

13. The method according to claim 11, wherein the cutting severs a wall thickness of the plate.

14. The method according to claim 11, wherein the motor vehicle component is U-shaped or hat-shaped in cross-section.

15. The method according to claim 11, wherein the cutting is performed at from 550? to 750? C.

16. The method according to claim 11, wherein, upon completion of the cutting, the plate to be hot-formed has been completely drawn into an interior of the forming-and-cutting tool.

17. The method according to claim 11, wherein the plate is a tailor welded blank which has at least two regions with at least one of (i) mutually different wall thicknesses, or (ii) mutually different steel alloys.

18. The method according to claim 11, wherein the cutting is completed at at least 20 mm before the press stroke reaching the bottom dead center position of the forming-and-cutting tool.

19. The method according to claim 11, wherein, in the fixing, the stamp presses the plate to a lower molding jaw of the forming-and-cutting tool.

20. The method according to claim 11, wherein the stamp and tool components of the forming-and-cutting tool in contact with the plate undergo active cooling during the press-hardening.

21. The method according to claim 11, wherein, in the heating, the plate is heated to a temperature greater than 500? C.

22. The method according to claim 11, wherein at least one of the Ac1 temperature is greater than 700? C., or the Ac3 temperature is greater than 900? C.

23. The method according to claim 11, wherein the cutting is completed before beginning the hot-forming.

24. The method according to claim 11, wherein the cutting is performed and completed during the hot-forming, in a time period of less than 50% of the progression of the hot-forming.

25. The method according to claim 11, wherein the cutting is performed and completed during the hot-forming, in a time period of less than 30% of the progression of the hot-forming.

26. The method according to claim 11, wherein the cutting is performed and completed during the hot-forming, in a time period of less than 20% of the progression of the hot-forming.

27. The method according to claim 11, wherein the cutting is performed and completed during the hot-forming, in a time period of greater than 30% of the press stroke prior to the bottom dead center position of the forming-and-cutting tool.

28. The method according to claim 11, wherein the cutting is completed at at least 30 mm before the press stroke reaching the bottom dead center position of the forming-and-cutting tool.

29. The method according to claim 11, wherein the cutting is completed at at least 100 mm before the press stroke reaching the bottom dead center position of the forming-and-cutting tool.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other advantages, features, properties, aspects of the present disclosure are set out in the following description.

[0034] They provide a simpler understanding of the disclosure. In the figures:

[0035] FIGS. 1A-1C show a forming and cutting tool according to an embodiment of the disclosure,

[0036] FIGS. 2A-2C show modifications with respect to

[0037] FIGS. 1A-1C according to an embodiment of the disclosure,

[0038] FIGS. 3A-3D show the production of a motor vehicle component 13 as a hat-shaped component according to an embodiment of the disclosure,

[0039] FIG. 4A and FIG. 4B show two prefabricated plate regions according to an embodiment of the disclosure.

DETAILED DESCRIPTION

[0040] In the Figures, the same reference numerals are used for identical and similar components, even if a repeated listing is omitted for reasons of simplicity.

[0041] FIGS. 1A-1C show a forming and cutting tool 1 according to the disclosure. The forming and cutting tool 1 has to this end an upper tool 2 and a lower tool 3. In the upper tool 2 itself there is arranged a preceding stamp 4 which clamps a plate 6 which is placed on a lower molding jaw 5 of the lower tool 3 thereon. The preceding stamp 4 has been previously lowered. The plate 6 is fixed in position and no longer is able to be displaced in a horizontal direction H. On an upper molding jaw 7, which is a component of the upper tool 2, and a lower metal sheet holder 8, which is a component of the lower tool 3, correspondingly opposing cutting edges 9 are now arranged.

[0042] By further lowering, illustrated in FIG. 1B, the upper molding jaw 5, an edge cut 10 is carried out. The edge cut 10 corresponds in this instance to the subsequent externally circumferential component edge 11, illustrated in FIG. 1C.

[0043] At the time of FIG. 1B, the forming operation itself has not yet begun. However, the edge cut 10 has been carried out completely. By lowering the upper molding jaw 7 further, the metal sheet holder 8 is lowered relative to the lower molding jaw 5. According to FIG. 1C, the forming operation is then carried out in a molding hollow space 12 which is produced. The forming operation is illustrated in the completed state and results in a flange-free motor vehicle component 13 which is U-shaped in cross section at least over portions of the length. The motor vehicle component 13 is produced from the plate 6 which is intended to be formed. The plate 6 has to this end been drawn into an interior of the forming tool or into an interior of the molding hollow space 12.

[0044] FIG. 1A shows cooling channels 19 which are able to be provided to cool all the tool components which are in contact with the formed plate in order to carry out the press-hardening. The cooling channels 19 are not shown in the other FIG. 1B-FIG. 4B but are provided on the tool.

[0045] FIGS. 2A-2C show a modification with respect to FIGS. 1A-1C. Also in this instance, the edge cut 10 is carried out completely before the beginning of the forming operation. In contrast to FIG. 1C, however, no motor vehicle component 13 which is U-shaped in cross section is produced here, but instead according to FIG. 2C a motor vehicle component 13 which is hat-shaped in cross section. Outwardly protruding flanges 14 protrude in the horizontal direction H. To this end, the lower metal sheet holder 8 is constructed to be wider and also serves to form a molding hollow space 12 when the upper tool 2 has been lowered completely at the bottom dead center position.

[0046] FIGS. 3A-3D show the production of a motor vehicle component 13 as a hat-shaped component similarly to FIG. 2C. In this instance, however, the edge cut 10 is carried out only at a later time, approximately at a time at which at least 20 mm still has to be travelled before reaching the bottom dead center position of the forming tool on the path in the press stroke direction 15. Thus, also in this instance according to FIG. 3B, the plate 6 which has been positioned as a result of the preceding stamp 4 is fixed in position on the lower molding jaw. However, the forming operation has already begun according to FIG. 3B. The cutting tools or the opposing cutting edges 9 then carry out the cutting operation according to FIG. 3C. In this instance, the forming operation has then progressed, for example, by up to 20% or the forming tool has been lowered in the press stroke direction 15 by approximately 20% of the path of the press stroke which is intended to be travelled. The edge cut 10 is, however, at this time already completely terminated so that according to FIG. 3D, when the upper molding jaw has been lowered further and formed together with the lower metal sheet holder 8, the motor vehicle component 13 with flanges 14 which protrude outward in a horizontal direction H is then produced in the molding hollow space 12.

[0047] FIG. 4A and FIG. 4B again shows two prefabricated plate blanks. In the case of FIG. 4A, a tailor welded blank. There are two plate regions 6a and 6b with a different wall thickness. The plate regions 6a and 6b have an offset 16 with respect to each other. As a result of the circumferential edge cut 10, this offset 16 is able to be disregarded since a circumferential edge which is not illustrated in greater detail in FIG. 4A is subsequently cut once again during the method according to the disclosure and no ultimate edge cut 10 or the like would have to be carried out.

[0048] In the case of FIG. 4B, a plate 6 is also shown as a tailor welded blank. A weld seam 17 which connects the two plate regions 6a and 6b has a lateral overhanging weld seam overhang 18. In the case of the circumferential edge cut 10, this weld seam overhang 18 is also cut away.

[0049] The foregoing description of some embodiments of the disclosure has been presented for purposes of illustration and description. The description is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, and modifications and variations are possible in light of the above teachings. The specifically described embodiments explain the principles and practical applications to enable one ordinarily skilled in the art to utilize various embodiments and with various modifications as are suited to the particular use contemplated. Various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the disclosure.