VEHICLE FLOOR AND CORRESPONDING PRODUCTION METHOD

Abstract

A hot stamping vehicle floor (1) for a vehicle frame (100) includes a main floor panel (2) stamped out from at least one sheet metal blank. The floor further includes at least one sheet metal reinforcing patch (4), arranged on the main floor panel (2), overlapping the main floor panel (2). The reinforcing patch (4) is more ductile than the main floor panel (2). The at least one reinforcing patch (4) is joined to at least one area (6) of the main floor panel (2) conceived to withstand compressive crash forces in case of a crash situation of the vehicle and the main floor panel (2) and the at least one reinforcing patch (4) are joined to each other before said vehicle floor (1) is stamped out. The invention also refers to a method for producing the vehicle floor.

Claims

1. A hot stamping vehicle floor (1) for a vehicle frame (100) comprising: [a] a main floor panel (2) stamped out from at least one sheet metal blank, characterized in that [b] said main floor panel (2) is made from one single sheet metal blank, the vehicle floor (1) further comprising [c] at least one sheet metal reinforcing patch (4), arranged on said main floor panel (2), overlapping said main floor panel (2), [d] said at least one reinforcing patch (4) being more ductile than said main floor panel (2), [e] said at least one reinforcing patch (4) being joined to at least one area (6) of said main floor panel (2), said at least one area (6) being conceived to withstand compressive crash forces in case of a crash situation of said vehicle and [f] said main floor panel (2) and said at least one reinforcing patch (4) being joined to each other before said vehicle floor (1) is stamped out.

2. The vehicle floor (1) of claim 1, characterized in that said main floor panel (2) is made from a press hardening steel and said reinforcing patch (4) is made from non-hardenable steel.

3. The vehicle floor (1) according to claim 1 or 2, characterized in that said main floor panel (2) comprises at least one reinforcing beam directly stamped out from said sheet metal blank and in that said at least one reinforcing patch (4) is arranged and joined to said at least one reinforcing beam of said vehicle floor (1).

4. The vehicle floor (1) according to any of claims 1 to 3, characterized in that said at least one reinforcing patch (4) is between 10% and 80% more ductile than said main floor panel (2) and preferably between 25% and 70%.

5. The vehicle floor (1) according to any of claims 1 to 4, characterized in that said main floor panel (2) and said reinforcing patch (4) have a thickness between 0.5 and 8 mm, preferably between 0.5 and 6 mm, more preferably between 0.5 and 3 mm and especially preferably between 0.8 a 1.5 mm.

6. The vehicle floor (1) according to claim 5, characterized in that said main floor panel (2) and said reinforcing patch (4) have the same thickness.

7. The vehicle floor (1) according to any of claims 1 to 6, characterized in that said main floor panel (2) and said reinforcing patch (4) are zinc coated.

8. The vehicle floor (1) according to any of claims 1 to 7, characterized in that said vehicle floor (1) defines a longitudinal direction (L) corresponding to the driving direction and a perpendicular direction (P) and in that said at least one reinforcing patch extends in said perpendicular direction (P).

9. The vehicle floor (1) according to any of claims 1 to 8, characterized in that said main floor panel (2) and said at least one reinforcing patch (4) are joined together by one or more methods of the group consisting of resistance spot welding, standard laser welding, remote laser welding, resistance seam welding (RSEW), gas metal arc welding and laser and arc hybrid welding.

10. The vehicle floor (1) according to any of claims 1 to 9, characterized in that said at least one sheet metal blank for producing said main floor panel (2) has a tensile strength between 1,400 MPa and 2,000 MPa, and said at least one sheet metal reinforcing patch (4) has a tensile strength between 500 and 1,000 MPa.

11. A method for producing a hot stamping vehicle floor (1) for a vehicle frame (100) comprising the step of: [a] hot stamping at least one sheet metal blank for stamping out a main floor panel (2), characterized in that [b] said main floor panel (2) is made from one single sheet metal blank, and in that before said hot stamping step, the method further comprises the steps of: [c] arranging at least one reinforcing patch (4) onto said sheet metal blank, overlapping said sheet metal blank in at least one area (6) of said vehicle floor (1) conceived to withstand compressive crash forces in case of a crash situation, said at least one reinforcing patch (4) being more ductile than said main floor panel (2), [d] joining said at least one reinforcing patch (4) and said sheet metal blank.

12. The method according to claim 11, characterized in that said joining step is carried out by one or more methods of the group consisting of resistance spot welding, standard laser welding, remote laser welding, resistance seam welding (RSEW), gas metal arc welding and laser and arc hybrid welding.

13. The method according to claim 11 or 12, characterized in that said main floor panel (2) is made from a press hardening steel and said reinforcing patch (4) is made from non-hardenable steel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Further advantages and features of the invention will become apparent from the following description, in which, without any limiting character, preferred embodiments of the invention are disclosed, with reference to the accompanying drawings in which:

[0061] FIG. 1, a perspective view of a vehicle floor according to the state of the art.

[0062] FIG. 2, a perspective view of a vehicle floor according to the invention.

[0063] FIG. 3, a side view of the vehicle floor of FIG. 2.

[0064] FIG. 4, a top plan view of the vehicle floor of FIG. 2 showing the reinforcing patches arranged on the reinforcing beams.

[0065] FIG. 5, a vehicle frame including the floor according to the invention.

[0066] FIG. 6, a detail view of the vehicle frame of FIG. 5 in case of a side crash situation.

[0067] FIG. 7 a numerical simulation of the area shown in FIG. 6 of the vehicle floor of FIG. 2 in the crash situation.

[0068] FIG. 8, a detail view of a vehicle floor according to the invention, in which the floor panel and the reinforcing patches are spot welded.

[0069] FIG. 9, a detail view of a vehicle floor according to the invention, in which the floor panel and the reinforcing patches are laser welded.

[0070] FIG. 10, a diagrammatical representation of a first embodiment of the method according to the invention.

DETAILED DESCRIPTION

[0071] FIG. 1 shows a vehicle floor 200 of the state of the art. This vehicle floor of the state of the art comprises a plurality of sheet metal parts, including front panels 202, cross beams 204, longitudinal beams 206, beam reinforcements 208, rear panels 210, middle panel 212 and others. This vehicle floor 200 is made up from 16 independent stamping sheet metal parts in total. These 16 parts must be formed independently and later must be correspondingly joined by any suitable welding process, such spot welding, laser welding or the like. Once finished, the vehicle floor 30 has a weight of more than 30 kg.

[0072] In order to solve the problem of proposing a hot stamping vehicle floor for a vehicle frame which is easier to produce and that is lighter than the vehicle floors of the state of the art, the invention foresees as a hot stamping vehicle floor 1 for a vehicle frame 100 comprising a main floor panel 2 stamped out from at least one sheet metal blank of 1 mm thickness, but is especially preferred that it is made from one single sheet metal blank. Preferably said main floor panel 2 is made from a hot-formed steel.

[0073] As it is apparent from FIGS. 3 and 4 said vehicle floor 1 defines a longitudinal direction L corresponding to the driving direction and a perpendicular direction P and in that said at least one reinforcing patch extends in said perpendicular direction P.

[0074] In the floor of FIGS. 2 to 7, in order to solve the problem of the invention, the vehicle floor 2, further comprises two sheet metal reinforcing patches 4, arranged on the main floor panel 2 overlapping the main floor panel 2. Preferably. reinforcing patches 4 are made from a hot-formed sheet steel of 1 mm of thickness.

[0075] The two reinforcing patches 4 more ductile than the main floor panel 2. In particular, the reinforcing patches 4 are between 10% and 80% more ductile than the main floor panel 2 and preferably between 25% and 70%. The main floor panel 2 has a tensile strength between 1,400 MPa and 2,000 MPa, and the sheet metal reinforcing patch 4 has a tensile strength between 500 and 1,000 MPa.

[0076] Materials fulfilling such conditions are, for example hot-formed grades. The floor panel 2 can be made of a steel for hot stamping, such as the Usibor® 2000 or 1500 of the company Arcelor Mittal, while the reinforcement patches 4 can be made of a steel for hot stamping such as the Ductibor® 450, 500 or 1000 of the same company indicated before.

[0077] It is especially preferable that both the main floor panel 2 and the reinforcing patches 4 are zinc coated.

[0078] The reinforcing patches 4 are joined to two areas 6 of the main floor panel 2 conceived to withstand compressive crash forces in case of a crash situation of the vehicle. In this case, the areas 6 of overlapping concerned correspond to the cross members 12 on to which the seats are attached. From FIG. 7, it is apparent that in this case the whole cross member of the main floor panel 2 is covered with a reinforcing patch 4 due to constructive requirements. However, when a side crash situation takes place, the points affected with the highest compression peaks are the side edges 12 of the vehicle floor which are subject to the highest deformation.

[0079] Both the main floor panel 2 and the two reinforcing patches 4 are joined to each other before the vehicle floor 1 is stamped out by any suitable welding technique such as one or more methods of the group consisting of resistance spot welding, standard laser welding, remote laser welding, resistance seam welding (RSEW), gas metal arc welding and laser and arc hybrid welding.

[0080] FIG. 8 shows the embodiment in which the floor panel 2 and the reinforcing patches 4 are spot welded before being stamped out with a plurality of welding spots 8. Instead, in the embodiment of FIG. 9, the floor panel 2 and the reinforcing patches 4 are joined by way of laser seams 10 obtained by laser welding.

[0081] Also, as already explained the main floor panel 2 comprises two reinforcing beams for the seat attachment directly stamped out from the sheet metal blank corresponding to the cross members for attaching the vehicle seats. The reinforcing patches 4 are arranged and joined to the reinforcing cross beams of the vehicle floor 1.

[0082] Therefore, once the main floor panel 2 and the reinforcement patches 4 are joined a hot stamping step takes place for forming the vehicle floor 1. In other words, in one simple hot-stamping stroke the vehicle floor 1 can be produced.

[0083] Comparatively to the vehicle floor of FIG. 1, the embodiment shown in FIGS. 2 to 5, comprises only 3 parts, and one single forming tool, compared to the 16 parts individually produced of the floor of the state of the art.

[0084] For example, thanks to this design already described, about a 20% of the weight is reduced in comparison to the floor of FIG. 1. However, even higher weight reductions are achievable depending on the floor design. Additionally, although the parts reduction, the vehicle floor withstands satisfactorily crash situations as the one shown in FIGS. 6 and 7.

[0085] Finally, FIG. 10 shows an embodiment of the method according to the invention.

[0086] Firstly, from left to right in FIG. 10, a sheet metal blank of hot stamping steel is provided for forming the main floor panel 2. Two reinforcing patches 4 of non-hardenable steel are arranged onto the sheet metal blank, overlapping the sheet metal blank in the areas 6 of the vehicle floor 1 conceived to withstand compressive crash forces in case of a crash situation.

[0087] Next, these two reinforcing patches 4 are welded together. In this embodiment, the welding is carried out by spot welding, but as already explained, other welding methods are also possible.

[0088] Once the three blanks are joined together to form one single final blanc 18, they are introduced in the furnace 14 and they are heated up to about 900° C.

[0089] Finally, the heated final blanc 18 is introduced in the press hardening die for hot stamping the sheet metal final blank 18 for stamping out the main floor panel 2. At the right side of the FIG. 10 it is apparent the overlapping of the two reinforcing patches 4 with the main floor panel 2 in the cross beam area 20.

[0090] The one-piece floor assembly provides for weight, parts, and welding reduction. The only problem in a conventional fully hardened solution is the high risk of rupture of the fully martensitic material in crash tests. However, this risk is minimized by the addition of the ductile material patches that improve performance and avoids cracks of the fully hardened main floor panel 2.

[0091] While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.