B PILLAR

Abstract

A B pillar of a motor vehicle with a base region and a bead region; in the base region, there is a contact region with a connecting region for connecting the B pillar to a rocker panel; over the span of its height from a base edge to a B pillar head, the B pillar has hard and soft regions, wherein the B pillar has a soft region, which extends from a contact region of the B pillar with the rocker panel to the B pillar head and in this case, extends for at least 100 mm.

Claims

1. A B pillar of a Motor vehicle with, comprising: a base region; a head region; and a contact region in the base region with a connecting region for connecting the B pillar to a rocker panel; over a span of its height from a base edge to a B pillar head, the B pillar has hard and soft regions, wherein the B pillar has a soft region, which extends from a contact region of the B pillar with the rocker panel 2 to the B pillar head for a distance of at least 100 mm.

2. The B pillar according to claim 1, wherein the soft region extends from an upper contact region of the B pillar with the rocker panel to the B pillar head.

3. The B pillar according to claim 1, wherein the soft region extends beyond a fold line between the contact region and a B pillar outside and into the contact region.

4. The B pillar according to claim 2, wherein in the contact region, at least one connecting region, in which the joining points with the rocker panel are positioned, is embodied as hard.

5. The B pillar according to claim 1, wherein the B pillar is hardened above the soft region.

6. The B pillar according to claim 1, wherein the hard regions have a tensile strength >1,400 N/mm.sup.2 and the soft regions have a tensile strength <850 N/mm.sup.2.

7. The B pillar according to claim 1, wherein a second soft region below the connecting region of the B pillar with the rocker panel extends to the B pillar base region.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0018] The invention will be explained by way of example below based on the drawings. In the drawings:

[0019] FIG. 1: shows a schematic view of a first embodiment of the invention;

[0020] FIG. 2: shows a schematic view of another embodiment of the invention;

[0021] FIG. 3: shows a side view of a B pillar;

[0022] FIG. 4: shows a schematic, partially sectional view of a B pillar on a rocker panel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] A B pillar 1 is for placement between a rocker panel 2 (shown in FIGS. 1 and 2) and a roof region of a motor vehicle (not shown). To this end, the base 3 of the B pillar 1 has a rocker panel attachment 4 or connecting tab 4, which is usually composed of a flat region of sheet metal, but whose contour can be adapted to the outer contour of a rocker panel 2 and which serves as a contact region K between the B pillar base 3 and the rocker panel 2.

[0024] From the base 3 or connecting tab 4, the B pillar extends upward like a box and is curved toward a vehicle interior.

[0025] The box-like, curved region is embodied as U-shaped in cross-section, with a region that is open toward the vehicle interior, a B pillar outside 5, and two flanks 6 extending away from the B pillar outside 5. In a connecting region to a roof region, the head 7 of the B pillar 1, there is a connecting tab 8 for connecting to a roof structure of the vehicle, the connecting tab 8 having connecting pieces 9 that point toward the vehicle interior.

[0026] The B pillar 1 is usually placed on, a rocker panel 2 by means of spot welds 10 in the contact region K between the B pillar and the rocker panel, i.e. the region of the connecting tab 4, which connects the connecting tab 4 to the outside of the rocker panel 2.

[0027] The connection of the rocker panel to the B pillar is often not carried out uniformly over the entire contact region K, but is instead particularly situated in the connecting region A between the B pillar base and the rocker panel, i.e. the connecting region A in which for example the spot welds are located—which is a subregion A of the contact region K.

[0028] A B pillar 1 according to the invention is produced using the so-called press hardening method in which a flat blank composed of a hardenable sheet steel material is cold-formed into a complete preform, then heated to a temperature above Ac.sub.3 in order to austenitize the structure of the steel material, and then quenched in a forming tool and thus hardened. Alternatively, a flat sheet metal blank made of a hardenable steel material is heated to a temperature above Ac.sub.3 and thus austenitized and is then shaped and, hardened in one step.

[0029] According to the invention, however, the entire blank is not hardened; instead, soft regions are formed in the region of the base of the blank.

[0030] In order to ensure an optimal introduction of force and an optimal flow of force and frictional connection between the B pillar 1 and the rocker panel 2, at least the region of the rocker panel attachment 4 in which the spot welds 10 are located must be embodied as hard, i.e. in this case, quench hardening must be performed (FIG. 1), so that at least in the connecting region A, i.e. in the region in which the B pillar is connected in particular welded—to the rocker panel 2, a hardened strip H (FIG. 1) is formed. Below this strip down to a base edge 11 of the B pillar 1, a soft region W.sub.2 can be provided; above the strip H and above a folding edge 12 between the contact region K and the outside 5, a second soft region W.sub.1 is provided. Above the connecting region is the upper contact region oK. This is a subregion of the entire contact region K.

[0031] The region W.sub.1, W must have a minimum width of 100 mm, thus enabling the B pillar to fold in an energy-absorbing way in the event of a crash.

[0032] The hardened region of the contact region K, however, can also include the entire height of the contact region K between the edge 11 and the fold 12, in particular the region of the B pillar that is situated in the connecting region A of the rocker panel 2.

[0033] At least the connecting region A of the B pillar to the rocker panel, however, must have a hardened structure.

[0034] The hard region H (FIG. 2), however, must under no circumstances protrude beyond the rocker panel region, i.e. beyond the folding edge 12, for example, since otherwise, the folding of the B pillar is also not assured. In this case as well, the region W must be at least 100 mm wide.

[0035] A sufficiently large number of options for producing the soft regions are available to the person skilled in the art. In particular, the soft region can be produced by not heating the sheet to the austenitization temperature in this region or, if it has been heated to above the austenitization temperature, by cooling it in this region at a cooling speed that lies below the critical hardening speed, or these regions are tempered again after the quench hardening.

[0036] As defined by the invention, the term “hard” means a tensile strength >1,400 N/mm.sup.2 and the term “soft” means a tensile strength <850 N/mm.sup.2.

[0037] One advantage of the invention is that a H pillar is produced whose soft regions are positioned so that an optimal crash behavior and in particular, folding behavior of the B pillar is assured, with an optimal flow of force into the rocker panel.