The invention relates to an A-pillar for a vehicle including a first part extending as far as the windscreen and supporting the door hinges and a second arcuate part extending along the windscreen and continuing towards the back in order to serve as a roof beam above the door, the said second part consisting of two sections with longitudinal flanges arranged in pairs and welded together so as to form a closed profile.
The pillar from which the front door of a vehicle is normally suspended is referred to as an A-pillar. This pillar extends up along the windscreen and is connected to the roof beam above the doors. In the event of a lateral collision, the passenger is protected by the door, as well as by the A-pillar in front of the door, the B-pillar behind the door, the sill member below the door and the roof beam above the door. B-pillars the edges of which are trimmed after forming and hardening are known from U.S. Pat. No. 7,278,287 B2. The pillars are manufactured with soft edges in order to reduce the wear of the edge-trimming tool.
One aim of the invention is to improve the protection for passengers in the event of a lateral collision against the front door. This is achieved in that at least one of the sections forming the A-pillar is press-hardened and has a breaking strength in excess of 1400 MPa and both of the flanges in at least one pair of flanges welded together have a breaking strength below 1100 MPa in a portion situated above the door. This increases the protection for the passenger closest to the door. The invention is defined by the claims.
As shown in
The other section 24 can be manufactured in the same manner with the same high strength and the same lower strength in the flanges. However, this section 24 may also be cold-formed in a steel having a strength below 1100 MPa, e.g. with a strength of 500-1000 MPa. Flanges welded together in pairs advantageously have approximately the same strength and ductility. The section 24 may have a smaller sheet thickness than the section 23, particularly if it is cold-formed.
The flanges 25, 26 have this lower strength in the region shown by the line 35 between the region for the attachment of the cross member 17 and the region for the attachment of the B-pillar 13. The flanges may also have this lower strength in a portion immediately in front of the C-pillar of the vehicle, as shown by the reference numeral 36, in order to protect the head of the back seat passenger. Other parts of the flanges may advantageously be fully hardened.
In the event of a lateral collision against a pillar or a tree hitting the front door, the lower strength and greater ductility of the flanges reduces the risk of crack formation leading to fracture of the A-pillar before it has absorbed the maximum amount of energy by plastic deformation, thereby improving the protection for the passenger sitting beside the door. The same thing applies to the back seat passenger if the flanges have a soft zone in front of the C-pillar.
Number | Date | Country | Kind |
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0901549-6 | Dec 2009 | SE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/SE2010/000295 | 12/11/2010 | WO | 00 | 6/11/2012 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2011/071433 | 6/16/2011 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
5972134 | Buschsieweke et al. | Oct 1999 | A |
6962389 | Katsuma | Nov 2005 | B2 |
7278287 | Bohner et al. | Oct 2007 | B2 |
7678208 | Bodin | Mar 2010 | B2 |
Number | Date | Country |
---|---|---|
WO2009123538 | Oct 2009 | WO |
Number | Date | Country | |
---|---|---|---|
20120319432 A1 | Dec 2012 | US |