Bumper beam having an 8 shaped cross-section

Patent metadata

Field	Value
Publication number	US-10940815-B2
Application number	US-201716347374-A
Country	US
Kind code	B2
Filing date	Nov 16, 2017
Priority date	Nov 18, 2016
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

Abstract

A bumper beam made of at least one roll formed steel sheet is described. The bumper beam contains an upper beam and a lower beam extending in a transversal direction, the upper beam and the lower beam each having a closed cross-section defined by a front wall, a rear wall, an upper wall and a lower wall, the upper wall and the lower wall joining the front wall to the rear wall, and a central wall extending between the front walls, the rear walls of the upper beam and of the lower beam forming both the lower wall of the upper beam and the upper wall of the lower beam, the central wall extending in at least two different planes.

First claim

The invention claimed is:

1. A bumper beam for an automotive vehicle made of at least one roll formed steel sheet comprising an upper beam and a lower beam extending in a transversal direction, said upper beam and said lower beam each having a closed cross-section defined by a front wall, a rear wall, an upper wall and a lower wall, the upper wall and the lower wall joining the front wall to the rear wall,
wherein a central wall extends between the front walls, and the rear walls of the upper beam and of the lower beam and forms both the lower wall of the upper beam and the upper wall of the lower beam,
the central wall extends in at least two different planes,
the central wall comprises a front part extending from the front walls of the upper and lower beams, a rear part extending from the rear walls of the upper and lower beams and a central part joining the front part and the rear part, the front part and/or the rear part extending in a plane different from the plane in which the central part extends,
wherein the front part extends in a first plane, the rear part extends in a second plane, parallel to the first plane, and the central part extends in a third plane inclined between the first plane and the second plane, and
a junction between the central part and the front part being formed by a radiused portion extending between the central part and the front part, and
the radius of curvature of the radiused portion is greater than or equal to 0.5 times the thickness of the steel sheet.

2. The bumper beam according to claim 1 , wherein the first and second planes are parallel to the upper wall of the upper beam and to the lower wall of the lower beam.

3. The bumper beam according to claim 1 , wherein the front part extends at a first distance from the upper wall of the upper beam and the rear part extends at a second distance from the upper wall of the upper beam, the second distance being greater than the first distance.

4. The bumper beam according to claim 3 , wherein the difference between the first distance and the second distance is less than a third of the distance separating the upper wall of the upper beam from the lower wall of the lower beam.

5. The bumper beam according to claim 1 , wherein the front part is connected to the front wall of the upper beam by a radiused front end and wherein the rear part is connected to the rear wall of the lower beam by a radiused rear end.

6. The bumper beam according to claim 1 , wherein each of the front walls of the upper beam and of the lower beam comprises a front rib extending transversally and towards the interior of the bumper beam.

7. The bumper beam according to claim 6 , wherein at least one of the upper wall of the upper beam, the lower wall of the lower beam, the rear wall of the upper beam and the rear wall of the lower beam further comprises a rib extending transversally and towards the interior of the bumper beam.

8. The bumper beam according to claim 7 , wherein each of the rear walls of the upper beam and of the lower beam comprises a rear rib extending transversally and towards the interior of the bumper beam.

9. The bumper beam according to claim 1 , wherein the steel sheet is made of a steel having a tensile strength greater than or equal to 980 MPa.

10. The bumper beam according to claim 9 , wherein the steel sheet has a thickness between 0.8 mm and 1.5 mm.

11. The bumper beam according to claim 1 , wherein the bumper beam is curved in the transversal direction, the curvature radius of the bumper beam being less than or equal to 4000 mm.

12. The bumper beam according to claim 1 , wherein the steel sheet extends between a first edge and a second edge, the first edge being welded to the front wall of the upper beam and the second edge being welded to the rear wall of the lower beam.

13. The bumper beam according to claim 1 , further comprising a reinforcement element made of a steel sheet, said reinforcement element being attached to the upper beam and to the lower beam such that the reinforcement element extends opposite at least a part of the front walls of the upper beam and of the lower beam and defines with said front walls at least one cavity extending between said front walls and said reinforcement element.

14. A method for producing a bumper beam according to claim 1 , comprising the steps of:
providing a steel sheet,
roll forming the steel sheet in successive rolling stations in order to form a bumper beam comprising an upper beam and a lower beam extending in a transversal direction, said upper beam and said lower beam each having a closed cross-section defined by a front wall, a rear wall, an upper wall and a lower wall, the upper wall and the lower wall joining the front wall to the rear wall, a central wall extending between the front walls and the rear walls of the upper beam and of the lower beam forming both the lower wall of the upper beam and the upper wall of the lower beam,
wherein the central wall is shaped such that it extends in at least two different planes in at least one of the successive rolling stations.

15. The method according to claim 14 , further comprising a step of welding one of the edges of the steel sheet to the front wall of the upper beam and welding the other edge of the steel sheet to the rear wall of the lower beam.

16. The method according to claim 14 , wherein the steel sheet is made of a steel having a tensile strength greater or equal to 980 MPa.

Assignees

• Arcelormittal

Inventors

• Herisson Damien
• Lam Jimmy
• Hasenpouth Dan
• Gibeau Elie
• Viaux Ivan

Classifications

• B60R19/18 Primary

  {characterised by the cross-section;} Means within the bumper to absorb impact · CPC title

• B21D53/88

  other parts for vehicles, e.g. cowlings, mudguards · CPC title

• B21D5/086

  for obtaining closed hollow profiles · CPC title

• B60R2019/1826

  of high-tension steel · CPC title