WO2008020793A1

WO2008020793A1 - A bumper beam

Info

Publication number: WO2008020793A1
Application number: PCT/SE2007/000703
Authority: WO
Inventors: Martin BRÖMS
Original assignee: Gestamp Hardtech Ab
Priority date: 2006-08-15
Filing date: 2007-08-01
Publication date: 2008-02-21
Also published as: SE530206C2; SE0601678L

Abstract

A bumper beam comprises a hat-shaped beam with a cover. The cover has a number of indentations (25-28) into the hat beam, which are welded to the inside of the hat beam and render the bumper beam torsionally rigid.

Description

A Bumper beam

Technical field

The present invention relates to a bumper beam comprising a hat-shaped beam with a crown and side flanges and a cover attached to the side flanges, with the crown pointing in towards the vehicle.

State of the art

Bumper beams of the hat beam type which have their crown pointing in towards the vehicle are known. A cover results in the bumper beam taking a high load before it begins to deform plastically, as is often desired. Where a collision does not act centrally in the height direction but only upon, for example, the lower portion, the bumper beam will tend to twist and therefore not function satisfactorily. Such collisions are usual when a high vehicle, e.g. an SUV, runs into a passenger car with a lower- positioned bumper.

Object of the invention

It is an object of the invention to provide a bumper beam of this kind which takes a high load before it begins to deform and which also has improved torsional rigidity. The bumper beam is in addition intended to be easy to manufacture at low cost and be of low weight relative to its performance. This is achieved with a bumper beam as defined by the claims.

Brief description of the drawings

Figure 1 is a front view of a bumper beam according to the invention.

Figure 2 is a front view of a cover which is part of the bumper beam shown in Figure 1. Figure 3 depicts the bumper beam cover in Figure 2 as seen from above.

Figure 4 is an isometric view of the bumper cover shown in Figures 2 and 3.

Figure 5 is a cross-section along the line 5-5 in Figure 1.

Figure 6 is a cross-section along the line 6-6 in Figure 1.

Figure 7 is a view of an alternative design of the bumper beam cover shown in Figures 2 and 3.

Description of preferred and depicted embodiment example

Figure 1 depicts a hat beam as seen from outside the vehicle. Figures 5 and 6 are cross-sections of the beam, which comprises a hat-shaped beam 11 and a cover 12. The hat beam has a central flange 14, two webs 15,16 and two side flanges 17,18, i.e. it has a crown 14-16 pointing in towards the vehicle. The cover 12 has a number of flat portions 20-24 welded to the hat beam's side flanges 17,18. The hat beam is slightly curved as illustrated in Figure 3, which shows the curvature of the cover 12.

Between the flat portions 20-24, the cover has indentations 25-28 which extend almost down to the hat beam's central flange 14 and are welded to the webs 15,16, i.e. welded to the inside of the hat beam's crown. The indentations 25-28 are intended to abut against the hat beam's inner surfaces and be welded along the abutment, preferably along the whole abutment indicated by refs. 30,31. Figure 7 depicts an alternative form of the cover 12 which has pairs of tabs 33,34,35 at each indentation. These tabs may be attached to the hat beam by spot welding. The whole abutment against the webs is thus in this case not welded, but still it is possible to achieve satisfactory torsional rigidity and with line welding it is possible to have breaks in the welds. Even without welding the indentations to the inside of the hat beam, greatly improved torsional rigidity results.

The bumper beam depicted provides significantly improved torsional rigidity without a particularly large increase in weight relative to a corresponding bumper beam with an unindented cover. The bumper beam may be attached to the vehicle in various different ways. The central flange 14 may for example have holes for bolts which are fastened in an attachment plate on the vehicle, in which case the cover 12 will have holes 36,37 to allow the bolts to be tightened.

Claims

1. A bumper beam comprising a hat-shaped beam (11) with a crown (14-16) and side flanges (17,18) and a cover (14) which is fastened to the side flanges, with the crown facing the vehicle, characterised in that the cover (14) has a number of indentations (25-28) in the crown, which extend across the whole width of the cover, and the width of the cover is so adapted that the edges of the indentations abut against the sides of the crown.

2. A bumper beam according to claim 1 , characterised in that the indentations are welded to the sides of the crown.

3. A bumper beam according to claim 1 , characterised in that the indentations (25-28) extend in to at least three-quarters of the depth of the crown.

4. A bumper beam according to claim 2, characterised in that the indentations (25-28) have tabs (33-35) which are spot-welded to the inside of the hat beam.

5. A bumper beam according to claim 2, characterised in that the indentations

(25-28) are seam-welded to the inside of the crown.