GB1568228A - Impact energy-absorbing beam of a vehicle - Google Patents

Description

(54) AN IMPACT ENERGY-ABSORBING BEAM OF A VEHICLE (71) We, DR ING. h.c.F. PORSCHE AKTIENGESEUSCHAFT, of Porschestrasse 42, Stuttgart-Zuffenhausen, Germany, a German Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : The present invention relates to a beam, preferably fabricated from sheet steel, for absorbing energy of vehicles on impact and consisting of at least two parts which are joined by flanges.

In known beams such as shown in German Published Application 1,630,384, the horizontal and vertical walls are planar. As a result, with axial loading on the beam, these walls tend to collapse and, further, the relatively small radii of turned edges form reinforcements which also cause an undesirable buckling effect. Both such occurrences, i.e., collapsing and stiffening, lead to unstable behaviour of the beam during energy absorption. This, in turn, reduces the energy absorption efficiency of the beam.

It is one of the objects of the present invention to provide an energy-absorbing beam which, on the one hand, has good energy absorption efficiency and, on the other hand, can be readily fabricated by simple and known manufacturing methods and techniques.

We have overcome the problems encountered in the prior art by the present invention in order to prevent the collapsing of the beam during energy absorption. To this end, the present invention consists in a vehicle having a longitudinally extending beam for the absorption of impact energy of vehicles consisting of at least two parts fixedly connected by longitudinally extending flanges wherein the whole of the transverse cross-section of at least one of said parts between the flanges. is provided with an outwardly directed curvature over at least a portion of the beam length.

With the above-described features, the advantages of the present invention reside in the extensive avoidance of collapsing of the beam by virtue of the curvature. In addition, it is possible to discard at least part of any local reinforcement by virtue of the formation of the beam parts. Furthermore, the beam of the present invention uses parts which are simple to produce. The uniform, high force level obtained as a result thereof effects a large measuse of energy absorption throughout the deformation travel. Because of the small amount of material required, the beam of the present invention has a high specific energy absorption capability.

Inasmuch as the beam portions are fabricated from at least one part which is curved in cross-section, the manufacture of these parts is greatly simplified.

In the accompanying drawings: Figure 1 is a partial view of a schematically shown motor vehicle provided with a beam according to the present invention; Figure 2 is a sectional view taken along the line II--II of Figure 1 on an enlarged scale; Figures 3 to 5 are sectional views corresponding to Figure 2 but showing several different embodiments of the beam of the present invention; - Figure 6 is a plan view of the beam taken in the direction of arrow X of Figure 4, but on a smaller scale; Figure 7 is a sectional view taken along the line VIl-VIl of Figure 6; Figure 8 is a plan view similar to Figure 6 but showing another embodiment of the present invention; and Figure 9 is a sectional view taken along the line IX-IX of Figure 8.

Referring to Figure 1, there is shown a passenger motor vehicle 1 which includes a body 2, a windshield 3, and a dashboard 4. In front of the dashboard, as viewed in the driving direction, there is arranged a transverse beam 5 which extends transversely to a side portion stiffening plate 6 within a wing 7. A longitudinal beam 8, which can be fabricated from sheet steel, aluminium or other suitable material, extends parallel to the plate 6 aligned in the longitudinal direction A-A of the vehicle and is attached to the transverse beam 5 in a conventional manner (not shown). A hy draulically operated piston-and-cylinder arrangement 9 extends from the longitudinal beam 8 and carries an impact energyabsorbing bumper 10 for absorbing the impart energy of the passenger motor vehicle at speeds of about 5 miles/hr.

Referring now to Figure 2 for details of the longitudinal beam 8 which serves to absorb energy by deformation during high speed impact accidents, it can be seen that the beam 8 consists of parts 11 and 12 which are connected by weld flanges 13 and 14. As shown in Figure 3, the longitudinal beam 18 illustrating another embodiment of the present invention has symmetrical shells 19, 20 each having a curved cross-section.

The side portion stiffening plate 21 (corresponding to the side portion stiffening plates 6 of Figure 1) extends to the part 20 and is connected therewith by conventional means such as spot-welding, gluing or the like.

The curvatures 22, 23 are each formed by two curves radii R1 and R2, respectively.

The transition from the curvatures 22, 23 on the longer sides of the beam to the shorter sides consisting of parts 19, 20 is effected with radii R2.

In Figure 4, the longitudinal beam 18 is shown in a 1:2 scale. The shorter side D of the beam cross-section is 70 mm. and the longer side E is 100 mm. It has been found that a ratio of the shorter side of the beam cross-section to the longer side of the order of 1:1.42 is a favourable ratio for energy absorption. For a beam having a length F (Figure 1) of 300 to 600 mm., the radii of tile curvatures 22, 23 should have the following values: R, l = 100 mm.: R,2 = 200 mm.; R1.1 = 400 mm.; and Rl 4 = 500 mm. where Rut 2, R1, and Rl 4 are examples of radii which can extend over the length F. In other words one beam may have the radius Rl.l and anothre beam the radius Rut 2 However, it is also possible for the radii R1 to be as great as 900 mm. without departing from the scope of the present invention. Likewise, the transition radii R2 may vary in value from 10 to 25 mm.

Figure 5 illustrates yet another embodiment of the beam of the present invention in which the beam 24 has shells 25 and 26 each of curve-shaped cross-section. In vehicle superstructures, it is often necessary to provide tapers 28 and 29 on the beam 27 as shown in Figure 6. It has been found that these tapers should, when used with the present invention, be of the order of 10 to 20% the length of the beam. In order for the deformation of the beam 8 to commence and proceed effectively, a crosssectional reduceon 30 as shown in Figures 8 and 9 is provided at the forward end of the beam by means of pressed-in portions 31, 32 at portions 19 and 20.

WHAT WE CLAIM IS: 1. A vehicle having a longitudinally extending beam for the absorption of impact energy of vehicles consisting of at least two parts - fixedly connected by longitudinally extending flanges wherein the whole of the transverse cross-section of at least one of said parts between the flanges is provided with an outwardly directed curvature over at least a portion of the beam length.

2. A vehicle having a beam according to claim 1, wherein both parts are provided with the curvature.

3. A vehicle having a beam according to claim 2, wherein the parts are symmetrical at least for each section.

4. A vehicle having a beam according to claim 2 or 3, wherein the curvatures are formed by radii R1 - of between 100 mm and 900 mm.

5. A vehicle having a beam according to claim 4, wherein the beam is formed with longer sides and shorter sides, and the radii Rl are provided at the longer sides of the parts.

6. A vehicle having an beam according to claim 5, wherein the flanges are provided at the shorter sides of the parts.

7. A vehicle having a beam according to claim 5 or 6, wherein transition radii R2 are provided between the curvature along the length of the longer sides and a rim on the shorter sides.

8. A vehicle having a beam according to any of claims 5 to 7, wherein the ratio of the length of the shorter sides of the beam to the longer sides of the beam is betwene 1:1.3 to 1:1.5.

9. A vehicle having a beam according to any one of the preceding calims, wherein the length of the beam is between 300 to 600 mm.

10. A vehicle having a beam according to any one of the preceding claims, wherein the beam is provided with tapers in the size range of between 10- and 20% the length of the beam.

11. A vehicle having a beam according to any one of the preceding claims, wherein the beam is made from sheet metal.

12. A vehicle having a beam according to any one of the preceding claims, wherein a cross-sectional constriction is provided in the vicinity of the forward end of the beam as viewed in the driving direction of the vehicle.

13. A vehicle having beams for the impact absorption of energy substantially as described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. draulically operated piston-and-cylinder arrangement 9 extends from the longitudinal beam 8 and carries an impact energyabsorbing bumper 10 for absorbing the impart energy of the passenger motor vehicle at speeds of about 5 miles/hr. Referring now to Figure 2 for details of the longitudinal beam 8 which serves to absorb energy by deformation during high speed impact accidents, it can be seen that the beam 8 consists of parts 11 and 12 which are connected by weld flanges 13 and 14. As shown in Figure 3, the longitudinal beam 18 illustrating another embodiment of the present invention has symmetrical shells 19, 20 each having a curved cross-section. The side portion stiffening plate 21 (corresponding to the side portion stiffening plates 6 of Figure 1) extends to the part 20 and is connected therewith by conventional means such as spot-welding, gluing or the like. The curvatures 22, 23 are each formed by two curves radii R1 and R2, respectively. The transition from the curvatures 22, 23 on the longer sides of the beam to the shorter sides consisting of parts 19, 20 is effected with radii R2. In Figure 4, the longitudinal beam 18 is shown in a 1:2 scale. The shorter side D of the beam cross-section is 70 mm. and the longer side E is 100 mm. It has been found that a ratio of the shorter side of the beam cross-section to the longer side of the order of 1:1.42 is a favourable ratio for energy absorption. For a beam having a length F (Figure 1) of 300 to 600 mm., the radii of tile curvatures 22, 23 should have the following values: R, l = 100 mm.: R,2 = 200 mm.; R1.1 = 400 mm.; and Rl 4 = 500 mm. where Rut 2, R1, and Rl 4 are examples of radii which can extend over the length F. In other words one beam may have the radius Rl.l and anothre beam the radius Rut 2 However, it is also possible for the radii R1 to be as great as 900 mm. without departing from the scope of the present invention. Likewise, the transition radii R2 may vary in value from 10 to 25 mm. Figure 5 illustrates yet another embodiment of the beam of the present invention in which the beam 24 has shells 25 and 26 each of curve-shaped cross-section. In vehicle superstructures, it is often necessary to provide tapers 28 and 29 on the beam 27 as shown in Figure 6. It has been found that these tapers should, when used with the present invention, be of the order of 10 to 20% the length of the beam. In order for the deformation of the beam 8 to commence and proceed effectively, a crosssectional reduceon 30 as shown in Figures 8 and 9 is provided at the forward end of the beam by means of pressed-in portions 31, 32 at portions 19 and 20. WHAT WE CLAIM IS:

1. A vehicle having a longitudinally extending beam for the absorption of impact energy of vehicles consisting of at least two parts - fixedly connected by longitudinally extending flanges wherein the whole of the transverse cross-section of at least one of said parts between the flanges is provided with an outwardly directed curvature over at least a portion of the beam length.

2. A vehicle having a beam according to claim 1, wherein both parts are provided with the curvature.

3. A vehicle having a beam according to claim 2, wherein the parts are symmetrical at least for each section.

4. A vehicle having a beam according to claim 2 or 3, wherein the curvatures are formed by radii R1 - of between 100 mm and 900 mm.

5. A vehicle having a beam according to claim 4, wherein the beam is formed with longer sides and shorter sides, and the radii Rl are provided at the longer sides of the parts.

6. A vehicle having an beam according to claim 5, wherein the flanges are provided at the shorter sides of the parts.

7. A vehicle having a beam according to claim 5 or 6, wherein transition radii R2 are provided between the curvature along the length of the longer sides and a rim on the shorter sides.

8. A vehicle having a beam according to any of claims 5 to 7, wherein the ratio of the length of the shorter sides of the beam to the longer sides of the beam is betwene 1:1.3 to 1:1.5.

9. A vehicle having a beam according to any one of the preceding calims, wherein the length of the beam is between 300 to 600 mm.

10. A vehicle having a beam according to any one of the preceding claims, wherein the beam is provided with tapers in the size range of between 10- and 20% the length of the beam.

11. A vehicle having a beam according to any one of the preceding claims, wherein the beam is made from sheet metal.

12. A vehicle having a beam according to any one of the preceding claims, wherein a cross-sectional constriction is provided in the vicinity of the forward end of the beam as viewed in the driving direction of the vehicle.

13. A vehicle having beams for the impact absorption of energy substantially as described with reference to the accompanying drawings.