SHOCK-ABSORBING SYSTEM FOR A MOTOR VEHICLE

Abstract

The invention relates to a shock-absorbing system (10) for a motor vehicle, intended to be interposed between a side member (20) and a transverse impact beam (30), characterised in that it comprises: an absorbing element (40) that is able to irreversibly disintegrate at least partially in reaction to an impact, a connecting element (50) comprising at least one wall (60) having an end intended to be secured to the beam (30) and another end intended to be secured to the side member (20), the wall (60) having a programmed zone of mechanical weakness that allows the wall (60) to fold in the event of an impact.

Claims

1. Shock-absorbing system (10) for a motor vehicle, intended to be interposed between a side member (20) and a transverse impact beam (30), characterised in that it comprises: an absorbing element (40) that is able to irreversibly disintegrate at least partially in reaction to an impact; a connecting element (50) comprising at least one wall (60) having an end intended to be secured to the impact beam (30) and another end intended to be secured to the side member (20), the wall (60) having a programmed zone of mechanical weakness (66) that allows the wall (60) to fold in the event of an impact.

2. Shock-absorbing system (10) according to the preceding claim, wherein the absorbing element is able to disintegrate by delamination.

3. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) comprises, at its end intended to be positioned on the side of the beam (30), an initiator which initiates delamination by compression of the absorbing element (40) in the direction of the impact.

4. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) is able to delaminate over its entire length.

5. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) is positioned inside the connecting element (50).

6. Shock-absorbing system (10) according to one of the preceding claims, wherein the programmed zone of mechanical weakness (66) comprises a pre-fold, a slit or a thickness reduction.

7. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) is a hollow body, preferably a tube having a cross-section selected from the following list: circular, rectangular, conical, hexagonal, scalable.

8. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) does not consist of an assembly of different parts.

9. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) comprises at least one layer of composite material having a plastic matrix and reinforcement elements.

10. Shock-absorbing system (10) according to the preceding claim, wherein the matrix is a thermoplastic material, preferably selected from the following materials: polyamide, polypropylene, polyurethane.

11. Shock-absorbing system (10) according to claim 9, wherein the matrix is a thermosetting material, preferably selected from the following materials: epoxy, polyester, vinyl ester.

12. Shock-absorbing system (10) according to one of claims 9 to 11, wherein the reinforcement elements are continuous fibres, preferably based on a material selected alone or in combination from the following materials: carbon, glass, aramid.

13. Shock-absorbing system (10) according to one of claims 9 to 12, wherein the reinforcement elements are unidirectional fibres oriented in a direction not parallel to a longitudinal direction of the vehicle.

14. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) comprises internal ribs (45).

15. Shock-absorbing system (10) according to one of the preceding claims, wherein the absorbing element (40) is manufactured by reactive pultrusion or by extrusion.

16. Shock-absorbing system (10) according to one of the preceding claims, wherein the connecting element (50) has an incompressibility rate of less than 5% after an impact.

17. Assembly of a beam (30), a side member (20) and a shock-absorbing system (10) according to any one of the preceding claims, characterised in that the shock-absorbing system (10) is secured respectively to the beam (30) and to the side member (20) by attachment plates (70, 80).

18. Assembly according to the preceding claim, wherein the shock-absorbing system (10) is inserted in the plates (70, 80) outside the compression area, so as not to generate an incompressible residue between the two plates (70 and 80).

19. Impact beam (30), characterised in that it comprises at least one shock-absorbing system (10) according to one of claims 1 to 16.

20. Motor vehicle front module, characterised in that it comprises at least one shock-absorbing system (10) according to one of claims 1 to 16.

21. Motor vehicle, characterised in that it comprises at least one shock-absorbing system (10) according to one of claims 1 to 16.

22. Method for assembling an assembly according to claim 17 or 18, characterised in that it comprises the following steps: mounting on the connecting element (50) the attachment plate (70) for securing the shock-absorbing system (10) to the beam (30); arranging the absorbing element (40) inside the connecting element (50); mounting on the connecting element (50) the attachment plate (80) for securing the shock-absorbing system (10) to the side member (20); securing the side member (20) to the shock-absorbing system (10); and securing the shock-absorbing system (10) to the beam (30).

Description

[0050] The invention will be better understood on reading the accompanying figures, which are given solely by way of example and not limiting in any way, in which:

[0051] FIGS. 1A and 1B show a shock-absorbing system according to one embodiment of the invention; FIG. 1A shows the portion intended to be secured to the beam, and FIG. 1B shows the portion intended to be secured to the side member;

[0052] FIG. 2 shows an assembly of a beam, side members and a shock-absorbing system of FIG. 1; and

[0053] FIG. 3 shows various steps of assembling an assembly of FIG. 2.

[0054] We now refer to FIGS. 1A, 1B and 2 which show an example of a shock-absorbing system 10 for a motor vehicle according to the invention. This system 10 is intended to be interposed between a side member 20 and a transverse impact beam 30. It comprises: [0055] an absorbing element 40 that is able to irreversibly disintegrate at least partially in reaction to an impact, for example by delamination; [0056] a connecting element 50, intended to be connected to the side member 20 and to the impact beam 30, comprising at least one wall 60 having an end intended to be secured to the beam 30 and another end intended to be secured to the side member 20, the wall 60 having a programmed zone of mechanical weakness 66 that allows the wall 60 to fold in the event of an impact.

[0057] According to one embodiment, the impact beam absorber is configured so that the initiator is on the side of the bar, such that the absorber compresses substantially longitudinally from the bar towards the side members (direction X in the vehicle coordinate system). The initiator is therefore preferably located towards the front of the tube, more preferably at its end so that delamination occurs from the front towards the rear.

The Absorbing Element 40

[0058] According to one embodiment, the absorbing element 40 is a hollow body, preferably a tube having a cross-section selected from the following list: circular, rectangular, conical, hexagonal, scalable.

[0059] Advantageously, the absorbing element 40 is made in one piece, in other words it is not manufactured by assembling different parts. It may, for example, be manufactured by moulding composite material, in particular by reactive pultrusion or by extrusion.

[0060] According to one embodiment, the absorbing element 40 comprises at least one layer of composite material having a plastic matrix and reinforcement elements.

[0061] The plastic matrix is, for example, a thermoplastic material, preferably selected alone or in combination from the following materials: polyamide, polypropylene, polyurethane.

[0062] The plastic matrix may alternatively be a thermosetting material, preferably selected alone or in combination from the following materials: epoxy, polyester, vinyl ester.

[0063] The reinforcement elements may be continuous fibres, preferably based on a material selected alone or in combination from the following materials: carbon, glass, aramid.

[0064] The reinforcement elements are preferably unidirectional fibres oriented in a direction not parallel to a longitudinal direction of the vehicle.

[0065] Advantageously, the absorbing element 40 comprises internal ribs 45.

[0066] According to an example shown on FIGS. 1A and 1B, the absorbing element 40 advantageously consists of a composite tube with continuous reinforcements, continuously connected at the front to the bar of the impact beam 30 and at the rear to the side member 20 or to the plate of the side member 20.

[0067] The absorbing element 40 comprises, at its end intended to be positioned on the side of the beam 30, an initiator which initiates delamination by compression of the absorbing element 40 from the front towards the rear (in the direction of the impact), and which deforms according to a delamination mode. This tube is able to delaminate over substantially its entire length.

[0068] According to one embodiment, shown on FIGS. 1A to 3, the absorbing element 40 is positioned inside the connecting element 50, the programmed zone of mechanical weakness 66 being planned so that the wall of the connecting element folds, for example, towards the outside of the connecting element 50.

[0069] The programmed zone of mechanical weakness 66 comprises a pre-fold, a slit or a thickness reduction.

The Connecting Element 50

[0070] The connecting element 50, between the impact beam 30 and the side member 20, forms a guiding system not continuously connected to the absorbing element 40 (composite tube on the figures). One of its functions is to guide the absorbing element 40 during its compression in the event of an impact, without however contributing to energy absorption. It allows a connection after an impact between the bar of the impact beam 30 and the side member 20 of the vehicle. It has the ability to deform, in particular due to the programmed zone of mechanical weakness 66, and not generate an incompressible residue after total compression.

[0071] Advantageously therefore, the connecting element 50 has an incompressibility rate of less than 5% after an impact.

[0072] The invention also relates to an assembly of an impact beam 30, a side member 20 and at least one shock-absorbing system 10 according to the invention.

[0073] The shock-absorbing system 10 is secured to the impact beam 30 by an attachment plate 70, and to the side member 20 by an attachment plate 80.

[0074] The plates 70 and 80 comprise recesses 75 and 85, or housings, to accommodate, for example by insertion, the tube forming the absorbing element 40.

[0075] To avoid generating an incompressible residue between the two plates 70 and 80, the tubes (absorbing element 40) are inserted in the plates 70 and 80 outside the compression area (see FIGS. 1A and 1B). During a compression after an impact in fact, one side of the plate 70 may come into contact with one side of the plate 80. As shown on FIGS. 1A and 1B, the entire portion of the absorbing element 40 between these two sides will be delaminated.

[0076] The invention also relates to a method for assembling such an assembly comprising the following steps (FIG. 3): [0077] mounting on the connecting element 50 the attachment plate 70 for securing the shock-absorbing system 10 to the beam 30; [0078] arranging the absorbing element 40 inside the connecting element 50; [0079] mounting on the connecting element 50 the attachment plate 80 for securing the shock-absorbing system 10 to the side member 20; [0080] securing the side member 20 to the shock-absorbing system 10; and [0081] securing the shock-absorbing system 10 to the beam 30.

[0082] FIG. 3 also shows a step of securing a towing system 90.

[0083] The invention also relates to an impact beam 30, comprising at least one shock-absorbing system 10 according to the invention.

[0084] The invention also relates to a motor vehicle front module comprising at least one shock-absorbing system 10 according to the invention.

[0085] The invention also relates to a motor vehicle comprising at least one shock-absorbing system 10 according to the invention.

LIST OF REFERENCES

[0086] 10: shock-absorbing system [0087] 20: side member of the motor vehicle [0088] 30: transverse impact beam of the motor vehicle [0089] 40: absorbing element of the shock-absorbing system 10 [0090] 45: internal ribs of the absorbing element 40 [0091] 50: connecting element, of the shock-absorbing system 10, between the impact beam 30 and the side member 20 [0092] 60: wall of the connecting element 50 [0093] 66: programmed zone of mechanical weakness of the wall 60 [0094] 70: attachment plate for securing the shock-absorbing system 10 to the impact beam 30 [0095] 75: recesses of the attachment plate 70 [0096] 80: attachment plate for securing the shock-absorbing system 10 to the side member 20 [0097] 85: recesses of the attachment plate 80 [0098] 90: towing system