EP3164317A1

EP3164317A1 - Improved reinforcing transverse cross-member with programmed rupture

Info

Publication number: EP3164317A1
Application number: EP15745520.5A
Authority: EP
Inventors: Dominique Jourdan; Marine MENAND; Catherine TUAL
Original assignee: Peugeot Citroen Automobiles SA
Current assignee: PSA Automobiles SA
Priority date: 2014-07-04
Filing date: 2015-06-19
Publication date: 2017-05-10
Also published as: FR3023250B1; FR3023250A1; WO2016001510A1

Abstract

The invention relates to an underbody of a vehicle, comprising a floor (2) with a central tunnel and a cross-member (1), characterised in that said cross-member (1) is fixed to the outer surface of the floor (2) located on the outer side of the vehicle (3) when the floor (2) is fitted to the vehicle, and said cross-member (3) comprises a segment in the middle of the length thereof, in the form of a curved « Ω » shape, arranged to as to be inserted into said tunnel.

Description

IMPROVED TRANSVERSE CROSS STRAP WITH PROGRAM BREAK

The invention relates to a vehicle floor cross member for reinforcing the floor in the event of a side impact. The body structure of a vehicle is designed to absorb as much energy as possible during an impact. In the case of a side impact, the cockpit must remain relatively preserved to protect its occupants. Generally, in order to withstand a side impact, the motor vehicles comprise at least one transverse reinforcing cross member located on the floor of the vehicle, on the side of the passenger compartment. This crossbar extends from one lateral side of the vehicle to the other lateral side, substantially perpendicular to the longitudinal axis of the vehicle. To respond to the hardening of side impact test protocols, the current trend is to strengthen the reinforcing beam located against the floor of the vehicle.

For example, patent EP0799757 discloses a floor reinforcing crossbar for lateral impact, extending between each side of the vehicle. Said reinforcing beam has a U-shaped section, the ends of the branches of the "U" being fixed on the floor surface. The cross member is disposed on the face of the floor facing the side of the passenger compartment of the vehicle. To recover the forces in the event of side impact, the crossbar is directly attached to the side rails of the vehicle. The floor of the vehicle forms a tunnel extending along the floor along the longitudinal axis of the vehicle, in the median axis of said vehicle. This tunnel creates an elevated part of the passenger compartment floor. At the level of said tunnel, the height of the branches of the U of the cross section of the reinforcement is reduced in order to follow the altitude difference of the tunnel.

This solution has the advantage of offering good impact resistance. However, such a reinforcement structure of a vehicle floor creates a large volume structure in the passenger compartment. Passenger comfort, including the space available for the feet, is degraded. In addition, made of sheet steel, this solution increases the mass of the vehicle. The present invention aims to strengthen the floor to the side impact. More particularly, the invention aims to improve the lateral impact resistance of a vehicle floor having a central tunnel. Another objective is to avoid deformation of the floor in the part under each front seat in case of side impact. Another objective is to lighten the structure of the vehicle without degrading its resistance to side impact. Another objective is to improve the lateral impact resistance of the vehicle structure without impacting the passenger compartment volume, particularly at the feet of the rear passengers. This object is achieved according to the invention by means of a vehicle underbody comprising a floor with a central tunnel extending in a longitudinal direction of the floor and forming an elevation of said floor on the passenger side of the vehicle, and a cross member extending between the edges side of said floor in a transverse direction perpendicular to the longitudinal direction, the side edges being the edges of the floor along the side edges of the vehicle when the floor is installed on the vehicle, characterized in that said cross is fixed against the outer surface of the floor located on the outside of the vehicle when the floor is installed on the vehicle, and said cross has a segment in the middle of its length in a curved "Ω" shape arranged to fit into said tunnel. Advantageously, the cross-member can thus strengthen the tunnel of the floor. Indeed, in case of side impact on a vehicle with a floor with a central tunnel, the tunnel creates a fragile area that will quickly deform, and cause a deformation of the entire floor. The width of the passenger compartment will decrease. By giving the transom this "Ω" shape, which follows the shape of the tunnel, the transom strengthens the tunnel's resistance in the event of a lateral impact, and retards its deformation, while maintaining a space in the tunnel for the passage of elements. vehicle technique, such as an exhaust pipe, pipes or a transmission shaft. Another advantage is that this "Ω" shape creates a less resistant zone than the rest of the body, because of the curvature. Thus, in the event of a lateral impact, if the forces are too great, the central part of the body comprising this "Ω" shape may break or be deformed before the parts of the body situated around said central zone in "Ω" and which form side arms of the body. When the cross member is attached to a vehicle floor having a tunnel, each of the lateral arms of the crossbar is generally located substantially at the floor area on which is placed one of the front seats. The fragility created by the "Ω" shape makes it possible to prevent one of the arms from breaking or deforming, and thus to avoid reducing the area of the floor on which a seat is fixed. Once the body has broken or distorted at the "Ω" shape, the arms will continue to strengthen the parts of the floor to which they are attached. Passenger safety is improved.

The arrangement on the outer surface has the advantage of not encroaching on the volume of the passenger compartment of the vehicle. In particular, this arrangement avoids creating volumes on the vehicle floor vehicle side. The comfort of the passengers is not degraded.

In a preferred embodiment of the invention, the cross member comprises at least one body of composite material.

Advantageously, the use of a composite material makes it possible to make a cross body lighter than a steel cross member, while being rigid.

In another embodiment of the invention, the crossmember comprises deformable end pieces fixed at least at two ends of said body, said end pieces being intended to connect said ends of the body to elements of the lateral structure of the vehicle, in particular to the side members. .

The composite materials may have low deformation capacity, in particular in flexion or torsion when they are subjected at the same time to a compressive force, the deformable tips placed at the ends of the body and intended to connect the cross member to the lateral structure of the vehicle, advantageously allow to pass essentially only compression forces in the body. Indeed, said end pieces will be absorbed by deforming the forces other than compression forces, such as bending forces related to the rotation of the lateral structure of the vehicle elements on which the cross is connected. The risks that the body of composite material is broken down are thus reduced. Preferably, the body is configured so that its ends are not in contact with the elements of the lateral structure of the vehicle, and said ends of the body are connected to the elements of the lateral structure of the vehicle the end pieces. Thus, the cross member of composite material is lightweight, resistant, and accepts the deformations at these connections with the structural elements of the vehicle. Another advantage is that the end pieces allow to absorb some of the forces of the shock in the transverse direction of the vehicle. Thus, in the event of a side impact, part of the energy of the shock is dissipated in the deformation of said end pieces. The efforts transmitted to the body are diminished. Preferably, the tips are made of metallic material. in order to have good mechanical strength and good ability to deform without breaking. The end pieces may be fixed by gluing, riveting, or any other fixing means known to those skilled in the art. The tips can be made of steel for easier shaping or for a low cost, or aluminum to reduce the weight.

In another embodiment of the invention, the end-pieces comprise zones of rupture programmed so as to allow a programmed deformation of said end-pieces.

Thus advantageously, the deformation of the tip is better controlled. Several programmed break zones can be applied. For example, surfaces of the cross member may have an "accordion" type shape to allow controlled deformation of the tip.

In another embodiment of the invention, the floor is made of composite material.

In another embodiment of the invention, the cross member comprises at least one extension arranged to extend in a direction parallel to the floor and different from the direction substantially perpendicular to the longitudinal direction of the floor.

Thus, when the crossbar is fixed on a vehicle floor, the cross member reinforces the floor in the event of a side impact, and in the event of a frontal impact, the extension reinforces the floor around said cross-member opposite forces perpendicular to the floor by distributing said forces over a larger area.

Indeed, in case of frontal impact, the rear fasteners of the front seats will transmit efforts on the floor. These efforts have a component perpendicular to the large floor, which tends to pull on said floor and from the pivoting of the seats along an axis of rotation parallel to the transverse axis of the vehicle. By positioning the cross member on the floor of the vehicle so that the cross member is at near or approximately vis-à-vis with the rear fasteners of the front seats of the vehicle, and extending along the transverse axis of the vehicle to be connected at least by two opposite ends to side structure elements of the vehicle, as per example of the longitudinal members, and so that the extension of the cross is oriented towards the rear of the vehicle, the floor is more resistant to these drawing efforts through cooperation with said cross which distributes these draw forces on a plus large floor area

In the case where the crosspiece has only one extension, said extension is preferably positioned at least in part at the segment following the curve shape in "Ω". Thus, the extension makes it possible to increase the inertia of the segment of the central part of the crossbar in the form of "Ω", and thus to allow said crossmember to spend more effort in the segment traversing said shape in "Ω ". The extension reinforces this central part of the crossbar in the form of "Ω". In this case, preferably, the width of the extension, that is to say the dimension of the extension in a direction perpendicular to the longitudinal direction of the floor, is greater than the length of the segment of the body. shape in "Ω", that is to say its dimension in the same longitudinal direction.

The invention also relates to a vehicle comprising a base as described above and whose cross member has an extension, and which comprises a heel board connected to the floor, the extension extending to the connection of the floor with said board. heel.

Thus, advantageously, in case of front impact, this arrangement allows to transfer the pulling forces from the rear fasteners of the front seats on the floor to the heel board. The risk of deformation or even tearing of the floor are reduced. The safety of the floor is improved.

The invention also relates to a method of manufacturing a vehicle with a base whose cross-member comprises at least one body and end pieces, the method comprising at least the steps

fixing the body on a floor to form the underbody - fastening of the underbody between the lateral structures of the vehicle, in particular between the longitudinal members attachment of the tips at least on the body and an element of the lateral structure of the vehicle.

Preferably, the manufacturing process will follow the steps in this order: fixing the body on the floor, laying and fixing the floor on the edges of the beams for receiving said floor, the edges of the side members being oriented towards the roof of the vehicle so the floor is placed on said longitudinal members, and mounting of the end pieces between the body and said longitudinal members. The end pieces can in addition be fixed to the floor.

Thus, advantageously, the mounting of the floor and the cross member on the vehicle structure is simplified.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings, in which:

- Fig. 1 is a perspective view of a body of a cross member according to one embodiment of the invention, without the end pieces.

- Fig. 2 is a view from below of a vehicle base comprising a floor with a tunnel and equipped with a cross member comprising a body as described in fig.l and end caps.

- Fig. 3 is a view of one end of the body equipped with a nozzle according to a particular embodiment of the invention.

- Fig. 4 is a view of a vehicle underbody comprising a floor and a cross member whose body has an extension directed rearward of the vehicle floor, in the central zone of said body.

The drawings are schematic representations to facilitate the understanding of the invention. The components are not necessarily represented on the scale. The same references correspond to the same components from one figure to another.

Fig. 1 shows a body 11 of a vehicle floor reinforcement cross member 1, intended to be placed on the exterior side face of a vehicle floor which comprises a central tunnel. The central tunnel extends in a longitudinal direction. The body 11 has a substantially U-shaped section, and has a curved area 13, forming a "Ω", along a segment substantially at the middle of the length of said body 11, the length of said body 11 being its dimension in the direction given by these two ends, intended to follow the shape of the tunnel of the floor forming a part convex side of the vehicle. The ends of the shape of the "U" section of the body 11 has fallen edges forming surfaces arranged to be pressed against the floor and intended to receive floor fastening means. The body is preferably made of composite material, for example in a material called composite SMC which is a thermoset semi-product consisting of a sheet of cut or continuous son impregnated with a mixture of polyester resin, fillers and various adjuvants. It is fixed by gluing to the floor. Other fastening means may be used, such as a fastening by rivet or, in the case of a floor made of composite material, by welding by melting the resin of the composite material of the body 11 and that of the floor 2, then plating the two pieces against each other until the material cools. Other materials may be used to make the body 1, such as steel or aluminum sheet. In the case of a flat floor 2, that is to say without tunnel, the curved area 13 forming an "Ω" of the body 1 can be arranged in a plane parallel to the floor plane of the vehicle when the body is fixed on the floor. The "U" shape of the section of the body 11 corresponds to a shape comprising two parallel branches interconnected by a base. Said base of the "U" shape is preferably of substantially planar shape, and comprises in places

depressions 15 which serve to stiffen the body 11. Alternatively, the base of the "U" of the section of the body 11 may comprise corrugations in the direction of the length of the body 11, that is to say along the axis transverse of the vehicle when the body 11 is mounted on said vehicle. Other forms may be considered

Alternatively, the cross member 1 can be positioned on the floor of the passenger side of the vehicle.

Fig. 2 shows the body 11 mounted on a floor 2 of the vehicle 3 and the floor 2 positioned between the two longitudinal members 31. The length of the body 11 is less than the distance between the two longitudinal members 31. The body 11 is fixed to the floor 2 before the mount the floor 2 on the vehicle. Then the floor 2 is installed on the vehicle so as to be supported by the longitudinal members 31, the body 1 passing between the longitudinal members 31. The floor 2 equipped with the cross member 1 forms a base. Preferably, the length of the body 11 will be chosen so as to leave a space between each end of the body 11 and each spar 31. A tip 12 is fixed by a side to one end of the body 11 and the other to one of the longitudinal members 31. The body 11 and the end pieces 12 form the cross member 1 which thus extends between the two longitudinal members 31 along the transverse axis of the vehicle.

Preferably, the cross member 1 is positioned to be substantially vis-à-vis with the middle legs of the vehicle structure 3 so as to recover the forces in case of side impact. Other positions along the longitudinal axis of the vehicle 3 when the floor 2 is installed on a vehicle can be envisaged.

In the event of a side impact, the forces experienced by the spar 31 located on the shock side are transmitted to the body 11 via the end pieces 12. The end pieces 12 are preferably arranged so as to be deformable in the event of a side impact. They can be made for example of sheet steel. The end pieces 12 may have shapes with programmed deformation zones, such as for example a shape having accordion edges as illustrated in FIG. 3, to control the deformation of the tips 12. If the body 11 is made of composite material, it has a good resistance to compressive forces. On the other hand, the resistance of said body 11 is bad when, in addition to the compression forces, forces in different directions to these compressive forces, such as bending or twisting, act on said body 11. These efforts other than the compression can come for example from the rotation on itself along an axis parallel to the longitudinal axis of the vehicle of the spar 31 impacted by the shock. By deforming, the tips 12 allow to have essentially the compression forces that apply to the body 11, absorbing other efforts.

In addition, these tips 12 also absorb some of the shock, and thus obtain a more gradual increase of the forces on the body 11 and reduce the sudden acceleration by passengers. The floor 2 of FIG. 2 has a central tunnel. The body 11, fixed on the outer surface of the floor 2 relative to the vehicle 3, comprises a central zone 13 traversing an "Ω" shape so as to follow the central tunnel, the two parts of the body 11 around the central zone 13 forming arms 14. This form improves the rigidity of the floor 2 at the tunnel in case of side impact. It also makes it possible to create a zone of rupture programmed thanks to this form in "Ω" when the forces become too important, and thus impose that the body 11 breaks or is deformed in the central zone 13 and not at one of the arms 14.

The central zone 13 of the body 11 lying substantially in the longitudinal and median axis of the vehicle, the arms are substantially under the front passenger seats. In case of significant side impact, the body 11 will break in its central part at the "Ω", but the arms 14 will remain intact. The arms 14 will thus prevent the reduction of the space containing the seats above each of said arms 14, and thus improve the protection of passengers sitting in said seats.

In a variant, the body 11 can be made with the floor 2 and thus be an integral part of said floor 2.

Fig. 4 shows a floor 2 of a vehicle equipped with a cross member 1, the body 11 has an extension 17 in a portion located at the middle of the length of the body 11, and connected to the longitudinal members 31. The extension 17 s' preferably extends towards the rear of the vehicle when the crossbar 1 is fixed on the vehicle. In the case of a floor 2 connected to a heel board, the heel board having a substantially vertical wall inside the vehicle and placed under the seat of the rear seat of the vehicle, the extension 17 is preferably extends at least to the floor portion 2 connected to said heel board. In case of a front impact, the rear fasteners of the front seats generate traction forces on the floor 2 of the vehicle, traction force directed towards the passenger compartment of the vehicle and seeking to lift the floor 2. These traction forces applying to the floor 2 are taken up by the cross 1. The extension 17 allows to transmit these forces from the seats to the heel board and thus increase the resistance of the floor 2 vis-à-vis these traction forces.

Preferably, the width of the extension 17, that is to say its dimension along the transverse axis of the vehicle when the crossbar 1 is installed on the vehicle 2, is greater than the length of the central zone 13, c that is to say the size of the central zone 13 along the transverse axis of the vehicle when the crossbar 11 is installed on the vehicle.

The extension 17 also makes it possible to increase the size of the section of the body 11 at the level of the central zone 13. The capacity of the central zone 13 has withstood the forces in the event of lateral impact is thus improved. Alternatively, the cross member may have several extensions 17. For example, the cross member 1 may comprise two extensions 17 giving the transom a shape in "TT".

The body 11 may comprise reinforcing ribs in the volume defined by its section "U" so as to increase the rigidity of said body 11. During manufacture of the vehicle, the body 11 of the crossbar 1 is fixed on the floor

2. Then the floor 2 is fixed to the side rails 31 of the vehicle structure. Finally, each end piece 12 is positioned between one of the ends of the body 11 and one of the longitudinal members 31, fixed to the body 11 and the spar 31, and thus to the floor 2.

Alternatively, the floor 2 can be first fixed to the longitudinal members 31, then the body of the cross member is fixed to the floor 2. Finally, each end piece 12 is positioned between one of the ends of the body 11 and one of the longitudinal members 31, fixed to the body 11 and the spar 31, and possibly also to the floor 2.

In another variant, the floor 2 is fixed to the longitudinal members 31, then the end pieces 12 are fixed on the body 11, and finally the crossmember 1 is fixed to the floor 2 and to the longitudinal members 31, the ends 12 making the connection between the body 11 and the longitudinal members 31.

Claims

1 / Vehicle undercarriage comprising a floor (2) with a central tunnel extending in a longitudinal direction of the floor (2) and forming an elevation of said floor on the passenger side of the vehicle (3), and a cross member (1) extending between the lateral edges of said floor (2) in a transverse direction perpendicular to the longitudinal direction, the lateral edges being the edges of the floor (2) located along the lateral edges of the vehicle when the floor (2) is installed on the vehicle ( 3), characterized in that said cross member (1) is fixed against the outer surface of the floor (2) located on the outside of the vehicle (3) when the floor (2) is installed on the vehicle, and said crossbar (3) comprises a segment in the middle of its length in a curved "Ω" shape arranged to fit into said tunnel.

2 / Vehicle underbody according to the preceding claim, characterized in that the cross member (2) comprises at least one body (11) of composite material. 3 / Vehicle underbody according to the preceding claim, characterized in that the crosspiece (1) comprises deformable end pieces (12) fixed at least at two ends of said body (11), said end pieces (12) being intended to connect said ends of the body (11). body (11) to elements of the lateral structure of the vehicle (3), in particular to the longitudinal members (31). 4 / Vehicle underbody according to the preceding claim characterized in that the end caps (12) are made of metallic material.

5 / Vehicle underbody according to one of claims 3 or 4, characterized in that the end caps (12) comprise zones of programmed failure.

6 / Vehicle underbody according to one of the preceding claims characterized in that said floor (2) is made of composite material.

7 / vehicle underbody according to one of the preceding claims, characterized in that the cross member (1) comprises at least one extension (17) arranged to extend in a direction parallel to the floor (2) and different from the direction substantially perpendicular to the longitudinal direction of the floor (2). 8 / vehicle (3) comprising a base according to claim 7 characterized in that it comprises a heel board connected to the floor (2), the extension (17) extending to the connection of the floor (2) with said heel board.

9 / A method of manufacturing a vehicle (3) comprising a base according to claim 3 and one of claims 4 to 8, comprising at least the steps of: fixing the body (11) on the floor (2) to form the underbody attachment of the underbody between the lateral structures of the vehicle, in particular between the longitudinal members (31)

attaching the ends (12) at least on the body (11) and an element of the lateral structure of the vehicle.