Energy-absorbing device

Abstract

The invention relates to an energy-absorbing device (1) for a motor vehicle, configured to be arranged between a bumper beam and the end of a motor vehicle side rail facing the bumper beam, the energy-absorbing device (1) extending in a longitudinal direction (L) between the bumper beam and the side rail and having a front end (2) and a rear end (3) opposite one another in the longitudinal direction (L), wherein the energy-absorbing device (1) comprises a body (4) connecting the front end (2) and the rear end (3) and configured to absorb energy in the event of an impact, the body (4) being at least partially made of a material comprising a set of continuous fibres extending in a transverse direction (T) perpendicular to the longitudinal direction (L).

Description

[0001] Description

[0002] TITLE OF THE INVENTION: ENERGY ABSORBING DEVICE

[0003] The present invention relates to the field of energy absorbing devices fitted to motor vehicles. More particularly, the invention relates to energy absorbing devices arranged between an end part of the vehicle and a structural part opposite and set back from the end part and, in particular, at the level of a motor vehicle bumper.

[0004] Energy-absorbing devices in motor vehicles are usually installed between a bumper and a side member of the vehicle. Whether positioned at the front bumper or the rear bumper of the motor vehicle, the function of energy-absorbing devices is to absorb at least part of the energy transferred to the vehicle during potential impacts with external elements. More specifically, energy-absorbing devices prevent this energy from being transmitted entirely to the side members of the vehicle and thus limit their deformation during these impacts, it being understood that replacing a side member, an important structural element of the vehicle's underbody, would require costly operations.

[0005] Such energy absorbing devices can be made with a structure mainly made of a metallic material. However, in order to improve the shock energy absorption properties and reduce pollutant emissions, it is known to have energy absorbing devices composed at least in part of a plastic or composite material. However, the manufacture of such energy absorbing devices can be complex because, depending on the material used, several processes must be implemented successively to obtain the necessary geometries, such as stamping, welding, injection molding, etc.

[0006] Moreover, such metal absorber devices are heavy.

[0007] Plastic or plastic-composite energy-absorbing devices known from the prior art require a significant stroke length to absorb the energy generated during a vehicle impact. Therefore, the volume of these energy-absorbing devices must be large enough to allow sufficient energy absorption, while automobile manufacturers require these energy-absorbing devices to be compact.

[0008] The aim of the invention is therefore to remedy the aforementioned problems and to propose an energy-absorbing device that is easy to manufacture while ensuring sufficient absorption of energy in the event of impacts.

[0009] Another aim of the invention is to propose an energy absorbing device having a reduced volume with equal performance.

[0010] To this end, the subject of the invention is an energy-absorbing device for a motor vehicle, configured to be arranged between an end part of the vehicle and a structural part of the vehicle opposite and set back from the end part in a longitudinal direction L, the energy-absorbing device having a front end and a rear end opposite each other in the longitudinal direction L, the energy-absorbing device comprising a body connecting the front end and the rear end, and configured to absorb energy during an impact, the energy-absorbing device being remarkable in that the body is at least partially made of a material comprising a set of continuous fibers extending in a transverse direction T perpendicular to the longitudinal direction L.

[0011] The energy absorbing device may be arranged at the front of a vehicle or at the rear of a vehicle.

[0012] In particular, the invention relates to an energy-absorbing device for a motor vehicle configured to be arranged between a bumper beam and the end of a side member of a motor vehicle opposite the bumper beam.

[0013] In one embodiment of the invention, the body is manufactured using a process known as "pultrusion," which involves unwinding a roll of continuous fibers before impregnating said fibers, by dipping or injection, in a resin or polymer enveloping the fibers. The soaked fibers are then drawn through a long, heated die that controls the resin content or polymer melting and determines the final shape of the body. The product is then cut to the desired length. The continuous fibers are made, for example, from glass, carbon, or aramid materials.

[0014] The pultrusion process allows for the mass production of profiles with a constant cross-section. In addition, a pultrusion-based energy-absorbing device body offers high performance by absorbing energy over a short length. The volume of the energy-absorbing device is therefore reduced.

[0015] The energy absorbing device according to the invention further comprises at least one of the following characteristics, taken alone or in combination:

[0016] The continuous fibers are encapsulated in a material selected from a thermosetting resin or a thermoplastic polymer.

[0017] The body of the absorber device comprises at least two outer walls connecting the front end and the rear end, and extending in the transverse direction (T), at least one outer wall being at least partially made of a material comprising a set of continuous fibers extending in the transverse direction (T)

[0018] The body further comprises at least one internal wall extending substantially in the longitudinal direction L, the internal wall being arranged between the two external walls and the front and rear ends of the body.

[0019] Each internal wall is at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T.

[0020] The body comprises at least one connecting wall connecting two facing faces respectively of an outer wall and another outer wall or of an outer wall and an inner wall, or of two facing faces of two inner walls, the connecting wall extending in the transverse direction.

[0021] Each connecting wall is at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T.

[0022] The body comprises at least two internal walls, and at least one connecting wall connecting two opposite faces of two internal walls.

[0023] The body comprises two outer walls, at least one inner wall, and at least one connecting wall, said outer, inner, and connecting walls constituting in a plane perpendicular to the direction T a network of cells of closed sections, thus constituting a network of cavities extending in the transverse direction T.

[0024] The outer walls form, in section in a plane perpendicular to the direction T, successions of straight segments and / or segments of curves and / or undulations. The inner walls form, in section in a plane perpendicular to the direction T, successions of straight segments and / or segments of curves and / or undulations.

[0025] The connecting walls form in section in a plane perpendicular to the direction T successions of straight line segments and / or curved and / or undulation segments.

[0026] At least one external and / or internal and / or connecting wall comprises in a direction perpendicular to the transverse direction T a zone of weakness so as to promote a mode of deformation of said wall, the weakness possibly consisting of a local reduction in thickness and / or a groove in a direction substantially perpendicular to the wall, and / or in a localized or extended ribbing along the direction T between two ends of said wall, and / or in a localized or extended depression along the direction T between two ends of said wall in a direction perpendicular to the wall.

[0027] The external and / or internal and / or connecting walls comprise thickness variations in a direction perpendicular to the transverse direction T, said thickness variations being able to be continuous, with a transition element to connect two zones of different thicknesses, or without a transition element.

[0028] The body has variations in its overall width, the width dimension of the body being measured in a direction perpendicular to the longitudinal L and transverse T directions.

[0029] The body has two opposite outer walls, the width dimension is the distance measured in a direction perpendicular to the longitudinal L and transverse T directions, between the outer faces (an outer face being the face of an outer wall not opposite the other outer wall) of the outer walls.

[0030] The width of the body at its front end is different from its width at the rear end.

[0031] The body has an intermediate width different from its width at the front end.

[0032] The body has an intermediate width smaller than its width at the front end and / or smaller than its width at the rear end.

[0033] The width of the body may be identical over its entire extension in the longitudinal direction. The energy absorbing device according to the invention further comprises at least one of the following features, taken alone or in combination:

[0034] - The energy absorbing device comprises fixing walls arranged respectively at its front end and at its rear end, in the longitudinal direction L.

[0035] The attachment walls are configured to attach the energy absorbing device to a front fascia part and to a structural part of the vehicle opposite the front fascia part.

[0036] The attachment walls are configured to attach the forward end of the energy absorbing device to a bumper beam and the rearward end of the energy absorbing device to a vehicle side member.

[0037] The fixing walls are metal plates made from folded or stamped sheet metal, or from foundries.

[0038] The fixing walls are plastic or composite plates overmolded with plastic.

[0039] The fixing walls are ribbed plates.

[0040] The mounting walls can also incorporate other features, such as being predisposed to the attachment of a towing ring.

[0041] The body is connected to the fixing walls by one or more mechanical connections such as a screw-nut system or riveting. The mechanical connections can be reinforced by applying an adhesive which makes it possible to strengthen the aforementioned connection and to block any fibers exposed after the pultrusion process.

[0042] The body is connected to the fixing walls by overmolding.

[0043] The body comprises a front wall disposed at the front of the body, said front wall constituting the front fixing wall.

[0044] The front wall is at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T.

[0045] The body comprises a rear wall disposed at the rear end of the body, said rear end wall constituting the rear fixing wall. The rear wall is at least partially made of a material comprising a set of continuous fibers extending in the transverse direction.

[0046] The front or rear walls are made using a pultrusion process.

[0047] The front or rear walls are made simultaneously with the rest of the body in the same pultrusion process.

[0048] The body includes an overmolding of the front wall and / or the rear wall.

[0049] The front wall and / or the rear wall are configured to fix the energy absorbing device respectively to a front part and to a structural part of the vehicle opposite the front part.

[0050] The front wall and / or the rear wall are configured to secure the front end of the energy absorbing device to a bumper beam and the rear end of the energy absorbing device to a vehicle side member.

[0051] In a configuration for attachment to the front of a vehicle, the front wall of the body of the energy absorbing device constitutes the front end, in the longitudinal direction of the vehicle, of the energy absorbing device, and the rear wall constitutes the rear end of the energy absorbing device.

[0052] In a mounting configuration at the front of a vehicle, the front wall is substantially aligned in the longitudinal direction of the vehicle with the rear wall.

[0053] In a vehicle attachment configuration, the front wall has a transverse offset across the vehicle relative to the rear wall.

[0054] In a vehicle front attachment configuration, the front wall is substantially parallel with a proximal face facing the bumper, and the rear wall is substantially parallel with a proximal face of the side member.

[0055] The energy absorbing device comprises at least one damping element, such as an expanding polyethylene or polyurethane or polystyrene foam.

[0056] The damping element is intended to be inserted into at least one cavity of the body so as to increase the energy absorption capacity during an impact.

[0057] The damping element occupies all the available space in the cavity(ies) that accommodate it, which prevents any liquid or solid material from entering the cavity, for example when overmolding the body to form plastic ribs and interfaces. It is therefore also a filling element.

[0058] The damping element is introduced into the body by material injection.

[0059] The damping element is manufactured beforehand and then mechanically inserted into the body after the body manufacturing step by pultrusion.

[0060] The damping element occupies all the cavities of the body.

[0061] The damping element comprises a support plate connecting at their base all the parts of the damping element which are intended to be inserted into the cavities of the body.

[0062] The energy absorbing device comprises an insert arranged between the front end and the rear end of the energy absorbing device, the insert at least partially surrounding the body.

[0063] Thus, the integration of an insert into the energy-absorbing device advantageously makes it possible to gain in rigidity and to absorb more energy for the same stroke during a crushing phenomenon, that is to say when the front end and the rear end of the energy-absorbing device are brought together,

[0064] The insert can be a composite part added later by gluing or other means of mechanical attachment to the body.

[0065] The insert extends in the longitudinal direction L from the front wall to the rear wall.

[0066] An area of ​​the insert at least partially surrounds the body and is in contact with it.

[0067] The insert includes the damping element.

[0068] The insert is made of at least one material comprising continuous fibers and a thermoplastic resin.

[0069] The insert is at least partially made of a material comprising a set of continuous fibers extending in a substantially longitudinal direction L. Thus, with a body at least partially made of a material comprising a set of continuous fibers extending in the longitudinal direction T and an insert at least partially made of a material comprising a set of continuous fibers extending in the substantially longitudinal direction, the energy absorbing device has a more homogeneous behavior and can absorb more energy, also in different directions.

[0070] The invention also relates to an impact protection assembly for a motor vehicle comprising a front element intended for a vehicle and at least one energy-absorbing device as described above, the energy-absorbing device being intended to be fixed to the structural element, for example the impact protection element comprises a bumper skin, a bumper beam, and at least one energy-absorbing device according to the invention, the energy-absorbing device being intended to be arranged between the bumper beam and a side member of the vehicle. The impact protection assembly is intended to be fixed to the vehicle by the rear wall of the impact-absorbing element to the side member.

[0071] In a particular embodiment of the invention, the impact protection assembly comprises a bumper beam and two energy-absorbing devices spaced transversely from the XZ plane of the vehicle when the assembly is fixed to the vehicle, each energy-absorbing device being intended to be fixed by its rear wall to a side member of the vehicle.

[0072] The invention also relates to a vehicle comprising at least one facade element and one structural element facing and at a distance from the facade element, and at least one energy-absorbing device fixed to the facade element by its front wall and to the structural element by its rear wall. In a particular embodiment of the invention, the vehicle comprises at least one facade element and one structural element facing and at a distance from the facade element, and a plurality of energy-absorbing devices fixed to the facade element by their front wall and to the structural element by their rear wall.

[0073] The invention also relates to a method of manufacturing an energy absorbing device as described previously comprising the following steps:

[0074] - produce the body using a pultrusion process,

[0075] - produce the fixing walls as described above, for example simultaneously with the body in the same pultrusion process. - connect the body to the fixing walls with a mechanical connection when producing the fixing walls separately.

[0076] If necessary, the process also includes the following steps:

[0077] Inserting a damping element into the body cavities and / or Fixing the insert to the body.

[0078] The invention also relates to a method for manufacturing an impact protection assembly comprising the following steps:

[0079] - production of at least one energy-absorbing device of an energy-absorbing device according to the method as described previously, and

[0080] - fixing the absorber device to a front element of the vehicle, for example a bumper or a bumper beam.

[0081] Manufacturing a body using a process called pultrusion also provides the following advantages:

[0082] Absence of corrosion

[0083] High mechanical resistance for a very good mass compromise,

[0084] Very good UV resistance,

[0085] Very good thermal, physicochemical stability,

[0086] Very good resistance to aging.

[0087] DETAILED DESCRIPTION

[0088] Other advantages and characteristics of the present invention will appear more clearly on reading the following description, given for illustrative and non-limiting purposes, and the attached drawings:

[0089] In the detailed description which follows, the invention is represented in the figures in the particular case where the longitudinal direction of the energy absorbing device 1 corresponds substantially to the longitudinal direction X of the vehicle, the transverse direction T of the energy absorbing device corresponds substantially to the vertical direction Z of the vehicle, the shock energy absorbing device 1 being fixed by its front end 2 to a bumper beam 10 arranged at the front of the vehicle and by its rear end 3 to a side member of the vehicle

[0090] The longitudinal direction of the vehicle corresponds to a main direction of extension of the motor vehicle, this longitudinal direction being substantially parallel to the roadway on which the vehicle is intended to travel. The terms "before" and "after" refer to the forward movement of the vehicle. For example, the front end corresponds to an end which is further forward of the vehicle than the rear end.

[0091] The transposition to an arrangement of the energy absorbing element between a rear bumper and a rear side member, sometimes called a side member, makes it possible to improve behavior during an impact at the rear of the vehicle.

[0092] The transposition to an arrangement of the energy-absorbing element between a front facade element and a structural element of the vehicle, the front facade element being arranged higher than the bumper in the vertical Z direction of the vehicle, allows the energy-absorbing device to improve the impact protection of pedestrians outside the vehicle.

[0093] The transverse direction T may in other embodiments of the invention make an angle with the vertical direction Z of the vehicle. In other embodiments of the invention not described below the longitudinal direction L of the energy absorbing device makes an angle with the longitudinal direction X of the vehicle.

[0094] In another particular embodiment, the energy absorbing device is arranged between a vehicle hood and a wing support, the transverse direction T extending substantially in a horizontal plane.

[0095] Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings among which:

[0096] [Fig.l] represents a perspective view of an energy absorbing device 1 according to a first example of the invention;

[0097] [Fig.2] represents a top view of the energy absorbing device 1 of figure 1;

[0098] [Fig.3] is a schematic sectional view in a YZ plane of the body 4 and the damping element.

[0099] [Fig.4] is a schematic sectional view along a YZ plane of the body 4 and the insert 8a, 8b, 8c

[0100] [Fig. 5] is a schematic sectional view of an energy absorbing device 1 according to a second example of the invention.

[0101] [Fig. 6] is a schematic sectional view of an energy absorbing device 1 according to a third example of the invention.

[0102] [Fig. 7] is a schematic top view of a plurality of energy absorbing devices 1 arranged between a front facade element 17 and a structural element 18 at the front of a vehicle.

[0103] [Fig. 8] is a simplified diagram of a pultrusion process.

[0104] The energy absorbing device is hereinafter referred to for brevity as "device" and is designated by the reference 1, as shown in Figure 1.

[0105] The device 1 is configured to be integrated, for example, into a bumper system for a motor vehicle and is in the configuration shown in FIG. 1 arranged between a front bumper beam 10 and the front end of a side member of the vehicle (not shown) opposite the bumper beam 10. This type of energy absorbing device 1 is also known by its English acronym “crashbox” in the automotive field.

[0106] As seen in Figures 1 and 2, the device 1 extends in a substantially longitudinal direction (L), here, between the bumper beam 10 and the side member of a vehicle and has a front end 2 and a rear end 3 opposite each other in the longitudinal direction (L). The device 1 comprises a body 4 connecting the front end 2 and the rear end 3, the body 4 being configured to absorb energy during an impact. The body 4 is at least partially made of a material comprising a set of continuous fibers extending in a direction T transverse to the longitudinal direction L. As shown in Figure 2 or 3, the continuous fibers are substantially oriented in the direction Z, vertical to the vehicle.

[0107] Furthermore, the device 1 comprises at its front end 2 a fixing wall 5 (visible in particular in FIG. 2) capable of receiving fixing means to be fixed to the bumper beam 10, for example by screwing. The device 1 comprises at its rear end 3 a rear fixing wall 6 capable of receiving fixing means to be fixed to the front end of a side member.

[0108] In the example illustrated in Figure 2, the fixing walls 5 and 6 are presented in the form of plates.

[0109] Said plates comprise fixing holes in which screwing means are inserted respectively to the bumper beam and to the side member.

[0110] The plates are in a first embodiment metal plates, ribbed or not.

[0111] The plates are fixed by mechanical means or adhered to the body 4.

[0112] In another embodiment, the plates are made of plastic materials or composite overmolded with plastic, and are fixed by mechanical means or adhered to the body 4.

[0113] In another embodiment, the front 5 and rear 6 walls are at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T perpendicular to the longitudinal direction L, that is to say, in the representation of FIG. 2, that the continuous fibers of the front 5 or rear 6 walls are oriented in the vertical direction Z of the vehicle. The front 5 or rear 6 walls may be made in the form of a plate or plate with ribs and / or at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T.

[0114] In a particular embodiment, the front 5 and rear 6 walls are made in one piece with the body 4, and are manufactured simultaneously with the body 4, by a process called pultrusion.

[0115] As shown in figures 2, 3, 6, the body 4 comprises at least two outer walls 11a, 11b connecting the front end 2 and the rear end 3, each outer wall 11a, 11b being at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T, that is to say that in this representation in figure 2, the continuous fibers of the outer walls 11a, 11b are substantially oriented in the vertical direction Z of the vehicle.

[0116] In the embodiment illustrated in figures 2 or 6 the outer walls 11a, 11b are substantially made in the form of plates, each outer wall 11a, 11b being connected at its front end to the front wall 5 and at its rear end to the rear wall 6. The front walls 5 or rear walls 6 may be made in the form of a plate or plate with ribs and / or at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T.

[0117] In a preferred embodiment, the outer walls 11a, 11b are made in one piece with the front 5 and rear 6 walls, and are manufactured simultaneously with the front 5 and rear 6 walls, by a process called pultrusion.

[0118] In another embodiment, the outer walls 11a, 11b are made separately from the body 4 and are then fixed to the body 4, by mechanical means or by adhesive.

[0119] The body 4 further comprises at least one internal wall 12a extending substantially in the longitudinal direction L, each internal wall being arranged between the two external walls 11a, 11b. In the representation of Figure 2, the body 4 comprises two internal walls 12a, 12b which are arranged between the two opposite external walls 11a, 11b, the internal walls 12a, 12b are shown in Figure 2 being substantially homothetic to the external walls 11a, 11b, the external walls 11a and 11b constituting the lateral ends in the direction Y (oriented transversely relative to the vehicle in running order) of the body 4. The internal walls 12a, 12b are at least partially made of a material comprising a set of continuous fibers extending in the transverse direction T, that is to say in this representation of Figure 2, with an orientation substantially in the vertical direction Z of the vehicle in running order.In the representation of Figure 2, the walls 12a, 12b connect the front 5 and rear 6 walls. Similarly, in the example presented in Figure 6, an internal wall 12a connects the front 5 and rear 6 walls.

[0120] In a preferred embodiment, the inner walls 12a, 12b are made in one piece with the outer walls 11a, 11b and the front 5 and rear 6 walls, and are manufactured together simultaneously by a pultrusion process.

[0121] The body 4 further comprises at least one connecting wall 13 connecting two facing faces of two outer walls 12a or 12b or one face of an outer wall 11a or 11b with a facing face of an inner wall 12a or 12b.

[0122] In the representation of Figure 2, the body 4 comprises two connecting walls 13a, 13b, the connecting walls 13a, 13b being arranged substantially along the vehicle direction Y. Each connecting wall 13a, 13b connects a first outer wall 11a to the closest and facing inner wall 12a, then connects the inner wall 12a to the facing inner wall 12b and then connects the inner wall 12b to the second outer wall 11b, the second outer wall 11b being the wall furthest laterally, in the Y direction, from the first outer wall 11a.

[0123] In one embodiment of the body 4, it comprises a front end wall 5 and a rear end wall 6, two outer walls 11a, 11b, and a plurality of inner walls and a plurality of connecting walls.

[0124] In other words, in a view perpendicular to the direction T, the body 4 comprises a network of cells or alveoli, the walls of which are formed in part by the crossing of the outer walls and / or the inner walls, and / or the connecting walls, and / or the front 5 or rear 6 walls, the sections of which in a plane perpendicular to the direction T are closed, thus constituting cavities extending in the direction T.

[0125] In a preferred embodiment, the body 4, i.e. the walls of the body 4 forming the network of cells or alveoli, are produced simultaneously by a process called pultrusion. Thus, the body 4 is made of a material comprising a set of continuous fibers extending in the transverse direction T.

[0126] In the example given in Figure 2, the continuous fibers are substantially oriented along the vertical Z axis of the vehicle.

[0127] The continuous fibers of the body 4 are in various embodiments, including the preferred embodiment, encapsulated in a material such as a thermosetting resin and a thermoplastic polymer.

[0128] As seen in figures 1 or 2, the body 4 has a substantially rectangular parallelepiped shape.

[0129] Figure 5 represents a schematic view of a second example of an energy absorbing device 1 according to the invention, in which the front wall 5 and the rear wall 6 are substantially parallel, the front wall 5 being longer than the rear wall 6 in a direction P perpendicular to the directions T and L, the body 4 comprising two internal walls 12a and 12b connecting the front wall 5 to the rear wall 6, the body 4 also comprising a connecting wall 13a at right angles to which the body has, in the direction P, a narrower length than at the level of the front 5 and rear 6 walls.

[0130] Figure 6 schematically represents a third example of an energy absorbing device 1 according to the invention, illustrated here according to a section in a plane perpendicular to the direction T, that is to say a plane LP, in which the external walls 11a 11b are curved and of different curvatures.

[0131] In this third example, the body 4 comprises a connecting wall 13a connecting an outer wall 11a to an inner wall 12a and then connecting the wall 12a to the other outer wall 11b. The body 4 comprises a connecting wall 13c connecting the wall 13a to the outer wall 11b without crossing any other walls.

[0132] The body 4 also comprises a connecting wall 13b connecting the outer wall 11a to the inner wall 12a and then connecting the inner wall 12a to the other outer wall 11b. None of the walls 13a, 13b, 13c being parallel in pairs.

[0133] In this example, the inner wall 12a is shown with a curvature inverse to the curvature of the wall 11a.

[0134] The body 4 further comprises an additional wall 14a connecting the connecting wall 13b to the rear wall 6. In this third example, the general shape of the section of the body 4 is curved, that is to say that an intermediate surface located at an equal distance from the external surfaces 11a and 11b has a curved surface. According to the example of Figure 6, in the plane of said section, the curved surface intersects the plane along a curved line C whose concavity is oriented towards the wall 11a.

[0135] In this third example, the body 4 comprising the front 5 and rear 6 walls, the outer walls 11a, 11b, the inner 12a and connecting 13a, 13c, 13b walls, as well as the additional wall 14a, is made in one piece by being manufactured by a pultrusion process in the direction T perpendicular to the directions L and PL. The body 4 is made of at least one material comprising a set of continuous fibers extending in the transverse direction T.

[0136] In the example of figure 2, the outer walls 11, inner walls 12 comprise zones of weakness produced by depressions 15 perpendicular to the wall so as to promote a programmed deformation mode when the front end 2 moves towards the rear end 3 of the energy absorbing device 1, for example during an impact.

[0137] Figure 3 schematically represents another embodiment of the invention in which the energy absorbing device 1 comprises a body 4 comprising three cavities 16, extending in the direction T between the outer walls 11a, 11b, and the closest inner wall 12a, 12b, or between two inner walls 12a, 12b, and connecting the body 4, the energy absorbing device further comprising at least one damping element, such as an expanding foam made of polyethylene or polyurethane or polystyrene, the different parts 7a, 7b, 7c, of the damping element being intended to be inserted into at least one cavity 16 of the body 4 so as to increase the energy absorption capacity when the front end 2 moves towards the rear end 3 of the energy absorbing device 1 during an impact.

[0138] Figure 4 schematically represents an energy absorbing device 1 comprising a body 4 and an insert 8a, 8b, 8c arranged between the front end and the rear end of the energy absorbing device, the insert 8a, 8b, 8c at least partially surrounding the body 4. The insert 8a, 8b, 8c comprises in this representation three plates partially surrounding the body 4 on 3 of its sides. The insert 8a, 8b, 8c is made either of metallic material, or of plastic or composite material, or is at least partially made of a material comprising a set of continuous fibers extending in the direction L perpendicular to the transverse direction T. Thus the insert 8a, 8b, 8c provides reinforcement of the energy absorbing device in the direction L.

[0139] The insert 8a, 8b, 8c may be attached to the body 4 by mechanical means or by adhesive.

[0140] Figure 7 schematically represents, in a section along a horizontal plane XY of the vehicle, a plurality of energy absorbing devices 1 arranged between a facade element 17 and a structural element 18 at the front of a vehicle, the facade element 17 being able to be a front facade of the vehicle or a hood, and in the latter case the energy absorbing device 1 contributes to cushioning an impact between the vehicle and a pedestrian.

[0141] In one embodiment of the invention, an impact protection assembly for a motor vehicle comprises a front element and at least one energy-absorbing device 1, the front element being able to be a bumper skin, connected to a bumper beam and at least one energy-absorbing device 1 according to the invention, the energy-absorbing device 1 being fixed to the bumper beam and being intended to be fixed by its rear end 3 to a structural element of the vehicle.

[0142] Figure 8 schematically illustrates a pultrusion manufacturing process, comprising:

[0143] - a first step E1 of passing the continuous fibers through compression rollers to agglomerate one or more layers of continuous fibers, and to drive the layers of continuous fibers,

[0144] - a second step E2 of tensioning and training the continuous fibers,

[0145] - a third step E3 of coating the continuous fibers in a resin, for example in a bath,

[0146] - a fourth cooking step E4,

[0147] - a fifth stretching step E5

[0148] - and finally a sixth step, not shown, of cutting to obtain the finished product. The direction of extension of the continuous fibers corresponds to the direction of drive of the continuous fibers by the rollers, the continuous fibers being encapsulated following the third step in a material chosen for example from a thermosetting resin and / or a thermoplastic polymer.

[0149] Continuous fibers are, for example, made from glass or carbon materials.

[0150] Of course, the description of the invention is not limited to the embodiments described above and to the field described above.

Claims

Claims

1. Energy absorbing device (1) for a motor vehicle, configured to be arranged between a front end part of the vehicle and a structural part of the vehicle facing and set back from the front end part in a longitudinal direction (L), for example configured to be arranged between a bumper beam (10) and the end of a side member of a motor vehicle facing the bumper beam (10), the energy absorbing device (1) having a front end (2) and a rear end (3) opposite each other in the longitudinal direction (L) and comprising a body (4) connecting the front end (2) and the rear end (3), configured to absorb energy during an impact, characterized in that the body (4) is at least partially made of a material comprising a set of continuous fibers extending in a transverse direction (T) perpendicular to the longitudinal direction (L).

2. Energy absorbing device (1) according to claim 1 wherein the body (4) comprises at least two outer walls (11, 11a, 11b) connecting the front end (2) and the rear end (3), and extending in the transverse direction (T), each outer wall (11) being at least partially made of a material comprising a set of continuous fibers extending in the transverse direction (T).

3. Energy absorbing device (1) according to claim 2 wherein the body (4) further comprises at least one first internal wall (12a, 12b) arranged between the two external walls (11), the internal wall (12a, 12b) being connected to the front end (2) and / or to the rear end (3), the internal wall (12a, 12b) being at least partially made of a material comprising a set of continuous fibers extending in the transverse direction (T).

4. Energy absorbing device (1) according to the preceding claim in which the body (4) comprises at least one connecting wall (13a, 13b, 13c) connecting two facing faces of two outer walls (11a, 11b) and / or one face of an outer wall (11a, 11b) with a facing face of an inner wall (12a, 12b), the connecting wall (13) being at least partially made of a material comprising a set of continuous fibers extending in the transverse direction (T).

5. Energy absorbing device (1) according to the preceding claim, in which the two outer walls (11a, 11b), the inner wall(s) (12a, 12b) and the connecting wall(s) (13) form a network of cells or alveoli whose sections in a plane perpendicular to the direction T are closed, thus constituting cavities extending in the direction (T).

6. Energy absorbing device according to one of the preceding claims wherein the body (4) comprises fixing walls (5, 6) arranged respectively at the front end (2) and the rear end (3), the fixing walls (5, 6) being configured to fix the energy absorbing device (1) to a front end part of the vehicle and to a structural part of the vehicle, for example to a bumper beam (10) and to one end of a side member of a motor vehicle opposite and facing the bumper beam (10), preferably the front wall (5) and / or the rear wall (6) are at least partially made of a material comprising a set of continuous fibers extending in the transverse direction (T),

7. Impact protection assembly for a motor vehicle comprising a front element intended for a vehicle and at least one energy absorbing device (1) according to one of claims 1 to 7, the energy absorbing device being intended to be fixed to a structural element of the vehicle, preferably the impact protection assembly comprises a bumper skin, a bumper beam (10) and at least one energy absorbing device (1) according to one of claims 1 to 7, the energy absorbing device (1) being intended to be fixed to a side member of the vehicle by its rear end (3).

8. Motor vehicle comprising a facade element, a structural element arranged set back and facing the facade element, the motor vehicle further comprising an energy absorbing device (1) according to one of the preceding claims 1 to 7, the energy absorbing device (1) being fixed at its front end (2) to the facade element and at its rear end (3) to the structural element.

9. A method of manufacturing a shock absorbing device (1) according to one of claims 1 to 7, wherein the method comprises at least one step of manufacturing the body (4) by a pultrusion method.

10. Energy absorbing device according to the preceding claim in which the walls (4, 5, 11a, 11b, 12a, 12b, 13a, 13b, 13c, 14) constituting the body (4) are made in one piece by being manufactured simultaneously by a so-called pultrusion process.

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