Bumper cross member

Abstract

The invention relates to a bumper crossmember (5) intended to be fixed to rear axle chocks of a motor vehicle. The bumper crossmember (5) according to the invention comprises an impact beam (10) and two impacting chocks (11). The impact beam (10) is intended to extend laterally between the rear axle chocks of the motor vehicle. Each impacting chock (11) is located at a longitudinal end (12) of the impact beam (10), and each impacting chock (11) is configured to be fixed integrally to one of the rear axle chocks. Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Bumper crossmember

[0001] The technical context of the present invention is that of the structural elements which make up the rear of motor vehicles, and more particularly of the so-called "passive safety" rear motor vehicle elements used to protect said motor vehicle from rear impacts which it is likely to suffer. More particularly, the invention relates to a bumper crossmember.

[0002] In the state of the art, rear motor vehicle structural elements are known that are configured to improve the safety of the motor vehicle and its occupants in the event of an impact applied to the rear of the motor vehicle. These structural elements must meet automotive crash test standards. In particular, these structural elements are designed to meet the rear impact protocol "80 kph / NHTSA barrier 1368 kg / 70% overlap". This protocol, also called "barrier test", is a high intrusion protocol implementing a standardized rear impact barrier striking the rear of the motor vehicle. The rear impact barrier used in this protocol is composed of two main elements: a body 101 and a bumper, the bumper being lower than the body 101 of the rear impact barrier, integral with the body 101 of the rear impact barrier and projecting from the body 101 of the rear impact barrier.The rear impact barrier bumper has a greater stiffness than the rear impact barrier body 101 - 245 psi and 45 psi, respectively. The rear impact barrier bumper is oriented, in the high intrusion protocol, forward of the barrier body 101.

[0003] Structural elements of a motor vehicle are known which make it possible to absorb a force due to an impact in order to secure the motor vehicle and its occupants. Among these structural elements, it is known to equip the rear of the motor vehicle with a rear bumper fixed securely to two rear side rails of a chassis of the motor vehicle. When a rear impact is applied to the motor vehicle, the rear bumper deforms and absorbs the force due to the impact in order to limit damage to the rear of said motor vehicle.

[0004] The disadvantage of rear bumpers is that they have a deleterious effect when the motor vehicle they equip is subjected to the high intrusion protocol described above. Indeed, when this protocol is applied, it is very difficult to maintain stable bumper / rear bumper contact. Indeed, the bumper of the rear impact barrier tends to strike the rear bumper of the motor vehicle in its lower part. Then, the rear bumper of the motor vehicle tilts and lifts the side rails. As a result, on the one hand, the rear bumper of the motor vehicle strikes and tears the body of the rear impact barrier, which is less rigid than the bumper of the rear impact barrier. As a result, on the other hand, the bumper of the rear impact barrier hits other rear elements in the motor vehicle, such as an exhaust muffler and / or a rear axle of the motor vehicle. Thus, these rear bumpers fixed integrally to the side rails offer clearly insufficient protection for collisions similar to the high intrusion protocol, whether for the integrity of the motor vehicle or the safety of its occupants.

[0005] Structural elements of a motor vehicle are also known which make it possible to transmit a force due to the impact in order to secure the motor vehicle and its occupants. Among these structural elements, it is known to equip the rear of the motor vehicle with a bumper crossmember which stiffens the rear of the motor vehicle and which is fixed securely to two rear side rails of a chassis of the motor vehicle. When a rear impact is applied to the motor vehicle, the bumper crossmember, being rigid, transmits the force due to the impact to the rear side rails. The transmission of this force has the objective of actuating the rear wheels to set the motor vehicle in motion forwards, in order to limit damage to the rear of said motor vehicle.

[0006] The disadvantage of bumper crossmembers intended to be fixed integrally to the rear side rails of the motor vehicle is that, by being fixed integrally to the side rails, they transmit the impact force to the wheels of the motor vehicle in a suboptimal manner. They thus provide little satisfaction in setting in motion the motor vehicle they equip subjected to the high-intrusion protocol described above.

[0007] Motor vehicles are also known which are equipped with a second rear bumper for a motor vehicle, positioned forward and lower than the aforementioned conventional rear bumper. This second rear bumper for a motor vehicle makes it possible, when applying the high intrusion protocol, to provide stable support for the bumper allowing the motor vehicle to be set in motion. Even if it protects the rear elements in the motor vehicle, this second rear bumper for a motor vehicle, formed of steel, has the disadvantage of weighing down the structure of the motor vehicle.

[0008] The object of the present invention is to propose a new bumper crossmember in order to address at least a large part of the above problems and to further lead to other advantages.

[0009] Another object of the invention is to provide a bumper crossmember for a motor vehicle which is reliable in its operation.

[0010] Another object of the invention is to propose a bumper crossmember for a motor vehicle configured to reduce the severity of a high-intrusion rear impact at the level of the motor vehicle it equips.

[0011] Another object of the invention is to propose a bumper crossmember for a motor vehicle configured to satisfy the rear impact protocol "80 kph / NHTSA barrier 1368 kg / 70% overlap".

[0012] Another object of the invention is to propose a bumper crossmember for a motor vehicle that is not very massive, so as not to negatively impact the mass of the motor vehicle.

[0013] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a bumper crossmember intended to be fixed to rear axle chocks of a motor vehicle, the bumper crossmember comprising (i) an impact beam intended to extend laterally between the rear axle chocks of the motor vehicle, (ii) two impacting chocks, each impacting chock being located at a longitudinal end of the impact beam, each impacting chock being configured to be fixed integrally to one of the rear axle chocks.

[0014] The bumper crossmember according to the first aspect of the invention is intended to transmit to a structural element of a motor vehicle equipped with said bumper crossmember an impact applied to the rear of said motor vehicle. The bumper crossmember according to the first aspect of the invention is intended to resist deformation induced by a force following the impact. It is understood that the bumper crossmember according to the invention is configured to have a rigidity protecting it from mechanical deformation due to the impact.

[0015] In the bumper crossmember according to the first aspect of the invention, the impact beam connects the impact wedges to each other. Advantageously, the impact wedges are symmetrical to each other with respect to a vertical median plane of the bumper crossmember according to the invention.

[0016] In the bumper crossmember according to the first aspect of the invention, the impact beam makes it possible to increase a contact surface between the motor vehicle equipped with the bumper crossmember according to the invention and an object striking the rear of said motor vehicle. The impact beam is intended to stiffen the rear of the motor vehicle, in particular in front of a rear bumper of the motor vehicle.

[0017] When an impact is applied to the rear of the motor vehicle equipped with the bumper crossmember according to the invention, the impact beam is struck. When it is implemented, the impact beam transmits a force due to the impact to the two impact wedges. By each being fixed integrally to one of the rear axle wedges of the motor vehicle equipped with the bumper crossmember according to the invention, the impact wedges transmit to each of said rear axle wedges the force due to the impact coming from the impact beam. Then, the rear axle wedges transmit to a rear axle of the motor vehicle, and therefore to the wheels of the motor vehicle, the force due to the impact. Thus, the force due to the impact transmitted to the wheels of the motor vehicle naturally sets the motor vehicle in motion forwards.

[0018] Such a bumper crossmember, intended to be fixed securely to the rear axle chocks of the motor vehicle, makes it possible to satisfy the rear impact protocol "80 kph / NHTSA barrier 1368 kg / 70% overlap", also called "barrier test". Thus, this solution makes it possible to preserve the integrity of the motor vehicle with which it is fitted during the application of the high intrusion protocol. It offers stable support between the impact beam and a rear impact barrier implemented in the barrier test, in particular at a lower part of the barrier, thus making it possible to set the motor vehicle in motion more quickly by means of the impacting chocks. The bumper crossmember according to the invention has the advantage of overcoming the drawbacks mentioned above, without negatively impacting the mass of the motor vehicle with which it is fitted.

[0019] The bumper crossmember according to the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0020] - each impact wedge has a housing intended to partially house the wedge of rear axle to which it is securely attached. Housed in the impact wedge housing, the rear axle wedge is protected in the event of an impact;

[0021] - each impact wedge takes a cylindrical shape. An impact wedge of shape cylindrical improves the distribution of a force imposed during a barrier test or during any equivalent force applied to the bumper crossmember according to the invention. In particular, during the barrier test, the cylindrical shape of the impact wedge makes it possible to maintain contact between the rear impact barrier and the impact wedge, and this throughout the impact. An operating efficiency of the rear impact barrier is maximum. Advantageously, a base of the impact wedge is circular;

[0022] - the impact beam comprises, on at least one of its faces, stiffening ribs- The stiffening ribs are configured to enhance the robustness to mechanical forces that may be imposed on the impact beam. In particular, the stiffening ribs are configured to enhance the robustness of the impact beam with respect to a force equivalent to the force imposed during the barrier test. The stiffening ribs project from at least one of the faces of the impact beam

[0023] - the stiffening ribs are located on one face of the impact beam intended to be located opposite the rear axle shims. In other words, the stiffening ribs are located on a front face of said impact beam;

[0024] - the stiffening ribs extend longitudinally between the two im- patrices. Such longitudinal extension stiffening ribs further reinforce the robustness to the mechanical forces that may be imposed on the impact beam during the barrier test;

[0025] - according to a first exemplary embodiment of the invention, the impact beam is delimited longitudinally by two longitudinal edges and extends between the two impact wedges, the impact beam being formed by a solid flange. It is understood that an impact beam formed by a solid flange has a constant and homogeneous section. Such an impact beam formed by a solid flange reinforces the rigidity of the impact beam. For example, the solid flange forming the impact beam is formed by a shaped sheet metal;

[0026] - according to a second exemplary embodiment of the invention distinct from the first exemplary embodiment of the invention, the impact beam is delimited longitudinally by two longitudinal edges and extends between the two impact wedges, each longitudinal edge having a front flap, so that the impact beam has a C-shaped cross-section. The front flaps extend in front and / or behind the front face of the impact beam. The front flaps reinforce the robustness of the impact beam in the face of mechanical forces that may be imposed on it, while ensuring the lightness of said impact beam. Advantageously, the front flap is intended to be located opposite the rear axle wedges. In such a configuration, the impact beam makes it possible to encase an exhaust silencer of the motor vehicle mounted in front of the bumper crossmember according to the invention.The exhaust silencer is maintained despite a rear impact and deforms following said rear impact, playing the role of shock absorber, completing the security provided by the bumper crossmember according to the invention;

[0027] - according to a third exemplary embodiment of the invention, distinct from the first exemplary embodiment of the invention and of the second exemplary embodiment of the invention, the impact beam is delimited longitudinally by two longitudinal edges and extends between the two impacting wedges according to a honeycomb structure. It is understood that such an impact beam has a profile having at least one closed cell, advantageously several closed cells. The honeycomb structure reinforces the robustness of the impact beam in the face of mechanical forces which may be imposed on it, while ensuring the lightness of said impact beam;

[0028] - in the third variant embodiment of the invention, the alveolar structure has a plurality of partitions extending longitudinally between the two impact wedges, the partitions being adjacent to each other between the two longitudinal edges of the impact beam;

[0029] - according to a first embodiment, the impact beam is made from material with the impact wedges. The term "made in one piece" means that, in the bumper crossmember according to the first aspect of the invention, the impact beam and the impact wedges cannot be separated from each other without damaging all or part of their integrity. Thus, in the bumper crossmember according to the invention, the impact beam and the impact wedges form an assembly described as monobloc because together they form only one continuous piece, made from a single piece and obtained during the same manufacturing process. The invention according to its first aspect thus advantageously makes it possible to obtain a prefabricated bumper crossmember, the manufacturing of which is simplified since it eliminates the need to assemble the impact beam and the impact wedges, as well as the presence of fixing means between the impact beam and the impact wedges.In addition, a one-piece bumper crossmember can be machined in a variety of different dimensions so as to be adapted to different models of motor vehicles. Such a bumper crossmember is also more rigid and lighter. For example, the impact beam and the impact wedges are produced using the same molding process. This industrial forming process makes it possible to obtain a large number of identical units at a lower cost by repeating the use of the same mold. According to a second alternative embodiment to the first embodiment, the impact beam is attached to each of the impact wedges. In the case where the impact beam is attached to each of the impact wedges, the impact beam is for example fixed integrally to each of the impact wedges by means of detachable fixing means, such as for example by screwing.Alternatively or additionally, the impact beam is fixed securely to each of the impact wedges by means of definitive fixing means, such as for example by gluing and / or by welding; .

[0030] - the impact beam is formed from a first material and the impact wedges are formed of a second material different from the first material. Alternatively, the impact beam and the impact wedges are formed of the same material;

[0031] - the impact beam is formed from a shaped steel sheet;

[0032] - a thickness of the steel sheet forming the impact beam is less than 3 mm, preferably between 1 and 1.5 mm;

[0033] - the impact beam is formed from a composite material comprising a load in fibers. Such a fiber-filled composite material has enhanced mechanical properties of resistance to deformation. For example, the fiber-filled composite material forming the impact beam includes a glass fiber filler and / or a carbon fiber filler. For example, the composite material is of the SMC type, for the English acronym "Sheet Molding Compound", or of the BMC type, for the English acronym "Bulk Molding Compound".

[0034] According to a second aspect of the invention, there is provided a motor vehicle comprising (i) a structural element of the motor vehicle comprising side rails and rear axle wedges, (ii) a rear bumper fixed integrally to the side rails, (iii) a bumper crossmember according to the first aspect of the invention or according to any of its improvements, the bumper crossmember being fixed integrally to the rear axle wedges.

[0035] In the motor vehicle according to the second aspect of the invention, the bumper crossmember is intended to transmit to the structural element an impact applied to the rear of said motor vehicle. The bumper crossmember according to the first aspect of the invention is intended to resist deformation induced by a force induced by the impact. It is understood that the bumper crossmember according to the invention is configured to have a rigidity protecting it from mechanical deformation due to the impact.

[0036] When an impact is applied to the rear of the vehicle according to the second aspect of the invention, the impact beam is struck. When it is implemented, the impact beam transmits a force due to the impact to the two impacting wedges. By each being fixed integrally to one of the rear axle wedges of the motor vehicle according to the invention, the impacting wedges transmit to each of said rear axle wedges the force due to the impact coming from the impact beam. Then, the rear axle wedges transmit to a rear axle of the motor vehicle the force due to the impact, naturally setting the motor vehicle in motion.

[0037] Such a motor vehicle makes it possible to satisfy the rear impact protocol “80 kph / NHTSA barrier 1368 kg / 70% overlap”, also called “barrier test”. Thus, this solution makes it possible to preserve the integrity of the motor vehicle during the application of the high intrusion protocol, by providing stable support at the impact beam of the bumper crossmember and making it possible to set the motor vehicle in motion via the impacting wedges. The motor vehicle according to the invention has the advantage of overcoming the drawbacks mentioned above, without having a negatively impacted mass.

[0038] The motor vehicle in accordance with the second aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0039] - the bumper crossmember is separate from the rear bumper. It is understood that the The crossmember and the rear bumper are two clearly distinguishable entities. The bumper crossmember and the rear bumper are also different in shape and size. In addition, the rear bumper is intended to dissipate an impact while the bumper crossmember is intended to transmit it to set the vehicle in motion. motor vehicle according to the invention;

[0040] - the bumper crossmember is fixed further forward than the rear bumper. Thus, during an impact applied to the rear of the motor vehicle according to the second aspect of the invention, the rear bumper is likely to be struck first and the bumper crossmember second;

[0041] - the bumper crossmember is located vertically below the rear bumper, in an intermediate position between the rear bumper and a rolling surface of the motor vehicle. Such a configuration makes it possible to advantageously protect the motor vehicle from deformation during the barrier test. During a barrier test, the bumper of the rear impact barrier is advantageously likely to strike only the bumper crossmember;

[0042] - the bumper crossmember is fixed securely to each of the rear axle wedges by means of its impact shims. In particular, the bumper crossmember is securely attached to each of the rear axle shims by means of fixing screws passing through the impact shims and housed in the rear axle shims.

[0043] Various embodiments of the invention are provided, integrating according to all of their possible combinations the different optional characteristics set out here.

[0044] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0045] [fig. 1] illustrates a schematic view of a motor vehicle according to the second aspect of the invention;

[0046] [fig.2] illustrates a schematic view of a bumper crossmember conforming to the first aspect of the invention in a first variant embodiment;

[0047] [fig.3] illustrates a schematic view of the bumper crossmember conforming to the first aspect of the invention in a second variant embodiment;

[0048] [fig.4] illustrates a schematic view of the bumper crossmember conforming to the first aspect of the invention in a third variant embodiment;

[0049] [fig.5] illustrates a schematic view of the bumper crossmember conforming to the first aspect of the invention in a fourth variant embodiment;

[0050] [fig.6] illustrates a schematic view of the bumper crossmember conforming to the first aspect of the invention in a fifth variant embodiment;

[0051] [fig.7] illustrates a schematic view of the bumper crossmember conforming to the first aspect of the invention in a sixth variant embodiment;

[0052] [fig.8] illustrates the bumper crossmember according to the first aspect of the invention shown in [fig.2] cooperating with a rear axle wedge of the motor vehicle;

[0053] [fig.9] illustrates an implementation of the motor vehicle in accordance with the second aspect of the invention.

[0054] Of course, the features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0055] In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

[0056] In the figures, the elements common to several figures retain the same reference.

[0057] [fig.l] illustrates a motor vehicle 1 according to the second aspect of the invention, seen from below. In the remainder of the description, a reference frame is defined in which a longitudinal axis OX, a transverse axis OY and a vertical axis OZ are defined. The longitudinal axis OX corresponds to a trajectory of the motor vehicle 1 when it is moving forward, in a straight line and on a flat road. The longitudinal axis OX corresponds to a direction going from the front to the rear of the motor vehicle 1, and it is oriented from the front to the rear of the motor vehicle 1. A longitudinal direction parallel to the longitudinal axis OX is also defined, the adjectives “front”, “rear” or “frontal” refer to this reference direction, as does the term “length”.The transverse axis OY corresponds to the axis around which wheels 40 of the motor vehicle 1 rotate, and the direction of the axis OY is oriented from a passenger side to a driver side, in the non-Anglo-Saxon standard. A transverse direction parallel to the transverse axis OY is also defined, and the adjectives “lateral” or “transverse” refer to this reference direction, as does the term “width”. The vertical axis OZ is an axis perpendicular simultaneously to the axis OX and to the axis OY, and which is oriented from a floor of the motor vehicle 1 to a roof of said motor vehicle 1, the adjectives “upper” and “lower” refer to this reference direction, as does the term “height”.

[0058] In [fig.l], only a rear part 2 of the motor vehicle 1 according to the second aspect of the invention is shown in detail. The motor vehicle 1 comprises a structural element 3, a rear bumper 4 and a bumper crossmember 5 according to the first aspect of the invention. The bumper crossmember 5 is separate from the rear bumper 4 and is mounted in front of the rear bumper 4. The bumper crossmember 5 according to the invention is symmetrical with respect to a vertical median plane 6 of said bumper crossmember 5 according to the invention, the vertical median plane 6 extending in the longitudinal direction and being merged with a median longitudinal extension axis 7 of the motor vehicle 1.

[0059] [fig.l] shows that the structural element 3 of the motor vehicle 1 comprises side rails 8 and rear axle wedges 9. The rear bumper 4 and the bumper cross member 5 according to the invention are both fixed integrally to a separate part of the structural element 3 of the motor vehicle 1. The rear bumper 4 is fixed integrally to the side rails 8 of the structural element 3 of the motor vehicle 1. The bumper cross member 5 is fixed integrally to the rear axle wedges 9 of the structural element 3 of the motor vehicle 1.

[0060] [Fig. 1] shows that the bumper crossmember 5 comprises an impact beam 10 and two impact wedges 11 each located at one of the longitudinal ends 12 of the impact beam 10. The impact beam 10 extends laterally between the rear axle wedges 9 of the motor vehicle 1. In the bumper crossmember 5 according to the invention, the impact beam 10 extends between the two impact wedges 11 and along a transverse axis 13. The two impact wedges 11 are mounted forward relative to the transverse axis 13 of the impact beam 10. Each impact wedge 11 is fixed integrally to one of the rear axle wedges 9. [Fig. 8] illustrates a close-up view of the bumper crossmember 5 according to the first aspect of the invention shown in [Fig. 2], detailing the cooperation between the rear axle wedge 9 and the impact wedge 11 of the bumper crossmember 5 of the motor vehicle 1.

[0061] [fig.l] shows that the motor vehicle 1 comprises an exhaust silencer 14 behind the bumper crossmember 5. The exhaust silencer 14 is embedded in the impact beam 10 of said bumper crossmember 5. The impact beam 10 of the bumper crossmember 5 according to the invention comprises a front face 15, oriented opposite the rear axle chocks 9 and towards the exhaust silencer 14 of the motor vehicle 1. The impact beam 10 of the bumper crossmember 5 according to the invention comprises a rear face 16 opposite the front face 15 of the impact beam 10. The rear face 16 of the impact beam 10 is oriented towards the rear bumper 4 of the motor vehicle 1.

[0062] The motor vehicle 1 further comprises a fuel tank 17. It is understood that the motor vehicle 1 shown is a thermal vehicle, but the invention extends to motor vehicles of the electric and / or hybrid type. The motor vehicle 1 according to the second aspect of the invention is for example of the BEV type for the English acronym Battery Electric Vehicle, equipped with an electric motor. The motor vehicle 1 according to the second aspect of the invention is for example of the PHEV type, for the English acronym Plug-in Hybrid Electric, equipped with both a thermal engine and an electric engine.

[0063] With reference to FIGURES 2 to 7, different variant embodiments of the bumper crossmember 5 according to the first aspect of the invention are illustrated. Only one of the longitudinal ends 12 of the impact beam 10 and one of the two impact wedges 11 associated with it are shown, but it is understood that the bumper crossmember 5 according to the first aspect of the invention is identical on either side of the vertical median plane 6 of the bumper crossmember 5 according to the invention as shown in [fig.l]. The transverse axis 13 of the impact beam 10 is shown.

[0064] FIGURES 2 to 7 show that the impact wedge 11 takes a cylindrical shape having a circular upper base 18 opposite a circular lower base 19, and an internal wall 20 opposite an external wall 21. The impact wedge 11 comprises a body 22 which extends along a vertical axis 23 substantially perpendicular to the transverse axis 13 of the impact beam 10 and in front of the transverse axis 13 of the impact beam 10. The impact wedge 11 comprises a housing 24 intended to partially house the rear axle wedge 9. The housing 24 comprises a central space 25 centered on the vertical axis 23 of the impact wedge 11, the central space 25 being delimited by the internal wall 20 of the body 22 of the impact wedge 11. [fig.2] shows in particular that the central space 25 of the housing 24 is delimited by a central sleeve 50 centered on the vertical axis 23 of the impacting wedge 11 and by a transverse wall 51 forming a bottom of the central space 25 of the housing 24.[Fig.8] shows that the central sleeve 50 is intended to cooperate with the rear axle wedge 9 bearing against the transverse wall 51.

[0065] FIGURES 2 to 7 show that the housing 24 comprises a peripheral space 26 formed in the body 22 of the impact wedge 11 behind the impact beam 10, between the internal wall 20 and the external wall 21 of the impact wedge 11. The peripheral space 26 of the housing 24 extends vertically between the upper base 18 of the impact wedge 11 and the transverse axis 13 of the impact beam 10.

[0066] In the variant embodiments of the bumper crossmember 5 according to the invention illustrated in FIGURES 2 to 7, the impact beam 10 is delimited longitudinally by two longitudinal edges 27. Each longitudinal edge 27 of the impact beam 10 has a front flap 28.

[0067] In the alternative embodiment of the bumper crossmember 5 according to the invention illustrated in [fig.2], 6 and 7, the impact beam 10 comprises stiffening ribs 29 on its front face 15 extending longitudinally between the two impacting wedges 11. In particular in the alternative illustrated in [fig.2], stiffening ribs 29 extend from one longitudinal end 12 to the other.

[0068] In the alternative embodiment of the bumper crossmember 5 according to the invention illustrated in [fig.4], 5, 6 and 7, the impact beam 10 comprises a stiffening rib- attachment 29 on its front face 15 extending vertically between the two longitudinal edges 27.

[0069] In the alternative embodiments of the bumper crossmember 5 according to the invention illustrated in [fig.3] and 4, the impact beam 10 is formed by a flange 30. In [fig.3], the flange 30 forming the impact beam 10 has a uniform height between the two impact wedges 11, the longitudinal edges 27 of the impact beam 10 extend to the same height as the bases 18, 19 of the impact wedge 11. In [fig.4], the flange 30 forming the impact beam 10 comprises a central portion 31 narrower than a lateral portion 32 connecting the central portion 31 to the impact wedge 11. The lateral portion 32 has longitudinal edges 27 which extend to the same height as the bases 18, 19 of the impact wedge 11. The central portion 31 extend between the longitudinal edges 27 of the lateral part 32 at the level of the transverse axis 13 of the impact beam 10.

[0070] In the alternative embodiments of the bumper crossmember 5 according to the invention illustrated in [fig.6] and 7, the impact beam 10 has a honeycomb structure 33. The honeycomb structure 33 of the impact beam 10 of the bumper crossmember 5 illustrated in [fig.6] has a single cell 55 projecting from the rear face 16 of the impact beam 10. The honeycomb structure 33 of the impact beam 10 of the bumper crossmember 5 illustrated in [fig.7] has a plurality of partitions 34 which extend longitudinally between the two impacting wedges 11, the partitions 34 being adjacent to each other between the two longitudinal edges 27 of the impact beam 10.

[0071] The embodiment variant illustrated in [fig.3] is advantageously formed from steel or composite materials. The embodiment variants illustrated in FIGURES 4 and 5 are advantageously formed from steel and / or composite materials, for example with an impact wedge 11 formed from composite material and a flange 30 formed from a thin sheet. The embodiment variants illustrated in FIGURES 6 and 7 are advantageously formed from a composite material.

[0072] [Fig. 8] shows that the bumper crossmember 5 is securely attached to the rear axle wedge 9 by means of the impact wedge 11. The rear axle wedge 9 of the motor vehicle 1 is engaged in the housing 24 of the impact wedge 11, both in the central space 25 of the housing 24 and in the peripheral space 26 of the housing 24. The bumper crossmember 5 is securely attached to the rear axle wedge 9 by means of fixing screws 35 passing through the impact wedge 11 and being housed in the rear axle wedge 9. The fixing screw 35 is coaxial with the vertical axis 23 of the impact wedge 11 and is housed in the central sleeve 50.

[0073] [Fig. 9] illustrates, seen from below, an implementation of the motor vehicle 1 in accordance with the second aspect of the invention in a barrier test, otherwise called the rear impact protocol “80 kph / NHTSA barrier 1368 kg / 70% overlap”.

[0074] [Fig.9] shows a standardized rear impact barrier 100 striking the rear of the motor vehicle 1 according to a strong intrusion characterizing the barrier test. The rear impact barrier 100 is composed of two main elements: a body 101 and a lower bumper 102 secured to the body 101 of the rear impact barrier 100 and projecting and in front of said body 101. The bumper 102 of the rear impact barrier 100 has a significant rigidity compared to the body 101 of the rear impact barrier 100. [fig.9] shows that the bumper crossmember 5 according to the first aspect of the invention has a large contact surface with the bumper 102 of the rear impact barrier 100.

[0075] A first insert 901 of [fig.9] shows that the rear impact barrier 100 strikes the rear of the motor vehicle 1 in a direction going from rear to front, as illustrated by an arrow 36. The rear bumper 4 of the motor vehicle 1 is not illustrated in [fig.9] but it is understood that the latter is at a height such that it is not struck by the bumper 102 of the rear impact barrier 100.

[0076] In the first insert 901 of [fig.9], the bumper 102 of the rear impact barrier 100 comes into contact with the impact beam 10 of the bumper crossmember 5 according to the invention. In a second insert 902 of [fig.9], the rear impact barrier 100 has continued its progression towards the front of the motor vehicle 1, and it deforms as shown by the plurality of arrows 37. A front surface 103 of the bumper 102 of the rear impact barrier 100 is exploited to the maximum, the bumper crossmember 5 according to the invention offering a large contact surface with said bumper 102. Simultaneously, the exhaust silencer 14 remains held by the bumper crossmember 5 according to the invention in which it is embedded. The cylindrical shape of the impact wedge 11 makes it possible to maintain contact with the rear impact barrier 100 throughout the impact, allowing for maximum operating efficiency of said rear impact barrier 100.The force due to the impact is transmitted to the rear axle shims 9, as shown by a first solid arrow 39, which causes the motor vehicle 1 to move, as shown by a second solid arrow 4L.

[0077] In summary, the invention relates to a bumper crossmember 5 intended to be fixed to rear axle chocks 9 of a motor vehicle 1. The bumper crossmember 5 according to the invention comprises an impact beam 10 and two impacting chocks 11. The impact beam 10 is intended to extend laterally between the rear axle chocks 9 of the motor vehicle 1. Each impacting chock 11 is located at a longitudinal end 12 of the impact beam 10, and each impacting chock 11 is configured to be fixed integrally to one of the rear axle chocks 9.

[0078] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, forms, variants and embodiments of the invention can be associated with each other according to various combinations to the extent that they are not incompatible or mutually exclusive. In particular, all the variants and embodiments described above can be combined with each other.

Claims

Claims

1. Bumper crossmember (5) intended to be fixed to rear axle chocks (9) of a motor vehicle (1), the bumper crossmember (5) comprising: - an impact beam (10) intended to extend laterally between the rear axle chocks (9) of the motor vehicle (1); - two impacting chocks (11), each impacting chock (11) being located at a longitudinal end (12) of the impact beam (10), each impacting chock (11) being configured to be fixed integrally to one of the rear axle chocks (9).

2. Bumper cross member (5) according to the preceding claim, in which each impact wedge (11) comprises a housing (24) intended to partially house the rear axle wedge (9) to which it is securely fixed.

3. Bumper cross member (5) according to the preceding claim, in which each impact wedge (11) takes a cylindrical shape.

4. Bumper cross member (5) according to any one of the preceding claims, in which the impact beam (10) comprises, on at least one of its faces (15, 16), stiffening ribs (29).

5. Bumper cross member (5) according to the preceding claim, in which the stiffening ribs (29) are located on a face (15) of the impact beam (10) intended to be located opposite the rear axle chocks (9).

6. Bumper crossmember (5) according to any one of claims 4 or 5, in which the stiffening ribs (29) extend longitudinally between the two impacting wedges (11).

7. Bumper cross member (5) according to any one of claims 1 to 6, in which the impact beam (10) is delimited longitudinally by two longitudinal edges (27) and extends between the two impacting wedges (11), the impact beam (10) being formed by a solid flange (30).

8. Bumper cross member (5) according to any one of claims 1 to 6, in which the impact beam (10) is delimited longitudinally by two longitudinal edges (27) and extends between the two impact wedges (11), each longitudinal edge (27) having a front flap (28), so that the impact beam (10) has a C-shaped cross section.

9. Bumper cross member (5) according to any one of claims 1 to 6, in which the impact beam (10) is delimited longitudinally by two longitudinal edges (27) and extends between the two impacting wedges (11) according to a honeycomb structure (33).

10. Motor vehicle (1) comprising: - a structural element (3) of the motor vehicle (1) comprising side rails (8) and rear axle wedges (9); - a rear bumper (4) fixed integrally to the side rails (8) - a bumper cross member (5) according to any one of the preceding claims, the bumper cross member (5) being fixed integrally to the rear axle wedges (9).

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