MOTOR VEHICLE WITH PEDESTRIAN-OPTIMIZED SHOCK ABSORBER

Abstract

MOTOR VEHICLE WITH PEDESTRIAN-OPTIMIZED SHOCK ABSORBER The invention relates to a shock absorber (2) for a motor vehicle (8), intended to be arranged transversely between a bumper panel (11) and a lower cross member (6) of the motor vehicle, comprising: - deformable chambers (4); - a bearing surface (4.1) intended to bear against the lower cross member; and - a front face (10) intended to be covered by the bumper panel; notable in that, in its normal mounting position on the motor vehicle, the front face has a longitudinal profile inclined forwards and upwards, and is located at an average height (A) lower than an average height (B) of the bearing surface. (Figure to be published with the abbreviation: Figure 3)

Description

Title of the invention: MOTOR VEHICLE WITH PEDESTRIAN-OPTIMIZED SHOCK ABSORBER technical field

[0001] The present invention relates to the field of motor vehicles, more particularly to the field of motor vehicle bumpers. Previous technique

[0002] Among the various test protocols to which motor vehicles are subjected, there are tests with pedestrians to determine the most dangerous points for pedestrians' legs during a frontal collision with the motor vehicle, particularly at a speed of 40 km / h.

[0003] Indeed, the bumper is the part most often that comes into contact first with the pedestrian in the event of an impact, and mainly with the latter's legs, so the less damage the vehicle causes to the pedestrian's legs, the better the response of said vehicle to the test, this is why the responses of a motor vehicle to tests with pedestrians are criteria increasingly taken into consideration by current motor manufacturers.

[0004] In this regard, motor vehicles include, at the level of their front face, an absorber placed in support on a transverse beam, and which is conventionally separated from the bumper skin, thus allowing the absorption of the kinetic energy of a light impact in order to improve the response of vehicles to pedestrian tests.

[0005] The published patent document EP 1 799 515 B1 discloses a reinforcement of a lower impact area of ​​a front bumper of a motor vehicle providing protection for the legs of pedestrians in the event of a collision, said reinforcement comprising a base plate disposed against a cross member and provided with a multitude of longitudinal ribs.

[0006] However, the solution in this document has room for improvement, as the lower impact zone of the bumper is not suitable for all the different platform heights of motor vehicles. Indeed, the damage caused to pedestrians' legs is likely to be significant, particularly in the case of a high motor vehicle platform, such as those found on SUVs. Description of the invention

[0007] The present invention aims to overcome at least one of the drawbacks of the aforementioned prior art. More specifically, the invention aims to to propose a simple, efficient and economical solution to ensure effective protection of pedestrians' legs against the lower part of the bumper in the event of a collision.

[0008] For this purpose, the invention relates to a shock absorber for a motor vehicle, intended to be arranged transversely between a bumper wall and a lower transverse beam of the motor vehicle, comprising: - deformable boxes; - a bearing face intended to bear on the lower transverse beam; and - a front face intended to be covered by the bumper wall; remarkable in that in normal mounting position on the motor vehicle, the front face has a longitudinal profile inclined forwards and upwards, and is located at an average height lower than an average height of the bearing face.

[0009] Advantageously, the front face is formed of a series of transverse walls extending along a common transverse surface corresponding to said front face.

[0010] According to one embodiment, the longitudinal profile of the front face is curved and convex.

[0011] Advantageously, the convexity of the front face is to be considered from a point of view external to the absorber, for example, from the bumper wall which is opposite the front face.

[0012] According to one embodiment, the inclination of the longitudinal profile of the front face, with respect to a vertical direction, gradually decreases from a lower edge to an upper edge of said longitudinal profile of the front face.

[0013] According to one embodiment, the inclination of the longitudinal profile of the front face, with respect to a vertical direction, is between 20° and 70°.

[0014] According to one embodiment, the deformable boxes comprise vertical longitudinal walls forming forward and downward inclined extensions, supporting the front face.

[0015] According to one embodiment, the extensions of the vertical longitudinal walls are connected to each other by transverse walls inclined downwards and forwards.

[0016] According to one embodiment, the transverse walls inclined downwards and forwards are adjacent to a lower edge of the front face.

[0017] According to one embodiment, the support face is formed by rear transverse walls of the deformable boxes.

[0018] According to one embodiment, said shock absorber having a transverse profile, at the level of the deformable boxes, in crenellations.

[0019] The invention also relates to a motor vehicle comprising, at the front: - a lower transverse bumper beam; - a bumper panel; - a shock absorber disposed between the lower crossbeam and the bumper wall; the absorber being configured to provide protection for pedestrians' legs against a lower part of the bumper in the event of a collision, remarkable in that the shock absorber is according to the invention

[0020] Preferably, the front face is longitudinally distant from the support face by a distance corresponding to at most 200 mm.

[0021] The measures of the invention are advantageous in that the shock absorber of the motor vehicle deforms in compression in order to absorb energy, during a low-speed frontal impact, in an elastic manner without causing rupture of said absorber, while protecting the legs of the pedestrian, so as to effectively comply with the various biomechanical criteria required by regulations and the various test protocols with pedestrians.

[0022] Indeed, the absorber comprising extensions positioned below the crossbeam of the motor vehicle, is able to deform without spilling, ensuring a large absorption surface with the lower part of the pedestrian's leg.

[0023] The absorber also reduces the front overhang of the motor vehicle, resulting in a reduction of its overall mass. Furthermore, vehicle installation is quick and easy, thus reducing costs. Brief description of the drawings

[0024] [Fig. 1] represents a perspective view of a shock absorber for a motor vehicle, according to the invention;

[0025] [Fig.2] represents an enlarged perspective view of the absorber of [Fig.1], said absorber being arranged at the front of a lower transverse beam of the motor vehicle;

[0026] [Fig.3] represents a longitudinal cross-sectional view of a motor vehicle comprising the absorber of the [Fig.1] in normal mounting position, said motor vehicle being according to the invention;

[0027] [Fig.4] represents a longitudinal cross-sectional view schematically illustrating the deformation of the absorber of [Fig.3] due to a frontal impact during a test protocol with pedestrians. Detailed description

[0028] The use of the term "approximately" in this description corresponds to a margin of ±10% relative to the nominal value.

[0029] Fig. 1 represents a perspective view of a shock absorber 2 for a motor vehicle, according to the invention.

[0030] The absorber 2 is intended to be disposed between a bumper wall and a lower crossbeam of the motor vehicle, illustrated in [Fig.3].

[0031] It can be seen in [Fig. 1] that the absorber 2 comprises several deformable chambers 4 extending transversely (along the Y-axis) from said absorber. These chambers 4 allow for a progressive longitudinal deformation (along the X-axis) of the absorber 2, so as to protect pedestrians' legs from the lower part of the bumper of the motor vehicle in the event of a collision. Such deformation will be further explained in this description.

[0032] Fig. 2 represents an enlarged perspective view of the absorber 2, in which the shape of the deformable boxes 4 can be better observed.

[0033] Each deformable box 4 preferably comprises a parallelepiped shape with a rear transverse wall 4.1 forming a bearing face intended to bear on the lower transverse beam 6 of the motor vehicle 8, and an open area 4.2 at the front of the deformable box 4.

[0034] The absorber 2 comprises vertical longitudinal walls 5 forming extensions 5.1 inclined forwards and downwards, these extensions will be further described in [Fig.3].

[0035] The absorber 2 further comprises a front face 10 intended to be covered by the bumper wall of the vehicle 8, said front face 10 being formed by transverse walls 10 extending transversely between the vertical longitudinal walls 5 at the front of the deformable boxes 4.

[0036] The various walls forming the deformable boxes 4, as well as the transverse wall 10 of the front face, have a thickness of between 2 and 5 mm, and are more preferably equal to 3 mm. Preferably, the boxes 4 have a transverse width of between 40 mm and 80 mm; more preferably, each box has a width of approximately 65 mm between two vertical longitudinal walls 5. The transverse walls 10 forming the front face extend transversely with a width of between 30 mm and 70 mm, and are more preferably equal to approximately 57 mm.

[0037] Preferably, the absorber 2 has a cross-sectional profile with crenellations at the level of the deformable boxes 4. Advantageously, the cross-sectional profile with crenellations as well as the parallelepiped shape of the deformable boxes 4 comprising open areas 4.2, makes it possible to distribute the kinetic energy during an impact in a homogeneous manner in order to transfer it to the cross beam 6.

[0038] Advantageously, each deformable box 4 comprises a longitudinal profile inclined forwards and upwards. Indeed, such an inclination is visible on the transverse wall 10 of [Fig. 2], which has a curved and convex shape when viewed from the outside. In this configuration, the deformable boxes 4 ensure improved compressibility and a progressive increase in the contact area with pedestrians' legs.

[0039] Figure 3 represents a longitudinal cross-sectional view of the motor vehicle including absorber 2 in normal mounting position.

[0040] It can be seen that the bearing face 4.1 of the absorber 2 is longitudinally offset from the lower transverse beam 6, this offset is between 5 mm and 30 mm and allows a margin of retreat for the absorber 2 in the event of a frontal impact, said offset being more preferably equal to 15 mm.

[0041] The longitudinal profile inclined forward and upward of the front face 10 is located at an average height A less than an average height B of the bearing face 4.1, the latter being opposite an external face 6.1 of the transverse beam 6, thus the average height B corresponds to an extension of the average height of the transverse beam 6.

[0042] The average heights A and B can be considered as the positioning of a neutral axis of each of the absorber 2 and the crossbeam 6, respectively. For this purpose, in the event of a collision with a pedestrian's leg, the impact on the absorber will be longitudinally centered along the neutral axis A, avoiding any risk of the absorber 2 tipping over. Thus, the motor vehicle 8 can be considered an SUV-type vehicle, which has a high platform and larger wheels compared to a sedan-type vehicle. Advantageously, the absorber 2 improves the response of SUV-type vehicles to pedestrian impact test protocols.

[0043] Preferably, the vertical offset between the average height A and B is between 10 mm and 60 mm, and more preferably between 20 mm and 40 mm.

[0044] The longitudinal profile of the front face 10 can be better observed when positioned opposite the bumper wall 11. Indeed, said profile has an inclination, with respect to the vertical direction Z, which decreases progressively from a lower edge 4.3 to an upper edge 4.4 of said longitudinal profile of the front face 10. In this respect, the inclination of the longitudinal profile of the front face 10 is progressive and goes from 20° to 70° with respect to the vertical direction Z.

[0045] The extensions 5.1 of the vertical longitudinal walls 5 are connected to each other by transverse walls inclined downwards and forwards 10.1, these inclined transverse walls 10.1 are adjacent to the lower edge 4.3, and are preferably monobloc with said lower edge 4.3 so as to form a continuity of material from the upper edge 4.4 to the bearing face 4.1.

[0046] The deformable boxes 4 comprise a lower wall 10.2 connecting the support face 4.1 to the transverse wall inclined downwards and forwards 10.1. In this configuration, the inclined transverse walls 10.1 of the absorber 2 have an angle α between 120° and 160° with the lower wall 10.2. More preferably, the angle α is approximately 140°.

[0047] Preferably, each of the vertical longitudinal walls 5 has an upper step 7 comprising a first downward quarter-circle rounded edge 7.1 with a radius of approximately 8 mm, and a second forward quarter-circle rounded edge 7.2 with a radius of approximately 20 mm. The upper step 7 allows the forward and downward position of the extensions 5.1 to be tracked.

[0048] Fig. 4 represents a longitudinal cross-sectional view schematically illustrating the deformation of the absorber 2 due to a frontal impact 1 during a pedestrian test protocol.

[0049] The absorber 2' shown in dotted lines corresponds to the absorber 2 after it has completely absorbed the kinetic energy of the frontal impact 1. It can be observed that the deformable box 4' of the absorber 2' extends vertically upwards from the very first moments of the impact 1, advantageously increasing the impact surface with the pedestrian's leg and thus better deflecting the lower part of said leg. As a result, the motor vehicle is able to transmit greater forces without risk of tibia fracture.

[0050] Furthermore, the deformable boxes 4 are able to deform after the impact 1 thanks to their advantageous geometry, so as to minimize the deformation of the rear transverse walls 4.1, and to ensure good support of the bearing face 4.1 against the external face 6.1 of the transverse beam 6. Vertical downward buckling of the absorber 2' is avoided, and its stability along the vertical direction is guaranteed.

[0051] The motor vehicle 8 of the invention makes it possible to effectively comply with the various biomechanical criteria required by the “ECE127” regulation for a “FLEXPLI” type leg impact, and also complies with the criteria required for “xNCAP” type “APli” consumer leg impacts, i.e. leg comprising an additional mass of 11 kg in the upper part.

Claims

Demands

1. Shock absorber (2) for a motor vehicle (8), intended to be arranged transversely between a bumper wall (11) and a lower crossbeam (6) of the motor vehicle (8), comprising: - deformable boxes (4); - a bearing face (4.1) intended to bear on the lower crossbeam (6); - and a front face (10) intended to be covered by the bumper wall (11); wherein in the normal mounting position on the motor vehicle (8), the front face (10) has a longitudinal profile inclined forwards and upwards, and located at an average height (A) lower than an average height (B) of the bearing face (4.1), characterized in that the deformable boxes (4) comprise vertical longitudinal walls (5) forming extensions (5.1) inclined forwards and downwards, supporting the front face (10), and in that the extensions (5.1) are connected to each other by transverse walls inclined (10.1) downwards and forwards.

2. Shock absorber (2), according to claim 1, wherein the longitudinal profile of the front face (10) is curved and convex.

3. Shock absorber (2), according to claim 2, wherein the inclination of the longitudinal profile of the front face (10), with respect to a vertical direction (Z), gradually decreases from a lower edge (4.3) to an upper edge (4.4) of said longitudinal profile of the front face (10).

4. Shock absorber (2), according to any one of claims 1 to 3, wherein the inclination of the longitudinal profile of the front face (10), with respect to a vertical direction (Z), is between 20° and 70°.

5. Shock absorber (2), according to any one of claims 1 to 4, wherein the downwardly and forward-inclined transverse walls (10.1) are adjacent to a lower edge (4.3) of the front face (10).

6. Shock absorber (2), according to any one of claims 1 to 5, wherein the bearing face (4.1) is formed by rear transverse walls (4.1) of the deformable boxes (4).

7. Shock absorber (2) according to any one of claims 1 to 6, having a cross-sectional profile, at the level of the deformable boxes (4), in crenellations.

8. Motor vehicle (8) comprising, at the front: - a lower cross member (6) of bumper; - a bumper wall (11); - a shock absorber (2) disposed between the lower cross member (6) and the bumper wall (11); the absorber (2) being configured to provide protection of pedestrians' legs against a lower part of the bumper in the event of a collision, characterized in that the shock absorber (2) is according to any one of claims 1 to 7.

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