Energy absorber for the front bumper beam of a motor vehicle

Abstract

The invention relates to an energy absorber (1) for the front bumper beam of a motor vehicle, the energy absorber (1) extending substantially along a first direction (X) and comprising first energy absorption means (3) positioned on the side of a front face (9) of the energy absorber and intended to bear against a front bumper skin of the motor vehicle during a collision and second energy absorption means positioned on the side of a rear face (10) of the energy absorber and intended to bear against the front bumper beam during a collision, the second energy absorption means having a crush resistance along a second direction (Y), perpendicular to the first direction (X), greater than that of the first energy absorption means (3).The first energy absorption means (3) comprise at least two front pads (5, 6), the second energy absorption means (4) comprise at least two rear pads (7, 8). Abstract figure: Fig. 1.

Description

Title of the invention: Energy absorber for the front bumper beam of a motor vehicle

[0001] The present invention relates to an energy absorber, in particular for a front bumper beam of a motor vehicle.

[0002] In order to perform a function of absorbing the energy of an impact against a bumper beam of a motor vehicle, it is possible to provide an energy absorber capable of deforming during the impact.

[0003] The energy absorber is assembled on the front bumper beam and follows the curve and dimension of the beam. The energy absorber comprises a rear face positioned in abutment against the front bumper beam and a front face positioned in abutment against a bumper skin.

[0004] The energy absorber is often formed from a solid rectangular single-piece. The energy absorber is often based on a compressible material, such as a polymer comprising compressed beads such as polystyrene, for example.

[0005] There are several categories of shocks that can be absorbed by such an absorber, in particular shocks at moderate speed, less than 10 km / h, and shocks at low speed, of the “parking shock” type simulating a collision in a parking lot or other, at a speed generally equal to 4 km / h.

[0006] The impact at moderate speed may be an impact known as a "pedestrian impact" corresponding to an impact against a pedestrian. The energy of this impact is absorbed in order to protect the pedestrian. The stiffness of a pedestrian impact absorber must be sufficiently low to limit the damage inflicted by this absorber on the pedestrian during the impact.

[0007] Furthermore, parking impact is for example defined by the ECE 42 standard, as an impact with a buffer defined in this ECE 42 standard, at a speed of less than 8 km / h, generally equal to 4 km / h when the buffer is presented in front of the absorber.

[0008] It is difficult to provide an energy absorber capable of effectively handling both low speed impacts and moderate speed impacts.

[0009] There is document EP2441626B1 which describes an energy absorber capable of handling both pedestrian type impacts and parking type impacts. The absorber comprises a rear wall, a front wall and an intermediate wall, positioned between the front and rear walls. First energy absorbing means are arranged between the front wall and the intermediate wall, and second energy absorbing means are arranged between the intermediate wall and the rear wall. The second energy absorbing means have a crushing resistance greater than that of the first means of energy absorption. Ribs and tongues are provided between the walls to absorb the various shocks.

[0010] However, this type of solution is not optimal for meeting the two different energy absorption requirements mentioned above at the same time.

[0011] Furthermore, this solution is not suitable for commonly used energy absorbers formed from a single piece of compressible polymer material of the polystyrene type.

[0012] The aim of the invention is therefore to overcome the drawbacks of the prior art by proposing an energy absorber capable of effectively absorbing energy from both low-speed impacts and moderate-speed impacts.

[0013] To this end, the invention thus relates, in its broadest sense, to an energy absorber for a front bumper beam of a motor vehicle. The energy absorber extends substantially in a first direction and comprises first energy absorption means positioned on the side of a front face of the energy absorber and intended to bear against a front bumper skin of the motor vehicle during an impact. The energy absorber comprises second energy absorption means positioned on the side of a rear face of the energy absorber and intended to bear against the front bumper beam during an impact. The second energy absorption means have a crushing resistance in a second direction, perpendicular to the first direction, greater than that of the first energy absorption means.

[0014] According to the invention, the first energy absorption means comprise at least two front pads and the second energy absorption means comprise at least two rear pads.

[0015] The invention thus provides an energy absorber capable of effectively absorbing energy from both low speed impacts and moderate speed impacts.

[0016] The proposed energy absorber makes it possible to meet the requirements of two different standards at the same time thanks to the two energy absorption means which are of different design.

[0017] Costs are reduced because the two absorption means are integrated into a single single piece, obtained during a single manufacturing operation, by molding for example.

[0018] The invention also makes it possible to use energy absorbers made of compressible polymer material of the polystyrene type which are also capable of absorbing energy effectively from both low speed impacts and moderate speed impacts according to two different standards.

[0019] According to a variant, the front pads have dimensions smaller than the dimensions of the rear pads.

[0020] This allows shock absorption at different speed ranges.

[0021] According to a variant, the front studs are positioned at the location of a central zone of the energy absorber.

[0022] This position allows the absorption of shocks at low speeds in the most efficient way possible.

[0023] According to a variant, the two front pads are positioned opposite each other. The two rear pads are positioned on either side of the two front pads in the first direction.

[0024] This position allows shock absorption at moderate speeds in the most efficient way possible.

[0025] According to a variant, the energy absorber comprises a hollow housing delimited in part by the two front studs, by the two rear studs, by two lateral portions positioned on either side of the rear studs and by two longitudinal walls connected to the lateral portions.

[0026] The hollow housing is hollowed out of non-useful areas, which makes it possible to reduce the mass of the energy absorber and to achieve an economic gain because there is material only in the functional areas.

[0027] According to a variant, each front stud is connected to a first longitudinal wall and to a second longitudinal wall by extending in a third direction, perpendicular to the first and second directions. Each front stud projects relative to the longitudinal walls in the second direction.

[0028] Thanks to this projection of the front studs forming a protuberance, the front studs are the first elements of the central zone of the energy absorber which come to bear against the bumper skin, during an impact. The front studs can also already be in contact with the bumper skin before the impact.

[0029] According to a variant, the hollow housing comprises a first opening formed between the two front studs, a second opening formed between the two rear studs, a third opening formed between a first lateral portion and a first front stud, a fourth opening formed between a second lateral portion and a second front stud, a fifth opening formed between the first lateral portion and a first rear stud and a sixth opening formed between the second lateral portion and a second rear stud.

[0030] This makes it possible to eliminate non-useful areas, which makes it possible to reduce the mass of the energy absorber and achieve an economic gain.

[0031] According to a variant, each front stud comprises a central part connected to the longitudinal walls by two first opposite legs.

[0032] This configuration allows for optimal shock absorption at low speed.

[0033] According to a variant, each rear stud has an H shape with a portion central and two second legs, each connected to the two longitudinal walls by two end portions. The two second legs are separated by the central portion. Each rear stud projects from the longitudinal walls in the second direction.

[0034] This configuration allows for optimal shock absorption at moderate speed.

[0035] The invention also relates to a motor vehicle comprising a front bumper beam on which an energy absorber as defined above is mounted.

[0036] Embodiments of the present invention will be described below, by way of non-limiting examples, with reference to the appended figures in which:

[0037] [Fig-1] schematically illustrates a front view of an energy absorber according to the invention;

[0038] [Fig.2] schematically illustrates a view from the rear of the energy absorber;

[0039] [Fig.3] schematically illustrates a view along an XY section of the absorber energy mounted between the bumper beam and a bumper skin;

[0040] [Fig.4] schematically illustrates a detailed view along an XY section of a front stud positioned between the bumper beam and the bumper skin;

[0041] [Fig.5] schematically illustrates a detailed view along an XY section of a rear stud positioned between the bumper beam and the bumper skin.

[0042] The terms “front” and “rear” shall be understood in relation to the general orientation of the vehicle as taken in its normal direction of travel.

[0043] In the remainder of the description, elements having an identical structure and / or similar functions will be designated by the same reference.

[0044] Figures 1 to 5 illustrate an energy absorber 1 for a front bumper beam 2 of a motor vehicle.

[0045] The energy absorber 1 is assembled on the front bumper beam 2 and follows the curve and dimension of the front bumper beam 2 which is slightly curved.

[0046] The energy absorber 1 comprises a rear face 10 positioned in abutment against the front bumper beam 2 and a front face 9 positioned in abutment against a front bumper skin 11. In other words, the energy absorber 1 is positioned between the front bumper beam 2 and the front bumper skin 11.

[0047] The energy absorber 1 is a single-piece part of generally solid rectangular shape which is slightly curved. The energy absorber 1 is based on a compressible material, such as a polymer comprising compressed beads such as polystyrene, for example. The energy absorber 1 can be obtained during a molding operation, for example.

[0048] The energy absorber 1 extends along the front bumper beam 2 substantially along a first direction X and comprises first means energy absorption 3 positioned on the side of the front face 9 of the energy absorber 1 and intended to come into contact with the front bumper skin 11 during an impact.

[0049] The energy absorber 1 also comprises second energy absorption means 4 positioned on the side of the rear face 10 of the energy absorber 1 and intended to come into contact with the front bumper skin 11 during an impact.

[0050] The second energy absorption means 4 have a resistance to crushing in a second direction Y, perpendicular to the first direction X, greater than that of the first energy absorption means 3. The second direction Y corresponds to the direction of travel of the vehicle.

[0051] Indeed, the first energy absorption means 3 are designed to absorb a low-speed shock, of the “parking shock” type simulating a collision in a parking lot or other.

[0052] Parking impact is for example defined by the ECE 42 standard, as an impact with a buffer defined in this ECE 42 standard, at a speed of less than 8 km / h, generally equal to 4 km / h when the buffer is presented facing the energy absorber 1.

[0053] As for the second energy absorption means 4, they are designed to absorb an impact at moderate speed, such as an impact known as a “pedestrian impact”, for example, corresponding to an impact against a pedestrian. The energy of this impact is absorbed in order to protect the pedestrian.

[0054] According to the invention, the first energy absorption means 3 comprise at least two front pads 5, 6 and the second energy absorption means 4 comprise at least two rear pads 7, 8.

[0055] The rear pads 7, 8 and the front pads 5, 6 are formed from the same material as the rest of the energy absorber 1 and are compressible so as to absorb the energy during a frontal impact of the vehicle.

[0056] In the example of Figures 1 to 5, the first energy absorption means 3 comprise two front pads 5, 6 and the second energy absorption means 4 comprise two rear pads 7, 8.

[0057] Alternatively, the first energy absorption means 3 may comprise more than two front pads 5, 6 and the second energy absorption means 4 may comprise more than two rear pads 7, 8.

[0058] The front pads 5, 6 have smaller dimensions than the rear pads 7, 8 because they must absorb less energy than the rear pads 7, 8, the front and rear pads 5, 6, 7, 8 being made of the same material. In other words, the front pads 5, 6 have a smaller volume than that of the rear pads 7, 8.

[0059] For example, at least the width of the front pads 5, 6 along the first direction X is less than the width of the rear pads 7, 8.

[0060] The front pads 5, 6 also have a different shape from the rear pads 7, 8.

[0061] The front pads 5, 6 are positioned at the location of a central zone 13 of the energy absorber 1, on the side of the front face 9 of the energy absorber 1. In other words, the front pads 5, 6 are each positioned opposite a plane of symmetry parallel to the plane Y, Z and crossing the middle of the energy absorber 1. The two front pads 5, 6 are distant from each other and positioned symmetrically on either side of the plane of symmetry.

[0062] The two rear pads 7, 8 are positioned on the side of the rear face 10 of the energy absorber 1, on either side of the two front pads 5, 6. The two rear pads 7, 8 are distant from each other and positioned symmetrically with respect to the plane of symmetry.

[0063] The two front pads 5, 6 are separated by a distance dl, less than a distance d2 separating the two rear pads 7, 8. The distance d2 is at least equal to twice the distance dl.

[0064] The energy absorber 1 comprises two identical lateral portions 17, 18 positioned symmetrically on either side of the front pads 5, 6 and the rear pads 7, 8. Each lateral portion 17, 18 comprises absorber elements 27 extending relative to a lateral wall 28, 29 in the second direction Y.

[0065] The energy absorber 1 comprises a hollow housing 16 delimited in part by the two front studs 5, 6, the two rear studs 7, 8, the two lateral portions 17, 18 and by two longitudinal walls 19, 20 connected to the lateral portions 17, 18.

[0066] The two longitudinal walls 19, 20 are parallel to each other. The two front studs 5, 6 and the two rear studs 7, 8 are partly positioned between the two longitudinal walls 19, 20.

[0067] The hollow housing 16 comprises a first opening 14 formed between the two front studs 5, 6.

[0068] The hollow housing 16 comprises a second opening 15 formed between the two rear studs 7, 8. The two front studs 5, 6 are positioned facing the second opening 15.

[0069] A third opening 30 is formed between a first lateral portion 17 and a first front stud 5. A fourth opening 31 is formed between a second lateral portion 18 and a second front stud 6.

[0070] Each front stud 5, 6 is connected to a first longitudinal wall 19 and to a second longitudinal wall 20 extending in a third direction Z, perpendicular to the first and second directions X, Y.

[0071] Each front stud 5, 6 extends in the second direction Y, projecting relative to the longitudinal walls 19, 20 and more precisely relative to two opposite front edges 32, 33 of the longitudinal walls 19, 20, towards the front bumper skin 11, so that the front studs 5, 6 bear against the bumper skin. front impacts 11, at least in the case of a frontal impact. In other words, the two front studs 5, 6 protrude from the front face 9 of the energy absorber 1.

[0072] Thanks to this projection of the front studs 5, 6 forming a protuberance, the front studs 5, 6 are the first elements of the central zone of the energy absorber 1 which come to bear against the bumper skin 11 during an impact. The front studs 5, 6 can also already be bearing against the bumper skin 11 before the impact.

[0073] Each front stud 5, 6 comprises a central part 21 connected to the front edges 32, 33 of the longitudinal walls 19, 20 by two first opposite legs 22. The central part 21 has a generally elliptical shape. The first two legs 22 have a generally parallelepiped shape.

[0074] Alternatively and as illustrated in [Fig.4], the front bumper skin 11 comprises holding means 41 for maintaining the position of the front studs 5, 6 during an impact. The holding means 41 are arranged on either side of each front stud 5, 6 and project from a front wall 42 of the front bumper skin 11 in the direction of the energy absorber 1.

[0075] As illustrated in [Fig.2], each rear stud 7, 8 has an H shape with a central portion 23 positioned between two second legs 24, each connected to each longitudinal wall 19, 20 by two end portions 43.

[0076] The second legs 24 each extend from a first rear edge 35 of the first longitudinal wall 19 to a second rear edge 36 of the second longitudinal wall 20.

[0077] Two cavities 25 are formed on either side of the central portion 23. Each cavity 25 is delimited by a face 39 of the central portion 23, two end portions 43 of the second legs 24 and by a portion of an internal wall 34 of one of the longitudinal walls 19, 20. The central portion 23 has a rectangular section. The second legs 24 have a trapezoidal and elongated shape.

[0078] Each rear stud 7, 8 projects relative to the longitudinal walls 19, 20 and more precisely relative to two opposite rear edges 35, 36 of the longitudinal walls 19, 20, in the second direction Y and towards the front bumper beam 2, so that the rear studs 7, 8 bear against the front bumper beam 2, at least during a frontal impact. Each rear stud 7, 8 forms a protuberance and protrudes from the rear face 10.

Claims

Claims

1. Energy absorber (1) for a front bumper beam (2) of a motor vehicle, the energy absorber (1) extending substantially in a first direction (X) and comprising first energy absorption means (3) positioned on the side of a front face (9) of the energy absorber (1) and intended to bear against a front bumper skin (11) of the motor vehicle during an impact and second energy absorption means (4) positioned on the side of a rear face (10) of the energy absorber (1) and intended to bear against the front bumper beam (2) during an impact, the second energy absorption means (4) having a crushing resistance in a second direction (Y), perpendicular to the first direction (X), greater than that of the first energy absorption means (3), characterized in that the first energy absorption means energy (3) comprise at least two front pads (5, 6),the second energy absorption means (4) comprising at least two rear pads (7, 8).,

2. Energy absorber (1) according to claim 1, characterized in that the front pads (5, 6) have dimensions smaller than the dimensions of the rear pads (7, 8).

3. Energy absorber (1) according to any one of claims 1 or 2, characterized in that the front studs (5, 6) are positioned at the location of a central zone (13) of the energy absorber (1).

4. Energy absorber (1) according to any one of claims 1 to 3, characterized in that the two front pads (5, 6) are positioned opposite each other, the two rear pads (7, 8) being positioned on either side of the two front pads (5, 6) in the first direction (X).

5. Energy absorber (1) according to any one of claims 1 to 4, characterized in that it comprises a hollow housing (16) delimited in part by the two front studs (5, 6), the two rear studs (7, 8), by two lateral portions (17, 18) positioned on either side of the rear studs (7, 8) and by two longitudinal walls (19, 20) connected to the lateral portions (17, 18).

6. Energy absorber (1) according to claim 5, characterized in that each front stud (5, 6) is connected to a first longitudinal wall (19) and to a second longitudinal wall (20) by extending along a third direction (Z), perpendicular to the first and second directions (X, Y), each front stud (5, 6) projecting relative to the longitudinal walls (19, 20) in the second direction (Y).

7. Energy absorber (1) according to any one of claims 5 or 6, characterized in that the hollow housing (16) comprises a first opening (14) formed between the two front studs (5, 6), a second opening (15) formed between the two rear studs (7, 8), a third opening (30) formed between a first lateral portion (17) and a first front stud (5), a fourth opening (31) formed between a second lateral portion (18) and a second front stud (6), a fifth opening (37) formed between the first lateral portion (17) and a first rear stud (7) and a sixth opening (38) formed between the second lateral portion (18) and a second rear stud (8).

8. Energy absorber (1) according to any one of claims 5 to 7, characterized in that each front stud (5, 6) comprises a central part (21) connected to the longitudinal walls (19, 20) by two first opposite legs (22).

9. Energy absorber (1) according to any one of claims 5 to 8, characterized in that each rear stud (7, 8) has an H shape with a central portion (23) and two second legs (24), each connected to the two longitudinal walls (19, 20) by two end portions (43), the two second legs (24) being separated by the central portion (23), each rear stud (7, 8) projecting relative to the longitudinal walls (19, 20) in the second direction (Y).

10. Motor vehicle characterized in that it comprises a front bumper beam (2) on which is mounted an energy absorber (1) as defined according to any one of claims 1 to 9.

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