WO2018109342A1

WO2018109342A1 - Energy absorbing device for bumper beam of a motor vehicle

Info

Publication number: WO2018109342A1
Application number: PCT/FR2017/053489
Authority: WO
Inventors: Sergio Da Costa Pito; Hamed TRABELSI
Original assignee: Valeo Systemes Thermiques
Priority date: 2016-12-13
Filing date: 2017-12-11
Publication date: 2018-06-21
Also published as: FR3059958A1; CN211943206U; FR3059958B1

Abstract

The present invention relates to an energy absorbing device (1) for the bumper beam (2) of a motor vehicle, said energy absorbing device (1) being designed to make the connection between a bumper beam (2) and the end of a vehicle side member (3) facing the bumper beam (2), the energy absorbing device (1) comprising at least a first zone (21) made of a non-reinforced polymer material and at least a second zone (22, 23, 24) made of a reinforced polymer material comprising fibres.

Description

Energy absorber device for a motor vehicle bumper beam

The present invention relates to a power absorber device capable of providing protection in the event of a particularly frontal impact on a motor vehicle. More particularly, the invention relates to an energy absorber device for a motor vehicle bumper beam disposed between the bumper beam and the end of a vehicle spar opposite the bumper beam.

In order to absorb the energy of a particularly frontal impact at the level of a bumper beam of a motor vehicle, it is known to use energy absorbing devices that deform due to the forces exerted by the vehicle. shock. These energy absorber devices are generally made of metal material because of their strength. However, these metal energy absorber devices are heavy and do not go in the direction of the evolution of motor vehicles that seek to reduce more and more their weight.

In order to reduce the weight of the energy-absorbing devices, it is known to produce them in plastic material or in composite material, in particular combining plastic and metal. As regards the energy absorber devices made of plastic material, the latter do not give full satisfaction of the fact that they have a low specific absorbed energy, that is to say that the energy they can absorb compared to their mass is small. These plastic energy absorber devices are therefore less resistant. With respect to energy absorber devices made of composite material combining plastic and metal, the latter have a better specific absorbed energy than the plastic energy absorber devices, but they remain heavy. One of the aims of the present invention is to at least partially overcome the drawbacks of the prior art and to propose a light energy absorber device having a better specific absorbed energy. The present invention therefore relates to an energy absorber device for a bumper beam of a motor vehicle, said energy absorber device being intended to make the connection between a bumper beam and the end of a vehicle spar next to of the bumper beam, the energy absorber device comprising at least a first zone made of a non-reinforced polymer material and at least a second zone made of a reinforced polymer material comprising fibers.

The presence of a first zone made of an unreinforced polymer material and at least a second zone made of fiber-reinforced polymer material, retains a good lightness while being able to absorb more energy from possible shocks and all having better resistance to low energy shocks.

According to one aspect of the invention, the reinforced polymer material comprises glass fibers or carbon fibers. According to another aspect of the invention, the reinforced polymeric material comprises continuous fibers or staple fibers.

According to another aspect of the invention, the non-reinforced polymer material of the first portion is selected from polypropylene and polyamide.

According to another aspect of the invention, the reinforced polymer material of the second portion comprises polypropylene or polyamide.

According to another aspect of the invention, the energy absorbing device comprises: a base for attachment to a vehicle spar; ⁰ a hollow outer shell, and

⁰ of the internal walls and arranged in the hollow outer envelope,

the outer casing and the inner walls extending from the attachment base to the opposite end of the energy absorbing device in connection with the bumper beam.

According to another aspect of the invention, the fixing base and the outer hollow shell are made of non-reinforced polymer material and the inner walls are made of reinforced polymer material.

According to another aspect of the invention, the hollow outer envelope is made of unreinforced polymer material and the fixing base and the inner walls are made of reinforced polymer material. According to another aspect of the invention, the outer shell and the inner walls comprise an upper peripheral portion and a lower peripheral portion made of non-reinforced polymer material and a central portion made of reinforced polymer material. According to another aspect of the invention, the fixing base is made of non-reinforced polymer material or reinforced polymer material.

According to another aspect of the invention, the energy absorber device comprises:

⁰ an intermediate base which extends:

A first outer envelope is hollowed towards the bumper beam so as to form a first cavity,

^■ a second hollow outer casing toward the vehicle rail so as to form a second cavity, and ⁰ internal walls disposed in both the first cavity and the second cavity.

According to another aspect of the invention, the intermediate base, the first outer shell and the second outer shell are made of non-reinforced polymer material, and the inner walls of the first cavity and the second cavity are made of reinforced polymer material .

According to another aspect of the invention, the intermediate base, the first outer casing and the inner walls e the first cavity are made of unreinforced polymer material, and the second outer casing and the intersecting inner walls of the second cavity are made made of reinforced polymer material.

According to another aspect of the invention, the energy absorbing device comprises: a base for attachment to a vehicle spar and rows of honeycomb structures extending from the attachment base to the opposite end of the device energy absorber in connection with the bumper beam, the fixing base and the honeycomb structures being made of non-reinforced polymer material, and

A sinuous wall at least partially surrounding the honeycombed structure rows and extending from the fixing base to the opposite end of the energy absorber device in connection with the bumper beam, the sinuous wall being made of reinforced polymer material. Other features and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended drawings among which:

FIG. 1 shows a schematic representation of a bumper beam and an energy absorber device, FIG. 2a shows a longitudinal section along the sectional axis AA of the energy absorber device of FIG. 1 according to a first embodiment,

FIG. 2b shows a cross-section along the sectional axis BB of the energy-absorbing device of FIG. 1 according to a first variant of the first embodiment,

FIG. 2c shows a cross-section along the sectional axis BB of the energy-absorbing device of FIG. 1 according to a second variant of the first embodiment,

FIG. 3a shows a longitudinal section along the sectional axis AA of the energy-absorbing device of FIG. 1 according to a second embodiment,

FIG. 3b shows a cross section along the sectional axis BB of the energy absorber device of FIG. 1 according to a first variant of the second embodiment,

FIG. 3c shows a cross-section along the sectional axis BB of the energy-absorbing device of FIG. 1 according to a second variant of the second embodiment,

FIG. 4a shows a longitudinal section along the sectional axis AA of the energy absorber device of FIG. 1 according to a third embodiment,

FIG. 4b shows a cross-section along the sectional axis BB of the energy-absorbing device of FIG. 1 according to the third embodiment,

FIG. 5a shows a longitudinal section along the sectional axis AA of the energy-absorbing device of FIG. 1 according to a fourth embodiment, FIG. 5b shows a cross-section along the sectional axis BB of the energy-absorbing device of FIG. 1 according to the fourth embodiment,

FIG. 6a shows a longitudinal section along the sectional axis AA of the energy absorber device of FIG. 1 according to a fifth embodiment,

FIG. 6b shows a cross-section along the sectional axis BB of the energy-absorbing device of FIG. 1 according to the fifth embodiment,

FIG. 7 shows a diagram of the evolution of the resistance to deformation of the energy absorber device as a function of its contraction.

In the different figures, the identical elements bear the same reference numbers.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined and / or interchanged to provide other embodiments.

In the present description, it is possible to index certain elements or parameters, for example first element or second element as well as first parameter and second parameter or else first criterion and second criterion, etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria close but not identical. This indexing does not imply a priority of one element, parameter or criterion with respect to another, and it is easy to interchange such denominations without departing from the scope of the present description. This indexing does not imply either an order in time for example to appreciate this or that criterion.

Motor vehicles are generally provided with a bumper beam 2 disposed on the front face. As shown in Figure 1, this bumper beam 2 can be attached to a spar 3 of the vehicle. In order to absorb the shocks and to prevent the energy of the shocks being transmitted directly to the longitudinal members 3 as well as to the rest of the vehicle, the bumper beam 2 may comprise energy absorber devices 1 which make the connection between the bumper beam 2 and the ends of the longitudinal members 3 facing said bumper beam 2. These energy absorbing devices 1 deform according to a programmed deformation when the impact energy reaches a certain level in order to absorb this energy.

As shown in FIGS. 2a to 6b, the energy-absorbing device 1 comprises at least a first zone 21 made of a non-reinforced polymer material and at least a second zone 22, 23, 24 made of a reinforced polymer material comprising fibers.

By unreinforced polymer material, it is meant that the unreinforced polymer material does not comprise fibers. Thus, it is possible to have an energy absorber device 1 comprising a first zone 21 made of a material having a first shock absorption property and a second zone 22, 23, 24 made of a material having a second property. shock absorption. Of course, the energy absorbing device 1 according to the invention is such that the first zone 21 and the second zone 22, 23, 24 have different shock absorption properties, or in other words, the non-reinforced polymer material. of the first zone 21 has a property, or profile, or ability or shock absorption capacity different from the reinforced polymer material comprising fibers of the second zone 22, 23, 24. According to the invention, only the polymer material reinforced includes fibers. The non-reinforced polymer material of the first portion 21 may be selected from polypropylene and polyamide. The reinforced polymer material of the second portion 22, 23, 24 which may in turn also comprise polypropylene or polyamide.

The fibers of the reinforced polymeric material may in particular be glass fibers or carbon fibers. These fibers may be staple fibers and thus allow the manufacture of an energy absorber device 1 by injection. The fibers may be continuous fibers and allow the manufacture of an energy absorbing device 1 by thermoforming. These manufacturing methods are not limiting and it is quite possible to imagine any other known manufacturing method and adapted to the manufacture of a bi-material component and one of whose materials comprises reinforcements in the form of fibers .

In FIGS. 2a to 6b, separations are represented between the different zones 21, 22, 23 and 24. These separations are illustrative in order to mark the difference of matter between these zones 21, 22, 23 and 24. In reality, these Zones 21, 22, 23 and 24 are continuous and may have no visible demarcation due to the manufacturing process of the energy absorbing device 1, for example by bi-material injection or thermoforming.

According to a first embodiment illustrated in FIGS. 2a to 2c, and more particularly to FIG. 2a, which is a longitudinal section along the sectional axis AA of the energy-absorbing device 1 of FIG. 1, the energy-absorbing device 1 comprises:

A fixing base 51 to a vehicle spar 3 disposed at one end of the energy absorbing device 1,

⁰ an outer shell 52 hollow and

⁰ of the inner walls 53 and disposed in the outer casing 52 hollow.

The outer casing 52 and the inner walls 53 extend from the fastening base 51 to the opposite end of the energy absorbing device 1 in connection with each other. with the bumper beam 2. The fixing base 51 may in particular comprise orifices 510 in order to be fastened for example by means of bolts to the spar 3.

According to a first variant illustrated in Figure 2b which is a sectional view according to the BB mark of Figure 1, the fastening base 51 and the outer casing 52 hollow are made of non-reinforced polymer material. The inner walls 53 are made of reinforced polymer material. These internal walls 53 are here interwoven rectilinear walls which connect the inner faces of the outer casing 52. It is nevertheless possible to have different internal wall shapes 53, for example inner walls 53 which do not intersect and which are rectilinear and parallel to each other or walls having a sinusoidal section within the hollow of the outer casing 52.

According to a second variant illustrated in Figure 2c which is a sectional view according to the BB mark of Figure 1, the fastening base 51 is made of non-reinforced polymer material. The outer shell 52 and the inner walls 53 comprise for their part:

An upper peripheral portion 54a and a lower peripheral portion 54b made of non-reinforced polymer material, and

A central portion 54c disposed between the upper peripheral portion 54a and the lower peripheral portion 54b and made of reinforced polymer material.

Here is meant by upper and lower that the peripheral portions 54a and 54b are placed on either side of the central portion 54c.

In a second embodiment illustrated in FIGS. 3a to 3C, and more particularly in FIG. 3a, which is a longitudinal section along the sectional axis AA of the energy-absorbing device 1 of FIG. 1, the energy-absorbing device 1 comprises elements of the same shape as in the first embodiment with the difference that the materials in which they are made may be different.

According to a first variant illustrated in Figure 3b which is a sectional view according to the BB mark of Figure 1, the fastening base 51 and the inner walls 53 intertwined are made of reinforced polymer material. The outer shell 52 is hollow made of non-reinforced polymer material.

According to a second variant illustrated in Figure 3c which is a sectional view according to the BB mark of Figure 1, the fastening base 51 is made of reinforced polymer material. The outer shell 52 and the inner walls 53 comprise for their part:

FIGS. 4a and 4b show a third embodiment where the energy absorber device 1 comprises:

⁰ an intermediate base 55 which extends:

A first outer envelope 52a is hollowed towards the bumper beam so as to form a first cavity 7a,

^■ a second outer casing 52b towards the hollow spar vehicle so as to form a second cavity 7b, and

⁰ of the inner walls 53a, 53b intersecting disposed in both the first cavity 7a and 7b in the second cavity.

At the ends of the second outer casing 52b, the energy absorbing device 1 comprises fixing lugs 512 comprising orifices 510 in order to be fixed for example by means of bolts to the spar 3.

In this third embodiment, the intermediate base 55, the first outer shell 52a and the second outer shell 52b are made of non-reinforced polymer material. The inner walls 53a, 53b intersecting the first cavity 7a and the second cavity 7b are made of reinforced polymer material. Figures 5a and 5b show a fourth embodiment where the energy absorber device 1 comprises the same elements as in the third embodiment with the difference that the materials in which they are made may vary.

In this fourth embodiment, the intermediate base 55, the first outer casing 52a and the inner walls 53a intersecting the first cavity 7a are made of non-reinforced polymer material. The second outer envelope 52b and the inner walls 53b intersecting the second cavity 7b are made of reinforced polymer material.

According to a fifth embodiment illustrated in FIGS. 6a and 6b, the energy absorber device may comprise:

⁰ an attachment base 51 to a vehicle spar 3 and arranged structures blister 56 extending from the attachment base 51 to the opposite end of the energy absorbing device 1 in association with the bumper beam 2, the fastening base 51 and the honeycomb structures 56 being made of non-reinforced polymer material, and

⁰ a serpentine wall 58 at least partially surrounding the rows of honeycomb structure 56 and extending from the attachment base 51 to the opposite end of the energy absorbing device 1 in association with the bumper beam, the wall serpentine 58 being made of reinforced polymer material, more particularly an impregnated continuous fiber textile sheet.

The fastening base 51 may in particular comprise orifices 510 in order to be fastened for example by means of bolts to the spar 3.

FIG. 7 shows the effects and advantages of this particular composition of the energy absorbing device 1 according to the invention. FIG. 7 shows a diagram of the evolution of the contraction of an energy absorber device 1 as a function of its resistance to deformation. Curve X shows this evolution for a device energy absorber 1 made entirely of a plastic material such as polypropylene. Y curve shows this evolution for a device energy absorber 1 according to the invention.

Both curves X and Y both have a peak, respectively XI and Y 1. This peak corresponds to the initial amount of energy required for the energy absorbing device 1 to begin to deform. The peak Y1 of the energy absorber device 1 according to the invention is greater than the peak XI of the energy absorber device 1 made of plastic. This indicates that the energy absorbing device 1 according to the invention begins to deform only for shocks whose amount of energy is greater than that of the shocks that deform the plastic energy absorber device 1. This higher peak Y1 makes it possible in particular to prevent the energy-absorbing device 1 from beginning to deform during low-energy shocks, for example a shock at low speed, and thus to prevent the user from having to change the absorbers of the energy absorbers. energy 1.

In addition, the difference ΔΥ between the peak deformation resistance of the peak and the average of the deformation resistance of the curve Y is greater than the difference ΔΧ of the curve X. This indicates that the energy absorbing device 1 according to the invention can absorb a larger amount of energy than a plastic energy absorber device 1. This small difference ΔΥ makes it possible in particular to absorb a greater amount of energy during high energy shocks, for example a high-speed shock.

This is enabled by the combination of the first zone 21 made of a non-reinforced polymer material which gives the energy absorber device 1 good ductility and the second zone 22, 23, 24 made of a reinforced polymer material comprising fibers which gives the energy absorbing device 1 good strength and rigidity. In addition, the use of a reinforced polymer material and a non-reinforced polymer material makes it possible to limit the mass of the energy absorbing device 1. Thus, it can clearly be seen that the energy absorber device 1 according to the invention, because of the presence of a first zone 21 made of an unreinforced polymer material and of at least a second zone 22, 23, 24, made of fiber-reinforced polymer material, retains a good lightness while being able to absorb more energy from possible shocks and while having a better resistance to low energy shocks.

Claims

Energy absorber device (1) for a bumper beam (2) of a motor vehicle, said energy absorber device (1) being intended to connect a bumper beam (2) to the end of the bumper beam (2). a vehicle spar (3) opposite the bumper beam (2), characterized in that the energy absorbing device (1) comprises at least a first zone (21) made of a non-reinforced polymer material and at least a second zone (22, 23, 24) made of a reinforced polymer material comprising fibers.

Energy absorbing device (1) according to claim 1, characterized in that the reinforced polymer material comprises glass fibers.

Energy absorbing device (1) according to claim 1, characterized in that the reinforced polymer material comprises carbon fibers.

Energy absorbing device (1) according to one of the preceding claims, characterized in that the reinforced polymer material comprises continuous and / or discontinuous fibers.

Energy absorbing device (1) according to one of the preceding claims, characterized in that the non-reinforced polymer material of the first portion (21) is selected from polypropylene and polyamide and the reinforced polymer material of the second portion (22, 23, 24) comprises polypropylene or polyamide.

Energy absorbing device (1) according to one of the preceding claims, characterized in that it comprises:

⁰ a fixing base (51) to a spar (3) of the vehicle,

An outer shell (52) is hollow, and ⁰ internal walls (53) and disposed in the outer casing (52) hollow, the outer casing (52) and the inner walls (53) extending from the fixing base (51) to the end opposite of the energy absorbing device (1) in connection with the bumper beam (2).

7. Energy absorbing device (1) according to claim 6, characterized in that the fixing base (51) and the outer casing (52) hollow are made of non-reinforced polymer material and that the inner walls (53) ) are made of reinforced polymer material.

8. Energy absorbing device (1) according to claim 6, characterized in that the outer shell (52) hollow is made of non-reinforced polymer material and the fixing base (51) and the inner walls (53). ) are made of reinforced polymer material.

9. Energy absorbing device (1) according to claim 6 characterized in that the outer shell (52) hollow and the inner walls (53) comprise an upper peripheral portion (54a) and a lower peripheral portion (54b) realized of non-reinforced polymer material and a central portion (54c) made of reinforced polymer material.

10. Energy absorbing device (1) according to claim 9, characterized in that the fixing base (51) is made of non-reinforced polymer material. 11. Energy absorbing device (1) according to claim 9, characterized in that the fixing base (51) is made of reinforced polymer material.

12. Energy absorbing device (1) according to one of claims 1 to 5, characterized in that it comprises:

⁰ an intermediate base (55) which extends ^■ a first outer sleeve (52a) widening in the direction of the bumper beam so as to form a first cavity (7a)

^■ a second outer shell (52b) towards the hollow spar vehicle so as to form a second cavity (7b), and

0 of the inner walls (53a, 53b) disposed in both the first cavity (7a) and the second cavity (7b).

Energy absorbing device (1) according to claim 12, characterized in that:

The intermediate base (55), the first outer envelope (52a) and the second outer envelope (52b) are made of non-reinforced polymer material,

⁰ the inner walls (53a, 53b) of the first cavity (7a) and the second cavity (7b) are made of reinforced polymer material.

Energy absorbing device (1) according to claim 12, characterized in that:

⁰ the intermediate base (55), the first outer sleeve (52a) and internal walls (53a) of the first cavity (7a) are made of unreinforced polymer material,

⁰ the second outer envelope (52b) and the inner walls (53b) intersecting the second cavity (7b) are made of reinforced polymer material. 15. Energy absorbing device (1) according to one of claims 1 to 5, characterized in that it comprises:

⁰ a fixing base (51) to a vehicle longitudinal beam and rows of honeycomb structures (56) extending from the fixing base (51) to the opposite end of the energy absorber (1) liaison with the bumper beam (2), the fastening base (51) and the honeycomb structures (56) being made of non-reinforced polymer material, and

a sinuous wall (58) at least partially surrounding the honeycombed structure rows (56) and extending from the fixing base (51) to the opposite end of the energy absorbing device (1) in connection with the bumper beam (2), the sinuous wall (58) being made of reinforced polymer material.