EP1831056A2

EP1831056A2 - Front panel for motor vehicle

Info

Publication number: EP1831056A2
Application number: EP05850605A
Authority: EP
Inventors: Sébastien GUINEHUT
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2004-12-30
Filing date: 2005-12-23
Publication date: 2007-09-12
Also published as: FR2880319A1; FR2880319B1; WO2006072695A3; EP2154030A2; EP2154030A3; WO2006072695A2

Abstract

The invention relates to a front panel for a motor vehicle comprising a shock-absorbing structure. According to the invention, the shock-absorbing structure consists of an upper cross member (108) comprising a support (4) bearing an absorber (6; 16; 36; 46; 56) which is formed by a group of absorbing segments (10, 12; 18, 20; 22, 26, 38; 48; 60) which are arranged in a chosen geometry such that, from a selected force threshold, the relative stiffness of the absorber (6; 16; 36; 46; 56) is essentially zero so that the absorber can deform under an essentially-constant force in the event of an impact. The invention is suitable for use in the automobile industry.

Description

Front side for a motor vehicle.

The invention relates to a front face for a motor vehicle.

A front panel module is a structural element capable of integrating a variety of vehicle equipment, such as projectors, turn signals, buzzer, heat exchanger, fan motor unit or complete cooling module, etc.

The module, thus provided with its equipment, constitutes a unitary element prepared and delivered by the equipment manufacturer, ready to be mounted on the vehicle by the manufacturer. The assembly of this unitary module is made by connecting to lateral structural elements of the vehicle, such as longitudinal members, wings or hulls, and then placing a bumper or front shield attached to the module.

The front face, because of its positioning, is the contact element that is stressed during a frontal impact. It is especially designed to absorb shocks. These shocks are generally classified into three categories used in European standards.

The first concerns "low speed shocks", centered, offset or corner, whose speed is between 2.5 and 4 km / h. The second category concerns "medium speed shocks", whose speed is around 16 km / h. Finally, the third category concerns "high-speed shocks", whose speed is between 56 and 65 km / h.

The variety of these shocks is causing government agencies to put in place increasingly stringent regulations to protect drivers and their environment in these shocks.

The front faces of a motor vehicle are thus provided with bumpers intended to absorb all or part of the frontal impacts of vehicles to protect passengers. These bumpers are used to absorb shocks with a wide variety of exterior elements, such as other vehicles, walls or poles. However, these bumpers are likely to cause serious damage in the event of a frontal impact with a pedestrian. In this case it is observed that severe damage is done to the pedestrian, and more particularly to his jaw (which includes the femur-knee-shin joint), as well as to his hip or to his head when he is a child.

The devices of the prior art do not provide optimal protection of the leg and the rest of the body of the pedestrian which allows to avoid consequent damage. These devices also do not provide protection for the rest of the pedestrian's body, such as the hip, which is likely to be damaged during a "pedestrian impact". A pedestrian impact refers to the interaction between the front of a vehicle and the jab (which includes the femur - knee - shin section) of a pedestrian that it collides with, as well as its hip or, its head when is a child. In particular, these devices are not provided for deformation under constant stress.

The aim of the invention is to improve the situation.

It proposes for this purpose a front face comprising an upper cross member forming a frame. The upper crossbar comprises a support which carries an absorber comprising a set of absorbent portions arranged in a geometry chosen so that the absorber has, from a chosen stress threshold, a relative stiffness substantially zero to be deformable under substantially constant force during an impact.

Such a front face makes it possible to protect a pedestrian during a pedestrian impact with a vehicle. The protection obtained is all the better as the use of absorbent portions arranged according to a selected geometry makes it possible to obtain a deformation of these portions under constant stress.

This means the absence of hard spots and therefore better absorption of shock energy and therefore better pedestrian protection. In a first embodiment, the absorber is a plate supporting a set of fins forming absorbent portions.

In another embodiment, the absorber is a set of absorptive portion and sidewall containing cells, each cell having at least one sidewall adjoined to a sidewall of another cell.

In another embodiment, the absorber is a set of tubes forming absorbent portions and having an axis substantially orthogonal to the support.

These various embodiments make it possible to produce impact protection devices with a chosen geometry. These different geometries make it possible to size the almost constant force under which the device deforms during an impact.

The invention also relates to a front face comprising at least one such protection device against shocks, which can be carried out in one piece.

Other advantages and characteristics of the invention will appear better on reading the description by way of nonlimiting illustration of examples from the figures in the accompanying drawings in which:

- Figure 1 shows a schematic partial side sectional view of a front portion of a vehicle incorporating a device according to the invention;

- Figure 2 shows a schematic perspective view of an absorber of a device according to the invention made in the form of lamellar architecture;

- Figures 2a and 2b respectively show a front view and a top view of Figure 2; FIG. 3 represents a variant of the device of FIG. 2

FIGS. 4 to 6 show top views of variants of the absorber of FIG. 2 produced in the form of cellular architecture;

- Figure 7 shows a top view of a variant of the absorber of Figure 2 in the form of tubular architecture;

- Figure 8 shows a perspective view of a variant of the absorber of Figure 2 realized as a bellows segment architecture;

FIG. 9 represents a perspective view of a variant of the absorber of FIG. 2 made in the form of a hollow body;

FIG. 10 is a generic graph of the force transmitted as a function of the displacement by an absorber of a device according to

The invention; and

- Figures 11a and 11b are schematic views in front and rear perspective of a front face incorporating devices according to the invention.

In the rest of the description, reference will be made to the concept of reinforcement. In the context of the invention, the term "armature" designates any structural element of a front face, whether it be a frame, a beam, a cross member or a projector.

As can be seen in FIG. 1, a front portion 1 of a motor vehicle comprises a shock protection device 2 located under a hood C, above a bumper beam P and a shield B. The device 2 comprises a support 4 and an absorber 6. A reference (X, Y, Z) is provided. A second reference (X1, Y1) offset by an angle α about the Z axis with respect to the (X, Y) plane is oriented in a direction of shock represented by. an arrow F. The absorber 6 has a depth ps' extending in the direction X1 by at least 140 mm.

In the example described here, the support 4 is a plate integrated into a frame of a front face, as will be described below. Nevertheless, this support could only be reported on this frame. The choice of a support 4 having a rigidity chosen allows to control the force transmitted during a frontal impact once the absorber 6 compressed.

The support 4 can thus be made of a conventional or hybrid plastic material. Hybrid plastic material is any material composed of at least two different or different materials, at least one of which is a plastic material. For example, a hybrid plastic material may be made of metal covered with a plastic material, or the mixture of two different plastics.

In a first embodiment, the absorber 6 is lamellar architecture.

Figure 2 shows a perspective view of this absorber. The absorber 6 comprises a central plate 10 extending substantially along the axis Z orthogonal to the mark (X1, Y1) of FIG. 1. This plate 10 also extends along the axis Y1. Along the axis Z, fins 12 are arranged transversely to the plate 10, on both sides thereof.

As can be seen in FIG. 2a, the plate 10 has a profile making it possible to match the shape of the cover C. Figure 2b shows that the fins 12 are spaced substantially evenly along the axis of the plate 10 and that they have a substantially constant thickness e.

In the example described here, the distance d between the fins 12 is 50 mm. The fins 12 are identical and each have a width h of at least 150 mm, a length p of 200 mm and a thickness of one millimeter. The fins 12 are made of plastic material chosen to obtain the desired deformation properties. It is possible to dispose a cellular material 14 between the fins 12, as shown in FIG. 2b by way of example. This cellular material is here and for the rest of the plastic foam or metal foam, and it can fill partially or completely the space between the fins 12.

Figure 3 shows a variant of Figure 2 in which the central plate 10 extends substantially in the plane (Xl, Z). The fins 12 always extend on both sides of the plate 10, but here along the axis Y1.

In this embodiment, the thickness of the fins 12 is not constant and their thickness alternates between el equal to 1 mm and e2 equal to 2 mm.

In the examples described here, the fins extend substantially equally from one side of the plate to the other. Nevertheless, they could extend asymmetrically, or even extend only one side of the plate.

By varying the thickness, the spacing, and the offset with respect to the plate for the fins, as well as by choosing a plastic material with the chosen properties, it is possible to obtain a deformation under calibrated constant force. The fins and the plate could also be made of a hybrid plastic material as defined above.

Figures 4 to 7 show variants of the absorber 6 in which it has a cellular architecture. More specifically, this means that the absorber consists of cells oriented substantially in the same direction that can have any shape. On the other hand, the cellular structure can be regular, ie with cells of the same size, or not.

In a general manner, all of FIGS. 4 to 7 represent absorbers 16 seen in the plane (Y1, Z) defined above, the cells constituting them therefore extending in the direction X1. In FIG. 4, the absorber 16 comprises two rows of rectangular cells 18 between which a large cell 20 is provided. The cells 18 and 20 are made of conventional or hybrid plastics material.

The absorber 16 extends over the entire length of the support 4, that is to say over the entire width of the cover C, between projectors of the vehicle.

The size of the cells 18 and the cell 20 is relative as a function of the desired energy absorption. In this configuration, the cell structure is irregular and the cells are substantially rectangular in shape. In the example described here, the cells 18 are hollow and filled with a cellular material, and the cell 20 is full, and the cells 18 have sides of respective dimensions 11 equal to 50 mm and 12 equal to 100 mm. However, these dimensions could be different, for example higher. In addition, the cells 18 and 20 could be identical, ie hollow and filled or not or partially of a cellular material or filled.

FIG. 5 shows a variant of FIG. 4 in which the absorber 16 has a regular structure comprising a row of hexagonal cells 22 of conventional or hybrid plastics material. The cells 22 are connected in pairs by respective sides 24. In the example described here, these cells are full.

Figure 6 shows a variant of Figure 5 in which the cells 22 are hollow. Alternatively, the top of these cells is closed by an end 26 of the same shape, that is to say in the example described here having a total width L and a total height H of 100 mm and a C-edge of 40 mm . However, these dimensions could be different, for example higher.

It is therefore possible to size the absorber 16 by varying the cell geometry, by varying the size of the cells, and by stiffening them by making them full, hollow, filled with cellular material, or hollow and plugged at the end.

Figure 7 shows another embodiment of an abschanger 36 of the invention.

Again the absorber 36 is shown in section in the plane (Y1, Z). The absorber 36 comprises a plurality of tubes 38 of conventional plastic or hybrid material extending in the direction Xl.

The tubes 38 are in the example described here arranged in two rows of tubes 40 and 42, the tubes 38 being within each row separated by a distance 1 here equal to 70 mm. However, this distance could be different, for example higher.

The two rows 40 and 42 are offset relative to one another along the axis Y1 with a height t equal to 100 mm and along the axis Z by a distance i equal to 60 mm, so that that the tubes 38 of the row 40 and those of the row 42 are not at the same level along the axis Yl. However, these distances could be different, for example, higher.

In the example described here, the tubes have a diameter d1 equal to 50 mm. However, this dimension could be different, for example, higher. The tubes 38 of this structure may be hollow 38f, solid 38c, filled with cellular material wholly 38b or partially 38e or closed on top 38a. In addition the tubes 38 could be identical, namely all hollow and filled or not or partially of a cellular material or full and covered or not.

Figure 8 shows another embodiment of an absorber 46 of the invention. In this embodiment, the absorber 46 is constituted by a set of conventional or hybrid plastic bellows segments of generally trapezoidal shape and which are arranged head to tail. These segments 48a, 48b, 48c, 48d are generally designated by the reference numeral 48 and extend as indicated by the reference (X1, Y1, Z). In the example described here, the segments 48 are closed at their end of smaller width. These segments may be hollow 48d, solid 48c, filled with a fully 48b or partially 48a cell material. In addition the segments 48 could be identical, namely all hollow and filled or not or partially of a cellular material or filled.

Figure 9 shows another embodiment of an absorber 56 of the invention. In this embodiment, the absorber 56 is constituted by a hollow body 58 of conventional or hybrid plastic material which extends as indicated by the reference (X1, Y1). In the example described here, this hollow body 58 has walls 60 forming absorbent portions, is fixed on the support 4 by tabs 62 and is filled with a liquid. The body 58 could be left empty.

Figure 10 illustrates by a curve the force transmitted by an absorber according to the invention following an impact with a pedestrian. This effort depends in particular on the level of compression of the absorber as a result of the impact, expressed as a percentage of the ratio x 1 / p where x 1 is the sinker of the absorber (in mm) and p is the depth of the absorber (in mm) measured in the direction Xl.

This effort varies according to three zones of compression of the absorber:

a first transition of said zone, up to about 15%, wherein 1 absorber transmits little effort, and wherein the effort ^'transmitted increases substantially linearly with the level of compression until reaching a threshold chosen effort, for example about 3 kN; a second so-called operating zone, up to about 80%, in which the absorber transmits a substantially constant force, here about 3kN; a third so-called hard zone, up to about 100%, in which the absorber is strongly compressed and ends up constituting a hard point.

In the first zone, the absorber transmits a force substantially linearly proportional to its compression level, which means that the absorber behaves as a substantially constant stiffness spring. In the second zone, the absorber transmits a substantially constant force, irrespective of the level of compression. It therefore offers an apparent stiffness (or "relative" stiffness) substantially zero, relative to its stiffness in the first zone, since the transmitted force does not increase with the level of compression. In the third zone, it exhibits again a substantially constant stiffness until reaching the limit of penetration of the absorber. At this limit, the absorber can no longer absorb and becomes a damaging point for the pedestrian.

In an advantageous embodiment of the invention, the stiffness in the first zone is chosen as large as possible in order to reduce the transition zone, which makes it possible to reach the chosen stress threshold more rapidly. In doing so, the second zone, that is to say the zone of operation of the absorber, is widened, which makes it possible to increase the energy absorbed under constant force during an impact with a pedestrian.

The invention also relates to a front face of motor vehicles comprising one or more devices according to the invention. Figures 11a and 11b show an embodiment thereof.

A front face 100 includes jambs 102, a bumper beam

104, a pedestrian beam 106, an upper rail 108 and projectors 110. The pedestrian beam 106 and the upper rail 108 are disposed on either side of the bumper beam 104, and the side walls 102 are arranged transversely. at their respective ends.

Each of these reinforcements is associated with an absorber 122, 124, 126, 128, 130 respectively corresponding to the side walls 102, to the bumper beam 104, to the pedestrian beam 106, to the upper rail 108 and to the projectors 110. Each of these absorbers is in the example described here with quadrilateral cell structure, but could also be according to one of the architectures described above. In the example described here, the front face is monobloc, that is to say that the elements and absorbetirs are integrated and that the entire front face is integrally molded. The support of the device is here integrated with the frame. They could however be reported on this one.

For the projectors, it is their case which is molded at the same time as the absorber 130.

The description of the examples above is given by way of illustration and not limitation and incorporates in particular any variant that can be imagined by those skilled in the art from the examples above, ie for example the production of a front face incorporating shock devices according to different variants described above.

It is also possible to envisage mixing certain properties of the variants with one another and to provide for example a cellular structure which comprises solid cells, hollow cells completely filled with cellular material, hollow cells partially filled with cellular material, hollow cells and cells. hollow at the end.

The different variants of absorbers described above may be structured and shaped so as to allow the reinforcement and / or the support of a shield of the motor vehicle. They may also allow the guiding of the air.

The skilled person will also consider making several rows of tubes or cells when it is necessary.

All of these variants are to be appreciated in light of the appended claims which follow.

Claims

1. Front face for a motor vehicle, characterized in that it comprises an upper cross member (108) forming an armature, said upper cross member (108) comprising a support (4) which carries an absorber (6; 16; 36; 46; 56) having a plurality of absorbent portions (10, 12; 18, 20; 22, 26; 38; 48; 60) arranged in a geometry selected such that the absorber (6; 16; 36; 46; 56) has , from a threshold of effort chosen, a relative stiffness substantially zero to be able to deform under substantially constant force during an impact.

2. Front face according to claim 1, characterized in that the absorber (6) is a plate (10) supporting a set of fins (12) forming absorbent portions.

3. Front face according to claim 2, characterized in that the plate (10) supports the fins according to their width.

4. Front face according to claim 2, characterized in that the plate (10) supports the fins (12) along their length.

Front panel according to claim 1, characterized in that the absorber (16) is a set of cells (18, 20;

26) forming absorbent portions and having sidewalls (24), each cell (18, 20; 22, 26) having at least one side wall (24) adjoining a side wall (24) of another cell (18). , 20, 22, 26).

6. Front face according to claim 5, characterized in that at least one of the cells (26) has a wall opposite the support.

7. Front face according to claim 6, characterized in that all the cells (26) comprise a wall opposite to the support.

8. Front face according to one of claims 5 to 7, characterized in that the cells have a substantially regular section (22, 26).

9. Front face according to claim 8, characterized in that the section of the cells is hexagonal (22, 26).

10. Front face according to one of claims 5 to 7, characterized in that at least two of the cells have a non-regular section (18, 20).

11. Front face according to claim 10, characterized in that the section of the cells is rectangular (18, 20).

12. Front face according to one of claims 5 to 11, characterized in that the cells are identical (22, 26).

13. Front face according to claims 9 and 12 taken conjointly, characterized in that the cells form a honeycomb (22, 26).

14. Front face according to claims 5 to 11, characterized in that the cells (18, 20) are different two by two.

15. Front face according to claim 1, characterized in that the absorber (36) is a set of tubes (38) forming absorbent portions and having an axis (X) substantially orthogonal to the support.

16. Front face according to claim 15, characterized in that the tubes are hollow.

17. Front face according to claim 16, characterized in that at least one tube has a closed end (38a).

18. Front face according to claim 15, characterized in that the tubes are full (38c).

19. Front face according to one of claims 2 to 4, characterized in that a cellular material is disposed between the fins.

20. Front panel according to one of claims 5 to 14, characterized in that at least one of the cells is filled at least in part with a cellular material.

Front panel according to claim 20, characterized in that at least one cell is completely filled with cellular material.

22. Front panel according to claim 21, characterized in that all the cells are filled entirely with a cellular material.

23. Front face according to claim IS or 17, characterized in that at least one tube (38b) is filled at least in part with a cellular material.

24. Front face according to claim 23, characterized in that all the tubes are filled at least in part with a cellular material.

25. Front face according to claim 24, characterized in that all the tubes are filled entirely with a cellular material.

26. Front panel according to claim 1, characterized in that the absorber (46) is a set of bellows segments (48) arranged head to tail.

27. Front face according to claim 26, characterized in that the segments are empty.

28. Front panel according to claim 27, characterized in that at least one segment is filled at least in part with a cellular material.

Front panel according to claim 28, characterized in that all the segments are completely filled with cellular material.

30. Front face according to claim 1, characterized in that the absorber (56) is a hollow body (58) having walls (60) absorbing.

31. Front face according to claim 30, characterized in that the hollow body (58) is filled with a liquid.

32. Front face according to one of the preceding claims, characterized in that the support and / or the absorbent portions are made of plastic.

33. Front face according to claim 32, characterized in that the plastic material is a hybrid plastic material.

34. Front panel according to one of the preceding claims, characterized in that the support has the general shape of a plate.

35. Front face characterized in that it further comprises at least a second (104) and a third (106) reinforcements.

36. Front face according to one of the preceding claims, characterized in that the second and third armatures are selected from the group consisting of a bumper beam (104), a pedestrian beam (106), a jamb (102) and a projector housing (110).

37. Front face according to claim 36, characterized in that it is made integrally.