EP3676130A1

EP3676130A1 - Small-impact absorber

Info

Publication number: EP3676130A1
Application number: EP18759122.7A
Authority: EP
Inventors: Thierry Roussel; Stéphane Ginja
Original assignee: Plastic Omnium SE
Current assignee: Plastic Omnium SE
Priority date: 2017-09-01
Filing date: 2018-08-30
Publication date: 2020-07-08
Also published as: WO2019043090A1; MA50024A; FR3070646A1

Abstract

The invention relates to a motor vehicle impact absorption module, comprising a rigid structure, that is to say a structure that does not deform under the effect of a small impact, intended to be positioned on the vehicle such that a front face of the rigid structure is located facing an internal face of a body skin, the module comprising a small-impact absorber formed by a corrugated web overmoulded on the front face of the rigid structure, perpendicularly to this rigid structure.

Description

ABSORBER OF SMALL SHOCKS

The invention relates to an energy absorber and an assembly consisting of an energy absorber and a rigid structure.

The invention has been designed in particular, although not necessarily only, to be useful in the case of parking shocks or pedestrian shocks. In the present description collectively, parking shocks and pedestrian shocks are collectively referred to as "small shocks". "Small shocks" are shocks with low kinetic energy sent, less than 1000 J, and to dissipate in the vehicle.

The following description of the prior art is intended to facilitate the understanding of the present invention only. The discussion is not an acknowledgment or admission that one of the documents mentioned is part of the general knowledge common to the priority date of the application.

Management of shocks that can occur on the body of a moving vehicle is a key factor for the automotive industry, insurers and users: we seek optimal security, whether for the protection of occupants and pedestrians, only for the preservation of the body or for simplified repair for small shocks.

Insurers seek in particular to know the impact of a collision to estimate the cost and calculate insurance premiums based on the price of repairs, and bodily injury resulting from different types of shocks likely to occur.

In practice, professionals in the automotive sector have defined several types of shocks for which they are constantly trying to propose solutions to reduce the consequences of a shock.

[0007] Shock reference standards have been established, which all new vehicles must respect, including all RCAR (Research Council for Automotive Repairs) crash tests that are a reference in the automotive sector. RCAR is a global association of insurance company research centers dedicated to improving vehicle safety, damage, repairability and safety.

[0008] There are four main types of shocks:

High speed shocks correspond to frontal shocks against an obstacle at a speed of approximately 60km / h,

"insurance" or "Danner" shocks, at 15 km / h against a fixed wall, - "parking" shocks at low speed, below 10km / h, defined by the ECE 42 standard in Europe.

pedestrian shocks: 40km. h ^"1 but at low energy (<1000 J). pedestrian impact on the leg, it is the flexibility of the body that can best absorb this type of shock by limiting the damage to the body of a pedestrian (leg, hip, head).

To handle the shocks of the first two categories listed above, a shock module comprises a horizontal rigid structure called shock beam, coupled to insurance shock absorbers called crash boxes.

To manage the last two categories of shocks, collectively referred to as small shocks, ie low energy shocks (less than 1000 J) that are pedestrian shocks and parking shocks, a combination of structures is often used: to absorb the energy of parking shocks, an absorber is located between the skin of the body and the rigid structure. It can be made of injected plastic material or foam (PPE: expanded polypropylene).

A possibility to replace this combination is proposed in EP 1 350 680 B1 entitled "Energy absorber for interposing between a rigid structure and a bumper skin".

This is an extension to a shock absorber module incorporating the structure and its insurance shock absorbers, called crash boxes. Said extension performs the function of a small shock absorber. A shock absorber module is a set of elements whose association is intended to absorb all the shocks of different energies that a vehicle is likely to undergo, in order to minimize the consequences of these shocks.

Even if the device shown in EP 1 350 680 B1 can replace two devices by one, thus reducing costs, simplifying its implementation and decreasing the thickness required for installation, it has a lack of stability in the case of a shock having a lateral or vertical component: with such a shock, the device tends to slide along the rigid structure, which does not provide a good damping effect, and this lack of resistance causes a relative fragility of the bumper vis-à-vis a shock partly lateral. A shock with a vertical component may not be damped with great efficiency either, because of a slippage of the ribs on the bumper skin and in particular the rib intended to flare in the event of a frontal impact . In addition, even for a frontal impact, the device does not always give the expected results because the behavior of the device is rarely exactly the one for which it was sized, since it flames too easily when it is desired that it compresses locally absorbing a maximum of energy.

WO03072399.A2 discloses a bumper assembly for a motor vehicle front face with an energy absorber in the form of a lamella fixed projecting on a rigid element towards the front of the vehicle, along a horizontal line, inclined or not in one direction or the other, in order to absorb shocks with a pedestrian at a lower cost.

Finally, the document US2009160203.A1 has a shock absorber for absorbing shocks with pedestrians. This absorber is mounted on the front face of a motor vehicle and comprises two transverse vertical walls interconnected by ribs.

The invention aims to overcome these disadvantages by providing a continuous device just as simple and economical to set up, but which provides great stability to the shock absorber, regardless of the angle of impact. to which it is subject: purely frontal, or partially oblique.

The object of the invention is a shock absorption module for a motor vehicle, comprising a rigid structure, that is to say a structure that does not deform under the effect of a small shock, intended to be positioned on the vehicle so that a front face of the rigid structure is facing an inner face of a body skin, said module comprises a small shock absorber consisting of a mold overmolded on the face front of the rigid structure, perpendicular to the rigid structure, the web is corrugated, that is to say that it is generated by translation of parallel generatrices in a directionally alternating increasing and decreasing curve along the front face of the rigid structure.

To understand the device, some explanations of the present description are limited to shocks on the front of a vehicle, but the device of the invention can be implemented to absorb shocks on other parts the body of a vehicle, including the rear part of a vehicle.

According to the invention, the term "alternately increasing and decreasing curve" means a curve which is carried by a generally planar bearing surface and which is alternately on one side and the other of the straight line of linear regression. said curve.

According to the invention, the term "globally flat surface" means a surface that is either mathematically plane or locally assimilable to a mathematically spherical or cylindrical surface but with a large radius of curvature so that the bending of the surface does not prevent to consider it locally as flat.

According to the invention, the term "perpendicular", forming an angle of 90 °, with a tolerance of several tens of degrees, "perpendicular" means at least all angles between 75 ° and 105 °. According to the invention, the term "a veil" a material plate, that is to say whose length and width are much larger than the thickness and a veil is corrugated when it is generated by translation of parallel generatrices in a directional curve alternately increasing and decreasing along the front face of the rigid structure.

According to the invention, the term "width of a web" the dimension of said web along the X axis.

According to a first embodiment, the guide curve is a sinusoid, which has the advantage of avoiding the buckling of the web in case of compression. Indeed, the corrugations provide stability in compression, compared to horizontal lamellae.

According to a first variant of this embodiment, the guide curve of the shock absorber module is a sinusoid of minimum frequency to the middle of said rigid structure.

The greater the amplitude, the more the device is effective, the further away from the middle of the device, the width of the web must be reduced in order to fit the curve of the vehicle. This reduction in web width results in a reduction in the absorption capacity of small impacts, which can be compensated for by increasing the frequency of the sinusoidal shape of the web as the width of said web decreases. Thus, the resistance to deformation of the wavy web may be identical along its longitudinal axis, and the shape of the web remains compatible with the front curve of the vehicle.

The steering curve may be a regular sinusoid of constant amplitude and frequency (alternative not shown), which has the advantage of controlling the mechanical response of the device.

According to a second variant of this embodiment, the shock absorption module comprises strictions distributed along a web.

This embodiment has the advantage of creating areas of weakness along the wavy veil, strictions whose number and thickness can calibrate the density of the absorber according to the energy we are looking for. to absorb. These zones of weakness are as many deformation initiation zones which make it possible to program the deformation and / or the rupture of the absorber to absorb the energy of small shocks.

According to a third variant of this embodiment, the shock absorption module has a shock absorbing capacity that can be adapted through the thickness of the veil, thanks to the width of the veil, thanks to the frequency of the undulations of the veil and thanks to the shape of said undulations, the wave form can be one of a sinusoid, a niche and broken lines.

This embodiment has the advantage of being able to calibrate the shock absorber according to the power of the shocks we are trying to absorb.

According to a fourth variant of this embodiment, the shock absorption module has a symmetrical web with respect to the center of a front face of a rigid structure.

This embodiment has the advantage of absorbing small shocks uniformly on each side of the front face.

According to a fifth variant of this embodiment, the shock absorption module is positioned at least partly behind a license plate.

This embodiment has the advantage of protecting the bumper skin from the risk of marking in the event of frontal impact at very low speed, ie less than 4km / h.

According to a fifth variant of this embodiment, the shock absorption module has a corrugated web positioned in place of certain air guide partitions.

This embodiment has the advantage of removing part of a part, which reduces the weight, cost and complexity of the realization of the final vehicle.

According to a sixth embodiment, the shock absorption module according to one of the preceding claims, with several corrugated sails positioned at different levels in a vertical plane on a front face of a rigid structure considering said structure. rigid in its final assembled position.

This embodiment has the advantage of being able to calibrate the shock absorber according to the power of the shocks we seek to absorb through this device, as well as to distribute the energy of a shock on several vertically aligned points, which spread the impact of the impact on a pedestrian's body at several points, reducing the risk of injury.

To implement the method of the invention, one can use a specific molding tool, which is one of the objects of the present invention.

This molding tool comprises overmolding means which allows continuous overmoulding on a rigid structure, that is to say a structure that does not deform under the effect of a small shock, at least one veil corrugated, that is to say that said web is generated by translation of parallel generatrices in a directionally alternating increasing and decreasing curve along the front face of the rigid structure, perpendicular to said front face. To manufacture the device of the invention, one can use a specific procedure, which is one of the objects of the present invention.

This procedure allows overmoulding by injection of material on a rigid structure, that is to say a structure that does not deform under the effect of a small shock, a wavy veil, that is to say that said web is generated by translation of parallel generatrices in an alternating and decreasing directional curve along the front face of the rigid structure.

We will now present an embodiment of the invention given by way of non-limiting example and with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a shock absorption module 1 for a motor vehicle,

FIG. 2 is an enlargement of zone II of FIG.

The shock absorber module 1 is positioned at the front of the vehicle, in front of the engine block (not shown), under the body skin (not shown), and is fixed on the longitudinal members (not shown) which are part of of the chassis.

The shock absorber module 1 comprises two crash boxes 2 each positioned at one end of a rigid structure 3 on a rear face of the rigid structure 3. Said rear face is not visible on the 3D view of the figure 1 . The said crash boxes 2 are fixed in the continuity of the side members. The rigid structure 3 has a front face 4. Said front face 4 has a W-shaped section turned 90 ° forming a coated W. The coated W-shape is created from alternately horizontal and vertical portions whose surface is generally planar, said portions define seven alternately horizontal and vertical planes, thus creating two crenellations that surround a flat bottom groove.

According to the invention, the outer surfaces of said flat bottom grooves are collectively referred to as the "front face" and the flat bottom of said groove is called "vertical surface". Starting from the top to the bottom, the front face therefore has an upper front face 5, a vertical surface 6 and a lower end face 7.

The vertical surface 6 is reinforced by a network of overmolded ribs 8 that strengthen the rigid structure 3. This network of ribs 8 is a triangular mesh network which extends over a length smaller than the total length of the rigid structure 3 and which is centered at Y0 along a longitudinal axis. In the embodiment shown, the network of ribs 8 is not a web (that is to say a corrugated plate) within the meaning of the invention. Alternatively, the network of ribs 8 may be a haze within the meaning of the invention, as explained at the end of the description with respect to an embodiment not shown. Behind the rigid structure 3 is the part of the vehicle that supports the radiator, not shown.

Legs 9, integral with the rigid structure 3, extend downward (in the use position of the module), just next to the crash boxes. The legs 9 extend under said rigid structure 3 and support a horizontal low support 10 which forms a convergent, that is to say an air guide which helps channel air entering the radiator (not shown) by the air inlet 1 1 located under the rigid structure 3. The convergent extends laterally to the wing supports (not shown). Due to its hollow shape, the convergent has a certain rigidity which allows it to constitute a low path of pedestrian shock absorption, as is known. This is why the convergent is an integral part of the shock absorption module 1.

On the lower end face 7 of the rigid structure 3, is fixed horizontally, by overmolding, a main web 12, for the absorption of small shocks. According to this embodiment, the main web 12 has a vertical sinusoidal section with a higher frequency near the ends than in the center of the rigid structure 3. The densification of the main web 12 is thus higher on the sides of the rigid structure 3 in the middle of the rigid structure. The overmolding is carried out by injection under pressure of material in a mold whose footprint resumes, in hollow, the shape of the main veil 12 with restrictions 13.

These restrictions 13 are visible by approaching the main sail 12, as can be seen in Figure 2. Similarly, we see material strips 14 placed against the structure which ensure the continuous attachment of the main sail 12 with intervals between said bands. Said strips ensure the continuous attachment between the main web (corrugated plate) 12 perpendicularly to the lower end face 7 of the rigid structure 3.

In Figure 1, two other secondary webs 15 are fixed by overmoulding on the upper end face 5 of the rigid structure 1, at the ends of said end faces, perpendicular to the rigid structure 1, in addition to the main sail 12 positioned on the lower end face 7 of the front face 4. These secondary sails 15 can enhance the ability to absorb small impacts on the sides of the module.

[00054] All the sails 12 and 15 have a sinusoidal section. The amplitude of the sinusoid is as great as possible, the width along the X axis of the webs 12 and 15 decreases in the direction that goes from the center to the sides of the device in order to follow the curve of the vehicle. To compensate for the decrease on the sides of the width of the webs 12 and 15, the frequency of the sinusoidal shape that the webs 12 and 15 follow is increased towards the sides of the device. In the embodiment shown, there is continuity of material between the webs and the strips of material laid.

In addition to its small shock absorption function, the main sail 12 acts as an air guide partition vis-à-vis the air inlet 1 1 located under the rigid structure 3.

The invention is not limited to the embodiments presented and other embodiments will become apparent to those skilled in the art. It is possible in particular to set up such a device at the rear of a vehicle to absorb small shocks that may occur in the case of a reverse of the vehicle.

In an embodiment not shown, the network of ribs 8 extends towards the front of the vehicle along the X axis, beyond the upper end face 5 and the lower end face 7. The ribs s' stop at the same level as the webs 12 and 15 and the network of ribs 8 thus extended forward also constitutes a haze within the meaning of the invention, capable of providing the energy absorber function for small shocks.

It is also possible to replace the sinusoidal shape of the veil by any other form or combination of form:

triangular shape with a succession of inclined planes which connect with circular shapes of radius much smaller than the length of the inclined planes,

- slot form, etc.

References used in the drawings

• shock absorption module 1

• crash boxes 2

• rigid structure 3

• front face 4

• upper face 5

• vertical surface 6

• bottom face 7

• network of ribs 8

• jambs 9

• horizontal low support 10

• air inlet 1 1

• main sail 12

• restrictions 13 • strips of materials laid 14

• secondary sails 15

Claims

claims

1. Shock absorbing module (1) for a motor vehicle, comprising a rigid structure (3), ie a structure that does not deform under the effect of a small shock, intended to be positioned on the vehicle so that a front face (4) of the rigid structure (3) is facing an inner face of a body skin, said module comprises a small impact absorber consisting of a web (12; ) molded on the front face (4) of the rigid structure, perpendicular to the rigid structure (3), the web (12; 15) is corrugated, that is to say that it is generated by translation of parallel generatrices in an alternatingly increasing and decreasing directional curve along the front face (4) of the rigid structure (3), and said absorption module having constrictions (13) distributed along said web (12; 15).

2. shock absorbing module (1) according to the preceding claim, wherein the guide curve is a sinusoid of minimum frequency to the middle of said rigid structure (3).

3. shock absorbing module according to one of the preceding claims, the shock absorbing capacity may be different in different areas depending on the thickness of the web (12; 15), the width of the web, of the frequency of the undulations of the web (12; 15) and the shape of said undulations, the waveform may be one of a sinusoid, a square and broken lines.

4. shock absorbing module according to one of the preceding claims, with a web (12) symmetrical with respect to the center of a front face (4) of a rigid structure (3).

5. shock absorbing module (1) according to one of the preceding claims, adapted to be positioned at least partly behind a license plate.

6. shock absorbing module (1) according to one of the preceding claims, a corrugated veil (12) is adapted to be positioned in place of certain air guide partitions.

7. shock absorbing module according to one of the preceding claims, with several corrugated webs (12; 15) positioned at different levels in a vertical plane on a front face (4) of a rigid structure (3) considering said rigid structure (3) in its final assembled position.

8. A method for manufacturing a shock absorbing module (1) according to any one of claims 1 to 7 for overmoulding by injection of material on a rigid structure (3), ie a structure which does not deform under the effect a small shock, a corrugated veil (12; 15), that is to say that said veil (12; 15) is generated by translation of parallel generatrices in a directionally alternating increasing and decreasing curve along the face frontal (4) of the rigid structure (3).

9. A molding tool for implementing the method according to claim 8, comprising overmoulding means which allows to overmold continuously on a rigid structure (3), ie a structure that does not deform under the effect of a small impact, at least one corrugated veil (12; 15), that is to say that said veil (12; 15) is generated by translation of parallel generatrices in a directionally alternating curve and decreasing along the front face (4) of the rigid structure (3), perpendicular to said front face (4).