EP4259490A1

EP4259490A1 - Assembly for absorbing impact energy

Info

Publication number: EP4259490A1
Application number: EP21823888.9A
Authority: EP
Inventors: Sergio Da Costa Pito; Ali KEZMANE
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2020-12-10
Filing date: 2021-12-03
Publication date: 2023-10-18
Also published as: FR3117428B1; US20240034259A1; WO2022122601A1; CN116568943A; JP2023553627A; FR3117428A1

Abstract

The invention relates to an assembly (10) for absorbing impact energy, comprising a bumper beam and at least one energy absorbing device (1), interposed between this bumper beam (2) and a side member (3) of a motor vehicle, this energy absorbing device, also referred to as a crashbox, comprising a body comprising a plastic material and at least one insert (12) made from composite material comprising a plastic material and a reinforcing filler embedded in this plastic material of the insert, the plastic body and the composite insert being connected in particular by welding, bonding, thermoforming, the insert comprising a region of mechanical weakness (15) arranged to help initiate the breaking of the absorbing device.

Description

TITLE SHOCK ENERGY ABSORBING ASSEMBLY

[1] The present invention relates to a shock energy absorber assembly capable of providing protection in the event of an impact, in particular frontal impact, on a motor vehicle.

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

[3] The present invention aims in particular to improve a shock energy absorber assembly suitable for providing protection in the event of an impact, in particular frontal, on a motor vehicle.

[4] The subject of the present invention is thus an impact energy absorber assembly, comprising a bumper beam and at least one energy absorber device, interposed between this bumper beam and a side member of a motor vehicle, this energy absorber device, also called crashbox in English, comprising a body comprising a plastic material and at least one insert made of a composite material comprising a plastic material and a reinforcing filler embedded in this plastic material of the insert .

[5] For example, the plastic body and the composite inserts are linked in particular by overmolding a material of the same type or compatible.

[6] The insert preferably comprises a zone of mechanical weakness arranged to promote the onset of breakage of the energy absorber device.

[7] The invention thus makes it possible to absorb, in particular in the event of a frontal impact, the maximum impact energy over the entire stroke of the impact without however reaching a peak of force so as not to damage the part of the vehicle. behind the bumper. Thus repair costs can be reduced in the event of an accident and impact.

[8] The presence of a zone of weakness makes it possible, by acting as a break initiator, to avoid/reduce the peak of force that could occur in the event of an accidental impact.

[9] The implementation of the invention does not incur any additional cost, and is easily achievable in a production plant.

[10] According to one aspect of the invention, the weak zone on the insert comprises a notch made on the insert. [11] According to one aspect of the invention, the notch is empty. In other words, this notch corresponds to a hole in the insert.

[12] According to one of the aspects of the invention, the notch receives a filling material, in particular a plastic material.

[13] This filling material is for example the same as that of overmolding, in particular to be compatible with the composite material. This material is for example PP, PA6, PC, PBT.

[14] According to one aspect of the invention, the filling material is different from the material of the rest of the insert.

[15] According to one aspect of the invention, the thickness of the filling material is less than the thickness of the insert.

[16] According to one aspect of the invention, the notch has a round, polygonal or curved shape.

[17] According to one of the aspects of the invention, each insert has a single weak zone.

[18] Alternatively, each insert has a plurality of areas of weakness, in particular a plurality of notches.

[19] For example, the notch has an elongated shape.

[20] According to one aspect of the invention, the insert is formed from a sheet of composite material.

[21] According to one of the aspects of the invention, the reinforcing filler of the insert comprises glass fibres.

[22] According to one of the aspects of the invention, the filling material of the notch can be the same as the plastic material of the body.

[23] According to one of the aspects of the invention, the body has reinforcing ribs, in particular made by molding the plastic material.

[24] According to one aspect of the invention, a plurality of inserts are provided on the body.

[25] According to one of the aspects of the invention, the number of inserts on each body is chosen between 2 and 10, for example between 2 and 6, being for example equal to 6.

[26] Alternatively, a single insert is provided on each body. [27] According to one aspect of the invention, each insert is arranged between two reinforcing ribs of the body.

[28] According to one of the aspects of the invention, the insert or inserts are arranged on the surface of the body of the energy absorber device.

[29] According to one of the aspects of the invention, the body has a perimeter, and the insert extends over only one sector of this perimeter. In other words, the insert is not a coiled strip with its two ends joined.

[30] Another subject of the invention is an energy absorber device comprising a body comprising a plastic material and at least one insert made of a composite material comprising a plastic material and a reinforcing filler embedded in this plastic material of the insert , the plastic body and the composite insert being bonded in particular by welding, gluing, thermoforming.

[31] The plastic material mentioned above can be Polypropylene (PP), High density polyethylene (HDPE), Polyamide (PA), an alloy of polycarbonate polybutylene terephthalate (PC/PBT), polycarbonate (PC), an Acrylate, a Polyurethane, a thermoplastic (TPU).

[32] Other characteristics, details and advantages of the invention will emerge more clearly on reading the detailed description given below, and several embodiments given by way of indication and not limitation with reference to the appended schematic drawings of on the other hand, on which:

[33] [Fig.1] is a schematic view of an assembly according to an example of the invention,

[34] [Fig.2] schematically and partially represents a detail of the assembly according to figure 1.

[35] Motor vehicles are generally equipped with a bumper beam 2 arranged on the front face. As shown in Figure 1, this bumper beam 2 can be attached to two longitudinal members 3 of the vehicle. In order to absorb the shocks and to prevent the energy of the shocks from being directly transmitted to the longitudinal members 3 as well as to the rest of the vehicle, the bumper beam 2 is fixed to energy absorber devices 1 which form the connection between the bumper beam 2 and the ends of the longitudinal members 3 which face said bumper beam 2.

[36] We see in Figure 1 a shock energy absorber assembly 10, comprising the bumper beam 2 and, at two locations of the bumper 2, the two energy absorber devices 1, each interposed between this bumper beam 2 and the associated spar 3. [37] Each energy absorber device 1, also called crashbox in English, comprises a body 11 comprising a plastic material and inserts 12 made of a composite material comprising a plastic material and a reinforcing filler embedded in this plastic material of the insert.

[38] The inserts 12 comprise, for example, carbon and/or glass fibers, this reinforcing material being incorporated into the plastic material. This plastic material can be Polypropylene (PP), High Density Polyethylene (HDPE), Polyamide (PA), an alloy of polycarbonate polybutylene terephthalate (PC/PBT), polycarbonate (PC), an Acrylate, a Polyurethane, a thermoplastic ( TPU).

[39] The inserts 12 are formed from a sheet.

[40] The body 1 1 is made of plastic material which can be polypropylene (PP), high density polyethylene (HDPE), polyamide (PA), an alloy of polycarbonate polybutylene terephthalate (PC / PBT), polycarbonate (PC) , an Acrylate, a Polyurethane, a thermoplastic (TPU).

[41] The plastic body 11 is molded over the inserts 12. The plastic used for the molding is of the same nature or chemically compatible with the resin which impregnates the composite material of the inserts so that strong adhesion is ensured between the body 11 and the inserts 12.

[42] The body 1 1 comprises a plate 13 made in one piece with the rest of the body 1 1 for fixing on the spar 3. This plate 13 has holes 14 for fastening means such as screws on the spar 3 .

[43] Each insert 12 comprises one or more areas of mechanical weakness 15 arranged to promote the onset of breakage of the energy absorber device 1 .

[44] Each zone of weakness 15 on the insert has a notch 16 made on the insert.

[45] In the example described, the notches 16 of the areas 15 are empty. In other words, each notch 16 corresponds to a hole in the insert.

[46] Alternatively, the notch 16 receives a filling material, in particular a plastic material.

[47] The filling material is different from the material of the rest of insert 12.

[48] The thickness of the filling material is less than the thickness of the insert 12.

[49] Each notch 16 has a round shape, polygonal or any curve. [50] One of the inserts may have a single weak zone 15 or a plurality of weak zones 15, thus formed by a plurality of notches. This number can be two, three or more.

[51] In Figure 2, the visible insert 12 has only one weak zone 15.

[52] For example the notch 16 has a slender shape.

[53] Each insert 12 is formed from a sheet of composite material.

[54] Each body 11 has reinforcing ribs 19 made by molding the plastic material. These ribs 19 can be arranged in a cross, or other pattern.

[55] The number of inserts on each body is chosen between 2 and 10, for example between 2 and 6, being for example equal to 6.

[56] For example each insert 12 is arranged between two reinforcing ribs 19 of the body 11, as can be seen for example in Figure 2.

[57] Each insert 12 is arranged on the surface of the body 11 of the energy absorber device, resting on ribs 19 which are located under this insert 12.

[58] The plastic body 11 has a perimeter 18, and each insert 12 extends over only one sector of this perimeter 18. In other words, the insert 12 is not a rolled up strip with its two ends which are joined .

[59] The inserts 12 may all be identical or, alternatively, be different so that the inserts 12 are of different shapes, possibly with a number of areas of weakness which varies from one insert to another.

Claims

[Claim 1] Impact energy absorber assembly (10), comprising a bumper beam and at least one energy absorber device (1), interposed between this bumper beam (2) and a side member ( 3) of a motor vehicle, this energy absorber device, also called a crashbox in English, comprising a body comprising a plastic material and at least one insert (12) made of a composite material comprising a plastic material and an embedded reinforcing filler in this plastic material of the insert, the plastic body and the composite insert being bonded, the insert comprising a zone of mechanical weakness (15) arranged to promote the onset of breakage of the absorber device.

[Claim 2] Assembly according to the preceding claim, in which the zone of weakness (15) on the insert comprises a notch (16) made on the insert.

[Claim 3] Assembly according to the preceding claim, in which the notch (16) is empty.

[Claim 4] Assembly according to claim 2, in which the notch (16) receives a filling material, in particular a plastic material.

[Claim 5] Assembly according to one of Claims 2 to 4, in which the notch (16) has any round, polygonal or curved shape.

[Claim 6] Assembly according to one of the preceding claims, in which the insert is formed from a sheet of composite material.

[Claim 7] Assembly according to one of the preceding claims, in which the body comprises reinforcing ribs (19), in particular produced by molding the plastic material.

[Claim 8] Assembly according to one of the preceding claims, in which a plurality of inserts are provided on the body.

[Claim 9] Assembly according to one of the preceding claims, in which the body has a perimeter, and the insert extends over only one sector of this perimeter.

[Claim 10] Energy absorber device comprising a body comprising a plastic material and at least one insert made of a composite material comprising a plastic material and a reinforcing filler embedded in this plastic material of the insert, the plastic body and the composite insert being linked in particular by welding, gluing, thermoforming.