Rear bumper shield for a motor vehicle incorporating absorption elements

Abstract

The invention relates to a rear bumper shield (1) for a motor vehicle comprising: - a bumper skin (10); and - a plurality of longitudinally extending absorption elements (20) projecting from the inner face of the skin and being rigidly attached to the part or one of the plastic parts constituting this skin, each said absorption element comprising a bridge with a U-shaped cross-section comprising two uprights (21, 22) each attached by a first of their longitudinal ends to the inner face of the skin, as well as an apron (23) connecting the second longitudinal ends of the uprights, the inner face of which apron carries a hollow interface pad (24) intended to face at least one portion of the beam (2) so as to bear against this beam in the event of an impact.

Description

[0001] Description

[0002] Title of the invention: Rear bumper shield for a motor vehicle incorporating absorption elements

[0003] [Technical field]

[0004] [1] The present invention claims priority from French application 2212274 filed on November 24, 2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0005] [2] The present invention relates generally to the field of bumpers for motor vehicles. It relates in particular to a rear bumper shield incorporating absorption elements.

[0006] [Earlier technique]

[0007] [3] Motor vehicles are conventionally provided with a rear bumper shield intended to be mounted on the body structure of a motor vehicle, so as to cover a rear bumper beam extending transversely of the vehicle.

[0008] [4] Such a rear bumper shield comprises a bumper skin made from one or more plastic parts molded from a thermoplastic polymer. It may also comprise, at each of its side parts or crosspieces, internal reinforcement elements fixedly attached by welding or by clipping against this bumper skin.

[0009] [5] Due in particular to the curvature of this rear bumper shield, which is greater than that of the rear bumper beam, a relatively large longitudinal space (which may exceed 100 millimetres) exists between the central area of ​​this shield and the beam.

[0010] [6] The central area of ​​the rear bumper shield being relatively flexible, it tends to sink longitudinally in the event of a light impact or even when simply pressing on it by the user, which significantly affects the perceived quality of the vehicle. [7] In order to obtain a more rigid support feeling and to limit the sinking of the shield in the event of a light impact, it is common to install, between the beam and the rear bumper shield, an elongated energy absorption device generally referred to as a "rear absorber".

[0011] [8] Conventionally molded from a thermoplastic material, this rear absorber is generally fixedly mounted on the rear bumper beam at the edge of the vehicle assembly line.

[0012] [9] However, the addition of such a rear absorber entails design and manufacturing costs which significantly impact the cost price of the vehicle.

[0013]

[0010] Furthermore, its mounting on the rear bumper beam has the consequence of significantly increasing the duration of the vehicle assembly cycle at the line.

[0014]

[0011] In order to overcome these drawbacks, document FR 3 117 429 A1 discloses a rear bumper shield for a motor vehicle comprising a bumper skin and a plurality of absorption elements made in one piece with one of the plastic parts constituting the bumper skin and intended to come opposite the rear bumper beam of the vehicle, so as to bear against said beam in the event of an impact against the outer face of the bumper skin.

[0015]

[0012] These absorption elements are each constituted by a box-shaped imprint made in the skin, so as to form a relief on the side of the inner face of this skin and a hollow on the side of its outer face.

[0016]

[0013] The fact that these absorption elements are integrated directly onto the bumper skin thus makes it possible to optimize the duration of the vehicle assembly cycle at the line edge.

[0017]

[0014] However, and in order to conceal from the outside of the vehicle the hollows formed by these absorption elements on the outer face of the bumper skin, a trim must be attached against the outer face of this skin at the level of the area where these absorption elements are installed, which has a significant impact on the design and manufacturing costs of the rear bumper shield. [Disclosure of the invention]

[0018]

[0015] The present invention aims to improve the situation.

[0019]

[0016] For this purpose, it proposes a rear bumper shield for a motor vehicle comprising:

[0020] - a bumper skin made from one or more plastic parts molded from a thermoplastic polymer, said skin having an inner face intended to face a rear bumper beam of said vehicle as well as an outer face opposite said inner face and intended to be oriented towards the outside of said vehicle; and

[0021] - several absorption elements extending longitudinally projecting from the inner face of said bumper skin and being integral with the part or one of the plastic parts constituting this skin; characterized in that each said absorption element comprises a U-shaped section bridge comprising two legs each attached by a first of their longitudinal ends to the inner face of said bumper skin, as well as an apron connecting the second longitudinal ends of said legs and the inner face of which carries a hollow interface stud intended to be opposite at least a portion of said beam so as to come to bear against this beam in the event of an impact against the outer face of said bumper skin.

[0022]

[0017] This particular configuration of the absorption elements, simply connected by one end of their legs to the inner face of the bumper skin, makes it possible to avoid the presence of hollows on the outer face of this skin so that it is no longer necessary to use a trim to conceal the area where these absorption elements are installed.

[0023]

[0018] The invention therefore makes it possible to optimize the design and manufacturing costs of such a rear bumper shield.

[0024]

[0019] According to preferred characteristics of said rear bumper shield according to the invention:

[0025] - said pads extend in a substantially longitudinal direction and each comprise a tubular main body projecting over a predetermined longitudinal depth; - said tubular main body of each said pad has a rectangular or square section;

[0026] - each said pad comprises a network of stiffening ribs consisting of at least two crossed ribs extending inside the volume formed by its main tubular body and being attached to the inner face of said deck;

[0027] - the thickness of said jambs is reduced at their longitudinal ends connected to the inner face of said bumper skin;

[0028] - the reduction in thickness of the longitudinal ends of said legs connected to the inner face of said bumper skin is between 0.5 and 1.5 millimeters relative to the thickness of the rest of the plastic part constituting said bumper skin and comprising said absorption elements;

[0029] - the connections of said jambs to the inner face of said bumper skin are made along curved zones of change of inclination extending transversely along this skin;

[0030] - said absorption elements are arranged at an identical height while being distributed transversely along the central portion of said bumper skin extending at least over the area where the registration plate of said vehicle is installed; and / or

[0031] - said absorption elements are arranged symmetrically with respect to the median vertical longitudinal plane of said bumper skin.

[0032]

[0020] The invention also relates, in a second aspect, to a motor vehicle comprising such a rear bumper shield.

[0033] [Brief description of the drawings]

[0034]

[0021] The description of the invention will now be continued by the detailed description of an exemplary embodiment, given below for illustrative but non-limiting purposes, with reference to the appended drawings, in which:

[0035] - [Fig 1] represents a three-quarter front perspective view of a rear bumper shield according to the invention;

[0036] - [Fig 2] is an enlargement of detail II of figure 1; and

[0037] - [Fig 3] represents a partial sectional view taken along a vertical longitudinal plane of the rear end of a vehicle on which a rear bumper shield according to the invention is mounted. [Detailed description]

[0038]

[0022] Figure 1 represents a three-quarter rear perspective view of a rear bumper shield 1 according to the invention intended to be mounted on the body structure of a motor vehicle not shown, so as to cover a rear bumper beam 2 extending transversely to the vehicle and partially shown in Figure 3.

[0039]

[0023] In the description which follows and by convention, when reference is made to qualifiers of orientation (such as the terms “vertical”, “transverse” or “horizontal”) or of position (such as the terms “front”, “rear”,

[0040] "upper" or "lower"), the latter will be defined in relation to the normal mounting position of this bumper shield 1 in a vehicle and following the ordinary direction of progression of the latter.

[0041]

[0024] The terms "external" and "internal" will be used to define the relative position of an element with reference to the median vertical longitudinal plane of the vehicle. The element closest to this plane will thus be described as internal as opposed to the other element further from this same plane which will be described as external.

[0042]

[0025] Finally, the term "substantially" will indicate that a slight deviation is permitted from a predetermined nominal position or arrangement, while remaining included within the scope of the invention. For example, "substantially vertical" indicates that a deviation of the order of 15 to 20° from a strictly vertical orientation is permitted within the scope of the invention.

[0043]

[0026] The bumper shield 1 comprises a bumper skin 10 made from one or more plastic parts molded from a thermoplastic polymer such as Polypropylene (PP), Polyethylene (PE), polyamide (PA), Acrylonitrile Styrene Acrylate (ASA) or Acrylonitrile Butadiene Styrene / Polycarbonate (ABS / PC), possibly reinforced with natural and / or synthetic fibers.

[0044]

[0027] With reference to Figure 3, this bumper skin 10 has an inner face 10A intended to come opposite the rear bumper beam 2 of the vehicle, as well as an outer face 10B opposite the inner face 10A and intended to be oriented towards the outside of the vehicle.

[0028] As illustrated in Figure 1, the bumper shield 1 also comprises several absorption elements 20 (six in this case) extending longitudinally projecting from the inner face 10A of the bumper skin 10 and intended to come opposite the rear bumper beam 2, so as to bear against the latter in the event of impacts against the outer face 10B of the skin 10.

[0045]

[0029] In order to limit the cost price of the bumper shield 1, the absorption elements 20 are made in one piece (i.e. from a single block) with the part or one of the plastic parts constituting the bumper skin 10.

[0046]

[0030] Arranged at an identical height, these absorption elements 20 are distributed transversely along the central portion of the bumper skin 10, extending at least over the area where the vehicle's registration plate is installed and advantageously over more than half the width of this vehicle.

[0047]

[0031] Advantageously, these absorption elements 20 are arranged symmetrically with respect to the median vertical longitudinal plane of the bumper skin 10, being preferentially distributed in a substantially regular manner along this central portion of the skin 10.

[0048]

[0032] According to the invention and with reference to Figures 2 and 3, each absorption element 20 is constituted by a U-shaped section bridge comprising two upper 21 and lower 22 legs each attached by a first of their longitudinal ends to the inner face 10A of the skin 10, as well as an apron 23 connecting the second longitudinal ends of these two legs 21, 22 and the inner face of which carries a hollow interface stud 24 intended to be opposite at least one portion of the beam 2 (here its upper portion as illustrated in Figure 3) so as to come to bear against this beam 2 in the event of an impact against the outer face 10B of the bumper skin 10.

[0049]

[0033] This particular configuration of the absorption elements 20, simply connected by one end of their legs 21, 22 to the inner face 10A of the bumper skin 10, makes it possible to avoid the presence of hollows on the outer face 10B of this skin 10 so that it is no longer necessary to use a trim to conceal the area of ​​implantation of these absorption elements 20.

[0034] Extending in a substantially longitudinal direction, the hollow studs

[0050] 24 of the absorption elements 20 each comprise a tubular main body

[0051] 25 advantageously having a rectangular or square section and projecting over a predetermined longitudinal depth.

[0052]

[0035] This depth can be easily adjusted by removing or adding material in the injection mold used to manufacture the plastic part in which these studs are made, so as to adjust the spacing between these studs 24 and the beam 2 after the shield 1 has been put in place (this spacing being for example between 2 and 10 millimeters).

[0053]

[0036] In order to improve their mechanical rigidity, the pads 24 each comprise a network of stiffening ribs consisting of at least two crossed ribs 26 extending inside the volume formed by this tubular main body 25 and being placed against the inner face of the apron 23.

[0054]

[0037] It will be noted that the excess thickness of material necessary for the creation of the legs 21, 22 could cause, at the time of molding the plastic part comprising the absorption elements 20, a shrinkage of material on the outer face 10B of the bumper skin 10 during the cooling of the material after injection.

[0055]

[0038] This shrinkage of material, commonly referred to as “shrinkage”, thus causes slight surface defects on the outer face 10B of the bumper skin 10.

[0056]

[0039] In order to limit the risks of such shrinkage appearing on the outer face 10B of the bumper skin 10 at the connection zones of the legs 21, 22 of the absorption elements 20, it will be noted with reference to FIG. 3 that the thickness of these legs 21, 22 is advantageously reduced at their longitudinal ends connected to the inner face 10A of the bumper skin 10.

[0057]

[0040] This reduction in thickness will for example be between 0.5 and 1.5 millimeters relative to the thickness of the rest of the plastic part constituting the bumper skin 10 and comprising the absorption elements 20, so that for a conventional injection thickness of approximately 3 millimeters, the local thickness at the connection ends of the legs 21, 22 is between 1.5 and 2.5 millimeters.

[0058]

[0041] Still with the same objective of limiting the risks of the appearance of such shrinkages on the outer face 10B of the bumper skin 10 at the connection zones of the legs 21, 22 of the absorption elements 20, it will also be noted in support of this figure 3 that the connections of these legs 21, 22 to the inner face 10A of the bumper skin 10 are made along curved zones of change of inclination 11, 12 extending transversely along this skin 10.

[0042] According to variant embodiments not shown, the number and / or the arrangement of the absorption elements 20 may vary.

[0059]

[0043] According to other embodiment variants not shown, the hollow interface pads 24 can also be shaped differently depending on the circumstances and in particular the profile of the beam 2.

[0044] Finally, it is recalled that the present invention is not limited to the embodiments described and shown, but also encompasses all the execution variants within the reach of those skilled in the art, i

Claims

Claims

1. Rear bumper shield (1) for a motor vehicle comprising: - a bumper skin (10) made from one or more plastic parts molded from a thermoplastic polymer, said skin (10) having an inner face (10A) intended to face a rear bumper beam (2) of said vehicle as well as an outer face (10B) opposite said inner face (10A) and intended to be oriented towards the outside of said vehicle; and - several absorption elements (20) extending longitudinally projecting from the inner face (10A) of said bumper skin (10) and being integral with the part or one of the plastic parts constituting this skin (10); characterized in that each said absorption element (20) comprises a U-shaped section bridge comprising two legs (21, 22) each attached by a first of their longitudinal ends to the inner face (10A) of said bumper skin (10), as well as an apron (23) connecting the second longitudinal ends of said legs (21, 22) and the inner face of which carries a hollow interface pad (24) intended to be opposite at least a portion of said beam (2) so as to come to bear against this beam (2) in the event of an impact against the outer face (10B) of said bumper skin (10).

2. Rear bumper shield (1) according to claim 1, characterized in that said studs (24) extend in a substantially longitudinal direction and each comprise a tubular main body (25) projecting over a predetermined longitudinal depth.

3. Rear bumper shield (1) according to claim 2, characterized in that said tubular main body (25) of each said stud (24) has a rectangular or square section.

4. Rear bumper shield (1) according to one of claims 2 or 3, characterized in that each said stud (24) comprises a network of stiffening ribs consisting of at least two ribs crossed (26) extending inside the volume formed by its tubular main body (25) and being leaning against the inner face of said apron (23).

5. Rear bumper shield (1) according to one of claims 1 to 4, characterized in that the thickness of said legs (21, 22) is reduced at their longitudinal ends connected to the inner face (10A) of said bumper skin (10).

6. Rear bumper shield (1) according to claim 5, characterized in that the reduction in thickness of the longitudinal ends of said legs (21, 22) connected to the inner face (10A) of said bumper skin (10) is between 0.5 and 1.5 millimeters relative to the thickness of the rest of the plastic part constituting said bumper skin (10) and comprising said absorption elements (20).

7. Rear bumper shield (1) according to one of claims 1 to 6, characterized in that the connections of said legs (21, 22) to the inner face (10A) of said bumper skin (10) are made along curved zones of change of inclination extending transversely along this skin (10).

8. Rear bumper shield (1) according to one of claims 1 to 7, characterized in that said absorption elements (20) are arranged at an identical height while being distributed transversely along the central portion of said bumper skin (10) extending at least over the area of ​​implantation of the registration plate of said vehicle.

9. Rear bumper shield (1) according to one of claims 1 to 8, characterized in that said absorption elements (20) are arranged symmetrically with respect to the median vertical longitudinal plane of said bumper skin (10).

10. Motor vehicle comprising a rear bumper shield (1) according to one of claims 1 to 9.

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