Front cradle of an electric motor vehicle

Abstract

The invention relates to a front cradle for an electric motor vehicle comprising: - a rear crossmember (12) adapted to be installed transversely in line with a motor vehicle chassis, said rear crossmember having two opposing lateral ends (14, 16); - two beams (18, 20) connected respectively to said two lateral ends (14, 16), said two beams extending along a horizontal component perpendicular to said rear crossmember (12) and opposite said chassis; and, - two body supports (30, 32) erected respectively on said two beams (18, 20) in the vicinity of said rear crossmember. It also includes a supplementary U-shaped crossmember (28) having two opposing arms (30, 32) forming said two body supports respectively, said supplementary U-shaped crossmember resting on said two beams (18, 20) parallel to said rear crossmember (12). Figure to be published with the abbreviation: Fig. 1

Description

Title of the invention: Front cradle for an electric motor vehicle

[0001] The present invention relates to a new front cradle for an electric motor vehicle.

[0002] Motor vehicles are now evolving towards technologies with a lower carbon footprint. As a result, the internal combustion powertrains that have equipped them so widely until now are being replaced by electric powertrains.

[0003] Naturally, traditional motor vehicle manufacturers initially began by substituting electric motors for internal combustion engines in traditional vehicle frames.

[0004] However, the chassis and bodies of motor vehicles with a thermal powertrain are generally adapted to accommodate a relatively heavy internal combustion engine at the front and a relatively light and compact fuel tank at the rear.

[0005] Conversely, vehicles with an electric powertrain have a relatively compact and lighter electric motor at the front. However, relatively heavy batteries must be installed at the rear of the vehicle or even underneath it. Therefore, the chassis structure must be modified and reinforced.

[0006] Consequently, the structure of the vehicles had to be redesigned to better support this new distribution of masses inside the vehicle, on the one hand, but also to organize differently the routing of the control and power supply cables of the electric powertrain.

[0007] Also, the fixing points of the electric powertrain must be moved relative to a thermal engine and must be filtered differently because the vibrations are less but, on the other hand, the engine frequencies are higher.

[0008] There is therefore a need for a new front cradle specifically adapted to receive an electric powertrain.

[0009] To this end, a front cradle for a motor vehicle is proposed comprising:

[0010] - a rear crossmember adapted to be installed transversely in the extension of a motor vehicle chassis, said rear crossmember having two opposing lateral ends;

[0011] - two beams connected respectively to said two lateral ends, said two beams extending along a horizontal component perpendicular to said rear crossmember and opposite said chassis; and,

[0012] - two crate supports erected respectively on said two beams at in the vicinity of said rear crossmember.

[0013] The front cradle includes a supplementary U-shaped cross member having two opposing arms forming respectively said two body supports, said supplementary U-shaped cross member resting on said two beams parallel to said rear cross member.

[0014] Thus, a feature of the invention lies in the implementation of a complementary U-shaped crossmember which makes it possible to create the two body supports, otherwise known as "horns". These two body supports, together with the two beams and the rear crossmember, form a more rigid assembly.

[0015] Moreover, and according to a particularly advantageous embodiment of the invention, said additional U-shaped cross member includes a clevis located substantially equidistant from said two branches in order to anchor the electric powertrain of the motor vehicle.

[0016] In other words, the additional U-shaped cross member allows a clevis to be attached between the two body supports, in order to create a new anchor point for the electric powertrain.

[0017] Advantageously, said clevis receives a silent block to filter vibrations between said powertrain and said complementary U-shaped crossmember. Thus, the silent block allows both the filtering of vibrations, but also the anchoring of the powertrain.

[0018] Furthermore, according to a particularly advantageous embodiment of the invention, said cleat comprises two U-shaped profiles placed back to back and extending opposite each other, mounted on said complementary cross member. The two U-shaped profiles are welded back to back to the cross member and together form a rigid cleat.

[0019] Advantageously, said complementary U-shaped cross member is hollow. Therefore, it is relatively light, but nevertheless, it exhibits high rigidity.

[0020] According to a preferred embodiment of the invention, said complementary U-shaped cross member is produced by bending and stamping a metal plate. It is, for example, made from a steel plate.

[0021] After bending and stamping, the edges are welded together to close the cross member. Thus, such a cross member can be produced at an advantageous cost.

[0022] Furthermore, and according to another particularly advantageous embodiment of the invention, said two arms of said complementary U-shaped cross member have a triangular shape. In this way, the two arms forming the body supports are more rigid.

[0023] Also, the crossbar is hollow and therefore the two branches have a triangular prismatic shape as will be explained in more detail later in the description.

[0024] Advantageously, according to the invention, each of the apexes of said branches has a seat for receiving an anchor sleeve oriented along a component perpendicular to said rear crossmember and said beams, and said anchor sleeve is connected to the apex of said branch by welding. In other words, the anchor sleeve is oriented along a vertical component. Also, its seat, at the apex of the branches, has a semicircular cylindrical surface against which it bears.

[0025] Preferably, and according to the invention, said anchor sleeve is connected to the top of said branch by at least two weld beads of a predetermined length along two opposite generatrices of said anchor sleeve.

[0026] The bushings receive screws to anchor the vehicle body. In the event of a collision, it is necessary, for safety reasons, that the body and the tops of the body supports separate. Therefore, the length of the two weld beads securing the bushings to the tops of the supports is predetermined so that these welds can break upon impact at a specific energy threshold. The length of the weld beads is adjusted according to the different types of models produced on the same platform.

[0027] Furthermore, the front cradle according to the invention comprises a front crossmember connecting said beams together, at a distance and substantially parallel to said rear crossmember. Thus, the rear crossmember, the two beams, and the front crossmember form a trapezoidal frame. Also, the front crossmember receives, according to the invention, another bracket for anchoring the electric powertrain. Such another bracket also allows for the filtering of unwanted frequencies.

[0028] Other features and advantages of the invention will become apparent from the following description of particular embodiments of the invention, given by way of example but not limitation, with reference to the accompanying drawings in which:

[0029] [Fig. 1] is a schematic perspective view of a front cradle of an electric motor vehicle according to the invention;

[0030] [Fig.2] is a schematic detail view of the object of [Fig.1] according to a mode execution; and,

[0031] [Fig.3] is a schematic detail view of the object of [Fig.1] according to another mode execution.

[0032] Fig. 1 shows, viewed from ¾ rear left perspective, a front cradle 10 of a motor vehicle according to the invention.

[0033] It is inscribed in an orthogonal X, Y, Z frame of the motor vehicle, in which the X axis extends along a front-to-back longitudinal direction, oriented towards the rear; The Y axis extends along a transverse direction of the vehicle, oriented from left to right when in normal driving conditions; and the Z axis extends along a vertical direction, oriented away from the ground.

[0034] The front cradle 10 includes a rear cross member 12 adapted for mounting on a motor vehicle, not shown, and extending along a transverse direction D of the vehicle. The rear cross member 12 is made of a stamped metal plate, folded and welded to form a hollow beam.

[0035] Also, it has two opposite ends, a right end 14 and a left end 16.

[0036] The front cradle 10 also includes two beams, a straight beam 18 connected to the right end 14 of the rear cross member 12 and a left beam 20 connected to the left end 16 of the rear cross member 12.

[0037] The two beams, right 18, left 20, extend along a horizontal component perpendicular to the transverse direction D. In other words, the beams 18, 20 extend horizontally towards the front of the vehicle. Also, they extend at a significantly different angle from each other.

[0038] On the other hand, the rear cross member 12 and the beams 18, 20 are connected to the vehicle chassis, in particular by means of rear screwing members 24, 26, oriented vertically.

[0039] The front cradle 10 also includes a first front cross member 22, connecting the two beams 18, 20 at a distance from the rear cross member 12 and extending substantially parallel to the latter. In addition, a second front cross member 25 connects the ends of the two beams 18, 20 and extends substantially parallel to the first front cross member 22.

[0040] Also, in accordance with the invention, the front cradle 10 also includes a complementary U-shaped cross member 28, installed transversely, along the rear cross member 12 and supported on the two beams 18, 20.

[0041] The complementary U-shaped cross member 28 comprises two opposing branches, a right branch 30, and a left branch 32, as well as a bottom portion 34 which connects them.

[0042] The additional cross member 28 is obtained by stamping and bending a metal plate, for example made of steel, and by welding its edges. This allows it to be obtained at an advantageous cost.

[0043] Consequently, the complementary cross member 28 is hollow, and therefore relatively light.

[0044] The two opposing branches 30, 32 have a general triangular prismatic shape. And the complementary U-shaped cross member 28 has two parts, a right part 35 and a left part 36, symmetrical to each other with respect to an axial median plane Pm.

[0045] Thus, each of the two opposing branches 30, 32 has a horizontal slice 38, extending from the bottom portion 34 and resting on the corresponding beam. It also has a substantially vertical slice 40 and an inclined slice 42, converging towards each other up to a vertex 44. And these three slices are connected together by a rear triangular flank shown in [Fig. 1] and an opposite front triangular flank, which is hidden here.

[0046] The vertex 44 of the two opposing branches 30, 32 supports the body of the motor vehicle, which is not shown here. The vertex 44 of the two branches 30, 32 will be described in detail later with reference to [Fig.2] and [Fig.3].

[0047] Also, the complementary U-shaped cross member 28 is made fixed to the two beams 18, 20 on which it rests, by means of two lugs 46 extending in the plane of the horizontal slice 38. The two lugs 46 receive respectively a vertical fixing member 48 passing through the corresponding beam.

[0048] It will be noted that these fastening elements 48 can advantageously also allow the fastening of the front lower suspension arms of the motor vehicle.

[0049] Furthermore, the additional U-shaped cross member 28 has a central portion 50 on which two rear U-shaped profiles 52, 54 are mounted back to back, symmetrical to each other with respect to the median plane Pm. The two rear U-shaped profiles 52, 54 are welded to the bottom portion 34 of the cross member 28 and thus form a bracket 55 into which a rear silent block 56 is engaged along a horizontal transverse axis.

[0050] The rear silent block 56 allows the anchoring of an electric powertrain 58. It also allows the filtering of high-frequency vibrations of the powertrain.

[0051] In this way, thanks to the additional U-shaped cross member 28, we bring together, on the one hand, an anchoring point for the powertrain 58 via the clevis 55 and the rear silent block 56, and on the other hand, two body supports which we will now detail with reference to [Fig.2] and [Fig.3].

[0052] It will be observed that the first front crossmember 22 has another bracket 57, located towards the front, which accommodates a front silent block 59 allowing the propulsion engine group to also be anchored.

[0053] We find on [Fig.2] the vertex 44 of the left branch 32.

[0054] Also, we find partially the vertical slice 40 converging towards the inclined slice 42. They end with two horizontal and parallel portions which connect together the rear flank and the front flank by forming a vertical seat 60 of hemicylindrical symmetry.

[0055] A first socket 62 can then be fitted into this vertical seat 60 and welded to it along the edges of the seat 60 and along two opposite generatrices of the socket 62. Thus two first diametrically opposed weld beads, of which only one 64 appears on the [Fig.2], can be provided.

[0056] On [Fig.2], and according to a first embodiment variant, the first weld beads 64, made at the joint between the edges of the seat 60 and the sleeve 62, are of small length J, corresponding substantially to half the length of the sleeve 62.

[0057] Also, the socket 62 receives a screwable fixing element 66 allowing the body of the motor vehicle not shown to be anchored to it.

[0058] Thus, it is understood that the body of the motor vehicle is connected to the top 44 of the left branch 32 by means of the socket 62. And the latter is connected to the top 44 by the first weld beads 64 only.

[0059] Naturally, the vertex 44 of the right branch 30 has the same configuration as that described above at the right of [Fig.2]

[0060] Therefore, during an impact, the first weld beads 64 may break and the body may detach from the tips 44 of the branches 30, 32 by absorbing kinetic energy related to the impact.

[0061] According to a second embodiment of the invention as illustrated in [Fig.3], where the elements identical to those of [Fig.2] bear the same reference number affected by a prime sign "'", the second weld beads 64', made at the joint between the edges of the seat 60' and the sleeve 62', are of great length L, corresponding substantially to the length of the sleeve 62'.

[0062] Also, the socket 62' receives a screwable fixing element 66' to anchor the body of the motor vehicle.

[0063] Thus, the body of the motor vehicle is more firmly connected to the top 44' of the left branch 32' compared to the first aforementioned implementation variant.

[0064] Consequently, the intensity of the shock will have to be greater to cause the rupture of the second weld beads 64'.

[0065] Thus, it is understood that the resistance to breakage of the bond between the apex 44, 44' of the branches 32, 32', can be modulated by modifying the length of the weld beads 64, 64'.

[0066] In this way, it is possible on the same manufacturing platform to produce significantly different models, in terms of mass distribution for example, by adjusting the length of the aforementioned weld beads according to the model.

Claims

Demands

1. Front cradle of an electric motor vehicle comprising: - a rear cross member (12) adapted to be installed transversely in the extension of a motor vehicle chassis, said rear cross member having two opposite lateral ends (14, 16); - two beams (18, 20) connected respectively to said two lateral ends (14, 16), said two beams extending along a horizontal component perpendicular to said rear cross member (12) and opposite said chassis; - two body supports (30, 32) erected respectively on said two beams (18, 20) in the vicinity of said rear cross member; characterized in that it comprises a complementary U-shaped cross member (28) having two opposite arms (30, 32) forming respectively said two body supports, said complementary U-shaped cross member resting on said two beams (18, 20) parallel to said rear cross member (12).

2. Front cradle according to claim 1, characterized in that said additional U-shaped cross member (28) includes a clevis (55) located substantially equidistant from said two arms (30, 32) to be able to anchor the motor vehicle's powertrain.

3. Front cradle according to claim 2, characterized in that said clevis (55) receives a silent block (56) to filter vibrations between said powertrain (58) and said U-shaped supplementary cross member (28).

4. Front cradle according to claim 2 or 3, characterized in that said clevis (55) comprises two U-shaped profiles (52, 54) back to back, extending opposite each other erected on said complementary U-shaped cross member (28).

5. Front cradle according to any one of claims 1 to 4, characterized in that said U-shaped supplementary cross member (28) is hollow.

6. Front cradle according to any one of claims 1 to 5, characterized in that said complementary U-shaped cross member (28) is made by folding and stamping a metal plate.

7. Front cradle according to any one of claims 1 to 6, characterized in that said two arms (32, 34) of said complementary U-shaped cross member (28) have a triangular shape.

8. Front cradle according to any one of claims 1 to 7, characterized in that each of the apexes (44) of said arms (30, 32) has a seat (60) for receiving an anchor sleeve (62) oriented along a component perpendicular to said rear cross member (12) and to said beams (18, 20), and in that said anchor sleeve (62) is connected to the apex of said arm by welding.

9. Front cradle according to claim 8, characterized in that said anchor sleeve (62) is connected to the top of said arm by at least two weld beads (64) of a predetermined length along two opposite generatrices of said anchor sleeve.

10. Front cradle according to any one of claims 1 to 9, characterized in that it further comprises a front cross member (22) connecting together said beams (18, 20), at a distance and substantially parallel to said rear cross member (12).

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