Reinforced torsional rear axle

Abstract

The invention relates to a rear axle comprising: - a pair of suspension arms, each having an intermediate zone; - a cross member (16') connecting the intermediate zones, said arms forming two angles (40, 42) with said cross member (16); - two cups (44') mounted in said two angles and each having, on the one hand, an upper face (65') having a central part (72') and on the other hand, a distal transverse part (82') having an edge (48'); Each of said cups includes a proximal transverse part (88') extending between said distal transverse part (82') and said central part (72'); and said proximal part (88') is bent in one direction relative to said central part, while said distal transverse part (82') is bent in the opposite direction, so as to be able to further weld said distal transverse part to the junction between said distal transverse part and said proximal transverse part.Figure to be published with the abbreviation: Fig. 3.

Description

Title of the invention: Reinforced torsional rear axle

[0001] The present invention relates to a torsional rear axle of a motor vehicle.

[0002] These torsionally flexible rear axles, also called "flexible" axles, usually comprise a pair of suspension arms connected to each other by a cross member. The suspension arms have a front end pivotally mounted on the underside of the chassis, and at the opposite end, a rear end receiving a wheel support to accommodate a wheel.

[0003] The crossmember connects the two suspension arms in a T-shape at an intermediate point between their front and rear ends. Each arm has a rear portion extending from this intermediate point to its rear end, forming two rear angles with the crossmember. Two support cups are mounted at these rear angles to receive two coil springs installed vertically. Each cup has a top face to receive the spring. Furthermore, each cup has a front edge welded to the crossmember and a side edge welded to the rear portion of the corresponding arm.

[0004] The cups not only allow the helical springs to be supported, but also help to keep the arms and the cross member in a fixed position in substantially perpendicular directions.

[0005] Such torsional rear axles are compact and relatively lightweight. Therefore, they are commonly installed on various motor vehicles, both commercial and non-commercial, and generally entry-level models.

[0006] Furthermore, these different motor vehicles are manufactured on a common platform with components having geometries specific to each vehicle. Nevertheless, efforts are made to reduce, as much as possible, the number of parts specific to the different types of vehicles.

[0007] However, the axle elements of some vehicles are more or less stressed compared to the axle elements of other vehicles made on the same platform.

[0008] In particular, the forces exerted on the suspension arms and on the cross member can locally stress the cross member via the cups.

[0009] Also, a problem which arises and which the present invention aims to solve is to provide a torsible rear axle which can be obtained on the same platform in different possible architectures, without compromising the fatigue resistance of certain areas for certain architectures.

[0010] In order to solve this problem, and according to a first object, a rear axle for a motor vehicle is proposed comprising:

[0011] - a pair of suspension arms, each of the suspension arms having a front end and rear end opposite each other with respect to an intermediate zone;

[0012] - a cross member connecting in a T-shape the intermediate zones of the suspension arms, said arms, each having a rear portion extending from said intermediate zone to said rear extremity and forming two angles with said cross member; and,

[0013] - two support cups mounted respectively in said two angles, each said cups comprising, on the one hand, an upper face having a central part suitable for receiving a spring and on the other hand, a distal transverse part having an edge connected to said crossbar.

[0014] Each of said cups includes a proximal transverse part extending between said distal transverse part and said central part, and said proximal transverse part is bent in one direction relative to said central part, while said distal transverse part is bent in the opposite direction relative to said proximal transverse part, in order to apply said distal transverse part against said cross member and to further weld said distal transverse part to said cross member at the junction between said distal transverse part and said proximal transverse part.

[0015] Thus, a feature of the invention lies in the implementation of cups that allow them not only to be welded to the cross member along the edge of the distal transverse portion, but also to be welded at the junction between the distal transverse portion and the proximal transverse portion. In other words, two weld beads are formed: one between the edge of the distal portion and the cross member, and the other between the distal portion and the cross member under the proximal portion. The two weld beads are then substantially parallel. And they allow for a more rigid connection between the cup and the cross member. This, in turn, improves the fatigue resistance of the junction between the cup and the cross member.

[0016] According to a particularly advantageous embodiment of the invention, said distal transverse portion has a slot for welding said distal transverse portion to said cross member through said slot. The slot formed in the distal transverse portion allows for the creation of two opposing edges that meet the cross member. In this way, at least one other weld bead can be applied between one of the two edges and the cross member. This embodiment further stiffens the connection between the cup and the cross member.

[0017] Preferably, said light extends transversely substantially parallel to said edge. It is thus possible to produce a weld bead substantially parallel to that which is formed along the edge of the distal part.

[0018] According to the invention, said distal transverse portion is advantageously substantially flat. The cross member itself has substantially flat sides onto which the distal transverse portions are flatly applied. Consequently, the supports of the cups on the cross member are more stable, and thanks to the weld beads, the rigidity of the connection between the cups and the cross member is further improved.

[0019] Also, according to the invention, said proximal transverse portion is preferentially folded in the opposite direction to said central portion of said upper face. In other words, the proximal transverse portion is folded towards the lower face of the cup, opposite the upper face. And the distal transverse portion, which extends from the proximal portion, is then folded in the opposite direction. Thus, it is the lower face of the distal transverse portion that is applied against the crossbar.

[0020] Furthermore, said distal transverse portion forms an angle of less than 120° with said proximal transverse portion. This angle is, for example, 110°. Thus, as will be explained in more detail later in the description, such an angle provides sufficient space between the distal proximal portion and the cross member to allow the head of a welding torch to engage. The distal transverse portion can then be more easily welded to said cross member at the junction with the proximal transverse portion.

[0021] According to one embodiment of the invention, said distal transverse portion has a border running along said edge, and said border comprises a first transverse portion, opposite said edge, folded towards said proximal transverse portion, and a second portion running along said edge, folded in the opposite direction. In other words, the border forms with the cross member a tubular part that stiffens the assembly.

[0022] According to a particularly advantageous embodiment of the invention, said border is folded into a V.

[0023] In addition, each of said cups preferably has a longitudinal distal part substantially perpendicular to said transverse distal part, said longitudinal distal part being connected to said arm.

[0024] 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:

[0025] [Fig.1] is a schematic top perspective view of the object of the invention according to the prior art;

[0026] [Fig.2] is a schematic view of the object of [Fig.1] in section along plane II-II;

[0027] [Fig.3] is a schematic cross-sectional view of the object of the invention according to a first variant of execution; and,

[0028] [Fig.4] is a schematic cross-sectional view of the object of the invention according to a second embodiment.

[0029] Fig. 1 shows, viewed from above, a rear axle of a motor vehicle 10.

[0030] 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 a driving situation; and the Z axis extends along a vertical direction, oriented away from the ground.

[0031] Also, the rear axle 10 includes a pair of suspension arms, a left arm 12 opposed to a right arm 14 with respect to the median plane Pm. Both suspension arms 12, 14 are tubular.

[0032] In addition, the two suspension arms 12, 14 are connected together by a tubular cross member 16.

[0033] The left suspension arm 12 has a left front end 18 opposite a left rear end 20, while the right suspension arm 14 has a right front end 22 opposite a right rear end 24.

[0034] The front ends 18, 22 of the two arms 12, 14 are equipped with a transversely extending bushing 26. The bushings 26 connect the two ends 18, 22 of the arms to the underside of the chassis of a motor vehicle. The two arms 12, 14 are pivotally mounted on the chassis at the rear of the vehicle by means of rubber bushings. The rubber bushings are engaged through the bushings 26 and they dampen vibrations from the arms.

[0035] On the opposite side, the rear ends 20, 24 of the two arms 12, 14 are equipped with wheel supports 28.

[0036] Also, the cross member 16 has two opposite ends, a left end 30 and a right end 32. And the two ends 30, 32 are notched in a "wolf's mouth" to form two seats adapted to receive respectively the two arms 12, 14. Thus, the two ends 30, 32 receive respectively an intermediate zone 34 of the two arms 12, 14, located approximately at two-thirds of the distance which extends from the rear ends 20, 24 to the corresponding front ends 18, 22.

[0037] Also, the arms 12, 14 are connected in T to the cross member 16 by means of weld beads applied to the joints between the two ends 30, 30 of the cross member 16 and respectively the intermediate areas 34 of the two arms 12, 14.

[0038] Thus, the intermediate zone 34 delimits, for the left arm 12 a rear left portion 36 extending from the intermediate zone 34 to the rear left end 20 and for the right arm 14, a rear right portion 38 extending from the intermediate zone 34 to the rear right end 24.

[0039] The rear left portion 36 and the rear right portion 38 form respectively with the cross member 16 a rear left angle 40 and a rear right angle 42.

[0040] The axle 10 includes a left-hand cup 44 installed in the left rear corner 40 and a right-hand cup 46 installed in the right rear corner 42. The cups 44, 46 are obtained by a stamping and deep-drawing process on a metal plate, as will be explained in more detail below. The metal plate has, for example, a thickness of between 1 mm and 3 mm. According to a particularly advantageous embodiment of the invention, the metal plate has a thickness of 2 mm.

[0041] The left cup 44 has a left front edge 48 welded to the cross member 16 and a left lateral edge 50 welded to the left rear portion 36 of the left arm 12. And oppositely, the right cup 46 has a right front edge 52 welded to the cross member 16 and a right lateral edge 54 welded to the right rear portion 38. The cups 44, 46 extend substantially in the mean plane defined by the cross member 16 and the two suspension arms 12, 14.

[0042] Also, the left cup 44 has a free left lateral rim 56 opposite the left lateral rim 50 and a free left rear rim 58 opposite the left front rim 48. The two free rims 56, 58 are substantially perpendicular to each other and they meet to form a left arc 60. The left cup 44 also has a left upper face 65 opposite a left lower face 67.

[0043] Also, it will be observed that the free edges 56, 58 are upright relative to the lower left face 67. In this way, these upright free edges 56, 58 make it possible to increase the rigidity of the cup 44.

[0044] In contrast, the right cup 46 has a free right lateral edge 62 opposite the right lateral edge 54 and a free rear right edge 64 opposite the front right edge 52. The two free edges 62, 64 are substantially perpendicular and they meet to form a right circular arc 66. The right cup 46 has a straight upper face 68 opposite a straight lower face 70.

[0045] Similarly, the two free edges 62, 64 are raised relative to the lower right face 70 to increase the rigidity of the right cup 46.

[0046] The cups, left 44 and right 46, allow, on the one hand, to keep the cross member 16 and the two arms, left 12, right 14, square, and on the other hand to receive helical springs, not shown, in support on the upper face 65, 68.

[0047] Also, the upper faces 65, 68 of the cups 44, 46 each have a central portion 72 deformed into a dome that projects from said upper surface. In this way, the bases of the springs bear axially against the upper faces 65, 68, around their central portion 72. Consequently, the base of the springs in contact with the upper faces 65, 68 is prevented from moving in translation along the planes defined respectively by the cups 44, 46.

[0048] Helical springs are axially compressible in a direction substantially perpendicular to the upper faces 65, 68.

[0049] Reference will now be made to [Fig.2] showing in detail and partially the left cup 44 and the cross member 16 seen according to the section II-II identified on [Fig.1].

[0050] The tubular cross member 16 has a convex upper part 74 opposed to a concave lower part 76. Also, it has a rear flank 78 opposed to a front flank 80.

[0051] The left cup 44 is partially represented, showing its upper left face 65 and its central part 72. In addition, the cup 44 has a transverse distal part 82 bearing against the rear side 78 of the cross member 16. The distal part has a border 84 running along the edge 48. And the edge 48 is connected to the cross member 16 by means of a first weld bead 86.

[0052] Also, the cup 44 includes a proximal transverse part 88 which extends between the distal transverse part 82 and the central part 72.

[0053] The right cup 46 is naturally arranged in the same way on the cross member 16 in the right rear corner 42. And this method of arrangement is representative of that of the prior art.

[0054] Also, two embodiment variants of the invention will be described with reference to [Fig.3] and [Fig.4] in which the proximal transverse part of the two cups is bent in one direction relative to the central part, while the distal transverse part is bent in the opposite direction, to apply the distal transverse part against the rear side of the cross member and to be able to weld the distal transverse part onto the cross member at least two different places.

[0055] Also, on [Fig.3] and [Fig.4], the analogous elements of the object of [Fig.2] and presenting the same functions, shall bear the same references respectively affected by the prime signs, « ' » and double prime « ” ».

[0056] According to the first embodiment illustrated in [Fig. 3], the distal transverse portion 82' is flat. And, the proximal transverse portion 88' is folded in the opposite direction to the upper face 65' of the central portion 72', while the distal transverse portion 82' is folded in the opposite direction, forming substantially a V. The distal transverse portion 82' thus lies substantially flat against the rear flank 78'.

[0057] It will be observed that the distal transverse part 82' forms with the proximal transverse part 88' an angle A approximately equal to 90°. Consequently, the proximal transverse part 88' forms with the rear flank 78' an angle B also close to 90°.

[0058] Consequently, it is easy to engage a welding head under the cup 44' to produce a second weld bead 90 on the rear side 78' of the cross member 16', at the junction between the distal transverse part 82' and the proximal transverse part 88'. Such a possibility is still available when angle B is not less than 70°. Consequently, it is available when angle A is less than 110°.

[0059] Also, the edge 48' of the distal transverse portion 82' and the first weld bead 86' which connects it to the cross member 16' are also found. The two weld beads 86' and 90' provide a stronger connection between the distal transverse portion 82' and the cross member 16'.

[0060] Furthermore, the distal transverse portion 82' has a transverse opening 92 which extends substantially parallel to the edge 48' of the distal portion 82' and substantially equidistant between the proximal portion 88' and the edge 48'. Thus, a third, intermediate weld bead 94 is formed within the transverse opening 92 between the rear flank 78' and the distal portion 82'. This further strengthens the connection between the cup 44' and the cross member 16'.

[0061] Also, the right cup, according to this first embodiment, has the same geometry as the left cup 44'. It is therefore attached to the cross member 16' and to the right arm in the same way as the left cup.

[0062] Fig. 4 illustrates a second embodiment of the invention where the 84'' border is folded into a V.

[0063] Thus, the border 84' ' comprises a first transverse portion 96, opposite the edge and folded towards the proximal transverse part 88”, and a second portion 98 along the edge 48” and folded opposite.

[0064] The edge 48” is connected to the cross member 16” by means of the first weld bead 86”. The third weld bead 94” is also located inside the transverse opening 92”. In this way, the V-folded edge 84” forms with the rear side 78” a transverse tubular zone with a substantially triangular cross-section, which locally stiffens the distal transverse part 82” and the rear side 78”.

[0065] The second weld bead 90” is also found on the rear side 78” of the cross member 16”, at the junction between the distal transverse part 82” and the proximal transverse part 88”.

[0066] Furthermore, it will be noted that the 44” cup is obtained at an advantageous cost by stamping / drawing. Also, the implementation of an 84” V-folded rim facilitates the process and the extraction of the cup after stamping.

[0067] Naturally, the right cup, according to this second embodiment, has the same geometry as the left cup 44”.

Claims

Demands

1. Rear axle of a motor vehicle comprising: - a pair of suspension arms (12, 14), each of the suspension arms having a front end and a rear end opposed to each other with respect to an intermediate zone (34); - a cross member (16) connecting in a T-shape the intermediate zones (34) of the suspension arms (12, 14), said arms each having a rear portion extending from said intermediate zone to said rear end and forming two angles (40, 42) with said cross member (16); - two support cups (44, 46) mounted respectively in said two angles (40, 42), each of said cups having, on the one hand, an upper face (65, 68) having a central portion (72) adapted to receive a spring and, on the other hand, a distal transverse portion (82) having an edge (48) connected to said cross member (16);characterized in that each of said cups comprises a proximal transverse part (88) extending between said distal transverse part (82) and said central part (72); and in that said proximal transverse part (88) is bent in one direction relative to said central part, while said distal transverse part (82) is bent in the opposite direction relative to said proximal transverse part, in order to apply said distal transverse part (82) against said cross member (16) and to further weld said distal transverse part to said cross member at the junction between said distal transverse part and said proximal transverse part.

2. Rear axle according to claim 1, characterized in that said distal transverse part has a light (92) for welding said distal transverse part (82) to said cross member (16) through said light.

3. Rear axle according to claim 2, characterized in that said light (92) extends transversely substantially parallel to said edge (48').

4. Rear axle according to any one of claims 1 to 3, characterized in that said distal transverse part (82) is substantially flat.

5. Rear axle according to any one of claims 1 to 4, characterized in that said proximal transverse portion (88') is folded in the opposite direction to said central part (72') of said upper face.

6. Rear axle according to any one of claims 1 to 5, characterized in that said distal transverse part (82') forms an angle of less than 120° with said proximal transverse part (88').

7. Rear axle according to any one of claims 1 to 6, characterized in that said distal transverse part (82”) has a border (84”) along said edge (48”), and in that said border comprises a first transverse portion (96), opposite said edge, folded towards said proximal transverse part (88”) and a second portion (98) along said edge, folded opposite.

8. Rear axle according to claim 7, characterized in that said edge (84”) is folded in a V.

9. Rear axle according to any one of claims 1 to 8, characterized in that each of said cups has a longitudinal distal portion substantially perpendicular to said transverse distal portion, said longitudinal distal portion being connected to said arm.

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