Twistable rear axle

Abstract

The present invention relates to a motor vehicle axle (10'). It comprises: two suspension arms (12') each having a front end and a rear end; a crossmember (16') connecting the suspension arms in a T-shape in an intermediate zone, said two arms each having a rear portion forming two rear angles with said crossmember (16'); two support cups (44') having, on the one hand, an upper face (65') for receiving a spring in support, and on the other hand, a front edge (48') welded to said crossmember and a lateral edge (50') welded to said rear portion. Said front edge (48') of said two cups (44') has an application surface (74') against said crossmember, greater than the section of said two cups (44') along a plane Pp' extending perpendicular to said upper face (65') and along said front edge (48'). Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Torsional rear axle

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

[0002] These twistable rear 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 chassis on the underside, and on the opposite side, a rear end receiving a wheel support to accommodate a wheel.

[0003] The cross member connects the two suspension arms in a T-shape in an intermediate zone located between their front end and their rear end. Thus, the two arms each have a rear portion extending from the intermediate zone to the rear end, forming two rear angles with the cross member. And two support cups are mounted respectively in the two rear angles to receive two coil springs installed along a vertical component. Each of the cups has an upper face to be able to receive the spring in support. In addition, they each have a front edge welded to the cross member and a lateral edge welded to the rear portion of the corresponding arm.

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

[0005] Such twistable rear axles are compact and relatively light. They are therefore commonly installed on various commercial and non-commercial motor vehicles, and generally entry-level.

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

[0007] However, the axle elements of certain 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 twistable rear axle which can be obtained on the same platform in different possible architectures, without compromising the fatigue resistance of certain zones for certain architectures.

[0010] In order to solve this problem, and according to a first object, a rear axle of a motor vehicle is proposed comprising: a pair of suspension arms, each of the suspension arms having a front end adapted to be pivotally mounted on a vehicle chassis and a rear end receiving a wheel support; a cross member connecting the suspension arms in a T-shape in an intermediate zone located between said front end and said rear end, said two arms each having a rear portion extending from said intermediate zone to said rear end and forming two rear angles with said cross member; and two support cups mounted respectively in said two rear angles, each of said cups having, on the one hand, an upper face to be able to receive a supporting spring, and on the other hand, a front edge welded to said cross member and a lateral edge welded to said rear portion.

[0011] And, said front edge of said two cups has an application surface against said crosspiece, greater than the section of said two cups along a plane extending perpendicular to said upper face and along said front edge.

[0012] Thus, a characteristic of the invention lies in the implementation of a cup whose application surface on the cross-member is greater than the cross-section of the cup, taken behind the front edge. In this way, the contact surface between the cup and the cross-member is increased and consequently, the stresses that the cups exert on the cross-member are reduced, per unit of surface. Consequently, the fatigue resistance of the cross-member is preserved locally.

[0013] According to a first variant embodiment, said front edge has a lateral extension, so that said front edge has a length greater than the length of said cross section. In other words, the cup has a local widening at its edge in connection with the crosspiece. In this way, the length of the connection between the front edge and the crosspiece is increased.

[0014] The cups are connected to the crossmember by means of a weld joint applied between the front edge and the crossmember.

[0015] According to this first variant embodiment, said front edge extends opposite said lateral edge. In other words, the edge comes to bear against the crosspiece opposite the contiguous arm.

[0016] According to a second variant embodiment, said edge is curved opposite said upper face along generatrices parallel to said plane to match the surface of said crossmember. Thus, the curvature of the edge is made so as to be able to cooperate with the surface of the crossmember and ensure a larger contact surface. In addition, a weld bead is also applied to the joint between the edge and the crossmember to bond them together. In this way, the stresses exerted by the front edge of the cup on the crossmember are established over a larger surface and thus do not locally damage the crossmember.

[0017] The application surface of the edge on the crosspiece is to be compared to the application surface that the front edge of the cup would have if it corresponded to the edge of the cup, without its lateral extension corresponding to the first variant of execution.

[0018] Furthermore, according to the invention, each of said cups has a free rear edge opposite said front edge and a free lateral edge opposite said welded lateral edge, and said free edges join together to form an arc of a circle. In this way, the size of the cups is reduced without reducing their resistance to deformation or their performance in holding the arms and the crosspiece together.

[0019] Furthermore, in accordance with the invention, said free edges of each of said cups are preferably curved away from said upper face. In other words, the cups have a fallen edge. In this way, the edge of the cup is stiffened and thereby its resistance to deformation is increased.

[0020] Furthermore, according to the invention, said crosspiece is tubular. The two ends of the tubular crosspiece are then notched so as to form a "wolf's mouth" to receive the arms. The arms and the ends of the crosspiece are then connected together by means of weld beads provided at the joint between the arms and the ends.

[0021] Advantageously, and according to the invention, each of said cups has a deformation of circular symmetry extending in projection from said upper surface. Thus, the end of the helical springs then comes to bear flat on the upper face of the cup around the circular deformation. Thus, the end of the helical springs is held in a fixed position relative to the cups along their mean plane.

[0022] Also, according to another object, the invention relates to a motor vehicle comprising a twistable rear axle, as described above.

[0023] Other features and advantages of the invention will become apparent upon reading the description given below of particular embodiments of the invention, given for informational but non-limiting purposes, with reference to the appended drawings in which:

[0024] [Fig.l] is a schematic perspective view from above of a rear axle of a motor vehicle in accordance with the prior art;

[0025] [Fig.2] is a partial schematic perspective view from above of a rear axle in accordance with the invention and according to a first variant embodiment;

[0026] [Fig.3] is a schematic detail view of the object of [Fig.2]; and,

[0027] [Fig.4] is a schematic perspective detail view of an element of the invention similar to that of [Fig.3] according to a second variant of execution.

[0028] [Fig.l] shows, seen from above, a rear axle 10 of a motor vehicle according to the prior art. And [Fig.2] to [Fig.4] show the modifications made to this rear axle 10 which is the subject of the invention according to two variant embodiments.

[0029] The rear axle 10 is inscribed in an orthogonal reference frame X, Y, Z, of the motor vehicle, in which the X axis extends in a front-rear longitudinal direction, oriented towards the rear; the Y axis extends in a transverse direction of the vehicle, oriented from left to right when in a rolling situation; and the Z axis extends in a vertical direction, oriented away from the ground. Also, the two suspension arms 12, 14 are tubular

[0030] The rear axle 10 comprises a left suspension arm 12 and an opposite right suspension arm 14. The two suspension arms 12, 14 are symmetrical to each other with respect to a median plane Pm.

[0031] Furthermore, the two suspension arms 12, 14 are connected together by a tubular cross member 16.

[0032] 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.

[0033] The front ends 18, 22 of the two arms 12, 14 are equipped with a sleeve 26 extending transversely. The sleeves 26 make it possible to 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 silentblocs. The silentblocs are engaged through the sleeves 26 and they make it possible to filter the vibrations of the arms.

[0034] Conversely, the rear ends 20, 24 of the two arms 12, 14 are equipped with wheel supports 28.

[0035] Also, the crosspiece 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 respectively receive an intermediate zone 34 of the two arms 12, 14, located substantially at two-thirds of the distance which extends from the rear ends 20, 24 to the corresponding front ends 18, 22.

[0036] Also, the arms 12, 14 are connected in a T shape to the crosspiece 16 by means of weld beads applied to the joints between the two ends 30, 30 of the crosspiece 16 and respectively the intermediate zones 34 of the two arms 12, 14.

[0037] Thus, the intermediate zone 34 delimits, for the left arm 12, a left rear portion 36 extending from the intermediate zone 34 to the left rear end 20 and for the right arm 14, a right rear portion 38 extending from the intermediate zone 34 to the right rear end 24.

[0038] The left rear portion 36 and the right rear portion 38 respectively form with crosspiece 16 a left rear angle 40 and a right rear angle 42.

[0039] The axle 10 comprises a left cup 44 installed in the left rear corner 40 and a right cup 46 installed in the right rear corner 42. The cups 44, 46 are obtained by a method of cutting-stamping a metal plate. 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.

[0040] 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 on the other hand, 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.

[0041] Also, the left cup 44 has a free left lateral edge 56 opposite the left lateral edge 50 and a free left rear edge 58 opposite the left front edge 48. The two free edges 56, 58 are substantially perpendicular to each other and they join to form a left arc of a circle 60. The left cup 44 also has a left upper face 65 opposite a left lower face 67.

[0042] Also, it will be observed that the free edges 56, 58 are raised relative to the lower left face 67. In this way, these raised free edges 56, 58 make it possible to increase the rigidity of the cup 44.

[0043] Conversely, the right cup 46 has a free right lateral edge 62 opposite the right lateral edge 54 and a free right rear edge 64 opposite the right front edge 52. The two free edges 62, 64 are substantially perpendicular and they meet to form a right arc of a circle 66. The right cup 46 has a right upper face 68 opposite a right lower face 70.

[0044] In the same way, the two free edges 62, 64 are raised relative to the right lower face 70 to increase the rigidity of the right cup 46.

[0045] The cups, left 44 and right 46, allow, on the one hand, to keep the crosspiece 16 and the two arms, left 12, right 14, at right angles, and on the other hand to receive helical springs, not shown, bearing on the upper face 65, 68. The helical springs are axially compressible in a direction substantially perpendicular to the upper faces 65, 68.

[0046] Furthermore, the cups have a deformation of circular symmetry forming a dome 75 and extending in projection from said upper surface. In this way, the bases of the springs come into axial support against the upper faces 65, 68, around their dome 75. Therefore, the base of the springs in contact with the upper faces 65, 68 is locked in translation along the planes defined respectively by the cups 44, 46.

[0047] We will now refer to [Fig.2] and [Fig.3] showing in detail, according to a first variant of execution, the implementation of a left cup 44' making it possible to preserve the crosspiece 16'. The elements identical to those represented in [Fig.l] and playing the same role will bear the same reference assigned a prime sign: "'".

[0048] We will first refer to [Fig.3] showing only the left cup 44'. However, the right cup, according to this first variant execution, will have the same characteristics.

[0049] Thus, we find the upper face 65' of the cup 44' and the left front edge 48'. Beyond a plane Pp perpendicular to the upper face 65' and extending along the edge 48', the latter has a lateral extension 72 extending opposite the left lateral edge 50'. This lateral extension 72 makes it possible to increase the dimensions of the application surface 74'. The application surface 74' corresponds to the free edge of the edge 48' extended by its lateral extension 72.

[0050] Thus, the application surface 74' has dimensions greater than the section of the cup 44' through the perpendicular plane Pp', which section corresponds substantially to the application surface of the left cup 44 as illustrated in [Fig.l]. The application surface 74' is thus a function of the thickness of the cup and the length of the edge 48' extended by the lateral extension 72.

[0051] Thus, as illustrated in [Fig. 2], the surface area 74' of application against the crosspiece 16' is greater than that of the front edge 48 of the left cup 44 shown in [Fig. 1]. Also, the left front edge 48' is connected to the crosspiece 16' by means of weld beads which extend to the joint between the two.

[0052] In this way, when the axle 10' is stressed and in particular when the left rear portion 36' tends to pivot relative to the cross member 16' by approaching it, the left cup 44' comes to oppose this approach without the application surface 74' coming to punch the cross member 16'. This punching operates in particular in the extension of the free left lateral edge 56', when the front edge 48' is devoid of lateral extension 72.

[0053] Indeed, the increase in the application surface 74' makes it possible to reduce the forces exerted per unit of surface on the crosspiece 16'.

[0054] We will now refer to [Fig.4] showing, according to a second variant embodiment, the increase in the application surface of the cup.

[0055] Elements identical to those shown in [Fig.l] and playing the same role will bear the same reference with a double prime sign: “ ””.

[0056] [Fig.4] shows the only left cup 44” according to this second variant of execution. However, according to this second embodiment the right cup also has the same characteristics.

[0057] Thus, we find the free left lateral edge 56” of the left cup 44”, in front of [Fig.4] and opposite towards the rear, its left lateral edge 50”. We also find its upper face 65” opposite its lower face 67”.

[0058] And we find the front left border 48”, which is curved opposite the upper face according to generators parallel to the plane Pp”.

[0059] Thus, the curved left front edge 48” defines an application surface 74'' which fits the surface of the crosspiece 16”. In this way, a larger application surface is obtained than that obtained according to the prior art.

[0060] The 48” curved left edge is obviously welded onto the 16” crosspiece at the joint between the two.

[0061] Thanks to the dimensions of the 74” application surface of the left cup 44” according to this second variant embodiment, the same advantages are obtained as those obtained thanks to the left cup 44' according to the first variant embodiment. In this way, the 16” crosspiece is prevented from the punching effects of the left cup 44”.

[0062] Furthermore, just as in the first variant embodiment, the right cup, not shown, has the same structural and functional characteristics as the left cup 44”.

Claims

Claims

1. Rear axle (10) of a motor vehicle comprising: - a pair of suspension arms (12, 14), each of the suspension arms having a front end (18, 22) adapted to be pivotally mounted on a vehicle chassis and a rear end (20, 24) receiving a wheel support (28); - a cross member (16) connecting the suspension arms (12, 14) in a T-shape in an intermediate zone (34) located between said front end and said rear end, said two arms (12, 14) each having a rear portion (36, 38) extending from said intermediate zone (34) to said rear end (36, 38) and forming two rear angles (40, 42) with said cross member (16); - two support cups (44, 46) mounted respectively in said two rear corners (40, 42), each of said cups having, on the one hand, an upper face (65, 67;68, 70) to be able to receive a spring in support, and on the other hand a front edge (48, 52) welded to said crosspiece (16) and a lateral edge (50, 54) welded to said rear portion (36, 38); characterized in that said front edge (48, 52) of said two cups (44, 46) has an application surface (74', 74”) against said crosspiece (16), greater than the section of said two cups (44, 46) according to a plane Pp extending perpendicular to said upper face (65, 68) and along said front edge (48, 52).;

2. Rear axle according to claim 1, characterized in that said front edge (48') has a lateral extension (72) so that said front edge (48') has a length greater than the length of said straight section.

3. Rear axle according to claim 2, characterized in that said front edge (48') extends opposite said lateral edge (50').

4. Rear axle according to claim 1, characterized in that said front edge (48”) is curved opposite said upper face (65') according to generatrices parallel to said plane Pp to match the surface of said crossmember (16).

5. Rear axle according to any one of claims 1 to 4, characterized in that each of said cups (44, 46) has a free rear edge (58, 64) opposite said front edge (48, 52) and a free lateral edge (56, 62) opposite said lateral edge (50, 54) welded, and in that said free edges join together to form an arc of a circle (60, 66).

6. Rear axle according to claim 5, characterized in that said free edges (58, 56; 64, 62) of each of said cups (44, 46) are curved away from said upper face (65, 68).

7. Rear axle according to any one of claims 1 to 6, characterized in that said cross member (16) is tubular.

8. Rear axle according to any one of claims 1 to 7, characterized in that each of said cups (44, 46) has a circularly symmetrical deformation (75) extending projecting from said upper surface (65, 68).

9. A motor vehicle comprising a rear axle (10) according to any one of claims 1 to 8.

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