Rear rigid axle of a motor vehicle

Abstract

The invention relates to a rear rigid axle (10) of a motor vehicle, comprising: a rectangular tubular crossmember (12) having an upper face (18) opposite a lower face (20), and two ends (14, 16) opposite one another; two hubs (26, 28) respectively mounted on said two opposite ends (14, 16) of said rectangular tubular crossmember (12) so as to be able to each receive a wheel. And, said tubular crossmember (12) has a longitudinal rib formed in at least one (20) of said upper and lower faces. Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Rear rigid axle of a motor vehicle

[0001] the present invention relates to a rear rigid axle of a motor vehicle.

[0002] One envisaged field of application is in particular that of light vehicles.

[0003] Known rear rigid axles comprise a cross member connecting two hubs, each of which supports a wheel. Such axles are usually referred to as rigid, because they designate relatively simple axles, by virtue of their construction, and which can withstand more or less heavy loads.

[0004] The crosspiece is tubular and rectangular in section. It has an upper face opposite a lower face and two opposite ends on which the hubs are respectively mounted.

[0005] Usually, the crosspiece is connected to “spring” blades by means of stirrups, which extend longitudinally near the hubs.

[0006] The ends of the “spring” blades are then connected to the body of the vehicle.

[0007] In addition, the crossmember can be equipped with two coil springs provided with a shock absorber, and installed on its upper face. The coil springs thus come to bear against the body of the vehicle.

[0008] In addition, generally, two hydraulic shock absorbers connect the cross member to the body.

[0009] Also, in this type of vehicle, the track, that is the distance which separates the two wheels from the axle, is relatively important, compared to that of passenger vehicles. And it needs to be increased in certain circumstances.

[0010] Therefore, the stresses exerted on the tubular crosspiece increase and it is necessary to add reinforcement to them. For example, it is known to weld a flat at least on one of the faces of the tubular crosspiece, and over its entire length, to increase the resistance to bending.

[0011] Such a reinforcing flat makes the crosspiece heavier.

[0012] Also, a problem which arises and which the present invention aims to solve is to provide a rigid axle, the bending resistance of which is increased without being heavier.

[0013] In order to solve this problem, a rigid rear axle for a motor vehicle is proposed, comprising: a rectangular tubular crossmember having an upper face opposite a lower face, and two ends opposite each other; two hubs respectively mounted on said two opposite ends of said rectangular tubular crossmember so as to each be able to receive a wheel.

[0014] Also, said tubular crosspiece has a longitudinal rib formed in at least one of said upper and lower faces.

[0015] Thus, a characteristic of the invention lies in the implementation of a longitudinal rib, on at least one of the faces of the cross member to be able to increase the resistance of the axle to bending, without adding material to it. In this way, the weight of the axle is generally unchanged, and its mechanical resistance to bending is increased.

[0016] It will also be observed that such a longitudinal rib can be easily implemented on the rectangular tubular sleepers traditionally used in this application to axles. And consequently, there is no need to provide sleepers with a larger section or a greater metal thickness.

[0017] According to a particularly advantageous characteristic of the invention, said longitudinal rib extends from one to the other of said two opposite ends. In this way, the resistance to bending deformation of the axle is increased over its entire length.

[0018] Preferably, and according to the invention, said longitudinal rib extends projecting inside said rectangular tubular crossmember. In this way, the rectangular tubular crossmember does not have any protrusion projecting outwards. And consequently, it does not extend beyond the space defined by an equivalent rectangular tubular crossmember without a rib. In other words, there is no need to use excess material which would increase the overall volume of the crossmember.

[0019] Also, preferably, according to the invention, said longitudinal rib is provided in said lower face. The lower face of the crossmember does not interact with any element of the axle and consequently, the rib does not interfere in any way with the connections with the hubs, the stirrups allowing the “spring” blades to be fixed. The rib also does not interfere with the installation of the coil springs.

[0020] In addition, said longitudinal rib is preferably provided according to the invention, if by local depression of a longitudinal median zone of said one of said upper and lower faces, towards the inside of said crosspiece.

[0021] Thus, such a longitudinal rib is easy to produce when profiling the crosspiece using a roller for example.

[0022] Also, according to a particular embodiment of the invention, said longitudinal median zone has a width of between one third and two thirds of the width of said one of said upper and lower faces. For example, the longitudinal median zone has a width close to half the width of said one of said upper and lower faces.

[0023] Preferably, said tubular crossmember is obtained, according to the invention, by forming a metal strip having two opposite edges, said two edges being folded back towards the inside of said crossmember to be welded back to back and form said longitudinal rib. In this way, the rib is easily obtained, starting from a metal strip, and folding it along four longitudinal lines and by bending the two opposite free edges to weld them back to back, as will be explained in more detail later in the description.

[0024] According to another object, and according to the invention, there is provided a motor vehicle comprising a rear rigid axle as described above.

[0025] Other features and advantages of the invention will emerge from 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:

[0026] [Fig-1] is a schematic perspective view from above of a rear rigid axle according to the invention;

[0027] [Fig.2] is a schematic perspective view from below of an element of the object of [Fig.l];

[0028] [Fig.3] is a schematic cross-sectional detail view of the object of [Fig.2] according to plan III - III;

[0029] [Fig.4] is a schematic view of a straight section according to another method of rea lization of the object of [Fig.2].

[0030] [Fig.l] shows a rear axle 10 of a light motor vehicle, for example of the camper van type.

[0031] The axle 10 is inscribed in an orthogonal reference frame X, Y, Z, in which the X axis extends in a front-rear longitudinal direction of the motor vehicle, 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.

[0032] The axle 10 comprises a tubular cross member of rectangular section 12, which has a right end 14 opposite a left end 16.

[0033] The tubular crosspiece 12 has an upper face 18 opposite a lower face 20 and a front face 22 opposite a rear face 24.

[0034] Also, the right front end 14 of the cross member 12 is equipped with a right hub 26, and the left end 16 is equipped with a left hub 28. The hubs, right 26 and left 28 respectively receive the two rear wheels, which are not shown here.

[0035] The tubular crosspiece 12 receives two spring blades perpendicularly, a right spring blade 30 which extends on its upper face 18 at the right end 14 and a parallel left spring blade 32, extended on its upper face 18 at the left end 16. These two spring blades 30, 32 are made integral with the tubular crosspiece 12, respectively, by means of two pairs of stirrups 34, 36.

[0036] Each of the two spring blades 30, 32 comprises a front fixing end 38 and a rear fixing end 40 adapted to be mounted articulated under the body of the vehicle. The latter is not shown here.

[0037] In addition, the tubular crossmember 12 is equipped with two helical springs, a right spring 42 and a left spring 44, which extend vertically on the upper face 18, and respectively near the right spring blade 30 and the left spring blade 32. Each of the helical springs 42, 44 is provided inside with a shock stop. Also, they come to bear under the body of the vehicle.

[0038] And in addition, two hydraulic shock absorbers, a right shock absorber 46 and a left shock absorber 48 connect obliquely towards the rear, the tubular cross member 12 and the body of the vehicle.

[0039] In [Fig.2], we see in more detail the tubular crosspiece 12 seen from below. And thus, in this [Fig.2], the lower face 20 and the rear face 24 of the tubular crosspiece 12 appear.

[0040] Also appearing are the two opposite ends 14, 16 respectively equipped with the hubs 26, 28.

[0041] Also, it will be observed that the lower face 20 has a longitudinal groove 50, extending from the right end 14 to the left end 16 of the tubular crosspiece 12.

[0042] This longitudinal groove 50 has a depth of substantially between two and three times the thickness of the wall of the crosspiece. It thus forms, in the lower face 20 of the tubular crosspiece 12, a rib 52 which can be seen in more detail in [Fig. 3].

[0043] The longitudinal groove 50 is for example produced continuously by means of a roller applied by force locally in a middle zone of the lower face 20.

[0044] In this [Fig.3] we find the tubular crosspiece 12 in cross section. Also appearing are its upper face 18 opposite its lower face 20 and its front face 22 opposite its rear face 24.

[0045] Also, it will be observed that the tubular crosspiece 12 results from the folding of a metal strip where the two opposite longitudinal edges are welded against each other to close the crosspiece and form a uniform wall. The uniform wall thus defines an interior 53 opposite the exterior 55.

[0046] The tubular crosspiece 12 is of rectangular section, and it has a width L greater than a height H, while its four corners are rounded. For example, the width L of the crosspiece is equivalent to four thirds of its height H.

[0047] Also, the tubular crosspiece 12 is advantageously made of steel and the thickness of its wall is for example between 1.2 mm and 3.2 mm.

[0048] Furthermore, it will be observed that in the example presented here, in [Fig.3], the width of the groove 50 is between half and two-thirds of the width L.

[0049] In this way, thanks to the rib 52, counterpart of the groove 50, the quadratic moment of the axle 10 is significantly increased in comparison with an axle whose tubular crossmember would not have any rib.

[0050] In other words, the axle 10 offers superior mechanical resistance to bending, without adding material.

[0051] Reference will be made to [Fig.4] showing the section of a tubular crosspiece 12' according to another embodiment.

[0052] The elements of the crosspiece 12' similar to those of the crosspiece 12 shown in [Fig.3], will have the same reference accompanied by a prime sign: “'”.

[0053] Thus, the tubular crosspiece 12' is also of rectangular section, and its width L' is greater than its height H'.

[0054] It is made of steel and its wall thickness is between 1.2 mm and 3.2 mm.

[0055] On the other hand, while the tubular crosspiece 12 illustrated in [Fig. 3] results from the folding of a metal strip where the two opposite edges are welded against each other, the tubular crosspiece 12' illustrated in [Fig. 4] is obtained by bending the two opposite edges 56, 58 in return, in order to be able to weld them back to back so that they extend projecting towards the inside of the crosspiece 12'.

[0056] In this way, a rib 52' is obtained, which also increases the quadratic moment of the axle 10 in comparison with an axle whose tubular crossmember does not have any rib.

[0057] We also find the upper face 18' of the tubular crosspiece 12' opposite the lower face 20', and the front face 22' opposite the rear face 24'.

[0058] And the resulting axle also offers superior mechanical resistance to bending and without adding material.

[0059] According to an alternative embodiment of the invention not shown, the tubular crosspiece has two longitudinal ribs provided respectively in two separate faces. For example, one longitudinal rib is provided in the upper face, while another is provided in the lower face.

[0060] Also, the number of ribs is in no way limiting. And, ribs can be provided in the front and rear faces of the tubular crossmember.

Claims

Claims

1. Rear rigid axle (10) of a motor vehicle, comprising: - a rectangular tubular crossmember (12) having an upper face (18) opposite a lower face (20), and two ends (14, 16) opposite one another; - two hubs (26, 28) respectively mounted on said two opposite ends (14, 16) of said rectangular tubular crossmember (12) so as to each be able to receive a wheel; characterized in that said tubular crossmember (12) has a longitudinal rib (52) formed in at least one (20) of said upper and lower faces.

2. Rear rigid axle according to claim 1, characterized in that said longitudinal rib (52) extends from one (14) to the other (16) of said two opposite ends.

3. Rear rigid axle according to claim 1 or 2, characterized in that said longitudinal rib (52) extends projecting inside (53) said rectangular tubular crossmember (12).

4. Rear rigid axle according to any one of claims 1 to 3, characterized in that said longitudinal rib (52) is formed in said lower face (20).

5. Rear rigid axle according to any one of claims 1 to 4, characterized in that said longitudinal rib (52) is formed by local depression of a longitudinal median zone of said one (20) of said upper and lower faces, towards the inside (53) of said crossmember (12).

6. Rear rigid axle according to claim 5, characterized in that said longitudinal median zone has a width between one third and two thirds of the width of said one (20) of said upper and lower faces.

7. Rear rigid axle according to any one of claims 1 to 4, characterized in that said tubular crossmember (12) is obtained by forming a metal strip having two opposite edges (56, 58), said two edges being folded back towards the inside (53') of said crossmember (12) to be welded back to back and form said longitudinal rib (52').

8. A motor vehicle comprising a rear rigid axle (10) according to any one of claims 1 to 7.

Images