Rear axle for a motor vehicle with two rear trailing arms with improved elastic behavior

Description

[0001] The subject of the invention is a rear axle for a motor vehicle of the type with two longitudinal trailing arms, in particular a rear axle with improved elastic behavior, and in particular with increased understeer induced steering.

[0002] For many years, rear axles for motor vehicles have been known to have two trailing arms, each connected to the vehicle body by two elastic joints, the ends of the trailing arms being opposite those articulated to the body receiving the rear wheels of the vehicle. The wheels of this type of rear axle are therefore independent.

[0003] This type of rear axle is shown figure 1 . Each of the two trailing arms 1, 2 has a stub axle support 3, 4 at its rear end and is connected to the body by two elastic joints with a substantially transverse axis, one 5A, 6A of the elastic joints being located at the front end of the trailing arm 1, 2, the other elastic joint 5B, 6B being located at the front end of an oblique arm 7, 8 secured to the trailing arm 1, 2 respectively, the elastic joints 5B, 6B being located between the joints 5A, 6A transversely. In this type of rear axle, the axes of the joints 5A, 5B on the one hand and 6A, 6B on the other hand, intersect in the median longitudinal and vertical plane (transversely) of the vehicle. These axes may be transverse or form a non-zero angle relative to the transverse direction of the vehicle. Furthermore, the joints 5B, 6B are generally located above the joints 5A, 6A vertically and behind these joints along the longitudinal axis of the vehicle.There . figure 2 represents the behavior of this type of rear axle during a right turn: we see that, under transverse force, the joints 5B, 6B deform elastically, one being shifted forwards and the other backwards in the longitudinal direction, causing oversteer behavior, which is not desirable.

[0004] In order to maintain the joints 5B, 6B longitudinally when taking a turn, a known solution consists of pivoting the arms relative to each other in a transverse direction, in particular using a twistable bar. For this purpose, each front end of a trailing arm is secured to a transverse bar directed towards the front end of the other trailing arm, the transverse bars being mounted pivoting relative to each other around a transverse axis in a transversely middle position. This type of rear axle is nevertheless quite flexible in its center, because the central joint is not connected to the body. Furthermore, for reasons of space, it is difficult to modify this type of structure to achieve significant understeer-induced steering. Document DE 4021157A1 discloses a known vehicle rear axle, in accordance with the preamble of claim 1.

[0005] There is therefore a need for a trailing arm rear axle of the aforementioned type having improved elastic behavior and preferably with understeer-induced steering.

[0006] To this end, the invention relates to a rear axle of a motor vehicle of the type with two longitudinal trailing arms, in which each trailing arm has a spindle support at a rear end, and at an opposite front end, a substantially transverse axis of rotation defined by a first articulation and a second articulation intended to be connected to the body of the vehicle. The second articulations are located between the first articulations transversely and the axes of rotation of the trailing arms intersect at a point of intersection belonging to a median plane (transversely) longitudinal and vertical of the rear axle. According to the invention: one of the trailing arms is secured, on the side of its second articulation, to a first support element extending towards the front of the train, the other trailing arm is secured, on the side of its second articulation, to a second support element extending towards the rear of the train, free ends of the first and second support elements are located in the longitudinal and vertical median plane of the rear train and are connected to each other, and maintained at a fixed distance in a substantially longitudinal direction, by a connecting element mounted to pivot about at least one transverse axis at at least one of the free ends of the first and second support elements.

[0007] This configuration allows longitudinal transmission of the forces experienced by the second joints. In addition, by maintaining the second joints at a fixed distance longitudinally, during a turn, movements of the second joints in opposite directions longitudinally are prevented by the connecting element, improving the guidance of the wheels under transverse force and the elastic behavior of the rear axle.

[0008] The connecting element is pivotally mounted about at least one transverse axis at at least one of the free ends of the first and second support elements or at both free ends, and can be pivotally mounted about at least one other axis, for example about a longitudinal axis and a vertical axis.

[0009] Advantageously, the fixed distance separating the free ends of the first and second support elements can be within an interval from zero to a threshold value. This threshold value can be determined by calculation depending on the desired behavior of the rear axle.

[0010] Advantageously, the connecting element can extend vertically above the point of intersection of the axes of rotation of the trailing arms, in particular at a non-zero distance, less than or equal to a threshold value, typically determined with the vehicle unladen when the rear axle is mounted on the vehicle. This configuration has the advantage of inducing understeer of the rear axle. The threshold value can be determined according to the characteristics of the rear axle and more precisely of the joints.

[0011] The connecting element is preferably a mechanical connecting element, in particular without a hydraulic component, simple to produce.

[0012] In one embodiment, the connecting element may be an elongated part having two ends distant in the longitudinal direction, each of these ends being pivotally mounted at one of the free ends of the first and second support elements around at least one transverse axis of rotation. In this embodiment, the distance between the free ends of the first and second support elements is therefore non-zero. This distance will advantageously be chosen to be as small as possible; the minimum distance may, for example, be imposed by the dimensions of the joints, themselves sized according to the mechanical characteristics of the rear axle and / or be imposed by assembly constraints.

[0013] This elongated part can be in the form of a simple plate, generally flat, typically made of metallic material. The thickness and / or the material may be chosen in particular so that the part withstands the longitudinal forces exerted when the vehicle is moving, particularly when cornering.

[0014] Typically, the elongated part may extend in a horizontal or substantially horizontal plane, parallel or substantially parallel to a horizontal plane containing the point of intersection of the axes of rotation of the trailing arms.

[0015] The ends of the elongated part may be articulated to the free ends of the first and second support elements by joints having at least one transverse axis of rotation. In particular, ball-and-socket joints may be used.

[0016] In another embodiment, the connecting element may be a joint having at least one transverse axis of rotation, advantageously an elastic joint.

[0017] In this embodiment, the distance between the free ends of the first and second support elements is therefore zero.

[0018] Whatever the embodiment, a removable fixing system may be provided, optionally adjustable, in particular in the longitudinal direction, which connects at least one support element to the connecting element, in order to facilitate the production and assembly of the trailing arms.

[0019] A fastening system may in particular comprise a first fastening element secured to a pulled arm near its second articulation or to a support element, a second fastening element secured to an anchoring element of the connecting element, the first and second fastening elements each being pierced with two corresponding orifices receiving screw-nut type fasteners, optionally at least one orifice having a dimension greater than the orifice with which it cooperates, in particular in an adjustment direction. The first and second fastening elements may in particular be part of a support element and / or form the support element. The anchoring element of the connecting element will for example be shaped to receive a ball-and-socket type articulation or an elastic articulation.

[0020] A fastening system may also comprise a first fastening element secured to a pulled arm near its second articulation or to a support element, a second fastening element secured to an anchoring element of the connecting element, the first fastening element having a threaded orifice, the second fastening element having a threaded rod extending parallel to the longitudinal direction and cooperating with the threaded orifice. In particular, the anchoring element may be secured to one of the ends of the threaded rod. The threaded rod may be held in position by one or two nuts, preferably two.

[0021] Each of these two variants may be used for one or both support elements. Advantageously, the first fixing element may be positioned relative to the support element or the trailing arm, outside a mounting area of ​​a second joint and / or machining of the trailing arm.

[0022] The invention finally relates to a vehicle equipped with a rear axle according to the invention.

[0023] The invention is now described with reference to the accompanying drawings and to the non-limiting examples, in which: [ Fig. 1 ] There figure 1 schematically represents in perspective a rear axle according to the prior art. Fig. 2 ] There figure 2 schematically represents a top view of the rear axle of the figure 1 in situation before (straight wheels) and after (inclined wheels) right turn. Fig. 3 ] There figure 3 schematically represents in perspective a rear axle according to an embodiment of the invention. Fig. 4 ] There figure 4 schematically represents a top view of the rear axle of the figure 3 in situation before (straight wheels) and after (inclined wheels) right turn. Fig. 5 ] There figure 5 schematically represents a top view of the connecting element according to another embodiment. Fig. 6 ] There figure 6 represents a top view of a system for fixing a connecting element according to one embodiment. Fig. 7 ] There figure 7 represents a top view of a system for fixing a connecting element according to another embodiment. Fig. 8 ] There figure 8 represents a perspective view of a system for fixing a connecting element according to another embodiment. Fig. 9 ] There figure 9 represents a top view of a system for fixing a connecting element according to another embodiment. Fig. 10 ] There figure 10 schematically represents, seen in the transverse direction, the roll kinematics of the joints of the twin and the arms of the rear axle of the figure 3 . [ Fig. 11 ] There figure 11 schematically represents, seen in the transverse direction, the roll kinematics of the joints of the twin of the rear axle of the figure 3 . [ Fig. 12 ] There figure 12 schematically represents, seen in the transverse direction (diagrams (a) and (b)) or seen from above (diagram (c), the pumping kinematics of the articulation of the rear axle of the figure 5 . [ Fig. 13 ] There figure 13 schematically represents, seen in the transverse direction, the roll kinematics of the joints of the twin of the rear axle of the figure 5 .

[0024] In this description, the terms front, rear, upper, lower, refer to the front and rear directions of the vehicle or the rear axle, when it is mounted on the vehicle, in other words in the position of use of the rear axle. The axes X, Y, Z, correspond respectively to the longitudinal (from front to back), transverse and vertical axis of the vehicle, the latter resting on the ground, or of the rear axle in the position of use. The vertical direction thus corresponds to the direction of gravity.

[0025] By substantially horizontal, longitudinal, transverse, or vertical, we mean a direction / plane forming an angle of at most ±20°, or even at most ±10° or at most ±5°, with a horizontal, longitudinal, transverse, or vertical direction / plane.

[0026] THE figures 3 And 4represent a rear axle 10 of a motor vehicle according to an embodiment of the invention. This rear axle 10 comprises two longitudinal trailing arms 1, 2. Each trailing arm 1, 2 has at a rear end a spindle support 3, 4. At an opposite front end, each trailing arm 1, 2 has a substantially transverse axis of rotation A1, A2 defined by a first articulation 5A, 6A and a second articulation 5B, 6B respectively, intended to be connected to the body of the vehicle. The axes of rotation A1, A2 of the trailing arms can each form an angle ranging from 0 to 15° with the transverse direction. When they form a non-zero angle with the transverse direction, each of the axes of rotation A1, A2 is then inclined towards the rear of the rear axle, as shown in the figures.

[0027] The second joints 5B, 6B are located between the first joints 5A, 6A transversely.

[0028] In the embodiment shown, each second articulation 5B, 6B is secured to an oblique arm 7, 8 respectively, each oblique arm extending from one of the trailing arms 1, 2 to which it is secured in an oblique direction towards the other trailing arm and towards the front of the rear axle. Each free front end of an oblique arm 7, 8 thus carries a second articulation 5B, 6B respectively. The invention is however not limited to a particular shape of the trailing arms, these being able for example to be in the form of a solid part, without free space between the oblique arms and the rest of the trailing arms.

[0029] Typically, the second joints 5B, 6B are located above the first joints 5A, 6A vertically and possibly behind them along the longitudinal axis of the vehicle.

[0030] The first and second joints are generally elastic joints, also called "bushing" or "silent block". This type of joint, well known, typically comprises two coaxial tubes mounted to rotate relative to each other and separated by a block of polymer material. An elastic joint is usually mounted inside a socket, the external tube being integral with this socket. In the figures, only the sockets receiving the elastic joints 5A, 6A, 5B, 6B and integral with the trailing arms 1, 2 or oblique arms 7, 8 are visible. The internal tubes of the elastic joints are integral with the body of the vehicle.

[0031] Each of the trailing arms 1, 2 can thus pivot around an axis of rotation A1, A2 defined by the two articulations 5A, 5B, respectively 6A, 6B, which connect it to the body of the vehicle. These axes of rotation A1, A2 intersect at a point of intersection I belonging to the longitudinal and vertical median plane of the rear axle. This plane is a transverse median plane of the rear axle extending in the longitudinal and vertical directions.

[0032] According to the invention, one of the trailing arms 1 is secured on the side of its second articulation 5B to a first support element 11 extending towards the front of the rear axle and the other trailing arm 2 is secured on the side of its second articulation 6B to a second support element 12 extending towards the rear of the axle. These support elements 11, 12 are here in the form of a curved arm, the invention is however not limited by the shape of the support elements. In addition, the free ends 11a, 12a of these first and second support elements 11, 12 are located in the longitudinal and vertical median plane of the rear axle and are connected to each other, and maintained at a fixed distance in the longitudinal direction, by a connecting element 13, in particular capable of transmitting forces in a substantially longitudinal direction X.

[0033] In the example shown figures 3 And 4, this connecting element 13 is an elongated part, also called a twin, each end of which is rotatably mounted on one of the free ends 11a, 12a of the support elements 11, 12, via an articulation 13a, 13b. Each articulation 13a, 13b has at least one transverse axis of rotation. In the example, this twin 13 is in the form of a simple flat plate, typically made of steel or aluminum. The axis A3 connecting the articulations 13a, 13b of the twin 13 further extends substantially parallel to the longitudinal direction of the rear axle, in the vertical and longitudinal median plane of the rear axle.

[0034] The non-zero distance separating the joints 13a, 13b may be chosen to be less than or equal to a threshold value. This threshold value may be determined by calculation and correspond, for example, to a maximum value of deformation acceptable by the rear axle. For example, this distance may be 30 to 70 mm, preferably 35 to 60 mm, or in any interval defined by two of these limits. This distance will preferably be as small as possible, a minimum distance being constrained by the dimensions of the joints 13a, 13b, for example ball joints, and / or by mounting constraints of the second joints 5B, 6B, and / or by machining constraints of the trailing arms.

[0035] As shown here, the joints 13a, 13b are located symmetrically on either side of the intersection point I in the longitudinal direction. The invention is however not limited to this arrangement and an asymmetrical position of the joints 13a, 13b is entirely conceivable.

[0036] In the example shown figures 3 And 4, the axis A3 intersects the axes of rotation A1 and A2 of the arms at the point of intersection I. Alternatively, this axis A3 could be located vertically above the point I (still in the vertical and longitudinal median plane of the rear axle), in particular at a non-zero distance, less than or equal to a threshold value. Such a raised position of the connecting element 13 makes it possible to improve the understeer-induced steering, as shown in the examples. The threshold value may be determined by calculation as a function of the maximum longitudinal travel authorized by the second articulations 5B, 6B. By way of example, the vertical position of the axis A3 of the connecting element relative to the point of intersection I may be from 0 to 35 mm, advantageously from 0 to 30 mm, from 5 to 25 mm or from 10 to 20 mm, or in any interval defined by two of these limits.

[0037] As shown by the arrows on the figure 4 , the presence of the connecting element 13 makes it possible to longitudinally constrain the relative position of the second articulations 5B, 6B during a right turn: the arms 1 and 2 and the wheels they carry see less variation in oversteer toe in comparison with the variation in toe observed figure 2 in the absence of a connecting element.

[0038] In the example shown figure 5 , the free ends 11a, 12a of the first and second support elements 11, 12 are connected by an articulation 14, here an elastic articulation, which will allow transmission of longitudinal forces. In the example, this elastic articulation 14 is inserted inside a sleeve 14a, integral with the free end 12a of the second support element. The axis of rotation 14b of the elastic articulation is fixed to a stirrup 14c integral with the free end 11a of the other support element 11. However, the positions of the stirrup and the sleeve could be reversed. In the example shown, the axis 14b of the articulation 14 is parallel to the transverse direction Y.

[0039] In this embodiment, the joint 14 is thus located at the point of intersection I of the axes of rotation of the trailing arms.

[0040] As in the other embodiment described with reference to figures 3 And 4, the articulation 14 can be located at the point of intersection I of the axes of rotation A1, A2 of the trailing arms 1, 2 or else be located vertically above this point of intersection. Similarly, by way of example, the vertical position of the connecting element 14 relative to the point of intersection I can thus be from 0 to 35 mm, advantageously from 0 to 15 mm or in any interval defined by two of these limits.

[0041] It will be noted that the behavior of the rear axle equipped with this central articulation 14 is similar to the behavior of the rear axle equipped with a twin 13 described with reference to the figure 4 .

[0042] The position of the support elements 11, 12 near the second articulations 5B, 6B may make it difficult to produce the socket receiving these articulations and their assembly as well as adjustment operations, for example adjustment of the wheel alignment. It may then be advantageous to provide a removable fixing system connecting the support elements and the connecting element. This fixing system will preferably be adjustable, in particular in the longitudinal direction. For example, a longitudinal adjustment of + / -6 mm may be provided.

[0043] Generally speaking, a fastening system may comprise at least two fastening elements, one of which is secured to the support element or the trailing arm (near its second articulation) and the other is secured to an anchoring element of the connecting element. These fastening elements may form all or part of the support element. Typically, at least one of the fastening elements is arranged so as, before assembly, not to hinder an operation of mounting a second articulation and / or manufacturing the trailing arm. In other words, this fastening element is not positioned inside a mounting zone of this second articulation and / or manufacturing of the trailing arm. Such a zone Z is shown as an example on the figure 9 .

[0044] Examples of fastening systems are described with reference to figures 6 à 9 .

[0045] There figure 6 represents a fixing system 200 comprising a first fixing lug 20 pierced with two orifices 20a, 20b, forming part of a support element 11 and a second fixing lug 21 also pierced with two orifices 21a, 21b and carrying a stirrup-type anchoring element 14c to receive the axis 14b of the articulation 14 represented figure 5 . This second fixing lug 21 forms another part of a support element 11. The first fixing lug 20 extends outside a mounting area of ​​the second articulation 5B and / or manufacturing of the trailing arm. The orifices of the two fixing lugs 20 and 21 correspond when they are superimposed, allowing their assembly by screw / nut systems. It will be noted that instead of the stirrup 14c, the second fixing lug 21 could have as an anchoring element the socket 14a or even an orifice for receiving an articulation of the binocular shown figure 3 . Whatever the embodiment, one of the orifices of one of the fixing lugs may have an oblong shape in order to allow adjustment, in particular in the longitudinal direction. In this embodiment, the support element 11 is thus formed from the assembly of the fixing lugs 20, 21.

[0046] There figure 7 represents a fixing system 201 comprising a ring 22 having a threaded orifice 22a and a threaded rod 23 extending in the longitudinal direction, one end of which is secured to the sleeve 14a of the articulation 14 of the figure 5 , this sleeve forming an anchoring element. The threaded rod 23 thus makes it possible to adjust the position of the sleeve 14a relative to the ring 22 and consequently to the support element. The ring 22 is fixed to the free end of the support element 12, outside a mounting zone of the second articulation 6B and / or manufacture of the trailing arm. Alternatively, the threaded rod 23 could be integral with the stirrup 14c as an anchoring element.

[0047] There figure 8 represents a fixing system 202 similar to that of the figure 7 , the threaded rod 23 carrying at its end one of the joints 13b of the twin 13 of the figure 3 .

[0048] There figure 9 represents an embodiment close to that described with reference to the figure 6 . Here, the fixing system 203 comprises a first fixing lug 24 pierced with two orifices 24a, 24b, forming a part of the support element 12 and a second fixing lug 25 also pierced with two orifices 25a, 25b and a third orifice 25c forming an anchoring element and receiving one 13b of the articulations of the twin 13 shown. figure 3 . This second fixing lug forms the other part of the support element 12. The orifices, 24a, 24b and 25a, 25b respectively, correspond when the two fixing lugs 24 and 25 are superimposed, allowing their assembly by screw / nut systems. In addition, one of the orifices 25a of the second plate 25 is oblong in shape allowing adjustment of the position of this second lug relative to the first lug 24. Here too, the support element 12 is formed by the assembly of the two lugs 24, 25. The first fixing lug 24 is furthermore outside the zone Z for mounting the second articulation 6B and / or manufacturing the trailing arm. Alternatively, the second fixing lug 25 could comprise, as an anchoring element, a socket 14a or a stirrup 14c as previously described.

[0049] The invention is not limited to a particular embodiment of the fixing system, provided that it allows removable mounting of the connecting element 13, 14. In addition, the different fixing systems described with reference to figures 6 à 9 can be combined and put in place indifferently for one or both support elements of the rear axle according to the invention. It will also be noted that the shape of the support elements and the fixing elements described with reference to the figures and / or their relative positions or their position in relation to the support element, the trailing arm or the oblique arm, can be modified depending on the environment of the rear axle and the shape of the trailing and oblique arms of the rear axle.

[0050] Each trailing arm, and possibly the associated oblique arm, can be made either from a raw casting, or by welding / embedding different parts or by boxing. Exemples

[0051] Examples 1 and 2 describe the kinematics of a rear axle equipped with a 13 twin whose distance between the axes of rotation is 40mm. The length of each trailing arm is 500mm.

[0052] Examples 3 and 4 describe the kinematic impact in pumping and rolling respectively of a rear axle equipped with a joint 14 vertically offset by 15mm. The length of each of the trailing arms is also 500mm. Example 1

[0053] There figure 10 shows the behavior of this rear axle in a 5° roll situation (87.27 mrad), in which the right trailing arm 2 pivots upwards (towards the impact) by 7° and the left trailing arm 1 pivots downwards (towards the rebound) by 7° as well (in the figure, the circles referenced 11a, 12a designate the position of the free ends of the support elements in the absence of roll, while the circles referenced 11'a, 12'a designate this position in a 5° roll). These rotations would cause, in the absence of the twin 13, a bringing together of the free ends of the support elements serving as anchoring points of the twin 13 by twice 0.15 mm (position 11'a, 12'a), which results in the fact that each articulation of the twin 13, and consequently each second articulation 5B, 6B, is forced longitudinally by 0.15 mm.This induces a right-hand steering (in left or right turns) of 0.15 / 500 = 0.3 mrad for a 500 mm long trailing arm, which represents an increase in the steering induced understeer of 0.34% compared to the 5° roll situation. The presence of the 13 twin thus has almost no impact on the roll behavior of the rear axle. We will note an identical steering in roll to the left or to the right. Example 2

[0054] THE figures 11 (a) à (c) show the kinematic impact of the presence of the binocular in roll when the binocular is vertically offset by 15mm above the intersection point I of the articulation axes of the trailing arms. In the figures, the circles symbolically represent the free ends 11a, 12a of the support elements serving as anchor points of the binocular, seen along the transverse axis Y.

[0055] There figure 11(a) schematically shows in the form of circles the free ends 11a, 12a in a straight-line rolling situation, the second articulations being unconstrained. Due to the raised position of the second articulations, the angle formed between the straight line passing through point I and each end 11a, 12a and the horizontal is 36.9°.

[0056] There figure 11(b) shows a vehicle roll situation at 5° (87.27mrad), in a left turn. The arms rotate 7.17° in the opposite direction. In the absence of a binocular, the free ends of the support elements serving as anchor points for the binocular would move closer together by twice 2.00mm (circles referenced 11"a and 12"a). They are kept at a constant distance by the binocular (circles referenced 11'a and 12'a) and constrain each second joint by approximately 2mm (depending on the local geometry) causing a rotation of a 500mm long trailing arm of 2 / 500=4mrad, which represents an increase in the understeer-induced steering of 4.6% compared to the 5° roll situation.

[0057] There figure 11(c) shows a situation of vehicle roll at 5°, in a right turn. The arms rotate 7.17° in the opposite direction. In the absence of a binocular, the free ends of the support elements serving as anchor points for the binocular (circles referenced 11"a and 12"a) would move apart by twice 1.7mm. They are kept at a constant distance by the binocular (circles referenced 11'a and 12'a) and constrain each second joint by approximately 1.7mm (depending on the local geometry) causing a rotation of a 500mm long trailing arm of 1.7 / 500=3.4mrad (11.7') which constitutes 3.9% of the roll. In other words, in this situation, the understeer-induced steering is increased by 3.9%.

[0058] This slightly asymmetrical behavior of the two trailing arms is negligible, this configuration allowing a significant gain in steering induced understeer (4.3% on average).

[0059] It should be noted that it is preferable to provide elastic joints (second joints) with sufficient longitudinal radial travel around the central point so as not to generate abnormal stresses on the train and to benefit from the expected effect. Example 3

[0060] THE figures 12 (a) à (c) show the kinematic impact in pumping.

[0061] There figure 12(a) shows a straight line situation in which the joint 14 is not prestressed and located 15mm above the axis of rotation of the trailing arms. The circles referenced 11a, 12a correspond respectively to the free ends 11a, 12a.

[0062] There figure 12(b) shows a shock pumping situation (Z displacement of +100mm) resulting in a rotation of the arms of 10.5° in the same direction. The figure 12(c) is a top view of this position. The free end 12'a attached to the right trailing arm is shifted forward by 2.7 mm and shifted to the left by 2.7 mm, forcing the central articulation by 2.7 x sin10° = 0.48 mm (the 10° angle being the angle between the articulation axis A1 and the transverse axis Y). The free end 11'a attached to the left trailing arm is shifted forward by 2.7 mm and shifted to the right by 2.7 mm, forcing the central articulation by 2.7 x sin10° = 0.48 mm. Overall, the joint is thus forced to deform laterally by 0.48 + 0.48 mm, or approximately 1 mm, which is acceptable. Example 4

[0063] There figure 13 (a) represents a rolling situation in which the central joint is unconstrained. The circles referenced 11a, 12a correspond respectively to the free ends 11a, 12a. The figure 13(b)represents a 5° roll situation (left turn). The arms rotate 7.17° in opposite directions. In the absence of articulation, the free ends of the support elements would move apart by twice 1.9mm (circles referenced 11"a, 12"a). They are held at a zero distance by articulation 14 (circle referenced 11'a) and constrain each second articulation by approximately 1.9mm (depending on the local geometry) causing a rotation of a 500mm long trailing arm of 1.9 / 500=3.8mrad, which represents an increase in the understeer-induced steering of 4.3% compared to the 5° roll situation.

Claims

1. Motor vehicle rear suspension (10) of the type having two longitudinal trailing arms (1, 2), wherein each trailing arm (1, 2) has a stub-axle carrier (3, 4) at one, rear, end and, at an opposite, front, end, a substantially transverse axis of rotation (A1, A2) defined by a first articulation and a second articulation which are intended to be connected to the body of the vehicle, the second articulations (5B, 6B) being situated transversely between the first articulations, and the axes of rotation (A1, A2) of the trailing arms being secant at a point of intersection (I) belonging to a transversely mid-plane of the rear suspension, this plane extending in the longitudinal and vertical directions, characterized in that: - one (7) of the trailing arms is secured, at its second articulation, to a first support element (11) extending toward the front of the rear suspension, - the other (8) trailing arm is secured, at its second articulation, to a second support element (12) extending toward the rear of the rear suspension, - free ends (11a, 12a) of the first and second support elements are situated in the longitudinal and vertical midplane of the rear suspension and are connected to one another and held at a fixed distance apart in a substantially longitudinal direction by a connecting element (13, 14) that is pivotably mounted about at least one transverse axis at least at one of the free ends of the first and second support elements.

2. Rear suspension (10) according to Claim 1, characterized in that the fixed distance separating the free ends of the first and second support elements is comprised within an interval ranging from zero to a threshold value.

3. Rear suspension (10) according to either of Claims 1 and 2, characterized in that the connecting element (13, 14) extends vertically above the point of intersection (I) of the axes of rotation of the trailing arms, notably at a non-zero distance less than or equal to a threshold value.

4. Rear suspension (10) according to any one of Claims 1 to 3, characterized in that the connecting element (13) is an elongate component having two ends that are distant in the longitudinal direction, each of the ends being pivotably mounted at one of the free ends of the first and second support elements about at least one transverse axis of rotation.

5. Rear suspension (10) according to Claim 4, characterized in that the ends of the elongate component (13) are articulated to the free ends (11a, 12a) of the first and second support elements by articulations (13a, 13b) having at least one transverse axis of rotation.

6. Rear suspension (10) according to any one of Claims 1 to 3, characterized in that the connecting element (14) is an articulation having at least one transverse axis of rotation, optionally an elastic articulation.

7. Rear suspension (10) according to any one of Claims 1 to 6, characterized in that a removable fixing system (200, 201, 202, 203), optionally adjustable, notably in the longitudinal direction, connects at least one support element (11, 12) to the connecting element (13, 14).

8. Rear suspension (10) according to Claim 7, characterized in that the fixing system is selected from among: - a first fixing element (20, 24) secured to a trailing arm near the second articulation thereof or a support element, a second fixing element (21, 25) secured to an anchoring element of the connecting element, the first and second fixing elements each being pierced with two corresponding orifices (20a, 20b; 21a, 21b; 24a, 24b; 25a, 25b) accepting fixings of the screw-nut type, optionally at least one orifice (25a) having a larger dimension than the orifice with which it collaborates, notably in an adjustment direction, - a first fixing element secured to a trailing arm near the second articulation thereof or a support element, a second fixing element secured to an anchoring element of the connecting element, the first fixing element having a threaded orifice (22a), the second fixing element having a threaded rod (23) extending parallel to the longitudinal direction and engaging with the threaded orifice.

9. Motor vehicle equipped with a rear suspension (10) according to any one of Claims 1 to 8.