ARRANGEMENT OF A SEMI-RIGID AXLE IN A MOTOR VEHICLE

Abstract

The invention relates to an arrangement of an axle (10) in a motor vehicle, the axle (10) comprising: - a cross member (14) with a transverse axis (Y1) which is elastically deformable in torsion; - two generally longitudinal parallel arms (12), each of which is intended to be connected to a body (19) of the motor vehicle and each of which is rigidly fixed to an external transverse end (30) of the cross member (14), - at least one elastic articulation (32) for connecting each arm (12) in pivoting to the body (19) of the vehicle, each elastic articulation (32) comprising an external tubular frame (34) concentrically housing an internal frame (38) with radial interposition of an elastic ring (46), characterized in that the external frame (34) is connected to the body (19) of the motor vehicle while the internal frame (38) is fixed to the arm (12) of the axle (10). Figure for short: Figure 5

Description

Title of the invention: ARRANGEMENT OF A SEMI-RIGID AXLE IN A MOTOR VEHICLE TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to an arrangement of an axle in a motor vehicle, the axle comprising:

[0002] - a transverse axis crosspiece which is elastically deformable in torsion;

[0003] - two generally longitudinal parallel arms, each of which is intended to be linked to a body of the motor vehicle and each of which is rigidly fixed to an external transverse end of the crossmember,

[0004] - at least one elastic joint for connecting each pivoting arm to the body of the vehicle, each elastic joint comprising an external tubular frame concentrically housing an internal frame with radial interposition of an elastic ring. TECHNICAL BACKGROUND OF THE INVENTION

[0005] The state of the art includes documents DE-10 2014 001307-A1, EP-0.352.449-A1, EP-0.914.977-B1 and DE-19535521-A1.

[0006] It is known to equip the rear axles of motor vehicles with a "semi-rigid" type axle. Such an axle mainly comprises two longitudinal arms between which extends a torsionally elastic and flexurally rigid crossmember. Each arm is connected to the crossmember by a recess-type connection.

[0007] Each arm has a front end which is pivotally mounted on the vehicle body while a rear end carries a rear wheel of the vehicle.

[0008] The crossmember extends transversely between the two arms, offset longitudinally rearwardly relative to the front ends of the arms. The elastic properties of the crossmember enable it in particular to perform an anti-roll function which limits the rolling of the bodywork. It is, for example, known to produce tubular crossmembers from steel.

[0009] It is known to articulate each end of the suspension arm on the vehicle body by means of an elastic joint, sometimes referred to as a "silentbloc" or "flexibloc". Such an elastic joint has the advantage of eliminating mechanical play between the arm and its support. In addition, the elastic joint makes it possible to filter certain vibrations between the wheel and the vehicle chassis.

[0010] Such an articulation conventionally comprises a tubular external frame, an internal frame arranged concentrically inside the external frame, and a ring made of elastomeric material interposed radially between the two frames.

[0011] Such an elastic joint allows limited pivoting of the arm relative to the body by twisting the ring made of elastomer material around the main axis of the joint.

[0012] Systematically, the person skilled in the art traditionally connects the external frame to the arm and the internal frame to the vehicle body. More particularly, the internal frame comprises a fixing pin which projects axially on either side of the external frame. The two ends of these pins are received in a yoke fixed to the vehicle body. The external frame is for its part inserted by force into an eyelet made at one end of the arm.

[0013] Such a design is usually satisfactory, especially when the axle arm is arranged below the level of the vehicle seats.

[0014] However, this arrangement is cumbersome and does not offer an alternative when one wishes to modify the architecture of the vehicle.

[0015] For example, to improve passenger comfort by increasing the absorption of shocks of the wheels with obstacles, it is preferable to install the joints above the axes of rotation of the wheels associated with said axle. However, in such an arrangement, the elastic joints interfere with the vehicle seats. BRIEF SUMMARY OF THE INVENTION

[0016] The invention provides an arrangement of an axle in a motor vehicle, the axle comprising:

[0017] - a transverse axis crosspiece which is elastically deformable in torsion;

[0018] - two generally longitudinal parallel arms, each of which is intended to be linked to a body of the motor vehicle and each of which is rigidly fixed to an external transverse end of the crossmember,

[0019] - at least one elastic joint for connecting each pivoting arm to the body of the vehicle, each elastic joint comprising an external tubular frame concentrically housing an internal frame with radial interposition of an elastic ring,

[0020] characterized in that the external frame is connected to the body of the motor vehicle while the internal frame is fixed to the axle arm.

[0021] According to another characteristic of the invention, the elastic joint is offset transversely outwards relative to the arm.

[0022] According to another characteristic of the invention, the internal frame is fixed to an internal fixing member on the arm which projects transversely inwards relative to the external frame.

[0023] According to another characteristic of the invention, the internal frame is fixed to an articulation end of the associated arm.

[0024] According to another characteristic of the invention, the motor vehicle comprises at least two wheels rotatably mounted on the axle, the articulation end of the arm being located vertically above the axis of rotation of the associated wheel.

[0025] According to another characteristic of the invention, the motor vehicle comprises at least one seat which is arranged substantially vertically above the axle near an arm, the elastic articulation associated with said arm being offset transversely outwards relative to said seat.

[0026] According to another characteristic of the invention, the external frame is connected to the body by means of a bearing which is itself fixed to the body.

[0027] According to another characteristic of the invention, the bearing is entirely offset transversely towards the outside by the seat.

[0028] According to another characteristic of the invention, the elastic joint is arranged substantially vertically at the same level as a seat base.

[0029] According to another characteristic of the invention, the axle is arranged longitudinally at the rear of the vehicle in the normal direction of movement of the vehicle. BRIEF DESCRIPTION OF THE FIGURES

[0030] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings briefly described below.

[0031] [Fig.l] is a perspective view which schematically represents a semi-rigid axle intended to be arranged on a motor vehicle according to the arrangement of the invention.

[0032] [Fig. 2] is a perspective view which represents an elastic articulation intended to connect an arm of the axle of [Fig. 1] to a body of the motor vehicle according to the teachings of the invention.

[0033] [Fig. 3] is a side view showing a left arm of the axle of [Fig. 1] connected to the body of a motor vehicle by means of the elastic joint of [Fig. 2] according to the teachings of the invention.

[0034] [Fig.4] is a vertical cross-sectional view along section plane 4-4 of [Fig.3] which represents the elastic joint linked to the arm according to the arrangement produced according to the teachings of the invention.

[0035] [Fig.5] is a bottom view of the arrangement shown in [Fig.3] which shows the elastic joint offset transversely outwardly relative to the arm according to the teachings of the invention.

[0036] [Fig.6] is a sectional view along section plane 6-6 of [Fig.5] which represents the transverse offset of the elastic joint and the arm relative to a seat base of a motor vehicle seat.

[0037] [Fig.7] is a perspective view showing the underside of the axle arranged on the motor vehicle. DETAILED DESCRIPTION OF THE FIGURES

[0038] In the remainder of the description, elements having an identical structure or similar functions will be designated by the same references.

[0039] In the remainder of the description, longitudinal, vertical and transverse orientations indicated by the trihedron "L,V,T" of the figures will be adopted, without limitation. The longitudinal direction "L" is oriented from back to front in the normal direction of movement of the vehicle. The vertical direction "V" is oriented from bottom to top from the ground on which the vehicle rests towards the roof of the vehicle.

[0040] A local reference frame attached to each elastic joint 32 will also be adopted and comprising an axial orientation "A" parallel to the main axis "Y2" of the elastic joint 32, radial orientations directed orthogonally from the main axis "Y2" of the elastic joint, and tangential orientations directed orthogonally to the radial and axial orientations.

[0041] In the following, the term "inner" will designate an element facing transversely towards the center of the vehicle, while the term "outer" will designate an element facing in the opposite direction. The term "inner" will designate an element facing radially towards the axis "Y2" of the elastic joint 32 while the term "outer" will designate an element facing in an opposite direction.

[0042] [Fig.l] shows a rear axle 10 of a motor vehicle. This is an axle 10 of the "semi-rigid" type. It comprises two parallel arms 12, called longitudinal arms 12, each of which has a generally longitudinal main axis "XI". The two longitudinal arms 12 are connected to each other by a cross member 14 with a transverse main axis "Yl".

[0043] Each longitudinal arm 12 extends from a first front end 16 to a second rear end 18. The first front end 16 is intended to be pivotally mounted about a generally transverse axis “Y2” on a body 19 of the vehicle as will be explained in more detail later. This front end 16 will therefore be called hereinafter “articulation end 16”.

[0044] A rear end section of each longitudinal arm 12 is provided with a bracket 20 which is intended to support in a rotatable manner, around a transverse axis “Y3”, an associated rear wheel 21 of the vehicle of which only one brake disc 22 or drum associated with the wheel is shown in [Fig.l].

[0045] The motor vehicle thus comprises at least two wheels 21 each rotatably mounted on one of the arms 16 of the axle 10. The wheels 21 are here coaxial with axis “Y3”.

[0046] In the embodiment shown in [Fig.l], the longitudinal arm 12 also comprises a yoke 24 for supporting a shock absorber element 26, and a cup 28 for supporting a vehicle suspension member 29.

[0047] The crosspiece 14 extends from a first transverse end section 30 to a second transverse end section 30.

[0048] The crosspiece 14 is here in the form of a steel tube. At least the transverse end sections 30 of the crosspiece 14 have, in section along a longitudinal vertical plane, a closed profile. In the non-limiting example shown in [Fig.l], the crosspiece 14 has a closed profile over its entire length.

[0049] The crosspiece 14 is made so as to be rigid in bending in the vertical plane and in the longitudinal plane and so as to be flexible in torsion around its main transverse axis "Y2". The wall of the crosspiece 14 has sufficient flexibility in torsion to perform its anti-roll function.

[0050] Each end section 30 of the crosspiece 14 is rigidly fixed to the associated longitudinal arm 12.

[0051] The first end 16 of each arm 12 is pivotally mounted around the body 19 of the vehicle by means of an elastic joint 32.

[0052] In Figures 2 to 7, only one of the two elastic joints 32 is shown, here the one associated with the left arm 12. The elastic joint 32 equipping the other arm 12 is identical and it is arranged symmetrically with respect to a vertical longitudinal plane passing through the center of the crosspiece 14. The following description will therefore be applicable to the other elastic joint 32 associated with the right arm 12 and to its arrangement.

[0053] [Fig. 2] shows such an elastic joint 32. The elastic joint 32 comprises a main axis "Y2" of axial orientation. As can be seen in [Fig. 5], said axis "Y2" is generally oriented transversely, but here it is slightly inclined in a transverse longitudinal plane.

[0054] In a known manner, such an elastic joint 32 comprises a frame 34 external cylindrical tubular with an axis substantially coaxial with the main axis "Y2". The external frame 34 is delimited radially by a cylindrical external face 36, here with a circular profile and by a cylindrical internal face 37, here with a circular profile.

[0055] The elastic joint 32 also comprises an internal frame 38 having a cylindrical tubular wall with an axis coaxial with the main axis "Y2". The wall is delimited by a cylindrical internal face 40, here with a circular profile, circumscribing a central orifice 42 and by a cylindrical external face 44, here with a circular profile.

[0056] The internal frame 38 is arranged concentrically inside the external frame 34.

[0057] A ring 46 with an axis coaxial with the main axis "Y2" made of elastomer material is interposed radially between the internal face 37 of the external frame 34 and the external face 44 of the internal frame 38. The ring 46 of elastomer material is for example mounted prestressed in radial compression between the two frames 34, 38.

[0058] The external and internal frames 34, 38 are here made of a reinforced plastic material or of a metallic material such as steel or aluminum.

[0059] The external frame 34 is connected to the body 19 of the motor vehicle while the internal frame 38 is fixed to the arm 12 of the axle 10. This makes it possible to transversely shift the elastic articulation 32 transversely relative to the arm 12.

[0060] More particularly, each elastic articulation 32 is offset transversely outwards relative to the associated arm 12. This thus makes it possible to transversely separate the two articulation axes “Y3” and thus to obtain more stable support for the vehicle.

[0061] Furthermore, such an arrangement of the elastic joints 32 makes it possible to provide greater freedom for arranging the axle 10 in the vehicle.

[0062] The internal frame 38 is here fixed to the articulation end 16 of the arm 12. The internal frame 38 is here extended transversely by an internal fixing member 48 on the arm 12 which protrudes transversely inwards relative to the external frame 34.

[0063] The internal member 48 is here formed by a shaft, an external end portion 50 of which is inserted into the central orifice 42 of the internal frame 38. The shaft is for example held by force insertion, but it can also be fixed by any other known means such as gluing, welding, hooping, etc.

[0064] To reduce the transverse bulk of the arrangement, the outer end portion 50 does not substantially protrude transversely outwards relative to the external frame 34.

[0065] As shown in Figures 4 and 5, an inner end portion 52 of the shaft projects transversely inwardly relative to the outer frame 34. This inner end portion 52 is fixed to the articulation end 16 of the arm 12, for example by force-fitting into an eyelet 54 of the articulation end 16 of the arm 12, but it can also be fixed by any other known means such as gluing, welding, hooping, etc. The arm 12 is in particular fixed to the associated elastic articulation 32 solely by means of the inner end portion 52.

[0066] The external frame 34 is connected to the body 19 by means of a bearing 55 which is itself fixed to the body 19. The bearing 55 has an orifice 58 receiving the frame 34 external. The external armature 34 is preferably received with a tight fit in the hole 58 of the bearing 55.

[0067] The bearing 55 is here fixed to the body 19 by means of fixing lugs 60. Each lug 60 is arranged flat against one face of the body 19. Each lug 19 here extends longitudinally on either side of the bearing 55 in order to reduce the transverse size of the joint. Each fixing lug 60 is for example fixed to the body by screwing, by welding or by any other suitable fixing means.

[0068] As shown in [Fig.3], the articulation end 16 of each arm 12 is preferably located vertically above the axis “Y3” of rotation of the associated wheel 21. Thus, the axes “XI” of the arms 12 are slightly inclined relative to the strictly longitudinal direction. This makes it possible in particular to improve comfort for the passengers of the vehicle.

[0069] Furthermore, as shown in Figures 3, 5, 6 and 7, the motor vehicle comprises at least one seat 56 which is arranged substantially vertically above the axle 10 near an arm 12 of the axle.

[0070] In this case, in the case of an axle 10 which is arranged longitudinally towards the rear of the vehicle, the seat 56 is part of a rear bench seat which occupies the entire width of the passenger compartment.

[0071] This arrangement makes it possible to offset the elastic joint 32 associated with said arm 12 transversely outwards relative to said seat 56. Thus the elastic joint 32 can be arranged substantially vertically at the same level as a seat 62 of the seat 56 without interfering with the latter. The bearing 55 is in particular entirely offset transversely outwards relative to the seat 56. As shown in [Fig.7], the assembly formed by the articulation end 16 of the arm 12 and the elastic joint 32 is arranged at a transverse distance “D” from the seat 62 of the seat 56.

[0072] This arrangement advantageously makes it possible to transversely space the elastic joints 32 associated with each arm 12 of the axle. In particular, it makes it possible to accommodate the elastic joints 32 on either side of seats 56 for the passengers of a motor vehicle.

[0073] The size of the connection of the arms 12 to the body 19 is thus advantageously reduced transversely while making it possible to obtain a solid fixing of the elastic articulation 32 to the body 19 by means of the bearing 55.

[0074] Furthermore, this arrangement makes it possible to space the elastic joints 32 transversely from each other to obtain a more stable and more comfortable suspension.

Claims

Claims

1. Arrangement of an axle (10) in a motor vehicle, the axle (10) comprising: - a cross member (14) with a transverse axis (Y 1) which is elastically deformable in torsion;- two generally longitudinal parallel arms (12), each of which is intended to be connected to a body (19) of the motor vehicle and each of which is rigidly fixed to an external transverse end (30) of the crossmember (14), - at least one elastic articulation (32) for connecting each arm (12) in pivoting to the body (19) of the vehicle, each elastic articulation (32) comprising an external tubular frame (34) concentrically housing an internal frame (38) with radial interposition of an elastic ring (46), the external frame (34) being connected to the body (19) of the motor vehicle while the internal frame (38) is fixed to the arm (12) of the axle (10), characterized in that the motor vehicle comprises at least one seat (56) which is arranged substantially vertically above the axle (10) near an arm (12), the elastic articulation (32) associated with said arm (12) being offset transversely outwardly relative to said seat (56).;

2. Arrangement according to the preceding claim, characterized in that the elastic articulation (32) is offset transversely outwards relative to the arm (12).

3. Arrangement according to any one of the preceding claims, characterized in that the internal frame (38) is fixed to an internal fixing member (48) on the arm (12) which projects transversely inwards relative to the external frame (34).

4. Arrangement according to any one of the preceding claims, characterized in that the internal frame (38) is fixed to an articulation end (16) of the associated arm (12).

5. Arrangement according to the preceding claim, characterized in that the motor vehicle comprises at least two wheels (21) rotatably mounted on the axle (10), the articulation end (16) of the arm (12) being located vertically above the axis (Y3) of rotation of the associated wheel (21).

6. Arrangement according to any one of the preceding claims, characterized in that the external frame (34) is connected to the body (19) by means of a bearing (55) which is itself fixed to the body (19).

7. Arrangement according to the preceding claim, characterized in that the bearing (55) is entirely offset transversely outwards relative to the seat (56).

8. Arrangement according to any one of claims 1 to 7, characterized in that the elastic articulation (32) is arranged substantially vertically at the same level as a seat (62) of the seat (56).

9. Arrangement according to any one of the preceding claims, characterized in that the axle (10) is arranged longitudinally at the rear of the vehicle in the normal direction of travel of the vehicle.

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