Transmission joint for suspended axle of motor vehicle

Abstract

The invention provides a transmission joint (30) comprising: a rotation axis (32), a first hub (34) connected to a first shaft (24), a second hub (36) connected to a second shaft (26); and a plurality of bars (38) extending axially and distributed around the rotation axis (32). The plurality of bars (38) comprises a first bar (40) fixed to the first hub; and a second bar (42) fixed to the second hub. The bars are free to translate relative to the first or second hub. The transmission joint (30) includes a transmission sphere (44) axially engaged in the first and second bars to transmit torque from the first hub (34) to the second hub (36) via the first and second bars (40 and 42). Application to a transmission between a front engine and the rear wheels of a motor vehicle. Figure to be published with the abbreviation: Figure 5

Description

Title of the invention: Transmission joint for a suspended axle of a motor vehicle

[0001] The invention relates to the transmission of torque between two tiltable shafts that move apart during their rotation. More specifically, the invention relates to a bar-type transmission joint for the drive of a motor vehicle. The invention also relates to a motor vehicle.

[0002] Rear-wheel drive, front-engine motor vehicles use a driveshaft to transmit the rotational motion generated by the engine to the rear wheels. Some of these vehicles are equipped with a rear axle assembly comprising a rigid axle and a suspension using leaf springs.

[0003] However, a rear axle equipped with a leaf spring does not deflect strictly along the vertical axis. The leaf spring compresses, causing the connection between the leaf spring and the vehicle structure to pivot, resulting in a slight variation in the wheelbase relative to the position of the rear wheels. The driveshaft must then cope with angular misalignment as well as a variation in its length.

[0004] Despite this variation, the transmission must remain continuous, especially in the case of rear-wheel drive. A universal joint is generally installed on the longitudinal driveshaft to correct angular misalignments, typically up to 45 degrees. The universal joint is mounted in series with a sliding joint designed to compensate for wheelbase variations.

[0005] Such a configuration, requiring two joints mounted in series to ensure the transmission of movement to the rear axle during wheelbase variations, generates costs related to the supply of two different parts; as well as their assembly and maintenance.

[0006] A known solution consists of adding oblong holes to the universal joint at the point where the cross member is attached, ensuring the angular transmission of motion. These oblong holes allow the cross member to slide axially, thus making it possible to effectively correct axial misalignments. This solution provides a few millimeters of axial correction, combined with a few degrees of angular misalignment correction. However, there is a need to increase the axial correction range and extend the angular travel between the input and output shafts.

[0007] Document CN109139722 A describes a coupling with three bars connecting the input and output shafts with axial misalignment correction. Such a system allows for efficient transmission of rotational torque in the case of a variation in length, it remains incompatible with an angular misalignment between the inlet and the outlet.

[0008] Document FR3056657 A1 describes a coupling with three bars connecting the input and output shafts. Variations in transmission length are compensated by the sliding of said bars. A coupling element, elastically deformable in bending, allows slight angular displacements, on the order of 0.5 degrees, of the transmission's geometric axis. The possibilities for angular misalignment of the transmission therefore remain limited.

[0009] US patent 7497781 B2 describes a drive shaft with flexible bars that help correct angular misalignments. Conversely, the ability to correct length variations remains limited. Furthermore, this drive shaft is limited in terms of transmissible torque. The elasticity of the bars generates vibration phenomena that can propagate through the output shaft. For a given angular inclination, the vertical and lateral position of the output shaft relative to the input shaft is random.

[0010] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to increase the axial and angular travel of a torque transmission. The invention also aims to optimize the travel, cost, angular stiffness, and assembly of a transmission joint, particularly for motor vehicles.

[0011] According to a first aspect, the invention provides a transmission joint for coupling a first shaft to a second shaft; the transmission joint comprising: a rotation axis, a first hub for being connected to the first shaft, a second hub for being connected to the second shaft; a plurality of bars around the rotation axis extending axially; notable in that the plurality of bars comprises a first bar fixed to the first hub; a second bar fixed to the second hub; at least one of the first bar and the second bar being able to slide axially relative to the first hub or the second hub; the transmission joint further comprising a transmission sphere engaged axially in the first bar and in the second bar in order to transmit a torque from the first hub to the second hub via the first and second bars.

[0012] The invention allows both tilt compensation and axial offset compensation between the shafts. Thus, the invention extends the adaptation ranges of a transmission joint during its operation.

[0013] Preferably, the first bar comprises a first cavity opposite the first hub, the second bar comprises a second cavity opposite the second hub; the transmission sphere being housed in the first cavity and the second cavity.

[0014] Preferably, the transmission sphere comprises an arc housed in the first bar, said arc describing an obtuse angle.

[0015] Preferably, said obtuse angle is greater than or equal to 120°.

[0016] Preferably, the first bar includes a first circular contact zone against the transmission sphere; and the second bar includes a second circular contact zone against the transmission sphere.

[0017] Preferably, the first contact zone and the second contact zone are circular edges.

[0018] Preferably, the first bar includes a first axial stop opposite the transmission sphere and / or the second bar includes a second axial stop opposite the transmission sphere.

[0019] Preferably, the first bar comprises a first diameter, the transmission sphere comprises a second diameter smaller than the first diameter.

[0020] Preferably, the first bar includes an outer spoke, the first hub includes a disc with a thickness greater than the outer spoke; preferably, the first bar is mounted in said disc via a sliding connection.

[0021] Preferably, the first bar is at a distance from the second bar.

[0022] Preferably, the first bar, the second bar and the transmission sphere are configured so that the second hub can be tilted relative to the first hub by an angle of inclination of at least 5°, more preferably of at least 45°.

[0023] Preferably, the first bar and the second bar form a first pair of bars; the plurality of bars also includes second pairs of bars identical to the first pair, the transmission sphere is a first transmission sphere; the transmission joint further includes a second transmission sphere associated with each second pair of bars.

[0024] Preferably, the first bar and the second bar are tubular and include cylindrical recesses extending over the entire first and second bars respectively; the transmission sphere extending into said cylindrical recesses.

[0025] Preferably, the bars of the plurality of bars are parallel.

[0026] Preferably, the angle of inclination is at least 10°.

[0027] Preferably, the angle of inclination is at least 20°.

[0028] Preferably, the angle of inclination is at least 30°.

[0029] Preferably, the angle of inclination is at least 55°.

[0030] According to another aspect, the invention proposes a transmission joint between two shafts; the transmission joint comprising: a first hub, a second hub; a plurality of bars distributed around the first hub and the second hub; remarkable in that the plurality of bars comprises first bars fixed to the first hub; second bars fixed to the second hub; said first bars and second bars being able to slide axially relative to the first hub or the second hub; the transmission joint having an axially junction interface between the first bars and the second bars, said junction interface comprising transmission spheres engaged axially in the first bars and in the second bars in order to transmit a torque from the first hub to the second hub via the plurality of bars.Such a transmission joint increases the range of axial and angular displacement, and therefore the adaptive capabilities.

[0031] According to another aspect, the invention proposes a motor vehicle comprising a transmission joint; remarkable in that the transmission joint conforms to the invention.

[0032] Preferably, the motor vehicle comprises a front engine, a rear axle comprising: rear wheels, a suspension system with leaf springs; the rear wheels being coupled to the front engine via said transmission joint.

[0033] Preferably, the suspension system includes a crossbeam connecting the rear wheels, the first shaft being joined to the engine, the second shaft being joined to the crossbeam.

[0034] Preferably, the crossbeam is fixed to the leaf springs.

[0035] Each feature introduced by the expression "preferably" given in relation to one of the aspects of the invention applies to all other aspects of the invention.

[0036] The invention will be well understood and other aspects and advantages will become clear upon reading the following description, given with reference to the attached figures listed below.

[0037] Fig. 1 is a side view of a motor vehicle according to the invention.

[0038] Figure 2 shows a transmission joint according to the invention.

[0039] Figure 3 shows a transmission joint according to the invention.

[0040] Figure 4 shows a transmission joint according to the invention.

[0041] Figure 5 shows a transmission joint according to the invention.

[0042] Figure 6 shows a transmission joint according to the invention.

[0043] The [Fig.7] is a cross-section of a pair of bars at the level of a transmission sphere of transmission joint according to the invention.

[0044] In the following description, the term "include" is synonymous with "include" and is not limiting in that it permits the presence of other elements in the motor vehicle or the transmission joint to which it relates. It is understood that the term "include" includes the terms "consist of." The terms "external" and "internal" shall respectively refer to what is directed outward from the vehicle and inward from the vehicle.

[0045] In this description, the terms "longitudinal," "longitudinally," "transverse," and "transversely" are used with respect to the vehicle's frame of reference in the mounting configuration. The term "longitudinal" refers to the principal direction of travel of the vehicle. The term "transverse" refers to a direction perpendicular to the principal direction of travel of the vehicle. The term "front" refers to the principal direction of travel of the vehicle. The term "rear" refers to the opposite of the front of the vehicle.

[0046] The X axis represents the longitudinal direction, the Y axis represents the transverse direction, and the Z axis represents the vertical direction of the motor vehicle.

[0047] In this description, the ranges of values ​​include the bounds that delimit them.

[0048] In this description, the technical characteristics are defined in a transmission joint configuration in which the first shaft and the second shaft are aligned; unless otherwise explicitly stated.

[0049] Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

[0050] Figure 1 represents a motor vehicle 10, according to an embodiment of the invention. The motor vehicle 10 includes energy storage means (not shown) adapted to power said motor vehicle 10.

[0051] The motor vehicle 10 comprises a structure 12. The structure 12 forms an outer body, or chassis, of the motor vehicle. The structure 12 defines a passenger compartment and connects various parts of the motor vehicle 10, including the openings. The structure 12 forms a mounting support for the suspension systems, the steering system, the braking systems, and an engine such as a front motor 14. The front motor 14 is an electric motor or an internal combustion engine.

[0052] The motor vehicle 10 comprises a rear axle with rear wheels 16 connected to the structure 12 via a suspension system 18. The suspension system 18 allows vertical movement of the rear wheels 16, which improves road holding and passenger comfort. The vertical oscillations of the rear wheels 16 are then accompanied by a longitudinal movement, and therefore a variation in wheelbase.

[0053] To simplify the joints of the suspension system 18, the latter has a crossbeam 20. The crossbeam 20 is horizontal and essentially rigid. The crossbeam 20 connects the rear wheels 16. The suspension system 18 includes leaf springs 28. The leaf springs 28 provide elastic means between the rear wheels 16 and the structure 12. They simplify the suspension system 18.

[0054] The motor vehicle 10 has a transmission system 22 between the front engine 14 and the rear wheels 16. The transmission system 22 comprises rotating shafts, including a first shaft 24 and a second shaft 26. The first shaft 24 is a front shaft. It is coupled to the front engine 14. Its axis of rotation is fixed relative to the structure 12. The second shaft 26 is a rear shaft. It is fixed to the rear wheels 16, in particular to the crossbeam 20. During the oscillation movements of the suspension system 18, the second shaft 26 also oscillates. In particular, its axis of rotation oscillates and moves axially.

[0055] The first shaft 24 and the second shaft 26 are connected via a transmission joint 30. The transmission joint 30 allows the transmission of torque between the shafts, as well as a variation in relative inclination and a variation in elongation. Consequently, the rear wheels 16 are driven by the front motor 14 via said transmission joint 30.

[0056] The motor vehicle can, for example, be a private motor vehicle or a commercial motor vehicle.

[0057] Figure 2 shows a transmission joint 30 for a motor vehicle, according to an embodiment of the invention. The motor vehicle may correspond to the one shown in relation to Figure 1.

[0058] The transmission joint 30 is a coupling device. The transmission joint 30 has a rotation axis 32. The rotation axis 32 is a geometric axis. It can be straight when the first shaft and the second shaft are aligned. The transmission joint 30 rotates about the rotation axis 32.

[0059] The transmission joint 30 comprises a first hub 34 for connection to the first shaft, and a second hub 36 for connection to the second shaft and axially opposite to the first hub 34. The hubs are connected by a plurality of bars 38. The bars 38 are arranged around the axis of rotation 32. They are angularly distributed around the axis of rotation 32. The bars 38 extend axially. They are axial bars. They are parallel to the axis of rotation 32. They form rigid bodies.

[0060] The plurality of bars 38 comprises a first bar 40 fixed to the first hub 34; a second bar 42 fixed to the second hub 36. The first bar 40 slides axially relative to the first hub 34. The second bar 42 slides axially relative to the second hub 36. They are connected via sliding links, like sliding pivots.

[0061] The transmission joint 30 further includes a transmission sphere 44 engaged axially in the first bar 40 and in the second bar 42 in order to transmit a torque from the first hub 34 to the second hub 36 via the first bar 40 and the second bar 42. The transmission sphere 44 can be a solid sphere or a hollow sphere.

[0062] Thus, the transmission joint 30 compensates for axial movements between the first shaft 40 and the second shaft 42, as well as variations in inclination, while transmitting torque at a given rotational speed. Therefore, the transmission joint 30 increases the adaptability to the shafts since it compensates for two types of movement.

[0063] The first bar 40 and the second bar 42 form a first pair 46 of bars 38. The plurality of bars 38 also includes at least one, preferably a second pair 48 of bars identical to the first pair 46. The transmission sphere 44 is a first transmission sphere; the transmission joint 30 further includes a second transmission sphere associated with each second pair 48 of bars 38. Preferably, the second pairs 48 are identical to the first pair 46, and the second spheres are identical to the first sphere. The pairs of bars are angularly distributed around the axis of rotation 32. In the present embodiment, the transmission joint 30 comprises three pairs of bars.

[0064] According to an alternative of the invention, the transmission joint comprises two, four, or any other number of pairs of bars.

[0065] Figure 3 shows a transmission joint 30 for a motor vehicle, exhibiting a first gap. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 2. The bars 38 are parallel. In the present angular orientation of the transmission joint 30, only two pairs are visible.

[0066] In the following description, reference will be made to the first pair of bars 38. However, the characteristics presented also apply to the second pairs of bars; unless otherwise stipulated.

[0067] The first bar 40 is axially distanced from the second bar 42. The first bar 40 and the second bar 42 are symmetrical. They are preferably identical. The first hub 34 and the second hub 36 are symmetrical. They are identical. They are axially distanced from each other.

[0068] The gap 50 of the transmission joint 30 is measured between the first hub 34 and the second hub 36. The transmission joint 30 is extensible along the axial direction; therefore along the axis of rotation 32.

[0069] The bars 38 pass through the first hub 34 and the second hub 36. The first bar 40 includes a first axial stop 52 opposite the transmission sphere 44. The second bar 42 includes a second axial stop 54 opposite the transmission sphere 44. The stops limit the movement of the bars. They can serve as mounting surfaces for springs. The stops are outside the gap 50.

[0070] The first bar 40 includes an outer radius 84. The outer radius 84 may be a medium radius. The first hub 34 includes a disc 56 with a thickness 58 greater than the outer radius 84. The thickness 58 is measured axially. The first bar 40 is slidably mounted within said disc 56, which forms a guide for the first bar 40. The first hub 34 has a mounting surface 60 for attachment to the first shaft. The mounting surface 60 projects onto the disc 56 on the opposite side from the transmission sphere 44. Similarly, the second hub 36 has a mounting surface 60.

[0071] Figure 4 shows a transmission joint 30 for a motor vehicle, according to an embodiment of the invention. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 3.

[0072] The transmission joint 30 has a reduced gap 50 compared to [Fig. 3]. The first hub 34 and the second hub 36 have moved closer together by sliding along the first bar 40 and the second bar 42, respectively. The first hub 34 and the second hub 36 remain coaxial here. The clearance between the first bar 40 and the second bar 42 remains constant.

[0073] According to an alternative embodiment of the invention, the first bar is fixed relative to the first hub. They are axially locked relative to each other. Only the second hub slides on its bars.

[0074] According to another alternative of the invention, the second bar is fixed relative to the second hub.

[0075] According to one embodiment, each bar has a round, square or oval profile.

[0076] Figure 5 shows a transmission joint 30 for a motor vehicle, according to an embodiment of the invention. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 4.

[0077] The transmission joint 30 comprises a first hub 34 fixed to the first shaft 24 (shown in dashed lines), a second hub 36 fixed to the second shaft 26 (shown in dashed lines); a plurality of bars 38 coupling the hubs, distributed around the axis of rotation 32. They are angularly distributed around the axis of rotation 32. The bars 38 extend axially. They are parallel to the axis of rotation 32. Their ends at the transmission sphere 44 are at a distance from the axis of rotation 32.

[0078] A first bar 40 is fixed to the first hub 34 by means of a sliding joint; preferably a sliding pivot joint with two degrees of freedom. A second bar 42 is fixed to the second hub 36 by means of another sliding joint. The first bar 40 is separate from the second bar 42. They are movable relative to each other. They are separated by a transmission sphere 44. The transmission sphere 44 is located at the interface 62 between the first bar 40 and the second bar 42.

[0079] The transmission sphere 44 enters the first bar 40 and the second bar 42 in order to transmit torque from one bar to the other, and thus from one hub to the other. These sliding bars allow for a variation in the inclination of the transmission joint 30, which is accompanied by a variation in length, while the transmission joint 30 rotates around the axis of rotation 32.

[0080] The rotation axis 32 here forms a broken line. It has two segments inclined relative to each other. Each rotation axis segment is coaxial with one of the rotation axes of the first shaft and the second shaft. The first bar 40, the second bar 42, and the transmission sphere 44 are configured such that the second hub 36 can be inclined relative to the first hub 34 by an angle of inclination 64 of at least 5°, preferably at least 10°, and more preferably at least 20°. The axial play between the first bar 40 and the second bar 42 allows the angle of inclination 64 to be increased.

[0081] The angle of inclination 64 is measured between the first bar 40 and the second bar 42 of the first pair 46, or between the first hub 34 and the second hub 36; in particular against their disc 56.

[0082] Figure 6 shows a transmission joint 30 for a motor vehicle, according to an embodiment of the invention. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 5. The transmission joint 30 is more angled than in Figure 5.

[0083] In the first pair 46 of bars, the second bar 42 rotates relative to the first bar 40 around the transmission sphere 44 by the angle of inclination 64. Similarly in the second pairs 48, the bars 38 tilt by the angle of inclination 64 around their second transmission sphere.

[0084] In the first pair 46, the first bar 40, the second bar 42, and the transmission sphere 44 are configured so that the second hub 36 can be tilted relative to the first hub 34 by an angle of inclination 64 of at least 45°, preferably at least 60°. As shown in the present figure, each bar 38 slides relative to its associated hub to compensate for the inclination. Each pair has a different sliding distance. The sliding distances vary cyclically as the hubs rotate around the axis of rotation 32. Thus, the axial translations of the bars 38 compensate for the inclination of the hubs.

[0085] According to one option of the invention, the transmission joint comprises elastic means configured to hold the first bar and the second bar against the transmission sphere. Helical springs may be connected to the hubs.

[0086] According to an alternative of the invention, the transmission joint comprises a cable passing through the transmission sphere and connecting the first bar to the second bar.

[0087] According to an alternative of the invention, the transmission joint includes magnetic means configured to hold the transmission sphere against the first bar and the second bar.

[0088] Figure 7 shows a transmission sphere 44 between a first bar 40 (partially shown) and a second bar 42 (partially shown) of a transmission joint for a motor vehicle, according to an embodiment of the invention. The motor vehicle may correspond to the one shown in relation to one of Figures 1 to 6. The angle of inclination 64 is greater than or equal to 55°.

[0089] The transmission sphere 44 is a coupling ball, suitable for ensuring mechanical coupling. The first bar 40 has a first diameter 66, and the transmission sphere 44 has a second diameter 68 smaller than the first diameter 66. The first diameter 66 is an average diameter. This configuration improves the stability of the transmission sphere 44 in the first bar 40 and the second bar 42; and therefore the mechanical torque transmissible by the transmission joint.

[0090] The first bar 40 includes an outer spoke 84. The first hub includes a disc with a thickness greater than the outer spoke 84. The first hub includes an opening fitted to the outer spoke 84. The first bar 40 is thus mounted in said disc via a sliding connection limiting axial binding. Consequently, the first bar 40 is able to slide within the first hub while ensuring mechanical torque transmission.

[0091] The first bar 40 includes a first cavity 70 opposite the first hub. The second bar 42 includes a second cavity 72 opposite the second hub. The transmission sphere 44 is housed in the first cavity 70 and in the second cavity 72. The cavities form the inlets of the bars.

[0092] The first bar 40 and the second bar 42 are tubular and include cylindrical recesses 74. Each cylindrical recess 74 extends axially along the entire length of its corresponding bar. The cylindrical recesses 74 may terminate at axial stops (not shown). The transmission sphere 44 extends within said cylindrical recesses 74. The depth of penetration of the sphere transmission 44 in the cylindrical recesses 74 increases the stability of the transmission sphere 44 and therefore the transmissible torque.

[0093] According to an alternative of the invention, the first bar is generally solid, and has a pocket with a spherical concave surface which fits the outer surface of the transmission sphere.

[0094] The first bar 40 includes a first circular contact zone 76 against the transmission sphere 44. The second bar 42 includes a second circular contact zone 78 against the transmission sphere 44. The first contact zone 76 and the second contact zone 78 are circular edges, which limits friction.

[0095] The transmission sphere 44 includes an arc 80 housed in the first bar 40. The arc 80 is formed on the outer surface of the transmission sphere 44. The arc 80 is delimited by the first contact zone 76. The arc 80 forms an obtuse angle 82 on the transmission sphere 44. The obtuse angle 82 is at least 91°, preferably at least 100°, more preferably at least 120°, and possibly at least 140°. The width of the obtuse angle 82 increases the stability of the transmission sphere 44. The transmission sphere 44 has an identical arc in the second bar 42.

[0096] According to an alternative embodiment of the invention, each bar comprises a flat end and a plurality of protrusions projecting axially from the flat end. The protrusions are distributed around the flat end in order to cooperate with the transmission sphere.

[0097] According to one embodiment, the transmission sphere is made of metal or ceramic to limit wear.

[0098] According to one embodiment, the transmission sphere is made of a plastic or composite material. The transmission sphere comprises at least 10% by weight of recycled plastic material based on the total weight of the plastic material; preferably from 10 to 80% by weight; more preferably from 20 to 60% by weight or from 30 to 40% by weight. The use of recycled plastic material reduces the vehicle's environmental footprint.

[0099] The invention comprises the combination of all the embodiments illustrated by all the figures.

Claims

Demands

1. A transmission joint (30) for coupling a first shaft (24) to a second shaft (26); the transmission joint (30) comprising: a rotation axis (32), a first hub (34) for connecting to the first shaft (24), a second hub (36) for connecting to the second shaft (26); a plurality of bars (38) about the rotation axis (32) extending axially; characterized in that the plurality of bars (38) comprises a first bar (40) integral with the first hub (34); a second bar (42) integral with the second hub (36); at least one of the first bar (40) and the second bar (42) being capable of sliding axially relative to the first hub (34) or the second hub (36);the transmission joint (30) further comprising a transmission sphere (44) axially engaged in the first bar (40) and in the second bar (42) in order to transmit a torque from the first hub (34) to the second hub (36) via the first bar (40) and the second bar (42).

2. Transmission joint (30) according to claim 1, characterized in that the first bar (40) comprises a first cavity (70) opposite the first hub (34), the second bar (42) comprises a second cavity (72) opposite the second hub (36); the transmission sphere (44) being housed in the first cavity (70) and the second cavity (72).

3. Transmission joint (30) according to any one of claims 1 to 2, characterized in that the transmission sphere (44) comprises an arc (80) housed in the first bar (40), said arc (80) describing an obtuse angle (82); preferably, said obtuse angle (82) is greater than or equal to 120°.

4. Transmission joint (30) according to any one of claims 1 to 3, characterized in that the first bar (40) comprises a first circular contact zone (76) against the transmission sphere (44); and the second bar (42) comprises a second circular contact zone (78) against the transmission sphere (44); preferably, the first contact zone (76) and the second contact zone (78) are circular edges.

5. Transmission joint (30) according to any one of claims 1 to 4, characterized in that the first bar (40) comprises a first axial stop (52) opposite the transmission sphere (44) and / or the second bar (42) includes a second axial stop (54) opposite the transmission sphere (44).

6. Transmission joint (30) according to any one of claims 1 to 5, characterized in that the first bar (40) comprises a first diameter (66), the transmission sphere (44) comprises a second diameter (68) smaller than the first diameter (66).

7. Transmission joint (30) according to any one of claims 1 to 6, characterized in that the first bar (40) comprises an outer spoke (84), the first hub (34) comprises a disc (56) with a thickness (58) greater than the outer spoke (84); preferably, the first bar (40) is mounted in said disc (56) via a sliding connection.

8. Transmission joint (30) according to any one of claims 1 to 7, characterized in that the first bar (40) is at a distance from the second bar (42); preferably, the first bar (40), the second bar (42) and the transmission sphere (44) are configured so that the second hub (36) is tiltable relative to the first hub (34) by an angle of inclination (64) of at least 5°, more preferably of at least 45°.

9. Transmission joint (30) according to any one of claims 1 to 8, characterized in that the first bar (40) and the second bar (42) form a first pair (46) of bars; the plurality of bars (38) also includes second pairs (48) of bars identical to the first pair (46), the transmission sphere (44) is a first transmission sphere; the transmission joint (30) further comprising a second transmission sphere associated with each second pair (48) of bars.

10. Motor vehicle (10) comprising a transmission joint (30); characterized in that the transmission joint (30) conforms to any one of claims 1 to 9; preferably, the motor vehicle (10) comprises a front engine (14), a rear axle comprising: rear wheels (16), a suspension system (18) with leaf springs (28); the rear wheels (16) being coupled to the front engine (14) via said transmission joint (30).

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