Rear axle of electric motor vehicle

Abstract

The invention relates to a rear axle adapted to be installed under the chassis (10) of an electric motor vehicle equipped with an electric accumulator battery (20). Said rear axle comprises: two suspension arms (16, 18) adapted to be articulated on said chassis (10), each of said two suspension arms having a free end (30, 44); two wheel motors (34, 48) mounted respectively on the two free ends (30, 44) of said two suspension arms; two control conduits (82, 84) respectively connected to said two wheel motors (34, 48), said two control conduits being adapted to reach said electric accumulator battery (20) in order to control said two wheel motors; and, the two suspension arms (16, 18) each have longitudinal open recesses to receive the two control conduits (82, 84) respectively. Figure to be published with the abbreviation: Fig. 2

Description

Title of the invention: Rear axle of an electric motor vehicle

[0001] The present invention relates to a rear axle adapted to be installed under the chassis of an electric motor vehicle.

[0002] Known motor vehicle rear axles comprise two suspension arms mounted articulated on the chassis. The two arms extend towards the rear of the chassis and are connected together by means of a cross member.

[0003] Also, they each include at their free end a wheel support and a spring doubled with a shock absorber connected to the chassis.

[0004] Usually, electric motor vehicles have an electric motor located at the front of the vehicle and electric storage batteries installed at the rear or under the chassis of the vehicle to power the motor.

[0005] The motor is then connected to the storage battery by means of electrical power cables of a relatively large cross-section.

[0006] The connection between the motor and the batteries does not pose any difficulty, because they are held in a fixed position relative to each other on the chassis of the vehicle.

[0007] On the other hand, for some electric motor vehicles, wheel motors are used. Thus, electric motors are installed in the two front wheels or in the two rear wheels, or even in all four wheels, which frees up a lot of space in the motor vehicle.

[0008] However, when the vehicle is moving, the wheels are mobile in movement relative to the chassis of the vehicle. And consequently, the electrical power cables which connect each of the wheel motors with the storage battery must have relatively flexible portions to allow this relative movement without being damaged.

[0009] This is particularly the case for the power cables which connect the wheel motors of the two suspension arms of a rear axle of an electric motor vehicle.

[0010] A problem which then arises and which the present invention aims to solve is to provide a rear axle of an electric motor vehicle which makes it possible to preserve the electrical power supply cables which extend from the storage battery to the wheel motors.

[0011] In order to solve this problem, a rear axle is proposed which is suitable for being installed under the chassis of an electric motor vehicle equipped with an electric accumulator battery, said rear axle comprising: two suspension arms suitable for being mounted articulated on said chassis, each of said two suspension arms having a free end; two wheel motors mounted respectively on the two free ends of said two suspension arms; two ducts of control respectively connected to said two wheel motors, said two control conduits being adapted to join said battery of electric accumulators to be able to control said two wheel motors; and, said two suspension arms respectively have open longitudinal recesses to be able to respectively receive said two control conduits inside said open longitudinal recesses.

[0012] Thus, a characteristic of the invention lies in the implementation of arms having recesses to be able to house the control conduits, and in particular the electrical power supply cables. Thus, the control conduits extend in the longitudinal direction of the vehicle and enter the suspension arms at the level of their articulation on the chassis, which arms also extend in said longitudinal direction. The control conduits run inside the arms and are curved as they approach the free end to be able to be connected to the wheel motors. In this way, the control conduits extend longitudinally in the same direction along the chassis, extending into the suspension arms. In this way, the only portion of control conduit which flexes substantially is that which is located astride the articulation.As a result, the control lines experience little flex and are not at risk of damage.

[0013] According to a particularly advantageous embodiment of the invention, each of said two suspension arms is U-shaped and it comprises a first branch having a first end and a second branch having a second end, the first and second ends being adapted to be connected to said chassis.

[0014] In this way, more rigid arms are obtained and it is then possible to avoid connecting them with a cross member. Such a cross member can in fact present a disadvantage when it comes to inserting a battery of accumulators into the chassis.

[0015] Also, and advantageously but in no way limitingly, the first and second branches respectively have first and second open longitudinal recesses. For example, the first and second branches have a U-shaped section, open opposite the chassis. The control conduits are then held inside one of the branches as will be explained below.

[0016] Preferably, the first and second branches are closed by means of a cover.

[0017] According to a particularly advantageous embodiment of the invention, said two control conduits extend respectively inside the first open recesses of the first branches of said two arms. As will be explained in more detail in the remainder of the description, such a characteristic makes it possible to impart a relatively high radius of curvature to the control conduits at level of the free end to join the wheel motors. Thus, despite the rigidity of the control ducts, they are not damaged by the relative curvature.

[0018] Advantageously, the rear axle according to the invention further comprises a torsion bar connecting together the first ends of the first branches, while the second ends of the second branches extend opposite each other with respect to said torsion bar. In other words, the second ends of the second branches extend respectively in the extension of the torsion bar. In this way, the torsion bar makes it possible to maintain the two arms in the same plane to keep a pitch parallel to the surface of the ground.

[0019] Also, according to a preferred embodiment, said torsion bar is adapted to be mounted for rotation in a transverse direction of said chassis, while said second ends of the second branches are adapted to be pivotally mounted on said chassis coaxially with said torsion bar. Thus, the torsion bar is mounted for rotation in supports secured to the chassis, preferably by means of silentbloc®. The second ends of the second branches are mounted for rotation in yokes made of sheet metal and secured to the chassis also by means of silentbloc®. In this way, a perfectly rigid rear axle is obtained, capable of supporting heavy loads.

[0020] Furthermore, said two wheel motors are mounted respectively on said second branches. In other words, they are mounted laterally on the outer branches of the suspension arms.

[0021] In addition, the rear axle according to the invention further comprises, and in a particularly advantageous manner, two spring members mounted respectively on said two U-shaped suspension arms opposite said first and second ends of said branches. The two spring members are preferably helical springs and they extend substantially vertically between a lower end secured to the suspension arm and an upper end secured to the chassis. In addition, the rear axle is also advantageously equipped with two shock absorbers connecting the arms and the chassis and extending inside the springs. In this way, the compactness of the actual damping function is improved.

[0022] Also, and according to a particularly advantageous embodiment, the rear axle further comprises cooling pipes for said wheel motors extending respectively inside said two suspension arms. Preferably, the cooling pipes extend longitudinally along the chassis and then in the second branches of the arms. They then open directly at the wheel motors and allow the braking elements to be cooled.

[0023] Furthermore, said two control conduits respectively comprise two electrical power supply cables. It has a relatively large cross-section to be able to supply the wheel motors.

[0024] Other features and advantages of the invention will emerge from reading the description given below of a particular embodiment of the invention, given for informational purposes but not as a limitation, with reference to the appended drawings in which:

[0025] [Fig.l] is a partial schematic perspective view from above of an electric motor vehicle chassis including a rear axle according to the invention;

[0026] [Fig.2] is a partial schematic perspective view from below of the object of the [Fig.l];

[0027] [Fig.3] is a schematic perspective view from above of the rear axle according to the invention;

[0028] [Fig.4] is a schematic sectional view of the object of [Fig.3] according to plane IV- IV; and,

[0029] [Fig.5] is a schematic sectional view of the object of [Fig.3] along plane VV.

[0030] [Fig.l] partially shows an electric motor vehicle chassis 10, having a front part 12 opposite a rear part 14.

[0031] It is inscribed in an orthogonal reference frame X, Y, Z, in which the X axis extends in a longitudinal front-rear 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] Thus, towards the rear part 14, the chassis comprises a rear axle 15. And the rear axle 15 comprises two suspension arms, a right suspension arm 16 and an opposite left suspension arm 18. And towards the front part 12, the chassis 10 is equipped with a battery of accumulators 20.

[0033] We will refer to [Fig. 3] in order to describe in detail the rear axle 15. We find the two suspension arms, right 16 and left 18. Also, we will observe that the suspension arms 16, 18 are U-shaped.

[0034] Thus, the right arm 16 comprises a right inner branch 22 and a right outer branch 24. The right inner branch 22 has a right inner end 26, while the right outer branch 24 has a right outer end 28.

[0035] The straight branches 22, 24 extend parallel to each other in a mean plane and they meet opposite their ends 26, 28.

[0036] Also, the right arm 16 has a right free end 30 in the extension of the two branches 22, 24. This right free end 30 is formed in a spatula and it accommodates a right helical spring 32.

[0037] Also, the right arm 16 has at its free right end 30, a right wheel motor 34, flanked in the extension of the right outer branch 24.

[0038] Conversely, the left arm 18 comprises a left inner branch 36 and a left outer branch 38. The first has a left inner end 40, while the second has a left outer end 42.

[0039] The left branches 36, 38 extend parallel to each other in a mean plane and they join opposite their ends 40, 42.

[0040] Furthermore, the left arm 18 has a left free end 44 in the extension of the two left branches 36, 38. And this left free end 44 is formed in a spatula symmetrically with respect to the right free end 30. The left free end 44 accommodates a left helical spring 46.

[0041] And also, the left arm 18 has at its left free end 44, a left wheel motor 48, flanked in the extension of the left outer branch 38. Thus, the left wheel motor 48 extends opposite the right wheel motor 34.

[0042] Also, the two suspension arms 16, 18 are rigidly connected together by means of a torsion bar 50. The torsion bar 50 precisely connects the right inner end 26 and the left inner end 40, respectively, of the right inner 22 and left inner 36 branches.

[0043] The two opposite ends of the torsion bar 50 are thus mounted in engagement in the right inner end 26 and left end 40, so that the right inner branch 22 and left inner branch 36 are kept parallel to each other.

[0044] In other words, the torsion bar 50, when at rest, makes it possible to maintain the right 22 and left 36 inner branches as well as the right 24 and left 38 outer branches substantially in the same plane.

[0045] Also, the torsion bar 50 is rotatably mounted in a right bearing 52, located near the right inner branch 22, and in a left bearing 54 located near the left inner branch 36.

[0046] Furthermore, the right outer end 28 and the left outer end 42 are respectively rotatably mounted in a right angle member 56 and in a left angle member 58.

[0047] The right 52 and left 54 ​​bearings, on the one hand, and the right 56 ​​and left 58 angle member make it possible to keep the rear axle 15 mobile in pivoting under the chassis 10 along a transverse axis. We will now refer to [Fig.2] on which we find these elements seen from below.

[0048] Thus, we find in this [Fig.2], the right suspension arm 16 opposite the left suspension arm 18. The right 52 and left 54 ​​bearings are mounted in a fixed position on a rear cross member 60 of the chassis 10, so that the torsion bar 50 is oriented in a transverse direction of the chassis 10. Also, the right 56 ​​and left 58 corner members are mounted under the chassis.

[0049] Also, we find the right inner branch 22 and the right outer branch 24 of the right suspension arm 16 on the one hand, and the left inner branch 36 and the left outer branch 38 of the left suspension arm 18 on the other hand.

[0050] In addition, the right wheel motor 34 is provided with a right wheel 66, while the left wheel motor 48 is provided with a left wheel 68.

[0051] Furthermore, the right inner 22 and right outer 24 branches of the right suspension arm 16, and the left inner 36 and left outer 38 branches of the left suspension arm 18, have a U-shaped cross-section.

[0052] In this way, the right inner branch 22 has a right inner longitudinal recess 70, the right outer branch 24 has a right outer longitudinal recess 72, the left inner branch 36 has a left inner longitudinal recess 74, and the left outer branch 38 has a left outer longitudinal recess 76. These longitudinal recesses 70, 72, 74 and 76 open out opposite the chassis 10. In other words, they open out facing the ground.

[0053] In addition, the right inner 70 and right outer 72 longitudinal recesses converge towards each other and join in a right curved portion 78 towards the right free end 30. Similarly, the left inner 74 and left outer 76 longitudinal recesses also converge towards each other by joining in a left curved portion 80.

[0054] Thus, the wheel motors 34, 48 are supplied with electrical energy respectively, by two control conduits, 82, 84, extending respectively into the right 70 and left 74 internal longitudinal recesses.

[0055] The control conduits 82, 84 comprise electrical power supply cables. They extend longitudinally from the storage battery 20 to the right 26 and left 40 inner ends, then they are guided longitudinally respectively inside the right 70 and left 74 inner longitudinal recesses of the right 22 and left 36 inner branches respectively.

[0056] Then, the control conduits 82, 84 are curved and run respectively in the right curved portion 78 and the left curved portion 80 to then open laterally from the right 22 and left 36 inner branches respectively to join the wheel motors 34, 48.

[0057] In this way, the control conduits 82, 84, which are relatively rigid, are held in a fixed position according to a relatively large radius of curvature inside the inner branches 22 and 36 and the curved portions 78, 80 to reach the wheel motors 34, 48.

[0058] The control conduits 82, 84 are thus protected from the outside and they undergo little deformation despite the relative movement of the suspension arms 16, 18 relative to the chassis 10.

[0059] Refer to [Fig.4] showing in longitudinal and vertical section along plane IV - IV illustrated in [Fig.3], the left inner branch 36 and the left control duct 84. Thus, it is understood that the left arm 18 will be able to pivot relative to the chassis 10 around the axis defined by the torsion bar 50 and consequently, that the left control duct 84 will be able to deform substantially without being altered. Indeed, its maximum radius of curvature will remain very large.

[0060] Furthermore, the wheel motors 34, 48 are equipped with braking systems not shown. And these braking systems heat up when they are in operation. Also, heat exchangers are installed on the braking systems and they are supplied by right 86 and left 88 cooling ducts running respectively inside the right 72 and left 76 external longitudinal recesses.

[0061] In this way, these cooling ducts 86, 88 are protected despite relative movements of the suspension arms 16, 18 relative to the chassis 10.

[0062] As illustrated in [Fig.5] then showing in longitudinal and vertical section along the plane V - V illustrated in [Fig.3], the left outer branch 38 and the left cooling duct 88, when the left arm 18 pivots relative to the chassis 10 around the axis of the torsion bar 50, the left cooling duct 88 can deform significantly without being altered. Because in fact, its maximum radius of curvature will also remain very large.

Claims

Claims

1. Rear axle (15) adapted to be installed under the chassis (10) of an electric motor vehicle equipped with an electric storage battery (20), said rear axle comprising: - two suspension arms (16, 18) adapted to be mounted articulated on said chassis (10), each of said two suspension arms having a free end (30, 44); - two wheel motors (34, 48) mounted respectively on the two free ends (30, 44) of said two suspension arms; - two control conduits (82, 84) respectively connected to said two wheel motors (34, 48), said two control conduits being adapted to join said electric storage battery (20) to be able to control said two wheel motors;characterized in that said two suspension arms (16, 18) respectively have open longitudinal recesses to be able to respectively receive said two control conduits (82, 84) inside said longitudinal recesses.;

2. Rear axle according to claim 1, characterized in that each of said two suspension arms (16, 18) is U-shaped and it comprises a first branch (22; 36) having a first end (26; 40) and a second branch (24; 38) having a second end (28; 42), the first and second ends being adapted to be connected to said chassis (10).

3. Rear axle according to claim 2, characterized in that the first (22; 36) and second (24; 38) branches respectively have first (70; 74) and second (72; 76) open longitudinal recesses.

4. Rear axle according to claim 3, characterized in that said two control conduits (82, 84) extend respectively inside the first open recesses (70; 74) of the first branches (22, 36) of said two arms (16, 18).

5. Rear axle according to any one of claims 2 to 4, characterized in that it further comprises a torsion bar (50) connecting together the first ends (26, 40) of the first branches (22, 36), while the second ends (28, 42) of the second branches (24, 38) extend opposite each other with respect to said torsion bar (50).

6. Rear axle according to claim 5, characterized in that said torsion bar (50) is adapted to be mounted for rotation in a transverse direction of said chassis (20), while said second ends (28, 42) of the second branches (24, 38) are adapted to be mounted for pivoting on said chassis (10) coaxially with said torsion bar (50).

7. Rear axle according to any one of claims 2 to 6, characterized in that said two wheel motors (34, 48) are mounted respectively on said second branches (24, 38).

8. Rear axle according to any one of claims 2 to 7, characterized in that it further comprises two spring members (32, 46) mounted respectively on said two suspension arms (16, 18) formed in a U opposite said first (26; 40) and second (28; 42) ends of said branches (22, 36, 24, 38).

9. Rear axle according to any one of claims 1 to 8, characterized in that it further comprises cooling pipes (86, 88) for said wheel motors (34, 48) extending respectively inside said two suspension arms (16, 18).

10. Rear axle according to any one of claims 1 to 9, characterized in that said two control conduits (82, 84) respectively comprise two electrical power supply cables.

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