Improved axle / beam of electric tractor

Abstract

The invention relates to an improved axle / beam of an electric tractor. The electric drive axle, namely the electric axle / electric beam (1), is used for a vehicle. An electric vehicle axle / electric beam (1) comprising a housing (C) defining a space (V) separated from the external environment and at least one electric machine (2) and a pair of drive shafts (4 ', 4' ') each connected to a respective wheel of the vehicle and supported by the housing (C), the electric vehicle axle (1) comprising a transmission chain housed in the space (V), the invention relates to a drivetrain operatively connecting at least one electric machine (2) to a pair of drive shafts (4 ', 4' '), the drivetrain comprising a first transmission system (5) operatively interposed in series between the at least one electric machine (2) and the pair of drive shafts (4', 4 ''), a speed shift system (6), a second transmission system (7) and a differential assembly (8), where the speed shift system (6) comprises a clutch shift system (60).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the priority of Italian patent application no. 102023000021981 filed on October 20, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to vehicle axles / beams.

[0004] A preferred, but not exclusive, application of the invention is an electric traction vehicle axle / beam, a so-called "e-axle" or "e-beam". Reference will be made to this application by way of example below. Background Art

[0005] As is known, there is an increasing need to reduce polluting emissions caused by internal combustion engines used to operate vehicles, in particular for achieving traction of the vehicles.

[0006] This need is even greater for light commercial vehicles (LCV), medium commercial vehicles (MCV) or heavy commercial vehicles (HCV) such as trucks and motor vehicles in general.

[0007] For this purpose, there are known solutions: electric axles or electric beams, i.e. electric traction axles or electric beams, wherein the axle / beam supports one or more electric machines configured to exchange torque with the drive shaft of the axle and therefore with the wheels, in order to provide or generate power depending on the use of the vehicle.

[0008] More specifically, it should be noted that the axle is the only component connecting the two hubs that performs a support function, while the beam is the component connecting the two hubs but where the drive shaft and differential assembly are also present as well as the input point for tractive torque.

[0009] Examples of these electric axles are shown in patents US2022 / 0250457A1, US2020 / 0282827A1 and US2022 / 0065334A1.

[0010] These solutions involve using the electric machine in a so-called “coaxial” configuration, in other words, in which the axis of the electric machine is coaxial with the axis of the axle / beam drive shaft.

[0011] Although this configuration is advantageous with regard to the direct assembly of the element on the axle itself, it is particularly disadvantageous with regard to the dimensions in the axial direction.

[0012] In fact, the positioning of the particularly bulky electric motor limits the positioning of other functional elements unless the longitudinal dimension of the axle is increased.

[0013] Since this extension is not always possible due to the size of the components already present on the axle (suspension, brake system components, frame components, axle track limiters, etc.), the transmission connecting the motor to the wheel or the motor itself must be resized, effectively reducing the power and performance available to the axle or beam.

[0014] As a result, the versatility of providing torque and power over extended intervals, which is an essential feature for providing an electric axle or electric beam that can be used under different vehicle operating conditions, is compromised.

[0015] Therefore, there is a need to provide an electric axle or electric beam which can have a reduced size while maintaining as extended an operating range as possible in terms of torque and power to meet various vehicle operating conditions.

[0016] The object of the present invention is to meet the needs outlined above in an optimal and inexpensive manner. Summary of the invention

[0017] The above objects are achieved by the electric traction vehicle axle / beam as claimed in the various aspects of the invention which are an integral part of the present description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a better understanding of the present invention, preferred embodiments are described below by way of non-limiting examples and with reference to the accompanying drawings, in which:

[0019] · Figure 1 is a diagram indicating the operational relationship between various functional systems of an electric traction vehicle axle / beam according to a first embodiment of the present invention;

[0020] · Figure 2 is a schematic diagram of an electric traction vehicle axle / beam according to a first embodiment of the present invention;

[0021] · Figure 3 is a schematic diagram of an electric traction vehicle axle / beam according to a second embodiment of the present invention; and Figure 4 is a schematic diagram of a cross section of an electrically driven axle according to a first embodiment of the present invention. DETAILED DESCRIPTION

[0022] For simplicity, the expressions axle / beam or electric axle / electric beam will be used below to avoid repetition, since the invention can be applied to both architectures.

[0023] Figure 1Schematically depicted is a drive train for exchanging torque in an electric axle / beam 1 or electric axle / electric beam between an electric motor 2 and a pair of wheels 3 supported by a drive shaft 4', 4" of the electric axle 1 according to a first embodiment of the invention.

[0024] As is known, the motor 2 is electrically connected to a power source, such as a battery pack of the vehicle (not shown), and is configured to exchange power with the power source, in particular to receive power to generate torque for the wheels 3 or to receive torque from the wheels 3 to introduce power into the motor.

[0025] As schematically depicted, the drive train of the electric axle 1 sequentially includes a first transmission system 5 , a second transmission system 7 , and a differential assembly 8 between the motor 2 and the wheels 3 .

[0026] Advantageously, there is also a speed ratio shifting system 6 between the first transmission system 5 and the second transmission system 7. The term "transmission system" refers to a system for changing the torque / speed between input and output, the ratio of the transmission system to the output or input being greater than 1, less than 1 or equal to 1. Advantageously, the second transmission system 7 is designed as a speed reducer.

[0027] A differential assembly 8 is interposed between the drive shafts 4 ′, 4 ″. Optionally, the drive shafts 4 ′, 4 ″ may be connected to wheels by means of a wheel hub transmission system 9 , respectively.

[0028] Optionally, there may be a differential locking system 11 disposed between the differential assembly 8 and one of the drive shafts 4', 4", and as an additional option, there may be a parking brake system 12 configured to operatively cooperate with the second transmission system 7 or the differential assembly 8 to lock the movement of the electric axle 1.

[0029] Likewise, optionally, there may be an oil distribution system 13 operatively interposed between the differential assembly 8 and one of the drive shafts 4 ′, 4 ″ and the corresponding wheel hub transfer system 9 .

[0030] There may also be an optional disconnect system between the wheels 6 and the differential assembly 8, which connects or disconnects one of the two drive shafts by actually disconnecting at least one motor 2 from the drive chain upstream of the differential assembly 8, thereby making vehicle traction possible.

[0031] Reference Figure 2 It should be noted that the operating shaft 2' of the motor 2, i.e. the axis of the shaft supported by the rotor of the motor 2, is coaxial with the axis B, which is parallel to the longitudinal axis A of the axle / beam 1, i.e. the longitudinal axis A coaxial with the drive shaft 4', 4", and is spaced apart from the longitudinal axis A.

[0032] For the sake of simplicity, this configuration in which the axes A, B are separated and parallel will be defined as an "off-axis configuration" below.

[0033] Although only partially included in Figure 4 In the embodiment of the present invention, the axle 1 comprises a housing C designed to house the described transmission chain, a part of the drive shaft 4', 4", and to support the motor 2, in particular the stator of the motor 2. The housing C defines a space V designed to house the following elements of the transmission chain, thereby isolating these elements from the external environment.

[0034] An operating shaft 2 ′ of the electric machine 2 is operatively connected to the input shaft 15 by means of a first transmission system 5 .

[0035] Advantageously, the input shaft 15 is supported so as to rotate freely relative to one of the two drive shafts 4', 4"; for simplicity, in this description reference will be made to the left drive shaft 4', but it is clear that what is described can be exchanged in a mirror-like manner between the left and right drive shafts.

[0036] Advantageously, the first transmission system 5 defines at least one transmission ratio between the input shaft 15 and the operating shaft 2' and is preferably manufactured as a parallel shaft transmission system. Specifically, in an embodiment, the transmission ratio is defined by two speed jumps 5', 5", which are defined by corresponding gear mechanisms.

[0037] In particular, the transmission system includes: a first gear mechanism 5', which is defined by a first toothed gear 5a rigidly supported by the operating shaft 2' and a second toothed gear 5b rigidly supported by the supporting shaft 16; and a second gear mechanism 5", which includes a third toothed gear 5c rigidly supported by the supporting shaft 16 and a fourth toothed gear 5d rigidly supported by the input shaft 15.

[0038] Clearly, although not illustrated, additional gear configurations may be applied, such as, for example, a configuration in which the second toothed gear 5c is not included and the first toothed gear 5a is directly meshed with the second toothed gear 5b and the second toothed gear 5b is directly meshed with the fourth toothed gear 5d, as is implemented, for example, in some embodiments described below.

[0039] In this embodiment, the second transmission system 7 is advantageously made as a compound epicyclic gear, namely a first 7' and a second 7a' sun gear, a plurality of first 7" and second 7a" planetary gears and a crown 7'" connected to the housing.

[0040] The multiple first planetary gears 7" and the multiple second planetary gears 7a" are meshed with the first sun gear 7' and the second sun gear 7a' respectively, and one of the multiple first planetary gears 7" and the multiple second planetary gears 7a" is meshed with the crown 7"', in particular, the multiple second planetary gears 7a" are meshed with the crown 7"'. On the contrary, the rotation of the multiple first planetary gears 7" and the multiple second planetary gears 7a" is integrated, and then the two multiple planetary gears are supported by the same carrier 7a.

[0041] As described below, specifically, the speed shift system 6 is configured to connect one of the sun gears 7 ′, 7 a ′ to the input shaft 15 .

[0042] The differential assembly 8 is of the type with bevel gears and, as is known, comprises a plurality of planetary gears 8' driven by the carrier 7a and meshing with a pair of bevel wheels 8a, 8b rigidly supported by the left 4' and right 4" drive shafts.

[0043] As is known, the differential locking system 11 is configured to lock the action of the differential assembly 8, thereby securely connecting the two drive shafts 4', 4" by connecting one of the two drive shafts 4', 4" with the differential assembly receptacle.

[0044] In the illustrated embodiment, the differential locking system 11 essentially comprises a sleeve 11 b supported so as to slide along the axis A from the hub 11 a and therefore from the right drive shaft 4 ″ by means of a connection, such as a grooved connection, which can be moved due to the action of actuator means not illustrated.

[0045] The sleeve 11 b also defines a toothing 11 c configured to selectively cooperate, according to its movement along the axis A, with a toothing formed on a portion 17 integral with the carrier 7 a .

[0046] The hub transmission system 9 , if present, can be manufactured in different ways as required and in different ways, and therefore, for the sake of brevity, will not be described further.

[0047] Similarly, the parking brake system 12 may be manufactured in different forms and on different operating portions of the axle / beam 1 and therefore will not be described further for the sake of brevity.

[0048] In particular, the lubrication system 13 is interposed between / in conjunction with one of the drive shafts 4 ′, 4 ″ and is configured to provide lubrication fluid to the above-mentioned reduction systems 5 , 7 , the shift assembly 6 , and the differential assembly 8 .

[0049] The lubrication system 13 is thus interposed between / in conjunction with the drive shafts 4', 4" surrounded by the reduction systems 5, 7 and the shift assembly 6, and is therefore located between the differential assembly 8 and the left drive shaft 4' in the described embodiment.

[0050] In particular, it should be noted that the left drive shaft 4' comprises a first portion 4a and a second shaft portion 4b, which are connected to a hub transmission system (if included), which is rigidly connected between the first portion 4a and the second shaft portion 4b; in particular, the bevel wheel 8a is supported by the first portion 4a.

[0051] In particular, the lubrication system 13 is integrated into the first portion 4a, ie is interposed in turn between the differential assembly 8 and the first portion 4a of the drive shaft 4'.

[0052] Advantageously, the lubrication system comprises at least one lubrication duct 20 formed inside the first portion 4a.

[0053] Specifically, in the illustrated embodiment, the lubrication tube 20 includes a first branch 20' fluidly connected to one (or more) lubrication fluid sources F, such as a fluid rotation joint formed in the housing C, and a second branch 20" connected to the first branch 20'.

[0054] Specifically, the second branch 20" extends parallel to the axis A and therefore coaxially with the axis A, and the second branch 20" is open at one end at the end of the first part 4a and therefore inside the differential assembly 8. On the contrary, the first branch 20' extends radially, advantageously perpendicularly, relative to the second branch 20" on the side opposite to the open end of the differential assembly 8.

[0055] The lubrication system 20 further comprises a plurality of lubrication branches 21 extending radially from the second branch 20 ″ and spaced apart from one another along the longitudinal axis A and defining respective lubrication points for the first and second transmission systems 5 , 7 and the gearshift assembly 6 .

[0056] In other words, the lubrication branch 21 is open at one of their first ends and faces the first 5 and second 7 transmission systems and the gearshift assembly (if present), while at the other end the lubrication branch 21 is connected to the second branch 20".

[0057] In the embodiment described, the lubrication branches 21 are formed on the same side of the first branch 20' and all are substantially coplanar. In any case, it is clear that the lubrication branches 21 may be positioned angularly offset circumferentially around the axis A and in a number different from that illustrated.

[0058] Advantageously, the second branch 20 ″ or the lubrication branch 21 may comprise calibrated nozzles, for example at their ends, configured to better dose the lubricant and direct it towards the components to which they are directed.

[0059] In particular, it should be noted that these calibrated nozzles can have different sizes and similarly, the through cross-section of the second branch 20 ″ or the lubrication branch 21 can have different sizes or can vary to provide different flows of lubrication fluid to the different elements they face.

[0060] In particular, the second branch 20 ′ or lubricating branch 21 has a through cross section that is preferably cylindrical or conical in order to pressurize the components with the oil, even by axial force, according to the centrifugal effect triggered by the rotation of the drive shaft 4 ′.

[0061] Advantageously, the second sun gear 7a' defines a through-duct 22 configured to enable the passage of oil through the associated components.

[0062] Advantageously, the speed-shifting system 6 comprises a clutch system 60 configured to selectively connect one of the elements of the second transmission system 7 , in particular one of the two sun gears 7 ′, 7 a ′ in the example described, to the input shaft 15 .

[0063] Advantageously, the clutch system 60 is an oil bath clutch system, and in particular, but without limitation, the clutch system 60 is a multi-plate clutch system.

[0064] In the depicted embodiment, the clutch system 60 may have a Figure 4 The rotating chamber 61 with construction details shown in FIG. Figure 2 ), or a fixed chamber 61 ( Figure 3 ) and a system in which the piston is disengaged from rotation by means of corresponding rolling bearings.

[0065] For the sake of brevity, the following describes Figure 2 and Figure 4 Implementation method in .

[0066] Advantageously, the clutch system 60 comprises a chamber 61 rigidly supported by the input shaft 15 and first and second connecting parts 62 and 63 (referred to in technical terms as outer bell and inner hub) rigidly connected to the first and second sun gears 7 ′ and 7 a ′ respectively.

[0067] The chamber 61 defines a first actuation chamber 64 and a second actuation chamber 65 configured to slidably accommodate pistons 66, 67. In particular, each actuation chamber 64, 65 internally accommodates elastic means 68, 69, such as (advantageously) a cup spring, which are configured to maintain the pistons 66, 67 in a predetermined condition as defined below.

[0068] The chamber 61 also defines a hub 61 ' configured to house pressure plates 66', 67' configured to cooperate in contact with disks 62', 63' respectively integral with the first and second support elements 62, 63.

[0069] Advantageously, the first actuation chamber 64 and the second actuation chamber 65 are fluidically separated, such as the movement of the pistons 66 , 67 and the corresponding pressure plates 66 ′, 67 ′ on the hub 61 ′ and the action of the elastic means 68 , 69 .

[0070] The axle / beam 1 advantageously comprises a hydraulic actuation system 70 to control the clutch system 60. Advantageously, this hydraulic actuation system 70 is incorporated into the input shaft 15.

[0071] Advantageously, the hydraulic actuation system 70 comprises at least one pair of actuation ducts 71 , 72 formed inside the input shaft 15 and configured to be fluidically connected to the first chamber 64 and to the second chamber 65 , respectively.

[0072] In particular, the first and second actuation conduits 71 and 72 are configured to pressurize the first and second chambers 64 and 65 , respectively, by controlling the movement of pistons 66 , 67 accommodated in the first and second chambers 64 , 65 .

[0073] Specifically, in the illustrated embodiment, the actuating conduits 71, 72 are fluidly connected to two sources G, G' of pressurized operating fluid, and in the illustrated embodiment, are respectively and differently connected to two sources G, G' of pressurized operating fluid, such as a fluid rotation joint formed in the shell C.

[0074] According to the above-described embodiment of the present invention ( Figure 2 and Figure 4 )'s electric traction axle / beam embodiment operates as follows.

[0075] In a first operating condition in which the electric machine 2 is used as an electric motor, the electric machine 2 provides a torque to the first transmission system 5, which transmits the torque to the input shaft 15 by increasing the value of the torque and thus reducing the rotational speed. Depending on the actuation of a specific piston 66, 67 against the discs 62', 63', the torque is transmitted from the hub 61' to the first sun gear 7' or the second sun gear 7a'. From there, the torque is transmitted to the planetary gears 7", 7a", and therefore to the carrier 7a. Thereby, the torque is transmitted to the differential assembly 8, where, as is known, the torque is distributed between the drive shafts 4', 4", and therefore transmitted to the wheel 3 by means of the wheel hub reduction system 9 (if included) or directly to the wheel 3.

[0076] If not actuated by the fluid passing from the actuation system 70 , the elastic means 68 , 69 keep the pistons in their rest state, ie a state in which they do not press the respective secondary disk 66 ′, 67 ′ against the disk 62 ′, 63 ′.

[0077] The differential assembly can be locked by means of a differential locking system 11 .

[0078] In a second operating configuration in which the motor 2 acts as a generator, torque is provided by wheels 3 driven by the movement of the vehicle and in the opposite direction following the same drive train previously described to the motor 2 which thus generates electricity from the torque received as input.

[0079] Figure 3 The structure and operation of the embodiment in are similar to the above-described embodiments, in particular the actuation system is simplified because it passes directly through the housing instead of the input wheel 15.

[0080] In summary, the advantages of the electrically driven axle according to the present invention are obvious.

[0081] Thanks to the proposed axle 1 , it is possible to provide an electric axle / electric beam having a reduced longitudinal dimension, while also maintaining a high level of torque / power that can be transmitted by the electrified transmission.

[0082] In particular, due to the proposed transmission system, a high transmission ratio can be provided between the electric machine and the wheel hub in a longitudinally and radially compact manner with respect to the axis of the drive shaft.

[0083] Likewise, the off-axis configuration makes it possible to comfortably house the motor outside the space V containing the transmission elements, thus facilitating their assembly and lubrication.

[0084] In particular, the clutch speed shift system makes it possible to obtain very comfortable gear shifts in a compact manner, since the power shift logic can be set between the pistons, i.e. making it possible to connect one piston while the other is disconnected, and vice versa, without interrupting the flow of drive torque to the wheels when shifting from one gear to another.

[0085] The use of two clutch assemblies therefore makes it possible to transmit such a power shift torque between one gear and another, or to always maintain a given level of drive torque relative to the wheels even during a gearshift maneuver. This function is achieved by controlling the two clutches simultaneously, with one clutch being closed and the other clutch being opened at the same time, or alternatively vice versa.

[0086] The particular arrangement of piston and actuating chamber being coaxial and radially one inside the other is also very compact in the axial direction.

[0087] Likewise, actuation by means of an actuation system integrated into the shaft of the transmission system is particularly cost-effective since it reduces the need for dedicated pipes.

[0088] In particular, since the actuation system is incorporated into one of the lubrication system drive shafts, it is possible to provide a system which adapts itself to the rotational speed of the drive shaft and also utilizes the effect of the centrifugal force generated with the rotation.

[0089] Likewise, multiple lubrication points can be provided without exposing complex, bulky piping to potential damage and breakage.

[0090] Due to good lubrication, the wear on the transmission elements can again be reduced and their fatigue life can therefore be increased, so that losses due to friction and losses due to wasted oil can also be reduced by means of reduced, targeted lubrication, thereby increasing the overall efficiency of the transmission system.

[0091] Additionally, the lubrication provided is additionally effective for the clutch speed shifting system by spraying the plates with sufficient lubricating fluid during all conditions that produce relative speed between the conducting and conducted plates of the two clutch assemblies.

[0092] Finally, it is clear that modifications and variations may be made to the electrically driven axle made according to the invention without departing from the scope of protection defined by the claims.

[0093] Clearly, the described epicyclic mechanism and differential assembly may be assembled or arranged differently than what has been described, such as having other gears and selectors.

[0094] Alternatively, the shift system can be made with dog clutches, radial clutches (with grooves), clutch elements or synchronizer elements as described above. In particular, a dry clutch (isolated from the transmission lubricating fluid) can be used, or advantageously a multi-plate oil bath clutch with "power shift" control can be used.

[0095] Similarly, the actuator and hub transmission system can be manufactured in different ways.

[0096] In particular, the actuator element can be manufactured in various ways, i.e., for example by means of: a piston, a drum, an electric actuator linkage using air or oil, an electromagnetic actuator linkage, a coaxial actuator linkage, or a remote actuator linkage with stable or monostable control, a rotary actuator linkage or a linear actuator linkage, etc.

[0097] Likewise, it is clear that the illustrated embodiments can be combined as long as they are mechanically compatible.

Claims

1. An electrically driven axle for a vehicle, i.e. an electric axle / electric beam (1), comprising a housing (C) defining a space (V) isolated from the external environment and at least one electric motor (2) and a pair of drive shafts (4', 4"), each of which is connected to a respective wheel and supported by the housing (C), The electric axle (1) comprises a transmission chain housed in the space (V), the transmission chain operatively connecting the at least one electric motor (2) to a pair of drive shafts (4', 4"). The transmission chain includes a first transmission system (5), a speed shift system (6), a second transmission system (7) and a differential assembly (8) operatively interposed in series between the at least one motor (2) and a pair of drive shafts (4', 4"). in, The electric motor (2) drives an operating shaft (2'), which is operatively connected to an input shaft (15) by the first transmission system (5), which is carried in a freely rotatable manner by one of the drive shafts (4', 4") and is operatively connected to the second transmission system (7) via the gear ratio shifting system (6), the first transmission system (5) defining at least one speed jump (5', 5") between the operating shaft (2') and the input shaft (15), The speed shifting system (6) comprises a clutch shifting system (60), and the axle comprises: A fluid actuation system (70) for the clutch system (60), the fluid actuation system (70) being incorporated into the input shaft (15).

2. The electric axle / electric beam according to claim 1, wherein: The clutch shifting system (60) comprises a chamber (61) rotatably carried by an element of the first transmission system (5).

3. The electric axle / electric beam according to claim 1, wherein: The clutch shift system (60) includes a chamber (61) fixedly carried by the housing (C).

4. The electric axle / electric beam according to claim 1, wherein: The chamber (61) is carried by the input shaft (15).

5. The electric axle / electric beam according to claim 1, wherein: The second transmission system (7) has epicyclic gears, and the speed shift system (6) is configured to allow torque to be input to the second transmission system (7) through selectively different elements of the transmission system (7).

6. The electric axle / electric beam according to claim 5, wherein: The second transmission system (7) has a compound epicyclic gear, which includes a first sun gear (7') and a second sun gear (7a'), a crown (7'" connected to the ground, and a plurality of first planetary gears (7") and a plurality of second planetary gears (7a"), the plurality of first planetary gears (7") and the plurality of second planetary gears (7a") being meshed between the corresponding sun gears (7', 7a') and the crown (7'") and connected by a common carrier (7a), the planetary gears (7a") and the planetary gears (7") being connected to each other and supported on the carrier (7a) operatively connected to the differential assembly (8), and the gear system (6) selectively connects one of the first sun gear (7') and the second sun gear (7a') to the input shaft (15).

7. The electric axle / electric beam according to claim 1, wherein: The chamber (61) and the hub (61') define a first actuation chamber (64) and a second actuation chamber (65), a first piston (66) and a second piston (67) accommodated in a respective one of the first actuation chamber (64) and the second actuation chamber (65), and a pair of secondary plates (66', 67') movable relative to the hub (61'), the clutch system (60) comprising a plurality of first plates (62') and a plurality of second plates (63') carried by respective supporting elements (62, 63), the respective supporting elements (62, 63) being carried by respective different elements of the second reduction system (7), the plurality of first plates (62') and the plurality of second plates (63') being capable of being connected to the hub (61') by friction through the contact action of the secondary plates (66', 67').

8. The electric axle / electric beam according to claim 7, wherein: The fluid actuation system (70) includes a first actuation conduit (71) and a second actuation conduit (72), wherein the first actuation conduit (71) and the second actuation conduit (72) are configured to fluidly connect respective sources (G and G') of operating fluid under pressure in the first actuation chamber (64) and the second actuation chamber (65).

9. The electric axle / electric beam according to claim 7, wherein: The first actuation chamber (64) and the second actuation chamber (65) are fluidly separated from each other.

10. The electric axle / beam according to claim 1, comprising a lubrication system (13) for the transmission chain, the lubrication system (13) being interposed in series with one of the drive shafts (4', 4").

11. Electric axle / electric beam according to claim 10, the lubrication system (13) being integrated into one of the drive shafts (4', 4").

12. The electric axle / electric beam according to claim 1, wherein: The differential assembly (8) comprises a plurality of planetary gears (8') which are driven by the second transmission system (7) and mesh with a first bevel wheel (8a) and a second bevel wheel (8b) carried by respective drive shafts (4', 4").

13. The electric axle of claim 1, comprising a differential locking system (11) configured to inhibit the function of the differential assembly (8).

14. The electric axle / electric beam according to claim 1, further comprising an optional wheel hub transmission system (9) operatively interposed between each wheel (3) and the corresponding drive shaft (4', 4").

15. The electric axle / electric beam according to claim 1 further includes a parking brake system (12), which is configured to operatively cooperate with at least one of the second transmission system (7) or the differential assembly (8) to block the movement of the electric axle / electric beam (1).

16. Electric axle / electric beam according to claim 1, comprising a system for disconnecting the drive shaft (4', 4").

17. A vehicle comprising the electric axle / electric beam according to claim 1.

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