ELECTRIC AXLE FOR INDUSTRIAL OR COMMERCIAL VEHICLE

Description

DESCRIPTION of the patent for Industrial Invention entitled: “ELECTRIC AXLE FOR INDUSTRIAL OR COMMERCIAL VEHICLE” * * * Field of application of the invention The present invention relates to the field of systems of electric propulsion, particularly in the field of industrial and commercial vehicles. The electric axle of the present invention belongs to that category of axles called off-axis, as the axis of rotation of the at least one electric motor is parallel but not coaxial with the semi-axes that define the axle. State of the art In the field of commercial and industrial vehicles it is in a massive electrification is underway which sees the replacement of internal combustion engines or their combination with electric motors. Industrial and commercial vehicles are made for maximizing cargo space, therefore, one of the fundamental aspects concern the construction of axles compact as well as robust. Furthermore, it must be considered that such vehicles require of even significant driving torques / powers and to achieve such pairs / powers it is necessary to provide transmissions that ensure a significant transmission ratio or the use of two electric machines. It is therefore not easy to balance compactness and a high transmission ratio or the arrangement of two machines electrical and transmission with respect to the constraints vehicular. Summary of the invention The purpose of the present invention is to present a electric axle for industrial or commercial vehicles particularly compact but able to guarantee a high gear ratio. The basic idea of ​​the present invention is that of connect the pinion of an electric motor with the port of input of an axle differential by at least one intermediate shaft defined by - a first group defined by: + an epicyclic gear train generally called in English language as “planetary gearset”, + a first drive wheel configured for mesh with said pinion and operationally connected with an epicyclic gear input port by means of a first, hollow tree, - a second group comprising + a second shaft coaxial with said first shaft, operationally connectable with an output port epicyclic gearing, + a second drive wheel, keyed onto a third shaft, coaxial with the epicyclic gear train, arranged to mesh with the differential crown of the axle, in which the third shaft is operationally connectable to the second tree. In a common plane of arrangement lie the said pinion and said first drive wheel, and in which the engine electric is arranged in a position opposite to the gear train epicyclic with respect to the common plane of rotation. Preferably, the differential is arranged in accordance with to the electric motor with respect to the common plane of arrangement. Advantageously, the first gear wheel has a diameter greater than the pinion allowing to obtain a first reduction of the transmission ratio, moreover, being the electric motor and differential arranged in a common half-space identified by the aforementioned common plane of position, the diameter of the first wheel, as well as the diameter of the fixed crown of the epicyclic gear depends on the radial dimensions of the electric motor and the differential. Dependent claims describe preferred variants of the invention, forming an integral part of this description. Brief description of the figures Further objects and advantages of the present invention will be clear from the detailed description that follows an example of its implementation (and its variants) and the attached drawings given purely for information purposes explanatory and non-limiting, in which: Figure 1 shows an example of a propulsion scheme based on the transmission relating to a first engine electric and an optional transmission related to a optional second electric motor; Figures 5a and 5b show variants related to the transmission of the first electric motor in figure 1; Figures 2 – 4 show further variants of the scheme propulsion, based on the transmission of figures 1, 5a and 5b, where further examples of transmissions are shown relating to the second optional electric motor. The same numbers and reference letters in the figures identify the same elements or components or functions. It should also be noted that the terms "first", "second", "third", "superior", "inferior" and the like can be used here to distinguish various elements. These terms do not imply a spatial, sequential or hierarchical order for the modified elements unless specifically indicated or deducible from the text. The elements and characteristics illustrated in the different preferred embodiments, including drawings, can be combined with each other without going out from the scope of protection of this application as described below. Detailed description of examples of implementation Figures 1 – 4 show four different variants of the electric axle which is the subject of the present invention. In all variants a first machine is shown electric E-motor 1 and a second electric car E- motor 2, however only the first electric car is essential, while the second one with a relative transmission connecting to the axle is entirely optional. In the following, the term "engine" refers to a machine electric capable of generating driving torque or torque resistant when functioning as a motor or engine respectively generator. The solution shown here refers to a configuration called off-axes as the tree of the electric motor is parallel but not coaxial with the axle AX schematically identified on the X-axis. The vehicle axle comprises at least one right wheel and one left wheel W and a differential DF. The differential, as is known in itself, it includes a crown K, defining the door of entrance, and two exit doors coinciding with the HAX half-shafts connecting the W wheels. The crown is integral in rotation with the differential satellite carrier, via the differential box itself. In the following the term “wheel” is used, meaning "cogwheel", having the task of transfer the rotational motion from one shaft to another drive shaft. The first electric motor E-motor 1 includes a relative first pinion P1, keyed onto a relative crankshaft, which transmits the motion to the input port K of the differential via an intermediate shaft X1. The intermediate shaft X1 is defined by + a first G1 group comprising: - an EAX epicyclic gear train preferably with axes parallels, - a first R1 drive wheel configured for engage with said first pinion P1 and operationally connected, and preferably coaxial, with the solar of the epicyclic gear train through a first shaft S1, cable, - a second shaft S2 coaxial and internal to the said first tree S1, operationally connected with the satellite holder C defining the output port of the epicyclic gearing, - a second transmission wheel R2, keyed onto a third shaft S3, coaxial with the gear train epicyclic, arranged to mesh with the crown K of the axle differential, in which the third shaft it is operationally connectable to the second shaft. In a common LP plane lie the first pinion P1 and the first transmission wheel R1. The first electric motor E-motor 1 is arranged in one position opposite to the EAX epicyclic gearing with respect to the common LP plane of arrangement. According to the present invention, the axis identified by the electric machine, the axis identified by at least one intermediate shaft and axle Ax are all mutually parallels. The solution which is the object of the present invention, maintaining the epicyclic gearing offset from the body of the electric machine and the differential allows to obtain a radial packing with respect to the optimal X-axis of all architecture and components. The epicyclic gear train can be simple with a fixed crown with a fixed transmission point, or compound, that is, with several epicyclic gears in series, or “stepped” or “compound” as they usually are called the solutions in which a satellite has two wheels constrained to each other in rotation, and the gear train has a entrance solar and a fixed crown with a fixed point of the transmission. Preferably, the gear train input port epicyclic coincides with the relative solar, while the The output port of the epicyclic gear coincides with the relative satellite carrier C. The third shaft S3 is preferably connectable with the second shaft S2 by means of a clutch or clutch CL1, preferably of absolute synchronized type or of type quick coupling, front or radial. More preferably, said connection is made by means of a CL1 selection device capable of to graft alternately - the M1 hub is integral in rotation with the carrier satellites C via the second shaft S2, or - the hub M2 is integral in rotation with the wheel R2 through the first tree S1. The CL1 device, comprises a sliding sleeve, constantly gripping the S3 shaft, which defines a three-position coupling system and thus creates a two-speed gearbox system with central position of disconnection or neutral. Advantageously, it is possible to realize at least three configurations in which the motion is generated by the first mover electric reaches the R2 wheel, through the connection direct connection of the S1 and S3 or S2-S3 shafts. Alternatively, the electric motor is disconnected from the differential by disconnecting the CL1 sleeve from both hub M1 than from hub M2. It is quite evident that when a graft is implemented CL1 able to alternately engage one of the two hubs M1 and M2, then, wheel R1 is arranged substantially in an intermediate position between the solar EAX gear train and M1 hub. Preferably, it is implemented a pair of B1 support pads, fitted externally to the S1 shaft and arranged on opposite sides of the R1 wheel, ensuring optimal shaft support S1. The shaft S2 is then supported by a bearing B2 which insists on the satellite carrier and a B3 bearing intermediate between the hollow shaft S1 and the shaft S2. The shaft S3 It is supported by an additional pair of B4 bearings, different and separate from the bearings supporting the S1 shafts and S2 and preferably arranged on opposite sides of the R2 wheel. The CL1 sleeve preferably comprises means of electric or hydraulic or pneumatic actuation for realize the configurations described above. The intermediate shaft X1, therefore, can be seen ideally as the sum of the trees (S1 OR S2) AND S3. Where, S1 and S2 are part of the first group G1 and S3 is part of the second group G2. In the following, the symbol DL1 indicates the first transmission relating to the first electric motor E-motor 1. As can be seen from any of the attached figures, the first wheel R1 with pinion P1 lie in a plane of LP position which evidently identifies two semi-spaces. In the sheet such a plane LP identifies two half-planes. In the half-plane The epicyclic gear train is located on the left side of the sheet EAX, while in the right half-plane of the sheet is placed the first engine E-motor 1 and more preferably also the differential DF, which therefore does not result in medial position of the AX axis. This solution, therefore, allows for the creation of a compact electric axle both in axial direction, i.e. along the X-axis defined by the AX axis, which in the direction transverse / radial to the axial direction. According to further preferred variants of the invention, DF differential is associated with an additional electric motor via a related DL2 transmission. Figure 4 shows a solution where the second engine electric E-motor 2 is operationally associated with the differential through a transmission identical to the transmission of the first electric motor. Preferably, on the same LP plane lie the first pinion P1, of the first electric motor, and the second pinion P2, of the second electric motor. Figures 1 – 3, unlike figure 4, show solutions in which the second electric motor is operationally associated with the differential by means of a different transmission DL2 compared to transmission DL1 relative first electric motor. Figure 2 shows the simplest solution among those of figures 1 – 3, as the first transmission DL1 relating to the first E-motor1 engine is able to define two different reduction gears using the CL1 clutch, and the second DL2 transmission relating to the second engine electric E-motor2 single reduction gear. The second pinion P2 of the second electric motor E-motor 2 engages a third input wheel R3 of the second DL2 transmission, integral with a fourth S4 shaft coaxial with a fifth shaft S5 that supports the wheel R4, of the second transmission output, which engages on the crown K of the differential DF. It is evident that the The terms “input” and “output” are to be considered as labels and not as functional characteristics, as torque can pass from the electric motor to the wheels in case of propulsion or from the wheels to the electric motor in the event of regenerative braking. In the context of this description if it is stated that “a tree supports a wheel” or “a tree is equipped with a wheel” or “a wheel / sprocket is keyed to a "tree" means, unless further specified, that the two components are fixed to each other. The S4 and S5 shafts are coaxial and connectable. by means of an additional clutch or CL2 coupling. For example, the CL2 coupling includes a sliding sleeve similar to the CL1 sliding sleeve described above, determining in a condition the interconnection of the trees S4 and S5 and in another condition the separation mechanical, neutral, of the same trees allowing the disconnection of the second electric machine with respect to the differential DF and therefore with respect to the wheels W. In relation to the most favorable transmission ratio, the first electric machine can be kept operational or the second electric machine or both, as both CL1 and CL2 grafts are capable of producing connecting and disconnecting the respective machines electric with respect to the DF differential and therefore with respect to the W wheels. The diameter of the R3 wheel can be the same or different to the diameter of the R1 wheel. As well as the diameter of the R4 wheel can be equal or different to the diameter of the R2 wheel. Preferably, the wheel diameters R3 and R4 are different from the diameter of the wheels R1 and R2 respectively, in order to obtain different transmission ratios between the first and second electric motor with respect to the K crown of the differential. Advantageously, the gear shift conditions of the first transmission are different from the change conditions gear (if possible) of the second transmission: this allows the so-called "torque filling" to be achieved when changing gear in first transmission or of the second transmission, ensuring propulsion even during gear changes. The solution in figure 1 differs from the solution of figure 2 for the presence of a second tree intermediate X3 which defines a further “drop” or “jump”. The second intermediate shaft X3 includes a fifth wheel R5 arranged to mesh with the second pinion P2 of the second electric motor E-motor 2 and a sixth wheel R6 arranged to engage the third input wheel R3 of the second intermediate shaft X2. This solution allows therefore the increase in the overall transmission ratio between the pinion P2 and wheel R3 and consequently the increase in the driving torque at the expense of final rotation speed to the crown K. Again the first intermediate shaft X2 of the second transmission, includes a CL2 clutch or clutch. The solution in figure 3, which shows two gears for each of the two transmissions DL1, DL2, differs from those of the previous figures, due to the fact that the second DL2 transmission relating to the second electric motor E- motor 2 includes two gears. On the shaft of the second electric motor are fitted a first P2 and a second pinion P3. The first pinion P2 meshes with the third wheel R3 similarly to the solution in figure 2. However, the transmission further includes a fifth gear wheel R5 keyed onto a hollow S6 shaft and coaxial with the S4 shaft. The fifth gear wheel R5 meshes with the second pinion P3 of the second electric motor E-motor 2. An additional M4 hub is fitted to the S6 hollow shaft and in this case the sliding sleeve of the CL2 coupling is arranged to alternately engage the M3 hub integral in rotation with the wheel R3, on the shaft S4, and the M4 hub integral in rotation with the S6 hollow shaft and then to the R5 wheel. In figure 3 the M4 hub is shown with teeth internal, while the M3 hub maintains the configuration with external teeth as in the case of figure 2. Therefore the sliding sleeve of the CL2 coupling, in this example, must include an internal dentition complementary to the M3 hub and an external one complementary to the M4 hub. Preferably, the CL2 coupling is also suitable for completely disconnect the second electric motor from the DF differential, assuming a neutral configuration of the second broadcast. In general, when a second electric motor is present with a relative transmission, it is preferred that also the CL1 graft is able to assume the configuration of neutral so as to disconnect the first electric motor from the DF differential. It is worth highlighting that both broadcasts of the the first and second electric motors are interfaced with the same K crown of the differential. In all variants where the second engine is foreseen electric E-motor 2, this last one is arranged so consistent with the differential and the first electric motor compared to the PL layout, improving the overall dimensions of the electric axle. All the solutions in figures 1 - 4 also include a DFL differential lock device. This is preferably made using a sliding sleeve able to make one of the rotating parts solidary with each other half shafts with satellite carrier / differential box, that is, with the crown K of the same. It is preferably placed near the floor LP position. This configuration guarantees optimal electric axle compaction, which can be pushed up to the limits of the mutual radial distance between the wheel R1, and possibly R5, and the locking system DFL differential itself. All solutions related to the second transmission provide for the implementation of at least one intermediate tree X2. While according to figure 1, the second transmission implements two intermediate trees X2 and X3. It is worth highlighting that the so-called “drop” or “jump” made from the set of trees X2 and X3 shown in figure 1 relating to the second transmission, can be implemented in any of the solutions of the figures 1 – 4 relating to the first DL1 transmission, as shown, for example, in Figures 5a and 5b. Advantageously, the introduction of the drops of figures 5a and 5b allows you to limit the size of the R1 wheels in the first transmission and R5 in the second transmission, to equal output ratio between the machine pinions electric and the wheels themselves R1 and R5, in order to be able to further compact the transverse extension, to the axis x, of the electric axle thus being able to bring the axes closer X1 and X2 to the DF differential and its system DFL lock. In figures 5a and 5b the drop between the P1 pinion of the shaft motor and the input wheel R1 of the intermediate shaft X1 is achieved by the X3_bis tree which includes a seventh wheel R7 arranged to mesh with pinion P1 and an eighth R8 wheel arranged to mesh with the first R1 wheel. Comparing figures 5a and 5b it can be noted that they differ in the relative position of the R7 wheels and R8. In particular, in relation to the diameter of the wheel R1 to maximize packing. In case of simultaneous operation, the two machines electric ones can work by selecting the maximum ratio available through the gears on which insist, allowing start-up functions from a standstill to high torque to meet the needs of the vehicle fully loaded on the ramp. Another function that can be implemented is that of possible propulsion by only one of the two electric cars for example in conditions high speed, low torque highway required for the vehicle's progress. The combination of these modes of operation therefore allows the maximization of the energy efficiency of the propulsion system being able to actually vary its configuration electric machines engaged and their ratios transmission. This disconnection condition also allows the vehicular propulsion with only one of the two machines electrical, for example in case of failure of the other, ensuring operational redundancy. Advantageously, the This invention also finds application in means of rescue. Disconnecting both transmissions from the electric machines finally allow for easy towing of the vehicle in case of breakdown. Implementation variations to the example are possible. limiting described, without however going beyond the scope of protection of the present invention, including all equivalent achievements for a technician in the field, content of the claims. From the description above the technician of the field is in able to realize the object of the invention without introduce further construction details. Legend: W wheels HAX half shafts AX axle X-axis development axis DF differential DFL differential lock differential crown K AND- first electric car motor1 AND- second electric car motor2 first DL1 broadcast second DL2 broadcast first pinion of E-motor1 P1 second pinion of E-motor2 P2 third sprocket of E-motor2 P3 first intermediate shaft X1 second intermediate shaft X2 additional X3 reduction and layshaft X3_bis reduction and layshaft first group G1 second group G2 EAX epicyclic gear train first drive wheel R1 second drive wheel R2 third wheel drive R3 fourth drive wheel R4 fifth wheel drive R5 sixth drive wheel R6 seventh drive wheel R7 R8 eighth drive wheel first tree S1 second tree S2 third tree S3 fourth tree S4 fifth tree S5 sixth tree S6 LP bed plane Planetary carrier of the epicyclic gear train C first CL1 graft second CL2 graft first M1 hub second hub M2 third hub M3 fourth M4 hub

Claims

CLAIMS 1. Electric axle for industrial or commercial vehicle comprising - a differential (DF) equipped with an input port (K) and shafts for rotating an equal number of vehicle wheels (W), - a first electric motor (E-motor 1) having a drive shaft on which a first pinion (P1) is keyed to transmit the motion to the input port (K) of the differential via at least one transmission (DL1) comprising a first intermediate shaft (X1) defined by + a first group (G1) comprising: - an epicyclic gear train (EAX), - a first transmission wheel (R1) configured to mesh with said first pinion (P1) and operatively connected to an input port of the epicyclic gear train by means of a hollow first shaft (S1), - a second shaft (S2) coaxial with said first shaft (S1), operatively connected to an output port of the epicyclic gear train, + a second group (G2) comprising: - a second wheel (R2) transmission,keyed to a third shaft (S3), coaxial with the epicyclic gear train, arranged to mesh with said input port (K), wherein the third shaft is operably connectable with the second shaft (S2), wherein the first transmission wheel (R1) defines a bearing plane (LP) and wherein the first electric motor (E-motor 1) is arranged in a position opposite to the epicyclic gear train (EAX) with respect to the bearing plane (LP)., 2. Axle according to claim 1, wherein the differential is arranged in accordance with the first electric motor with respect to the lying plane.

3. Axle according to claim 1 or 2, wherein said third shaft (S3) is operably connectable to said second shaft (S2) by means of a first coupling (CL1).

4. Axle according to claim 3, wherein said coupling (CL1) is adapted to operatively and alternatively connect the second wheel (R2) with said output port of the epicyclic gear train and with said first wheel (R1) defining a two-speed gearbox.

5. Axle according to claim 4, wherein said coupling is adapted to define a condition of disconnection of the second wheel (R2) from said first electric motor (E-motor 1).

6. Axle according to claim 4 or 5, wherein the clutch (CL1) is positioned next to the first electric motor in a radial direction to the drive shaft of the first electric motor.

7. Axle according to claim 6, wherein said coupling (CL1) is arranged between the first electric motor and the differential (DF).

8. Axle according to any of claims 3 - 7, wherein said second shaft (S2) supports at a first end a planet carrier (C) of the epicyclic gear train and at a second end, opposite to the first, a first hub (M1) operably connectable to said first coupling (CL1).

9. Axle according to any of claims 3 or 8, wherein said first hollow shaft (S1) supports at a first end a sun gear of the epicyclic gear train and at a second end a second hub (M2) and wherein said first transmission wheel (R1) is arranged in an intermediate and coaxial position between the sun gear of the epicyclic gear train and the second hub (M2) of the first shaft (S1).

10. Axle according to claim 9, wherein said first coupling (CL1) comprises a sliding sleeve adapted to engage alternately with said second hub (M2) and said first hub (M1) or adapted to remain disconnected from both the first and second hubs (M1 and M2).

11. Axle according to any of the preceding claims, wherein said bearing plane is common to said first wheel (R1) and said pinion (P1) of the electric motor.

12. Axle according to any of the preceding claims 1 - 10, wherein said first transmission (DL1) further comprises a return and reduction shaft (X3_bis), arranged between the electric motor and the first intermediate shaft (X1).

13. An axle according to any of the preceding claims 1 - 12, further comprising a second electric motor (E-motor 2) comprising a second pinion (P2) arranged to drive in rotation the input port (K) of the differential by means of a respective second transmission (DL2).

14. Axle according to claim 13, wherein said second transmission comprises a second intermediate shaft (X2) identical to the first intermediate shaft (X1).

15. [fig. 2] Axle according to claim 13, wherein said second transmission comprises a second intermediate shaft (X2) comprising - a fourth shaft (S4) on which is keyed a third wheel (R3) arranged to mesh with said second pinion (P2) and a third hub (M3) and - a fifth shaft (S5) coaxial with the fourth shaft equipped with a fourth wheel (R4) arranged to mesh with the input port (K) of the differential and a second clutch (CL2) arranged to selectively connect in rotation the fifth shaft (S5) with the third hub (M3).

16. [fig. 1] Axle according to claim 13, wherein said second transmission comprises a second intermediate shaft (X2) and a further reduction and return shaft (X3), wherein the second intermediate shaft (X2) comprises - a fourth shaft (S4) on which is keyed a third wheel (R3) arranged to mesh with a sixth wheel (R6) of the further reduction and return shaft (X3) and a third hub (M3) and - a fifth shaft (S5) coaxial with the fourth shaft (S4) equipped with a fourth wheel (R4) arranged to mesh with said input port (K) of the differential and a second clutch (CL2) arranged to selectively connect in rotation the fifth shaft (S5) with the third hub (M3) of the fourth shaft (S4), and wherein the further reduction and return shaft (X3) comprises a sixth shaft (S6) arranged to stably support said sixth wheel (R6) and to support a fifth wheel (R5) arranged to mesh with said second pinion (P2).

17. [fig. 3] Axle according to claim 13, wherein said second electric motor comprises said second pinion (P2) and a third pinion (P3) keyed to the relative drive shaft and wherein said second intermediate shaft (X2) comprises - a fourth shaft (S4) supporting a third wheel (R3) arranged to mesh with said second pinion (P2) and a third hub (M3) operatively connected to the fourth shaft (S4), - a sixth shaft (S6), hollow and coaxial with the fourth shaft (S4), supporting a fifth wheel (R5) arranged to mesh with the third pinion (P3) and operatively connected to a fourth hub (M4), - a fifth shaft (S5) coaxial with said fourth and sixth shafts, supporting said fourth wheel (R4) and said second clutch (CL2), configured to alternately engage the third or fourth hub or to create a neutral configuration.

18. Axle according to any of the preceding claims, wherein the differential is equipped with a locking device (DFL), preferably housed in correspondence with said lying plane.