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EP-4737767-A1 - ELECTRIC DRIVE AXLE FOR INDUSTRIAL OR COMMERCIAL VEHICLE

EP4737767A1EP 4737767 A1EP4737767 A1EP 4737767A1EP-4737767-A1

Abstract

Electric axle (EA) for industrial or commercial vehicles comprising a differential (DIF) equipped with an input port and half-shafts (HS) to rotate corresponding vehicle wheels (W), a first electric machine (EM1, EM2) having a drive shaft, a transmission comprising: an epicyclic gear train (PG) coaxial with said half-shafts (HS) and comprising a single output port (SC) coinciding with said input port of the differential, a first input port (M1, S) and a second input port (M3, SC) selectively connectable to a first hollow shaft (S2) coaxial with said half-shafts (HS), wherein said first and second input ports are selectable by means of a first selection device (CL1) and wherein said first shaft (S2) is operably connectable to said first electric machine by means of a second selection device (CL2).

Inventors

  • PESOLA, FABIO
  • ESPOSITO, PIETRO
  • CANTONE, Francesco
  • TESSITORE, MARCO

Assignees

  • FPT Industrial S.p.A.

Dates

Publication Date
20260506
Application Date
20251020

Claims (19)

  1. Electric power axle (EA) for an industrial or commercial vehicle comprising: - a differential (DIF) equipped with an input port and half-shafts (HS) to rotate corresponding vehicle wheels (W), - a first electric machine (EM1, EM2) having a drive shaft (SM, SM'), - a transmission comprising: + a planetary gear train (PG) coaxial with said half-shafts (HS) and comprising a single output port (SC) coinciding with said input port of the differential, a first input port (M1, S) and a second input port (M2, SC) selectively connectable to + a first shaft (S2) hollow and coaxial with said half-shafts (HS), wherein said first and second input ports are selectively connectable to said first shaft (S2) by means of a first selection device (CL1) and wherein said first shaft (S2) is connectable to said drive shaft (SM, SM') by means of a second selection device (CL2, CL3).
  2. Axle according to claim 1, wherein the first (CL1) and/or second selection device (CL2) is - a non-absolute dog-clutch quick-release coupling with front or radial teeth for selectively engaging two wheels or two hubs defining two gears, - an absolute type, with friction cones, - or a combination of an absolute and non-absolute type clutch on opposite faces of the selection device.
  3. Axle according to claim 1 or 2, wherein said first shaft (S2) is connectable to said drive shaft (SM, SM') by means of a second selection device (CL2, CL3) belonging to a transmission (T) interposed between said first shaft and said drive shaft.
  4. Axle according to claim 3, wherein said transmission (T) comprises a second transmission shaft (S3, S4) operatively connected to said drive shaft (SM, SM') and wherein the first shaft is equipped with a pair of fixed secondary wheels (1, 2) that rotate with the first shaft (S2) and wherein the second shaft (S3, S4) comprises a pair of primary wheels (3, 4) that can be selectively connected for rotation with the second shaft (S3, S4) by means of said second selection device (CL2, CL3) and wherein the pair of primary wheels meshes with the pair of secondary wheels.
  5. Axle according to claim 4, wherein said second shaft (S3, S4) comprises an input wheel (IN) and the electric machine comprises a pinion (P, P') keyed to a related drive shaft (SM, SM'), and wherein the pinion is arranged to mesh with said input wheel.
  6. Axle according to claim 5, wherein said input wheel (IN) and said pinion (P, P') lie in a plane of arrangement (K) and wherein in a first half-space identified by the plane of arrangement (K) are housed said pairs of primary and secondary wheels and said first electric machine.
  7. Axle according to claim 5, wherein said input wheel (IN) and said pinion (P) lie in a plane of arrangement (K) and wherein in a first half-space identified by the plane of arrangement (K) are housed said pairs of primary and secondary wheels and in a second half-space, opposite to the first one, is housed said first electric machine.
  8. Axle according to any of claims 1 - 4, further comprising a second drive shaft (S3) coaxially connected to the drive shaft (SM, SM') of said first electric machine (EM1, EM2).
  9. Axle according to any of claims 1 - 3, further comprising a second shaft (S3) and wherein said drive shaft (SM, SM') supports a first and a second primary wheel (5, 6) and said second shaft comprises a first and a second secondary wheel (3, 4) wherein each of said first and second primary wheels meshes with a respective secondary wheel, and wherein the first and second secondary wheels are selectively connectable to the second shaft (S3) by means of said second selection device (CL2, CL3).
  10. Axle according to claim 98, wherein the first shaft (S2) comprises an input gear (1) fixed to the first shaft (S2) and the second shaft (S3) comprises an output gear (OUT) fixed to the second shaft (S3, S4), and wherein the input gear meshes with the output gear.
  11. Axle according to any of the preceding claims, wherein a sun gear (S) defines said first port of the epicyclic gear train and a planet carrier (SC) defines said second port of the epicyclic gear train.
  12. An axle according to any of the preceding claims 1-11, wherein said first selection device (CL1) comprises - a first hub (M1) fixed to said sun gear (S), - a second hub (M2) fixed to said planet carrier (SC), - a sliding sleeve (10) with at least one set of teeth (D) equipped with at least one set of teeth (D) capable of selectively engaging said first and second hubs.
  13. An axle according to claim 12, wherein said sliding sleeve is equipped with a first set of teeth and a second set of teeth, internal and external respectively.
  14. An axle according to any of claims 12 or 13, wherein the sliding sleeve is associated with the first shaft (S2) by means of a splined coupling.
  15. Axle according to claim 14, wherein the first shaft (S2) is equipped with a third hub (M3) and wherein the sliding sleeve is associated with the third hub (M3), wherein the sliding sleeve is equipped with internal splined teeth, the third hub is equipped with external splined teeth, and wherein the sliding sleeve is integral with a control collar (C1), interposed axially between the first shaft (S2) and the epicyclic gear train (PG).
  16. Axle according to claim 14, wherein said sliding sleeve is internal and coaxial with the first shaft (S2) and coupled to the first shaft (S2) by means of a splined coupling, and wherein a control collar (C1) of the sliding sleeve is in a proximal position to a first vehicular wheel, opposite to a second vehicular wheel, wherein the differential is in a proximal position with respect to the second vehicular wheel.
  17. An axle according to any of claims 1 to 16, further comprising a second electric machine (E2) operatively connected to said first shaft (S2) by means of a respective third shaft (S4) similar to said second shaft (S3) and preferably identical to said second shaft (S3).
  18. An axle according to any of the preceding claims, wherein said differential (DIF) is equipped with a locking device (DK) arranged to rotate the half-shafts (HS) together.
  19. An industrial or commercial vehicle comprising an electric axle according to any of claims 1 to 18.

Description

Field of the invention The present invention relates to the field of electric propulsion systems, particularly in the field of industrial and commercial vehicles equipped with single or dual electric motor electric axle drives. The electric axle drive of the present invention belongs to the category of axles known as off-axis, in that the rotation axis of one or more electric propulsion machines is parallel but not coaxial with the axle shafts that define the axle. State of the art Commercial and industrial vehicles are undergoing a massive electrification process, replacing internal combustion engines or integrating them with electric motors. Industrial and commercial vehicles are designed to maximize cargo space, so one of the key aspects is the design of compact and robust drive axles. Furthermore, it must be considered that these vehicles require significant torque/power, and to achieve this torque/power, it is necessary to provide transmissions that guarantee a significant gear ratio or the use of two electric motors. It is therefore not easy to balance compactness and a high gear ratio, or the arrangement of two electric motors and the transmission, with respect to vehicle constraints. More specifically, in the field of industrial and commercial vehicles, a high efficiency of the axle is required at motorway speeds, i.e. when there is a low reduction ratio between the shaft of the electric motors and the wheel hubs, limiting as much as possible the number of meshing wheels in this specific driving condition and therefore the losses due to the transmission of torque between the gear wheels involved in the meshing. Summary of the invention The purpose of this invention is to present a particularly compact, single- or dual-motor electric axle drive for industrial or commercial vehicles, capable of ensuring a high reduction ratio in one operating condition and high efficiency in another operating condition, when the reduction ratio is low. The basic idea of this invention is to implement a transmission comprising a planetary gearset as a final reduction stage connected to a differential, in which the planetary gearset is coaxial with the axle. The planetary gearset has two distinct inputs and an output operationally connected to the input of the axle differential. A hollow shaft, coaxial with the planetary gearset, can be selectively connected to one of the two inputs of the planetary gearset by means of a first selection device. A first additional shaft supports a pair of gear wheels that can be selectively connected to the same additional drive shaft via a second additional selection device to transmit motion to the hollow shaft. Advantageously, at least four gears can be achieved. The axle drive can be equipped with an additional electric motor and a respective second additional drive shaft with a respective third additional selection device to transmit motion to the hollow shaft. Advantageously, the axle drive can achieve a minimum of four gears and a maximum of eight gears if configured with two electric motors. The dependent claims describe preferred variants of the invention and form an integral part of this specification. Brief description of the figures Further purposes and advantages of the present invention will become clear from the following detailed description of an embodiment thereof (and its variants) and the accompanying drawings, provided purely for explanatory and non-limiting purposes, in which: Figure 1 shows an example of a drive axle arrangement that is the subject of the present invention;Figure 2 shows a variant of the arrangement of Figure 1 in which the control of a selection device is moved to a more accessible position than in the arrangement of Figure 1;Figure 3 shows a solution, based on the arrangement of Figure 2, in which two electric machines are implemented;Figures 4 and 5 show further variants of the invention in which the drive shaft is equipped with a pair of pinions. The same reference numbers and letters in the figures identify the same elements or components or functions. It should also be noted that the terms "first," "second," "third," "upper," "lower," and the like may 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 implied by the text. The elements and features illustrated in the various preferred embodiments, including the drawings, may be combined without departing from the scope of protection of this application as described below. Detailed description of preferred embodiments Figure 1 shows a preferred layout of the EA electric axle drive of the present invention. The axle is defined by the two half-shafts HS arranged to rotate their respective wheels W. The half-shafts are connected to the differential DIF, for rotational drive. A planetary gear PG is configured coaxially with one of the half-shafts HS. The planetary carrier SC i