US-12617270-B2 - Gearbox for a front axle of an electric tractor

Abstract

Systems and methods are provided for electrifying a drivetrain of a vehicle. In one example, a gearbox for a vehicle a first gear coupled to a first input shaft configured to be driven by a first electric motor, a second gear configured to mesh with the first gear, and a third gear configured to mesh with the second gear and coupled to a third shaft configured to drive a first axle of the vehicle and connectable to a second axle of the vehicle. The gearbox further includes a fourth gear coupled to the first input shaft, a fifth gear coupled to a lay shaft coupled to the second gear, a sixth gear coupled to a second input shaft, and a seventh gear coupled to a power takeoff shaft configured to drive one or more power takeoff units, the second input shaft configured to be driven by a second electric motor.

Inventors

• Riccardo MORSELLI

Assignees

• DANA MOTION SYSTEMS ITALIA S.R.L.

Dates

Publication Date

20260505

Application Date

20240213

Claims (19)

1. 1 . A gearbox for a vehicle, comprising: a first gear coupled to a first input shaft, the first input shaft configured to be driven by a first electric motor of the vehicle; a second gear configured to mesh with the first gear; a third gear configured to mesh with the second gear and coupled to a third shaft, the third shaft configured to drive a first axle of the vehicle and connectable to a second axle of the vehicle, wherein the first gear, the second gear, and the third gear form a first gear set; a second gear set comprising a fourth gear coupled to the first input shaft and a fifth gear coupled to a lay shaft, the lay shaft coupled to the second gear; and a third gear set comprising a sixth gear coupled to a second input shaft and a seventh gear coupled to a power takeoff shaft, the power takeoff shaft configured to drive one or more power takeoff units, the second input shaft configured to be driven by a second electric motor.
2. 2 . The gearbox of claim 1 , further comprising a first disconnect device configured to selectively couple and decouple the first gear to the first input shaft.
3. 3 . The gearbox of claim 2 , wherein the first disconnect device is configured to selectively couple and decouple the fourth gear to the first input shaft.
4. 4 . The gearbox of claim 1 , wherein the first gear set is configured to transfer torque from the first input shaft to the third shaft with a first gear ratio, and wherein the second gear set is configured to transfer torque from the first input shaft to the third shaft with a second gear ratio, different than the first gear ratio.
5. 5 . The gearbox of claim 1 , wherein the power takeoff shaft comprises a first half shaft coupled to a first power takeoff unit of the one or more power takeoff units and a second half shaft coupled to a second power takeoff unit of the one or more power takeoff units, the first half shaft couplable to the second half shaft at the seventh gear.
6. 6 . The gearbox of claim 5 , further comprising one or more of: a second disconnect device configured to selectively couple and decouple the seventh gear to the first half shaft; a third disconnect device configured to selectively couple and decouple the seventh gear to the second half shaft; and a fourth disconnect device configured to selectively couple and decouple the sixth gear from the second input shaft.
7. 7 . A method for an electrified drivetrain of a vehicle, comprising: operating the electrified drivetrain in a first gear stage, including transmitting torque from a first input shaft coupled to an electric motor to an output shaft via a first gear set, the output shaft coupled to a first axle and/or a second axle; determining that a speed of the first input shaft has met a predetermined condition relative to a threshold, and in response, shifting from the first gear stage to a second gear stage and operating the electrified drivetrain in the second gear stage, including transmitting torque from the first input shaft to the output shaft via a second gear set; and determining that a request to operate a power takeoff unit has been received, and in response, transmitting torque from the first input shaft and/or from a secondary power source to the power takeoff unit via a power takeoff shaft and a third gear set, wherein the power takeoff shaft comprises a first half shaft and a second half shaft and wherein transmitting torque from the first input shaft and/or from the secondary power source to the power takeoff unit via the power takeoff shaft and the third gear set comprises transmitting torque from the secondary power source to the power takeoff unit via the second half shaft by decoupling the first half shaft from the third gear set via a first disconnect device and coupling a second input shaft to the second half shaft via the third gear set coupled to the second half shaft by a second disconnect device, the second input shaft driven by the secondary power source, the second half shaft coupled to the power takeoff unit.
8. 8 . The method of claim 7 , wherein shifting from the first gear stage to the second gear stage comprises decoupling the first input shaft from a first gear of the first gear set and coupling the first input shaft to the second gear set via a third disconnect device.
9. 9 . The method of claim 8 , further comprising operating the electrified drivetrain in a neutral stage where torque from the first input shaft is not transmitted to the output shaft and the third disconnect device decouples the first input shaft from the first gear set and from the second gear set.
10. 10 . The method of claim 7 , further comprising, while shifting from the first gear stage to the second gear stage, controlling a speed of the electric motor to synchronize a speed of the first input shaft to a speed of the second gear set.
11. 11 . The method of claim 7 , further comprising reducing a speed of the electric motor during operation of the electrified drivetrain in a neutral stage.
12. 12 . The method of claim 7 , wherein the power takeoff unit is a first power takeoff unit, and further comprising transmitting torque from the secondary power source to a second power takeoff unit via the first half shaft by decoupling the second half shaft from the third gear set via the second disconnect device and coupling the second input shaft to the first half shaft via the third gear set coupled to the first half shaft by the first disconnect device, the first half shaft coupled to the second power takeoff unit.
13. 13 . The method of claim 12 , further comprising transmitting torque from the secondary power source to both the first power takeoff unit and the second power takeoff unit via the first half shaft and the second half shaft each coupled to the third gear set via the first disconnect device and the second disconnect device.
14. 14 . An electrified drivetrain for a vehicle, comprising: a first input shaft configured to be driven by a first electric motor; a second input shaft configured to be driven by a second electric motor; a power takeoff shaft configured to be driven by the second electric motor; an output shaft coupled to a front differential and/or a rear differential; a gearbox including a first gear set and a second gear set each coupling the first input shaft to the output shaft and a third gear set coupling the second input shaft to the power takeoff shaft; and a first disconnect device configured to selectively decouple the output shaft from the first input shaft via the first gear set.
15. 15 . The electrified drivetrain of claim 14 , wherein the first gear set comprises a first gear, a second gear, and a third gear, the second gear meshing with the first gear and the third gear, and wherein the second gear set comprises a fourth gear that meshes with a fifth gear, the fifth gear coupled to a lay shaft, the lay shaft coupled to the second gear.
16. 16 . The electrified drivetrain of claim 15 , wherein the first gear and the second gear have a first gear ratio and the fourth gear and the fifth gear have a second gear ratio, different than the first gear ratio.
17. 17 . The electrified drivetrain of claim 15 , wherein the third gear set comprises a sixth gear coupled to the second input shaft and a seventh gear coupled to the power takeoff shaft.
18. 18 . The electrified drivetrain of claim 17 , wherein the power takeoff shaft comprises a first half shaft coupled to a first power takeoff unit and a second half shaft coupled to a second power takeoff unit, the first half shaft couplable to the second half shaft at the seventh gear.
19. 19 . The electrified drivetrain of claim 14 , wherein the first disconnect device is further configured to selectively couple and decouple the second gear set to the output shaft.

Description

RELATED APPLICATIONS The present application claims priority to U.S. Provisional Application No. 63/495,062, entitled “GEARBOX FOR A FRONT AXLE OF AN ELECTRIC TRACTOR,” and filed Apr. 7, 2023. The present application also claims priority to U.S. Provisional Application No. 63/489,678, entitled “GEARBOX FOR A FRONT AXLE OF AN ELECTRIC TRACTOR,” and filed Mar. 10, 2023. The entire contents of each of the above-identified applications is hereby incorporated by reference for all purpose. TECHNICAL FIELD The present description relates generally to a gearbox in a vehicle. More specifically, the present disclosure relates to a gearbox for an axle of an electric tractor. BACKGROUND AND SUMMARY Many agricultural tractors in use today are powered solely by an internal combustion engine. Replacing agricultural tractors solely powered by internal combustion engines with electric tractors has the potential to reduce the constant maintenance, noise and pollution associated with gas and diesel tractors. Additionally, electric tractors may require less upkeep than tractors employing internal combustion engines, which may reduce the repair time and cost required to keep the tractor running. Further, electric motors may produce higher torque at lower speed than internal combustion engines, which may be ideal for tractor operation. Agricultural tractors may be electrified through the front axle. However, the inventors herein have recognized potential issues with such a system. The utilization of an electric motor to drive the front axle of the tractor may make it difficult to install a four-wheel-drive shaft and may require larger front brakes than is standard. Further, a front installation of a power takeoff may require the electric motor to be positioned lower in the tractor, which may require a lower ground clearance for the tractor. Additionally, there may be a large speed difference (e.g., 4000+ rpm) between the electric motor and a pinion gear that transfers power from a drive shaft to a differential unless the motor is oversized. In one example, the issues described above may be addressed by a gearbox for a vehicle, where the gearbox includes a first gear coupled to a first input shaft, the first input shaft configured to be driven by a first electric motor of the vehicle, a second gear configured to mesh with the first gear; and a third gear configured to mesh with the second gear and coupled to a third shaft, the third shaft configured to drive a first axle of the vehicle and connectable to a second axle of the vehicle, wherein the first gear, the second gear, and the third gear form a first gear set. The gearbox further includes a second gear set comprising a fourth gear coupled to the first input shaft and a fifth gear coupled to a lay shaft, the lay shaft coupled to the second gear, and a third gear set comprising a sixth gear coupled to a second input shaft and a seventh gear coupled to a power takeoff shaft, the power takeoff shaft configured to drive one or more power takeoff units, the second input shaft configured to be driven by a second electric motor. It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a vehicle including an electric motor and a gearbox; FIG. 2 is a side view of a gearbox coupled to an electric motor, a power takeoff, a front differential, and a rear differential; FIG. 3 is a schematic diagram of the gearbox of FIG. 2 with the electric motor of FIG. 2 in a first position; FIG. 4 is a schematic diagram of the gearbox of FIG. 2 with the electric motor of FIG. 2 in a second position; FIG. 5 is a schematic diagram of a plurality of gears of the gearbox of FIG. 2 and a power takeoff shaft; FIG. 6A is a schematic diagram of a power path that occurs in the gearbox of FIG. 2 during a first gear stage; FIG. 6B is a schematic diagram of a power path that occurs in the gearbox of FIG. 2 during a second gear stage; FIG. 7A is a schematic diagram of a power path that occurs in the gearbox of FIG. 2 when the power takeoff of FIG. 2 is driven by a secondary power source; FIG. 7B is a schematic diagram of a power path that occurs in the gearbox of FIG. 2 when the power takeoff of FIG. 2 is driven by a secondary power source and the electric motor of FIG. 2; FIG. 7C is a schematic diagram of a power path that occurs in the gearbox of FIG. 2 when the power takeoff of FIG. 2 is driven by the electric motor of FIG. 2; FIG. 7D is a schematic diagram of a power path that occurs in the gearbox of FIG. 2 when