Combined offset gearbox arrangement for hybrid-electric powerplant

1 . A propulsion system for an aircraft, the propulsion system comprising:

an engine comprising a first input shaft; and

a drivetrain coupled to the first input shaft, the drivetrain comprising an output shaft, a gear assembly, an electric motor, and a second input shaft,

the gear assembly comprising a main gear mounted to the output shaft, and a bevel ring gear integrated on a face of the main gear, wherein the main gear, the bevel ring gear, and the output shaft are rotatable about a first rotational axis,

the electric motor comprising a rotor rotatable about a second rotational axis, wherein the second rotational axis is perpendicular to the first rotational axis, and

the second input shaft coupling the rotor to the bevel ring gear, the second input shaft being rotatable about the second rotational axis.

2 . The propulsion system of claim 1 , further comprising a propulsor mounted on the output shaft and rotatable about the first rotational axis.

3 . The propulsion system of claim 1 , wherein the second input shaft extends from a proximal end coupled to the rotor to a distal end having a bevel input gear, and wherein the bevel input gear is perpendicularly engaged with the bevel ring gear.

4 . The propulsion system of claim 1 , further comprising a propeller control unit (PCU) coupled to the output shaft.

5 . The propulsion system of claim 4 , wherein the gear assembly comprises a reduction gear assembly including the main gear and at least one offset gear, the at least one offset gear being coupled to an accessory load.

6 . The propulsion system of claim 5 , wherein the main gear is engaged with the at least one offset gear.

7 . The propulsion system of claim 5 , wherein the accessory load comprises an oil pump connected in fluid communication with the PCU.

8 . The propulsion system of claim 1 , wherein the gear assembly comprises a reduction gear assembly including the main gear and at least one offset gear, the at least one offset gear being coupled to the first input shaft, and the first input shaft being rotatable about a third rotational axis radially offset from the first rotational axis.

9 . The propulsion system of claim 1 , wherein the drivetrain further comprises a gearbox housing, and the electric motor further comprises a static structure engaged with the rotor and coupled to the gearbox housing.

10 . A propulsion system for an aircraft, the propulsion system comprising:

an engine comprising a first input shaft; and

a drivetrain coupled to the first input shaft, the drivetrain comprising an output shaft, a reduction gear assembly, and an electric motor,

the reduction gear assembly comprising at least a main gear, a first offset gear, and a bevel ring gear, the main gear being mounted to the output shaft, the bevel ring gear being integrated on a face of the main gear, the first offset gear being coupled to the first input shaft, and the main gear, the bevel ring gear, and the output shaft being rotatable about a first rotational axis, and

the electric motor comprising a rotor rotatable about a second rotational axis, the second rotational axis being perpendicular to the first rotational axis, and the rotor being coupled to the bevel ring gear.

11 . The propulsion system of claim 10 , further comprising a propulsor mounted on the output shaft and rotatable about the first rotational axis.

12 . The propulsion system of claim 10 , wherein the drivetrain further comprises a second input shaft rotatable about the second rotational axis and coupling the rotor to the bevel ring gear.

13 . The propulsion system of claim 12 , wherein the second input shaft extends from a proximal end coupled to the rotor to a distal end having a bevel input gear, and wherein the bevel input gear is perpendicularly engaged with the bevel ring gear.

14 . The propulsion system of claim 10 , wherein the first input shaft is rotatable about a third rotational axis that is radially offset from the first rotational axis.

15 . The propulsion system of claim 10 , further comprising a propeller control unit (PCU) coupled to the output shaft.

16 . The propulsion system of claim 15 , wherein the reduction gear assembly further comprises a second offset gear coupled to an accessory load.

17 . The propulsion system of claim 16 , wherein the main gear is engaged with the second offset gear.

18 . The propulsion system of claim 16 , wherein the accessory load comprises an oil pump connected in fluid communication with the PCU.

19 . The propulsion system of claim 10 , wherein the drivetrain further comprises a gearbox housing, and the electric motor further comprises a static structure engaged with the rotor and coupled to the gearbox housing.

20 . A propulsion system for an aircraft, the propulsion system comprising:

an engine comprising an input shaft;

a drivetrain coupled to the input shaft, the drivetrain comprising an output shaft, a gear assembly, and an electric motor,

the gear assembly comprising a main gear mounted to the output shaft, and a bevel ring gear integrated on a face of the main gear, wherein the main gear, the bevel ring gear, and the output shaft are rotatable about a first rotational axis, and

the electric motor comprising a rotor rotatable about a second rotational axis, wherein the second rotational axis is perpendicular to the first rotational axis, and the rotor is coupled to the bevel ring gear; and

a propeller control unit (PCU) mounted on the output shaft.