Methods and systems for a multi-speed electric axle assembly

1. A multi-speed electric axle assembly with three discrete gear ratios, comprising:

one or more electric motor generators;

a hollow shaft coupled coaxially to the one or more electric motor generators;

one or more Ravigneaux gear assemblies, the one or more Ravigneaux gear assemblies providing the three discrete gear ratios,

a first Ravigneaux gear assembly comprising a sun gear connected concentrically with the hollow shaft and a ring gear coupled to a first gear set and a second gear set;

a first axle shaft extending through the hollow shaft and a second sun gear concentric with the first axle shaft driven by the first gear set;

a second axle shaft coupled to the second gear set;

a plurality of clutches coupled to different gears; and

a controller designed to, while the one or more electric motor generators are generating mechanical power, selectively engage a first clutch in the plurality of clutches to engage selected gears in the one or more Ravigneaux gear assemblies to permit the multi-speed electric axle assembly to operate in one of the three discrete gear ratios and selectively engage a second clutch to a gear reduction;

wherein the first clutch is positioned between the first axle shaft and the second axle shaft and coaxial to the one or more Ravigneaux gear assemblies.

2. The multi-speed electric axle assembly of claim 1 , wherein the first clutch is directly coupled to a sun gear of a differential.

3. The multi-speed electric axle assembly of claim 1 , wherein power is transmitted from the one or more electric motor generators to only one side of a first Ravigneaux gear assembly of the one or more Ravigneaux gear assemblies, the power is transmitted to the first axle shaft through a second sun gear coaxial with the first axle shaft, the second sun gear engaged with the first gear set, the power transmitted to the second axle shaft through a second ring gear engaged with the second gear set.

4. A multi-speed electric axle assembly for a vehicle, comprising:

a first electric motor generator that is positioned coaxial to a first axle shaft and a second axle shaft, wherein the axle shafts are coupled to two wheels;

a hollow shaft operably coupled coaxially to the first electric motor generator for rotation;

a first gear assembly mechanically coupled to the hollow shaft, the first gear assembly comprising:

a first sun gear operably coupled concentrically to the hollow shaft;

a ring gear coupled to a first gear set and a second gear set;

the second gear set is connected to the first gear set and a second sun gear;

a first axle shaft extending through the hollow shaft and the second sun gear concentric with the first axle shaft driven by the first gear set;

a second axle shaft coupled to the second gear set;

a plurality of clutches coupled to different gears in a gear reduction;

and a controller designed to, while the first electric motor generator is generating mechanical power, selectively engage a first clutch in the plurality of clutches to engage selected gears in the first gear assembly to permit the multi-speed electric axle assembly to operate in one of three discrete gear ratios and engage a second clutch to the gear reduction;

wherein the first clutch is positioned between the axle shafts, coaxial to the first gear set, and directly coupled to the second sun gear.

5. The multi-speed electric axle assembly of claim 4 , wherein the first gear assembly is a Ravigneaux gear assembly; and

wherein the second gear set drives a second ring gear which drives the second axle shaft.

6. The multi-speed electric axle assembly of claim 4 , wherein the hollow shaft is rotatably supported by one or more bearings.