Electric axle assembly and operating method
Methods and systems for an electric axle assembly are provided herein. The electric axle assembly includes, in one example, an electric machine with a rotor shaft having an output gear thereon. The electric axle assembly further includes a planetary gearset with a carrier coupled to a pair of axle shafts, a first ring gear with external teeth that are rotationally coupled to the output gear; and a sun gear meshing with a plurality of planet gears that rotate on the carrier, where, in the axle assembly, internal teeth of the ring gear are rotationally coupled to the plurality of planet gears, and where, in the axle assembly, the sun gear or the carrier are grounded by a housing of the electric axle assembly.
1 . A one-speed electric axle, comprising:
an electric machine with a rotor shaft with an output gear that is coupled thereto; and
a planetary gearset rotationally coupled to a differential and including:
a ring gear with external teeth that mesh with the output gear; and
a sun gear meshing with a first plurality of planet gears that rotate on a carrier;
wherein internal teeth of the ring gear are rotationally coupled to the first plurality of planet gears;
wherein the sun gear or the carrier is permanently grounded by a housing of the one-speed electric axle; and
wherein the planetary gearset does not include any clutches or brakes.
2 . The one-speed electric axle of claim 1 , wherein the differential includes spider gears that mesh with side gears.
3 . The one-speed electric axle of claim 1 , wherein teeth of the output gear mesh with external teeth of the first ring gear.
4 . The one-speed electric axle of claim 1 , wherein a rotational axis of the electric machine is parallel to rotational axes of a pair of axle shafts that are coupled to the differential.
5 . The one-speed electric axle of claim 1 , wherein the one-speed electric axle is included in an all-electric vehicle.
6 . The one-speed electric axle of claim 1 , wherein the one-speed electric axle is included in a hybrid electric vehicle.
7 . The one-speed electric axle of claim 1 , further comprising an inverter electrically coupled to the electric machine.
8 . The one-speed electric axle of claim 1 , wherein the housing at least partially encloses the electric machine and the planetary gearset.
9 . The one-speed electric axle of claim 1 , further comprising a pair of electrically actuated torque vectoring devices positioned between the pair of axle shafts and the carrier.
10 . The one-speed electric axle of claim 1 , wherein the sun gear is grounded by the housing.
11 . A method for operation of a one-speed electric axle, comprising:
transferring rotational energy from an electric machine to a ring gear of a planetary gearset; and
wherein the planetary gearset is rotationally coupled to a differential and includes:
the ring gear with external teeth that are rotationally coupled to a gear that is rotationally coupled to a rotor shaft of the electric machine; and
a sun gear meshing with a plurality of planet gears that rotate on a carrier;
wherein internal teeth of the ring gear are rotationally coupled to the plurality of planet gears;
wherein the sun gear is permanently grounded by a housing of the one-speed electric axle; and
wherein the planetary gearset does not include any clutches or brakes.
12 . The method of claim 11 , wherein the electric machine is an electric motor-generator.
13 . A one-speed electric axle, comprising:
an electric motor-generator with a rotor shaft with a gear that is coupled thereto; and
a planetary gearset coupled to a differential and the planetary gear set and including:
a ring gear that includes a first set of internal teeth and a second set of internal teeth;
a sun gear meshing with a plurality of planet gears that rotate on a carrier;
wherein the planetary gearset does not include any clutches or brake; and
wherein internal teeth of the ring gear are rotationally coupled to the plurality of planet gears.
14 . The one-speed electric axle of claim 13 , further comprising a housing at least partially enclosing the differential and including a section that extends along a side of the electric motor-generator.
15 . The one-speed electric axle of claim 14 , wherein the housing section is position vertically below the electric motor-generator.