Multi-speed electric drive axle using multi-layshaft transmission
An electric drive axle with an electric motor having a motor shaft that is rotatable about an axis, a differential, and a transmission. The transmission transmits rotary power between the motor shaft and the differential. The multi-speed reduction has an input shaft and at least three on-axis gears. The input shaft is rotatably coupled to the motor shaft. Each of the at least three on-axis gears is co-axial with the input shaft and is rotatable relative to the input shaft in at least one of a first speed ratio and a second speed ratio. The input shaft is axially movable along the axis between a first position, in which a first one of the at least three on-axis gears is rotationally coupled to the input shaft, and a second position in which a second one of the at least three on-axis gears is rotationally coupled to the input shaft.
1. An electric drive axle comprising:
a housing assembly having a housing member, the housing member defining a first bearing mount;
an electric motor coupled to the housing assembly and having a motor shaft that is rotatable about a motor axis;
a differential assembly received in the housing assembly, the differential assembly having a differential input member, which is rotatable about an output axis, and a pair of differential output members that are rotatable about the output axis;
a mounting plate coupled to the housing assembly, the mounting plate defining a second bearing mount; and
a transmission received in the housing assembly and transmitting rotary power between the motor shaft and the differential input member, the transmission having a compound gear that includes a layshaft, a first intermediate gear and a second intermediate gear that are coupled to one another for common rotation about an intermediate axis;
a first bearing received in the first bearing mount and supporting a first end of the layshaft for rotation about the intermediate axis relative to the housing member; and
a second bearing mounted in the second bearing mount and supporting a second end of the layshaft for rotation about the intermediate axis relative to the mounting plate;
wherein a lubrication gallery is formed in the mounting plate, wherein the lubrication gallery is in fluid communication with the first and second bearing mounts.
2. The electric drive axle of claim 1 , wherein a longitudinal passage is formed in the layshaft, and wherein the lubrication gallery is in fluid communication with the longitudinal passage.
3. The electric drive axle of claim 1 , wherein the transmission has a multi-speed reduction that includes an input gear, which is rotatable about an input axis that is parallel to the intermediate axis and drivingly engaged with the first intermediate gear, an intermediate output gear that is rotatable about the input axis and meshingly engaged to the second intermediate gear.
4. The electric drive axle of claim 3 , wherein the multi-speed reduction includes an output gear that is rotatable about the input axis, the output gear being coupled to the intermediate output gear for rotation therewith when the multi-speed reduction is operated in a first speed ratio.
5. The electric drive axle of claim 4 , wherein the output gear is rotatable relative to the intermediate output gear when the multi-speed reduction is operated in a second speed ratio.
6. The electric drive axle of claim 5 , wherein the multi-speed reduction includes an input shaft that is movable along the input axis, the input shaft being coupled to the intermediate input gear for common rotation about the input axis when the multi-speed reduction is operated in the first speed ratio, and the input shaft being coupled and the compound gear, wherein the input shaft being coupled to the output gear for common rotation about the input axis when the multi-speed reduction is operated in the second speed ratio.
7. The electric drive axle of claim 4 , further comprising a third bearing that is received into a bearing mount formed in the mounting plate the third bearing supporting the output gear for rotation about the input axis relative to the mounting plate.
8. The electric drive axle of claim 7 , wherein the lubrication gallery includes a fluid passage that is in fluid connection with the bearing mount in the mounting plate.
9. The electric drive axle of claim 1 , wherein the first intermediate gear extends outwardly of the mounting plate.