Axle assembly for low floor vehicle

Patent metadata

Field	Value
Publication number	US-11292332-B2
Application number	US-201816630757-A
Country	US
Kind code	B2
Filing date	Jul 12, 2018
Priority date	Jul 12, 2017
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

An axle assembly for a low floor vehicle is described herein. The axle assembly includes an axle housing and a drive unit for driving a wheel assembly. The drive unit includes an axle shaft, a wheel end assembly, an electric machine, and a transmission unit. The axle shaft extends along an axle centerline axis between a first axle end and a second axle end. The wheel end assembly is coupled to the first axle end. The electric machine is positioned within the axle housing and includes a rotor shaft, a drive pinion coupled to the rotor shaft, and an electric motor for rotating the rotor shaft. The rotor shaft extends along a rotor shaft centerline axis that is orientated parallel to the axle centerline axis. The transmission unit is positioned within the axle housing and is configured to transfer torque from the electric machine to the axle shaft.

First claim

What is claimed is:

1. An axle assembly comprising:
an axle housing including a first gearbox, a second gearbox, and a bridge section between the first gearbox and the second gearbox; and
a drive unit for driving a wheel assembly, the drive unit including:
an axle shaft extending along an axle centerline axis between a first axle end and a second axle end with the second axle end disposed within the axle housing;
a wheel end assembly coupled to the first axle end spaced from the axle housing;
an electric machine positioned within the first gearbox and including a rotor shaft, a drive pinion coupled to the rotor shaft, and an electric motor for rotating the rotor shaft, the rotor shaft extending along a rotor shaft centerline axis orientated parallel to the axle centerline axis; and
a transmission unit positioned within the first gearbox and configured to transfer torque from the electric machine to the axle shaft, the transmission unit including:
an output assembly coupled to the second axle end such that a rotation of the output assembly rotates the axle shaft; and
an offset gear reduction assembly coupled to the output assembly and the drive pinion of the electric machine for transferring torque from the electric machine to the output assembly.

2. The axle assembly of claim 1 , wherein the electric motor is positioned between the drive pinion and the wheel end assembly.

3. The axle assembly of claim 1 , wherein the rotor shaft extends along the rotor shaft centerline axis away from the electric motor in a first direction, and the axle shaft extends along the axle centerline axis away from the axle housing in a second direction with the first direction being opposite to the second direction.

4. The axle assembly of claim 1 , wherein the output assembly includes:
an output shaft coupled to the second axle end and orientated co-axially with the axle shaft; and
a plurality of output gears fixedly coupled to the output shaft.

5. The axle assembly of claim 4 , wherein the offset gear reduction assembly includes: an idler shaft orientated substantially parallel with the output shaft;
a plurality of idler gears rotatably coupled to the idler shaft, each idler gear configured to mesh with a corresponding output gear such that a rotation of an idler gear causes a rotation of the corresponding output gear;
a shift mechanism coupled to the idler shaft for selectively transferring torque from the idler shaft to the plurality of idler gears; and
a drive wheel coupled to an end of the idler shaft, the drive wheel configured to mesh with the drive pinion for transferring torque from the electric machine to the idler shaft.

6. The axle assembly of claim 5 , wherein the idler shaft is spaced a horizontal distance from the rotor shaft.

7. The axle assembly of claim 6 , wherein the idler shaft is positioned a vertical distance below the output shaft and the rotor shaft.

8. The axle assembly of claim 5 , wherein the transmission unit includes a 2-speed transmission including the plurality of output gears including a first output gear and a second output gear spaced along the output shaft, the plurality of idler gears includes a first idler gear meshed with the first output gear and a second idler gear meshed with the second output gear.

9. The axle assembly of claim 1 , further comprising an inverter assembly positioned within the axle housing and coupled to the electric machine for providing electrical power to the electric machine.

10. The axle assembly of claim 1 , further comprising
a second drive unit for driving a second wheel assembly, the second drive unit

including: a second axle shaft extending along the axle centerline axis;
a second wheel end assembly coupled to the second axle shaft and spaced from the second gearbox;
a second electric machine positioned within the second gearbox; and
a second transmission unit positioned within the second gearbox and configured to transfer torque from the second electric machine to the second axle shaft, the transmission unit including: a second output assembly coupled to the second axle shaft such that a rotation of the second output assembly rotates the second axle shaft; and
a second offset gear reduction assembly coupled to the second output assembly and the second electric machine for transferring torque from the second electric machine to the second output assembly.

11. The axle assembly of claim 1 , wherein the bridge section includes a cradle assembly including an inner surface defining a support chamber.

12. The axle assembly of claim 11 , further comprising an inverter assembly positioned within the support chamber and coupled to the electric machine.

13. An axle housing for use with an axle assembly including a drive unit including an axle shaft, an electric machine, a transmission unit coupled to the axle shaft and the electric machine, the axle housing comprising:
a first outer section, a second outer section, and a bridge section extending between the first outer section and the second outer section;
the first outer section including a gearbox including an inner surface that defines a cavity configured to receive the electric machine and the transmission unit therein, the axle shaft extending outwardly from the first outer section; and
the bridge section including a cradle assembly coupled to the gearbox, the cradle assembly including an inner surface that defines a support chamber.

14. The axle housing of claim 13 , wherein the axle assembly includes a second drive unit, the second outer section includes a second gearbox coupled to the cradle assembly and configured to support the second drive unit therein.

15. The axle housing of claim 13 , wherein the gearbox housing includes:
a body extending between a first endwall and an opposite second endwall;
a pair of first support flanges extending outwardly from the first endwall, the pair of first support flanges configured to couple to a first mount arm coupled to a vehicle frame; and
a pair of second support flanges extending outwardly from the second endwall, the pair of second support flanges configured to couple to a second mount arm coupled to the vehicle frame.

16. The axle housing of claim 13 , wherein the axle shaft extends along an axle centerline axis between a first axle end and a second axle end with the second axle end disposed within the gearbox; and
wherein a wheel end assembly is coupled to the first axle end spaced from the gearbox.

17. The axle housing of claim 16 , wherein the electric machine includes a rotor shaft, a drive pinion coupled to the rotor shaft, and an electric motor for rotating the rotor shaft, the rotor shaft extending along a rotor shaft centerline axis orientated parallel to the axle centerline axis.

18. The axle housing of claim 17 , wherein the rotor shaft extends along the rotor shaft centerline axis away from the electric motor in a first direction, and the axle shaft extends along the axle centerline axis away from the gearbox in a second direction with the first direction being opposite to the second direction.

19. The axle housing of claim 17 , wherein the transmission unit includes:
an output assembly coupled to the second axle end such that a rotation of the output assembly rotates the axle shaft; and
an offset gear reduction assembly coupled to the output assembly and the drive pinion of the electric machine for transferring torque from the electric machine to the output assembly.

20. The axle housing of claim 19 , wherein the offset ge

Assignees

• Allison Transm Inc

Inventors

• Mepham Shaun
• Chopra Vikram
• Baillie Christopher G

Classifications

• F16H2200/0034

  the gear ratios comprising two forward speeds · CPC title

• B60K17/043

  Transmission unit disposed in on near the vehicle wheel, or between the differential gear unit and the wheel · CPC title

• B60K2007/0061

  the motor axle being parallel to the wheel axle · CPC title

• F16H3/32

  and an additional shaft · CPC title

• B60K7/0007 Primary

  the motor being electric · CPC title