Axle assembly for low floor vehicle

Patent metadata

Field	Value
Publication number	US-12090858-B2
Application number	US-202217713820-A
Country	US
Kind code	B2
Filing date	Apr 5, 2022
Priority date	Jul 12, 2017
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

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

The invention claimed is:

1. An axle assembly comprising:
an axle housing including a first outer section including a first gearbox, a second outer section including a second gearbox, and a bridge section between the first gearbox and the second gearbox, wherein the bridge section includes a cradle assembly having a cradle frame, a top cover, and a bottom cover that cooperate to define a cradle chamber configured to house an inverter assembly;
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; and
a transmission unit positioned within the first gearbox and configured to transfer torque to the axle shaft, the transmission unit comprising a 2-speed transmission having a shift mechanism for selectively transferring torque to the axle shaft.

2. The axle assembly of claim 1 , 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 for transferring torque to the output assembly.

3. The axle assembly of claim 2 , 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.

4. The axle assembly of claim 3 , 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; and
a drive wheel coupled to an end of the idler shaft;
wherein the shift mechanism is coupled to the idler shaft for selectively transferring torque from the idler shaft to the plurality of idler gears.

5. The axle assembly of claim 4 , wherein the idler shaft is spaced a horizontal distance from the output shaft.

6. The axle assembly of claim 5 , wherein the idler shaft is positioned a vertical distance below the output shaft.

7. The axle assembly of claim 4 , wherein the 2-speed transmission includes 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.

8. The axle assembly of claim 1 , further comprising:
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;
wherein the transmission unit is configured to transfer torque from the electric machine to the axle shaft, wherein the 2-speed transmission is coupled to the drive pinion.

9. The axle assembly of claim 8 , wherein the transmission unit includes a drive wheel configured to mesh with the drive pinion for transferring torque from the electric machine to the axle shaft.

10. The axle assembly of claim 8 , further comprising the inverter assembly positioned within the axle housing and coupled to the electric machine for providing electrical power to the electric machine.

11. The axle assembly of claim 10 , wherein the inverter assembly is positioned within the cradle chamber.

12. The axle assembly of claim 8 , wherein the electric motor is positioned between the drive pinion and the wheel end assembly.

13. The axle assembly of claim 8 , 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.

14. The axle assembly of claim 1 , further comprising:
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; and
a second transmission unit positioned within the second gearbox and configured to transfer torque to the second axle shaft, the second transmission unit comprising a second 2-speed transmission having a second shift mechanism for selectively transferring torque to the second axle shaft.

15. The axle assembly of claim 1 , wherein the first gearbox 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.

Assignees

• Allison Transm Inc

Inventors

• Chopra Vikram
• Baillie Christopher G
• Mepham Shaun

Classifications

• F16H2200/0034

  the gear ratios comprising two forward speeds · CPC title

• F16H2057/02052

  Axle units; Transfer casings for four wheel drive · CPC title

• F16H2057/02034

  Gearboxes combined or connected with electric machines · CPC title

• F16H57/02

  Gearboxes; Mounting gearing therein · CPC title

• F16H3/32

  and an additional shaft · CPC title