Lubrication system for an axle assembly

1 . An axle assembly for a vehicle, comprising:

a differential including a drive gear rotatable about an axis and a differential case coupled with and radially inboard of the drive gear and defining a gear interaction space extending axially between a first axial position and a second axial position; and

a housing that includes a differential portion having a proximal portion in which the drive gear is housed, a first distal portion extending in a first axial direction from the proximal portion, and a second distal portion extending in a second axial direction from the proximal portion, wherein the differential portion defines:

a sump in the proximal portion and disposed radially outboard of the drive gear;

a cavity in the proximal portion and radially opposite of the sump;

a first chamber extending in the first axial direction to a third axial position spaced distally from the first axial position; and

a second chamber extending in the second axial direction to a fourth axial position spaced distally from the second axial position,

wherein the differential portion and the differential form a fluid flow path extending from the sump, circumferentially between the drive gear and the proximal portion and to the cavity, from the cavity in the first axial direction into the first chamber, and from the first chamber in the second axial direction into the gear interaction space, and from the gear interaction space into the second chamber.

2 . The axle assembly of claim 1 , wherein the proximal portion and the drive gear define an outer space therebetween, wherein rotation of the drive gear causes fluid in the sump to move through the outer space and into the cavity.

3 . The axle assembly of claim 1 , comprising:

a catcher ring adjacent to the differential case, wherein the differential case defines a passage through which the fluid flow path extends between the first chamber and the gear interaction space, wherein the catcher ring comprises:

a tube that engages the passage and provides an entry into the passage from the first chamber.

4 . The axle assembly of claim 1 , wherein the differential portion is configured to be supported by the vehicle in an orientation such that the sump is disposed below the axis for collecting fluid.

5 . The axle assembly of claim 4 , comprising:

a motor; and

a drive portion coupled with the differential portion and in which a gear assembly is disposed, wherein operation of the motor causes rotation of the differential via operation of the gear assembly.

6 . The axle assembly of claim 5 , wherein the differential portion and the drive portion cooperate to form a floor and a ceiling opposite the floor, and comprising:

a guide extending circumferentially from the floor about the axis between the drive portion and the differential portion.

7 . The axle assembly of claim 1 , wherein the first chamber narrows from the cavity to a first distal end and the second chamber narrows from the cavity to a second distal end.

8 . The axle assembly of claim 7 , wherein the differential portion includes a ledge extending from the first distal end and tapering toward the differential case to guide fluid radially inwardly in the second axial direction to the differential case.

9 . The axle assembly of claim 1 , wherein a first plane passes through the axis, the sump, and the cavity, and wherein a second plane is orthogonal to the first plane and passes through the axis, the second plane dividing the differential portion into a first side in which the sump is disposed and a second side in which the cavity, the first chamber, and the second chamber are disposed.

10 . The axle assembly of claim 9 , wherein the differential portion includes a first protruding portion radially opposite the first chamber and a second protruding portion radially opposite the second chamber, each protruding portion disposed on the first side of the differential portion.

11 . The axle assembly of claim 10 , wherein the first and second protruding portions define axial limits of the sump such that oil in the sump is configured to move out of the sump via circumferential displacement.

12 . An axle assembly, comprising:

a motor;

a differential including a drive gear rotatable about an axis and a differential case radially inboard of the drive gear defining a gear interaction space inside the differential case and extending between a first axial position and a second axial position;

a gear assembly operably coupled with the motor; and

a housing including:

a drive portion in which the gear assembly is disposed, wherein operation of the motor causes rotation of the differential via operation of the gear assembly; and

a differential portion having a proximal portion in which the drive gear is housed, wherein the proximal portion and the drive gear define an outer space therebetween, wherein rotation of the drive gear causes fluid in the sump to move through the outer space and into the cavity, wherein the differential portion defines:

a sump in the proximal portion and disposed radially outboard of the drive gear;

a cavity in the proximal portion and radially opposite of the sump;

a first chamber extending from the cavity in a first axial direction to a third axial position spaced distally from the first axial position; and

a second chamber extending from the cavity in a second axial direction to a fourth axial position spaced distally from the second axial position,

wherein the differential portion and the differential form a fluid flow path extending from the sump, circumferentially between the drive gear and the proximal portion and to the cavity, from the cavity in the first axial direction into the first chamber, and from the first chamber in the second axial direction into the gear interaction space, and wherein the drive gear has teeth that extend radially outwards from the outer circumference of the drive gear and that divide the outer space into segments, such that when the drive gear rotates, the segments rotate and move the fluid.

13 . The axle assembly of claim 12 , comprising:

a catcher ring adjacent to the differential case, wherein the differential case defines a passage through which the fluid flow path extends between the first chamber and the gear interaction space, wherein the catcher ring partially engages the passage.

14 . The axle assembly of claim 12 , wherein the differential portion includes a first distal portion extending in a first axial direction from the proximal portion and a second distal portion extending in a second axial direction from the proximal portion, wherein the first chamber narrows from the cavity toward a first distal end and the second chamber narrows from the cavity toward a second distal end.

15 . The axle assembly of claim 14 , wherein the differential portion includes a ledge extending from the first distal end and tapering toward the differential case to guide fluid radially inwardly in the second axial direction to the differential case.

16 . The axle assembly of claim 12 , wherein a first plane passes through the axis, the sump, and the cavity, and wherein a second plane is orthogonal to the first plane and passes through the axis, the second plane dividing the differential portion into a first side in which the sump is disposed and a second side in which the cavity, the first chamber, and the second chamber are disposed.

17 . The axle assembly of claim 16 , wherein the differential portion includes a first protruding portion radially opposite the first chamber and a second protruding portion radially opposite the second chamber, each of the protruding portions disposed on the first side of the differential portion, and wherein the first protruding portion and the second protruding portion extend substantially orthogonal to the axis.

18 . The axle assembly of claim 17 , wherein the first and second protruding portions define axial limits of the sump such that oil in the sump is configured to move into or out of the sump via circumferential displacement.

19 . An axle assembly for a vehicle, comprising:

a differential including a drive gear rotatable about an axis and a differential case coupled with the drive gear and defining a gear interaction space inside the differential case; and

a housing in which the drive gear is housed and including a ledge, the housing defining:

a sump disposed radially outboard of the drive gear;

a cavity opposite the sump; and

a chamber extending in a first axial direction and narrowing from the cavity toward a distal end of the housing, wherein the ledge extends from the distal end and tapers radially inwardly in a second axial direction opposite the first axial direction from the distal end toward the differential case to guide fluid toward the differential case.

20 . The axle assembly of claim 19 , wherein the housing is formed of a differential portion and a drive portion, and wherein the differential portion and the drive portion cooperate to form a floor and a ceiling opposite the floor, and wherein the axle assembly further comprises:

a guide extending circumferentially from the ceiling in the drive portion, and wherein the second guide defines a void in which oil can accumulate after being carried by the drive gear.