Wheel-hub gears and casings therefor

1. A gear casing for a wheel-hub assembly, the gear casing comprising:

a. a gear housing comprising a drive-gear volume for accommodating therewithin a gearing assembly that is positioned to mediate between a drivetrain member and a wheel-hub member, the drive-gear volume being in fluid communication with opposing first and second openings formed in the gear housing for respective gearing-assembly connections therethrough with the drivetrain member and the wheel hub member;

b. a lubricant compartment radially displaced from the drive-gear volume and in fluid communication therewith exclusively via an array of one or more lubricant passages disposed circumferentially around a portion of the gear housing, the lubricant-passage array arranged for flow therethrough of a gearing-assembly lubricant between the lubricant compartment and the gear housing; and

c. a plurality of casing portions, wherein at least one of the gear housing and the lubricant compartment is formed by a joining of at least two of the plurality of casing portions, each of the joined casing portions comprising at least a part of a respective interior surface of at least one of the gear housing and the lubricant compartment.

2. The gear casing of claim 1 , wherein both the gear housing and the lubricant compartment are formed by the joining.

3. The gear casing of claim 1 , wherein the lubricant-passage array is formed exclusively in one joined casing portion.

4. The gear casing of claim 1 , wherein the plurality of casing portions includes a gasket interposed between two other casing portions of the plurality of casing portions, and the lubricant-passage array is formed in the gasket.

5. The gear casing of claim 1 , wherein the lubricant-passage array comprises a plurality of discrete lubricant passages.

6. A gear casing for a wheel-hub assembly, the gear casing comprising:

a. a gear housing comprising a drive-gear volume for accommodating therewithin a gearing assembly that is positioned to mediate between a drivetrain member and a wheel-hub member, the drive-gear volume being in fluid communication with opposing first and second openings formed in the gear housing for respective gearing-assembly connections therethrough with the drivetrain member and the wheel hub member; and

b. a lubricant compartment radially displaced from the drive-gear volume and in fluid communication therewith exclusively via an array of one or more lubricant passages disposed circumferentially around a portion of the gear housing, the lubricant-passage array arranged for flow therethrough of a gearing-assembly lubricant between the lubricant compartment and the gear housing, wherein a bottommost one of the lubricant passages is disposed to be at least in part below a central axis of the gearing assembly, and a topmost one of the lubricant passages is disposed to be at least in part above the central axis of the gearing assembly.

7. The gear casing of claim 6 , wherein at least a part of the bottommost lubricant passage is lower than a lowest part of the drive-gear volume.

8. The gear casing of claim 1 , configured such that all lubricant flows between the lubricant compartment and the gear housing are due to at least one of: (i) forces generated by operation of the gearing assembly; and (ii) external forces acting upon the wheel-hub assembly.

9. A gear casing for a wheel-hub assembly, the gear casing comprising:

a. a gear housing comprising a drive-gear volume for accommodating therewithin a gearing assembly that is positioned to mediate between a drivetrain member and a wheel-hub member, the drive-gear volume being in fluid communication with opposing first and second openings formed in the gear housing for respective gearing-assembly connections therethrough with the drivetrain member and the wheel hub member;

b. a lubricant compartment radially displaced from the drive-gear volume and in fluid communication therewith exclusively via an array of one or more lubricant passages disposed circumferentially around a portion of the gear housing, the lubricant-passage array arranged for flow therethrough of a gearing-assembly lubricant between the lubricant compartment and the gear housing; and

c. a plurality of lubricant compartments radially displaced from the drive-gear volume, each lubricant compartment being in fluid communication therewith exclusively via a respective array of one or more lubricant passages disposed circumferentially around a portion of the gear housing, the respective lubricant-passage being arrays arranged for flow therethrough of a gearing-assembly lubricant between the lubricant compartment and the gear housing.

10. A wheel assembly comprising:

a. a gear casing comprising:

i. a gear housing comprising a drive-gear volume for accommodating therewithin a gearing assembly that is positioned to mediate between a drivetrain member and a wheel-hub member, the drive-gear volume being in fluid communication with opposing first and second openings formed in the gear housing for respective gearing-assembly connections therethrough with the drivetrain member and the wheel hub member;

ii. a lubricant compartment radially displaced from the drive-gear volume and in fluid communication therewith exclusively via an array of one or more lubricant passages disposed circumferentially around a portion of the gear housing, the lubricant-passage array arranged for flow therethrough of a gearing-assembly lubricant between the lubricant compartment and the gear housing;

b. the gearing assembly positioned to mediate between the drivetrain member and the wheel-hub member, the gearing assembly disposed within in the gear casing and comprising a compound planetary gear train comprising (i) a sun gear in bearinged connection with the drivetrain member of the vehicle so as to be rotated thereby, (ii) a carrier in bearinged connection with the wheel-hub member, and (iii) a plurality of composite planet gears each having multiple radii;

c. a sub-frame configured to be mounted to a reference frame of a vehicle;

d. a suspension arm linking the sub-frame to a first connection portion of the gear casing; and

e. a steering system member connected distally to a second connection portion of the gear casing and configured to rotate the wheel-hub member about a steering axis.

11. The wheel assembly of claim 10 , wherein the bearinged connection with the wheel-hub member is via a wheel-hub bearing assembly interiorly attached to the gear casing.

12. The wheel assembly of claim 10 , wherein the planet gears are meshed with a ring gear interiorly attached to the gear casing.

13. A wheel assembly comprising:

a. a drivetrain member and a wheel-hub member, and a gearing assembly coupled to the wheel-hub member and positioned to mediate between the drivetrain member and the wheel-hub member;

b. a gear casing comprising:

i. a gear housing comprising a drive-gear volume for accommodating therewithin the gearing assembly, the drive-gear volume being in fluid communication with opposing first and second openings formed in the gear housing for respective gearing-assembly connections therethrough with the drivetrain member and the wheel hub member;

ii. a lubricant compartment radially displaced from the drive-gear volume and in fluid communication therewith exclusively via an array of one or more lubricant passages disposed circumferentially around a portion of the gear housing, the lubricant-passage array arranged for flow therethrough of a gearing-assembly lubricant between the lubricant compartment and the gear housing;

c. the gearing assembly positioned to mediate between the drivetrain member and the wheel-hub member, the gearing assembly disposed within in the gear casing and comprising a compound planetary gear train comprising (i) a sun gear in bearinged connection with the drivetrain member of the vehicle so as to be rotated thereby, (ii) a carrier in bearinged connection with the wheel-hub member, and (iii) a plurality of composite planet gears each having multiple radii;

d. a brake assembly coupled to the wheel-hub member, the brake assembly being characterized by having a brake caliper connected thereto, wherein a thickness of the gear housing through the drive-gear volume is less than 120% of a width of the brake caliper, the thickness and the width both being in a direction parallel to a central axis of the gearing assembly.

14. The wheel assembly of claim 13 , wherein a thickness of the gearing assembly is less than 110% of a width of the brake caliper, the thickness and the width both being in a direction parallel to a central axis of the gearing assembly.

15. The wheel assembly of claim 13 , wherein the gearing assembly is disposed entirely between the wheel-hub member and a plane defined by an inward-facing rim of a wheel mounted to the wheel-hub member.

16. A vehicle comprising: a pair of opposing wheel assemblies, the wheel assemblies being according to claim 10 ; a corresponding pair of wheels; and the reference frame.

17. The gear casing of claim 1 , wherein a thickness of the lubricant compartment is less than half of a thickness of the gear housing, the thickness of the lubricant compartment and the thickness of the gear housing both being in a direction parallel to a central axis of the gearing assembly.

18. The gear casing of claim 6 , wherein a thickness of the lubricant compartment is less than half of a thickness of the gear housing, the thickness of the lubricant compartment and the thickness of the gear housing both being in a direction parallel to a central axis of the gearing assembly.

19. The gear casing of claim 9 , wherein a thickness of the lubricant compartment is less than half of a thickness of the gear housing, the thickness of the lubricant compartment and the thickness of the gear housing both being in a direction parallel to a central axis of the gearing assembly.

20. The wheel assembly of claim 10 , wherein a thickness of the lubricant compartment is less than half of a thickness of the gear housing, the thickness of the lubricant compartment and the thickness of the gear housing both being in a direction parallel to a central axis of the gearing assembly.

21. The wheel assembly of claim 13 , wherein a thickness of the lubricant compartment is less than half of a thickness of the gear housing, the thickness of the lubricant compartment and the thickness of the gear housing both being in a direction parallel to a central axis of the gearing assembly.

22. The wheel assembly of claim 13 , wherein the bearinged connection with the wheel-hub member is via a wheel-hub bearing assembly interiorly attached to the gear casing.

23. The wheel assembly of claim 13 , wherein the planet gears are meshed with a ring gear interiorly attached to the gear casing.