Wheel-hub gears and casings therefor

Abstract

A gear casing for a wheel-hub assembly comprises 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 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.

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; 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 pumpless flow therethrough of a gearing-assembly lubricant, substantially die to forces generated by operation of the gearing assembly and/or external forces acting upon the gear casing, between the lubricant compartment and the gear housing.   
     
     
         2 . The gear casing of  claim 1 , comprising 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. 
     
     
         3 . The gear casing of  claim 2 , wherein both the gear housing and the lubricant compartment are formed by the joining. 
     
     
         4 . The gear casing of  claim 2 , wherein the lubricant-passage array is formed exclusively in one joined casing portion. 
     
     
         5 . The gear casing of  claim 2 , 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. 
     
     
         6 . The gear casing of  claim 1 , wherein the lubricant-passage array comprises a plurality of discrete lubricant passages. 
     
     
         7 . The gear casing of  claim 6 , 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. 
     
     
         8 . 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. 
     
     
         9 . The gear casing of  claim 6 , arranged such that a majority of a lubricant-flow through a topmost lubricant passage is from the gear housing to the lubricant compartment. 
     
     
         10 . The gear casing of  claim 1 , configured such that all lubricant flows between the lubricant compartment and the gear housing are due to forces generated by operation of the gearing assembly and/or external forces acting upon the gear casing, and not generated by an oil pump. 
     
     
         11 . The gear casing of  claim 1 , additionally comprising, within the lubricant compartment, a flow-regulation element. 
     
     
         12 . The gear casing of  claim 1 , additionally comprising a first connection portion adapted for connection to a suspension arm of a wheel assembly and a second connection portion adapted for connection to a steering-system member of the wheel assembly. 
     
     
         13 . The gear casing of  claim 1 , comprising 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. 
     
     
         14 - 32 . (canceled) 
     
     
         33 . A wheel assembly comprising:
 a. a gearing assembly comprising a compound planetary gear train configured (i) for a sun gear thereof to be in bearinged connection with a drivetrain member of the vehicle so as to be rotated thereby, and (ii) for a carrier thereof to be in bearinged connection with a wheel-hub member of the vehicle so as to rotate the wheel-hub member, the sun gear and the carrier being rotatably linked by a plurality of composite planet gears each having multiple radii and arranged to rotate the carrier; and   b. a gear casing comprising: (i) a gear housing comprising a drive-gear volume accommodating therewithin the gearing assembly, the gearing assembly 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 (ii) one or more lubricant compartments radially displaced from the drive-gear volume, each one of the one or more lubricant compartments being in fluid communication with the drive-gear volume exclusively via a respective array of one or more lubricant passages disposed circumferentially around a respective portion of the gear housing, each lubricant-passage array arranged for pumpless flow therethrough of a gearing-assembly lubricant, substantially due to forces generated by operation of the gearing assembly and/or external forces acting upon the wheel assembly between the respective lubricant compartment and the gear housing.   
     
     
         34 . The wheel assembly of  claim 33 , additionally comprising the wheel-hub member, 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. 
     
     
         35 . The wheel assembly of  claim 33 , wherein the lubricant compartment is not in communication with a lubricant pump. 
     
     
         36 . The wheel assembly of  claim 1 , wherein the lubricant compartment is not in communication with a lubricant pump.