Fluid distribution apparatus and the axle assembly made therewith

A fluid distribution apparatus for an axle assembly, the fluid distribution apparatus including a cylindrical portion rotatably disposed about a bearing race. A conical portion is coupled with the cylindrical portion, and a retaining portion is coupled with the conical portion. A plurality of circumferentially spaced tubes are coupled with the retaining portion, wherein the tubes are at least partially disposed through a rotating component of a clutch.

FIELD

The presently disclosed subject matter relates to an axle assembly, and more particularly to a fluid distribution apparatus for an axle assembly.

BACKGROUND

The present subject matter relates to fluid distribution in a drive unit assembly. An axle assembly drive unit assembly may include one or more clutch assemblies to transmit drive force. Insufficient fluid flow in a drive unit assembly may cause thermal failure in a drive unit clutch assembly and other drive unit components.

It would be desirable to produce a drive unit assembly having increased fluid distribution efficacy.

SUMMARY

In concordance and agreement with the present disclosure, a fluid distribution apparatus for an axle assembly, which enhances fluid distribution efficiency of a drive unit assembly, has surprisingly been discovered.

In one embodiment, a fluid distribution apparatus, comprises: a main body; a conical neck portion coupled with the main body; and a retaining portion coupled with the conical neck portion, wherein the retaining portion includes at least one tube coupled thereto, the at least one tube configured to receive a fluid therethrough.

As aspects of certain embodiments, the main body is configured to be disposed about a bearing.

As aspects of certain embodiments, the at least one tube is at least partially disposed through a rotating component of a clutch.

As aspects of certain embodiments, the at least one tube includes a locking element disposed thereon.

As aspects of certain embodiments, the locking element abuts a first surface of the rotating component of the clutch.

As aspects of certain embodiments, a surface of the retaining portion abuts a second surface of the rotating component of the clutch opposite the first surface thereof.

As aspects of certain embodiments, a portion of an inner surface of the at least one tube is substantially continuous with an inner surface of the retaining portion.

In another embodiment, a clutch assembly, comprises: a clutch drum; at least one clutch hub at least partially disposed within the clutch drum; a plurality of first clutch plates movably coupled with a portion of the clutch drum; at least one bearing disposed adjacent at least one of the clutch drum and the at least one clutch hub; and a fluid distribution apparatus configured to permit fluid communication between the bearing and the first clutch plates.

As aspects of certain embodiments, the clutch assembly further comprises a bearing retainer plate disposed adjacent the at least one clutch hub.

As aspects of certain embodiments, the fluid distribution apparatus is rotatable with at least one of the clutch drum and the bearing retainer plate.

As aspects of certain embodiments, a plurality of apertures is formed in at least one of the clutch drum and the bearing retainer plate.

As aspects of certain embodiments, a portion of the fluid distribution apparatus is disposed through the apertures formed in the at least one of the clutch drum and the bearing retainer plate.

As aspects of certain embodiments, at least one of the clutch drum and the clutch hub is formed by a center portion, a wall portion coupled with the center portion, and cylindrical portion coupled with the wall portion.

In yet another embodiment, an axle assembly, comprises: a clutch drum including a center portion, a wall portion coupled to the center portion, and a cylindrical portion coupled to the wall portion, wherein a plurality of first apertures is formed in the clutch drum; a first clutch hub at least partially disposed within the clutch drum about a first shaft; a second clutch hub at least partially disposed within the clutch drum about a second shaft; a first bearing disposed adjacent the first clutch hub about the first shaft; a second bearing disposed adjacent the second clutch hub about the second shaft; a bearing retainer plate disposed adjacent at least one of the first bearing and the first clutch hub, wherein a plurality of second apertures is formed in the bearing retainer plate; a first clutch pack at least partially disposed between the first clutch hub and the clutch drum; a second clutch pack at least partially disposed between the second clutch hub and the clutch drum; and a first fluid distribution apparatus disposed between one of the bearings and one of the clutch packs, wherein the first fluid distribution apparatus is configured to permit fluid communication between the one bearings and the one of the clutch packs.

As aspects of certain embodiments, the axle assembly further comprises a second fluid distribution apparatus disposed between another one of the bearings and another one of the clutch packs, wherein the second fluid distribution apparatus is configured to permit fluid communication between the another one of the bearings and the another one of the clutch packs.

DETAILED DESCRIPTION

It is to be understood that the presently disclosed subject matter may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific assemblies and systems illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. Also, although they may not be, like elements in various embodiments described herein may be commonly referred to with like reference numerals within this section of the application.

As illustrated inFIG. 1, a vehicle constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral10. In an embodiment, the vehicle10may be a hybrid-electric all-wheel-drive vehicle, where a first axle assembly12is driven by an internal combustion engine14, and a second axle assembly16is driven by an electric motor/generator18. The first axle assembly12may transmit torque from the power source14to a pair of front wheels116L,116R. The second axle assembly16may selectively transmit torque from the electric motor/generator18to a pair of rear wheels114L,114R.

In another embodiment, not depicted, the second axle assembly16is utilized with a pure electric vehicle where the second axle assembly16is the only driving axle. In still other embodiments, not depicted, the second axle assembly16is utilized in a hybrid electric commercial vehicle comprising a tandem axle in which the front tandem axle is driven by an internal combustion engine, and the rear tandem axle is the second axle assembly16(or vice versa). The second axle assembly16may have applications in commercial vehicles, both light duty and heavy-duty vehicles, and for passenger, off-highway, and sport utility vehicles. Additionally, the second axle assembly16described herein may be adapted for use in front and/or rear driving axles, and in steerable and non-steerable axles. It would be understood by one of ordinary skill in the art that the second axle assembly16also has industrial, locomotive, military, agricultural, and aerospace applications.

As illustrated inFIG. 1A, another vehicle constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral100. The vehicle100may comprise a hybrid-electric powertrain102having all-wheel drive functionality. The powertrain102may include a power source104having an output driveably connected with a transmission106. The power source104may be, but is not limited to, an internal combustion engine or an electric motor. The powertrain102may include a first axle assembly110and a second axle assembly112. In one embodiment, as illustrated inFIG. 1A, the first axle assembly110comprises a power transfer unit108driveably connected with an output of the transmission106. The first axle assembly110is driveably connected with the transmission106and may continuously transmit torque from the power source104to a pair of front wheels116L,116R. The second axle assembly112may selectively transmit torque from the power source104to a pair of rear wheels114L,114R via the power transfer unit108. The second axle assembly112may include a drive unit assembly120.

As illustrated inFIG. 2, in an embodiment, the second axle assembly16includes the electric motor/generator18providing torque to a planetary gear assembly122. The planetary gear assembly122outputs torque to a first gear124. In an embodiment, the first gear124may be a helical gear. The first gear124may be in meshed engagement with a second gear126. In an embodiment, the second gear126may be a helical ring gear. The second gear126transmits torque to a differential mechanism128. In an embodiment, as illustrated inFIG. 2, the differential mechanism128may comprise a dual-clutch differential mechanism. The second gear126is coupled with a clutch drum144(described in additional detail intra) of the differential mechanism128. The second gear126may be coupled with the clutch drum144via welding, an interference fit, or spline engagement, but is not limited to these methods of coupling.

In an embodiment, as illustrated inFIGS. 2-5, the differential mechanism128may comprise a first wet clutch assembly130and a second wet clutch assembly230. The first wet clutch assembly130may comprise a clutch hub132. As illustrated inFIG. 3, the clutch hub132may comprise an axially extending generally cylindrical center portion134having a splined internal surface136. The splined internal surface136of the clutch hub132may be in meshed engagement with a spline on a stub shaft139that is coupled with the wheel114R. In an embodiment, as illustrated inFIGS. 2 and 4, the clutch hub132may be formed unitary and integral with the stub shaft139. The clutch hub132may also comprise a radially extending wall portion138coupled with the inboard end of the center portion134. In certain embodiments, the wall portion138may be formed unitary with the center portion134. An axially extending cylindrical portion140may be coupled at its inboard end with a radially outer surface of the wall portion138. In an embodiment, the cylindrical portion140may be formed unitary with the wall portion138. An outer surface of the cylindrical portion140comprises a plurality of axially extending splines142.

The cylindrical portion140of the clutch hub132is disposed concentric and coaxial with the wall portion138and the center portion134. As illustrated inFIGS. 2-4, in an embodiment, the clutch hub132may be located at least partially concentric with and radially inside the clutch drum144.

The clutch drum144may be disposed about and coupled with an axle half shaft137for rotation relative thereto. The clutch drum144may comprise an axially extending center portion145including a cylindrical interior surface having a clearance fit about a portion of the axle half shaft137. In an embodiment, not depicted, a bushing may be disposed between the center portion145of the clutch drum144and the axle half shaft137. In another embodiment, the axle half shaft137may comprise an integral bushing portion that has been machined and/or heat treated to provide a surface for rotation relative to the clutch drum144.

The clutch drum144may further comprise a radially extending discoid wall portion146. The wall portion146may be coupled with, and may be unitary with, the center portion145. The clutch drum144may additionally comprise an axially extending cylindrical portion147. The cylindrical portion147may be coupled with, and may be unitary with, the wall portion146. The cyclindrical portion147is disposed radially about, and comprises a portion of, both the first and second wet clutch assemblies130,230. A plurality of axially extending splines148may be formed on an internal surface of the cylindrical portion147.

A first set of clutch plates150, more clearly shown inFIG. 3, may be disposed in splined engagement with the splines142of clutch hub132for selective axial movement thereon. The first set of clutch plates150may include a plurality of splines or teeth on a radially internal surface thereof for engagement with the splines142. The first set of clutch plates150extend radially outward from the clutch hub132.

A second set of clutch plates152may be disposed in splined engagement with the splines148of the cylindrical portion147of the clutch drum144for selective axial movement therein. The second set of clutch plates152may include a plurality of splines or teeth on a radially external surface thereof for engagement with the splines148. The second set of clutch plates152extends radially inward from the cylindrical portion147of the clutch drum144. The individual plates from the second set of clutch plates152are interleaved with the individual plates from the first set of clutch plates150. The first and second set of clutch plates150,152comprise a clutch pack.

The first set of clutch plates150can be selectively frictionally engaged with the second set of clutch plates152when the plates150,152are compressed together. The axial compression of the plates150,152may be facilitated via a linear actuator154(shown inFIGS. 3 and 4). In an embodiment, as illustrated inFIG. 3, the linear actuator154may be a ball and ramp type actuator driven by an electric motor (not depicted). In other embodiments, not depicted, the linear actuator154may comprise a hydraulic driven piston or an electromagnetic actuator. The linear actuator154may comprise a thrust plate156having a plurality of axially extending cylindrical protrusions158.

In an embodiment, as illustrated inFIG. 3, a sleeve160may be coupled with the cylindrical portion134of the clutch hub132. A bearing retainer plate162may be at least partially concentrically disposed about and coupled with the stub shaft139shown inFIGS. 2 and 4. In an embodiment, as illustrated inFIG. 3, the bearing retainer plate162may be coupled with the sleeve160. The bearing retainer plate162is disposed axially adjacent to the clutch hub132. In an embodiment, as illustrated inFIG. 4, a bushing304may be disposed about the stub shaft139axially between the bearing retainer plate162and the clutch hub132. In an embodiment, the bearing retainer plate162may define a recess306in which the bushing304is at least partially disposed. In an embodiment, the bushing304may be a thrust bearing.

In the embodiment shown inFIG. 3, the bearing retainer plate162may comprise discoid portion164radially extending from an inboard end of a cylindrical neck166. The discoid portion164may define a first plurality of apertures (not depicted) extending axially therethrough. The cylindrical protrusions158of the thrust plate156may be disposed through the first plurality of apertures in the bearing retainer plate162and abut a first pressure plate168A. The first pressure plate168A is selectively moved in an axial direction by the linear actuator154to frictionally engage the clutch pack150,152between the first pressure plate168A and a second pressure plate168B.

A tapered roller bearing170may be coupled with the cylindrical neck166of the bearing retainer plate162to position and rotatably support the clutch hub132within the drive unit assembly120. As illustrated inFIG. 3, one of a pair of fluid distribution apparatuses172may be disposed at least partially about a radially outer surface174of an outer race of the tapered roller bearing170. As illustrated inFIGS. 3 and 6-9, in an embodiment, the fluid distribution apparatus172may comprise a main body176. The main body176may have a generally hollow cylindrical geometry defined by a radially inner surface178and a radially outer surface180. In certain embodiments, the radially inner surface178of the main body176is disposed on the outer surface174of the tapered roller bearing170via a clearance fit such that the fluid distribution apparatus172may rotate freely about the tapered roller bearing170.

The fluid distribution apparatus172also comprises a retaining portion182coupled with the main body176via a conical neck portion184. In an embodiment, the angle between the conical neck portion184and the axis of rotation of the fluid distribution apparatus172may be a function of the geometry of the tapered roller bearing170and the geometry of the bearing retainer plate162(or the clutch drum144as discussed intra). The retaining portion182may comprise a generally annular discoid geometry defining a radially inner surface185. In assembly, as illustrated inFIGS. 2-5, an inboard surface186of the retaining portion182abuts an outboard surface188of the discoid portion164of the bearing retainer plate162.

The fluid distribution apparatus172further comprises a plurality of tubes190coupled with the inboard surface186of the retaining portion182. In an embodiment, the tubes190may be disposed circumferentially equidistant about the retaining portion182. The tubes190shown have a hollow-cylindrical geometry defining a radially inner surface192and a radially outer surface194. In an embodiment3shown inFIGS. 6-9, a portion of the radially inner surface192of the tubes190may be substantially continuous (i.e. flush) with the radially inner surface185of the retaining portion182. As illustrated inFIG. 3, the tubes190are disposed through apertures196in the discoid portion164of the bearing retainer plate162. Accordingly, the tubes190are fixed for rotation with the bearing retainer plate162. In addition, each of the tubes190may include a locking element198coupled with the radially outer surface194. The locking elements198engage an inboard surface200of the discoid portion164of the bearing retainer plate162to prevent the tubes190of the fluid distribution apparatus172from moving outboard during operation. The radially inner surface192of the tubes190define fluid conduits201.

In an embodiment, as illustrated inFIGS. 2, 4, and 5, the second wet clutch assembly230may comprise a clutch hub232. As illustrated inFIG. 5, the clutch hub232may comprise an axially extending generally cylindrical center portion234having a splined internal surface236. The splined internal surface236of the clutch hub232may be in meshed engagement with a spline on the axle half shaft137that is coupled with the wheel114L. The clutch hub232may also comprise a radially extending wall portion238coupled with the inboard end of the center portion234. In certain embodiments, the wall portion238may be formed unitary with the center portion234. An axially extending cylindrical portion240may be coupled at its inboard end with a radially outer surface of the wall portion238. In an embodiment, the cylindrical portion240may be formed unitary with the wall portion238. An outer surface of the cylindrical portion240comprises a plurality of axially extending splines242.

In an embodiment, as illustrated inFIG. 4, the center portion234of the clutch hub232may define a recess308. A portion of the inboard end of the stub shaft139may be at least partially disposed within the recess308. A bushing310may be disposed radially between the inboard end of the stub shaft139and the center portion234of the clutch hub232. In an embodiment, the bushing310may be a needle bearing.

The cylindrical portion240of the clutch hub232is disposed coaxial with the wall portion238and the center portion234. As illustrated inFIGS. 2-4, in an embodiment, the clutch hub232may be located at least partially concentric with and radially inside the clutch drum144.

The clutch drum144may be disposed about and coupled with an axle half shaft137for rotation relative thereto. A bushing300may be disposed about the axle half shaft137axially between the wall portion146of the clutch drum144and the clutch hub232. In an embodiment, as illustrated inFIG. 5, the wall portion146of the clutch drum144may define a recess302in which the bushing300may be at least partially disposed. In an embodiment, the bushing300may be a thrust bearing.

A first set of clutch plates250may be disposed in splined engagement with the splines242of the clutch hub232for selective axial movement thereon. The first set of clutch plates250may include a plurality of splines or teeth on an radially internal surface thereof for engagement with the splines242of the clutch hub232. The first set of clutch plates250extend radially outward from the clutch hub232.

A second set of clutch plates252may be disposed in splined engagement with the splines148of the cylindrical portion147of the clutch drum144for selective axial movement therein. The second set of clutch plates252may include a plurality of splines or teeth on a radially external surface thereof for engagement with the splines148. The second set of clutch plates252extends radially inward from the cylindrical portion147of the clutch drum144. The individual plates from the second set of clutch plates252are interleaved with the individual plates from the first set of clutch plates250. The first and second set of clutch plates250,252comprise a clutch pack.

The first set of clutch plates250can be selectively frictionally engaged with the second set of clutch plates252when the plates250,252are compressed together. The axial compression of the plates250,252may be facilitated via a linear actuator254(more clearly shown inFIG. 5). In an embodiment, the linear actuator254may be a ball and ramp type actuator driven by an electric motor (not depicted). In other embodiments, not depicted, the linear actuator254may comprise a hydraulic driven piston or an electromagnetic actuator. The linear actuator254may comprise a thrust plate256having a plurality of axially extending cylindrical protrusions258.

The discoid wall portion146of the clutch drum144may define a first plurality of apertures149extending axially therethrough. The cylindrical protrusions258of the thrust plate256may be disposed through the first plurality of apertures149in the discoid wall portion146and abut a first pressure plate268A. The first pressure plate268A is selectively moved in an axial direction by the linear actuator254to frictionally engage the clutch pack250,252between the first pressure plate268A and a second pressure plate268B.

A tapered roller bearing270may be coupled with the center portion145of the clutch drum144to position and at least partially rotatably support the clutch drum144within the housing of the second axle assembly16. As illustrated inFIG. 5, another one of the fluid distribution apparatuses172may be disposed at least partially about a radially outer surface of an outer race of the tapered roller bearing270. In assembly shown inFIG. 5, the inboard surface186of the retaining portion182of the fluid distribution apparatus172abuts an outboard surface288of the wall portion146of the clutch drum144. The tubes190of the fluid distribution apparatus172are disposed through apertures296formed in the wall portion146of the clutch drum144. Because the tubes190are disposed through the apertures296, the fluid distribution apparatus172is fixed for rotation with the clutch drum144. In addition, the locking element198of the tubes190engage an inboard surface289of the wall portion146of the clutch drum144to prevent the tubes190from moving outboard during operation.

During operation of the second axle assembly16, rotation of the outer race of the tapered roller bearings170,270pumps a fluid such as a lubricant, for example, from within the axle housing through the tapered roller bearings170,270into the fluid distribution apparatuses172. Because the fluid distribution apparatuses172are rotating, the fluid therein experiences a centrifugal force from the rotation. The fluid also experiences a normal force when in contact with the conical neck portion184of the fluid distribution apparatuses172. The combination of the centrifugal force and the normal force acting on the fluid facilitates travel of the fluid through the main body176and the conical neck portion184of the fluid distribution apparatuses172to the retaining plate182. A portion of the axial travel of the fluid is halted by the retaining portion182of the fluid distribution apparatuses172. Another portion of the fluid travels into the tubes190of the fluid distribution apparatuses172. The fluid passes through the fluid conduits201of the fluid distribution apparatuses172to the clutch plates150,152of the first wet clutch assembly130and to the clutch plates250,252of the second wet clutch assembly230.

While various embodiments have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant arts that the disclosed subject matter may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments described above are therefore to be considered in all respects as illustrative, not restrictive.