Patent Description:
A drivetrain assembly having a shift mechanism that includes a sector cam is disclosed in <CIT>.

<CIT> discloses, in the opinion of the Examining Division of the European Patent Office, an axle assembly comprising: a first shaft that is rotatable about a first axis; a first set of gears that is rotatable about the first axis; and a second set of gears that is rotatable about a second axis, wherein each member of the second set of gears meshes with a different member of the first set of gears; a first shift collar that is rotatable about the first axis with the first shaft and moveable along the first axis with respect to the first shaft to selectively connect a member of the first set of gears to the first shaft; and a barrel cam that is rotatable about a barrel cam axis that is disposed substantially parallel to the first axis and operatively connected to the first shift collar, wherein rotation of the barrel cam about the barrel cam axis controls movement of the first shift collar along the first axis, wherein the first shift fork is slidable along a shift rail that is spaced apart from the barrel cam and that extends substantially parallel to the barrel cam axis, wherein the shift rail extends along a shift rail axis that is disposed substantially parallel to the barrel cam axis, wherein the shift rail axis is disposed closer to the first axis and the second axis than the barrel cam axis is disposed to the first axis and the second axis, the axle assembly further comprising a second shaft that is rotatable about a second axis; and a second shift collar that is rotatable about the second axis with the second shaft and moveable along the second axis with respect to the second shaft to selectively connect a member of the second set of gears to the second shaft wherein the barrel cam is operatively connected to the second shift collar, wherein rotation of the barrel cam about the barrel cam axis controls movement of the second shift collar along the second axis.

<CIT> discloses a transmission that has multiple clutchable gears disposed on a primary shaft and the secondary shaft.

An axle assembly is provided as disclosed in claim <NUM>.

The axle assembly <NUM> may be provided with a vehicle like a truck, bus, farm equipment, mining equipment, military transport or weaponry vehicle, or cargo loading equipment for land, air, or marine vessels. The vehicle may include a trailer for transporting cargo in one or more embodiments.

The axle assembly <NUM> may provide torque to one or more traction wheel assemblies that may include a tire <NUM> mounted on a wheel <NUM>. The wheel <NUM> may be mounted to a wheel hub that may be rotatable about a wheel axis <NUM>.

The axle assembly <NUM> may include or may be operatively connected to a torque source <NUM>. The torque source <NUM> may be of any suitable type. For instance, the torque source <NUM> may be a non-electrical torque source, an electrical torque source, or combinations thereof. An example of a non-electrical torque source is an internal combustion engine. An example of an electrical torque source is an electric motor <NUM>. An electric motor <NUM> may include a stator <NUM> and a rotor <NUM> that may be rotatable about an axis. An electrical power source <NUM> such as a battery, capacitor, generator, or the like, may be electrically connected to an electric motor <NUM> in a manner known by those skilled in the art.

In at least one configuration, the axle assembly <NUM> may include a differential assembly <NUM>, at least one axle shaft <NUM>, and a transmission <NUM>. The axle assembly <NUM> may also include a shift mechanism <NUM> as shown in <FIG>.

Referring to <FIG>, the differential assembly <NUM> may transmit torque to the vehicle traction wheel assemblies and permit the traction wheel assemblies to rotate at different velocities. In addition, the differential assembly <NUM> may be operatively connected to the axle shafts <NUM> and may permit the axle shafts <NUM> to rotate at different rotational speeds in a manner known by those skilled in the art. For instance, the differential assembly <NUM> may be rotatable about a differential axis <NUM> and may transmit torque to the axle shafts <NUM> and wheels. The differential axis <NUM> may be coaxially disposed with the wheel axis <NUM> in one or more configurations. In at least one configuration, the differential assembly <NUM> may have a ring gear <NUM> that may have teeth that mate or mesh with the teeth of a gear portion <NUM> of a drive pinion <NUM> that may be associated with the transmission <NUM>. Accordingly, the differential assembly <NUM> may receive torque from the drive pinion <NUM> via the ring gear <NUM> and transmit torque to the axle shafts <NUM>.

The axle shafts <NUM> may transmit torque between the differential assembly <NUM> and the traction wheel assemblies. Two axle shafts <NUM> may be provided that may extend in opposite directions from the differential assembly <NUM>. Each axle shaft <NUM> may have a first end and a second end. The first end may be operatively connected to the differential assembly <NUM>. The second end may be disposed opposite the first end and may be operatively connected to a wheel. The axle shafts <NUM> or a portion thereof may extend along and may be rotatable about an axis, such as the differential axis <NUM>.

The transmission <NUM> may transmit torque between the torque source <NUM> and the differential assembly <NUM>. Torque transmission may be bidirectional. In at least one configuration such as is shown in <FIG> and <FIG>, the transmission <NUM> may include a first shaft <NUM>, a first set of gears <NUM>, and a first shift collar <NUM>. The transmission <NUM> may also include a second shaft <NUM>, a second set of gears <NUM>, and a second shift collar <NUM> as is best shown in <FIG> and <FIG>.

Referring primarily to <FIG> and <FIG>, the first shaft <NUM> is rotatable about a first axis <NUM>. As is shown in <FIG>, the first axis <NUM> may be substantially perpendicular to the differential axis <NUM>. The term "substantially perpendicular" is used herein to designate features such as axes that are the perpendicular or very close to perpendicular with respect to each other and includes features that are within ±<NUM>° of being perpendicular each other. For instance, the first shaft <NUM> may be rotatably supported by one or more bearings, such as a first bearing <NUM> and a second bearing <NUM>. The first bearing <NUM> and the second bearing <NUM> may have any suitable configuration. For example, the first bearing <NUM> and the second bearing <NUM> may be configured as roller bearing assemblies that may encircle the first shaft <NUM>. In at least one configuration, the first shaft <NUM> may be part of the drive pinion <NUM> or may be rotatable with the drive pinion <NUM>.

The first set of gears <NUM> may include a plurality of gears that are rotatable about the first axis <NUM>. In the configuration shown, the first set of gears <NUM> includes a first drive gear <NUM>, a second drive gear <NUM>, and a third drive gear <NUM>; however, it is to be understood that a greater or lesser number of gears may be provided. A member of the first set of gears <NUM> may be rotatable about the first axis <NUM> with the first shaft <NUM> when that gear is coupled to the first shaft <NUM>. Conversely, the first shaft <NUM> may be rotatable about the first axis <NUM> with respect to a member of the first set of gears <NUM> that is decoupled from or not coupled to the first shaft <NUM>. A member of the first set of gears <NUM> may be selectively coupled to the first shaft <NUM> with the first shift collar <NUM> as will be discussed in more detail below.

The first drive gear <NUM> may receive the first shaft <NUM>. For example, the first drive gear <NUM> may have a through hole through which the first shaft <NUM> may extend. The first drive gear <NUM> may extend around the first axis <NUM> and the first shaft <NUM> and may have a plurality of teeth that may be arranged around and may face away from the first axis <NUM>. The teeth of the first drive gear <NUM> may contact and may mate or mesh with teeth of a first gear of the second set of gears <NUM> as will be discussed in more detail below. In at least one configuration, the first drive gear <NUM> may be fixedly coupled to the first shaft <NUM> such that the first drive gear <NUM> is rotatable about the first axis <NUM> with the first shaft <NUM> and such that the first drive gear <NUM> does not rotate about the first axis <NUM> with respect to the first shaft <NUM>. In at least one configuration, the first drive gear <NUM> may be axially positioned along the first axis <NUM> between the gear portion <NUM> and the second drive gear <NUM>. For instance, the first drive gear <NUM> may be axially positioned between the first bearing <NUM> and a spacer <NUM>.

The second drive gear <NUM> may receive the first shaft <NUM>. For example, the second drive gear <NUM> may have a through hole through which the first shaft <NUM> may extend. The second drive gear <NUM> may extend around the first axis <NUM> and the first shaft <NUM> and may have a plurality of teeth that may be arranged around and may face away from the first axis <NUM>. The teeth of the second drive gear <NUM> may contact and may mate or mesh with teeth of a second gear of the second set of gears <NUM> as will be discussed in more detail below. In at least one configuration, the second drive gear <NUM> may be fixedly coupled to the first shaft <NUM> such that the second drive gear <NUM> is rotatable about the first axis <NUM> with the first shaft <NUM> and such that the second drive gear <NUM> does not rotate about the first axis <NUM> with respect to the first shaft <NUM>. In at least one configuration, the second drive gear <NUM> may be axially positioned along the first axis <NUM> between the first drive gear <NUM> and the third drive gear <NUM>. In addition, the second drive gear <NUM> may be axially positioned closer to the third drive gear <NUM> than to the first drive gear <NUM>. For instance, the spacer <NUM> may be positioned between the first drive gear <NUM> and the second drive gear <NUM> to separate or increase the axial distance between the first drive gear <NUM> and the second drive gear <NUM> to provide alignment with a corresponding member of the second set of gears <NUM>, which may be arranged to accommodate the second shift collar <NUM> as will be discussed in more detail below. In addition, the second drive gear <NUM> may have a different diameter than the first drive gear <NUM>. For example, the second drive gear <NUM> may have a larger diameter than the first drive gear <NUM>.

The third drive gear <NUM> may receive the first shaft <NUM>. For example, the third drive gear <NUM> may have a through hole through which the first shaft <NUM> may extend. The third drive gear <NUM> may extend around the first axis <NUM> and the first shaft <NUM> and may have a plurality of teeth that may be arranged around and may face away from the first axis <NUM>. The teeth of the third drive gear <NUM> may contact and may mate or mesh with teeth of a third gear of the second set of gears <NUM> as will be discussed in more detail below. The third drive gear <NUM> may be rotatably disposed on the first shaft <NUM>. A bearing or bushing <NUM> may be received in the hole of the third drive gear <NUM> to rotatably support the third drive gear <NUM> on the first shaft <NUM>. The bushing <NUM> may also have a flange that may extend away from the first axis <NUM> and that may help separate the third drive gear <NUM> from the second drive gear <NUM>.

As is best shown in <FIG>, the third drive gear <NUM> may include clutch engagement teeth <NUM> that may be engaged by the first shift collar <NUM> to selectively couple the third drive gear <NUM> to the first shaft <NUM> as will be discussed in more detail below. The clutch engagement teeth <NUM> may have any suitable configuration. In the configuration shown, the clutch engagement teeth <NUM> are configured as a spline gear or spline teeth in which teeth may be arranged around the first axis <NUM> and may face away from and extend radially away from the first axis <NUM>. Alternatively or in addition, the clutch engagement teeth <NUM> may be configured as a face gear in which teeth may the arranged around the first axis <NUM> and may extend axially from a side of the third drive gear <NUM> toward the first shift collar <NUM>. The third drive gear <NUM> may be axially positioned along the first axis <NUM> between the second drive gear <NUM> and the first shift collar <NUM>. In addition, the third drive gear <NUM> may have a different diameter than the first drive gear <NUM> and the second drive gear <NUM>. For example, the third drive gear <NUM> may have a larger diameter than the second drive gear <NUM>.

The first shift collar <NUM> may be axially positioned between the third drive gear <NUM> and the second bearing <NUM>. The first shift collar <NUM> may receive the first shaft <NUM> and is rotatable about the first axis <NUM> with the first shaft <NUM>. In addition, the first shift collar <NUM> is moveable along the first axis <NUM> with respect to the first shaft <NUM> to selectively couple or selectively connect a member of the first set of gears <NUM> to the first shaft <NUM>. For instance, the first shift collar <NUM> may selectively couple the third drive gear <NUM> to the first shaft <NUM> as is shown in phantom in <FIG> and as will be discussed in more detail below. In at least one configuration and as is best shown in <FIG>, the first shift collar <NUM> may include a first shift collar hole <NUM> and a first shift collar spline <NUM>.

The first shift collar hole <NUM> may extend along the first axis <NUM>. The first shift collar hole <NUM> may be a through hole through which the first shaft <NUM> may extend.

The first shift collar spline <NUM> may operatively connect the first shift collar <NUM> to the first shaft <NUM>. The first shift collar spline <NUM> may be disposed in the first shift collar hole <NUM> and may include spline teeth that may extend toward the first axis <NUM>. The spline teeth may mesh or mate with corresponding spline teeth on the first shaft <NUM> or that are disposed on an intervening component that may be fixedly mounted to the first shaft <NUM>, such as a first annular ring <NUM>, which is best shown in <FIG>. For instance, the first annular ring <NUM> may have spline teeth <NUM> that may extend away from the first axis <NUM> and that may mesh with the teeth of the first shift collar spline <NUM>. The first annular ring <NUM> may at least partially encircle the first shaft <NUM> and may extend axially between the second bearing <NUM> and the third drive gear <NUM> and/or its bushing <NUM>.

The first shift collar spline <NUM> may selectively engage the third drive gear <NUM> to permit or inhibit rotation of the third drive gear <NUM> with respect to the first shaft <NUM>. The third drive gear <NUM> may be rotatable about the first axis <NUM> with respect to the first shaft <NUM> when the first shift collar <NUM> is disengaged from the third drive gear <NUM>. For instance, the third drive gear <NUM> may be rotatable with respect to the first shaft <NUM> when the first shift collar spline <NUM> does not mate or mesh with the clutch engagement teeth <NUM> of the third drive gear <NUM> and thus the first shift collar <NUM> does not connect the third drive gear <NUM> to the first shaft <NUM>. The third drive gear <NUM> may be rotatable about the first axis <NUM> with the first shaft <NUM> when the first shift collar <NUM> connects the third drive gear <NUM> to the first shaft <NUM>, such as when the first shift collar spline <NUM> mates or meshes with the clutch engagement teeth <NUM> of the third drive gear <NUM>. It is also contemplated that the first shift collar <NUM> may be provided with a face gear that may mate or mesh with clutch engagement teeth <NUM> of the third drive gear <NUM> that may also be configured as a face gear. In such a configuration, the first shift collar spline <NUM> may not mate or mesh with the clutch engagement teeth <NUM>.

Referring primarily to <FIG> and <FIG>, the second shaft <NUM> may be spaced apart from the first shaft <NUM> and is rotatable about a second axis <NUM>. The second axis <NUM> may be disposed substantially parallel to the first axis <NUM>. The term "substantially parallel" is used herein to designate features such as axes that are the parallel or very close to parallel with respect to each other and includes features that are within ±<NUM>° of being parallel each other. The second shaft <NUM> may be rotatably supported by one or more bearings, such as a first bearing <NUM> and a second bearing <NUM>. The first bearing <NUM> and the second bearing <NUM> may have any suitable configuration. For instance, the first bearing <NUM> and the second bearing <NUM> may be configured as roller bearing assemblies that may encircle the second shaft <NUM>. The second shaft <NUM> may be operatively connected to the torque source <NUM>. For example, torque may be transmitted from the torque source <NUM> to the second shaft <NUM>, and then torque may be transmitted from the second shaft <NUM> to the first shaft <NUM> via gears. In a configuration having an electrical power source, the second shaft <NUM> may be operatively connected to the rotor <NUM>, such as by directly connecting a rotor shaft to the second shaft <NUM> or by using a connecting gear set <NUM>, an example of which is best shown in <FIG>. For instance, the connecting gear set <NUM> may have a first connecting gear that is rotatable with the rotor <NUM> and that meshes with a second connecting gear that is rotatable with the second shaft <NUM>. In at least one configuration, the transmission <NUM> may be positioned on an opposite side of the differential assembly <NUM> from the torque source <NUM>.

Referring again to <FIG> and <FIG>, the second set of gears <NUM> may include a plurality of gears that are rotatable about the second axis <NUM>. Each member of the second set of gears <NUM> meshes with a different member of the first set of gears <NUM>. In the configuration shown, the second set of gears <NUM> includes first gear <NUM>, a second gear <NUM>, and a third gear <NUM>; however, it is to be understood that a greater or lesser number of gears may be provided. A member of the second set of gears <NUM> may be rotatable about the second axis <NUM> with the second shaft <NUM> when that gear is coupled to the second shaft <NUM>. Conversely, the second shaft <NUM> may be rotatable about the second axis <NUM> with respect to a member of the second set of gears <NUM> that is decoupled from or not coupled to the second shaft <NUM>. A member of the second set of gears <NUM> may be selectively coupled to the second shaft <NUM> with the second shift collar <NUM> as will be discussed in more detail below.

The first gear <NUM> may receive the second shaft <NUM>. For example, the first gear <NUM> may have a through hole through which the second shaft <NUM> may extend. The first gear <NUM> may extend around the second axis <NUM> and the second shaft <NUM> and may have a plurality of teeth that may be arranged around and may face away from the second axis <NUM>. The teeth of the first gear <NUM> may contact and may mate or mesh with teeth of the first drive gear <NUM> of the first set of gears <NUM>. In at least one configuration, the first gear <NUM> may be rotatably disposed on the second shaft <NUM>. A bearing or bushing <NUM> may be received in the hole of the first gear <NUM> and may rotatably support the first gear <NUM> on the second shaft <NUM>.

As is best shown in <FIG>, the first gear <NUM> may include clutch engagement teeth <NUM> that may be engaged by the second shift collar <NUM> to selectively couple the first gear <NUM> to the second shaft <NUM> as will be discussed in more detail below. The clutch engagement teeth <NUM> may have any suitable configuration. In the configuration shown, the clutch engagement teeth <NUM> are configured as a spline gear or spline teeth in which teeth may be arranged around the second axis <NUM> and may face away from and extend radially away from the second axis <NUM>. Alternatively or in addition, the clutch engagement teeth <NUM> may be configured as a face gear in which teeth may the arranged around the second axis <NUM> and may extend axially from a side of the first gear <NUM> toward the second shift collar <NUM>. The first gear <NUM> may be axially positioned along the second axis <NUM> between the first bearing <NUM> and the second gear <NUM>.

The second gear <NUM> may receive the second shaft <NUM>. For example, the second gear <NUM> may have a through hole through which the second shaft <NUM> may extend. The second gear <NUM> may extend around the second axis <NUM> and the second shaft <NUM> and may have a plurality of teeth that may be arranged around and may face away from the second axis <NUM>. The teeth of the second gear <NUM> may contact and may mate or mesh with teeth of a second drive gear <NUM> of the first set of gears <NUM>. In at least one configuration, the second gear <NUM> may be rotatably disposed on the second shaft <NUM>. A bearing or bushing <NUM> may be received in the hole of the second gear <NUM> and may rotatably support the second gear <NUM> on the second shaft <NUM>.

In at least one configuration, the second gear <NUM> may include second clutch engagement teeth <NUM> that may be engaged by the second shift collar <NUM> to selectively couple the second gear <NUM> to the second shaft <NUM> as will be discussed in more detail below. The second clutch engagement teeth <NUM> may have any suitable configuration. In the configuration shown, the second clutch engagement teeth <NUM> are configured as a spline gear or spline teeth in which teeth may be arranged around the second axis <NUM> and may face away from and extend radially away from the second axis <NUM>. Alternatively or in addition, the second clutch engagement teeth <NUM> may be configured as a face gear in which teeth may the arranged around the second axis <NUM> and may extend axially from a side of the second gear <NUM> toward the second shift collar <NUM>. The second gear <NUM> may be axially positioned along the second axis <NUM> between the first gear <NUM> and the third gear <NUM>. For example, the second gear <NUM> may be axially positioned between the second shift collar <NUM> and the third gear <NUM>. In addition, the second gear <NUM> may be axially positioned closer to the third gear <NUM> than to the first gear <NUM>. For instance, a spacer <NUM> may be positioned between the first gear <NUM> and the second gear <NUM> to separate or increase the axial distance between the first gear <NUM> and the second gear <NUM> to provide sufficient room for moving the second shift collar <NUM> as will be discussed in more detail below. The spacer <NUM> may be integrally formed with the second shaft <NUM> or may be provided as a separate component that may extend from the second shaft <NUM>. In addition, the second gear <NUM> may have a different diameter than the first gear <NUM>. For example, the second gear <NUM> may have a smaller diameter than the first gear <NUM>.

The third gear <NUM> may receive the second shaft <NUM>. For example, the third gear <NUM> may have a through hole through which the second shaft <NUM> may extend. The third gear <NUM> may extend around the second axis <NUM> and the second shaft <NUM> and may have a plurality of teeth that may be arranged around and may face away from the second axis <NUM>. The teeth of the third gear <NUM> may contact and may mate or mesh with teeth of the third drive gear <NUM> of the first set of gears <NUM> as will be discussed in more detail below. In at least one configuration, the third gear <NUM> may be fixedly coupled to the second shaft <NUM> such that the third gear <NUM> is rotatable about the second axis <NUM> with the second shaft <NUM> and such that the third gear <NUM> does not rotate about the second axis <NUM> with respect to the second shaft <NUM>. In at least one configuration, the third gear <NUM> may be axially positioned along the second axis <NUM> between the second bearing <NUM> and the second drive gear <NUM>. In addition, the third gear <NUM> may have a different diameter than the first gear <NUM> and the second gear <NUM>. For instance, the third gear <NUM> may have a smaller diameter than the second gear <NUM>.

The second shift collar <NUM> may be axially positioned between the first gear <NUM> and the second gear <NUM>. The second shift collar <NUM> may receive the second shaft <NUM> and is rotatable about the second axis <NUM> with the second shaft <NUM>. In addition, the second shift collar <NUM> is moveable along the second axis <NUM> with respect to the second shaft <NUM> to selectively couple or selectively connect a member of the second set of gears <NUM> to the second shaft <NUM>. For instance, the second shift collar <NUM> may selectively couple the first gear <NUM> or the second gear <NUM> to the second shaft <NUM> as will be discussed in more detail below. The second shift collar <NUM> may also decouple the first gear <NUM> and the second gear <NUM> from the second shaft <NUM> in an intermediate portion that is shown in phantom on <FIG>. In at least one configuration and as is best shown in <FIG>, the second shift collar <NUM> may include a second shift collar hole <NUM> and a second shift collar spline <NUM>.

The second shift collar hole <NUM> may extend along the second axis <NUM>. The second shift collar hole <NUM> may be a through hole through which the second shaft <NUM> may extend.

The second shift collar spline <NUM> may operatively connect the second shift collar <NUM> to the second shaft <NUM>. The second shift collar spline <NUM> may be disposed in the second shift collar hole <NUM> and may include spline teeth that may extend toward the second axis <NUM>. The spline teeth may mesh or mate with corresponding spline teeth on the second shaft <NUM> or and intervening component that may be fixedly mounted to the second shaft <NUM>.

The second shift collar spline <NUM> may selectively engage the first gear <NUM> or the second gear <NUM> to permit or inhibit rotation of the first gear <NUM> or the second gear <NUM> with respect to the second shaft <NUM>. For instance, the second shift collar spline <NUM> may mate or mesh with the clutch engagement teeth <NUM> of the first gear <NUM> to rotatably couple the first gear <NUM> to the second shaft <NUM> as shown in solid lines at position A in <FIG>. The first gear <NUM> may be rotatable about the second axis <NUM> with respect to the second shaft <NUM> when the second shift collar <NUM> is disengaged from the first gear <NUM> or does not connect the first gear <NUM> to the second shaft <NUM>. For instance, the first gear <NUM> may be rotatable about the second axis <NUM> with respect to the second shaft <NUM> when the second shift collar spline <NUM> does not mate or mesh with the clutch engagement teeth <NUM> of the first gear <NUM>.

The second shift collar spline <NUM> may not mate or mesh with the clutch engagement teeth <NUM> of the first gear <NUM> and the second clutch engagement teeth <NUM> of the second gear <NUM> when in the intermediate position shown with phantom lines at position B, thereby permitting the second shaft <NUM> to rotate with respect to the first gear <NUM> and the second gear <NUM>.

The second shift collar spline <NUM> may mate or mesh with the second clutch engagement teeth <NUM> of the second gear <NUM> to rotatably couple the second gear <NUM> to the second shaft <NUM> when the second shift collar <NUM> is moved to the right from the perspective shown in <FIG> to position C. The second gear <NUM> may be rotatable about the second axis <NUM> with respect to the second shaft <NUM> when the second shift collar <NUM> is disengaged from the second gear <NUM> or does not connect the second gear <NUM> to the second shaft <NUM>. For instance, the second gear <NUM> may be rotatable about the second axis <NUM> with respect to the second shaft <NUM> when the second shift collar spline <NUM> does not mate or mesh with the second clutch engagement teeth <NUM> of the second gear <NUM>.

It is also contemplated that the second shift collar <NUM> may be provided with a face gear that may mate or mesh with clutch engagement teeth <NUM> of the first gear <NUM> that may also be configured as a face gear, may be provided with a face gear that may mate or mesh with the second clutch engagement teeth <NUM> of the second gear <NUM> that may be configured as a face gear, or combinations thereof.

Referring primarily to <FIG> and <FIG>, the shift mechanism <NUM> may control positioning of a shift collar, such as the first shift collar <NUM> and the second shift collar <NUM>. In at least one configuration, the shift mechanism <NUM> may include a shift rail <NUM>, a first shift fork <NUM>, a second shift fork <NUM>, a barrel cam <NUM>, or combinations thereof.

The shift rail <NUM> extends along a shift rail axis <NUM>. The shift rail axis <NUM> may be disposed substantially parallel to the first axis <NUM>, the second axis <NUM>, or both. The shift rail <NUM> may be fixedly positioned such that the shift rail <NUM> may not move along or rotate about the shift rail axis <NUM>. The shift rail <NUM> is spaced apart from the barrel cam <NUM> and may support the first shift fork <NUM> and the second shift fork <NUM>.

Referring to <FIG> and <FIG>, the first shift fork <NUM> operatively connects the first shift collar <NUM> to the barrel cam <NUM>. The first shift fork <NUM> is slidable along the shift rail axis <NUM> with respect to the shift rail <NUM>. In at least one configuration, the first shift fork <NUM> may include a tubular portion <NUM>, a fork arm <NUM>, and a guide feature <NUM>.

The tubular portion <NUM> may receive the shift rail <NUM>. In at least one configuration, the tubular portion <NUM> may have a first end <NUM>, a second end <NUM>, and a shift fork hole <NUM>.

The first end <NUM> may face toward the second shift fork <NUM>.

The second end <NUM> may be disposed opposite the first end <NUM>. As such, the second end <NUM> may face away from the second shift fork <NUM>.

The shift fork hole <NUM> may extend from the first end <NUM> to the second end <NUM>. The shift rail <NUM> may extend through the shift fork hole <NUM>.

The fork arm <NUM> may extend from the tubular portion <NUM> to the first shift collar <NUM>. The fork arm <NUM> may have any suitable configuration. For instance, the fork arm <NUM> may have a pair of prongs that may be received in a groove of the first shift collar <NUM> and that may allow the first shift collar <NUM> to rotate about the first axis <NUM> with respect to the prongs. The fork arm <NUM> may be disposed proximate the second end <NUM> of the tubular portion <NUM>.

The guide feature <NUM> may operatively connect the first shift fork <NUM> to the barrel cam <NUM>. The guide feature <NUM> may extend from the tubular portion <NUM> in a direction that extends away from the shift fork hole <NUM> and the shift rail axis <NUM>. In at least one configuration, the guide feature <NUM> may extend along a guide feature axis <NUM> that may be disposed substantially perpendicular to the shift rail axis <NUM>, a barrel cam axis of the barrel cam <NUM>, or both. The guide feature <NUM> may be disposed proximate the first end <NUM> of the tubular portion <NUM>.

Referring to <FIG> and <FIG>, the second shift fork <NUM> may be spaced apart from the first shift fork <NUM>. The second shift fork <NUM> operatively connects the second shift collar <NUM> to the barrel cam <NUM>. The second shift fork <NUM> may have a similar configuration as the first shift fork <NUM>. The second shift fork <NUM> is slidable along the shift rail axis <NUM> with respect to the shift rail <NUM>. In at least one configuration, the second shift fork <NUM> may include a tubular portion <NUM>', a fork arm <NUM>', and a guide feature <NUM>'.

The tubular portion <NUM>' may receive the shift rail <NUM>. In at least one configuration, the tubular portion <NUM>' may have a first end <NUM>', a second end <NUM>', and a shift fork hole <NUM>'.

The first end <NUM>' may face away from the first shift fork <NUM>.

The second end <NUM>' may be disposed opposite the first end <NUM>'. As such, the second end <NUM>' may face toward the first shift fork <NUM>.

The shift fork hole <NUM>' may extend from the first end <NUM>' to the second end <NUM>'. The shift rail <NUM> may extend through the shift fork hole <NUM>'.

The fork arm <NUM>' may extend from the tubular portion <NUM>' of the second shift fork <NUM> to the second shift collar <NUM>. The fork arm <NUM>' may have any suitable configuration. For instance, the fork arm <NUM>' may have a pair of prongs that may be received in a groove of the second shift collar <NUM> and that may allow the second shift collar <NUM> to rotate about the second axis <NUM> with respect to the prongs. The fork arm <NUM>' may be disposed proximate the second end <NUM>' of the tubular portion <NUM>.

The guide feature <NUM>' may operatively connect the second shift fork <NUM> to the barrel cam <NUM>. The guide feature <NUM>' may extend from the tubular portion <NUM>' in a direction that extends away from the shift fork hole <NUM>' and the shift rail axis <NUM>. In at least one configuration, the guide feature <NUM>' may extend along a guide feature axis <NUM>' that may be disposed substantially perpendicular to the shift rail axis <NUM>, a barrel cam axis of the barrel cam <NUM>, or both. The guide feature <NUM>' may be disposed proximate the first end <NUM>' of the tubular portion <NUM>'.

Referring primarily to <FIG> and <FIG>, the barrel cam <NUM> may be operatively connected to the first shift collar <NUM>, the second shift collar <NUM>, or both. The barrel cam <NUM> may be spaced apart from the transmission <NUM> and is spaced apart from the shift rail <NUM>. In at least one configuration, the barrel cam <NUM> may have a generally cylindrical configuration.

The barrel cam <NUM> is rotatable about a barrel cam axis <NUM>. For instance, the barrel cam <NUM> may be rotatably supported by a first barrel cam bearing <NUM> and the second barrel cam bearing <NUM>. The first barrel cam bearing <NUM> and the second barrel cam bearing <NUM> may have any suitable configuration. For example, the first barrel cam bearing <NUM> and the second barrel cam bearing <NUM> may be configured as roller bearing assemblies that may extend around and may encircle the barrel cam <NUM>. The first barrel cam bearing <NUM> and the second barrel cam bearing <NUM> may be disposed proximate opposite ends of the barrel cam <NUM>.

The barrel cam axis <NUM> is disposed substantially parallel to the first axis <NUM>, the second axis <NUM>, the shift rail axis <NUM>, or combinations thereof. Rotation of the barrel cam <NUM> about the barrel cam axis <NUM> controls movement of the first shift collar <NUM> along the first axis <NUM> and controls movement of the second shift collar <NUM> along the second axis <NUM>. The shift rail axis <NUM> is disposed closer to the first axis <NUM> than the barrel cam axis <NUM> is disposed to the first axis <NUM>. The shift rail axis <NUM> is disposed closer to the second axis <NUM> than the barrel cam axis <NUM> is disposed to the second axis <NUM>. In at least one configuration and as is best shown in <FIG>, the barrel cam <NUM> may have an exterior side <NUM> and a coupling feature <NUM>. The barrel cam <NUM> may define one or more grooves, such as a first groove <NUM> and a second groove <NUM>.

The exterior side <NUM> may face away from the barrel cam axis <NUM>. The exterior side <NUM> or a portion thereof may be cylindrical. A plurality of detent features <NUM> may be provided with the exterior side <NUM>. The detent features <NUM> may be spaced apart from each other and may be positioned to correspond with rotational positions of the barrel cam <NUM>, such as the positions shown in <FIG>. The detent features <NUM> may have any suitable configuration. For instance, a detent feature <NUM> may be configured as an indentation that may extend toward the barrel cam axis <NUM>. A detent feature <NUM> may be engaged by a detent mechanism <NUM>, which is best shown in <FIG>. The detent feature <NUM> may help hold the barrel cam <NUM> in a desired rotational position. The detent mechanism <NUM> may slide along the exterior side <NUM> when the barrel cam <NUM> is rotated about the barrel cam axis <NUM> between different rotational positions and their associated detent features <NUM>.

The coupling feature <NUM> may facilitate coupling of the barrel cam <NUM> to an actuator that may rotate the barrel cam <NUM> about the barrel cam axis <NUM>. In at least one configuration, the coupling feature <NUM> may extend from an end of the barrel cam <NUM> and may be disposed along the barrel cam axis <NUM>. The coupling feature <NUM> may have any suitable configuration. For instance the coupling feature <NUM> may have a male configuration, a female configuration, or combinations thereof. The actuator may have any suitable configuration. For instance, the actuator may be an electrical actuator, mechanical actuator, electromechanical actuator, or the like.

Referring to <FIG> and <FIG>, the first groove <NUM> may guide movement of the first shift fork <NUM> and thus guide movement of the first shift collar <NUM>. For instance, the first groove <NUM> may extend from the exterior side <NUM> toward the barrel cam axis <NUM> and may receive the guide feature <NUM> of the first shift fork <NUM>. The guide feature <NUM> may extend past the exterior side <NUM> and into the first groove <NUM>. The first groove <NUM> may be axially positioned between the first barrel cam bearing <NUM> and the second barrel cam bearing <NUM>. For instance, the first groove <NUM> may be axially positioned between the second barrel cam bearing <NUM> and the second groove <NUM>.

The first groove <NUM> may extend completely around or continuously around the barrel cam axis <NUM>. As such the first groove <NUM> may be a continuous ring or loop that does not have an end. The first groove <NUM> may have a noncircular configuration that may jog along the barrel cam axis <NUM> such that the first groove <NUM> may become closer to the second groove <NUM> or may move further away from the second groove <NUM> as the first groove <NUM> extends around the barrel cam axis <NUM>. In at least one configuration, the first groove <NUM> may have a first groove side <NUM> and a second groove side <NUM>, which are best shown with reference to <FIG> and <FIG>.

The first groove side <NUM> and the second groove side <NUM> may extend from the exterior side <NUM> toward the barrel cam axis <NUM>. The first groove side <NUM> and the second groove side <NUM> may extend continuously around the barrel cam axis <NUM> and may be spaced apart from each other. For instance, the first groove side <NUM> and the second groove side <NUM> may be mirror images of each other and may be equidistantly spaced from each other. The first groove side <NUM> and the second groove side <NUM> may be disposed substantially parallel to each other in one or more embodiments. The first groove side <NUM> and the second groove side <NUM> may cooperate to constrain and control axial movement of the first shift fork <NUM>. For example, the guide feature <NUM> of the first shift fork <NUM> may engage the first groove side <NUM> to inhibit movement of the first shift fork <NUM> toward the first barrel cam bearing <NUM> while the guide feature <NUM> may engage the second groove side <NUM> to inhibit movement of the first shift fork <NUM> toward the second barrel cam bearing <NUM>.

Referring to <FIG> and <FIG>, the second groove <NUM> may guide movement of the second shift fork <NUM> and thus guide movement of the second shift collar <NUM>. For instance, the second groove <NUM> may extend from the exterior side <NUM> toward the barrel cam axis <NUM> and may receive the guide feature <NUM>' of the second shift fork <NUM>. The guide feature <NUM>' may extend past the exterior side <NUM> and into the second groove <NUM>. The second groove <NUM> may be axially positioned between the first barrel cam bearing <NUM> and the second barrel cam bearing <NUM>. For example, the second groove <NUM> may be axially positioned between the first barrel cam bearing <NUM> and the first groove <NUM>.

The second groove <NUM> may extend completely around or continuously around the barrel cam axis <NUM>. As such the second groove <NUM> may be a continuous ring or loop that does not have an end. The second groove <NUM> may have a noncircular configuration that may jog along the barrel cam axis <NUM> such that the second groove <NUM> may become closer to the first groove <NUM> or may move further away from the first groove <NUM> as the second groove <NUM> extends around the barrel cam axis <NUM>. However, the second groove <NUM> may jog differently than the first groove <NUM>. For instance, a portion of the first groove <NUM> may jog away from the second groove <NUM> at one or more rotational positions. For example, the first groove <NUM> may jog away from the second groove <NUM> at one or more rotational positions at which the second groove <NUM> does not jog toward the first groove <NUM>.

In at least one configuration, the second groove <NUM> may have a first groove side <NUM>' and a second groove side <NUM>', which are best shown with reference to <FIG> and <FIG>.

The first groove side <NUM>' and the second groove side <NUM>' may extend from the exterior side <NUM> toward the barrel cam axis <NUM>. The first groove side <NUM>' and the second groove side <NUM>' may extend continuously around the barrel cam axis <NUM> and may be spaced apart from each other. For instance, the first groove side <NUM>' and the second groove side <NUM>' may be mirror images of each other and may be equidistantly spaced from each other. The first groove side <NUM>' and the second groove side <NUM>' may be disposed substantially parallel to each other in one or more embodiments. The first groove side <NUM>' and the second groove side <NUM>' may cooperate to constrain and control axial movement of the second shift fork <NUM>. For example, the guide feature <NUM>' of the second shift fork <NUM> may engage the first groove side <NUM>' to inhibit movement of the second shift fork <NUM> toward the first barrel cam bearing <NUM> while the guide feature <NUM>' may engage the second groove side <NUM>' to inhibit movement of the second shift fork <NUM> toward the second barrel cam bearing <NUM>.

Referring to <FIG>, examples that illustrate operation of the shift mechanism <NUM> and movement of the first shift collar <NUM> and the second shift collar <NUM> will now be described. Rotation of the barrel cam <NUM> and shifting of a shift collar may occur in response to an operator command, may be automated, or combinations thereof. In at least one configuration, a shift may be executed when the rotational speed of a shift collar and the gear that is being engaged or disengaged are sufficiently synchronized. Sufficient synchronization to permit shifting or movement of a collar may be attained using a synchronizer, by controlling the rotational speed of the first shaft <NUM>, by controlling the rotational speed of the second shaft <NUM>, or combinations thereof.

In <FIG> examples of shift collar positions are shown. Examples of configurations of the first groove <NUM> and the second groove <NUM> that may be associated with these positions is represented schematically in <FIG>; however, it is to be understood that the shift collar positions may be rearranged or additional shift collar positions may be added, in which case the manner in which the first groove <NUM> and the second groove <NUM> jog with respect to each other may differ from the example shown. In <FIG>, the first groove <NUM> and that second groove <NUM> are projected into a planar representation with connector A representing that the first groove <NUM> is connected and continuous and connector B representing that the second groove <NUM> is connected and continuous.

Referring to <FIG>, the barrel cam <NUM> is shown in a low-speed position. The first shift collar <NUM> may couple the third drive gear <NUM> to the first shaft <NUM> such that the third drive gear <NUM> is rotatable with the first shaft <NUM>. The second shift collar <NUM> may not couple the first gear <NUM> or the second gear <NUM> to the second shaft <NUM>. As such, torque may be transmitted between the first shaft <NUM> and the second shaft <NUM> via the third drive gear <NUM> and the third gear <NUM>.

Referring to <FIG>, the barrel cam <NUM> is shown in a mid-speed position. The first shift collar <NUM> may not couple the third drive gear <NUM> to the first shaft <NUM> and is moved to the right from the position shown in <FIG>. The second shift collar <NUM> is moved to the right from the position shown in <FIG> and may couple the second gear <NUM> to the second shaft <NUM> but may not couple the first gear <NUM> to the second shaft <NUM>. As such, torque may be transmitted between the first shaft <NUM> and the second shaft <NUM> via the second drive gear <NUM> and the second gear <NUM>.

Referring to <FIG>, the barrel cam <NUM> is shown in a high-speed position. The first shift collar <NUM> is in the same position as in <FIG> and may not couple the third drive gear <NUM> to the first shaft <NUM>. The second shift collar <NUM> is moved to the left from the position shown in <FIG> to couple the first gear <NUM> to the second shaft <NUM> but does not couple the second gear <NUM> to the second shaft <NUM>. As such, torque may be transmitted between the first shaft <NUM> and the second shaft <NUM> via the first drive gear <NUM> and the first gear <NUM>.

Referring to <FIG>, the barrel cam <NUM> is shown in a neutral position. The first shift collar <NUM> is in the same position as in <FIG> may not couple the third drive gear <NUM> to the first shaft <NUM>. The second shift collar <NUM> is in the same position as <FIG> and may not couple the first gear <NUM> or the second gear <NUM> to the second shaft <NUM>. As such, torque may not be transmitted between the first shaft <NUM> and the second shaft <NUM>.

Claim 1:
An axle assembly (<NUM>) comprising:
a first shaft (<NUM>) that is rotatable about a first axis (<NUM>);
a second shaft (<NUM>) that is rotatable about a second axis (<NUM>);
a first set of gears (<NUM>) that is rotatable about the first axis (<NUM>); and
a second set of gears (<NUM>) that is rotatable about the second axis (<NUM>), wherein each member of the second set of gears (<NUM>) meshes with a different member of the first set of gears (<NUM>);
a first shift collar (<NUM>) that is rotatable about the first axis (<NUM>) with the first shaft (<NUM>) and moveable along the first axis (<NUM>) with respect to the first shaft (<NUM>) to selectively connect a member of the first set of gears (<NUM>) to the first shaft (<NUM>); and
a second shift collar (<NUM>) that is rotatable about the second axis (<NUM>) with the second shaft (<NUM>) and moveable along the second axis (<NUM>) with respect to the second shaft (<NUM>) to selectively connect a member of the second set of gears (<NUM>) to the second shaft (<NUM>);
a shift rail (<NUM>) that extends along a shift rail axis (<NUM>);
a barrel cam (<NUM>) that is rotatable about a barrel cam axis (<NUM>) that is disposed substantially parallel to the first axis (<NUM>) and operatively connected to the first shift collar (<NUM>) and the second shift collar (<NUM>), wherein rotation of the barrel cam (<NUM>) about the barrel cam axis (<NUM>) controls movement of the first shift collar (<NUM>) along the first axis (<NUM>) and controls movement of the second shift collar (<NUM>) along the second axis (<NUM>), wherein a first shift fork (<NUM>) operatively connects the first shift collar (<NUM>) to the barrel cam (<NUM>), a second shift fork (<NUM>) operatively connects the second shift collar (<NUM>) to the barrel cam (<NUM>), the first shift fork (<NUM>) and the second shift fork (<NUM>) are slidable along the shift rail axis (<NUM>) with respect to the shift rail (<NUM>), which is spaced apart from the barrel cam (<NUM>) and extends substantially parallel to the barrel cam axis (<NUM>), and the shift rail axis (<NUM>) is disposed closer to the first axis (<NUM>) and the second axis (<NUM>) than the barrel cam axis (<NUM>) is disposed to the first axis (<NUM>) and the second axis (<NUM>).