Patent Description:
An axle assembly having a clutch collar is disclosed in <CIT>.

<CIT> discloses, in the opinon of the Examining Division of the European Patent Office, a shift mechanism comprising: an actuator that has an actuator shaft that is rotatable about an actuator axis; a detent linkage that is rotatable about the actuator axis with the actuator shaft; a linkage that is rotatable about the actuator axis; a shift collar that is operatively connected to the linkage and moveable along an axis; and a biasing member that operatively connects the detent linkage to the linkage and that permits the actuator shaft and the detent linkage to rotate about the actuator axis with respect to the linkage when the shift collar is inhibited from moving along the axis, wherein the detent linkage has a detent linkage shaft that extends along the actuator axis.

According to the invention as defined in claim <NUM>, a shift mechanism is provided comprising:.

The biasing member may be positioned along the actuator axis between the linkage and the detent linkage.

The detent linkage has a detent linkage shaft that extends along the actuator axis. The biasing member encircles the detent linkage shaft.

A first bushing may extend around the detent linkage shaft. The biasing member may extend around the first bushing.

The detent linkage may have a linkage plate that is disposed at an end of the detent linkage shaft. A first bushing and the biasing member may extend axially between the detent linkage plate and the linkage.

The biasing member have a first coil that extends around the actuator axis. The biasing may have a second coil that extends around the actuator axis. The second coil may be attached to the first coil. The first coil may be disposed closer to the linkage than to the detent linkage.

The first coil may extend from the linkage to the second coil. The second coil may extend from the first coil to the linkage plate.

The biasing member may control relative rotational movement of the linkage and the detent linkage. The biasing member may include a first coil that extends around the actuator axis. The first coil may have a first tab that extends away from the actuator axis. The biasing member may further include a second coil that extends around the actuator axis. The second coil may be disposed adjacent to the first coil. The second coil may have a second tab that extends away from the actuator axis. The first tab and the second tab may be positioned about the actuator axis such that the first tab is rotationally offset from the second tab.

A first pin may extend from the detent linkage plate toward the linkage. The first pin may be engageable with the second tab.

A second pin may extend from the linkage. The second pin may be engageable with the first tab. The first pin and the second pin may be engageable with the first tab and the second tab.

The first tab and the second tab may engage the second pin when the shift collar is free to move along the axis.

Either the first tab or the second tab may engage the second pin when the detent linkage is rotated about the actuator axis and the shift collar may be inhibited from moving along the axis.

The first pin may engage the second tab but not the first tab. The second pin may engage the first tab but not the second tab when the detent linkage is rotated about the actuator axis in a first rotational direction and the shift collar is inhibited from moving in a first direction along the axis.

The actuator may be mounted to a housing that defines a hole through which the actuator shaft extends. The detent linkage shaft may extend into the hole in the housing. The detent linkage shaft may receive the actuator shaft. A second bushing may be received inside the hole in the housing. The second bushing may extend between the housing and the detent linkage shaft.

The housing may define a cavity that receives the shift collar. The second bushing may be axially positioned between a first washer that is disposed in the cavity and a second washer that is disposed outside of the cavity. The first washer may extend from the linkage to the second bushing. The second washer may extend from the second bushing to a fastener that is coupled to the detent linkage shaft to inhibit axial movement of the detent linkage along the actuator axis.

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

One or more axle assemblies may be provided with the vehicle. As is best shown with reference to <FIG> and <FIG>, the axle assembly <NUM> may include a housing assembly <NUM>, a differential assembly <NUM>, at least one axle shaft <NUM>, an electric motor module <NUM>, and a transmission module <NUM>, a drive pinion <NUM>, a shift mechanism <NUM>, or combinations thereof.

The axle housing <NUM> may receive and may support the axle shafts <NUM>. In at least one configuration, the axle housing <NUM> may include a center portion <NUM> and at least one arm portion <NUM>.

The center portion <NUM> may be disposed proximate the center of the axle housing <NUM>. As is best shown in <FIG>, the center portion <NUM> may define a cavity <NUM> that may at least partially receive the differential assembly <NUM>. A lower region of the center portion <NUM> may at least partially define a sump portion <NUM> that may contain or collect lubricant <NUM>. Lubricant <NUM> in the sump portion <NUM> may be splashed by a ring gear <NUM> of the differential assembly <NUM> and distributed to lubricate various components that may or may not be received in the housing assembly <NUM>. For instance, some splashed lubricant <NUM> may lubricate components that are received in the cavity <NUM> like the differential assembly <NUM>, bearing assemblies that rotatably support the differential assembly <NUM>, a drive pinion <NUM>, and so on, while some splashed lubricant <NUM> may be routed out of the cavity <NUM> to lubricate components located outside of the housing assembly <NUM>, such as components associated with the transmission module <NUM>, the shift mechanism <NUM>, or both.

Referring to <FIG>, one or more arm portions <NUM> may extend from the center portion <NUM>. For instance, two arm portions <NUM> may extend in opposite directions from the center portion <NUM> and away from the differential assembly <NUM>. The arm portions <NUM> may have similar configurations. For example, the arm portions <NUM> may each have a hollow tubular configuration that may extend around and may receive a corresponding axle shaft <NUM> and may help separate or isolate the axle shaft <NUM> or a portion thereof from the surrounding environment. An arm portion <NUM> or a portion thereof may or may not be integrally formed with the center portion <NUM>. It is also contemplated that the arm portions <NUM> may be omitted.

Referring primarily to <FIG>, the differential carrier <NUM> may be mounted to the center portion <NUM> of the axle housing <NUM>. The differential carrier <NUM> may support the differential assembly <NUM> and may facilitate mounting of the electric motor module <NUM>. For example, the differential carrier <NUM> may include one or more bearing supports that may support a bearing like a roller bearing assembly that may rotatably support the differential assembly <NUM>. In at least one configuration, the differential carrier <NUM> may include a mounting flange <NUM> and/or a bearing support wall <NUM>.

The mounting flange <NUM> may facilitate mounting of the electric motor module <NUM>. As an example, the mounting flange <NUM> may be configured as a ring that may extend around the axis <NUM>. In at least one configuration, the mounting flange <NUM> may include a set of fastener holes that may be configured to receive fasteners that may secure the electric motor module <NUM> to the mounting flange <NUM>.

The bearing support wall <NUM> may support bearings that may rotatably support other components of the axle assembly <NUM>. For example, the bearing support wall <NUM> may support a bearing that may rotatably support the drive pinion <NUM>, a bearing that may rotatably support a rotor of the electric motor module <NUM>, or both. The bearing support wall <NUM> may extend in an axial direction away from the axle housing <NUM> and may extend around the axis <NUM>. The bearing support wall <NUM> may define a hole that may extend along or around the axis <NUM> and receive the drive pinion <NUM> and the bearings that rotatably support the drive pinion <NUM>. The bearing support wall <NUM> may be integrally formed with the differential carrier <NUM> or may be a separate component that is fastened to the differential carrier <NUM>.

Referring to <FIG>, the differential assembly <NUM> may be at least partially received in the center portion <NUM> of the housing assembly <NUM>. 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 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. 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 of a drive pinion <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 drive pinion <NUM> may operatively connect the transmission module <NUM> to the differential assembly <NUM>. As such, the drive pinion <NUM> may transmit torque between the differential assembly <NUM> and the transmission module <NUM>. In at least one configuration, the drive pinion <NUM> may be rotatable about the axis <NUM> and may be rotatably supported inside another component, such as the bearing support wall <NUM>.

Referring primarily to <FIG>, the drive pinion <NUM> may optionally include or may be coupled to a drive pinion extension <NUM>. The drive pinion extension <NUM> may increase the axial length of the drive pinion <NUM>. In at least one configuration, the drive pinion extension <NUM> may be a separate component from the drive pinion <NUM> and may be coupled to the drive pinion <NUM> such that the drive pinion extension <NUM> is rotatable about the axis <NUM> with the drive pinion <NUM>. In addition, the drive pinion extension <NUM> may be fixedly positioned with respect to the drive pinion <NUM> such that the drive pinion extension <NUM> may not move along the axis <NUM> with respect to the drive pinion <NUM>. It is also contemplated that the drive pinion extension <NUM> may be integrally formed with the drive pinion <NUM>, in which case the drive pinion <NUM> may be a one-piece unitary component having a greater axial length.

In at least one configuration, the drive pinion extension <NUM> may extend from a first end <NUM> to a second end <NUM> and may include a socket <NUM> and the spline <NUM>. The socket <NUM> may extend from the first end <NUM> and may receive the drive pinion <NUM>. The second end <NUM> may be received inside and may be rotatably supported by a support bearing. The spline <NUM>, if provided, may facilitate coupling of the drive pinion extension <NUM> to a shift collar <NUM> that may be moveable along the axis <NUM> as will be discussed in more detail below.

Referring to <FIG>, the axle shafts <NUM> may transmit torque from the differential assembly <NUM> to corresponding wheel hubs and wheels. Two axle shafts <NUM> may be provided such that each axle shaft <NUM> extends through a different arm portion <NUM> of axle housing <NUM>. The axle shafts <NUM> may extend along and may be rotatable about an axis, such as the differential axis <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. Optionally, gear reduction may be provided between an axle shaft <NUM> and a wheel.

Referring to <FIG>, the electric motor module <NUM>, which may also be referred to as an electric motor, may be mounted to the differential carrier <NUM> and may be operatively connectable to the differential assembly <NUM>. For instance, the electric motor module <NUM> may provide torque to the differential assembly <NUM> via the transmission module <NUM> and the drive pinion <NUM> as will be discussed in more detail below. The electric motor module <NUM> may be primarily disposed outside the differential carrier <NUM>. In addition, the electric motor module <NUM> may be axially positioned between the axle housing <NUM> and the transmission module <NUM>. In at least one configuration, the electric motor module <NUM> may include a motor housing <NUM>, a coolant jacket <NUM>, a stator <NUM>, a rotor <NUM>, and at least one rotor bearing assembly <NUM>. The electric motor module <NUM> may also include a motor cover <NUM>.

The motor housing <NUM> may extend between the differential carrier <NUM> and the motor cover <NUM>. The motor housing <NUM> may be mounted to the differential carrier <NUM> and the motor cover <NUM>. For example, the motor housing <NUM> may extend from the mounting flange <NUM> of the differential carrier <NUM> to the motor cover <NUM>. The motor housing <NUM> may extend around the axis <NUM> and may define a motor housing cavity <NUM>. The motor housing cavity <NUM> may be disposed inside the motor housing <NUM> and may have a generally cylindrical configuration. The bearing support wall <NUM> of the differential carrier <NUM> may be located inside the motor housing cavity <NUM>. Moreover, the motor housing <NUM> may extend continuously around and may be spaced apart from the bearing support wall <NUM>. In at least one configuration, the motor housing <NUM> may have an exterior side <NUM>, an interior side <NUM>, a first end surface <NUM>, and a second end surface <NUM>.

The exterior side <NUM> may face away from the axis <NUM> and may define an exterior or outside surface of the motor housing <NUM>.

The interior side <NUM> may be disposed opposite the exterior side <NUM> and may face toward the axis <NUM>. The interior side <NUM> may be disposed at a substantially constant radial distance from the axis <NUM> in one or more configurations.

The first end surface <NUM> may extend between the exterior side <NUM> and the interior side <NUM>. The first end surface <NUM> may be disposed at an end of the motor housing <NUM> that may face toward the differential carrier <NUM>. For instance, the first end surface <NUM> may be disposed adjacent to the mounting flange <NUM> of the differential carrier <NUM> and may engage or contact the mounting flange <NUM>.

The second end surface <NUM> may be disposed opposite the first end surface <NUM>. As such, the second end surface <NUM> may be disposed at an end of the motor housing <NUM> that may face toward the motor cover <NUM> and may engage or contact the motor cover <NUM>.

The coolant jacket <NUM> may help cool or remove heat from the stator <NUM>. The coolant jacket <NUM> may be received in the motor housing cavity <NUM> of the motor housing <NUM> and may engage the interior side <NUM> of the motor housing <NUM>. The coolant jacket <NUM> may extend axially (e.g., in a direction along the axis <NUM>) between the differential carrier <NUM> and the motor cover <NUM>. For example, the coolant jacket <NUM> may extend axially from the differential carrier <NUM> to the motor cover <NUM>. In addition, the coolant jacket <NUM> may extend around the axis <NUM> and around the stator <NUM>. Accordingly, the stator <NUM> may be at least partially received in and may be encircled by the coolant jacket <NUM>. The coolant jacket <NUM> may extend in a radial direction from the stator <NUM> to the interior side <NUM> of the motor housing <NUM>. In at least one configuration, the coolant jacket <NUM> may include a plurality of channels through which coolant may flow.

The stator <NUM> may be received in the motor housing cavity <NUM>. The stator <NUM> may be fixedly positioned with respect to the coolant jacket <NUM>. For example, the stator <NUM> may extend around the axis <NUM> and may include stator windings that may be received inside and may be fixedly positioned with respect to the coolant jacket <NUM>.

The rotor <NUM> may extend around and may be rotatable about the axis <NUM>. In addition, the rotor <NUM> may extend around and may be supported by the bearing support wall <NUM>. The rotor <NUM> may be received inside the stator <NUM>, the coolant jacket <NUM>, and the motor housing cavity <NUM> of the motor housing <NUM>. The rotor <NUM> may be rotatable about the axis <NUM> with respect to the differential carrier <NUM> and the stator <NUM>. In addition, the rotor <NUM> may be spaced apart from the stator <NUM> but may be disposed in close proximity to the stator <NUM>.

One or more rotor bearing assemblies <NUM> may rotatably support the rotor <NUM>. For example, a rotor bearing assembly <NUM> may extend around and receive the bearing support wall <NUM> of the differential carrier <NUM> and may be received inside of the rotor <NUM>. The rotor <NUM> may be operatively connected to the drive pinion <NUM>. For instance, a coupling such as a rotor output flange <NUM> may operatively connect the rotor <NUM> to the transmission module <NUM>, which in turn may be operatively connectable to the drive pinion <NUM>.

The motor cover <NUM> may be mounted to the motor housing <NUM> and may be disposed opposite the axle housing <NUM> and the differential carrier <NUM>. For example, the motor cover <NUM> may be mounted to the second end surface <NUM> of the motor housing <NUM>. The motor cover <NUM> may be spaced apart from and may not engage the differential carrier <NUM>. The motor cover <NUM> may be provided in various configurations. In at least one configuration, the motor cover <NUM> may include a first side <NUM> and a second side <NUM>. The first side <NUM> may face toward and may engage the motor housing <NUM>. The second side <NUM> may be disposed opposite the first side <NUM>. The second side <NUM> may face away from the motor housing <NUM>. The motor cover <NUM> may also include a motor cover opening through which the drive pinion <NUM> may extend. The motor cover <NUM> may be integrated with the transmission module <NUM> or may be a separate component.

Referring to <FIG> and <FIG>, the transmission module <NUM> may transmit torque between the electric motor module <NUM> and the differential assembly <NUM>. As such, the transmission module <NUM> may be operatively connectable to the electric motor module <NUM> and the differential assembly <NUM>. In at least one configuration, the transmission module <NUM> may include a first transmission housing <NUM>, a second transmission housing <NUM>, and a transmission <NUM>. The first transmission housing <NUM> and the second transmission housing <NUM> may cooperate to define a transmission housing cavity <NUM> that may receive the transmission <NUM>.

The first transmission housing <NUM> may be mounted to the electric motor module <NUM>. For instance, the first transmission housing <NUM> may be mounted to the second side <NUM> of the motor cover <NUM>. As such, the motor cover <NUM> may separate the first transmission housing <NUM> from the motor housing <NUM>.

The second transmission housing <NUM> may be mounted to the first transmission housing <NUM>. For instance, the first transmission housing <NUM> may be mounted to and may engage or contact a side of the first transmission housing <NUM> that may face away from the motor cover <NUM>. As such, the first transmission housing <NUM> may separate the second transmission housing <NUM> from the motor cover <NUM>.

The transmission <NUM> may be operatively connected to the electric motor. In at least one configuration and as is best shown in <FIG>, the transmission <NUM> may be configured as a countershaft transmission that may include a set of drive pinion gears <NUM>, a first countershaft gear set <NUM>, and optionally a second countershaft gear set <NUM>.

The set of drive pinion gears <NUM> may be received in the transmission housing cavity <NUM> and may be arranged along the axis <NUM> between the first transmission housing <NUM> and the second transmission housing <NUM>. The set of drive pinion gears <NUM> may include a plurality of gears, some of which may be selectively coupled to the drive pinion <NUM>. In the configuration shown, the set of drive pinion gears <NUM> includes a first gear <NUM>, a second gear <NUM>, a third gear <NUM>, and a fourth gear <NUM>; however, it is to be understood that a greater or lesser number of gears may be provided.

The first gear <NUM> may extend around the axis <NUM> and may be disposed proximate the first transmission housing <NUM>. In at least one configuration, the first gear <NUM> may have a through hole that may receive the drive pinion <NUM>, an extension of the drive pinion <NUM> like the drive pinion extension <NUM>, or both. The first gear <NUM> may have a plurality of teeth that may be arranged around and may extend away from the axis <NUM>. The teeth of the first gear <NUM> may contact and may mate or mesh with teeth of a first countershaft gear that may be provided with the first countershaft gear set <NUM> and the second countershaft gear set <NUM> as will be discussed in more detail below. The first gear <NUM> may be operatively connected to the rotor <NUM> of the electric motor module <NUM> such that the rotor <NUM> and the first gear <NUM> are rotatable together about the axis <NUM>. For example, the first gear <NUM> may be fixedly positioned with respect to the rotor <NUM> or fixedly coupled to the rotor <NUM> such that the first gear <NUM> is not rotatable about the axis <NUM> with respect to the rotor <NUM>. It is contemplated that the first gear <NUM> may be fixedly mounted to or integrally formed with the rotor output flange <NUM>. As such, the first gear <NUM> may be continuously connected to the rotor <NUM> such that the first gear <NUM> and the rotor <NUM> may be rotatable together about the axis <NUM> but may not be rotatable with respect to each other. It is also contemplated that the first gear <NUM> may be selectively coupled to the drive pinion <NUM> or drive pinion extension <NUM>, such as with a shift collar. In addition, the first gear <NUM> may be decoupled from the drive pinion <NUM> and may be rotatable with respect to the drive pinion <NUM>. As such, a clutch or shift collar <NUM> may not connect the first gear <NUM> to the drive pinion <NUM> or the drive pinion extension <NUM>. The drive pinion extension <NUM>, if provided, may be received inside the first gear <NUM> and may be spaced apart from the first gear <NUM>. In at least one configuration, the first gear <NUM> may be axially positioned along the axis <NUM> between the second gear <NUM> and the electric motor module <NUM>.

Referring to <FIG>, the second gear <NUM> may extend around the axis <NUM>. In at least one configuration, the second gear <NUM> may have a through hole that may receive the drive pinion <NUM>, the drive pinion extension <NUM>, or both. The second gear <NUM> may have a plurality of teeth that may be arranged around and may extend away from the axis <NUM>. The teeth of the second gear <NUM> may contact and may mate or mesh with teeth of a second countershaft gear that may be provided with the first countershaft gear set <NUM> and the second countershaft gear set <NUM> as will be discussed in more detail below. As is best shown in <FIG>, the second gear <NUM> may also have inner gear teeth <NUM> that may extend toward the axis <NUM> and may be received in the through hole. The second gear <NUM> may have a different diameter than the first gear <NUM>. For example, the second gear <NUM> may have a larger diameter than the first gear <NUM> as is best shown in <FIG>. In at least one configuration, the second gear <NUM> may be axially positioned along the axis <NUM> between the first gear <NUM> and the third gear <NUM>. The drive pinion <NUM> or drive pinion extension <NUM>, if provided, may be received inside the second gear <NUM> and may be spaced apart from the second gear <NUM> in one or more configurations.

The third gear <NUM> may extend around the axis <NUM>. In at least one configuration, the third gear <NUM> may have a through hole that may receive the drive pinion <NUM>, the drive pinion extension <NUM>, or both. The third gear <NUM> may have a plurality of teeth that may be arranged around and may extend away from the axis <NUM>. The teeth of the third gear <NUM> may contact and may mate or mesh with teeth of a third countershaft gear that may be provided with the first countershaft gear set <NUM> and the second countershaft gear set <NUM> as will be discussed in more detail below. As is best shown in <FIG>, the third gear <NUM> may also have inner gear teeth <NUM> that may extend toward the axis <NUM> and may be received in the through hole. The third gear <NUM> may have a different diameter than the first gear <NUM> and the second gear <NUM>. For example, the third gear <NUM> may have a larger diameter than the first gear <NUM> and the second gear <NUM> as is best shown in <FIG>. In at least one configuration, the third gear <NUM> be axially positioned along the axis <NUM> between the second gear <NUM> and the fourth gear <NUM>. The drive pinion <NUM> or drive pinion extension <NUM>, if provided, may be received inside the third gear <NUM> and may be spaced apart from the third gear <NUM> in one or more configurations.

The fourth gear <NUM> may extend around the axis <NUM>. In at least one configuration, the fourth gear <NUM> may have a through hole that may receive the drive pinion <NUM>, the drive pinion extension <NUM>, or both. The fourth gear <NUM> may have a plurality of teeth that may be arranged around and may extend away from the axis <NUM>. The teeth of the fourth gear <NUM> may contact and may mate or mesh with teeth of a fourth countershaft gear that may be provided with the first countershaft gear set <NUM> and the second countershaft gear set <NUM> as will be discussed in more detail below. As is best shown in <FIG>, the fourth gear <NUM> may also have inner gear teeth <NUM> that may extend toward the axis <NUM> and may be received in the through hole. The fourth gear <NUM> may have a different diameter than the first gear <NUM>, the second gear <NUM>, and the third gear <NUM>, such as a larger diameter. In at least one configuration, the fourth gear <NUM> be axially positioned along the axis <NUM> further from the electric motor module <NUM> than the first gear <NUM>, the second gear <NUM>, and the third gear <NUM>. As such, the fourth gear <NUM> may be axially positioned proximate or adjacent to a side of the second transmission housing <NUM> that is disposed opposite the first transmission housing <NUM>. The drive pinion <NUM> or drive pinion extension <NUM> may be received inside the fourth gear <NUM> and may be spaced apart from the fourth gear <NUM> in one or more configurations.

Thrust bearings <NUM> may optionally be provided between members of the set of drive pinion gears <NUM>, between the first transmission housing <NUM> and the set of drive pinion gears <NUM>, between the second transmission housing <NUM> and the set of drive pinion gears <NUM>, or combinations thereof. For instance, a first thrust bearing <NUM> may be axially positioned between the first transmission housing <NUM> and the first gear <NUM>, a second thrust bearing <NUM> may be axially positioned between the first gear <NUM> and the second gear <NUM>, a third thrust bearing <NUM> may be axially positioned between the second gear <NUM> and the third gear <NUM>, a fourth thrust bearing <NUM> may be axially positioned between the third gear <NUM> and the fourth gear <NUM>, and a fifth thrust bearing <NUM> may be axially positioned between the fourth gear <NUM> and the second transmission housing <NUM>.

The first countershaft gear set <NUM> may be received in the transmission housing cavity <NUM> and may be in meshing engagement with the set of drive pinion gears <NUM>. The first countershaft gear set <NUM> may be rotatable about a first countershaft axis <NUM>. The first countershaft axis <NUM> may be disposed parallel or substantially parallel to the axis <NUM> in one or more embodiments. The first countershaft gear set <NUM> may include a first countershaft <NUM> and a plurality of gears. In the configuration shown, the plurality of gears of the first countershaft gear set <NUM> include a first countershaft gear <NUM>, a second countershaft gear <NUM>, a third countershaft gear <NUM>, and a fourth countershaft gear <NUM>; however, it is contemplated that a greater number of countershaft gears or a lesser number of countershaft gears may be provided.

The first countershaft <NUM> may be rotatable about the first countershaft axis <NUM>. For instance, the first countershaft <NUM> may be rotatably supported on the first transmission housing <NUM> and the second transmission housing <NUM> by corresponding bearing assemblies <NUM>. For example, first and second bearing assemblies <NUM> may be located near opposing first and second ends the first countershaft <NUM>, respectively. The first countershaft <NUM> may support and be rotatable with the first countershaft gear <NUM>, the second countershaft gear <NUM>, the third countershaft gear <NUM>, and the fourth countershaft gear <NUM>.

The first countershaft gear <NUM> may be fixedly disposed on the first countershaft <NUM> or fixedly mounted to the first countershaft <NUM>. As such, the first countershaft gear <NUM> may rotate about the first countershaft axis <NUM> with the first countershaft <NUM> and may not be rotatable with respect to the first countershaft <NUM>. For example, the first countershaft gear <NUM> may have a hole that may receive the first countershaft <NUM> and may be fixedly coupled to the first countershaft <NUM>. The first countershaft gear <NUM> may extend around the first countershaft axis <NUM> and may have a plurality of teeth that may be arranged around and may extend away from the first countershaft axis <NUM>. The teeth of the first countershaft gear <NUM> may contact and may mate or mesh with the teeth of the first gear <NUM>. In at least one configuration, the first countershaft gear <NUM> may be axially positioned along the first countershaft axis <NUM> between the first transmission housing <NUM> and the second countershaft gear <NUM> of the first countershaft gear set <NUM>.

The second countershaft gear <NUM> may be fixedly disposed on the first countershaft <NUM> or fixedly mounted to the first countershaft <NUM>. As such, the second countershaft gear <NUM> may rotate about the first countershaft axis <NUM> with the first countershaft <NUM> and may not be rotatable with respect to the first countershaft <NUM>. For example, the second countershaft gear <NUM> may have a hole that may receive the first countershaft <NUM> and may be fixedly coupled to the first countershaft <NUM>. The second countershaft gear <NUM> may extend around the first countershaft axis <NUM> and may have a plurality of teeth that may be arranged around and may extend away from the first countershaft axis <NUM>. The teeth of the second countershaft gear <NUM> may contact and may mate or mesh with the teeth of the second gear <NUM>. The second countershaft gear <NUM> may have a different diameter than the first countershaft gear <NUM> and the third countershaft gear <NUM>. In at least one configuration, the second countershaft gear <NUM> may be axially positioned along the first countershaft axis <NUM> between the first countershaft gear <NUM> of the first countershaft gear set <NUM> and the third countershaft gear <NUM> of the first countershaft gear set <NUM>.

The third countershaft gear <NUM> may be fixedly disposed on the first countershaft <NUM> or fixedly mounted to the first countershaft <NUM>. As such, the third countershaft gear <NUM> may rotate about the first countershaft axis <NUM> with the first countershaft <NUM> and may not be rotatable with respect to the first countershaft <NUM>. For example, the third countershaft gear <NUM> may have a hole that may receive the first countershaft <NUM> and may be fixedly coupled to the first countershaft <NUM>. The third countershaft gear <NUM> may extend around the first countershaft axis <NUM> and may have a plurality of teeth that may be arranged around and may extend away from the first countershaft axis <NUM>. The teeth of the third countershaft gear <NUM> may contact and may mate or mesh with the teeth of the third gear <NUM>. The third countershaft gear <NUM> may have a different diameter than the first countershaft gear <NUM> and the second countershaft gear <NUM>. In at least one configuration, the third countershaft gear <NUM> may be axially positioned along the first countershaft axis <NUM> between the second countershaft gear <NUM> of the first countershaft gear set <NUM> and the fourth countershaft gear <NUM> of the first countershaft gear set <NUM>.

The fourth countershaft gear <NUM> may be fixedly disposed on the first countershaft <NUM> or fixedly mounted to the first countershaft <NUM>. As such, the fourth countershaft gear <NUM> may rotate about the first countershaft axis <NUM> with the first countershaft <NUM> and may not be rotatable with respect to the first countershaft <NUM>. For example, the fourth countershaft gear <NUM> may have a hole that may receive the first countershaft <NUM> and may be fixedly coupled to the first countershaft <NUM> or may be integrally formed with the first countershaft <NUM>. The fourth countershaft gear <NUM> may extend around the first countershaft axis <NUM> and may have a plurality of teeth that may be arranged around and may extend away from the first countershaft axis <NUM>. The teeth of the fourth countershaft gear <NUM> may contact and may mate or mesh with the teeth of the fourth gear <NUM>. The fourth countershaft gear <NUM> may have a different diameter than the first countershaft gear <NUM>, the second countershaft gear <NUM>, and the third countershaft gear <NUM>. In at least one configuration, the fourth countershaft gear <NUM> may be axially positioned along the first countershaft axis <NUM> further from the electric motor module <NUM> than the third countershaft gear <NUM> of the first countershaft gear set <NUM>.

The second countershaft gear set <NUM>, if provided, may be received in the transmission housing cavity <NUM> and may be rotatable about a second countershaft axis <NUM>'. The second countershaft axis <NUM>' may be disposed parallel or substantially parallel to the axis <NUM> and the first countershaft axis <NUM> in one or more embodiments. The second countershaft gear set <NUM> may generally be disposed on an opposite side of the axis <NUM> from the first countershaft gear set <NUM> or may be disposed such that the first countershaft axis <NUM> and the second countershaft axis <NUM>' may be disposed at a common radial distance from the axis <NUM>. The first and second countershaft gear sets <NUM>, <NUM> may be positioned at any suitable rotational angle or position about the axis <NUM>.

The second countershaft gear set <NUM> may have the same or substantially the same configuration as the first countershaft gear set <NUM>. For example, the second countershaft gear set <NUM> may include a second countershaft <NUM>' that may be analogous to or may have the same structure as the first countershaft <NUM>. In addition, the second countershaft gear set <NUM> may include a plurality of gears that are rotatable with the second countershaft <NUM>'. In the configuration shown, the plurality of gears of the second countershaft gear set <NUM> include a first countershaft gear <NUM>', a second countershaft gear <NUM>', a third countershaft gear <NUM>', and a fourth countershaft gear <NUM>'; however, it is contemplated that a greater number of gears or a lesser number of gears may be provided. The first countershaft gear <NUM>', second countershaft gear <NUM>', third countershaft gear <NUM>', and the fourth countershaft gear <NUM>' of the second countershaft gear set <NUM> may be analogous to or may have the same structure as the first countershaft gear <NUM>, second countershaft gear <NUM>, third countershaft gear <NUM>, and the fourth countershaft gear <NUM>, respectively, of the first countershaft gear set <NUM>. The first countershaft gear <NUM>', second countershaft gear <NUM>', third countershaft gear <NUM>', and the fourth countershaft gear <NUM>' may be arranged along and may be rotatable about a second countershaft axis <NUM>' rather than the first countershaft axis <NUM> and may be fixed to the second countershaft <NUM>' rather than the first countershaft <NUM>.

The first gear <NUM> and the first countershaft gears <NUM>, <NUM>' may provide a different gear ratio than the second gear <NUM> and the second countershaft gears <NUM>, <NUM>', the third gear <NUM> and the third countershaft gears <NUM>, <NUM>', and the fourth gear <NUM> and the fourth countershaft gears <NUM>, <NUM>'. Gear ratios may be provided that are greater than <NUM>:<NUM>, less than <NUM>:<NUM>, equal (i.e., <NUM>:<NUM>), or combinations thereof.

The teeth of the drive pinion gears and the countershaft gears may be of any suitable type. As a non-limiting example, the meshing teeth of the members of the set of drive pinion gears <NUM>, the gears of the first countershaft gear set <NUM>, and the gears of the second countershaft gear set <NUM> may have a helical configuration.

Referring primarily to <FIG>, the shift mechanism <NUM> may selectively connect the transmission module <NUM> and the drive pinion <NUM>. For example, the shift mechanism <NUM> may operatively connect a member of the set of drive pinion gears <NUM> to the drive pinion <NUM> to provide torque at a desired gear ratio, and hence may change the torque transmitted between the electric motor module <NUM> and the differential assembly <NUM>. The shift mechanism <NUM> may couple one member of the set of drive pinion gears <NUM> at a time to the drive pinion <NUM>. The member of the set of drive pinion gears <NUM> that is coupled to the drive pinion <NUM> may be rotatable about the axis <NUM> with the drive pinion <NUM>.

The shift mechanism <NUM> may be received in or partially received in a shift mechanism housing cavity <NUM>, which is best shown in <FIG> and <FIG>. The shift mechanism housing cavity <NUM> may be partially defined by a housing of the axle assembly <NUM>, such as the second transmission housing <NUM>, and may be disposed proximate an end of the axle assembly <NUM>. Referring to <FIG> and <FIG>, a cover <NUM> may be mounted on the end of the second transmission housing <NUM> to help enclose the shift mechanism housing cavity <NUM>. The cover <NUM> is removed in <FIG>.

The shift mechanism <NUM> may have any suitable configuration. In at least one configuration such as is shown with reference to <FIG> and <FIG>, the shift mechanism <NUM> may include a shift collar <NUM>, an actuator <NUM>, a detent linkage <NUM>, a linkage <NUM>, and a biasing member <NUM>. The shift mechanism <NUM> may also include a first pin <NUM>, a second pin <NUM>, a first bushing <NUM>, a second bushing <NUM>, or combinations thereof.

Referring to primarily to <FIG> and <FIG>, the shift collar <NUM> may be rotatable about the axis <NUM> with the drive pinion <NUM>. In addition, the shift collar <NUM> may be moveable along the axis <NUM> with respect to the drive pinion <NUM>. The shift collar <NUM> may selectively connect a member of the set of drive pinion gears <NUM> to the drive pinion <NUM> as will be discussed in more detail below. The shift collar <NUM> may be at least partially received in the shift mechanism housing cavity <NUM> and may be extendable through components of the transmission <NUM>, such as the set of drive pinion gears <NUM>. In at least one configuration and as is best shown in <FIG>, the shift collar <NUM> may include a shift collar hole <NUM> and a shift collar spline <NUM>. The shift collar <NUM> may also include at least one shift collar gear <NUM> as is best shown in <FIG>.

Referring to <FIG>, the shift collar hole <NUM> may extend along the axis <NUM>. The drive pinion <NUM> or the drive pinion extension <NUM> may be received inside the shift collar hole <NUM>.

The shift collar spline <NUM> may couple the shift collar <NUM> to the drive pinion <NUM> or the drive pinion extension <NUM>. The shift collar spline <NUM> may be disposed in the shift collar hole <NUM>. The shift collar spline <NUM> may extend toward the axis <NUM> and may mate with a spline of the drive pinion <NUM> or the spline <NUM> of the drive pinion extension <NUM> that may have spline teeth that may extend away from the axis <NUM>. The mating splines may allow the shift collar <NUM> to move in an axial direction or along the axis <NUM> while inhibiting rotation of the shift collar <NUM> about the axis <NUM> with respect to the drive pinion <NUM>. Thus, the shift collar <NUM> may be rotatable about the axis <NUM> with the drive pinion <NUM> when the shift collar spline <NUM> mates with the spline of the drive pinion <NUM> or the drive pinion extension <NUM>.

Referring primarily to <FIG>, at least one shift collar gear <NUM> may be provided with the shift collar <NUM>. The shift collar gear <NUM> may have teeth that may be arranged around the axis <NUM> and that may extend away from the axis <NUM> and away from the shift collar hole <NUM>. The shift collar gear <NUM> may selectively engage a member of the set of drive pinion gears <NUM>.

Referring primarily to <FIG> and <FIG>, the actuator <NUM> may be configured to move the shift collar <NUM> along the axis <NUM> to selectively connect a member of the set of drive pinion gears <NUM> to the drive pinion <NUM>. The actuator <NUM> may be of any suitable type, such as an electrical, electromechanical, or mechanical actuator. In at least one configuration and as is best shown with reference to <FIG> and <FIG>, the actuator <NUM> may be mounted to a housing, such as the second transmission housing <NUM>. As is best shown in <FIG> and <FIG>, a portion of the actuator <NUM> may be rotatable about an actuator axis <NUM>. For instance, the actuator <NUM> may have an actuator shaft <NUM> that may extend along the actuator axis <NUM> and may be rotatable about the actuator axis <NUM>. As is best shown in <FIG>, the housing may define a hole <NUM>. The actuator shaft <NUM> may extend through the hole <NUM>. In addition, the actuator shaft <NUM> may be operatively connected to the detent linkage <NUM>.

Referring to <FIG> and <FIG>, the detent linkage <NUM> may be coupled to the actuator <NUM>. For instance, the detent linkage <NUM> may be coupled to the actuator shaft <NUM>, such as with mating splines, and may be rotatable about the actuator axis <NUM> with the actuator shaft <NUM>. In at least one configuration, the detent linkage <NUM> may include a detent linkage shaft <NUM> and a detent linkage plate <NUM>.

The detent linkage shaft <NUM> may extend along or may be disposed along the actuator axis <NUM>. The detent linkage shaft <NUM> may extend into the hole <NUM> in the second transmission housing <NUM>. In at least one configuration, the detent linkage shaft <NUM> may extend around and may receive the actuator shaft <NUM>.

The detent linkage plate <NUM> may extend from the detent linkage shaft <NUM>. For example, the detent linkage plate <NUM> may be disposed proximate an end of the detent linkage shaft <NUM> that may be disposed opposite the actuator <NUM> and may extend from the detent linkage shaft <NUM> in a direction that extends away from the actuator axis <NUM>. As is best shown in <FIG>, the detent linkage plate <NUM> may define a plurality of recesses <NUM>. The recesses <NUM> may be configured to receive a detent feature <NUM>, which is best shown in <FIG>. The detent feature <NUM> may inhibit rotation of the detent linkage <NUM> about the actuator axis <NUM> when the detent feature <NUM> is received in a recess <NUM>. For example, rotation of the detent linkage <NUM> may be inhibited when the detent feature <NUM> is in a recess <NUM> and a sufficient actuation force is not provided by the actuator <NUM> to overcome the rotational resistance exerted by the detent feature <NUM>. The detent linkage <NUM> may also be rotatable with respect to the linkage <NUM> as will be discussed in more detail below.

Referring primarily to <FIG>, <FIG>, and <FIG>, the linkage <NUM> may help operatively connect the actuator <NUM> to the shift collar <NUM>. In atleast one configuration, the linkage <NUM> may be positioned along the actuator axis <NUM> closer to the actuator <NUM> than the detent linkage <NUM> is positioned to the actuator <NUM>. The linkage <NUM> may be rotatable about the actuator axis <NUM>. In at least one configuration, the linkage <NUM> may define a linkage hole <NUM> through which the detent linkage shaft <NUM> may extend. The linkage <NUM> may also include an opening <NUM> that may facilitate coupling of the linkage <NUM> to a collar assembly <NUM>, which is best shown in <FIG>.

Referring primarily to <FIG>, <FIG>, and <FIG>, the biasing member <NUM> may operatively connect the detent linkage <NUM> to the linkage <NUM>. In addition, the biasing member <NUM> may control relative rotational movement between the detent linkage <NUM> and the linkage <NUM> (e.g., rotational movement of the linkage <NUM> with respect to the detent linkage <NUM>). For example, the biasing member <NUM> may permit the actuator shaft <NUM> and the detent linkage <NUM> to rotate about the actuator axis <NUM> with respect to the linkage <NUM> when the shift collar <NUM> is inhibited from moving along the axis <NUM> as will be discussed in more detail below. The biasing member <NUM> may be positioned along the actuator axis <NUM> between the detent linkage <NUM> and the linkage <NUM>. As is best shown in <FIG>, the biasing member <NUM> may also encircle the detent linkage shaft <NUM>. The biasing member <NUM> may also extend around the first bushing <NUM>. The biasing member <NUM> may have any suitable configuration. For instance, the biasing member <NUM> may be configured as a spring, such as a torsion spring. In at least one configuration, the biasing member <NUM> may include a first coil <NUM> and a second coil <NUM>.

Referring primarily to <FIG>, the first coil <NUM> may extend around the actuator axis <NUM>. For instance, the first coil <NUM> may extend in a spiral around the actuator axis <NUM>. The first coil <NUM> may be axially positioned closer to the linkage <NUM> than to the detent linkage <NUM>. For instance, the first coil <NUM> may extend axially from the linkage <NUM> to the second coil <NUM>. The first coil <NUM> may have a first tab <NUM>.

The first tab <NUM> may be disposed at an end of the first coil <NUM>. The first tab <NUM> may extend away from the actuator axis <NUM>. For instance, the first tab <NUM> may extend in a generally radial direction or along a line that extends away from the actuator axis <NUM>.

The second coil <NUM> may be attached to the first coil <NUM> or fixedly positioned with respect to the first coil <NUM>. For instance, the first coil <NUM> and the second coil <NUM> may be integrally formed, may be separate parts that are subsequently fixedly attached to each other, or may be fixedly positioned with respect to each other via the detent linkage shaft <NUM>. The second coil <NUM> may extend around the actuator axis <NUM>. For instance, the second coil <NUM> may extend in a spiral around the actuator axis <NUM>. The second coil <NUM> may be disposed closer to the detent linkage <NUM> than to the linkage <NUM>. For example, the second coil <NUM> may extend axially from the first coil <NUM> to the detent linkage plate <NUM>. The second coil <NUM> may have a second tab <NUM>.

The second tab <NUM> may be disposed at an end of the second coil <NUM>. The second tab <NUM> may extend away from the actuator axis <NUM>. For instance, the second tab <NUM> may extend in a generally radial direction or along a line that extends away from the actuator axis <NUM>. The first tab <NUM> and the second tab <NUM> may be rotationally offset from each other or positioned at different angular positions with respect to the actuator axis <NUM>. For instance, the first tab <NUM> and the second tab <NUM> may be positioned about the actuator axis <NUM> such that the first tab <NUM> is rotationally offset from the second tab <NUM>. As such, the first tab <NUM> and the second tab <NUM> may not be coplanar and may be disposed at different angular positions with respect to the actuator axis <NUM>.

The first pin <NUM> may extend from the detent linkage plate <NUM> toward the linkage <NUM>. The first pin <NUM> may be spaced apart from the detent linkage shaft <NUM> and the linkage <NUM>. The first pin <NUM> may engage the first tab <NUM>, the second tab <NUM>, or both, and may be positioned in the short circumferential region between the first tab <NUM> and the second tab <NUM>.

The second pin <NUM> may extend from the linkage <NUM> toward the detent linkage plate <NUM>. The second pin <NUM> may be spaced apart from the first pin <NUM> and the detent linkage <NUM>. The second pin <NUM> may engage the first tab <NUM>, the second tab <NUM>, or both, and may be positioned in the short circumferential region between the first tab <NUM> and the second tab <NUM>.

Referring to <FIG> and <FIG>, the first bushing <NUM> may be received inside the biasing member <NUM>. For instance, the first bushing <NUM> may extend around the detent linkage shaft <NUM> and may extend between the detent linkage shaft <NUM> and the biasing member <NUM>. The first bushing <NUM> may extend axially between the linkage <NUM> and the detent linkage plate <NUM>.

The second bushing <NUM> may be received inside the hole <NUM> in the housing. For instance, the second bushing <NUM> may extend radially between the detent linkage shaft <NUM> and the second transmission housing <NUM> as is best shown in <FIG>. The second bushing <NUM> may be axially positioned between the actuator <NUM> and the linkage <NUM>. In at least one configuration, the second bushing <NUM> may be axially positioned between a first washer <NUM> and a second washer <NUM>.

The first washer <NUM> may be disposed inside the shift mechanism housing cavity <NUM>. The first washer <NUM> may be axially positioned between the linkage <NUM> and the hole <NUM>. For instance, the first washer <NUM> may extend from the linkage <NUM> to a first end of the second bushing <NUM>, the second transmission housing <NUM>, or both.

The second washer <NUM> may be disposed outside of the shift mechanism housing cavity <NUM>. The second washer <NUM> may be axially positioned between the actuator <NUM> and the hole <NUM>. For instance, the second washer <NUM> may extend from the second transmission housing <NUM>, a second end of the second bushing <NUM>, or both, toward the actuator <NUM>. For example, the second washer <NUM> may engage a fastener <NUM> that may be coupled to the detent linkage shaft <NUM>. The fastener <NUM> and the second washer <NUM> may cooperate to inhibit axial movement of the detent linkage <NUM> along the actuator axis <NUM>, such as movement to the left from the perspective shown in <FIG>. The fastener <NUM> may be of any suitable type. For instance, the fastener <NUM> may be a snap ring, pin, or other component that may protrude from the detent linkage shaft <NUM> or otherwise inhibit the second washer <NUM> from moving away from the second bushing <NUM>.

Referring to <FIG> and <FIG>, the collar assembly <NUM> may receive the shift collar <NUM>. In addition, the collar assembly <NUM> may operatively connect the linkage <NUM> to the shift collar <NUM>. In at least one configuration, the collar assembly <NUM> may include a collar <NUM> and a shift block <NUM>.

The collar <NUM> may extend at least partially around the axis <NUM> in the shift collar <NUM>. For instance, the collar <NUM> may be configured as a ring that may encircle the shift collar <NUM>.

The shift block <NUM> may be fixedly positioned with respect to the collar <NUM>. The shift block <NUM> may be integrally formed with the collar <NUM> or may be provided as a separate component that is attached to the collar <NUM>. For instance, the shift block <NUM> may extend from an outside circumference of the collar <NUM> or a side of the collar <NUM>. A follower pin may extend from the shift block <NUM> two operatively connect the shift block <NUM> to the linkage <NUM>. The follower pin may be received in the opening <NUM> of the linkage <NUM>, which is best shown in <FIG>.

Operation of the shift mechanism <NUM> will now be discussed in more detail. As an overview, components of the shift mechanism <NUM> may typically move together when the shift collar <NUM> is free to move along the axis <NUM>. For instance, components such as the actuator shaft <NUM>, detent linkage <NUM>, linkage <NUM>, and the biasing member <NUM> may rotate together about the actuator axis <NUM> when the actuator shaft <NUM> is rotated and the shift collar <NUM> is free to move along the axis <NUM>. However, some of these components may move respect to each other when the shift collar <NUM> is not free to move along the axis <NUM>. For instance, the actuator shaft <NUM> and the detent linkage <NUM> may be rotatable with respect to the linkage <NUM> when the shift collar <NUM> is not free to move along the axis <NUM>. The shift collar <NUM> may not be free to move along the axis <NUM> when the rotational speed of the shift collar <NUM> about the axis <NUM> is not sufficiently synchronized with the rotational speed of a member of the set of drive pinion gears <NUM>. For instance, the shift collar <NUM> may be blocked from shifting or moving along the axis <NUM> when the teeth of the shift collar gear <NUM> are inhibited from entering the gaps between the inner gear teeth of a drive pinion gear or exiting the gaps between the inner gear teeth of a drive pinion gear. An example of movement when the shift collar <NUM> is not free to move along the axis <NUM> or is blocked from shifting is best understood with reference to <FIG> and <FIG>.

Referring to <FIG>, the shift mechanism <NUM> is shown in a first position. The first tab <NUM> of the first coil <NUM> and the second tab <NUM> of the second coil <NUM> may engage the first pin <NUM>, the second pin <NUM>, or both, when the shift collar <NUM> is free to move along the axis <NUM>. Such engagement may be maintained during rotation of the actuator shaft <NUM>, detent linkage <NUM>, linkage <NUM>, and biasing member <NUM> about the actuator axis <NUM>. Moreover, the first tab <NUM> and the second tab <NUM> may not move with respect to each other or the angular distance between the first tab <NUM> and the second tab <NUM> may remain substantially constant.

Referring to <FIG>, the shift mechanism <NUM> is shown in a second position that is associated with a blocked shift condition. The shift collar <NUM>, the linkage <NUM>, and the collar assembly <NUM> are shown in the same position as in <FIG> to represent a blocked shift condition in which the shift collar <NUM> is inhibited from moving to the right from the perspective shown or in a first direction along the axis <NUM>. The actuator shaft <NUM> and the detent linkage <NUM> are rotated counterclockwise about the actuator axis <NUM> from the perspective shown. The distance of rotation is merely an example and may differ from that shown.

Relative rotational movement of the detent linkage <NUM> with respect to the linkage <NUM> is accommodated by the biasing member <NUM>. The first pin <NUM> may remain in engagement with the second tab <NUM> but may be rotated to disengage or move away from the first tab <NUM>. The second pin <NUM> may remain in engagement with the first tab <NUM> but may be disengaged from the second tab <NUM>. This relative rotational movement may store potential energy in the biasing member <NUM>. The potential energy may be released when the blocked shift condition is no longer present, such as when the rotational speed of the shift collar <NUM> is sufficiently synchronized with the rotational speed of a member of the set of drive pinion gears <NUM> to permit axial movement of the shift collar <NUM>. As a result, the actuator <NUM> may complete its intended rotation of the actuator shaft <NUM> as if the shift collar <NUM> not blocked even when a blocked shift condition is present, thereby avoiding heating/overheating of the actuator <NUM> and the consumption of energy that would occur if the actuator <NUM> had to continuously work or exert force to attempt to complete shifting of the shift collar <NUM>. Moreover, sufficient potential energy may be stored in the biasing member <NUM> that may be released to complete a shift of the shift collar <NUM> when sufficient synchronization is obtained.

Claim 1:
A shift mechanism (<NUM>) comprising:
an actuator (<NUM>) that has an actuator shaft (<NUM>) that is rotatable about an actuator axis (<NUM>);
a detent linkage (<NUM>) that is rotatable about the actuator axis (<NUM>) with the actuator shaft (<NUM>);
a linkage (<NUM>) that is rotatable about the actuator axis (<NUM>);
a shift collar (<NUM>) that is operatively connected to the linkage (<NUM>) and moveable along an axis (<NUM>); and
a biasing member (<NUM>) that operatively connects the detent linkage (<NUM>) to the linkage (<NUM>) and that permits the actuator shaft (<NUM>) and the detent linkage (<NUM>) to rotate about the actuator axis (<NUM>) with respect to the linkage (<NUM>) when the shift collar (<NUM>) is inhibited from moving along the axis (<NUM>), wherein the detent linkage (<NUM>) has a detent linkage shaft (<NUM>) that extends along the actuator axis (<NUM>) and the biasing member (<NUM>) encircles the detent linkage shaft (<NUM>).