Axle assembly and method of control

A method of controlling an axle assembly. The method may include removing an actuator that is adapted to actuate a shift collar from a housing of the axle assembly, installing a positioning mechanism in place of the actuator, and securing the positioning mechanism to the housing of the axle assembly.

TECHNICAL FIELD

This relates to an axle assembly and a method of controlling an axle assembly.

BACKGROUND

An axle assembly having an electric motor module is disclosed in U.S. Pat. No. 11,038,396.

SUMMARY

A method of controlling an axle assembly is provided. The method includes removing an actuator from a housing of the axle assembly, installing a positioning mechanism in place of the actuator, and securing the positioning mechanism to the housing of the axle assembly. The actuator is adapted to actuate a shift collar.

Removing the actuator may include removing a fastener. The fastener may secure the actuator to the housing of the axle assembly. Securing the positioning mechanism may include reinstalling the fastener to secure the positioning mechanism to the housing of the axle assembly.

Removing the actuator may include moving the actuator along an actuator axis. Moving the actuator along the actuator axis may include moving the actuator away from the axle assembly. Moving the actuator along the actuator axis may disconnect an output shaft of the actuator from a cam of the axle assembly. The cam may be rotatable about the actuator axis.

The axle assembly may have a detent mechanism. Removing the actuator may include engaging the detent mechanism with the cam. Engaging the detent mechanism with the cam may inhibit rotation of the cam about the actuator axis.

The positioning mechanism may include a mounting plate and a shaft. The shaft may extend from the mounting plate. The cam may include a mounting feature. The mounting feature may be coupled to the actuator or the shaft. Installing the positioning mechanism may include engaging the shaft of the positioning mechanism with the mounting feature of the cam. Installing the positioning mechanism may include moving the shaft along the actuator axis into engagement with the mounting feature of the cam. The shaft may be engageable with the mounting feature at a single rotational position about the actuator axis.

The method may include moving the positioning mechanism after installing the positioning mechanism in place of the actuator. Moving the positioning mechanism may move the shift collar.

Moving the positioning mechanism may include attaching a tool to the positioning mechanism and exerting force with the tool. Exerting force with the tool may rotate the positioning mechanism.

Moving the positioning mechanism may occur before securing the positioning mechanism to the housing of the axle assembly.

Moving the positioning mechanism may include rotating the positioning mechanism about the actuator axis. The positioning mechanism may include a mounting plate and a shaft. The shaft may extend from the mounting plate. Rotating the positioning mechanism may include rotating the mounting plate and the shaft of the positioning mechanism together about the actuator axis.

Moving the positioning mechanism may occur after securing the positioning mechanism to the housing of the axle assembly. Moving the positioning mechanism may include rotating the shaft of the positioning mechanism with respect to the mounting plate of the positioning mechanism. Rotating the shaft may include rotating the shaft about the actuator axis.

The mounting plate may include an indicator mark. The indicator mark may indicate a position of the shift collar along the axis.

Installing the positioning mechanism in place of the actuator may include positioning the shaft of the positioning mechanism with respect to the mounting plate of the positioning mechanism. Positioning the shaft of the positioning mechanism with respect to the mounting plate may occur before installing the positioning mechanism in place of the actuator.

Positioning the shaft with respect to the mounting plate may include inserting the shaft into a hole in the mounting plate at a designated rotational position.

Securing the positioning mechanism may inhibit movement of the shift collar along an axis. Securing the positioning mechanism may hold the shift collar in a neutral position. A transmission of the axle assembly may be decoupled from a differential assembly of the axle assembly when the shift collar is in the neutral position.

DETAILED DESCRIPTION

It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly a second element could be termed a first element without departing from the scope of the various described embodiments. The first element and the second element are both elements, but they are not the same element.

Referring toFIG.1, an example of an axle assembly10is shown. The axle assembly10may be provided with a motor 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 motor vehicle may include a trailer for transporting cargo in one or more embodiments.

The axle assembly10is configured to 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. A single axle assembly is shown inFIGS.1and2. The axle assembly10includes an axle housing assembly20as is best shown inFIG.1. As is best shown, the axle assembly10may include a differential assembly22, a drive pinion24, at least one axle shaft26, an electric motor module28, a transmission module30, a shift mechanism32, or combinations thereof. As is best shown inFIGS.7,13,15, and17, a positioning mechanism34,34′,34″,34′″ is mountable to the axle assembly10to secure or facilitate positioning of the shift mechanism32.

The axle assembly10may be provided in various configurations. The axle assembly will primarily be described in the context of a configuration in which the electric motor module28is positioned between the differential assembly22and the transmission module30; however, it is to be understood that the axle assembly may be provided in other configurations, such as a configuration in which the differential assembly is positioned between the electric motor module and the transmission module or in which the electric motor module is remotely positioned from the axle assembly rather than being part of the axle assembly. In addition, the transmission module30is primarily discussed in the context of a configuration that has a planetary gear set; however, it is to be understood that the transmission module may be of any suitable type and may have a configuration that does not have a planetary gear set.

Axle Housing Assembly

Referring toFIG.1, the axle housing assembly20receives various components of the axle assembly10. In addition, the axle housing assembly20may facilitate mounting of the axle assembly10to the vehicle. In at least one configuration, the axle housing assembly20may include an axle housing40and a differential carrier42.

The axle housing40may receive and may support the axle shafts26. In at least one embodiment, the axle housing40may include a center portion50and at least one arm portion52.

The center portion50is disposed proximate the center of the axle housing40. The center portion50may define a cavity that may receive the differential assembly22. A lower region of the center portion50may at least partially define a sump portion that may contain or collect lubricant.

Referring toFIG.1, one or more arm portions52may extend from the center portion50. For example, two arm portions52may extend in opposite directions from the center portion50and away from the differential assembly22. The arm portions52may have similar configurations. For example, the arm portions52may each have a hollow tubular configuration that may extend around and may receive a corresponding axle shaft26and may help separate or isolate the axle shaft26or a portion thereof from the surrounding environment. An arm portion52or a portion thereof may be integrally formed with the center portion50. It is also contemplated that the arm portions52may be omitted.

Referring toFIGS.1and2, the differential carrier42is configured to support the differential assembly22. For example, the differential carrier42may include one or more bearing supports that may support a bearing like a roller bearing assembly that may rotatably support the differential assembly22. The differential carrier42may be mounted to the center portion50of the axle housing40. The differential carrier42may also facilitate mounting of the electric motor module28. In at least one configuration, the differential carrier42may include a bearing support wall60, which is best shown inFIG.2.

The bearing support wall60may support bearings that may rotatably support other components of the axle assembly10. For example, the bearing support wall60may support a bearing that may rotatably support the drive pinion24, a bearing that may rotatably support a rotor of the electric motor module28, or both. The bearing support wall60may extend in an axial direction away from the axle housing40and may extend around the axis70. The bearing support wall60may define a hole that may extend along or around the axis70and receive the drive pinion24and the bearings that rotatably support the drive pinion24. The bearing support wall60may be integrally formed with the differential carrier42or may be a separate component that is fastened to the differential carrier42.

Differential Assembly, Drive Pinion, and Axle Shafts

Referring toFIG.2, the differential assembly22is rotatable about a differential axis80and is configured to transmit torque to the axle shafts26and wheels. The differential assembly22is operatively connected to the axle shafts26and may permit the axle shafts26and wheels to rotate at different rotational speeds in a manner known by those skilled in the art. The differential assembly22may be partially received in the center portion50of the axle housing assembly20. The differential assembly22may have a ring gear82that may have teeth that mate or mesh with the teeth of the drive pinion24. Accordingly, the differential assembly22may receive torque from the drive pinion24via the ring gear82and transmit torque to the axle shafts26.

The drive pinion24may operatively connect the transmission module30to the differential assembly22. As such, the drive pinion24may transmit torque between the differential assembly22and the transmission module30. In at least one configuration, the drive pinion24may be rotatable about the axis70and may be rotatably supported inside another component, such as the bearing support wall60. The drive pinion24may include a gear portion90and a shaft portion92.

The gear portion90has a plurality of teeth that may mate with corresponding teeth on the ring gear82. The gear portion90may be integrally formed with the shaft portion92or may be provided as a separate component that may be fixedly disposed on the shaft portion92.

The shaft portion92extends from the gear portion90. For instance, the shaft portion92may extend away from the axle housing40and may have a spline94that mates with a corresponding spline on a shift collar170of the shift mechanism32as will be discussed in more detail below.

Referring toFIG.1, the axle shafts26are configured to transmit torque between the differential assembly22and corresponding wheel hubs and wheels. Two axle shafts26may be provided such that each axle shaft26extends through a different arm portion52of axle housing40. The axle shafts26may extend along and may be rotatable about an axis, such as the differential axis80. Each axle shaft26may have a first end and a second end. The first end may be operatively connected to the differential assembly22. 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 shaft26and a wheel.

Electric Motor Module

Referring toFIG.2, the electric motor module28, which may also be referred to as an electric motor, is configured to provide propulsion torque. The electric motor module28is operatively connectable to the differential assembly22. For instance, the electric motor module28may configured to provide torque to the differential assembly22via the transmission module30and the drive pinion24as will be discussed in more detail below. In at least one configuration, the electric motor module28may be mounted to the differential carrier42and may be primarily or completely disposed outside the differential carrier42. The electric motor module28may include a motor housing100, a coolant jacket102, a stator104, a rotor106, and at least one rotor bearing assembly108. The electric motor module28may also include a motor cover110.

The motor housing100facilitates mounting of the electric motor module28. In the configuration shown, the motor housing100extends between the differential carrier42and the motor cover110. The motor housing100may extend around the axis70and may define a motor housing cavity120. The bearing support wall60of the differential carrier42may be located inside the motor housing cavity120.

The coolant jacket102facilitates cooling or heat removal, such as cooling of the stator104. The coolant jacket102may be received in the motor housing cavity120of the motor housing100.

The stator104is received in the motor housing cavity120. The stator104may be fixedly positioned with respect to the coolant jacket102. For example, the stator104may extend around the axis70and may include stator windings that may be received inside and may be fixedly positioned with respect to the coolant jacket102.

The rotor106extends around and is rotatable about an axis, such as axis70. In addition, the rotor106may extend around and may be supported by the bearing support wall60. The rotor106may be received inside the stator104, the coolant jacket102, and the motor housing cavity120of the motor housing100. The rotor106may be rotatable about the axis70with respect to the differential carrier42and the stator104. In addition, the rotor106may be spaced apart from the stator104but may be disposed in close proximity to the stator104.

One or more rotor bearing assemblies108rotatably support the rotor106. For example, a rotor bearing assembly108may extend around and receive the bearing support wall60of the differential carrier42and may be received inside of the rotor106. The rotor106may be operatively connected to the drive pinion24. For instance, a coupling such as a rotor output flange130may operatively connect the rotor106to the transmission module30, which in turn may be operatively connectable to the drive pinion24.

The motor cover110may be mounted to the motor housing100and may be disposed opposite the axle housing40and the differential carrier42. The motor cover110may be integrated with the transmission module30or may be a separate component.

Transmission Module

Referring toFIG.2, the transmission module30is configured to transmit torque between the electric motor module28to the differential assembly22. Torque transmission may be bidirectional. As such, the transmission module30may be operatively connected to the electric motor module28and the differential assembly22.

The transmission module30may be received in a housing140. The housing140receives the shift mechanism32or a portion thereof. In at least one configuration, the housing140may be mounted to the motor cover110.

The transmission module30may provide gear reduction and multiple gear ratios between the rotor106and the drive pinion24. The transmission module30may be of any suitable type. For instance, the transmission module30may include a countershaft transmission, an epicyclic transmission (e.g., a transmission having a planetary gear set), or the like. A countershaft transmission may include a single countershaft or multiple countershafts. Examples of an axle assembly having a single countershaft transmission are disclosed in U.S. Pat. Nos. 11,002,352 and 11,209,072. Examples of an axle assembly having a dual countershaft transmission is disclosed in U.S. Pat. Nos. 10,989,288, 11,207,976, and 11,220,176. Examples of an axle assembly having an epicyclic transmission are disclosed in U.S. Pat. Nos. 11,038,396 and 11,428,297. The disclosures of the references in the preceding three sentences are hereby incorporated in their entirety by reference herein.

Referring toFIGS.2-4, an example of a transmission module30that has a planetary gear set is shown. In such a configuration, the transmission module30may include a sun gear150, planet gears152, a planetary ring gear154, and a planet gear carrier156.

The sun gear150is rotatable about the axis70. The sun gear150may be operatively connectable to the electric motor module28. The sun gear150may have teeth that face away from the axis70that mesh with the teeth of the planet gears152and an internal gear portion160that has teeth that extend toward the axis70that selectively mate or mesh with teeth of a shift collar as will be discussed in more detail below.

The planet gears152are rotatably disposed between the sun gear150and the planetary ring gear154. The planet gears152have teeth that face away from the axis70and mesh with teeth of the sun gear150and teeth of the planetary ring gear154.

The planetary ring gear154extends around the axis70. The planetary ring gear154may be stationary with respect to the axis70. For example, the planetary ring gear154may be received in and may be fixedly disposed on or with respect to the housing140.

The planet gear carrier156is rotatable about the axis70and rotatably supports the planet gears152. In at least one configuration, the planet gear carrier156may include a planet gear carrier gear portion162that has teeth that are arranged around the axis70and may extend toward the axis70.

Shift Mechanism

Referring toFIG.2, the shift mechanism32cooperates with the transmission module30to provide a desired gear reduction ratio to change the torque provided from the electric motor module28to the differential assembly22, and hence to the axle shafts26of the axle assembly10. For example, the transmission module30may provide a first drive gear ratio and a second drive gear ratio. The first drive gear ratio, which may be referred to as a low range gear ratio, may provide gear reduction from the electric motor module28to the differential assembly22and hence to the axle shafts26. As a nonlimiting example, the first drive gear ratio may provide a 2:1 gear ratio or more. The first drive gear ratio may provide increased torque to a vehicle traction wheel as compared to the second drive gear ratio.

The second drive gear ratio, which may be referred to as a high range gear ratio, may provide a different gear reduction ratio or lesser gear reduction ratio than the first drive gear ratio. For instance, the second drive gear ratio may provide a 1:1 gear ratio. The second drive gear ratio may facilitate faster vehicle cruising or a cruising gear ratio that may help improve fuel economy.

In addition, a neutral position or neutral drive gear ratio may be provided in which torque may not be provided to the differential assembly22by the electric motor module28. As such, torque may not be transmitted between the transmission module30and the drive pinion24when a shift collar is in the neutral position.

Referring toFIGS.5and6, the shift mechanism32may be received in the housing140and may include a shift collar170, a shift fork172or other linkage, a cam174, a detent mechanism176, and an actuator178.

The shift collar170is moveable along the axis70to provide a desired gear ratio as will be discussed in more detail below. In at least one configuration, the shift collar170may include a shift collar hole180, a shift collar spline182, a shift collar groove184, and a shift collar gear186.

The shift collar hole180may extend through the shift collar170and may extend around the axis70. The shift collar hole180may receive the shaft portion92of the drive pinion24.

The shift collar spline182may be disposed in the shift collar hole180and may mate with the spline94of the drive pinion24. The mating splines may allow the shift collar170to move in an axial direction or along the axis70while inhibiting rotation of the shift collar170about the axis70with respect to the drive pinion24. Thus, the shift collar170may be rotatable about the axis70with the drive pinion24.

The shift collar groove184receives the shift fork172, which connects the shift collar170to the cam174.

The shift collar gear186has teeth that may be arranged around the axis70and that may extend away from the axis70.

The shift collar170may selectively engage a gear ratio. More specifically, the shift collar170may move axially or in a direction that extends along the axis70between a first position, a second position, and a third position. Examples of these positions are illustrated inFIGS.2-4.

Referring toFIG.2, the shift collar170is shown in the first position. In the first position, the shift collar170may couple the planet gear carrier156to the drive pinion24. For example, the teeth of the shift collar gear186may mesh with the teeth of the planet gear carrier gear portion162of the planet gear carrier156. As such, torque that is provided by the electric motor module28may be transmitted through the rotor output flange130, sun gear150, planet gears152, and planet gear carrier156to the shift collar170and from the shift collar170to the drive pinion24.

Referring toFIG.3, the shift collar170is shown in a second position or neutral position. The second position may be axially positioned between the first position and the third position. In the second position, the shift collar170may not couple the transmission module30to the drive pinion24. For example, the teeth of the shift collar gear186may not mesh with the sun gear150or the planet gear carrier156. As such, torque is not transmitted between the electric motor module28and the differential assembly22in the neutral position.

Referring toFIG.4, the shift collar170is shown in the third position. In the third position, the shift collar170may couple the sun gear150to the drive pinion24. For example, the teeth of the shift collar gear186may mesh with the teeth of the internal gear portion160of the sun gear150. As such, torque that is provided by the electric motor module28may be transmitted through the rotor output flange130and sun gear150to the shift collar170and from shift collar170to the drive pinion24. The shift collar170may be disposed closer to the axle housing40when in the third position than when in the second position.

Referring toFIGS.5and6, the shift fork172extends between the shift collar170and the cam174. The shift fork172may be moveable along a shift axis190. For instance, the shift fork172may be slidable along a shift rail192that extends along the shift axis190. The shift axis190may be disposed substantially parallel to the axis70. The term “substantially parallel” as used herein means the same as or very close to parallel and includes features or axes that are within ±3° of being parallel each other. The shift fork172may have an engagement feature194that is configured to engage the cam174.

The cam174directly or indirectly connects the shift fork172to the actuator178. The cam174may be rotatable about an actuator axis200. Rotation of the cam174about the actuator axis200may move the shift fork172along the shift axis190. In the configuration shown, the engagement feature194of the shift fork172is offset from the actuator axis200and received in a window210of the cam174. The cam174may also include one or more detent engagement features212and a mounting feature214. The cam174is couplable to either the actuator178or the shaft of a positioning mechanism as will be discussed in more detail below.

The detent engagement features212are configured to engage the detent mechanism176. The detent engagement features212may have any suitable configuration, such as a male configuration, female configuration, or combinations thereof. In the configuration shown, the detent engagement features212are recesses that extend toward the actuator axis200. In this configuration, there is a first recess that corresponds to the first position of the shift collar170, a second recess that corresponds to the second (neutral) position, and a third recess that corresponds to the third position.

The mounting feature214may facilitate coupling of the cam174to another component, such as the actuator178or a positioning mechanism34,34′,34″,34″, so that the cam174is rotatable with another component. The mounting feature214may have any suitable configuration. For instance, the mounting feature214may have a male configuration, female configuration, or combinations thereof. The mounting feature214may be a spline or opening. The mounting feature may be asymmetric. For instance the mounting feature214may include splines that are arranged around the actuator axis200but may omit a spline tooth or include an enlarged spline tooth so that another component, such as a positioning mechanism34,34′,34″,34″, is only mountable to the mounting feature214at a particular rotational orientation about the actuator axis200. The same result may be achieved with asymmetric shapes, such as an asymmetric opening like a D-shaped opening in the cam174.

The detent mechanism176is engageable with the cam174to resist rotation of the cam174about the actuator axis200. For instance, the detent mechanism176may be received in the first, second, and third recesses of the cam174to hold the shift collar170in the first, second, and third positions, respectively, when sufficient torque is not exerted on the cam174to overcome the resistance exerted by the detent mechanism176. As such, the detent mechanism176may help hold the shift collar170in a desired position and may do so independent of the actuator178or when the actuator178is removed. The detent mechanism176may be mounted to the housing140.

The actuator178is configured to exert force to move the shift collar170along the axis70between the first, second, and third positions. The actuator178is removably mounted to the housing140. For example, the actuator178may be attached to the housing140with one or more fasteners220, such as bolts. The actuator178may have an output shaft222that may be rotatable about the actuator axis200. The output shaft222may be coupled to the cam174, such as with mating splines or asymmetric mating profiles that allow the output shaft222and the cam174to rotate together. Rotation of the output shaft222rotates the cam174, which in turn may actuate the shift fork172along the shift axis190, which in turn may move the shift collar170along the axis70. The actuator178may be of any suitable type. For example, the actuator178may be an electrical, electromechanical, pneumatic, or hydraulic actuator.

Referring toFIG.7, an example of a positioning mechanism34is shown. The positioning mechanism34may be used to hold the shift collar170in a desired position along the axis70. For instance, the positioning mechanism34may hold the shift collar170in the first position, the second position, or the third position. In addition, the positioning mechanism34may be moveable to move the shift collar170to a desired position along the axis70. In at least one configuration, the positioning mechanism34may include a mounting plate300, a shaft302, a seal304, or combinations thereof.

The mounting plate300facilitates mounting of the positioning mechanism34to the axle assembly10. In addition, the mounting plate300may facilitate movement and holding of the shift collar170as will be discussed in more detail below. In at least one configuration, the mounting plate300may have a footprint or mounting configuration that is the same as or compatible with the actuator178. As such, the mounting plate300may be installable on the housing140in place of the actuator178. In the configuration shown, the mounting plate300includes three through holes310; however, it is contemplated that a greater or lesser number of through holes may be provided. In addition, the mounting plate300may optionally include a tool attachment feature312, groove314, or both.

The tool attachment feature312may facilitate attachment or coupling of a tool to the mounting plate300. In the configuration shown, the tool attachment feature312has a female configuration; however it is contemplated that the tool attachment feature312may have a male configuration or combinations of male and female configurations.

The groove314is configured to receive the seal304, such as an O-ring, that may facilitate sealing between the mounting plate300and the axle assembly10. For instance, the seal304may be partially received in the groove314and may extend from the mounting plate300to the housing140to inhibit contaminants from entering the axle assembly10and to help retain lubricant inside the axle assembly10.

The shaft302extends from the mounting plate300. For example, the shaft302may extend from a side of the mounting plate300that is configured to face toward the axle assembly10when the positioning mechanism34is installed in place of the actuator178. The shaft302may be integrally formed with the mounting plate300or may be a separate component that is attached to the mounting plate300. The shaft302may extend along an axis, such as the actuator axis200when the positioning mechanism34is installed. For convenience in reference, the axis is primarily discussed as being the actuator axis200below, but it is to be understood that the axis may differ from the actuator axis200when the positioning mechanism is not installed on the axle assembly10. In at least one configuration, the shaft302may include a plurality of spline teeth322.

The spline teeth322may be arranged around the actuator axis200and may extend away from the actuator axis200. In the configuration shown, the spline teeth322are arranged in a repeating pattern with the exception of the omission of one spline tooth. This configuration may cooperate with the mounting feature214of the cam174to permit the shaft302to be inserted into the hole in the cam174at a specific rotational orientation or single rotational position about the actuator axis200. For instance, the mounting feature214of the cam174may be provided with an enlarged spline tooth that may only be insertable at the location where the spline tooth has been omitted from the shaft302.

Referring toFIGS.8-12, an example of a method of controlling the axle assembly10using the positioning mechanism34is shown.

As an overview, in an axle assembly that is driven with an electric motor there are times in which it is desirable to hold the shift collar in a predetermined position and prevent shifting of the shift collar. For instance, when a vehicle having an axle assembly that is driven with an electric motor needs to be towed, it may be desirable to move the shift collar to the neutral position and secure the shift collar accordingly. Securing the shift collar in the neutral position decouples the differential assembly from the transmission, which reduces rolling resistance since the transmission and rotor are decoupled from the vehicle wheels. The electric motor does not function as a generator when it is decoupled from the wheel vehicle wheels, which may help avoid unintended current flow to electrical components. Securing the shift collar in the neutral position may also prevent the shift collar from reengaging a gear ratio in a configuration that does not have a detent mechanism or when the detent mechanism does not function to inhibit rotation of the cam and hence does not inhibit axial movement of the shift collar.

It may also be desirable in some instances to move the shift collar to engage a gear ratio and to secure the shift collar accordingly. Doing so may allow the vehicle having the axle assembly to operate in a “limp home” mode in which the axle assembly is operative in a limited capacity and shifting of the axle assembly to a different gear ratio is prevented.

The example shown inFIGS.8-12is discussed in the context of a positioning mechanism that holds the shift collar in a neutral position; however, it is contemplated that the positioning mechanism could alternatively hold the shift collar “in gear” or in a position in which the shift collar connects the transmission to the drive pinion to provide a desired gear ratio. For instance, the shift collar could be moved (if necessary) to the first position or third position previously discussed and secured to prevent movement to a different position.

InFIG.8, a side view of a portion of the axle assembly10is shown with the actuator178mounted to the housing140and secured with three fasteners220configured as bolts.

InFIG.9, the actuator178is removed from the housing140of the axle assembly10. The actuator178may be removed from the housing140by removing the fasteners220. Fasteners220configured as threaded fasteners may be removed by rotating the fasteners220to unthread the fasteners220from a corresponding fastener hole in the housing140or to unthread the fasteners220from threaded studs that extend from the housing140. Then, the actuator178may be removed or disengaged from the housing140by moving the actuator178along the actuator axis200in a direction that extends away from the axle assembly10and the housing140. As a result, the output shaft222of the actuator178may disengage the cam174. For example, the output shaft222may move along the actuator axis200and disengage the mounting feature214of the cam174. Once removed, the actuator178may be set aside.

InFIG.10, the positioning mechanism34is installed in place of the actuator178. The positioning mechanism34may be installed in place of the actuator178by orienting the positioning mechanism34such that the shaft302is generally aligned with the actuator axis200and faces toward the axle assembly10. In addition, the positioning mechanism34may be rotated about the actuator axis200to align the spline teeth322with the mounting feature214in a manner that allows the spline teeth322to engage or mate with the mounting feature214. For instance, the positioning mechanism34may be rotated about the actuator axis200such that the shaft302may be inserted into the hole in the cam174. Then, the positioning mechanism34may be moved along the actuator axis200toward the axle assembly10to engage the shaft302and the cam174. For example, the positioning mechanism34may be moved along the actuator axis200to engage the spline teeth322and the mounting feature214.

In the example shown inFIG.10, the positioning mechanism34is illustrated in a rotational position about the actuator axis200in which the through holes310of the mounting plate300are not aligned with the holes in the housing140. In such a configuration, the positioning mechanism34will be rotated about the actuator axis200before the positioning mechanism34is secured to the axle assembly10. It is also contemplated that the positioning mechanism34may be disposed in a rotational position about the actuator axis200in which the through holes310of the mounting plate300are aligned with the holes of the housing140, in which case the positioning mechanism34need not be rotated about the actuator axis200before being secured to the axle assembly10.

Referring toFIG.11, the positioning mechanism34is moved after the positioning mechanism34is installed in place the actuator178. Moving the positioning mechanism34moves the shift collar170. In the configuration shown, moving the positioning mechanism34includes rotating the positioning mechanism34about the actuator axis200. In the example shown, the positioning mechanism34is rotated in a clockwise direction about the actuator axis200to move from the position shown inFIG.10to the position shown inFIG.11; however, it is contemplated that the positioning mechanism34may be rotated in a counterclockwise direction in other configurations. The positioning mechanism34may be rotated by grasping and rotating the mounting plate300by hand or by using a tool324. The tool324may be of any suitable type and may have any suitable configuration. For example, the tool324may be a lever, wrench, bar, pliers, driver bit, screwdriver, or the like. The tool324may be actuated by force that is exerted by a person or force that is exerted by device, such as a power tool that may be electrically or pneumatically powered, such as a drill or wrench. In the example shown, the tool324is illustrated as being a lever or socket wrench that is engaged with the tool attachment feature312of the mounting plate300. Force may be exerted with the tool324to move the positioning mechanism34, such as by rotating the positioning mechanism34about the actuator axis200. Movement of the positioning mechanism34may not be needed if the positioning mechanism34is in a securable position when the positioning mechanism34is installed.

Referring toFIG.12, the positioning mechanism34is secured to the axle assembly10. For instance, the positioning mechanism34may be secured to the housing140of the axle assembly10by reinstalling at least one fastener220. For instance, a fastener220that is configured as a threaded fastener may be inserted through a through hole310in the mounting plate300and threaded into a corresponding fastener hole in the housing140or threaded into engagement with a nut. Securing the positioning mechanism34in this manner may prevent the positioning mechanism34from rotating about the actuator axis200and thus may hold the shift collar170such that the shift collar170is inhibited from moving along the axis70. The shift collar170may still be free to rotate about the axis70with the drive pinion24when the positioning mechanism34is secured.

Referring toFIGS.13and14, another example of a positioning mechanism34′ is shown. In this configuration, the positioning mechanism34′ includes a mounting plate300′, a shaft302′, a seal304′, and a fastener306′.

The mounting plate300′ may be similar to or the same as the mounting plate300previously discussed but may include a shaft hole330′. The shaft hole330′ may extend along the actuator axis200. In at least one configuration, a plurality of shaft engagement features332′ may extend from the shaft hole330′.

A shaft engagement feature332′ facilitates positioning of the shaft302′. In the configuration shown, three shaft engagement features332′ are provided; however, it is contemplated that a greater or lesser number of shaft engagement features may be provided. A shaft engagement feature332′ may have any suitable configuration. For example, a shaft engagement feature332′ may be provided with a male configuration, female configuration, or combinations thereof. In the configuration shown, the shaft engagement features332′ are configured as notches that extend away from the actuator axis200. A shaft engagement feature332′ could be configured as a protrusion that extends toward the actuator axis200.

Each shaft engagement feature332′ corresponds with a different shift collar position when multiple shaft engagement feature332′ are provided. For example, a first shaft engagement feature332′ may correspond with a low gear ratio or the first position, a second shaft engagement feature332′ may correspond with the second position or neutral position, and a third shaft engagement feature332′ may correspond with the high gear ratio or third position.

One or more indicator markings334′ may optionally be provided to provide a visual indication of the position or gear ratio associated with a particular shaft engagement feature, and hence the position of the shift collar170. In the example shown, the first position or low gear ratio is designated with the L, the second or neutral position is designated with the letter N, and third position or high gear ratio is designated with the letter H.

The shaft302′ is receivable in the shaft hole330′ of the mounting plate300′. The shaft302′ may extend along the actuator axis200when the positioning mechanism34′ is installed in place of the actuator178. In at least one configuration, the shaft302′ may include spline teeth322as previously discussed. In addition, the shaft302′ may include a shaft flange340′, a shaft body342′, a shaft positioning feature344′, a shaft stud346′, or combinations thereof.

The shaft flange340′ may extend away from the actuator axis200. The shaft flange340′ may engage a side of the mounting plate300′ that faces toward the axle assembly10when the shaft302′ is assembled to the mounting plate300′.

The shaft body342′ may extend from the shaft flange340′. The shaft body342′ may be receivable in the shaft hole330′. The shaft body342′ may have a smaller diameter than the shaft flange340′. The shaft body342′ may extend axially from the shaft flange340′ to the shaft stud346′, if provided.

The shaft positioning feature344′ may be provided with the shaft body342′. The shaft positioning feature344′ may cooperate with the shaft engagement feature332′ to position the shaft302′ in a desired rotational position along the actuator axis200with respect to the mounting plate300′. In addition, the shaft positioning feature344′ may inhibit rotation of the shaft302′ about the actuator axis200with respect to the mounting plate300′. A shaft positioning feature344′ may be provided with any configuration that is compatible with a shaft engagement feature332′. For instance, a shaft positioning feature may be provided with a male configuration, female configuration, or combinations thereof. In the configuration shown, the shaft positioning feature344′ is configured as a protrusion that extends away from the actuator axis200. In such a configuration, the shaft positioning feature344′ may be received in one of the shaft engagement features332′ to inhibit rotation of the shaft302′ about the actuator axis200.

The shaft stud346′ facilitates mounting of the fastener306′. The shaft stud346′ may extend from the shaft body342′. In addition, the shaft stud346′ may extend along the actuator axis200. The shaft stud346′ or a portion thereof may be disposed outside of the shaft hole330′ and may extend in a direction that extends away from the shaft flange340′. The shaft stud346′ may be threaded and may facilitate mounting of a fastener306′ that is configured as a nut. Alternatively, the shaft stud346′ could be omitted in a configuration in which the fastener306′ is configured as a bolt. For instance, a threaded hole could be provided in the shaft body342′ into which a fastener that is configured as a bolt could be screwed into to secure the shaft302′ to the mounting plate300′.

The positioning mechanism34′ shown inFIGS.13and14, may be installed in a similar manner as the positioning mechanism34previously discussed. However, in this configuration the shaft302′ may be positioned with respect to the mounting plate300′ before installing the positioning mechanism34′ in place of the actuator178. For instance, the shaft302may be removed from the mounting plate300′, aligned with the shaft hole330′, and rotated about the axis to align the shaft positioning feature344′ with a desired shaft engagement feature332′. As an example, the shaft positioning feature344′ may be aligned with the shaft engagement feature332′ that is associated with the neutral position when it is desired to position and secure the shift collar170in the neutral position. Then, the shaft302′ may be moved along the axis into the shaft hole330′ such that the shaft engagement feature332′ mates with the shaft positioning feature344′, thereby inhibiting rotation of the shaft302′ with respect to the mounting plate300′. Then, the shaft302′ may be secured to the mounting plate300′ with the fastener306′ to inhibit the shaft302′ from moving along the axis with respect to the mounting plate300′, thereby resulting in the assembled configuration shown inFIG.13.

The same method steps shown inFIGS.8-12may then be employed to remove the actuator178, install the positioning mechanism34′ in place of the actuator178, move the positioning mechanism34′, if necessary, to move the shift collar170to a desired position along the axis70, and secure the positioning mechanism34′ to the axle assembly10. The resulting position of the shift collar170will be a function of the rotational position of the shaft302′ with respect to the mounting plate300′.

Referring toFIGS.15and16, another example of a positioning mechanism34″ is shown. In this configuration, the positioning mechanism34″ includes a mounting plate300″ and a shaft302″. The shaft302″ is rotatable with respect to the mounting plate300″ when the positioning mechanism34″ is secured to a housing of the axle assembly10in this configuration.

The mounting plate300″ includes one or more through holes310that facilitate mounting of the mounting plate300″ to a housing140of the axle assembly10as previously described. The mounting plate300″ also includes a shaft hole330′ that may be a through hole as previously described. The shaft302″ is received in the shaft hole330′ and may be rotatable about the actuator axis200with respect to the mounting plate300″ when the mounting plate300″ is secured to the axle assembly10. The mounting plate300″ may also include indicator markings334′ that provide a visual indication of the position of the shift collar170. In the configuration shown, the L, N, and H indicator markings334′ are provided as previously discussed. Alternatively or optionally, a contour change such as a notch or protrusion may be associated with each indicator marking to provide a tactile or visual reference.

The shaft302″ may be received in the shaft hole330′ and may include spline teeth322as previously discussed. In addition, the shaft302″ may include an engagement feature350″ and a pointer352″.

The engagement feature350″ may be configured to facilitate rotation of the shaft302″. The engagement feature350″ may have any suitable configuration. For instance, the engagement feature350″ is disposed along the actuator axis200and may have a male configuration, female configuration, or combinations thereof. The engagement feature350″ may be engaged or grasped by hand or with a tool. In the configuration shown inFIGS.15and16, the engagement feature350″ is configured with a hex head that may be engaged by a tool324, such as a socket or a wrench.

The pointer352″ may be configured to point to an indicator marking334′ to provide a visual or tactile indication as to position of the shift collar170that is associated with the rotational position of the shaft302″.

Referring toFIG.16, a shaft retainer354″ may be provided to inhibit movement of the shaft302″ along the actuator axis200and removal of the shaft302″ from the shaft hole330′ of the mounting plate300″. The shaft retainer354″ may have any suitable configuration. For instance, the shaft retainer354″ may be a clip, snap ring, pin, threaded fastener, or the like.

The method steps associated with this positioning mechanism34″ may differ somewhat from the method steps associate with the previous positioning mechanism34′ in that the positioning mechanism34″ may be secured to the housing140of the axle assembly10before the positioning mechanism34″ is moved to move the shift collar170. For instance, the actuator178may be removed from the housing140as previously discussed with respect toFIG.9and then positioning mechanism34″ may be installed in place of the actuator178as previously discussed with respect toFIG.10. Next, the positioning mechanism34″ may be secured to the axle assembly10in a similar manner as inFIG.12. For instance, the positioning mechanism34″ may be secured to the housing140of the axle assembly10by reinstalling at least one fastener220, such as by inserting a fastener220through a through hole310in the mounting plate300″ as previously described. Securing the positioning mechanism34″ prevents the mounting plate300″ from rotating about the actuator axis200. However, the shaft302″ is able to rotate about the actuator axis200with respect to the mounting plate300″.

Next, the positioning mechanism34″ may be moved after securing the positioning mechanism34″ to the housing of the axle assembly10to move the shift collar170along the axis70to a desired position. Thus in this context, moving the positioning mechanism34″ is associated with moving the shaft302″ of the positioning mechanism34″ rather than moving the mounting plate300″ or the entire positioning mechanism34″. For example, moving the positioning mechanism34″ may include rotating the shaft302″ about the actuator axis200with respect to the mounting plate300″. Force may be exerted on a portion of the shaft302″, such as the engagement feature350″, to rotate the shaft302to a desired position. InFIG.15, the shaft302is shown in the neutral position.

Referring toFIG.17, another configuration of a positioning mechanism34′″ is shown. This configuration is effectively the same as that shown inFIGS.15and16except that location of the engagement feature350′″ has changed. In this configuration, the engagement feature350′″ is illustrated as not being disposed along and not intersecting the actuator axis200. The engagement feature350′″ may have any of the configurations previously discussed with respect to engagement feature350″. In the configuration shown, the engagement feature350′″ is depicted as having a male configuration that is a protrusion having a generally rectangular profile rather than a hex head.

It is contemplated that a positioning mechanism having a rotatable shaft may be configured to resist rotation about the actuator axis200by itself. This may be beneficial when a detent mechanism176is not provided or is inoperative. Rotation of the shaft302″,302′″ about the actuator axis200with respect to the mounting plate300″,300′″ can be resisted in various ways, such as by friction between the shaft outside diameter and the mounting plate, friction between the shaft outside diameter and an intervening sleeve or other component that is disposed in the shaft hole in the mounting plate, friction due to axial compression against the mounting plate that resists rotation, by providing a different detent feature that allows the shaft or pointer to lock onto the mounting plate, by a fastener that is installed after the shaft is rotated to a desired position, or any combination of the above.

The present invention may allow the shift collar to be actuated independent of the actuator. This may allow the shift collar to be manually actuated when the actuator is inoperative, such as in a situation in which electrical power is not available to the actuator, when the actuator is stuck or partially stuck and is impaired from moving along the axis, or when a system fault exists that intentionally prevents the actuator from operating.

The present invention permits a shift collar to be actuated from outside the axle assembly to a neutral position or a particular gear ratio without extensive disassembly and reassembly of the axle assembly, which helps reduce time and associated costs.

The present invention may also allow the shift collar to be secured in a neutral position to decouple the differential assembly from the transmission and the electric motor. The shift collar may be moved and secured in the neutral position to facilitate towing or unpowered movement of the vehicle, such as towing of the vehicle. Moving the shift collar to the neutral position with a positioning mechanism as previously described is faster and less intrusive than alternatives like removing the axle shafts or decoupling the axle shafts from the wheel end assemblies and/or the differential assembly. Moreover, decoupling the axle shafts from the wheel end assemblies and/or the differential assembly is more difficult and complex when wheel end gear reduction is provided, such as with a set of reduction gears that operatively connect the axle shaft to a wheel hub. In such configurations, the wheel end gear reduction makes access to the axle shaft and disassembly more difficult and time-consuming, which may increase costs, require extensive reassembly, and may delay towing until disassembly can be completed as compared to the present invention.