Patent Description:
An axle assembly having a clutch collar is disclosed in <CIT>. <CIT> discloses a torque transmission apparatus that has a shift collar that has teeth with concave side surfaces that are engageable with convex lateral side surfaces of teeth of a drive component.

According to the invention, an axle assembly is provided as set out in claim <NUM>. Specific embodiments are provided in the dependent claims.

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 <NUM>.

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>, a drive pinion <NUM>, an electric motor module <NUM>, a gear reduction module <NUM>, and a shift mechanism <NUM>,.

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

Referring to <FIG> and <FIG>, the center portion <NUM> may be disposed proximate the center of the axle housing <NUM>. The center portion <NUM> may define a cavity that may receive the differential assembly <NUM>. As is best shown in <FIG>, a lower region of the center portion <NUM> may at least partially define a sump portion that may contain lubricant <NUM>. Splashed lubricant may flow down the sides of the center portion <NUM> and may flow over various internal components of the axle assembly <NUM> and gather in the sump portion.

Referring to <FIG>, one or more arm portions <NUM> may extend from the center portion <NUM>. For example, 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 substantially similar configurations. For example, the arm portions <NUM> may each have a hollow configuration or 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 be integrally formed with the center portion <NUM>. Alternatively, an arm portion <NUM> may be separate from the center portion <NUM>. In such a configuration, each arm portion <NUM> may be attached to the center portion <NUM> in any suitable manner, such as by welding or with one or more fasteners. An arm portion may rotatably support an associated wheel hub. It is also contemplated that the arm portions <NUM> may be omitted.

Referring to <FIG> and <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>. As is best shown with reference to <FIG>, <FIG> and <FIG>, the differential carrier <NUM> may include one or more bearing supports <NUM>, a mounting flange <NUM>, and a bearing support wall <NUM>.

Referring to <FIG> and <FIG>, the bearing support <NUM> may support a roller bearing assembly that may rotatably support the differential assembly <NUM>. For example, two bearing supports <NUM> may be received in the center portion <NUM> and may be located proximate opposite sides of the differential assembly <NUM>.

The mounting flange <NUM> may facilitate mounting of the electric motor module <NUM>. The mounting flange <NUM> may be configured as a ring that may extend outward and away from a first axis <NUM> and may extend around the first axis <NUM>. The mounting flange <NUM> may include a set of fastener holes <NUM>. Each fastener hole <NUM> may be configured to receive a fastener <NUM> that may secure the electric motor module <NUM> to the mounting flange <NUM>.

Referring to <FIG> and <FIG>, 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 first axis <NUM>. As such, the bearing support wall <NUM> may define a hole that may receive the drive pinion <NUM> and various other components as will be discussed in more detail below. In addition, the bearing support wall <NUM> may be radially positioned between the first axis <NUM> and the electric motor module <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 transmit torque to the axle shafts <NUM> and wheels and permit the axle shafts <NUM> and wheels to rotate at different velocities under various driving conditions. For instance, the differential assembly <NUM> may have a ring gear <NUM> that may engage and receive torque from the drive pinion <NUM>, may be operatively connected to the axle shafts <NUM>, and may transmit torque to the axle shafts <NUM> in a manner known by those skilled in the art. The differential assembly <NUM> and the ring gear <NUM> may be rotatable about an axis such as the wheel axis <NUM> or an axis that may be disposed substantially parallel to the wheel axis <NUM>.

Referring to <FIG> and <FIG>, the axle shafts <NUM> may transmit torque from the differential assembly <NUM> to corresponding wheel hubs and wheels. For example, two axle shafts <NUM> may be provided such that each axle shaft <NUM> may extend through a different arm portion <NUM> of axle housing <NUM>. The axle shafts <NUM> may extend along and may be rotated about the wheel axis <NUM> by the differential assembly <NUM>. Each axle shaft <NUM> may have a first end and a second end. The first end may be operatively connected to the differential assembly <NUM>. The second end may be disposed opposite the first end and may be operatively connected to a wheel. Optionally, gear reduction may be provided between an axle shaft <NUM> and a wheel.

Referring to <FIG>, the drive pinion <NUM> may provide torque to the ring gear <NUM> of the differential assembly <NUM>. The drive pinion <NUM> may also operatively connect a planetary gear set of the gear reduction module <NUM> to the differential assembly <NUM> as will be discussed in more detail below. The drive pinion <NUM> may extend along and may be rotatable about the first axis <NUM>. In addition, the drive pinion <NUM> may extend through the hole in the bearing support wall <NUM> and through a hole in a motor cover as will be discussed in more detail below. In at least one configuration, such as is best shown with reference to <FIG>, <FIG> and <FIG>, the drive pinion <NUM> may include a gear portion <NUM> and a shaft portion <NUM>.

The gear portion <NUM> may be disposed at or near an end of the shaft portion <NUM>. The gear portion <NUM> may have a plurality of teeth that may mesh with or mate with corresponding teeth on the ring gear <NUM>. The gear portion <NUM> may be integrally formed with the shaft portion <NUM> or may be provided as a separate component that may be fixedly disposed on the shaft portion <NUM>.

The shaft portion <NUM> may extend from the gear portion <NUM> in a direction that extends away from the axle housing <NUM>. As is best shown with reference to <FIG> and <FIG>, the shaft portion <NUM> may include a first outer surface <NUM>, a second outer surface <NUM>, a third outer surface <NUM>, a threaded portion <NUM>, and a spline <NUM>.

The first outer surface <NUM> may be disposed proximate the gear portion <NUM> and may be an outside circumference of a portion of the shaft portion <NUM>. A first drive pinion bearing <NUM> may be disposed on the first outer surface <NUM> and may rotatably support the drive pinion <NUM>. The first drive pinion bearing <NUM> may have any suitable configuration. For instance, the first drive pinion bearing <NUM> may be configured as a roller bearing assembly that may include a plurality of rolling elements that may be disposed between an inner race and an outer race. The inner race may extend around and may be disposed on the first outer surface <NUM>. The outer race may extend around the rolling elements and may be disposed on the bearing support wall <NUM> of the differential carrier <NUM> and may be received in the hole of the bearing support wall <NUM>.

The second outer surface <NUM> may be axially positioned between the first outer surface <NUM> and the third outer surface <NUM>. The second outer surface <NUM> may be an outside circumference of a portion of the shaft portion <NUM> and may have a smaller diameter than the first outer surface <NUM>. One or more spacer rings <NUM> may be disposed on the second outer surface <NUM>. The spacer rings <NUM> may be disposed between the inner races of the drive pinion bearings to inhibit axial movement of the drive pinion bearings toward each other.

The third outer surface <NUM> may be axially positioned between the second outer surface <NUM> and the threaded portion <NUM>. The third outer surface <NUM> may be an outside circumference of a portion of the shaft portion <NUM> and may have a smaller diameter than the second outer surface <NUM>. A second drive pinion bearing <NUM> may be disposed on the third outer surface <NUM> and may rotatably support the drive pinion <NUM>. The second drive pinion bearing <NUM> may have any suitable configuration. For instance, the second drive pinion bearing <NUM> may be configured as a roller bearing assembly that may include a plurality of rolling elements that may be disposed between an inner race and an outer race. The inner race may extend around and may be disposed on the third outer surface <NUM>. The outer race may extend around the rolling elements, may be disposed on the bearing support wall <NUM> of the differential carrier <NUM>, and may be received in the hole of the bearing support wall <NUM>.

The threaded portion <NUM> may be axially positioned between the third outer surface <NUM> and the spline <NUM>. The threaded portion <NUM> may facilitate installation of a preload nut <NUM>.

The preload nut <NUM> may be threaded onto the threaded portion <NUM> and may apply a preload force on the first drive pinion bearing <NUM>, the second drive pinion bearing <NUM>, or both.

The spline <NUM> may be disposed between the threaded portion <NUM> and an end of the shaft portion <NUM> that may be disposed opposite the gear portion <NUM>. The spline <NUM> may include a plurality of teeth. The teeth may be disposed substantially parallel to the first axis <NUM> and may mate with a corresponding spline on a shift collar of the shift mechanism <NUM> as will be discussed in more detail below.

Referring to <FIG>, the electric motor module <NUM> may be mounted to the differential carrier <NUM> and may provide torque to the differential assembly <NUM> via the drive pinion <NUM>. 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 gear reduction module <NUM> and the axle housing <NUM>. Main components of the electric motor module <NUM> are best shown with reference to <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>. 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>, at least one rotor bearing assembly <NUM>, and a motor cover <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, the motor housing <NUM> may extend between 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 a first axis <NUM> to define a motor housing cavity <NUM>. The motor housing cavity <NUM> may have a generally cylindrical configuration. The motor housing <NUM> may extend continuously around and may be spaced apart from the bearing support wall <NUM> of the differential carrier <NUM>.

Referring to <FIG> and <FIG>, the coolant jacket <NUM> may facilitate the circulation of a cooling fluid to help cool or remove heat from the stator <NUM>. The coolant jacket <NUM> may be received in the motor housing cavity <NUM> and may engage the interior surface of the motor housing <NUM>. The coolant jacket <NUM> may extend axially between the differential carrier <NUM> and the motor cover <NUM>. The coolant jacket <NUM> may receive the stator <NUM>.

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

Referring to <FIG>, <FIG> and <FIG>, the rotor <NUM> may extend around the first axis <NUM> and may be received inside the stator <NUM> and the motor housing <NUM>. The rotor <NUM> may be rotatable about the first axis <NUM> with respect to the differential carrier <NUM> and the stator <NUM>. The rotor <NUM> may be spaced apart from the stator <NUM> but may be disposed close to the stator <NUM>. The rotor <NUM> may include magnets or ferromagnetic material that may facilitate the generation of electrical current. The rotor <NUM> may extend around and may be supported by the bearing support wall <NUM>. The rotor <NUM> may be operatively connected to the drive pinion <NUM> between the end of the bearing support wall <NUM> and the motor cover <NUM>, such as with a rotor output flange <NUM> as will be discussed in more detail below.

At least one rotor bearing assembly <NUM> may rotatably support the rotor <NUM>. The rotor bearing assembly <NUM> may receive the bearing support wall <NUM> of the differential carrier <NUM> and may be received inside of the rotor <NUM>. The rotor bearing assembly <NUM> may have any suitable configuration. For instance, the rotor bearing assembly <NUM> may include a plurality of rolling elements that may be disposed between an inner race and an outer race. The inner race may extend around and may receive the bearing support wall <NUM> of the differential carrier <NUM>. The outer race may extend around the rolling elements and may be disposed on the rotor <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the motor cover <NUM> may be mounted to the motor housing <NUM> and may be disposed opposite the axle housing <NUM>. For example, the motor cover <NUM> may be mounted to an end of the motor housing <NUM> that may face away from the differential carrier <NUM>. The motor cover <NUM> may be provided in various configurations. In at least one configuration, the motor cover <NUM> may define a motor cover opening that may be a through hole that may extend around the first axis <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the rotor output flange <NUM> may operatively connect or couple the electric motor module <NUM> to the gear reduction module <NUM>. For example, the rotor output flange <NUM> may couple the rotor <NUM> to a sun gear <NUM> of the gear reduction module <NUM> as will be discussed in more detail below. The rotor output flange <NUM> may be fixedly coupled to or fixedly mounted to the rotor <NUM>. As such, the rotor output flange <NUM> may rotate about the first axis <NUM> with the rotor <NUM>. In addition, the rotor output flange <NUM> may extend through the motor cover opening of the motor cover <NUM>. In at least one configuration, the rotor output flange <NUM> may include a tubular body <NUM> and a flange portion <NUM>.

The tubular body <NUM> may extend around the first axis <NUM> and may define a rotor output flange hole <NUM>. The rotor output flange hole <NUM> may be a through hole that may extend along and may be centered about the first axis <NUM>. The drive pinion <NUM> may extend through the rotor output flange hole <NUM> and may be spaced apart from the rotor output flange <NUM>. As is best shown in <FIG>, the sun gear <NUM> of the gear reduction module <NUM> may be partially received in the rotor output flange <NUM> and hence may be partially received in the rotor output flange hole <NUM>. In at least one configuration, the tubular body <NUM> may include a rotor output flange spline <NUM>, a spigot bearing support surface <NUM>, and a rotary disc support surface <NUM>.

The rotor output flange spline <NUM> may be disposed in the rotor output flange hole <NUM>. The rotor output flange spline <NUM> may have teeth that may be arranged around the first axis <NUM> and may extend toward the first axis <NUM>. The teeth of the rotor output flange spline <NUM> may mate with a spline of the sun gear <NUM> such that the rotor output flange <NUM> may rotate about the first axis <NUM> with the sun gear <NUM> and the rotor <NUM>.

The spigot bearing support surface <NUM> may be axially positioned between the flange portion <NUM> and the second end of the tubular body <NUM>. Referring to <FIG>, <FIG> and <FIG>, the spigot bearing support surface <NUM> may be configured to support a spigot bearing assembly <NUM>. the spigot bearing assembly <NUM> may receive the rotor output flange <NUM> and may rotatably support the rotor output flange <NUM>. The spigot bearing assembly <NUM> may help inhibit deflection of the rotor <NUM>, such as deflection with respect to the first axis <NUM>. As such, the spigot bearing assembly <NUM> may help align or center the rotor <NUM> about the first axis <NUM> and may help improve the stability of the rotor <NUM> and maintain a desired air gap between the rotor <NUM> and the stator <NUM>. The spigot bearing assembly <NUM> may be received inside the hole of the motor cover <NUM>. In at least one configuration, the spigot bearing assembly <NUM> may extend between the motor cover <NUM> and the rotor output flange <NUM>.

The rotary disc support surface <NUM> may be disposed opposite the rotor output flange hole <NUM> and may be axially positioned between the spigot bearing support surface <NUM> and the second end of the tubular body <NUM>. The rotary disc support surface <NUM> may support a rotary disc <NUM>, which may also be referred to as a resolver rotor.

Referring to <FIG> and <FIG>, the rotary disc <NUM> may be fixedly disposed on the rotor output flange <NUM>. As such, the rotary disc <NUM> may rotate about the first axis <NUM> with the rotor <NUM>. The rotary disc <NUM> may be axially positioned between the spigot bearing assembly <NUM> and the second end of the rotor output flange <NUM>. As is best shown in <FIG>, the rotary disc <NUM> may have a non-cylindrical outer surface that may face away from the first axis <NUM> that may include a plurality of protrusions that may extend away from the first axis <NUM>. The protrusions may be arranged in a repeating pattern around the first axis <NUM>.

The flange portion <NUM> may be disposed between the first end and the second end of the tubular body <NUM>. The flange portion <NUM> may extend from the tubular body <NUM> in a direction that extends away from the first axis <NUM>. The flange portion <NUM> may be fixedly coupled to the rotor <NUM>. For instance, the flange portion <NUM> may include a set of holes that may be arranged around the first axis <NUM> and that may receive fasteners, such as bolts, that may extend through the holes to couple the flange portion <NUM> to the rotor <NUM>.

Referring to <FIG>, <FIG> and <FIG>, a first sensor <NUM> may be associated with the electric motor module <NUM>. The first sensor <NUM>, which may also be referred to as a resolver stator, may function as a sensor that may provide a signal indicative of rotation of the rotor <NUM> or the rotational position of the rotor <NUM>. For example, the first sensor <NUM> may detect the position of the rotary disc <NUM>, such as by detecting the presence or absence of the protrusions of the rotary disc <NUM> or may detect rotation of the rotary disc <NUM>. The first sensor <NUM> may be of any suitable type. For example, the first sensor <NUM> may be an analog resolver or a digital resolver, such as a rotary encoder.

The first sensor <NUM> may generally be configured as a ring that may extend around the first axis <NUM>. In at least one configuration, the first sensor <NUM> may be mounted to the motor cover <NUM>. The first sensor <NUM> may be electrically connected to an electrical power source and a controller <NUM> or axle control module that may control operation of the electric motor module <NUM>.

Referring to <FIG>, the gear reduction module <NUM> may transmit torque from the electric motor module <NUM> to the differential assembly <NUM>. As such, the gear reduction module <NUM> may be operatively connected to the electric motor module <NUM> and the differential assembly <NUM>. The gear reduction module <NUM> may be disposed outside of the differential carrier <NUM> and may be primarily disposed outside of the electric motor module <NUM>, thereby providing a modular construction that may be mounted to the electric motor module <NUM> when gear reduction is desired. Such a configuration may facilitate standardized configurations of the differential carrier <NUM> and/or the electric motor module <NUM>.

The gear reduction module <NUM> may be disposed adjacent to the motor cover <NUM>. In addition, the gear reduction module <NUM> may be at least partially received in a housing, such as a shift mechanism housing <NUM> that may be mounted to the motor cover <NUM>.

The gear reduction module <NUM> may be provided in various configurations, such as planetary gear set configurations and non-planetary gear set configurations. Referring to <FIG>, <FIG> and <FIG>, an example of a gear reduction module <NUM> that has a planetary gear set <NUM> is shown. In such a configuration, the gear reduction module <NUM> may include a sun gear <NUM>, planet gears <NUM>, a planetary ring gear <NUM>, and a planet gear carrier <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the sun gear <NUM> may be disposed proximate the center of the planetary gear set <NUM> and may be rotatable about the first axis <NUM>. The sun gear <NUM> may be operatively connectable to the electric motor module <NUM>. In addition, the sun gear <NUM> may extend into the motor cover opening of the motor cover <NUM>. As is best shown primarily with reference to <FIG> and <FIG>, the sun gear <NUM> may be a hollow tubular body that may include a first end surface <NUM>, a second end surface <NUM>, a sun gear hole <NUM>, a sun gear spline <NUM>, a first gear portion <NUM>, and a second gear portion <NUM>.

The first end surface <NUM> may be disposed at an end of the sun gear <NUM> that may face toward the axle housing <NUM>.

The second end surface <NUM> may be disposed at an end of the sun gear <NUM> that may face away from the axle housing <NUM>. As such, the second end surface <NUM> may be disposed opposite the first end surface <NUM>. A thrust bearing <NUM> may extend from the second end surface <NUM> to the planet gear carrier <NUM> to help inhibit axial movement of the sun gear <NUM> and facilitate rotation of the sun gear <NUM> with respect to the planet gear carrier <NUM>.

The sun gear hole <NUM> may extend from the first end surface <NUM> to the second end surface <NUM>. The sun gear hole <NUM> may extend along and may be centered about the first axis <NUM>. The drive pinion <NUM> may extend through the sun gear hole <NUM> and may be spaced apart from the sun gear <NUM>.

The sun gear spline <NUM> may facilitate coupling of the sun gear <NUM> to a rotor output flange <NUM>. In at least one configuration, the sun gear spline <NUM> may be disposed opposite the sun gear hole <NUM> and may extend from or may be disposed proximate the first end surface <NUM>. As such, the sun gear spline <NUM> may be received inside the rotor output flange <NUM> and may mesh with the rotor output flange spline <NUM>. It is also contemplated that the sun gear spline <NUM> may be disposed in the sun gear hole <NUM> and the rotor output flange <NUM> may be received inside the sun gear <NUM>.

The first gear portion <NUM> may be disposed in the sun gear hole <NUM>. For example, the first gear portion <NUM> may be disposed proximate the second end surface <NUM> of the sun gear <NUM>. Teeth of the first gear portion <NUM> may be arranged around the first axis <NUM> and may extend toward the first axis <NUM> and may be configured to mesh with teeth of a shift collar <NUM> as will be discussed in more detail below.

The second gear portion <NUM> may be disposed opposite the first gear portion <NUM>. The second gear portion <NUM> may be disposed proximate the second end surface <NUM> of the sun gear <NUM>. The second gear portion <NUM> may have teeth that may mesh with teeth of the planet gears <NUM>. The teeth of the second gear portion <NUM> may be arranged around the first axis <NUM> and may extend away from the first axis <NUM>.

The planet gears <NUM> may be rotatably disposed between the sun gear <NUM> and the planetary ring gear <NUM>. Each planet gear <NUM> may have a hole and a set of teeth. The hole may be a through hole that may extend through the planet gear <NUM>. The set of teeth may be disposed opposite the hole. The set of teeth may mesh with teeth of the second gear portion <NUM> of the sun gear <NUM> and teeth on the planetary ring gear <NUM>. Each planet gear <NUM> may be configured to rotate about a different planet gear axis of rotation. The planet gear axes of rotation may extend substantially parallel to the first axis <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the planetary ring gear <NUM> may extend around the first axis <NUM> and may receive the planet gears <NUM>. The planetary ring gear <NUM> may include a set of planetary ring gear teeth that may extend toward the first axis <NUM> and may mesh with teeth on the planet gears <NUM>. The planetary ring gear <NUM> may be stationary with respect to the first axis <NUM>. For example, the planetary ring gear <NUM> may be received in and may be fixedly disposed on the motor cover <NUM>, the shift mechanism housing <NUM>, or combinations thereof.

The planet gear carrier <NUM> may be rotatable about the first axis <NUM> and may rotatably support the planet gears <NUM>. In at least one configuration, the planet gear carrier <NUM> may include a planet gear carrier hole <NUM>, a planet gear carrier ring <NUM>, a planet gear carrier gear portion <NUM>, and at least one planet gear carrier flange <NUM>.

The planet gear carrier hole <NUM> may be a through hole that may extend through planet gear carrier <NUM>. The planet gear carrier hole <NUM> may extend along and may be centered about the first axis <NUM>.

The planet gear carrier ring <NUM> may at least partially define the planet gear carrier hole <NUM>. The planet gear carrier ring <NUM> may extend around the first axis <NUM> and may extend in an axial direction away from the second flange. The planet gear carrier ring <NUM> may be configured to support a support bearing <NUM> and a tone ring <NUM>. The support bearing <NUM> may rotatably support the planet gear carrier <NUM> on a stationary component, such as the shift mechanism housing. The tone ring <NUM> may have a plurality of teeth and may receive and may be fixedly disposed on the planet gear carrier ring <NUM>.

The planet gear carrier gear portion <NUM> may be disposed in the planet gear carrier ring <NUM> and may extend into the planet gear carrier hole <NUM>. Teeth of the planet gear carrier gear portion <NUM> may be arranged around the first axis <NUM> and may extend toward the first axis <NUM>.

One or more planet gear carrier flanges <NUM> may extend away from the first axis <NUM> and may help support the planet gears <NUM>. For instance, a planet pin <NUM> may rotatably support each planet gear <NUM> and may extend from at least one planet gear carrier flange <NUM>.

Referring to <FIG>, the shift mechanism <NUM> may be disposed at an end of the axle assembly <NUM> that may be disposed opposite the axle housing <NUM>. The shift mechanism <NUM> may be disposed on the motor cover <NUM>.

The gear reduction module <NUM> may cooperate with the shift mechanism <NUM> to provide a desired gear reduction ratio to change the torque provided from the electric motor module <NUM> to the differential assembly <NUM>, and hence to the axle shafts <NUM> of the axle assembly <NUM>. For example, the gear reduction module <NUM> may 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 module <NUM> to the differential assembly <NUM> and hence to the axle shafts <NUM>. As a nonlimiting example, the first drive gear ratio may provide a <NUM>:<NUM> 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 <NUM>:<NUM> 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 assembly <NUM> by the electric motor module <NUM> or may not be transmitted between the electric motor module <NUM> and the differential assembly <NUM>. For instance, torque may not be transmitted between the gear reduction module <NUM> and the drive pinion <NUM> when a shift collar is in the neutral position.

Referring to <FIG>, <FIG> and <FIG>, the shift mechanism <NUM> may include a shift mechanism housing <NUM>, an actuator <NUM>, and a shift collar <NUM>.

The shift mechanism housing <NUM> may be disposed on the motor cover <NUM> or may be fixedly positioned with respect to the motor cover <NUM>. For example, the shift mechanism housing <NUM> may be mounted to a side of the motor cover <NUM> that may be disposed opposite the differential carrier <NUM>. The shift mechanism housing <NUM> may at least partially receive the gear reduction module <NUM>. In addition, the shift mechanism housing <NUM> may facilitate mounting of the actuator <NUM> and may at least partially receive the shift collar <NUM>. The shift mechanism housing <NUM> may include an end plate <NUM> that may be disposed opposite the axle housing <NUM> and that may be removably mounted to the shift mechanism housing <NUM>.

Referring to <FIG> and <FIG> an example of an actuator <NUM> that may actuate the shift collar <NUM> shown. The actuator <NUM> may be of any suitable type and may have any suitable configuration. For instance, the actuator <NUM> may be an electrical, electromechanical, pneumatic or hydraulic actuator. In at least one configuration, the actuator <NUM> may have an output shaft that may be rotatable about an axis. A cam <NUM> may be mounted to the output shaft and may rotate with the output shaft. The cam <NUM> may operatively connect the actuator <NUM> to the linkage <NUM>. As such, rotation of the output shaft may actuate the cam <NUM>, which in turn may actuate the linkage <NUM> and the shift collar <NUM> along the first axis <NUM>. The actuator <NUM> may be mounted on the shift mechanism housing <NUM>.

The actuator <NUM> may move the shift collar <NUM> along the first axis <NUM> between a plurality of positions to selectively couple the shift collar <NUM> to the gear reduction module <NUM> or to decouple the shift collar <NUM> from the gear reduction module <NUM>. For instance, the actuator <NUM> may move the shift collar <NUM> along the first axis <NUM> between the first, second, and third positions. Examples of these positions are illustrated in <FIG>, <FIG>, and <FIG>. As is best shown in <FIG>, the actuator <NUM> may include an actuator sensor <NUM> that may provide a signal that may be indicative of the position of the actuator <NUM> and hence the position of the shift collar <NUM>.

Referring to <FIG> and <FIG>, the shift collar <NUM> is shown in the first position. In the first position, the shift collar <NUM> may couple the planet gear carrier <NUM> to the drive pinion <NUM>. For example, the teeth of the shift collar gear <NUM> may mesh with the teeth of the planet gear carrier gear portion <NUM> of the planet gear carrier <NUM>. As such, torque that is provided by the electric motor module <NUM> may be transmitted through the rotor output flange <NUM>, sun gear <NUM>, planet gears <NUM>, and planet gear carrier <NUM> to the shift collar <NUM> and from the shift collar <NUM> to the drive pinion <NUM>. The torque may be provided at the first gear ratio in the first position.

Referring to <FIG>, the shift collar <NUM> is 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 collar <NUM> may not couple the gear reduction module <NUM> to the drive pinion <NUM>. For example, the teeth of the shift collar gear <NUM> may not mesh with the teeth of the sun gear <NUM> or the planet gear carrier <NUM>. As such, torque that is provided by the electric motor module <NUM> may not be transmitted to the shift collar <NUM> or the drive pinion <NUM>. The shift collar <NUM> may be disposed closer to the axle housing <NUM> when in the second position than when in the first position.

Referring to <FIG>, the shift collar <NUM> is shown in the third position. In the third position, the shift collar <NUM> may couple the sun gear <NUM> to the drive pinion <NUM>. For example, the teeth of the shift collar gear <NUM> may mesh with the teeth of the first gear portion <NUM> of the sun gear <NUM>. As such, torque that is provided by the electric motor module <NUM> may be transmitted through the rotor output flange <NUM> and sun gear <NUM> to the shift collar <NUM> and from shift collar <NUM> to the drive pinion <NUM>. Torque may be provided at a second gear ratio in the third position. The shift collar <NUM> may be disposed closer to the axle housing <NUM> when in the third position than when in the second position.

Referring primarily to <FIG> and <FIG>, the shift collar <NUM> may be at least partially received in the shift mechanism housing <NUM>. For instance, the shift collar <NUM> may be at least partially received in the shift mechanism housing <NUM> and may extend through components of the gear reduction module <NUM>, such as the planet gear carrier <NUM>. In addition, the shift collar <NUM> may be rotatable with the drive pinion <NUM> and may be movable along the first axis <NUM> with respect to the drive pinion <NUM>. In at least one configuration such as is best shown with reference to <FIG> and <FIG>, the shift collar <NUM> may include a first end <NUM>, a second end <NUM>, a shift collar hole <NUM>, a shift collar spline <NUM>, a shift collar groove <NUM>, a shift collar gear <NUM>, and a set of detection features <NUM>.

The first end <NUM> may face toward the differential carrier <NUM>. In addition, the first end <NUM> may be disposed adjacent to the drive pinion <NUM>.

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

The shift collar hole <NUM> may be a through hole that may extend through the shift collar <NUM>. For instance, the shift collar hole <NUM> may extend from the first end <NUM> to the second end <NUM>. The shift collar hole <NUM> may extend around and along the first axis <NUM>. The shift collar hole <NUM> may receive the shaft portion <NUM> of the drive pinion <NUM>.

Referring to <FIG> and <FIG>, the shift collar spline <NUM> may be disposed in the shift collar hole <NUM>. The shift collar spline <NUM> may be axially positioned near the first end <NUM>. The shift collar spline <NUM> may extend toward the first axis <NUM> and may mate with the spline <NUM> of the drive pinion <NUM>. The mating splines may allow the shift collar <NUM> to move in an axial direction or along the first axis <NUM> while inhibiting rotation of the shift collar <NUM> about the first axis <NUM> with respect to the drive pinion <NUM>. Thus, the shift collar <NUM> may be rotatable about the first axis <NUM> with the drive pinion <NUM> when the shift collar spline <NUM> mates with the spline <NUM>.

The shift collar groove <NUM> may be disposed proximate a second end of the shift collar <NUM> that may face toward the end plate <NUM> or may be disposed proximate the set of detection features <NUM>. The shift collar groove <NUM> may face away from the first axis <NUM> and may extend around the first axis <NUM>. The shift collar groove <NUM> may receive a linkage <NUM>, such as the shift fork, that may operatively connect the shift collar <NUM> to the actuator <NUM>.

The shift collar gear <NUM> may be disposed between the first end and the second end of the shift collar <NUM>. The shift collar gear <NUM> may be disposed opposite the shift collar hole <NUM>. The shift collar gear <NUM> may have teeth that may be arranged around the first axis <NUM> and that may extend away from the first axis <NUM>. An annular groove <NUM> may optionally be provided in the shift collar gear <NUM>. The annular groove <NUM> may extend partially or completely around the first axis <NUM>. As is best shown in <FIG> and <FIG>, the annular groove <NUM> may receive a stop <NUM> that may limit axial movement of the shift collar <NUM>. The stop <NUM> may have any suitable configuration. For instance, the stop <NUM> may be configured as a protrusion. As an example, the stop <NUM> may include one or more snap rings.

Referring to <FIG>, the set of detection features <NUM> may be arranged around the first axis <NUM>. Each detection feature <NUM> may protrude away from the first axis <NUM> such that a recess or gap <NUM> may be provided between adjacent detection features <NUM>. In at least one configuration, the detection features <NUM> may have common configurations and may be arranged in a repeating pattern. The detection features <NUM> may be located in any suitable location where they may be detected with a sensor <NUM>. For instance, the detection features <NUM> may be located outside of components of the gear reduction module <NUM>, such as outside of the sun gear <NUM>, the planet gear carrier <NUM>, or both. As an example, the set of detection features <NUM> may be disposed adjacent to the second end <NUM> of the shift collar <NUM>. In at least one configuration, the set of detection features <NUM> may be disposed between the second end <NUM> and the shift collar groove <NUM>. For example, the detection features <NUM> may extend between the second end <NUM> and the shift collar groove <NUM>, may extend from the second end <NUM> to or toward the shift collar groove <NUM>, or may extend from the shift collar groove <NUM> to or toward the second end <NUM>.

As an overview, the detection features <NUM> may be configured to allow the sensor <NUM> detect the presence or absence of a detection feature <NUM> and generate a signal in response. For instance, the signal generated by the sensor <NUM> may vary as the shift collar <NUM> rotates about the first axis <NUM>. The sensor <NUM> may provide a signal that is "off' (e.g., zero voltage) when a detection feature <NUM> is not detected and may provide a signal that is "on" (e.g., a positive voltage such as 5V) when a detection feature <NUM> is detected. As such, the signal may manifest as a sequence of pulses between "off' and "on" when the shift collar <NUM> rotates about the first axis <NUM>. The signal and its pulses may be processed, such as with the controller <NUM>, to provide a duty cycle. The duty cycle may be a ratio of time that the signal is "on" compared to the time that the signal is "off' (e.g., the duty cycle may be a ratio between the duration of a pulse or pulse width and the period). Duty cycle may be expressed as a percentage and may describe the percentage of time that a signal is "on" over an interval or period of time. As will be discussed in more detail below, different duty cycles may be associated with two or more positions in which the shift collar <NUM> may be positioned along the first axis <NUM>. The different duty cycles may be provided by configuring the detection features <NUM> such that the width of a detection feature <NUM> changes in an axial direction or in a direction that extends along the first axis <NUM>. By using a duty cycle, the axial position of the shift collar <NUM> may be ascertained over a range of rotational speeds of the shift collar <NUM> or independent of the rotational speed of the shift collar <NUM>. Accordingly, the sensor <NUM> may detect rotation or the rotational speed of the shift collar <NUM> based on the rate at which the detection features <NUM> rotate about the first axis <NUM>, may detect the axial position of the shift collar <NUM> along the first axis <NUM> based on the duty cycle, or both.

By detecting the axial position of the shift collar <NUM>, the sensor <NUM> may provide redundant functionality with respect to the actuator sensor <NUM>. In other words, the actuator sensor <NUM> and the sensor <NUM> may both be capable of detecting the axial position of the shift collar <NUM>, and hence whether the gear reduction module <NUM> is in a neutral position or whether a gear ratio is engaged. Accordingly, the sensor <NUM> may provide backup functionality in addition to the actuator sensor <NUM>, verification functionality in that signals from the actuator sensor <NUM> and the sensor <NUM> may be compared by the controller <NUM> to verify a shift position, or diagnostic capabilities that may assess whether a sensor is operating properly. Moreover, the sensor <NUM> may directly detect the position of the shift collar <NUM> as opposed to the actuator sensor <NUM> that may detect the angular position of the output shaft of the actuator <NUM>. As such, the actuator sensor <NUM> may indirectly detect the position of the shift collar <NUM> and may not be capable of detecting improper operation of intervening components, such as the cam <NUM> or linkage <NUM>. The sensor <NUM> may also detect rotational speed in axial position of the shift collar <NUM> as will be discussed in more detail below, which may eliminate the need to provide separate sensors to detect rotational speed and axial position, which may help reduce weight, package space or length of the axle assembly, and associated costs.

Various configurations of detection features and associated duty cycles will now be described. Examples of detection features <NUM> are illustrated in the <FIG> that end with the letter A (i.e., <FIG>, <FIG>). Associated pulses that may be detected by the sensor <NUM> are illustrated in the corresponding figures that end with the letter B (i.e., <FIG>, <FIG>).

In the "A" figures, an approximation of a top view of a pair of detection features <NUM> is shown (noting that additional detection features may be provided and arranged around the first axis <NUM>). In the "A" figures, the horizontal dotted line designated P1 may represent the axial location along the detection features <NUM> that may be detected by the sensor <NUM> when the shift collar <NUM> is in a first position along the first axis <NUM>. The horizontal short dash line designated P2 may represent the axial location along the detection features <NUM> that may be detected by the sensor <NUM> when the shift collar <NUM> is in a second position along the first axis <NUM>. The horizontal long dash line designated P3 may represent the axial location along the detection features <NUM> that may be detected by the sensor <NUM> when the shift collar <NUM> is in a third position along the first axis <NUM>.

In the "B" figures, the pulses associated with the first, second, and third positions are shown. Each plot is aligned below its corresponding "A" figure. The vertical axis may designate the "off' position with a zero and the "on" position with a <NUM>. The horizontal axis may represent time. The dotted, short dash, and long dash lines in the "B" figures correspond with the line types used in the "A" figures. It is noted that the lines overlap in the "on" position and thus generally appear as a solid line.

In <FIG>, each detection feature <NUM> may have a first flank <NUM> and a second flank <NUM> that is disposed opposite the first flank <NUM>. In these figures, the first flank <NUM> may become progressively closer to the second flank <NUM> in a direction that extends from the bottom of the figure toward the top of the figure. This direction may be referred to as a first direction and may represent a direction along the first axis <NUM>. For instance, the first direction may extend along the first axis <NUM> in a direction that extends from the second end <NUM> of the shift collar <NUM> toward the first end <NUM> of the shift collar <NUM>. It is also contemplated that the first direction or orientation of the detection features <NUM> may be reversed, in which case the first direction may extend along the first axis <NUM> from the first end <NUM> toward the second end <NUM>. The first flank <NUM> and the second flank <NUM> may be substantially planar in one or more configurations, such as the configurations shown in <FIG>.

Referring to <FIG>, detection features <NUM> are shown with a first flank <NUM> and a second flank <NUM> that are tapered and become progressively closer together in the first direction. For instance, the first flank <NUM> and the second flank <NUM> may become progressively closer as the distance from the second end <NUM> increases. The first flank <NUM> may be disposed in a first plane that may be disposed in a nonparallel relationship with the first axis <NUM>. The second flank <NUM> may be disposed in a second plane that may be disposed in a nonparallel relationship with the first axis <NUM>. The first flank <NUM> and the second flank <NUM> may be disposed in a nonparallel relationship such that the first plane may intersect the second plane is represented by the intersecting plane lines extending above the flanks from the perspective shown. As such, the width or distance from the first flank <NUM> to the second flank <NUM> along line P1 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P2. Similarly, the width or distance from the first flank <NUM> to the second flank <NUM> along line P2 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P3.

Referring to <FIG>, a corresponding signal plot is shown. The signal may include pulses that may be proportional to the width of the detection feature <NUM>. The pulse width associated with the first position (P1) is greater than the pulse width associated with the second position (P2). The pulse width associated with the second position (P2) is greater than the pulse width associated with the third position (P3). The signal and its pulses may be processed to provide a duty cycle as previously discussed. Accordingly, the duty cycle associated with the first position may differ from the duty cycle associated with the second position and the duty cycle associated with the third position may differ from the duty cycle associated with the first and second positions. In the configuration illustrated, the duty cycle associated with the first position may be greater than the duty cycle associated with the first and second positions and the duty cycle associated with the second position may be greater than the duty cycle associated with the third position. As a nonlimiting example, the duty cycle in the first position may be approximately <NUM>%, the duty cycle and the second position may be approximately <NUM>%, and the duty cycle in the third position may be approximately <NUM>%. The duty cycle may be compared to a predetermined value or predetermined duty cycle range that may be stored in memory and may be accessed by the controller <NUM>. For instance, duty cycle ranges corresponding with the first, second, and third positions may be stored in memory, such as in a lookup table, and the controller <NUM> may determine what position the shift collar <NUM> is located in by comparing the current duty cycle with the duty cycle ranges to determine which duty cycle range corresponds with the current duty cycle.

Referring to <FIG>, detection features <NUM> are shown with a first flank <NUM> and a second flank <NUM> that are tapered and become progressively closer together in the first direction. The first flank <NUM> may be disposed in a first plane that may be disposed in a non-parallel relationship with the first axis <NUM>. The second flank <NUM> may be disposed in a second plane that may be disposed in a parallel relationship with the first axis <NUM> or a substantially parallel relationship (within ±<NUM>°) with the first axis <NUM>. The width or distance from the first flank <NUM> to the second flank <NUM> along line P1 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P2. Similarly, the width or distance from the first flank <NUM> to the second flank <NUM> along line P2 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P3.

Referring to <FIG>, a corresponding signal plot is shown. The pulse width associated with the first position (P1) is greater than the pulse width associated with the second position (P2). The pulse width associated with the second position (P2) is greater than the pulse width associated with the third position (P3). The signal and its pulses may be processed to provide a duty cycle as previously described. The duty cycle associated with the first position may be greater than the duty cycle associated with the second position and the duty cycle associated with the second position may be greater than the duty cycle associated with the third position. The controller <NUM> may determine what position the shift collar <NUM> is located in by comparing the current duty cycle with the duty cycle ranges to determine which range corresponds with the current duty cycle as previously discussed.

Referring to <FIG>, the first flank <NUM> and the second flank <NUM> are configured in a relationship opposite that shown in <FIG>. The detection features <NUM> are shown with a first flank <NUM> and a second flank <NUM> that are tapered and become progressively closer together in the first direction, however, the first flank <NUM> may be disposed in a parallel or substantially parallel relationship with the first axis <NUM> while the second flank <NUM> may be disposed in a non-parallel relationship with the first axis <NUM>. The width or distance from the first flank <NUM> to the second flank <NUM> along line P1 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P2. Similarly, the width or distance from the first flank <NUM> to the second flank <NUM> along line P2 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P3.

Referring to <FIG>, a corresponding signal plot is shown. The pulse widths maybe the same as those in <FIG> but may be offset along the horizontal axis as compared to <FIG>.

Referring to <FIG>, detection features <NUM> are shown in which the first flank <NUM> and the second flank <NUM> may become progressively closer together but may be nonlinear or nonplanar. For instance, the first flank <NUM> and the second flank <NUM> may each extend along an arc or a curve between its opposing ends. In the configuration shown, the first flank <NUM> and the second flank <NUM> are illustrated as being concave; however, it is contemplated that the first flank <NUM>, the second flank <NUM>, or both may be convex. The width or distance from the first flank <NUM> to the second flank <NUM> along line P1 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P2. Similarly, the width or distance from the first flank <NUM> to the second flank <NUM> along line P2 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> along line P3.

Referring to <FIG>, a corresponding signal plot is shown. The pulse width associated with the first position (P1) is greater than the pulse width associated with the second position (P2). The pulse width associated with the second position (P2) is greater than the pulse width associated with the third position (P3). The duty cycle associated with the first position may be greater than the duty cycle associated with the second position and the duty cycle associated with the second position may be greater than the duty cycle associated with the third position. The controller <NUM> may determine what position the shift collar <NUM> is located in by comparing the current duty cycle with the duty cycle ranges to determine which range corresponds with the current duty cycle as previously discussed.

Referring to <FIG>, detection features <NUM> are shown with a configuration in at least which one flank may have a stepped profile. The profile may be stepped relative to a center plane <NUM> of the detection feature <NUM>. The center plane <NUM> may be disposed parallel to the first axis <NUM>. For instance, the first axis <NUM> may be completely disposed in the center plane <NUM> and one or more configurations. The center plane <NUM> may bisect the detection feature <NUM> in configurations where the detection feature <NUM> is symmetrical or in which the first flank <NUM> and the second flank <NUM> have mirror symmetry with respect to the center plane <NUM>. The center plane <NUM> may not bisect the detection feature <NUM> in configurations that do not have mirror symmetry. However, the center plane <NUM> may still be disposed between the first flank <NUM> and the second flank <NUM>. The center plane <NUM> may be spaced apart from the first flank <NUM> and the second flank <NUM>.

Referring to <FIG>, the first flank <NUM>, the second flank <NUM>, or both, may have a plurality of flank segments, such as a first flank segment <NUM>, a second flank segment <NUM>, and a third flank segment <NUM>. The first flank segment <NUM>, the second flank segment <NUM>, and the third flank segment <NUM> may be disposed in a parallel or nonparallel relationship. In the configuration shown, a parallel relationship is depicted in which the second flank segment <NUM> is disposed closer to the center plane <NUM> than the first flank segment <NUM> and the third flank segment <NUM> is disclosed closer to the center plane <NUM> and the second flank segment <NUM>. As such, the sensor <NUM> may detect the first flank segment <NUM> along line P1, the second flank segment <NUM> along line P2, and the third flank segment <NUM> along line P3. The width or distance from the first flank <NUM> to the second flank <NUM> (or between opposing first flank segments <NUM> in the configuration shown) along line P1 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> (or between opposing second flank segments <NUM>) along line P2. Similarly, the width or distance from the first flank <NUM> to the second flank <NUM> along line P2 may be greater than the width or distance from the first flank <NUM> to the second flank <NUM> (or between opposing third flank segments <NUM>) along line P3.

Referring to <FIG>, another stepped flank configuration is shown. In this configuration, the first flank segment <NUM> and the third flank segment <NUM> may have the same configuration or may be disposed at the same distance from the center plane <NUM> while the second flank segment <NUM> is disposed at a different distance from the center plane <NUM>. It is contemplated that the second flank segment <NUM> may be disposed further from the center plane <NUM> than the first flank segment <NUM> and the third flank segment <NUM> as shown or that the second flank segment <NUM> may be disposed closer to the center plane <NUM> than the first flank segment <NUM> and the third flank segment <NUM>.

Referring to <FIG>, a corresponding signal plot is shown. The pulse width associated with the first position (P1) and the third position (P3) may differ from the pulse width associated with the second position (P2). As such, the duty cycle associated with the second position (P2) may differ from the duty cycle associated with the first position (P1) and the third position (P3). Moreover, the pulse width and/or duty cycle associated with the first position (P1) may be the same as the pulse width and/or duty cycle associated with the third position (P3). As such, the signal from the sensor <NUM> may be used to distinguish the second position (P2) from the first position (P1) and the third position (P2) but may not be used to distinguish the first position (P1) from the third position ((P3). The controller <NUM> may determine what position the shift collar <NUM> is located in by comparing the current duty cycle with the duty cycle ranges to determine which range corresponds with the current duty cycle as previously discussed. For instance, the duty cycle ranges associated with the first and third positions may be the same while the duty cycle arranged associated with the second position may differ from the duty cycle ranges associated with the first and third positions.

Referring to <FIG>, a configuration is shown in which the shift collar <NUM> has detection features <NUM> that are provided with a plurality of toothed rings. One or more toothed rings may be provided. In the configuration shown, the shift collar <NUM> has a first toothed ring <NUM>, a second toothed ring <NUM>, and a third toothed ring <NUM>. The first toothed ring <NUM>, the second toothed ring <NUM>, and the third toothed ring <NUM> may be positioned along the first axis <NUM>. The first toothed ring <NUM>, the second toothed ring <NUM>, and the third toothed ring <NUM> may be axially spaced apart from each other or may be separated with spacers <NUM> that may be disposed closer to the first axis <NUM> than the teeth of the toothed rings and optionally closer to the first axis <NUM> than the bottom of the gaps <NUM> between the teeth of the toothed rings. The detection features <NUM> and toothed rings may be located in any suitable location where they may be detected with the sensor <NUM>, such as adjacent to the second end <NUM> of the shift collar <NUM> or between the second end <NUM> and the shift collar groove <NUM> as previously discussed.

Referring to <FIG>, a side view of examples of the toothed rings are shown. The toothed rings may be centered about the first axis <NUM>. Each toothed ring may have detection features <NUM> that may be configured as teeth that may that protrude away from the first axis <NUM>. Individual teeth that are provided with the first toothed ring <NUM>, the second toothed ring <NUM>, and the third toothed ring <NUM> may have the same configurations. For instance, the teeth may have the same size, shape, and may protrude by the same distance from the first axis <NUM>. Moreover, the teeth may be arranged such that adjacent teeth may be equidistantly spaced from each other. However, each toothed ring may have a different number of teeth. In the example shown, the first toothed ring <NUM> is missing one tooth, the second toothed ring <NUM> is missing two teeth, and the third toothed ring <NUM> is missing three teeth. Any suitable configuration may be provided in which each toothed ring has a different number of teeth. For instance, one toothed ring may be provided without any missing teeth or all toothed rings may be provided with multiple missing teeth. Missing teeth locations may be located adjacent to each other or may be spaced apart from each other. The teeth of each toothed ring may or may not be axially aligned with each other. The sensor <NUM> may detect the first toothed ring <NUM> when the shift collar <NUM> is in the first position, may detect the second toothed ring <NUM> when the shift collar <NUM> is in the second position, and may detect the third toothed ring <NUM> when the shift collar <NUM> is in the third position.

Referring to <FIG>, a corresponding signal plot is shown. In this signal plot, the darkened squares may represent detection of a tooth or a pulse that may be associated with detection of a tooth while the non-darkened squares may represent gaps between teeth. Accordingly, a signal may include pulses that may be a function of the number of teeth of a detected toothed ring. Thus, different axial positions of the shift collar <NUM> may be based on the change in frequency at which teeth are detected. The number of teeth that may be detected by the sensor <NUM> over one revolution of the shift collar <NUM> at the first position (P1) may differ from the number of teeth detected over one revolution at the second position (P2). The number of teeth that may be detected over one revolution at the third position (P3) may differ from the number of teeth detected over one revolution at the first position (P1), the second position (P2), or both.

The detected tooth count or frequency may be compared to predetermined tooth counts or frequencies that may be stored in memory and may be accessed by the controller <NUM>. For instance, tooth counts or frequencies corresponding with the first, second, and third positions may be stored in memory, such as in a lookup table, and the controller <NUM> may determine what position the shift collar <NUM> is located in by comparing the current tooth count or frequency with the tooth counts or frequencies in memory to determine which position with the current signal. In the example shown, a signal with a pulse pattern that has <NUM> pulses per revolution may correspond to the first position (P1), a pulse pattern that has <NUM> pulses per revolution may correspond to the second position (P2), and a pulse pattern that has <NUM> pulses per revolution may correspond to the third position (P3). The rate at which teeth may be detected may be indicative of the rotational speed of the shift collar <NUM>. As such, the sensor <NUM> may detect the teeth of a toothed ring that is aligned with the sensor <NUM> and may provide a signal that may be indicative of rotation of the shift collar <NUM>, positioning of the shift collar <NUM> along the first axis <NUM>, or both. For instance, the sensor <NUM> may detect rotation or the rotational speed of the shift collar <NUM> based on the rate at which the teeth rotate about the first axis <NUM>, may detect the axial position of the shift collar <NUM> along the first axis <NUM> based on the pulse pattern or number of pulses detected per revolution, or both.

The controller <NUM> may control operation of the axle assembly <NUM>. The controller <NUM> may receive signals from various sensors, such as the first sensor <NUM> and the sensor <NUM>. In addition, the controller <NUM> may control the actuator <NUM> and thereby control movement of the shift collar <NUM>.

The first sensor <NUM> may provide a first signal that may be indicative of a rotational speed of the gear reduction module <NUM> or a component thereof like the planet gear carrier <NUM>. The sensor <NUM> may provide a second signal that may be indicative of a rotational speed of the drive pinion <NUM>.

The controller <NUM> may use the first signal and the second signal to determine when a shift of the shift collar <NUM> may be executed. For instance, the controller <NUM> may use the first signal and the second signal to determine when the rotational speed of the shift collar <NUM> is sufficiently close to the rotational speed of a component of the planetary gear set <NUM>, such as the sun gear <NUM> and/or the planet gear carrier <NUM> to permit the shift collar <NUM> to be shifted to or from the neutral position. The controller <NUM> operate the actuator <NUM> to move the shift collar <NUM> to a desired position when shifting of the shift collar <NUM> may be executed and completed.

As an example that starts with the shift collar <NUM> and the first position or the third position, the controller <NUM> may determine when the first and second signals are indicative of sufficiently close rotational speeds. The controller <NUM> may then temporarily relieve or reduced torque on the shift collar <NUM> by controlling the rotational speed of the rotor <NUM> or reducing power provided from an electrical power source / inverter to permit the shift collar <NUM> to be more easily be actuated from the first position or the third position to the second (neutral) position. The controller <NUM> may then operate the actuator <NUM> to move the shift collar <NUM> to the second position.

The controller <NUM> may move the shift collar <NUM> from the second position to either the first position or the third position by controlling the rotational speed of the rotor <NUM> to synchronize the rotational speed of the shift collar <NUM> with the sun gear <NUM> to allow the shift collar <NUM> to move to the second position to the first position or may synchronize the rotational speed of the shift collar <NUM> with the planet gear carrier <NUM> to allow the shift collar <NUM> to move from the neutral position to the third position.

Claim 1:
An axle assembly (<NUM>) comprising:
an electric motor module (<NUM>);
a gear reduction module (<NUM>) that is operatively connected to the electric motor module (<NUM>);
a drive pinion (<NUM>) that is rotatable about a first axis (<NUM>);
a shift collar (<NUM>) that is rotatable with the drive pinion (<NUM>) and moveable along the first axis (<NUM>) such that the shift collar (<NUM>) is selectively couplable to the gear reduction module (<NUM>), characterized in that the shift collar (<NUM>) has a set of detection features (<NUM>) that are arranged around the first axis (<NUM>) such that a gap (<NUM>) is provided between adjacent detection features (<NUM>); and in that the axle assembly further comprises
a sensor (<NUM>) that is configured to detect the set of detection features (<NUM>) and provide a signal indicative of rotation of the shift collar (<NUM>) about the first axis (<NUM>), wherein a duty cycle of the signal varies as the shift collar (<NUM>) moves along the first axis (<NUM>) and is indicative of positioning of the shift collar (<NUM>) along the first axis (<NUM>).