Multi-speed electric drive axle using multi-layshaft transmission

An electric drive axle with an electric motor having a motor shaft that is rotatable about an axis, a differential, and a transmission. The transmission transmits rotary power between the motor shaft and the differential. The multi-speed reduction has an input shaft and at least three on-axis gears. The input shaft is rotatably coupled to the motor shaft. Each of the at least three on-axis gears is co-axial with the input shaft and is rotatable relative to the input shaft in at least one of a first speed ratio and a second speed ratio. The input shaft is axially movable along the axis between a first position, in which a first one of the at least three on-axis gears is rotationally coupled to the input shaft, and a second position in which a second one of the at least three on-axis gears is rotationally coupled to the input shaft.

FIELD

The present disclosure relates to a multi-speed electric drive axle that uses a multi-layshaft transmission.

BACKGROUND

Electric drive axles are becoming increasingly popular in the drivelines of automotive vehicles. There is increasing interest in electric drive axles that employ multi-speed transmissions. One drawback to the such electric drive axles is that heretofore the multi-speed transmission can be difficult to package into a vehicle in such a way that does not impact either cabin space or vehicle clearance. Accordingly, there is a need in the art for an improved electric drive axle having a multi-speed transmission that is relatively compact.

SUMMARY

In one form, the present disclosure provides an electric drive axle that includes a housing assembly, an electric motor, a differential assembly, and a transmission. The electric motor is coupled to the housing assembly and has a motor shaft that is rotatable about a motor axis. The differential assembly is received in the housing assembly and includes a differential input member, which is rotatable about an output axis, and a pair of differential output members that are rotatable about the output axis. The transmission is received in the housing assembly and transmits rotary power between the motor shaft and the differential input member. The transmission has an input shaft, which is rotatably coupled to the motor shaft and axially movable along the motor axis, a first reduction gearset, a second reduction gearset, and a coupling sleeve. The first reduction gearset has a first intermediate input gear and a first intermediate output gear. The first intermediate output gear is axially slidably and rotatably disposed on the input shaft. The first intermediate output gear is meshingly engaged with the first intermediate input gear and is rotatable about an intermediate axis that is parallel to the motor axis. The second reduction gearset has a second intermediate input gear, a second intermediate output gear, a first intermediate gear, a second intermediate gear, a third intermediate gear and a fourth intermediate gear. The input shaft is rotatable and axially slidable relative to the second intermediate input gear, the third intermediate gear and the fourth intermediate gear. The first intermediate gear is meshingly engaged to the second intermediate input gear. The second intermediate gear is coupled to the first intermediate gear for rotation therewith and is meshingly engaged to the third intermediate gear. The fourth intermediate gear is meshingly engaged to the second intermediate output gear. The coupling sleeve is rotatable about the input shaft but is coupled to the input shaft for translation therewith along the motor axis. The input shaft is movable between a first position, in which the input shaft is rotatably coupled to the first intermediate input gear and the coupling sleeve is rotationally decoupled from at least one of the third intermediate gear and the fourth intermediate gear, and a second position in which the input shaft is rotationally decoupled from the first intermediate input gear, the input shaft is rotationally coupled to the second intermediate input gear, and the coupling sleeve rotationally couples the third and fourth intermediate gears to one another.

In another form, the present disclosure provides an electric drive axle that includes a housing assembly, an electric motor, a differential assembly, and a transmission. The electric motor is coupled to the housing assembly and has a motor shaft that is rotatable about a motor axis. The differential assembly is received in the housing assembly and includes a differential input member, which is rotatable about an output axis, and a pair of differential output members that are rotatable about the output axis. The transmission is received in the housing assembly and transmits rotary power between the motor shaft and the differential input member. The transmission has a multi-speed reduction that includes an input shaft, which is rotatably coupled to the motor shaft and axially movable along the motor axis, a first reduction gearset, a second reduction gearset, and a coupling sleeve. The first reduction gearset has a first intermediate input gear and a first intermediate output gear. The first intermediate output gear is axially slidably and rotatably disposed on the input shaft. The first intermediate output gear is meshingly engaged with the first intermediate input gear and is rotatable about an intermediate axis that is parallel to the motor axis. The second reduction gearset has a second intermediate input gear, a second intermediate output gear, a first intermediate gear and a second intermediate gear. The second intermediate input gear is axially slidably and rotationally coupled to the input shaft. The first intermediate gear is axially slidably and rotatably disposed on the input shaft. The second intermediate gear is axially slidably and rotatably disposed on the input shaft. The second intermediate output gear is meshingly engaged with the second intermediate gear and is coupled to the first intermediate output gear for common rotation about the intermediate axis. The coupling sleeve is rotatably received on but axially fixed to the input shaft. The input shaft is movable between a first position, in which the input shaft is rotatably coupled to the first intermediate input gear and the coupling sleeve is rotationally decoupled from at least one of the first intermediate gear and the second intermediate gear, and a second position in which the input shaft is rotationally decoupled from the first intermediate input gear and the coupling sleeve rotationally couples the first and second intermediate gears to one another.

In still another form, the present disclosure provides an electric drive axle that includes a housing assembly, an electric motor, a differential assembly, and a transmission. The electric motor coupled to the housing assembly and has a motor shaft that is rotatable about a motor axis. The differential assembly is received in the housing assembly and includes a differential input member, which is rotatable about an output axis, and a pair of differential output members that are rotatable about the output axis. The transmission is received in the housing assembly and transmits rotary power between the motor shaft and the differential input member. The transmission has a multi-speed reduction that is selectively operable in a first speed ratio and a second speed ratio. The multi-speed reduction has an input shaft and at least three on-axis gears. The input shaft is rotatably coupled to the motor shaft. Each of the at least three on-axis gears is co-axial with the input shaft and is rotatable relative to the input shaft in at least one of the first and second speed ratios. The input shaft is axially movable along the motor axis between a first position, in which a first one of the at least three on-axis gears is rotationally coupled to the input shaft, and a second position in which a second one of the at least three on-axis gears is rotationally coupled to the input shaft.

In yet another form, the present disclosure provides an electric drive axle that includes a housing assembly, an electric motor, a differential assembly, a mounting plate, a transmission, a first bearing and a second bearing. The housing assembly has a housing member that defines a first bearing mount. The electric motor coupled to the housing assembly and has a motor shaft that is rotatable about a motor axis. The differential assembly is received in the housing assembly and includes a differential input member, which is rotatable about an output axis, and a pair of differential output members that are rotatable about the output axis. The mounting plate is coupled to the housing assembly and defines a second bearing mount. The transmission is received in the housing assembly and transmits rotary power between the motor shaft and the differential input member. The transmission has a compound gear that includes a layshaft, a first intermediate gear and a second intermediate gear that are coupled to one another for common rotation about an intermediate axis. The first bearing received in the first bearing mount and supports a first end of the layshaft for rotation about the intermediate axis relative to the housing member. The second bearing is mounted in the second bearing mount and supports a second end of the layshaft for rotation about the intermediate axis relative to the mounting plate. A lubrication gallery is formed in the mounting plate. The lubrication gallery is in fluid communication with the first and second bearing mounts.

In still another form, the present disclosure provides an electric drive axle that includes a housing assembly, a transmission, and a park-lock mechanism. The housing assembly has first and second housing members that cooperate to define a transmission cavity therebetween. The second housing member defines a second mount and a pivot pin aperture. The transmission is received in the transmission cavity. The transmission has a gear that is supported by a bearing that is received in the bearing mount. The park-lock mechanism includes a park-lock gear, which is coupled for rotation with an element of the transmission, a pivot pin, a park pawl, a spring, and a park-lock plunger assembly. The pivot pin is received in the pivot pin aperture and is rotatable relative to the second housing member about a pivot axis. The park pawl is coupled to the pivot pin for common rotation the pivot axis between an engaged position, in which the park pawl is engaged to the park-lock gear, and a disengaged position in which the park pawl is disengaged from the park-lock gear. The spring biases the park pawl out of engagement with the park-lock gear. The park-lock plunger assembly has an input member, a plunger, and a compliance spring. The input member is disposed along an actuation axis. The plunger is slidably disposed on the input member and is movable along the actuation axis between a first position and a second position. The actuation axis is parallel to the pivot axis. Movement of the plunger from the first position toward the second position causes corresponding motion of the park pawl toward the engaged position. Placement of the plunger in the second position permits the spring to move the park pawl into the disengaged position. The compliance spring is disposed coaxially on the input member and biases a head of the input member apart from the plunger.

In yet another form, the present disclosure provides a method for assembling an electric drive axle. The method includes: providing a first housing member; assembling a transmission into the first housing member, the transmission including a gear supported on a bearing; providing a second housing member, the second housing member defining a bearing mount; installing a park-lock mechanism to the second housing member, the park-lock mechanism has a park-lock gear, a pivot pin, a park pawl, a spring, and a park-lock plunger assembly, the park-lock gear is coupled for rotation with an element of the transmission, the pivot pin is received in the pivot pin aperture and is rotatable relative to the second housing member about a pivot axis, the park pawl is coupled to the pivot pin for common rotation the pivot axis between an engaged position, in which the park pawl is engaged to the park-lock gear, and a disengaged position in which the park pawl is disengaged from the park-lock gear, the spring biasing the park pawl out of engagement with the park-lock gear, the park-lock plunger assembly has an input member, a plunger, and a compliance spring, the input member is disposed along an actuation axis, the plunger is slidably disposed on the input member and movable along the actuation axis between a first position and a second position, the actuation axis is parallel to the pivot axis the plunger, wherein movement of the plunger from the first position toward the second position causes corresponding motion of the park pawl toward the engaged position, and wherein placement of the plunger in the second position permits the spring to move the park pawl into the disengaged position, the compliance spring disposed coaxially on the input member and biasing a head of the input member apart from the plunger; and assembling the second housing member to the first housing member to install the bearing into the bearing mount and to enclose the transmission, the park-lock gear, the pivot pin, the park pawl and the plunger assembly within a housing assembly that is formed by the first and second housing members.

In a further form, the present disclosure provides a vehicle driveline component that includes a housing assembly, a multi-speed reduction, which is received in the housing assembly, and an actuator assembly. The multi-speed reduction has a movable element that is movable along a shift axis between a first position and a second position. Placement of the movable element in the first position causes the multi-speed reduction to operate in a first speed reduction ratio, while placement of the movable element in the second position causes the multi-speed reduction to operate in a second speed reduction ratio that is different from the first speed reduction ratio. The actuator assembly has an actuator motor, a screw, an actuator output member, a coupler and at least one coupler pad. The screw is driven by the actuator motor about a screw axis that is parallel to the shift axis. The actuator output member has a first end and a second end that is opposite the first end. The movable element of the multi-speed reduction is axially fixed but rotatable relative to the first end of the axially movable member. The second end of the axially movable member defines a pocket. The coupler is threadably coupled to the screw and is received into the pocket. Each of the at least one coupler pads is received in the pocket and is mounted to one of the coupler and the axially movable member. Each of the at least one coupler pads has a first surface, which abuts an associated surface of the axially movable member, and a second surface that abuts an associated surface of the coupler. The second surface of each of the at least one coupler pads is curved so that contact between the coupler and each of the at least one coupler pads occurs over an associated line that extends in a plane that includes the screw axis.

DETAILED DESCRIPTION

With reference toFIGS.1and2, an exemplary electric drive axle constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral10. The multi-speed electric drive axle10includes several major assemblies or components including a housing assembly12, an electric motor14, a transmission16, a differential assembly18and a pair of axle shafts20.

With specific reference toFIGS.2and3, the housing assembly12of the example provided includes first and second housing members30and32, respectively, and a pair of axle tubes34in which the axle shafts20are rotatably disposed. The housing assembly12is configured to handle beaming loads, and as such, provides the multi-speed electric drive axle10with a “beam” or “rigid” axle configuration. It will be appreciated, however, that the housing assembly12could be configured differently, for example to configure the multi-speed electric drive axle10for use with an independent suspension.

The first and second housing members30and32have a “clam shell” configuration and cooperate to form a carrier housing that defines a gearcase that has a transmission cavity38and a differential cavity40that intersects the differential cavity40. Each of the first and second housing members30and32can define a coupling flange44, a differential bearing mount46, and an axle tube mount48. The first housing member30can additionally include a motor mount50. The coupling flanges44can be abutted against one another and threaded fasteners can be employed to secure the coupling flanges44to one another. A gasket or sealant (not shown) can be disposed between the first and second housing members30and32(e.g., contacting the adjacent faces of the coupling flanges44) so that the first and second housing members30and32are additionally sealingly coupled to one another. Each differential bearing mount46is formed into an in-board side of an associated one of the first and second housing members30and32and is configured to receive a differential bearing54therein that supports the differential assembly18for rotation about an output axis58. Each axle tube mount48defines an axle tube aperture that is configured to receive therein an associated one of the axle tubes34.

Each of the axle tubes34can be received into an associated one of the axle tube apertures and can be fixedly coupled to an associated one of the axle tube mounts48in any desired manner. In the example shown, the axle tubes34are press-fit into the axle tube apertures and conventional weld slugs (not specifically shown) are employed to inhibit both axial and rotational movement of the axle tubes34along or about the output axis58relative to the first and second housing members30and32.

With reference toFIG.4, the electric motor14can be configured as any type of electric motor and includes a motor housing64, a stator66, which is received into and fixedly coupled to the motor housing64, a rotor68, which is received in the stator66and rotatable relative to the stator66about a motor axis70, and a motor output shaft72that is fixedly coupled to the rotor68. The motor housing64can define a motor bearing mount (not specifically shown) and a seal mount. The motor output shaft72can extend along the motor axis70through the motor housing64and optionally into the transmission cavity38in the housing assembly12. The motor output shaft72can be hollow and can define a plurality of first internal spline teeth80. A motor bearing82can be received between the motor housing64and the motor output shaft72and can support the motor output shaft72for rotation about the motor axis70relative to the motor housing64. A rotary shaft seal84can be mounted on the seal mount and can form a seal between the motor housing64and the motor output shaft72that inhibits fluid transmission through a motor shaft aperture in the motor housing64between the transmission cavity38and the interior of the motor housing64. Fasteners (not specifically shown) can be employed to fixedly couple the motor housing64to the motor mount50on the first housing member30. Alternatively, the motor housing64could be unitarily and integrally formed with the first housing member30. The motor output shaft72can extend through or be disposed in-line with the motor shaft aperture.

As shown inFIGS.5and6, the transmission16in the example provided is a multi-speed transmission, but it will be understood that the transmission16can be any type of transmission, including a single-speed transmission. The particular transmission16shown includes a mounting plate90, a multi-speed input portion92and a single-speed output portion94. The mounting plate90will be described in more detail below, but it will suffice for now that it is received in the transmission cavity38, that it is fixedly coupled to the first housing member30and that a significant portion of the multi-speed input portion92is disposed between the first housing member30and the mounting plate90.

With reference toFIGS.5and7, the multi-speed input portion92includes a first gear100, a second gear102, a third gear104, a first compound gear106, an input shaft108and a coupling sleeve110. The first gear100can have gear teeth with a helical gear tooth form that is disposed about a first gear hub112. The first gear hub112is hollow and can define a plurality of second internal spline teeth114. A bearing116is mounted between the first housing member30and the first gear hub112and supports the first gear100for rotation about the motor axis70. The second gear102can have gear teeth with a helical gear tooth form that is disposed about a second gear hub122. The second gear hub122is hollow and can define a plurality of third internal spline teeth124. A pair of bearings126are mounted between the mounting plate90and the second gear hub122and support the second gear102both axially along and radially about the motor axis70. The first gear100is disposed along the motor axis70between the motor output shaft72and the second gear102. Optionally, a portion of the first gear hub112can be received concentrically within a portion of the second gear hub122.

The third gear104can have gear teeth with a helical gear tooth form that is disposed about a third gear hub132. The third gear hub132is hollow and can define a plurality of fourth internal spline teeth134and a plurality of first face teeth135that are formed onto or into an axial end face of the third gear hub132that faces or is proximate the second gear102. Bearings136aand136bare employed to rotationally support the third gear104for rotation about the motor axis70. The bearing136ais mounted between the mounting plate90and the third gear hub132proximate the second gear102, while the bearing136bis mounted between the gearcase and the third gear hub132on an axial end of third gear104that is opposite the bearing136a.

With reference toFIGS.5,8and9, the first compound gear106includes a first layshaft140, a first intermediate gear142and a second intermediate gear144. The first layshaft140can be hollow and can be supported on opposite sides by first and second bearings146aand146b, respectively, for rotation about a respective first intermediate axis148that is parallel to but offset from (i.e., not coincident with) the motor axis70. The first bearing146acan be disposed between a first intermediate bearing mount150that is formed by the first housing member30, and a first end of the first layshaft140, while the second bearing148bcan be disposed between a second intermediate bearing mount152, which is formed by the mounting plate90, and a second end of the first layshaft140that is opposite the first end. The first intermediate gear142is fixedly coupled to the first layshaft140for rotation therewith about the first intermediate axis148and includes gear teeth that are meshingly engaged with the gear teeth of the first gear100. The second intermediate gear144is fixedly coupled to the first layshaft140for rotation therewith about the first intermediate axis148and includes gear teeth that are meshingly engaged with the gear teeth of the second gear102. It will be appreciated that the first gear100, the second gear102and the first compound gear106can form a reduction gearset.

With reference toFIGS.7and10, the input shaft108is received concentrically through the first, second and third gear hubs112,122and132and is rotatable about the motor axis70. The input shaft108includes a plurality of first external spline teeth160, which are disposed on a first axial end of the input shaft108that is disposed within the motor output shaft72, a plurality of second external spline teeth162, which are spaced apart from the first external spline teeth160along the motor axis70, and a circumferential rib164that is disposed between the first and second external spline teeth160and162along the motor axis70. A lubrication bore166can be formed through the input shaft108and a plurality of lubrication passages168can be formed through the input shaft108so as to intersect the lubrication bore166and extend radially through the input shaft108at desired locations. A lubrication nozzle can be received into the axial end of the input shaft108that is proximate the third gear104and can be configured to dispense a flow of pressurized lubricating fluid into the lubrication bore166. Pressurized lubricating fluid in the lubrication bore166can be transmitted to the lubrication passages168for cooling and/or lubrication of various components, such as bearings or sliding interfaces, and optionally to communicate pressurized lubricating fluid into the motor output shaft72where it can be employed to cool and/or lubricate various components of the electric motor14. In the example provided, the lubrication nozzle is mounted to an auxiliary cover that is mounted to a side of the second housing member32that is opposite the transmission cavity38and the lubrication nozzle neither contacts nor is sealed to the input shaft108.

Various bearings can be employed to provide radial support to the input shaft108while permitting axial movement of the input shaft108along the motor axis70. In the example provided, a first needle bearing170is disposed between the first gear hub112and a first cylindrical bearing surface formed on the input shaft108, while a second needle bearing172is disposed between the third gear hub132and a second cylindrical bearing surface formed on the input shaft108.

The coupling sleeve110can be received concentrically about the input shaft108and is rotatable about the motor axis70relative to the input shaft108. The coupling sleeve110can define a shoulder that can abut a first side of the circumferential rib164on the input shaft108. An internal snap ring can be received in a groove formed in the coupling sleeve110and can abut a second side of the circumferential rib164on a side opposite the shoulder. As such, translation of the input shaft108along the motor axis70will cause corresponding translation of the coupling sleeve along the motor axis70. The coupling sleeve110defines a plurality of third external spline teeth180and a plurality of second face teeth182. The third external spline teeth180are meshingly engaged with the third internal spline teeth124that are formed on the second gear hub122to thereby couple the coupling sleeve110to the second gear102in a way that inhibit relative rotation but permits axial sliding movement or translation of the coupling sleeve110relative to the second gear102.

The input shaft108is movable along the motor axis70between a high-speed position (shown inFIG.11), a neutral position (shown inFIG.12), and a low-speed position (shown inFIG.13). The first external spline teeth160on the input shaft108are meshingly engaged with the first internal spline teeth80on the motor output shaft72(thereby coupling the input shaft108to the motor output shaft72for rotation therewith about the motor axis70) in each of the high-speed, neutral and low-speed positions.

When the input shaft108is positioned in the high-speed position as shown inFIG.11, the first external spline teeth160on the input shaft108are engaged only to the first internal spline teeth80on the motor output shaft72, the second external spline teeth162on the input shaft108are engaged to the fourth internal spline teeth134formed on the third gear104, and the second face teeth182on the coupling sleeve110are spaced apart and are disengaged from the first face teeth135on the third gear104. Consequently, rotary power output from the electric motor14(FIG.1) through the motor output shaft72is input to the input shaft108and transmitted to the third gear104to drive the third gear104at the rotational speed of the electric motor14(FIG.1).

When the input shaft108is positioned in the neutral position as shown inFIG.12, the first external spline teeth160on the input shaft108are engaged only to the first internal spline teeth80on the motor output shaft72, the second external spline teeth162on the input shaft108are spaced apart and disengaged to the fourth internal spline teeth134formed on the third gear104, and the second face teeth182on the coupling sleeve110are spaced apart and are disengaged from the first face teeth135on the third gear104. Consequently, rotary power output from the electric motor14(FIG.1) through the motor output shaft72is input to the input shaft108but is not transmitted to any of the first, second and third gears100,102and104.

When the input shaft108is positioned in the low-speed position as shown inFIG.13, the first external spline teeth160on the input shaft108are engaged to both the first internal spline teeth80on the motor output shaft72and the second internal spline teeth114on the first gear100, the second external spline teeth162on the input shaft108are spaced apart and disengaged from the fourth internal spline teeth134formed on the third gear104, and the second face teeth182on the coupling sleeve110are engaged with the first face teeth135on the third gear104. Consequently, rotary power output from the electric motor14(FIG.1) through the motor output shaft72is input to the input shaft108and transmitted to the first gear100to drive the first intermediate gear142(FIG.8) to provide a first speed reduction. The second intermediate gear144(FIG.8), which rotates with the first intermediate gear142(FIG.8), drives the second gear102to provide a second speed reduction. As the coupling sleeve110is rotationally coupled with both the second gear102(via the mating engagement of the third external spline teeth180with the third internal spline teeth124) and the third gear104(via mating engagement of the second face teeth182with the first face teeth135), the third gear104rotates at the rotational speed of the second gear102. It will be appreciated that the first gear100, the second gear102and the third gear104are coaxial with the input shaft108and are rotatable relative to the input shaft108in at least one of a first speed ratio and a second speed ratio. Additionally, the input shaft108is axially movable along the motor axis70between a first position, in which a first one of the at least three on-axis gears (i.e., first gear100, second gear102, and third gear104) is rotationally coupled to the input shaft108, and a second position in which a second, different one of the at least three on-axis gears is rotationally coupled to the input shaft.

Returning toFIGS.5and8, the single-speed output portion94receives rotary power from the third gear104and includes an output gear200that is rotatable about the output axis58. Optionally, the single-speed output portion94can include one or more speed reductions between the third gear104and the output gear200. In the example provided, the single-speed output portion94includes a pair of second compound gears210that provide the single-speed output portion94with two gear reductions between the third gear104and the output gear200.

Each of the second compound gears210includes a second layshaft212, a third intermediate gear214and a fourth intermediate gear216. The second layshaft212can be hollow and can be supported on opposite sides by first and second bearings220aand220, respectively, for rotation about a respective second intermediate axis222that is parallel to but offset from (i.e., not coincident with) both the motor axis70and the output axis58. The first bearing220acan be disposed between a first intermediate bearing mount that is formed by the first housing member30, and a first end of the second layshaft212, while the second bearing220bcan be disposed between a second intermediate bearing mount, which is formed by the second housing member32, and a second end of the second layshaft212that is opposite the first end. The third intermediate gear214is fixedly coupled to the second layshaft212for rotation therewith about the second intermediate axis222and includes gear teeth that are meshingly engaged with the gear teeth of the third gear104. The fourth intermediate gear216is fixedly coupled to the second layshaft212for rotation therewith about the second intermediate axis222and includes gear teeth that are meshingly engaged with gear teeth of the output gear200. In the example provided, the second compound gears210are arranged along the second intermediate axes222so that the third intermediate gears214are disposed farther away from the first gear100than the fourth intermediate gears216. Configuration in this manner permits the transmission16to be relatively compact in an axial direction (e.g., along the output axis58).

With reference toFIGS.5and8, the differential assembly18can include a differential input member230, which is coupled to the output gear200for rotation therewith, and a pair of differential output members232that are rotatable relative to the differential input member230about the output axis58. The differential assembly18can be configured in any desired manner. For example, the differential assembly18could be configured with a bevel gearset having (straight) bevel side gears and differential pinions, and the differential input member230could be a differential case that houses the side gears and the differential pinions. In the example provided, the differential assembly18is configured as a planetary or epicyclic differential assembly having an internal gear (not specifically shown), a sun gear (not specifically shown), a planet carrier (not specifically shown) and a plurality of sets of planet gears (not specifically shown). The internal gear can be fixedly coupled to (e.g., unitarily and integrally formed with) the output gear200of the transmission16. The sun gear is disposed concentrically within the internal gear and is rotatable about the output axis58. The planet carrier is rotatable about the output axis58. Each of the sets of planet gears is meshed with both the internal gear and the sun gear and includes one or more planet gears that are journally supported by the planet carrier. In situations where the sets of planet gears comprise two or more planet gears, each of the planet gears is meshed with another one of the planet gears, one of the planet gears is meshed with the internal gear, and a different one of the planet gears is meshed with the sun gear. In the example shown, each set of planet gears comprises a first planet gear, which is meshingly engaged to the internal gear and journally supported by the planet carrier, and a second planet gear that is meshingly engaged to both the first planet gear and the sun gear and which is also journally supported by the planet carrier. In this configuration, the sun gear and the planet carrier are the differential output members232of the differential assembly18. The differential bearings54can be mounted radially between the gearcase and hubs (not specifically shown) formed on the planet carrier to support the differential input member230for rotation about the output axis58. In the example shown, the differential bearings54are tapered roller bearings that additionally provide support to the differential assembly18in an axial direction along the output axis58.

With reference toFIGS.2and5, each of the axle shafts20is received through a corresponding one of the axle tubes34and is coupled for rotation with a corresponding one of the differential output members232. Various bearings (not specifically shown) can be employed to support the axle shafts20relative to the housing assembly12. In the example provided, the multi-speed electric drive axle10has a “full floating” axle configuration in which the axle shafts20are rotationally coupled to wheel hubs250that are supported (axially and rotationally) on the axle tubes34so that the axle shafts20transmit rotational torque between the differential assembly18and an associated vehicle wheel (not shown) but do not carry the weight of the vehicle. It will be appreciated, however, that the multi-speed electric drive axle10could be configured differently and that it could have any desired configuration (e.g., semi-floating, three-quarters floating, independent).

With reference toFIGS.3,9and14, the mounting plate90includes a mounting plate body260, flange member262, a plurality of bearing mounts (a bearing mount264a, a bearing mount264band the second intermediate bearing mount152), and a lubrication gallery266. The flange member262is fixedly coupled to and extends about the mounting plate body260. The flange member262is configured to abut an interior or inboard surface of the first housing member30. A plurality of threaded fasteners can be received through the flange member262and can be threadably engaged to corresponding threaded holes (not specifically shown) in the first housing member30to secure the mounting plate90to the first housing member30. A locating means, such as one or more dowel pins or a pair of roll pins, can be employed to position or locate the mounting plate90relative to the first housing member30. The mounting plate body260can be contoured to form a space or cavity that can accommodate the gear teeth of the third gear104and the first intermediate gear142.

The bearing mount264ais disposed on a first side of the mounting plate body260(i.e., a side that faces the first housing member30) and is configured to receive one of the bearings126that supports the second gear102. The bearing mount164bis disposed on a second, opposite side of the mounting plate body260(i.e., a side that faces the second housing member32) and is configured to receive one of bearings (i.e., bearing136a) that supports the third gear104. The second intermediate bearing mount152is formed on the first side of the mounting plate body260and is configured to receive the bearing146bthat supports the first layshaft140of the first compound gear106.

With reference toFIGS.14and15, the lubrication gallery266includes an inlet port270, one or more fluid passages (e.g., fluid passages272,274and276), and one or more fluid outlets (e.g., an outlet nozzle278, and/or one or more outlet orifices (not specifically shown)). The inlet port270is configured to be coupled in fluid communication to a source or flow of pressurized lubricating fluid. In the example provided, the inlet port270is coupled in fluid communication to a hose280that provides pressurized lubricating fluid to the lubrication gallery266. The fluid passages are generally configured to route the pressurized lubricating fluid through the mounting plate90between the inlet port270and the fluid outlets. In the example provided, a first fluid passage272receives pressurized lubricating fluid from the inlet port270and transmits the pressurized lubricating fluid to second and third fluid passages274and276, respectively, and to the outlet nozzle278. The outlet nozzle278supplies pressurized lubricating fluid to both the second intermediate bearing mount152(for lubrication of both the second bearing146band the teeth of the second intermediate gear144), as well as to the hollow interior of (i.e., a longitudinal passage in) the first layshaft140. Pressurized lubricating fluid that travels through the first layshaft140can be transmitted into the first intermediate bearing mount150and employed to lubricate both the first bearing146aand the teeth of the first intermediate gear142. The outlet orifices can be located and sized to provide lubrication in desired areas, such as the bearing146band/or the teeth of the third gear104. Additionally or alternatively, one or more of the fluid passages in the mounting plate90could transmit pressurized lubricating fluid into the first housing member30, for example for lubrication of various bearings (e.g., the bearings that are mounted in the first housing member30and support the second compound gears210), and/or gear meshes.

With reference toFIGS.16through19, the multi-speed input portion92of the transmission16can further include an actuator assembly300that is configured to move the input shaft108between the high-speed, neutral and low-speed positions. The actuator assembly300can be configured in any manner desired, but in the particular example provided, includes an output assembly300, a lead screw304, a coupler306, first and second actuator bearings308and310, and an actuator motor312.

The output assembly300can include a bearing320and an axially movable member322. The bearing320can be received over the input shaft108and can be abutted against a shoulder that is formed on the input shaft108. The axially movable member322can extend between the motor axis70and a rotational axis of the lead screw304and can define a bearing aperture and a coupler mount330that are disposed on its opposite ends. The bearing320is received in the bearing aperture and can be fixedly coupled to the axially movable member322in any desired manner. In the example provided, an internal snap ring is mounted into a snap-ring groove that is formed into the axially movable member322concentric with the bearing aperture b4 and on an axial end of the bearing320that is opposite the axial end of the bearing320that abuts the shoulder on the input shaft108. Accordingly, the axially movable member322is coupled to the input shaft108in a manner that inhibits relative axial movement between the axially movable member322and the input shaft108but which permits rotation of the input shaft108relative to the axially movable member322.

The lead screw304is rotatably disposed about a lead screw axis and includes a lead screw input340and an externally threaded portion342.

With reference toFIGS.19A-19C, the coupler306can have an internally threaded hub350and a mounting flange352that can be mounted to the coupler mount330. The internally threaded hub350can be threaded onto the externally threaded portion342of the lead screw304. It will be appreciated that the mounting flange352and the coupler mount330can be configured in any desired manner. In the example provided, the mounting flange352has a non-circular cross-sectional area (taken perpendicular to the longitudinal axis of the internally threaded hub350) and the coupler mount330defines a pocket330ainto which a portion of the mounting flange352is received so that the mounting flange352is axially and non-rotatably coupled to the coupler mount330. Accordingly, rotation of the lead screw304causes corresponding translation of both the coupler306and the output assembly300.

Optionally, one or more coupler pads1000can be coupled to the mounting flange352and can extend from one or both sides of the mounting flange352. The coupler pads1000can contact an interior surface of the pocket330ain the coupler mount330. The coupler pads1000can be employed for various purposes, such as helping to direct forces that are transmitted between the coupler306and the axially movable member322in a desired manner, and/or providing vibration damping between the coupler306and the axially movable member322.

With reference toFIGS.19B and19D-19G, the coupler pads1000can have a pad member900and a projection902. The pad member900has a first surface1002, which abuts an interior surface of the pocket330a, and a second surface1004that abuts an associated front or rear axial surface of the coupler306. One of the first and second surfaces1002and1004of the pad member1002is curved so that contact between each coupler pad1000and the one of the coupler306and the axially movable member322occurs over an associated line that extends in a plane P that includes the rotational axis SA of the lead screw304and is parallel to a shift axis (i.e., the axis along which movement causes shifting, which is the motor axis70in the example provided). The projection902can be configured to be received into an aperture908that can be formed in the coupler306or the coupler mount330such that the projection902is coupled to the coupler306or the coupler mount330with a snap or interference fit. In the example provided, the projections902are fitted into apertures908that are formed in the coupler306.

The first and second bearings308and310can be mounted to the gearcase and can support the lead screw304for rotation about the lead screw axis.

The actuator motor312is configured to provide rotary power to drive the lead screw304about the lead screw axis. The actuator motor312can be directly coupled to the lead screw input or a speed reduction, such as a reduction gearset, can be disposed between the actuator motor312and the lead screw input. In the example provided, a reduction gearset that utilizes bevel gearing is employed. More specifically, the reduction gearset comprises an actuator input gear360, which is directly driven by the actuator motor312about an axis that is perpendicular to the lead screw axis, and an actuator output gear362that is meshingly engaged with the actuator input gear360and rotatable about the lead screw axis. It will be appreciated that the reduction gearset could be configured differently and need not utilize bevel gearing. The actuator output gear362can be coupled to the lead screw input in any desired manner. For example, the actuator output gear362can be directly coupled to the lead screw input so that the lead screw304rotates directly with the actuator output gear362. Alternatively, a torsionally resilient coupling could be employed between the actuator output gear362and the lead screw input340to provide compliance in one or both rotational directions between the actuator output gear362and the lead screw304. In the example provided, a torsionally resilient coupling permits the actuator output gear362to rotate in instances where the input shaft108is not able to translate (e.g., due to: 1) tooth-on-tooth contact between one of the sets of external splines on the input shaft and one of the sets of internal splines on one of the first or third gears or between the first and second face teeth; or 2) the magnitude of the torque that is exerted through the input shaft108, i.e., torque loading).

With reference toFIGS.16and19through22, a park-lock mechanism400can be incorporated into the multi-speed electric drive axle10(FIG.1). In the example provided, the park-lock mechanism400is configured to inhibit rotation of the third gear104to inhibit rotation of the differential input member230(FIG.5) and thereby inhibit rotation of the differential output members232(FIG.5). The park-lock mechanism400can include a park-lock gear402, a pivot pin404, a park pawl406, and a park-lock plunger assembly408.

The park-lock gear402can be fixedly coupled to the third gear104and can define a plurality of park-lock teeth and a plurality of valleys420that are each disposed circumferentially between an associated pair of the park-lock teeth. The pivot pin404can be received into a pivot pin aperture formed in the second housing member32and can be rotatable about a pivot axis relative to the second housing member32. In the example provided, the pivot pin404is mounted on a bracket424.

The park pawl406includes a pawl body430which is coupled to the pivot pin404for rotation about the pivot axis, and a pawl member432that is fixedly coupled to the pawl body430. The pawl body430can pivot relative to the park-lock gear402between a first or locked position, in which the park pawl406is received into a valley420to thereby inhibit rotation of both the park-lock gear402and the third gear104about the motor axis70, and a second or unlocked position in which the park pawl406is disengaged from the park-lock gear402and does not inhibit rotation of the park-lock gear402about the motor axis70. The park-pawl406can optionally include a guide structure438that can be mounted to the second housing member32. The guide structure438can have a guide member that can guide the pawl body430as it moves between the first and second positions. Movement of the guide structure438caused by corresponding movement of the plunger450can cause corresponding pivoting motion of the pawl body430about the pivot pin404.

A biasing spring, such as a torsion spring440, can be employed to bias the pawl body430into the second position. In the example provided, the torsion spring440has a helically coiled portion that is received over the pivot pin404and disposed between two arms. An end of a first one of the arms is mounted to the bracket424, while an end of the other one of the arms is mounted to the pawl body430. A feature, such as a head or a washer, can be formed on or coupled to the pivot pin404to trap the helically coiled portion of the torsion spring440on the pivot pin404on a side of the bracket424that is opposite the park pawl406.

The park-lock plunger assembly408can include a plunger450, an input member452and a compliance spring454. The plunger450is movable along an axis that is parallel to the motor axis70and has a generally cylindrical first plunger portion, a generally cylindrical second plunger portion and a transition portion that tapers between the first and second plunger portions. The first plunger portion has a first diameter, the second plunger portion is spaced apart from the first plunger portion and has a second, larger diameter, and the transition portion is disposed and tapers between the first and second plunger portions so that the transition portion has a frustoconical exterior surface. The plunger450can be translated between a first plunger position, in which the first plunger portion is in contact with the park pawl406, and a second plunger position in which either the transition portion or the second plunger portion is in contact with the park pawl406. The first plunger portion is sized so that the pawl body430of the park pawl406is disposed in the second position when the first plunger portion is engaged to (directly contacts) the pawl body430. Translation of the plunger450from the first plunger position to the second plunger position causes relatively larger portions of the plunger450to contact the pawl body430, which pivots the pawl body430toward the second pawl position.

The input member452is movable about the translation axis of the plunger450and can be moved in any desired manner. In the example provided, an electric park-lock motor460and a manual park-lock input lever462are provided as alternative or redundant inputs for the operation of the park-lock mechanism400, while an output lever464is employed to coordinate movement of the input member452. More specifically, the output lever464is coupled to the input member452and is pivotably coupled to the second housing member32for movement between a first input position and a second input position. The manual park-lock input lever462is fixedly coupled to a portion of the output lever464that extends through the second housing member32(i.e., so that the manual park-lock input lever462is disposed outside the gearcase). Pivoting motion of the manual park-lock input lever462about the pivot axis of the output lever464causes corresponding pivoting motion of the output lever464about the pivot axis of the output lever464. The electric park-lock motor460is mounted to an exterior surface of the second housing member32and includes an output shaft470that extends into the transmission cavity38. An intermediate lever472is coupled to the output shaft470of the electric park-lock motor460and can be moved by the electric park-lock motor460about the rotational axis of the output shaft470between a first intermediate lever position and a second intermediate lever position. An end of the intermediate lever472that is opposite the output shaft470includes a pin that is received into a slotted aperture in the output lever464. Movement of the intermediate lever472from the first intermediate lever position to the second intermediate lever position (in response to rotation of the output shaft470) causes pivoting motion of the output lever464about its pivot axis from the first input position to the second input position. The slotted aperture in the output lever464permits the output lever464to be moved about its pivot axis from the first input position to the second input position without corresponding motion of the intermediate lever472.

The compliance spring454is disposed between the input member452and the plunger450and permits the pawl body430to push the plunger450away from the pawl body430when the output lever464is disposed in the second input position. It will be appreciated that placement of the output lever464in the second input position places the input member452into a position that would ordinarily position the plunger450in the second plunger position. However, in situations where the pawl member432is not able to drop into a valley420or remain in a valley420, the park pawl406can translate the plunger450toward the compliance spring454to compress the compliance spring454so that the park-lock gear402is able to rotate.

Significant portions of both the actuator assembly300and the park-lock mechanism400can be assembled to the second housing member32before it is assembled to the first housing member30to close the transmission cavity38and the differential cavity40. In this regard, all or portions of the reduction gearset (e.g., the actuator input gear360and the actuator output gear362in the example provided), the bearings308and310, the lead screw304, the torsionally resilient coupling (if included) and optionally the coupler306and/or the actuator motor312of the actuator assembly300can be installed to the second housing member32prior to the mounting of the second housing member32to the first housing member30. Additionally or alternatively, all of the components of the park-lock mechanism400except for the park-lock gear402can be assembled to the second housing member32prior to the mounting of the second housing member32to the first housing member30.

With reference toFIG.23, the actuator assembly300ahas an actuator transmission500that transmits rotary power between the actuator motor312and the coupler306a. In this example, the lead screw304ais non-rotatably but axially slidably coupled to the housing assembly12a, and an actuator output gear502of the actuator transmission500is fixedly coupled to the coupler306a. Accordingly, the actuator motor312can be operated to rotationally drive the actuator output gear502. Since the coupler306ais fixedly coupled to the actuator output gear502and threadably coupled to the lead screw304a, rotation of the actuator output gear502causes corresponding rotation of the coupler306a, which in turn causes translation of the lead screw304aalong the motor axis70. The lead screw304acan be coupled to the input shaft108in a manner that permits relative rotation but inhibits relative axial movement along the motor axis70. In the example provided, a bearing504is mounted between the lead screw304aand the input shaft108. The bearing504is configured to transmit thrust loads along the motor axis70between the lead screw304aand the input shaft108and can optionally rotationally support radial loads transmitted between the lead screw304aand the input shaft108. If desired, lubricating oil (represented by the arrow A) can be transmitted through the lead screw304ainto the hollow interior of the input shaft108. Optionally, a sensor510can be mounted to the housing assembly12and can be configured to sense a position of the lead screw304aalong the motor axis70and responsively generate a sensor signal.

InFIG.24, a portion of another multi-speed electric drive axle10bis illustrated. The transmission16bof the multi-speed electric drive axle10bis configured with a planetary configuration having a sun gear600, a planet carrier602, a plurality of planet gears604and a ring gear606that is fixedly coupled to the housing assembly12. Each of the planet gears604can be a single gear that is journally supported by the planet carrier602and meshingly engaged to both the sun gear600and the ring gear606. Alternatively, each of the planet gears606can comprise two or more gears that are meshed together and journally supported by the planet carrier602, with one of the gears being meshingly engaged to sun gear600and another one of the gears being meshingly engaged to the ring gear606. The input shaft108is slidable between a first position, in which the input shaft108is rotationally coupled only to the sun gear600so that the transmission16boperates in a first speed ratio, and a second position in which the input shaft108is rotationally coupled to both the sun gear600and the planet carrier602so that the transmission16boperates in a second speed ratio that is different from the first speed ratio.

In the example ofFIG.25, the transmission16dincludes an auxiliary reduction stage698comprises first and second intermediate gears700and702, respectively, and a layshaft gear pair having a first layshaft gear704, which is meshingly engaged with the first intermediate gear700, and a second layshaft gear706that is coupled to the first layshaft gear704for rotation therewith and meshingly engaged with the second intermediate gear702. The first and second intermediate gears700and702are rotatably mounted on the input shaft108, a mating spline portion714is formed on the first intermediate gear700and a mating spline portion712is formed on the second intermediate gear702.

When the input shaft108is positioned in the first position, a spline portion720on the motor output shaft72is engaged with a spline portion730formed on the input shaft108to thereby rotatably couple the input shaft108to the motor output shaft72, another spline portion732on the input shaft108is engaged with a mating spline portion742on a first drive gear744to thereby rotatably couple the first drive gear744to the input shaft108, a spline portion750on the input shaft108, the spline portion750on the input shaft108is disengaged from the mating spline portion714of the first intermediate gear700, and the spline portion752on a coupling sleeve754is engaged only with the mating spline portion712of the second intermediate gear702. Consequently, the auxiliary reduction stage698is not employed in the transmission of rotary power between the electric motor14and the differential assembly18. It will be appreciated that while the spline portion752on the coupling sleeve754is engaged to the mating spline portion712of the second intermediate gear702, no rotary power is transmitted between the second intermediate gear702and the input shaft108because the coupling sleeve754is rotatable relative to the input shaft108. It will be appreciated that the first drive gear744is meshingly engaged to an intermediate gear744athat is fixed to a layshaft, that a layshaft output gear that is fixedly coupled to the layshaft and meshingly engaged with an output gear that is coupled to the differential input member230for common rotation.

Movement of the input shaft108from the first position to the second position disengages the spline portion732on the input shaft108from the mating spline portion742on the drive gear744but leaves the spline portion720on the motor output shaft72engaged with the mating spline portion730on the input shaft108, the spline portion750on the input shaft108disengaged from the mating spline portion714of the first intermediate gear700, and the spline portion752on a coupling sleeve754is only engaged to the mating spline portion712of the second intermediate gear702. In this position, no rotary power is transmitted between the drive gear744and the motor output shaft72and as such, the transmission16doperates in a “neutral” condition so that rotary power is not transmitted between the differential input member230and the motor output shaft72.

Movement of the input shaft108from the second position to the third position engages the spline portion750on the input shaft108to the mating spline portion714of the first intermediate gear700and engages the spline portion752on a coupling sleeve754to the mating spline portion760on the second drive gear762, while leaving the spline portion720on the motor output shaft72engaged with the mating spline portion730on the input shaft108, the spline portion732on the input shaft108disengaged from the mating spline portion742on the drive gear744, and the spline portion752on a coupling sleeve754engaged with the mating spline portion712of the second intermediate gear702. In this position, rotary power provided by the motor output shaft72is transmitted to the first intermediate gear700(via the spline portion750on the input shaft108and the mating spline portion714of the first intermediate gear700). The auxiliary reduction stage698performs a speed reduction and torque multiplication function a first speed reduction and torque multiplication function is provided by the first intermediate gear200and the first layshaft gear204, and a second speed reduction and torque multiplication function is provided by the second layshaft gear206and the second intermediate gear702. The coupling sleeve754rotatably couples the second intermediate gear702to the second drive gear762to drive the second drive gear762about the motor axis70. It will be appreciated that when the input shaft108is positioned in the third position, the second drive gear762is driven at a reduced speed relative to the rotational speed of the first drive gear744when the input shaft108is in the first position because the auxiliary reduction stage698is actively employed in the transmission of rotary power between the motor output shaft72and the differential assembly18when the input shaft108is in the third position (i.e., the second drive gear762is operated at a reduced rotational speed relative to the rotational speed of the motor output shaft72due to the speed reduction that is provided by the auxiliary reduction stage698). It will be appreciated that the second drive gear762is drivingly engaged to another intermediate gear762athat is fixed to the layshaft to thereby drive the layshaft and the layshaft output gear.

It will be appreciated that the first intermediate input gear744, the second intermediate input gear700, the third intermediate gear702and the fourth intermediate gear762are coaxial with the input shaft108and are rotatable relative to the input shaft108in at least one of a first speed ratio and a second speed ratio. Additionally, the input shaft108is axially movable along the motor axis70between a first position, in which a first one of the at least three on-axis gears (i.e., first intermediate input gear744, the second intermediate input gear700, the third intermediate gear702and the fourth intermediate gear762) is rotationally coupled to the input shaft108, and a second position in which a second, different one of the at least three on-axis gears is rotationally coupled to the input shaft.