Abstract:
A power transmitting component having a actuator with a lead screw, which is driven by a motor and a transmission, a pusher assembly driven by the lead screw, and first and second clutch forks. Translation of the pusher coordinates movement of the first and second clutch forks along respective axes.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/869,282, U.S. Provisional Patent Application No. 61/869,295, and U.S. Provisional Patent Application No. 61/869,312, each of which having been filed on Aug. 23, 2013. The disclosures of the above applications are incorporated by reference as if set forth herein in their entirety. 
    
    
     FIELD 
     The present disclosure relates to a power transmitting component with a twin-fork actuator. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     Modern vehicle manufacturers have expressed increasing interest in four-wheel drive vehicle drivelines that are capable of operation in a two-wheel, high-speed drive mode as well as in a four-wheel, low-speed drive mode. Such drivelines typically include a variety of power transmitting components that may include clutches and/or transmissions that would need to be operated in two or more modes to provide the drivetrain with the desired functionality. Some of the known clutches and transmissions employed in such drivelines employ a pair of actuators (for controlling the operation of the clutch and the transmission), each of which utilizing a fork for axially sliding an element of the clutch or transmission. While such configurations work for their intended purpose, such power transmitting components are nevertheless susceptible to improvement. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     In one form, the present teachings provide a power transmitting component that includes an actuator housing, a motor coupled to the actuator housing, a transmission, a lead screw, a first rail, a second rail, a cradle assembly, a first fork and a second fork. The transmission is driven by the motor and at least partially housed in the actuator housing. The lead screw is rotatable about a first axis, the lead screw being driven by the transmission. The first rail extends along a second axis that is generally parallel to the first axis. The second rail extends along a third axis that is generally parallel to the first axis. The cradle assembly is driven by the lead screw axially along the first axis and includes a cradle having a first cradle yoke, which is slidably received on the first rail, and a second cradle yoke that is slidably received on the second rail. The first clutch fork is slidably mounted on the first rail. The second clutch fork is slidably mounted on the second rail. Movement of the cradle along the first rail coordinates movement of the first clutch fork along the second axis and movement of the second clutch fork along the third axis. 
     In another form, the present teachings provide a method for operating a power transmitting component having a first power transmitting member, a second power transmitting member and a collar. The first and second power transmitting members are rotatable along an axis. The collar is rotatably and slidably mounted to the first power transmitting member. The collar is axially movable along the axis between a fully disengaged position, in which the collar is disengaged from the second power transmitting member, and a fully engaged position. The method includes: providing an actuator with an electric motor and a clutch fork that is driven by the electric motor, the clutch fork being engaged to the collar; translating the collar to the fully disengaged position; generating a command to move the clutch fork to the engaged position and responsively operating the electric motor to cause the clutch fork to move the collar toward the fully engaged position; determining a position of the collar along the axis after the electric motor has halted operation; and limiting rotary power transmitted through the collar if the collar is not located in the fully engaged but is nevertheless engaged to the second power transmitting member to at least a predetermined extent. 
     In a further form, the present teachings provide a power transmitting component that includes a power take-off unit and an actuator. The power take-off unit has a mode clutch and a multi-speed transmission. The mode clutch has a mode member that is axially movable along a transmission axis between a first mode position, in which no rotary power is transmitted through the mode clutch, and a second mode position in which rotary power is transmitted through the mode clutch. The multi-speed transmission has a transmission member that is movable along the transmission axis between a first transmission position, in which the transmission operates in a first gear ratio, and a second transmission position in which the transmission operates in a second, different gear ratio. The actuator has an actuator housing, a motor coupled to the actuator housing, an actuator transmission, a lead screw, a first rail, a second rail, a cradle assembly, a first clutch fork, a second clutch fork, a first fork spring and a second fork spring. The actuator transmission is driven by the motor and is at least partially housed in the actuator housing. The lead screw is driven by the actuator transmission for rotation about a first axis. The first rail extends along a second axis that is generally parallel to the first axis. The second rail extends along a third axis that is generally parallel to the first axis. The cradle assembly includes a cradle, a cradle body, and a cradle spring. The cradle defines a first cradle yoke, which is slidably mounted on the first rail, a second cradle yoke, which is slidably mounted on the second rail, a first drive lug and a pair of arms. The cradle body is threadably coupled to the lead screw such that rotation of the lead screw causes corresponding axial movement of the cradle body along the first axis. The cradle spring is configured to center the cradle body between the arms of the cradle and to permit movement of the cradle body relative to the cradle along the first axis. The first clutch fork has a first clutch fork yoke, which is slidably mounted on the first rail, and a second drive lug. The first clutch fork is engaged to one of the mode member and the transmission member such that movement of the first clutch fork along the second axis causes corresponding movement of the one of the mode member and the transmission member along the transmission axis. The second clutch fork has a second clutch fork yoke, which is slidably mounted on the second rail, and a third drive lug. The second clutch fork is engaged to the other one of the mode member and the transmission member such that movement of the second clutch fork along the third axis causes corresponding movement of the other one of the mode member and the transmission member along the transmission axis. The first fork spring is received on the first rail and biasing the first clutch fork and the first cradle yoke apart from one another. The second fork spring is received on the second rail and biasing the second clutch fork and the second cradle yoke apart from one another. The first clutch fork is movable between a first fork position and a second fork position. The second clutch fork is movable between a third fork position and a fourth fork position. The first and second drive lugs contact one another over at least a portion of the travel of the first clutch fork when the first clutch fork is moved from the first fork position to the second fork position. The third drive lug contacts the actuator housing when the second clutch fork is in the fourth fork position. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a schematic illustration of a vehicle having a power transmitting component with a twin-fork actuator constructed in accordance with the teachings of the present disclosure; 
         FIG. 2  is a perspective view of the power transmitting component of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a portion of the power transmitting component of  FIG. 1 ; 
         FIG. 4  is a section view taken along the line  4 - 4  of  FIG. 2 ; 
         FIG. 5  is a section view taken along the line  5 - 5  of  FIG. 2 ; 
         FIGS. 6-9  are enlarged section views of a the power transmitting component of  FIG. 1  illustrating the range and mode collars in a high-range, two-wheel drive mode, a high-range, four-wheel drive mode, a neutral mode, and a low-range, four-wheel drive mode, respectively; 
         FIG. 10  is an exploded perspective view of the twin-fork actuator; 
         FIG. 11  is a perspective of a portion of the twin-fork actuator illustrating the motor, transmission and a portion of the actuator housing in more detail; 
         FIG. 12  is a top view of the twin-fork actuator with a top portion of the actuator housing removed; 
         FIG. 13  is a bottom view of a portion of the twin-fork actuator; 
         FIG. 14  is a section view through the twin-fork actuator taken through the center of the first and second rails; 
         FIG. 15  is a top view of a portion of the twin-fork actuator; 
         FIG. 16  is a perspective view of a portion of the twin-fork actuator; and 
         FIG. 17  is a schematic illustration of a portion of another twin-fork actuator having a locking mechanism for locking the range and/or mode forks in corresponding desired positions. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     With reference to  FIG. 1  of the drawings, an exemplary vehicle having a power transmitting component constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral  10 . The vehicle  10  can have a power train  12  and a drive line or drive train  14 . The power train  12  can be conventionally constructed and can comprise a power source  16  and a transmission  18 . The power source  16  can be configured to provide propulsive power and can comprise an internal combustion engine and/or an electric motor, for example. The transmission  18  can receive propulsive power from the power source  16  and can output power to the drive train  14 . The transmission  18  can have a plurality of automatically or manually-selected gear ratios. The drive train  14  in the particular example provided is of an all-wheel drive configuration, but those of skill in the art will appreciate that the teachings of the present disclosure are applicable to other drive train configurations, including four-wheel drive configurations, rear-wheel drive configurations, and front-wheel drive configurations. 
     The drive train  14  can include the power transmitting component, which can include a front axle assembly  20  and a power take-off unit (PTU)  22 , a prop shaft  24  and a rear axle assembly  26 . An output of the transmission  18  can be coupled to an input of the front axle assembly  20  to drive an input member  30  of the front axle assembly  20 . The PTU  22  can have a PTU input member  32 , which can receive rotary power from the input member  30  of the front axle assembly  20 , and a PTU output member  34  that can transmit rotary power to the prop shaft  24 . The prop shaft  24  can couple the PTU output member  34  to the rear axle assembly  26  such that rotary power output by the PTU  22  is received by the rear axle assembly  26 . The front axle assembly  20  and the rear axle assembly  26  could be driven on a full-time basis to drive front and rear vehicle wheels  36  and  38 , respectively. It will be appreciated, however, that the drive train  14  could include one or more clutches to interrupt the transmission of rotary power through a part of the drive train  14 . In the particular example provided, the drive train  14  include a mode or first clutch  40 , which can be configured to interrupt the transmission of rotary power into or through the PTU  22 , and a second clutch  42 , which can be configured to halt rotation of components within the rear axle assembly  26 . 
     With reference to  FIGS. 2 and 4 , the front axle assembly  20 , the PTU  22  and the mode clutch  40  are illustrated in more detail. The front axle assembly  20 , the PTU  22  and the mode clutch  40  can be mounted in a housing assembly  50  and can be constructed in a manner that is described in co-pending U.S. patent application Ser. No. 13/470,941 filed May 14, 2012 and entitled “Disconnectable Driveline For All-Wheel Drive Vehicle”. The housing assembly  50  can be constructed in a manner that is described in co-pending U.S. patent application Ser. No. 13/792,355 filed Mar. 11, 2013 and entitled “Power Transmitting Component With Multi-Part Housing Assembly Having Continuous Sealing Flange”. The entire disclosures of U.S. patent application Ser. No. 13/470,941 and U.S. patent application Ser. No. 13/792,355 are incorporated by reference as if set forth in their entirety herein. 
     With reference to  FIGS. 2 and 3 , the housing assembly  50  can include a first housing structure  60 , a second housing structure  62  and a gasket  64  that can be received between the first and second housing structures  60  and  62 . The first and second housing structures  60  and  62  can be fixedly but removably coupled to one another to define a cavity  66  and a shaft bore  68  ( FIG. 4 ). The shaft bore  68  ( FIG. 4 ) can be formed through the housing assembly  50  along a shaft axis  70  and can intersect the cavity  66 . The first housing structure  60  can include a first housing member  76  and a second housing member  78  that can be fixedly but removably coupled to the first housing member  76 . The first housing structure  60  can define an input member axis  92 . The second housing structure  62  can define a pinion bore  110  ( FIG. 5 ) that can be arranged about a pinion axis  112  that can be perpendicular to the shaft axis  70 . 
     With reference to  FIG. 4 , the front axle assembly  20  can include the input member  30 , a two-speed transmission  150 , a front differential assembly  152  and a pair of front axle shafts  154  (only one is shown for clarity). The input member  30  can be a hollow shaft having a plurality of internal teeth or splines  160 , which can be disposed on a first axial end of the input member  30  and configured to engage with the output member (not shown) of the transmission  18  ( FIG. 1 ), and a set of first (external) range teeth  162  formed on a second, opposite end. The two-speed transmission  150  can include an input shaft  170 , a sun gear  172 , a plurality of planet gears (not specifically shown), a planet carrier  176 , a ring gear  178  and a range collar  180 . The input shaft  170  can be a hollow structure that can be co-axial with the input member  30 . A needle bearing  190  can be disposed between the input shaft  170  and the input member  30 . The input shaft  170  can have a set of second (external) range teeth  192  formed on an end adjacent to the input member  30 . The sun gear  172  can be mounted on an end of the input shaft  170  opposite the second (external) range teeth  192  and can be coupled to the input shaft  170  for rotation therewith. The planet gears can be meshingly engaged with the sun gear  172  and the ring gear  178 . The planet carrier  176  can include a carrier body  196  and a plurality of pins (not specifically shown) that can be fixedly coupled to the carrier body  196  for rotation therewith. The carrier body  196  can have a set of third (external) range teeth  198 . The ring gear  178  can be meshingly engaged to the planet gears and can be non-rotatably coupled to the first housing member  76 . A shoulder  94  on the second housing member  78  can clamp the ring gear  178  against a shoulder  208  in the first housing member  76  to inhibit axial movement of the ring gear  178  relative to the first housing structure  60 . 
     The range collar  180  can be a tubular sleeve that can be mounted on the input shaft  170 . The range collar  180  can include fourth, fifth and sixth sets of (internal) range teeth  210 ,  212  and  214 , respectively, that can be axially separated from one another, and a collar member  216 . The fourth set of (internal) range teeth  210  can be slidably engaged to the first set of (external) range teeth  162  on the input member  30  so that the range collar  180  is coupled to the input member  30  for rotation therewith. The collar member  216  of the range collar  180  can be engaged to an actuator A ( FIG. 2 ) to permit the range collar  180  to be moved axially between first, second and third range positions. Any type of actuator (not specifically shown) can be employed, but in the example illustrated, the actuator comprises an axially movable range fork  220  having a groove into which the collar member  216  is received. 
     In the first range position, which is shown in  FIGS. 6 and 7 , the fifth set of (internal) range teeth  212  is decoupled from the second set of (external) range teeth  192  on the input shaft  170  and the sixth set of (internal) range teeth  214  is coupled to the set of third (external) range teeth  198  on the carrier body  196  to thereby provide a “high-speed condition” in which the two-speed transmission  150  ( FIG. 4 ) operates in a first or high-speed gear reduction. 
     In the second range position, which is shown in  FIG. 8 , the fifth set of (internal) range teeth  212  is decoupled from the second set of (external) range teeth  192  on the input shaft  170  and the sixth set of (internal) range teeth  214  is decoupled from the set of third (external) range teeth  198  on the carrier body  196  to thereby provide a “neutral condition” in which rotary power is not transmitted through the two-speed transmission  150  ( FIG. 4 ), the front differential assembly  152  ( FIG. 4 ) or the PTU  22  ( FIG. 4 ). 
     In the third range position, which is illustrated in  FIG. 9 , the sixth set of (internal) range teeth  214  is coupled to the second set of (external) range teeth  192  on the input shaft  170  and the sixth set of (internal) range teeth  214  is decoupled from the set of third (external) range teeth  198  on the carrier body  196  to thereby provide a “low-speed condition” in which the two-speed transmission  150  ( FIG. 4 ) operates in a second or low-speed gear reduction. 
     Returning to  FIG. 4 , the front differential assembly  152  can include a differential case  230 , a pair of output members  232  and a means for permitting speed differentiation between the output members  232 . The differential case  230  can be coupled to the carrier body  196  for rotation therewith such that the differential case  230  is rotatable about the input member axis  92 . The differential case  230  can house the output members  232  and the speed differentiation means. In the example provided, the speed differentiation means comprises an open differential gearset  236  that has a pair of side gears  238  and the output members  232  can comprise portions (e.g., an internally-splined bore) of the side gears  238  to which the front axle shafts  154  are non-rotatably coupled. It will be appreciated, however that other speed differentiation means could be employed in the alternative, such as one or more clutches, a locking differential or a limited slip differential. Moreover, while the differential gearset  236  is illustrated as having bevel pinions and sidegears, it will be appreciated that the pinions and sidegears could have a parallel-axis configuration in which the pinions and side gears have spur or helical gear teeth. 
     The front axle shafts  154  can have a male-splined segment that can be non-rotatably coupled to the output members  232  such that the front axle shafts  154  are rotatably driven by the output members  232 . One of the front axle shafts  154  can be received through the input shaft  170  and the input member  30 . 
     With reference to  FIGS. 4 and 5 , the PTU  22  can include the PTU input member  32 , a first intermediate gear  250 , a second intermediate gear  252 , a shaft  254 , a ring gear  256 , a pinion gear  258  and the PTU output member  34 . The PTU input member  32  can comprise a plurality of first (external) mode teeth  270  that can be fixedly coupled to the first intermediate gear  250 . The PTU input member  32  and the first intermediate gear  250  can be mounted in the first housing member  76  concentrically about the input member  30 . The second intermediate gear  252  can be meshingly engaged to the first intermediate gear  250 . The shaft  254  can be coupled to the second intermediate gear  252  for rotation therewith. A pair of shaft bearings  280  can support the shaft  254  for rotation relative to the housing assembly  50 . The ring gear  256  can be mounted on the shaft  254  on an end opposite the second intermediate gear  252 . The pinion gear  258  can be received in the pinion bore  110  in the second housing structure  62  and can be supported for rotation relative to the second housing structure  62  by a set of pinion bearings  300 . The pinion gear  258  can be meshingly engaged to the ring gear  256 . A bearing adjuster (not specifically shown) can be employed between the second housing structure  62  and one of the shaft bearings  280  to preload the shaft bearings  280  and/or to control the manner in which the teeth of the ring gear  256  are meshed with the teeth of the pinion gear  258 . The bearing adjuster can be constructed in a conventional manner and as such, need not be described in significant detail herein. The PTU output member  34  can be coupled to the pinion gear  258  for rotation therewith. 
     The mode clutch  40  can be a dog clutch that can be configured to selectively couple the PTU input member  32  to the input member  30 . The mode clutch  40  can have a clutch or mode collar  320  that can be received concentrically about the input shaft  170 . With additional reference to  FIG. 6 , the mode collar  320  can have a second (internal) set of mode teeth  322 , a third (internal) set of mode teeth  324 , and an annular collar member  326 . The collar member  326  can be engaged to an actuator, such as the actuator A ( FIG. 2 ), to permit the mode collar  320  to be moved axially along the input member axis  92  between a first mode position and a second mode position. Any type of actuator can be employed, but in the example provide, the actuator A ( FIG. 2 ) comprises an axially movable mode fork  330  having a groove  332  into which the collar member  326  is received. 
     In the first mode position, which is illustrated in  FIG. 6 , the mode collar  320  is axially separated from the PTU input member  32  such that the second (internal) set of mode teeth  322  are decoupled from the first (external) set of mode teeth  270  on the PTU input member  32 . In the particular example shown, the third (internal) set of mode teeth  324  are engaged to a fourth (external) set of mode teeth  340  formed on the range collar  180  and as such, the mode collar  320  will rotate with the range collar  180  but no rotary power will be transmitted to the PTU input member  32 . Consequently, the drive train  14  ( FIG. 1 ) will operate in a 2-wheel, high-speed mode. 
     In the second mode position, which is illustrated in  FIGS. 7 through 9 , the mode collar  320  is engaged to the PTU input member  32  such that the second (internal) set of mode teeth  322  are coupled to the first (external) set of mode teeth  270  on the PTU input member  32 . 
     In the example of  FIG. 7 , the third (internal) set of mode teeth  324  are engaged to the fourth (external) set of mode teeth  340  formed on the range collar  180  and as such the drive train  14  ( FIG. 1 ) can be operated in a 4-wheel, high-speed mode. In the example of  FIG. 8 , the third (internal) set of mode teeth  324  are decoupled from the fourth (external) set of mode teeth  340  formed on the range collar  180  and a fifth (external) set of mode teeth  342  formed on the range collar  180  and as such the drive train  14  ( FIG. 1 ) can be maintained in a neutral, non-driving condition. In the example of  FIG. 9 , the third (internal) set of mode teeth  324  are decoupled from the fourth (external) set of mode teeth  340  formed on the range collar  180  and coupled to the fifth (external) set of mode teeth  342  formed on the range collar  180  and as such the drive train  14  ( FIG. 1 ) can be operate in a 4-wheel, low-speed mode. 
     With reference to  FIG. 10 , the actuator A can include an actuator housing  1000 , a motor  1002 , a transmission  1004 , a bearing  1006 , a lead screw  1008 , a first rail  1010 , a second rail  1012 , a cradle assembly  1014 , the range fork  220 , the mode fork  330 , a first arm spring  1016 , a second arm spring  1018 , and a control system  1020 . 
     The actuator housing  1000  can include a first cover member  1030  and a second cover member  1032  that can be sealingly coupled to the first over member  1030  by any suitable means, such as a gasket or a sealing compound. With additional reference to  FIG. 11 , the first cover member  1030  can define a motor mount  1036 , a transmission mount  1038  and a first bearing mount  1040 . The motor  1002  can be fixedly coupled to the motor mount  1036 . The transmission mount  1038  can comprise two or more wall members  1042  that can support elements of the transmission  1004 . The first bearing mount  1040  can be configured to receive a portion of the bearing  1006 . 
     With reference to  FIGS. 10 and 12 , the second cover member  1032  can be coupled to the first cover member  1030  to cover the motor  1002  and the transmission  1004 . The second cover member  1032  can define a second bearing mount  1044 , a pair of first rail apertures  1046 , a pair of second rail apertures  1048  and a fork window  1050  through which the range fork  220  and the mode fork  330  can extend. The second bearing mount  1044  can cooperate with the first bearing mount  1040  to retain the bearing  1006  therebetween. 
     With renewed reference to  FIGS. 10 and 11 , the motor  1002  can be any means for providing rotary power, such as a brushed or brushless DC motor. The transmission  1004  can comprise any means for transmitting rotary power between the motor  1002  and the lead screw  1008 , such as two or more pulleys, two or more sprockets and/or two or more gears. For example, the transmission  1004  can comprise an input spur pinion  1054 , which can be mounted to the output shaft of the motor  1002  for rotation therewith, an output spur pinion  1056 , which can be coupled to the lead screw  1008  for common rotation, and a plurality of intermediate spur gears  1058  that can transmit rotary power between the input spur pinion  1054  and the output spur pinion  1056 . The intermediate spur gears  1058  can be mounted on axles  1060  that can be fixedly coupled to associated pairs of the wall members  1042 . The transmission  1004  can provide a desired overall reduction ratio, such as an overall reduction ratio of about 250:1 to about 750:1 and preferably a reduction ratio of about 475:1. 
     The bearing  1006  can be a ball bearing having an outer bearing race  1070 , which can be received in the first and second bearing mounts  1040  and  1044  to fixedly couple the outer bearing race  1070  to the actuator housing  1000 , an inner bearing race  1072 , which can support the lead screw  1008  for rotation about a first axis  1076 , and a plurality of bearing elements (not specifically shown) between the outer and inner bearing races  1070  and  1072 . 
     The lead screw  1008  can be unitarily and integrally formed and can comprise hub  1080  and a threaded portion  1082 . The hub  1080  can be received in the inner bearing race  1072  and can be coupled to the output spur pinion  1056  of the transmission  1004  for rotation therewith. 
     The first rail  1010  can be received in the first rail apertures  1046  and fixedly coupled to the second cover member  1032  in any desired manner, such as a press-fit. The first rail  1010  can extend along a second axis  1090  that can be generally parallel to the first axis  1076 . Similarly, the second rail  1012  can be received in the second rail apertures  1048  and fixedly coupled to the second cover member  1032  in any desired manner, such as a press-fit. The second rail  1012  can extend along a third axis  1092  that can be generally parallel to the first axis  1076 . 
     The cradle assembly  1014  can comprise a cradle  2000 , a cradle body  2002 , a keeper  2004 , one or more guides  2006  and a cradle spring  2008 . The cradle  2000  can comprise a central body  2020 , a first cradle yoke  2022 , a second cradle yoke  2024 , a third cradle yoke  2026 , a pair of arms  2028 , which can be coupled to opposite ends of the central body  2020 , a first cradle drive lug  2030  and a second cradle drive lug  2032 . Each of the first, second and third cradle yokes  2022 ,  2024  and  2026  can be coupled to the central body  2020 . The first and third cradle yokes  2022  and  2026  can be slidably received on the first rail  1010 , and the second cradle yoke  2024  can be slidably received on the second rail  1012 . In the particular example provided, the first cradle yoke  2022  is located between the second and third cradle yokes  2024  and  2026 . Each of the arms  2028  can be bifurcated to define a pair of branches  2040  with an arm aperture  2042  therebetween. Additionally, each of the arms  2028  can define a pair of first guide slots  2048  that can be partly formed through the arms  2028 . More specifically, each of the first guide slots  2048  can extend through an inboard side IS of an associated one of the arms  2028  but not an outboard side OS of the associated one of the arms  2028 . The first and second cradle drive lugs  2030  and  2032  can be disposed on the cradle  2000  at a location between the first cradle yoke  2022  and the second cradle yoke  2024 . In the particular example provided, the first and second cradle drive lugs  2030  and  2032  form the opposite faces of a single structure. 
     The cradle body  2002  can comprise a longitudinally extending body member  2050  and a head  2052  and can define a pair of second guide slots  2054 . The body member  2050  can have a threaded internal bore  2060  and a pair of flanks  2062 . The threaded internal bore  2060  can receive the threaded portion  1082  of the lead screw  1008  to threadably couple the cradle body  2002  to the lead screw  1008 . The head  2052  can be coupled to the body member  2050  on an end opposite the flanks  2062  and can extend radially outwardly therefrom. The head  2052  can be received in the arm aperture  2042  of a corresponding one of the arms  2028  and can be sized to non-rotatably but axially slidably engage the branches  2040  of the corresponding one of the arms  2028 . The second guide slots  2054  can be longitudinally extending grooves formed in the body member  2050  and the head  2052  that are sized to partly receive the guides  2006 . 
     The keeper  2004  can include a keeper head  2072  that can be received in the arm aperture  2042  of a corresponding one of the arms  2028  (opposite the arm  2028  that receives the head  2052  of the body member  2050 ) and can be sized to non-rotatably but axially slidably engage the branches  2040  of the corresponding one of the arms  2028 . The keeper head  2072  can extend radially outwardly from the body member  2050  of the cradle body  2002 . The keeper  2004  can be fixedly and non-rotatably coupled to the cradle body  2002  in any desired manner. In the particular example provided, the keeper  2004  includes a pair of keeper flanges  2064  that abut the flanks  2062  on the body member  2050  and a fastener, such as a pin (not specifically shown), is inserted through the keeper flanges  2064  and the flanges  2062  to couple the keeper  2004  to the cradle body  2002 . A pair of third guide slots  2066  can be formed in the keeper head  2072 . The third guide slots  2066  can be disposed in-line with the second guide slots  2054  in the cradle body  2002  when the keeper  2004  and the cradle body  2002  are assembled together. Those of skill in the art will appreciate that while the keeper  2004  and the cradle body  2002  have been described as being two discrete components that are assembled to one another, the keeper  2004  and the cradle body  2002  could be integrally and unitarily formed in the alternative. 
     The guides  2006  are configured to guide the keeper  2004  and the cradle body  2002  as they move along the first axis  1076  relative to the cradle  2000 . In the example provided, two guides  2006  are provided and each guide  2006  is a steel rod that is received into a corresponding set of the first, second and third guide slots  2048 ,  2054  and  2066 . It will be appreciated that as the first guide slots  2048  do not extend completely through the branches  2040  of the arms  2028 , the guides  2006  are trapped between the arms  2028  while the cradle body  2002  and the keeper  2004  can slide on the guides  2006  so as to be capable of telescoping out of either end of the cradle  2000 . 
     The cradle spring  2008  can be mounted co-axially about the central body  2020  of the cradle body  2002  and can abut an inside surface of the head  2052  of the cradle body  2002  and an inside surface of the keeper head  2072  of the keeper  2004 . The cradle spring  2008  can center the cradle body  2002  and the keeper  2004  relative to the arms  2028  of the cradle  2000 . Additionally, the cradle spring  2008  can permit axial movement of the cradle body  2002  along the first axis  1076  relative to the cradle  2000  as will be described in more detail, below. 
     The range fork  220  can include a first fork member  2100 , a first fork yoke  2102 , a second fork yoke  2104 , a first fork drive lug  2106  and a second fork drive lug  2108 . The first fork member  2100  can comprise a semi-circular structure having a groove  2120  into which the collar member  216  ( FIG. 4 ) is received. The first and second fork yokes  2102  and  2104  can be slidably engaged to the first rail  1010  and can be fixedly coupled to the first fork member  2100 . In the particular example provided, the first and third cradle yokes  2022  and  2026  are disposed axially between the first and second fork yokes  2102  and  2104 . The first fork drive lug  2106  can be coupled to the second fork yoke  2104  and can be positioned in-line with the first cradle drive lug  2030  such that the first cradle drive lug  2030  can contact the first fork drive lug  2106  in some situations to coordinate movement of the range fork  220 . The second fork drive lug  2108  can be coupled to the first fork yoke  2102  and can be positioned in-line with the second cradle drive lug  2032  such that the second cradle drive lug  2032  can contact the second fork drive lug  2108  in some situations to coordinate movement of the range fork  220 . 
     The mode fork  330  can include a second fork member  2200 , a third fork yoke  2202 , and a fourth fork yoke  2204 . The second fork member  2200  can comprise a semi-circular structure having a groove  2220  into which the collar member  326  ( FIG. 4 ) is received. The third and fourth fork yokes  2202  and  2204  can be slidably engaged to the second rail  1012  and can be fixedly coupled to the second fork member  2200 . In the particular example provided, the second cradle yoke  2024  is disposed axially between the third and fourth fork yokes  2202  and  2204 . 
     The first arm spring  1016  can be a compression spring that can be received on the first rail  1010  between the first fork yoke  2102  and the first cradle yoke  2022 . Accordingly, the first arm spring  1016  can bias the first fork yoke  2102  (and thereby the range fork  216 ) axially along the first rail  1010  in a direction away from the cradle  2000 . The second arm spring  1018  can be a compression spring that can be received on the second rail between second cradle yoke  2024  and the fourth fork yoke  2204 . Accordingly, the second arm spring  1018  can bias the fourth fork yoke  2204  (and thereby the mode fork  330 ) axially along the second rail  1012  in a direction away from the cradle  2000 . 
     With reference to  FIGS. 10 and 13 , the control system  1020  can comprise a controller  2300 , a rotary sensor  2302 , a first position sensor  2304  and a second position sensor  2306 . The controller  2300  can be coupled to a vehicle controller  2300 , a source of electrical power  2312  and the motor  1002 . The controller  2300  and the vehicle controller  2300  can communicate with one another to transmit vehicle data, a desired range setting and a desired mode setting from the vehicle controller  2300  to the controller  2300 , and to transmit operational data from the controller  2300  to the vehicle controller  2300 . The controller  2300  can selectively couple the motor  1002  to the source of electrical power  2312  to control the rotational direction of the motor  1002  and the extent to which the motor  1002  operates. 
     The rotary sensor  2302  can be coupled to the actuator housing  1000  and can be configured to sense rotation of a component within the actuator A and responsively generate a rotary sensor signal. In the particular example provided, the rotary sensor  2302  comprises a sensor pinion  2320 , which is driven by a first one of the intermediate spur gears  1058 , a magnetic pulse wheel  2322 , which is coupled to the sensor pinion  2320  for rotation therewith, and a Hall-effect sensor  2324  that is configured to sense rotation of the magnetic pulse wheel  2322  and generate a rotary sensor signal in response thereto. 
     The first position sensor  2304  can comprise a first sensor target  2330  and a first sensor  2332 . The first sensor target  2330  can comprise a first magnet that can be fixedly coupled to the range fork  220  for movement therewith along the first rail  1010 . In the example provided, the first sensor target  2330  is fixedly mounted to the second fork yoke  2104 . The first sensor  2332  can be any type of sensor that can sense a position of the first sensor target  2330  and responsively produce a first position signal. For example, the first sensor  2332  can comprise a plurality of Hall-effect sensors  2336  that are configured to sense the first sensor target  2330  and responsively produce respective position signals. 
     In the particular example provided, the first sensor  2332  comprises five Hall-effect sensors  2336  that are fixedly coupled to a circuit board  2338  of the controller  2300  and which are disposed along a first sensor axis  2340  that can be generally parallel to the second axis  1090 . The five Hall-effect sensors  2336  cooperate with the first sensor target  2330  to permit the movement of the range fork  220  along the second axis  1090  to be monitored and reported so that the controller  2300  can identify at least three predetermined positions of the range fork  220 , such as a high-speed position, a neutral speed position, and a low-speed position, and optionally a first intermediate position, in which the range fork  220  is disposed in between the high-speed and neutral speed positions, and a second intermediate position, in which the range fork  220  is disposed in between the neutral speed and low-speed positions. 
     The second position sensor  2306  can comprise a second sensor target  2350  and a second sensor  2352 . The second sensor target  2350  can comprise a second magnet that can be fixedly coupled to the mode fork  330  for movement therewith along the second rail  1012 . In the example provided, the second sensor target  2350  is fixedly mounted to the fourth fork yoke  2204 . The second sensor  2352  can be any type of sensor that can sense a position of the second sensor target  2350  and responsively produce a second position signal. For example, the second sensor  2352  can comprise a plurality of Hall-effect sensors  2356  that are configured to sense the second sensor target  2350  and responsively produce respective position signals. 
     In the particular example provided, the second sensor  2352  comprises three Hall-effect sensors  2356  that are fixedly coupled to the circuit board  2338  of the controller  2300  and which are disposed along a second sensor axis  2360  that can be generally parallel to the third axis  1092 . The three Hall-effect sensors  2356  cooperate with the second sensor target  2350  to permit the movement of the mode fork  330  along the third axis  1092  to be monitored and reported so that the controller  2300  can identify at least two predetermined positions of the mode fork  330 , such as a two-wheel drive position and a four-wheel drive position, and optionally a third intermediate position between the two-wheel and four-wheel drive positions. 
     In operation, the controller  2300  can operate the motor  1002  to drive the cradle assembly  1014  (via the lead screw  1008 ) to coordinate movement of the range fork  220  and the mode fork  330 . The rotary sensor  2302  can be employed by the controller  2300  to control the amount by which the motor  1002  rotates the lead screw  1008 , while the first and second position sensors  2304  and  2306  can be employed by the controller  2300  to identify the positioning of the range collar  180  and the mode collar  320  (or the range fork  220  and the mode fork  330 ). 
     When the power transmitting component is operated in the two-wheel drive, high range ( FIG. 6 ), the cradle assembly  1014  can be positioned in a first cradle position along the first axis  1076  such that the first arm spring  1016  is compressed between the first arm yoke—and the first fork yoke  2102  and the range fork  220  is abutted against the edge of the fork window  1050  (i.e., the range fork  220  is in the high-speed position), while the second arm spring  1018  biases the mode fork  330  in a direction such that the third fork arm  2028  abuts the second cradle arm  2028  to thereby position the mode fork  330  in the two-wheel drive position. 
     If a change in the manner that the power transmitting component operates is desired, the lead screw  1008  can be rotated in a first rotational direction to drive the cradle assembly  1014  along the first axis  1076  in a first axial direction. Assuming that the mode collar  320  moves along the input member axis  92  with movement of the cradle assembly  1014  along the first axis  1076 , the mode fork  330  can be moved from the two-wheel drive position, to the third intermediate position and thereafter into the four-wheel drive position. In the event that the mode collar  320  is not able to move into the four-wheel drive position (e.g., the second (internal) set of mode teeth  322  is not aligned to the mode teeth  270  on the PTU input member  32 ), the second arm spring  1018  can provide sufficient compliance to permit the cradle assembly  1014  to be fully moved by the lead screw  1008  despite the cessation of movement of the mode fork  330 , as well as apply a biasing force (directed axially along the second rail  1012 ) to the fourth fork yoke  2204  that will cause the mode fork  330  to move along the second rail into the four-wheel drive position when the second (internal) set of mode teeth  322  is aligned to and engageable with the mode teeth  270  on the PTU input member  32 . 
     If a further change in the manner that the power transmitting component operates is desired, the lead screw  1008  can be rotated in a first rotational direction to further drive the cradle assembly  1014  along the first axis  1076 . Assuming that the range collar  180  moves along the input member axis  92  with movement of the cradle assembly  1014  along the first axis  1076 , the range fork  220  can be moved from the high-speed position, to the neutral speed position and thereafter into the low-speed position. In the event that the range collar  180  is not able to move into the low-speed position (e.g., the sixth set of (internal) range teeth  214  is not aligned to the second set of (external) range teeth  192  on the input shaft  170 ), the cradle spring  2008 , through its compression between the head  2052  of the cradle body  2002  and the opposite arm  2028  of the cradle  2000 ) can provide sufficient compliance to permit the cradle assembly  1014  to be fully moved by the lead screw  1008  despite the cessation of movement of the range fork  220 . Moreover, because the first cradle drive lug  2030  contacts the first fork drive lug  2106  as the cradle  2000  drives the range fork  220  into the low-speed position, compression of the cradle spring  2008  applies a biasing force (directed axially along the first axis  1076 ) to the cradle  2000  that will cause the cradle  2000  to move the range fork  220  into the low-speed position when the sixth set of (internal) range teeth  214  is aligned to and engageable with the second set of (external) range teeth  192  on the input shaft  170 . 
     When the user desires to shift the power transmitting component out of the low-speed, four-wheel drive mode, the lead screw  1008  can be rotated in a second rotational direction (opposite the first rotational direction) to move the cradle assembly  1014  along the first axis  1076  in a second axial direction that is opposite the first axial direction. Assuming that the range collar  180  moves along the input member axis  92  with movement of the cradle assembly  1014  along the first axis  1076 , the range fork  220  can be moved from the low-speed position to the neutral speed position and thereafter into the high-speed position. 
     In the event that the range collar  180  is not able to move into the high-speed position (e.g., the range collar  180  is torque-locked to the input shaft  170 ), first arm spring  1016  can be compressed to permit the second cradle drive lug  2032  to contact the second fork drive lug  2108 . Further rotation of the lead screw  1008  in the second rotational direction can move the cradle body  2002  in the second axial direction relative to the cradle  2000  to cause compression of the cradle spring  2008 . The compression of the cradle spring  2008  provides a degree of compliance that permits the cradle body  2002  to be fully moved by the lead screw  1008  without corresponding motion of the cradle  2000  or the range fork  220 . Compression of the cradle spring  2008  can maintains a force on the cradle  2000  that is transmitted through the second cradle drive lug  2032  and the second fork drive lug  2108  that tends to urge both the cradle  2000  and the range fork  220  in the second axial direction and away from the mode fork  330 . Additionally, the first arm spring  1016  is compressed in this state and applies a biasing force to the range fork  220  to urge the range fork  220  toward the high-speed position. 
     When the user desires to shift the power transmitting component out of the high-speed, four-wheel drive mode and into the high-speed, two-wheel drive mode, the lead screw  1008  can be further rotated in the second rotational direction to further move the cradle assembly  1014  along the first axis  1076  in the second axial direction. Assuming that the mode collar  3200  moves along the input member axis  92  with movement of the cradle assembly  1014  along the first axis  1076 , the mode fork  330  can be moved from the four-wheel drive position to the third intermediate position and thereafter into the two-wheel drive position. 
     In the event that the mode collar  320  is not able to move into the two-wheel drive position (e.g., the mode collar  320  is torque-locked to the PTU input member  32 ), the lead screw  1008  can be driven in the second rotational direction to move the cradle body  2002  in the second axial direction relative to the cradle  2000  to cause compression of the second arm spring  1018  and optionally the cradle spring  2008 . The compression of the second arm spring  1018  (and optionally the cradle spring  2008 ) provides a degree of compliance that permits the cradle body  2002  to be fully moved by the lead screw  1008  without corresponding motion of the cradle  2000  or the mode fork  330 . Compression of the cradle spring  2008  can maintains a force on the cradle  2000  that is transmitted through the second cradle yoke  2024  to the third fork yoke  2202  that tends to urge both the cradle  2000  and the mode fork  330  in the second axial direction toward the range fork  220 . 
     The controller  2300  can be configured to limit (or coordinate the limitation of) power transmitted through the power transmitting component in the event that the range collar  180  is only engaged to either the input shaft  170  or to the planet carrier  176  to a predetermined extent (i.e., an extent that is less than fully engaged), or if the mode collar  320  is only engaged to the PTU input member  32  to a predetermined extend (i.e., an extent that is less than fully engaged). More specifically, the controller  2300  can be configured to perform the following method: translating the collar (e.g., the range collar  180  or the mode collar  320 ) to a fully disengaged position (e.g., a neutral position); generating a command to move the clutch fork (e.g., the range fork  220  or the mode fork  330 ) to an engaged position (e.g., the low-speed position or the high-speed position for the range fork  220  or the four-wheel drive position for the mode fork  330 ) and responsively operating the electric motor (e.g., motor  1002 ) to cause the clutch fork to move the collar toward the fully engaged position; determining a position of the collar along the axis (e.g., input member axis  92 ) after the electric motor has halted operation; and limiting rotary power transmitted through the collar if the collar is not located in the fully engaged but is nevertheless engaged to the second power transmitting member to at least a predetermined extent. Additionally, the method could inhibit transmission of rotary power through the collar if the collar is not in the fully disengaged position and the collar is engaged to the second power transmitting member to an extent that is less than the predetermined extent. 
     It will be appreciated that one or more locking devices can be integrated into the actuator A to lock the range fork  220  and/or the mode fork  330  in a desired position. In the example of  FIG. 17 , a detent mechanism D is incorporated into each of the range fork  220 ′ and the mode fork (not specifically shown). The detent mechanism comprises a plunger  3000 , a plunger spring  3002 , and a detent ball  3004  that is mounted in a detent aperture  3006  formed in the range fork  220 ′. The plunger  3000  is mounted to the range fork  220 ′ generally parallel to the first rail  1010 ′. The plunger  3000  includes a first ball groove  3010  that is configured to be complementary to the detent ball  3004 . The plunger spring  3002  is mounted coaxially about the plunger  3000  and is configured to bias the plunger  3000  such that the first ball groove  3010  is not in-line with the detent ball  3004 . When the range fork  220 ′ is moved into a desired position, the detent aperture  3006  is aligned to a second ball groove  3020  formed in the first rail  1010 ′, which permits the plunger spring  3002  to move the plunger  3000  such that the detent ball  3004  is moved into the second ball groove  3020 . In this condition, the detent ball  3004  is not disposed in the first ball groove  3010  and as such, the plunger  3000  prevents the detent ball  3004  from being withdrawn (into the detent aperture  3006  in the range fork  220 ′) by an amount that permits the detent ball  3004  to disengage the first rail  1010 ′. Accordingly, the range yoke  220 ′ is locked in the desired position. To unlock the range yoke  220 ′, another structure, such as the cradle (not shown), the actuator housing (not shown) or the mode fork (not shown) can be employed to press on the plunger  3000  to move the plunger  3000  relative to the range fork  220 ′ to align the detent ball  3004  to the first ball groove  3010 . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.