초록 ▼

A controllable, multi-mode, bi-directional overrunning mode clutch and a shift system adapted for use in a power transfer assembly for transferring drive torque from a primary driveline to a secondary driveline so as to establish a four-wheel drive mode. The mode clutch includes a first ring journal

A controllable, multi-mode, bi-directional overrunning mode clutch and a shift system adapted for use in a power transfer assembly for transferring drive torque from a primary driveline to a secondary driveline so as to establish a four-wheel drive mode. The mode clutch includes a first ring journalled on a first rotary member, a second ring fixed to a second rotary member, and a plurality of rollers disposed in opposed cam tracks formed between the first and second rings. The first ring is split to define an actuation channel between its end segments. A cam member is moveable between positions engaged with and released from one or both end segments of the split first ring. The shift system includes a mode fork which controls movement of the cam member for establishing a two-wheel drive mode in addition to on-demand and locked four-wheel drive modes.

대표청구항 ▼

What is claimed is: 1. A power transfer device for use in a motor vehicle having a powertrain and first and second drivelines, comprising: a first output interconnecting the powertrain to the first driveline; a second output connected to the second driveline; an overrunning mode clutch operably dis

What is claimed is: 1. A power transfer device for use in a motor vehicle having a powertrain and first and second drivelines, comprising: a first output interconnecting the powertrain to the first driveline; a second output connected to the second driveline; an overrunning mode clutch operably disposed between said first and second outputs, said mode clutch is operable in a first mode to permit relative rotation between said first and second outputs in a first direction and prevent relative rotation therebetween in a second direction, said mode clutch is operable in a second mode to prevent relative rotation between said first and second outputs in both directions, and said mode clutch is operable in a third mode to permit relative rotation between said first and second output in both directions, said mode clutch including a first ring driven by one of said first and second outputs, a second ring operably disposed between said first ring and the other of said first and second outputs and having an actuation slot, rollers engaging a cam surface formed between said first and second rings and an actuator ring having a lug retained in said actuation slot, said actuator ring is operable in a first actuator position to permit movement of said lug into engagement with one of first and second end surfaces of said actuation slot, and said actuator ring is operable in a second actuator position to locate said lug in engagement with both of said first and second end surfaces of said actuator slot; a mode shift mechanism operable in a first mode position to shift said mode clutch into its first mode, in a second mode position to shift said mode clutch into its second mode and in a third mode position to shift said mode clutch into its third mode; and a shift system for moving said mode shift mechanism between its first, second and third mode positions. 2. The power transfer device of claim 1 wherein said mode shift mechanism is operable in its first mode position to cause a drag member to exert a drag force on said actuator ring in its first actuator position, wherein said mode shift mechanism is operable in its second mode position to cause said drag member to release said drag force from said actuator ring in its first actuator position, and wherein said mode shift mechanism is operable in its third mode position to release said drag force while causing movement of said actuator ring from its first actuator position to its second actuator position. 3. The power transfer device of claim 1 wherein said shift system includes an electric motor having a rotary output and a drive mechanism for converting bi-directional rotary motion of said motor output into bi-directional translational motion of said mode shift mechanism between its three distinct mode positions. 4. The power transfer device of claim 3 further comprising: a control system having a mode selector capable of generating a mode signal indicative of the mode selected; and a control unit receiving said mode signal and actuating said motor in response thereto for moving said mode shift mechanism to its mode position corresponding to the selected mode. 5. The power transfer device of claim 1 defining a transfer case with a first output shaft as its first output and a second output shaft as its second output, and further including a transfer unit driven by said first output shaft with said mode clutch operably disposed between said transfer unit and said second output shaft. 6. The power transfer device of claim 1 defining a power take-off unit having a right-angled drive unit as its first output and a transfer shaft driving a differential associated with the second driveline as its second output, and wherein said mode clutch is operably disposed between said drive unit and said transfer shaft. 7. The power transfer device of claim 1 defining a power take-off unit having differential carrier of a differential unit associated with the first driveline as its first output and a right-angled drive unit as its second output, and wherein said mode clutch is operably disposed between said differential carrier and said drive unit. 8. The power transfer device of claim 1 defining a power take-off unit having a first differential unit, a drive unit as its first output and a second differential unit as its second output, said first differential unit including an input member driven by the powertrain, a first output gear driving said drive unit and a second output gear driving said second differential unit, and wherein said mode clutch is operably disposed between said first and second output gears of said first differential unit. 9. A transfer case for use in a four-wheel drive motor vehicle having a powertrain and first and second drivelines, comprising: a first shaft for transmitting drive torque from the powertrain to the first driveline; a second shaft for transmitting drive torque to the second driveline; a transfer unit driving said second output shaft; a bi-directional overrunning mode clutch operable for transmitting drive torque from said first shaft to said transfer unit, said mode clutch including a first ring coupled for rotation with said first shaft and having first cam tracks, a second ring disposed between said first ring and said transfer unit and having second cam tracks, rollers disposed within aligned pairs of said first and second cam tracks, and an actuator ring supported for translational movement between a first actuator position and a second actuator position, said actuator ring having a lug disposed within an actuation slot formed in said second ring; a mode shift mechanism moveable between first, second and third mode positions, said mode shift mechanism is operable in its first mode position to locate said actuator ring in its first actuator position and permit movement of said lug from a central position into engagement with one of first and second end surfaces of said actuation slot so as to establish an on-demand four-wheel drive mode, said mode shift mechanism is operable in its second mode position to locate said actuator ring in its first actuator position and inhibit movement of said lug into engagement with either of said first and second end surfaces of said actuation slot so as to establish a locked four-wheel drive mode, and wherein said mode shift mechanism is operable in its third mode position to locate said actuator ring in its second actuator position and position said lug in engagement with both of said end surfaces of said actuation slot so as to establish a two-wheel drive mode, and a shift system for moving said mode shift mechanism between its three distinct mode positions. 10. The transfer case of claim 9 wherein said shift system comprises: a drive mechanism coupled to said mode shift mechanism; a power-operated actuator for causing said drive mechanism to move said mode shift mechanism; a mode selector for permitting selection of at least said on-demand four-wheel drive mode and said locked four-wheel drive mode and generating a mode signal indicative of the drive mode selected; and a control unit for receiving said mode signal and controlling actuation of said power-operated actuator for moving said mode shift mechanism to its first mode position when said on-demand four-wheel drive mode is selected and moving said mode shift mechanism to its second mode position when said locked four-wheel drive mode is selected. 11. The transfer case of claim 10 wherein said mode selector further permits selection of said two-wheel drive mode which causes said control unit to command said power-operated actuator to move said mode shift mechanism to its third mode position. 12. The transfer case of claim 10 wherein said control unit is further operable to cause said mode select mechanism to be moved from either of its first or second mode positions into its third mode position in response to detection of a braking condition. 13. The transfer case of claim 9 further comprising: a third shaft driven by the powertrain; and a center differential having an input driven by said third shaft, a first output connected to said first shaft and a second output connected to said transfer unit. 14. A transfer case for use in a four-wheel drive motor vehicle having a powertrain and first and second drivelines, comprising: a first shaft for transmitting drive torque from the powertrain to the first driveline; a second shaft for transmitting drive torque to the second driveline; a transfer unit driven by said first shaft; a bi-directional overrunning mode clutch operable for transmitting drive torque from said transfer unit to said second shaft, said mode clutch including a first ring coupled for rotation with said second shaft and having first cam tracks, a second ring disposed between said first ring and said transfer unit and having second cam tracks, rollers disposed within aligned pairs of said first and second cam tracks, and an actuator ring supported for translational movement between a first actuator position and a second actuator position, said actuator ring having a lug disposed within an actuation slot formed in said second ring; a mode shift mechanism moveable between first, second and third mode positions, said mode shift mechanism is operable in its first mode position to locate said actuator ring in its first actuator position and permit movement of said lug from a central position into engagement with one of first and second end surfaces of said actuation slot so as to establish an on-demand four-wheel drive mode, said mode shift mechanism is operable in its second mode position to locate said actuator ring in its first actuator position and inhibit movement of said lug into engagement with either of said first and second end surfaces of said actuation slot so as to establish a locked four-wheel drive mode, and wherein said mode shift mechanism is operable in its third mode position to locate said actuator ring in its second actuator position and position said lug in engagement with both of said end surfaces of said slot so as to establish a two-wheel drive mode; and a shift system for moving said mode shift mechanism between its three distinct mode positions. 15. The transfer case of claim 14 wherein said shift system comprises: a drive mechanism coupled to said mode shift mechanism; a power-operated actuator for causing said drive mechanism to move said mode shift mechanism; a mode selector for permitting selection of at least said on-demand four-wheel drive mode and said locked four-wheel drive mode and generating a mode signal indicative of the drive mode selected; and a control unit for receiving said mode signal and controlling actuation of said power-operated actuator for moving said mode shift mechanism to its first mode position when said on-demand four-wheel drive mode is selected and moving said mode shift mechanism to its second mode position when said locked four-wheel drive mode is selected. 16. The transfer case of claim 15 wherein said mode selector further permits selection of said two-wheel drive mode which causes said control unit to command said power-operated actuator to move said mode shift mechanism to its third mode position. 17. In a four-wheel drive vehicle having a powertrain and first and second sets of wheels, a power transfer unit comprising: a first drive mechanism having a first rotary component for transmitting drive torque from the powertrain to a first driveline for driving the first set of wheels; a second drive mechanism having a second rotary component for transmitting drive torque to the second pair of wheels; a bi-directional overrunning mode clutch operable for transmitting drive torque from said first drive mechanism to said second drive mechanism, said mode clutch includes a first ring fixed for rotation with said first rotary component of said first drive mechanism and having first cam tracks, a second ring disposed between said first ring and said second rotary component of said second drive mechanism and having second cam tracks, rollers disposed within aligned pairs of said first and second cam tracks and an actuator ring supported for translational movement between a first actuator position and a second actuator position and having a lug disposed within an actuation slot formed in said second ring; a mode shift mechanism moveable between first, second and third mode positions, said mode shift mechanism is operable in its first mode position to locate said actuator ring in its first actuator position and permit movement of said lug from a central position into engagement with one of first and second end surfaces of said actuation slot so as to establish an on-demand four-wheel drive mode, said mode shift mechanism is operable in its second mode position to locate said actuator ring in its first actuator position and inhibit movement of said lug into engagement with either of said first and second end surfaces of said actuation slot so as to establish a locked four-wheel drive mode, and wherein said mode shift mechanism is operable in its third mode position to locate said actuator ring in its second actuator position and position said lug in engagement with both of said end surfaces of said slot so as to establish a two-wheel drive mode, and a shift system for moving said mode shift mechanism between its three distinct mode positions. 18. The power transfer unit of claim 17 wherein said shift system comprises: a power-operated actuator for moving said mode shift mechanism; a mode selector for permitting selection of at least said on-demand four-wheel drive mode and said locked four-wheel drive mode and generating a mode signal indicative of the drive mode selected; and a control unit for receiving said mode signal and controlling actuation of said power-operated actuator for moving said mode shift mechanism to its first mode position when said on-demand four-wheel drive mode is selected and moving said mode shift mechanism to its second mode position when said locked four-wheel drive mode is selected. 19. The power transfer unit of claim 18 wherein said mode selector further permits selection of said two-wheel drive mode which causes said control unit to command said power-operated actuator to move said mode shift mechanism to its third mode position. 20. The power transfer unit of claim 18 wherein said control unit is further operable to cause said mode select mechanism to be moved from either of its first or second mode positions into its third mode position in response to detection of a braking condition. 21. A power take-off unit for use in a motor vehicle having a powertrain and first and second drivelines, comprising: a first shaft transmitting drive torque from the powertrain to the first driveline; a second shaft driving the second driveline; a bi-directional overrunning mode clutch operably disposed between said first and second shafts, said mode clutch is operable in a first mode to permit relative rotation between said first and second shafts in a first direction and prevent relative rotation therebetween in a second direction, said mode clutch is operable in a second mode to prevent relative rotation between said first and second shafts in both directions and said mode clutch is operable in a third mode to permit relative rotation between said first and second shafts in both directions; a mode shift mechanism operable in a first mode position to shift said mode clutch into its first mode, in a second mode position to shift said mode clutch into its second mode and in a third mode position to shift said mode clutch into its third mode; and a shift system for moving said mode shift mechanism to its first mode position to establish an on-demand four-wheel drive mode, to its second mode position to establish a locked four-wheel drive mode, and to its third mode position to establish a two-wheel drive mode. 22. A power transfer device for use in a motor vehicle having a powertrain and first and second drivelines, comprising: a first rotary member interconnecting the powertrain to the first driveline; a second rotary member connected to the second driveline; a mode clutch operably disposed between said first and second rotary members, said mode clutch is operable in a first mode to permit relative rotation between said first and second rotary members in a first direction and prevent relative rotation therebetween in a second direction, said mode clutch is operable in a second mode to prevent relative rotation between said first and second rotary members in both directions, and said mode clutch is operable in a third mode to permit relative rotation between said first and second rotary members in both directions, said mode clutch including a first ring driven by one of said first and second rotary members, a second ring operably disposed between said first ring and the other of said first and second rotary members, rollers engaging a cam surface formed between said first and second rings, and an actuator ring supported for axial movement relative to said second ring between first and second actuator positions; a mode shift member operable in a first mode position to shift said mode clutch into its first mode, in a second mode position to shift said mode clutch into its second mode and in a third mode position to shift said mode clutch into its third mode; and a shift system for moving said mode shift member between its first, second and third mode positions. 23. The power transfer device of claim 22 wherein a lug formed on said actuator ring is retained in an actuation slot formed in said second ring, wherein said actuator ring is operable in its first actuator position to permit movement of said lug into engagement with one of first and second end surfaces of said actuation slot, and wherein said actuator ring is operable in its second actuator position to locate said lug in engagement with both of said first and second end surfaces of said actuator slot. 24. The power transfer device of claim 23 wherein said mode shift member is operable in its first mode position to exert a drag force on said actuator ring in its first actuator position, wherein said mode shift member is operable in its second mode position to release said drag force from said actuator ring in its first actuator position, and wherein said mode shift member is operable in its third mode position to release said drag force while causing movement of said actuator ring from its first actuator position to its second actuator position. 25. The power transfer device of claim 23 wherein said shift system includes an electric motor having a rotary output and a drive mechanism for converting bi-directional rotary motion of said motor output into bi-directional translational motion of said mode shift member between its three distinct mode positions. 26. The power transfer device of claim 22 defining a transfer case with a first output shaft as its first rotary member and a second output shaft as its second rotary member, and further including a transfer unit driven by said first output shaft with said mode clutch operably disposed between said transfer unit and said second output shaft. 27. The power transfer device of claim 23 defining a transfer case with a first output shaft as its first rotary member and a second output shaft as its second rotary member, and further comprising a transfer unit driven by said second output shaft with said mode clutch operably disposed between said transfer unit and said first output shaft. 28. The power transfer device of claim 22 defining a power take-off unit having a right-angled drive unit as its first rotary member and a transfer shaft driving a differential associated with the second driveline as its second rotary member, and wherein said mode clutch is operably disposed between said drive unit and said transfer shaft. 29. The power transfer device of claim 22 defining a power take-off unit having differential carrier of a differential unit associated with the first driveline as its first rotary member and a right-angled drive unit as its second rotary member, and wherein said mode clutch is operably disposed between said differential carrier and said drive unit. 30. The power transfer device of claim 22 defining a power take-off unit having a first differential unit, a drive unit as its first rotary member and a second differential unit as its second rotary member, said first differential unit including an input member driven by the powertrain, a first output gear driving said drive unit and a second output gear driving said second differential unit, and wherein said mode clutch is operably disposed between said first and second output gears of said first differential unit. 31. A power transfer device for use in a motor vehicle having a powertrain and first and second drivelines, comprising: a differential having an input driven by the powertrain and first and second outputs; a first rotary member connecting said first output to the first driveline; a second rotary member connecting said second output to the second driveline; a mode clutch operable in a first mode to permit relative rotation between said first and second rotary members in a first direction and prevent relative rotation therebetween in a second direction to establish an automatic four-wheel drive connection between the powertrain and said first and second rotary members, said mode clutch is operable in a second mode to prevent relative rotation between said first and second rotary members in both directions to establish a locked four-wheel drive connection between the powertrain and said first and second rotary members, and said mode clutch is operable in a third mode to permit relative rotation between said first and second rotary members in both directions to establish an open four-wheel drive connection between the powertrain and said first and second rotary members; and a mode shift mechanism operable in a first mode position to shift said mode clutch into its first mode, in a second position to shift said mode clutch into its second mode, and in a third mode position to shift said mode clutch into its third mode.