초록 ▼

A transfer case having an input shaft driven by a powertrain, a first output shaft adapted for connection to a first driveline, a second output shaft adapted for connection to a second driveline, an interaxle differential operably disposed between the input shaft and the first and second output shaf

A transfer case having an input shaft driven by a powertrain, a first output shaft adapted for connection to a first driveline, a second output shaft adapted for connection to a second driveline, an interaxle differential operably disposed between the input shaft and the first and second output shafts, and a torque transfer mechanism. The torque transfer mechanism includes a friction clutch assembly operably disposed between the first output shaft and the second output shaft, and a clutch actuator assembly for generating and applying a clutch engagement force to the friction clutch assembly. The clutch actuator assembly includes an electric motor, a geared reduction unit, and a clutch apply operator. A control system including vehicle sensors and a controller are provided to control actuation of the electric motor.

대표청구항 ▼

What is claimed is: 1. A transfer case for use in a motor vehicle having a powertrain and first and second drivelines, comprising: an input shaft driven by the powertrain; a reduction unit driven by said input shaft; a first output member adapted to drive the first driveline; a second output membe

What is claimed is: 1. A transfer case for use in a motor vehicle having a powertrain and first and second drivelines, comprising: an input shaft driven by the powertrain; a reduction unit driven by said input shaft; a first output member adapted to drive the first driveline; a second output member adapted to drive the second driveline; a first clutch operable in a first range position for establishing a high-range drive connection between said reduction unit and said first output member and in a second range position for establishing a low-range drive connection between said reduction unit and said first output member; a second clutch for transmitting drive torque from said first output member to said second output member; an electric motor for rotating a driveshaft; and a clutch operator having a first member driven by said driveshaft, a second member axially moveable between first and second mode positions for controlling the magnitude of a clutch engagement force applied to said second clutch, and a third member for converting rotary movement of said first member into axial movement of said second member, said third member including a lost motion mechanism configured to permit rotary movement of said first member relative to said third member to coordinate movement of said second member between its first and second mode positions with movement of said first clutch between its first and second range positions in response to rotation of said driveshaft. 2. The transfer case of claim 1 wherein said first clutch includes a range sleeve that is axially moveable between said first and second range positions and a range shift mechanism operable to convert rotary movement of said driveshaft into axial translation of said range sleeve. 3. The transfer case of claim 2 wherein said range shift mechanism includes a cam fixed to said driveshaft, a range fork engaging said range sleeve and a follower operably disposed between said cam and said range fork. 4. The transfer case of claim 1 wherein said lost motion mechanism includes a slot formed in said first member of said clutch operator and a follower fixed to said third member which extends into said slot so as to permit relative rotation therebetween. 5. The transfer case of claim 4 wherein said first member of said clutch operator has a gear segment driven by said driveshaft, said second member of said clutch operator has a cam segment, and said third member has a drive segment engaging said cam segment. 6. The transfer case of claim 5 wherein rotation of said driveshaft in a first direction causes said first clutch to move to its first range position while said first member of said clutch operator is rotated in a first direction to cause said follower to engage a first end of said slot such that said drive segment of said third member engages a portion of said cam segment on said second member so as to locate said second member in its first mode position for applying a minimum clutch engagement force on said second clutch. 7. The transfer case of claim 6 wherein continued rotation of said driveshaft in said first direction causes said first clutch to remain in its first range position while engagement of said follower with said first end of said slot causes concurrent rotation of said third member with said first member, whereby such rotation of said third member causes its drive segment to engage said cam segment of said second member so as to move said second member from its first mode position toward its second mode position so as to increase the clutch engagement force applied to said second clutch. 8. A transfer case for use in a motor vehicle having a powertrain and first and second drivelines, comprising: a reduction unit driven by the powertrain; a first output member adapted to drive the first driveline; a second output member adapted to drive the second driveline; a range clutch operable in a first range position for establishing a high-range drive connection between said reduction unit and said first output member and in a second range position for establishing a low-range drive connection between said reduction unit and said first output member; a friction clutch operably disposed between said first and second output members; an electric motor for driving a driveshaft; and a clutch operator having a first member driven by said driveshaft, a second member axially moveable between first and second mode positions for releasing and engaging said friction clutch, and a third member for converting rotary movement of said first member into axial movement of said second member, said third member including a movement coordinating mechanism configured to permit relative rotation between said first and third members so as to coordinate movement of said second member between its first and second mode positions with movement of said range clutch between its first and second range positions in response to rotation of said driveshaft. 9. The transfer case of claim 8 wherein said range clutch includes a range sleeve that is axially moveable between said first and second range positions and a range shift mechanism operable to convert rotary movement of said driveshaft into axial translation of said range sleeve. 10. The transfer case of claim 8 wherein said movement coordinating mechanism includes a slot formed in one of said first and third members of said clutch operator and a follower fixed to the other of said first and third members, said follower extending into said slot so as to permit relative rotation between said first and third members. 11. The transfer case of claim 10 wherein said first member of said clutch operator has a gear segment driven by said driveshaft, said second member of said clutch operator has a cam segment, and said third member has a drive segment engaging said cam segment. 12. The transfer case of claim 11 wherein rotation of said driveshaft in a first direction causes said range clutch to move to its first range position while said first member of said clutch operator is rotated in a first direction to cause said follower to engage a first end of said slot such that said drive segment of said third member engages a portion of said cam segment on said second member so as to locate said second member in its first mode position for applying a minimum clutch engagement force to said friction clutch, and wherein continued rotation of said driveshaft in said first direction causes said first clutch to remain in its first range position while engagement of said follower with said first end of said slot causes concurrent rotation of said third member with said first member, whereby such rotation of said third member causes its drive segment to engage said cam segment of said second member so as to move said second member from its first mode position toward its second mode position so as to increase the clutch engagement force applied to said second clutch. 13. A transfer case for use in a motor vehicle having a powertrain and first and second drivelines, comprising: an input shaft driven by the powertrain; a reduction unit driven by said input shaft; a first output shaft adapted to drive the first driveline; a second output shaft adapted to drive the second driveline; a range clutch operable in a first range position for establishing a high-range drive connection between said first output shaft and said reduction unit and in a second range position for establishing a low-range drive connection between said first output shaft and said reduction unit; a friction clutch for transmitting drive torque between said first output shaft and said second output shaft; an electric motor driving a driveshaft; a range shift mechanism for moving said range clutch between its first and second range position in response to rotation of said driveshaft; a clutch operator adapted to generate and apply a clutch engagement force to said friction clutch, said clutch operator having a first cam member and a second cam member that is axially moveable between first and second mode positions in response to relative rotation between said first and second cam members; a gearset having a first gear driven by said driveshaft and a second gear driven by said first gear; and a conversion mechanism for converting rotation of said gearset into axial movement of said second cam member, said conversion mechanism including a lost motion arrangement configured to permit rotation of said second gear relative to said first cam member for coordinating movement of said second cam member between its first and second mode positions with movement of said range clutch between its first and second range positions. 14. The transfer case of claim 13 wherein said lost motion arrangement includes a slot formed in said second gear and a follower fixed to said first cam member, and wherein said follower extends into said slot so as to permit limited relative rotation between said second gear of said gearset and said first cam member. 15. The transfer case of claim 14 wherein rotation of said driveshaft in a first rotary direction causes said range shift mechanism to move said range clutch to its first range position while said second gear is rotated in a first rotary direction until said follower engages a first end of said slot such that said second cam member is located in its first mode position for applying a minimum clutch engagement force to said friction clutch. 16. The transfer case of claim 15 wherein continued rotation of said driveshaft in its first rotary direction causes said range shift mechanism to maintain said range clutch in its first range position while engagement of said follower with said first end of said slot causes said first cam member to rotate relative to said second cam member thereby causing said second cam member to move toward its second mode position so as to increase the clutch engagement force applied to said friction clutch. 17. The transfer case of claim 16 wherein said second cam member includes a cam surface and said first cam member includes a cam roller engaging said cam surface. 18. A transfer case for use in a motor vehicle having a powertrain and first and second drivelines, comprising: an input shaft driven by the powertrain; a reduction unit having an input member driven by said input shaft and an output member; a first output shaft adapted to drive the first driveline; a second output shaft adapted to drive the second driveline; an interaxle differential having an input driven by said output member of said reduction unit and first and second outputs respectively connected to said first and second output shafts; a range clutch operable in a first range position for establishing a high-range drive connection between said input shaft and said input of said interaxle differential and in a second range position for establishing a low-range drive connection between said input shaft and said input of said interaxle differential; a mode clutch operably disposed between said first output shaft and said second output shaft; an electric motor for rotating a driveshaft; and a clutch operator having a first member driven by said driveshaft, a second member axially moveable between first and second mode positions for controlling the magnitude of a clutch engagement force applied to said mode clutch, and a third member for converting rotary movement of said first member into axial movement of said second member, said third member having a lost motion mechanism configured to permit limited relative rotation between said first and third members for coordinating movement of said second member between its first and second mode positions with movement of said range clutch between its first and second range positions in response to rotation of said driveshaft. 19. The transfer case of claim 18 wherein said lost motion mechanism includes a slot formed in one of said first and third members of said clutch operator and a follower fixed to the other of said first and third members which extends into said slot so as to permit relative rotation therebetween. 20. The transfer case of claim 19 wherein said first member of said clutch operator has a gear segment driven by said driveshaft, said second member of said clutch operator has a cam segment and said third member has a drive segment engaging said cam segment. 21. The transfer case of claim 20 wherein rotation of said driveshaft in a first direction causes said range clutch to move to its first range position while said first member of said clutch operator is rotated in a first direction to cause said follower to engage a first end of said slot such that said drive segment of said third member engages a portion of said cam segment on said second member so as to locate said second member in its first mode position for applying a minimum clutch engagement force on said mode clutch, and wherein continued rotation of said driveshaft in said first direction causes said range clutch to remain in its first range position while engagement of said follower with said first end of said slot causes concurrent rotation of said third member with said first member, whereby such rotation of said third member causes its drive segment to engage said cam segment of said second member so as to move said second member from its first mode position toward its second mode position so as to increase the clutch engagement force applied to said mode clutch.