초록 ▼

A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes a power-operated face gear clutch actuator f

A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes a power-operated face gear clutch actuator for generating and applying a clutch engagement force on the clutch assembly.

대표청구항 ▼

What is claimed is: 1. A power transmission device comprising: a rotary input member adapted to receive drive torque from a power source; a rotary output member adapted to provide drive torque to an output device; a torque transfer mechanism operable for transferring drive torque from said input me

What is claimed is: 1. A power transmission device comprising: a rotary input member adapted to receive drive torque from a power source; a rotary output member adapted to provide drive torque to an output device; a torque transfer mechanism operable for transferring drive torque from said input member to said output member, said torque transfer mechanism including a clutch assembly operably disposed between said input member and said output member and a clutch actuator assembly for applying a clutch engagement force to said clutch assembly, said clutch actuator assembly including an electric motor driving a geared drive unit for controlling said clutch engagement force applied to said clutch assembly by a clutch apply operator, said geared drive unit includes a drive gear driven by said electric motor and first and second face gears with said drive gear in meshed engagement therebetween so as to cause said first and second face gears to rotate in opposite directions in response to driven rotation of said drive gear, said clutch apply operator including a first cam plate fixed for rotation with said first face gear, a second cam plate fixed for rotation with said second face gear and rollers disposed between said first and second cam plates; and a control system for actuating said electric motor so as to control the direction and amount of opposite rotary movement between said first and second face gears which, in turn, controls the direction and amount of translational movement of said first cam plate relative to said clutch assembly so as to vary the clutch engagement force exerted on said clutch assembly. 2. The power transmission device of claim 1 wherein said first face gear includes a first hub segment rotatably supported on said input member and a first ring segment having first gear teeth formed on a first face surface, wherein said second face gear includes a second hub segment rotatably supported on said first hub segment and a second ring segment having second gear teeth formed on a second face surface, and wherein said drive gear is meshed with said first and second gear teeth. 3. The power transmission device of claim 2 wherein said first cam plate is fixed for rotation with said first hub segment of said first face gear, wherein said second cam plate is fixed for rotation with said second hub segment of said second face gear, and wherein said rollers are disposed to roll against cam surfaces formed on at least one of said first and second cam plates. 4. The power transmission device of claim 2 wherein said drive gear is fixed to a shaft driven by said electric motor with said drive gear located between said first and second face surfaces of said first and second face gears, respectively. 5. The power transmission device of claim 2 wherein said clutch assembly includes a hub fixed to one of said input and output members, a drum fixed to the other of said input and output members, a clutch pack disposed within said drum and operably connected between said hub and drum, and wherein said first and second cam plates are disposed within said drum. 6. The power transmission device of claim 1 wherein said first face gear is rotatable relative to said second face gear between a first position and a second position in response to activation of said electric motor for causing corresponding axial movement of said first cam plate between a retracted position and an extended position relative to said clutch assembly, said first cam plate exerting a minimum clutch engagement force on said clutch assembly when said cam member is located in its retracted position and exerting a maximum clutch engagement force on said clutch assembly when located in its extended position. 7. The power transmission device of claim 6 wherein said input member provides drive torque to a first driveline of a motor vehicle, wherein said output member is coupled to a second driveline of the motor vehicle, and wherein said torque transfer mechanism is operable to transfer drive torque from said input member to said output member. 8. The power transmission device of claim 7 defining a transfer case wherein said input member is a first shaft driving the first driveline and said output member is a second shaft coupled to the second driveline, wherein location of said first cam plate in its retracted position releases engagement of said clutch assembly so as to define a two-wheel drive mode and location of said first cam plate in its extended position fully engages said clutch assembly so as to define a part-time four-wheel drive mode, and wherein said control system is operable to control activation of said electric motor for varying the position of said first cam plate between its retracted and extended positions to controllably vary the drive torque transferred from said first shaft to said second shaft so as to define an on-demand four-wheel drive mode. 9. The power transmission device of claim 8 wherein said control system includes a controller for receiving input signals from a sensor and generating electric control signals based on said input signals which are supplied to said electric motor for controlling the direction and amount of rotary movement of said drive gear. 10. The power transmission device of claim 7 defining a power take-off unit wherein said input member provides drive torque to a first differential associated with the first driveline, and wherein said output member is coupled to a second differential associated with the second driveline. 11. The power transmission device of claim 1 wherein said input member is a propshaft driven by a drivetrain of a motor vehicle and said output member is a pinion shaft driving a differential associated with an axle assembly of the motor vehicle, and wherein said clutch assembly is disposed between said propshaft and said pinion shaft such that actuation of said clutch actuator assembly is operable to transfer drive torque from said propshaft to said pinion shaft. 12. The power transmission device of claim 1 wherein said input member includes a first differential supplying drive torque to a pair of first wheels in a motor vehicle and a transfer shaft driven by said differential, said output member includes a propshaft coupled to a second differential interconnecting a pair of second wheels in the motor vehicle, and wherein said clutch assembly is disposed between said transfer shaft and said propshaft. 13. The power transmission device of claim 1 wherein said input member includes a first shaft supplying drive torque to a second shaft which is coupled to a first differential for driving a pair of first wheels in a motor vehicle, said output member is a third shaft driving a second differential interconnecting a pair of second wheels of the motor vehicle, and wherein said clutch assembly is operably disposed between said first and third shafts. 14. The power transmission device of claim 1 further including an interaxle differential driven by said input member and having a first output driving a first driveline in a motor vehicle and a second output driving a second driveline in the motor vehicle, and wherein said clutch assembly is operably disposed between said first and second outputs of said interaxle differential. 15. A torque transfer mechanism for transferring drive torque from a rotary input member to a rotary output member, comprising: a friction clutch assembly having a drum fixed for rotation with one of the input member and the output member, a hub fixed for rotation with the other of the input member and the output member, a clutch pack operably disposed between said drum and said hub, and a pressure plate moveable between a first position whereat a minimum clutch engagement force is exerted on said clutch pack and a second position whereat a maximum clutch engagement force is exerted on said clutch pack; a clutch actuator assembly for moving said pressure plate between its first and second positions and including an electric motor driving a geared drive unit for controlling movement of a clutch apply operator, said geared drive unit includes a drive gear driven by said electric motor and first and second face gears with said drive gear in meshed engagement therebetween so as to cause said first and second face gears to rotate in opposite directions in response to driven rotation of said drive gear, said clutch apply operator including a first cam plate fixed for rotation with said first face gear, a second cam plate fixed for rotation with said second face gear and rollers disposed between said first and second cam plates; and a control system for actuating said electric motor so as to control rotary movement of said first face gear relative to said second face gear between a first position and a second position, said first cam plate being located in a first axial position when said first face gear is in its first position so as to cause said pressure plate to be located in its first position, and said first cam plate is located in a second axial position when said first face gear is rotated to its second position so as to cause said pressure plate to move to its second position. 16. The torque transfer mechanism of claim 15 wherein said first face gear includes a first hub segment rotatably supported on the input member and a first ring segment having first gear teeth formed on a first face surface, wherein said second face gear includes a second hub segment rotatably supported on said first hub segment and a second ring segment having second gear teeth formed on a second face surface, and wherein said drive gear is meshed with said first and second gear teeth. 17. The torque transfer mechanism of claim 16 wherein said first cam plate is fixed for rotation with said first hub segment of said first face gear, wherein said second cam plate is fixed for rotation with said second hub segment of said second face gear, and wherein said rollers are disposed to roll against cam surfaces formed on at least one of said first and second cam plates. 18. The torque transfer mechanism of claim 16 wherein said drive gear is fixed to a shaft driven by said electric motor with said drive gear located between said first and second face surfaces of said first and second face gears, respectively. 19. The torque transfer mechanism of claim 15 wherein the input member provides drive torque to a first driveline of a motor vehicle and the output member is coupled to a second driveline of the motor vehicle. 20. The torque transfer mechanism of claim 19 defining a transfer case wherein said input member is a first shaft driving the first driveline and the output member is a second shaft coupled to the second driveline, wherein location of said first cam plate in its first position releases engagement of said clutch assembly so as to define a two-wheel drive mode and location of said first cam plate in its second position fully engages said clutch assembly so as to define a part-time four-wheel drive mode, and wherein said control system is operable to control activation of said electric motor for varying the position of said first cam plate between its first and second positions to controllably vary the drive torque transferred from said first shaft to said second shaft so as to define an on-demand four-wheel drive mode. 21. The torque transfer mechanism of claim 20 wherein said control system includes a controller for receiving input signals from a sensor and generating electric control signals based on said input signals which are supplied to said electric motor for controlling the direction and amount of rotary movement of said drive gear. 22. The torque transfer mechanism of claim 19 defining a power take-off unit wherein the input member provides drive torque to a first differential associated with the first driveline, and wherein the output member is coupled to a second differential associated with the second driveline. 23. The torque transfer mechanism of claim 15 wherein the input member is a propshaft driven by a drivetrain of a motor vehicle and the output member is a pinion shaft driving a differential associated with an axle assembly of the motor vehicle, and wherein said clutch assembly is disposed between said propshaft and said pinion shaft such that actuation of said clutch actuator assembly is operable to transfer drive torque from said propshaft to said pinion shaft. 24. The torque transfer mechanism of claim 15 wherein the input member includes a first differential supplying drive torque to a pair of first wheels in a motor vehicle, and a transfer shaft driven by said first differential, the output member includes a propshaft coupled to a second differential interconnecting a pair of second wheels in the motor vehicle, and wherein said clutch assembly is disposed between said transfer shaft and said propshaft. 25. The power transmission device of claim 15 wherein the input member includes a first shaft supplying drive torque to a second shaft which is coupled to a first differential for driving a pair of first wheels in a motor vehicle and the output member is a third shaft driving a second differential interconnecting a pair of second wheels of the motor vehicle, and wherein said clutch assembly is operably disposed between said first and third shafts.