Power transmission device with electrohydraulic clutch actuator

A power transfer device for use in a motor vehicle having a powertrain and first and second drivelines, comprising:

• a first shaft driven by the powertrain and adapted for connection to the first driveline;
• a second shaft adapted for connection to the second driveline;
• a torque transmission mechanism for transferring drive torque from said first shaft to said second shaft, said torque transmission mechanism including a transfer clutch operably disposed between said first shaft and said second shaft and a clutch actuator for engaging said transfer clutch, said transfer clutch including a first clutch member driven by said first shaft, a second clutch member driven by said second shaft and a clutch pack operably disposed between said first and second clutch members, said clutch actuator includes a rotary operator and a thrust mechanism, said rotary operator having first and second components which define an actuation chamber that is adapted to receive pressurized fluid, said first component is fixed for rotation with one of said first and second clutch members and said second component is adapted to rotate relative to said first component in response to the pressurized fluid in said actuation chamber, said thrust mechanism is operable for applying a clutch actuation force to said clutch pack in response to rotation of said second component relative to said first component;
• and
• a control system for regulating the pressurized fluid supplied to said actuation chamber.

A power transfer device for use in a motor vehicle having a powertrain and first and second drivelines, comprising:

• an input member adapted to receive drive torque from said powertrain;
• a first output member adapted to provide drive torque to the first driveline;
• a second output member adapted to provide drive torque to the second driveline;
• a gearset operably interconnecting said input member to said first and second output members;
• a torque transmission mechanism for limiting speed differentiation between said first and second output members, said torque transmission mechanism including a transfer clutch operably disposed between any two of said input member and said first and second output members and a rotary operator for controlling engagement of said transfer clutch, said rotary operator having first and second components defining an actuation chamber therebetween that is adapted to receive pressurized fluid, said first component is fixed for rotation with one of said input and output members and said second component is adapted to rotate relative to said first component in response to the pressurized fluid in said actuation chamber for causing a clutch actuation force to be applied to said transfer clutch, and
• a hydraulic control system for regulating the pressurized fluid supplied to said actuation chamber.

A torque transfer mechanism for controlling transfer of drive torque between first and second rotary members comprising:

• a transfer clutch operably disposed between the first and second rotary members;
• a rotary clutch operator having first and second components defining an actuation chamber therebetween;
• a ball ramp unit operably disposed between said second component of said rotary clutch operator and said transfer clutch;
• and
• a hydraulic control system operable for controlling fluid pressure delivered to said actuation chamber so as to control angular movement of said second component relative to said first component for controlling the magnitude of a clutch engagement force applied by said ball ramp unit to said transfer clutch.