Linear actuation mechanism for electronically-controlled torque modulated transfer case

A power transfer system for a motor vehicle having an engine and first and second sets of wheels, the power transfer system comprising:

• a transfer mechanism for transmitting drive torque from the engine to the first set of wheels and selectively transmitting drive torque to the second set of wheels through a transfer clutch capable of varying the torque transmitted therethrough by varying a clutch engagement force;
• a drive mechanism for generating said clutch engagement force, said drive mechanism including a lever arm supported for pivotal movement between a first position for generating a minimum clutch engagement force and a second position for generating a maximum clutch engagement force;
• a linear actuator including a linearly extendable member adapted to move said lever arm between said first position and said second position;
• first sensor means for sensing the rotational speed of the first set of wheels and generating a first speed signal indicative thereof;
• second sensor means for sensing the rotational speed of the second set of wheels and generating a second speed signal indicative thereof;
• and
• control means for receiving said first and second speed signals and generating a speed differential signal that is indicative of a speed differential between the first and second sets of wheels, said control means operable for controlling actuation of said linear actuator for varying the torque transmitted through said transfer clutch in response to the position of said lever arm between said first and second positions in accordance with said speed differential signal.

A power transfer system for a motor vehicle having an engine and first and second sets of wheels, the power transfer system comprising:

• a transfer mechanism for transmitting drive torque from the engine to the first set of wheels and selectively transmitting drive torque to the second set of wheels through a transfer clutch capable of varying the torque transmitted therethrough by varying a clutch engagement force;
• a drive mechanism for generating said clutch engagement force, said drive mechanism including a lever arm supported for pivotable movement between a first position for generating a minimum clutch engagement force and a second position for generating a maximum clutch engagement force;
• an electrically-controlled actuator including a linearly extendable output member operably connected to said lever arm such that translational movement of said output member causes corresponding movement of said lever arm between said first position and the second position;
• first sensor means for sensing the rotational speed of the first set of wheels and generating a first speed signal indicative thereof;
• second sensor means for sensing the rotational speed of the second set of wheels and generating a second signal indicative thereof;
• and
• control means for receiving said first and second speed signals and generating a speed differential signal that is indicative of a speed differential between the first and second sets of wheels, said control means operable for controlling actuation of said actuator as a function of said speed differential signal for varying the torque transmitted through said transfer clutch in response to the position of said lever arm.