Rotary actuation mechanism for torque modulated transfer case

In a motor vehicle having an engine and first and second sets of wheels, a transfer mechanism for transmitting drive torque from the engine to the first set of wheels comprising:

• a transfer clutch for selectively transmitting drive torque to the second set of wheels, said transfer clutch being operable for continuously varying the drive torque transmitted therethrough in response to a corresponding variation in a clutch engagement force;
• a drive mechanism for generating said clutch engagement force, said drive mechanism including a lever arm that is supported for pivotal movement between a first position for generation a minimum clutch engagement force and a second position for generating a maximum clutch engagement force, said drive mechanism further including a sector plate coupled to said lever arm and rotatable in a first direction for causing concurrent movement of said lever arm toward said first position and in a second direction for causing concurrent movement of said lever arm toward said second position;
• actuator means for selectively rotating said sector plate so as to cause corresponding pivotal movement of said lever arm between said first position and said second position in response;
• 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 actuator means in accordance with said speed differential signal for continuously varying the torque transmitted through said transfer clutch in response to the position of said lever arm between said first and second positions.

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 continuously varying the torque transmitted therethrough by continuously varying a clutch engagement force;
• a drive mechanism for generating said clutch engagement force, said drive mechanism including a rotatable sector plate and a pivotable lever arm interconnected to said sector plate such that rotation of said sector plate in a first direction causes pivotable movement of said lever arm toward a first position whereat a minimum clutch engagement force is generated, and rotation of said sector plate in a second direction causes pivotable movement of said lever arm toward and a second position whereat a maximum clutch engagement force is generated;
• sensor means for sensing the rotational speed of the first and second sets of wheels and respectively generating first and second speed signals 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 being operable for controlling rotation of said sector plate for continuously varying the torque transmitted through said transfer clutch as a function of said speed differential signal.