Sprial Cam Clutch Actuation System For Two-Speed Transfer Case

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 first 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 second clutch operably disposed between said first and second output shafts;
• an electric motor for rotating a driveshaft;
• and
• a clutch operator having a first member rotatably 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, a cam mechanism for converting rotary movement of said first member into axial movement of said second member, said cam mechanism including a roller mounted to said first member for radial movement and a spiral channel formed in said second member within which said roller is disposed, said channel having a cam surface engaged by said roller and configured to cause movement of said second member between its first and second mode positions in response to rotation of said first member relative to said second member, and a movement coordinating mechanism for controlling relative rotation between said first and second members so as to coordinate movement of said first clutch between its first and second range positions with axial movement of said second member in response to rotation of said driveshaft.

A transfer case comprising:

• an input shaft;
• first and second output shafts;
• a range unit driven by said input shaft and having an output component driven at a reduced speed relative to said input shaft;
• a range clutch operable in a first range position to couple said input shaft to said first output shaft for establishing a high-range drive connection, and in a second range position to couple said output component of said range unit to said first output shaft for establishing a low-range drive connection;
• a mode clutch including a clutch pack operably disposed between said first and second output shafts and a pressure plate moveable between a first mode position whereat a minimum clutch engagement force is exerted on said clutch pack and a second mode position whereat a maximum clutch engagement force is exerted on said clutch pack;
• and
• an actuation mechanism for coordinating movement of said range clutch and said pressure plate, said actuation mechanism including a geartrain having an input gear and an output gear, a motor driving said input gear, a range actuator driven by said output gear for moving said range clutch between its first and second range positions, and a mode actuator driven by said output gear for moving said pressure plate between its first and second mode positions, said mode actuator having a first member driven by said output gear, a second member axially moveable relative to said first member for moving said pressure plate between its first and second mode positions, a cam mechanism for converting rotary movement of said first member into axial movement of said second member, and a movement coordinating mechanism for coordinating movement of said range clutch with that of said pressure plate in response to rotation of said output gear, said cam mechanism including a roller mounted to said first member for radial movement and a spiral channel formed in said second member within which said roller is disposed, said roller engaging a cam surface formed in said channel that is configured to cause axial movement of said second member relative to said first member in response to rotation of said first member relative to said second member.