摘要 |
A shift assembly for a two-speed transfer case utilizes a single actuator to drive both the speed range selection mechanism and a modulating friction clutch pack which selectively transfers drive torque from a primary output to a secondary output. The shift assembly includes an actuator which rotates a shift rail and cam having an intermediate helical track and a dwell region at each end. A lost motion assembly operating in conjunction with the helical cam selectively engages and disengages the clutch when the cam follower is in one of the two dwell regions. Thus, the shift assembly provides sequential operation from full clutch engagement in a first speed range, clutch disengagement in the first speed range, de-selection of the first speed range, selection, and de-selection of neutral, selection of a second speed range and, up to full engagement of the clutch in the second speed range.
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