Patent ID: 6846262
Filing Date: 2005-01-25
Classification: F16D

Abstract:
1. A transfer case comprising: an input shaft; a reduction unit driven by said input shaft and having an output member driven at a reduced speed relative to said input shaft; first and second output shafts; a range actuator moveable between first and second range positions to establish corresponding high-range and low-range drive connections between said first output shaft and said input shaft and said output member; a bi-directional mode clutch having a first ring driven by said first output shaft and a second ring adapted to rotate relative to said first ring for selectively coupling said first ring to said second output shaft, said first ring having a first slot and said second ring having a second slot that is alignable with said first slot to define an actuation chamber having laterally-spaced first and second stop surfaces; a mode actuator moveable between at least three mode positions, said mode actuator is operable in its first mode position to engage said first stop surface in said actuation chamber so as to permit rotation of said second ring relative to said first ring in a first direction and prevent rotation of said second ring relative to said first ring in a second direction to establish an on-demand four-wheel drive mode, said mode actuator is operable in its second mode position to be displaced from engagement with both of said first and second stop surfaces in said actuation chamber so as to permit rotation of said second ring, relative to said first ring in both directions to establish a part-time four-wheel drive mode, and said mode actuator is operable in its third mode position to engage both of said first and second stop surfaces in said actuation chamber so as to prevent rotation of said second ring relative to said first ring in both directions to establish a two-wheel drive mode; a shift mechanism for coordinating movement of said range actuator and said mode actuator, said shift mechanism is operable in a first shift position for locating said range actuator in its first range position and said mode actuator in its first mode position to establish an on-demand four-wheel high-range (AUTO) drive mode, said shift mechanism is operable in a second shift position for locating said range actuator in its first range position and said mode actuator in its second mode position to establish a part-time four-wheel high-range (4WH) drive mode, said shift mechanism is operable in a third shift position for locating said range actuator in its first range position and said mode actuator in its third mode position to establish a two-wheel high-range (2WH) drive mode, and said shift mechanism is operable in a fourth shift position for locating said range actuator in its second range position and said mode actuator in its second mode position to establish a part-time four-wheel low-range (4WL) drive mode; and a control system for controlling movement of said shift mechanism.