Performance of multicone synchronizers for manual transmissions

Theoretical performance equations are derived for multicone synchronizers w hich have replaced the traditional single-cone device in certain upmarket p assenger vehicles. The equations are used to demonstrate the potential impr ovements in shift quality for a typical vehicle. Experimental studies of eq uivalent single- and triple-cone synchronizers within the same gearbox test rig are also reported for transmission oil temperatures ranging from cold start (0 degrees C) to maximum operating conditions (75 degrees C). The res ults confirm the overall much improved performance of the multicone synchro nizer compared with the single-cone equivalent, except at low oil temperatu res, where some difficulty in dissipating the oil from the multiple frictio n surfaces was apparent.