Dual transmission system and its power shift mechanism

摘要

A transmission system including a main transmission and an auxiliary transmission. The main transmission includes at least two transmission trains of multiple gears mounted on respective parallel shafts so that the gears of different trains are selectively engageable. The auxiliary transmission includes a planetary system having an offset pinion gear, mounted on a carrier, engaged between an inner gear and an internally toothed outer gear. The carrier, inner gear and outer gear are coaxial with one of the shafts of the main transmission. The planetary gear system can be controlled so as to fix the rotation of the inner gear or to rotationally link the inner gear to the carrier, thereby providing two speed steps. All the shifting is controlled by one shifting drum.