Adaptation of shift mechanism of mechanical gear-boxes for automation

摘要

The automated gear boxes are more and more often used in passenger cars thanks to their combination of advantages of two mainly used gearbox types - mechanical gearboxes (high efficiency, low manufacturing costs) and Automatic Gearboxes (high driving comfort). Nevertheless the automated gear boxes have a big handicap concerning the shifting with break of torque flow. The smooth shifting of the gears requires very short shift time, which in gearboxes with internal synchronization can't be shorter than allowed by the capacity limit of the synchronizers. One way how to approach the smooth shifting of automatic gear boxes while keeping the high efficiency of the powertrain, is to adapt the mechanical gearbox shift mechanism for automation. The article will be focused on the design of - in serial produced cars - non-conventional shift mechanisms intended for automation. The paper will present a comparison of gearboxes with internal synchromesh mechanisms and gearboxes with pure shift mechanisms with external synchronization. Also several concepts of external synchronization will be shown. The article will outline on this basis future promising developments of automated gearboxes using non-conventional shift-mechanisms.