Fig. 6.11. Planetary mechanism of automatic transmission: 1 – reduced element; 2 – blocking element
The basis of the automatic transmission is the so-called planetary mechanism. It consists of a toothed wheel (sun gear), around which three other gears (satellites) rotate. The design is closed by an external gear wheel with an internal arrangement of teeth (ring gear). The method of connecting gears is unique. In a planetary mechanism, all gears are in constant engagement. Step transmission occurs without interruption of the torque flow due to the blocking and inclusion of free running of the satellites, sun and crown gears (Fig. 6.11).
Gear shifting thus occurs without interrupting the power flow. Locking and starting are performed by multi-disc brakes and hydraulically driven clutches. Three planetary mechanisms are installed in a row on the multi-stage automatic transmission. This is how the automatic transmission is arranged with three forward and one reverse gear.