GF27.50-P-5100-01N Planetary gear set, function Transmission 722.9 in model 171.4, 203, 209, 211, 215, 219, 220, 230
Ravigneaux gear set

Ravigneaux gear set

1 Short planet gear
2 Long planet gear
3 Sun gear
4 Planet carrier
 
    P27.50-2097-76

The elements hollow gears, sun gear (3) and planet carrier (4) of the Ravigneaux gear set used are driven or stalled alternately via the shift elements of multi-disk clutch and multi-disk brake. In this process, the planetary gears can roll on the internal toothing of the ring gears and on the external toothing of the sun gear (3). This allows for a variety of gear ratios and the reversal of the rotation direction without the need for moving gear wheels or shift collars.
The torque and engine speed are converted according to the lever ratios or the ratio of the number of teeth on the driven gears to that on the drive gears, and is referred to as the gear ratio i. The overall ratio of a number of planetary gear sets connected in series is obtained by multiplying the partial ratios.
  If 2 components of the Ravigneaux gear set are rigidly connected to each other, the planetary set is blocked and rotates as a closed unit.

Advantages of a Ravigneaux gear set
Shifting ability under load
Several ratios can be produced
Constant meshing of the gears
Simple direction reversal
High efficiency
Coaxial location of input and output
Compact design
Combined 2 single planetary gear systems in one unit