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Planetary Gear Set Component Description - GF27.50-D-2100HAG

TRANSMISSION 722.9 in MODEL 906 

Sectional view of automatic transmission 

G10885831Courtesy of MERCEDES-BENZ USA

Location 

The front and rear single planetary gear set (12a, 12b) are located in the mechanical part of the transmission.

Task 

The task of the front and rear single planetary gear set (12a, 12b) is that of power transmission and generating different gear ratios.

Design 

Illustration shows single planetary gear set 

G10885832Courtesy of MERCEDES-BENZ USA

A single planetary gear set consists of a ring gear (3), the planet gears (1) supported on bearings in the planet carrier (2) and a sun gear.

Function 

The ring gear (3), sun gear and planet carrier (2) elements of a single planetary gear set are driven or stalled alternately via the shift elements of the multidisk clutch and multidisk brake. In the process, the planetary gears (1) can roll on the internal toothing of the ring gear (3) and on the external toothing of the sun gear. 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 conversion and RPM conversion takes place corresponding to the lever ratios or the ratio of the number of teeth of the driven to the driving gear wheels and is designated as the gear ratio i. With several planetary gear sets connected behind each other the overall ratio is given by the multiplication of part ratios.

If 2 components of a single planetary gear system are rigidly connected to each other, then this is locked and rotates as a closed unit.

Advantages of a single planetary gear system: