Mercedes-Benz ML320. Manual

Fig. 56: Planetary Gear Set, Function (1 Of 5)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Operation - The ring gear (1) and sun gear (3) elements of a planetary gear system are alternately driven and
braked by the actuating elements of the multi-plate clutch and multiple-disc brake. See .Fig. 56 The planet gears
(2) can turn on the internal gearing of the ring gear (1) and on the external gearing 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 speed are converted corresponding to the lever ratios or the ratio of the number of teeth on the
driven to the driving gears and is known 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. When two components of the planetary gear set
are locked together, the planetary gear set is locked and turns as a closed unit.

Advantages Of A Planetary 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

The Following Basic Ratio Possibilities Can Be Realized

See Fig. 57.



Sun Gear Locked



Ring Gear Driving



Planet Gears Driven



Relatively Low Step-Down Ratio

2001 Mercedes-Benz ML320

1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662

See Fig. 58.



Hollow Gear Locked



Sun Gear Driving



Planet Gears Driven



Relatively High Step-Down Ratio

2001 Mercedes-Benz ML320

1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662

Mercedes-Benz ML320. Manual - part 160