Power Flow In 2ND Gear Function

Fig 1: Power Flow In 2nd Gear Function

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Principals of power transmission in 2nd gear

Torque from the torque converter is increased via the propeller shaft (1) and the center and rear planetary gearsets and transferred to the output shaft (5).

The following are not engaged:

• Front multi-disc brake (B1).
• Center multi-disc brake (B3).
• Freewheel (F1).
• Center multi-disc clutch (K2).

Front Planetary Gear Set 

The planet carrier (V3) and sun gear (V1) are rigidly connected to each other via the engaged front multi-disc clutch (K1). The planetary gearset is therefore blocked and turns as a closed unit at the input speed due to the mechanical connection of the ring gear (V4) and propeller shaft.

Rear Planetary Gear Set 

The internal gear (H4) turns at the input speed because of its mechanical connection to the front planet carrier (V3). The sun gear (H1) is supported via the engaged rear multi-disc brake (B2) and in drive mode via the locked freewheel (F2), in overrun mode via the engaged rear multi-disc clutch (K3) in the housing. The planet gears (H2) roll over the fixed sun gear (H1) and provide an increase in torque between the internal gear (H4) and the planet carrier (H3). The planet carrier (H3) moves at a reduced speed in the direction of engine rotation.

Center Planetary Gear Set 

The ring gear (M4) is driven at the same speed as the rear planet carrier (H3) as a result of a mechanical connection. The sun gear (M1) is supported in the housing via the rear multi-disc brake (B2). The planet gears (M2) roll over the fixed sun gear (M1) and provide an increase in torque between the internal gear (M4) and the planet carrier (M3). The output shaft (5) connected to the planet carrier (M3) turns at a reduced speed in the running direction of the engine.

1. Torque Converter, Location/Task/Design/Function
   
   See TORQUE CONVERTER, LOCATION/TASK/DESIGN/FUNCTION  .
2. Planetary Gear Set, Location/Task/Design/Function
   
   See PLANETARY GEAR SET, LOCATION/TASK/DESIGN/FUNCTION  .
3. Multiple-Disc Brake, Location/Task/Design/Function
   
   See MULTIPLE-DISC BRAKE, LOCATION/TASK/DESIGN/FUNCTION  .
4. Multi-Plate Clutch, Location/Task/Design/Function
   
   See MULTI-PLATE CLUTCH, LOCATION/TASK/DESIGN/FUNCTION  .
5. Location/Task/Design/Function Of Freewheel
   
   See LOCATION/TASK/DESIGN/FUNCTION OF FREEWHEEL  .