gf2750s5100b

Planetary gear set, location/purpose/design/function

Type gf · topic 27.50 · version 0102 · 1999-08-16

Applies to: MODEL 638.244 MODEL 638.294 with CODE (MR9) engine M104 V6 (128kW) Euro III

Where it sits

Function group 2 Chassis › 27 Automatic transmission › 27.50 Gear assembly — Series 638 (models 244, 294)

GF27.50-S-5100B

Planetary gear set, location/purpose/design/function

9.4.97

MODEL 638.244

MODEL 638.294 with CODE (MR9) engine M104 V6 (128kW) Euro III

Planetary gear set, location/purpose/design/function

S27.50-2500-11

1 Large sun gear
2 Small sun gear
3 Long planetary gears
4 Short planetary gears
5 Planetary gear carrier
6 Input gear
7 Input, planetary gear carrier
8 Input, large sun gear
9 Input, small sun gear

Planetary gear set, location

GF27.50-S-5100-04B

Planetary gear set, task

In a fully automatic transmission the ratios are produced using a planetary gear set.

Advantages:

- Uninterrupted power flow possible

- Compact construction

- Distribution of power to several gear wheels

- Several ratios possible

Planetary gear set, design

This is a Ravigneaux transmission. The special feature of this is the common planetary gear carrier (5) for all planetary gears (3, 4). In the Ravigneaux transmission the long planetary gears (3) are engaged with the large sun gear (1) and the planetary gears (4) of the small sun gear (2) at the same time. The power is transferred via the drive pinion (6).

Planetary gear set, function

The ratios and different direction of rotation of the planetary gear set result from holding the small or large sun gear (1, 2) and/or the planetary gear carrier (5) securely. They are either connected to each other by the multiple-disc clutches or multiple-disc brakes by means of friction. If two elements are connected by friction at the same time, the planetary gear set is locked and therefore the direct gear 1:1 is engaged (shift stage 3).

Referenced documents