Figure 6-9. - Planetary gear arrangements that will provide an increase or decrease in speed.

In figure 6-9 notice the direction of rotation as power is applied to the various members and others are stationary. In actual application, planetary gearsets are used as single or multiple units, depending on the number of speed (gear) ranges desired.

On tracked equipment, power for turning the drive sprockets may flow through a planetary gear arrangement that provides maximum reduction (fig. 6-9). The sun gear forces the planetary gears to revolve in the stationary ring gear and move the carrier in the same direction of rotation as the sun gear. The carrier is connected to the hub on which the sprocket is mounted, causing it to rotate with the carrier. This arrangement produces the maximum torque and speed reduction obtainable from a planetary gearset.

Planetary Steering

Some tracked equipment may be steered by a system that combines planetary steering and pivot