planetary gearsets Archives - Transmission Digest
The evolution of transmissions

The easiest thing to say would be: The manual transmission was first and the automatic came second. End of article. Well, that’s true… sort of.

Gear Head

Our instructor began by teaching us that a simple planetary gear set consists of 1) a center sun gear, 2) a carrier with three or more pinion gears that are free to rotate on their pins around the sun gear and 3) the internal ring gear, which meshes with the pinion gears. Then he started to say, “If you hold the internal gear stationary and drive the sun gear, you will see the pinions drive the carrier in the same direction as the sun gear but at a reduced speed with increased power.” This is where some of my fellow classmates started to get bored.