Planetary Gearboxes

A planetary gearbox consists of a sun gear, the planet gears, the planet gears’ carrier, and the ring gear. Sun gear located at the centre that transmits torque to planet gears orbiting around the sun gear. Planet and the sun gear are located inside the ring gear.

Any planetary gearset has three main components:

• The sun gear
• The planet gears and the planet gears’ carrier
• The ring gear

Each of these three components can be the input, the output or can be held stationary. Choosing which piece plays which role determines the gear ratio for the gearset. Let’s take a look at a single planetary gearset.