How a Planetary Gear Set Changes Torque Through One Housing

Three small gears orbit one big gear — and that's how your automatic transmission multiplies torque. This 3D animated cutaway follows the force path: the input shaft spins the sun gear, the planet gears roll between the sun and locked ring gear, and the carrier turns the output shaft slower — but stronger. Slow in, strong out. That's the magic. Where else have you seen planet gears at work?