A planetary gearbox is a gearbox with the insight shaft and the result shaft aligned. A planetary gearbox can be used to transfer the largest torque in the the majority of compact form (referred to as torque density).

The bicycle’s acceleration hub is a good exemplory case of a planet-wheel mechanism: Have you ever wondered how you can get so much power and features in such a small hub? For a three-velocity hub, a one-stage planetary equipment system can be used, for a five-quickness hub a 2-stage. Each planet gear program has a reduction state, a primary coupling and an acceleration setting.

In mathematical terms, the tiniest reduction ratio is 3: 1, the biggest is 10: 1. At a ratio of less than 3, the sun gear becomes too big against the earth gears. At a ratio greater than 10 the sun wheel becomes too small and the torque will drop. The ratios are often absolute i.electronic. an integer number.

Whoever invented the planetary gearbox is not known, but was functionally described simply by Leonardo da Vinci in 1490 and has been used for centuries.