A planetary gearbox is a gearbox with the input shaft and the output shaft aligned. A planetary gearbox is utilized to transfer the biggest torque in the most compact form (referred to as torque density).

The bicycle’s acceleration hub is a good example of a planet-wheel mechanism: Perhaps you have ever wondered ways to get so much power and capabilities in such a small hub? For a three-velocity hub, a one-stage planetary equipment system can be used, for a five-rate hub a 2-stage. Each planet gear program has a reduction state, a direct coupling and an acceleration mode.

In mathematical terms, the smallest reduction ratio is 3: 1, the biggest is 10: 1. At a ratio of less than 3, sunlight gear becomes too large against the planet gears. At a ratio higher 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 isn’t known, but was functionally described by Leonardo da Vinci in 1490 and has been used for centuries.