WHAT IS A PLANETARY GEARBOX?

A planetary gearbox is a gearbox with the input shaft and the output shaft aligned. A planetary gearbox is utilized to transfer the largest torque in the the majority of compact form (known as torque density).

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

In mathematical terms, the tiniest reduction ratio is 3: 1, the largest is 10: 1. At a ratio of significantly less than 3, the sun gear becomes too large against the planet gears. At a ratio greater than 10 the sun wheel becomes too little and the torque will drop. The ratios are usually absolute i.e. an integer number.

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