planetary reducer

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

The bicycle’s acceleration hub is a great example of a planet-wheel mechanism: Have you ever wondered how you can get so much power and capabilities in such a little hub? For a three-speed hub, a one-stage planetary gear system is used, for a five-speed hub a 2-stage. Each planet gear system has a reduction state, a direct coupling and an acceleration mode.

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

What are the purchase criteria for a planetary gearbox? That is a difficult to answer question, because it is highly dependent on where the gearbox is used precisely. First of all, the primary specifications (eg.: torque, backlash, ratio) must be correct, but then the secondary (eg.: corrosion resistance, noise level, construction) and the tertiary (eg.: delivery time, price, global availability, service) are important.

Because FHT runs faster, you can contact us for all your questions. We will reply fast, often the same day, with a customised response and/or customised offer. This way, you never have to worry about a delay, we deliver every gearbox out of stock and faster than anyone else.