Planeettapyörö

Planeettapyörö is a Finnish term that translates to "planetary gearset" in English. It refers to a type of mechanical gear system that consists of one or more external gears (planet gears) rotating around a central sun gear. The planet gears are mounted on a carrier, which can also rotate. This entire assembly is typically enclosed within an outer ring gear, also known as an annulus.

The fundamental principle of a planetary gearset is its ability to transmit torque and modify speed and direction of rotation. By holding one of the three main components (sun gear, planet carrier, or ring gear) stationary while driving another, different gear ratios can be achieved. For instance, if the ring gear is held stationary, the output speed from the planet carrier will be higher than the input speed of the sun gear, and the direction of rotation will be the same. If the sun gear is held stationary, the output from the planet carrier will be slower, and the direction will be reversed.

Planetary gearsets are renowned for their compact size, high torque capacity, and ability to provide multiple gear ratios within a single unit. Their efficiency is also a significant advantage. These characteristics make them ideal for a wide range of applications, most notably in automatic transmissions for vehicles. They are also found in other machinery such as wind turbines, industrial gearboxes, and even some types of bicycle hubs. The versatility and efficiency of the planeettapyörö system have made it a cornerstone of modern mechanical engineering.