Planetary Gear Drive

Planetary gear box works on planetary motion principle. Each stage of the planetary gear box consists of a central Sun Gear meshing with accurately positioned three Planet Gears around it which in turn mesh with the internal teeth of the outer Ring Gear. Normally, the Ring gear is stationary & forms the part of the housing, input is given to the sun gear & output is derived from the three planet gears through a planet carrier. However, out of these three members any one can be held stationary, second is driven by input and the output can be derived from the third member. Due to this flexibility, planetary gear boxes have a large variety and innumerable applications. As total load is shared by three planets, the torque handling capacity of this type of gear box is very high compared to all other types of gear boxes. Hence, in all high torque applications, planetary gear box is the only economical solution and is most preferred worldwide. It also gives the highest weight volume ratio i.e. in a given space, this type of gear box can handle the highest torque