Introduction Of Planetary Gears

Planetary gears mean that the axis of rotation is not fixed and is mounted on a rotatable bracket. In addition to planetary gears that can rotate around their own rotating shafts like fixed-axis gears, their rotating shafts also rotate with the planet carrier around the axis of other gears. The rotation around its own axis is called “rotation”, and the rotation around the axis of other gears is called “revolution”, just like the planets in the solar system, hence the name.The planetary gear mechanism is divided into single planetary row and double planetary row according to the number of planetary gears installed on the planet carrier.

Compared with ordinary gear transmission, planetary gear transmission has many unique advantages. The most notable feature is that power can be split when transmitting power, and the input shaft and output shaft are on the same horizontal line. Therefore, planetary gear transmission has been widely used in reducers, speed increasers and transmission devices in various mechanical transmission systems. In particular, it has been widely used in aircraft and vehicles (especially heavy vehicles) because of its “high load and large transmission ratio” characteristics. [1] Planetary gears also play a big role in the torque transmission of the engine. Since the characteristics of the engine’s speed and torque are very different from the demands of road driving, the power of the engine should be appropriately distributed to the driving wheels, and the above-mentioned characteristics of the planetary gear can be used for conversion. Automatic transmissions in automobiles also use these characteristics of planetary gears to obtain different transmission ratios by changing the relative motion relationship of various components through clutches and brakes.
However, due to the complex structure and working conditions of planetary gears, its vibration and noise problems are also prominent. It is extremely prone to failure phenomena such as gear tooth fatigue pitting, tooth root cracks and even gear teeth or shaft fracture, which affects the operation accuracy of the equipment Transmission efficiency and service life.