The basic structure of the planetary gearbox

Structure composition 
1.Simple (single row) planetary gearbox mechanism is the basis of transmission mechanism. Generally, the transmission mechanism of automatic transmission is composed of two or more rows of planetary gear mechanisms. The simple planetary gear mechanism comprises a sun gear, several planetary gears and a gear ring, wherein the planetary gear is supported by the fixed shaft of the planet carrier, allowing the planetary gear to rotate on the supporting shaft. Planetary gears are always in constant meshing with adjacent sun gears and ring gears. Helical gears are usually used to improve the stability of work.

2.In a simple planetary gear mechanism, the sun gear is located in the center of the planetary gear mechanism. The sun gear and the planetary gear are often meshed, and the two external gears mesh and rotate in the opposite direction. Just as the sun is at the center of the solar system, the solar wheel is named for its position. In addition to rotating around the support shaft of the planet carrier, under some working conditions, the planet gear will also rotate around the central axis of the sun gear driven by the planet carrier, just like the rotation of the earth and the revolution around the sun. When this happens, it is called the transmission mode of the planetary gear mechanism. In the whole planetary gear mechanism, if the rotation of the star wheel exists, and the star carrier is fixed, this way is similar to the parallel shaft transmission, which is called fixed shaft transmission. The ring gear is an internal gear, which is often meshed with the planetary gear. It is meshed with the internal gear and the external gear, and the rotation direction between them is the same. The number of planetary gears depends on the design load of the transmission, usually three or four. The more the number, the greater the load.

 

3.Planetary gear mechanism is usually called three component mechanism. The three components refer to sun gear, planet carrier and ring gear respectively. If the three components want to determine the motion relationship between each other, generally, one of them needs to be fixed first, then determine who is the active part, and determine the speed and rotation direction of the active part. As a result, the speed and rotation direction of the passive part are determined.