Working Principle of Planetary Gears

The principle of fixed gear transmission is very simple.

In a pair of intermeshing gears, there is a gear as the driving wheel, and the power is input from it.

Another gear acts as a driven wheel and power is output from it.

There are also gears only as a transfer station.

One side engages with the drive wheel and the other side engages with the driven wheel, and power passes through it.

This type of gear is called an idler.

In a gear system that includes planetary gears, the situation is different.

Since there are planet carriers, that is, there are three rotating shafts that allow power input/output, and a clutch or brake can be used.

Limit the rotation of one of the shafts when needed, leaving the two shafts for transmission.

In this way, the relationship between the intermeshing gears can be combined in many ways:

The power is input from the sun gear, output from the outer ring gear, and the planet carrier is locked by the mechanism;

The power is input from the sun gear, output from the planet carrier, and the outer ring gear is locked;

Power is input from the planet carrier, output from the sun gear, and the outer ring gear is locked;

Power is input from the planet carrier, output from the outer ring gear, and the sun gear is locked;

Power is input from the outer ring gear, output from the planet carrier, and the sun gear is locked;

Power is input from the outer ring gear, output from the sun gear, and the planet carrier is locked;

The two powers are input from the sun gear and the outer ring gear respectively, and are synthesized and output from the planet carrier;

The two powers are input from the planet carrier and the sun gear respectively, and are combined and output from the outer ring gear;

The two powers are input from the planet carrier and the outer ring gear respectively, and are combined and output from the sun gear;

The power is input from the sun gear and is output in two ways from the outer ring gear and the planet carrier;

Power is input from the planet carrier and is output in two ways from the sun gear and the outer ring gear;

The power outer ring gear is input in two ways from the sun gear and the planet carrier.

We know that there is only one car engine and four wheels.

The characteristics of the engine’s speed and torque are quite different from driving requirements on the road.

To properly distribute the power of the engine to the drive wheels, the above characteristics of the planetary gears can be utilized.

Such as automatic transmissions, but also the use of these characteristics of planetary gears.

Different gear ratios are obtained by varying the relative motion relationship of the various components by the clutch and brake.