Planetary gear in an automatic transmission
Planetary gearing is one of the key components of automatic transmissions (automatic transmissions). It is used to transmit torque and change the gear ratio between the engine and the wheels.
Planetary gear design
The planetary gear consists of the following components:
* Sun Gear: It is located in the center of the transmission and is rigidly connected to the input shaft.
* Planetary Gears: These are located on a rotating carrier called an epicyclic gear.
* Carrier: This is a ring with internal teeth that surrounds the planetary gears and is connected to the output shaft.
* Ring Gear: It is located on the outer side of the gear and is rigidly connected to the gearbox housing.
Operating principle
The operation of a planetary gear is based on the interaction of gears with different numbers of teeth. As the input shaft rotates, the sun gear meshes with the planetary gears. The planetary gears, in turn, mesh with the carrier. If the carrier is locked, the planetary gears will rotate around the sun gear. However, if the carrier is rotating, the planetary gears will rotate around both the sun gear and the carrier.
The relative rotation of the planetary gears and carrier determines the transmission ratio. There are three main modes of operation of the planetary gear:
* Summation: When the carrier is locked, the gear ratio is 1:1.
*Reduction: When the carrier rotates in the same direction as the input shaft, the gear ratio becomes less than 1.
*Increase: When the carrier rotates in the opposite direction compared to the input shaft, the gear ratio becomes greater than 1.
Application in automatic transmission
An automatic transmission uses a planetary gear to create many different gear ratios. This is achieved by combining multiple planetary gears with various control components such as friction clutches and brake bands. The combination of these elements allows the transmission to automatically shift gears, optimizing performance and fuel economy.
Planetary gearing is a reliable and efficient way to transmit torque and change gear ratios. It has been used in automatic transmissions for many decades and continues to be an important component of modern automatic transmissions.