Planetary gearbox automatic transmission
The planetary gearbox in an automatic transmission (AT) is a power transmission mechanism that converts engine speed and torque for optimal vehicle performance.
Design and principle of operation:
The planetary gearbox consists of the following elements:
*Sun Gear: The center gear to which the motor axle is connected.
* Planetary Gears: Smaller gears that rotate around the sun gear using a planetary holder.
* Inner Gear (Ring): An outer gear with internal teeth that interact with the planetary gears.
The input shaft axis is connected to the sun gear, which drives the planetary gears. The planetary gears, in turn, rotate around an internal gear, which is connected to the output shaft.
Depending on which element is fixed and which rotates, different gear ratios can be obtained:
*Ramp Gear: If the sun gear is fixed and the inner gear rotates, the planetary gears rotate around it, increasing the rotation speed of the output shaft.
* Reduction gear: If the inner gear is fixed and the sun gear rotates, the planetary gears rotate around it, reducing the rotation speed of the output shaft.
* Torque Variable Transmission: When the planetary carrier is fixed and the sun gear and inner gear rotate together, torque is transferred from the sun gear to the inner gear, increasing the torque on the output shaft.
Advantages:
* Compact design and low weight.
* Wide range of gear ratios in one device.
*High power transmission efficiency.
* Smoothly variable gear ratio.
Planetary gearboxes are widely used in automatic transmissions for automatic gear shifting, ensuring the optimal combination of speed and torque under various operating conditions.