Design and principle of operation of an automatic transmission for gear shift drive
An automatic transmission (automatic transmission) is a mechanical drive that automatically changes gears depending on the speed of the vehicle and the load on the engine. Its main components:
* Torque Converter: Converts torque from the engine into hydraulic pressure.
* Planetary gear: a mechanism that transmits torque to the wheels.
*Clutch Discs and Brake Bands: Used to engage and disengage gears.
* Hydraulic control unit (hydraulic unit): hydraulic fluid distributor that controls the operation of the automatic transmission.
* Electronic control unit (ECU): controls the valve body based on signals from vehicle sensors.
Working principle:
1. When the ignition is turned on, the ECU receives signals from the sensors and calculates the optimal gear for the current driving conditions.
2. The valve body directs hydraulic fluid to the corresponding clutch discs or brake bands.
3. The clutch discs close, transmitting torque to the planetary gear.
4. Brake bands stop certain elements of the planetary gear, ensuring the desired gear.
5. The hydraulic control unit continuously monitors engine and vehicle parameters, adjusting transmission as conditions change.
Automatic transmission types:
*Hydraulic automatic transmission: shifts gears exclusively using hydraulic fluid.
* Electronic-hydraulic automatic transmission: uses electronics to regulate hydraulic pressure, providing smoother shifts.
*Dual Clutch (DSG) and Variable Transmission (CVT): More modern automatic transmission types that offer increased efficiency and performance.
Advantages of automatic transmission:
*Easy to use: No need to use a clutch or operate gear changes manually.
* Smooth shifts: The automatic transmission provides smooth transitions between gears, increasing driving comfort.
* Optimum fuel efficiency: Automatic gear selection ensures the engine operates in the most efficient rpm range.
* Engine and transmission protection: Automatic transmission prevents engine and transmission overloads by limiting speed and torque.