What does an automatic transmission usually consist of?
2 Answers
Automatic transmissions are composed of two types: stepped transmissions and continuously variable transmissions. Below is an introduction to each: 1. A stepped transmission has a limited number of fixed gear ratios (typically 3 to 5 forward gears and 1 reverse gear). 2. A continuously variable transmission allows the gear ratio to change continuously within a certain range, and its application in automobiles has been gradually increasing. Here is a brief introduction to transmissions: As the name suggests, the function of a transmission is to change speed. Through the gear set mechanism, controlled by a control mechanism and coupled with a clutch, it achieves the function of changing speed. Automatic transmissions are generally hydraulic torque converter-type automatic transmissions, which mainly consist of two parts.
As a veteran driver with decades of experience, I find automatic transmissions quite complex. They primarily use a torque converter for starting, which replaces the manual transmission's clutch, making power delivery smoother. The planetary gear set is key—it's like a miniature solar system, achieving different gears through gear combinations. There are also clutch packs and brake bands that lock or release gears under hydraulic pressure. The valve body controls oil pressure, while the oil pump and dedicated transmission fluid ensure lubrication and cooling. Modern vehicles add electronic control units that automatically shift gears based on speed sensors. Early automatic transmissions were bulky, slow to shift, and fuel-inefficient, but they've become smarter with electronic advancements. Remember, dirty transmission fluid can cause overheating and wear, leading to jerky driving if not changed regularly. Overall, automatic transmission cars are much more comfortable to drive, but with more components, don't skimp on maintenance.
