What is the basic working principle of a transmission?
2 Answers
Basic working principle of an automotive transmission: A manual transmission primarily consists of gears and shafts, achieving speed and torque variation through different gear combinations. On the other hand, an automatic transmission (AT) is composed of a torque converter, planetary gears, and a hydraulic control system, achieving speed and torque variation through hydraulic power transmission and gear combinations. More details are as follows: 1. Transmissions are divided into manual and automatic types. Manual transmissions mainly consist of gears and shafts, achieving speed and torque variation through different gear combinations. Automatic transmissions (AT) are composed of a torque converter, planetary gears, and a hydraulic control system, achieving speed and torque variation through hydraulic power transmission and gear combinations. 2. Working principle of a manual transmission: By shifting the gear lever, the active gear on the intermediate shaft is switched, combining with the power output shaft through different-sized gear combinations to change the torque and speed of the drive wheels. 3. An automatic transmission uses planetary gear mechanisms for speed variation. It can automatically shift gears based on the degree of throttle pedal input and changes in vehicle speed, while the driver only needs to control the speed via the accelerator pedal. 4. Working principle of an AT automatic transmission: The torque converter is the most distinctive component of an AT. It directly inputs engine power and transmits torque while also functioning as a clutch. The pump wheel drives the turbine to rotate through fluid, and with the addition of a stator between the pump wheel and turbine, a speed difference between the pump wheel and turbine can be achieved through reaction force, enabling speed and torque variation. Since the automatic speed and torque variation range of the torque converter is not sufficiently large, several rows of planetary gears are connected in series behind the turbine to improve efficiency. The hydraulic control system automatically operates the planetary gears in response to changes in engine operation, thereby achieving automatic speed and torque variation.
I've previously studied automotive transmissions, and simply put, they're like the gear sets on a bicycle. The power generated by the engine is input into the transmission via the driveshaft, where a combination of gears of various sizes are housed. When you press the accelerator while driving, these gears mesh with each other to alter the output speed and torque. For instance, when climbing a hill that requires more power, you shift to a lower gear where the gear ratio increases, resulting in stronger torque. Conversely, during high-speed cruising, higher gears are used to reduce engine speed, which in turn saves fuel. Manual transmission vehicles rely on the driver to control the gear shift lever, whereas automatic transmissions use computers and hydraulic systems to assess vehicle speed and throttle depth, automatically shifting gears accordingly. Key components also include synchronizers, which allow for smooth gear engagement and prevent gear grinding. The overarching design goal is to keep the engine operating within its most efficient range, ensuring optimal performance whether starting, accelerating, or cruising at high speeds.
