Automotive transmissions can be divided into manual transmissions and automatic transmissions based on their control methods. Common automatic transmissions mainly include four types: Automated Manual Transmission (AMT), Hydraulic Automatic Transmission (AT), Continuously Variable Transmission (CVT), and Dual-Clutch Transmission (DSG). Below are their structures and working principles: 1. Structure and Working Principle of Manual Transmission: A manual transmission mainly consists of a housing, transmission components (input/output shafts, gear synchronizers, etc.), and control components (shift levers, shift forks, etc.). By moving the gear lever, the driving gears on the intermediate shaft are switched, and different gear combinations engage with the power output shaft to change the torque and speed of the driving wheels. 2. Structure and Working Principle of Hydraulic Automatic Transmission: A torque converter generally consists of a pump impeller, stator, turbine, and lock-up clutch. The transmission is filled with transmission fluid. When the pump impeller, connected to the power input shaft, rotates, it drives the turbine, connected to the output shaft, to rotate together through the transmission fluid, thereby transmitting the engine power. 3. Structure and Working Principle of Continuously Variable Transmission: The main components of a CVT are two pulleys and a metal belt. The metal belt is looped around the two pulleys. Each pulley consists of two discs, with a V-shaped groove formed between them. One of the discs is controlled by a hydraulic mechanism, allowing it to move apart or closer depending on the engine speed. The V-shaped groove thus widens or narrows, raising or lowering the metal belt, which changes the contact diameter of the belt with the pulley, effectively simulating gear shifts by switching gears of different diameters. 4. Structure and Working Principle of Dual-Clutch Transmission: Two clutches are assembled within the same mechanism as the transmission. One clutch is responsible for gears 1, 3, 5, and reverse, while the other handles gears 2, 4, and 6. When the driver engages 1st gear to start, the shift fork simultaneously engages 1st and 2nd gears, but clutch 1 is engaged while clutch 2 is disengaged, so power is transmitted through the 1st gear, and the 2nd gear idles. When shifting to 2nd gear, the shift fork simultaneously engages 2nd and 3rd gears, clutch 1 disengages while clutch 2 engages, transmitting power through the 2nd gear, and the 3rd gear idles.
