The Automotive Gearbox  is a mechanism used to change the speed and torque from the engine, which can change the output shaft and input shaft ratio.

TheAutomotive Gearbox is divided into manual and automatic. The manualAutomotive Gearbox is mainly composed of gears and shafts. The Automotive Gearbox AT is composed of hydraulic torque converter, planetary gear and hydraulic control system. , Through the hydraulic transmission and gear combination to achieve variable speed moment.

ManualAutomotive Gearbox called manual transmission (referred to as MT), also known as mechanical transmission, that is, you must manually dial the shift lever (commonly known as "block") to change the gear within the gear meshing position, change the transmission ratio, so as to achieve the purpose of speed.

Manual transmission working principle

By switching the shift lever, the drive gear on the countershaft is switched by combining the gears of different sizes with the power output shaft to change the torque and speed of the drive wheels.

The engine's power input shaft is indirectly connected to the power output shaft via an intermediate shaft. As shown in the figure above, the two gears (red) of the countershaft and the two gears (blue) on the power output shaft are rotated together with the engine output. However, if there is no synchronizer (purple) of the joint, the two gears (blue) can only idling on the power output shaft (that is, will not drive the output shaft rotation).

When the shift lever is moved to the left, the synchronizer is moved to the right to engage the gear, and the engine is powered by the gear of the countershaft to transmit power to the power output shaft.

Automatic transmission is the use of planetary gear mechanism for speed, it can be based on the accelerator pedal speed and speed changes, automatic speed, and the driver only need to manipulate the accelerator pedal to control the speed.

There are four types of automatic transmission: hydraulic automatic transmission (AT), mechanical stepless automatic transmission (CVT), electronic control mechanical automatic transmission (AMT), dual clutch automatic transmission (Dual Clutch Transmission - DCT) The At present, cars are commonly used AT, AT almost become synonymous with automatic transmission.

AT is composed of hydraulic torque converter, planetary gear and hydraulic control system, through the hydraulic transmission and gear combination to achieve variable speed torque. The hydraulic torque converter is the most important part of the AT, which consists of pump wheel, turbine and guide wheel and other components, both the transmission torque and the role of clutch.

The torque converter is the most characteristic part of the AT, which directly inputs the engine power and transmits the torque, with the clutch action. Pump wheel will be driven by the liquid turbine rotation, and then between the pump wheel and turbine with a guide wheel, through the reaction force between the pump and turbine to achieve speed difference between the variable speed can be achieved. As the torque converter torque range is not large enough, so in the rear of the turbine and then row several rows of planetary gears to improve efficiency, hydraulic control system will work with the engine changes and manipulate the planetary gear, in order to achieve automatic variable torque.