The gearbox mainly refers to the car’s gearbox. It is divided into two types: manual and automatic. The manual gearbox is mainly composed of gears and shafts. The variable speed and torque are generated by different gear combinations. Torque, planetary gear, hydraulic variable pitch system and hydraulic control system. Variable speed and torque are achieved through the combination of hydraulic transmission and gears.
The gearbox is a very important part of the vehicle. It can change the transmission ratio and expand the role of driving wheel torque and speed.
The gearboxes are roughly classified into manual gearboxes, ordinary automatic gearboxes / common automatic gearboxes with automatic transmission, CVT continuously variable gearboxes / CVT gearboxes with gears, dual-clutch gearboxes, and serial gearboxes.
Divided by transmission ratio change (1) Stepped transmission: Stepped transmission is the most widely used one. It adopts gear transmission and has several fixed value transmission ratios. Depending on the type of gear train used, there are two types: an axis-fixed transmission (common transmission) and an axis-rotation transmission (planetary gear transmission). Transmission ratios for cars and light and medium-duty truck transmissions usually have 3-5 forward gears and one reverse gear. In combination transmissions for heavy-duty trucks, there are more gears. The so-called number of transmission gears refers to the number of forward gears. (2) Continuously variable transmission: The transmission ratio of the continuously variable transmission can be infinitely variable in a certain value range. There are two types: electric and hydraulic (hydraulic). The variable speed transmission component of the electric continuously variable transmission is a DC series motor. In addition to its application in trolleybuses, it is also widely used in the super heavy dump truck drive train. The transmission component of the hydrostatic continuously variable transmission is a torque converter. (3) Comprehensive transmission: A comprehensive transmission is a hydromechanical transmission composed of a torque converter and a geared stepped transmission. Its transmission ratio can be in a few discontinuous ranges between the maximum and minimum values. Internally made stepless changes, more applications.
Divided by manual and automatic (1) Manual transmission Manual transmission, also known as manual gear, means that the gear meshing position in the transmission can be changed by manually shifting the gear lever to change the gear ratio, thereby achieving the purpose of speed change. When the clutch is depressed, the shift lever can be moved. If the driver is skilled, a car with a manual transmission will be faster than an automatic transmission when accelerating or overtaking, and it will also save fuel. AMT gearbox is a type of manual gearbox. Its advantages are fuel saving and low price. The disadvantage is that there are few application models and the technology is not mature enough. If the “manual self-integration” means that the ordinary automatic transmission has the feel of a manual transmission, then the AMT transmission is just the opposite. It is based on the manual transmission. By changing the shift operation part, the overall structure is unchanged. In the case of adding an automatic control system to achieve automatic shifting, it is like a robot to complete the two actions of clutch and gear selection for you. Because it is still a manual transmission in nature, AMT also inherits the advantages of manual transmission in terms of fuel economy. During the driving process, the frustration caused by the gear change of AMT still exists. (2) Automatic transmission The automatic transmission uses a planetary gear mechanism to change the speed. It can automatically change the speed according to the change of the accelerator pedal and the speed of the vehicle. The driver only needs to operate the accelerator pedal to control the vehicle speed. Generally speaking, there are several types of automatic transmissions commonly used in automobiles: hydraulic automatic transmissions, hydraulic automatic transmissions, electric automatic transmissions, stepped mechanical automatic transmissions, and continuously variable mechanical automatic transmissions. Among them, the most common is a hydraulic automatic transmission. The hydraulic automatic transmission is mainly composed of a hydraulically controlled gear transmission system, mainly including an automatic clutch and an automatic transmission. It can automatically shift gears according to the opening of the throttle and changes in vehicle speed. Continuously variable transmission is a type of automatic transmission.
Divided by manipulation (1) Forced transmission: Forced transmission is based on the driver’s direct control of the shift lever to shift gears. (2) Automatically operated transmission: The transmission ratio selection and gear shifting of the automatically operated transmission is performed automatically, so-called “automatic”. It means that the change of each gear of the mechanical transmission is realized by controlling the actuators of the shift system with a signal system that reflects the engine load and vehicle speed. The driver only needs to manipulate the accelerator pedal to control the vehicle speed. (3) Semi-automatic transmission: There are two types of semi-automatic transmission: one is the automatic operation of several gears, and the remaining gears are operated by the driver; the other is a preselected type, that is, the driver uses The gear is selected by the button. When the clutch pedal is depressed or the accelerator pedal is released, an electromagnetic device or a hydraulic device is turned on to perform a gear shift.
The automatic transmission can automatically change the transmission ratio according to the engine load and vehicle speed, so that the car can obtain good power and fuel economy, and reduce engine emissions pollution. The automatic transmission is easy to operate and can greatly improve the safety and reliability of the vehicle when the vehicle is crowded.
The structure of the automatic gearbox is slightly more complicated than the manual gearbox, but its function is greatly improved. The automatic transmission uses a high-efficiency, high-reliability torque converter / planetary gear design. This design has withstood the test of heavy-duty conditions around the world in the past decades and is still continuously improving.
(1) Change the transmission ratio and expand the range of drive wheel torque and rotation speed to adapt to frequently changing driving conditions, while making the engine work under favorable conditions (higher power and lower fuel consumption); (2) Enable the car to run backwards with the engine rotating in the same direction; (3) Use neutral gear to interrupt power transmission so that the engine can start and change speed, and it is convenient for the transmission to shift gears or perform power output. (4) The transmission is composed of a variable-speed transmission mechanism and a steering mechanism, and a power take-off can be added when needed. There are two ways in classification: according to the change of transmission ratio and according to the difference in operation.