Text/Qin Ming
As one of the important accessories of the car power, the gearbox cannot exert strong power even if there is a powerful engine and does not match a suitable gearbox. The engine is equivalent to the heart of the car, while the gearbox is equivalent to the blood vessels and nerves, controlling the size of the transmission force, which is mainly used to change the engine speed and torque of the device, more different working conditions to distribute the change of the output shaft and the incoming shaft transmission ratio, and the engine force to the wheel. For example, a larger torque is required for the uphill slope, and if the engine power is unchanged, it is necessary to sacrifice the speed to obtain more torque, and the gearbox is responsible for this task. In simple terms, the engine is like a reckless man who only exerts force, and the gearbox is a device that helps the engine to punch faster and sometimes punch harder.
The gearbox is mainly composed of two parts of the transmission mechanism and the control mechanism, the transmission mechanism is mostly driven by ordinary gears, and some are driven by planetary gears, such as Toyota's world-renowned Toyota THS hybrid system, and its matching E-CVT transmission is to use a set of planetary gear sets as the core. The operating mechanism is also very different according to the type of gearbox, and it is carefully analyzed in the rear of various gearboxes and then supplemented.
Cars will encounter different working conditions during the driving process, there are uphill and downhill, starting to reverse, idling high speed These situations require vehicles to have different speeds and torques, and it is not enough to rely on the engine alone. Need the gearbox to adjust the speed and torque of the engine, by changing the gear ratio, so as to expand the torque and speed change range of the driving wheel, take the bicycle to the gear shift example, there are small gears to large gears 6 kinds of gears, if the front gear is larger than the rear gear, the front gear 1 turn, the rear gear can turn two turns, then the speed of the rear gear increases, on the contrary, the front gear turns two turns, the rear gear only turns a turn, the speed slows down and twists naturally.
Of course, the structure and working principle of each transmission are also very different, take the simplest manual transmission to illustrate, the engine output rotates the input shaft, the input shaft is connected to the intermediate shaft through the gear, and the intermediate shaft drives the output shaft to rotate, and the output shaft can change the size of the gear by moving forward and backward, so as to adjust the output shaft Low speed and high speed Two power forms. As the number of gears increases, the working principle is the same, but the number of gears on the output shaft is increased, and more gears of different sizes bring more torque speed options. The automatic transmission works by changing the gear ratio, but the structure is more complex.
The gearboxes on the market are various, with different names, different principles, and different components, but they are all gearboxes derived from 5 types of gearboxes. There are roughly 5 categories of transmissions on the market, manual transmission (MT), manual transmission (AMT), automatic transmission (AT), stepless transmission (CVT), dual clutch transmission (DCT), naturally they have different advantages and disadvantages and scope of application, such as the current AT and CVT in ordinary cars are widely used and sought after.
First do not rush to analyze the structure and principle of these five types of gearboxes, first roughly understand these five types of gearboxes, see what advantages and disadvantages they have, which one are you more inclined to?
Let's start with the simple MT manual transmission, which is commonly known as the manual transmission, which is mainly composed of a gear lever, input shaft, intermediate shaft, output shaft, clutch, fitter and gear. By manipulating the shift lever, the shift mechanism connects the adapter to the corresponding gear, thereby driving the output shaft to rotate.
Although the working principle and structure of the manual gear is relatively simple, but also reliable, and the cost is low, the loss is small, and the manual gear can bring the most direct acceleration feeling, for those who love to drive, frequent gear changes, the natural structure is simple to bring the advantages of reliability and low cost, common in cheap cars and low-end cars, in addition to the transmission loss is small, compared to AT to save fuel, manual transmission to provide the most original driving experience, so welcomed by people who like to drive. However, the manual transmission operation is complicated and requires the driver to frequently step on the clutch to change gears, and it will be very difficult when encountering traffic jams.
Dual-clutch transmission as the name suggests is that there are two clutch transmissions, by the two clutches respectively control odd gears and even gears, on the whole and MT is more similar, when shifting gears, directly disconnect a clutch and then access to another clutch can complete the shift, and it can predict that you will upshift or downshift, in advance the fitter stuck gear, so the shift is very rapid transmission direct, power loss is smaller than at this stage, reliability is still worrying, and to do the shift without setbacks, you need a very careful teaching, In addition to being installed on ordinary models, this type of speed box is often installed in some supercars.
AT automatic transmission, is a very widely used transmission today, with a torque converter to replace the clutch structure of traditional MT, by stirring the liquid to achieve semi-linkage, the transmission gear using a planetary gear group structure.
AT gearbox shift smooth, and do not need to carry out frequent gear shift operations, will automatically match gears according to the speed of the gear, simple and convenient easy to get started shortcomings, but because the structure is also more complex in all gearboxes, the need for high-precision parts, so the production difficulty is also high cost, but with the progress of science and technology, the current 8AT, 9AT has been able to take into account the performance and smooth, but certainly the price is more expensive, and there are only some luxury performance cars.
AMT gearbox, hand-integrated gearbox, this transmission is actually modified with MT, add a set of electronic control system and the like on the MT gearbox, is also the cheapest of all automatic transmissions, transmission loss is small but slow to shift gears, and the gear shifting setback is very obvious, so basically see not much.
CVT continuously variable transmission is also a gearbox type with a wide range of applications. This transmission is composed of two pairs of variable diameter discs and a steel belt, one of which is connected to the engine, the other is connected to the drive wheel, connected by a steel belt chain, and the purpose of speed change can be achieved by tightening and opening the disc, thereby changing the diameter of the steel belt transmission on both sides.
The structure is simple, the size is small, because there is no gear, the gear shift is linear, and there will be no frustration when changing speed. Because it is steplessly variable, the engine can be kept at the most suitable output speed at any time according to the needs of the vehicle; combined with the two points mentioned above, this gearbox is also the most fuel-efficient. However, because the gearbox has been working, the loss is also very high, and the transmission steel belt is limited, which is not suitable for too intense driving.
Overall, the 5 types of gearboxes have their own skills and areas of expertise, but as far as ordinary models are concerned, the AT gearbox is more balanced and practical, and the AT gearbox is also the best in the market, favored by the majority of users.