Shenmao Capacitors specialized in aluminum electrolytic capacitors from 1970

New energy vehicles don’t need a gearbox? Not only is it necessary, it is also very complicated!

by:Shenmao     2021-07-08
More industry information can be found at www.transmission system has undergone tremendous changes in the era of new energy vehicles. Since the electric motor has a wide and efficient working range, only need to adjust the input current to complete the control of the output power and realize the acceleration and deceleration of the vehicle. This makes the gearbox, which has always been regarded as a key component, 'superfluous'. Traditional cars are constantly chasing higher speeds, but most electric cars only need a single-stage reducer to complete the power transmission from the motor to the wheels. Why is there a saying that electric cars do not need to be equipped with a gearbox? The driving power source of an electric vehicle is an electric motor. Compared with an engine, an electric motor has a difference, that is, in a constant power state, the slower the speed, the greater the torque; the higher the speed, the smaller the torque. Therefore, when the power supply of the electric vehicle to the driving motor is constant, that is, constant power input, the motor can automatically output the torque required by the electric vehicle to overcome the resistance, and the maximum speed under the resistance can be obtained. From the point of view of the acceleration process, that is, at each point in the acceleration, the motor always automatically reduces the torque in exchange for the highest speed at that point in time. In this way, the motor itself has the characteristics of a gearbox, without the need for an external gearbox, so that the wheels of electric vehicles can flexibly and automatically output different torques according to the vehicle conditions to overcome forward resistance. So, here comes the question: Does electric car really need a gearbox? The gearbox can be omitted, but it does not necessarily mean that the gearbox is not necessary; without the gearbox + clutch, an electric car can complete the basic functions of driving; but if the electric car is matched with a transmission + clutch, it can be even more powerful and icing on the cake. At present, some international giants have already smelled this market opportunity. Famous international component suppliers such as GKN, Schaeffler, and BorgWarner have developed mass-produced AMTs, and some plug-in hybrid models of BMW and Toyota are also equipped with multi-stage gearboxes; domestic rise A group of electronic control companies are rookies, and some companies that are transforming from traditional gearboxes are also planning their layout. The core configuration of the new energy vehicle is the electric motor. The biggest difference compared with the engine is that the power of the electric motor is constant, the torque required to overcome the resistance, and the maximum speed under the resistance can be obtained. The motor itself has its own variable speed. The properties of the box, so no additional equipment is required? Do all new energy vehicles do not need a gearbox? At present, new energy vehicles in series, pure electric, and fuel cells currently mostly use single-stage reducers. In the future, energy consumption requirements will increase, or they may develop into multi-stage reducers; in parallel, existing automatic gearboxes are mostly used for transformation or electric drive axles; Liando adopts a dedicated hybrid gearbox. In general, new energy vehicles still need gearboxes. In recent years, two-speed transmissions, coaxial transmissions, transmissions with integrated electronic disconnection differentials, transmissions with integrated dual-clutch differentials, and electric motor controller transmissions have emerged in recent years. A new type of transmission such as an assembly, a transmission with integrated engine, motor and generator. 1 Two-speed transmission GKN (GKN) two-speed transmission, the reduction ratios are 11.38 and 5.85 respectively. Figure 1 is a cross-sectional view of the GKN two-speed transmission, and Figure 2 is the shift mechanism of the GKN two-speed transmission on the input shaft. Used in BMW i8 hybrid vehicles. Getrag has a two-speed transmission with reduction ratios of 12.06 and 8.61 respectively. Compared with the single-speed transmission with a reduction ratio of 9-10.5, the low-speed gear reduction ratio of the two-speed transmission is set to 11-12, which meets the acceleration and climbing performance, and the maximum motor torque required can be reduced; the high-speed gear reduction ratio setting It is 5-9, which meets the requirements of the maximum speed, and the maximum speed of the motor required can be reduced. The maximum torque and maximum speed of the motor are reduced, which can make the motor smaller and lighter. In addition, the two-speed transmission allows the motor to run more at the best efficiency point, reducing fuel consumption. Fig. 1 Sectional view of GKN two-speed transmission Fig. 2 Shift mechanism of GKN two-speed transmission on the input shaft 2 Coaxial transmission GKN transmission, the input shaft and the output shaft are coaxial. Figure 3 is a cross-sectional view of GKN coaxial single-speed transmission. Applied to Volvo XC90 T8 hybrid electric car. Chevrolet Bolt transmission, the input shaft and output shaft are coaxial. Figure 4 is a cross-sectional view of the Chevrolet Bolt coaxial single-speed transmission. Used in Chevrolet Bolt pure electric vehicles. The input shaft and output shaft coaxial structure can reduce the size of the transmission and facilitate the layout of the whole vehicle. Fig. 3 Sectional view of GKN coaxial single-speed transmission Fig. 4 Sectional view of Chevrolet Bolt coaxial single-speed transmission 3 Transmission with integrated electronic disconnection GKN transmission, integrated electronic disconnection differential. Figure 3 is a cross-sectional view thereof. Figure 5 is an exploded view of GKN electronic disconnect differential.
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