“The biggest benefit of the hub drive is energy saving. This method can save about 15% energy compared with the centralized drive. The second advantage is that it is easy to arrange low-floor buses, shuttle buses, etc., if there is no wheel drive or Where the hub drive system is vacant, low-floor models are difficult to achieve; third, the hub drive contributes a lot to the weight reduction of the entire vehicle, which can reduce the weight of the vehicle by at least 15%; in addition, it has a high reliability. Advantages, but also more conducive to the future realization of intelligent drive, intelligent driving technology. I think with the large-scale use of motor and control technology, plus the elimination of intermediate parts such as transmission, its cost should be further reduced." 2018 At the China Electric Vehicle Centennial Forum, when talking about the development status of the hub motor, Sun Fengchun, an academician of the Chinese Academy of Engineering and a professor at the School of Mechanical and Vehicle Engineering at Beijing Institute of Technology, introduced the reporter to the reporter. During the forum, He Junzheng, president of Hubei Tate Mechanical & Electrical Co., Ltd. (hereinafter referred to as “Tateâ€), also accepted an interview with the reporter. In his view, the hub motor as an ultimate solution has now reached the eve of industrialization.
Indeed, as Sun Fengchun said, in the context of the rapid development of intelligent networked vehicles, the development of hub-mounted electric wheel assemblies and wheel-side electric drives has become a representative of distributed drive products. The development of the past two years is worthwhile. It is noted that China's industrial M&A cases in wheel hub motors and electric wheels have begun to increase. Many companies have started joint ventures with foreign manufacturers, and in the commercial vehicle sector, Hubei Tete Mechanical & Electrical Co., Ltd. acquired a wholly-owned acquisition in 2016. An example of the Dutch e-TracTIon company.
â– The advantages of electric direct drive technology are obvious
In China, more than 90% of vehicle manufacturers choose the central motor drive route, which is also the most traditional way. The motor consists of an electric motor, a fixed speed ratio reducer and a differential. The transmission process is from the engine. Go to the drive shaft, pass the transmission, and finally reach the wheel. Although the wheel-side motor saves the engine and the drive shaft, since the motor is mounted on the vehicle body, it has a great influence on the layout control of the whole vehicle. The biggest feature of the hub motor is that the drive motor is installed inside the wheel, the output torque is transmitted directly to the wheel, and the mechanical transmission components such as the clutch, the reducer and the transmission bridge are discarded, which greatly simplifies the structure of the mechanical part of the automobile.
The simplified hub motor was compared to the chairman of Tate, Lu Chao, as “Alibaba in the retail industryâ€. “The hub motor reduces the intermediate link, and its benefits are improved reaction speed and reduced energy consumption. We have done experiments in China and found that the efficiency of the hub motor can reach 92% to 94%, which is 25% higher than that of the central motor, which means that In the electric vehicle, a quarter of the battery is installed, and the problem of lightweighting of the vehicle will be solved. As we all know, a large part of the cost of electric vehicles is in the power battery part, and the cost of the hub motor decreases with the fiscal subsidy policy. The advantages will gradually emerge, so we are the most hoped companies to subsidize the decline." He Junzheng told reporters. He expects that once the hub motor is used in large-scale applications in the future, the traditional transmission parts, clutches and other auto parts companies and even the upstream machine tool enterprises will be subject to subversive effects.
He Junzheng introduced: "The direct drive characteristics of the hub motor can not only reduce the noise of the vehicle, but also optimize the acceleration and smoothness, so that the comfort aspect of the vehicle is also improved." The hub motor mentioned in Sun Fengchun will help the intelligent network. In terms of automobile development, He Junzheng explained: "Because the mechanical link between the motor and the wheel is reduced, the drive system and the actuator are placed together, and the information can be directly transmitted to the actuator of the entire vehicle, that is, the wheel, which makes the control signal of the vehicle More accurate and direct. In the future, intelligently driven vehicles must add a lot of components. The increase of components means an increase in power consumption. If the power system can save power, it can compensate for the losses caused by the operation of the intelligent driving system. Lu Chao revealed that e-TracTIon is developing related research on driverless technology.
â– Industrialization test water steadily advances
In fact, the hub motor has already been operated in more than 10 pure electric commercial vehicle transportation routes in 8 countries in Europe. The earliest batch began in 2009. Tate has conducted energy consumption tests in both European and domestic urban road conditions. According to He Junzheng: "For the same 12-meter full-load pure electric bus, the power consumption test results under European urban road conditions are: central motor 1.06 degrees / km, wheel motor 1.04 degrees / km, hub motor 0.91 degrees / km. In the domestic urban working environment, a 17.78-ton city bus with a hub motor drive system, at no load and full load The power consumption is 0.56 degrees / km and 0.67 degrees / km."
It has been more than a year since it entered the domestic market. Tate's development is very rapid, and it hopes to cut into the wheel motor technology from the commercial vehicle market. At present, it has reached cooperation with many domestic OEMs. For the reporter's high manufacturing cost problem, Lu Chao believes: "The hub motor device provides the entire system including tires, drive axles, and motors, which is equivalent to the majority of the chassis of the car, plus the number of batteries can be reduced and repaired. The low cost, so the overall cost is 11% lower than the central motor." He hopes to reduce the market price of the hub motor by one-third in the future.
“In terms of commercial vehicles, there is no second company in the current hub motor, so our biggest competitor is still the traditional central motor and wheelside motor. The electrification of the car makes the hub motor have the applicable conditions. I think this is also a result of the overall improvement of the whole society's technology." Lu Chao finally said.
Wuxi Doton Power , http://www.dotonpower.com