A large number of transmission parts are omitted, which makes the vehicle structure simpler.
For traditional vehicles, clutches, transmissions, transmission shafts, differentials and even transfer gears are all essential, and these components are not only light in weight, which makes the structure of vehicles more complicated, but also have problems of regular maintenance and failure rate. But the hub motor solves this problem very well. In addition to the simpler structure, the vehicle driven by hub motor can also obtain better space utilization and higher transmission efficiency.
Folding can realize a variety of complex driving modes.
Because the in-wheel motor has the characteristics of single-wheel independent drive, it can be easily realized in the form of front drive, rear drive or four-wheel drive, and it is very easy to realize full-time four-wheel drive in a vehicle driven by in-wheel motor. At the same time, the hub motor can realize differential steering similar to that of a tracked vehicle by rotating the left and right wheels at different speeds or even reversely, which greatly reduces the turning radius of the vehicle, and can almost realize in-situ steering under special circumstances (but the steering mechanism and tires of the vehicle are greatly worn at this time), which is very valuable for special vehicles.
It is convenient to adopt various new energy vehicle technologies.
Many new energy vehicles are driven by electricity, so the hub motor drive comes in handy. Whether it is pure electric vehicle, fuel cell electric vehicle or extended-range electric vehicle, hub motor can be used as the main driving force; Even if it is a hybrid car, the hub motor can be used as a boost when starting or accelerating rapidly, which can be described as a multi-purpose machine. At the same time, many technologies of new energy vehicles, such as braking energy recovery (i.e., regenerative braking), can also be easily implemented on in-wheel motor-driven vehicles.
Disadvantages of hub motor
Increasing the unsprung weight and the moment of inertia of the hub will affect the handling of the vehicle.
For ordinary civil vehicles, some relatively light materials, such as aluminum alloy, are often used to make suspension parts to reduce unsprung weight and improve the response speed of suspension. However, the hub motor just greatly increases the unsprung weight and the rotational inertia of the hub, which is unfavorable to the handling performance of the vehicle. But considering that most electric vehicles are limited to riding rather than pursuing dynamic performance, this is not the biggest defect.
The electric braking performance is limited, and it needs a lot of electricity to maintain the operation of the braking system.
At present, many traditional power commercial vehicles have been equipped with auxiliary deceleration devices using eddy current braking principle (that is, resistance braking), such as electric retarder used by many trucks. Because of energy, electric braking is also the first choice for electric vehicles. For the vehicle driven by in-wheel motor, because the electric braking ability of in-wheel motor system is small, it can not meet the requirements of vehicle braking performance, and all of them need additional mechanical braking system. But for ordinary electric passenger cars, there is no vacuum pump driven by traditional internal combustion engine, and electric vacuum pump is needed to provide braking assistance, but it also means greater energy consumption. Even if regenerative braking can recover some energy, if the braking system is to ensure its efficiency, the braking system will
In addition, the working environment of hub motor is relatively harsh, affected by water, dust and other aspects, and it also has high requirements in sealing. At the same time, the heat dissipation of hub motor needs to be considered separately in the design.