Easy to understand the hub motor
Why did Tesla dismantle the outer casing and only the chassis is still like a craft, and can also make room for two large luggage compartments? The more widespread interpretation of the folks is said: "Tesla has strong integration capabilities, they use wheel motors."
The answer just seems to have some truth. But there is a more serious mistake in this answer. Can the Tesla electric drive system be placed between the two wheels of the rear axle? On this misunderstanding, let's talk about what is a wheel motor, a hub motor, and a centralized motor.
Hub motor
Wheel hub motor technology is also known as wheel built-in motor technology. Because the hub motor has the characteristics of independent driving of a single wheel, it can be easily realized in the front, rear or four-wheel drive form. The full-time four-wheel drive is driven by the hub motor. It is very easy to implement on the vehicle. At the same time, the hub motor can realize the differential steering of the similar track-type vehicle through different speeds of the left and right wheels or even reverse, greatly reducing the turning radius of the vehicle, and can realize the in-situ steering in special cases. This skill is quite valuable for special vehicles. Therefore, this technology is mostly used in special vehicles such as mining cars, engineering vehicles and so on.
Moreover, the application of the hub motor can greatly simplify the structure of the vehicle, and the conventional clutch, gearbox and transmission shaft will no longer exist. This also means saving more space. More importantly, the hub motor can be used in parallel with conventional power, which is also very meaningful for hybrid vehicles.
However, no vehicle in the mass-produced passenger vehicles in the market uses this technology. It is not a few meanings to say that there are so many advantages in production cars! The reason is that some of its drawbacks will make it a little acclimatized in the use of passenger cars, the hub motor should be installed in the rim, which makes the unsprung mass of the vehicle increase first problem is not conducive to manipulation; the second point eddy current The braking capacity is not high, and it needs to work together with the mechanical brake system on the heavy-duty vehicle.
For electric vehicles, it takes more energy to achieve higher braking effect, which affects the cruising range to a certain extent. Third, if the power output is slightly different, the direction control of the vehicle in high-speed driving is also It will cause a loss of control that is magnified several times. Moreover, it is difficult to achieve lubrication, which will cause the gear of the planetary gear reduction structure to wear faster and have a shorter service life, and it is not easy to dissipate heat, and the noise is not good. In the case of starting, top wind or climbing, etc., it is necessary to carry a large current, which is easy to damage the battery and the permanent magnet. The peak area of the motor efficiency is small, and the efficiency drops rapidly after the load current exceeds a certain value.
In summary, the combination of the hub motor and the mass production passenger car is still a story of joy and sadness.
