Third, the wheel motor drive mode
(1) Deceleration drive
This drive mode uses a high-speed inner rotor motor and a fixed gear ratio reducer. The power density is relatively high, and the motor can reach a maximum speed of 10 kr/min.
Advantages: high specific power and efficiency, small volume and light weight; the torque of the deceleration structure makes the output torque larger and the climbing performance is good; it can ensure that the car obtains a large smooth torque at low speed.
Disadvantages: It is difficult to achieve lubrication. The gears of planetary gear reduction structure wear faster, the service life is relatively shorter, it is not easy to dissipate heat, and the noise is relatively large.
(2) Direct drive
The driving method adopts a low-speed outer rotor motor, and the outer rotor of the motor is directly connected with the hub. The rotation speed of the motor is generally about 1.5Kr/min, and there is no deceleration structure, and the rotation speed of the wheel is consistent with the motor speed.
Advantages: Since there is no speed reduction mechanism, the structure of the entire driving wheel is more compact, the axial dimension is smaller than that of the former driving type, and the transmission efficiency is higher.
Disadvantages: 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.
