03Classified by driving mode
When driving directly, the motor mostly adopts an outer rotor structure, that is, the rotor directly drives the hub to rotate, so the speed is low. Corresponding to this, in indirect drive, the motor is mostly an inner rotor structure with a higher speed. The planetary gear plus ring gear is used to achieve deceleration and drive the hub to rotate, so it is also called deceleration drive.
04 Classified by rotation speed