For a medium-powered bicycle, the motor power take-off shaft and the crankshaft of the bicycle are structurally two shafts, and the middle is linked by a speed reduction mechanism. According to the difference between the relative positions of the two axes, the center motor can be divided into a coaxial motor (also called a concentric motor) and a parallel axis motor.
Advantages of coaxial motors
Coaxial motor, as the name implies, is the crankshaft shaft and the power output shaft of the motor are on the same axis. These motors are mostly outer rotor motors. The inner ring of the motor stator and the space on both sides are used to position the deceleration system. Therefore, the coaxial motor The appearance looks smaller and the internal structure is more compact.
However, in a limited space, it is not easy to achieve multi-stage deceleration, while also taking into account the torque, heat dissipation and ensuring the concentricity of the drive shaft.