Most electric vehicles (electric cars, electric bicycles, and wheelchairs) use on-board batteries and a fairly ordinary electric motor to power two or four wheels. But some of the latest electric cars and electric bicycles work differently. Instead of letting a motor use gears or chains to power all wheels, they build a motor directly in the hub of each wheel, so the motor and the wheel are the same thing, which is what we call a hub motor.
The biggest difference between the wheel motor and the electric bicycle hub motor is that the motor rotor of the wheel hub motor is the hub itself, and the hub and the motor of the wheel motor are separated.
Electric bicycle hub motor: The hub motor means that the motor rotor itself is the hub, and tires are installed on the rotor. In-hub motor technology, also known as in-wheel motor technology, integrates power, transmission and braking devices into the hub. To put it bluntly, the most important thing is to install an "engine" inside the wheels, but this engine is electrically driven and independent.
Wheel motor: The wheel motor means that the hub and the motor are separated, but the motor is installed next to the wheel and directly drives the wheel with or without deceleration.
There are usually two ways of wheel motor drive: in hub electric motor and in-wheel motor in a narrow sense. The so-called wheel-side motor in a narrow sense means that each driving wheel is driven by a separate electric motor, but the electric motor is not integrated in the wheel, but is connected to the wheel through a transmission device (such as a drive shaft). The drive motor of the wheel motor mode belongs to the range of sprung mass, and the suspension system has good vibration isolation performance. However, the electric vehicle motor installed on the body has a great influence on the overall layout of the vehicle, especially in the case of rear axle drive. Moreover, due to the large deformation movement between the vehicle body and the wheels, there are also certain restrictions on the universal transmission of the drive shaft.
In fact, the principle of an electric bicycle hub motor is no different from that of a traditional motor, but the structure is more complicated, which means that there are fewer coils and the magnetic field is not as strong as a traditional motor, so the output power is relatively small. In addition, there are two types of hub motors: inner rotating motors and outer rotating motors, where the rotor of the outer rotating motor is located inside the stator, just like a traditional motor. The rotor of the external rotating electric machine is located outside the stator and rotates around the stator. The hub motor integrates the power unit, transmission and braking device into the hub, which greatly simplifies the mechanical part of the electric vehicle.