In-wheel motor technology is also called wheel-mounted motor technology. In-wheel motor technology is a motor embedded in the wheel wheel. The stator is fixed on the tire and the rotor is fixed on the axle. When power is supplied, the stator and rotor move relative to each other. The electronic phase commutator (switch circuit) controls the stator winding energization sequence and time according to the position sensor signal, generates a rotating magnetic field, and drives the rotor to rotate. Its biggest feature is that the power, transmission and braking devices are integrated into the wheel hub, thus greatly simplifying the mechanical part of the electric vehicle.

The technology of in-wheel motor is to install the motor in the wheel hub and directly drive the wheel without any transmission from the mechanical structure. It is essentially a direct drive motor. It's that simple. Its biggest feature is that the power unit, transmission device and braking device are all integrated into the wheel hub, which greatly simplifies the mechanical part of the electric vehicle.

The wheel hub motor drive system is mainly divided into two structural types according to the rotor type of the motor: inner rotor type and outer rotor type. The outer rotor type uses a low-speed external sub-motor. The maximum speed of the motor is 1000-1500r/min. There is no reduction device and the wheel The rotational speed is the same as that of the motor; while the inner-rotor type uses a high-speed inner-rotor motor and is equipped with a reducer with a fixed transmission ratio. In order to obtain higher power density, the rotational speed of the motor can be as high as 10,000r/min. With the advent of more compact planetary gear reducers, inner-rotor hub motors are becoming more competitive in terms of power density than low-speed outer-rotor types.

Advantages of hub motors:

1: The application of in-wheel motors can greatly simplify the structure of the vehicle. Traditional clutches, gearboxes, and drive shafts will no longer exist. A large number of transmission components are omitted, making the vehicle structure simpler and the vehicle suddenly seems to be much more spacious.

2: A variety of complex driving methods can be realized

Since the in-wheel motor has the characteristic of independent driving of a single wheel, it can be relatively easily implemented whether it is front-wheel drive, rear-wheel drive, or four-wheel drive. Full-time four-wheel drive is very easy to implement on a vehicle driven by an in-wheel motor.

Disadvantages of hub motors:

1: Although the quality of the entire vehicle has been greatly reduced, the unsprung mass has been greatly improved, which will have a huge impact on the vehicle's control, comfort and suspension reliability.

2: Cost issue, the cost of high conversion efficiency, lightweight four-wheel hub motor remains high.

3: Reliability issues. Putting a precision motor on the wheel hub will cause failure problems caused by long-term severe up and down vibration and harsh working environment (water, dust). We should also consider that the wheel hub is an easily damaged part in a car accident. High maintenance costs.

4: Braking heat and energy consumption issues. The motor itself generates heat. Due to the increase in unsprung mass, the braking pressure is greater and the heat is greater. Such concentrated heat requires high braking performance.

Since its establishment, Shenzhen Zhongling Technology Co., Ltd. has been focusing on the research of stepper motors and servo motors, and has obtained a number of patents and has rich experience. The stepper motors and servo motors produced by the company are also sold at home and abroad, becoming the best choice for many robot companies and many automation equipment manufacturing companies.