Magnetic steel demagnetization solution

The hub motor is generally a surface-mounted rotor structure, and the magnetic steel directly faces the air gap magnetic field and is easily demagnetized. To improve this problem, we need to learn from the development path of centralized motors. It is a transition from a surface-mount to an interpolated rotor structure, from a single-layer structure to a two-layer structure. After the magnetic steel is buried in the iron core, the iron core can play a role in bypassing the demagnetizing magnetic field, and does not allow the permanent magnet to directly face the demagnetizing magnetic field.

The following is an 80kw outer rotor hub motor. The pole structure is SPOKE structure. The magnetic steel is arranged in a tangential direction, and the anti-demagnetization capability is higher than that of the surface mount structure.

For the inner rotor structure, it is easier to realize the interpolated structure. The figure below is a 35kw hub motor developed by Hanyang University. It adopts a U-shaped magnetic pole structure and has high anti-demagnetization capability.

Motor cost solution

The cost solution for hub motors is similar to the centralized drive motor method. Less rare earth, no rare earth, and high speed are all feasible directions. Some people are already developing ferrite disc hub motors, which can significantly reduce the cost of the motor. (Limited to the length, not expanded.)

to sum up

Hub motor is a hot spot in current EV drive technology. We can clearly feel the strong demand for this technology, but there are also various technical bottlenecks that have yet to be broken. Challenges and opportunities coexist. In this complicated and entangled situation, some people are gearing up, some people are in the night, and more people are watching. Qingshan can't cover it. After all, any technology has its development process. In the process, the meaning of my work is to make more people see more clearly and see more clearly.