Application of axial flux motor
Axial flux motor (also called "disc motor") has a different flux path from ordinary radial motor. The air gap is planar and the direction of the air gap magnetic field is parallel to the motor axis. The core technical advantage of axial flux motor is that the rotating rotor is located on the side of the stator (rather than inside the stator), so the rotor has a larger diameter, and torque = force × radius, so it can obtain higher torque output under the same force. This means that higher torque output can be obtained under the premise of providing the same permanent magnet material and copper wire material. Generally, the design using the new axial flux motor can improve the torque density by more than 30% compared with the design using the traditional radial flux motor.
In the field of automotive electric drive using permanent magnet synchronous motor or induction motor, the traditional radial flux motor is being widely developed for weight and cost optimization, but the room for further improvement of the technical level is very limited. Therefore, turning to a completely different type of motor may be a good alternative. Due to the technical characteristics of axial flux motors, such as compact structure, flat and ultra-thin, small size, light weight, and high power density, many developers have worked hard to improve the technology in the past decade to make it gradually suitable for new application scenarios such as electric motorcycles, airport pods, cargo trucks, electric vehicles, and even electric aircraft.
1. The topological structure combination of axial flux motors is flexible and can be combined according to the actual application scenario.
According to the stator-rotor combination structure, axial flux motors can be divided into the following four structures:
1. Single stator/single rotor structure:
1 rotor + 1 stator, simple and compact structure, but large unilateral magnetic pull, large bearing load, large vibration and noise, and risk of stator-rotor friction, which reduces the life of the motor;
2. Single stator/double rotor structure:
2 outer stators + 1 inner rotor, high power density, more suitable for traction systems, aerospace and other fields;
3. Double stator/single rotor structure:
2 outer rotors + 1 inner stator, with good symmetry, relatively small unilateral magnetic pull, more suitable for wind power generation systems;
4. Multi-stator/multi-rotor structure:
multiple stators + multiple rotors, suitable for high torque scenarios, such as ship propulsion systems, large wind power generation and hydropower generators.
2. Limitations of axial flux motors
1. Cost issues:
Axial flux motors require special materials and manufacturing processes, so the manufacturing cost is usually higher than that of traditional radial flux motors. For example, the use of yokeless topology and special stator-rotor design will increase costs.
2. Complexity of design and production:
The design and production of axial flux motors are usually complicated. For example, the air gap between the rotor and stator needs to be kept uniform. The axial force during operation may cause severe tension on the motor shaft. The manufacturing process and mechanical equipment are not as mature as those of radial motors. These all limit the ability of large-scale production.
3. Heat dissipation problem:
Since the windings of axial flux motors are located deep in the stator and between the two rotor disks, heat dissipation is very difficult. The motor will overheat when running under high load, affecting the performance and life of the motor.
Ningbo Nide Mechanical Equipment Co., Ltd., was established in 2010, committing to provide customers with highly automated, intelligent, and flexible motor manufacturing solutions, and focusing on the production line of stator, rotor and final assembly of various motors.
We provide customers with a variety of automotive brush motor manufacturing solutions, and provide customers with axial flux motor and longitudinal flux motor manufacturing equipment, including induction motor manufacturing, disc motor manufacturing, series motor manufacturing, and brushless motor manufacturing.