What is axial flux motor?
The motor can be divided into axial flux type and radial flux type according to the direction of the magnetic field. The world’s first motor was invented by Michael Faraday on 1821. Actually, Faraday motor belongs to axial flux motor, but the further development of axial flux motor was limited by the material and technological level at that time. Conversely, the radial flux motor which invented by Davenport on 1834 taking the lead in development, and became known as the simple motor.
Axial flux motor & radial flux motor
The air gap of axial flux motor is planar, and its air gap magnetic field distribution along the axial direction, that is, the air gap magnetic field is perpendicular to the air gap plane. The current development trend of the motor is high speed, low weight and high efficiency, and the axial flux motor is regarded again under this circumstance.
Advantages of axial flux motor
Compact structure, especially short axial sizes.
High torque density.
High power density.
Excellent cooling performance.
Application of axial flux motor
Based on the above advantages, axial flux motor is perfect for high torque density and space compact applications. Most people believe that the high power density only depends on high speed, and overlook the influence of torque density. The mere pursuit of high speed will lead the short service time and noise. In fact, the core of the high-speed motor is the enhancement of torque density, and axial flux motor is a typical solution among them.
About Axial flux motor magnet
Stanford Magnets Team has been collected a lot of useful experience on axial flux motor magnet during these years. Here below two simple solutions for axial flux motor magnet:
a. Axial flux motor magnet with skewed fan shape
For the slotted motor, the cogging torque cannot be avoided due to the interaction between the permanent magnet and the stator tooth, hence lead to torque ripple, vibration and noise. The cogging torque of axial flux motor will be suppressed after changing the traditional fan shape axial flux motor magnet into skewed fan shape.
b. Laminated type axial flux motor magnet
Axial flux motor is also suffering from eddy current losses, and its work efficiency will be also affected by the high-temperature demagnetization. Magnet segmentation technique is an advisable choice to decrease the eddy current losses of axial flux motor magnet. It should be noted that the effects of horizontal segmentation will be much better than vertical segmentation’s.