Application and advantages of axial flux motor manufacturing technology
Market application of axial flux motor
Currently, axial motors are widely used in new energy vehicles, robots, aerospace, ship propulsion, wind power generation and other occasions that require high torque density and compact space.
New energy vehicles are an important market for large-scale application of axial motors
The small size and low theoretical cost of axial flux motors are expected to solve the cost and volume problems of wheel-side motors and promote the large-scale application of wheel-side motors. The power density advantage of axial flux motors can output sufficient torque while maintaining lightweight and reducing unsprung mass, promoting the mass application of hub motors. Axial flux motors have played an important role in the performance and design optimization of commercial vehicles. Commercial vehicle electrification is a new blue ocean for axial flux motors.
High-end precision robots
High-end robots have the following requirements for joint drive motors: rapidity. The time from the motor obtaining the command signal to the completion of the working state required by the command should be short; the starting torque inertia ratio should be large. In the case of driving load, the robot joint motor is required to have a large starting torque and a small moment of inertia; small size, small mass, and short axial size; able to withstand harsh operating conditions, can perform very frequent forward and reverse and acceleration and deceleration operations, and can withstand overload in a short time. Providing high peak torque and high response speed high-power thrust under the premise of millimeter-level thickness, the performance requirements that are difficult to achieve with radial motors accurately hit the advantage range of axial motors.
Aerospace
Lightweight and compact, the power density is adapted to the requirements of aviation electrification. The axial motors currently carried by fixed-wing aircraft have a propulsion power of up to 400KW.
Ship propulsion
Optimize the drive structure of electric ships and save energy and reduce consumption. Axial motors have significant advantages in improving ship efficiency, reducing emissions, and optimizing structures. The natural high torque density means higher power conversion efficiency and more compact structural design than traditional motors, which is crucial for optimizing ship propulsion systems and saving energy and reducing consumption.
Introduction to axial flux motors
The air gap of axial flux motors is planar, the axial length is short, and it is a thin disc shape, so it is also called a disc motor.
The topological structure combination of the axial flux motor is flexible and can be combined according to the actual application scenario. According to the stator-rotor combination structure, the axial flux motor can be divided into the following four structures:
Single stator/single rotor structure: 1 rotor + 1 stator, the structure is simple and compact, but the unilateral magnetic pull is large, the bearing load is large, the vibration noise is large, there is a risk of stator-rotor friction, and the motor life is reduced;
Single stator/double rotor structure: 2 outer stators + 1 inner rotor, high power density, more suitable for traction systems, aerospace and other fields;
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;
Multiple stators/multiple rotors structure: multiple stators + multiple rotors, suitable for large torque scenarios, such as ship propulsion systems, large wind power generation and hydropower generators.
According to the direction of the magnetic flux path, the motor can be divided into axial flux motors and radial flux motors. Although the magnetic flux directions are different, the working principles all follow the basic laws of electromagnetism. That is, the motor driver controls the magnetic field strength and direction of the coil (rotor) by changing the direction and magnitude of the current passing through the coil (rotor). Since the magnetic poles of the stator are fixed, when the magnetic field direction and strength of the rotor change, the magnetic field interacts to generate the Lorentz force, thereby driving the rotor to rotate.
The magnetic poles of the stator of the axial flux motor are arranged along the axis. The rotor is usually a cylindrical structure. The magnetic flux passes through the central axis of the rotor. When the current passes through the winding of the stator, the generated magnetic field passes through the rotor along the axis. According to the Lorentz force law, this magnetic field will generate torque in the rotor, thereby driving the rotor to rotate.
Advantages of axial flux motors
High efficiency:
Thanks to the shorter one-dimensional flux path, the efficiency of axial flux motors is very high, usually exceeding 96%, which is comparable to or better than the best two-dimensional radial flux motors on the market. Axial flux motors save about 15%-25% energy than ordinary radial motors at all power levels and can maintain peak power output for a longer time.
Small size and light weight:
The volume and mass of the axial flux motor can be half of those of the ordinary radial flux motor for automobiles. The axial flux motor is in line with the trend of lightweight automobiles. At the same time, it has a compact structure, a shorter radial length, and a high degree of installation freedom.
High torque density & power density:
The effective magnetic surface area of the axial flux permanent magnet motor is located on the surface of the motor rotor, not the outer diameter, so it can usually provide greater torque within a certain volume, thereby improving the torque density and power density.
Energy saving and carbon reduction:
The volume and weight advantages of the axial flux motor can reduce the consumption of copper, iron, permanent magnets and other materials in the production and manufacturing process by about 50% compared with the radial permanent magnet motor. If the coreless PCB stator technology is considered, the copper consumption of the axial motor can be reduced to 34% of that of the radial motor.
Low noise and vibration:
Due to the uniform distribution of the magnetic field, the axial flux motor generates lower noise and vibration during operation, which is especially suitable for application scenarios with strict requirements on noise and vibration.
At the same time, it has a smaller dead weight and higher efficiency. In the application, the motor consumes less power and has stronger driving ability, which is conducive to energy saving and carbon reduction.
Limitations of axial flux motors
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 a yokeless topology and a special stator-rotor design will increase costs.
Design and production complexity:
The design and production of axial flux motors are usually more 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, and the manufacturing process and mechanical equipment are not as mature as radial motors, which limits the ability to mass produce.
Heat dissipation problem:
Because 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.
NIDE Group can provide customers with optimized motor manufacturing solutions according to customer needs, reduce the failure rate of motors, and improve the market competitiveness of motor manufacturers.
We have provided customers with a variety of motor automation manufacturing solutions, including axial flux motor manufacturing line, alternator motor automatic production line, hairpin motor stator and rotor assembly line, oil pumps motor stator production line, single-phase motor winding machine, stator wire binding machine, stator shaping machine, motor rotor production line, rotor shafting machine, rotor winding machine, etc. to meet customers' high-efficiency and low-manpower motor manufacturing needs.