Axial flux motors, as a type of efficient and compact motor, have broad application prospects in electric vehicles, aerospace, and other fields. The stator core, as a key component of axial flux motors, requires optimized and innovative manufacturing processes to improve motor performance. The manufacturing process of the axial flux motor stator core will be detailed below.
The stator core of an axial flux motor typically uses silicon steel sheets as raw material. Silicon steel sheets have advantages such as high permeability and low iron loss, which can effectively improve the efficiency and performance of the motor. When selecting silicon steel sheets, it is necessary to choose the appropriate grade and specifications based on the specific requirements of the motor, such as power, speed, and frequency. For example, for high-power, high-speed motors, low-loss, high-magnetic-induction silicon steel sheets can be selected; for low-power, low-speed motors, lower-cost ordinary silicon steel sheets can be selected.
Before using silicon steel sheets, they must undergo rigorous inspection to ensure their quality meets requirements. Inspection includes checking the thickness, hardness, surface flatness, and insulation coating quality of the silicon steel sheets. Tools such as micrometers, hardness testers, and flatness gauges can be used for measurement and testing. Simultaneously, the electromagnetic properties of the silicon steel sheets, such as iron loss and magnetic induction, also need to be tested to ensure they meet the requirements of the motor design.
Based on the design dimensions of the stator core, silicon steel sheets are cut into suitable shapes and sizes. Cutting methods include laser cutting and stamping cutting. Laser cutting has advantages such as high precision and good cutting quality, but it is more expensive; stamping cutting is less expensive, but its precision is relatively lower. During the cutting process, it is necessary to carefully control the cutting precision and surface quality to avoid defects such as burrs and cracks.
Cut silicon steel sheets are stacked in a specific order and orientation to form the basic shape of the stator core. The lamination process is a crucial step in core forming, directly affecting the core's performance and quality. During lamination, careful attention must be paid to the alignment and compression of the silicon steel sheets to ensure the core's dimensional and shape accuracy. Lamination can be performed mechanically or manually. Mechanical lamination is more efficient and precise, but the equipment cost is higher; manual lamination is less expensive, but its efficiency and accuracy are relatively lower.
To ensure the integrity and stability of the stator core, the stacked silicon steel sheets need to be welded. Welding processes can include argon arc welding and resistance welding. Argon arc welding produces high-quality welds with high strength, but is slower; resistance welding is faster and more efficient, but produces relatively lower-quality welds. During welding, it is crucial to control welding parameters such as welding current, voltage, and time to avoid defects such as incomplete welds and porosity.
After welding, the stator core needs to be shaped to meet design requirements in terms of size and shape. Shaping can be performed mechanically or hydraulically. Mechanical shaping uses molds and presses to shape the core, offering high precision; hydraulic shaping uses hydraulic cylinders to shape the core, providing greater force and is suitable for shaping large cores. During the shaping process, it is crucial to control the shaping force and deformation to avoid damaging the core.
To prevent short circuits in the stator core during operation, it needs to be insulated. The selection of insulation materials depends on the motor's operating environment and requirements, such as temperature, humidity, and voltage. Commonly used insulation materials include insulating varnish, insulating paper, and insulating film. Insulating varnish has good insulation and heat resistance properties, making it suitable for insulation treatment of various motors; insulating paper and insulating film have high mechanical strength and insulation properties, making them suitable for motors with high insulation requirements.
The selected insulating material is coated onto the surface of the stator core to form an insulating layer. Insulation coating processes can include immersion and spraying. Immersion involves soaking the core in insulating varnish, allowing it to fully penetrate the core's interior and surface. Spraying involves using a spray gun to evenly apply the insulating varnish to the core's surface. During the coating process, it is crucial to control the coating thickness and uniformity to ensure the quality and performance of the insulation layer.
After coating with insulating material, the iron core needs to be dried to cure the insulation. Drying can be performed using methods such as oven drying or infrared drying. Oven drying offers uniform temperature and good drying effect, but takes a long time; infrared drying is fast and efficient, but the temperature distribution is uneven. During the drying process, it is crucial to carefully control the drying temperature and time to avoid overheating or over-drying the insulating material, which could affect its insulation performance.
The winding design is based on the motor's performance requirements and the structural characteristics of the stator core. Winding design includes the number of turns, wire diameter, and winding method. The number of turns and wire diameter need to be calculated and selected based on parameters such as the motor's power, voltage, and current. Winding methods can include single-layer windings and double-layer windings. Single-layer windings are simple in structure and easy to manufacture, but their performance is relatively low; double-layer windings have higher performance, but their structure is more complex and more difficult to manufacture.
According to the design requirements, the wires are wound into a winding. Winding can be done manually or by machine. Manual winding offers high flexibility and is suitable for small-batch production, but is less efficient; machine winding is efficient and suitable for large-batch production, but is less flexible. During the winding process, it is necessary to carefully control the winding accuracy and quality to ensure that the number of turns, wire diameter, and winding direction of the winding meet the design requirements.
Install the wound windings into the slots of the stator core. During installation, pay attention to the winding arrangement and fixing method to ensure the stability and reliability of the windings. Methods such as binding and impregnation can be used to fix the windings. At the same time, pay attention to the insulation treatment of the windings to prevent short circuits between the windings and the core.
Electrical performance tests are performed on the stator core after the windings are installed, including resistance tests, insulation resistance tests, and withstand voltage tests. Resistance tests check if the winding resistance meets design requirements; insulation resistance tests check the insulation performance between the winding and the core; withstand voltage tests check the reliability of the winding's insulation performance under high voltage. Through these electrical performance tests, problems such as short circuits, open circuits, and poor insulation in the windings can be detected and repaired promptly.
The magnetic properties of the stator core are tested, including iron loss testing and magnetic flux density testing. Iron loss testing detects the energy loss of the core in an alternating magnetic field; magnetic flux density testing detects the magnetic flux density of the core in a magnetic field. These magnetic property tests allow for the evaluation of the core's magnetic permeability and losses, providing a basis for optimized motor design.
The mechanical properties of the stator core are tested, including hardness and strength tests. Hardness testing checks if the core's hardness meets requirements; strength testing measures the core's strength and deformation under stress. These mechanical property tests ensure the core possesses sufficient mechanical strength and stability during motor operation.
Choose appropriate packaging materials based on the size, weight, and shape of the stator core. Commonly used packaging materials include cardboard boxes, wooden crates, and plastic film. Cardboard boxes are low-cost and lightweight, but relatively weak; wooden crates are strong and offer good protection, but are more expensive; plastic film provides good moisture and dust protection, but has poor air permeability. When selecting packaging materials, factors such as cost, protective performance, and transportation requirements must be considered comprehensively.
Packaging the stator core ensures it is not damaged during transportation and storage. Packaging can be done individually or in batches. Individual packaging is suitable for small stator cores, facilitating transportation and management; batch packaging is suitable for large stator cores, improving packaging efficiency. During packaging, care must be taken to secure and protect the core, preventing it from shaking or colliding within the packaging.
The stator core should be stored in a dry, ventilated, and clean environment to prevent moisture, rust, and corrosion. The storage temperature should be controlled within a certain range, generally -20℃ to +40℃. Regular inspection and maintenance of the core are also necessary to ensure its quality and performance are not affected. During storage, contact between the core and other metal objects should be avoided to prevent electrochemical corrosion.