The concept of Haier Beck array
This array is entirely composed of rare earth permanent magnet materials. By arranging permanent magnets with different magnetization directions according to a certain rule, magnetic field lines can converge on one side of the magnet and weaken on the other side, thus obtaining a relatively ideal unilateral magnetic field. This is of great significance in engineering, as the Haier Buick array is widely used in industrial fields such as nuclear magnetic resonance, magnetic levitation, and permanent magnet special motors due to its excellent magnetic field distribution characteristics.
On the left is a single magnet, with all the north poles facing upwards. The color indicates that the strength of the magnetic field is located at the bottom and top of the magnet. On the right is a Halbeck array, where the magnetic field at the top of the magnet is relatively high, while at the bottom it is relatively weak. The strong side surface magnetic field strength of the Haier Beck array magnet group under the same volume is about √ 2 times (i.e. 1.4 times) that of a traditional single magnet, especially when the thickness of the magnet magnetization direction is 4-16mm. The most common example of Haier Beck array may be the flexible refrigerator sticker. These thin and soft magnets are usually printed and pasted on refrigerators or the back of cars. Although their magnetism is relatively weak compared to neodymium iron boron (only 2% -3% strength), their low price and practicality make them widely used.
linear array
Linear Halbach array is the most basic form of Halbach array composition, and this array magnet can be regarded as a combination of radial and tangential arrays. Linear Halbach array is currently mainly used in linear motors. The suspension principle of maglev trains is the interaction between the moving magnet and the magnetic field generated by the induced current in the conductor, which generates a suspension force accompanied by magnetic resistance. Improving the ratio of buoyancy to resistance is the key to improving the performance of the suspension system, which requires the onboard magnet to be lightweight, strong in magnetic field, uniform in magnetic field, and highly reliable. The Halbach array is horizontally installed in the center of the vehicle body, which interacts with the winding in the center of the track to generate propulsion force, achieving maximum magnetic field with less magnet usage, while the other side has less magnetic field, allowing passengers to avoid exposure to strong magnetic fields.
Polar Array
The circular Halbach array can be regarded as a combination of straight Halbach arrays connected end-to-end to form a circular ring shape.
In permanent magnet motors, permanent magnet motors using Halbach array structures have air gap magnetic fields that are closer to a sine distribution than traditional permanent magnet motors. With the same amount of permanent magnet material used, Halbach permanent magnet motors have a higher air gap magnetic density and lower iron loss. In addition, Halbach ring arrays are widely used in permanent magnet bearings, magnetic refrigeration equipment, and magnetic resonance equipment. The production and manufacturing method of Haier Beck array
Method 1: Based on the topology of the array, use magnetic adhesive to bond the pre magnetized magnet segments together. Due to the strong mutual repulsion between each magnet segment, a mold should be used for clamping during bonding. This method has lower manufacturing efficiency, but is easier to implement and is more suitable for use in laboratory research stages.
Method 2: Firstly, a complete magnet is manufactured using the filling or pressing method, and then magnetized in a specially designed fixture. The array structure processed using this method is similar to the one shown in the figure below. This method has high processing efficiency and is relatively easy to achieve mass production. But it requires specialized design of magnetizing fixtures and development of magnetizing processes.