First, the definition of magnetic tile: magnetic tile talking about here is a permanent magnet in a permanent magnet motor is mainly used in the tile-shaped magnets.
Second, the magnetic tile classification: magnetic tile depending on their raw materials are mainly three categories:
1, ferrite magnetic tile
2, NdFeB magnetic tile
3, alnico magnet
Third, the magnetic tile uses:
Magnetic tile mainly used in permanent magnet DC motor with electromagnetic motor generates different magnetic potential source through the excitation coil, a permanent magnet motor is a permanent magnet material to produce a constant magnetic potential sources. Tile instead of permanent magnet electric field has many advantages, can make simple motor structure, easy maintenance, light weight, small size, reliable, use less copper, low copper consumption, energy consumption and small.
Effect of magnetic-watt motor Performance
(1) a high residual magnetic flux density Br. Because Br high to ensure that the motor has a high speed, high torque and high output power. The motor will have a higher efficiency.
(2) high Hcb. Because Hcb high to ensure the required motor output electromotive force, the motor operating point close to the maximum energy product, make full use of the capacity of the magnet.
(3) High Hcj. Hcj high can ensure that the motor has a strong resistance to overload demagnetization and aging, resistance to low temperature.
(4) high (BH) max. (BH) max higher scores indicating better permanent ferrite motor duty factor in the actual operation.
(5) The magnetic energy Φ bigger the better, which will greatly improve the efficiency of the motor.
Squareness (6) of the demagnetization curve, the better, the smaller the dynamic losses of the motor.
(7) Ferrite The higher the resistivity, the smaller the eddy current losses.
(8) Ferrite temperature coefficient is small, at high temperatures it has good temperature stability
Fourth, the development history
Development is based on a permanent magnet magnetic tile motor itself needs change.
1) permanent magnet motors are permanent magnet DC motor with permanent magnet AC motor.
1.1 permanent magnet AC motors refers multiphase synchronous motor with a permanent magnet rotor, previously mainly nickel and cobalt ferrite magnetic tile with aluminum, with power increasingly demanding, aluminum, nickel and cobalt ferrite and because BH Low does not meet the requirements, now NdFeB magnetic tile in the field of high-power synchronous motors and generators very wide application. Of course NdFeB magnetic tile, precious because rare earth resources, raw materials prices rise exponentially, its manufacturing costs and production prices will continue to increase, affecting its extensive use in some low areas. NdFeB itself a negative temperature coefficient, low Curie temperature, but also limits its high temperature applications should be transported.
1.2 permanent magnet brushless DC motor and is divided into ordinary DC motor with commutator, from the shape, the number of poles of the magnet to determine its application
In general DC motor, with 2 and 4-pole majority, and the magnetic tile basically used for the stator, the majority of miniature DC motor using ferrite magnetic tile, mainly used in toys, appliances, automotive sector. Brushless motor magnetic tile as a stator, generally more than 6-pole, so the central angle is much smaller than the magnetic tile with ordinary DC motor. But as the brushless motor magnetic tile rotor poles may have 4,6 or more, for 4-pole, the outer surface of the rotor is magnetized, and makes up a round due to its central angle approaching 90 °, this as can be distinguished from ordinary DC motors.
2), the magnetic tile according to different application areas, as well as the performance of the magnetic field waveform requirements are also different, as the rotor field, outer arc table field requirements, the basic requirements for the sine waveform, as a stator, then according to the requirements of the motor output, spark as well as the different requirements of the noise are selected as the stator magnetic tile, its inner arc table games is high, due to the shape of the magnetic tile production characteristics of the decision itself, which is mainly saddle-shaped waveform, such large output waveform, but the spark noise, idling Current large. To improve noise and vibration, commutation spark, reduce load current, the magnet shape and size, mold design, etc. should be carefully designed, ranging from thick magnetic tile, etc. which have been widely used, the principle is the inner magnetic tile arc gap field waveform tends topped waves.
3, a special purpose: to make the ferrite tile earliest enterprises such as Sichuan 899 (Yi Bin Jinchuan Electronics Co., Ltd.), Meizhou City, Guangdong Province, magnetic materials factory, magnetic cup in popularity during the eighties and nineties, have used magnetic tile as the magnetic field source magnetized Cup. At that time, the demand for ferrite magnetic tile are few.
Fifth, the production process. Magnetic tile according to different categories of material, the process also vary greatly.
Ferrite tile-based sintered ferrite, NdFeB sintered and bonded magnetic tile is divided into two categories.
1, the sintered ferrite magnetic tile production process is divided into whether there are heterosexual orientation of the magnetic field wet pressing, dry pressing homosexual, heterosexual dry-pressed, its heterosexual and homosexual difference is that the press molding. This introduces the wet-wet pressing technology heterosexual Process: raw material - calcined - coarse crushing (primary milling) - Ingredients - secondary ball milling (wet milling) - magnetic field molding - sintering - Grinding - Cleaning - magnetization. Because forming slurry contains water, forming particles in a magnetic field so easily turned Bigan pressure heterosexual can achieve higher degree of orientation, its performance will be higher.
2, sintered NdFeB magnetic tile: Ingredients - Melting - Crushing - Milling - magnetic molding - HIP - vacuum sintering and tempering - cutting and other machining - Electroplating - magnetizing.