in recent years, the domestic multi-polar magnet technology, a new breakthrough can already replace the magnetic tile because it simplifies the motor structure, but also optimize the motor performance. this multi-pole magnet can be used to produce micro-motor (a few watts to hundreds of watts) of the rotor or stator, is widely used.
with the magnetization technology, multi-polar magnet product quality continues to increase. a multi-polar magnet magnetizing method generally have the following:
(1) the mosaic law generally will be aluminum nickel and cobalt metal magnetic nsn ... ... uniformly embedded in a non-magnetic cylinder, making a multi-polar magnet. this approach complex process, high cost, small size problems.
(2) the patchwork method to multi-block magnets evenly by sns ... ... ring directly bonded to a multi-polar magnet. similar shortcomings with the mosaic method.
(3) solenoid france this is a good and effective magnetizing method, is still a large number of uses. the disadvantage is that miniaturization difficult. diameter is small, a very few number of magnetic ring, such as the outside diameter φ14mm or φ16mm, to charge 24 very even impossible.
engineering, coil for generally use 5 to 30 turns, guided magnets generally used in industrial pure iron, the coil current generally tens to hundreds of amperes, the magnetic circuit length is generally a few centimeters or tens of centimeters. specific parameters, should be based on magnetizing device, is magnetizing product dimensions and the number of poles reasonable choice in order to achieve the desired effect.
(4) the magnetic field lines bombardment which is an advanced magnetizing method is suitable for small diameter, very few number of internal and external magnetic ring magnetic charge. for example φ14mm or φ16mm magnetic ring, filling 24-pole magnetic ring can also be 2,4,6,8,10 most other domestic and foreign magnetization, as well as more than 24 highly magnetized. using this method φ135mm (outer) × φ118mm (within) × 35mm (height) of the magnetic ring, performance very good to meet a few hundred watts dc synchronous motor needs.
are presented this magnetizing method of characteristics:
isotropic ferrite for permanent magnet is 0.09 ~ 0.16t; magnetic surface utilization of 95% ~ 98%, is conducive to a smooth uniform operation of the motor; able to meet a few watts ~ a few hundred watts dc motor needs.
using magnetic field lines of a company bombardment way of producing ferrite permanent magnet material properties such as shown in table 1.
table 1 ferrite magnet materials
magnet od / mm
magnet poles
the surface magnetic flux density / t
φ14
24
0.08 ± 0.01
φ16
24
0.09 ± 0.01
φ19
24
0.09 ± 0.01
φ22
24
0.09 ± 0.01
φ26
24
0.11 ± 0.01
φ28
24
0.11 ± 0.01
┆
┆
┆
φ135
24
0.11 ± 0.16
these are the use of ferrite materials, production of the same sex, and its energy product (bh) max = 8 ~ 9.6t · a / m. if the use of anisotropic materials, performance can be increased by 5% to 15%; use of rare earth materials, magnetic properties will be better.