NdFeB磁粉用于提高磁性编码器的分辨率可行性探讨

Discussion of NdFeB for Improving Distinguish-ability of Magnetic Rotary Encoder

在研究直径为32mm产生800个磁极的磁鼓时发现,高分辨率的磁性编码器离不开高性能的磁性材料。实验研究中,将NdFeB、AlNiCo、铁氧体等三种材料分别采用不同粉末粒度与不同配比的粘接剂进行搅拌,使之充分混合均匀。然后,采用加温压铸方法使混合物致密,并固化成型,再进行无损检测,以便比较磁记录信号写入的效果。通过单个码写入和多个码一次性写入方法进行磁信号录入实验,经用磁头和GMR传感器制成的装置检测发现,媒质性能不同对信号波形幅值大小有较大影响。致密度的高低或混合不均匀会引起波形畸变,导致输出信号重复性差,不利于采用细分技术提高磁编码器的分辨率。本文对NdFeB、AlNiCo、铁氧体等三种材料分别做了对比试验,选出了性能最佳的材料,解决了致密度对信号波形重复性差的问题。这些结果对生产高性能、高分辨率的旋转磁性编码器有重要的价值。

It is found that rotary magnetic encoding of high-distinguished ability has a relation to magnetic materials when studying the magnetic drum of 800 bits in diameter 32 mm. In the experiment, NdFeB, AlNiCo and Fe_2O_3 have been used.Each time one powder of NdFeB, AlNiCo and Fe_2O_3 is mixed with adhesive of different ratios, after making mixture well. Then make them compact by heat die-casting, and move it out of the model. The sample is examined with no damage in order to compare results that magnetic signals are recoded in. The experiment has been done with the magnetic code recoding one by one or at one time. The magnetic signals were detected with the sensor of magnetic head and GMR. The results showed that the media of different property affected greatly the waveform of the signal. If density of compaction is not even or the mixture is not mixed evenly, it will lead to distortion of the signals waveform or bad repeatability of the output signals. It is not benefit to improve distinguish-ability by subdivision-phase technology. In this paper, the authors respectively have contrasted experiments with NdFeB, AlNiCo and Fe_2O_3, and have selected the best one, resolving the problem of uneven density leading to bad repeatability of the signal waveform. The obtained results are of good value for making a magnetic rotary encoder of high distinguish ability.