Theoretical Analyses and Experiments of Micromachined Graphite Rotor Based on Diamagnetic Levitation

Abstract

Abstract: A diamagnetic levitation structure consisted of NdFeB permanent magnets and a highly oriented pyrolytic graphite rotor was studied herein. The rotor was designed as a disc with four identical blades. The gravity of the rotor was equal to the diamagnetic force from the permanent magnets, leading to the stable levitation and consistent rotation of the rotor under external driving torques. The levitation height of the rotor was simulated to be 130μm in the finite element analysis software, which matched well with the experimental results, and the simulation errors are as 1.5%. In order to introduce a driving torque, needle nozzle was adopted to produce tangential airflow to the blade of the rotor. The relationship between the rotor rotation speed and the flow rate of the airflow was investigated and analyzed, and the maximum speed of the rotor could reach 500r/min. The diamagnetic structures possess potentials in the applications of non-contact microsensors and micromotors.

Key words: graphite rotor, diamagnetic levitation structure, external driving torque, rotation speed measurement

摘要：

提出了一种由钕铁硼永磁体和高定向热解石墨转子组成的抗磁悬浮结构。石墨转子采用四个叶片结构，其重力与永磁体对它的抗磁力相等，从而实现转子稳定地悬浮在永磁体上方，并在外界驱动转矩的作用下发生转动。有限元软件中仿真得到石墨转子的悬浮高度为130μm，与实验测量值吻合较好，仿真误差为1.5%。实验中利用针孔喷嘴向转子叶片处施加切向气流作为驱动转矩，对转子的旋转速度与气流流速的相对关系进行了测试分析，发现转子最大转速可达500r/min。该抗磁悬浮结构有望用于非接触式的微型传感器和微型电机中。

关键词: 石墨转子, 抗磁悬浮结构, 外界驱动转矩, 转速测量

CLC Number:

TH16
TH703

SU YufengYE ZhitongZHANG Kun. Theoretical Analyses and Experiments of Micromachined Graphite Rotor Based on Diamagnetic Levitation[J]. China Mechanical Engineering.

苏宇锋, 叶志通, 张坤. 抗磁悬浮石墨转子理论分析与实验[J]. 中国机械工程.

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