비대칭 착자에 따른 스핀들 모터 특성에 관한 연구

Abstract

ABSTRACT

A Study on Characteristic of Spindle Motor by Unsymmetric Magnetization Distribution in Permanent Magnet

by JAE YOUNG PARK under the supervision of Professor JU LEE, Ph. D. Department of Electrical Engineering The Graduate School of Hanyang University

In case, The permanent magnet of spindle motor for Optimal Disk Drive(ODD) is magnetized by magnetizer. Permanent magnet is generally putted between yoke and back yoke of magnetizer so that symmetric magnetization distribution. Magnetization Distribution of magnet is defined by magnetizer, and Chracteristic of Spindle motor is also defined by Magnetization Distribution of magnet. so, magnetizer is imfortant so that we abtain the magnet which we want. when Magnet is magnetized, yoke's position is center of magnetizer, and coil position is also centered in magnetizer for symertic magnetization distribution of magnet. However, In mass production of magnet of spindle motor for ODD the magnetizing yoke' eccentricity is occurred. and In mass production of magnetizer for spindle motor the magnetizing coil eccentricity is also occurred. So, for each case, magnetizing distribution of magnet is different from center position of magnetizing coil and yoke. when asymmetric distribution of magnet is mapped to spindle motor, Cogging torque and Back emf of spindle motor is different from symmetric distribution of magnet.[5] In this paper, according to previous paragraph, When magnetizing yoke eccentricity and magnetizing coil eccentricity is occurred, check out magnetizing distribution of magnet and when asymmetric distribution of magnet is mapped to spindle motor, To confirm change condition Cogging torque and Back emf of spindle motor conduct analysis using the finite element method(FEM). Reshape core of spindle motor to verify change condition Cogging torque when asymmetric distribution of magnet is mapped to spindle motor.