수동형 자기 베어링과 유체 동압 저널베어링을 이용한 HDD용 스핀들 모터 개발

Development of a HDD Spindle Motor Using Passive Magnet Bearing and Fluid Dynamic Journal Bearing

This paper presents a highly efficient HDD (Hard Disk Drive) spindle motor with a passive magnetic thrust bearing and a fluid dynamic journal bearing and its effectiveness is verified through experiment. It eliminates the mechanical friction loss of a thrust bearing which is around 18% of total power consumption of a 3.5' HDD spindle motor, by replacing a conventional fluid dynamic thrust bearing with a passive magnetic thrust bearing. The passive magnetic thrust bearing using permanent magnets is inherently unstable in radial direction. However, the radial fluid dynamic force of the fluid dynamic journal bearing counterbalances the radial magnetic force of magnetic thrust bearing to achieve the stability as the motor spins up. It has less or equivalent runout and less flying height than the conventional spindle motor.