The effect of interference fit on vibration transmission from stator coil to base of a spindle motor in a hard disk drive

Abstract

The hard disk drive spindle motor is the primary source of vibrations that cause acoustic noise in the hard disk drive (HDD). The electromagnetic forces on the stator coil and the rotor, which are inherent to the operation of motors, are responsible for the deformation causing vibration of the motor’s interior structure. This vibration is transmitted to the motor exterior especially the motor base through the fit between the stator coil and the motor base. This article proposes an approach to reduce the acoustic noise of the HDD is hence by reducing the transmitted vibrational energy from the stator coil to the base by optimizing the interference fit between these two components. The effect of the fit on the transmitted vibrational energy through both the vibrational energy analysis through a friction model featuring micro-slip and the experimental investigations is studied. The vibrational energy analysis is applied on a hollow cylinder installed on a shaft as a simplified model of the stator coil and the base. The analysis shows that the transmitted torsional vibrational energy is proportional to the pressure due to the interference fit. Hence, it suggests that the reduction of the vibration transmission from the stator coil to the base can be done by decreasing the interference fit. In addition, the experimental investigations performed on three simple models of stator and base with different interference fits and also two groups of spindle motor samples with different fits agree well with the analysis.