Design of Herringbone Groove Disk Damper for Effective Suppression of Axial Vibration of Disk in Hard Disk Drive

Abstract

A herringbone groove pattern is applied to a plane disk damper of a hard disk drive to reduce the axial vibration of the disk rotating at high speed. According to the design parameters such as mean radius r <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> , ridge-groove ratio B, and spiral angle β , the performance of the herringbone groove disk damper is studied numerically in terms of the stiffness and the damping coefficients and the ratio of the axial stiffness to the frictional torque. The dynamic coefficients are calculated from the result of computational fluid dynamics solution of a simple hard disk drive model using four-point central difference scheme. To confirm the numerical results, the nonrepeatable run-out of the disk is measured when a plane or a herringbone groove disk damper is used. It is found that a herringbone groove disk damper increases the stiffness as well as the damping coefficient of the air film by 20% more than those of a plane disk damper.