Vibration of hard disk drive spindle systems with distributed journal bearing forces

Abstract

This paper is to analyze vibration of fluid dynamic bearing spindles with distributed journal bearing forces. The dynamical model is developed to predict the transverse vibration of the disk-spindle systems in HDD where an aspect ratio of the bearing width to the shaft length is significant and the shaft is likely flexible. In such spindles the journal bearing functions as a continuous support, providing the distributed restoring and damping forces, and is therefore modeled as distributed linear spring and damping forces through distribution functions of dynamic coefficients. Vibration analysis reveals that the spindle model with distributed bearing forces predicts the same natural frequencies for all transverse modes but higher modal damping of the rocking modes, when compared to the values predicted by the conventional model with discrete bearing forces. The difference in damping prediction is clearer for the flexible-shaft spindle whose ratio of the bearing width to the shaft length becomes larger.

Experimental Stability Study on Herringbone-Microgrooved Journal Bearing in an Impeller-Spindle

“…Few researchers have experimentally investigated the dynamic characteristics of HDD systems with the herringbone-microgrooved journal bearing. Jintanawan [10] presented a dynamic model of a disk-spindle system with distributed forces in herringbonemicrogrooved journal bearing for predicting the transverse vibrations of HDD spindles. Miwa et al [11] proposed a new method for evaluating the damping and frequency characteristics of fluid dynamic bearing (FDB) spindle, using a high-frequency vibration base.…”

Hard Disk Drive Mechanism Vibration Damping Using Disturbance Observer

“…The improvement of vibration control has been discussed from various aspects and solutions proposed such as by applying several control algorithms, developing new design of actuator, embedding secondary actuator to the system and others [2] It has been shown by Jintanawan that the vibration increases with higher HDD rotational speed [6]. Wood suggested that the HDD must be stiff enough to suppress the vibration [7].…”