Study on Idle Noise Characteristics of Hard Disk Drives Based on a Multibody Dynamic Formulation

ABSTRACT With the increasing use of electromechanical systems, such as hard disk drives (HDD), CD-Rom drives, and DVD drives in the consumer electronics industry, there is a growing demand for quieter products. The noise emitted from these devices may originate from the vibration of mechanical components in operation, such as bearings, gears, and actuators, etc. The vibration is then transmitted to other parts of the devices, such as cover and basement, etc., and the noise emitted may then be amplified. This paper aims to present an approach to study idle noise, which is an important type of noise in HDD due to spinning. The dynamic characteristics of ball-bearing disks/spindle systems of HDD including flexible stationary structures, such as top cover, shaft, and basement, etc., are analyzed based on a multibody dynamic formulation. The discrete governing equations of motion for the system are derived through the use of Lagrangian equation while elastic deformations of the stationary structures are described by nodal coordinates from a finite element formulation. After obtaining the response of the stationary part, the subsequent radiated noise for different possible noise forces is calculated and analyzed based on finite element method. The characteristics of idle noise are identified. Finally some experiments about the noise are studied.