Design and analysis of auto-balancer of an optical disk drive using speed-dependent vibration absorbers

With the increased demands in performance, the optical disk drive needs to be high speed and more stable. A novel design of a vibration absorber used in reducing the vibration caused by the imbalance of an optical disk drive is proposed. When an optical disk is rotating, the vibration caused by the imbalance resulting from the non-homogeneous disk increases as the rotating speed increases. The proposed vibration absorber with a circular shape is installed beneath the optical disk. It rotates with the disk; therefore its natural frequency varies with the rotating speed due to the change of in-plane stress caused by the centrifugal force. The objective is to use shape optimization technique to make the first radial natural frequency of the absorber coincide with the rotating speed of the optical disk in a specific frequency range. Under this circumstance, the natural frequency of the absorber becomes speed-dependent and the absorber will keep resonant in this specific frequency range. It can effectively suppress the vibration in the radial direction caused by the imbalance of the optical disk and acts as an auto-balancer. Results from experiments and numerical simulations using finite element method both show that the imbalance of the optical disk can be reduced effectively.