It is known that the quasi-rigid body mode (QR mode) vibration is one of the main sources for generating the residual vibration in settling operation and limiting the servo bandwidth, and is mainly caused by the stiffness of the pivot, the mass, and structure of the head actuator arm. The ball bearings inside the pivot determine the pivot stiffness, which in turn, determine the effective stiffness of the head actuator assembly. In this paper, the stiffness-related issues among ball bearings, pivot, and head actuator assembly are studied theoretically and experimentally. It shows that the pivot effective radial stiffness depends not only on the stiffness of the ball bearing, but also on the connection method used to attach the pivot to the head actuator arm. It is also shown from the measurement and analysis that the resonance frequency of the QR mode, determined by the pivot effective radial stiffness and inherent properties of the head actuator arm, can be moved to a higher frequency by using a more rigid pivot and a more stiff joint.
|Number of pages||9|
|Journal||Journal of Information Storage and Processing Systems|
|Publication status||Published - Jul 2001|
- Ball bearing
- Head actuator assembly
- Quasi-rigid body