Nils E. Larson

Acoustic noise reduction system for a disk drive

A noise suppression system for use in a disk drive. The system isolates the interface between the disk drive cover and the moving parts of the disk drive to attenuate acoustic energy introduced by the moving parts and also dissipates some of the unwanted acoustic energy in viscoelastic damping layers. An outer plate made of a rigid layer covered with a viscoelastic damping layer is disposed over an inner cover in which is provided an open region surrounding the pivot axis of the head-stack assembly (HSA) or, alternatively, surrounding both the pivot axis and the spindle axis of the disk assembly. A rigid interface member is fixed to the pivot journal or, alternatively, to both the pivot journal and the spindle journal within the open region. The outer plate is fitted to the periphery of the inner cover so that the viscoelastic damping layer abuts a flexible sealing member fitted over the interface member and inner cover around the open region. The sealing member includes a soft metal substrate for sealing the head-disk assembly (HDA) chamber of the disk drive. The viscoelastic damping and adhesive layers are constrained between the outer plate and the sealing member to isolate the interface member from the outer plate within the open region of the inner cover. Any acoustic energy introduced into the interface member is at least partially dissipated by shear wave losses within the constrained viscoelastic layer.