A new air circulation path for a high-recording-density magnetic hard-disk drive

A novel air circulation path for a closed-type magnetic hard-disk drive, in which a partition divides the drive into a disk room and an actuator room, has been developed. The air flows out from the disk room through exit windows in the partition, flows through an actuator coil and a filter, and then flows back into the disk room. Visualization of the flow in a 3-in model disk drive without the partition reveals axial mixing flow in the outer spaces of the disks, a jet along an obstacle adjacent to the outer edges of the disks and a whirl induced by the jet, and a reverse flow in the wake of the obstacle. Flows of this nature cause reverse flows at exist windows of a partition for an 8.8-in drive. The addition of flow balancers, suitably designed height and position of the exit windows, and guides in the wakes of head arms reduce the reverse flows. The air circulation capability of the disk room, the operating conditions of the drive, and relations between the operating conditions and the reverse flow are discussed in relation to the circulation-flow-rate and the discharge-pressure characteristics