Patent ID: 7330334

Claim:
A magnetic disk apparatus comprising: a plurality of magnetic disks driven to rotate by a spindle motor; arms supporting magnetic heads on said magnetic disks; an actuator for moving said arms on said magnetic disks by a voice coil motor; and a housing surrounding said magnetic disks, said arms and said actuator; wherein a shroud which arcuately surrounds said magnetic disks along the outer periphery thereof and has an opened portion for inserting said arms is formed in a part of said housing; wherein said shroud on an upstream side of said arms relative to airflow generated by said magnetic disks when rotating is provided with an opening having a greater width than that of a gap defined between said shroud and said outer periphery of said magnetic disks; wherein an empty bypass channel is provided and which communicates from said opening through a rear side of said voice coil motor to the downstream side of said arms; wherein an open space sufficient to permit all of said arms to move from over said magnetic disks beyond said outer periphery of said magnetic disks is provided on the downstream side of said arms, and said empty bypass channel communicates with said open space; and wherein an air passage is formed, which has an air inlet and an air exhaust port opening on said shroud, said air passage being provided with a filter.