Patent ID: 7256959

Claim:
A magnetic disk device comprising a magnetic disk, a motor ( 4 ) for rotating the magnetic disk through its rotating shaft ( 12 ), a head for writing data to the magnetic disk or reading out data from the magnetic disk, an arm on which the head is supported, an actuator ( 3 ) connected to the arm to move the head generally in a radial direction across the magnetic disk, a base ( 1 ) on which the magnetic disk, the motor ( 4 ) and the actuator ( 3 ) are supported and accommodated, and a cover ( 40 ) for enclosing the entire device in association with the base ( 1 ), said cover comprising a dome comprising concentric steps, the center of the dome being concentric with rotating shaft ( 12 ), wherein the cover ( 40 ) is placed opposite to the magnetic disk and is formed so that the gap between the inner surface of the cover ( 40 ) and the magnetic disk is reduced along a direction from the rotating shaft portion of the motor ( 4 ) toward the outer periphery of the magnetic disk.