Disk driver having a dust proof rear cover fitted on a rear wall of a frame unit

A disk drive comprising:

• a frame unit having a rear wall formed integrally with a bottom plate made by press work from a plate, said rear wall having at least one opening portion comprising a hole or gap space, and a fixing member rearwardly extending from an edge of said opening portion for fixing a circuit board thereto, said rear wall having a rear cover mounted thereon for closing said opening portion to the environment;
• a disk holder unit for receiving a disk, said disk holder unit being in said frame unit and driving said disk;
• a carriage assembly including a recording and reproducing head for recording information on and reproducing information from said disk, said carriage being mounted at said rear wall of said frame unit;
• and
• a stepping motor mounted on said rear wall for driving said carriage assembly forward and backward;
• said circuit board extending from a position beneath said bottom plate and rearwardly beyond said rear wall, and said circuit board including a circuit for driving said recording and reproducing head and said stepping motor, and an electrical connector for connecting said circuit with external devices;
• said rear wall including a wall engaging member, said wall engaging member comprising a notch or a hole;
• and
• said rear cover including a cover engaging member for engaging with said wall engaging member when said cover is mounted on said rear wall;
• whereby shifting of said rear cover in a direction along a surface of said rear wall is prevented and entry of dust into the equipment is prevented.