Reduced-height magnetic disk drive unit, and disk mounting device for the unit

A drive unit having a head for writing information on and/or reading information from an information carrier having a recording medium, comprising:

• (a) a drive means, arranged on a chassis of said drive unit, for providing a rotational force to rotate said information carrier, said drive means including a drive shaft and a rotor yoke having a top surface which receives said information carrier and having a bottom surface, said drive means additionally including a drive magnet which is arranged at an outer peripheral portion of said bottom surface of said rotor yoke to generate said rotational force of said drive means, said drive means having a stator yoke which is disposed in a concave portion of said chassis, said concave portion encompassing a thickness of said stator yoke by a depth of said concave portion;
• (b) an attracting magnet means for magnetically holding said information carrier, said attracting magnet means being mounted directly on said top surface of said rotor yoke;
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• (c) chucking means for transmitting rotation of said drive means to said information carrier, said chucking means being arranged at an inner portion defined between said drive magnet and said drive shaft and disposed in a plane defined by an upper surface of said drive magnet, said chucking means including a drive pin and a drive pin arm which is movably supported at the inner portion on the bottom surface of said rotor yoke and which mounts said drive pin for movement with respect to said top and bottom surfaces of said rotor yoke, said drive pin being engageable with said information carrier received on said top surface of said rotor yoke.

A magnetic disk drive unit having a magnetic head for writing information on and/or reading information from a disk having a magnetic recording medium, comprising:

• (a) a disk mounting device which includes (i) a disk drive motor means for rotating said disk, said disk drive motor means having a drive shaft and being in the form of a direct drive spindle motor which includes a rotor portion and a stator portion, said rotor portion having a rotor yoke and a drive magnet and said stator portion having an electromagnetic coil and a stator yoke, said rotor yoke having a top surface which receives said disk and having a bottom surface, said drive magnet being arranged at an outer peripheral portion of said bottom surface of said rotor yoke;
• and (ii) an attracting magnet means for magnetically holding said disk, said attracting magnet means being mounted directly on said top surface of said rotor yoke;
• (b) a chassis on which said disk mounting device is fixedly mounted, said chassis having a wall which lies in a plane, part of said wall being removed to provide a concave portion in which said stator yoke of said stator portion is disposed, said concave portion encompassing a thickness of said stator yoke by a depth of said concave portion, said magnetic head being disposed at a distance from said plane that is approximately the same as the distance between said rotor portion and said plane, said magnetic head additionally being disposed so that a line perpendicular to said plane and passing through said magnetic head does not also pass through said rotor yoke;
• and
• (c) chucking means for transmitting rotation of said disk drive motor means to said disk, said chucking means being arranged at an inner portion defined between said drive magnet and said drive shaft and disposed in a plane defined by an upper surface of said drive magnet, said chucking means including a drive pin and a drive pin arm which is movably supported at the inner portion on the bottom surface of said rotor yoke and which mounts said drive pin for movement with respect to said top and bottom surfaces of said rotor yoke, said drive pin being engageable with said disk received on said top surface of said rotor yoke.