Magnetic recording and reproducing apparatus having disk centering bearing

Claim 1

In a magnetic recording and reproducing apparatus including a turntable supported rotatably by ball-type bearings on a fixed shaft, including an upper bearing having an inner ring fixed on the shaft, a rotatable outer ring, and balls between the two rings, said turntable being adapted to support a magnetic disk on an upper surface thereof, the magneetic disk having a central hole of a standard inner diameter by which it is centered on the turntable, wherein the improvement comprises said upper bearing being dimensioned such that an outer peripheral surface of its outer ring has an outer diameter which substantially fits directly in the standard inner diameter of the central hole of the disk, and at least a portion of said upper bearing projects above the upper surface of the turntable such that a magnetic disk having the standard inner diameter hole becomes centered on the turntable directly by the outer peripheral surface of the outer ring of said projecting upper bearing without the need for an intervening driving member.