Abstract: A spindle motor mounting structure for a disk or a disk cartridge recording/reproducing apparatus includes a substrate, a spindle motor including a stator part fixed on the substrate, a spindle shaft, and a disk shaped rotor part rotatably supported on the spindle shaft, and a frame on which the substrate is mounted. The rotor part has a flange part which extends from an outer periphery thereof, and the frame includes a projecting part which confronts at least a part of the flange to prevent the rotor part from slipping out of the spindle shaft. A height of an upper surface of the projecting part from the substrate is less than or equal to a height of an upper surface of the rotor part from the substrate.

Abstract: A pre-set variable passive element can prevent faulty insulation between itself and a conductive board. A cylindrical member extended higher than a adjusting member is made of ceramic around the adjusting member which is rotatably fitted for adjustment of the value of resistance of the pre-set variable resistor element, the forming of the cylindrical member being integrally formed with a main part also formed in a ceramic. The cylindrical member is fitted into an opening bored in a stator board mainly of a steel plate, and the pre-set variable resistor is fitted on the stator board. The adjusting member which is contacted by a contact, by which the value of resistance of the pre-set variable resistor element is determined, and an inside periphery of the opening free from any insulating treatment is securely insulated by the cylindrical member.

Abstract: A spindle motor able to reduce leaking of magnetic flux of an index magnet to a magnetic head of a disc apparatus. In an axial gap type spindle motor having a rotor case rotatably supported by a base plate, an index magnet is provided to a face of the rotor case opposite to the base plate. A hall device is provided in an open space between a plurality of coils arranged radially on the base plate at a position opposite to the index magnet. A magnetic flux forms a closed loop by passing through the rotor case, and thus leaking of magnetic flux to the outside is reduced.

Abstract: A stepping motor for driving a head carriage having a motor axis on which is provided a lead screw comprises a seat plate that forms a back end of the motor, said seat plate being provided with a projection that projects toward a radial direction of the motor axis. At the time of the alignment of a head and a disk, the stepping motor is rotated by rotating a jig which is engaged with the projection. Thus the stationary position of the head carriage along a direction of its movement is adjusted.