Abstract: A spindle motor comprising a bracket, a shaft member provided on the bracket, a rotor rotatably mounted to the shaft member through a pair of bearings, a rotor magnet mounted to the rotors, a stator disposed in opposite relation to the rotor magnet, and magnetic fluid sealing means respectively disposed outwardly of a pair of the bearings. The shaft member is provided with an air passage extending in the axial direction, and a communication passage for communicating the air passage with a space between a pair of the bearings. A cap member which is improved in its structure is disposed outwardly of one of the paired bearings. An annular projection for positioning the rotor magnet concentrically with respect to the rotor is provided on a magnet mount portion of the rotor.

Abstract: A spindle motor comprising a bracket, a shaft member secured to the bracket, a rotor rotatively supported by the shaft member while interposing bearings a rotor magnet fastened to the rotor and a stator disposed to confront the rotor magnet, wherein the rotor has a hub portion, to which a recording disk is fastened, and a rotor portion, to which the rotor magnet is fastened, the hub portion and the rotor portion being made to be interchangeable. The hub portion has a plurality of female screw holes for fastening the retaining cap, the number of a plurality of the female screw holes being different from the number of ball members of the ball bearing by at least two.

Abstract: A recording disk driving apparatus comprising a base plate, a cover member defining a disk chamber in cooperation with the base plate, a spindle motor disposed in the disk chamber, and a recording disk to be rotated and driven by the spindle motor. The base plate has a first convex portion projecting greatly inwardly and a second convex portion projecting greatly inwardly, and in correspondence to the first convex portion, a receiving concave portion for accommodating electronic components is provided in its back surface. Furthermore, a raising preventing member is provided to prevent the raising of the drawing portion of the flexible circuit board for supplying an electric current to the spindle motor.

Abstract: A spindle motor comprising a bracket, a shaft member provided on the bracket, a rotor rotatably mounted to the shaft member through a pair of bearings, a rotor magnet mounted to the rotor, a stator disposed in opposite relation to the rotor magnet, and magnetic fluid sealing means respectively disposed outwardly of a pair of the bearings. The shaft member is provided with an air passage extending in the axial direction, and a communication passage for communicating the air passage with a space between a pair of the bearings. A cap member which is improved in its structure is disposed outwardly of one of the paired bearings. An annular projection for positioning the rotor magnet concentrically with respect to the rotor is provided on a magnet mount portion of the rotor.

Abstract: A disk drive apparatus includes a magnetic disk, a spindle motor for rotating the magnetic disk, a magnetic head for writing data on and/or reading out data from the magnetic disk, a support arm for supporting the magnetic head, and a voice coil motor for pivoting the support arm. The spindle motor has a hub on which the magnetic disk is mounted, a rotor magnet mounted on the hub, and a stator disposed opposite to the rotor magnet. The stator includes a stator core around which an armature coil is wound. Teeth portions of the stator core are disposed substantially equiangularly in a circumferential direction while at least part of a plurality of coil winding portions are disposed non-uniformly in the circumferential direction, whereby the armature coils wound around the plurality of coil winding portions are retracted from a path in which the support arm is moved.

Abstract: A spindle motor includes a shaft, a hub assembly unit rotatable relative to the shaft, an upper bearing structure and a lower bearing structure both interposed between the shaft and the hub assembly unit, and a stator disposed between the upper and lower bearing structures. The stator, the hub assembly unit, and the upper and lower bearing structures are attached to a specific side of the shaft. The hub assembly unit has an aluminum-made hub and an iron-made yoke, both of which are joined together through a pair of fixing portions. One fixing portion has a relatively strong fitting force, whereas the other fixing portion has a relatively weak fitting force.

Abstract: A motor for rotating a magnetic disk, an optical disk, or a magneto-optical disk comprises an armature concentrically secured to a center shaft affixed to the base frame of a disk drive unit. A rotor frame is rotatably supported in a cantilever fashion on a free end of the center shaft by a pair of bearings. The rotor frame is cup-shaped with a depending cylindrical sidewall encircling the outer peripheral surface of the armature. The sidewall includes a disk support that projects outwardly from the sidewall. A permanent magnet secured inside the sidewall interacts with magnetic fields produced by the armature. The cantilever support makes it easier to bring armature leads through a hole in the mounting frame as a part of the manufacturing process.In an alternate embodiment, the center shaft is shortened so that the lower bearing on the shaft rests upon the frame. The cup-shaped rotor is mounted on the bearings with a hub having a depending cylindrical wall mounted on the lower bearing.