Abstract: A low airflow hard disk apparatus comprises a base, a cover member, a rotational portion disposed in a disk chamber, a hard disk held by and rotatable with the rotational portion, a first projection portion disposed on the lower surface of the cover member and facing toward the upper surface of the hard disk, and a second projection portion disposed on the upper surface of the base and facing toward the lower surface of the hard disk. The first and second projection portions, preferably radially extending fins, prevent an air flow from generating by the rotation of the hard disk.

Abstract: A spindle motor comprises a stationary member, a hub which is mounted rotatably on the stationary member through a pair of bearings, a rotor magnet which is mounted on the hub, a stator located face to face to said rotor magnet and a clamp for mounting recording disks to the hub. The hub is provided with a mating protrusion for fixing the clamp, the mating protrusion is fitted with a flat end of the hub, and the clamp is fixed by mounting the flat end of the hub with a fastening screw. Further, with a sealing member being fitted on the bearing, a labyrinthine sealing structure is formed with the sealing member and the stationary member.

Abstract: An annular recess is formed in a base which constitutes a disk chamber, and an armature constituting a spindle motor for driving a hard disk and composed of a stator core and a stator coil and a field device composed of a rotor yoke and a rotor magnet are substantially accommodated in the annular recess. As a result, the height of a portion of a hard disk apparatus which constitutes a radial directional gap type spindle motor can be minimized and therefore the overall height of the apparatus can be minimized. Hence, the thickness and the size of a computer apparatus or the like which includes the hard disk apparatus can be reduced.

Abstract: A spindle motor comprising a bracket, a hub which is rotational relative to the bracket, and bearing means disposed between the bracket and the hub, wherein the hub has a hub main body made of aluminum or an aluminum alloy, and a holder formed from a magnetic material, and wherein a rotor magnet is mounted on the inner surface of the holder. A ring-shaped recess is provided on the inner surface of the bracket, and the hub and a part of the rotor magnet extend into the ring-shaped recess. Improvements having been made on a disk clamp mechanism for mounting a recording disk on the hub of the spindle motor.

Abstract: A spindle motor includes a bracket, a shaft member fixed to the bracket, a hub member rotatably mounted on the shaft member with a bearing member therebetween, a rotor magnet mounted on the hub member, a stator disposed in opposed relation to the rotor magnet, and a magnetic fluid sealing assembly disposed on on outer side of the bearings. The shaft member has an elastic sealing member which seals a through-hole formed in the shaft.

Abstract: A spindle motor includes a bracket, a shaft member fixed to the bracket, a hub member rotatably mounted on the shaft member with a bearing member therebetween, a rotor magnet mounted on the hub member, a stator disposed in opposed relation to the rotor magnet, and a magnetic fluid sealing means disposed on an outer side of the bearing means. The shaft member or bracket has a magnetized portion for suppressing a magnetic flux leaking from a magnetic fluid retaining means of the magnetic fluid sealing means.

Abstract: A magnetic fluid seal assembly comprising an annular sealing clearance communicating with an external space, an annular permanent magnet for forming a magnetic field in the sealing clearance, a ferromagnetic fluid retained in the sealing clearance by the magnetic field but rotationally movable in the sealing clearance, and a scattering preventive portion provided axially outwardly of the sealing clearance for preventing the ferromagnetic fluid from scattering to the external space when the ferromagnetic fluid is rotationally moved.