A disk media retaining and exchange system configured to accept a disk media assembly including a disk and a ferromagnetic material coupled therewith, includes a spindle motor assembly with a spindle motor and a permanent magnet retainer coupled therewith, whereby the system is configured to retain the disk on the spindle motor by a magnetic force between the ferromagnetic material of the disk media assembly and the permanent magnet retainer of the spindle motor assembly. An electromagnet disk exchange tool may be employed, configured such that energization of coils in close proximity to the disk media assembly overcomes the magnetic force to release the disk media assembly from retention with the spindle motor assembly, and generates another magnetic force between the ferromagnetic material of the disk media assembly and at least one electromagnet of the exchange tool to remove the disk away from the spindle motor for disk exchange.

A self-acting, sealed hydrodynamic bearing includes a bearing shaft; a bearing bushing arranged to seal a length of the bearing shaft; a lubricant provided in the sealed length of the hydrodynamic bearing; and a bearing arrangement between the shaft and bushing. The bearing shaft and/or the bearing bushing are configured to be rotatable. The bearing arrangement includes a primary bearing surface disposed on the bearing bushing, arranged to face a secondary bearing surface disposed on the bearing shaft. The primary and/or secondary bearing surfaces includes first regions having a first fluid slip characteristic, and second regions having a second fluid slip characteristic substantially different to that of the first fluid slip characteristic. The second and first regions are in a same plane of a cross-section of the primary and/or secondary bearing surfaces, and are disposed in an interleaved pattern over the primary and/or secondary bearing surfaces.

In certain embodiments, an apparatus includes a basedeck; a motor coupled to the basedeck and having a rotatable hub; and first, second, third, fourth, and fifth discs coupled to the hub. Three of the five discs are biased against the hub in a first direction and two of the five discs are biased against the hub in a second direction. In certain embodiments, a method includes biasing at least three discs against a hub in a first direction and biasing at least two discs against the hub in a second direction.

A rotating portion of a motor includes a magnet, a yoke, and a hub. An upper portion of the yoke is fixed to the hub. The yoke includes a first inner circumferential surface radially opposite to an outer circumferential surface of the magnet with a first gap intervening therebetween, and a second inner circumferential surface radially opposite to the outer circumferential surface of the magnet with a second gap intervening therebetween below the first inner circumferential surface. The second inner circumferential surface is parallel or substantially parallel to the outer circumferential surface of the magnet, and is located radially outward of the first inner circumferential surface. An adhesive is provided in at least a portion of the first gap. No adhesive is provided in at least a lower axial end portion of the second gap.

Hydrodynamic bearings exploit the properties of pumping action in a fluid to support a bearing load. Conventionally, the pumping action is provided by grooved surfaces in a bearing surface of the bearing. The provision of grooves leads to functional and practical problems, though. The action of grooves on a lubrication material leads inevitably to shear stress being exerted in the fluid. This has a detrimental effect on the load performance of a hydrodynamic bearing. In practical terms, the accurate manufacture of grooves is onerous. This application discusses a way of producing a hydrodynamic bearing using a portion of a bearing surface with an interleaved pattern of materials, wherein the materials have alternate high and low (or zero) fluid slip characteristics. The varying fluid slip characteristic of the surface induces a pumping effect analogous to that provided by a grooved surface.

In certain embodiments, an apparatus includes a basedeck; a motor coupled to the basedeck and having a rotatable hub; and first, second, third, fourth, and fifth discs coupled to the hub. Three of the five discs are biased against the hub in a first direction and two of the five discs are biased against the hub in a second direction. In certain embodiments, a method includes biasing at least three discs against a hub in a first direction and biasing at least two discs against the hub in a second direction.

A spindle motor having a turntable is disclosed, the spindle motor including a rotating rotation shaft, a turn table coupled to the rotation shaft to rotate along with the rotation shaft, and formed at a central upper surface with an accommodation groove, and a torque enhancement member coupled to the rotation shaft, and arranged inside the accommodation groove of the turn table to enhance a rotational torque of the turn table by depressing the turn table.

A magnetic disk device includes a plurality of disk-shaped magnetic disks 30, spacers 80, a hub 90, a clamp 70, and a fastening member 72. Each of the magnetic disks 30 includes a through-hole in a center section thereof. Each of the spacers 80 includes a through-hole in a center section thereof, and is disposed among the magnetic disks 30. The hub 90 is inserted into the through-holes of the magnetic disks 30 and the spacers 80. The clamp 70 presses and holds the magnetic disks 30 and the spacers 80. The fastening member 72 fastens the clamp 70 to the hub 90. The clamp 70 is fastened to the hub by the fastening member 72 with a torque of from 5 cN.Math.m to 45 cN.Math.m.