A disk clamp for a hard disk drive, configured to clamp disk media to a spindle, includes multiple protrusions extending from a surface of a bottom side and configured to contact a disk medium at multiple contact positions in response to application of a clamping load. The protrusions may be annular protrusions circumscribing a disk clamp hub, where the height of an inner protrusion may be less than the height of an outer protrusion to inhibit coning of the top disk medium, and the protrusions may be positioned so that an equivalent contact radius corresponding to contact radii of the inner and outer annular protrusions is at a position halfway between the inner and outer diameters of the disk spacers to inhibit coning of the middle disk media.

A method includes coupling an electric motor in a hard disk drive to a set of driver circuits. Each driver circuit includes a high-side switch and a low-side switch. The high-side switch has a high-side current flow path between a supply node coupled to a supply voltage and a switching node coupled to a winding of the electric motor. The low-side switch has a low-side current flow path between the switching node and ground. Respective conduction currents are generated through the low-side current flow paths, in response to a command to reduce the motor speed by coupling a drive voltage to the control terminals of the low-side switches. An intensity of at least one of the respective conduction currents is sensed. In response to the sensed current intensity exceeding a current intensity threshold, the control terminals of the low-side switches are coupled to respective ones of the switching nodes.

According to one embodiment, a disk device includes a housing with a bottom wall, magnetic disks supported on a hub of a motor, a printed circuit board provided on an outer surface of the bottom wall, and a wiring board attached on the outer surface of the bottom wall. The bottom wall includes a recess formed in the outer surface, a step located on border between the outer surface and the recess, and through holes opened to the recess. The wiring board includes one end portion disposed in the recess and connection pads on the one end portion, connected to lead wires of a coil. An adhesive is filled into the recess and the through holes, and covers the one end and a solder joint and seals the through holes.

A removable disk clamp assembly for mounting disk media on a motor-driven spindle of a magnetic read-write device includes a disk clamp and a mechanism for generating a predetermined force to press the disk media to a flange of the spindle such that the predetermined force can be repeatedly overcome by an applied counterforce to remove the disk clamp from engagement with a hub of the spindle. Such a mechanism may include a spring-loaded removable disk clamp assembly or a magnetic removable disk clamp assembly, and whereby a vacuum-driven chuck may be employed for disk and clamp handling purposes, all of which are suitable for implementation and use in a read-write device configured for use in an archival data storage system library such as in a cleanroom storage system.

A motor includes a shaft, a base portion, a stator, and a rotor. The shaft extends along a central axis extending in an axial direction. The base portion extends in a radial direction on one axial direction side of the shaft. The stator is located in another axial direction with respect to the base portion and surrounds the shaft. The rotor is rotatable around the central axis. The rotor includes a rotor tube portion, a magnet, and a rotor flange portion. The rotor tube portion surrounds the stator. The magnet is opposed to the stator in the radial direction. The rotor flange portion extends in a radially outer direction from one axial end portion of the rotor tube portion. The rotor tube portion includes a yoke tube portion and a hub tube portion. The yoke tube portion is located on a radially inside surface of the hub tube portion.

According to one embodiment, a magnetic disk device includes a controlled object, a controller which controls a motion of the controlled object, and loop shaping filters each connected in parallel to the controller. During a determination of coefficients of the loop shaping filters using a transfer function from outputs of the loop shaping filters to before an input of a disturbance affecting the controlled object, the first set of coefficients of each the loop shaping filter is determined by reflecting a frequency response of the other loop shaping filters, and the determined first sets of coefficients of the loop shaping filters are set to the loop shaping filters, respectively.

According to one embodiment, a magnetic disk device includes a controlled object, a controller which controls a motion of the controlled object, and loop shaping filters each connected in parallel to the controller. During a determination of coefficients of the loop shaping filters using a transfer function from outputs of the loop shaping filters to before an input of a disturbance affecting the controlled object, the first set of coefficients of each the loop shaping filter is determined by reflecting a frequency response of the other loop shaping filters, and the determined first sets of coefficients of the loop shaping filters are set to the loop shaping filters, respectively.

Various illustrative aspects are directed to a data storage device comprising a first spindle motor configured to rotate one or more disks in a first stack of disks, a second spindle motor configured to rotate one or more disks in a second stack of disks, and one or more processing devices configured to detect back electromotive force (BEMF) voltages generated by the first spindle motor and the second spindle motor. In other aspects the one or more processing devices can control speeds of the first spindle motor and the second spindle motor based on the detected BEMF voltages.

A base member of a spindle motor includes an upper surface and a lower surface, in which the base member is a casting, the upper surface includes a pin portion extending upward, the lower surface includes a first lower surface and a second lower surface positioned higher than the first lower surface, and the first lower surface and the second lower surface are adjacent to each other with a stepped portion interposed between the first lower surface and the second lower surface, the stepped portion increasing in height from the first lower surface to the second lower surface. The stepped portion has a uniform height difference, and when a tangential line is drawn to the stepped portion in a cross section passing through a central axis of the pin portion and extending perpendicular to the stepped portion in plan view, the tangential line extends through between a lower edge point of an outer periphery of the pin portion on a side of the second lower surface and a lower edge point of the outer periphery of the pin portion on a side of the first lower surface.

According to one embodiment, a disk device includes a plurality of recording media each including a recording layer and an actuator assembly including an actuator block rotatably supported around a rotation shaft, a plurality of arms extending from the actuator block, and suspension assemblies respectively attached to the arms and supporting respective magnetic heads. Of the plurality of arms, at least one arm has vibration characteristics different from those of the other arms.