A spindle motor includes a base, a shaft arranged on the base and extending in a vertical direction, a stator having a coil defined by a wound conductive wire and arranged on an upper surface of the base, and a rotor rotatably supported around the shaft. The base has a through hole that penetrates the base from the upper surface to a lower surface. The conductive wire is drawn out to the lower surface side through the inside of the through hole. The through hole is sealed by a sealing material. The through hole includes a columnar lower column body and a columnar upper column body. The lower column body is arranged on the lower surface side of the base. A cross-sectional area of the upper column body orthogonal to an axial direction is smaller than a cross-sectional area of the lower column body orthogonal to the axial direction.

A motor driver circuit includes: an error detection amplifier configured to receive a current feedback signal indicating a drive current of a motor as an object to be driven and an analog command signal indicating a target amount of the drive current, and generate an analog error signal indicating an error between the drive current and the target amount of the drive current; an A/D converter configured to convert the analog error signal generated by the error detection amplifier into a digital error signal; a digital compensator configured to generate a digital control amount based on the digital error signal output by the A/D converter; a D/A converter configured to convert the digital control amount into an analog control signal; and an output stage configured to supply a drive signal according to the analog control signal to the motor.

A dual disk spindle motor hard disk drive includes a first portion having a first spindle motor and a first disk media stack mounted thereon and housed in a first enclosure, and a second portion having a coaxial second spindle motor and a second disk media stack mounted thereon and housed in a second enclosure, where the second portion further includes both the first actuator and head sliders corresponding to the first disk stack as well as the second actuator and head sliders corresponding to the second disk stack. The first and second portions are coupled together such that the open sides of the enclosures mate, referred to herein as a clamshell configuration, and each separate spindle motor is configured to operate independently of the other. With independent control of multiple spindle motors, various control functions may be utilized to address power consumption and temperature control.

A base plate is a portion of a housing of a disk drive apparatus, including a base body being a casting product, and an electrodeposition coating film covering at least a portion of a surface of the base body. The base body includes a bottom plate rectangular as viewed from an axial direction, a pivot post, and a protrusion. The bottom plate extends perpendicular to a rotation axis of a disk that extends vertically and a swing axis of a head that is disposed in a different position from the rotation axis and that extends vertically. The head reads or writes information from or to the disk. The pivot post protrudes upward from an upper surface of the bottom plate along the swing axis. The protrusion is provided protruding radially outward from a peripheral surface of the pivot post and protruding to the upper surface of the bottom plate.

A magnetic tunneling junction (MTJ) structure is described. The MJT structure includes a stress modulating layer on a first electrode layer, where a material of the stress modulating layer is different from a material of the first electrode layer. The MJT structure further includes a MTJ material stack on the stress modulating layer. And the MJT structure further includes a second electrode layer on the MTJ material stack. The stress modulating layer reduces crystal growth defects and interfacial defects during annealing and improve the interface lattice epitaxy. This will improve device performance.

A hub of this motor includes a hub annular portion being annular and arranged above a stator, and a flange portion arranged to extend radially outward from the hub annular portion, and including an upper surface on which an annular member is arranged. A yoke includes a first yoke cylindrical portion to which a magnet is fixed; a yoke annular portion arranged to extend radially inward from an upper end of the first yoke cylindrical portion, and including an upper surface arranged opposite to a lower surface of the hub; and a second yoke cylindrical portion arranged to extend axially upward from a radially inner end portion of the yoke annular portion. An inner circumferential surface of the hub annular portion and an outer circumferential surface of the second yoke cylindrical portion are fixed to each other at an engagement portion arranged radially inward of a radially inner end portion of each of coils.

A stationary portion of a spindle motor includes a stator portion and an outside surface. The stator portion includes a stator core and coils. The outside surface extends in an axial direction parallel or substantially parallel to a central axis, and is centered on the central axis. The spindle motor includes a fixing portion at which an inside surface of the stator core and the outside surface are fixed to each other. The fixing portion includes a first press fit portion, a second press fit portion, and a gap arranged therein. The gap is located between the first press fit portion and the second press fit portion. The second press fit portion is located above the first press fit portion. At least a portion of the second press fit portion is located above a middle of the stator core in the axial direction.

A stationary portion of a spindle motor includes a stator portion and an outside surface. The stator portion includes a stator core and coils. The outside surface extends in an axial direction parallel or substantially parallel to a central axis, and is centered on the central axis. The spindle motor includes a fixing portion at which an inside surface of the stator core and the outside surface are fixed to each other. The fixing portion includes a first press fit portion, a second press fit portion, and a gap arranged therein. The gap is located between the first press fit portion and the second press fit portion. The second press fit portion is located above the first press fit portion. At least a portion of the second press fit portion is located above a middle of the stator core in the axial direction.

A spindle motor includes a base, a shaft arranged on the base and extending in a vertical direction, a stator having a coil defined by a wound conductive wire and arranged on an upper surface of the base, and a rotor rotatably supported around the shaft. The base has a through hole that penetrates the base from the upper surface to a lower surface. The conductive wire is drawn out to the lower surface side through the inside of the through hole. The through hole is sealed by a sealing material. The through hole includes a columnar lower column body and a columnar upper column body. The lower column body is arranged on the lower surface side of the base. A cross-sectional area of the upper column body orthogonal to an axial direction is smaller than a cross-sectional area of the lower column body orthogonal to the axial direction.

A method of tuning a notch filter in a data storage device (DSD) including the notch filter and a shock detection system includes: adjusting pulse width modulator (PWM) frequency settings of a spindle drive signal; detecting a maximum noise level of an output signal of the shock detection system while adjusting the PWM frequency settings; and selecting a notch filter frequency corresponding to a PWM frequency setting at which the maximum noise level of the output signal of the shock detection system is detected.