Western Digital Technologies, Inc.

Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

Manoj Keshavan

Jung-Seo Park

Hitoshi Shindo

Siddhesh Vivek Sakhalkar

Jeffrey Kerner

Yanning Liu

Jr-Yi Shen

Andre Sirilutporn Chan

Hiromitsu Masuda

Robert Carl Reinhart

Shigenori Takada

A hard disk drive includes multiple actuator assemblies, each of which includes a head-stack assembly (HSA) including an end-arm to which a single head-gimbal assembly (HGA) is coupled, where this end-arm is configured with a notch along one side and a triangular or quadrilateral-shaped through-hole at a root-side of the end-arm, and where the HSA further includes a plurality of other end- and inner-arms to each of which two HGAs are coupled and none of which have a through-hole near their root. The single-HGA end-arm may be further configured with an outer damper having a through-hole coincident with the end-arm through-hole, such that the through-hole of the end-arm is not covered by this damper, and an inner damper having no through-hole, such that the through-hole of the end-arm is covered by this damper. Gains are thereby better matched across all HGAs for problematic arm and system modes.

Management of actuator dynamics in a multiple actuator hard disk drive with an unequal number of heads on the two outer arms of each actuator

Control circuitry is disclosed configured to control inner fine actuators of a first plurality of inner actuator arms and independently control a first outer fine actuator of a first outer actuator arm. Inner fine actuators of a second plurality of inner actuator arms are controlled while independently controlling a second outer fine actuator of a second outer actuator arm. Each actuator arm comprises at least one head configured to access a disk surface of a disk.

Data storage device independently driving outer and inner fine actuators

A multi-actuator data storage device such as a hard disk drive may include a lower actuator-pivot-VCM assembly including a lower pivot shaft and a lower motor assembly, an upper actuator-pivot-VCM assembly including an upper pivot shaft and an upper motor assembly, and a central support structure or plate sandwiched between the lower and upper pivot shafts and the lower and upper motor assemblies. The central support structure may be shaped to make contact with the motor assemblies only at discrete assembly locations and to make contact with the pivot shafts at opposing raised pads. Viscoelastic dampers may be adhered to the central support structure at the contact locations to dampen motor vibrational modes and/or to reduce the amplitude of vibration transmitted among the actuator-pivot assemblies. Such an assembly may increase the tilt and in-phase butterfly mode frequencies and decrease the gains of the tilt and coil torsion modes.

Central support for improved structural dynamics of actuators in a multi-actuator hard disk drive

An actuator pivot shaft assembly for a multi-actuator data storage device may include one or more annular grooves extending radially inward from an outer surface of the pivot shaft, thereby desirably weakening or structurally decoupling the shaft between the actuators, to assist with inhibiting transmission of vibration between the actuators during operation. The shaft assembly may further include an elastomeric damper positioned within the annular groove(s), to damp transmission of vibrational forces between the actuators through the shared shaft.

Reducing vibration transmission in a dual actuator disk drive utilizing a single pivot shaft

A split-shaft pivot assembly for a dual-actuator data storage device may include a first pivot shaft around which a first bearing assembly is affixed, a second pivot shaft around which a second bearing assembly is affixed, and whereby the two pivot shafts are coupled together by way of an interface spacer between the shafts. The interface spacer may include a receiving structure at each end of a housing, for receiving an end of a respective shaft, and an annular slot circumscribing the housing between the receiving structures, where an elastomeric damper is positioned within the slot. The interface spacer housing may be composed of a material having a lower elastic modulus than the material of which the shafts are composed, thereby making the interface spacer relatively compliant. Such features may serve to inhibit and/or damp transmission of vibrational energy among the actuators through the shared split-shaft.

Split-shaft pivot with interface spacer for a dual-actuator hard disk drive

A split-shaft pivot assembly for a dual-actuator data storage device may include a first pivot shaft having a threaded stud extending from one end and an attachment flange at the other end, and a second pivot shaft having a threaded bore at one end a structurally equivalent attachment flange at the other end, where the two pivot shafts are attached to each other by threading the stud into the bore. A first bearing assembly may be affixed with a first preload around the first pivot shaft, and a second bearing assembly may be affixed with a second different preload around the second pivot shaft. The pivot assembly may further include an elastomeric damper positioned within an annular groove formed in, and around the threaded stud of, the first pivot shaft. Such features may serve to inhibit and/or damp transmission of vibrational energy among the actuators through the shared split-shaft.

Split-shaft pivot for a dual-actuator hard disk drive

An actuator pivot assembly for a multi-actuator shared shaft data storage device may include a shared pivot shaft around which a first rotary actuator assembly is coupled, with a first bearing assembly interposed therebetween with a first bearing preload, and around which a second rotary actuator assembly is coupled, with a second bearing assembly interposed therebetween with a second different bearing preload. Furthermore, the first bearing assembly may have a first bearing span and the second bearing assembly may have a second bearing span that is different from the first bearing span. Each of the foregoing bearing features may thereby assist with spacing apart the structural resonance frequencies of the actuator assemblies to inhibit transmission of vibration between the actuators during operation.

Techniques for reducing dynamic coupling of system modes in a dual actuator hard disk drive

A contamination mitigation cap for a hard disk drive actuator pivot assembly is affixed to the rotatable carriage of an actuator assembly and, in conjunction with a bearing hub cap, forms a labyrinth seal for retaining pivot bearing contamination. Consequently, the risk of such contamination migrating to the head-disk interface and causing read/write problems is mitigated, especially in the context of sleeveless pivot bearing assemblies. Various shapes of the contamination mitigation cap may be utilized, such as a flat ring, an S-section ring, and an L-section ring.

Contamination mitigation cap for a hard disk drive actuator pivot assembly

Approaches to improving actuator settle time by damping vibrations resulting from coil modes, such as with a voice coil actuator in a hard disk drive, include a single-piece damper plate coupled to the voice coil actuator yoke. The damper plate may be a single U-shaped piece of metal that covers the area of the yoke that experiences the maximum strain energy during operation, between the voice coil and the pivot bearing housing.

Single-piece yoke damper for voice coil actuator

An actuator assembly for a magnetic storage device includes a top surface and a bottom surface that opposes the top surface. The actuator assembly also includes a first constraining layer that is secured to the top surface by a first adhesive layer. The first adhesive layer is positioned between the top surface and the first constraining layer. Additionally, the actuator assembly includes a second constraining layer that is secured to the bottom surface by a second adhesive layer. The second adhesive layer is positioned between the bottom surface and the second constraining layer. At least one of (i) the first constraining layer is configured differently than the second constraining layer; and (ii) the first adhesive layer is configured differently than the second adhesive layer.

Dampers for actuator assembly of hard disk drive

A post-assembly head/disk offset adjuster is disclosed. One embodiment provides a housing and at least one disk coupled with the housing. In addition, an adjustable pivot plate is coupled with the housing such that access to at least one adjustment point of the adjustable pivot plate is provided regardless of a state of assembly of the hard disk drive. Furthermore, an actuator is coupled with the adjustable pivot plate. In so doing, an adjustment to the at least one adjustment point of the adjustable pivot plate results in an adjustment to the actuator regardless of the state of assembly of the hard disk drive.

Post-assembly head/disk offset adjuster

Outer arm constrained layer dampers to improve actuator dynamics are disclosed. One embodiment provides a housing and disk pack mounted to the housing and having a plurality of disks that are rotatable relative to the housing. In addition, an actuator is coupled to the housing, the actuator having a plurality of suspensions arms for reaching over the plurality of disks. A first damper is coupled with an outside (or inside) portion of a top outside suspension arm of the plurality of suspensions arms. In addition, a second damper is coupled with an outside (or inside) portion of a bottom suspension arm of the plurality of suspensions arms. In so doing, vibration modes involving deformation of the top suspension arm and the bottom suspension arm are damped.

Outer actuator arm constrained layer dampers

An airflow diverter is used to overcome the adverse effect of flow-induced vibration of a disk drive pivot actuator. The diverter may be formed as a separate component or as an integral portion of the flex stiffener or the actuator itself. The invention streamlines the actuator to the incoming airflow and helps reduce the torque disturbance to the actuator as it reduces the sail or parachute effect. This helps reduce power consumption due to a lower drag from the actuator assembly. The contour of the flow deflector is designed to conform closely to the curvature of the disk boundaries when the actuator is rotated to the ID position on the disk. This design serves as a shroud around the disk stack which further helps to reduce power by preserving flow momentum.

In a disk drive apparatus having a diverter for providing streamlined contour and reduced axial flow at the actuator attachment interface between a flexible cable and flexure

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San Jose, CA, United States of America

Manoj Keshavan