According to one embodiment, a head suspension assembly includes a support plate, a wiring member on the support plate, a head, and a piezoelectric element on the wiring member. The wiring member includes a metal plate and a multilayered member including a first insulating layer, a conducting layer, a second insulating layer, and connection pads formed from the conducting layer. Each of the connection pads is overlaid on a recess formed in the first insulating layer, so as to form a recessed portion along the recess, and the second insulating layer includes an opening opposing each of the connection pads. The piezoelectric element is connected to the connection pads by a conductive adhesive filled in the openings and the recessed portions of the connection pads.

An approach to a piezoelectric (PZT) device, such as a hard disk drive microactuator, includes one or more layers of poled PZT material, with top and bottom surfaces coupled with respective electrode layers coupled with a power source to drive the active PZT layer(s). The electrode layers have different thicknesses, where the particular thicknesses may be configured to mitigate the variation of out-of-plane motion or bending associated with operational variations in the z-height between a corresponding actuator arm and recording medium and, likewise, the phase variation of flexure vibration.

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal for a particular head of the victim actuator is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the particular head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

In a multi-actuator drive, the effect of moving a first actuator (the so-called “aggressor actuator”) in on a second actuator (the so-called “victim actuator”) is reduced or compensated for. A victim feedforward signal for a particular head of the victim actuator is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator. The feedforward signal is configured to compensate for disturbances to the victim microactuator caused by VCM commands provided to the aggressor actuator. The feedforward signal is based on a transfer function that models commands added to the victim microactuator, which is coupled to the particular head of the victim actuator, as a function of the aggressor VCM control signal applied to the aggressor actuator.

A multi-layer piezoelectric microactuator assembly has at least one poled and active piezoelectric layer and one poled but inactive piezoelectric layer. The poled but inactive layer acts as a constraining layer in resisting expansion or contract of the first piezoelectric layer thereby reducing or eliminating bending of the assembly as installed in an environment, thereby increasing the effective stroke length of the assembly. Poling only a single layer would induce stresses into the device; hence, polling both piezoelectric layers even though only one layer will be active in use reduces stresses in the device and therefore increases reliability.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a first actuator that moves the magnetic head to a predetermined position on the magnetic disk, a second actuator that is provided in the first actuator and adjusts a position of the magnetic head, a control unit that controls operations of the first actuator and the second actuator, and a storing unit that stores a coefficient of an approximation polynomial calculated based on an approximation formula for approximating voltage dependency of a gain of the second actuator. When controlling the operation of the second actuator, the control unit calculates the gain amplitude of the second actuator from the approximation polynomial in which the coefficient is used and amplitude of a voltage input to the second actuator.

An approach to a piezoelectric (PZT) device, such as a hard disk drive microactuator, includes one or more layers of poled PZT material, with top and bottom surfaces coupled with respective electrode layers coupled with a power source to drive the active PZT layer(s). The electrode layers have different thicknesses, where the particular thicknesses may be configured to mitigate the variation of out-of-plane motion or bending associated with operational variations in the z-height between a corresponding actuator arm and recording medium and, likewise, the phase variation of flexure vibration.

According to one embodiment, a disk device includes two magnetic disks opposing each other at intervals of 1.2 to 1.5 mm, and at least two suspension assemblies movable respectively between the two magnetic disks. Each of the suspension assemblies includes a base plate, a load beam extending from the base plate, a tab extending from a distal end of the load beam, a wiring member on the load beam and the base plate, including a gimbal portion, and a magnetic head on the gimbal portion, abutting on a dimple of the load beam via the gimbal portion. The ratio of a distance from a bendable location of the load beam to a center of the dimple with respect to a distance from the center of the dimple to a tip of the tab is 2.8 to 3.8.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a first actuator that moves the magnetic head to a predetermined position on the magnetic disk, a second actuator that is provided in the first actuator and adjusts a position of the magnetic head, a control unit that controls operations of the first actuator and the second actuator, and a storing unit that stores a coefficient of an approximation polynomial calculated based on an approximation formula for approximating voltage dependency of a gain of the second actuator. When controlling the operation of the second actuator, the control unit calculates the gain amplitude of the second actuator from the approximation polynomial in which the coefficient is used and amplitude of a voltage input to the second actuator.

According to one embodiment, a suspension assembly includes a support plate including a distal end and a proximal end portion, a wiring member including a gimbal portion and provided. on the support plate, and a magnetic head mounted on the gimbal portion. The gimbal portion includes a first end portion located on a side of the proximal end portion with respect to the magnetic head and welded to the support plate, a second end located on a side of the distal end portion with respect to the magnetic head and welded to the support plate, a tongue portion on which the magnetic head is mounted, located between the first end portion and the second end portion, and supported so as to be displaceable relative to the support plate, and a limiter opposing the tongue portion with a gap.