Sae Magnetics (h.k.) Limited

Yen Fu

Ellis T Cha

Chao-Hui Yang

Li-Yan Zhu

Qinghua Zeng

Manuel Hernandez

Hong Tian

Po-Kang Wang

Yaw-Shing Tang

Ben Hu

Zhu Feng

Xiaofeng Zhang

Chi Hung Yuen

Jeffery L Wang

David Hu

Hai Ming Zhou

Manny Hernandez

Yong Luo

Mannuel Hernandez

Gimbal designs are provided that minimize adverse dynamic performance of a HDD suspension, particularly subsequent to head-disk-interface (HDI) interactions. The improvement of operational performance can be seen in graphical representations of the vibrational modes of a gimbal mounted slider subsequent to such HDI interactions. Each gimbal design includes a ramp limiter formed as two separated arms connected by one or two transverse bars and a routing of conducting traces that relieves stress and minimally contacts these bars.

Gimbal mounted slider assembly with ramp limiter transverse bar

In a suspension in a hard disk drive, a gimbal with asymmetric dynamic properties, in which the two halves of the gimbal may have different stiffness distribution or inertia distribution. Structural difference between the two halves, or materials with different stiffness, may cause the different stiffness distribution or inertia distribution. When the suspension vibrates, the different stiffness and/or inertia distribution increase the friction between the gimbal and a load beam of the suspension, and increase the damping of the suspension.

Gimbal with assymmetric dynamic stiffness

Method and apparatus are presented for electrically coupling a slider to ground. In one embodiment, a bonding pad is provided on a side of the slider body separate from the bonding pad(s) used for read/write signals. This separate bonding pad is electrically coupled within the slider body to components that are to be coupled to ground. A separate conductor provided on the suspension (e.g., a trace, a flex circuit, etc.) may be electrically coupled to the separate bonding pad via gold ball bonding. The conductor is also coupled to ground in the hard-disk drive device (e.g., via the preamplifier). The use of the separated bonding pad and trace may negate the need to use a conductive adhesive to electrically ground the slider via its attachment to the tongue of a slider.

Method and apparatus for providing an additional ground pad and electrical connection for grounding a magnetic recording head

In a balanced head gimbal assembly for improved seeking performance, a slider having a magnetic head with a set of read elements to read data and a set of write elements to write data, an air-bearing surface, and a non-air-bearing surface is coupled to a suspension. The suspension includes a loadbeam, a flexure, and a balancing weight. The loadbeam is coupled to an actuator arm. The flexure, coupled to the loadbeam, has a window through which a dimple, coupled to the loadbeam, contacts a dimple contact point. The balancing weight, coupled to the flexure, has a configuration which permits alignment of a center of mass of the head gimbal assembly with the dimple contact point.

Method of reducing slider roll torque by balancing head gimbal assembly for improved seeking performance

Gimbal mounted slider assembly with transverse bars connecting inner edges of ramp limiter arms

A flexure with improved temperature sensitivity is disclosed. An embodiment of the present invention includes a bi-layered flexure that raises or lowers a read/write element a distance that is approximately equal to the distance of protrusion and retraction at varying temperatures.

Suspension with bi-layer flexure base whose layers have different coefficients of thermal expansion to eliminate thermally induced flying height variations

Balanced head gimbal assembly for improved seeking performance

An apparatus with a head gimbal assembly designed to reduce movement and rotation of components of the head gimbal assembly structure is disclosed. One embodiment head gimbal assembly may comprise a flexure including a ramp limiter, a suspension assembly further comprising a suspension tongue, a slider further comprising a magnetic head; and a load beam further comprising a lift tab; and a ramp further comprising a step to engage and support the ramp limiter and support and constrain the movement of the slider. In certain embodiments, the flexure may further comprise a flexure rail located at its end to reduce movement and rotation of the suspension tongue.

Suspension with locally strengthened gimbal

A gimbal design for a hard disk drive are disclosed. In one embodiment, a gimbal tongue is supported by a gimbal cross bar coupled to a suspension body by a pair of gimbal struts. A pair of grounding pads are mounted on either side of the leading edge of the gimbal tongue. A first limiter tab is coupled to the leading edge of the gimbal tongue and a second limiter tab is coupled to the trailing edge of the gimbal tongue. Notches on either side of the trailing edge limiter tab increase the strength of the tab. One or more cutouts allow the slider to be electrically coupled to bonding pads on the opposite side of the gimbal tongue. Angled slots at the juncture of the gimbal cross bar and the gimbal tongue relieve stress on the gimbal.

Gimbal design with solder ball bond pads and trailing edge limiter tab for a recording head

A loadbeam is locally stiffened by either, 1. the addition of strategically placed extra material to the loadbeam, 2. not removing material during the etching process to form the loadbeam, or 3. special forming, by crimping or bending, at specific sites on the beam. The use of local stiffening, when placed about the loadbeam dimple or between the dimple and flexure attachment points, with or without additional damping, can significantly improve the dynamical response of the loadbeam and eliminate vibrational modes of a slider mounted on the loadbeam during HDI interactions with disk surface asperities during disk drive operation.

Suspension with locally stiffened load beam

Suspension gimbal designs with better dynamic performances

In a system and method for a non-contact measurement of the fly height of a slider above a magnetic data storage medium using electrostatic force, a slider with a read/write head flies over a magnetic data storage medium. A series of distinct voltages are applied between the slider and the magnetic data storage medium, and corresponding read-back signals are recorded. Using the recorded read-back signals, coefficients for an empirical curve-fit equation are calculated. The coefficients are normalized and converted into a fly height measurement.

Non-contact measurement of slider fly height by electrostatic force

In a system and method for adjusting a static torque on a slider in a head-gimbal assembly, a substantially rigid mass is placed on an air-bearing surface (ABS) of a slider. A static attitude of the slider is measured, and an adjustment location and intensity for a flexure to yield a zero slider static attitude are calculated. The flexure is adjusted based on the measurement and calculations.

Adjustment of pitch and roll static torques in a disk drive head gimbal assembly

In a method and apparatus for testing a head-gimbal assembly (HGA), a HGA is placed in contact with force transducers mounted on a rotational stage. The force transducers are adjusted to position the transducers around a rotational center of the rotational stage. The rotational stage is rotated, and the torque and variations in torque exerted by the HGA on the force transducers during rotation are measured.

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San Jose, CA, United States of America

Yen Fu