Head Gimbal Assembly Weld Dimples for Z-Height Stability
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Solution Overview
Problem
Existing head gimbal assemblies (HGAs) in hard disk drives (HDDs) experience non-linear variations in pitch and roll stiffness with changes in Z-height, leading to instability and potential data reading/writing errors due to mechanical vibrations matching natural resonant frequencies.
Innovation Solution
Incorporation of weld dimples on the load beam with a flat base, positioned to align weld locations with the gimbal tongue, minimizing flexure stretching and maintaining consistent pitch and roll stiffness across varying Z-heights, thereby stabilizing the slider's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the load beam uses conventional welding without dimples, then the structure is simpler, but the pitch and roll stiffness vary non-linearly with Z-height causing instability
Solution Approach 1:
The patent applies local quality by introducing weld dimples at specific locations on the load beam where stiffness control is needed. The dimples are positioned to locally modify the flexure stretching characteristics without affecting the entire load beam structure uniformly. This localized modification allows independent control of pitch and roll stiffness characteristics.
Solution Approach 2:
The weld dimples change the geometric parameters of the load beam by creating controlled recesses with specific dimensions (depth, diameter, spacing). These parameter changes modify the flexure stretching behavior and stiffness characteristics. The dimple depth, diameter, and spacing are optimized to achieve linear stiffness-Zheight relationships and eliminate non-linear variations.
2Adaptability or versatility
If the flexure is stretched more to accommodate Z-height variations, then the slider can move freely, but the stiffness becomes non-linear and unstable
Solution Approach 1:
The weld dimples are pre-formed on the load beam during manufacturing, creating ready-made compensation features that automatically adjust flexure stretching before operation begins. The dimples are positioned and dimensioned to preemptively account for Z-height variations, ensuring that the flexure stretches in a controlled manner that maintains linear stiffness characteristics throughout the range of motion.
Data Source
AI summary
A data storage device includes a data storage disk, an actuator arm, a load beam attached to the actuator arm, and a flexure attached to the load beam. The disk has a read/write surface defining an x-y plane, and the actuator arm is movable parallel to the x-y plane. The load beam supports a slider that carries a head that is configured to interact with the read/write surface. The load beam includes a first dimple that extends toward the read/write surface and has a flat base. The flexure is attached to the load beam at the flat base of the first dimple and is attached to the slider. The flexure is substantially parallel to the x-y plane between the flat base of the dimple and the slider. In another aspect, an actuator arm assembly includes a load beam with weld dimples.