Constrained Dimple Pad Damper for Disk Drive Sway Reduction
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Solution Overview
Problem
There is a need for improved load point structures in disk drive head suspensions that enhance performance, particularly in terms of damping sway gain and reducing dimple wear, while allowing for efficient manufacturing and compatibility with both single and dual-stage actuation configurations.
Innovation Solution
The implementation of a constrained load point structure featuring a dimple formed in the load beam that engages a viscoelastic damper, which includes a constraining layer and a viscoelastic layer, positioned between the load beam and the flexure, effectively damping sway and reducing wear by utilizing a unitary piece of stainless steel for the load beam, spring region, and encapsulant barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional dimple load point structure is used, then the suspension can transfer spring force and allow slider movement, but sway gain is insufficiently damped and dimple wear increases
Solution Approach 1:
The load point structure combines a rigid dimple (formed in the load beam) with a viscoelastic damper material positioned at the load point. This composite structure integrates the load-bearing function of the rigid dimple with the sway-damping function of the viscoelastic material, achieving both force transfer and sway reduction while minimizing wear through the cushioning effect of the viscoelastic layer.
Solution Approach 2:
The invention introduces a viscoelastic material with specific damping characteristics at the load point, changing the mechanical parameters of the suspension system. The viscoelastic material provides frequency-dependent damping that reduces sway gain by 8 to 11 decibels, while its compliant nature reduces contact stress and wear at the dimple interface.
2Reliability
If a constrained dimple pad damper structure is implemented, then sway gain is significantly damped, but the manufacturing complexity increases
Solution Approach 1:
The dimple and damper are combined into an integrated load point structure where the viscoelastic material is positioned within or adjacent to the dimple formed in the load beam. This merging eliminates the need for separate damping components and simplifies assembly, as the damper is constrained by the dimple geometry itself, reducing manufacturing complexity while maintaining effective sway damping.
Solution Approach 2:
The viscoelastic damper material acts as an intermediary between the load beam and the slider mounting region, absorbing vibrations and reducing sway. This intermediary element is strategically positioned at the load point where it can effectively dampen oscillations without interfering with the primary load transfer function, achieving simplified integration of damping functionality.
3Productivity
If a unitary piece of stainless steel is used for the load beam and spring region, then manufacturing efficiency is improved, but the damping performance may be insufficient
Solution Approach 1:
The unitary stainless steel load beam is combined with a viscoelastic damper material at the load point, creating a composite structure that leverages the manufacturing efficiency of the unitary metal component while adding the damping performance of the viscoelastic material. This composite approach maintains the structural integrity and manufacturing simplicity of the steel load beam while supplementing it with targeted damping functionality.
Solution Approach 2:
The viscoelastic damper is positioned locally at the load point region of the unitary stainless steel load beam, providing damping performance specifically where needed without requiring the entire load beam to be made of damped material. This local application of damping material maintains manufacturing efficiency while achieving the required damping performance at the critical load transfer interface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution achieves a significant damping of sway gain by 8 to 11 decibels, increases servo bandwidth by approximately 500 Hertz, and decreases dimple wear, while allowing for efficient manufacturing and compatibility with both single and dual-stage actuation configurations.
Implementation Method 1
a viscoelastic layer, positioned between the load beam and the flexure, effectively damping sway
Data Source
AI summary
A disk drive head suspension including a load beam, a flexure on the load beam, and a load point dimple extending from the load beam toward the flexure. A constrained damper is located on the flexure and is engaged by the load point dimple. The constrained damper includes a layer of viscoelastic material on the flexure, and a metal constraining layer on the viscoelastic material. The flexure can be a co-located dual stage actuated flexure that includes a motor, and the constrained damper can be located on the motor.