Disk Drive Suspension Dimple Convex Surface Phase Delay Control
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Solution Overview
Problem
In disk drives, the slider fails to follow the undulations of the disk surface quickly enough, leading to potential interference and friction with the disk, which can cause hot spots or even scratching, due to significant changes in pitch angle and phase delay during disk rotation.
Innovation Solution
A disk drive suspension design that incorporates a dimple portion with a convex surface and a slider mounting portion, where the flexure pitching resistance (Fpr) is minimized, and the phase delay of the slider is kept below 20° or less, by optimizing the radius of curvature of the convex surface and the flexure pitching resistance, to prevent interference between the slider and the disk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the slider mounting portion swings about the convex surface of the dimple portion with a large radius of curvature, then the slider can follow disk undulations more smoothly, but the phase delay increases causing the slider to fail to track undulations quickly enough
Solution Approach 1:
The patent applies parameter changes by optimizing the radius of curvature of the convex surface within a specific range (0.04mm to 0.15mm) and controlling the flexure pitching resistance (Fpr) to achieve a phase delay of 20° or less. This balances the slider's response speed and tracking accuracy by adjusting geometric and mechanical parameters of the suspension system.
2Stability of the object's composition
If the flexure pitching resistance (Fpr) is increased, then the slider mounting portion is more stable during swinging, but the phase delay increases causing interference between slider and disk
Solution Approach 1:
The patent controls the flexure pitching resistance (Fpr) within a specific parameter range to achieve optimal performance. By adjusting this mechanical parameter, the system maintains slider mounting stability while keeping phase delay at 20° or less, preventing harmful interference and friction between the slider and disk surface.
3Reliability
If the radius of curvature of the convex surface is increased, then the contact between slider mounting portion and dimple portion is more stable, but the slider cannot respond quickly to disk undulations
Solution Approach 1:
The patent optimizes the radius of curvature of the convex surface within a specific range (0.04mm to 0.15mm) to balance contact stability and response speed. This parameter optimization ensures that the slider mounting portion maintains stable contact with the dimple portion while responding quickly enough to track disk undulations with phase delay of 20° or less.
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
The suspension effectively suppresses interference between the slider and the disk by maintaining a phase delay of 20° or less, ensuring smooth tracking of undulations and preventing excessive proximity, thereby reducing friction and contact issues.
Implementation Method 1
The slider mounting portion is elastically supported by a gimbal component such as an outrigger. The slider mounting portion is swung about the convex surface of the dimple portion.
Implementation Method 2
When a disk is rotated, air flows between the leading end of the slider and the trailing end of the slider. As a result, an air bearing is formed.
Data Source
AI summary
According to one embodiment, a suspension includes a load beam having a dimple portion and a flexure having a slider mounting portion. The dimple portion has a convex surface in contact with the slider mounting portion. The slider mounting portion is swingably supported by a gimbal component member. The radius of curvature of the convex surface is less than 0.15 mm. The flexure pitching resistance acting on the contact portion when the slider mounting portion swings in the pitching direction is 0.005 N or less. The phase delay of the slider mounting portion in the pitching direction relative to an undulation of a rotating disk is 200 or less.