Hard Disk Head Suspension Limiter for Flexure Buckling Prevention
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Solution Overview
Problem
The contact start/stop (CSS) method for hard disk drives experiences significant frictional forces and deformation issues when the disk reverses direction, leading to read/write errors and potential buckling of the flexure, which existing solutions fail to adequately address.
Innovation Solution
A head suspension with a limiter formed on the flexure or load beam that restricts deformation of the tongue caused by frictional forces, maintaining the correct pitch angle and preventing buckling by contacting the tongue when it displaces beyond a certain point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the CSS method is used to retract the slider to a CSS area on the hard disk, then the slider can be retracted without complex mechanisms, but large frictional forces occur between the slider and hard disk causing deformation and read/write errors
Solution Approach 1:
The CSS area is segmented into a first CSS area with first irregularities and a second CSS area with second irregularities. The head suspension is segmented into a first region with a first friction coefficient and a second region with a second friction coefficient. This segmentation allows different friction characteristics in different zones to manage frictional forces during slider retraction and positioning.
Solution Approach 2:
Different regions of the hard disk surface are given different local qualities through distinct irregularity patterns. The first CSS area has first irregularities optimized for initial retraction, while the second CSS area has second irregularities optimized for final positioning. Similarly, different regions of the head suspension have different friction coefficients to control frictional forces locally.
2Productivity
If the fly height of the slider is minimized to increase storage capacity, then more data can be stored, but frictional force between the slider and hard disk increases
Solution Approach 1:
The hard disk surface is given different local qualities in different CSS areas through distinct irregularity patterns. The first CSS area has first irregularities that reduce friction during initial retraction, while the second CSS area has second irregularities that control friction during final positioning, allowing low fly height operation without excessive friction.
3Reliability
If the hard disk surface is roughened to prevent slider attraction, then the slider can be prevented from sticking to the disk, but frictional force increases causing deformation
Solution Approach 1:
The CSS area is segmented into two distinct zones with different irregularity characteristics. The first CSS area provides initial detachment with controlled friction, while the second CSS area provides final positioning with optimized friction characteristics, balancing slider detachment reliability with friction reduction.
Solution Approach 2:
Different local qualities are applied to different regions of the CSS area through distinct irregularity patterns. The first irregularities in the first CSS area provide detachment functionality, while the second irregularities in the second CSS area provide positioning functionality with controlled friction.
4Reliability
If a limiter is added to restrict tongue deformation, then buckling can be prevented, but device complexity increases
Solution Approach 1:
The limiter function is merged with the existing friction reduction structure. The same structural element that reduces frictional forces also serves as the limiter that prevents tongue deformation and flexure buckling, eliminating the need for separate limiter components.
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 limiter effectively limits deformation within a given range, preventing buckling and ensuring accurate read/write operations by maintaining the slider's pitch angle, thus enhancing the reliability of data transfer in hard disk drives.
Implementation Method 1
frictional forces produced between a hard disk and a slider when the hard disk reversely turns
Data Source
AI summary
A head suspension restricts deformation of a flexure caused by frictional force produced between a hard disk and a slider when the hard disk turns in a reverse direction. The head suspension has a load beam resiliently supported with a base. The base is supported with an arm that is turned around an axis. The load beam applies load onto a head having a slider to write and read data to and from the hard disk. The flexure is attached to the load beam and has a tongue that supports the slider. The flexure is provided with a limiter that limits displacement of the tongue due to frictional force produced between the hard disk and the slider when the hard disk is reversely turned. The limiter is on the base side and faces a free end of the tongue. The limiter is integrally formed from a part of the flexure, to face the free end of the tongue.