HDD Damper Plate Splitter for Vortex Shedding Control

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Solution Overview

Problem

In hard disk drives (HDDs), the gas flow generated during operation can cause unwanted flow-induced vibration (FIV), leading to track misregistration (TMR) due to the interaction with the disk stack and head stack assembly, and existing damper plates face challenges in effectively controlling vortex shedding and manufacturing limitations.

Innovation Solution

The use of a damper plate with a splitter mechanism that disrupts vortex shedding by incorporating a thinner splitter portion extending from the main body, which is strategically positioned to control secondary gas flow and reduce turbulence, thereby creating a more streamlined gas flow and minimizing FIV.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional damper plate is used to control gas flow, then manufacturing is simplified, but vortex shedding and flow-induced vibration are not effectively controlled

Engineering Contradiction:

Improvevortex shedding intensityVSAvoiddamper plate structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The damper plate is segmented into a main body and a splitter portion that extends from the main body. This segmentation allows the splitter to specifically address vortex shedding control while the main body maintains gas flow management, resolving the contradiction between effective vortex control and structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The splitter portion acts as an intermediary element between the gas flow and the main damper plate body. It disrupts the formation of vortices by modifying the flow pattern before it interacts with the main body, thereby reducing vortex shedding intensity without requiring complete redesign of the entire damper plate structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If gas flow is allowed to interact with the disk stack, then the gas bearing slider can function, but flow-induced vibration and track misregistration occur

Engineering Contradiction:

Improvegas bearing slider functionVSAvoidhead positioning accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The damper plate design applies local quality modification by adding the splitter portion at a specific location where vortex formation occurs. This localized modification controls the gas flow characteristics in the critical region near the disk stack, reducing FIV and improving head positioning accuracy while maintaining overall gas bearing functionality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The splitter portion performs preliminary anti-action by disrupting vortex formation before the gas flow can interact with the disk stack and cause FIV. By pre-modifying the flow pattern, the splitter prevents the harmful interaction that would lead to track misregistration, while still allowing necessary gas flow for slider operation.

Inventive Principle:

Principle #9Preliminary anti-action

3Strength

If the splitter portion is made thicker, then structural strength is improved, but vortex shedding control effectiveness is reduced

Engineering Contradiction:

Improvesplitter portion strengthVSAvoidvortex shedding control

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The design optimizes the splitter portion thickness as a critical parameter, balancing it to achieve both adequate structural strength and effective vortex control. The thickness is specifically tuned so that the splitter is thin enough to effectively disrupt vortex formation but thick enough to maintain structural integrity under operational conditions.

Inventive Principle:

Principle #35Parameter changes

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 configuration significantly reduces the intensity of vortex shedding and FIV, resulting in improved head positioning accuracy and reduced track misregistration, while also addressing manufacturing and operational concerns related to damper plate design.

Implementation Method 1

controlling the vortex shedding associated with a hard disk drive damper plate

Methodology Applied

Scientific EffectVortex shedding: Kármán Vortex Street

Implementation Method 2

gas flow is generated. Indeed, the air bearing slider (or, generally, gas bearing slider) on which the read-write head is housed relies on such gas flow

Methodology Applied

Scientific EffectGas flow: Convection

Implementation Method 3

such gas flow generated within an HDD can have detrimental effects when impinging upon or interacting with the disk stack and the head stack assembly (HSA), for example, such as by contributing to imparting unwanted flow induced vibration (FIV) upon the disks and/or HSA

Methodology Applied

Scientific EffectFlow-induced vibration: Flutter

Data Source

PatentUS20190139582A1Control Of Vortex Shedding Associated With A Hard Disk Drive Damper Plate

Publication Date: 2019.05.09 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A hard disk drive damper plate comprises a planar main body having a generally rectangular cross-section and a splitter portion extending away from the main body in a radial direction. The splitter portion operates to disrupt vortex shedding corresponding to secondary gas flow associated with the planar main body. Various embodiments involve the length, thickness, and shape of the splitter portion, as well as how much of the planar main body may be provisioned with such a splitter portion.