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Reflex Clamp for Clamping Disks in Head Disk Assembly

IP.com Disclosure Number: IPCOM000047454D
Original Publication Date: 1983-Nov-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Tamhane, SK: AUTHOR

Abstract

Clamping magnetic disks in a head disk assembly (HDA) has historically been a problem inherently due to stringent functional requirements. Some of the more serious problems encountered so far are: 1. Thermal stresses due to different coefficients of thermal expansion of clamp material and disk material, causing high runout and surface normal acceleration X;. 2. Radial deflection of clamp under axial load imparts radial distortion to disks, causing disk runout and X;, high values of which adversely affect head flying characteristics and have been related to head crashes. 3. High variation of clamping loads due to stacking tolerance build-up. 4. High cost of intricate designs from expensive materials and involved manufacturing processes. 5.

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Reflex Clamp for Clamping Disks in Head Disk Assembly

Clamping magnetic disks in a head disk assembly (HDA) has historically been a problem inherently due to stringent functional requirements. Some of the more serious problems encountered so far are: 1. Thermal stresses due to different coefficients of thermal expansion of clamp material and disk material,

causing high runout and surface normal acceleration X;. 2. Radial deflection of clamp under axial load imparts radial distortion to disks, causing disk runout

and X;, high values of which adversely affect head

flying characteristics and have been related to head

crashes. 3. High variation of clamping loads due to stacking

tolerance build-up. 4. High cost of intricate designs from expensive

materials and involved manufacturing processes. 5. Assembly problems in maintaining alignment and adjusting for uniform axial loads. Stiffer spring

rates require more delicate alignment. Using a

floating clamp requires high axial load (at least

10,000 lbs.) to prevent disk slippage. Thus, all other

components have to be made heavier to withstand these

high loads - hub, spindle shaft, bearings, casting,

etc. Advantages of the Reflex Clamp 1. It is made of 7075 aluminum which has the same coefficient of thermal expansion as the disk substrate.

Thus, there is no problem of thermal stress which

adversely affects disk runout and X;. 2. The geometry of the reflex clamp, per se, offers minimum radial deflection under axial loading....