AMEETANA
`[11] Patent Number:
`5,617,274
`[19]
`United States Patent
`Ruiz
`[45] Date of Patent:
`Apr. 1, 1997
`
`
`[54] LOW PROFILE INTEGRAL FLEXURE FOR
`CLOSELY PACKED DISKSIN A DISK DRIVE
`ASSEMBLY
`
`5,504,640
`5,530,605
`5,530,606
`
`4/1996 Hagen sccecsscsssesstusssuneusee 360/104
` 360/104
`6/1996 Hamaguchi etal.
`
`. 360/104
`6/1996 Baasch ct al.
`..............
`
`[75]
`
`[73]
`
`[21]
`
`[22]
`
`[51]
`[52]
`[58]
`
`[56]
`
`Inventor: Oscar J. Ruiz, San Jose, Calif.
`
`Assignee:
`
`International Business Machines
`Corporation, Armonk, N.Y.
`
`Appl. No.: 585,983
`
`Jan. 12, 1996
`Filed:
`
`. GIB 5/60
`Int. CL® ....
`
`wee 360/104
`US. Cl......
`
`Field of Search .....
`veneer 360/97.01, 98.01,
`360/104-106
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`...
`
`secon 360/103
`8/1988 Ainslie et al.
`4,761,699
`-- 360/104
`1/1989 Levy et al.
`...
`4,797,763
`.. 360/104
`2/1991 Erpelding etal.
`4,996,623
`360/104
`5/1992 Khan et al.
`..
`5,115,363
`360/104
`8/1992 Zarouri et al.
`5,138,507
`360/104
`2/1993 Blaeseret al.
`5,187,625
`360/104
`3/1993 Blaeseret al.
`5,198,945
`360/104
`7/1993
`5,225,950
`360/104
`1/1994
`5,282,102
`360/104
`1/1994 Hatch et al.
`5,282,103
`..-- 360/104
`7/1994 Johnson etal
`5,331,489
`. 360/104
`..
`7/1994 Prentice et al.
`5,333,085
`360/104
`5,377,064 12/1994 Yaginuma etal.
`360/104
`5,381,288
`1/1995 Karam,I...
`360/104
`5,428,489:
`6/1995 Takamure etal.
`
`360/104
`5,428,490
`6/1995 Hagen .......0..
`360/104
`.
`5,452,158
`9/1995 Harrison et al.
`
`eeessseoeeees 360/104
`5,491,597
`2/1996 Bennin et al...
`
`.
`
`
`
`
`FOREIGN PATENT DOCUMENTS
`0487914A2
`6/1992
`European Pat. Off. .
`59-207065
`11/1984
`Japan .
`5-36035
`2/1993
`a 360/104
`Japan .
`5-314630
`11/1993
`- 360/104
`Japan ......
`WIPO .
`WO94/12974
`6/1994
`W094/16438
`7/1994 WIPO.
`W094/24664 10/1994 WIPO.
`
`OTHER PUBLICATIONS
`
`“Type 1650 Product Summary”, Hutchinson Technology
`Inc., Sep. 1992, pp. 1-9.
`
`Primary Examiner—Robert S. Tupper
`Assistant Examiner—Jefferson Evans
`Attorney, Agent, or Firm—Baker, Maxham,Jester & Meador
`
`[57]
`
`ABSTRACT
`
`A load beam having an integral flexure for coupling a
`transducer head in a disk drive assembly. The integral
`flexure includes a pair of bending bars connected to the main
`body of the load beam, a floating pad connected to the
`bending bars, and a dimple formed on the floating pad. A
`torsion bar connects the floating pad with a bonding pad. The
`transducer head is adhesively coupled to the bonding pad,
`and rests upon the dimple. In operation, the dimple provides
`preload and allows gimbaling along the pitch and roll axis,
`but yaw movementis substantially prevented by the geom-
`etry of the load beam design. The integral Hexure has a low
`profile and will
`fit within a very small space between
`closely-spaceddisks in a stacked multiple disk drive system.
`
`22 Claims, 8 Drawing Sheets
`
`362
` pitch axis
`
`
`
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`

`

`U.S. Patent
`
`Apr. 1, 1997
`
`Sheet 1 of 8
`
`5,617,274
`
`CONTROLLER
`HosT
`|.
`
`160 SYSTEM|189UNIT
`
`
`
`ACTUATOR
`CONTROL/
`DRIVE
`
`READ/
`WRITE
`CHANNEL
`
`SPINDLE
`CONTROL/
`DRIVE
`
`170
`
`140=132 ij 150 452
`
`f]
`—
`} tr
`Ho pe t2
`
`14
`
`"
`
`\ asah 112
`{| Ss112
`
`112
`
`120
`
`110
`
`FIG. 2
`
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`

`

`U.S. Patent
`
`Apr. 1, 1997
`
`Sheet 2 of 8
`
`5,617,274
`
`N i
`
`n
`
`©oO
`
`Qo
`w
`
`“NS
`
`©e
`
`y
`
`
`
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`

`

`U.S. Patent
`
`Apr. 1, 1997
`
`Sheet 3 of 8
`
`362
`
`pitch axis
`629 630
`
`632
`
`5,617,274
`
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`

`

`U.S. Patent
`
`Apr. 1, 1997
`
`Sheet 4 of 8
`
`5,617,274
`
`Compressive Contact Stress at Dimple Interface
`
`(ksi)
`MaxCompressiveStress
`
`
`
`250
`
`ND oO Oo
`
`—_ or oO
`
`0
`
`1
`
`2
`3
`4
`- Force at Dimple (gm)
`
`5
`
`6
`
`7
`
`FIG. 8
`
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`

`

`U.S. Patent
`
`Apr. 1, 1997
`
`5,617,274
`
`Sheet 5 of 8
`
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`

`

`U.S. Patent
`
`Apr. 1, 1997
`
`Sheet 6 of 8
`
`5,617,274
`
`
`
`1230
`
`1220
`
`1260
`4250 1232
`12,0—esOSFIG. 18
`
`15
`
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`

`U.S. Patent
`
`Apr. 1, 1997
`
`5,617,274 FormLine
`
`Sheet 7 of 8
`
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`

`5,617,274
`
`Apr. 1, 1997
`
`Sheet 8 of 8
`
`U.S. Patent
`
`
`
`1532
`
`1610
`
`1520
`
`"600
`
`1502
`
`1504
`
`A506
`
`152
`
`FIG. 16
`
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`

`

`5,617,274
`
`5
`
`1
`LOW PROFILE INTEGRAL FLEXURE FOR
`CLOSELY PACKEDDISKSIN A DISK DRIVE
`ASSEMBLY
`
`2
`cxample U.S. Pat. No. 5,377,064 disclosesa flexure in FIG.
`12 that has a bonding pad including an upwardly facing
`dimple formed therein. The dimple is designed to be pushed
`against a portion of the load beam, thereby preloading the
`transducer head. Two-piece load beams with a dimple can
`BACKGROUND OF THE INVENTION
`advantageously supply substantial preload because the
`dimple is very stiff. However, two-piece load beams have
`1. Field of the Invention
`disadvantages including increased cost of manufacturing.
`This invention relates generally to transducer suspension
`_—~Particularly, the two pieces each must be separately tracked
`systems for magnetic recording media, and more particu.
`larly to low-profile flexures that connect a transducer head jg 1 inventory control, additional tooling is required to handle
`with a load beam.
`cachPatt and each Part mustbe inspected. Furthermore,
`addition
`8 are necessary
`to manufacture a
`two-
`2. Description of the Related Art
`load beam andfiexure, and there is an increase in the number
`Direct access storage devices (DASDs) such as disk
`of rejected parts. Integral flexures can solve many of these
`drives store information on concentric tracks of a rotatable
`problems.
`magnetic recording disk. In order to read or record the 15
`Qpe example of an integral flexure is disclosed in U.S.
`desired information on a rotating disk, a magnetic head or
`Pat. No. 5,282,102 to Christianson, which shows two sepa-
`other transducer elementon a suspension arm is moved from
`rate bonding pads connected by a torsion bar. The transducer
`track to track by a rotary orlinear actuator, The suspension
`head is connected to both bonding pads. The bonding pad
`arm is part of a head suspension assembly that typically
`torsion bar is connected to a load beam torsion bar that
`includes a load beam attachedto an actuator arm,a flexible 20
`extends across an opening on thetip of the load beam. As
`member (known asa flexure) connected to the Joad beam,—_—_shown,for example in FIG. 7B ofU.S.Pat, No. 5,282,102,
`and a transducer head attached to the flexure. The magnetic
`the bonding pad andtorsion bar assembly stamped to allow
`heads, which actually read or write data on the disk, are
`clearance for pitching and rolling of the transducer head.
`positioned within an air-bearing slider. While the disk
`Integral flexures have advantages of simplicity and a low
`rotates, the slider “flies” slighily above the surface of the 25
`cost of manufacture because they can be formed by an
`rotating disk, the load beam supports the slider, and the
`etching processatlittle additional cost. One disadvantage is
`flexure allows it
`to gimbal
`io adjust
`its oriemation for
`that preloading the transducer head is usually accomplished
`unavoidable disk surface run outor flatness variations.
`by stamping (deforming the metal by pressure), a process
`Examples of suspension systems are shown in the fol-
`that is difficult to control precisely.
`lowing references: U.S. Pat. No. 5,377,064 to Yaginumaet 30
`One drawback of conventional integral flexures such as
`al.,
`issued Dec. 27, 1994; U.S. Pat. No. 5,282,102 to
`disclosed aboveis that, because the slider preload is deliv-
`Christianson, issued Jan. 25, 1994; U.S. Pat. No. 5,225,950
`ered by a thin partially etched feature acting in bending
`to Crane, issued Jul. 6, 1993; U.S. Pat. No. 5,198,945 io
`alone or in combination with in-plane forces, preload forces
`Blaeseretal., issued Mar. 30, 1993; U.S. Pat. No. 5,187,625 3s have been limited to small values. If preload were to be
`to Blaeser et al.,
`issued Feb. 16, 1993; U.S. Pat. No.
`increased in these conventional flexures, the flexure would
`5,115,363 to Khan et al., issued May 19, 1992; U.S. Pat. No.
`be either over-stressed or deflected beyond acceptable val-
`4,996,623 to Erpeldingetal., issued Feb. 26, 1991; U.S. Pat.
`ues, causing undesirable interference between the flexure
`No.4,797,763 to Levy etal., issued Jan. 10, 1989; U.S.Pat.
`and the slider. In a conventional integral! flexure,stiffness is
`No. 4,761,699 to Ainslie et al., issued Aug. 2, 1988. Euro- 4g directly related to its thickness, but stress relates to the
`pean Patent Application Publication No. 0487914A2 to“"square ofthickness and deflectionrelates to its to the cube.
`Footeet al., published Jun. 03, 1992; PCT Publication No.
`In general, this means that stress and, in particular, deficc-
`W094/24664 for Jurgenson, published Oct. 27, 1994; PCT
`tion, will often dominate the behavior of the flexure.
`Publication No. WO 94/16438 for Budde, published Jul. 21,
`Large capacity disk drives typically have multiple disks
`1994; PCT Publication No. WO 94/12974 for Budde, pub- 45 mounted on the same rotating spindle. The multiple disk
`ished Jun.9, 1994and Japanese Patent Publication No.
`configuration advantageously provides greater
`storage
`59-207065 for Hashimoto, published Nov. 24, 1984,
`within the fixed size constraints imposed by industry stan-
`A flexure mustprovide a proper pivotal connection for the
`dards such as the form factor package. Disk-to-disk spacing
`slider so that during operation,the slider can compensatefor
`in a range from 2.4 mm to 4.0 mm is near the limits of
`irregularities in manufacture and operation by pitching and/ 59 current technology and imposesa limit upon the number of
`or rolling slightly in order to maintain the air bearing while
`disks that can fit in a form factor package. In order to
`maintaining appropriate stiffness against yaw movement.
`accommodate even more disks within the same height, it
`Pitch is defined as rotation about an axis extending directly
`would be advantageous to reduce the disk-to-disk spacing
`out from the actuator arm in the plane of the disk, and roll
`even further.
`1s defined as rotation about an axis perpendicular to the pitch 55
`To provide closer disk-to-disk spacing it is important that
`axis butstill lying im the planeof the disk. Yaw 18 gyration
`a suspension system has a very low profile. In very small
`around an axis perpendicular to the air-bearing surface. In
`disk-to-disk spacing environments, the solid height of the
`order to be useful, any flexure must achieve low enough Ga (“Head Gimbal Assembly”) must be small enough to
`Pitch and roll stillness for the aur bearing flying height
`fit within the spacing between disks. The solid height of the
`tolerances while at the same time achieving high enough 4, 1A is defined as the distance from the slider’s air bearing
`yaw stifiness.
`surface to the most distant HGA feature abovetheslider. For
`Tn some suspension assemblies, the flexure is integral
`example, in a conventional two-piece suspension that has a
`with the load beam;i.e., it is formed from the same sheet of
`dimple to provide preload, the suspension profile includes
`metal. In other suspension assemblies, the flexure is manu-
`the flexure bond pad thickness, the dimple height, the load
`factured separately and then affixed to a load beam.
`65 beam thickness and the thickness of the load beam stiffen-
`Two-part load beams include a dimple to provide preload
`ers-or flanges-if they are oriented upwardly (away from the
`betweenthe flexure andthe main bodyofthe load beam. For
`slider). Of course, if the flanges are oriented downwardly,
`
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`

`5,617,274
`
`5
`
`4
`3
`then they do not contribute to the suspension profile. The
`FIG. 3 is a perspective view of a load beam having an
`integral
`flexure, also showing a transducer head to be
`solid height can be reduced by choosing the thinnest pos-
`sible slider and routing the signal wires on the suspension
`coupled thereto;
`side, instead of aboveit. Solid height can be reduced further
`FIG. 4 is a side perspective view ofthe load beam of FIG.
`3,illustrating the support flange formed thereon;
`by improving the profile of the suspension.
`FIG. 5 is a top plan view ofa preferred embodimentofan
`It would be an advantage to provide a load beam with an
`integral flexure;
`integral flexure that can provide substantial preload to allow
`FIG.6 is a cross-sectionof the center line of the integral
`pitching and rolling movements while substantially prevent-
`flexure of FIG. 5:
`ing yaw movement. It would be a further advantageif the
`integral flexure had a very low profile to be used in close 10 _ .
`.
`disk-to-disk spacing applications.
`FIG. 7 is a bottom plan view of the integral flexure of
`FIGS. 5 and 6, illustrating partially ctched areas;
`FIG.8 is a graphical depiction of the compressive contact
`at the dimple interface for two different radiuses of curvature
`SUMMARYOF THE INVENTION
`15 of a stainless steel dimple, and for a transducer head
`.
`oo.
`— .
`interfaces, one made of N58 and the other made ofsteel;
`In accordance with the objectives of this invention as
`FIG. 9is
`atop
`plan
`vi
`fan
`alternati
`bodiment
`of
`described above and to overcomethe limitations of the prior
`oe 718 a lop plan view Olan
`alternative embociment 0
`art, a suspension is provided that will fit between closely-
`an integral flexure;
`Le
`t
`°
`.
`:
`:
`:
`.
`.
`.
`.
`spaced disks in a disk drive system having multiple stacked
`FIG.10 is a cross-section view of the alternative embodi-
`disks, For example, 2 suspension assembly having the 59
`ment of FIG. 9;
`integral flexure described herein will fit within a 1.4 mm
`FIG. 11 is a bottom plan view ofthe alternative embodi-
`space between disks, with a merge clearance of 0.2 mm for
`ment of FIG,9, illustrating the partially etched regions;
`each suspension. Furthermore, a preload range up to six
`FIG.12 is still another embodimentof an integral flexure
`grams or more can be obtaincd. The low profile suspension
`in which a spacer and an etched dimple are utilized;
`described herein combinesthe high preload advantage of the 25
`FIG. 13 is a cross-section of the central
`line of the
`stamped dimple with the low cost advantage of the integral
`alternative embodimentof FIG. 12;
`flexure. The yaw stiffness and in-plane strength are also
`FIG. 14is a illustration of a load beam having an integral
`greatly improved.
`.
`flexure formed from a laminated load beam with integrated
`In order to provide these advantages, a load beam for a
`head suspension assembly in a disk drive system is provided. 30 wire leads;
`
`
`The load beam has an integral flexure for coupling to a FIG. 15 isatop plan vi f the alternati bodiment
`
`
`
`
`transducer head, and a main body for coupling to an actuatorthealternative embocimen29 18 4 lop Plan view O°
`
`
`arm, The main body of the load beam hasa first elongated
`of FIG. 14 including integrated leads in a laminated assem-
`member and a second elongated member. A pair of bending
`bly, and
`.
`.
`'
`.
`bars are provided in the integral flexure, including a first 35
`FIG.16 is a cross-section exploded viewof the laminated
`bending bar coupled to the first elongated member and a
`assembly of FIGS. 14 and 15, also showing a transducer
`second bending bar coupled to the second elongated mem-
`head.
`ber. The integral flexure includes a floating pad connected to
`DETAILED DESCRIPTION OF THE
`the pair of bending bars. A dimple is formedin said floating
`PREFERRED EMBODIMENT
`pad, extending in a downward direction. A torsion bar is 40
`.
`.
`oo.
`oe
`-.
`connected on its first side to the floating pad and onits
`This invention is described in a preferred embodimentin
`second side to a bonding pad. The bondingpad has a lower
`the.forewing arscription withreference to the Figures, in
`surface for connecting to a transducer head. Preferably, the
`which
`like numbers represent
`the sameor similar elements.
`rsion
`d the bending bars are formed
`havi
`i
`thickneseby.for example.partial ciching.Alsoaably 45 While this invention is described in terms of the best mode
`the bending bars have a U-shape. A transducer head is
`for achieving this invention’s objectives,it will be appreci-
`connected to the bonding pad, and is allowed to rest against
`ated by thoseskilled in the art that variations may be
`the dimple. In operation, the torsion bar twists to allow the
`accomplished in view of these teachings without deviating
`transducer head to roll, while the bending bars allow pitch-
`from the spirit or scope of the invention.
`
`ing motion. Yaw movementis minimized due to the result- 59 FIGS. 1 and 2 showaside andatop view,respectively, of
`ing high yaw stiffness of the structure.
`a disk drive system designated by the general reference
`The foregoing, together with other objects, features and
`number 110. The disk drive system 110 comprisesa plurality
`advantages of this invention, will become more apparen.
`Of‘Stacked magnetic recording disks 112 mounted to a
`whenreferring to the followingspecification, claims and the
`Spindle 114. The disks 112 may be conventional particulate
`accompanying drawings.
`55 of thin film recording disks or, in other embodiments, they
`may be recently proposed liquid bearing disks. The spindle
`14 is attached to a spindle motor 116 which rotates the
`spindle 114 and disks 112. A chassis 120 provides a housing
`for the disk drive system 110. The spindle motor 116 and an
`69 actuator shaft 130 are attached to the chassis 120. A hub
`assembly 132 rotates about
`the actuator shaft 130 and
`supports a plurality of actuator arms 134. The stack of
`—_agtuator arms 134 is sometimesreferred to as a “comb”. A
`rotary voice coil motor 140is attached to chassis 120 and to
`a rear portion of the actuator arms 134.
`A plurality of head suspension assemblics 150 are
`attached to the actuator arms 134. A plurality of transducer
`
`BRIEF DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`a _
`.
`For a more complete understanding of this invention,
`reference is now made to the following detailed description
`of the embodiments as illustrated in the accompanying
`drawing, whercin:
`FIG. 1 is a side view of a disk drive system and a ¢5
`controller unit in block form;
`FIG. 2 is a top view of a disk drive system;
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`5,617,274
`
`5
`6
`heads 152 are attached respectively to the suspension assem-
`transducer head 152. A torsion bar 334 connects the bonding
`blies 150. The heads 152 are located proximate to the disks
`pad 332 with a floating pad 336 that includes a downwardly-
`112 so that, during operation, they are in electromagnetic
`extending dimple 340. A pair of bending bars 350 and 352
`communication with the disks 112 for reading and writing.
`are formed betweenthe floating pad 336 and the main body
`of the load beam 150.Particularly,a first bending bar 350is
`The rotary voice coil motor 140rotates actuator arms 134 5
`connectedto thefirst- extended member 320onthe first side
`about the seae orderi Mere tne head
`of load beam 150, and a second bending bar 352 is con-
`suspension assembiles
`0
`the
`desired
`radial
`position on
`nected to the second extended member 322 on the second
`disks 112.The shaft 130, hub 132, arms 134, and motor 140
`side. The integral flexure 330 is described in more detail
`maybe referred to collectively as a rotary actuator assembly.
`subsequently with reference to FIGS. 5-7. Alternative
`A controller unit 160 provides overall control to system 19
`embodiments of the integral flexure 330 are described in
`110. Controller unit 160 typically includes (not shown) a
`subsequentfigures.
`central processing unit (CPU), a memory unit and other
`.
`.
`digital circuitry, although it should be apparent that these
`FIGS. 5, 6, and 7 show various views of the preferred
`aspects could also be enabled as hardware logic by one
`embodiment of the integral flexure330 shown in FIG,3.
`skilled in the computerarts. Controller unit 160 is connected
`to an actuator control/drive unit 166 which in tum is /° Particularly, FIG. 5 is a top plan view, FIG. 6 is a cross-
`connected to the rotary voice coil motor 140. This configu-
`section along the center of the integral flexure 330, and FIG.
`ration allowscontroller 160 to control rotation of the disks
`7 is a bottom plan view.
`112. A host system 180, typically a computer system, is
`In FIG.5, a transducer head 152 is shown in dotted lines
`connected to the controller unit 160. The host system 180
`where il is positioned on the integral fiexure 330. Particu-
`may send digital data to the controller 160 to be stored on 20
`larly, the transducer head 152 is bonded (o the bonding pad
`disks 112, or it may request that digital data at a specified
`332 on its lower surface by a suitable means, such as an
`location be read from the disks 112 and sent to the system
`adhesive. The transducer head 152 rests also on the bottom-
`180. The basic operation ofDASD units is well known in the
`most point ofthe dimple 340. The transducer headis allowed
`art and is described in moredetail in The Magnetic Record-
`19 roll and pitch as will be described. FIG. 5 shows the
`ing Handbook, C. Dennis Mee and Eric D. Daniel, McGraw- 25 orientationsfor the pitch, roll, and yaw axcs. Roll is defined
`Hill Book Company, 1990.
`b
`:
`.
`:
`.
`tae
`.
`y aroll axis 500 which extends approximately through the
`_ Reference is now made to FIG. 3 whichis a perspective
`conter line of the load beam and the center line of the
`view of a load beam 150 for onc embodiment. The load
`syansducer head. Asillustrated, the roll axis 500 is aligned
`beam comprises a generally flat planar structure that has
`with the torsion bar 334 which twists to allow rolling
`numerous features formed thereon by for example, etching. 30
`t. A pitch axis 502 is defined perpendicular to th
`Ononeend, the load beam 150 comprises a base section 300
`movement.
`Bie!
`eae OC
`perpencitcu.
`including an opening 304 for connection to the actuator arms
`‘Tl axis butstill in the middle planeof the flexure. A yaw
`134 (FIGS.1 and 2) by any suitable means. For cxample, a
`axis 504is defined extending directly out of the page. As can
`mounting plate (not shown) may be positioned opposite an
`be seen in FIG. 5, the roll axis 500 is approximately aligned
`actuator arm 134 andthe base section 300 in order to provide 4, with the torsion bar 334.
`a good support for connecting the load beam 150to the arm
`In operation, the transducer head 152 has freedom to
`134. The mounting plate is preferably made of a rigid
`move abcutthe roll axis 500 by rolling upon the dimple 340.
`material such asstainless steel, and attaches to the arm by a
`Furthermore, pitch movementis allowed alongthe pitch axis
`swage connection through opening 304 and into anopening—-$02. duetoflexing of thefirst and second bending arms 350
`in the arm 134 or an equivalent attachment. The support 4g
`and 352. The U-shaped bending arms 350 and 352 are
`plate and the load beam 150 maybeattached together by a
`“positioned approximately in the center of the transducer
`plurality of welds. The load beam 150 also includes a
`head. Advantageously, movement about the yaw axis 504 is
`plurality of holes 310, 312 and 314 formed into the load
`limited by the geometry of the design. Particularly, it is
`beam for purposesincluding tooling, positioning, and con-
`believed that the shape of the torsion bar 334 and the
`trolling the flexure location relative to the load beam.
`4s U-shape of the bending bars 352 operate together to sub-
`Flanges 316 and 318 are provided for stiffening the load
`Stantially restrict yaw movement.
`beam, one along each side of the length of the load beam.
`The U-shaped bending bars 350 and 352 comprise an
`Particularly, a first flange 316 is formed along a first side
`approximately straight section 510 extending from the fioat-
`extending from the base section 300, and a second flange
`—_—_ing pad 336,a curved section 512 definingthe bottom ofthe
`318 is formed extending along a second side from the basc so U-shape, and a secondstraight section 514 extending from
`section 300. FIG. 4 is a side perspective view of the load
`the U-shape’s bottom 512to thefirst elongated member 360.
`beam 150,illustrating the first flange 316. The flanges 316
`Anangle A is defined between the center line (conveniently
`and 318 may be conventionally manufactured by,
`for
`the roll axis 500) and a line 520 extendingparallel with the
`example, stamping.
`straight section 510 of the bending arm 350. In any given
`Thefirst side and the second side of the load beam 150 5, design, this angle A can be adjusted to optimize yaw and
`converge toward a tip that has a first elongated structural
`tangential stiffness. Of course, any adjustmentsto this angle
`member 320 on the first side, and a second elongated
`will also be made to the second bending bar 352,
`in
`member 322 on the second side. The extended members 320
`accordance with the symmetry of the design aboutthe center
`and 322 are connected to a flexure 330 that is integral in
`line.
`construction with the load beam 150. In other words, the ¢9
`The cross-section of FIG. 6 and the bottom plan view of
`flexure in the load beam is formedof a single sheet of metal
`FIG.7 illustrate several features formed bypartially etching
`utilizing an etching process. Preferably, the flexure’s fea-_selected areas so thatonly a portionoftheoriginal thickness
`tures, including the partially-etched features, are etched in
`remains. Particularly the torsion bar 334 includesa partially
`the same step with the other etched features on the load
`etched area 600 formed by partially etching along the
`beam.
`65 bottom side of the torsion bar 334. By controlling the
`With reference to FIG.3, the integral flexure'330 includes
`etching process and the area etched, the amount of flex
`a bonding pad 332 having a lower surface for coupling to the
`provided by the torsion bar 334 can be carefully controlled
`
`Nitto Ex. 1110
`Pkvvq!Gz/!2221
`IPR2018-00956
`KRT3129.11;67
`Rcig!23!qh!27
`Page 12 of 16
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`5,617,274
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`8
`7
`illustrated in FIGS.3 to 7, the bonding pad and floating pad
`within predetermined tolerances. Typically, the remaining
`are reversedin position. Particularly, the bonding pad 930 in
`partial thickness is about 50% of the original. Optionally, an
`FIG.9 is positioned on the leading edgeof the slider, which
`adhesion pocket 610 is formed by partial etching within the
`has an advantage in that less flying height variations occur
`area of the bonding pad 332 in order to provide a trap for
`during operation because the bonding pad is located at the
`excess adhesive and provide a good bonding between the 5
`leading edge wherethereis less air bearing pressure buildup,
`transducer head 152 and the bonding pad 332.
`and thus, less sensitivity of flying heightto distortions in the
`In the embodimentillustrated in FIGS. 5-7, the dimple
`air bearing surface (ABS).
`340 is formed by a stamping process in which the metal is
`With reference to FIGS. 9, 10 and 11, a floating pad 900
`deformed to the desired shape. The bonding pad 332 is
`stamped to provide a step 620 downward from the torsion 1 is coupled to the load beam extensions 360 and 362 via
`bar to the bonding pad, so that the bottom surface 630 ofthe
`bending bars. Particularly, a first bending bar 910 couples
`bonding pad is appropriately aligned approximately level
`the floating pad 900 with the first extended section 360 and
`with the bottommostpoint 632 of the dimple 340. The height
`a second bending bar 912 couples the floating pad 900 with
`of the stamped step 620 is typically 0.025 mm andthis is
`the second extended section 362. The floating pad 900
`cnough to provide about 2 degrees of pitch androll static 15
`includes a dimple 902 formed facing downwardly. A torsion
`altitude. In an alternative embodiment discussed with ref-
`bar 920 couplesthe floating pad 900 with a bonding pad 930.
`erence to FIGS. 12 and 13, as will be discussed further,
`In an assembled suspension arm, the transducer head 152 is
`stamping the bonding pad may be unnecessary.
`bondedto the bonding pad by any suitable adhesive or other
`With reference to FIG.7, the bending arms 350 and 352_means. The transducer head 152 rests on a downwardly
`include areas having partial thickness formed by partial 20
`facing tip 932 of the dimple 902. Thus, during operation, the
`etching. Particularly, an area 700 extending along the first
`transducer 150 is free to pitch and roll as necessary. Par-
`bending arm 350 and an area 702 including the second
`ticularly, the torsion bar 920 twists to allow the transduccr
`bending arm 352 each has a partial thickness. The partially
`head 150 to pivot about the dimple 902 to allow forrolling
`thick areas 700 and 702 can be formedby a partial etching
`movement. To allow pitching movement, the bending bars
`process performed simultaneously with partially etching the 25 910 and 912 allow the transducer head 150 to move accord-
`torsion bar area 600 and the adhesive pocket 610. All
`ingly. Yaw movement, which is undesirable, is minimized.
`partially etched regions have the samethickness.
`Referring now to FIG. 11, several partially-etched areas,
`FIG. 8 is a graph of calculated values illustrating the
`each of which has a partial thickness, are illustrated. Par-
`compressive contact stress at
`the interface between the 4,
`tially etched areas have a remaining thickness of about 50%
`dimple 340 and the transducer head 152. Particularly, the
`of the original. Particularly,thefirst and secondbending bars
`maximum compressive stress is graphed as a function of the
`910 and 912 are etched to a partial thickness in areas 1100
`forceat the dimple, Four separate curvesillustrate the effects
`and 1102,respectively, andthe torsion bar 920 is also etched
`of varying the radius of curvature of the dimple onthe stress
`to a partial thickness in area 1110 in order to reduce stiffness.
`level in the head and the dimple material. The dimple itself 35 A step 950 in the bonding pad 930 is formed preferably by
`is assumed to be madeofstainless steel and the head of an
`a stamping processin orderto align the bottom surfaceof the
`intermetalic, such as N58. A first graph line 800 shows the
`bonding pad 930 with the bottom portion 932 of the dimple.
`effect on the compressive stress for variations in the force
`The dimple 902 could be stamped simultaneously with the
`applied to the dimple, tier a dimple radius of 0.25 mm and
`formed step.
`a steel-to-N58 interface. Graph line 810 illustrates that same go
`FIGS. 12 and 13illustrate still another embodiment, in
`stress versus applied forth to the dimple for a radius of 0.25
`which a thin spacer sheet 1240 is positioned between the
`mm buta steel-to-steel interface. Similarly, a third graph line
`flexure and slider. Referring first to FIG. 12, a floating pad
`820 plots stress versus force for a value of R=0.5 and an
`1200 is affixed to the main body of the load beam bya pair
`N58-to-stcel interface, and a fourth graph line 840 graphs
`of bending bars. Particularly, a first U-shaped bending bar
`those same values, but with a steel-to-steel interface.
`4s 1210 is formed to connect the bonding pad 1200 with a first
`Even though a steel-to-N58 interface produces the most
`elongated member 360 from the load beam. A second
`stress for this design, this stress is still lower than conven-
`bending bar 1210 connects the bonding pad 1200 with the
`tional systems because the dimple force is only a fraction|second elongated member 362 of the main body ofthe load
`(about 20%)ofthe total preload and thus, the contact forces
`beam. A bonding pad 1220 is connected to a torsion bar
`between the transducer head and the dimple are relatively 5, 1230, which is connected to the floating pad 1200.
`small. The rest of the preload force is transmitted through the
`Referring both to FIG. 12 and FIG. 13, a spacer bar 1240
`bonding pad. Reducing the dimple force to about 20% ofthe
`having an approximately tangular shape is connected to the
`preload has further advantages because the stresses that
`bonding pad 1220 by conventional means such as adhesive
`cause pitting and failure are generally shear and tension
`or weld spots. The floating pad 1200 includes a dimple 1250,
`forces, rather than compressive forces. Particularly,
`the 55 partially etched on the bottom facing surface. Advanta-
`shear stresses are 33% andtensile stresses are 13% of the
`geously, partial etching avoids the stamping step and there-
`compressive stress shown in FIG.8. Fretting between the
`fore does not require stamping the dimple nor forming the
`transducer head and the dimpleis directly proportional to the
`bonding pad, bec