USRE39478E1 - Magnetic head suspension assembly fabricated with integral load beam and flexure - Google Patents

Abstract

A magnetic head suspension assembly is fabricated with an integral piece which includes a load beam section, a flexure section, a rest mount section and a leaf spring section between the load beam and rear mount. A tongue extends from the load beam to the flexure and has a down-facing load dimple which contacts the non-air bearing surface of an attached air bearing slider. The flexure includes narrow thin legs adjacent to a cutout that delineates the load beam tongue. The head suspension is characterised by a high first bending mode frequency and low pitch and roll stiffness.

Description

ThisThe present application is a divisional application of application No.08/521,786 filed Aug.31,1995, which is a reissue of application No.08/042,906 filed Apr.5,1993, which issued as U.S. Pat. No.5,282,103 on Jan.25,1994, which is a continuation-in-part of application Ser. No. 07/938,516, filed Oct. 7, 1992, now abandoned. The present application is related to copending reissue application Nos.08/662,531 and08/662,885, both filed Jun.13,1996, and also to copending reissue application No.10/631,993 filed Jul.30,2003.

CROSS-REFERENCE TO COPENDING APPLICATION

Copending U.S. patent application Ser. No. 07/926,033 filed Aug.5, 1992, now U.S. Pat. No. 5,299,081 issued on Mar. 29, 1994, is directed to a head suspension assembly particularly useful with nanosliders, which are about 50% of the size of the standard full size air bearing sliders. The present application which is a continuation-in-part of copending application Ser. No. 07/958,516, now abandoned, discloses a modified and improved head suspension assembly especially useful with femtosliders, which we about 25% of the size of the standard full size sliders. The subject matter of the aforementioned copending applicationU.S. Pat. No.5,299,081is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to a magnetic head suspension assembly that accommodates air bearing femtosliders which are used in compact disk drives.

DESCRIPTION OF THE PRIOR ART

Presently known disk drives, such as used in laptop or notebook computers, include at least one rotatable magnetic disk, at least one magnetic head assembly for transducing data recorded on the disk, and a rotary head actuator for transporting the magnetic head to selected data tracks on the routing disk. The magnetic head assembly comprises a head suspension fabricated with a rigid load beam element and a gimbaling flexure. A typical head suspension includes a load beam element and a flexure which are fabricated as separate parts and are then joined during assembly of the head suspension. Special tooling to implement accurate alignment and assembly of the load beam and flexure is required. After joinder of the load beam element and flexure, an air bearing slider is mounted at the end of the flexure. The slider supports a thin film magnetic transducer which coasts with the magnetic disk for recording or reading data signals.

During operation of the disk drive, the rotating magnetic disk provides an aerodynamic lift force to the slider, while an opposing gram load force is applied to the slider through the flexure. The resultant of the two opposing forces determines the flying height of the slider and its transducer relative to the disk surface. In its operating flying mode, the slider gimbals about a load dimple protrusion, commonly known as a load dimple, formed in the flexure.

In known prior art head suspension and flexure designs, the load force transfer and gimbaling action are separate to provide high first bending frequency with low pitch and low stiffness. The flexure participates slightly in the load transfer with the load beam while primarily providing the low pitch and roll stiffness gimbaling action and providing high stiffness for lateral motion. These suspensions are characterized by weak pitch, roll and bending stiffness when the head is flying over the disk surface. For optimum functioning, however, the suspension structure should provide a high first bending mode resonant frequency so that the slider can follow variations in the topography of the routing disk surface while providing low pitch and roll stiffness.

Another objective in the design of compact disk drives which are used in laptop or notebook computers is to minimize the size and mass of the drive components. A reduction in Z-height (vertical height) of the suspension and slider assembly results in a corresponding reduction in the Z-height of the compact disk drive incorporating the assembly. A standard full size slider is about 0.160 inch long, 0.125 inch wide and 0.0345 inch high. Presently known disk drives employ nanosliders that measure approximately 0.080 inch long, 0.063 inch wide and 0.017 inch high, which size is about 50% of the size of a standard slider. The novel suspension and slider design disclosed herein is particularly useful for femtosliders, which measure about 0.040 inch long, 0.020-0.026 inch wide and 0.0110 inch in overall height, which size is about 25% of the size of a standard full size slider. It should be understood that the novel design may be used with other size sliders as well.

SUMMARY OF THE INVENTION

An object of this invention is to provide a head suspension and slider assembly having significantly reduced Z-height.

Another object of this invention is to provide a head suspension assembly characterized by low pitch and roll stiffness.

Another object is to provide a head suspension assembly characterized by low bending stiffness with decreased gram load tolerance effects.

Another object is to provide a head suspension assembly characterized by a relatively high first bending mode, first torsion mode, and first lateral mode resonant frequencies.

A further object is to provide a head suspension design that affords significant savings and advantages in manufacture and mass production.

According to this invention, a magnetic head suspension assembly is formed from an integral planar piece comprising a load beam section and flexure section. The load beam is configured preferably as a truncated conical section having flanges along its sides and an extending tongue at its narrow end. The side flanges are formed with U-shaped channels and provide rigidity and stiffness to the load beam section. The load beam tongue extends into the flexure section and is formed with a hemispherical load dimple which faces down to the non-air bearing surface of a head slider. A U-shaped cutout portion that is formed in the flexure section adjacent to the load beam tongue delineates the shape of the tongue. In one embodiment of the invention, the flexure section includes two narrow etched legs that extend from the load beam and are disposed adjacent to the cutout portion. The narrow legs are connected by a lateral ear at the end of the flexure. from the narrow end of the load beam section into a shaped opening of the flexure section. The load beam tongue is formed with a load supporting protrusion or dimple that extends downward to contact a non-air bearing surface of a head slider. The shaped opening defines two flexure beams that extend in a longitudinal direction of the load beam. The flexure beams are connected by a transverse section at the end of the flexure section opposite the narrow end of the load beam section.In this implementation, the head slider is bonded to the bottom surface of the lateral ear transverse section. In an alternative embodiment, the flexure section includes outriggers configured as a split tongue to which the slider is bonded.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail with reference to the drawings in which:

• • FIG. 1A is a top plan view of a head suspension and slider assembly, made in accordance with this invention;

FIG. 1B is a from elevational view of the head suspension ofFIG. 1;

FIG. 2 is a side elevation view of the assembly ofFIG. 1, showing a head slider attached to the end of the flexure, in a loaded position and in phantom in an unloaded position;

FIG. 3 is a bottom view of the head suspension ofFIG. 1;

FIG. 4 is a side elevation view of the assembly ofFIG. 3, showing the load dimple without an attached slider;

FIG. 5A is an enlarged view of a portion of the head suspension ofFIG. 3;

FIG. 5B is a front elevation view of the head suspension ofFIG. 5A;

FIG. 6A is an enlarged view of a portion of a head suspension and flexure incorporating an alternative design;

FIG. 6B is a front elevation view of the head suspension portion ofFIG. 6A;

FIG. 6C is a representational front view showing the overhang of the outriggers ofFIG. 6A relative to a slider,

FIG. 7 is a side elevation view of a portion of the head suspension shown inFIG. 6A;

FIG. 8 is a plan sectional representation of a paddle board or fret illustrating three of a multiplicity of head suspension bodies stamped from a piece of stainless steel;

FIG. 8A is a side elevation view of the paddle board ofFIG. 8;

FIG. 9 is a top plan view of a nanoslider suspension, such as disclosed in the aforementioned copending application;

FIG. 10 is a top plan view of a femtoslider suspension, with an extended part to enable handling during production;

FIG. 11 is a top plan view of the femtoslider suspension ofFIG. 10 with a skewed configuration relative to the extension;

FIG. 12 shows the femtoslider suspension without the extension for the purpose of illustrating the relative sizes or the nanoslider suspension and the femtoslider suspension;

FIG. 13 is a top plan view of a femtoslider suspension, partly broken away, including load/unload side tabs;

FIG. 13A is a section A—A taken throughFIG. 13;

FIG. 14A is a top view of the flexure of the suspension, partly broken away, showing a stepped flexure;

FIG. 14B is a side view of the flexure ofFIG. 14A;

FIG. 14C is a front view of the flexure of FIG.14A.

Similar numerals refer to similar elements in the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference toFIGS. 1A-5B, a magnetic head suspension assembly includes aload beam section10, aflexure section12, aleaf spring section56 and arear mount section42. The suspension is formed from an integral flat piece of nonmagnetic material, preferably a 300 Series type stainless steel having a thickness of about 0.0012 to 0.0013 inch. As a result of using an integral piece, theload beam section10 andflexure section12, as well as theleaf spring section56 andrear mount section42, are disposed substantially in a single plane. No separate forming of individual load beam and flexure parts is required. Therefore, no assembly steps of joining and welding are needed for attaching the flexure to the load beam.

Theload beam section10 is preferably made in a truncated conical or triangular shape. The load beam section has a shorttapered tongue14 extending from its relatively narrow end into theflexure section12. Thetongue14 is delineated by aU-shaped cutout16 in the flexure section. the relatively narrow end of the load beam section into a shapedopening16 offlexure section12. Thetongue14 delineates the U-shape of theopening16.Theload beam tongue14 provides low deflections in the direction orthogonal to the plane of the load beam section and flexure section by virtue of its short length and low gram load force.

A constrainedlayer damping element19 made ofelastomer10A about 0.002 inch thick and an overlay10B of about 0.002 inch thick stainless steel is laid down on the top surface of the major section of the load beam to minimize undesirable resonances of the suspension, as shown in FIG.1. Alternatively, a similar dampingelement21 may be deposited on the bottom surface of the load beam without interfering with theflexure12, as shown in FIG.3.

Theflexure section12 includesnarrow legs32 that are located adjacent to the sides of theU-shaped cutout16. Theflexure legs32flexure beams32 defined by shapedopening16. The flexure beams32 are chemically etched to a thickness of about 0.0010 inch for increased flexibility. The flexure beams32 are narrow,narrow legs32 are thin and relatively weak to allow the desired gimbaling action about the load dimple13 and also to allow the suspension to have low roll and pitch stillness. A lateral connecting part orear38transverse section38 is formed with the integral flat load beam and flexure to connect ends of thenarrow legs32. flexure beams32.

In this implementation of the invention, aslider22 is bonded to thelateral connecting part38. Ahemispherical load dimple18 is formed on theload beam tongue14 and is in contact with the top non-air bearing surface of anair bearing slider22 that is bonded to the lateral part orear38.transverse section38. Theload dimple18 is formed so that the hemisphere of the dimple faces down to the slider. Thedimple18 may be offset, 0-0.006 inch for example, from the centerline of the slider in order to control flying height characteristics.

U-shaped flanges24 extend along the sides of the load beam section and are truncated before reaching theflexure section12. Theflanges24 contribute to the stillness of the load beam section and localizes the bending action to thespring section56, thereby minimizing the pitch attitude changes due to arm/disk vertical tolerances.Head circuitry wiring92 without the conventional tubing is located within the channels of theflanges24. The absence of tubing allows the U-shaped channels of theflanges24 to be relatively shallow thereby contributing to the reduction of the Z-height of the head suspension assembly.Adhesive material90 is used to maintain thewiring92 fixed in place.Adhesive fillets91 are provided adjacent to theear38transverse section38 and theslider22. Thefillets91 are exposed and thus can be cured easily by application of ultraviolet radiation.

In a disk drive using this hand suspension and slider assembly, flexing occurs between theload beam tongue14 and theflexure legs32. With this design, the load force is transferred through thetongue14 to the truncated conical section of the load beam. This integral load beam/flexure configuration allows the separation of the applied load transfer force from the gimbal action so that the structure may be made stiff at the load beam for proper bending and relatively weak about the load dimple to allow proper pitch and roll of the slider.

A feature of the head suspension and slider assembly disclosed herein is that theslider22 is configured with astep28, which is formed by cutting a recessed portion orplatform30 on the non-air bearing top surface of theslider22. The Z-height of thestep28 is substantially the same as the Z-height of thehemispherical load dimple18. Sufficient spacing is provided between theload beam tongue14 and the top slider surface to allow free gimbaling action of theslider22 with no interference from the load beam. Theslider step28 is sufficiently high so that the slider end at the trailing edge can accommodate a thin film magnetic transducer including its coil turns.

Theleaf spring56 between theload beam section10 and therear mount section42 is formed with a trapezoidal-like cutout opening60 to provide flexibility. Theflexible section56 is formed to provide a desired load force that counteracts the aerodynamic lift force generated by the rotating disk during operation of the disk drive. The load force arises from bending the suspension from the phantom position, shown inFIG. 2, to the raised position as indicated by the arrow.

Therear mount section42 of theload beam10 bas ahole48 to allow connection of aswage plate46 to the suspension by means or aboss48 and by laser welding. Theswage plate46 provides stiffness to therear mount section42. Rear flanges54 provide wire routing channels to protect the wires during handling.

The head suspension and slider assembly described herein incorporates a stiff load beam and a relatively long and narrow flexure which includes thin weak flexure legs and connecting lateral part. With this design, low bending stiffness and high lateral and longitudinal stiffness with low roll and pitch stiffness are realized. The load beam tongue has a high vertical or perpendicular stiffness so that there is minimal bending of the load beam tongue up or down relative to the plane of the suspension. The first bending mode resonant frequency or vibration is substantially higher than known prior art suspension designs of comparable size.

In an actual implementation of this invention, the overall height of the slider is about 0.0110 inch, its length about 0.0400 inch, and its width about 0.020 inch. The height of thestep28 is about 0.0015 inch above the recessedportion30 which is 0.0336 inch long. The surface area or the top of thestep28 it preferably minimized in size to reduce the effects of bending or warping at the surface of the slider step which may occur due to the difference in the thermal coefficients of expansion of theceramic slider22 and thestainless steel ear38.transverse section38. Such bending would affect the flying characteristics of the head adversely.

In an alternative embodiment of the head suspension, illustrated in part inFIGS. 6A-7, theflexure section62 is formed with atongue64 and a cutout66. shaped opening66. A down-facingload dimple76 is provided on thetongue64. Narrowetched legs68 Narrow, thinly etched flexure beams68 that extend from theload beam10 are connected by atransverse part70. Thelegs68flexure beams68 are chemically etched to be thinner than the integral flat piece used to form the load beam and flexure sections.Outriggers72 forming a split tongue are provided at the sides of theflexure62 and are separated from thethin legs68 bycutouts74. flexure beams68 byspaces74. Theoutriggers72 overhang the sides of theslider22 and the slider is fastened to the outriggers by anadhesive fillet90. adhesive fillets61. In this implementation, the topnon-air bearing surface20 of theslider22 is bonded to theoutriggers72 by adhesive fillets which provide bond strength at thecutout16,61 which provide bond strength as shown in FIG.6C. Theslider22 is mounted to theoutriggers72 so that the center of the slider is aligned with theload dimple76, and the slider projects beyond the end of thetransverse part70. There is no offset of theload dimple76 relative to the centerline of the slider. With this implementation, a lower vertical height (Z-height) is realized. Also the slider bonding areas of theoutriggers72 are larger than the bonding area of thelateral connecting part38 offlexure12 of FIG.1. In this implementation, there is little room to move the slider toward the leading edge relative to the load dimple, which may be necessary to obtain optimal flying attitude. Also, additional forming is required in order to bend the twooutrigger legs72 down to thebend20, which increases the tolerance during production.

FIG. 8 shows a paddleboard or fret80 formed from a stainless steel piece that has been stamped with a number ofhead suspensions82, each of which was formed with the design shown in FIG.1. Tooling holes84 andsupport legs86 are provided for further handling.FIG. 8A shows the paddleboard80 withsupport legs86 bent to enable working on the extremely small femtoslider suspensions.

FIG. 9 shows a nanoslider suspension such as disclosed in copending application Ser. No. 07/926,033. The nanoslider includes aload beam94,flexure96,load beam tongue98,spring section100,rear mount section102 andslider104.

FIGS. 10 and 11 illustrate the femtoslider suspension of this invention with theload beam10,flexure12,spring section56 and a rear section having atooling hole106. Thetooling hole section106 is attached to anextension108 formed with anapertured swage110 that allows attachment to a rotary actuator. In effect for extremely small drives, such as 1.3 inch and smaller, theextension108 serves as an arm pivot and precludes the need for a separate arm structure, as used in the prior art. Theextension108 also allows the assembly to match the overall length of other industry standard “70%” microslider suspensions, thereby making it easy to use existing tooling.

FIG. 11 shows the suspension skewed with relation to theextension108 to compensate for skew experienced as the head moves between the outer diameter and the inner diameter of the disk during accessing. The extension may includeapertures112 for weight reduction, as shown in FIGS10 and11. Theapertures112 serve to adjust for resonant conditions and/or to adjust for total actuator balance about the pivot.

FIG. 12 illustrates the femtoslider suspension without the extension and shows the large difference size between the nanoslider and femtoslider suspensions. In an implementation of the femtoslider, the length was about 0.395 inch and the greatest width was about 0.056 inch.

With reference toFIGS. 13 and 13A, a head slider suspension includes flat side tabs120 which protrude to enable loading and unloading of the head suspension assembly relative to the surface of a magnetic disk in a disk drive. The side tabs may be present on one or both sides of the load beam. The side tabs120 are moved by means of a tool for lifting or lowering the suspension assembly. The addition of the flat side tabs which are in the same plane as the load beam does not add to the vertical Z-height of the suspension assembly.

FIGS. 14A-C depict a partial suspension assembly having a slider122 and a thin film transducer124 at a slider end. The slider222 has a flat top surface126 on which theload dimple76 is seated. The slider122 is not formed with astep78, as shown in the slider design of FIG.7. The flat surface124 extends across the entire top of the slider. However, the front end of the flexure128 is bent at section130 and132, as shown inFIG. 14B to allow the flexure to come down by a distance substantially equivalent to the height of theload dimple76. In this way, the flexure128 contacts the flat top surface126 of the slider122. The slider is bonded to the bent sections130 and132 by adhesive fillets134 and136. The flat contact surfaces of flexure128 and flat surface125 at the top of the slider are also bonded together by adhesive. By using a flat surface slider, the slider requires less machining, thus realizing a savings in time and labor costs as sell as a reduction in possible breakage and error during production.

By virtue of this invention, a single integral piece is formed with a load beam and flexure, thereby realizing a significant savings in material and labor. Alignment of the load beam and flexure and welding of the separate parts are eliminated. Certain critical tolerances that were required in former load beam/flexure assemblies are no longer needed thereby enhancing the assembly process. The design allows the separation of the load transfer function from the gimbaling action which eliminates the weak bending characteristic found with prior art suspensions. It should be understood that the parameters, dimensions and materials, among other things, may be modified within the scope of the invention. For example, the slider design with the step and platform configuration disclosed herein can be used with a “50” nanoslider suspension or other size suspensions.

Claims (35)

1. A magnetic head suspension assembly including an air bearing slider and at least one transducer disposed on said slider for transducing data that is recorded and read out from a surface of a rotating magnetic disk drive comprising:

a single integral planar piece of a specified thickness comprising,

a load beam section formed with a narrowed end;

a flexure section formed with two spaced narrow legs defining a cutout portion therebetween, said legs extending from said narrowed end of said load beam section, and a lateral ear spaced from said load beam section connecting said legs;

a tongue extending from said end of said narrowed load beam section, said tongue being disposed between said legs of said flexure section, said tongue having a free end within said flexure section, said tongue being formed with a load dimple;

said air bearing slider being bonded to said lateral ear and in contact with said load dimple;

whereby load transfer is effectively separated from the gimballing action of said slider so that pitch and roll stiffness is effectively reduced.

2. An assembly as inclaim 1, wherein said head slider has a top non-air bearing surface attached to said flexure section.

3. An assembly as inclaim 2, including means formed with said lateral ear for supporting said attached head slider.

4. An assembly as inclaim 3, wherein said supporting means comprises outriggers or a split tongue.

5. An assembly as inclaim 3, wherein said supporting means comprises said lateral ear that connects said narrow legs.

6. An assembly as inclaim 2, wherein said slider is about 0.0110 inch high, 0.0400 inch long and 0.0200-0.0260 inch wide.

7. An assembly as inclaim 2, wherein said top non-air bearing surface of said slider is formed with a platform and step adjacent to said platform.

8. An assembly as inclaim 7, wherein said platform of said slider is about 0.0336 inch long and said step is about 0.0015 inch high.

9. An assembly as inclaim 2, including a load dimple formed in said tongue.

10. An assembly as inclaim 9, wherein said load dimple is hemispherical in shape and faces down into contact with said top surface of said slider.

11. An assembly as inclaim 1, wherein said single integral planner piece including said tongue is about 0.0012 to 0.0015 inch thick and said narrow legs are about 0.0010 inch thick.

12. An assembly as inclaim 1, wherein said load beam section is shaped as a truncated triangle.

13. An assembly as inclaim 1, including a mount section at the rear end of said load beam section for enabling mounting said suspension to an actuator arm; and

a leaf spring section between said rear mount section and said load beam section for providing flexibility to said suspension.

14. An assembly as inclaim 13, including a swage plate joined to said mount section for providing rigidity to said rear end of said suspension assembly.

15. An assembly as inclaim 13, including front flanges formed along the edges of said load beam section and rear flanges formed along the edges of said rear mount section with a hiatus between said front and rear flanges.

16. An assembly as inclaim 15, wherein said front flanges are formed with shallow U-shaped channels, and electrical wiring without tubing is positioned within said channels.

17. An assembly as inclaim 13, including a cutout in said leaf spring section for providing flexibility to said suspension.

18. An assembly as inclaim 1, further including an apertured extension formed at the rear end of said suspension assembly for enabling attachment to an actuator of a disk drive without a separate head arm to enable pivoting of said suspension assembly.

19. An assembly as inclaim 1, including a damping material on said load beam.

20. An assembly as inclaim 1, including at least one load/unload tab formed at the sides of said load beam section.

21. An assembly as inclaim 2, wherein said top non-air bearing surface is substantially flat.

22. An assembly as inclaim 21, wherein said lateral ear includes bent sections for contacting with said top surface of said slider.

23. Apparatus for supporting a slider comprising:

a single piece of elongated material of a first thickness, the single piece of elongated material having a distal end and a proximate end:

a shaped opening in the single piece of elongated material adjacent the distal end; the shaped opening defining;

a transverse section disposed at the distal end of the single piece of elongated material, the transverse section having a slider mounting surface;

first and second flexure beams connected to the transverse section, the first and second flexure beams having a second thickness that is less than the first thickness;

a tongue that extends between the first and second flexure beams, the tongue including a load point protrusion that extends in a direction substantially normal to a bottom surface of the tongue.

24. The apparatus ofclaim 23, wherein the second thickness is approximately0.0010 inches.

25. The apparatus ofclaim 23, wherein the transverse section, the first and second flexure beams, and the tongue lie in the same general plane.

26. The apparatus ofclaim 23, wherein the load point protrusion is disposed along a centerline extending between the first and second flexure beams.

27. The apparatus ofclaim 23, wherein the load point protrusion is offset a distance from a centerline extending between the first and second flexure beams.

28. The apparatus ofclaim 27, wherein the distance is greater than zero inches, but less than or equal to0.006 inches.

29. Apparatus for supporting a slider comprising:

a single piece of elongated material of a first thickness, the single piece of elongated material having a distal end and a proximate end;

a shaped opening in the single piece of elongated material adjacent the distal end; the shaped opening defining:

a transverse section disposed at the distal end of the single piece of elongated material, the transverse section having a slider mounting surface;

first and second flexure beams connected to the transverse section;

a tongue that extends between the first and second flexure beams, the tongue including a load point protrusion that extends in a direction substantially normal to a bottom surface of the tongue; and

wherein the transverse section, the first and second flexure beams, and the tongue lie in the same general plane.

30. The apparatus ofclaim 29, wherein the first and second flexure beams have a second thickness that is less than the first thickness.

31. The apparatus ofclaim 30, wherein the second thickness is approximately0.0010 inches.

32. The apparatus ofclaim 29, wherein the load point protrusion is disposed along a centerline extending between the first and second flexure beams.

33. The apparatus ofclaim 29, wherein the load point protrusion is offset a distance from a centerline extending between the first and second flexure beams.

34. The apparatus ofclaim 33, wherein the distance is greater than zero inches, but less than or equal to0.006 inches.

35. The apparatus ofclaim 29, wherein the shaped opening is U-shaped.

Images