WO2023192083A1

WO2023192083A1 - Suspension assembly with baseplate having swaging tabs, and method of making same

Info

Publication number: WO2023192083A1
Application number: PCT/US2023/015977
Authority: WO
Inventors: Benjapa Tanampee; Kuen Chee Ee
Original assignee: Magnecomp Corporation
Priority date: 2022-03-30
Filing date: 2023-03-22
Publication date: 2023-10-05

Abstract

The present disclosure relates generally to suspension assemblies for supporting read/write heads adjacent rotating disks in disk drives and more particularly, to a baseplate with an etched hub geometry. Examples of a baseplate of a suspension assembly are provided. The baseplate includes a hub region and a flange extending from the hub region. The hub region includes tab features defining a swage hole, each of the tab features are separated by a slot formed by selectively chemically etching a section of material from the baseplate.

Description

SUSPENSION ASSEMBLY WITH BASEPLATE HAVING SWAGING TABS, AND METHOD OF MAKING SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of, and priority to, U.S. Provisional Application No. 63/325,489 filed on March 30, 2022, which is hereby incorporated by reference in its entirety.

FIELD

[0002] The present disclosure relates generally to suspension assemblies for supporting read/write heads adjacent rotating disks in disk drives and more particularly, to a baseplate with an etched hub geometry.

BACKGROUND

[0003] Increasing storage capacity is a goal in the data storage industry. Data storage products such as magnetic disk drives and optical disk drives, store digital information on rotating disks using a read/write head mounted on suspension assemblies. The information is typically recorded in concentric, circumferential tracks about the near-center of the disk.

[0004] The hubs of suspension assemblies are inserted into an actuator arm boss hole extending from an actuator body. Typically, a swage ball is passed through the cylindrical hubs to force the peripheries of the hubs to expand (swage) into tight engagement with the inner peripheries of the actuator arm boss hole. Thus, an actuator arm may carry multiple suspension assemblies on opposite sides of the rotating disk to support read/write heads in opposing directions, one up and one down. [0005] Figs. 1 -2 illustrate a conventional baseplate of a suspension assembly. The baseplate 10 includes a flange 12 and a hub region 14. The hub region 14 includes a cylindrical hub 16 defining a swage hole 22. The cylindrical hub 16 includes an inner surface 18 and an outer surface 20. The cylindrical hub 16 extends from a planar upper surface 10a of the baseplate 10. [0006] The cylindrical hub 16 is configured to fit into an opening in an actuator arm (not shown) where the cylindrical hub 16 is swaged into the actuator arm opening to secure the baseplate 10 to the actuator arm. Swaging is performed by, for example, driving a ball through the swage hole 22 of cylindrical hub 16, which has an outer diameter larger than an inner diameter of the cylindrical hub defined by the inner surface 18. As a result, the ball tends to exert a deforming load on the cylindrical hub 16, where the cylindrical hub 16 deforms to press against the walls of the opening in the actuator arm as the ball passes through the swage hole 22. [0007] To hold a head gimbal assembly in place, the interface between the baseplate 10 and the actuator arm must develop a suitable minimum retention torque. The amount of retention torque in a swage connection is dictated by the frictional force between the swaged members, which in turn is based on the friction between the cylindrical hub 16 and the actuator arm, the residual stresses in the cylindrical hub 16 of the swage, and the elastic stress in the actuator arm. [0008] The frictional force developed between the outer surface 20 of the cylindrical hub 16 and an inner surface of the opening in the actuator arm is dependent on the force exerted perpendicular to the interface (the normal force) between the cylindrical hub 16 and the actuator arm and the coefficient of friction between the two surfaces.

[0009] Both the inner and outer surfaces 18, 20 and the profile of the cylindrical hub 16 may be formed by stamping or coining. There are some limitations to manufacturing the baseplate 10 through a stamping or coining process. For example, narrow or small features on the flange 12 or the cylindrical hub 16 are difficult to manufacture through a stamping process. As a result, the inner and outer surfaces 18, 20 are typically limited to straight, smooth surfaces.

[0010] As the need for increased data storage capacity in hard disk drives has grown and the size of the disk drive has decreased to fit in smaller electronics. Forming a strong connection between the actuator arms and the suspension assemblies has been made more difficult as the relative components have become smaller.

SUMMARY

[0011] Examples of a suspension assembly and baseplate, and methods of forming are provided. The baseplate includes a hub region and a flange extending from the hub region. The hub region includes tabs defining a swage hole, each of the tabs are separated by a slot formed by selectively chemically etching a section of material from the baseplate.

[0012] In one embodiment, a suspension assembly is provided comprising a baseplate having upper and lower surfaces; a swage hole formed in the baseplate extending between the upper and lower surfaces; and a plurality of tabs extending from an edge of the swage hole, wherein each of the tabs includes first and second raised portions separated by a groove, and wherein each of the tabs extends above the upper surface of the baseplate such that the first and second raised portions face away from the swage hole. In some embodiments, the baseplate includes a planar surface portion adjacent the tabs that is recessed relative to the upper surface of the baseplate. In some embodiments, each of the tabs have a plurality of grooves, and the first and second raised portions are three or more raised portions separated by the plurality of grooves. Optionally, the swage hole and tabs may be located in a proximal portion of the baseplate, and the baseplate may further include a hinge portion and a distal portion, wherein the hinge portion integrally connects the proximal portion to the distal portion. In some embodiments, the hinge portion may include a pair of beans each having a thickness that is less than a thickness of the proximal portion and a thickness of the distal portion, and wherein the pair of beams extend between the proximal portion and the distal portion. Optionally, each of the tabs may include a neck region of reduced thickness relative to the first and second raised portions.

[0013] In another embodiment a baseplate is provided, the baseplate having upper and lower surfaces, a swage hole formed in the baseplate extending between the upper and lower surfaces; and a plurality of tabs extending from an edge of the swage hole, wherein each of the tabs includes first and second raised portions separated by a groove, and wherein each of the tabs extends above the upper surface of the baseplate such that the first and second raised portions face away from the swage hole.

[0014] In yet another embodiment, a method of forming a suspension assembly is providing, comprising the steps of: providing a baseplate having upper and lower surfaces, forming a swage hole in the baseplate that extends between the upper and lower surfaces by subjecting the baseplate to chemical etching, forming a plurality of tabs extending from an edge of the swage hole by subjecting the baseplate to chemical etching, wherein each of the tabs includes first and second raised portions separated by a groove, and bending each of the tabs such that the tab extends above the upper surface of the baseplate, and the first and second raised portions face away from the swage hole. In some embodiments, each of the tabs include a neck region of reduced thickness relative to the first and second raised portions, and bending of the tabs includes bending of the tabs about the neck region. Forming of the plurality of tabs may be performed by chemical etching of the baseplate to form a slot between adjacent ones of the tabs. In other embodiments, the method further includes the step of forming a planar surface portion adjacent the tabs that is recessed relative to the upper surface of the baseplate by subjecting the baseplate to chemical etching. In some embodiments, before the bending step, the first and second raised portions are even with the upper surface.

[0015] Optionally, the baseplate may include a proximal portion, a hinge portion and a distal portion, wherein the swage hole and tabs are located in the proximal portion of the baseplate. In this instance the method further comprises forming an opening between the upper and lower surfaces in the hinge portion by subjecting the baseplate to chemical etching, and leaving a pair of beams of the baseplate extending between and integrally connecting the proximal portion and the distal portion. In some embodiments the pair of beams each have a thickness that is less than a thickness of the proximal portion and a thickness of the distal portion.

[0016] Other features and advantages of examples of the present disclosure will be apparent from the accompanying drawings and from the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Examples of the present disclosure are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

[0018] Figure 1 illustrates a baseplate of a conventional suspension assembly;

[0019] Figure 2 is a side cross sectional view of the conventional baseplate of Figure 1;

[0020] Figure 3 illustrates a baseplate of a suspension assembly, in accordance with an example of the disclosure;

[0021] Figure 4 illustrates a sectional view of the baseplate of Figure 3;

[0022] Figure 5 illustrates a sectional view of a baseplate hub region of the baseplate of Figure 4, after bending of the tabs; [0023] Figure 6 illustrates the baseplate hub region of the baseplate of Figure 3, after bending of the tabs;

[0024] Figure 7 illustrates a suspension assembly with the baseplate of Figure 3 swaged onto an actuator arm; and

[0025] Figure 8 illustrates a baseplate of a suspension assembly, in accordance with an alternative example of the disclosure.

DETAILED DESCRIPTION

[0026] Examples of a suspension assembly with a baseplate are provided. The baseplate includes a hub region and a flange extending from the hub region. The hub region includes tabs defining a swage hole, where each of the tabs are separated by a slot formed by selectively chemically etching a section of material from the baseplate.

[0027] The baseplate structure is formed by subjecting the baseplate to chemically etching as further disclosed below, where the disclosed chemically etching process should be understood to be defined by the process steps by which the baseplate is made. By chemically etching the components herein, the manufacturing process imparts distinctive structural characteristics to the final baseplate.

[0028] A head gimbal assembly of a magnetic disk drive may be mounted to an actuator arm by swaging the baseplate to the actuator arm. The baseplate holds the head/gimbal assembly in place and restricts relative movement during operation of the disk drive. Both the baseplate and the actuator arm are constructed of metal materials. For example, a stainless-steel baseplate may be swaged to an extruded aluminum actuator arm.

[0029] Figs. 3-4 illustrate a portion of a suspension assembly 28 that includes a baseplate 30 in accordance with an example of the disclosure. The baseplate 30 includes a flange 32 and a hub region 34. The hub region 34 includes a plurality of tabs 36 that define a swage hole 38 (i.e., extend from the edge of the swage hole 38), where the swage hole 38 extends through the baseplate 30 between upper and lower surfaces 30a, 30b of the baseplate 30. In some examples, the tabs 36 are separated by slots 40 defined by removed sections of material, fabricated by a chemical etching process.

[0030] The baseplate 30 illustrates eight (8) tabs 36, but any number of tabs 36 may be formed. The slots 40 can be narrow (less area) to account for a greater number of tabs 36 in the hub region 34, or wide to account for fewer tabs 36. The slots 40 may be configured to accommodate tabs 36 with more or less surface area.

[0031] Each of the tabs 36 includes a first groove 42 (FIG. 4) formed into its upper surface by partially chemically etching the upper surface of the tab 36. Therefore, the tabs 36 may be formed by chemically etching (i.e., chemically etching is used to remove material completely through the baseplate 30 to form swage hole 38 and slits 40, leaving tabs 36 remaining) and the first grooves 42 may also be formed by chemically etching (i.e., chemically etching is used to partially remove material from the upper surface of the tabs 36).

[0032] Fig. 4 is a sectional view of the baseplate 30 of Fig. 3. The hub region 34 may include a planar surface portion 44 adjacent the tabs 36 that is recessed relative to the upper surface 30a of baseplate 30. The planar surface portion 44 may extend around the hub region 34 and onto each of the tabs 36. Each of the tabs 36 may include first raised portion 46 and a second raised portion 48, with first groove 42 separating the first and second raised portions 46, 48. The second raised portion 48 is positioned at a distal end of tab 36, while first raised portion 46 is positioned closer to a base portion of the tab 36. [0033] Tn an example of the disclosure, the first and second raised portions 46 and 48 can have an upper surface in a plane even with the plane of the upper surface 30a of baseplate 30. The bottom of first groove 42 and planar surface portion 44 are recessed below the plane of the upper surface 30a of the baseplate 30. The amount of recess of first groove 42 and planar surface portion 44 (relative to the upper surface 30a of baseplate 30) can be the equal or unequal to each other. For example, as shown in Fig. 4, the planar surface portion 44 is recessed further below upper surface 30a than is the bottom of first groove 42. In the present example, all of the following features can be formed by chemically etching material from select locations of the baseplate 30: swage hole 38 and slots 40 (chemically etching entirely through baseplate 30 leaving behind tabs 36), planar surface portion 44 and first groove 42 (chemically etching only partially into the upper surface 30a of baseplate 30 leaving behind first and second raised portions 46, 48 separated by first groove 42).

[0034] The lower surface 30b of baseplate 30 can be etched to form a second groove 50 proximate to a base of tabs 36 (on the opposite side of tabs 36 as planar surface portion 44). Second grooves 50 serve to provide a neck region of reduced thickness relative to the first and second raised portions for tabs 36 about which the tabs 36 will bend during the suspension assembly process as explained further below.

[0035] The baseplate 30 may be manufactured from planar stainless-steel sheets that are subsequently chemically etched to form the structure shown in Figs. 3-4. Additional features such as holes, slots, beams and hinges can be formed by chemically etching as needed.

[0036] Figs. 5 and 6 are sectional and perspective views, respectively, of a hub region 34 of the baseplate 30 of Fig. 4 and Fig. 3. As shown in Figs. 5 and 6, each of the tabs 36 may be bent out of plane (i.e., bent about the portion of tabs 36 that include the neck region of reduced thickness due to second grooves 50) so that tabs 36 can be swaged in the actuator arm boss hole (not shown). In their bent position, the tabs 36 provide for the first and second raised portions 46/48, and first groove 42 disposed there between, facing outwardly (for engaging with the surface of the actuator arm boss hole during swaging). Tabs 36 remain separated from each other by slots 40.

[0037] In their bent position, the tabs 36 provide first and second raised portions 46/48 separated by first groove 42 that face away from swage hole 38, for providing a compression area for a swaging process. The tabs 36 also provide an inner surface 52 that faces toward swage hole 38. Inner surface 52 corresponds to thickened portions of tabs 36 that includes first and second raised portions 46, 48 for supporting the swaging process, which includes inserting the tabs 36 into the boss hole of the actuator arm, and passing a swaging ball through swage hole 38, which presses on inner surface 52 to drive the first and second raised portions 46, 48 outwardly to engaged with the edge of the actuator arm boss hole.

[0038] Fig. 7 illustrates suspension assembly 28 that includes the above described baseplate 30 swaged to an actuator arm 74. The suspension assembly 28 includes a slider 62. The slider 62 may include a recording head (not shown) with a read/write element. The suspension assembly 28 may be semi-rigid, and include a stainless steel load beam 64 having a bend radius hinge 66 attached to base plate 30, stiffening rails 68, and an alignment slot 70. Tabs 36 are swaged into the boss hole 72 of actuator arm 74, such that the first and second raised portions 46, 48 of the tabs 36 are engaged with an edge of the boss hole 72 to secure the baseplate 30 to the actuator arm 74.

[0039] There are several advantages of the suspension assembly 28 and its formation. The first and second raised portions, separated by first groove 42, provides for a superior swaged connection with the edge of the boss hole of the actuator arm, because even if the first and second raised portions are slightly deformed during swaging, they still provide a non-uniform surface that will provide a higher coefficient of friction with the edge of the boss hole and help provide more compression area for the swaging process. Further, forming all the above described features by chemically etching material from baseplate 30 provides better control of the formation of such features, and simplifies manufacturing in a repeatable manner. Using an etching process also provides the advantage of allowing smaller features to be constructed, such as narrower widths or allowing for partial etching of the flange to create different levels of thickness not capable of being done by conventional stamping/coining processes.

[0040] Fig. 8 illustrates an alternative example where the baseplate 30 can be further etched to include a hinge portion and a load beam portion (i.e., so that the hinge and load beam are integrally formed as part of the baseplate 30). Specifically, a central portion of baseplate 30 is etched to create an opening 80 extending through the thickness of the baseplate 30 (i.e., between the upper and lower surfaces 30a, 30b) and positioned between a pair of beams 82. The pair of beams 82 serve as a hinge that integrally connects a distal portion 84 of baseplate 30 to a proximal portion 86 of baseplate 30 that includes the swage hole 38 and tabs 36. The pair of beams 82 have a thickness that is less than that of the proximal portion 86 and the distal portion 84 of the baseplate 30. Distal portion 84 serves as the load beam for the suspension assembly 28. With this example, the proximal portion 86 that includes the swage hole 38 and tabs 36, the beams 82 that serve as a hinge, and the distal portion that serves as a load beam, can be fabricated from a single continuous material through chemically etching.

[0041] It will be understood that terms such as “upper” and “lower” as used herein are terms of convenience that denote the spatial relationships of parts relative to each other rather than to any specific spatial or gravitational orientation. Thus, the terms are intended to encompass an assembly of component parts regardless of whether the assembly is oriented in the particular orientation shown in the drawings and described in the specification, upside down from that orientation, or any other rotational variation.

[0042] It will be appreciated that the term “present disclosure” as used herein should not be construed to mean that only a single disclosure having a single essential element or group of elements is presented. Similarly, it will also be appreciated that the term "present disclosure" encompasses a number of separate innovations, which can each be considered separate disclosures. Although the present disclosure has been described in detail with regards to the preferred examples and drawings thereof, it should be apparent to those skilled in the art that various adaptations and modifications of examples of the present disclosure may be accomplished without departing from the spirit and the scope of the disclosure. For example, while each tab 36 is shown with a single first groove 42, one first raised portion 46 and one second raised portion, each tab 36 can include a plurality of the first grooves, and therefore at least three raised portions plurality of first raised portions 46 and/or a plurality of second raised portions 48.

Claims

CLAIMS We Claim:

1. A suspension assembly comprising: a baseplate having upper and lower surfaces; a swage hole formed in the baseplate extending between the upper and lower surfaces; and a plurality of tabs extending from an edge of the swage hole, wherein each of the tabs includes first and second raised portions separated by a groove, and wherein each of the tabs extends above the upper surface of the baseplate such that the first and second raised portions face away from the swage hole.

2. The suspension assembly of claim 1, wherein the baseplate includes a planar surface portion adjacent the tabs that is recessed relative to the upper surface of the baseplate.

3. The suspension assembly of claim 1, wherein for each of the tabs: the groove is a plurality of grooves; and the first and second raised portions are three or more raised portions separated by the plurality of grooves.

4. The suspension assembly of claim 1 , wherein the swage hole and tabs are located in a proximal portion of the baseplate, and wherein the baseplate further comprises: a hinge portion and a distal portion, wherein the hinge portion integrally connects the proximal portion to the distal portion.

5. The suspension assembly of claim 4, wherein the hinge portion comprises: a pair of beams each having a thickness that is less than a thickness of the proximal portion and a thickness of the distal portion, and wherein the pair of beams extend between the proximal portion and the distal portion.

6. The suspension assembly of claim 1, wherein each of the tabs includes a neck region of reduced thickness relative to the first and second raised portions.

7. A method of forming a suspension assembly, comprising: providing a baseplate having upper and lower surfaces; forming a swage hole in the baseplate that extends between the upper and lower surfaces by subjecting the baseplate to chemical etching; forming a plurality of tabs extending from an edge of the swage hole by subjecting the baseplate to chemical etching, wherein each of the tabs includes first and second raised portions separated by a groove; and bending each of the tabs such that the tab extends above the upper surface of the baseplate, and the first and second raised portions face away from the swage hole.

8. The method of claim 7, wherein each of the tabs includes a neck region of reduced thickness relative to the first and second raised portions, and wherein the bending of the tabs includes bending of the tabs about the neck region.

9. The method of claim 7, wherein the forming of the plurality of tabs includes forming a slot between adjacent ones of the tabs by subjecting the baseplate to chemical etching.

10. The method of claim 7, further comprising: forming a planar surface portion adjacent the tabs that is recessed relative to the upper surface of the baseplate by subjecting the baseplate to chemical etching.

11. The method of claim 7, wherein for each of the tabs: the groove is a plurality of grooves; and the first and second raised portions are three or more raised portions separated by the plurality of grooves.

12. The method of claim 7, wherein the baseplate includes a proximal portion, a hinge portion and a distal portion, wherein the swage hole and tabs are located in the proximal portion of the baseplate, and wherein the method further comprises: forming an opening between the upper and lower surfaces in the hinge portion by subjecting the baseplate to chemical etching, leaving a pair of beams of the baseplate extending between and integrally connecting the proximal portion and the distal portion.

13. The method of claim 12, wherein the pair of beams each have a thickness that is less than a thickness of the proximal portion and a thickness of the distal portion.

14. The method of claim 7, wherein before the bending, the first and second raised portions are even with the upper surface.

15. A baseplate having upper and lower surfaces; a swage hole formed in the baseplate extending between the upper and lower surfaces; and a plurality of tabs extending from an edge of the swage hole, wherein each of the tabs includes first and second raised portions separated by a groove, and wherein each of the tabs extends above the upper surface of the baseplate such that the first and second raised portions face away from the swage hole.

16. The baseplate of claim 15, wherein the baseplate includes a planar surface portion adjacent the tabs that is recessed relative to the upper surface of the baseplate.

17. The baseplate of claim 15, wherein for each of the plurality of tabs: the groove is a plurality of grooves; and the first and second raised portions are three or more raised portions separated by the plurality of grooves.

18. The baseplate of claim 15, wherein the swage hole and tabs are located in a proximal portion of the baseplate, and wherein the baseplate further comprises: a hinge portion and a distal portion, wherein the hinge portion integrally connects the proximal portion to the distal portion.

19. The baseplate of claim 18, wherein the hinge portion comprises: a pair of beams each having a thickness that is less than a thickness of the proximal portion and a thickness of the distal portion, and wherein the pair of beams extend between the proximal portion and the distal portion.

20. The baseplate of claim 15, wherein each of the tabs includes a neck region of reduced thickness relative to the first and second raised portions.