Suspension assembly having dimple features for engaging with actuator arms - Patents.com

Abstract

The suspension assembly includes a base plate having an upper surface and a lower surface opposite the upper surface, a load beam attached to the base plate, a cylindrical hub extending from the upper surface with an inner surface defining a crimp hole extending through the base plate, and a plurality of dimples projecting from the upper surface of the base plate, each of the dimples including a rounded surface projecting from the upper surface of the base plate and terminating in an apex, the apex of the dimples defining a contact surface for engaging the lower surface of an actuator arm crimped to the cylindrical hub.

Description

[Technical field]

[0001] The present disclosure relates generally to a suspension assembly for supporting a read / write head adjacent a rotating disk in a disk drive, and more particularly to a base plate having features for engaging an actuator arm. [Background technology]

[0002] Increasing storage capacity is a goal in the data storage industry. Data storage products, such as magnetic and optical disk drives, store digital information on rotating disks using read / write heads mounted on suspension assemblies. Information is typically recorded in concentric circumferential tracks around approximately the center of the disk.

[0003] The hub of the suspension assembly is inserted into an actuator arm boss hole that extends from the actuator body. Typically, a crimping ball passes through the cylindrical hub, expanding (crimping) the periphery of the hub into tight engagement with the inner periphery of the actuator arm boss hole. Thus, the actuator arm can carry multiple suspension assemblies on either side of a rotating disk to support read / write heads in opposite directions, one above and one below.

[0004] 1 and 2 show a conventional suspension assembly 2 including a load beam 4 terminating at a proximal end with a hinge 6 connected to a base plate 8. A slider 10 (including a read / write head) is attached to the distal end of the load beam 4. The base plate 10 includes a cylindrical hub 12 defining a crimping hole 14. The cylindrical hub 12 extends from a flat top surface 8a of the base plate 8. The cylindrical hub 12 is configured to fit into an opening 18 in an actuator arm 16. The base plate 8 can be secured to the actuator arm 16 by crimping the cylindrical hub 12 into the actuator arm opening 18. Crimping can be accomplished, for example, by driving a ball having an outer diameter larger than the inner diameter of the cylindrical hub 12 through the crimping hole 14 of the cylindrical hub 12. As a result, the ball is prone to exert a deformation load on the cylindrical hub 12. The cylindrical hub 12 deforms as the ball passes through the crimp hole 14 and is forced against the wall of the opening 18 in the actuator arm 16 .

[0005] The interface between the base plate 8 and the actuator arm 16 should be such that there is no relative movement between these two components. The quality of this interface is determined by the quality of the crimp between the cylindrical hub 12 and the opening 18 in the actuator arm 16. Other factors may affect the quality of this interface. For example, the flatness of the upper surface 8a of the base plate 8 is important (i.e., to ensure a consistent contact surface with the underside of the actuator arm 16). Summary of the Invention [Problem to be solved by the invention]

[0006] As the suspension assembly 2 becomes thinner to accommodate higher density drives, it can become more difficult to ensure flatness of the upper baseplate surface. For example, the baseplate 8 can flex such that its upper surface 8a is not perfectly flat, and therefore does not provide a suitable flat surface for engaging with the flat lower surface of the actuator arm. Asymmetric baseplate designs have also been developed, which make it even more difficult to provide a consistently flat upper baseplate surface for consistent contact with the lower surface of the actuator arm after staking.

[0007] As the need for increased data storage capacity of hard disk drives increases and the size of disk drives shrinks to fit into smaller electronic devices, the associated components become smaller, making it more difficult to form a strong and reliable connection between the actuator arm and the suspension assembly. [Means for solving the problem]

[0008] The aforementioned problems and needs are addressed by a suspension assembly including a base plate having an upper surface and a lower surface opposite the upper surface, a load beam attached to the base plate, a cylindrical hub extending from the upper surface with an inner surface defining a crimp hole extending through the base plate, and a plurality of dimples protruding from the upper surface of the base plate, each of the dimples including a rounded surface protruding from the upper surface of the base plate and terminating in an apex.

[0009] A suspension assembly is provided that includes a base plate having an upper surface and a lower surface opposite the upper surface; a load beam attached to the base plate and extending along the lower surface of the base plate, the load beam including a ridge feature extending above the upper surface of the base plate; a cylindrical hub extending from the upper surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate; and a dimple protruding from the upper surface of the base plate, the dimple including a rounded surface protruding from the upper surface of the base plate and terminating in an apex, the cylindrical hub being disposed between the dimple and the ridge feature.

[0010] A suspension assembly is provided that includes a base plate having an upper surface and a lower surface opposite the upper surface; a load beam attached to the base plate and extending along the lower surface of the base plate, the load beam including first and second U-shaped features including portions that wrap around an edge of the base plate and extend along the upper surface of the base plate; a cylindrical hub extending from the upper surface, the cylindrical hub having an inner surface that defines a crimp hole extending through the base plate; and a dimple protruding from the upper surface of the base plate, the dimple including a rounded surface that protrudes from the upper surface of the base plate and terminates at an apex, the cylindrical hub being disposed between the dimple and the U-shaped feature.

[0011] In some examples, the suspension assembly includes a base plate having an upper surface and a lower surface opposite the upper surface, a load beam having an upper surface and a lower surface opposite the upper surface, the upper surface of the load beam being attached to the lower surface of the base plate, a cylindrical hub extending from the upper surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate, and a plurality of dimples protruding from the upper surface of the load beam, each of the dimples including a rounded surface that protrudes from the upper surface of the load beam and terminates at an apex, the dimples extending beyond the upper surface of the base plate.

[0012] In some examples, the suspension assembly includes a base plate having an upper surface and a lower surface opposite the upper surface; a load beam attached to the base plate; a cylindrical hub extending from the upper surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate; a plurality of dimples protruding from the upper surface of the base plate, each of the dimples including a rounded surface that protrudes from the upper surface of the base plate and terminates at an apex; and an actuator arm having an opening and a plurality of through holes, the cylindrical hub extending into the opening such that an outer surface of the cylindrical hub is engaged with an inner surface of the opening, and apexes of the plurality of dimples are disposed within the through holes.

[0013] Other objects and features of the present disclosure will become apparent from a consideration of the specification, claims, and accompanying drawings. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a conventional suspension assembly. [Diagram 2] FIG. 1 is a perspective view of a conventional base plate. [Diagram 3] FIG. 1 is a perspective view of a suspension assembly according to an example of the present disclosure. [Figure 4] FIG. 2 is a side cross-sectional view of a base plate according to an example of the present disclosure. [Diagram 5] FIG. 13 is a cross-sectional side view of a base plate and an actuator arm according to an example of the present disclosure. [Figure 6] FIG. 2 is a perspective view of a base plate and a load beam according to an example of the present disclosure. [Figure 7] FIG. 2 is a cross-sectional side view of a base plate, a load beam, and an actuator arm according to an example of the present disclosure. [Figure 8] FIG. 2 is a perspective view of a base plate and a load beam according to an example of the present disclosure. [Figure 9]FIG. 2 is a cross-sectional side view of a base plate, a load beam, and an actuator arm according to an example of the present disclosure. [Figure 10] FIG. 2 is a perspective view of a base plate and a load beam according to an example of the present disclosure. [Figure 11] FIG. 2 is a perspective view of a base plate and a load beam according to an example of the present disclosure. [Figure 12] FIG. 2 illustrates a perspective view of a base plate, a load beam, and an actuator arm according to an example of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present disclosure is directed to an example of a base plate of a suspension assembly for engaging an actuator arm. As shown in Figures 3-5, the suspension assembly 20 includes a base plate 22, a load beam 24, and a slider 26. The load beam 24 terminates at a proximal end with a hinge 28 connected to the base plate 22. The slider 26, which includes a read / write head, is attached to a distal end of the load beam 26. The base plate 22 includes opposed upper and lower surfaces 22a, 22b, and a cylindrical hub extending upwardly from the upper surface 22a of the base plate 22. The cylindrical hub includes an outer surface 30a and an inner surface 30b defining a crimp hole 32 extending through the base plate 22.

[0016] As best shown in Figures 3 and 4, the base plate 22 includes three dimples 34 disposed about the cylindrical hub 12. The dimples 34 are punch-through, meaning that they are formed using a punch process that acts on both the upper surface 22a and the lower surface 22b of the base plate 22. The dimples 34 may be formed by striking the lower surface 22b of the base plate 22 with a dimple punch, deforming the base plate 22 to form the dimples 34. Each dimple 34 includes a convex surface 34a (rounded surface) having a rounded convex shape that protrudes from the upper surface 22a of the base plate 22 and terminates at an apex A (i.e., the single maximum protruding point of the rounded convex surface 34a relative to the upper surface 22a) and a concave surface 34b (rounded surface) having a rounded concave shape that is recessed into the lower surface 22b of the base plate 22. Thus, the upper surface 22a of the base plate 22 is generally flat except for the cylindrical hub 30 and the convex surfaces 34a of the dimples 34.

[0017] The apexes A of the rounded convex surfaces 34a of the three dimples 34 provide three points defining a contact surface above the top surface 22a of the base plate 22 for engaging an actuator arm that is crimped to the base plate 22. As best shown in FIG. 5, to crimp the base plate 22 to the actuator arm 36, the cylindrical hub 30 of the base plate 22 is inserted into the opening 38 of the actuator arm 36 until the bottom surface 36a of the actuator arm 36 contacts the apexes A of the three dimples 34. A crimping process is then performed to secure the base plate 22 to the actuator arm 36 in the position shown in FIG. 5. The three dimples 34 provide a reliable contact surface against the bottom surface 36a of the actuator arm 36 with the rounded surfaces (surface contact limited to the apexes A of the rounded convex surfaces 34a of the three dimples 34) which reduces the contact area of ​​the top surface 22a with the actuator arm. Thus, even if the base plate upper surface 22a is not sufficiently flat or deforms from a flat shape, the dimples 34 still provide a three-point contact that defines a contact surface for secure contact with the lower surface 36a of the actuator arm 36, thereby making the crimped and crimped interconnection between the base plate 22 and the actuator arm 36 more reliable. The dimples 34 provide consistent and reliable contact between the upper surface 22a of the base plate 22 and the lower surface 36a of the contact arm 36, even if the base plate 22 is not flat and even if the dimples 34 are not at the same height. The dimple structure is robust and highly repeatable. The height of the dimples can be tailored to suit a particular base plate thickness and material. To minimize the contact area between each dimple and the lower surface of the actuator arm, each dimple 34 preferably has a symmetrical circular shape that provides an apex A of small size. It should be noted that while three dimples 34 may be ideal in many applications, the number of dimples 34 may be more or less than three and still provide excellent contact between the base plate 22 and the actuator arm 36 for the crimping process and the resulting crimped connection.

[0018] 6 and 7 show an alternative where the load beam 24 extends below the base plate 22 beyond the hinge 28 and terminates in a ridge feature 40 that extends upward beyond the far end of the base plate 22. The apex of the ridge feature 40 is above the upper surface 22a of the base plate 22 such that the ridge feature 40 and the dimple 34 (located on the other side of the cylindrical hub 30) provide a contact surface for the lower surface 36a of the actuator arm 36. Having the ridge feature 40 on the load beam 24, which can be thinner than the base plate 22, allows for additional machining steps to be added to fine-tune the height of the ridge feature 40, if necessary, to further reduce tolerances. A mechanical or laser adjustment process may be utilized for fine-tuning.

[0019] 8 and 9 show another alternative in which the load beam 24 extends beyond the hinge 28 below the base plate 22 and terminates in first and second U-shaped features 42 that wrap around the far end of the base plate 22. The first and second U-shaped features 42 have portions that extend along the top surface 22a of the base plate 22, thereby providing a contact surface for the bottom surface 36a of the actuator arm 36 in combination with the dimple 34 (located on the other side of the cylindrical hub 30), as best shown in FIG. 9. Compared to the ridge feature 40 of FIGS. 6-7, having two U-shaped features 42 helps reduce the contact area with the contact arm 36 and can provide a more consistent contact.

[0020] 10 illustrates another alternative in which the load beam 24 extends below the base plate 22 beyond the hinge 28 and the dimple 34 is formed on the load beam 24 instead of the base plate 22. Specifically, the load beam 24 includes opposing upper and lower surfaces 24a, 24b such that the dimple 34 protrudes from the upper surface 24a of the load beam 24 in a manner similar to that described above with respect to the example in which the dimple 34 protrudes from the upper surface 22a of the base plate 22. The dimple 34 on the load beam 24 extends through an opening 44 in the base plate 22. The apex of the rounded convex surface 34a extends above the upper surface 22a of the base plate 22 to engage the lower surface 36a of the actuator arm 36 during the staking process. Because the load beam 24 is thinner than the base plate 22, the dimple forming operation may be easier and aid in tighter tolerance control.

[0021] Figure 11 shows another alternative configuration that is the same as that of Figure 10 except that two of the dimples 34 on the load beam 24 are positioned beyond the far end of the base plate 22. In this configuration, one of the dimples 34 extends through an opening 44 in the base plate 22 and the other two dimples 34 extend upward beyond the far end of the base plate 22. The smaller base plate 22 of Figure 11 may be advantageous in reducing the overall suspension mass.

[0022] 12 illustrates another alternative configuration similar to that of FIGS. 3-5 except that the actuator arm 36 includes a through hole 46 that is aligned with the dimple 34 such that the through hole 46 at least partially receives the dimple 34 (i.e., apex A of the dimple 34 is located within the through hole 46) when the cylindrical hub 30 is inserted into the opening 38 of the actuator arm 36. The through hole feature 46 can provide additional alignment functionality during the staking process.

[0023] It should be understood that the present disclosure is not limited to the examples described above and illustrated herein, but encompasses any and all variations that fall within the scope of any claim. For example, references herein to the invention, embodiments, or examples are not intended to limit the scope of any claim or claim term, but instead merely refer to one or more features that may be covered by one or more of the claims.

Claims

1. 1. A suspension assembly comprising: a base plate having an upper surface and a lower surface opposite the upper surface; a load beam attached to the base plate; a cylindrical hub extending from the top surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate; a plurality of dimples protruding from the top surface of the base plate, each of the dimples including a rounded surface protruding from the top surface of the base plate and terminating in an apex.

2. The assembly of claim 1 , wherein each of the dimples comprises a rounded surface recessed into the lower surface of the base plate.

3. The suspension assembly of claim 1 , wherein an apex of the dimple defines a contact surface above the upper surface of the base plate.

4. 2. The suspension assembly of claim 1, further comprising an actuator arm having an opening, the cylindrical hub extending into the opening such that an outer surface of the cylindrical hub engages an inner surface of the opening, the actuator arm having a lower surface that engages apexes of the plurality of dimples.

5. The suspension assembly of claim 1 , wherein the plurality of dimples includes at least three dimples.

6. 1. A suspension assembly comprising: a base plate having an upper surface and a lower surface opposite the upper surface; a load beam attached to the base plate and extending along the lower surface of the base plate, the load beam including a ridge feature extending above the upper surface of the base plate; a cylindrical hub extending from the top surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate; a dimple protruding from the top surface of the base plate, the dimple including a rounded surface protruding from the top surface of the base plate and terminating in an apex; The cylindrical hub is disposed between the dimple and the ridge feature.

7. The suspension assembly of claim 6 , wherein the dimple comprises a rounded surface recessed into the lower surface of the base plate.

8. The suspension assembly of claim 6 , wherein the dimple apex and the ridge feature define a contact surface above the upper surface of the base plate.

9. 7. The suspension assembly of claim 6, further comprising an actuator arm having an opening, the cylindrical hub extending into the opening such that an outer surface of the cylindrical hub engages an inner surface of the opening, the actuator arm including a lower surface that engages an apex of the dimple and the ridge feature.

10. 1. A suspension assembly comprising: a base plate having an upper surface and a lower surface opposite the upper surface; a load beam attached to the base plate and extending along the lower surface of the base plate, the load beam including first and second U-shaped features including a portion that wraps around an edge of the base plate and extends along the upper surface of the base plate; a cylindrical hub extending from the top surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate; a dimple protruding from the top surface of the base plate, the dimple including a rounded surface protruding from the top surface of the base plate and terminating at an apex; The cylindrical hub is disposed between the dimple and the U-shaped feature.

11. The suspension assembly of claim 10 , wherein the dimple comprises a rounded surface recessed into the lower surface of the base plate.

12. The suspension assembly of claim 10 , wherein an apex of the dimple and the portion of the U-shaped feature that extends along the top surface of the base plate define a contact surface above the top surface of the base plate.

13. 11. The suspension assembly of claim 10, further comprising an actuator arm having an opening, the cylindrical hub extending into the opening such that an outer surface of the cylindrical hub engages an inner surface of the opening, the actuator arm including a lower surface that engages the apex of the dimple and the portion of the U-shaped feature that extends along the upper surface of the base plate.

14. 1. A suspension assembly comprising: a base plate having an upper surface and a lower surface opposite the upper surface; a load beam having an upper surface and a lower surface opposite the upper surface, the upper surface of the load beam being attached to the lower surface of the base plate; a cylindrical hub extending from the top surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate; a plurality of dimples projecting from the top surface of the load beam, each of the dimples including a rounded surface projecting from the top surface of the load beam and terminating in an apex; The dimple extends beyond the top surface of the base plate.

15. The suspension assembly of claim 14 , wherein one of the dimples extends through an opening in the base plate.

16. The suspension assembly of claim 14 , wherein the plurality of dimples extend through a plurality of openings in the base plate.

17. The suspension assembly of claim 14 , wherein an apex of the dimple defines a contact surface above the upper surface of the base plate.

18. 15. The suspension assembly of claim 14, further comprising an actuator arm having an opening, the cylindrical hub extending into the opening such that an outer surface of the cylindrical hub engages an inner surface of the opening, the actuator arm having a lower surface that engages the apexes of the plurality of dimples.

19. 1. A suspension assembly comprising: a base plate having an upper surface and a lower surface opposite the upper surface; a load beam attached to the base plate; a cylindrical hub extending from the top surface, the cylindrical hub having an inner surface defining a crimp hole extending through the base plate; a plurality of dimples projecting from the top surface of the base plate, each of the dimples including a rounded surface projecting from the top surface of the base plate and terminating in an apex; 11. A suspension assembly comprising: an actuator arm having an opening and a plurality of through holes, the cylindrical hub extending into the opening such that an outer surface of the cylindrical hub engages an inner surface of the opening, and apexes of the plurality of dimples are disposed within the through holes.

20. 20. The suspension assembly of claim 19, wherein each of the dimples comprises a rounded surface recessed into the lower surface of the base plate.

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