Base plate for disk drive suspension, disk drive suspension, and disk drive

Abstract

To provide a base plate of a suspension for a disk device, a suspension for a disk device, and a disk device capable of thinning an arm.SOLUTION: A base plate 20 is a base plate of a suspension 10 for a disk device connected to an arm provided in the disk device and includes a plate body 21 and a connection portion 40 provided on a plate body. The connection portion includes a through hole 41 passing through the plate body in a thickness direction of a plate body, a plurality of protrusions that are provided along an edge of the through hole in a circumferential direction around a central axis of the through hole and are inserted into a mounting hole of the arm, and an inner peripheral surface formed by the plurality of protrusions and the through hole, and the inner peripheral surface has a plurality of recesses 44 formed between the plurality of protrusions.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a base plate for a suspension for a disk drive, a suspension for a disk drive, and a disk drive. [Background technology]

[0002] Hard disk drives (HDDs) are used in information processing devices such as personal computers. Hard disk drives include a magnetic disk that rotates around a spindle and a carriage that rotates around a pivot shaft. The carriage has an arm that rotates around the pivot shaft in the track width direction of the disk using a positioning motor such as a voice coil motor.

[0003] A disk drive suspension (hereinafter simply referred to as the suspension) is attached to the arm. The suspension includes a base plate connected to the arm, a load beam, and a flexure arranged along the load beam. A slider that constitutes the magnetic head is provided on a gimbal portion formed near the tip of the flexure.

[0004] The slider is provided with an element (transducer) for accessing the disk, such as reading or writing data. The load beam, flexure, and slider constitute a head gimbal assembly.

[0005] Various proposals have been made regarding the connection between the base plate and the arm (for example, Patent Documents 1 to 5). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 2736174 [Patent Document 2] US Patent Application Publication No. 2021 / 0264941 [Patent Document 3] Japanese Patent Application Publication No. 02-049279 [Patent Document 4] U.S. Patent No. 5,187,626 [Patent Document 5] U.S. Patent No. 5,153,794 Summary of the Invention [Problem to be solved by the invention]

[0007] To accommodate the increasing recording density of disks, it is necessary to further miniaturize the head gimbal assembly and to position the slider with higher precision relative to the recording surface of the disk.

[0008] Due to the strong demand for increased recording capacity in hard disk drives in response to improved recording density, efforts are being made to increase the number of magnetic disks installed in hard disk drives (so-called multi-disk configurations). In order to increase the number of magnetic disks, it is necessary not only to make the magnetic disks thinner, but also to reduce the spacing between the magnetic disks.

[0009] To reduce the distance between magnetic disks, for example, the height of the boss on the base plate may be reduced, thereby reducing the thickness of the arm. However, reducing the height of the boss makes it difficult to maintain the connection between the base plate and the arm. There is still room for improvement regarding the connection between the base plate and the arm.

[0010] Therefore, one object of the present invention is to provide a base plate for a disk drive suspension, a disk drive suspension, and a disk drive that can reduce the thickness of the arm. [Means for solving the problem]

[0011] According to one embodiment, a base plate of a disk drive suspension is connected to an arm of a disk drive, and includes a plate body and a connection portion provided on the plate body. The connection portion has a through hole penetrating the plate body in a thickness direction of the plate body, a plurality of protrusions provided along the edge of the through hole in a circumferential direction centered on the central axis of the through hole and inserted into a mounting hole of the arm, and an inner circumferential surface formed by the plurality of protrusions and the through hole, and the inner circumferential surface has a plurality of recesses formed between the plurality of protrusions.

[0012] The plurality of protrusions may have a first length in the circumferential direction, and the plurality of recesses may have a second length in the circumferential direction that is longer than the first length. Each of the plurality of protrusions may have a root portion connected to the plate body, an extension portion including one end located opposite the root portion in the thickness direction, and a pressing portion located between the root portion and the one end and having a width in a radial direction intersecting the thickness direction that is greater than that of the root portion.

[0013] A disk drive suspension according to one embodiment includes a base plate of the disk drive suspension, a load beam connected to the base plate, and a flexure disposed along the load beam.

[0014] The base plate comprises a plate body and a connection portion provided on the plate body, and the connection portion has a through hole penetrating the plate body in the thickness direction of the plate body, and a plurality of protrusions provided along the edge of the through hole in a circumferential direction centered on the central axis of the through hole and inserted into mounting holes in the arm, and the plurality of protrusions do not have to overlap with a line that intersects the central axis and is parallel to the extension direction of the load beam.

[0015] A disk device according to one embodiment comprises an arm having a first mounting surface, a second mounting surface opposite the first mounting surface, and a mounting hole penetrating the first mounting surface and the second mounting surface, a first disk device suspension which is a disk device suspension connected to the arm from the first mounting surface side, and a second disk device suspension which is a disk device suspension connected to the arm from the second mounting surface side.

[0016] The first disk drive suspension has a first base plate, and the second disk drive suspension has a second base plate. The first base plate and the second disk drive suspension have a first protrusion and a second base plate, respectively. The first base plate and the second base plate are inserted into the mounting holes, and the first base plate and the second base plate overlap with recesses formed between the second base plate and the second base plate. The height of the first and second protrusions may be greater than the thickness of the arm. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a base plate for a disk drive suspension, a disk drive suspension, and a disk drive that can reduce the thickness of the arm. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic perspective view showing an example of a disk device. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a part of the disk device. [Figure 3] FIG. 3 is a schematic perspective view showing the suspension according to the first embodiment. [Figure 4] FIG. 4 is a schematic perspective view of a part of the tip end side of the suspension shown in FIG. 3, as viewed from the slider side. [Figure 5] FIG. 5 is a schematic plan view of the base plate shown in FIG. [Figure 6] FIG. 6 is a diagram for explaining a case where the base plates according to the first embodiment are stacked. [Figure 7] FIG. 7 is a schematic cross-sectional view of the base plate taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a schematic enlarged partial view showing part VIII in FIG. [Figure 9] FIG. 9 is a schematic partial cross-sectional view showing the suspension and the arm in FIG. [Figure 10] FIG. 10 is a schematic enlarged partial view showing the X portion in FIG. [Figure 11] FIG. 11 is a diagram showing a comparative example of the base plate according to the first embodiment. [Figure 12] FIG. 12 is a schematic partial cross-sectional view showing the suspension and arm shown in FIG. [Figure 13] FIG. 13 is a schematic enlarged partial view showing a portion XIII in FIG. [Figure 14] FIG. 14 is a schematic partial cross-sectional view showing a base plate and an arm according to the second embodiment. [Figure 15] FIG. 15 is a schematic partial cross-sectional view showing a base plate and an arm according to the third embodiment. [Figure 16] FIG. 16 is a schematic plan view showing a base plate according to the fourth embodiment. [Figure 17] FIG. 17 is a diagram for explaining a case where the base plates according to the fourth embodiment are stacked. [Figure 18] FIG. 18 is a schematic cross-sectional view showing a base plate according to the fifth embodiment. [Figure 19] FIG. 19 is a schematic plan view showing a base plate according to the sixth embodiment. [Figure 20] FIG. 20 is a schematic plan view showing a base plate according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] [First embodiment] Fig. 1 is a schematic perspective view showing an example of a disk drive (HDD) 1. In the example shown in Fig. 1, the disk drive 1 includes a case 2, a plurality of magnetic disks (hereinafter simply referred to as disks 4) that rotate around a spindle 3, a carriage 6 that can rotate around a pivot shaft 5, and a positioning motor (voice coil motor) 7 for driving the carriage 6. The case 2 is sealed with a lid (not shown).

[0020] 2 is a schematic cross-sectional view showing a part of the disk device 1. As shown in FIGS. 1 and 2, the carriage 6 is provided with a plurality of (for example, three) arms 8. The arms 8 may be called carriage arms, HSA arms, etc. The arms 8 are made of a metal material such as an aluminum alloy. The number of arms 8 provided on the carriage 6 is not limited to the above example.

[0021] A suspension 10 is attached to the tip of each of the arms 8. A slider 11 that constitutes a magnetic head is provided at the tip of each of the suspensions 10.

[0022] When the disk 4 rotates at high speed, air flows in between the disk 4 and the slider 11, forming an air bearing. When the positioning motor 7 rotates the carriage 6, the suspension 10 moves in the radial direction of the disk 4, causing the slider 11 to move to the desired track on the disk 4.

[0023] 2, the disk 4 includes a first disk 4A and a second disk 4B. The first disk 4A faces the second disk 4B at a predetermined distance. The disk device 1 includes a plurality of suspensions 10, which include a first suspension 10A and a second suspension 10B.

[0024] The first suspension 10A and the second suspension 10B are attached to one of the multiple arms 8 that is located at the center in the thickness direction of the case 2. The first suspension 10A and the second suspension 10B have a common basic configuration.

[0025] The first suspension 10A and the second suspension 10B are located between the first disc 4A and the second disc 4B. In the thickness direction of the case 2, the first suspension 10A faces the second suspension 10B. The number of discs 4 is not limited to two, but may be three or more. The number of suspensions 10 can be changed appropriately depending on the number of discs 4.

[0026] Fig. 3 is a schematic perspective view showing the suspension 10 according to the first embodiment. Fig. 4 is a schematic perspective view of a portion of the tip end of the suspension 10 shown in Fig. 3, as seen from the slider 11 side. The suspension 10 includes a base plate 20 connected to the arm 8 (shown in Fig. 2), a load beam 31, and a flexure 32.

[0027] The base plate 20, the load beam 31, and the flexure 32 all extend in the longitudinal direction of the suspension 10. Hereinafter, the longitudinal direction of the suspension 10, the base plate 20, the load beam 31, and the flexure 32 is defined as a longitudinal direction X.

[0028] The direction perpendicular to the longitudinal direction X is defined as the short-side direction Y of the suspension 10, base plate 20, load beam 31, and flexure 32. Since the suspension 10, base plate 20, load beam 31, and flexure 32 extend in the longitudinal direction X, the longitudinal direction X corresponds to the extension direction.

[0029] The direction intersecting (e.g., perpendicular to) the longitudinal direction X and the lateral direction Y is defined as the thickness direction Z of the suspension 10, base plate 20, load beam 31, flexure 32, etc. The thickness direction of the case 2 corresponds to the thickness direction Z. Furthermore, a sway direction S is defined as shown by the arc-shaped arrow near the tip of the load beam 31.

[0030] The base plate 20 is made of a metal material such as stainless steel. The thickness of the base plate 20 is, for example, 100 μm or less, for example, 50 μm. The thickness of the base plate 20 is greater than the thickness of the load beam 31 and the flexure 32, for example.

[0031] The base plate 20 includes a plate body 21 and a connection portion 40 provided on the plate body 21. The connection portion 40 has a through hole 41, a plurality of (for example, two) protrusions 42, and an inner peripheral surface 43. In the example shown in Fig. 3, the through hole 41 is formed, for example, at a position away from the tip (to the right in the figure) in the longitudinal direction X.

[0032] The load beam 31 is made of a metal material such as stainless steel. The thickness of the load beam 31 is, for example, 30 to 80 μm. The load beam 31 has a shape that tapers toward the tip.

[0033] The load beam 31 is connected to the base plate 20 by, for example, laser spot welding. The load beam 31 is elastically supported by the base plate 20. The flexure 32 is disposed along the base plate 20 and the load beam 31. The flexure 32 is fixed to the base plate 20 and the load beam 31 by, for example, laser spot welding.

[0034] The flexure 32 has a metal base 33 made of a thin stainless steel plate and a wiring portion 34 arranged along the metal base 33. The thickness of the metal base 33 is smaller than the thickness of the load beam 31.

[0035] The thickness of the metal base 33 is, for example, 12 to 25 μm, and in one example, 20 μm. A part of the wiring portion 34 is electrically connected to the elements of the slider 11 via a terminal for the slider 11.

[0036] 4, at the tip end portion 35, the flexure 32 further has a tongue 36 and a pair of outriggers 37. The slider 11 is mounted on the tongue 36. An element capable of converting magnetic signals and electric signals, such as an MR element, is provided at the tip end of the slider 11.

[0037] At the tip end portion 35, the wiring portion 34 is electrically connected to elements of the slider 11 via terminals. These elements are used to access the disk 4, such as to write or read data. The slider 11, load beam 31, and flexure 32 constitute a head gimbal assembly.

[0038] The pair of outriggers 37 are disposed on both sides of the tongue 36 in the short-side direction Y. The pair of outriggers 37 are shaped to protrude outward from both sides of the tongue 36 in the short-side direction Y. The tongue 36 and the pair of outriggers 37 are both part of the metal base 33, and their respective contours are formed by, for example, etching.

[0039] The tongue 36, the pair of outriggers 37, etc. form a gimbal portion 38. The gimbal portion 38 is formed on the tip portion 35 of the flexure 32. A microactuator element 39 is mounted on the gimbal portion 38. The microactuator element 39 has the function of rotating the tongue 36 in the sway direction S.

[0040] The microactuator elements 39 are arranged on both sides of the slider 11 in the short-side direction Y. The microactuator elements 39 are made of a piezoelectric material such as lead zirconate titanate (PZT). The microactuator elements 39 are each fixed to the actuator support portion of the tongue 36 with a conductive adhesive or the like.

[0041] Next, the base plate 20 will be described with reference to FIGS. Fig. 5 is a schematic plan view of the base plate 20 shown in Fig. 3. Fig. 6 is a view for explaining a case where the base plates 20 according to the first embodiment are stacked. Fig. 7 is a schematic cross-sectional view of the base plate 20 taken along line VII-VII in Fig. 5. Fig. 8 is a schematic partial enlarged view showing part VIII in Fig. 7. As described above, the base plate 20 includes the plate main body 21 and the connection part 40.

[0042] The plate body 21 is formed in a flat plate shape. For example, the length of the plate body 21 in the longitudinal direction X is longer than the length of the plate body 21 in the lateral direction Y. The plate body 21 has a first surface 22 and a second surface 23 opposite the first surface 22 in the thickness direction Z. For example, the first surface 22 is a surface facing the arm 8 to which the base plate 20 is connected.

[0043] The connecting portion 40 has a through hole 41, a plurality of protrusions 42, and an inner circumferential surface 43 formed by the through hole 41 and the plurality of protrusions 42. The inner circumferential surface 43 has a plurality of (for example, two) recesses 44. The connecting portion 40 is formed, for example, by coining using a die set.

[0044] The through hole 41 penetrates the first surface 22 and the second surface 23 in the thickness direction Z. In the example shown in Fig. 5, the through hole 41 is formed, for example, at approximately the center of the plate body 21 in the short-side direction Y. From another perspective, the center of the through hole 41 is positioned at an equal distance from a pair of edges of the plate body 21 aligned in the short-side direction Y.

[0045] 5 and subsequent figures, a line passing through the center of the through hole 41 is referred to as a central axis AX. The central axis AX extends in a direction parallel to the thickness direction Z. Here, a direction away from the central axis AX is defined as a radial direction R, and a circumferential direction θ is defined as a direction centered on the central axis AX. The radial direction R is a direction intersecting (e.g., perpendicular to) the thickness direction Z.

[0046] 5, a line that intersects with the central axis AX of the through hole 41 and is parallel to the longitudinal direction X is defined as a line LX, and a line that intersects with the central axis AX of the through hole 41 and is parallel to the lateral direction Y is defined as a line LY. In the example shown in FIG. 5, the line LX is located approximately at the center of the plate body 21 in the lateral direction Y.

[0047] The multiple protrusions 42 are inserted into mounting holes 83 (shown in FIG. 2) of the arm 8. The multiple protrusions 42 are provided along the edge 411 of the through-hole 41 in the circumferential direction θ. The multiple protrusions 42 are formed on the inner peripheral surface 43 in a discontinuous manner along the circumferential direction θ. The multiple protrusions 42 are point-symmetric with respect to the central axis line AX. Each of the multiple protrusions 42 has the same shape.

[0048] 5, the plurality of protrusions 42 protrude toward the central axis AX on the inner circumferential surface 43. The plurality of recesses 44 are respectively formed between the plurality of protrusions 42 in the circumferential direction θ. From another perspective, the plurality of recesses are portions of the inner circumferential surface 43 that are recessed outward in the radial direction R from the plurality of protrusions 42.

[0049] 5, the multiple protrusions 42 do not overlap with the line LX or the line LY. Each of the multiple protrusions 42 has a first length L1. Here, the first length L1 is the length of the protrusion 42 along the circumferential direction θ.

[0050] Each of the recesses 44 has a second length L2. Here, the second length L2 is the length of the recess 44 along the circumferential direction θ. The second length L2 corresponds to the distance between the protrusions 42 that face each other in the circumferential direction θ. In the example shown in FIG. 5, the second length L2 is longer than the first length L1.

[0051] From another perspective, the angle in the circumferential direction θ of the range in which the protrusions 42 are formed on the inner circumferential surface 43 is smaller than the angle obtained by dividing 360 degrees by twice the number of the protrusions 42. As an example, the angle in the circumferential direction θ of the range in which one protrusion 42 is formed is smaller than 90 degrees. The angles in the circumferential direction θ of the range in which each protrusion 42 is formed are, for example, equal to each other.

[0052] In Fig. 6, one base plate 20 is rotated 180 degrees about line LX and placed on the other base plate 20. In Fig. 6, the other base plate 20 is indicated by a dashed line. In this case, the first surface 22 of one base plate 20 faces the first surface 22 of the other base plate 20 in the thickness direction Z.

[0053] When a pair of base plates 20 are stacked as described above, the multiple protrusions 42 of one base plate 20 overlap with the multiple recesses 44 of the other base plate 20, and the multiple protrusions 42 of the other base plate 20 overlap with the multiple recesses 44 of one base plate 20. The multiple protrusions 42 of one base plate 20 do not overlap with the multiple protrusions 42 of the other base plate 20. The protrusions 42 of one base plate 20 and the protrusions 42 of the other base plate 20 are arranged alternately in the circumferential direction θ.

[0054] As shown in Figure 6, in the circumferential direction θ, a gap GP1 overlapping with the line LX and a gap GP2 overlapping with the line LY are formed between the protrusions 42 of one adjacent base plate 20 and the protrusions 42 of the other adjacent base plate 20.

[0055] 6, the length of the gap GP1 in the circumferential direction θ is approximately equal to the length of the gap GP2 in the circumferential direction θ. By arranging the multiple protrusions 42 as described above, the multiple recesses 44 of the other base plate 20 rotated 180 degrees about the line LX can be superimposed on the multiple protrusions 42 of one base plate 20.

[0056] Next, the protrusion 42 will be described. 7 and 8, the protrusion 42 protrudes from the second surface 23 toward the first surface 22 in the thickness direction Z. The protrusion 42 has a base portion 51 connected to the plate main body 21, and an extension portion 52 connected to the base portion 51 and extending further in the thickness direction Z than the plate main body 21.

[0057] As an example, the root portion 51 corresponds to the region between the first surface 22 and the second surface 23 in the thickness direction Z, and the extension portion 52 corresponds to the region other than the root portion 51. In the example shown in Figures 7 and 8, the extension portion 52 corresponds to the region extending upward in the figure beyond the first surface 22.

[0058] The protrusion 42 has an outer surface 53 located on the outer side in the radial direction R, an inner surface 54 located on the inner side in the radial direction R, and an end surface 55 connecting the inner surface 54 and the outer surface 53. The outer surface 53 is formed on the extension portion 52 and is connected to the first surface 22.

[0059] 7 and 8, the outer surface 53 extends parallel to the central axis AX. Here, "parallel" includes a case where the outer surface 53 is slightly inclined. The angle formed by the outer surface 53 and the first surface 22 is, for example, 90 degrees.

[0060] The end surface 55 is located on the opposite side to the base portion 51 in the thickness direction Z. The end surface 55 corresponds to one end of the extension portion 52. In the example shown in FIGS. 7 and 8, the end surface 55 is a surface that is approximately parallel to the radial direction R.

[0061] The inner surface 54 constitutes a part of the inner circumferential surface 43 of the connecting portion 40. The inner surface 54 is formed in the root portion 51 and the extending portion 52. The inner surface 54 includes a back hole surface 61, an inclined surface 62, a pressing surface 63, and an inclined surface 64. The back hole surface 61, the inclined surface 62, the pressing surface 63, and the inclined surface 64 are arranged in this order from the second surface 23 side in the thickness direction Z.

[0062] The back hole surface 61 is located in the root portion 51 and is connected to the second surface 23. The back hole surface 61 extends parallel to the central axis AX. The pressing surface 63 is located in the extension portion 52. The pressing surface 63 extends parallel to the central axis AX. The pressing surface 63 is parallel to the outer surface 53. As an example, the length of the pressing surface 63 in the thickness direction Z is greater than the length of the back hole surface 61 in the thickness direction Z.

[0063] 7 and 8, in the radial direction R, the pressing surface 63 is located closer to the central axis AX than the back hole surface 61, the inclined surface 62, and the inclined surface 64. From another perspective, the length from the central axis AX to the pressing surface 63 in the radial direction R is shorter than each of the lengths from the central axis AX to the back hole surface 61, the inclined surface 62, and the inclined surface 64 in the radial direction R. On the inner surface 54, the length from the central axis AX to the back hole surface 61 in the radial direction R is the longest.

[0064] The inclined surface 62 is formed from the base portion 51 to the extending portion 52, and connects the back hole surface 61 and the pressing surface 63. In the thickness direction Z, the inclined surface 62 is inclined from the back hole surface 61 toward the pressing surface 63 so as to approach the central axis AX.

[0065] The inclined surface 64 is located on the extension portion 52 and connects the pressing surface 63 and the end surface 55. In the thickness direction Z, the inclined surface 64 is inclined from the pressing surface 63 toward the end surface 55 so as to move away from the central axis AX. As an example, the length of the inclined surface 62 in the thickness direction Z is greater than the length of the inclined surface 64 in the thickness direction Z.

[0066] The protrusion 42 further has a pressing portion 56. In the thickness direction Z, the pressing portion 56 is located between the base portion 51 and the end face 55. In the radial direction R, the pressing portion 56 is located on the inner side of the protrusion 42 in the radial direction R.

[0067] The pressing portion 56 is, for example, a region of the extending portion 52 that includes the pressing surface 63. The protrusion 42 has the widest width at the pressing portion 56. The width is the length of the protrusion 42 along the radial direction R. Here, the width of the pressing portion 56 in the radial direction R is defined as width W1, and the width of the base portion 51 in the radial direction R is defined as width W2.

[0068] The width W1 in the radial direction R of the pressing portion 56 is, for example, the length from the pressing surface 63 to the outer surface 53 in the radial direction R. The width W2 in the radial direction R of the base portion 51 is the length in the radial direction R from the back hole surface 61 to the inner circumferential surface 43 that constitutes the recess 44. The width W1 in the radial direction R of the pressing portion 56 is greater than the width W2 in the radial direction R of the base portion 51.

[0069] Fig. 9 is a schematic partial cross-sectional view showing the suspension 10 and arm 8 in Fig. 2. Fig. 10 is a schematic partial enlarged view showing part X in Fig. 9. Figs. 9 and 10 show the arm 8 and a portion of the first suspension 10A and second suspension 10B connected to the arm 8. The load beam 31 is not shown in Fig. 10.

[0070] The arm 8 has a first mounting surface 81, a second mounting surface 82 opposite the first mounting surface 81, and a mounting hole 83 that penetrates the first mounting surface 81 and the second mounting surface 82 in the thickness direction Z. The mounting hole 83 is provided on the tip side of the arm 8. The mounting hole 83 has, for example, a circular shape in a plan view. The mounting hole 83 has an inner circumferential surface 84.

[0071] The first suspension 10A includes a base plate 20A, and the second suspension 10B includes a base plate 20B. The base plate 20A corresponds to the first base plate, and the base plate 20B corresponds to the second base plate.

[0072] The base plates 20A and 20B have the same shape as the above-described base plate 20. In Figures 9 and 10, as described with reference to Figure 6, the base plates 20A and 20B are connected to the arm 8 so that the first surfaces 22 face each other.

[0073] 9 and 10 , the first suspension 10A is connected to the arm 8 from the first mounting surface 81 side, and the second suspension 10B is connected to the arm 8 from the second mounting surface 82 side. The base plates 20A and 20B are each connected to the arm 8 via a mounting hole 83. In this case, the central axis AX of the through hole 41 coincides with the central axis AX of the mounting hole 83.

[0074] The first surface 22 of the base plate 20A contacts the first mounting surface 81, and the first surface 22 of the base plate 20B contacts the second mounting surface 82. The multiple protrusions 42 of the base plates 20A and 20B are inserted into the mounting holes 83. In the mounting holes 83, the protrusions 42 of the base plate 20A and the protrusions 42 of the base plate 20B are arranged alternately in the circumferential direction θ, as described with reference to FIG.

[0075] 9 and 10, in the thickness direction Z, the plurality of protrusions 42 of the base plate 20A overlap with the plurality of recesses 44 of the base plate 20B, and the plurality of recesses 44 of the base plate 20A overlap with the plurality of protrusions 42 of the base plate 20B. The outer surfaces 53 are in contact with the inner peripheral surface 84.

[0076] In FIG. 10, the thickness of the arm 8 is indicated by thickness T8, and the height of the protrusion 42 is indicated by height H4. Here, the height H4 of the protrusion 42 is the length from the first surface 22 to the end surface 55 along the thickness direction Z. The thickness T8 of the arm 8 is the length from the first mounting surface 81 to the second mounting surface 82 along the thickness direction Z. In the example shown in FIG. 10, the height H4 of the protrusion 42 is approximately equal to the thickness T8 of the arm 8. From another perspective, the end surface 55 is located on the same plane as the second mounting surface 82 in the thickness direction.

[0077] In the radial direction R, the pressing surface 63 overlaps with the inner circumferential surface 84. The pressing portion 56 is provided in the radial direction R such that the center of the pressing surface 63 in the thickness direction Z overlaps with the center of the inner circumferential surface 84 in the thickness direction Z.

[0078] 10, a line LC is shown as a line that is equidistant from the first mounting surface 81 and the second mounting surface 82 in the thickness direction Z and is parallel to the radial direction R. In the example shown in FIG. 10, the center of the pressing surface 63 in the thickness direction Z intersects with the line LC.

[0079] When connecting the base plate 20 to the arm 8, with the multiple protrusions 42 inserted into the mounting holes 83, the multiple protrusions 42 are pushed outward in the radial direction R as shown by the arrows in Figure 10, and the multiple protrusions 42 are plastically deformed outward in the radial direction R, thereby bringing the inner surface 84 and the outer surface 53 into tight contact with each other.

[0080] With multiple protrusions 42 inserted into the mounting hole 83, for example, by passing a ball through the mounting hole 83 of the arm 8 along the thickness direction Z, the multiple protrusions 42 can be pushed outward in the radial direction R via the pressing portion 56.

[0081] The ball is made of a metal material harder than the metal material that forms the base plate 20. The ball is made of, for example, stainless steel. The diameter of the ball is larger than the inner diameter of the inner circumferential surface formed by the pressing surface 63. Such a connection between parts is sometimes called a crimping process, a swaging process, or the like.

[0082] By passing the above-mentioned ball through the mounting hole 83 along the thickness direction Z, the multiple protrusions 42 are pushed outward in the radial direction R. This brings the outer surface 53 and the inner circumferential surface 84 into close contact with each other, and the base plate 20 is fixed to the arm 8. By forming the pressing portion 56 as described with reference to FIG. 10 , the force acting outward in the radial direction R when the ball passes through the pressing portion 56 is maximized.

[0083] The inclined surfaces 62, 64 connected to the pressing surface 63 function as guides for passing the ball toward the pressing surface 63. This reduces the resistance when passing the ball through the mounting hole 83, making it easier to pass the ball through the mounting hole 83 in the thickness direction Z. From another perspective, it is possible to reduce the load on the ball in the thickness direction Z when passing the ball through the mounting hole 83. This load is sometimes called a caulking force.

[0084] Fig. 11 is a diagram showing a comparative example of the base plate 20 according to the first embodiment. Fig. 12 is a schematic partial cross-sectional view showing the suspension 100 and the arm 80 shown in Fig. 11. Fig. 13 is a schematic partial enlarged view showing part XIII in Fig. 12.

[0085] As shown in Fig. 11, the suspension 100 includes a base plate 200. The connection portion 40 of the base plate 200 has a through hole 41 and a cylindrical boss 45. The boss 45 is provided along the edge of the through hole 41. The height of the boss 45 in the thickness direction is approximately equal to the height H4 of the protrusion.

[0086] 12 and 13, the first suspension 100A includes a base plate 200A, and the second suspension 100B includes a base plate 200B. The base plates 200A and 200B have the same shape as the base plate 200 described above.

[0087] In the example shown in FIGS. 12 and 13, the first suspension 100A is connected to the arm 80 from the first mounting surface 81 side, and the second suspension 100B is connected to the arm 80 from the second mounting surface 82 side.

[0088] The bosses 45 of the base plate 200A and the bosses 45 of the base plate 200B are inserted into the mounting holes 83. The outer surfaces 530 of the bosses 45 are in contact with the inner peripheral surface 84. The bosses 45 of the base plate 200A overlap with the bosses 45 of the base plate 200A in the thickness direction Z. A gap is formed between the bosses 45 of the base plate 200A and the bosses 45 of the base plate 200B in the thickness direction Z.

[0089] Therefore, in order to connect to the first suspension 100A and the second suspension 100B, the arm 80 needs to have a certain thickness. The thickness T80 of the arm 80 shown in Fig. 13 is greater than the thickness T8 of the arm 8 shown in Fig. 10. As an example, if the height of the boss 45 is approximately equal to the height H4 of the protrusion 42, the thickness T80 of the arm 80 needs to be at least twice the thickness T8 of the arm 8.

[0090] The boss 45 has a pressing portion 560 formed along the circumferential direction θ on the inner side in the radial direction R. The pressing portion 560 is provided with pressing surfaces 630. The pressing surfaces 630 are aligned in the thickness direction Z. In the radial direction R, the pressing surfaces 630 overlap with the inner circumferential surface 84.

[0091] As described above, gaps are formed between the bosses 45 in the thickness direction Z. As shown in Fig. 13 , from the perspective of the mounting hole 83, in the radial direction R, the center of the inner circumferential surface 84 in the thickness direction Z does not overlap with the pressing surface 630.

[0092] In the base plate 20 configured as described above, the connection portion 40 has a through hole 41, a plurality of protrusions 42, and a plurality of recesses 44 formed between the plurality of protrusions 42. When connecting a pair of base plates 20 to the arm 8, the plurality of protrusions 42 of one base plate 20 can be overlapped with the plurality of recesses 44 of the other base plate 20, and the plurality of protrusions 42 of the other base plate 20 can be overlapped with the plurality of recesses 44 of the one base plate 20.

[0093] From another perspective, the plurality of protrusions 42 of one base plate 20 do not overlap with the plurality of protrusions 42 of the other base plate 20. As a result, the thickness T8 of the arm 8 connecting the base plates 20 can be reduced, and the arm 8 can be made thinner.

[0094] With the suspension 10 including such a base plate 20, it is possible to reduce the thickness T8 of the arm 8. This allows the carriage 6 having the arm 8 to be made smaller. As a result, the thickness of the disk device 1 can be reduced, and the disk device 1 can be made thinner.

[0095] By reducing the thickness T8 of the arms 8, the distance between the discs 4 can be reduced, allowing the discs 4 to be mounted in the case 2. Furthermore, since more arms 8 can be mounted for a carriage 6 of the same height as before, more discs 4 can be mounted in the same case 2 as before.

[0096] Compared to the base plate 200 described using Figures 11 to 13, the base plate 20 allows the thickness T8 of the arm 8 to be reduced without making the height H4 of the protrusion 42 smaller than the height of the boss 45.

[0097] Although the thickness T8 of the arm 8 is reduced, the length of contact between the outer surface 53 and the inner peripheral surface 84 in the thickness direction Z remains the same as the length of contact between the boss 45 and the inner surface. Therefore, the base plate 20 can be reliably connected to the arm 8.

[0098] Because the multiple protrusions 42 are discontinuously formed in the circumferential direction θ, the multiple protrusions 42 can be easily pushed outward in the radial direction R. Compared to the base plate 200 described using Figures 11 to 13, with the base plate 20, there is no need to increase the load on the ball in the thickness direction Z when passing the ball through the mounting hole 83. This makes it easier to connect the base plate 20 and the arm 8.

[0099] By reducing the load on the ball in the thickness direction Z, it is possible to suppress the influence (for example, deformation) on the base plate 20 when connecting the base plate 20 to the arm 8. This makes it possible to suppress the influence of the base plate 20 on the characteristics of the suspension 10.

[0100] If a defect in the magnetic head is discovered during inspection after the disk drive 1 is assembled, the head gimbal assembly is reassembled to replace the defective head. In this case, it is necessary to remove the base plate from the arm.

[0101] For example, consider a case where a pair of base plates each having a boss are connected to an arm. In the mounting holes of the base plates, the outer surface of the boss of one base plate overlaps the inner surface of the boss of the other base plate in the radial direction R, and the bosses are plastically deformed outward in the radial direction R (interlock). If the base plates are connected to the arm by interlock, it will be difficult to remove the base plates from the arm, making it difficult to replace the head gimbal assembly.

[0102] Compared to when the base plate is connected to the arm by an interlock, in the case of base plate 20, the inner peripheral surface 84 is tightly attached to the outer surfaces 53 of the multiple protrusions 42 to connect the base plate 20 to the arm 8, so that base plate 20 can be easily removed from arm 8. Therefore, during inspection after the disk drive 1 is assembled, it is easy to replace only the head gimbal assembly that contains the defective head.

[0103] That is, with the base plate 20 of this embodiment, it is possible to provide a base plate 20, suspension 10, and disk device 1 that can reliably connect the base plate 20 and the arm 8 and that are easy to work with.

[0104] In the base plate 20, the recesses 44 have a second length L2 that is longer than the first length L1 of the protrusions 42. As described with reference to FIG. 6, when a pair of base plates 20 are stacked, gaps GP1 and GP2 are formed between adjacent protrusions 42, respectively.

[0105] Therefore, it becomes easier to overlap the plurality of protrusions 42 of one base plate 20 with the plurality of recesses 44 of the other base plate 20, and the pair of suspensions 10 can be easily connected to the arm 8.

[0106] By arranging multiple protrusions 42 as in this embodiment, multiple recesses 44 on one base plate 20 rotated 180 degrees around line LX can be superimposed on the multiple protrusions 42 on the other base plate 20.

[0107] This allows the base plates 20 of the suspensions 10 that face each other across the arm 8, such as the first suspension 10A and the second suspension 10B, to be the same.

[0108] 10 , the pressing portion 56 is provided in the radial direction R such that the center of the pressing surface 63 in the thickness direction Z overlaps with the center of the inner circumferential surface 84 in the thickness direction Z. This allows the outer surface 53 to press the inner circumferential surface 84 so as to include the center of the inner circumferential surface 84 in the thickness direction Z when the ball is passed through the mounting hole 83 along the thickness direction Z. As a result, the outer surface 53 can be stably brought into close contact with the inner circumferential surface 84, and the base plate 20 can be reliably connected to the arm 8.

[0109] As described above, by pressing the inner peripheral surface 84 from the outer surface 53 via the pressing portion 56, it is possible to suppress variations in the load on the arm 8 in the thickness direction Z. As a result, it is possible to suppress deformation of the arm 8 (for example, warping of the arm 8) that occurs when the base plate 20 is connected to the arm 8.

[0110] According to this embodiment, it is possible to provide the base plate 20, the suspension 10, and the disk device 1 that can reduce the thickness of the arm 8. In addition to the above, this embodiment also provides various other preferable effects.

[0111] Next, other embodiments will be described. In the other embodiments and modifications described below, components similar to those in the first embodiment described above will be given the same reference numerals as in the first embodiment, and detailed descriptions thereof may be omitted or simplified. The base plate 20 in each of the following embodiments can be applied to the suspension 10, and a disk drive 1 including the suspension 10 can be configured.

[0112] [Second embodiment] 14 is a schematic partial cross-sectional view showing the base plate 20 and arm 8 according to the second embodiment. As shown in FIG. 14, the extension portion 52 has a claw portion 57. The claw portion 57 is a region that protrudes beyond the mounting hole 83 when the protrusion 42 is inserted into the mounting hole 83. The end surface 55 is located at the claw portion 57. From the perspective of the arm 8, the height H4 of the protrusion 42 is greater than the thickness T8 of the arm 8.

[0113] The height H4 of the protrusions 42 is greater than the height H4 of the protrusions 42 in the first embodiment described with reference to Fig. 10. A gap GP3 is formed between the outer surface 53 and the inner circumferential surface 43 in the radial direction R. In the example shown in Fig. 14, in the radial direction R, the center of the pressing surface 63 in the thickness direction Z is arranged to overlap with the center of the inner circumferential surface 84 in the thickness direction Z.

[0114] The configuration of the base plate 20 of the second embodiment also provides the same effects as those of the first embodiment. When a ball is passed through the mounting hole 83 in the thickness direction Z, the base plate 20 of the second embodiment deforms so that a portion of the claw portion 57 falls toward the gap GP3. When a portion of the claw portion 57 deforms, the deformed portion is positioned in the gap GP3. Therefore, the deformed portion overlaps with the arm 8 in the thickness direction Z.

[0115] As a result, the deformed portion of the base plate 20 makes it less likely to come off the arm 8 in the thickness direction Z. The base plate 20 of the second embodiment can be more firmly connected to the arm 8 than the first embodiment.

[0116] [Third embodiment] 15 is a schematic partial cross-sectional view showing the base plate 20 and arm 8 according to the third embodiment. The inner surface 54 has a back hole surface 61 and a parallel surface 65. The back hole surface 61 is located at the base portion 51 and is connected to the second surface 23. In the example shown in FIG. 15, the back hole surface 61 is formed in an arc shape. The parallel surface 65 is formed from the base portion 51 to the extension portion 52 and connects the back hole surface 61 and the end surface 55.

[0117] The parallel surface 65 is a surface that is approximately parallel to the outer surface 53. The parallel surface 65 extends approximately parallel along the central axis AX. The parallel surface 65 includes an area that corresponds to the pressing surface 63 in the first embodiment. The extension portion 52 has a claw portion 57. A gap GP3 is formed between the outer surface 53 and the inner circumferential surface 84. The protrusion 42 in the third embodiment is formed, for example, by burring.

[0118] The configuration of the base plate 20 of the third embodiment also provides the same effects as those of the above-described embodiments. Because the protrusions 42 can be formed by burring, the base plate 20 can be manufactured more cheaply than by coining. More specifically, the cost of the mold for manufacturing the base plate 20 can be reduced. Although the extension portion 52 has the claw portion 57, it is not necessary for the extension portion 52 to have the claw portion 57.

[0119] [Fourth embodiment] Fig. 16 is a schematic plan view showing the base plate 20 according to the fourth embodiment. Fig. 17 is a view for explaining a case where the base plates 20 according to the fourth embodiment are stacked. As shown in Fig. 16, the connection portion 40 of the base plate 20 has a plurality of (for example, two) protrusions 42. In the example shown in Fig. 16, the plurality of protrusions 42 do not overlap with the line LX or the line LY.

[0120] The first length L1 of the plurality of protrusions 42 is approximately equal to the second length L2 of the plurality of recesses 44. From another perspective, the first length L1 of the plurality of protrusions 42 shown in FIG. 16 is longer than the first length L1 of the plurality of protrusions 42 described with reference to FIG. 5. The second length L2 of the plurality of recesses 44 shown in FIG. 16 is shorter than the second length L2 of the plurality of recesses 44 described with reference to FIG. 5.

[0121] In this embodiment, the angle in the circumferential direction θ of the range in which the protrusions 42 are formed is approximately equal to the angle obtained by dividing 360 degrees by twice the number of the protrusions 42. In the example shown in Fig. 16, the angle in the circumferential direction θ of the range in which one protrusion 42 is formed is approximately equal to 90 degrees.

[0122] In Fig. 17, one base plate 20 is rotated 180 degrees about the line LX and placed on the other base plate 20. In Fig. 17, the other base plate 20 is indicated by a dashed line. As shown in Fig. 17, the protrusions 42 of one base plate 20 and the protrusions 42 of the other base plate 20 are in close contact with each other in the circumferential direction θ.

[0123] The same effects as those of the above-described embodiments can be obtained with the configuration of the base plate 20 of the fourth embodiment. With the base plate 20 of the fourth embodiment, the protrusions 42 of one base plate 20 and the protrusions 42 of the other base plate 20 are in close contact with each other.

[0124] Therefore, it is easier to position the base plate 20 relative to the mounting hole 83 of the arm 8 than the base plate 20 described using Fig. 5. More specifically, with the base plate 20 of the fourth embodiment, it is possible to improve the accuracy of positioning the base plate 20 relative to the mounting hole 83 in the circumferential direction θ.

[0125] [Fifth embodiment] Fig. 18 is a schematic cross-sectional view showing the base plate 20 according to the fifth embodiment. As shown in Fig. 18, the protrusion 42 is inclined in the thickness direction Z from the second surface 23 toward the first surface 22 so as to approach the central axis AX.

[0126] The outer surface 53 and the pressing surface 63 are each inclined in the thickness direction Z from the second surface 23 toward the first surface 22 so as to approach the central axis AX. The angle formed by the outer surface 53 and the first surface 22 is greater than 90 degrees, and the angle is, for example, 92 degrees to 120 degrees.

[0127] The configuration of the base plate 20 of the fifth embodiment also provides the same effects as those of the first embodiment. Because the multiple protrusions 42 are discontinuously formed in the circumferential direction θ, even in the base plate 20 of the fifth embodiment, when a ball is passed through the mounting hole 83 in the thickness direction Z from the second surface 23 toward the first surface 22, the protrusions 42 are pushed outward in the radial direction R so as to fall.

[0128] [Sixth embodiment] 19 is a schematic plan view showing a base plate 20 according to the sixth embodiment. The base plate 20 of the sixth embodiment differs from the above-described embodiments in that it has three protrusions 42.

[0129] As shown in Fig. 19, the connection portion 40 of the base plate 20 has three protrusions 42 and three recesses 44. In the example shown in Fig. 19, the three protrusions 42 are arranged at equal intervals in the circumferential direction θ, and the three recesses 44 are arranged at equal intervals in the circumferential direction θ. The three protrusions 42 are point-symmetric with respect to the central axis line AX.

[0130] The three protrusions 42 do not overlap with the line LX. When one base plate 20 is rotated 180 degrees about the line LX and placed on the other base plate 20, the three protrusions 42 of the one base plate 20 overlap with the three recesses 44 of the other base plate 20, and the three protrusions 42 of the other base plate 20 overlap with the three recesses 44 of the one base plate 20. The three protrusions 42 of one base plate 20 do not overlap with the three protrusions 42 of the other base plate 20.

[0131] The first length L1 of the three protrusions 42 is approximately equal to the second length L2 of the three recesses 44. In the sixth embodiment, the angle in the circumferential direction θ of the range in which one protrusion 42 is formed is approximately equal to 60 degrees.

[0132] The same effects as those of the above-described embodiments can be obtained with the configuration of the base plate 20 of the sixth embodiment. In the base plate 20 of the sixth embodiment, the outer surfaces 53 of the three protrusions 42 are provided at equal intervals with respect to the inner circumferential surface 84 of the mounting hole 83 in the circumferential direction θ.

[0133] This allows the outer surface 53 to press against the inner circumferential surface 84 at equal intervals in the circumferential direction θ when the ball is passed through the mounting hole 83 along the thickness direction Z. As a result, the outer surface 53 is brought into close contact with the inner circumferential surface 84 at equal intervals in the circumferential direction θ, allowing the multiple protrusions 42 to be connected to the mounting hole 83 in a balanced manner.

[0134] In the sixth embodiment, the first length L1 of the three protrusions 42 may be shorter than the second length L2 of the three recesses 44. In this case, when one base plate 20 is rotated 180 degrees about the line LX and the other base plate 20 is placed on top of the other base plate 20, gaps are formed between the protrusions 42 of the one base plate 20 and the protrusions 42 of the other base plate 20 in the circumferential direction θ.

[0135] [Seventh embodiment] 20 is a schematic plan view showing a base plate 20 according to the seventh embodiment. The base plate 20 of the seventh embodiment differs from the above-described embodiments in that it has four protrusions 42.

[0136] As shown in Fig. 20, the connection portion 40 of the base plate 20 has four protrusions 42 and four recesses 44. In the example shown in Fig. 20, the four protrusions 42 are arranged at equal intervals in the circumferential direction θ, and the four recesses 44 are arranged at equal intervals in the circumferential direction θ. The four protrusions 42 are point-symmetric with respect to the central axis line AX.

[0137] The four protrusions 42 do not overlap with the line LX or the line LY. When one base plate 20 is rotated 180 degrees about the line LX and placed on top of the other base plate 20, the four protrusions 42 of the one base plate 20 overlap with the four recesses 44 of the other base plate 20, and the four protrusions 42 of the other base plate 20 overlap with the four recesses 44 of the one base plate 20. The four protrusions 42 of one base plate 20 do not overlap with the four protrusions 42 of the other base plate 20.

[0138] The first length L1 of the four protrusions 42 is approximately equal to the second length L2 of the four recesses 44. In the seventh embodiment, the angle in the circumferential direction θ of the range in which one protrusion 42 is formed is approximately equal to 45 degrees.

[0139] The configuration of the base plate 20 of the seventh embodiment can also achieve the same effects as those of the above-described embodiments. The base plate 20 of the seventh embodiment has more protrusions 42 than the base plate 20 of the sixth embodiment described with reference to Fig. 19. This allows the multiple protrusions 42 to be connected to the mounting holes 83 in a more balanced manner than the base plate 20 of the sixth embodiment described with reference to Fig. 19.

[0140] In the seventh embodiment, the first length L1 of the four protrusions 42 may be shorter than the second length L2 of the four recesses 44. In this case, when one base plate 20 is rotated 180 degrees about the line LX and the other base plate 20 is placed on top of the other base plate 20, gaps are formed between the protrusions 42 of the one base plate 20 and the protrusions 42 of the other base plate 20 in the circumferential direction θ.

[0141] When implementing the invention disclosed in the above embodiments, the specific aspects of each element constituting the disk drive suspension, including the specific aspects of the shapes of the base plate, load beam, and flexure, can be modified in various ways.

[0142] The first lengths L1 of the multiple protrusions 42 may be different from one another. In this case, the angle in the circumferential direction θ of the range in which each of the multiple protrusions 42 is formed may be different from one another. For example, if the multiple protrusions 42 are composed of two protrusions 42, the angle in the circumferential direction θ of the range in which one of the protrusions 42 is formed may be approximately equal to 100 degrees, and the angle in the circumferential direction θ of the range in which the other protrusion 42 is formed may be smaller than 80 degrees.

[0143] Note that one base plate 20 may be shaped so that when another base plate 20 rotated 180 degrees about the line LX is placed on top of the other base plate 20, the multiple protrusions 42 of one base plate 20 do not overlap with the multiple recesses 44 of the other base plate 20. For example, the multiple protrusions 42 of the base plate 20 may be symmetrical with respect to the line LX. Note that the number of multiple protrusions 42 may be five or more. [Explanation of symbols]

[0144] 1...disk device, 8...arm, 10...disk device suspension, 10A...first suspension, 10B...second suspension, 11...slider, 20...base plate, 21...plate body, 31...load beam, 32...flexure, 40...connection portion, 41...through hole, 42...protrusion, 43...inner surface, 44...recess, 83...mounting hole.

Claims

1. A base plate of a suspension for a disk device that is connected to an arm of the disk device, The plate body, a connection portion provided on the plate body, the connecting portion has a through hole penetrating the plate body in a thickness direction of the plate body, a plurality of protrusions provided along an edge of the through hole in a circumferential direction centered on a central axis of the through hole and inserted into a mounting hole of the arm, and an inner circumferential surface formed by the plurality of protrusions and the through hole, the inner circumferential surface has a plurality of recesses formed between the plurality of protrusions, In the circumferential direction, the plurality of protrusions have a first length, In the circumferential direction, the plurality of recesses have a second length that is longer than the first length. Base plate for disk drive suspension.

2. Each of the plurality of protrusions has a root portion connected to the plate body, an extension portion including one end located on the opposite side of the root portion in the thickness direction, and a pressing portion located between the root portion and the one end and having a width in a radial direction intersecting the thickness direction that is larger than that of the root portion.

2. The base plate of the disk drive suspension according to claim 1.

3. a base plate for a disk drive suspension according to claim 1 or 2; a load beam connected to the base plate; a flexure disposed along the load beam. Suspension for disk drives.

4. the base plate includes a plate body and a connection portion provided on the plate body, the connecting portion has a through hole penetrating the plate body in a thickness direction of the plate body, and a plurality of protrusions provided along an edge of the through hole in a circumferential direction centered on a central axis of the through hole and inserted into a mounting hole of the arm, the plurality of protrusions do not overlap with a line that intersects with the central axis and is parallel to the extension direction of the load beam; 4. The disk drive suspension according to claim 3.

5. an arm having a first mounting surface, a second mounting surface opposite the first mounting surface, and a mounting hole penetrating the first mounting surface and the second mounting surface; a first disk device suspension connected to the arm from the first mounting surface side; a second disk device suspension connected to the arm from the second mounting surface side, The first disk drive suspension comprises: a first base plate having a first plate body and a first connection portion provided on the first plate body; a first load beam connected to the first base plate; a first flexure disposed along the first load beam, The second disk drive suspension comprises: a second base plate having a second plate body and a second connection portion provided on the second plate body; a second load beam connected to the second base plate; a second flexure disposed along the second load beam, the first connection portion has a first through hole penetrating the first plate body in a thickness direction of the first plate body, a plurality of first protrusions provided along an edge of the first through hole in a circumferential direction centered on a central axis of the first through hole and inserted into a mounting hole of the arm, and a first inner circumferential surface formed by the plurality of first protrusions and the first through hole, the second connection portion has a second through hole penetrating the second plate body in a thickness direction of the second plate body, a plurality of second protrusions provided along an edge of the second through hole in a circumferential direction centered on a central axis of the second through hole and inserted into a mounting hole of the arm, and a second inner circumferential surface formed by the plurality of second protrusions and the second through hole, the first inner circumferential surface has a plurality of first recesses formed between the plurality of first protrusions, the second inner circumferential surface has a plurality of second recesses formed between the plurality of second protrusions, the first protrusions and the second protrusions are inserted into the mounting holes, respectively; The plurality of first protrusions overlap the plurality of second recesses. Disk device.

6. a height of the plurality of first protrusions and a height of the plurality of second protrusions are greater than a thickness of the arm; 6. The disk device according to claim 5.

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