Load beam, load beam blank panel, and method for manufacturing load beam

Abstract

A load beam according to the present disclosure includes: a beam body extending in a first direction; and a tab extending in the first direction from the beam body to a tip of the load beam. The tab includes a tab body, a thin portion adjacent to the tab body, and a tab end edge portion adjacent to the thin portion and defining an end surface of the tab. The tab end edge portion includes a thick portion that is thicker than the minimum thickness of the thin portion.

Description

Load beam, load beam blank plate, and method of manufacturing the load beam

[0001] The present disclosure relates to a load beam, a load beam blank, and a method for manufacturing a load beam.

[0002] Generally, hard disk drives (HDDs) are equipped with a suspension on which a magnetic head is mounted, which writes and reads data to and from a magnetic disk on which the data is stored. The suspension is primarily composed of a wiring board and a load beam, with the magnetic head mounted on the tip of the wiring board. The load beam functions as a thin flat spring and supports the wiring board so that the magnetic head maintains a desired flying height relative to the magnetic disk.

[0003] Japanese Patent Application Laid-Open No. 2023-053590 U.S. Patent No. 7,446,970 JP 2000-137967 A JP 2012-133848 A JP 2012-164389 A

[0004] The present disclosure aims to provide improved load beams, load beam blanks and methods of manufacturing load beams.

[0005] [1] The present disclosure may also provide a load beam comprising: a beam body extending in a first direction; and a tab extending in the first direction from the beam body to a tip of the load beam, wherein the tab includes a tab body, a thin portion adjacent to the tab body, and a tab edge portion adjacent to the thin portion and defining an end face of the tab, and the tab edge portion includes a thick portion that is thicker than a minimum thickness of the thin portion.

[0006] [2] The present disclosure may be the load beam according to [1], wherein the maximum thickness of the thick portion is smaller than the thickness of the tab body.

[0007] [3] The present disclosure may be the load beam according to [1] or [2], wherein the thickened portion extends along the tab end edge portion.

[0008] [4] The present disclosure may be the load beam according to any one of [1] to [3], wherein the tab end edge portions are located on both sides of the tab main body in a second direction perpendicular to the first direction in a plan view, the thin portion is located between each of the tab end edge portions and the tab main body, and each of the tab end edge portions includes the thick portion.

[0009] [5] The present disclosure may be a load beam according to any one of [1] to [4], wherein the tab includes a tab first surface and a tab second surface located opposite the tab first surface, the tab has a curved shape with the tab first surface facing inward when viewed in a cross section perpendicular to the first direction, and the thin-walled portion includes a concave surface recessed from the tab first surface.

[0010] [6] The present disclosure may be the load beam according to [5], wherein the concave surface is formed in a curved shape when viewed in a cross section perpendicular to the first direction.

[0011] [7] The present disclosure may be a load beam according to any one of [1] to [6], wherein the tab includes a root region adjacent to the beam body and a body region located on the opposite side of the root region from the beam body, and the thick portion is located in the body region.

[0012] [8] The present disclosure may be the load beam according to [7], wherein the thickened portion is located in the root region and the main body region.

[0013] [9] The present disclosure may be a load beam according to any one of [1] to [6], wherein the tab includes a root region adjacent to the beam body and a body region located on the opposite side of the beam body from the root region, and the thickened portion is located in the root region.

[0014]

[10] The present disclosure may be a load beam according to any one of [1] to [9], wherein the tab includes a root region adjacent to the beam body, a tip region including the tip of the load beam, and a body region located between the root region and the tip region, and the thick portion is located in the tip region.

[0015]

[11] The present disclosure may be the load beam according to

[10] , wherein the thin portion and the thick portion are located in the root region, the tip region, and the main body region.

[0016]

[12] The present disclosure may also be directed to a load beam blank plate comprising: a flat-formed blank plate body extending in a first direction; and a flat-formed blank plate tab extending in the first direction from the blank plate body to a tip of the load beam blank plate, wherein the blank plate tab includes a blank plate tab body, a thin portion adjacent to the blank plate tab body, and a tab edge portion adjacent to the thin portion and defining an end face of the blank plate tab, and the tab edge portion includes a thick portion that is thicker than a minimum thickness of the thin portion.

[0017]

[13] The present disclosure may also relate to a load beam comprising: a beam flat portion; and a tab extending from the beam flat portion, wherein the tab has a tab first surface and a tab second surface located opposite the tab first surface, wherein the tab has a shape in which the tab first surface is curved inward in a cross section in a lateral direction perpendicular to a longitudinal direction of the load beam, and wherein the thickness of the tab is thinner at a central portion in the lateral direction of the load beam than at both ends in the lateral direction of the load beam.

[0018]

[14] The present disclosure may be the load beam described in

[13] , wherein the tab second surface has two outer curved surfaces and a central surface located between the two outer curved surfaces, and the central surface is formed discontinuously with the outer curved surfaces.

[0019]

[15] The present disclosure may be the load beam according to

[14] , wherein the central surface is a central flat surface formed flat.

[0020]

[16] The present disclosure may be the load beam according to

[14] , wherein the central surface is a central curved surface formed in a curved shape.

[0021]

[17] The present disclosure may be a load beam according to

[16] , wherein, in the cross section in the short side direction, the outer curved surface and the central curved surface are each formed in an arc shape, and a radius of curvature of the central curved surface is larger than a radius of curvature of the outer curved surface.

[0022]

[18] The present disclosure may be a load beam according to any one of

[13] to

[17] , wherein the thickness of the tab at the central part in the short side direction is 30% to 85% of the thickness of the tab at the end part in the short side direction.

[0023]

[19] The present disclosure may be a method for manufacturing a load beam according to any one of

[13] to

[18] , comprising: a step of preparing a plate-shaped member; a step of forming a thin-walled portion in the center of a portion of the plate-shaped member corresponding to the tab; and a step of bending the portion corresponding to the tab so that the first surface of the tab faces inward after the step of forming the thin-walled portion.

[0024]

[20] The present disclosure may be the method for manufacturing a load beam according to

[19] , wherein the thin-walled portion is formed by etching.

[0025]

[21] The present disclosure may be a method for manufacturing a load beam according to any one of

[13] to

[18] , including: a step of preparing a plate-shaped member; a step of bending a portion corresponding to the tab so that the tab first surface faces inward; and a step of thinning a region including the central portion of the tab second surface after the step of bending the portion corresponding to the tab.

[0026]

[22] The present disclosure may be a method for manufacturing a load beam according to any one of

[13] to

[18] , comprising: a step of preparing a plate-shaped member; and a step of bending a portion corresponding to the tab so that the tab first surface faces inward, and simultaneously thinning a region including the central portion of the tab second surface.

[0027]

[23] The present disclosure may also provide a load beam blank plate comprising: a flat blank plate main body; and a flat blank plate tab extending from the blank plate main body, the blank plate tab having a tab first surface and a tab second surface located opposite the tab first surface, the blank plate tab including a thin portion located in the center in a short direction perpendicular to the long direction of the load beam blank plate, the thin portion being recessed from the tab second surface.

[0028]

[24] The present disclosure may also relate to a load beam comprising: a tab located at a tip of the load beam and extending in a first direction; a beam flat portion extending in the first direction in a tapered manner toward the tab; and a pair of edge portions located on both sides of the beam flat portion in a second direction perpendicular to the first direction in a plan view, the pair of edge portions being bent relative to the beam flat portion, wherein the edge portions include an edge inclined portion extending in a direction inclined with respect to the first direction in a plan view; and an edge curved portion located closer to the tab than the edge inclined portion, the edge curved portion being formed continuously from the edge inclined portion and curved so as to be convex outward in a plan view.

[0029]

[25] The present disclosure may be directed to a load beam as described in

[24] , comprising: a first surface formed from the beam flat portion to the edge portion; and a second surface formed from the beam flat portion to the edge portion, the second surface being located on the opposite side to the first surface, wherein the edge portion has a bent shape with the first surface facing inward, and the second surface at the edge curved portion is formed in a curved shape.

[0030]

[26] The present disclosure may be the load beam according to

[24] or

[25] , wherein the edge curved portion is formed in an arc shape in a plan view, and the radius of the edge curved portion in a plan view is 0.8 mm or more and 1.8 mm or less.

[0031]

[27] The present disclosure may be a load beam according to any one of

[24] to

[26] , comprising: a first surface formed from the beam flat portion to the edge portion; and a second surface formed from the beam flat portion to the edge portion, the second surface being located on the opposite side to the first surface, wherein the edge portion has a bent shape with the first surface facing inward, and the surface roughness of the end face of the edge curved portion is rougher than the surface roughness of the second surface.

[0032]

[28] The present disclosure may be a load beam according to

[27] , wherein a difference between the ten-point mean roughness of the end surface of the edge curved portion and the ten-point mean roughness of the second surface is 0.100 μm or more and 0.350 μm or less.

[0033]

[29] The present disclosure may be a load beam according to

[27] or

[28] , wherein the surface roughness of the end face of the edge inclination portion is greater than the surface roughness of the second surface.

[0034]

[30] The present disclosure may also relate to a load beam blank plate comprising: a blank plate tab located at a tip of the load beam blank plate and extending in a first direction; and a blank plate main body extending in the first direction in a tapered manner toward the blank plate tab, wherein the blank plate main body includes a pair of blank plate inclined end faces extending in a direction inclined with respect to the first direction in a plan view; and a pair of blank plate curved end faces located closer to the blank plate tab than the blank plate inclined end faces, the pair of blank plate curved end faces being formed continuously from the corresponding blank plate inclined end faces and curved so as to be convex outward in a plan view.

[0035] According to the present disclosure, an improved load beam, a load beam blank plate, and a method for manufacturing a load beam can be provided.

[0036] FIG. 1 is a perspective view showing a hard disk drive according to a first embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing a state in which the suspension shown in FIG. 1 is retracted to a ramp. FIG. 3 is a plan view showing a load beam according to the first embodiment of the present disclosure. FIG. 4 is a cross-sectional view taken along line A-A shown in FIG. 3. FIG. 5 is an enlarged plan view of the rear surface of the tab shown in FIG. 3. FIG. 6A is a cross-sectional view taken along line B-B shown in FIG. 5. FIG. 6B is a cross-sectional view taken along line C-C shown in FIG. 5. FIG. 7 is an enlarged cross-sectional view of the thin-walled portion shown in FIGS. 6A and 6B. FIG. 8 is a cross-sectional view showing a load beam blank plate for producing the load beam shown in FIG. 4. FIG. 9A is a cross-sectional view showing the load beam blank plate shown in FIG. 8 in a state before the tab shown in FIG. 6A is formed. FIG. 9B is an enlarged cross-sectional view of the thin-walled portion shown in FIG. 9A. FIG. 10 is a cross-sectional view showing two load beam tabs retracted into the accommodation space of the ramp shown in FIG. 2. FIG. 11 is a plan view showing a modified example of the tab edge portion shown in FIG. 5 , and is an enlarged plan view showing a portion P in FIG. 5 . FIG. 12 is a cross-sectional view taken along line D-D in FIG. 11 . FIG. 13 is a cross-sectional view showing a modified example of the thin portion shown in FIG. 7 . FIG. 14 is a cross-sectional view showing another modified example of the thin portion shown in FIG. 7 . FIG. 15 is a cross-sectional view showing another modified example of the thin portion shown in FIG. 7 . FIG. 16 is a cross-sectional view showing another modified example of the thin portion shown in FIG. 7 . FIG. 17 is a perspective view showing a hard disk drive including a suspension according to a second embodiment of the present disclosure. FIG. 18 is a schematic cross-sectional view showing a state in which the suspension shown in FIG. 17 is retracted to a ramp. FIG. 19 is a plan view showing the suspension shown in FIG. 1 including a load beam according to the second embodiment of the present disclosure. FIG. 20 is a cross-sectional view taken along line E-E in FIG. 19 . FIG. 21 is a cross-sectional view taken along line F-F in FIG. 19 . FIG. 22 is a plan view showing a tab of a load beam according to the second embodiment of the present disclosure. 23A and 24B are cross-sectional views showing a load beam blank plate for fabricating a load beam according to a second embodiment of the present disclosure, respectively.24C is a cross-sectional view showing a method for manufacturing a load beam according to the second embodiment of the present disclosure. FIG. 24D is a cross-sectional view showing a method for manufacturing a load beam according to the second embodiment of the present disclosure. FIG. 24E is a cross-sectional view showing a method for manufacturing a load beam according to the second embodiment of the present disclosure. FIG. 25 is a cross-sectional view showing a tab of a load beam according to a modified example. FIG. 26A is a cross-sectional view showing a method for manufacturing a load beam according to a modified example. FIG. 26B is a cross-sectional view showing a method for manufacturing a load beam according to a modified example. FIG. 26C is a cross-sectional view showing a method for manufacturing a load beam according to a modified example. FIG. 27 is a perspective view showing a hard disk drive according to a third embodiment of the present disclosure. FIG. 28 is a schematic cross-sectional view showing a state in which the suspension shown in FIG. 27 is retracted to the ramp. FIG. 29 is a plan view showing a load beam according to the third embodiment of the present disclosure. FIG. 30 is a cross-sectional view taken along line G-G shown in FIG. 29. FIG. 31 is an enlarged plan view showing the edge curved portion shown in FIG. 29. FIG. 32 is a cross-sectional view taken along line H-H shown in FIG. 31. FIG. 33 is a schematic cross-sectional view showing part Q1 of FIG. 32. Fig. 34 is a partially enlarged plan view showing a load beam blank plate for fabricating the load beam shown in Fig. 29. Fig. 35 is a cross-sectional view showing the load beam blank plate shown in Fig. 34. Fig. 36 is a schematic cross-sectional view showing the interior of the hard disk drive shown in Fig. 27. Fig. 37 is a schematic view showing an airflow flowing in from the tip of the load beam shown in Fig. 29.

[0037] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding.

[0038] As used herein, geometric conditions, physical characteristics, terms specifying the degree of a geometric condition or physical characteristic, and numerical values ​​indicating a geometric condition or physical characteristic may be interpreted without being bound by strict meaning. These geometric conditions, physical characteristics, terms, and numerical values ​​may be interpreted to include a range within which similar functionality can be expected. Examples of terms specifying geometric conditions include "length," "angle," "shape," "parallel," "orthogonal," and "identical." Furthermore, to clarify the drawings, the shapes of multiple parts that can be expected to have similar functionality are depicted in a regular pattern. However, without being bound by strict meaning, the shapes of the parts may differ from each other as long as the functionality can be expected. In the drawings, for convenience, boundary lines indicating the joining surfaces of components are shown as simple straight lines. However, they are not required to be strictly straight lines, and the shape of the boundary line is arbitrary as long as the desired joining performance can be expected.

[0039] 1 to 16, a load beam 10 and a load beam blank plate 60 according to an embodiment of the present disclosure will be described. First, a hard disk drive 1 using a suspension 5 including the load beam 10 according to this embodiment will be described using FIG.

[0040] A load beam may have a thinned portion formed therein for a desired purpose, but if the thinned portion includes an edge portion that defines the contour of the load beam, the edge portion may be deformed or broken, which may cause problems with mechanical strength.

[0041] An object of this embodiment is to provide a load beam and a load beam blank plate that can improve mechanical strength.

[0042] As shown in FIG. 1, a hard disk drive 1 includes a case 2, a magnetic disk 3, a spindle motor 4, a suspension 5, a voice coil motor 6, and a ramp 7. The magnetic disk 3 is configured to store data. The magnetic disk 3 is rotatably attached to the case 2 and is configured to rotate by the spindle motor 4. The suspension 5 includes a wiring board (or flexure) (not shown) and a load beam 10. A magnetic head (not shown) is mounted on the tip of the wiring board. The magnetic head is configured to write and read data to and from the magnetic disk 3. The load beam 10 supports the magnetic head and the wiring board so that the magnetic head maintains a desired flying height relative to the magnetic disk 3 when writing and reading data. The suspension 5 is rotated by the voice coil motor 6, allowing the magnetic head to be moved to a desired position on the magnetic disk 3.

[0043] 1 includes a plurality of magnetic disks 3 and a plurality of suspensions 5 in order to improve recording density. The magnetic heads of the suspensions 5 are configured to write and read data to and from the upper and lower surfaces of each of the magnetic disks 3.

[0044] The ramp 7 is located near the magnetic disk 3 inside the case 2. When the magnetic disk 3 stops rotating, the multiple suspensions 5 retract together from the magnetic disk 3. At the retracted position, a tab 25 (described later) located at the tip of the load beam 10 is accommodated in the ramp 7. The ramp 7 is configured to support the tab 25. More specifically, as shown in FIG. 2 , the ramp 7 includes multiple ramp support portions 7 b, and an accommodation space 7 a for accommodating the tab 25 is defined between two adjacent ramp support portions 7 b. The tab 25 accommodated in the accommodation space 7 a is supported by the ramp support portions 7 b.

[0045] Two tabs 25 are accommodated in one accommodation space 7a. Each tab 25 is supported by the opposing ramp support portion 7b. At this time, the two tabs 25 are pressed toward each other. If the hard disk drive 1 receives an external impact in this state, the tabs 25 may come into contact with each other. In this case, the side edges of the tabs 25 may be deformed or damaged. If the hard disk drive 1 receives an external impact, force is applied to the base of the tab 25. In this case, the base of the tab 25 may be deformed or damaged. The load beam 10 according to this embodiment is configured to address such issues.

[0046] Next, the load beam 10 according to this embodiment will be described.

[0047] As shown in FIG. 3 , the load beam 10 is configured to support the magnetic head (not shown) and wiring board (not shown). The magnetic head is mounted on the tip of the wiring board. The load beam 10 extends in a first direction D1. A direction perpendicular to the first direction D1 in a plan view is defined as a second direction D2. The first direction D1 is a direction from the base of the load beam 10 to the tip 10a in a plan view, and corresponds to a direction along the central axis CL of the load beam 10. The base of the load beam 10 corresponds to the lower part of the load beam 10 in FIG. 3 , and the tip 10a of the load beam 10 corresponds to the upper part of the load beam 10 in FIG. 3 . The plan view refers to the case where the load beam 10 is viewed in the normal direction of a first surface 20a or a second surface 20b (described later).

[0048] The load beam 10 includes a beam body 20 extending in a first direction D1, and a tab 25 extending from the beam body 20 to a tip 10a of the load beam 10 in the first direction D1.

[0049] 3, the beam body 20 extends in a first direction D1 in a plan view. The beam body 20 extends in a generally tapered shape from the base of the load beam 10 toward the tip 10a. The beam body 20 according to this embodiment is a portion that supports a wiring board, excluding the tab 25.

[0050] 3 and 4, the beam main body 20 may include a beam flat portion 21 and a pair of edge portions 22. As shown in Fig. 3, at least one main body opening 23 may be formed in the beam flat portion 21. In the example shown in Fig. 3, two main body openings 23 having different planar shapes are formed. The beam flat portion 21 is not limited to being formed in a strictly flat shape, and is a portion that does not include an intentionally bent portion such as the edge portions 22.

[0051] 3 and 4, the edge portions 22 are located on both sides of the beam flat portion 21 in the second direction D2 in a plan view. The edge portions 22 are portions bent from the beam flat portion 21 along the side edges 10b of the load beam 10. The edge portions 22 extend along the side edges 10b in a plan view. The side edges 10b of the load beam 10 extend in a direction inclined toward the first direction D1 in a plan view. The edge portions 22 have a bent shape with a first surface 20a (described later) facing inward.

[0052] 4, the edge portion 22 includes an inclined portion 22a inclined relative to the beam flat portion 21, and a bent portion 22b located between the beam flat portion 21 and the inclined portion 22a. The inclined portion 22a extends along the side edge 10b of the load beam 10 in a plan view. The bent portion 22b connects the beam flat portion 21 and the inclined portion 22a and is curved in a cross-sectional view.

[0053] 4, the beam body 20 includes a first surface 20a formed from the beam flat portion 21 to the edge portion 22, and a second surface 20b formed from the beam flat portion 21 to the edge portion 22 and located on the opposite side to the first surface 20a. The first surface 20a corresponds to the upper surface shown in FIG. 4, and the second surface 20b corresponds to the lower surface shown in FIG. 4.

[0054] As shown in FIG. 4 , the thickness t1 of the beam flat portion 21 may be, for example, 25.0 μm or more and 35.0 μm or less. Setting the thickness t1 to 25.0 μm or more ensures the mechanical strength of the load beam 10 and reduces the possibility of plastic deformation of the load beam 10. Setting the thickness t1 to 35.0 μm or less reduces the thickness of the load beam 10. This reduces the thickness of the suspension 5, contributing to a reduction in the thickness of the hard disk drive 1. Setting the thickness t1 to 35.0 μm or less increases the separation distance X1 (see FIG. 10 ) between the ramp 7 and the housing space 7a, which will be described later, and reduces the possibility of the two tabs 25 coming into contact with each other. For example, the thickness t1 may be 25.0 μm or more and 30.0 μm or less, 27.0 μm or more and 30.0 μm or less, or 29.0 μm or more and 30.0 μm or less. The thickness t1 is the dimension of the beam flat portion 21 in a direction perpendicular to the second surface 20b.

[0055] Next, the tab 25 will be described.

[0056] 3 and 5, the tab 25 extends in an elongated shape in the first direction D1 from the beam body 20 to the tip 10a of the load beam 10. The tip of the tab 25 constitutes the tip 10a of the load beam 10.

[0057] The tab 25 may include a tab first surface 25a and a tab second surface 25b. The tab first surface 25a is connected to the first surface 20a of the beam main body 20 and may be formed continuously from the first surface 20a. The tab second surface 25b is located on the opposite side to the tab first surface 25a. The tab second surface 25b is connected to the second surface 20b of the beam main body 20 and may be formed continuously from the second surface 20b.

[0058] The tab 25 is formed integrally with the beam body 20. However, after the molding process, the tab 25 has a curved shape with the tab first surface 25a facing inward in a cross section perpendicular to the first direction D1. The tab 25 also has a curved shape with the tab first surface 25a facing inward in a cross section including the central axis CL and perpendicular to the beam flat portion 21. The tab 25 has an overall curved cross-sectional shape. The tab 25 may have an arc-shaped cross-sectional shape. The tab 25 is curved so that the tab second surface 25b faces outward. As shown in FIG. 10 , which will be described later, the tab second surface 25b abuts against the lamp support portion 7b of the lamp 7 described above.

[0059] 6A , the width w1 of the tab 25 may be defined as the dimension along the second tab surface 25b of the tab 25 when viewed in a cross section perpendicular to the first direction D1. For example, the width w1 may be 200 μm or more and 350 μm or less.

[0060] As shown in FIG. 5 , the tab 25 may include a root region 25R1, a main body region 25R2, and a tip region 25R3. The root region 25R1 is adjacent to the beam body 20 and is the region of the tab 25 closest to the beam body 20. The main body region 25R2 is located on the opposite side of the beam body 20 from the root region 25R1 and is farther from the beam body 20 than the root region 25R1. The main body region 25R2 is located between the root region 25R1 and the tip region 25R3. The tip region 25R3 includes the tip 10a of the load beam 10. The tip region 25R3 is located on the opposite side of the beam body 20 from the main body region 25R2 and is farther from the beam body 20 than the main body region 25R2. The tip region 25R3 may be semicircular in plan view. The tip of the tip region 25R3 corresponds to the tip 10a of the load beam 10. The base region 25R1 and the main body region 25R2 may be defined by a boundary at a desired position in the first direction D1. For example, the main body region 25R2 and the tip region 25R3 may be regions that come into contact with the lamp support portion 7b when the tab 25 of the load beam 10 is accommodated in the accommodation space 7a of the lamp 7. The base region 25R1 may be a region that does not come into contact with the lamp support portion 7b.

[0061] 5 to 6B, the tab 25 includes a tab body 26, a thinned portion 28 adjacent to the tab body 26, and a tab edge portion 27 adjacent to the thinned portion 28 and defining an end surface 25c of the tab 25. The thickness t2 of the tab body 26 is equal to the thickness t1 of the beam flat portion 21. The thickness t2 of the tab body 26 is the dimension of the tab body 26 in a direction perpendicular to the tab second surface 25b.

[0062] As shown in FIGS. 5 to 6B , the tab end edge 27 defines an end face 25 c of the tab 25. The end face 25 c defines the outline of the tab 25 in a plan view. The tab end edge 27 is located outside the tab main body 26 and outside the thin-walled portion 28 in a plan view. The tab end edge 27 is adjacent to the thin-walled portion 28. As described above, when the tab 25 has an arc-shaped cross section when viewed in a cross section perpendicular to the first direction D1, the end face 25 c may be formed along the radial direction of the arc of the tab 25. In this case, in a load beam blank plate 60 described later, the end face 25 c may be formed perpendicular to the flat tab second surface 25 b before being formed.

[0063] 5 and 6A, in the root region 25R1 and the main body region 25R2, the tab end edges 27 are located on both sides of the tab main body 26 in the second direction D2. In this case, the tab end edges 27 may be formed linearly along the first direction D1.

[0064] 5 and 6B , in the tip region 25R3, the tab edge 27 is located outside the tab main body 26 in a plan view. In this case, the tab edge 27 may be formed in a semicircular arc shape in a plan view. When viewed in a cross section including the central axis CL and perpendicular to the beam flat portion 21, the tab edge 27 is located at the tip 10a of the load beam 10.

[0065] Next, the thin-walled portion 28 will be described.

[0066] 6A and 6B, the thin-walled portion 28 is adjacent to the tab main body 26. The thin-walled portion 28 is formed thinner than the tab main body 26.

[0067] The thin-walled portion 28 is formed so as to be continuous with the tab second surface 25b. The thin-walled portion 28 includes a concave surface 29 recessed from the tab first surface 25a of the tab 25. The concave surface 29 according to this embodiment may be formed in a curved shape when viewed in a cross section perpendicular to the first direction D1. In this case, the thickness of the thin-walled portion 28 does not have to be constant. The thickness of the thin-walled portion 28 at any position in a plan view may be thinner than the thickness t2 of the tab main body 26.

[0068] In FIG. 7 , the minimum thickness of the thin-walled portion 28 is indicated by t3. This minimum thickness t3 is thinner than the thickness t2 of the tab main body 26. For example, the minimum thickness t3 may be 7.0 μm or greater and 15.0 μm or less. Setting the minimum thickness t3 to 7.0 μm or greater ensures the mechanical strength of the thin-walled portion 28 and reduces the possibility of plastic deformation of the thin-walled portion 28. Setting the minimum thickness t3 to 15.0 μm or less reduces the possibility of the concave surface 29 and end surface 25c of one of the two tabs 25 housed in the housing space 7a of the lamp 7 coming into contact with the concave surface 29 and end surface 25c of the other tab 25. Setting the minimum thickness t3 to 15.0 μm or less reduces the maximum thickness t4 of the thick-walled portion 30. This increases the separation distance X2 (see FIG. 10 ) between the two tabs 25 housed in the housing space 7a of the lamp 7, reducing the possibility of the two tabs 25 coming into contact with each other. The minimum thickness t3 is the dimension of the thin-walled portion 28 in the direction perpendicular to the tab second surface 25b. More specifically, it is the dimension of the thin-walled portion 28 in the direction perpendicular to the tab second surface 25b at the position where the dimension of the thin-walled portion 28 is minimum.

[0069] A first thickness ratio, which is the ratio of the minimum thickness t3 of the thin-walled portion 28 to the thickness t2 of the tab main body 26, may be specified. For example, the first thickness ratio may be 0.2 or greater and 0.5 or less. Setting the first thickness ratio to 0.2 or greater ensures the mechanical strength of the thin-walled portion 28 and reduces the possibility of plastic deformation of the thin-walled portion 28. Setting the first thickness ratio to 0.5 or less reduces the possibility of the concave surface 29 and end surface 25c of one of the two tabs 25 housed in the housing space 7a of the lamp 7 contacting the concave surface 29 and end surface 25c of the other tab 25. Setting the minimum thickness t3 to 15.0 μm or less reduces the maximum thickness t4 of the thick-walled portion 30. This increases the separation distance X2 (see FIG. 10 ) between the two tabs 25 housed in the housing space 7a of the lamp 7, reducing the possibility of the two tabs 25 contacting each other.

[0070] 5, the thinned portion 28 may be located in at least one of the root region 25R1, the main body region 25R2, and the tip region 25R3. The thinned portion 28 may be located in each of the root region 25R1, the main body region 25R2, and the tip region 25R3. The thinned portion 28 may be formed continuously from the root region 25R1 to the tip region 25R3. The thinned portion 28 is located between the tab body 26 and the tab end edge 27.

[0071] 5 and 6A , in the root region 25R1 and the main body region 25R2, the thin-walled portions 28 are located on both sides of the tab main body 26 in the second direction D2. In this case, the thin-walled portions 28 may be formed linearly along the tab end edge portion 27.

[0072] 5 and 6B , in the tip region 25R3, the thin portion 28 is located outside the tab main body 26 in a plan view. In this case, the thin portion 28 may be formed in a semicircular arc shape along the tab end edge 27. When viewed in a cross section including the central axis CL and perpendicular to the beam flat portion 21, the thin portion 28 is located closer to the tip 10a of the load beam 10 than the tab main body 26.

[0073] 6A-7, tab edge 27 may include thickened portion 30. Thickened portion 30 is adjacent to thinned portion .

[0074] The thick portion 30 is a portion that is thicker than the minimum thickness t3 of the thin portion 28. In FIG. 7, the maximum thickness of the thick portion 30 is indicated by t4. The maximum thickness t4 of the thick portion 30 may be thinner than the thickness t2 of the tab main body 26. The thickness of the thick portion 30 does not have to be constant. The maximum thickness t4 of the thick portion 30 at any position may be thicker than the minimum thickness t3 of the thin portion 28, and may be thinner than the thickness t2 of the tab main body 26. In this embodiment, the tab end edge 27 includes the thick portion 30 having the maximum thickness t4.

[0075] As shown in Figure 7, in this embodiment, the thickness of the thick portion 30 gradually increases from the thin portion 28. More specifically, the thick portion 30 includes a thick surface 31 located on the opposite side of the tab second surface 25b, and when viewed in a cross section perpendicular to the first direction D1, the thick surface 31 is curved. The thick surface 31 is curved continuously from the concave surface 29 of the thin portion 28 and has a pointed tip that points toward the inside of the curved shape of the tab 25. The thickness of the thick portion 30 reaches a maximum thickness t4 at the end surface 25c.

[0076] As shown in FIGS. 7 and 9B , the maximum thickness t4 of the thick portion 30 may be greater than the minimum thickness t3 of the thin portion 28. The maximum thickness t4 may be less than the thickness t2 of the tab main body 26. For example, the maximum thickness t4 may be 10 μm or greater and 20 μm or less. Setting the maximum thickness t4 to 10 μm or greater can improve the mechanical strength of the tab edge portion 27 and reduce the possibility of plastic deformation of the tab edge portion 27. Setting the maximum thickness t4 to 20 μm or less can increase the separation distance X2 (see FIG. 10 ) between the two tabs 25 housed in the housing space 7a of the lamp 7, thereby reducing the possibility of the two tabs 25 contacting each other. The maximum thickness t4 is the maximum dimension of the thick portion 30 in a direction perpendicular to the tab second surface 25b. More specifically, it is the dimension of the thick portion 30 in a direction perpendicular to the tab second surface 25b at the position where the dimension of the thick portion 30 is greatest.

[0077] A second thickness ratio, which is the ratio of the maximum thickness t4 of the thick-walled portion 30 to the thickness t2 of the tab main body 26, may be specified. For example, the second thickness ratio may be 0.3 or greater and 0.7 or less. By setting the second thickness ratio to 0.3 or greater, the mechanical strength of the tab edge portion 27 can be improved, reducing the possibility of plastic deformation of the tab edge portion 27. By setting the second thickness ratio to 0.7 or less, the separation distance X2 (see FIG. 10 ), described below, between the two tabs 25 housed in the housing space 7a of the lamp 7 can be increased, reducing the possibility of the two tabs 25 coming into contact with each other.

[0078] As shown in Figures 5 to 6B, the thick portion 30 may be located in at least one of the root region 25R1, the main body region 25R2, and the tip region 25R3. The thick portion 30 may be located in each of the root region 25R1, the main body region 25R2, and the tip region 25R3. The thick portion 30 may be formed continuously from the root region 25R1 to the tip region 25R3. The thick portion 30 may be adjacent to the thin portion 28 and located in the same region as the thin portion 28.

[0079] As shown in FIG. 5, in the root region 25R1 and the main body region 25R2, the thickened portion 30 may be formed linearly along the tab end edge portion 27.

[0080] 5, in the tip region 25R3, the thick portion 30 may be formed in a semicircular arc shape along the tab edge portion 27 while being adjacent to the thin portion 28. As shown in FIG. 6B, when viewed in a cross section including the central axis line CL and perpendicular to the beam flat portion 21, the thick portion 30 is located at the tip 10a of the load beam 10.

[0081] Next, a load beam blank plate 60 for manufacturing the above-mentioned load beam 10 will be described with reference to FIGS. 8, 9A and 9B.

[0082] Fig. 8 shows a cross-sectional view of a load beam blank plate 60 for manufacturing the load beam 10. The cross-sectional view of Fig. 8 corresponds to the cross-sectional view shown in Fig. 4. The load beam blank plate 60 is in a state before the edge portion 22 described above is bent, and is formed flat overall.

[0083] The load beam blank plate 60 includes, in a plan view, a blank plate main body 61 extending in a first direction D1 tapering toward the tip of the load beam blank plate 60, and a blank plate tab 62 (see FIG. 9A ). The tip of the load beam blank plate 60 corresponds to the tip 10a of the load beam 10. The blank plate main body 61 is formed flat and corresponds to the beam main body 20 described above. The blank plate main body 61 is folded along a folding line to separate the beam flat portion 21 and the edge portion 22. The blank plate main body 61 has the main body opening 23 described above.

[0084] As shown in Fig. 8, the first surface 20a and the second surface 20b of the load beam blank plate 60 are each flat. The first surface 20a and the second surface 20b may be parallel to each other. The side edge 10b described above constitutes the side edge of the load beam blank plate 60 in Fig. 8. The thickness of the blank plate body 61 is equal to the thickness t1 of the beam flat portion 21.

[0085] 9A , the blank plate tab 62 is in a state prior to the forming of the tab 25. The blank plate tab 62 extends in an elongated shape in the first direction D1 from the blank plate main body 61 to the tip of the load beam blank plate 60. The blank plate tab 62 is formed flat and continuous with the blank plate main body 61.

[0086] The blank plate tab 62 includes a blank plate tab body 63, a thinned portion 28, and a tab edge portion 27. The blank plate tab body 63 corresponds to the tab body 26 described above. The thickness of the blank plate tab body 63 is equal to the thickness t2 of the tab body 26.

[0087] The thinned portion 28 is adjacent to the blank plate tab main body 63. The thinned portion 28 is formed thinner than the blank plate tab main body 63. The tab edge portion 27 is adjacent to the thinned portion 28 and defines an end face of the blank plate tab 62. The end face of the blank plate tab 62 corresponds to the end face 25c of the tab 25 described above.

[0088] As shown in Fig. 9A, the tab first surface 25a and the tab second surface 25b are formed flat, and the concave surface 29 is formed by cutting out the tab first surface 25a. As shown in Fig. 9A, the thin-walled portion 28 is formed so that the tab second surface 25b is continuous with the thin-walled portion 28. By etching the tab first surface 25a, the concave surface 29 is formed, and as a result, the thin-walled portion 28 and the tab edge portion 27 can be formed. By molding the tab 25 from the state shown in Fig. 9A, the tab 25 shown in Fig. 6A can be obtained.

[0089] The blank plate body 61 may be supported by a frame (not shown) surrounding the blank plate body 61. The load beam 10 according to this embodiment may be obtained by bending the blank plate body 61 while it is supported by the frame. In this case, the load beam 10 may be supported by the frame. A plurality of blank plate bodies 61 may be supported on the frame. In this case, a multi-sided load beam 10 can be produced. A multi-sided load beam 10 refers to a configuration in which a plurality of load beams 10 are supported by a single frame.

[0090] The load beam 10 and the load beam blank plate 60 may be formed of plate-like members. The load beam 10 may be made of, for example, a metal material, such as stainless steel.

[0091] Next, a method for manufacturing the load beam 10 according to this embodiment having the above-described configuration will be described.

[0092] First, a flat plate-like member is prepared. For example, the plate-like member may be a rolled material having the thickness t1 described above.

[0093] Next, a patterned resist layer (not shown) is formed on the tab first surface 25a of the plate-like member by photolithography, and a resist layer is formed on the entire second surface 20b.

[0094] Next, the tab first surface 25a of the plate-like member is etched to form the thin-walled portion 28 as shown in FIGS. 9A and 9B . More specifically, etching the tab first surface 25a forms a concave surface 29, resulting in the thin-walled portion 28. Along with the thin-walled portion 28, a tab edge portion 27 including a thick-walled portion 30 is also formed. Apertures are formed in the resist layer on the tab first surface 25a at positions corresponding to the thin-walled portion 28 and the thick-walled portion 30. In the portion corresponding to the thick-walled portion 30, a plurality of relatively small apertures may be formed in the resist layer to suppress etching erosion. The outer shape of the plate-like member is also processed by etching. In this manner, a load beam blank plate 60 having a desired profile is obtained.

[0095] Thereafter, the blank plate body 61 of the load beam blank plate 60 is bent to form the edge portion 22 shown in Fig. 4. The blank plate tab is subjected to a forming process such as pressing to form the tab 25 having a curved cross section as shown in Figs. 6A and 6B. In this manner, the load beam 10 according to this embodiment is obtained.

[0096] The thin-walled portion 28 of the load beam 10 thus obtained forms a concave surface 29 on the tab first surface 25a of the tab 25. This reduces the possibility of mutual interference between the tabs 25 of two load beams 10 accommodated in the accommodation space 7a of the ramp 7, as shown in FIG. 10 . That is, as shown in FIGS. 6A and 6B , the thin-walled portion 28 eliminates a corner 25d at the intersection of the tab first surface 25a and the end surface 25c of the tab 25. For example, the maximum thickness t4 of the thick-walled portion 30 of the tab end edge 27 is smaller than the thickness t2 of the tab body 26, so the corner 25d can be eliminated. Therefore, as shown in FIG. 10 , the separation distances X1 and X2 between the two tabs 25 can be increased, reducing the possibility of mutual contact between the two tabs 25 accommodated in one accommodation space 7a of the ramp 7. The separation distance X1 is the distance between the intersections of the tab first surfaces 25a and the concave surfaces 29 of the respective tabs 25 when viewed in the cross section shown in Fig. 10. The separation distance X2 is the distance between the thick portions 30 of the respective tabs 25 when viewed in the cross section shown in Fig. 10. In this embodiment, as shown in Fig. 7, the separation distance X2 is the distance between the intersections of the thick surfaces 31 and the end surfaces 25c of the respective tabs 25. This is also true in the examples shown in Figs. 14 and 15, which will be described later. In the example shown in Fig. 13, which will be described later, the separation distance X2 is the distance between the thick surfaces 31 of the respective tabs 25.

[0097] As described above, according to this embodiment, the tab edge 27, which defines the end surface 25c of the tab 25, is adjacent to the thin portion 28 adjacent to the tab main body 26 of the load beam 10. The tab edge 27 includes a thick portion 30 that is thicker than the minimum thickness t3 of the thin portion 28. This improves the mechanical strength of the tab edge 27, and as a result, the mechanical strength of the tab 25. Furthermore, this reduces the possibility of the tab edge 27 being deformed or damaged during handling of the load beam 10. In this case, it reduces the possibility of foreign matter being generated inside the hard disk drive 1 due to damage to the tab edge 27.

[0098] According to this embodiment, the maximum thickness t4 of the thick portion 30 is thinner than the thickness t2 of the tab main body 26. This makes it possible to remove the corner 25d, which is the intersection of the tab first surface 25a and the end surface 25c of the tab 25. This makes it possible to increase the separation distances X1 and X2 between the two tabs 25 housed in one housing space 7a of the lamp 7, thereby reducing the possibility of the two tabs 25 coming into contact with each other.

[0099] According to this embodiment, the thick portion 30 extends along the tab edge portion 27. This further improves the mechanical strength of the tab edge portion 27, and further improves the mechanical strength of the tab 25.

[0100] According to this embodiment, the tab end edges 27 are located on both sides of the tab main body 26 in the second direction D2 that is perpendicular to the first direction D1 in a plan view. A thin portion 28 is located between each tab end edge 27 and the tab main body 26, and each tab end edge 27 includes a thick portion 30. This further improves the mechanical strength of each tab end edge 27, and further improves the mechanical strength of the tab 25.

[0101] According to this embodiment, the tab 25 has a curved shape with the tab first surface 25a facing inward when viewed in a cross section perpendicular to the first direction D1. The thin-walled portion 28 includes a concave surface 29 recessed from the tab first surface 25a. This makes it possible to remove a corner 25d, which is the intersection of the tab first surface 25a and the end surface 25c of the tab 25, and the area surrounding the corner 25d. This makes it possible to increase the separation distances X1 and X2 between the two tabs 25 housed in one housing space 7a of the lamp 7, further reducing the possibility of the two tabs 25 coming into contact with each other.

[0102] According to this embodiment, the concave surface 29 is formed in a curved shape when viewed in a cross section perpendicular to the first direction D1. This allows the cross section of the thin-walled portion 28 to be formed in a smooth shape, thereby alleviating stress. This further improves the mechanical strength of the tab 25.

[0103] According to this embodiment, the thick portion 30 is located in the main body region 25R2. This improves the mechanical strength of the main body region 25R2. Therefore, even if the suspension 5 is housed in the housing space 7a of the ramp 7 and the hard disk drive 1 receives an external impact, the possibility of the main body region 25R2 of the tab 25 being deformed or damaged can be reduced.

[0104] According to this embodiment, the thick portion 30 is located not only in the main body region 25R2 but also in the root region 25R1. This improves the mechanical strength of the root region 25R1. Therefore, even if the suspension 5 is housed in the housing space 7a of the ramp 7 and the hard disk drive 1 receives an external shock, the possibility of the root region 25R1 of the tab 25 being deformed or damaged can be reduced. In other words, the mechanical strength can be improved in both the main body region 25R2 and the root region 25R1.

[0105] According to this embodiment, the thick portion 30 is located in the tip region 25R3. This improves the mechanical strength of the tip region 25R3. Therefore, even if the suspension 5 is housed in the housing space 7a of the ramp 7 and the hard disk drive 1 receives an external impact, the possibility of deformation or damage to the main body region 25R2 of the tab 25 is reduced.

[0106] According to this embodiment, the thick portion 30 is located in the root region 25R1, the main body region 25R2, and the tip region 25R3. This improves the mechanical strength of each of the root region 25R1, the main body region 25R2, and the tip region 25R3. Therefore, even if the suspension 5 is housed in the housing space 7a of the ramp 7 and the hard disk drive 1 receives an external impact, the possibility of deformation or damage to each of the regions 25R1 to 25R3 of the tab 25 can be reduced. In other words, the mechanical strength of the entire tab 25 can be improved.

[0107] (Variation 1) In the above-described embodiment, the thick portion 30 extends along the tab edge 27. However, the present embodiment is not limited to this. For example, as shown in FIG. 11 , the tab edge 27 may include multiple thick portions 30 spaced apart along the tab edge 27. Even in this case, the mechanical strength of the tab edge 27 can be improved. The maximum thicknesses t4 of the thick portions 30 may be equal to or different from each other. While FIG. 11 illustrates an example in which the tab edge 27 includes multiple thick portions 30, the number of thick portions 30 may be one or any number. The planar shape of the thick portions 30 is arbitrary. As shown in FIG. 12 , at locations of the tab edge 27 where no thick portions 30 are formed, the thickness of the tab edge 27 may be any thickness smaller than the maximum thickness t4 of the thick portions 30 and may be equal to the minimum thickness t3 of the thin portions 28. The example shown in FIG. 11 shows the tab edge portion 27 located in the root region 25R1 or the main body region 25R2 of the tab 25, but the tab edge portion 27 located in the tip region 25R3 may also include multiple thickened portions 30.

[0108] (Variation 2) In the present embodiment described above, the tab end edges 27 in the root region 25R1 and the main body region 25R2 are located on both sides of the tab main body 26 in the second direction D2, and each of the tab end edges 27 includes a thick portion 30. However, this embodiment is not limited to this. For example, if one of the two tab end edges 27 includes a thick portion, the other does not necessarily have to include a thick portion. Similarly, in the tip region 25R3, if one of the two tab end edges 27 located on both sides of the central axis CL includes a thick portion 30, the other does not necessarily have to include a thick portion 30.

[0109] (Variation 3) In the above-described embodiment, an example has been described in which the thick portion 30 is located in the root region 25R1, the main body region 25R2, and the tip region 25R3. However, this embodiment is not limited to this. For example, the thick portion 30 may be located in at least one of the root region 25R1, the main body region 25R2, and the tip region 25R3. For example, the thick portion 30 may be located in one of the root region 25R1, the main body region 25R2, and the tip region 25R3, or in two of the root region 25R1, the main body region 25R2, and the tip region 25R3. In either case, the possibility of the main body region 25R2 of the tab 25 being deformed or damaged by an external impact to the hard disk drive 1 can be reduced.

[0110] (Variation 4) In the above-described embodiment, an example has been described in which the thick surface 31 of the thick portion 30 has a pointed shape that points inward. However, this embodiment is not limited to this. For example, as shown in FIG. 13 , the thick surface 31 of the thick portion 30 may be formed in an arc shape that protrudes inward from the curved shape of the tab 25. The thick surface 31 may also be formed in a semicircular shape. In this case, even if the hard disk drive 1 receives an external impact and the tabs 25 come into contact with each other, the possibility of the tab edge 27 being deformed or damaged can be further reduced. This further reduces the possibility of foreign matter being generated inside the hard disk drive 1 due to damage to the tab edge 27.

[0111] 13, the concave surface 29 of the thin-walled portion 28 includes a portion that is formed concentrically with the tab second surface 25b, and the thickness of the thin-walled portion 28 is the minimum thickness t3 at this concentric portion. This concentric portion may be parallel to the tab second surface 25b before the tab 25 is formed. However, as shown in FIG. 7, the concave surface 29 of the thin-walled portion 28 may be formed in a curved shape without including a concentric portion.

[0112] 14, instead of the example shown in Fig. 13, the thick surface 31 of the thick portion 30 may include a portion formed concentrically with the tab second surface 25b. This concentric portion may be parallel to the tab second surface 25b before the tab 25 is formed. In this case, the recognition accuracy of the end surface 25c of the tab 25 can be improved during the forming process of the tab 25, and the forming accuracy of the tab 25 can be improved.

[0113] 14, the concave surface 29 of the thin-walled portion 28 includes a portion that is formed concentrically with the tab second surface 25b, and the thickness of the thin-walled portion 28 is the minimum thickness t3 at this concentric portion. This concentric portion may be parallel to the tab second surface 25b before the tab 25 is formed. However, as shown in FIG. 7, the concave surface 29 of the thin-walled portion 28 may be formed in a curved shape without including a concentric portion.

[0114] As shown in FIG. 15 , the width w2 of the thin portion 28 and the tab edge portion 27 may be larger than that shown in FIG. 7 . The width w2 is the distance between the intersection of the tab first surface 25a and the concave surface 29 and the intersection of the end surface 25c and the thick surface 31. The width w2 is the distance between the intersection of the tab first surface 25a and the concave surface 29 and the intersection of the end surface 25c and the tab first surface 25a, measured along the extension plane of the tab first surface 25a. The intersection of the end surface 25c and the tab first surface 25a is located at the same position as the corner 25d shown in FIG. 6A . The width w2 may be, for example, 25 μm or more and 40 μm or less. By setting the width w2 to 25 μm or more, the separation distance X1 can be increased. By setting the width w2 to 40 μm or less, the mechanical strength of the tab 25 can be ensured.

[0115] A width ratio, which is the ratio of the width w2 of the thin-walled portion 28 and the tab edge portion 27 to the width w1 of the tab 25 described above, may be specified. For example, the width ratio may be 0.08 or more and 0.20 or less. By setting the width ratio to 0.08 or more, the separation distance X1 can be increased. By setting the width ratio to 0.20 or less, the mechanical strength of the tab 25 can be ensured.

[0116] (Variation 5) In the above-described embodiment, the end surface 25c defining the outline of the tab 25 is formed along the radial direction of the arc of the tab 25 when viewed in a cross section perpendicular to the first direction D1. However, this embodiment is not limited to this. The shape of the end surface 25c is arbitrary. For example, as shown in FIG. 16 , when viewed in a cross section perpendicular to the first direction D1, the end surface 25c may be inclined with respect to the radial direction of the arc of the tab 25. The end surface 25c may be inclined so as to approach the inner side of the curved shape of the tab 25 as it approaches the tab second surface 25b. In this case, in the load beam blank plate 60, the end surface 25c may be inclined with respect to the flat tab second surface 25b before forming. The inclined end surface 25c in the tip region 25R3 can reduce turbulence of the airflow flowing into the tip 10a of the load beam 10. This reduces the pressure that the tip region 25R3 of the load beam 10 receives from the airflow. Furthermore, when the end face 25c is inclined, the internal stress of the tab end edge 27 can be alleviated and the possibility of stress concentration can be reduced when the tab end edge 27 is subjected to an external force, thereby improving the mechanical strength of the load beam 10.

[0117] Alternatively, although not shown, the end surface 25c may include two curved surfaces when viewed in a cross section perpendicular to the first direction D1. One curved surface may be formed by etching the tab second surface 25b and connected to the tab second surface 25b. The other curved surface may be formed by etching the tab first surface 25a and connected to the thick surface 31. This configuration also reduces the turbulence of the airflow flowing into the tip 10a of the load beam 10 and the pressure exerted by the airflow on the tip region 25R3 of the load beam 10. When the tab edge 27 is subjected to an external force, the internal stress of the tab edge 27 can be alleviated, reducing the possibility of stress concentration. This improves the mechanical strength of the load beam 10.

[0118] Second Embodiment Next, a load beam, a load beam blank plate, and a method for manufacturing a load beam according to a second embodiment of the present disclosure will be described with reference to FIGS. 17 to 26C.

[0119] The second embodiment shown in Figures 17 to 26C differs mainly in that the thickness of the tab is thinner at the center of the load beam in the lateral direction than at both ends in the lateral direction. Other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 16. In Figures 17 to 26C, the same parts as those of the first embodiment shown in Figures 1 to 16 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0120] When the magnetic disk stops rotating, the suspensions move together and retract from the magnetic disk. At the retracted position, the tab at the tip of the load beam is housed in the ramp.

[0121] The present embodiment provides a load beam, a load beam blank plate, and a method for manufacturing a load beam that can prevent tabs located at the tip of the load beam from contacting each other when the load beam is housed in a ramp.

[0122] The present embodiment will be described below.

[0123] 17 to 26C, a suspension, a load beam, a load beam blank plate, and a method for manufacturing a load beam according to an embodiment of the present disclosure will be described. First, a hard disk drive 1 using a suspension 5 having a load beam 120 according to this embodiment will be described with reference to FIG.

[0124] As shown in FIG. 17 , the hard disk drive 1 includes a case 2, a magnetic disk 3, a spindle motor 4, a suspension 5, a voice coil motor 6, and a ramp 7. The magnetic disk 3 is configured to store data. The magnetic disk 3 is rotatably attached to the case 2. The magnetic disk 3 is configured to rotate by the spindle motor 4. The suspension 5 includes a flexure 11 and a load beam 120 (see FIG. 19 ). A magnetic head 12 (see FIG. 19 ) is mounted on the tip of the flexure 11. The magnetic head 12 is configured to write and read data to and from the magnetic disk 3. The load beam 120 supports the magnetic head 12 and the flexure 11 so that the magnetic head 12 maintains a desired flying height relative to the magnetic disk 3 when writing and reading data. The suspension 5 is rotated by the voice coil motor 6, allowing the magnetic head 12 to move to a desired position on the magnetic disk 3.

[0125] 17 includes a plurality of magnetic disks 3 and a plurality of suspensions 5 in order to improve recording density. A suspension 5 is provided above and below each of the magnetic disks 3, and a magnetic head 12 mounted on the suspension 5 writes and reads data to and from the magnetic disks 3.

[0126] The ramp 7 is located near the magnetic disk 3 inside the case 2. When the magnetic disk 3 stops rotating, the suspensions 5 move together and retract from the magnetic disk 3. At the retracted position, a tab 122 (described later) located at the tip of the load beam 120 is accommodated in the ramp 7. The ramp 7 is configured to support the tab 122.

[0127] 18, the lamp 7 includes a plurality of lamp support portions 7b. An accommodation space 7a is defined between two adjacent lamp support portions 7b to accommodate the tab 122. The tab 122 accommodated in the accommodation space 7a is supported by the lamp support portions 7b.

[0128] Two tabs 122 are accommodated in one storage space 7a. Each tab 122 is supported by an opposing lamp support portion 7b. The lamp support portion 7b has an inclined portion 7c and a recessed portion 7d. The inclined portion 7c is located on the entrance side of the tab 122. The inclined portion 7c has an inclined surface 7e on the storage space 7a side. The inclined surface 7e is inclined with respect to the horizontal. In the storage space 7a, the inclined surfaces 7e of the two opposing lamp support portions 7b are inclined so that the storage space 7a becomes wider as it moves away from the inclined portion 7c. When accommodating the tabs 122, the two tabs 122 move along their respective inclined surfaces 7e while gradually approaching each other. During this time, the tabs 122 come into contact with the inclined surface 7e. The recessed portion 7d is where the two tabs 122 are accommodated. The storage space 7a is formed between the recessed portions 7d of the two lamp support portions 7b. The surfaces 7f of the recessed portions 7d of the two lamp support portions 7b are parallel to each other across the accommodation space 7a. The surfaces 7f may be parallel to the horizontal direction.

[0129] When the two tabs 122 are accommodated, they are pressed toward each other. If the two tabs 122 move along the inclined surface 7e in this state, there is a risk that the tabs 122 may come into contact with each other. In this case, there is a possibility that the side edges of the tabs 122 may be deformed or damaged. The load beam 120 according to this embodiment is configured to address this issue.

[0130] Next, the suspension 5 according to this embodiment will be described.

[0131] As shown in FIG. 19, the suspension 5 includes a flexure 11, a load beam 120, a first piezoelectric element PZ1, and a second piezoelectric element PZ2.

[0132] The flexure 11 is a flexible wiring board. The flexure 11 is joined to and supported by the load beam 120. The flexure 11 includes a plurality of wires. A magnetic head 12 is mounted on the tip of the flexure 11. Some of the wires electrically connect the magnetic head 12 to terminals connected to an external connection board (not shown). Other wires electrically connect each piezoelectric element (described later) to terminals connected to the external connection board. The flexure 11 is also called a wired flexure or a suspension flexure.

[0133] The load beam 120 extends in the longitudinal direction D11 in a tapered manner toward a tip 120p. As shown in Fig. 20 , the load beam 120 includes a first surface 120a and a second surface 120b located on the opposite side to the first surface 120a. The first surface 120a corresponds to the upper surface in Fig. 20 , and the second surface 120b corresponds to the lower surface in Fig. 20 . The load beam 120 will be described later.

[0134] The first piezoelectric element PZ1 is an example of an actuator element. The first piezoelectric element PZ1 is located on the opposite side of a hinge portion 126 (described later) of the load beam 120 from a tip end 120p of the load beam 120.

[0135] The first piezoelectric element PZ1 is bonded to the first surface 120a of the load beam 120. The first piezoelectric element PZ1 expands and contracts when a voltage is applied, and moves the magnetic head via the load beam 120 and the flexure 11. The first piezoelectric element PZ1 is set so that the expansion and contraction force when a voltage is applied is greater than that of the second piezoelectric element PZ2.

[0136] Two first piezoelectric elements PZ1 are bonded to the load beam 120. The two first piezoelectric elements PZ1 function to move the tip of the suspension 5 in the short-side direction D12. The two first piezoelectric elements PZ1 may be positioned symmetrically with respect to the central axis CL in a plan view. The two first piezoelectric elements PZ1 have opposite polarities. Each first piezoelectric element PZ1 expands and contracts when a voltage is applied, thereby slightly moving the magnetic head. Each first piezoelectric element PZ1 has a pair of opposing electrodes and a piezoelectric material portion interposed between the pair of electrodes. The piezoelectric material portion of each first piezoelectric element PZ1 is made of piezoelectric ceramics such as PZT (lead zirconate titanate). The piezoelectric material portions of the pair of first piezoelectric elements PZ1 are formed so that their polarization directions are 180° apart from each other. When a predetermined voltage is applied to the pair of first piezoelectric elements PZ1, one of the first piezoelectric elements PZ1 contracts, while the other first piezoelectric element PZ1 expands.

[0137] The second piezoelectric element PZ2 is an example of a tip actuator element. The second piezoelectric element PZ2 may also be referred to as a tip piezoelectric element. The second piezoelectric element PZ2 is located closer to the tip 120p of the load beam 120 than the first piezoelectric element PZ1. The second piezoelectric element PZ2 is located closer to the tip 120p of the load beam 120 than a jig hole 127 of the load beam 120, which will be described later.

[0138] The second piezoelectric element PZ2 is bonded to the flexure 11. In this case, the second piezoelectric element PZ2 faces the second surface 120b of the load beam 120. The second piezoelectric element PZ2 expands and contracts when a voltage is applied, and moves the magnetic head 12 via the flexure 11. The second piezoelectric element PZ2 is set so that the expansion and contraction force when a voltage is applied is smaller than that of the first piezoelectric element PZ1.

[0139] Two second piezoelectric elements PZ2 are bonded to the flexure 11. The two second piezoelectric elements PZ2 may be positioned symmetrically with respect to the central axis line CL in a plan view. The polarities of the two second piezoelectric elements PZ2 are different from each other.

[0140] Next, the load beam 120 according to this embodiment will be described.

[0141] As shown in FIG. 19 , the load beam 120 is configured to support the flexure 11 described above. The load beam 120 has a longitudinal direction D11 and a lateral direction D12. The load beam 120 extends in the longitudinal direction D11 so as to taper toward the tip 120p. The longitudinal direction D11 may be referred to as a first direction. The lateral direction D12 is perpendicular to the longitudinal direction D11 in a plan view. The lateral direction D12 may be referred to as a second direction. The plan view means that the load beam 120 is viewed in the normal direction of the first surface 120a at a beam flat portion 124 described later.

[0142] 19, the load beam 120 has a central axis CL along a longitudinal direction D11. The load beam 120 includes a tab 122 located at the tip side of the load beam 120 and a first piezoelectric element opening 129.

[0143] As shown in FIG. 19, the load beam 120 includes a base portion 123 , a beam flat portion 124 , a pair of edge portions 125 , and a hinge portion 126 .

[0144] The base portion 123 is located at the base of the load beam 120. A base plate (not shown) is joined to a first surface 120a of the base portion 123. A first piezoelectric element opening 129 is formed in the base portion 123.

[0145] The beam flat portion 124 is located closer to the tip 120p of the load beam 120 than the base portion 123. The beam flat portion 124 extends in the longitudinal direction D11. The beam flat portion 124 extends in a generally tapered shape toward the tip 120p of the load beam 120. The beam flat portion 124 is formed in a flat shape. The beam flat portion 124 does not necessarily have to be formed in a strictly flat shape, and does not include an intentionally bent portion such as the edge portion 125.

[0146] A jig hole 127 is formed in the beam flat portion 124. The jig hole 127 is located closer to the tip 120p of the load beam 120 than a hinge portion 126, which will be described later. A laser diode element opening 128, which accommodates a laser diode element (not shown), is formed in the beam flat portion 124. The laser diode element opening 128 is located closer to the tip 120p of the load beam 120 than the jig hole 127. The laser diode element is attached to the magnetic head 12 and is installed so as to pass through the laser diode element opening 128.

[0147] 19 , the edge portions 125 are located on both sides of the beam flat portion 124 in the short-side direction D12 in a plan view. The edge portions 125 are portions bent with respect to the beam flat portion 124. The edge portions 125 have a bent shape with the first surface 120a facing inward.

[0148] As shown in FIG. 19 , the hinge portion 126 is located between the base portion 123 and the beam flat portion 124. The hinge portion 126 connects the base portion 123 and the beam flat portion 124. The hinge portion 126 is bent with the second surface 120b facing inward so that the magnetic head 12 approaches the magnetic disk 3. The hinge portion 126 is formed to have low bending rigidity. More specifically, the hinge portion 126 includes a pair of hinge beams 126a, and the base portion 123 and the beam flat portion 124 are connected by the pair of hinge beams 126a. The pair of hinge beams 126a are spaced apart from each other in the short-side direction D12, and an opening is formed between the pair of hinge beams 126a. As a result, when the beam flat portion 124 is affected by an airflow generated by the rotation of the magnetic disk 3, the hinge portion 126 elastically deforms, allowing the magnetic head to maintain a desired flying height relative to the magnetic disk 3. A bending line (not shown) of the hinge portion 126 is aligned along the short-side direction D12. The hinge portion 126 is formed flat along the short-side direction D12.

[0149] 19 , the tab 122 extends in an elongated shape in the longitudinal direction D11 from the beam flat portion 124 to the tip 120p of the load beam 120. The tip of the tab 122 forms the tip 120p of the load beam 120. The tab 122 is supported by the ramp 7 when the suspension 5 is retracted onto the ramp 7. The tab 122 may have a curved shape with the first surface 120a facing inward in a cross section perpendicular to the longitudinal direction D11.

[0150] The first piezoelectric element opening 129 is an opening for the first piezoelectric element PZ1 to mount the first piezoelectric element PZ1 on the load beam 120. The first piezoelectric element opening 129 is formed in the base portion 123 and penetrates the base portion 123. The first piezoelectric element opening 129 is located on the opposite side of the hinge portion 126 from the tip 120p of the load beam 120. The first piezoelectric element opening 129 is formed in a rectangular shape along the longitudinal direction D11 and the lateral direction D12 in a plan view. The first piezoelectric element PZ1 is bonded to the first surface 120a of the load beam 120 so as to overlap the first piezoelectric element opening 129. The first piezoelectric element PZ1 and the wiring of the flexure 11 are electrically connected via a connection portion (not shown) located in the first piezoelectric element opening 129.

[0151] 19, two first piezoelectric element openings 129 are formed in the base portion 123. The two first piezoelectric element openings 129 may be positioned symmetrically with respect to the central axis line CL in a plan view.

[0152] As shown in FIG. 20 , the maximum thickness t11 of the beam flat portion 124 may be, for example, 25.0 μm or more and 35.0 μm or less. Setting the maximum thickness t11 to 25.0 μm or more ensures the mechanical strength of the load beam 120 and reduces the possibility of plastic deformation of the load beam 120. Setting the maximum thickness t11 to 35.0 μm or less reduces the thickness of the load beam 120. This reduces the thickness of the suspension 5, contributing to a reduction in the thickness of the hard disk drive 1. Setting the maximum thickness t11 to 35.0 μm or less increases the separation distance X11 (see FIG. 18 ) between the tabs 122 housed in the housing space 7a of the ramp 7, thereby reducing the possibility of the two tabs 122 coming into contact with each other. For example, the maximum thickness t11 may be 25.0 μm or more and 30.0 μm or less, 27.0 μm or more and 30.0 μm or less, or 29.0 μm or more and 30.0 μm or less. The maximum thickness t11 is the dimension of the beam flat portion 124 in the normal direction D13 of the first surface 120a, and is the distance between the first surface 120a and the second surface 120b in the beam flat portion 124.

[0153] Next, the tab 122 will be described.

[0154] 20 and 22, the tab 122 extends in an elongated shape in the longitudinal direction D11 from the beam flat portion 124 to the tip 120p of the load beam 120. The tip of the tab 122 constitutes the tip 120p of the load beam 120.

[0155] The tab 122 may include a tab first surface 122a and a tab second surface 122b. The tab first surface 122a is connected to the first surface 120a of the load beam 120. The tab first surface 122a is formed continuously from the first surface 120a. The tab second surface 122b is located on the opposite side of the tab first surface 122a. The tab second surface 122b is connected to the second surface 120b of the load beam 120. The tab first surface 122a is formed continuously from the second surface 120b.

[0156] The tab 122 is formed integrally with the beam flat portion 124. The tab 122 has a curved shape in a cross section perpendicular to the longitudinal direction D11. The tab 122 has a tab first surface 122a curved inward. The tab 122 also has a curved shape with the tab first surface 122a facing inward in a cross section that includes the central axis CL and is perpendicular to the beam flat portion 124. The tab 122 has an overall curved cross section. The tab 122 is curved so that the tab second surface 122b faces outward. As shown in FIG. 18 , a portion of the tab second surface 122b abuts against the lamp support portion 7b of the lamp 7 described above.

[0157] 21 , the width w11 of the tab 122 is defined as the dimension along the short-side direction D12 of the tab 122 when viewed in a cross section perpendicular to the long-side direction D11. For example, the width w11 may be 200 μm or more and 350 μm or less.

[0158] As shown in FIG. 21 , in a cross section perpendicular to the longitudinal direction D11, the tab 122 has end portions 122d in the short-side direction D12 and a central portion 122c in the short-side direction D12. The central portion 122c is located at the center in the short-side direction D12 between the end portions 122d. The central portion 122c is located on the tab second surface 122b at a position that is ½ of the width w11 of the tab 122. The end portions 122d are the outermost positions on the tab first surface 122a or the tab second surface 122b in the short-side direction D12, and are positions that can determine the thickness t12 of the tab 122 (described later). In FIG. 21 , the end portions 122d are located on the tab first surface 122a. The end portions 122d may be located on the tab second surface 122b, or on both the tab first surface 122a and the tab second surface 122b.

[0159] 21 , in a cross section perpendicular to the longitudinal direction D11, the thickness t12 of the tab 122 is not uniform along the center line CT of the tab 122. Specifically, the thickness t12 of the tab 122 is thinner at a central portion 122c in the short-side direction D12 than at both end portions 122d in the short-side direction D12. The thickness t12 of the tab 122 refers to the distance between the tab first surface 122a and the tab second surface 122b in a direction perpendicular to the center line CT of the tab 122 in a cross section perpendicular to the longitudinal direction D11. The thickness t12 also refers to the locus of the center line CT of the tab 122 and the center point of a circle RT inscribed in the tab 122 in a cross section perpendicular to the longitudinal direction D11.

[0160] The thickness t12 of the tab 122 at the end 122d in the short-side direction D12 may be, for example, 25.0 μm or more and 35.0 μm or less. The thickness t12 of the tab 122 at the central portion 122c in the short-side direction D12 may be 30% or more and 85% or less, or 30% or more and 50% or less, of the thickness t12 of the tab 122 at the end 122d in the short-side direction D12. The thickness t12 of the tab 122 at the central portion 122c in the short-side direction D12 may be 10 μm or more and 25 μm or less, or 10 μm or more and 15 μm or less. In the example shown in FIG. 21 , the central portion 122c is located on a central flat surface 122f, and the central flat surface 122f is formed to straddle the central portion 122c.

[0161] In the present embodiment, the tab second surface 122b has two outer curved surfaces 122e and a central flat surface 122f. The central flat surface 122f is located between the two outer curved surfaces 122e. The central flat surface 122f is formed flat. The central flat surface 122f is an example of a central surface. The central flat surface 122f may be formed discontinuously with the outer curved surfaces 122e. The outer curved surfaces 122e are curved with the tab first surface 122a side facing inward. In a cross section perpendicular to the longitudinal direction D11, the outer curved surfaces 122e may have an arc shape. In a cross section perpendicular to the longitudinal direction D11, the radius of curvature Rc of the outer curved surfaces 122e may be 100 μm or more and 200 μm or less, or 100 μm or more and 150 μm or less. In a cross section perpendicular to the longitudinal direction D11, the central flat surface 122f extends linearly. The central portion 122c is located on the central flat surface 122f. The width w12 of the central flat surface 122f in the short direction D12 may be 20% to 70% or 40% to 70% of the width w11 of the tab 122. The width w12 of the central flat surface 122f in the short direction D12 may be 60 μm to 200 μm or 120 μm to 200 μm.

[0162] The thickness t12 of the tab 122 may be uniform in the region corresponding to the outer curved surface 122 e. The thickness t12 of the tab 122 may be non-uniform in the region corresponding to the central flat surface 122 f. In the region corresponding to the central flat surface 122 f, the thickness t12 of the tab 122 may gradually become thinner from the outer curved surface 122 e side toward the central portion 122 c side.

[0163] The maximum height t13 of the tab 122 may be, for example, 50 μm or more and 100 μm or less. By making the maximum height t13 of the tab 122 50 μm or more, the mechanical strength of the tab 122 can be ensured and the possibility of plastic deformation of the tab 122 can be reduced. By making the maximum height t13 100 μm or less, the thickness of the tab 122 can be reduced. This increases the separation distance X11 (see FIG. 18 ) between the tabs 122 housed in the housing space 7a of the lamp 7 and reduces the possibility of the two tabs 122 coming into contact with each other. The maximum height t13 is the dimension of the tab 122 in the normal direction D13 of the first surface 120a, and is the maximum distance between the tab first surface 122a and the tab second surface 122b in the normal direction D13.

[0164] As shown in FIG. 22 , the tab 122 may include a root region 122R1, a main body region 122R2, and a tip region 122R3. The root region 122R1 is adjacent to the beam flat portion 124. The main body region 122R2 is located on the opposite side of the root region 122R1 from the beam flat portion 124. The main body region 122R2 is located between the root region 122R1 and the tip region 122R3. The tip region 122R3 is located on the opposite side of the main body region 122R2 from the beam flat portion 124. The tip region 122R3 may be semicircular in plan view. The tip of the tip region 122R3 corresponds to the tip 120p of the load beam 120. The base region 122R1 and the main body region 122R2 may be defined by a boundary at a desired position in the longitudinal direction D11. For example, the main body region 122R2 and the tip region 122R3 may be regions that overlap the lamp support portion 7b in a plan view when the tab 122 of the load beam 120 is accommodated in the accommodation space 7a of the lamp 7. The base region 122R1 may be a region that does not overlap the lamp support portion 7b in a plan view.

[0165] The central flat surface 122f may be formed in the root region 122R1, the main body region 122R2, and the tip region 122R3. The central flat surface 122f may extend in the longitudinal direction D11 and be continuously formed from the root region 122R1 to the tip region 122R3.

[0166] Next, a load beam blank plate 160 for manufacturing the above-mentioned load beam 120 will be described with reference to FIGS. 23 and 24D.

[0167] Fig. 23 is a cross-sectional view of a load beam blank plate 160 for fabricating the load beam 120. The cross-sectional view in Fig. 23 corresponds to the cross-sectional view shown in Fig. 20. The load beam blank plate 160 is in a state before the edge portion 125 is bent, and is formed by processing a plate-shaped member 160A (described later) by photolithography (wet etching) to have an overall flat shape.

[0168] The load beam blank plate 160 includes, in a plan view, a blank plate main body 161 extending in the longitudinal direction D11 in a tapered manner toward the tip of the load beam blank plate 160, and a blank plate tab 162 (see FIG. 24D ). The tip of the load beam blank plate 160 corresponds to the tip 120p of the load beam 120. The blank plate main body 161 is formed flat and corresponds to the base portion 123, the beam flat portion 124, the edge portion 125, and the hinge portion 126 described above. The beam flat portion 124 and the edge portion 125 are separated by bending the blank plate main body 161 along bending lines (not shown). The blank plate main body 161 is formed with the jig hole 127, the laser diode element opening 128, and the first piezoelectric element opening 129 described above.

[0169] The load beam blank plate 160 may be supported by a frame (not shown) surrounding the load beam blank plate 160. The load beam 120 according to this embodiment may be obtained by bending the load beam blank plate 160 while it is supported by the frame. In this case, the load beam 120 may be supported by the frame. A plurality of load beam blank plates 160 may be supported on the frame. In this case, a multi-sided load beam 120 can be produced. The multi-sided load beam 120 refers to a configuration in which a plurality of load beams 120 are supported by a single frame.

[0170] 23, the first surface 120a and the second surface 120b of the load beam blank plate 160 are each formed flat. The first surface 120a and the second surface 120b may be parallel to each other. The hinge portion 126 described above is also in a state before being folded, and is formed flat not only in the short-side direction D12 but also in the long-side direction D11.

[0171] The thickness of the load beam blank plate 160 is equal to the maximum thickness t11 of the beam flat portion 124.

[0172] As shown in Figure 24D, the first tab surface 122a and the second tab surface 122b of the blank board tab 162 are formed flat. The blank board tab 162 includes a thin-walled portion 163 (see Figure 24D). The thin-walled portion 163 is located in the center between both end portions in the short-side direction D12 and is formed in a portion corresponding to the central flat surface 122f of the tab 122. The thin-walled portion 163 is formed to be recessed from the second tab surface 122b.

[0173] The load beam 120 and the load beam blank plate 160 may be formed of plate-like members. The load beam 120 may be formed of, for example, a metal material or a stainless steel material. The stainless steel material is, for example, a metal material containing iron, chromium, and nickel as its main components. Examples of the stainless steel material include austenitic stainless steel, ferritic stainless steel, and martensitic stainless steel. Examples of the stainless steel material include SUS304, SUS301, SUS316, and SUS430.

[0174] (Method of Manufacturing Load Beam) Next, a method of manufacturing the load beam 120 according to this embodiment having the above configuration will be described with reference to Figures 24A to 24E. Figures 24A to 24E are cross-sectional views of the tab 122 of the load beam 120, and correspond to Figure 20.

[0175] First, as shown in Fig. 24A, a flat plate-like member 160A is prepared. For example, the plate-like member 160A may be a rolled material having the thickness t11 described above.

[0176] 24B, a patterned resist layer 161B is formed on the tab second surface 122b of the plate-shaped member 160A by photolithography. A resist layer 161A is formed on the entire surface of the tab first surface 122a.

[0177] Next, wet etching is used to form the outer shape of the load beam blank plate 160, as well as to form the jig hole 127, the laser diode element opening 128, and the first piezoelectric element opening 129. At this time, as shown in FIG. 24C , the tab second surface 122b of the plate-like member 160A is half-etched to form a thin-walled portion 163. The thin-walled portion 163 is formed in a portion corresponding to the central flat surface 122f of the tab 122. Half-etching refers to etching the material to be etched partway through its thickness. The depth of the thin-walled portion 163 may be, for example, 10% to 60% or 20% to 50% of the thickness t11 of the plate-like member 160A before half-etching. Thereafter, the resist layers 161A and 161B are peeled and removed.

[0178] Next, resist layers 161A and 161B are removed, thereby obtaining load beam blank plate 160 including blank plate tabs 162 as shown in Figure 24D.

[0179] Next, the blank plate body 161 of the load beam blank plate 160 is bent to form the edge portion 125 shown in FIG. 19 . Furthermore, as shown in FIG. 24E , the blank plate tab 162 is formed to form the tab 122. The forming process may be, for example, a press process using a mold. In this case, the surface opposite the thin-walled portion 163, i.e., the portion corresponding to the tab 122, is curved so that the tab first surface 122a faces inward. As a result, the inner surface of the thin-walled portion 163 forms the central flat surface 122f of the tab second surface 122b. The central flat surface 122f may be formed by the shape of a mold. Recesses 164 are formed on both sides of the central flat surface 122f in the short-side direction D12. These recesses 164 are formed by leaving both ends of the thin-walled portion 163 shown in FIG. 24D after the forming process.

[0180] This forms the tab 122 having a curved cross section. The thickness t12 of the tab 122 is thinner at the central portion 122c in the short side direction D12 than at both end portions 122d in the short side direction D12. In this way, the load beam 120 according to this embodiment is obtained.

[0181] Next, the flexure 11 (see FIG. 19) is bonded to the load beam 120 to fabricate the suspension 5. The second piezoelectric element PZ2 is previously bonded to the flexure 11. After the flexure 11 is bonded to the load beam 120, the first piezoelectric element PZ1 is placed over the first piezoelectric element opening 129 of the load beam 120, and the first piezoelectric element PZ1 is bonded to the first surface 120a of the load beam 120.

[0182] Thereafter, the magnetic head 12 is mounted on the tip of the flexure 11, and a laser diode element is attached to the magnetic head 12. When the suspension 5 is attached to the case 2 shown in FIG.

[0183] In the hard disk drive 1 thus fabricated, the magnetic disk 3 rotates at high speed. The positioning voice coil motor 6 moves the suspension 5 in the radial direction of the magnetic disk 3. This moves the magnetic head 12 to a desired position on the magnetic disk 3. When the rotation of the magnetic disk 3 stops, the suspension 5 retracts from the magnetic disk 3. At the retracted position, the tab 122 located at the tip of the load beam 120 is housed in the ramp 7.

[0184] In this embodiment, the thickness t12 of the tab 122 is thinner at the central portion 122c in the short-side direction D12 than at both end portions 122d in the short-side direction D12. This reduces the possibility of the tabs 122 of the two load beams 120 housed in the housing spaces 7a of the ramp 7 interfering with each other, as shown in FIG. 18 . That is, as shown in FIG. 18 , the thinner thickness t12 at the central portion 122c of the tab 122 increases the separation distance X11 between the two tabs 122. The separation distance X11 is the shortest distance between the two tabs 122 when viewed in the cross section shown in FIG. 18 . This reduces the possibility of the two tabs 122 housed in each housing space 7a of the ramp 7 coming into contact with each other. As a result, the possibility of foreign matter being generated in the hard disk drive 1 due to a broken tab 122 is reduced.

[0185] 18 , while the two tabs 122 are accommodated in the accommodation space 7a of the lamp 7, there is no need for the two tabs 122 to move to the retracted portion 7d while gradually narrowing the gap between them along the inclined portion 7c. This allows the gradient of the inclined portion 7c to be gentler, thereby reducing friction between the tabs 122 and the inclined surface 7e. Furthermore, because the central portion 122c of the tab 122 contacts the inclined surface 7e over a wide area, the tabs 122 are prevented from vibrating up and down while they move along the inclined portion 7c toward the retracted portion 7d, further reducing the possibility of the two tabs 122 coming into contact with each other.

[0186] Furthermore, according to this embodiment, the tab second surface 122b has two outer curved surfaces 122e and a central flat surface 122f. This allows the central flat surface 122f of the tab 122 to contact the inclined surface 7e over a wider area. Therefore, while the two tabs 122 move along the inclined portion 7c toward the retracted portion 7d, the tabs 122 are prevented from vibrating up and down, reducing the possibility of the two tabs 122 coming into contact with each other.

[0187] (Variation 6) In the above-described embodiment, an example has been described in which the tab second surface 122b has two outer curved surfaces 122e and a central flat surface 122f. However, this embodiment is not limited to this. For example, as shown in FIG. 25 , the tab second surface 122b may have two outer curved surfaces 122e and a central curved surface 122g. The central curved surface 122g is located between the two outer curved surfaces 122e. The outer curved surface 122e and the central curved surface 122g are each curved with the tab first surface 122a facing inward. The central curved surface 122g is formed in a curved shape. The central curved surface 122g is an example of a central surface. The central curved surface 122g may be formed by the shape of a mold. In a cross section perpendicular to the longitudinal direction D11, the outer curved surface 122e and the central curved surface 122g may each have an arc shape. In a cross section perpendicular to the longitudinal direction D11, the radius of curvature Rd of the central curved surface 122g may be 100 μm or more and 200 μm or less, or 100 μm or more and 150 μm or less. The radius of curvature Rd of the central curved surface 122g is greater than the radius of curvature Rc of the outer curved surface 122e (Rd > Rc). The central portion 122c is located on the central curved surface 122g. In the example shown in FIG. 25, the central portion 122c is located on the central curved surface 122g, and the central curved surface 122g is formed so as to straddle the central portion 122c. The radius of curvature Rd may vary discontinuously from the outer curved surface 122e to the central curved surface 122g. In this case, the central curved surface 122g may be formed discontinuously with the outer curved surface 122e.

[0188] (Variation 7) In the present embodiment described above, an example has been described in which the thin-walled portion 163 is formed in the plate-shaped member 160A, and then the portion of the plate-shaped member 160A corresponding to the tab 122 is curved. However, this embodiment is not limited to this. For example, as shown in Figures 26A to 26C, the portion of the plate-shaped member 160A corresponding to the tab 122 may first be curved, and then the portion of the tab second surface 122b corresponding to the central portion 122c may be flattened to form the central flat surface 122f.

[0189] In this case, first, as shown in FIG. 26A, a flat plate-like member 160A is prepared.

[0190] Next, as shown in Fig. 26B, the portion of plate-like member 160A corresponding to tab 122 is molded. The molding may be, for example, a press process using a mold. In this case, the portion corresponding to tab 122 is curved so that tab first surface 122a faces inward. This forms tab 122 having an overall curved cross-sectional shape.

[0191] Next, as shown in FIG. 26C , the tab second surface 122b of the plate-shaped member 160A is formed. For example, the forming process may be a press process using a mold different from the mold used in the forming process shown in FIG. 26B . This thins the area including the central portion 122c of the tab second surface 122b. Specifically, the area including the central portion 122c of the tab second surface 122b may be flattened to form a central flat surface 122f on the tab second surface 122b. The central flat surface 122f may be formed by the shape of the mold. At this time, the thickness t12 of the tab 122 is thinner at the central portion 122c in the short-side direction D12 than at both end portions 122d in the short-side direction D12. In this manner, the load beam 120 according to this embodiment is obtained.

[0192] (Variation 8) In the present embodiment described above, an example has been described in which the step of forming the thin-walled portion 163 is performed after the step of forming the tab 122 into a curved shape. However, the present embodiment is not limited to this. For example, the step of forming the thin-walled portion 163 may be performed simultaneously with the step of forming the tab 122 into a curved shape. In other words, the step of forming the tab 122 into a curved shape and the step of forming the thin-walled portion 163 may be performed simultaneously. In this case, the mold may be configured so that it can form the tab 122 into a curved shape and also form the thin-walled portion 163.

[0193] Third Embodiment Next, a load beam and a load beam blank plate according to a third embodiment of the present disclosure will be described with reference to FIGS.

[0194] The third embodiment shown in Figures 27 to 37 differs mainly in that the edge portion includes a curved edge portion that is located closer to the tab than the inclined edge portion. Other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 16. In Figures 27 to 37, the same parts as those of the first embodiment shown in Figures 1 to 16 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0195] In recent hard disk drives, the number of magnetic disks, also called platters, has been increased in order to increase the recording capacity.

[0196] However, as the number of magnetic disks increases, the magnetic disks move closer to each other. In this case, the internal airflow generated inside the case when the magnetic disks rotate may become turbulent, potentially causing an airflow to flow in from the tip of the suspension to the base. This may cause the flying attitude of the magnetic head to change. This may result in a decrease in the positioning accuracy of the magnetic head relative to the magnetic disks.

[0197] An object of the present disclosure is to provide a load beam and a load beam blank plate that can reduce changes in the flying attitude of a magnetic head.

[0198] The present embodiment will be described below.

[0199] First, a load beam and a load beam blank plate according to the third embodiment of the present disclosure will be described with reference to Figures 27 to 37. First, a hard disk drive 1 using a suspension 5 including a load beam 220 according to this embodiment will be described with reference to Figure 27.

[0200] As shown in FIG. 27 , the hard disk drive 1 includes a case 2, a magnetic disk 3, a spindle motor 4, a suspension 5, a voice coil motor 6, and a ramp 7. The magnetic disk 3 is configured to store data. The magnetic disk 3 is rotatably attached to the case 2 and is configured to be rotated by the spindle motor 4. The suspension 5 includes a flexure and a load beam 220. A magnetic head (not shown) is mounted on the tip of the flexure. The magnetic head is configured to write and read data to and from the magnetic disk 3. The load beam 220 supports the magnetic head and the tip of the flexure so that the magnetic head maintains a desired flying height relative to the magnetic disk 3 when writing and reading data. The suspension 5 is rotated by the voice coil motor 6, allowing the magnetic head to be moved to a desired position on the magnetic disk 3.

[0201] 27 includes a plurality of magnetic disks 3 and a plurality of suspensions 5 in order to improve recording density. The hard disk drive 1 is configured so that the magnetic heads of the suspensions 5 write and read data to and from the upper and lower surfaces of each of the magnetic disks 3.

[0202] The ramp 7 is located near the magnetic disk 3 inside the case 2. When the magnetic disk 3 stops rotating, the multiple suspensions 5 retract together from the magnetic disk 3. At the retracted position, a tab 222 (see FIG. 29 , described later) located at the tip 220p of the load beam 220 is accommodated in the ramp 7. The ramp 7 is configured to support the tab 222. More specifically, as shown in FIG. 28 , the ramp 7 includes multiple ramp support portions 7b, and an accommodation space 7a for accommodating the tab 222 is defined between two adjacent ramp support portions 7b. The tab 222 accommodated in the accommodation space 7a is supported in contact with the ramp support portions 7b.

[0203] Two tabs 222 are accommodated in one accommodation space 7a. Each tab 222 is supported by the opposing lamp support portion 7b. At this time, the two tabs 222 are pressed in a direction toward each other.

[0204] Next, the load beam 220 according to this embodiment will be described.

[0205] As shown in FIG. 29 , the load beam 220 is configured to support the magnetic head and the flexure. The magnetic head is mounted on the tip of the flexure. The load beam 220 has a central axis CL along a first direction D21. In a plan view, the first direction D21 is a direction from the base of the load beam 220 toward the tip 220p. The base of the load beam 220 corresponds to the lower part of the load beam 220 in FIG. 29 , and the tip 220p of the load beam 220 corresponds to the upper part of the load beam 220 in FIG. 29 . In a plan view, a direction perpendicular to the first direction D21 is defined as a second direction D22. The plan view refers to the case where the load beam 220 is viewed in the normal direction of a first surface 221a of a beam flat portion 224 (described later).

[0206] 29, the load beam 220 includes a beam body 221 that extends in the first direction D21 and tapers toward a tip 220p of the load beam 220, and a tab 222 that is located at the tip 220p of the load beam 220. The tab 222 extends in the first direction D21 from the beam body 221 to the tip 220p.

[0207] As shown in Fig. 30 , the beam main body 221 includes a first surface 221a and a second surface 221b located on the opposite side to the first surface 221a. The first surface 221a corresponds to the upper surface in Fig. 30 , and the second surface 221b corresponds to the lower surface in Fig. 30 . The first surface 221a and the second surface 221b are each formed from a beam flat portion 224 to an edge portion 225, which will be described later.

[0208] 29 , the beam main body 221 may include a base portion 223, a beam flat portion 224, a pair of edge portions 225, and a hinge portion 226. The base portion 223, the beam flat portion 224, the edge portions 225, and the hinge portion 226 are formed from the first surface 221 a to the second surface 221 b.

[0209] The base portion 223 is located at the base of the load beam 220. A base plate (not shown) is joined to a first surface 221a of the base portion 223. The base portion 223 may include a pair of side edges 223a. The side edges 223a may extend along the first direction D21. A piezoelectric element opening 229 for mounting a piezoelectric element (not shown) may be formed in the base portion 223. However, the piezoelectric element opening 229 does not have to be formed in the base portion 223.

[0210] The beam flat portion 224 may be located closer to the tip 220p of the load beam 220 than the base portion 223. The beam flat portion 224 may extend in the first direction D21. The beam flat portion 224 may extend in a tapered shape toward the tab 222. The beam flat portion 224 may be formed in a flat shape. The beam flat portion 224 is not limited to being formed in a strictly flat shape, and is a portion that does not include an intentionally bent portion such as the edge portion 225.

[0211] The beam flat portion 224 according to this embodiment may include a pair of curved shoulders 224a. The curved shoulders 224a may be adjacent to an edge curved portion 231, which will be described later. The outer edge of the curved shoulders 224a may be curved in the same manner as the edge curved portion 231. The beam flat portion 224 includes the curved shoulders 224a, thereby forming the edge curved portion 231.

[0212] A jig hole 227 may be formed in the beam flat portion 224. The jig hole 227 may be located closer to the tip 220p of the load beam 220 than a hinge portion 226 (described later) is. The jig hole 227 may be located on the opposite side of a laser diode element opening 228 (described later) from the tip 220p of the load beam 220. The jig hole 227 may extend from the first surface 221a to the second surface 221b of the beam main body 221, or may penetrate the beam main body 221.

[0213] A laser diode element opening 228 for accommodating a laser diode element (not shown), which will be described later, may be formed in the beam flat portion 224. The laser diode element opening 228 may be located closer to the tip 220p of the load beam 220 than the jig hole 227. The laser diode element opening 228 may extend from the first surface 221a to the second surface 221b of the beam main body 221, or may penetrate the beam main body 221. The laser diode element is attached to the magnetic head so as to penetrate through the laser diode element opening 228.

[0214] 29 and 30 , the edge portions 225 may be located on both sides of the beam flat portion 224 in the second direction D22 in a plan view. The edge portions 225 may be portions that are bent with respect to the beam flat portion 224. The edge portions 225 may have a bent shape with the first surface 221 a facing inward.

[0215] As shown in FIG. 29 , the hinge portion 226 may be located between the base portion 223 and the beam flat portion 224. The hinge portion 226 may connect the base portion 223 and the beam flat portion 224. The hinge portion 226 may be bent with the second surface 221b facing inward so that the magnetic head approaches the magnetic disk 3. The hinge portion 226 may be formed to have low bending rigidity. More specifically, the hinge portion 226 may include a pair of hinge beams 226a, and the base portion 223 and the beam flat portion 224 may be connected by the pair of hinge beams 226a. The pair of hinge beams 226a may be spaced apart from each other in the second direction D22, and an opening may be formed between the pair of hinge beams 226a. In this case, when the beam flat portion 224 is affected by the airflow generated by the rotation of the magnetic disk 3, the hinge portion 226 elastically deforms, allowing the magnetic head to maintain a desired flying height relative to the magnetic disk 3. A bending curve (not shown) of the hinge portion 226 may be along the second direction D22, or the hinge portion 226 may be formed flat along the second direction D22.

[0216] 29 , the tab 222 may extend in an elongated shape in the first direction D21 from the beam flat portion 224 of the beam main body 221 to the tip 220p of the load beam 220. The tip of the tab 222 may constitute the tip 220p of the load beam 220. When the suspension 5 is retracted onto the ramp 7, the tab 222 is supported by the ramp support portion 7b of the ramp 7. The tab 222 may have a curved shape with the first surface 221a facing inward in a cross section perpendicular to the first direction D21.

[0217] As shown in FIG. 30 , the thickness t21 of the beam flat portion 224 may be, for example, 25.0 μm or more and 35.0 μm or less. Setting the thickness t21 to 25.0 μm or more ensures the mechanical strength of the load beam 220 and reduces the possibility of plastic deformation of the load beam 220. Setting the thickness t21 to 35.0 μm or less reduces the thickness of the load beam 220. This reduces the thickness of the suspension 5, contributing to a reduction in the thickness of the hard disk drive 1. For example, the thickness t21 may be 25.0 μm or more and 30.0 μm or less, 27.0 μm or more and 30.0 μm or less, or 29.0 μm or more and 30.0 μm or less. The thickness t21 is the dimension of the beam flat portion 224 in the normal direction of the first surface 221 a and is the distance between the first surface 221 a and the second surface 221 b of the beam flat portion 224.

[0218] As shown in FIGS. 29 and 31, the edge portion 225 of the load beam 220 according to this embodiment may include an inclined edge portion 230 and a curved edge portion 231.

[0219] The edge inclined portion 230 extends in a direction inclined with respect to the first direction D21 in a plan view. The edge inclined portion 230 may extend linearly. In the example shown in Fig. 29 , the edge inclined portion 230 may extend from an end of the beam flattened portion 224 close to the hinge portion 226 to the edge curved portion 231.

[0220] 30 and 31 , the edge inclined portion 230 includes an edge inclined end surface 232. The edge inclined end surface 232 is connected to the first surface 221a and the second surface 221b. The edge inclined end surface 232 may extend in a direction inclined with respect to the first direction D21. The edge inclined end surface 232 may also extend linearly. The edge inclined end surface 232 corresponds to a blank plate inclined end surface 263 of a blank plate main body 261, which will be described later.

[0221] 29 and 31 , the edge curved portion 231 is located closer to the tab 222 than the edge inclined portion 230. The edge curved portion 231 is located at the tip end of the beam main body 221. The edge curved portion 231 may be connected to the tab 222. The edge curved portion 231 is formed continuously from the edge inclined portion 230, and is formed in a curved shape that is convex outward from the beam main body 221 in a plan view.

[0222] As shown in FIGS. 31 and 32 , the edge curved portion 231 includes a curved edge end surface 233. The curved edge end surface 233 is connected to the first surface 221 a and the second surface 221 b. The curved edge end surface 233 may be curved in a plan view. The curved edge end surface 233 may be formed continuously from the inclined edge end surface 232. The curved edge end surface 233 may be curved so as to be convex outward from the beam main body 221 in a plan view. The curved edge end surface 233 shown on the right side in FIG. 31 is curved in the edge curved portion 231 so as to be convex toward the upper right of the beam main body 221. The curved edge end surface 233 shown on the left side in FIG. 31 is curved in the edge curved portion 231 so as to be convex toward the upper left of the beam main body 221.

[0223] As shown in FIG. 32 , the curved edge end surface 233 may be linear in cross-sectional view (described below). The curved edge end surface 233 may be perpendicular to the first surface 221a and the second surface 221b. The corner where the curved edge end surface 233 intersects with the first surface 221a may be rounded. The corner where the curved edge end surface 233 intersects with the second surface 221b may be rounded. This reduces the possibility of the curved edge end surface 233 getting caught on other components and damaging them. However, although not shown, the curved edge end surface 233 may be inclined toward the first surface 221a and the second surface 221b in cross-sectional view. Alternatively, the curved edge end surface 233 may include two curved surfaces. One of the curved surfaces may be formed by etching the first surface 221a and connected to the first surface 221a. The corner where this curved surface intersects with the first surface 221a may be rounded. The other curved surface may be formed by etching the second surface 221b and connected to the second surface 221b. The corner where this curved surface intersects with the second surface 221b may be rounded. When the edge curved end surface 233 includes two curved surfaces, turbulence of the airflow flowing into the tip 220p of the load beam 220 can be reduced, and the pressure that the tip region of the load beam 220 receives from the airflow can be reduced. The shape of the above-mentioned edge inclined end surface 232 in a cross-sectional view is also similar to that of the edge curved end surface 233.

[0224] The edge curved portion 231 may include an edge curved surface 234 constituting the second surface 221b described above. The edge curved surface 234 may be formed in a curved shape. The edge curved surface 234 may form a surface continuous with the second surface 221b of the edge inclined portion 230. The edge curved surface 234 according to this embodiment may have a curved shape as shown in FIG. 31 in a plan view. The edge curved surface 234 may not have a curved shape in a cross-sectional view, but may have a linear shape as shown in FIG. 32. However, the edge curved surface 234 may also have a curved shape in a cross-sectional view. A cross-sectional view refers to a cross-section perpendicular to the central axis CL. The cross-section shown in FIG. 32 is a cross-section passing through the edge curved portion 231.

[0225] The curved edge portion 231 may be formed in an arc shape in a plan view. In this case, the curved edge end surface 233 and the curved edge surface 234 may also be formed in an arc shape in a plan view. The radius R of the curved edge portion 231 in a plan view may be 0.8 mm or more and 1.8 mm or less. The radius R is the radius of the outer edge of the curved edge portion 231 in a plan view. By setting the radius R to 0.8 mm or more, the pressure received from the airflow (see symbol F in FIG. 27 ) flowing in from the tip 220p can be effectively reduced. By setting the radius R to 1.8 mm or less, the planar area of ​​the beam main body 221 can be reduced, thereby reducing the possibility of an increase in the pressure received by the airflow on the second surface 221b of the beam main body 221. The outer edge of the curved edge portion 231 is the edge where the curved edge end surface 233 and the curved edge surface 234 constituting the second surface 221b intersect.

[0226] The curved edge portion 231 may be formed into an elliptical arc shape in a planar view. In this case, the curved edge end surface 233 and the curved edge surface 234 may also be formed into an elliptical arc shape in a planar view. The maximum radius of the curved edge portion 231 in a planar view may be 0.8 mm or more and 1.8 mm or less. The maximum radius is the radius of the outer edge of the curved edge portion 231 in a planar view. By setting the maximum radius to 0.8 mm or more, the pressure received from the airflow (see symbol F in FIG. 27 ) flowing in from the tip 220p can be effectively reduced. By setting the maximum radius to 1.8 mm or less, the planar area of ​​the beam main body 221 can be reduced, thereby reducing the possibility of an increase in the pressure received by the airflow on the second surface 221b of the beam main body 221. The outer edge of the curved edge portion 231 may have a shape of a portion of a desired elliptical shape in a planar view. The major radius of the ellipse formed by the outer edge of the curved edge portion 231 may be 0.8 mm or more and 1.8 mm or less. The flattening ratio of the ellipse formed by the outer edge of the edge curved portion 231 may be a value greater than 0.0 and less than 1.0. The planar shape of the outer edge of the edge curved portion 231 may be formed by a portion of the ellipse defined by the major axis and the flattening ratio. The flattening ratio is the value obtained by dividing the minor axis by the major axis. The flattening ratio may be, for example, 0.25 or greater and 0.70 or less.

[0227] The edge portion 225 according to the present embodiment is formed by bending the beam flat portion 224 along a bend line 225L (see FIG. 34 ). The bend line 225L may include a bend line inclined portion 225La extending in a direction inclined with respect to the first direction D21 in a plan view, and a bend line curved portion 225Lb formed in a curved shape in a plan view. The bend line curved portion 225Lb may be formed in a curved shape so as to form the edge curved portion 231.

[0228] The surface roughness of the curved edge end surface 233 may be rougher than the surface roughness of the second surface 221b of the beam body 221. The surface roughness may be measured in ten-point average roughness Rz (JIS).

[0229] The difference between the ten-point mean roughness RzJIS of the curved edge end surface 233 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.100 μm or more, or 0.150 μm or more. The difference between the ten-point mean roughness RzJIS of the curved edge end surface 233 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.350 μm or less, or 0.300 μm or less. The difference between the ten-point mean roughness RzJIS of the curved edge end surface 233 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.100 μm or more and 0.350 μm or less, 0.100 μm or more and 0.300 μm or less, 0.150 μm or more and 0.350 μm or less, or 0.150 μm or more and 0.300 μm or less.

[0230] By making the difference between the ten-point mean roughness RzJIS of the curved edge end surface 233 and the ten-point mean roughness RzJIS of the second surface 221b 0.100 μm or more, it is possible to reduce airflow separation downstream of the curved edge end surface 233. By making the difference between the ten-point mean roughness RzJIS of the curved edge end surface 233 and the ten-point mean roughness RzJIS of the second surface 221b 0.350 μm or less, it is possible to reduce the possibility of foreign matter being generated from the curved edge end surface 233. The ten-point mean roughness RzJIS conforms to JIS B 0601:2013. More specifically, the ten-point mean roughness RzJIS is the difference between the average height of the top five peaks in order from the highest peak and the average depth of the bottom five valleys in order from the deepest valley on a roughness curve having a reference length LS.

[0231] The surface roughness of the inclined edge end face 232 may be rougher than the surface roughness of the second surface 221b. As with the curved edge end face 233, the difference between the ten-point mean roughness RzJIS of the inclined edge end face 232 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.100 μm or more, or 0.150 μm or more. The difference between the ten-point mean roughness RzJIS of the inclined edge end face 232 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.350 μm or less, or 0.300 μm or less. The difference between the ten-point average roughness RzJIS of the edge inclined end surface 232 and the ten-point average roughness RzJIS of the second surface 221b may be 0.100 μm or more and 0.350 μm or less, 0.100 μm or more and 0.300 μm or less, 0.150 μm or more and 0.350 μm or less, or 0.150 μm or more and 0.300 μm or less.

[0232] A method for measuring the ten-point average roughness RzJIS will be described below. While a method for measuring the ten-point average roughness RzJIS of the curved edge end face 233 will be described below as a representative example, the method for measuring the ten-point average roughness RzJIS of the inclined edge end face 232 is similar.

[0233] First, as shown in Figure 31, a cross-sectional line L1 is defined that is perpendicular to the outer edge of the curved edge portion 231 and perpendicular to the curved edge end face 233, and a cross-section including this cross-sectional line L1 is created. As long as the cross-sectional line L1 is perpendicular to the outer edge of the curved edge portion 231, the direction along which the cross-sectional line L1 runs is arbitrary. This is because it is believed that the surface roughness does not depend on the position of the cross-sectional line L1. The cross-sectional line L1 and the inner edge of the curved edge end face 233 intersect at an intersection point P1, and the cross-sectional line L1 and the outer edge of the curved edge end face 233 intersect at an intersection point P2. The outer edge of the curved edge end face 233 corresponds to the outer edge of the curved edge portion 231. In a plan view, the intersection point P1 is located inside the intersection point P2.

[0234] A cross section along the cross-sectional line L1 is shown in Figure 32. When viewed from the cross section shown in Figure 32, the ten-point average roughness RzJIS of a region Q1 located near the intersection point P1 of the edge curved end face 233 and the ten-point average roughness RzJIS of a region Q2 located near the intersection point P2 are calculated. As a representative example, an enlarged view of region Q1 is shown in Figure 33.

[0235] As shown in Fig. 33, region Q1 is a region spanning a predetermined reference length LS. The aforementioned reference length LS is 4 µm. As shown in Fig. 32, region Q1 is a region 5 µm away from intersection point P1. A roughness curve with a reference length LS of 4 µm is set from a point 5 µm away from intersection point P1, and the aforementioned surface roughness is measured.

[0236] In the example shown in Fig. 33, the peaks having the heights from the highest peak to the fifth highest peak on the roughness curve are indicated by PH, and the valleys having the depths from the deepest valley to the fifth deepest valley on the roughness curve are indicated by PL. The difference between the average height of the five peaks PH and the average depth of the five valley bottoms PL is the ten-point average roughness RzJIS.

[0237] More specifically, the cross section of the target is observed using a scanning electron microscope. The observation conditions for the scanning electron microscope are as follows: Observation magnification: 20,000 times (the observation magnification standard when photographing is Polaroid 545); Acceleration voltage: 15 kV; Working distance: 15 mm; Sample tilt angle: 70 degrees.

[0238] Under observation with a scanning electron microscope, the ten-point average roughness RzJIS of the curved edge end surface 233 is calculated as described above for the cross section of the target.

[0239] The ten-point average roughness RzJIS of the region Q1 and the ten-point average roughness RzJIS of the region Q2 shown in Fig. 32 are calculated. The average of these two ten-point average roughness RzJIS values ​​is set as the ten-point average roughness RzJIS of the edge curved end surface 233.

[0240] The ten-point average roughness RzJIS of the second surface 221b can be calculated by setting a reference length LS in an arbitrary direction at an arbitrary position on the second surface 221b.

[0241] The surface roughness is not limited to the ten-point average roughness Rz (JIS), but may be the arithmetic average roughness Ra.

[0242] The difference between the arithmetic mean roughness Ra of the curved edge end surface 233 and the arithmetic mean roughness Ra of the second surface 221b may be 0.030 μm or more and 0.100 μm or less. By making the difference between the arithmetic mean roughness Ra of the curved edge end surface 233 and the arithmetic mean roughness Ra of the second surface 221b 0.030 μm or more, the curved edge end surface 233 can effectively receive the pressure of the airflow. By making the difference between the arithmetic mean roughness Ra of the curved edge end surface 233 and the arithmetic mean roughness Ra of the second surface 221b 0.100 μm or less, the possibility of foreign matter being generated from the curved edge end surface 233 can be reduced. The arithmetic mean roughness Ra is calculated in accordance with the provisions of JIS B 0601:2013 for each of the regions Q1 and Q2 shown in FIG. 32 . The average value of the arithmetic mean roughness Ra in the region Q1 and the arithmetic mean roughness Ra in the region Q2 is defined as the arithmetic mean roughness Ra of the curved edge end surface 233.

[0243] The difference between the arithmetic mean roughness Ra of the inclined edge end surface 232 and the arithmetic mean roughness Ra of the second surface 221b may be 0.030 μm or more and 0.100 μm or less. By making the difference between the arithmetic mean roughness Ra of the inclined edge end surface 232 and the arithmetic mean roughness Ra of the second surface 221b 0.030 μm or more, the inclined edge end surface 232 can effectively receive the pressure of the airflow. By making the difference between the arithmetic mean roughness Ra of the inclined edge end surface 232 and the arithmetic mean roughness Ra of the second surface 221b 0.100 μm or less, the possibility of foreign matter being generated from the inclined edge end surface 232 can be reduced. The arithmetic mean roughness Ra of the inclined edge end surface 232 is calculated in the same way as the arithmetic mean roughness Ra of the curved edge end surface 233.

[0244] The arithmetic mean roughness Ra of the second surface 221b can be calculated by setting a reference length LS in an arbitrary direction at an arbitrary position on the second surface 221b.

[0245] A method for preparing a cross section of the observation object shown in Fig. 32 will be described below. A method for preparing a cross section for measuring the surface roughness of the curved edge end face 233 will be described below, but cross sections of the observation object for measuring the surface roughness of the inclined edge end face 232 and the second surface 221b can also be prepared in a similar manner.

[0246] First, a trimming razor is used to cut out a portion of the edge portion 225 of the beam body 221, including the curved edge end surface 233, as a test piece. The size of the test piece is set arbitrarily in consideration of ease of handling.

[0247] Next, the test pieces are sealed with resin. Epoxy resin is used as the resin. The resin covers the entire test piece. The thickness of the resin applied to each test piece is 1 mm.

[0248] Next, a trimming razor is used to cut the test piece together with the resin along the cross-sectional straight line L1 and along a direction perpendicular to the edge curved end surface 233. This allows the cross section along the cross-sectional straight line L1 to be exposed from the resin. The cross section obtained at this time takes into consideration the cutting allowance in the procedure described below.

[0249] Next, the exposed cross section is trimmed from the resin using a microtome. In this trimming, the resin sealing the test specimen is removed by 1 mm in a direction perpendicular to the cross section of the test specimen, in order to reduce mechanical strain on the cross section of the test specimen.

[0250] Next, using an ion milling device, a broad argon ion beam is irradiated in a direction perpendicular to the cross section of the test piece. More specifically, a shielding plate is placed on the test piece so that the cross section is exposed, and accelerated argon ions are irradiated onto the cross section of the test piece to process the cross section. The ion beam irradiation continues at 5 kV for 8 hours, and the test piece is milled by 100 μm to 200 μm in a direction perpendicular to the cross section. In this way, the cross section of the object to be observed is obtained.

[0251] Next, a load beam blank plate 260 for manufacturing the above-mentioned load beam 220 will be described with reference to FIGS.

[0252] Fig. 34 shows an enlarged plan view of a portion of the load beam blank plate 260. Fig. 35 shows a cross-sectional view of the load beam blank plate 260. The cross-sectional view of Fig. 35 corresponds to the cross-sectional view shown in Fig. 30. The load beam blank plate 260 corresponds to the load beam 220 before the edge portion 225 is bent, and is formed flat overall.

[0253] 34 , the load beam blank plate 260 may include, in a plan view, a blank plate main body 261 extending in the first direction D21 in a tapered shape toward the tip of the load beam blank plate 260, and a blank plate tab 262. The tip of the load beam blank plate 260 may correspond to the tip 220p of the load beam 220. The blank plate main body 261 may correspond to the beam main body 221 described above. The beam flat portion 224 and the edge portion 225 may be separated by bending the blank plate main body 261 along a bending line 225L. The blank plate main body 261 may be formed with the jig hole 227 and the laser diode element opening 228 described above.

[0254] As shown in Fig. 35 , the blank plate main body 261 includes a first surface 221a and a second surface 221b. In the load beam blank plate 260, as shown in Fig. 35 , the first surface 221a and the second surface 221b may each be formed flat. The first surface 221a and the second surface 221b may be parallel to each other. The above-mentioned hinge portion 226 is also in a state before being folded, and may be formed flat not only in the second direction D22 but also in the first direction D21.

[0255] The blank plate body 261 may include a pair of blank plate inclined end surfaces 263 and a pair of blank plate curved end surfaces 264 .

[0256] The blank plate inclined end surface 263 is connected to the first surface 221a and the second surface 221b. The blank plate inclined end surface 263 may extend in a direction inclined with respect to the first direction D21 in a plan view. The blank plate inclined end surface 263 may extend linearly. The blank plate inclined end surface 263 corresponds to the edge inclined end surface 232 of the edge inclined portion 230 described above.

[0257] The blank plate curved end surface 264 is connected to the first surface 221a and the second surface 221b. The blank plate curved end surface 264 is located closer to the blank plate tab 262 than the blank plate inclined end surface 263. The blank plate curved end surface 264 is formed continuously from the corresponding blank plate inclined end surface 263 and is curved so as to be convex toward the outside of the blank plate main body 261 in a plan view. The blank plate curved end surface 264 corresponds to the edge curved end surface 233.

[0258] The surface roughness of the blank plate curved end surface 264 may be rougher than the surface roughness of the second surface 221b of the blank plate body 261, similar to the edge curved end surface 233 described above. The difference between the ten-point mean roughness RzJIS of the blank plate curved end surface 264 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.100 μm or more, or 0.150 μm or more. The difference between the ten-point mean roughness RzJIS of the blank plate curved end surface 264 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.350 μm or less, or 0.300 μm or less. The difference between the ten-point average roughness RzJIS of the blank plate curved end surface 264 and the ten-point average roughness RzJIS of the second surface 221b may be 0.100 μm or more and 0.350 μm or less, 0.100 μm or more and 0.300 μm or less, 0.150 μm or more and 0.350 μm or less, or 0.150 μm or more and 0.300 μm or less.

[0259] The surface roughness of the blank plate curved end surface 264 can be measured in the same way as the surface roughness of the edge curved end surface 233 by defining a cross-sectional straight line L1 that is perpendicular to the blank plate curved end surface 264 and also perpendicular to the second surface 221b.

[0260] The surface roughness of the blank plate inclined end face 263 may also be rougher than the surface roughness of the second surface 221b of the blank plate body 261. As with the blank plate curved end face 264, the difference between the ten-point mean roughness RzJIS of the blank plate inclined end face 263 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.100 μm or more, or 0.150 μm or more. The difference between the ten-point mean roughness RzJIS of the blank plate inclined end face 263 and the ten-point mean roughness RzJIS of the second surface 221b may be 0.350 μm or less, or 0.300 μm or less. The difference between the ten-point average roughness RzJIS of the blank plate inclined end face 263 and the ten-point average roughness RzJIS of the second surface 221b may be 0.100 μm or more and 0.350 μm or less, 0.100 μm or more and 0.300 μm or less, 0.150 μm or more and 0.350 μm or less, or 0.150 μm or more and 0.300 μm or less.

[0261] The blank plate tab 262 is in a state before the above-described tab 222 is formed. The blank plate tab 262 is located at the tip of the load beam blank plate 260. The blank plate tab 262 may extend in an elongated shape in the first direction D21 from the blank plate main body 261 to the tip of the load beam blank plate 260. The blank plate tab 262 may be formed in a flat shape or may be continuous with the blank plate main body 261.

[0262] The thickness of the blank plate body 261 may be equal to the thickness t21 of the beam flat portion 224.

[0263] The blank plate body 261 may be supported by a frame (not shown) that surrounds the blank plate body 261. The load beam 220 according to this embodiment may be obtained by bending the blank plate body 261 while it is supported by the frame. In this case, the load beam 220 may be supported by the frame. A plurality of blank plate bodies 261 may be supported on the frame. In this case, a multi-sided load beam 220 can be produced. The multi-sided load beam 220 refers to a configuration in which a plurality of load beams 220 are supported by a single frame.

[0264] Next, a method for manufacturing the load beam 220 according to this embodiment having the above-described configuration will be described.

[0265] First, a flat plate-like member is prepared. For example, the plate-like member may be a rolled material having the thickness t21 described above.

[0266] Next, a patterned resist layer (not shown) is formed by photolithography, and the plate-like member is etched to form the load beam blank plate 260 shown in FIGS. 34 and 35 . More specifically, the outer shape of the load beam blank plate 260 is formed, and the above-mentioned blank plate inclined end face 263 and blank plate curved end face 264 are formed. A jig hole 227, a laser diode element opening 228, and a piezoelectric element opening 229 are formed in the blank plate body 261. The blank plate inclined end face 263 and blank plate curved end face 264 may then be roughened. For example, the plate-like member may be immersed in an electrolyte with a sulfuric acid concentration of 12% with the resist layer remaining, and an electric current may be passed through to perform the etching process. In this case, for example, the temperature of the electrolyte is adjusted to 30°C, and the current density is set to 50 A / m. ２ ~150 A / m ２ This allows the surface roughness of the blank plate inclined end surface 263 and the blank plate curved end surface 264 to be rougher than the surface roughness of the second surface 221b of the beam body 221. When roughening the blank plate inclined end surface 263 and the blank plate curved end surface 264, a resist layer may be formed on the wall surface (not shown) of the jig hole 227 or the like to prevent the surface from being roughened. The blank plate inclined end surface 263 and the blank plate curved end surface 264 may be roughened when the outer shape of the load beam blank plate 260 is formed by etching.

[0267] Next, the blank plate body 261 of the load beam blank plate 260 is bent. This forms the edge portion 225 as shown in FIGS. 29 and 30 . More specifically, the blank plate body 261 is bent along the fold line 225L shown in FIG. 34 . The edge inclined portion 230 is formed along the fold line inclined portion 225La, and the blank plate inclined end surface 263 becomes the edge inclined end surface 232. The edge curved portion 231 is formed along the fold line curved portion 225Lb, and the blank plate curved end surface 264 becomes the edge curved end surface 233. Furthermore, a portion of the blank plate body 261 corresponding to the hinge portion 226 is bent to form the hinge portion 226. The blank plate tab 262 is also formed into a curved shape to form the tab 222.

[0268] In this manner, the load beam 220 according to this embodiment is obtained.

[0269] A flexure (not shown) is bonded to the load beam 220 to form the suspension 5. Then, a magnetic head is mounted on the tip of the flexure, and a laser diode element is attached to the magnetic head. The laser diode element is attached to the magnetic head so as to pass through the laser diode element opening 228.

[0270] Then, the suspension 5 is attached to the case 2 shown in FIG. 27, and the hard disk drive 1 is obtained.

[0271] In recent hard disk drives, the number of magnetic disks 3 housed in the case 2 has been increasing, as shown in FIG. 36 , in order to increase storage capacity. In this case, the distance between the magnetic disks 3 is shortened. This may cause turbulence in the internal airflow generated when the magnetic disks 3 rotate, potentially resulting in an airflow (see symbol F in FIG. 27 ) flowing in from the tip of the suspension 5. Furthermore, the distance X21 between the uppermost magnetic disk 3 of the multiple magnetic disks 3 and the upper part 2 a of the case 2 is also shortened. In the space indicated by the distance X21, the airflow is likely to be turbulent due to the influence of the case 2, increasing the possibility of an airflow (see symbol F in FIG. 27 ) flowing in from the tip of the suspension 5. The distance X22 between the lowest magnetic disk 3 and the lower part 2 b of the case 2 is also shortened, increasing the possibility of a similar airflow flowing in from the tip of the suspension 5.

[0272] As shown in Figure 37, the airflow that flows in from the tip of the load beam 220 passes around the tab 222 and reaches the tip of the beam main body 221. The tip of the beam main body 221 is formed with a curved edge portion 231 of the edge portion 225. As a result, as shown by the solid arrow in Figure 37, the airflow flows along the curved shape of the curved edge portion 231. Therefore, the pressure that the load beam 220 receives from the airflow can be gradually changed as the airflow flows, and the pressure that the load beam 220 receives from the airflow can be reduced.

[0273] A portion of the airflow that reaches the tip of the beam main body 221 passes near the curved edge end surface 233, as indicated by the dashed arrow in Figure 37. As described above, the surface roughness of the curved edge end surface 233 is greater than the surface roughness of the second surface 221b, which reduces separation of the airflow downstream of the curved edge end surface 233. This reduces fluctuations in the pressure that the suspension 5 receives from the airflow, thereby stabilizing the floating attitude of the suspension 5. In this embodiment, the surface roughness of the inclined edge end surface 232 is also greater than the surface roughness of the second surface 221b. This reduces fluctuations in the pressure that the suspension 5 receives from the airflow passing near the inclined edge end surface 232.

[0274] 36, the load beam 220 according to this embodiment is effective when used in the suspension 5 located between the uppermost magnetic disk 3 and the case 2, and is effective when used in the suspension 5 located between the lowermost magnetic disk 3 and the case 2. However, the load beam 220 according to this embodiment may also be used in the suspension 5 located between the magnetic disks 3.

[0275] When a laser diode element is mounted on the suspension 5, the weight of the tip of the suspension 5 increases, making the floating attitude of the magnetic head more susceptible to fluctuations due to the influence of air currents. However, as described above, the load beam 220 according to this embodiment can reduce the pressure from air currents, thereby effectively maintaining the floating attitude of the magnetic head.

[0276] As described above, according to this embodiment, the edge portion 225 bent from the beam flat portion 224 includes the edge inclined portion 230 extending in a direction inclined with respect to the first direction D21 in a plan view, and the edge curved portion 231 located closer to the tab 222 than the edge inclined portion 230. The edge curved portion 231 is formed continuously from the edge inclined portion 230 and is curved so as to be convex outward in a plan view. This allows the airflow flowing in from the tip 220p of the load beam 220 to flow along the curved shape of the edge curved portion 231. Therefore, even when the airflow flows in from the tip 220p of the load beam 220, the pressure that the edge portion 225 receives from the airflow can be reduced. As a result, the change in the flying attitude of the magnetic head can be reduced. In this case, the possibility of a decrease in the positioning accuracy of the magnetic head with respect to the magnetic disk 3 can be reduced.

[0277] According to this embodiment, the edge curved portion 231 includes the edge curved surface 234 that constitutes the second surface 221b and is formed in a curved shape. This allows the airflow that has flowed in from the tip 220p of the load beam 220 and reached the second surface 221b of the edge curved portion 231 to flow along the edge curved surface 234. This further reduces the pressure that the load beam 220 receives from the airflow flowing in from the tip. As a result, the change in the flying attitude of the magnetic head can be further reduced.

[0278] According to this embodiment, the surface roughness of the curved edge end surface 233 is greater than the surface roughness of the second surface 221b. This reduces the separation of the airflow downstream of the curved edge end surface 233. This reduces fluctuations in the pressure that the suspension 5 receives from the airflow. This stabilizes the flying posture of the magnetic head.

[0279] According to this embodiment, the surface roughness of the inclined edge end face 232 is greater than the surface roughness of the second surface 221b. This reduces the separation of the airflow downstream of the inclined edge end face 232. This reduces fluctuations in the pressure that the suspension 5 receives from the airflow. This stabilizes the flying posture of the magnetic head.

[0280] According to this embodiment, the blank plate body 261 of the load beam blank plate 260 includes a blank plate inclined end surface 263 and a blank plate curved end surface 264 located closer to the blank plate tab 262 than the blank plate inclined end surface 263. The blank plate inclined end surface 263 extends in a direction inclined with respect to the first direction D21 in plan view. The blank plate curved end surface 264 is formed continuously from the blank plate inclined end surface 263 and is curved so as to be convex outward in plan view. Thus, by bending the blank plate body 261 along the fold line 225L relative to the beam flat portion 224, a curved edge portion 231 can be formed that is located closer to the tab 222 than the inclined edge portion 230. The curved edge portion 231 is formed continuously from the inclined edge portion 230 and can be curved in plan view. Therefore, even if an airflow flows in from the tip 220p of the load beam 220, the pressure that the edge portion 225 receives from the airflow can be reduced.

[0281] The present disclosure is not limited to the above-described embodiments and modifications, and the components can be modified and embodied in practice without departing from the spirit of the present disclosure. Various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiments and modifications. Some components may be omitted from all the components shown in the embodiments and modifications.

Claims

1. A load beam comprising: a beam body extending in a first direction; and a tab extending in the first direction from the beam body to a tip of the load beam, wherein the tab includes a tab body, a thin portion adjacent to the tab body, and a tab edge portion adjacent to the thin portion and defining an end face of the tab, and the tab edge portion includes a thick portion that is thicker than the minimum thickness of the thin portion.

2. The load beam according to claim 1, wherein the maximum thickness of the thickened portion is thinner than the thickness of the tab body.

3. A load beam according to claim 1 or 2, wherein the thickened portion extends along the tab edge portion.

4. A load beam according to claim 1 or 2, wherein the tab end edge portions are located on both sides of the tab main body in a second direction perpendicular to the first direction in a plan view, the thin-walled portion is located between each of the tab end edge portions and the tab main body, and each of the tab end edge portions includes the thick-walled portion.

5. A load beam according to claim 1, wherein the tab includes a tab first surface and a tab second surface located opposite the tab first surface, the tab has a curved shape with the tab first surface facing inward when viewed in a cross section perpendicular to the first direction, and the thin-walled portion includes a concave surface recessed from the tab first surface.

6. The load beam according to claim 5, wherein the concave surface is formed in a curved shape when viewed in a cross section perpendicular to the first direction.

7. The load beam according to claim 1, wherein the tab includes a root region adjacent to the beam body and a body region located on the opposite side of the root region from the beam body, and the thickened portion is located in the body region.

8. The load beam according to claim 7, wherein the thickened portions are located in the root region and the body region.

9. The load beam according to claim 1, wherein the tab includes a root region adjacent to the beam body and a body region located on the opposite side of the root region from the beam body, and the thickened portion is located in the root region.

10. The load beam according to claim 1, wherein the tab includes a root region adjacent to the beam body, a tip region including the tip of the load beam, and a body region located between the root region and the tip region, and the thickened portion is located in the tip region.

11. The load beam of claim 10, wherein the thickened portions are located in the root region, the tip region, and the body region.

12. A load beam blank plate comprising: a flat blank plate body extending in a first direction; and a flat blank plate tab extending in the first direction from the blank plate body to a tip end of the load beam blank plate, the blank plate tab including a blank plate tab body, a thin portion adjacent to the blank plate tab body, and a tab end edge portion adjacent to the thin portion and defining an end face of the blank plate tab, the tab end edge portion including a thick portion that is thicker than the minimum thickness of the thin portion.

13. A load beam comprising: a beam flat portion; and a tab extending from the beam flat portion, wherein the tab has a tab first surface and a tab second surface located opposite the tab first surface, wherein the tab has a shape in which the tab first surface is curved inward in a cross section in a lateral direction perpendicular to the longitudinal direction of the load beam, and the thickness of the tab is thinner at the central portion in the lateral direction of the load beam than at both ends in the lateral direction.

14. The load beam according to claim 13, wherein the tab second surface has two outer curved surfaces and a central surface located between the two outer curved surfaces, and the central surface is formed discontinuously with the outer curved surfaces.

15. The load beam according to claim 14, wherein the central surface is a central flat surface formed flat.

16. The load beam according to claim 14, wherein the central surface is a central curved surface formed in a curved shape.

17. The load beam according to claim 16, wherein, in the cross section in the short direction, the outer curved surface and the central curved surface are each formed in an arc shape, and the radius of curvature of the central curved surface is larger than the radius of curvature of the outer curved surface.

18. The load beam according to claim 13, wherein the thickness of the tab at the central portion in the lateral direction is 30% to 85% of the thickness of the tab at the end portions in the lateral direction.

19. A method of manufacturing a load beam according to any one of claims 13 to 18, comprising the steps of: preparing a plate-like member; forming a thin-walled portion in the center of the portion of the plate-like member that corresponds to the tab; and, after the step of forming the thin-walled portion, bending the portion that corresponds to the tab so that the first surface of the tab faces inward.

20. A method for manufacturing a load beam according to claim 19, wherein the thinned portion is formed by etching.

21. A method for manufacturing a load beam according to any one of claims 13 to 18, comprising the steps of: preparing a plate-like member; bending a portion corresponding to the tab so that the first surface of the tab faces inward; and, after the step of bending the portion corresponding to the tab, thinning a region including the central portion of the second surface of the tab.

22. A method for manufacturing a load beam according to any one of claims 13 to 18, comprising the steps of: preparing a plate-like member; and bending a portion corresponding to the tab so that the tab first surface faces inward, and simultaneously thinning an area including the central portion of the tab second surface.

23. A load beam blank plate comprising: a flat blank plate main body; and a flat blank plate tab extending from the blank plate main body, wherein the blank plate tab has a tab first surface and a tab second surface located opposite the tab first surface, and the blank plate tab includes a thin portion located in the center in a short direction perpendicular to the longitudinal direction of the load beam blank plate, the thin portion being recessed from the tab second surface.

24. A load beam comprising: a tab located at the tip of the load beam and extending in a first direction; a beam flat portion extending in the first direction in a tapered manner toward the tab; and a pair of edge portions located on both sides of the beam flat portion in a second direction perpendicular to the first direction in a plan view, the pair of edge portions being bent relative to the beam flat portion, wherein the edge portions include an edge inclined portion extending in a direction inclined with respect to the first direction in a plan view, and an edge curved portion located closer to the tab than the edge inclined portion, the edge curved portion being formed continuously from the edge inclined portion and curved so as to be convex outward in a plan view.

25. A load beam according to claim 24, comprising: a first surface formed from the beam flat portion to the edge portion; and a second surface formed from the beam flat portion to the edge portion, the second surface being located opposite to the first surface, wherein the edge portion has a bent shape with the first surface facing inward, and the second surface at the edge curved portion is formed in a curved shape.

26. A load beam according to claim 24 or 25, wherein the edge curved portion is formed in an arc shape in plan view, and the radius of the edge curved portion in plan view is 0.8 mm or more and 1.8 mm or less.

27. A load beam according to claim 24 or 25, comprising: a first surface formed from the beam flat portion to the edge portion; and a second surface formed from the beam flat portion to the edge portion, the second surface being located opposite to the first surface, wherein the edge portion has a bent shape with the first surface facing inward, and the surface roughness of the end face of the edge curved portion is coarser than the surface roughness of the second surface.

28. The load beam according to claim 27, wherein the difference between the ten-point mean roughness of the end face of the edge curved portion and the ten-point mean roughness of the second surface is 0.100 μm or more and 0.350 μm or less.

29. The load beam according to claim 27, wherein the surface roughness of the end face of the edge inclination portion is greater than the surface roughness of the second surface.

30. A load beam blank plate comprising: a blank plate tab located at the tip of the load beam blank plate and extending in a first direction; and a blank plate main body extending in the first direction in a tapered manner toward the blank plate tab, wherein the blank plate main body includes a pair of blank plate inclined end faces extending in a direction inclined with respect to the first direction in a plan view; and a pair of blank plate curved end faces located closer to the blank plate tab than the blank plate inclined end faces, the pair of blank plate curved end faces being formed continuously from the corresponding blank plate inclined end faces and curved so as to be convex outward in a plan view.

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