Disk device

Abstract

To provide a disk device capable of suppressing a decrease in bonding force between a boss and an inner surface of a through hole.SOLUTION: A disk device according to an embodiment includes a first suspension and a second suspension. The first suspension has a first base plate attached to an arm. The second suspension has a second base plate attached to the arm. The arm, in which a through hole is provided, has a first surface and a second surface to which the through hole opens, and an inner surface that forms the through hole. The first base plate has a first boss that is stored in the through hole and is in contact with the inner surface. The second base plate has a second boss that is stored in the through hole and is in contact with the inner surface. At least a portion of the second boss is retained between the inner surface and the first boss.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a disk device. [Background technology]

[0002] A disk device such as a hard disk drive (HDD) includes, for example, a magnetic disk and a head stack assembly (HSA). The HSA includes a rotating carriage, a base plate attached to an arm of the carriage, a load beam extending from the base plate, a flexure attached to the load beam, and a magnetic head mounted on the flexure.

[0003] The base plate has a boss. The arm has a through hole into which the boss fits. The base plate is attached to the arm by joining the boss to the inner surface of the arm that forms the through hole. The carriage has a plurality of arms, and two base plates are attached to the arms other than the two ends of the plurality of arms. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 5,963,383 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, if the arm is thin, the through hole becomes short, which limits the length and arrangement of the two bosses that can be fitted into the through hole, which may result in insufficient force bonding at least one of the bosses to the inner surface of the through hole.

[0006] One example of a problem to be solved by the present invention is to provide a disk device capable of suppressing a decrease in the joining force between a boss and an inner surface of a through hole. [Means for solving the problem]

[0007] A disk device according to one embodiment includes a first magnetic head, a second magnetic head, a carriage, a first suspension, and a second suspension. The carriage has an arm and is configured to rotate. The first suspension has a first base plate attached to the arm and holds the first magnetic head. The second suspension has a second base plate attached to the arm and holds the second magnetic head. The arm has a first surface on which a through hole is provided and on which the through hole opens, a second surface located on the opposite side of the first surface and on which the through hole opens, and an inner surface forming the through hole. The first base plate has a third surface facing the first surface, and a first boss protruding from the third surface, housed in the through hole, and in contact with the inner surface. The second base plate has a fourth surface facing the second surface, and a second boss protruding from the fourth surface, housed in the through hole, and in contact with the inner surface. At least a portion of the second boss is retained between the inner surface and the first boss. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an exemplary exploded perspective view of a HDD according to the first embodiment. [Diagram 2] FIG. 2 is an exemplary cross-sectional view showing a portion of the HDD of the first embodiment. [Diagram 3] FIG. 3 is an exemplary plan view partially showing the HGA and the arm according to the first embodiment. [Figure 4] FIG. 4 is an exemplary cross-sectional view partially illustrating a plurality of HGAs and a plurality of arms according to the first embodiment. [Diagram 5]FIG. 5 is an exemplary cross-sectional view partially illustrating the arm and the base plate of the first embodiment. [Figure 6] FIG. 6 is an exemplary cross-sectional view partially illustrating an arm and a base plate according to the second embodiment. [Figure 7] FIG. 7 is an exemplary cross-sectional view partially illustrating an arm and a base plate according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) The first embodiment will be described below with reference to FIGS. 1 to 5. In this specification, components according to the embodiment and their descriptions may be described in a number of ways. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may be identified by names different from those in this specification. The components may also be described by expressions different from those in this specification.

[0010] In the following description, "inhibit" is defined as, for example, preventing the occurrence of an event, action, or influence, or reducing the magnitude of an event, action, or influence.

[0011] 1 is an exemplary exploded perspective view of a hard disk drive (HDD) 10 according to a first embodiment. The HDD 10 is an example of a disk device, and may also be called an electronic device, a storage device, an auxiliary storage device, or a magnetic disk device.

[0012] 1, the HDD 10 includes a housing 11, a plurality of magnetic disks 12, a spindle motor 13, a head stack assembly (HSA) 14, a voice coil motor (VCM) 15, a ramp load mechanism 16, and a printed circuit board (PCB) 17. The magnetic disks 12 may also be called disks or platters.

[0013] 1, for the sake of convenience, a Z axis and a Z direction are defined in this specification. The Z axis is provided along the thickness of the HDD 10. The Z direction is a direction along the Z axis, and includes a +Z direction indicated by the Z axis arrow and a -Z direction opposite to the Z axis arrow.

[0014] The housing 11 houses a plurality of magnetic disks 12, a spindle motor 13, an HSA 14, a VCM 15, and a ramp load mechanism 16. The housing 11 has a base 21, an inner cover 22, and an outer cover 23. However, the housing 11 is not limited to this example.

[0015] The base 21 is formed in a substantially rectangular box shape that is open in the +Z direction. The base 21 has a bottom wall 25 and side walls 26. The bottom wall 25 is formed in a substantially rectangular (quadrilateral) plate shape that extends substantially perpendicular to the Z direction. The bottom wall 25 has a bottom surface 25a that faces substantially in the +Z direction. The side walls 26 protrude from the edge of the bottom wall 25 in substantially the +Z direction and are formed in a substantially rectangular frame shape.

[0016] The inner cover 22 is attached to the end of the side wall 26 in the +Z direction by, for example, screws, and closes the base 21. The outer cover 23 covers the inner cover 22, and is attached to the end of the side wall 26 in the +Z direction by, for example, welding.

[0017] An air vent 27 is provided in the inner cover 22. Furthermore, an air vent 28 is provided in the outer cover 23. After components are attached inside the base 21 and the inner cover 22 and the outer cover 23 are attached to the base 21, air inside the housing 11 is evacuated through the air vents 27, 28. Furthermore, the inside of the housing 11 is filled with a gas other than air.

[0018] The gas filled inside the housing 11 is, for example, a low-density gas having a density lower than air, an inert gas having a low reactivity, etc. For example, helium is filled inside the housing 11. Note that the housing 11 may be filled with other fluids.

[0019] The vent hole 28 of the outer cover 23 is closed by a seal 29. The seal 29 air-tightly seals the vent hole 28 and restricts the fluid filled inside the housing 11 from leaking from the vent hole 28 to the outside of the housing 11.

[0020] The magnetic disks 12 are formed in a disk shape that spreads perpendicular to the Z direction. The magnetic disks 12 are arranged in the Z direction at intervals. Magnetic recording layers are provided on both sides of the magnetic disks 12.

[0021] The spindle motor 13 supports the multiple magnetic disks 12. The multiple magnetic disks 12 are held on a hub of the spindle motor 13 by, for example, a clamp spring. The spindle motor 13 rotates the multiple magnetic disks 12 as a unit.

[0022] The housing 11 further has a support shaft 31 spaced apart from the magnetic disk 12. The support shaft 31 protrudes, for example, from the bottom surface 25a of the bottom wall 25 in approximately the +Z direction. The HSA 14 is supported by the support shaft 31 so as to be rotatable.

[0023] The HSA 14 can rotate around a central axis Axh. The central axis Axh is an imaginary axis extending substantially in the Z direction. The central axis Axh is, for example, the center of rotation of the HSA 14 and is also the central axis of the support shaft 31.

[0024] The HSA 14 has a carriage 35, a plurality of head gimbal assemblies (HGA) 36, and a flexible printed circuit board (FPC) 37. The carriage 35 has an actuator block 41 and a plurality of arms 42.

[0025] The actuator block 41 and the arms 42 are integrally formed from, for example, an aluminum alloy. However, the materials of the actuator block 41 and the arms 42 are not limited to this example.

[0026] The actuator block 41 is attached to the support shaft 31 via a bearing so as to be rotatable about the central axis Axh, for example. This allows the carriage 35 to rotate about the central axis Axh of the support shaft 31.

[0027] Fig. 2 is an exemplary cross-sectional view showing a portion of the HDD 10 of the first embodiment. As shown in Fig. 2, the arms 42 protrude from the actuator block 41 in a direction substantially perpendicular to the central axis Axh. Note that the HSA 14 may be divided, and the arms 42 may protrude from each of the actuator blocks 41.

[0028] 3 is an exemplary plan view partially showing the HGA 36 and the arm 42 of the first embodiment. As shown in FIG. 3, for convenience, an X-axis and a Y-axis are further defined in this specification. The X-axis, the Y-axis, and the Z-axis are mutually orthogonal. The Y-axis is provided along the arm 42. Furthermore, an X-direction and a Y-direction are further defined in this specification. The X-direction is a direction along the X-axis, and includes a +X-direction indicated by an arrow of the X-axis, and a -X-direction that is the opposite direction of the arrow of the X-axis. The Y-direction is a direction along the Y-axis, and includes a +Y-direction indicated by an arrow of the Y-axis, and a -Y-direction that is the opposite direction of the arrow of the Y-axis.

[0029] The multiple arms 42 protrude in the +Y direction from the actuator block 41. Therefore, the Y direction is the longitudinal direction of the arms 42. The X direction is the lateral direction of the arms 42. The X and Y directions change as the carriage 35 rotates around the central axis Axh.

[0030] 2, the multiple arms 42 are disposed at intervals in the Z direction. Each of the arms 42 is formed in a plate shape that can enter the gap between adjacent magnetic disks 12. The multiple arms 42 extend approximately in parallel.

[0031] 4 is an exemplary cross-sectional view partially illustrating the multiple HGAs 36 and the multiple arms 42 of the first embodiment. As shown in FIG. 4, each of the multiple arms 42 has two seating surfaces 42a and 42b. The seating surface 42a is an example of a first surface. The seating surface 42b is an example of a second surface.

[0032] The seats 42a and 42b are provided at the end of the arm 42 in the +Y direction. The seat 42a is formed substantially flat and faces substantially in the +Z direction. The seat 42b is located on the opposite side to the seat 42a. The seat 42b is formed substantially flat and faces substantially in the -Z direction.

[0033] Each of the arms 42 is provided with a crimping hole 45. The crimping hole 45 is an example of a through hole. The crimping hole 45 is a circular hole that penetrates the arm 42 in approximately the Z direction so as to open to the seating surfaces 42a and 42b.

[0034] Each of the arms 42 further has an inner surface 45a that forms (defines, defines) the crimping hole 45. The inner surface 45a is a substantially cylindrical curved surface that extends substantially in the Z direction. In this embodiment, the diameter of the inner surface 45a is substantially constant.

[0035] Each of the multiple HGAs 36 is attached to the seat surface 42a or the seat surface 42b so as to protrude substantially in the +Y direction from the arm 42. As a result, the multiple HGAs 36 are arranged at intervals in the Z direction.

[0036] 2, the multiple HGAs 36 include two HGAs 36E, multiple HGAs 36U, and multiple HGAs 36D. The HGAs 36E, 36U, and 36D are formed substantially identically or substantially mirror-symmetrically to each other, except as specifically described below. In the following description, features common to the HGAs 36E, 36U, and 36D are described as features of the HGAs 36.

[0037] The two HGA 36E are attached to two arms 42 located at both ends of the multiple arms 42. One HGA 36E is attached to the seat 42b of the arm 42 located at the end in the +Z direction. The other HGA 36E is attached to the seat 42a of the arm 42 located at the end in the -Z direction.

[0038] The multiple HGAs 36U, 36D are positioned between the two HGAs 36E. The multiple HGAs 36U are attached to the seats 42a of the multiple arms 42 positioned between the two HGAs 36E. The multiple HGAs 36D are attached to the seats 42b of the multiple arms 42 positioned between the two HGAs 36E. That is, the two HGAs 36U, 36D are attached to the two seats 42a, 42b of the multiple arms 42 between the two HGAs 36E.

[0039] 3, each of the multiple HGAs 36 has a magnetic head 51 and a suspension 52. The magnetic head 51 may also be referred to as a slider. The magnetic head 51 and suspension 52 of the HGA36U are an example of a first magnetic head and a first suspension. The magnetic head 51 and suspension 52 of the HGA36D are an example of a second magnetic head and a second suspension.

[0040] The magnetic head 51 records and reproduces information on a corresponding one of the multiple magnetic disks 12. In other words, the magnetic head 51 reads and writes information from and to the magnetic disk 12.

[0041] The suspension 52 is attached to the arm 42 and holds the magnetic head 51. The suspension 52 has a base plate 55, a load beam 56, and a flexure 57.

[0042] The base plate 55 and the load beam 56 are made of, for example, stainless steel. However, the materials of the base plate 55 and the load beam 56 are not limited to this example. The base plate 55 and the load beam 56 may be made of different materials.

[0043] 4, the base plate 55 has a plate 61 and a boss 62. The plate 61 is formed in a generally rectangular plate shape that is generally perpendicular to the Z direction. The boss 62 protrudes from the plate 61. The boss 62 is formed in a generally cylindrical shape and is fitted into the crimping hole 45 of the arm 42.

[0044] The boss 62 is swaged to the arm 42, whereby the base plate 55 is attached to the arm 42 of the carriage 35. Note that the base plate 55 may be attached to the arm 42 by other methods.

[0045] The load beam 56 is formed in a plate shape that is thinner than the base plate 55. As shown in Fig. 3, the load beam 56 is attached to the plate 61 by, for example, spot welding. The load beam 56 may be attached to the plate 61 by other means.

[0046] The load beam 56 extends approximately in the +Y direction from the plate 61. For example, the load beam 56 extends obliquely from the plate 61 toward the corresponding magnetic disk 12.

[0047] The flexure 57 is a type of flexible printed wiring board formed in a long and narrow strip shape. The flexure 57 has, for example, a metallic backing layer, an insulating base layer, a conductive layer, and an insulating cover layer.

[0048] The flexure 57 extends along the arm 42, the load beam 56, and the plate 61. The flexure 57 is attached to the load beam 56 and the plate 61 by, for example, spot welding.

[0049] A gimbal portion 65 is provided at an end of the flexure 57 in the +Y direction. The magnetic head 51 is attached to the gimbal portion 65. The gimbal portion 65 holds the magnetic head 51 so that it can swing.

[0050] 1, an end of the flexure 57 in the -Y direction is connected to one end of the FPC 37 attached to the actuator block 41. Therefore, the flexure 57 electrically connects the magnetic head 51 and the FPC 37. The other end of the FPC 37 is connected to a connector provided on the bottom wall 25, for example.

[0051] The carriage 35, the magnetic head 51, and the suspension 52 are housed in the housing 11. The suspension 52 of the HGA 36D is closer to the bottom surface 25a than the suspension 52 of the HGA 36U. The arrangement of the HGAs 36U and 36D may be reversed.

[0052] The VCM 15 has a voice coil, a pair of yokes, and a magnet provided on the yokes. The voice coil is held by an actuator block 41. The VCM 15 moves the magnetic head 51 to a desired position by rotating the carriage 35 around a central axis Axh.

[0053] When the magnetic head 51 moves to the outer edge of the magnetic disk 12 due to the rotation of the HSA 14 by the VCM 15 , the ramp load mechanism 16 in FIG.

[0054] The PCB 17 is, for example, a rigid board such as a glass epoxy board, and is a multi-layer board or a build-up board, etc. The PCB 17 is disposed outside the housing 11 and attached to the bottom wall 25.

[0055] Various electronic components are mounted on the PCB 17, such as a relay connector electrically connected to the FPC 37, an interface (I / F) connector connected to a host computer, and a controller that controls the operation of the HDD 10. The relay connector is electrically connected to the FPC 37 via a connector provided on the bottom wall 25. The controller of the PCB 17 controls, for example, the spindle motor 13, the VCM 15, and the magnetic head 51.

[0056] 4, in the following description, the base plate 55 and the boss 62 of the HGA 36U are referred to as the base plate 55U and the boss 62U. The base plate 55U is an example of a first base plate. The boss 62U is an example of a first boss.

[0057] Furthermore, in the following description, the base plate 55 and the boss 62 of the HGA 36D are referred to as a base plate 55D and a boss 62D. The base plate 55D is an example of a second base plate. The boss 62D is an example of a second boss.

[0058] The plate 61 of the base plate 55U has a flat surface 71U. The flat surface 71U is an example of a third surface. The flat surface 71U is formed substantially flat and faces substantially in the -Z direction. The flat surface 71U faces the seating surface 42a and is in contact with the seating surface 42a.

[0059] The boss 62U protrudes from the plane 71U in the approximately -Z direction and is housed in the crimping hole 45. The boss 62U is crimped to an inner surface 45a of the crimping hole 45, whereby the base plate 55U is attached to the arm .

[0060] The plate 61 of the base plate 55D has a flat surface 71D. The flat surface 71D is an example of a fourth surface. The flat surface 71D is formed substantially flat and faces substantially in the +Z direction. The flat surface 71D faces the seating surface 42b and is in contact with the seating surface 42b.

[0061] The boss 62D protrudes from the flat surface 71D in approximately the +Z direction and is housed in the crimping hole 45. The boss 62D is crimped to an inner surface 45a of the crimping hole 45, whereby the base plate 55D is attached to the arm .

[0062] An insertion hole 75U is provided in the base plate 55U. The insertion hole 75U passes through the inside of the substantially cylindrical boss 62U and penetrates the base plate 55U in the substantially Z direction. Furthermore, an insertion hole 75D is provided in the base plate 55D. The insertion hole 75D passes through the inside of the substantially cylindrical boss 62D and penetrates the base plate 55D in the substantially Z direction.

[0063] The crimping hole 45 and the insertion holes 75U and 75D extend along a common central axis Axs. In other words, the crimping hole 45 and the insertion holes 75U and 75D are arranged coaxially. The crimping hole 45 and the insertion holes 75U and 75D may have different central axes.

[0064] The central axis Axs is an imaginary axis extending substantially in the Z direction. That is, the central axis Axh of rotation of the HSA 14 and the central axis Axs of the crimping hole 45 are disposed substantially parallel to each other. The crimping holes 45 of the multiple arms 42 are provided on the common central axis Axs.

[0065] For convenience, the axial direction, radial direction, and circumferential direction are defined below. The axial direction is the direction along the central axis Axs. The axial direction is equal to the Z direction. The radial direction is the direction perpendicular to the central axis Axs, and includes a plurality of directions perpendicular to the central axis Axs. The circumferential direction is the direction of rotation around the central axis Axs, and includes a clockwise rotation direction and a counterclockwise rotation direction around the central axis Axs.

[0066] Fig. 5 is an exemplary cross-sectional view partially illustrating the arm 42 and the base plates 55U, 55D of the first embodiment. As shown in Fig. 5, the boss 62U has an outer ring portion 81, an inner ring portion 82, and an intermediate portion 83. The outer ring portion 81 is an example of a first portion. The inner ring portion 82 is an example of a second portion.

[0067] The outer annular portion 81 is a generally cylindrical portion that protrudes from the plane 71U in the generally -Z direction. The outer annular portion 81 has an outer peripheral surface 81a and an inner peripheral surface 81b. The outer peripheral surface 81a is an example of a first outer surface. The inner peripheral surface 81b is an example of a first inner surface.

[0068] The outer peripheral surface 81a is a generally cylindrical curved surface facing radially outward. The outer peripheral surface 81a faces the inner surface 45a of the crimping hole 45. The outer peripheral surface 81a has a contact region 81c and a separation region 81d.

[0069] The contact area 81c is a substantially cylindrical curved surface that is spaced from the plane 71U in the substantially -Z direction and extends in the circumferential direction. The contact area 81c of the outer peripheral surface 81a of the outer ring portion 81 is in contact with the inner surface 45a. Substantially the entire area of ​​the contact area 81c in the circumferential direction is in contact with the inner surface 45a. In this embodiment, the boss 62U is crimped to the inner surface 45a, so that the contact area 81c bites into the inner surface 45a. As a result, the contact area 81c of the outer peripheral surface 81a is joined to the inner surface 45a.

[0070] The spaced region 81d is located between the plane 71U and the contact region 81c and is a generally cylindrical curved surface extending in the circumferential direction. The contact region 81c and the spaced region 81d form a continuous generally cylindrical curved surface. The spaced region 81d is spaced from the inner surface 45a.

[0071] The inner peripheral surface 81b is located on the opposite side to the outer peripheral surface 81a. The inner peripheral surface 81b is a substantially cylindrical curved surface facing inward in the radial direction. In other words, the inner peripheral surface 81b faces the inside of the crimping hole 45. The thickness T1 of the outer annular portion 81 is substantially constant. The thickness T1 is the distance between the outer peripheral surface 81a and the inner peripheral surface 81b.

[0072] In this embodiment, the outer peripheral surface 81a and the inner peripheral surface 81b of the outer annular portion 81 are formed in a generally conical shape tapered toward the +Z direction. Therefore, the distance between the spaced region 81d and the inner surface 45a is maximum at the end of the spaced region 81d in the +Z direction.

[0073] The inner annular portion 82 is a generally annular portion that is farther away from the plane 71U in the -Z direction than the outer annular portion 81. The inner annular portion 82 has an outer peripheral surface 82a and an inner peripheral surface 82b. The outer peripheral surface 82a is an example of a second outer surface. The inner peripheral surface 82b is an example of a second inner surface.

[0074] The outer peripheral surface 82a is a generally cylindrical curved surface facing radially outward. The outer peripheral surface 82a faces the inner surface 45a of the crimping hole 45. The diameter of the outer peripheral surface 82a of the inner ring portion 82 is smaller than the diameter of the outer peripheral surface 81a of the outer ring portion 81. The outer peripheral surface 82a is farther away from the inner surface 45a than the outer peripheral surface 81a is. The outer peripheral surface 82a and the inner surface 45a face each other with a gap therebetween.

[0075] The inner peripheral surface 82b is located on the opposite side to the outer peripheral surface 82a. The inner peripheral surface 82b is a substantially cylindrical curved surface facing inward in the radial direction. In other words, the inner peripheral surface 82b faces the inside of the crimping hole 45. The thickness T2 of the inner ring portion 82 is substantially constant. The thickness T2 is the distance between the outer peripheral surface 82a and the inner peripheral surface 82b.

[0076] The intermediate portion 83 is provided between the outer ring portion 81 and the inner ring portion 82. The inner ring portion 82 is connected to the outer ring portion 81 via the intermediate portion 83. The inner ring portion 82 may be directly connected to the outer ring portion 81. The intermediate portion 83 has an outer inclined surface 83a and an inner inclined surface 83b. The inner inclined surface 83b is an example of an inclined surface.

[0077] The outer inclined surface 83a extends obliquely with respect to the central axis Axs between an end of the outer peripheral surface 81a in the -Z direction and an end of the outer peripheral surface 82a in the +Z direction. The inner inclined surface 83b is located on the opposite side of the outer inclined surface 83a. The inner inclined surface 83b extends obliquely with respect to the central axis Axs between an end of the inner peripheral surface 81b in the -Z direction and an end of the inner peripheral surface 82b in the +Z direction.

[0078] The outer inclined surface 83a and the inner inclined surface 83b are formed in a generally conical shape tapering toward the -Z direction. In other words, the outer inclined surface 83a extends between the outer peripheral surface 81a and the outer peripheral surface 82a, and is formed in a generally conical shape tapering toward the outer peripheral surface 82a. The inner inclined surface 83b extends between the inner peripheral surface 81b and the inner peripheral surface 82b, and is formed in a generally conical shape tapering toward the inner peripheral surface 82b. The thickness T3 of the intermediate portion 83 is generally constant. The thickness T3 is the distance between the outer inclined surface 83a and the inner inclined surface 83b.

[0079] The thickness T1 of the outer annular portion 81 is smaller than the thickness T2 of the inner annular portion 82. The thickness T1 of the outer annular portion 81 and the thickness T3 of the middle portion 83 are approximately equal. That is, the inner annular portion 82 is thicker than the outer annular portion 81 and thicker than the middle portion 83.

[0080] The length Lu of the boss 62U protruding from the plane 71U is greater than half the distance Lh between the two seating surfaces 42a, 42b. The length Lu is the length of the boss 62U in the axial direction. The boss 62U has an outer peripheral surface 87 and an inner peripheral surface 88. The outer peripheral surface 87 is an example of an outer side surface. The inner peripheral surface 88 is an example of an inner side surface.

[0081] The outer circumferential surface 87 of the boss 62U has an outer circumferential surface 81a of the outer annular portion 81, an outer circumferential surface 82a of the inner annular portion 82, and an outer inclined surface 83a of the intermediate portion 83. The outer circumferential surface 87 and the inner surface 45a face each other.

[0082] An inner circumferential surface 88 of the boss 62U has an inner circumferential surface 81b of the outer annular portion 81, an inner circumferential surface 82b of the inner annular portion 82, and an inner inclined surface 83b of the intermediate portion 83. The inner circumferential surface 88 forms (defines, partitions) the insertion hole 75U. The inner circumferential surface 88 faces the inside of the crimp hole 45.

[0083] The inner circumferential surface 82b of the inner ring portion 82 is located at the innermost part of the inner circumferential surface 88 of the boss 62U, closest to the crimping hole 45. The inner circumferential surface 82b is located at least partially between the central plane Pm and the seating surface 42b. That is, the inner circumferential surface 82b is located between the two seating surfaces 42a, 42b. The central plane Pm is an imaginary plane that is the center between the two seating surfaces 42a, 42b. In this embodiment, the center of the inner circumferential surface 82b in the axial direction is located between the central plane Pm and the seating surface 42b.

[0084] At least a portion of the boss 62D is held between the inner surface 45a and the boss 62U. In other words, at least a portion of the boss 62D and a portion of the boss 62U overlap in the radial direction. In this embodiment, at least a portion of the boss 62D is held between the inner surface 45a and the outer circumferential surface 82a of the inner annular portion 82.

[0085] The boss 62D has an outer peripheral surface 91, an inner peripheral surface 92, and an end surface 93. The outer peripheral surface 91 is a generally cylindrical curved surface facing radially outward. The outer peripheral surface 91 and the inner surface 45a of the crimping hole 45 face each other. The outer peripheral surface 91 has a contact region 91a and a separation region 91b.

[0086] The contact area 91a is a generally cylindrical curved surface that is spaced from the plane 71D in the generally +Z direction and extends in the circumferential direction. The contact area 91a of the outer peripheral surface 91 is in contact with the inner surface 45a. In this embodiment, the boss 62D is crimped to the inner surface 45a, so that the contact area 91a bites into the inner surface 45a. As a result, the contact area 91a of the outer peripheral surface 91 is joined to the inner surface 45a.

[0087] The spaced region 91b is located between the flat surface 71D and the contact region 91a and is a generally cylindrical curved surface extending in the circumferential direction. The contact region 91a and the spaced region 91b form a continuous generally cylindrical curved surface. The spaced region 91b is spaced from the inner surface 45a.

[0088] The inner circumferential surface 92 is located on the opposite side to the outer circumferential surface 91. The inner circumferential surface 92 is a substantially cylindrical curved surface facing radially inward. In other words, the inner circumferential surface 92 faces the inside of the crimping hole 45. The inner circumferential surface 92 of the boss 62D is in contact with the outer circumferential surface 82a of the inner annular portion 82.

[0089] The thickness of the boss 62D is approximately constant. However, the boss 62D is compressed between the inner surface 45a of the crimping hole 45 and the inner annular portion 82 of the boss 62U. Therefore, the thickness T4 of the portion of the boss 62D that contacts the inner annular portion 82 and the thickness of the portion spaced apart from the boss 62U may be different from each other. The thickness T4 is the distance between the outer peripheral surface 91 and the inner peripheral surface 92.

[0090] A thickness T4 of the boss 62D is thinner than a thickness T1 of the outer annular portion 81. In other words, the outer annular portion 81 is thicker than the boss 62D. For example, the boss 62D becomes thinner than the outer annular portion 81 by being compressed between the inner surface 45a and the inner annular portion 82. It should be noted that the thickness T4 of the boss 62D is not limited to this example.

[0091] In this embodiment, the outer peripheral surface 91 and the inner peripheral surface 92 of the boss 62D are formed in a generally conical shape tapering in the -Z direction. Therefore, the distance between the spaced region 91b and the inner surface 45a is maximum at the end of the spaced region 91b in the -Z direction.

[0092] The end face 93 is located at an end of the boss 62D in the +Z direction. The +Z direction is an example of a direction in which the second boss protrudes from the fourth surface. The end face 93 faces the outer ring portion 81 and the intermediate portion 83 of the boss 62U. In this embodiment, the end face 93 faces the outer inclined surface 83a of the intermediate portion 83.

[0093] The end face 93 is spaced from the boss 62U. The distance between the end face 93 and the boss 62U is greater than the maximum distance between the spaced region 81d of the outer annular portion 81 and the inner surface 45a of the crimping hole 45. Furthermore, the distance between the end face 93 and the boss 62U is greater than the maximum distance between the spaced region 91b of the boss 62D and the inner surface 45a of the crimping hole 45.

[0094] 4, the shape of the boss 62 of the HGA 36E is different from the shapes of the bosses 62U and 62D. However, the shape of the boss 62 of the HGA 36E may be the same as the shape of the boss 62U, for example.

[0095] 3, a notch N is provided in plate 61 of base plate 55U. On the other hand, plate 61 of base plate 55D is provided with no notch N or with a notch of a different shape. By the notch N, it can be determined whether base plate 55 is base plate 55U or base plate 55D.

[0096] The following describes an example of a method for crimping the base plates 55U, 55D, which is part of a manufacturing method for the HDD 10. Note that the method for crimping the base plates 55U, 55D is not limited to the following method, and other methods may be used.

[0097] First, the bosses 62U, 62D are inserted into the crimping hole 45. Fig. 5 shows the bosses 62U, 62D before crimping by two-dot chain lines. The bosses 62U, 62D are inserted into the crimping hole 45 so that the inner annular portion 82 of the boss 62U and the boss 62D overlap in the radial direction.

[0098] Before crimping, the diameters of the outer peripheral surface 81a of the outer ring portion 81 and the outer peripheral surface 91 of the boss 62D are smaller than the diameter of the inner surface 45a of the crimping hole 45. Therefore, before crimping, at least a portion of the outer peripheral surface 81a of the outer ring portion 81 and the outer peripheral surface 91 of the boss 62D in the circumferential direction is separated from the inner surface 45a of the crimping hole 45.

[0099] Before crimping, the diameter of the outer circumferential surface 82a of the inner annular portion 82 is smaller than the diameter of the inner circumferential surface 92 of the boss 62D. Therefore, before crimping, at least a portion of the outer circumferential surface 82a of the inner annular portion 82 in the circumferential direction is separated from the inner circumferential surface 92 of the boss 62D.

[0100] Next, the ball B passes through the crimping hole 45 and the insertion holes 75U and 75D. The ball B is made of, for example, stainless steel. The rigidity of the ball B is higher than the rigidity of the boss 62U and higher than the rigidity of the boss 62D.

[0101] The ball B first enters the insertion hole 75U. That is, when the ball B passes through the insertion holes 75U and 75D and crimps the bosses 62U and 62D to the inner surface 45a, the boss 62U is located upstream and the boss 62D is located downstream. The diameter of the ball B is larger than the diameter of the inner peripheral surface 82b of the inner annular portion 82 before crimping. Therefore, the ball B comes into contact with, for example, the inner inclined surface 83b of the intermediate portion 83.

[0102] The ball B presses the inner inclined surface 83b in the -Z direction. The boss 62U is pulled in the -Z direction by the ball B and plastically deforms so as to expand. As a result, the outer peripheral surface 81a of the outer ring portion 81 comes into contact with the inner surface 45a of the crimping hole 45 and is joined to the inner surface 45a.

[0103] Furthermore, the outer peripheral surface 82a of the inner ring portion 82 comes into contact with the inner peripheral surface 92 of the boss 62D. The boss 62D is compressed by the inner ring portion 82 and plastically deformed so as to expand. As a result, the outer peripheral surface 91 of the boss 62D comes into contact with the inner surface 45a of the crimping hole 45 and is joined to the inner surface 45a.

[0104] The boss 62D is held between the inner surface 45a and the plastically deformed inner annular portion 82. In other words, the inner annular portion 82 presses the boss 62D against the inner surface 45a. Therefore, the boss 62D is firmly joined to the inner surface 45a.

[0105] Meanwhile, the outer peripheral surface 82a of the inner annular portion 82 contacts and is joined to the inner peripheral surface 92 of the boss 62D. Since the boss 62D is joined to the inner surface 45a, the outer peripheral surface 82a of the inner annular portion 82 is joined to the inner surface 45a via the boss 62D.

[0106] The boss 62D is joined to the inner surface 45a by plastic deformation, and is pressed against the inner surface 45a by the boss 62U. As a result, the boss 62D is firmly crimped to the inner surface 45a of the crimp hole 45.

[0107] The boss 62U is directly joined to the inner surface 45a by plastic deformation, and is also indirectly joined to the inner surface 45a via the boss 62D. As a result, the boss 62U is also firmly crimped to the inner surface 45a of the crimp hole 45.

[0108] As the inner ring portion 82 expands, the diameter of the inner circumferential surface 82b of the inner ring portion 82 becomes equal to or larger than the diameter of the ball B. Therefore, the ball B passes through the insertion holes 75U, 75D and enters the next insertion hole 75U. The ball B passes continuously through the insertion holes 75U, 75D of the multiple base plates 55U, 55D.

[0109] When the ball B presses the inner inclined surface 83b in the -Z direction, a curved surface 83c that is connected to the inner peripheral surface 82b is formed on the inner inclined surface 83b. In other words, the inner inclined surface 83b has the curved surface 83c. The curved surface 83c is a part of the inner inclined surface 83b. However, the curved surface 83c may be the entire inner inclined surface 83b.

[0110] The curved surface 83c is formed in a curved cone shape that bulges toward the central axis Axs. Therefore, the angle between the plane 71U and the curved surface 83c increases as it is farther from the plane 71U. The inner ring portion 82 and the intermediate portion 83 of the ball B are bent so that the curved surface 83c is formed. Note that the curved surface 83c does not have to be formed on the inner inclined surface 83b.

[0111] In this manner, the base plates 55U and 55D are attached to the arm 42 by crimping. The boss 62 of the HGA 36E is attached to the arm 42 by ordinary crimping. That is, the boss 62 of the HGA 36E is deformed so as to expand by the ball B, and is joined to the inner surface 45a of the arm 42.

[0112] In the HDD 10 according to the first embodiment described above, the arm 42 has a seat surface 42a, a seat surface 42b located on the opposite side of the seat surface 42a, and an inner surface 45a. The arm 42 is provided with a crimping hole 45 that opens to the seat surface 42a and the seat surface 42b. The inner surface 45a forms the crimping hole 45. The base plate 55U has a flat surface 71U facing the seat surface 42a and a boss 62U protruding from the flat surface 71U. The boss 62U is housed in the crimping hole 45 and contacts the inner surface 45a. The base plate 55D has a flat surface 71D facing the seat surface 42b and a boss 62D protruding from the flat surface 71D. The boss 62D is housed in the crimping hole 45 and contacts the inner surface 45a. At least a portion of the boss 62D is held between the inner surface 45a and the boss 62U.

[0113] When the arm 42 is thin between the seat surface 42a and the seat surface 42b, the direct contact area between each of the boss 62U and the boss 62D and the inner surface 45a may be small. On the other hand, the boss 62U of this embodiment is joined to the inner surface 45a by contacting the inner surface 45a, and holds the boss 62D between the inner surface 45a and the boss 62U. That is, the boss 62U overlaps at least a part of the boss 62D. The boss 62D is joined to the inner surface 45a by the boss 62D itself contacting the inner surface 45a, and is more firmly joined to the inner surface 45a by the boss 62U. Furthermore, the boss 62U is joined to the inner surface 45a by the boss 62U itself contacting the inner surface 45a, and is joined to the inner surface 45a via the boss 62D by contacting the boss 62D. As a result, even if the arm 42 is thin between the seating surface 42a and the seating surface 42b, the base plates 55U and 55D can prevent a decrease in the force joining the bosses 62U and 62D to the inner surface 45a. Therefore, in the HDD 10 of this embodiment, the arm 42 can be thinned between the seating surface 42a and the seating surface 42b, and the number of magnetic disks 12 can be increased.

[0114] Boss 62U has an outer circumferential surface 87 that faces the inner surface 45a. At least a portion of boss 62D is held between the inner surface 45a and the outer circumferential surface 87. This allows boss 62D to be joined to the inner surface 45a more firmly than if it were held between two surfaces that do not face each other.

[0115] The outer peripheral surface 87 has an outer peripheral surface 81a and an outer peripheral surface 82a. The outer peripheral surface 81a contacts the inner surface 45a. The outer peripheral surface 82a is farther away from the inner surface 45a than the outer peripheral surface 81a is. The outer peripheral surface 82a and the inner surface 45a face each other. At least a portion of the boss 62D is held between the inner surface 45a and the outer peripheral surface 82a. This allows the boss 62U to stably contact the inner surface 45a and stably hold the boss 62D between the inner surface 45a and the outer peripheral surface 82a, compared to a case in which the outer peripheral surface 87, which has a constant diameter, contacts the inner surface 45a and the boss 62D.

[0116] The boss 62U has inner peripheral surfaces 81b, 82b and an inner inclined surface 83b. The inner peripheral surface 81b is located on the opposite side of the outer peripheral surface 81a. The inner peripheral surface 82b is located on the opposite side of the outer peripheral surface 82a. The inner inclined surface 83b extends between the inner peripheral surface 81b and the inner peripheral surface 82b and tapers toward the inner peripheral surface 82b. The inner inclined surface 83b has a curved surface 83c connected to the inner peripheral surface 82b. The angle between the plane 71U and the curved surface 83c increases the farther it is from the plane 71U. In the crimping where the boss 62U is upstream and the boss 62D is downstream, the ball B presses the inner inclined surface 83b in the -Z direction to form the curved surface 83c on the inner inclined surface 83b. Because the ball B presses against the inner inclined surface 83b, the outer circumferential surface 82a comes into contact with the boss 62D more reliably, and the boss 62U can hold the boss 62D between the inner surface 45a and the outer circumferential surface 82a.

[0117] An end face 93 of the boss 62D in the +Z direction where the boss 62D protrudes from the plane 71D is spaced apart from the boss 62U. This prevents the end face 93 of the boss 62D from pushing the boss 62U out of the crimp hole 45 in the axial direction.

[0118] The outer peripheral surface 87 has a contact area 81c that contacts the inner surface 45a, and a separation area 81d that is located between the contact area 81c and the plane 71U and is separated from the inner surface 45a. The distance between the end surface 93 and the boss 62U is greater than the maximum distance between the separation area 81d and the inner surface 45a. This makes it possible for the boss 62D to prevent the end surface 93 from contacting the boss 62U due to, for example, dimensional variations.

[0119] The boss 62U has an outer ring portion 81 and an inner ring portion 82. The outer ring portion 81 protrudes from the plane 71U and contacts the inner surface 45a. The inner ring portion 82 is farther away from the plane 71U than the outer ring portion 81 and is thicker than the outer ring portion 81. At least a part of the boss 62D is held between the inner surface 45a and the inner ring portion 82. That is, the inner ring portion 82 that holds the boss 62D is thicker than the outer ring portion 81 that contacts the inner surface 45a. In crimping, the thick portion can be joined more firmly than the thin portion. Therefore, the boss 62U can be joined more firmly to the inner surface 45a via the boss 62D, and the boss 62D can be joined more firmly to the inner surface 45a by the boss 62U.

[0120] The outer annular portion 81 is thicker than the boss 62D. This allows the inner annular portion 82 of the boss 62U to be easily set thicker than when the boss 62D is thicker than the outer annular portion 81. Furthermore, the boss 62D becomes thinner by being compressed between the inner surface 45a and the inner annular portion 82, for example. That is, the inner annular portion 82 holds the boss 62D more firmly as the boss 62D becomes thinner between the inner surface 45a and the inner annular portion 82, so that the boss 62D can be prevented from coming off the crimping hole 45.

[0121] The boss 62U has an inner peripheral surface 88 facing the inside of the crimping hole 45. When the boss 62U is joined to the inner surface 45a by crimping, for example, the ball B presses the inner peripheral surface 82b of the inner peripheral surface 88 that is located on the inner side of the crimping hole 45. That is, the inner peripheral surface 82b of the boss 62U is pressed by the ball B, so that the boss 62D is held between the inner surface 45a and the boss 62U. The inner peripheral surface 82b is located between the seating surface 42a and the seating surface 42b. Therefore, the boss 62U pressed by the ball B can press the boss 62D against the inner surface 45a more directly. Therefore, the boss 62U can hold the boss 62D between the inner surface 45a and the boss 62U more reliably than when the inner peripheral surface 82b is located outside the crimping hole 45.

[0122] The inner peripheral surface 82b is at least partially located between the central plane Pm (the center between the seating surface 42a and the seating surface 42b) and the seating surface 42b. This allows the boss 62U to have a larger contact area with the inner surface 45a than when the inner peripheral surface 82b is located between the central plane Pm and the seating surface 42a. Therefore, the boss 62U can be more firmly joined to the inner surface 45a.

[0123] The length Lu of the boss 62U protruding from the plane 71U is greater than half the distance Lh between the seating surface 42a and the seating surface 42b. This allows the boss 62U to increase the contact area between the boss 62U and the inner surface 45a and to increase the contact area between the boss 62U and the boss 62D, compared to when the length Lu of the boss 62U is less than half the distance Lh between the seating surface 42a and the seating surface 42b. Therefore, even if the arm 42 is thin between the seating surface 42a and the seating surface 42b, the boss 62U can be more firmly joined to the inner surface 45a.

[0124] Second Embodiment The second embodiment will be described below with reference to Fig. 6. In the following description of the embodiments, components having the same functions as components already described are given the same reference numerals as the components already described, and further description may be omitted. Also, components given the same reference numerals do not necessarily have all the same functions and properties, and may have different functions and properties according to each embodiment.

[0125] Fig. 6 is an exemplary cross-sectional view partially illustrating the arm 42 and the base plates 55U and 55D according to the second embodiment. As shown in Fig. 6, the arm 42 of the second embodiment has an inner surface 200 instead of the inner surface 45a. The inner surface 200 is substantially equal to the inner surface 45a, except as described below.

[0126] The inner surface 200 has a first inner surface 201 and a second inner surface 202. The first inner surface 201 is closer to the seating surface 42a than the second inner surface 202. In this embodiment, the first inner surface 201 is connected to the seating surface 42a and is a substantially cylindrical curved surface extending from the seating surface 42a in the substantially -Z direction.

[0127] The boss 62U is crimped to the first inner surface 201. An outer peripheral surface 81a of the outer annular portion 81 is in contact with the first inner surface 201. The outer peripheral surface 81a bites into the first inner surface 201, whereby a contact region 81c of the outer peripheral surface 81a is joined to the first inner surface 201.

[0128] The second inner surface 202 is closer to the seating surface 42b than the first inner surface 201. In this embodiment, the second inner surface 202 is provided between the seating surface 42b and the first inner surface 201. The second inner surface 202 is recessed radially outward from the first inner surface 201. Therefore, the diameter of the second inner surface 202 is larger than the diameter of the first inner surface 201. The second inner surface 202 can be formed by, for example, etching.

[0129] The boss 62D of the second embodiment has a thin portion 211 and a thick portion 212. The thin portion 211 is a substantially cylindrical portion that protrudes from the plane 71D in the substantially +Z direction. The thick portion 212 is a substantially annular portion that is farther away from the plane 71D than the thin portion 211. In this embodiment, the thick portion 212 is connected to an end of the thin portion 211 in the +Z direction.

[0130] The thick portion 212 has an outer peripheral surface 212a and an inner peripheral surface 212b. The outer peripheral surface 212a is a generally cylindrical curved surface facing radially outward. The inner peripheral surface 212b is located on the opposite side of the outer peripheral surface 212a. The inner peripheral surface 212b is a generally cylindrical curved surface facing radially inward. In other words, the inner peripheral surface 212b faces the inside of the crimping hole 45.

[0131] The boss 62D is crimped to the second inner surface 202. The outer peripheral surface 212a is in contact with the second inner surface 202. The outer peripheral surface 212a is joined to the second inner surface 202 by being bitten into the second inner surface 202.

[0132] An inner peripheral surface 212b of the boss 62D contacts an outer peripheral surface 82a of the inner annular portion 82. The thick portion 212 of the boss 62D is held between the second inner surface 202 of the inner surface 200 and the outer peripheral surface 82a of the inner annular portion 82.

[0133] The thickness T5 of the thick portion 212 is thicker than the thickness T1 of the outer annular portion 81. In other words, the thick portion 212 of the boss 62D is thicker than the outer annular portion 81 of the boss 62U. The thick portion 212 is thicker than the thin portion 211.

[0134] For example, the diameter of an inner peripheral surface 212b of the thick portion 212 is approximately equal to the diameter of an inner peripheral surface 81b of the outer ring portion 81. However, the diameter of an outer peripheral surface 212a of the thick portion 212 is larger than the diameter of the outer peripheral surface 81a of the outer ring portion 81.

[0135] In the HDD 10 of the second embodiment described above, the boss 62U has an outer ring portion 81 that protrudes from the plane 71U and contacts the inner surface 200, and an inner ring portion 82 that is farther away from the plane 71U than the outer ring portion 82. The thick portion 212 of the boss 62D is held between the inner surface 200 and the inner ring portion 82, and is thicker than the outer ring portion 81. In crimping, the thick portion can be joined more firmly than the thin portion. Therefore, the boss 62D can be joined to the inner surface 200 more firmly.

[0136] The inner surface 200 has a first inner surface 201 that contacts the outer ring portion 81, and a second inner surface 202 that is recessed from the first inner surface 201 and contacts the boss 62D. This makes it possible to easily set the thick portion 212 of the boss 62D to be thick.

[0137] (Third embodiment) The third embodiment will be described below with reference to Fig. 7. Fig. 7 is an exemplary cross-sectional view partially illustrating the arm 42 and base plates 55U and 55D according to the third embodiment. As shown in Fig. 7, the boss 62U of the third embodiment has an inner ring portion 301 instead of the inner ring portion 82. The inner ring portion 301 is substantially equal to the inner ring portion 82, except as described below.

[0138] The thickness T2 of the inner ring portion 301 is equal to or less than the thickness T1 of the outer ring portion 81. Furthermore, the thickness T2 of the inner ring portion 301 is equal to or less than the thickness T4 of the boss 62D. Note that the thickness T2 of the inner ring portion 301 is not limited to this example.

[0139] Before crimping, the outer peripheral surface 82a of the inner ring portion 301 and the outer inclined surface 83a of the intermediate portion 83 are substantially continuous and formed into an integral conical shape tapering in the -Z direction. Furthermore, the inner peripheral surface 82b of the inner ring portion 301 and the inner inclined surface 83b of the intermediate portion 83 are substantially continuous and formed into an integral conical shape tapering in the -Z direction.

[0140] The ball B enters the insertion hole 75U and pushes the inner circumferential surface 82b, which tapers toward the -Z direction, in approximately the -Z direction. The boss 62U is pulled in the -Z direction by the ball B and plastically deforms so as to expand. As a result, the outer circumferential surface 81a of the outer ring portion 81 comes into contact with the inner surface 45a of the crimping hole 45 and is joined to the inner surface 45a.

[0141] Furthermore, because inner ring portion 301 is relatively thin, it bends relative to intermediate portion 83 when pressed by ball B. As a result, outer peripheral surface 82a of inner ring portion 301 comes into contact with inner peripheral surface 92 of boss 62D, and boss 62D is held between inner surface 45a and inner ring portion 301. A groove may be provided between inner ring portion 301 and intermediate portion 83 to make inner ring portion 301 easier to bend.

[0142] Because the inner peripheral surface 82b of the inner ring portion 301 before crimping tapers toward the -Z direction, the force with which the ball B presses the inner peripheral surface 82b includes a force (component) that presses the inner peripheral surface 82b radially outward. Therefore, bending of the inner ring portion 301 and joining of the outer peripheral surface 81a of the outer ring portion 81 to the inner surface 45a can be achieved at the same time.

[0143] In the HDD 10 of the third embodiment described above, the boss 62U is bent so as to hold the boss 62D between the inner surface 45a and the inner ring portion 301. This allows, for example, a large dimensional tolerance to be set for the fit between the inner ring portion 301 and the boss 62D.

[0144] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0145] 10...hard disk drive (HDD), 11...housing, 25a...bottom surface, 31...support shaft, 35...carriage, 42...arm, 42a, 42b...seat, 45...crimping hole, 45a, 200...inner surface, 51...magnetic head, 52...suspension, 55, 55U, 55D...base plate, 62, 62U, 62D...boss, 71U, 71D...flat surface, 81...outer ring portion, 81a...outer peripheral surface, 81c...contact area, 81d...separation area, 82, 301...inner ring portion, 82a...outer peripheral surface, 82b...inner peripheral surface, 87...outer peripheral surface, 88...inner peripheral surface, 93...end surface, 201...first inner surface, 202...second inner surface.

Claims

1. A first magnetic head; A second magnetic head; a carriage having an arm and configured to rotate; a first suspension having a first base plate attached to the arm and holding the first magnetic head; a second suspension having a second base plate attached to the arm and holding the second magnetic head; Equipped with the arm has a first surface in which a through hole is provided and in which the through hole opens, a second surface located opposite to the first surface and in which the through hole opens, and an inner surface that forms the through hole, the first base plate has a third surface facing the first surface, and a first boss protruding from the third surface, accommodated in the through hole, and in contact with the inner surface; the second base plate has a fourth surface facing the second surface, and a second boss protruding from the fourth surface, accommodated in the through hole, and in contact with the inner surface; At least a portion of the second boss is held between the inner surface and the first boss. Disk device.

2. The first boss has an outer surface facing the inner surface, At least a portion of the second boss is held between the inner surface and the outer surface.

2. The disk device according to claim 1.

3. The outer surface has a first outer surface in contact with the inner surface and a second outer surface facing the inner surface and spaced apart from the inner surface with respect to the first outer surface, At least a portion of the second boss is held between the inner surface and the second outer surface.

3. The disk device according to claim 2.

4. the first boss has a first inner side surface opposite the first outer side surface, a second inner side surface opposite the second outer side surface, and an inclined surface extending between the first inner side surface and the second inner side surface and tapering toward the second inner side surface; the inclined surface has a curved surface connected to the second inner surface, The angle between the third surface and the curved surface increases as the surface is farther from the third surface.

4. The disk device according to claim 3.

5. an end surface of the second boss in a direction in which the second boss protrudes from the fourth surface is spaced apart from the first boss; 3. The disk device according to claim 2.

6. the outer surface has a contact region in contact with the inner surface and a separation region located between the contact region and the third surface and spaced from the inner surface; a distance between the end surface and the first boss is greater than a maximum distance between the separation region and the inner surface; 6. The disk device according to claim 5.

7. the first boss has a first portion protruding from the third surface and contacting the inner surface, and a second portion that is farther away from the third surface than the first portion and is thicker than the first portion, At least a portion of the second boss is held between the inner surface and the second portion.

2. The disk device according to claim 1.

8. The first portion is thicker than the second boss.

8. The disk device according to claim 7.

9. the first boss has an inner surface facing the inside of the through hole, a portion of the inner surface located closest to the through hole is located between the first surface and the second surface; 2. The disk device according to claim 1.

10. A portion of the inner surface located closest to the through hole is at least partially located between the second surface and a center between the first surface and the second surface.

10. The disk device according to claim 9.

11. a length of the first boss protruding from the third surface is greater than half the distance between the first surface and the second surface; 2. The disk device according to claim 1.

12. the first boss has a first portion protruding from the third surface and contacting the inner surface, and a second portion spaced apart from the third surface more than the first portion, At least a portion of the second boss is retained between the inner surface and the second portion and is thicker than the first portion.

2. The disk device according to claim 1.

13. the inner surface includes a first inner surface in contact with the first portion, and a second inner surface recessed from the first inner surface and in contact with the second boss; The disk drive according to claim 12.

Images