disc device

Abstract

An embodiment of the present application provides a disc device capable of more firmly mounting two base plates to an arm. The disc device according to the embodiment has a first base plate, a second base plate, and a carriage. The carriage has an arm between the first base plate and the second base plate. The arm has an inner surface that defines a first through-hole. The first base plate has a plurality of first protrusions that contact the inner surface. The second base plate has a plurality of second protrusions that contact the inner surface. The plurality of first protrusions are arranged in a manner that the plurality of second protrusions are disposed between the plurality of first protrusions. The first base plate and the second base plate are mounted to each other by the plurality of first protrusions and the plurality of second protrusions contacting each other.

Description

[0001] This application claims priority to Japanese Patent Application No. 2025-024057 (filed on February 18, 2025). This application incorporates the entire contents of that basic application by reference. Technical Field

[0002] Embodiments of the present invention relate to a disk device. Background Technology

[0003] Disk devices such as hard disk drives (HDDs) have disks and head stack assemblies (HSAs). An HSA has a rotating carriage and a head gimbal assembly (HGA) mounted on the arm of the carriage.

[0004] An HGA, for example, has a base plate, a load beam extending from the base plate, a flexure mounted on the load beam, and a read / write head mounted on the flexure. A boss on the base plate is fitted into a through-hole in the arm. The base plate is mounted to the arm by contacting the inner surface of the arm with the defined through-hole through the boss. A carriage may have multiple arms, with two base plates mounted on each arm.

[0005] For example, when the arm is thin, the through hole becomes shorter, and the support area between each boss embedded in the through hole and the inner surface of the arm is limited. Due to this limitation, the bond between at least one boss and the inner surface of the arm may become weaker. Summary of the Invention

[0006] Embodiments of the present invention provide a disc device capable of more securely mounting two base plates to an arm.

[0007] The disk device of this embodiment includes a plurality of disks, a head gimbal assembly, a second base plate, and a carriage. The head gimbal assembly includes a read / write head configured to read / write information to one of the plurality of disks, and a first base plate. The carriage has an arm located between the first base plate and the second base plate, and is rotatable. The arm is provided with a first through-hole and has an inner surface defining the first through-hole. The first base plate has a first surface facing the arm and a plurality of first protrusions projecting from the first surface and mounted on the arm by contacting the inner surface. The second base plate has a second surface facing the arm and a plurality of second protrusions projecting from the second surface and mounted on the arm by contacting the inner surface. The plurality of first protrusions are arranged such that at least one of the plurality of second protrusions is positioned between adjacent pairs of first protrusions. The plurality of second protrusions are arranged such that at least one of the plurality of first protrusions is positioned between two adjacent second protrusions. The plurality of first protrusions and the plurality of second protrusions are in contact with each other, and the first base plate and the second base plate are mounted to each other. Attached Figure Description

[0008] Figure 1 This is an exemplary perspective view showing the HDD according to the first embodiment in an exploded view.

[0009] Figure 2 This is an exemplary cross-sectional view showing a portion of the HDD of the first embodiment.

[0010] Figure 3 This is a partial schematic plan view showing the HGA and arm of the first embodiment.

[0011] Figure 4 It is along Figure 3 The F4-F4 line partially shows an exemplary cross-sectional view of the two HGAs and arms of the first embodiment.

[0012] Figure 5 It is along Figure 4 The F5-F5 line partially shows an exemplary cross-sectional view of the arm and two base plates of the first embodiment.

[0013] Figure 6 This is a partial sectional view illustrating the arm and two base plates involved in the second embodiment.

[0014] Figure 7 This is a partial sectional view illustrating the arm and two base plates involved in the third embodiment.

[0015] Label Explanation

[0016] 10…Hard disk drive (HDD), 12…Disk, 35…Carriage, 36, 36U, 36D…Head gimbal assembly (HGA), 42…Arm, 45…Rivet hole, 45a…Inner surface, 51…Head, 55, 55U, 55D…Base plate, 81U, 81D…Flat surface, 82U, 82D…Through hole, 83U, 83D, 200U, 200D, 301U, 301D, 302U, 302D…Protrusion, 92U, 92D, 93U, 93D, 203U, 203D…Side surface, 201U, 201D…End face, 205U, 205D…Outer surface, 311U, 311D…Bevel, Axs…Central axis. Detailed Implementation

[0017] (First Embodiment)

[0018] The following is for reference Figures 1 to 5 The first embodiment will be described. Furthermore, in this specification, sometimes multiple descriptions are used to describe the constituent elements involved in the embodiment and their descriptions. The constituent elements and their descriptions are merely examples and are not limited to the descriptions in this specification. Constituent elements may also be identified by names different from those used in this specification. Additionally, constituent elements may also be described using descriptions different from those used in this specification.

[0019] In the following description, "to suppress" is defined, for example, to prevent the occurrence of an event, effect, or influence, or to reduce the degree of an event, effect, or influence.

[0020] Figure 1 This is an exemplary perspective view showing the hard disk drive (HDD) 10 according to the first embodiment in an exploded view. The HDD 10 is an example of a disk device, and may also be referred to as an electronic device, a storage device, an auxiliary storage device, or a disk device.

[0021] like Figure 1 As shown, HDD10 has a housing 11, multiple 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 disks 12 can also be referred to as platters or disks.

[0022] like Figure 1 As shown, for convenience, the Z-axis and Z-direction are defined in this specification. The Z-axis is set along the thickness of the HDD10. The Z-direction is along the Z-axis and includes the +Z direction indicated by the arrow of the Z-axis and the -Z direction, which is the opposite direction of the arrow of the Z-axis.

[0023] The housing 11 houses multiple disks 12, a spindle motor 13, an HSA 14, a VCM 15, and a ramp loading mechanism 16. The housing 11 has a base 21, an inner cover 22, and an outer cover 23. Furthermore, the housing 11 is not limited to this example.

[0024] The substrate 21 is formed as a generally cuboid box shape open in the +Z direction. The substrate 21 has a bottom wall 25 and side walls 26. The bottom wall 25 is formed as a generally rectangular (quadrilateral) plate extending in a manner generally orthogonal to the Z direction. The bottom wall 25 has a bottom surface 25a generally facing the +Z direction. The side walls 26 protrude from the edge of the bottom wall 25 in the generally +Z direction, forming a generally rectangular frame shape.

[0025] The inner cover 22 is installed, for example, by a threaded connection to the end of the side wall 26 in the +Z direction, to close the base 21. The outer cover 23 covers the inner cover 22, for example, by welding to the end of the side wall 26 in the +Z direction.

[0026] A vent 27 is provided in the inner cover 22. Furthermore, a vent 28 is provided in the outer cover 23. After the component is installed inside the base 21 and the inner cover 22 and outer cover 23 are installed in the base 21, air inside the housing 11 is extracted through the vents 27 and 28. Then, a gas different from air is filled into the housing 11.

[0027] The gas filling the interior of the casing 11 may be a low-density gas with a density lower than air, or an inert gas with low reactivity. For example, helium is filled inside the casing 11. In addition, other fluids may also be filled inside the casing 11.

[0028] The vent 28 of the outer cover 23 is sealed by a seal 29. The seal 29 seals the vent 28 in an airtight manner, limiting the leakage of fluid inside the housing 11 from the vent 28 to the outside of the housing 11.

[0029] The HDD 10 of this embodiment has, for example, twelve or more disks 12. Alternatively, the HDD 10 may have fewer than twelve disks 12. Each of the disks 12 is formed in a disk shape and arranged orthogonally to the Z-direction. The disks 12 are arranged at intervals in the Z-direction. Magnetic recording layers are provided on both sides of the disks 12.

[0030] The spindle motor 13 supports a plurality of disks 12. The plurality of disks 12 are held in the hub of the spindle motor 13, for example by clamping springs. The spindle motor 13 causes the plurality of disks 12 to rotate as a whole.

[0031] The housing 11 also has a support shaft 31 separate from the disk 12. The support shaft 31 protrudes, for example, from the bottom surface 25a of the bottom wall 25 in a generally +Z direction. The HSA 14 is rotatably supported on the support shaft 31.

[0032] HSA14 is capable of rotating about its central axis Axh. The central axis Axh is an imaginary axis extending approximately in the Z direction. The central axis Axh is, for example, the center of rotation of HSA14 and also the central axis of the support shaft 31.

[0033] Figure 2 This is an illustrative cross-sectional view showing a portion of the HDD10 according to the first embodiment. (See attached image.) Figure 2 As shown, the HSA14 has a carriage 35, multiple head universal joint assemblies (HGA) 36, and two dummy masses 37. Additionally, as... Figure 1 As shown, HSA14 has a flexible printed circuit board (FPC) 38. The carriage 35 has an actuator block 41 and multiple arms 42.

[0034] The actuator block 41 and the plurality of arms 42 are integrally formed, for example, by aluminum alloy. Furthermore, the materials of the actuator block 41 and the arms 42 are not limited to this example.

[0035] The actuator block 41 is mounted on the support shaft 31 via a bearing, for example, in a manner that allows it to rotate about the central axis Axh. Thus, the carriage 35 can rotate relative to the housing 11 about the central axis Axh of the support shaft 31.

[0036] like Figure 2 As shown, multiple arms 42 protrude from actuator block 41 in a direction substantially orthogonal to the central axis Axh. Alternatively, HSA14 can be segmented, with arms 42 protruding from each of the multiple actuator blocks 41.

[0037] Figure 3 This is a partial schematic plan view showing the HGA36 and arm 42 of the first embodiment. (See attached diagram.) Figure 3 As shown, for convenience, the X-axis and Y-axis are further defined in this specification. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The Y-axis is set along arm 42. Furthermore, the X-direction and Y-direction are further defined in this specification. The X-direction is the direction along the X-axis, including the +X direction indicated by the arrow of the X-axis and the -X direction, which is the opposite direction of the arrow of the X-axis. The Y-direction is the direction along the Y-axis, including the +Y direction indicated by the arrow of the Y-axis and the -Y direction, which is the opposite direction of the arrow of the Y-axis.

[0038] Multiple arms 42 protrude from the actuator block 41 in the +Y direction. Therefore, the Y direction is the direction of the long dimension of the arms 42. The X direction is the direction of the short dimension of the arms 42. The X and Y directions change due to the rotation of the carriage 35 relative to the housing 11 about the central axis Axh.

[0039] like Figure 2 As shown, multiple arms 42 are arranged at intervals in the Z direction. Each arm 42 is formed as a plate that can enter the gap between adjacent disks 12. The multiple arms 42 extend generally parallel to each other.

[0040] Figure 4 It is along Figure 3 The F4-F4 line partially shows an exemplary cross-sectional view of the two HGA36 and arm 42 of the first embodiment. (See figure) Figure 4 As shown, each of the multiple arms 42 has two support surfaces 42a and 42b.

[0041] Support surfaces 42a and 42b are provided at the end of arm 42 in the +Y direction. Support surface 42a is formed to be generally flat and faces approximately in the +Z direction. Support surface 42b is located on the opposite side of support surface 42a. Support surface 42b is formed to be generally flat and faces approximately in the -Z direction.

[0042] Each of the multiple arms 42 is provided with a riveting hole 45. The riveting hole 45 is an example of a first through hole. The riveting hole 45 is a circular hole that passes through the arm 42 in the generally Z direction, with openings on the support surfaces 42a and 42b.

[0043] Each of the plurality of arms 42 also has an inner surface 45a that defines the riveting hole 45. The inner surface 45a is a generally cylindrical curved surface extending along the central axis Axs of the riveting hole 45. In this embodiment, the diameter of the inner surface 45a is approximately constant.

[0044] The central axis Axs is an imaginary axis extending approximately in the Z direction. That is, the central axis Axh of rotation of HSA14 is configured approximately parallel to the central axis Axs of the riveting hole 45. In addition, the riveting holes 45 of the multiple arms 42 are provided on a common central axis Axs.

[0045] In this specification, for convenience, axial, radial, and circumferential directions are further defined. The axial direction is along the central axis Axs. In this embodiment, the axial direction is approximately equivalent to the Z direction. The radial direction is orthogonal to the central axis Axs. The circumferential direction is the direction about the central axis Axs. The circumferential direction includes... Figure 3 The diagram shows the first circumferential direction Dc1 and the second circumferential direction Dc2. The first circumferential direction Dc1 is a direction about the central axis Axs. The second circumferential direction Dc2 is the opposite direction of the first circumferential direction Dc1.

[0046] Each of the plurality of HGA36s is mounted on the support surface 42a or support surface 42b in a manner that protrudes from the arm 42 in a generally +Y direction. Thus, the plurality of HGA36s are arranged at intervals in the Z direction.

[0047] like Figure 2 As shown, the multiple HGA36s include multiple HGA36Us and multiple HGA36Ds. Except for the points specifically noted below, the HGA36Us and HGA36Ds are formed to be approximately mirror-symmetrical to each other. In the following description, features common to the HGA36Us and HGA36Ds will be described as features of the HGA36s.

[0048] In addition, the two dummy blocks 37 include dummy block 37U and dummy block 37D. Except for the points specifically noted below, dummy blocks 37U and dummy blocks 37D are formed to be approximately mirror-symmetrical to each other.

[0049] HGA36D and dummy block 37U are installed on one arm 42 located at the +Z direction edge of the multiple arms 42 arranged along the Z direction. HGA36U and dummy block 37D are installed on one arm 42 located at the -Z direction edge of the multiple arms 42 arranged along the Z direction. HGA36U and 36D are installed on the remaining arms 42 of the multiple arms 42. That is, multiple HGA36U and 36D are located between two dummy blocks 37U and 37D.

[0050] like Figure 4 As shown, multiple HGA36Us are respectively mounted on the support surface 42a of one of the multiple arms 42. Multiple HGA36Ds are respectively mounted on the support surface 42b of one of the multiple arms 42.

[0051] like Figure 3 As shown, each of the multiple HGA36 disks has a read / write head 51 and a suspension 52. The read / write head 51 can also be referred to as a slider. The read / write head 51 records and reproduces information on one of the multiple disks 12. In other words, the read / write head 51 reads and writes information on the disk 12.

[0052] The suspension 52 is mounted on the arm 42 to hold the magnetic head 51. The suspension 52 has a base plate 55, a load-bearing beam 56, and a flexible element 57.

[0053] The base plate 55 and the load-bearing beam 56 are made of, for example, stainless steel. However, the materials of the base plate 55 and the load-bearing beam 56 are not limited to this example; they could also be other metals. The base plate 55 and the load-bearing beam 56 can also be made of different materials.

[0054] like Figure 4As shown, the base plate 55 has a plate 61 and a boss 62. The plate 61 is formed into a generally quadrilateral plate shape and is configured to be generally orthogonal to the Z direction. The boss 62 protrudes from the plate 61. The boss 62 is formed into a generally cylindrical shape extending along the central axis Axs and is embedded in the rivet hole 45 of the arm 42.

[0055] The base plate 55 is riveted to the arm 42 of the carriage 35 via the boss 62. Alternatively, the base plate 55 can also be mounted to the arm 42 by other methods.

[0056] The load-bearing beam 56 is formed as a plate thinner than the base plate 55. For example... Figure 3 As shown, the load-bearing beam 56 is mounted to the plate 61, for example, by spot welding. Alternatively, the load-bearing beam 56 can also be mounted to the plate 61 by other means.

[0057] The load-bearing beam 56 extends from the plate 61 in a generally +Y direction. For example, the load-bearing beam 56 extends obliquely from the plate 61 toward the corresponding disk 12.

[0058] The flexible element 57 is an FPC formed in the shape of an elongated strip. The flexible element 57 may have, for example, a metal liner layer, an insulating substrate layer, a conductive layer, and an insulating capping layer.

[0059] Flexible member 57 extends along arm 42, load-bearing beam 56, and plate 61. Flexible member 57 is mounted to load-bearing beam 56 and plate 61, for example, by spot welding.

[0060] A gimbal 65 is provided at the end of the flexible member 57 in the +Y direction. A magnetic head 51 is mounted on the gimbal 65. The gimbal 65 holds the magnetic head 51 in a swingable position.

[0061] like Figure 1 As shown, one end of the FPC38 is mounted to the actuator block 41. The end of the flexible member 57 in the -Y direction is connected to this end of the FPC38. Therefore, the flexible member 57 electrically connects the magnetic head 51 to the FPC38. The other end of the FPC38 is connected, for example, to a connector provided on the bottom wall 25.

[0062] The carriage 35, the magnetic head 51, and the suspension 52 are housed in the housing 11. Figure 2 As shown, each of the multiple HGA36Ds is closer to the bottom surface 25a than the HGA36U mounted on the common arm 42. Furthermore, the configuration of the HGA36U and 36Ds can also be reversed.

[0063] like Figure 1 As shown, VCM15 has a voice coil, a pair of yokes, and a magnet disposed on the yokes. The voice coil is held in actuator block 41. VCM15 moves the magnetic head 51 to the desired position by rotating carriage 35 about central axis Axh.

[0064] When the read / write head 51 moves to the outer edge of the disk 12 due to the rotation of the HSA14 based on the VCM15, the ramp loading mechanism 16 holds the read / write head 51 in a position away from the disk 12.

[0065] PCB17 is, for example, a rigid substrate such as a glass epoxy board, or a multilayer substrate or a laminated substrate. PCB17 is disposed outside the housing 11 and mounted on the bottom wall 25.

[0066] The PCB17 is equipped with various electronic components, such as a relay connector 71 electrically connected to the FPC38, an interface (I / F) connector 72 connected to the host computer, and a controller 73 that controls the operation of the HDD10.

[0067] The relay connector 71 is electrically connected to the FPC 38 via a connector located on the bottom wall 25. The controller 73 controls, for example, the spindle motor 13, the VCM 15, and the magnetic head 51.

[0068] like Figure 4 As shown, in the following description, the base plate 55 and boss 62 of HGA36U are referred to as base plate 55U and boss 62U. Base plate 55U is an example of a first base plate. Furthermore, in the following description, the base plate 55 and boss 62 of HGA36D are referred to as base plate 55D and boss 62D. Base plate 55D is an example of a second base plate. Arm 42 is located between plate 61 of base plate 55U and plate 61 of base plate 55D.

[0069] The plate 61 of the base plate 55U has a plane 81U. Plane 81U is an example of the first surface. Plane 81U is formed to be generally flat and faces approximately in the -Z direction. Plane 81U faces and contacts the support surface 42a of the arm 42. Alternatively, plane 81U can be separated from the support surface 42a.

[0070] A through hole 82U is provided on plate 61 of base plate 55U. The through hole 82U is an example of the second through hole. The through hole 82U is a circular hole that penetrates plate 61 in the approximately Z direction along the central axis Axs. The through hole 82U communicates with the riveting hole 45 of arm 42.

[0071] Figure 5 It is along Figure 4 The F5-F5 line partially shows an exemplary cross-sectional view of the arm 42 and the base plates 55U and 55D of the first embodiment. (See also...) Figure 5As shown, the boss 62U is provided with two or more slots S1, which divide it into two or more protrusions 83U. In other words, the boss 62U has two or more protrusions 83U. In this embodiment, the boss 62U is provided with four slots S1 and has four protrusions 83U. Furthermore, the number of slots S1 and protrusions 83U is not limited to this example. Multiple protrusions 83U are an example of multiple first protrusions.

[0072] like Figure 4 As shown, multiple protrusions 83U protrude from the plane 81U in a generally -Z direction. In this embodiment, the multiple protrusions 83U protrude from the edge of the through hole 82U in the plane 81U and are arranged around the through hole 82U with gaps (grooves S1) spaced apart. That is, as Figure 5 As shown, multiple protrusions 83U are arranged in a ring shape (without joints) around the central axis Axs, separated by gaps (grooves S1).

[0073] The through hole 82U, the multiple slots S1, and the multiple protrusions 83U are arranged concentrically (coaxially) with the riveting hole 45. Furthermore, the central axes of the riveting hole 45, the through hole 82U, the multiple slots S1, and the multiple protrusions 83U may be different from each other.

[0074] In this embodiment, the groove S1 is provided, for example, between the edge of the boss 62U in the -Z direction and the plane 81U. That is, in the axial direction, the length (depth) of the groove S1 is approximately equal to the length of the boss 62U. Furthermore, the depth of the groove S1 is not limited to this example. For example, the boss 62U may also have a portion that connects two adjacent protrusions 83U among a plurality of protrusions 83U. In this case, the groove S1 is provided between the edge of the boss 62U in the -Z direction and this portion.

[0075] Multiple protrusions 83U are received in rivet holes 45 and riveted to the inner surface 45a. That is, the multiple protrusions 83U are mounted to the arm 42 by contacting the inner surface 45a. Alternatively, the protrusions 83U can also be mounted to the arm 42 by other methods.

[0076] The multiple protrusions 83U each have an outer peripheral surface 91U and two side surfaces 92U and 93U. The side surfaces 92U and 93U are examples of the first side surface. The outer peripheral surface 91U is a generally arc-shaped curved surface extending in the circumferential direction. The outer peripheral surface 91U faces radially outward and contacts the inner surface 45a of the arm 42.

[0077] Side surface 92U is the end face of the protrusion 83U on the first circumferential direction Dc1. Side surface 92U is formed to be generally flat and faces the first circumferential direction Dc1. Furthermore, side surface 92U may not be planar if it faces the first circumferential direction Dc1 as a whole.

[0078] Side surface 93U is the end face of protrusion 83U on the second circumferential direction Dc2. That is, side surface 93U is located on the opposite side surface 92U. Side surface 93U is formed to be generally flat, facing the second circumferential direction Dc2. Furthermore, side surface 93U may not be planar if it faces the second circumferential direction Dc2 as a whole.

[0079] like Figure 4 As shown, the plate 61 of the substrate plate 55D has a plane 81D. Plane 81D is an example of a second surface. Plane 81D is formed to be generally flat and faces approximately in the +Z direction. Plane 81D faces and contacts the support surface 42b of the arm 42. Furthermore, plane 81D can also be separated from the support surface 42b.

[0080] A through hole 82D is provided on plate 61 of base plate 55D. The through hole 82D is an example of the third through hole. The through hole 82D is a circular hole that passes through plate 61 in the approximately Z direction along the central axis Axs. The through hole 82D communicates with the riveting hole 45 of arm 42.

[0081] The boss 62D is provided with two or more slots S2 and is divided into two or more protrusions 83D by these slots S2. In other words, the boss 62D has two or more protrusions 83D. In this embodiment, the boss 62D is provided with four slots S2 and has four protrusions 83D. Furthermore, the number of slots S2 and protrusions 83D is not limited to this example. Multiple protrusions 83D are an example of multiple second protrusions.

[0082] Multiple protrusions 83D protrude from the plane 81D in a generally +Z direction. In this embodiment, the multiple protrusions 83D protrude from the edge of the through hole 82D in the plane 81D and are arranged around the through hole 82D with gaps (grooves S2) spaced apart. That is, as Figure 5 As shown, multiple protrusions 83D are arranged in a ring shape with gaps (grooves S2) around the central axis Axs.

[0083] The through hole 82D, multiple slots S2, and multiple protrusions 83D are concentrically arranged with the riveting hole 45. In addition, the central axes of the riveting hole 45, the through hole 82D, the multiple slots S2, and the multiple protrusions 83D may be different from each other.

[0084] In this embodiment, the groove S2 is provided, for example, between the edge of the boss 62D in the +Z direction and the plane 81D. That is, in the axial direction, the length (depth) of the groove S2 is approximately equal to the length of the boss 62D. Furthermore, the depth of the groove S2 is not limited to this example. For example, the boss 62D may also have a portion that connects two adjacent protrusions 83D among a plurality of protrusions 83D. In this case, the groove S2 is provided between the edge of the boss 62D in the +Z direction and this portion.

[0085] Multiple protrusions 83D are received in rivet holes 45 and riveted to the inner surface 45a. That is, the multiple protrusions 83D are mounted to the arm 42 by contacting the inner surface 45a. Alternatively, the protrusions 83D can also be mounted to the arm 42 by other methods.

[0086] Each of the protrusions 83D has an outer peripheral surface 91D and two side surfaces 92D and 93D. Side surfaces 92D and 93D are examples of a second side surface. The outer peripheral surface 91D is a generally arc-shaped curved surface extending circumferentially. The outer peripheral surface 91D faces radially outward and contacts the inner surface 45a of the arm 42.

[0087] Side surface 92D is the end face of protrusion 83D on the first circumferential direction Dc1. Side surface 92D is formed to be generally flat, facing the first circumferential direction Dc1. Furthermore, side surface 92D may not be planar if it faces the first circumferential direction Dc1 as a whole.

[0088] Side face 93D is the end face of the protrusion 83D on the second circumferential direction Dc2. That is, side face 93D is located on the opposite side face 92D. Side face 93D is formed to be generally flat, facing the second circumferential direction Dc2. Furthermore, side face 93D may not be planar if it faces the second circumferential direction Dc2 as a whole.

[0089] In the circumferential direction, the positions of the multiple protrusions 83U and the multiple protrusions 83D are different from each other. Similarly, in the circumferential direction, the positions of the multiple slots S1 and the multiple slots S2 are different from each other. For example, the positions of the multiple protrusions 83U and the multiple slots S1, and the positions of the multiple protrusions 83D and the multiple slots S2, are configured to be mirror-symmetrical to each other. In this case, the base plates 55U and 55D can be common. Furthermore, the positions of the protrusions 83U and 83D, and the slots S1 and S2 are not limited to this example.

[0090] Multiple protrusions 83U are embedded in multiple slots S2. Additionally, multiple protrusions 83D are embedded in multiple slots S1. That is, the multiple protrusions 83U are arranged such that at least one of the multiple protrusions 83D is positioned between two adjacent protrusions 83U. Furthermore, the multiple protrusions 83D are arranged such that at least one of the multiple protrusions 83U is positioned between two adjacent protrusions 83D.

[0091] In this embodiment, multiple protrusions 83U and multiple protrusions 83D are arranged alternately around the central axis Axs. Furthermore, either two or more protrusions 83U can be embedded in a slot S2, or two or more protrusions 83D can be embedded in a slot S1.

[0092] like Figure 4As shown, in the axial direction, the length of the protrusion 83U is more than half the length of the riveting hole 45 and less than the length of the riveting hole 45. Furthermore, the length of the protrusion 83U is not limited to this example; it can be either shorter than half the length of the riveting hole 45 or longer than the length of the riveting hole 45.

[0093] In the axial direction, the length of the protrusion 83D is more than half the length of the riveting hole 45 and less than the length of the riveting hole 45. Furthermore, the length of the protrusion 83D is not limited to this example; it can be either shorter than half the length of the riveting hole 45 or longer than the length of the riveting hole 45.

[0094] Since the lengths of the protrusions 83U and 83D are more than half the length of the riveting hole 45, multiple protrusions 83U and multiple protrusions 83D overlap circumferentially at the center C in the axial direction of the riveting hole 45. Figure 4 The center C is imaginary, indicated by a single-dotted line. Furthermore, the center C is also the axial center of the inner surface 45a.

[0095] Multiple protrusions 83U are located at or closer to the plane 81D than at the center C, and contact the inner surface 45a of the arm 42. Additionally, multiple protrusions 83D are located at or closer to the plane 81U than at the center C, and contact the inner surface 45a.

[0096] like Figure 5 As shown, all of the multiple protrusions 83U are in contact with two adjacent protrusions 83D among the multiple protrusions 83D. In this embodiment, the side 92U of the protrusion 83U is in contact with the side 93D of one protrusion 83D, and the side 93U of the protrusion 83U is in contact with the side 92D of another protrusion 83D.

[0097] All of the protrusions 83D contact two adjacent protrusions 83U among the protrusions 83U. In this embodiment, the side 92D of the protrusion 83D contacts the side 93U of one protrusion 83U, and the side 93D of the protrusion 83D contacts the side 92U of another protrusion 83U.

[0098] Multiple protrusions 83U and 83D are arranged around the central axis Axs and press against each other circumferentially. Each protrusion 83U is positioned between two adjacent protrusions 83D. Similarly, each protrusion 83D is positioned between two adjacent protrusions 83U. Thus, the base plate 55U and base plate 55D are mounted to each other through the contact between the multiple protrusions 83U and the multiple protrusions 83D. That is, the multiple protrusions 83U and 83D are riveted together and also riveted to the arm 42.

[0099] like Figure 2As shown, the dummy block 37U has a base plate 55U. The base plate 55U of the dummy block 37U is the same as the base plate 55U of the HGA36U. In addition, the dummy block 37U may also have other components such as the load-bearing beam 56.

[0100] The dummy block 37D has a base plate 55D. The base plate 55D of the dummy block 37D is the same as the base plate 55D of the HGA36D. In addition, the dummy block 37D may also have other components such as the load-bearing beam 56.

[0101] The following describes an example of the riveting method for the substrate plates 55U and 55D, which are part of the manufacturing method of HDD10. However, the riveting method for the substrate plates 55U and 55D is not limited to the following method, and other methods may also be used.

[0102] First, the bosses 62U of the base plate 55U and 62D of the base plate 55D are inserted into the riveting holes 45 of the arm 42. As a result, multiple protrusions 83U are inserted into multiple slots S2, and multiple protrusions 83D are inserted into multiple slots S1.

[0103] Before riveting, the diameter of the outer peripheral surface 91U of the plurality of protrusions 83U is smaller than the diameter of the inner surface 45a of the arm 42. Additionally, before riveting, the diameter of the outer peripheral surface 91D of the plurality of protrusions 83D is smaller than the diameter of the inner surface 45a. Therefore, before riveting, at least a portion of the bosses 62U, 62D are separated from the inner surface 45a.

[0104] Furthermore, prior to riveting, the circumferential distance between two adjacent protrusions 83U is greater than the circumferential length of each of the protrusions 83D. Therefore, prior to riveting, each protrusion 83D is separated from at least one of the two adjacent protrusions 83U among the protrusions 83U.

[0105] Before riveting, the circumferential distance between two adjacent protrusions 83D is greater than the circumferential length of each protrusion 83U in the plurality of protrusions 83U. Therefore, before riveting, each protrusion 83U in the plurality of protrusions 83U is separated from at least one of the two adjacent protrusions 83D in the plurality of protrusions 83D.

[0106] Next, the ball passes through the riveting hole 45 and the through holes 82U and 82D. The ball is made of stainless steel, for example. The rigidity of the ball is higher than that of the multiple protrusions 83U and also higher than that of the multiple protrusions 83D.

[0107] The ball bearings enter the riveting hole 45 through the through-hole 82U. The ball bearings press the plurality of protrusions 83U and 83D radially outward. As a result, each of the plurality of protrusions 83U is plastically deformed in such a way that it contacts the inner surface 45a of the arm 42 and two adjacent protrusions 83D. Similarly, each of the plurality of protrusions 83D is plastically deformed in such a way that it contacts the inner surface 45a and two adjacent protrusions 83U. Thus, the arm 42, the base plate 55U, and the base plate 55D are joined together. The ball bearings exit the riveting hole 45 through the through-hole 82D.

[0108] In the first embodiment described above, the HDD 10 includes a plurality of disks 12, an HGA 36U, a substrate 55D, and a carriage 35. The HGA 36U has a read / write head 51 configured to read and write information to one of the plurality of disks 12, and a substrate 55U. The carriage 35 has an arm 42 located between two substrates 55U and 55D, which is rotatable. The arm 42 is provided with a riveting hole 45 and has an inner surface 45a that defines the riveting hole 45. The substrate 55U has a flat surface 81U and a plurality of protrusions 83U. The flat surface 81U faces the arm 42. The plurality of protrusions 83U protrude from the flat surface 81U, contact the inner surface 45a, and are thus mounted to the arm 42. The substrate 55D has a flat surface 81D and a plurality of protrusions 83D. The flat surface 81D faces the arm 42. The plurality of protrusions 83D protrude from the flat surface 81D, contact the inner surface 45a, and are thus mounted to the arm 42. A plurality of protrusions 83U are arranged such that at least one of a plurality of protrusions 83D is disposed between two adjacent protrusions 83U. A plurality of protrusions 83D are arranged such that at least one of a plurality of protrusions 83U is disposed between two adjacent protrusions 83D. The base plate 55U and the base plate 55D are mounted to each other through mutual contact between the plurality of protrusions 83U and the plurality of protrusions 83D.

[0109] Each of the plurality of protrusions 83U is located between two adjacent protrusions 83D and can contact the inner surface 45a. Similarly, each of the plurality of protrusions 83D is located between two adjacent protrusions 83U and can contact the inner surface 45a. Therefore, the arm 42 can accommodate the plurality of protrusions 83U and 83D in a common portion (e.g., central C) of the riveting hole 45, thereby reducing the thickness. Thus, the HDD 10 can reduce the gap between two adjacent disks 12, thereby allowing for the mounting of more disks 12. Due to the increased number of disks 12, the storage capacity of the HDD 10 increases.

[0110] Furthermore, compared to a situation where multiple protrusions 83U and multiple protrusions 83D are separate from each other, HDD10 can enhance the bonding between arm 42, base plate 55U, and base plate 55D. Therefore, HDD10 can more securely mount base plate 55U and base plate 55D to arm 42. HDD10 can also prevent base plate 55U and 55D from detaching from arm 42, for example, under impact or during high-speed rotation of carriage 35.

[0111] Multiple protrusions 83U are arranged around the central axis Axs of the riveting hole 45. Multiple protrusions 83D are also arranged around the central axis Axs. That is, the multiple protrusions 83U and multiple protrusions 83D are arranged in a ring (without joints). Therefore, all the protrusions 83U and all the protrusions 83D can contact each other. Therefore, compared with the case where the multiple protrusions 83U and multiple protrusions 83D are arranged in a line, the HDD10 can further increase the contact of the multiple protrusions 83U and multiple protrusions 83D, thereby enhancing the bonding of the arm 42, the base plate 55U, and the base plate 55D.

[0112] Each of the plurality of protrusions 83U has a circumferential orientation about the central axis Axs and contacts a side surface 92U of one of the plurality of protrusions 83D. Each of the plurality of protrusions 83D has a circumferential orientation and contacts a side surface 92D of one of the plurality of protrusions 83U. Therefore, a circumferential force acts between two adjacent protrusions 83U, 83D. Thus, HDD10 can enhance the bonding between the plurality of protrusions 83U and the plurality of protrusions 83D.

[0113] Multiple protrusions 83U contact the inner surface 45a at a central point C along the central axis Axs, or closer to the plane 81D than this central point C. Multiple protrusions 83D contact the inner surface 45a at a central point C along the central axis Axs, or closer to the plane 81U than this central point C. Thus, the multiple protrusions 83U and 83D can overlap around the central axis Axs. Therefore, the HDD10 can enhance the bonding between the multiple protrusions 83U and 83D.

[0114] A through hole 82U communicating with the riveting hole 45 is provided in the base plate 55U. Multiple protrusions 83U are arranged around the through hole 82U. A through hole 82D communicating with the riveting hole 45 is provided in the base plate 55D. Multiple protrusions 83D are arranged around the through hole 82D. That is, the multiple protrusions 83U and multiple protrusions 83D are arranged in a ring (without joints). Therefore, all the protrusions 83U and all the protrusions 83D can contact each other. Therefore, compared to the case where the multiple protrusions 83U and multiple protrusions 83D are arranged in a line, the HDD10 can further increase the contact between the multiple protrusions 83U and multiple protrusions 83D, thereby enhancing the bonding of the arm 42, the base plate 55U, and the base plate 55D.

[0115] Multiple protrusions 83U and multiple protrusions 83D are arranged alternately. All of the multiple protrusions 83U are in contact with two adjacent protrusions 83D. Therefore, compared with the case where more than two protrusions 83U are arranged between two adjacent protrusions 83D, the HDD10 can further increase the contact between the multiple protrusions 83U and the multiple protrusions 83D, thereby enhancing the bonding of the arm 42, the substrate 55U, and the substrate 55D.

[0116] The number of disks 12 is twelve or more. The size of the HDD 10 is limited by standards, for example. In the field of HDD technology, the Small Form Factor Committee has established SFF-8300 as the form factor for a 3.5-inch HDD. SFF-8300 sets several maximum sizes for HDDs. Therefore, if the HDD 10 is equipped with twelve or more disks 12, the gap between two adjacent disks 12 will become smaller. However, the HDD 10 of this embodiment can reduce the thickness of the arm 42 to allow access to this small gap.

[0117] (Second Implementation)

[0118] Hereinafter, regarding the second embodiment, refer to Figure 6 The following description of various embodiments will be provided. Furthermore, in the following descriptions of multiple embodiments, components having the same function as those already described are sometimes labeled with the same reference numerals as the already described components, and their descriptions are omitted. Additionally, multiple components labeled with the same reference numerals are not limited to having all common functions and properties; they may also have different functions and properties corresponding to each embodiment.

[0119] Figure 6 This is a partial sectional view illustrating an example of the arm 42 and the base plates 55U and 55D according to the second embodiment. Figure 6As shown, in the second embodiment, the bosses 62U and 62D are replaced by a plurality of protrusions 200U and 200D instead of a plurality of protrusions 83U and 83D. The protrusions 200U and 200D are substantially the same as the protrusions 83U and 83D, except for the points to be explained below.

[0120] For the protrusion 200U, instead of the sides 92U and 93U, it has end faces 201U, 202U, side faces 203U, 204U, an outer surface 205U, and an inner surface 206U. End face 201U is an example of a first end face. Side face 203U is an example of a first side face. Outer surface 205U is an example of a first outer surface.

[0121] End face 201U is the end face of the protrusion 200U on the first circumferential direction Dc1. End face 201U is formed to be generally flat and faces the first circumferential direction Dc1. End face 202U is the end face of the protrusion 200U on the second circumferential direction Dc2. End face 202U is formed to be generally flat and faces the second circumferential direction Dc2.

[0122] Side surface 203U is closer to the inner surface 45a of arm 42 than end face 201U, and moves away from end face 201U toward the second circumferential direction Dc2. Side surface 203U is formed to be generally flat, facing the first circumferential direction Dc1. Furthermore, both end face 201U and side surface 203U may not be planar if they are oriented toward the first circumferential direction Dc1 as a whole.

[0123] Side surface 204U is further away from the inner surface 45a of arm 42 than end face 202U, and moves away from end face 202U toward the first circumferential direction Dc1. Side surface 204U is formed to be generally flat, facing toward the second circumferential direction Dc2. Furthermore, end face 202U may not be planar if it is entirely facing toward the second circumferential direction Dc2.

[0124] The outer surface 205U is located between the radially outer edge of the end face 201U and the radially inner edge of the side face 203U. The outer surface 205U is a curved surface extending about the central axis Axs and facing radially outward. That is, the outer surface 205U faces the inner surface 45a of the arm 42.

[0125] The inner surface 206U is located between the radially inner edge of the end face 202U and the radially outer edge of the side face 204U. The inner surface 206U is a curved surface extending about the central axis Axs and facing radially inward. The inner surface 206U is located on the opposite side of the outer peripheral surface 91U.

[0126] For protrusion 200D, instead of sides 92D and 93D, it has end faces 201D and 202D, side faces 203D and 204D, an outer surface 205D, and an inner surface 206D. End face 201D is an example of a second end face. Side face 203D is an example of a second side face. Outer surface 205D is an example of a second outer surface.

[0127] End face 201D is the end face of the protrusion 200D on the first circumferential direction Dc1. End face 201D is formed to be generally flat and faces the first circumferential direction Dc1. End face 202D is the end face of the protrusion 200D on the second circumferential direction Dc2. End face 202D is formed to be generally flat and faces the second circumferential direction Dc2.

[0128] Side surface 203D is closer to the inner surface 45a of arm 42 than end face 201D, and moves away from end face 201D toward the second circumferential direction Dc2. Side surface 203D is formed to be generally flat, facing the first circumferential direction Dc1. Furthermore, for end face 201D and side surface 203D, if they are both oriented toward the first circumferential direction Dc1, they may not be planar.

[0129] Side surface 204D is further away from the inner surface 45a of arm 42 than end face 202D, and moves away from end face 202D toward the first circumferential direction Dc1. Side surface 204D is formed to be generally flat, facing toward the second circumferential direction Dc2. Furthermore, end face 202D may not be planar if it is entirely facing toward the second circumferential direction Dc2.

[0130] The outer surface 205D is located between the radially outer edge of the end face 201D and the radially inner edge of the side face 203D. The outer surface 205D is a curved surface extending about the central axis Axs and facing radially outward. That is, the outer surface 205D faces the inner surface 45a of the arm 42.

[0131] The inner surface 206D is located between the radially inner edge of the end face 202D and the radially outer edge of the side face 204D. The inner surface 206D is a curved surface extending about the central axis Axs and facing radially inward. The inner surface 206D is located on the opposite side of the outer peripheral surface 91D.

[0132] End face 201U is in contact with side face 204D. End face 202U is in contact with side face 203D. Side face 203U is in contact with end face 202D. Side face 204U is in contact with end face 201D. Therefore, multiple protrusions 200U and 200D push against each other in the circumferential direction.

[0133] The portion 210U between the outer peripheral surface 91U and the inner surface 206U of the protrusion 200U is disposed between the outer surface 205D of the protrusion 200D and the inner surface 45a of the arm 42. The inner surface 206U and the outer surface 205D are in contact with each other. The protrusion 200D presses the portion 210U against the inner surface 45a.

[0134] The portion 210D of the protrusion 200D between the outer peripheral surface 91D and the inner surface 206D is disposed between the outer surface 205U of the protrusion 200U and the inner surface 45a of the arm 42. The outer surface 205U and the inner surface 206D are in contact with each other. The protrusion 200U presses the portion 210D against the inner surface 45a.

[0135] As described above, at least one of the end face 201U, the side face 203U, and the outer surface 205U of the protrusion 200U contacts the protrusion 200D. In addition, at least two of the end face 201U, the side face 203U, and the outer surface 205U can also be separated from the protrusion 200D.

[0136] At least one of the end face 201D, the side face 203D, and the outer surface 205D of the protrusion 200D contacts the protrusion 200U. In addition, at least two of the end face 201D, the side face 203D, and the outer surface 205D can also be separated from the protrusion 200U.

[0137] In the HDD10 of the second embodiment described above, each of the plurality of protrusions 200U has a circumferential end face 201U about the central axis Axs, a circumferentially facing side face 203U, and an outer surface 205U disposed between the end face 201U and the side face 203U and facing the inner surface 45a. At least one of the end face 201U, the side face 203U, and the outer surface 205U of each of the plurality of protrusions 200D contacts one of the plurality of protrusions 200D. Each of the plurality of protrusions 200D has a circumferentially facing end face 201D, a circumferentially facing side face 203D, and an outer surface 205D disposed between the end face 201D and the side face 203D and facing the inner surface 45a. At least one of the end face 201D, the side face 203D, and the outer surface 205D of the plurality of protrusions 200D contacts one of the plurality of protrusions 200U. Therefore, at least one of the circumferential force and the radial force acts between adjacent protrusions 200U and 200D. The HDD10 can enhance the bonding between the plurality of protrusions 200U and 200D through this circumferential force. Furthermore, the HDD10 can enhance the bonding between the arm 42, the base plate 55U, and the base plate 55D by pressing one of the protrusions 200U and 200D against the inner surface 45a in another direction through this radial force.

[0138] Multiple protrusions 200U are each partially disposed between the outer surface 205D and the inner surface 45a, with at least one of the protrusions 200D contacting the outer surface 205D. Multiple protrusions 200D are each partially disposed between the outer surface 205D and the inner surface 45a, with at least one of the protrusions 200U contacting the outer surface 205D. Thus, a radial force acts between adjacent protrusions 200U and 200D. HDD10 uses this radial force to press one of the protrusions 200U and 200D against the inner surface 45a in the other direction, thereby enhancing the bonding between the arm 42, the base plate 55U, and the base plate 55D.

[0139] (Third Implementation)

[0140] Hereinafter, regarding the third embodiment, refer to Figure 7 Please provide an explanation. Figure 7 This is a partial sectional view illustrating an example of the arm 42 and the base plates 55U and 55D according to the third embodiment. Figure 7 As shown, in the third embodiment, the boss 62U has multiple protrusions 301U and one protrusion 302U instead of multiple protrusions 83U. The protrusions 301U and 302U are substantially the same as the protrusions 83U, except for the points to be explained below. Furthermore, the boss 62U may also have multiple protrusions 301U and omit the protrusion 302U.

[0141] Each of the multiple protrusions 301U has a slope 311U or 312U instead of the sides 92U and 93U. Slope 311U is an example of the first slope.

[0142] The inclined surface 311U is the end face of the protrusion 301U on the first circumferential direction Dc1. The inclined surface 311U is formed to be generally flat, oriented in the direction of inclination between the first circumferential direction Dc1 and the radially outward direction. In addition, the inclined surface 311U may not be flat if the whole is oriented in this inclination direction.

[0143] The inclined surface 312U is the end face of the protrusion 301U on the second circumferential direction Dc2. The inclined surface 312U is formed to be generally flat, oriented in the direction of inclination between the second circumferential direction Dc2 and the radially inward side. Alternatively, the inclined surface 312U may not be flat if the entire surface is oriented in this direction of inclination.

[0144] For protrusion 302U, instead of sides 92U and 93U, it has inclined surfaces 311U and 313U. The inclined surface 311U of protrusion 302U is substantially the same as that of protrusion 301U. Inclined surface 313U is the end face of protrusion 302U on the second circumferential direction Dc2. Inclined surface 313U is formed to be substantially flat, oriented in the direction of inclination between the second circumferential direction Dc2 and the radially outward direction. Furthermore, for inclined surface 313U, if the entire surface is oriented in this direction of inclination, it may also be non-flat.

[0145] Each of the multiple protrusions 301D has a ramp 311D or 312D instead of the sides 92D and 93D. The ramp 311D is an example of the second ramp.

[0146] The inclined surface 311D is the end face of the protrusion 301D on the first circumferential direction Dc1. The inclined surface 311D is formed to be generally flat, oriented in the direction of inclination between the first circumferential direction Dc1 and the radially outward direction. Alternatively, the inclined surface 311D may not be flat if the entire surface is oriented in this direction of inclination.

[0147] The inclined surface 312D is the end face of the protrusion 301D on the second circumferential direction Dc2. The inclined surface 312D is formed to be generally flat, oriented in the direction of inclination between the second circumferential direction Dc2 and the radially inward side. Alternatively, the inclined surface 312D may not be flat if the entire surface is oriented in this direction of inclination.

[0148] For protrusion 302D, instead of sides 92D and 93D, it has inclined surfaces 313D and 312D. The inclined surface 312D of protrusion 302D is substantially the same as that of protrusion 301D. Inclined surface 313D is the end face of protrusion 302D on the first circumferential direction Dc1. Inclined surface 313D is formed to be substantially flat, oriented towards the direction of inclination between the second circumferential direction Dc2 and the radially inward side. Furthermore, for inclined surface 313D, if the entire surface is oriented towards this inclination direction, it may also be non-flat.

[0149] One of the protrusions 301U has an inclined surface 311U in contact with the inclined surface 312D of protrusion 302D. One of the protrusions 301D has an inclined surface 312D in contact with the inclined surface 311U of protrusion 302U. The inclined surface 313U of protrusion 302U is in contact with the inclined surface 313D of protrusion 302D.

[0150] The remaining inclined surfaces 311U of the plurality of protrusions 301U are in contact with the remaining inclined surfaces 312D of the plurality of protrusions 301D. The remaining inclined surfaces 312U of the plurality of protrusions 301U are in contact with the remaining inclined surfaces 311D of the plurality of protrusions 301D.

[0151] The inclined surfaces 311U of the multiple protrusions 301U and 302U press the multiple protrusions 301D and 302D circumferentially and against the inner surface 45a of the arm 42. The inclined surfaces 311D of the multiple protrusions 301D press the multiple protrusions 301U circumferentially and against the inner surface 45a of the arm 42.

[0152] When bosses 62U and 62D are riveted to rivet holes 45, it is possible that the inclined surface 311U presses protrusions 301D and 302D toward the first circumferential direction Dc1. Additionally, it is possible that the inclined surface 311D presses protrusion 301U toward the first circumferential direction Dc1. However, the inclined surface 313U of protrusion 302U presses protrusion 302D toward the second circumferential direction Dc2. Therefore, it is possible to suppress the possibility that the base plates 55U and 55D will rotate relative to arm 42 toward the first circumferential direction Dc1.

[0153] In the HDD10 of the third embodiment described above, each of the plurality of protrusions 301U has a slope 311U. The slope 311U faces the direction between the radially outer side orthogonal to the central axis Axs and the circumferential direction around the central axis Axs, and contacts one of the plurality of protrusions 301D. Each of the plurality of protrusions 301D has a slope 311D. The slope 311D faces the direction between the radially outer side and the circumferential direction, and contacts one of the plurality of protrusions 301U. Therefore, the protrusion 301U presses the protrusion 301D circumferentially and against the inner surface 45a. In addition, the protrusion 301D presses the protrusion 301U circumferentially and against the inner surface 45a. Therefore, the HDD10 can enhance the bonding of the arm 42, the substrate 55U, and the substrate 55D.

[0154] Several embodiments of the present invention have been described, but these embodiments are merely illustrative and not intended to limit the scope of the invention. These novel embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and / or variations thereof are included in the scope and / or spirit of the invention and in the scope of the claims and their equivalents.

Claims

1. A disk device comprising: Multiple disks; A head universal joint assembly includes a read / write head configured to read and write information to one of the plurality of disks, and a first base plate; Second base plate; and A rotatable carriage having an arm located between the first base plate and the second base plate. The arm is provided with a first through hole, and has an inner surface defining the first through hole. The first base plate has a first surface facing the arm and a plurality of first protrusions protruding from the first surface and mounted on the arm by contacting the inner surface. The second base plate has a second surface facing the arm and a plurality of second protrusions protruding from the second surface and mounted on the arm by contacting the inner surface. The plurality of first protrusions are arranged such that at least one of the plurality of second protrusions is disposed between two adjacent first protrusions. The plurality of second protrusions are arranged such that at least one of the plurality of first protrusions is positioned between two adjacent second protrusions. The first base plate and the second base plate are mounted to each other through the plurality of first protrusions and the plurality of second protrusions in contact with each other.

2. The disk device according to claim 1, The plurality of first protrusions are arranged around the central axis of the first through hole. The plurality of second protrusions are arranged around the central axis.

3. The disk device according to claim 2, Each of the plurality of first protrusions has a first side facing circumferentially about the central axis and in contact with one of the plurality of second protrusions. Each of the plurality of second protrusions has a second side facing the circumferential direction and in contact with one of the plurality of first protrusions.

4. The disk device according to claim 2, Each of the plurality of first protrusions has a first end face circumferentially about the central axis, a first side face facing the circumferential direction, and a first outer surface disposed between the first end face and the first side face and facing the inner surface. At least one of the first end face, the first side face, and the first outer surface contacts one of the plurality of second protrusions. Each of the plurality of second protrusions has a second end face in the circumferential direction, a second side face facing the circumferential direction, and a second outer surface disposed between the second end face and the second side face and facing the inner surface. At least one of the second end face, the second side face, and the second outer surface contacts one of the plurality of first protrusions.

5. The disc device according to claim 4, Each of the plurality of first protrusions is partially disposed between the second outer surface and the inner surface, and at least one of the plurality of second protrusions is in contact with the first outer surface. Each of the plurality of second protrusions is partially disposed between the first outer surface and the inner surface, and at least one of the plurality of first protrusions is in contact on the second outer surface.

6. The disk device according to claim 2, Each of the plurality of first protrusions has a first inclined surface that faces a direction between a radially outward direction orthogonal to the central axis and a circumferential direction about the central axis, and contacts one of the plurality of second protrusions. Each of the plurality of second protrusions has a second inclined surface that faces toward the radially outward and circumferential direction and contacts one of the plurality of first protrusions.

7. The disk device according to claim 2, The plurality of first protrusions are in contact with the inner surface at a position at or near the second surface along the axial direction of the central axis. The plurality of second protrusions are in contact with the inner surface at the center of the inner surface in the axial direction, or at a position closer to the first surface than the center.

8. The disk device according to claim 1, The first base plate is provided with a second through hole that communicates with the first through hole. The plurality of first protrusions are arranged around the second through hole. A third through hole communicating with the first through hole is provided in the second base plate. The plurality of second protrusions are arranged around the third through hole.

9. The disc device according to any one of claims 1 to 8, The plurality of first protrusions and the plurality of second protrusions are arranged alternately. All of the plurality of first protrusions are in contact with two adjacent second protrusions among the plurality of second protrusions.

10. The disk device according to claim 1, The number of disks is 12 or more.

Images