Disk device

Abstract

Provided is a disk device capable of improving the bonding strength between an end surface of a base and a housing. A disk device according to an embodiment includes a magnetic disk, a base, a film, an inner cover, and an outer cover. The base body is provided with an internal space; the magnetic disk includes a first inner surface surrounding the magnetic disk, a support surface connected to an end of the first inner surface in a first direction, a second inner surface farther from a rotation axis of the magnetic disk than the first inner surface and connected to the support surface, and an end surface connected to an end of the second inner surface in the first direction. The film covers a covered region in the second inner surface, and is separated from the end surface and an exposed region in the second inner surface, the exposed region being aligned with the covered region around the rotation axis. The inner cover is supported by the support surface and surrounded by the second inner surface. And the outer cover is combined with at least one part of the base body.

Description

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2024-031333 (filing date: March 1, 2024), the entire contents of which are incorporated herein by reference. Technical Field

[0002] An embodiment of the present invention relates to a disk device. Background Art

[0003] A disk device such as a hard disk drive (HDD) includes a magnetic disk and a housing that accommodates the magnetic disk. The housing includes, for example, a base, an inner cover that closes the interior space of the base, and an outer cover that covers the inner cover and is welded to an end surface of the base.

[0004] The surface of the substrate is generally protected by an electrodeposition coating. On the other hand, to prevent melting of this coating during welding, the substrate is sometimes removed near the cover, for example by cutting. If the width of the substrate's end face is reduced by cutting, the weld strength between the end face and the cover may be reduced. Summary of the Invention

[0005] An embodiment of the present invention provides a disk device capable of improving the bonding strength between an end surface of a base and a cover.

[0006] Means for solving problems

[0007] The disk drive of this embodiment includes a magnetic disk, a base, a film, an inner cover, and an outer cover. The magnetic disk is rotatable about a rotation axis. The base is provided with an internal space for accommodating the magnetic disk, and has a first inner surface surrounding the magnetic disk, a supporting surface connected to the end of the first inner surface in a first direction along the rotation axis, a second inner surface farther from the rotation axis than the first inner surface and connected to the supporting surface, and an end surface connected to the end of the second inner surface in the first direction. The film covers at least a portion of the first inner surface, at least a portion of the supporting surface, and a covered area of ​​the second inner surface, and is separated from the end surface and an exposed area of ​​the second inner surface aligned with the covered area about the rotation axis. The inner cover is supported by the supporting surface, surrounded by the second inner surface, and covers the internal space. The outer cover is coupled to at least a portion of the base and covers the inner cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is an illustrative perspective view showing an HDD according to one embodiment.

[0009] Figure 2 This is an exemplary plan view schematically showing a portion of the HDD according to the above embodiment.

[0010] Figure 3 A portion of the HDD of the above embodiment is connected along Figure 2 An exemplary cross-sectional view is shown along line F3-F3.

[0011] Description of Reference Numerals

[0012] 10…hard disk drive (HDD), 12…magnetic disk, 21…substrate, 22…paint film, 23…inner cover, 24…gasket, 25…outer cover, 51…first inner surface, 52…second inner surface, 53…support surface, 54…end surface, 55…inclined surface, 56…first outer surface, 57…second outer surface, 71, 71A, 71B, 71C…coated area, 72, 72A, 72B, 72C…exposed area, 83…side surface, 84, 84A, 84B, 84C…convex portion, 91, 91A, 91B, 91C…rough portion, 92, 92A, 92B, 92C…thin portion, Si…internal space, Axd…center axis, P1, P2, P3…ends, D1, D2, D3, D4…distance, L1, L2…length, W1, W2…width. DETAILED DESCRIPTION

[0013] Below, refer to Figures 1 to 3 An embodiment is described. Furthermore, in this specification, components of an embodiment and descriptions of those components may be described using multiple expressions. These components and their descriptions are examples and are not limited to the descriptions in this specification. Components may also be identified by names different from those in this specification. Furthermore, components may also be described using expressions different from those in this specification.

[0014] In the following description, “suppress” is defined as, for example, preventing a phenomenon, action, or influence from occurring, or reducing the degree of a phenomenon, action, or influence.

[0015] Figure 1 It is an illustrative perspective view showing a hard disk drive (HDD) 10 according to the present embodiment. Figure 2 This is an exemplary plan view schematically showing a part of the HDD 10 according to the present embodiment.

[0016] Figure 3 A portion of the HDD 10 of this embodiment is connected along Figure 2 An exemplary cross-sectional view is shown along line F3-F3.

[0017] As shown in the figures, in this specification, for convenience, the X-axis, Y-axis, and Z-axis are defined. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis is located along the width of the HDD 10. The Y-axis is located along the length of the HDD 10. The Z-axis is located along the thickness of the HDD 10.

[0018] In this specification, the X, Y, and Z directions are defined. The X direction is a direction along the X-axis, including the +X direction indicated by the X-axis arrow and the -X direction, which is the opposite direction of the X-axis arrow. The Y direction is a direction along the Y-axis, including the +Y direction indicated by the Y-axis arrow and the -Y direction, which is the opposite direction of the Y-axis arrow. The Z direction is a direction along the Z-axis, including the +Z direction indicated by the Z-axis arrow and the -Z direction, which is the opposite direction of the Z-axis arrow.

[0019] like Figure 1 As shown, the HDD 10 has a housing 11, a plurality of magnetic disks 12, a spindle motor 13, a head stack assembly (HSA) 14, and a voice coil motor (VCM) 15. The magnetic disks 12 may also be referred to as disks or platters.

[0020] like Figure 3 As shown, the housing 11 includes a base 21, a paint film 22, an inner cover 23, a gasket 24, and an outer cover 25. However, the housing 11 is not limited to this example. The paint film 22 is an example of a film. Figure 1 For the sake of convenience, the housing 11 is shown with the inner cover 23 , the gasket 24 , and the outer cover 25 omitted. Figure 2 For convenience, the outer cover 25 is virtually shown by a two-dot chain line.

[0021] The base 21, the inner cover 23, and the outer cover 25 are each made of a metal material such as aluminum alloy. In addition, the base 21, the inner cover 23, and the outer cover 25 may be made of different materials.

[0022] The base 21 is formed into a substantially rectangular box shape that is open in the +Z direction. Specifically, an internal space Si is provided in the base 21. The internal space Si communicates with the exterior of the base 21 via the end of the base 21 in the +Z direction. Multiple magnetic disks 12, the spindle motor 13, the HSA 14, and the VCM 15 are disposed in the internal space Si.

[0023] like Figure 1 As shown, the base 21 extends in the Y direction (+Y direction and -Y direction). Therefore, the Y direction is the longitudinal direction of the base 21 and the housing 11. The X direction is the transverse direction of the base 21 and the housing 11.

[0024] The base 21 has a bottom wall 31 and side walls 32. The bottom wall 31 is formed into a substantially rectangular (quadrilateral) plate arranged substantially perpendicular to the Z direction. The side walls 32 protrude from the edge of the bottom wall 31 in the substantially +Z direction and are formed into a substantially rectangular frame shape.

[0025] The coating film 22 is made of, for example, epoxy resin. However, the coating film 22 is not limited to this example. The coating film 22 is applied to the surface of the substrate 21 by, for example, electrodeposition coating. The coating film 22 has higher corrosion resistance and rust resistance than the substrate 21, and protects the substrate 21.

[0026] like Figure 2 As shown, the inner cover 23 is mounted on the side wall 32 by a fastening member 35 such as a screw. Thus, the inner cover 23 covers the inner space Si of the base 21. Figure 3 As shown, a gasket 24 is interposed between the sidewall 32 and the inner cover 23, sealing the gap between the sidewall 32 and the inner cover 23. The outer cover 25 covers the inner cover 23 and is attached to the sidewall 32, for example, by welding. Furthermore, the outer cover 25 may be bonded to other portions of the base 21. Specifically, the outer cover 25 is bonded to at least a portion of the base 21.

[0027] For example, the inner cover 23 and the outer cover 25 are provided with ventilation holes. After the magnetic disk 12, spindle motor 13, HSA 14, and VCM 15 are arranged in the internal space Si and the inner cover 23 and outer cover 25 are attached to the base 21, the air inside the housing 11 is exhausted through the ventilation holes. Furthermore, the internal space Si is filled with a gas different from air. The ventilation holes of the outer cover 25 are hermetically sealed, for example, with a sealant.

[0028] The gas filled in the internal space Si is, for example, a low-density gas having a lower density than air, an inert gas having low reactivity, etc. For example, helium is filled in the internal space Si. Alternatively, other fluids may be filled in the internal space Si.

[0029] The plurality of magnetic disks 12 are arranged with gaps therebetween in the Z direction. The plurality of magnetic disks 12 are formed into disk shapes arranged substantially perpendicular to the Z direction. The diameter of each of the plurality of magnetic disks 12 is, for example, 96 mm or greater. However, the diameter of the magnetic disks 12 is not limited to this example.

[0030] Each of the multiple magnetic disks 12 has two flat surfaces 12a and 12b and an outer peripheral surface 12c. Flat surface 12a is oriented approximately in the +Z direction. Flat surface 12b is located opposite flat surface 12a and faces approximately in the -Z direction. Outer peripheral surface 12c is a generally cylindrical curved surface extending approximately in the Z direction between the outer edges of flat surface 12a and flat surface 12b. Magnetic recording layers are provided on flat surfaces 12a and 12b.

[0031] Figure 1 The spindle motor 13 supports the plurality of magnetic disks 12. The plurality of magnetic disks 12 are held on the hub of the spindle motor 13 by, for example, a circlip. The spindle motor 13 rotates the plurality of magnetic disks 12 integrally around a central axis Axd. The central axis Axd is an example of a rotation axis.

[0032] The central axis Axd is a virtual axis extending substantially in the Z direction. The central axis Axd is, for example, the central axis of the magnetic disk 12 and the spindle motor 13. The central axis Axd is not limited to this example.

[0033] The HSA 14 includes a carriage 41 and multiple head gimbal assemblies (HGAs) 42. The HSA 14 is not limited to this example. The carriage 41 is rotatably mounted on the base 21 about a central axis Axc. The central axis Axc is a virtual axis extending generally in the Z direction. Specifically, the central axis Axc of the carriage 41 extends generally parallel to the central axis Axd of the magnetic disk 12. The central axis Axc is spaced apart from the central axis Axd.

[0034] The HGAs 42 are mounted on the arms of the carriage 41 and rotate integrally with the carriage 41 around the central axis Axc. The HGAs 42 are arranged with gaps therebetween in the Z direction. Each of the HGAs 42 includes a magnetic head 45. The magnetic head 45 may also be referred to as a slider.

[0035] The magnetic head 45 records and reproduces information on a corresponding magnetic disk 12. In other words, the magnetic head 45 reads and writes information on the magnetic disk 12. The carriage 41 rotates about the central axis Axc to move the magnetic head 45 relative to the corresponding magnetic disk 12.

[0036] The VCM 15 moves the magnetic head 45 to a desired position along the magnetic disk 12 by rotating the carriage 41 about the central axis Axc. The VCM 15 includes a voice coil, a pair of yokes, and magnets provided on the yokes.

[0037] like Figure 3 As shown, the side wall 32 has a first inner surface 51, a second inner surface 52, a support surface 53, an end surface 54, an inclined surface 55, a first outer surface 56, and a second outer surface 57. The second outer surface 57 is an example of an outer surface.

[0038] The first inner surface 51, the second inner surface 52, the support surface 53, the end surface 54, the inclined surface 55, the first outer surface 56, and the second outer surface 57 are each formed into a frame shape surrounding the central axes Axc and Axd. The first inner surface 51 and the second inner surface 52 face a direction substantially perpendicular to the central axis Axd. Furthermore, at least a portion of the first inner surface 51 and the second inner surface 52 may face other directions.

[0039] The first inner surface 51 extends from the bottom wall 31 in a generally positive Z direction. The first inner surface 51 surrounds the plurality of magnetic disks 12, at least a portion of the spindle motor 13, at least a portion of the HSA 14, and at least a portion of the VCM 15. Specifically, in the Z direction, the plurality of magnetic disks 12 are arranged between the ends of the first inner surface 51 in the positive Z direction and the ends of the first inner surface 51 in the negative Z direction. Alternatively, a portion of the magnetic disks 12 may protrude in the positive Z direction beyond the ends of the first inner surface 51 in the positive Z direction.

[0040] The first inner surface 51 has a curved surface 51a. The curved surface 51a is a substantially cylindrical curved surface extending along the outer peripheral surface 12c of the magnetic disk 12. In other words, the curved surface 51a of the first inner surface 51 and the outer peripheral surface 12c of the magnetic disk 12 are concentrically (coaxially) arranged.

[0041] The curved surface 51 a functions as a so-called shroud and thus suppresses the generation of turbulent helium flow by regulating the flow of helium in the internal space Si near the magnetic disk 12 .

[0042] The second inner surface 52 is further away from the bottom wall 31 than the first inner surface 51. Moreover, the second inner surface 52 is further away from the central axes Axc and Axd than the first inner surface 51. Figure 2 In the projection surface viewed in the Z direction (+Z direction or -Z direction), the second inner surface 52 surrounds the first inner surface 51. The +Z direction is a direction along the central axis Axd and is an example of the first direction.

[0043] like Figure 3 As shown, the support surface 53 and the end surface 54 face substantially in the +Z direction. Furthermore, projections and depressions may be provided on the support surface 53 and the end surface 54. That is, at least a portion of the support surface 53 and the end surface 54 may face other directions.

[0044] The support surface 53 connects the end of the first inner surface 51 in the +Z direction and the end of the second inner surface 52 in the -Z direction. In other words, the support surface 53 is provided between the first inner surface 51 and the second inner surface 52. The support surface 53 supports the inner cover 23 via the gasket 24. In other words, the gasket 24 is interposed between the support surface 53 and the inner cover 23.

[0045] The second inner surface 52 surrounds the inner cover 23 and the gasket 24, which are supported by the support surface 53. Specifically, the inner cover 23 and the gasket 24 are positioned between the ends of the second inner surface 52 in the +Z direction and the ends of the second inner surface 52 in the -Z direction. Furthermore, a portion of the inner cover 23 may protrude in the +Z direction beyond the end of the second inner surface 52 in the +Z direction, and a portion of the gasket 24 may protrude in the -Z direction beyond the end of the second inner surface 52 in the -Z direction.

[0046] The first inner surface 51 is provided in the inner space Si. In other words, the bottom wall 31 and the first inner surface 51 form (define, partition) the inner space Si. The second inner surface 52 is provided in the intermediate space Sm between the inner cover 23 and the outer cover 25. The support surface 53 may be provided partially in the inner space Si or partially in the intermediate space Sm.

[0047] The end surface 54 is connected to the end of the second inner surface 52 in the +Z direction. The end surface 54 is provided at the end of the side wall 32 in the +Z direction. In addition, the side wall 32 may have another portion located at the end of the side wall 32 in the +Z direction.

[0048] The outer cover 25 is joined to the end surface 54 by welding, for example. Therefore, a weld bead 58 is provided on the end surface 54. The weld bead 58 extends along the end surface 54. Alternatively, the outer cover 25 may be joined to the end surface 54 by other methods.

[0049] The inclined surface 55 is provided between the second inner surface 52 and the end surface 54. That is, the end surface 54 is connected to the end of the second inner surface 52 in the +Z direction via the inclined surface 55. Alternatively, the end surface 54 may be directly connected to the second inner surface 52.

[0050] The inclined surface 55 extends between the second inner surface 52 and the end surface 54 at an angle relative to the second inner surface 52 and the end surface 54. The inclined surface 55 is formed by, for example, chamfering. However, the inclined surface 55 is not limited to this example.

[0051] The first outer surface 56 is located on the opposite side of the first inner surface 51 and the second inner surface 52. The second outer surface 57 is located on the opposite side of the second inner surface 52. The end of the second outer surface 57 in the +Z direction is connected to the end surface 54. The end of the second outer surface 57 in the -Z direction is connected to the first outer surface 56.

[0052] The side wall 32 includes a wall 61 and a rib 62. The wall 61 includes a portion of the first outer surface 56, the first inner surface 51, and the support surface 53. Specifically, the wall 61 protrudes from the edge of the bottom wall 31 in the approximately +Z direction. The support surface 53 is the end surface of the wall 61 in the +Z direction. The rib 62 includes the second inner surface 52, the end surface 54, a portion of the first outer surface 56, and the second outer surface 57. The rib 62 protrudes from the support surface 53 of the wall 61 in the approximately +Z direction. The cover 25 is welded to the rib 62.

[0053] like Figure 2 As shown, the second inner surface 52 has a covered area 71 and an exposed area 72. Figure 3 As shown, the second inner surface 52 further includes a lower region 73. In addition, the second inner surface 52 is not limited to this example.

[0054] like Figure 2As shown, the covered region 71 and the exposed region 72 are adjacent to each other around the central axis Axd. In other words, the covered region 71 and the exposed region 72 are arranged around the central axis Axd. The covered region 71 and the exposed region 72 are at least partially arranged at approximately the same position (height) in the Z direction.

[0055] In this embodiment, the covered region 71 includes three covered regions 71A, 71B, and 71C. However, the covered region 71 is not limited to this example. The three covered regions 71A, 71B, and 71C are separated from each other around the central axis Axd.

[0056] In this embodiment, the exposed area 72 includes three exposed areas 72A, 72B, and 72C. However, the exposed area 72 is not limited to this example. The three exposed areas 72A, 72B, and 72C are separated from each other around the central axis Axd. The exposed area 72A is an example of a first exposed area. The exposed area 72B is an example of a second exposed area. The exposed area 72C is an example of a third exposed area.

[0057] The three covered regions 71A, 71B, and 71C and the three exposed regions 72A, 72B, and 72C are alternately arranged around the central axis Axd. The exposed region 72A is located between the two covered regions 71A and 71C. The exposed region 72B is located between the two covered regions 71A and 71B. The exposed region 72C is located between the two covered regions 71B and 71C.

[0058] exist Figure 2 In the projection plane viewed in the Z direction, the exposed area 72A faces the end (apex) P1 of the magnetic disk 12 in the +Y direction. The +Y direction is a direction perpendicular to the central axis Axd and is an example of a second direction.

[0059] The center axis Axd of the magnetic disk 12 is spaced apart from the center of the base 21 in the Y direction (longitudinal direction) toward the +Y direction. That is, the magnetic disk 12 is spaced apart from the end of the base 21 in the -Y direction and approaches the end of the base 21 in the +Y direction. Meanwhile, the center axis Axc of the carriage 41 is spaced apart from the end of the base 21 in the +Y direction and approaches the end of the base 21 in the -Y direction.

[0060] In the projection plane viewed in the Z direction, the exposed area 72B faces the end P2 of the magnetic disk 12 in the +X direction. The +X direction is a direction perpendicular to the +Z direction and the +Y direction and is an example of a third direction.

[0061] In the projection plane viewed in the Z direction, the exposed area 72C faces the end P3 of the magnetic disk 12 in the -X direction. The -X direction is the opposite direction to the +X direction and is an example of the fourth direction. The two exposed areas 72B and 72C face each other.

[0062] The exposed area 72 is closer to the magnetic disk 12 than the covered area 71. For example, the exposed area 72A is the portion of the second inner surface 52 closest to the end P1 of the magnetic disk 12. The exposed area 72B is the portion of the second inner surface 52 closest to the end P2 of the magnetic disk 12. The exposed area 72C is the portion of the second inner surface 52 closest to the end P3 of the magnetic disk 12.

[0063] The distance between the exposed area 72A and the magnetic disk 12, the distance between the exposed area 72B and the magnetic disk 12, and the distance between the exposed area 72C and the magnetic disk 12 are substantially equal to each other. Alternatively, these distances may be different from each other.

[0064] like Figure 3 As shown, lower region 73 is provided between covered region 71 and support surface 53, and between exposed region 72 and support surface 53. Therefore, covered region 71 and exposed region 72 are spaced substantially apart from support surface 53 in the +Z direction. Lower region 73 is provided throughout the entire circumference of central axis Axd. However, lower region 73 is not limited to this example.

[0065] Paint film 22 covers at least a portion of first inner surface 51, at least a portion of support surface 53, first outer surface 56, coated region 71 (coated regions 71A, 71B, 71C), and at least a portion of lower region 73. In other words, paint film 22 adheres to first inner surface 51, support surface 53, first outer surface 56, coated region 71, and lower region 73.

[0066] The paint film 22 does not cover the end surface 54, the second outer surface 57, and the exposed area 72 (exposed areas 72A, 72B, and 72C), leaving them exposed. In other words, the paint film 22 is separated from the end surface 54, the second outer surface 57, and the exposed area 72. Alternatively, the end surface 54, the second outer surface 57, and the exposed area 72 may be covered by another member such as the outer cover 25.

[0067] For example, the paint film 22 provided on the second inner surface 52 is removed by cutting, thereby forming an exposed area 72 on the second inner surface 52. A portion of the second inner surface 52 is cut to form the exposed area 72, which is recessed from the covered area 71 and the lower area 73, which are the other portions. Thus, the exposed area 72 forms a recessed portion 75 that opens into the end surface 54, the covered area 71, and the lower area 73. Alternatively, the covered area 71, the exposed area 72, and the lower area 73 may form the same plane.

[0068] like Figure 2As shown, the width of the portion of the rib 62 where the exposed region 72 is provided is thinner than the width of the portion of the rib 62 where the covered region 71 is provided. That is, the distance D1 between the exposed region 72 and the second outer surface 57 is shorter than the distance D2 between the covered region 71 and the second outer surface 57. The distances D1 and D2 are not limited to this example.

[0069] like Figure 3 As shown, the length of the slope 55 between the exposed region 72 and the end face 54 is shorter than the length of the slope 55 between the covered region 71 and the end face 54. The length of the slope 55 is not limited to this example.

[0070] In the Z direction, the inner cover 23 is positioned between the ends of the exposed region 72 in the +Z direction and the ends of the exposed region 72 in the -Z direction. Therefore, the covered region 71 and the exposed region 72 face the inner cover 23. Furthermore, the inner cover 23 is further away from the support surface 53 than the ends of the exposed region 72 in the -Z direction. The -Z direction is the opposite direction to the +Z direction and is an example of a fifth direction.

[0071] The lower region 73 faces the gasket 24. In the Z direction, the lower region 73 is away from the inner cover 23 in the -Z direction. Therefore, the lower region 73 does not face the inner cover 23. The lower region 73 is not limited to this example.

[0072] The inner cover 23 has an inner surface 81 and an outer surface 82. Figure 2 As shown in FIG. 8 , the inner cover 23 further includes a side surface 83 and a convex portion 84. However, the inner cover 23 is not limited to this example. The convex portion 84 may be omitted from the inner cover 23.

[0073] like Figure 3 As shown, the inner surface 81 faces the bottom wall 31 and the support surface 53. The sealing gasket 24 is interposed between the support surface 53 and the inner surface 81. The inner surface 81 faces the interior space Si. The outer surface 82 is located on the opposite side of the inner surface 81. The outer surface 82 faces the outer cover 25.

[0074] The side surface 83 extends substantially in the Z direction between the outer edge of the inner surface 81 and the outer edge of the outer surface 82. Figure 2 As shown, the side surface 83 faces a direction substantially perpendicular to the central axis Axd. The side surface 83 faces the second inner surface 52. In this embodiment, the side surface 83 faces the paint film 22 on the coating region 71.

[0075] The protrusion 84 protrudes from the side surface 83 toward the exposed area 72. In this embodiment, the protrusion 84 includes three protrusions 84A, 84B, and 84C. However, the protrusion 84 is not limited to this example. The three protrusions 84A, 84B, and 84C are separated from each other around the central axis Axd.

[0076] The projection 84A projects from the side surface 83 toward the exposed region 72A. The projection 84B projects from the side surface 83 toward the exposed region 72B. The projection 84C projects from the side surface 83 toward the exposed region 72C.

[0077] Each of protrusions 84A, 84B, and 84C has a side surface 85. Side surfaces 85 face exposed area 72. Side surfaces 85 of protrusion 84A extend generally parallel to exposed area 72A. Side surfaces 85 of protrusion 84B extend generally parallel to exposed area 72B. Side surfaces 85 of protrusion 84C extend generally parallel to exposed area 72C.

[0078] Distance D3 between inner cover 23 and exposed area 72 is shorter than distance D4 between inner cover 23 and paint film 22. Distance D3 is at least one of the distance between side surface 85 of protrusion 84A and exposed area 72A, the distance between side surface 85 of protrusion 84B and exposed area 72B, and the distance between side surface 85 of protrusion 84C and exposed area 72C. Distance D4 is the distance between side surface 83 of inner cover 23 and paint film 22 on coated area 71.

[0079] The length L1 of the protrusion 84 about the central axis Axd is shorter than the length L2 of the exposed area 72. Length L1 is at least one of the length of the protrusion 84A in the X direction, the length of the protrusion 84B in the Y direction, and the length of the protrusion 84C in the Y direction. Length L2 is at least one of the length of the exposed area 72A in the X direction, the length of the exposed area 72B in the Y direction, and the length of the exposed area 72C in the Y direction.

[0080] The projections 84 are located outside the recesses 75 and are spaced apart from the paint film 22 and the exposed area 72. Alternatively, the projections 84 may be partially housed in the recesses 75 or may be partially in contact with the paint film 22 and the exposed area 72.

[0081] The gasket 24 is made of, for example, a synthetic rubber with low helium permeability. The gasket 24 is formed into a frame shape (without joints) surrounding the central axes Axc and Axd. The gasket 24 has a thick portion 91 and a thin portion 92. The thick portion 91 is an example of a first portion. The thin portion 92 is an example of a second portion.

[0082] exist Figure 2 In the projection plane viewed in the Z direction, the thick portion 91 is located between the magnetic disk 12 and the coating film 22. The thick portion 91 extends substantially along the side surface 83 of the inner cover 23. However, a portion of the thick portion 91 may be bent, for example, so as to bypass the fastening member 35 on the inner side.

[0083] In this embodiment, the thick portion 91 has three thick portions 91A, 91B, and 91C. Figure 2In such a projection plane, rough portion 91A is located between magnetic disk 12 and coating film 22 on coated region 71A. Rough portion 91B is located between magnetic disk 12 and coating film 22 on coated region 71B. Rough portion 91C is located between magnetic disk 12 and coating film 22 on coated region 71C. Rough portion 91 is not limited to this example.

[0084] exist Figure 2 In the projection plane viewed in the Z direction, the thin portion 92 is located between the magnetic disk 12 and the exposed area 72. The thin portion 92 is curved so as to protrude from the thick portion 91 toward the exposed area 72. The thin portion 92 extends along the side surface 85 of the convex portion 84.

[0085] In this embodiment, thin portion 92 includes three thin portions 92A, 92B, and 92C. Three thick portions 91A, 91B, and 91C and three thin portions 92A, 92B, and 92C are alternately arranged around central axis Axd. Thin portion 92A is located between two thick portions 91A and 91C. Thin portion 92B is located between two thick portions 91A and 91B. Thin portion 92C is located between two thick portions 91B and 91C.

[0086] exist Figure 2 In this projection plane, thin portion 92A is located between magnetic disk 12 and exposed area 72A and is curved so as to protrude from thick portions 91A and 91C toward exposed area 72A. In this projection plane, thin portion 92B is located between magnetic disk 12 and exposed area 72B and is curved so as to protrude from thick portions 91A and 91B toward exposed area 72B. In this projection plane, thin portion 92C is located between magnetic disk 12 and exposed area 72C and is curved so as to protrude from thick portions 91B and 91C toward exposed area 72C. Thin portion 92 is not limited to this example.

[0087] exist Figure 2 In the projection plane viewed in the Z direction, the width W1 of the gasket 24 between the magnetic disk 12 and the exposed area 72 is narrower than the width W2 of the gasket 24 between the magnetic disk 12 and the coating film 22. In other words, the width W1 of the thin portion 92 is narrower than the width W2 of the thick portion 91. The width of the gasket 24 is not limited to this example.

[0088] For example, the SFF-8300 form factor for 3.5-inch hard disk drives, developed by the Small Form Factor Committee, sets the maximum dimensions for HDDs. Specifically, the dimensions of HDD 10 are restricted in the X, Y, and Z directions. On the other hand, increasing the diameter of magnetic disk 12 increases the storage capacity of HDD 10.

[0089] When the diameter of the magnetic disk 12 increases due to the size restrictions of the HDD 10, the sidewall 32 becomes thinner near the ends P1, P2, and P3 of the magnetic disk 12. Generally, as the sidewall 32 becomes thinner, the width of the end surface 54 decreases, and the weld strength between the end surface 54 and the cover 25 may decrease.

[0090] The side wall 32 is protected by the paint film 22. Electrodeposition coating, which forms the paint film 22, has a lower thickness accuracy than machining, for example. To prevent interference between the inner cover 23 and the paint film 22, the inner cover 23 is separated from the paint film 22 on the coating area 71.

[0091] In this embodiment, the exposed area 72 is located near the ends P1, P2, and P3 of the magnetic disk 12. The exposed area 72 is formed, for example, by cutting, and thus has relatively high dimensional accuracy. Therefore, the distance between the protrusion 84 of the inner cover 23 and the exposed area 72 can be set short.

[0092] As described above, the exposed area 72 can be close to the inner cover 23. Therefore, the end surface 54 connected to the exposed area 72 can also be close to the inner cover 23. In other words, the end surface 54 can expand toward the inner cover 23 near the ends P1, P2, and P3 of the magnetic disk 12.

[0093] On the other hand, the coated region 71 is covered by the coating film 22 but is spaced apart from the magnetic disk 12. Therefore, even when the coated region 71 is close to the magnetic disk 12, a width sufficient to support the inner cover 23 and the gasket 24 can be provided on the support surface 53. In other words, even at a position spaced apart from the ends P1, P2, and P3 of the magnetic disk 12, the end surface 54 can expand toward the inner cover 23. Consequently, the end surface 54 can have a width sufficient to provide stable welding strength.

[0094] The inner cover 23 covers the magnetic disk 12 disposed in the inner space Si. Therefore, the size of the inner cover 23 is related to the size of the magnetic disk 12. As described above, the inner cover 23 can be close to the exposed area 72. Therefore, the inner cover 23 and the magnetic disk 12 can expand toward the exposed area 72, thereby increasing the storage capacity of the magnetic disk 12.

[0095] The exposed area 72 is not limited to cutting and can also be formed by other methods. For example, when the paint film 22 is provided on the second inner surface 52 by electrodeposition coating, a mask may be applied to cover the exposed area 72. By removing the mask, the exposed area 72 is exposed.

[0096] In the HDD 10 of the present embodiment described above, the magnetic disk 12 is rotatable about the central axis Axd. An internal space Si is provided in the base 21 for accommodating the magnetic disk 12. The base 21 has a first inner surface 51, a supporting surface 53, a second inner surface 52, and an end surface 54. The first inner surface 51 surrounds the magnetic disk 12. The supporting surface 53 is connected to the end of the first inner surface 51 in the +Z direction along the central axis Axd. The second inner surface 52 is farther from the central axis Axd than the first inner surface 51 and is connected to the supporting surface 53. The end surface 54 is connected to the end of the second inner surface 52 in the +Z direction. The coating film 22 covers at least a portion of the first inner surface 51, at least a portion of the supporting surface 53, and the coated area 71 of the second inner surface 52. The coating film 22 is separated from the end surface 54 and the exposed area 72 of the second inner surface 52. The exposed area 72 is aligned with the coated area 71 around the central axis Axd. The inner cover 23 is supported by the support surface 53 and surrounded by the second inner surface 52 to cover the internal space Si. The outer cover 25 is bonded to at least a portion of the base 21 to cover the inner cover 23 .

[0097] The paint film 22 protects a portion of the second inner surface 52, but its thickness sometimes varies. Meanwhile, an exposed area 72 of the second inner surface 52 is not covered by the paint film 22 and is exposed. The exposed area 72 can be formed, for example, by removing the paint film 22 through machining. Therefore, the distance between the exposed area 72 and the inner cover 23 can be set with high precision and shorter than the distance between the paint film 22 and the inner cover 23. Consequently, the HDD 10 can extend the inner cover 23 closer to the exposed area 72. Meanwhile, the exposed area 72 can be brought closer to the inner cover 23. Consequently, the HDD 10 can extend the end surface 54 connecting the exposed area 72 and the covered area 71 toward the inner cover 23. The outer cover 25 is generally bonded to the substrate 21 at or near the end surface 54. Therefore, the expansion of the end surface 54 can enhance the bonding strength between the substrate 21 and the outer cover 25. Furthermore, by widening the end surface 54, the HDD 10 can prevent the paint film 22 covering the second inner surface 52 from melting during welding. Furthermore, in the coated region 71, the paint film 22 covers the second inner surface 52. Therefore, compared to the case where the paint film 22 is removed over the entire circumference around the central axis Axd, the HDD 10 can reduce the work required to provide the exposed region 72 and can suppress a reduction in the area of ​​the coated region 71 protected by the paint film 22.

[0098] The exposed area 72 is closer to the magnetic disk 12 than the covered area 71. As described above, the inner cover 23 can be expanded to approach the exposed area 72. Therefore, the HDD 10 can increase the diameter of the magnetic disk 12 covered by the inner cover 23 and the storage capacity. Furthermore, the covered area 71 is spaced apart from the magnetic disk 12, allowing for flexible positioning.

[0099] The exposed area 72 includes exposed areas 72A, 72B, and 72C separated from each other about the central axis Axd. The base 21 extends in the +Y direction, which is perpendicular to the central axis Axd. In the projection plane viewed in the +Z direction, the exposed area 72A faces end P1 of the magnetic disk 12 in the +Y direction. The exposed area 72B faces end P2 of the magnetic disk 12 in the +X direction, which is perpendicular to the +Z and +Y directions. The exposed area 72C faces end P3 of the magnetic disk 12 in the -X direction, which is opposite to the +X direction.

[0100] Generally speaking, end P1 of the disk 12 in the +Y direction, end P2 of the disk 12 in the +X direction, and end P3 of the disk 12 in the -X direction are closer to the second inner surface 52 than other portions of the disk 12. Therefore, the width of the support surface 53 is narrower near ends P1, P2, and P3 of the disk 12 in the +Y, +X, and -X directions, but exposed areas 72A, 72B, and 72C are provided. The distance between each of the exposed areas 72A, 72B, and 72C and the inner cover 23 can be set short. Therefore, as described above, the HDD 10 can increase the diameter of the disk 12 and improve the bonding strength between the end surface 54 and the outer cover 25. Furthermore, the HDD 10 can reduce the work required to provide the exposed areas 72 and prevent a reduction in the area of ​​the coated area 71 protected by the coating film 22.

[0101] The base 21 further includes a second outer surface 57 located on the opposite side of the second inner surface 52 . A distance D1 between the exposed region 72 and the second outer surface 57 is shorter than a distance D2 between the covered region 71 and the second outer surface 57 .

[0102] For example, by cutting away the coating film 22 and the coated region 71, an exposed region 72 can be formed that is not covered by the coating film 22. By forming the exposed region 72, the HDD 10 can increase the diameter of the magnetic disk 12, as described above, thereby improving the bonding strength between the end face 54 and the cover 25. Furthermore, the width of the end face 54 between the coated region 71 and the second outer surface 57 can be increased. Consequently, the HDD 10 can improve the bonding strength between the end face 54 and the cover 25.

[0103] The distance D3 between the inner cover 23 and the exposed area 72 is shorter than the distance D4 between the inner cover 23 and the coating film 22. Thus, the HDD 10 can increase the diameter of the magnetic disk 12 as described above, and can improve the bonding strength between the end surface 54 and the outer cover 25.

[0104] Inner cover 23 has side surface 83 facing paint film 22 and projection 84 projecting from side surface 83 toward exposed area 72. Thus, HDD 10 can shorten the distance between inner cover 23 and exposed area 72 and suppress interference between side surface 83 and paint film 22.

[0105] The length L1 of the convex portion 84 around the central axis Axd is shorter than the length L2 of the exposed region 72. This can suppress the convex portion 84 from interfering with the paint film 22 near the exposed region 72.

[0106] The sealing gasket 24 is interposed between the support surface 53 and the inner cover 23. The sealing gasket 24 has a thick portion 91 and a thin portion 92. The thick portion 91 is located between the magnetic disk 12 and the coating film 22 in the projection plane viewed in the +Z direction. The thin portion 92 is located between the magnetic disk 12 and the exposed area 72 in the projection plane viewed in the +Z direction, and is curved so as to protrude from the thick portion 91 toward the exposed area 72.

[0107] The thin portion 92 is bent at a position corresponding to the exposed area 72 and the protrusion 84 so as to be separated from the edge of the support surface 53 connected to the first inner surface 51. As a result, the gasket 24 can prevent the thin portion 92 from falling off the support surface 53, thereby more reliably sealing the internal space Si.

[0108] The gasket 24 is interposed between the support surface 53 and the inner cover 23. In the projection plane viewed in the +Z direction, the width W1 of the gasket 24 between the magnetic disk 12 and the exposed area 72 is narrower than the width W2 of the gasket 24 between the magnetic disk 12 and the coating film 22.

[0109] Because the exposed area 72 is closer to the magnetic disk 12 than the covered area 71, the width of the support surface 53 is narrow near the exposed area 72. Since the width W1 of the gasket 24 is narrow near the exposed area 72, the gasket 24 is prevented from falling off the support surface 53, and the internal space Si can be sealed more reliably.

[0110] The outer cover 25 is joined to the end surface 54. As described above, the HDD 10 can expand the end surface 54 toward the inner cover 23, thereby increasing the joining strength between the end surface 54 and the outer cover 25.

[0111] The base 21 further includes a slope 55. The slope 55 extends between the second inner surface 52 and the end surface 54 at an angle relative to the second inner surface 52 and the end surface 54. The length of the slope 55 between the exposed region 72 and the end surface 54 is shorter than the length of the slope 55 between the covered region 71 and the end surface 54.

[0112] By shortening the inclined surface 55, it is possible to suppress a reduction in the width of the end surface 54 near the exposed region 72. Therefore, the HDD 10 can improve the bonding strength between the end surface 54 and the cover 25.

[0113] The diameter of the magnetic disk 12 is 96 mm or greater. Generally, when the diameter of the magnetic disk 12 is set larger, the distance between the second inner surface 52 and the magnetic disk 12 becomes narrower. However, as described above, the diameter of the magnetic disk 12 can be increased in the HDD 10, thereby improving the bonding strength between the end surface 54 and the cover 25.

[0114] Exposed area 72 is spaced from support surface 53 toward inner cover 23. HDD 10 can thereby prevent paint film 22 covering support surface 53 from being removed during cutting to form exposed area 72, thereby preventing reduction in the area of ​​support surface 53 protected by paint film 22.

[0115] Inner cover 23 is further away from support surface 53 than the end of exposed region 72 in −Z direction opposite to +Z direction. Thus, HDD 10 can suppress interference between paint film 22 and inner cover 23 provided between support surface 53 and exposed region 72 .

[0116] While several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments may be implemented in various other forms, and various omissions, substitutions, and modifications may be made without departing from the gist of the invention. These embodiments and their variations are included within the scope and gist of the invention and within the invention set forth in the claims and their equivalents.

Claims

1. A disk device comprising: A magnetic disk, capable of rotating around an axis of rotation; a base body having an internal space for accommodating the magnetic disk, and comprising a first inner surface surrounding the magnetic disk, a supporting surface connected to an end of the first inner surface in a first direction along the rotation axis, a second inner surface farther from the rotation axis than the first inner surface and connected to the supporting surface, and an end surface connected to an end of the second inner surface in the first direction; a film covering at least a portion of the first inner surface, at least a portion of the support surface, and a covered region of the second inner surface, and being spaced apart from the end surface and an exposed region of the second inner surface aligned with the covered region about the rotation axis; an inner cover supported by the support surface, surrounded by the second inner surface, and covering the inner space; and The outer cover is combined with at least a portion of the base and covers the inner cover.

2. The disk device according to claim 1, The exposed region is closer to the magnetic disk than the covered region.

3. The disk device according to claim 2, The exposed area includes a first exposed area, a second exposed area, and a third exposed area separated from each other around the rotation axis. The base extends in a second direction perpendicular to the rotation axis. In the projection surface observed in the first direction, the first exposed area is toward the end of the disk in the second direction, the second exposed area is toward the end of the disk in the third direction orthogonal to the first direction and the second direction, and the third exposed area is toward the end of the disk in the fourth direction opposite to the third direction.

4. The disk device according to claim 1, The base further has an outer surface located on the opposite side of the second inner surface, A distance between the exposed region and the outer surface is shorter than a distance between the covered region and the outer surface.

5. The disk device according to claim 1, A distance between the inner cover and the exposed area is shorter than a distance between the inner cover and the film.

6. The disk device according to claim 5, The inner cover has a side surface facing the film and a convex portion protruding from the side surface toward the exposed region.

7. The disk device according to claim 6, The length of the protrusion around the rotation axis is shorter than the length of the exposed area.

8. The disk device according to claim 6 or 7, The disk device also includes a sealing gasket, which has a first portion located between the disk and the membrane in the projection surface observed in the first direction, and a second portion located between the disk and the exposed area in the projection surface and bent so as to protrude from the first portion toward the exposed area, and the sealing gasket is interposed between the supporting surface and the inner cover.

9. The disk device according to claim 1, The disk device further includes a sealing gasket interposed between the support surface and the inner cover. In a projection plane viewed in the first direction, a width of the gasket between the magnetic disk and the exposed region is narrower than a width of the gasket between the magnetic disk and the film.

10. The disk device according to claim 1, The outer cover is combined with the end surface.

11. The disk device according to claim 10, The base further includes an inclined surface extending obliquely relative to the second inner surface and the end surface between the second inner surface and the end surface. The length of the inclined surface between the exposed region and the end surface is shorter than the length of the inclined surface between the covered region and the end surface.

12. The disk device according to claim 1, The diameter of the magnetic disk is greater than 96 mm.

13. The disk device according to claim 1, The exposed area is spaced apart from the supporting surface and faces the inner cover.

14. The disk device according to claim 13, The inner cover is located farther from the support surface than an end of the exposed region in a fifth direction opposite to the first direction.

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